Facultad de Ciencias Exactas y Naturales

Publicaciones 2017

BrO and inferred Br-y profiles over the western Pacific: relevance of inorganic bromine sources and a Br-y minimum in the aged tropical tropopause layer

Koenig, TK ;Volkamer, R ; Baidar, S ; Dix, B ; Wang, SY ; Anderson, DC ; Salawitch, RJ ; Wales, PA ; Cuevas, CA ; Fernandez, RP ; Saiz-Lopez, A ; Evans, MJ ; Sherwen, T ; Jacob, DJ ; Schmidt, J ; Kinnison, D ; Lamarque, JF ; Apel, EC ; Bresch, JC ; Campos, T ; Flocke, FM ; Hall, SR ; Honomichl, SB ; Hornbrook, R ; Jensen, JB ; Lueb, R ; Montzka, DD ; Pan, LL ; Reeves, JM ; Schauffler, SM ; Ullmann, K ; Weinheimer, AJ ; Atlas, EL ; Donets, V ; Navarro, MA ; Riemer, D ; Blake, NJ ; Chen, DX ; Huey, LG ; Tanner, DJ ; Hanisco, TF ; Wolfe, GM ; ATMOSPHERIC CHEMISTRY AND PHYSICS ,2017 ,17 ,15245 -15270 .

We report measurements of bromine monoxide (BrO) and use an observationally constrained chemical box model to infer total gas-phase inorganic bromine (Br-y) over the tropical western Pacific Ocean (tWPO) during the CONTRAST field campaign (January-February 2014). The observed BrO and inferred Bry profiles peak in the marine boundary layer (MBL), suggesting the need for a bromine source from sea-salt aerosol (SSA), in addition to organic bromine (CBry). Both profiles are found to be C-shaped with local maxima in the upper free troposphere (FT). The median tropospheric BrO vertical column density (VCD) was measured as 1 : 6 X 10(13) molec Cm-2, compared to model predictions of 0 : 9 X 10(13) molec cm(-2) in GEOS-Chem (CBry but no SSA source), 0 : 4 X 10(13) molec cm(-2) in CAM-Chem (CBry and SSA), and 2 : 1 X 10(13) molec cm(-2) in GEOS-Chem (CBry and SSA). Neither global model fully captures the C-shape of the Br-y profile. A local Br-y maximum of 3.6 ppt (2.9-4.4 ppt; 95% confidence interval, CI) is inferred between 9.5 and 13.5 km in air masses influenced by recent convective outflow. Unlike BrO, which increases from the convective tropical tropopause layer (TTL) to the aged TTL, gas-phase Br-y decreases from the convective TTL to the aged TTL. Analysis of gas-phase Br-y against multiple tracers (CFC-11, H2O = O-3 ratio, and potential temperature) reveals a Br-y minimum of 2.7 ppt (2.3-3.1 ppt; 95% CI) in the aged TTL, which agrees closely with a stratospheric injection of 2 : 6 X 0 : 6 ppt of inorganic Br-y (estimated from CFC-11 correlations), and is remarkably insensitive to assumptions about heterogeneous chemistry. Br-y increases to 6.3 ppt (5.6-7.0 ppt; 95% CI) in the stratospheric "middle-world" and 6.9 ppt (6.5-7.3 ppt; 95% CI) in the stratospheric "overworld". The local Br-y minimum in the aged TTL is qualitatively (but not quantitatively) captured by CAM-Chem, and suggests a more complex partitioning of gas-phase and aerosol Br-y species than previously recognized. Our data provide corroborating evidence that inorganic bromine sources (e.g., SSA-derived gas-phase Br-y) are needed to explain the gas-phase Br-y budget in the upper free troposphere and TTL. They are also consistent with observations of significant bromide in Upper Troposphere-Lower Stratosphere aerosols. The total Br-y budget in the TTL is currently not closed, because of the lack of concurrent quantitative measurements of gas-phase Br-y species (i.e., BrO, HOBr, HBr, etc.) and aerosol bromide. Such simultaneous measurements are needed to (1) quantify SSA-derived Br-y in the upper FT, (2) test Br-y partitioning, and possibly explain the gas-phase Bry Br-y minimum in the aged TTL, (3) constrain heterogeneous reaction rates of bromine, and (4) account for all of the sources of Br-y to the lower stratosphere.

A spectroscopic sensing platform for MARCKS protein monolayers

Klug, J ;Torresan, MF ; Lurgo, F ; Borioli, G ; Lacconi, GI ; JOURNAL OF COLLOID AND INTERFACE SCIENCE ,2017 ,508 ,532 -541 .

We developed a highly sensitive silicon platform, suitable to assess the molecular organization of protein samples. Prototype platforms were obtained using different electrochemical protocols for the electrode position of Ag-nanoparticles onto the hydrogenated silicon surface. A platform with high Surface Enhanced Raman Scattering efficiency was selected based on the surface coverage and the number density of particles size distribution. The performance of the platform was determined by studying the interaction of Myristoylated Alanine-Rich C Kinase Substrate (MARCKS) protein with the substrate according to its molecular organization. The chemical and structural characteristics of MARCKS molecules were examined under two configurations: i) a disordered distribution given by a MARCKS solution drop deposited onto the platform and, ii) a compact monolayer transferred to the platform by the Langmuir-Blodgett method. Raman spectra show vibrational bands of Phenylalanine and Lysine residues specific for the protein effector domain, and evidence the presence of alpha helix structure in both configurations. Moreover, we distinguished the supramolecular order between the compact monolayer and random molecular distribution. The platforms containing Ag-nanoparticles are suitable for studies of protein structure and interactions, advancing a methodological strategy for our long term goal, which is to explore the interaction of proteins with model membranes. (C) 2017 Elsevier Inc. All rights reserved.

High performance preconcentration of inorganic Se species by dispersive micro-solid phase extraction with a nanosilica-ionic liquid hybrid material

Llaver, M ;Coronado, EA ; Wuilloud, RG ; SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY ,2017 ,138 ,23 -30 .

A highly sensitive and efficient dispersive micro-solid phase extraction (D-mu-SPE) method was developed for inorganic Se speciation analysis. A novel ionic liquid (IL)-nanomaterial hybrid consisting of 1-dodecyl-3-methylimidazolium bromide-functionalized nanosilica was used for the efficient retention of Se(IV) complexed with ammonium pyrrolidine dithiocarbamate, followed by elution with an ethyl acetate/Triton X-114 mixture and determination by electrothermal atomic absorption spectroscopy. The Se(VI) species was selectively determined by difference between total inorganic Se and Se(IV) after pre-reduction. The IL-nanomaterial hybrid was characterized by Fourier transform infrared spectroscopy and transmission electronic microscopy. Likewise, Se(IV) sorption capacity of the retention material and maximum amount of IL loaded on its surface were determined. Several factors concerning the functionalization, extraction and elution steps were optimized, yielding a 100% extraction efficiency for Se(IV) under optimal conditions. A limit of detection of 1.1 ng L-1, a relative standard deviation of 5.7% and a 110-fold enhancement factor were obtained. The D-mu-SPE method was successfully applied to several water samples from different origins and compositions, including rain, tap, underground, river and sea. (C) 2017 Elsevier B.V. All rights reserved.

Synergistic analytical preconcentration with ionic liquid-nanomaterial hybrids

Martinis, EM ;Grijalba, AC ; Perez, MB ; Llaver, M ; Wuilloud, RG ; TRAC-TRENDS IN ANALYTICAL CHEMISTRY ,2017 ,97 ,333 -344 .

Nanomaterials and ionic liquids (ILs) have very attractive properties for improved analytical preconcentration methods. Thus, ILs have been used as excellent tools to functionalize nanomaterials, giving them specific chemical properties for higher selectivity, extraction efficiency and extended re-utilization in pre-concentration. Moreover, incorporation of IL-nanomaterial hybrids in miniaturized solid phase and liquid phase microextraction procedures is being increasingly exploited to obtain high analytical recoveries while developing environmentally friendly analytical methods. In this review, the design and application of innovative and efficient analytical methods for sensitive and selective determination of inorganic and organic analytes is described. The synthesis of some IL-nanomaterial hybrids is presented along with a revision of the most important synergistic physicochemical properties useful for the extraction of analytes. Finally, practical considerations concerning the application of IL-nanomaterial hybrids for the development of modern analytical separation and preconcentration techniques are fully discussed in this work. (C) 2017 Elsevier B.V. All rights reserved.

Reinforcements in avian wing bones: Experiments, analysis, and modeling

Novitskaya, E ;Ruestes, CJ ; Porter, MM ; Lubarda, VA ; Meyers, MA ; McKittrick, J ; JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS ,2017 ,76 ,85 -96 .

Almost all species of modern birds are capable of flight; the mechanical competency of their wings and the rigidity of their skeletal system evolved to enable this outstanding feat. One of the most interesting examples of structural adaptation in birds is the internal structure of their wing bones. In flying birds, bones need to be sufficiently strong and stiff to withstand forces during takeoff, flight, and landing, with a minimum of weight. The cross-sectional morphology and presence of reinforcing structures (struts and ridges) found within bird wing bones vary from species to species, depending on how the wings are utilized. It is shown that both morphology and internal features increases the resistance to flexure and torsion with a minimum weight penalty. Prototypes of reinforcing struts fabricated by 3D printing were tested in diametral compression and torsion to validate the concept. In compression, the ovalization decreased through the insertion of struts, while they had no effect on torsional resistance. An elastic model of a circular ring reinforced by horizontal and vertical struts is developed to explain the compressive stiffening response of the ring caused by differently oriented struts.

Middle to Late Miocene Contractional Deformation in Costa Rica Triggered by Plate Geodynamics

Mescua, JF ;Porras, H ; Duran, P ; Giambiagi, L ; de Moor, M ; Cascante, M ; Salazar, E ; Protti, M ; Poblete, F ; TECTONICS ,2017 ,36 ,2936 -2949 .

Contractional deformation in Costa Rica is usually attributed to the subduction of the aseismic Cocos Ridge. In this work, we review the evidences for contraction in the middle to late Miocene, prior to the arrival of the Cocos Ridge at the Middle America Trench. We find that the Miocene phase of contractional deformation is found in all of Costa Rica, probably extending to Nicaragua as well. The widespread distribution of this event requires a regional or plate geodynamic trigger. We analyze the possible mechanisms that could produce the onset of contractional deformation, using the better known case of subduction orogeny, the Andes, as an analog. We propose that a change in the direction of the Cocos plate since similar to 19 Ma led to a change from oblique to orthogonal convergence, producing contractional deformation of the upper plate.

Macroalgae of Iridaea cordata as an efficient biosorbent to remove hazardous cationic dyes from aqueous solutions

Escudero, LB ;Smichowski, PN ; Dotto, GL ; WATER SCIENCE AND TECHNOLOGY ,2017 ,76 ,3379 -3391 .

In the present work, Iridaea cordata (IC), a red marine macroalgae, was used as an efficient biosorbent for the removal of crystal violet (CV) and methylene blue (MB) dyes from aqueous solutions. The effects of pH (5, 7, and 9) and IC concentration (1, 3, and 5 g L-1) on the biosorption were studied through a 32 full factorial design. Under the optimal conditions (pH: 7, biosorbent concentration: 1 g L-1), biosorption kinetic studies were developed and the obtained experimental data were evaluated by pseudo-first order and pseudo-second order models. The results showed that the pseudo-second order model was in agreement with the experimental kinetic data for both dyes. Equilibrium studies were also carried out, and results exhibited good concordance with the Brunauer-Emmett-Teller isotherm. The biosorption capacities were 36.5 and 45.0 mg g(-1) for CV and MB dyes, respectively. The dye removal percentages were around 75% for CV and 90% for MB. Thermodynamically, the biosorption process proved to be exothermic, spontaneous, and favorable. These results showed that IC biomass is a promising biosorbent for removal of CV and MB dyes from aqueous solutions.

Thermodynamics of the melting process in Au nano-clusters: Phenomenology, energy, entropy and quasi-chemical modeling

Bertoldi, DS ;Millan, EN ; Guillermet, AF ; JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS ,2017 ,111 ,286 -293 .

The paper presents a thermodynamic study of the melting transition in Au nano-clusters with a number of atoms (N) in the range 10(3) < N < 10(6) using a Molecular Dynamics (MD) technique. This range of sizes allows an analysis of the relations between the properties of the clusters and macroscopic Au. Four steps in the progress of the transition occurring upon heating are identified on thermodynamic and structural basis, and the corresponding temperature ranges are determined. In particular, the step where most of the transition takes place (the "melting step") is identified and described in terms of the change in the relative amount of two kinds of atoms, viz., those forming solid phase-like (SPL) aggregates and those in the liquid phase-like (LPL) aggregates. The energy and entropy change involved in the "melting step" are established as a function of N. These properties are used to evaluate the temperature T-0 at which the SPL and the LPL have equal values of the Helmholtz energy. Furthermore, the possibility of describing the thermodynamics of the "melting step" by means of a formalism involving an isomerization-type reaction between the atoms in the SPL and the LPL is explored. To this aim, an equilibrium constant (K-eq) involving the concentration of such types of atoms is introduced. Finally, it is shown that a thermodynamic, van't Hoff analysis of the size-dependence of k(eq) yields values of the T-0 temperature which are in very good agreement with those obtained from the energy and entropy values.

Epididymal alpha-L-fucosidase and its possible role in remodelling the surface of bull spermatozoa

Aguilera, AC ;Boschin, V ; Robina, I ; Elias-Rodriguez, P ; Sosa, MA ; THERIOGENOLOGY ,2017 ,104 ,134 -141 .

The mammalian epididymis provides an appropriate environment for sperm maturation. During the epididymal transit, spermatozoa undergo biochemical and morphological changes that lead to the acquisition of the fertilizing capacity. In this study we analysed the fucosylation status of membrane glycoproteins in the spermatozoa obtained from different regions of the bull epididymis. High amounts of fucose were detected on caput spermatozoa (R.F.I. = 1010 +/- 20.35), mostly located in the post-acrosome zone. A significant decrease in the fucose levels was detected toward the cauda (R.F.I. = 540.5 +/- 49.93) (P < 0.05). This decrease was in line with the increased activity of alpha-L-fucosidase in the cauda fluid. In sperm from the cauda, the defucosylation occurred in some proteins, whereas others showed higher fucosylation rates. A significant decrease of fucose in the gametes was observed upon incubation of crude cauda fluid with caput spermatozoa (from R.F.I. = 1.45 +/- 0.08 to 1.06 +/- 0.03) (P < 0.05) indicating that the alpha-L-fucosidase present in the epididymal fluid is active on spermatozoa. Moreover, this effect was blocked with specific enzyme inhibitors. These results provide direct evidence that the alpha-L-fucosidase from epididymal fluid participates in the fucose removal from spermatozoa, as a step of sperm maturation in the bull epididymis. (C) 2017 Elsevier Inc. All rights reserved.

Collision-Induced Melting in Collisions of Water Ice Nanograins: Strong Deformations and Prevention of Bouncing

Nietiadi, ML ;Umstatter, P ; Alhafez, IA ; Rosandi, Y ; Bringa, EM ; Urbassek, HM ; GEOPHYSICAL RESEARCH LETTERS ,2017 ,44 ,10822 -10828 .

Collisions between ice grains are ubiquitous in the outer solar system. The mechanics of such collisions is traditionally described by the elastic contact theory of adhesive spheres. Here we use molecular dynamics simulations to study collisions between nanometer-sized amorphous water ice grains. We demonstrate that the collision-induced heating leads to grain melting in the interface of the colliding grains. The large lateral deformations and grain sticking induced considerably modify available macroscopic collision models. We report on systematic increases of the contact radius, strong grain deformations, and the prevention of grain bouncing.

3D chemometric model and frond architecture of Alethopteris ambigua (Medullosales): Implications for reconstruction and taxonomy

Zodrow, EL ;D'Angelo, JA ; Cleal, CJ ; PALAEONTOGRAPHICA ABTEILUNG B-PALAEOPHYTOLOGIE ,2017 ,295 ,91 -133 .

The postulated relationship between chemistry and frond architecture is further tested based on a 450 mm frond segment Alethopteris ambigua Lesquereux pars from the Sydney Coalfield (Canada), this being the largest specimen known for this species. Micromorphology demonstrated amphistomatic rachides with larger anomocytic stomata than on the hypostomatic pinnules, and rachial epidermal cells that are irregularly elongate to polygonal-rectangular, intermingled with more rectangular isodiametric cells, with hardly any change over the segment. Functional groups or chemical structural groups, however, are continuously variable over the frond segment, allowing meaningful comparisons between frond parts. Based on these data, a three-dimensional "model" is derived which explains the relationship between the frond architecture and changes in chemical structural groups. Furthermore, the aromatic-rich compounds correlate with robust and stiffer proximal frond parts, whereas the aliphatic-rich compounds correlate with the slender and flexible distal parts. The former reflects lignin-related compounds in the basal part of the frond, and the latter tannin and resin-like chemicals as secondary metabolites in pinnules and midveins as the defense against herbivory. Strengthening the relationship between the hypothesized fossil chemistry-frond architecture is the testable prediction of chemistry of the "missing parts" in the likely quadripinnate A. ambigua frond, i.e. the petiole, frond bifurcation, and their adjacent proximal and most robust parts.

Diet switching of seed-eating birds wintering in grazed habitats of the central Monte Desert, Argentina

Marone, L ;Olmedo, M ; Valdes, DY ; Zarco, A ; de Casenave, JL ; Pol, RG ; CONDOR ,2017 ,119 ,673 -682 .

Although bird population declines associated with land degradation are common, the initial response of organisms to rapid human-induced environmental change is usually behavioral. Reductions in seed availability due to cattle grazing may trigger diet switching in seed-eating birds, but empirical examples of such behavior are lacking. We asked whether cattle grazing changed the composition and reduced the size of seed reserves, and whether seed shortage caused diet shifts in 4 species of seed-eating birds wintering in the central Monte Desert, Argentina. We assessed the soil seed bank composition and the granivorous fraction of each species' diet. Digestive tract or crop contents were obtained by using the flushing method on individuals captured with mist nets, and seeds were sorted and assigned to 1 of 3 functional groups (small grass seeds, large and medium-sized grass seeds, or forb seeds). Cattle grazing reduced the abundance of the preferred large and medium-sized grass seeds by 60-90%. The grass-seed specialists Many colored Chaco Finch (Saltatricula multicolor) and Ringed Warbling-Finch (Microspingus torquatus) did not change their diets in grazed areas, but the expanding specialists Common Diuca-Finch (Diuca diuca) and Rufous-collared Sparrow (Zonotrichia capensis) incorporated increased proportions of small grass seeds as well as forb seeds into their diets. These results were correctly predicted from species-specific differences in feeding flexibility previously established in cafeteria experiments. Based on species-specific diet composition, the energy reward of seeds by unit mass consumed decreased moderately (5-21%) in the grazed sites for S. multicolor, M. torquatus, and D. diuca. Starch content was similar between grazing conditions for all 3 birds. Although such deficits might be compensated for by a slight increase in absolute mass of seeds or alternative food items consumed in degraded lands, substantial reduction in the availability of grass seeds may reduce the capacity of degraded lands to support specialist granivorous birds.

Statistical mechanics of few-particle systems: exact results for two useful models

Miranda, EN ;EUROPEAN JOURNAL OF PHYSICS ,2017 ,38 ,-.

The statistical mechanics of small clusters ( n similar to 10-50 elements) of harmonic oscillators and two-level systems is studied exactly, following the microcanonical, canonical and grand canonical formalisms. For clusters with several hundred particles, the results from the three formalisms coincide with those found in the thermodynamic limit. However, for clusters formed by a few tens of elements, the three ensembles yield different results. For a cluster with a few tens of harmonic oscillators, when the heat capacity per oscillator is evaluated within the canonical formalism, it reaches a limit value equal to k(B), as in the thermodynamic case, while within the microcanonical formalism the limit value is k(B)(1-1/n). This difference could be measured experimentally. For a cluster with a few tens of two-level systems, the heat capacity evaluated within the canonical and microcanonical ensembles also presents differences that could be detected experimentally. Both the microcanonical and grand canonical formalism show that the entropy is non-additive for systems this small, while the canonical ensemble reaches the opposite conclusion. These results suggest that the microcanonical ensemble is the most appropriate for dealing with systems with tens of particles.

Implications of biological factors on accumulation of persistent organic pollutants in Antarctic notothenioid fish

Rios, JM ;Lana, NB ; Ciocco, NF ; Covaci, A ; Barrera-Oro, E ; Moreira, E ; Altamirano, JC ; ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY ,2017 ,145 ,630 -639 .

In the present study, the possible associations between selected persistent organic pollutants (POPs) and biological factors were assessed in different tissues of two Antarctic notothenioid fish: Notothenia rossii (NOR) and Trematomus newnesi (TRN) collected at Potter Cove, King George Island/Isla 25 de Mayo, South Shetland Islands. Specifically, association patterns between biological factors (body size, lipid content, body condition) and POP concentrations (polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and metabolites, polybrominated diphenyl ethers (PBDEs), and hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), chlordanes (CHLs) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs)), were explored by using two approaches: multivariate analyses (principal component analysis: PCA) and intraspecific correlations. Integrating results suggest that biological factors such as size, KI and tissue type seemed to be associated to selective accumulation of POPs for immature specimens of N. rossii, and KI and tissue type for mature specimens of T. newnesi. Each particular factor should be considered when choosing N. rossii or T. newnesi as sentinels for POPs pollution in Antarctic marine environments. Further, both nototheniids showed a selective accumulation pattern in their gonads of penta-chlorinated biphenyls (penta-CBs; 55.5 and 29 ng g(-1) lw for N. rossii and T. newnesi, respectively) and organochlorine pesticides such as DDTs (199 and 13.3 ng g(-1) lw, for N. rossii and T. newnesi respectively), and of polybrominated diphenyl ethers (PBDEs) in gills (97.2 and 22.1 for ng g(-1) lw, for N. rossii and T. newnesi, respectively), highlighting the importance of these tissues in monitoring studies of pollution in fish. The current study expands the knowledge concerning the biological factors to be investigated when specific pollutants are monitored and supports the importance of tissue type for the selective accumulation of POPs in Antarctic fish. Additionally, a contribution to the scarce data on concentration of MeO-PBDEs in Antarctic marine organisms, particularly in the highly diverse perciform suborder Notothenioidei is provided.

Fire influences the structure of plant-bee networks

Peralta, G ;Stevani, EL ; Chacoff, NP ; Dorado, J ; Vazquez, DP ; JOURNAL OF ANIMAL ECOLOGY ,2017 ,86 ,1372 -1379 .

Fire represents a frequent disturbance in many ecosystems, which can affect plant-pollinator assemblages and hence the services they provide. Furthermore, fire events could affect the architecture of plant-pollinator interaction networks, modifying the structure and function of communities.

Dust-aggregate impact into granular matter: A systematic study of the influence of projectile velocity and size on crater formation and grain ejection

Planes, MB ;Millan, EN ; Urbassek, HM ; Bringa, EM ; ASTRONOMY & ASTROPHYSICS ,2017 ,607 ,-.

Context. Dust impact into granular materials leads to crater formation and material ejection. Aims. The impact of dust aggregates, composed of a number Np of grains, into a granular bed consisting of the same grains is studied as a function of impact velocity v and projectile size Np. No gravitational effects are included.

Formaldehyde in the Tropical Western Pacific: Chemical Sources and Sinks, Convective Transport, and Representation in CAM-Chem and the CCMI Models

Anderson, DC ;Nicely, JM ; Wolfe, GM ; Hanisco, TF ; Salawitch, RJ ; Canty, TP ; Dickerson, RR ; Apel, EC ; Baidar, S ; Bannan, TJ ; Blake, NJ ; Chen, DX ; Dix, B ; Fernandez, RP ; Hall, SR ; Hornbrook, RS ; Huey, LG ; Josse, B ; Jockel, P ; Kinnison, DE ; Koenig, TK ; Le Breton, M ; Marecal, V ; Morgenstern, O ; Oman, LD ; Pan, LL ; Percival, C ; Plummer, D ; Revell, LE ; Rozanov, E ; Saiz-Lopez, A ; Stenke, A ; Sudo, K ; Tilmes, S ; Ullmann, K ; Volkamer, R ; Weinheimer, AJ ; Zeng, G ; JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES ,2017 ,122 ,11201 -11226 .

Formaldehyde (HCHO) directly affects the atmospheric oxidative capacity through its effects on HOx. In remote marine environments, such as the tropical western Pacific (TWP), it is particularly important to understand the processes controlling the abundance of HCHO because model output from these regions is used to correct satellite retrievals of HCHO. Here we have used observations from the Convective Transport of Active Species in the Tropics (CONTRAST) field campaign, conducted during January and February 2014, to evaluate our understanding of the processes controlling the distribution of HCHO in the TWP as well as its representation in chemical transport/climate models. Observed HCHO mixing ratios varied from similar to 500 parts per trillion by volume (pptv) near the surface to similar to 75 pptv in the upper troposphere. Recent convective transport of near surface HCHO and its precursors, acetaldehyde and possibly methyl hydroperoxide, increased upper tropospheric HCHO mixing ratios by similar to 33% (22 pptv); this air contained roughly 60% less NO than more aged air. Output from the CAM-Chem chemistry transport model (2014 meteorology) as well as nine chemistry climate models from the Chemistry-Climate Model Initiative (free-running meteorology) are found to uniformly underestimate HCHO columns derived from in situ observations by between 4 and 50%. This underestimate of HCHO likely results from a near factor of two underestimate of NO in most models, which strongly suggests errors in NOx emissions inventories and/or in the model chemical mechanisms. Likewise, the lack of oceanic acetaldehyde emissions and potential errors in the model acetaldehyde chemistry lead to additional underestimates in modeled HCHO of up to 75 pptv (similar to 15%) in the lower troposphere.

Winter flock structure in the central Monte desert, Argentina

Zarco, A ;Cueto, VR ; ARDEA ,2017 ,105 ,89 -97 .

Flocking behaviour has been studied for decades around the world, but there is little knowledge of this subject in desert bird communities. We investigate winter flock structure in open woodlands of the central Monte desert, Argentina, during two consecutive years. Of the 22 bird species that were recorded in flocks, most were granivorous. There were differences in flock density between years, probably due to fluctuation in seed abundance. More than half of the observed flocks were composed of different species (i.e. mixed-species flocks). We detected only two regular species (found in more than 75% of flocks): Rufous-collared Sparrow Zonotrichia capensis and Ringed Warbling Finch Poospiza torquata, both granivorous birds. Ringed Warbling Finch and Cinnamon Warbling Finch Poospiza ornata co-occurred at a higher frequency than expected by chance, and formed subgroups within flocks. Many-colored Chaco Finch Saltatricula multicolor, Greater Wagtail-tyrant Stigmatura budytoides, Brown Cacholote Pseudoseisura lophotes and Short-billed Canastero Asthenes baeri were found to form family groups, which may be related to delayed natal dispersal. The observed flocking propensity of granivorous birds and the small number of species per flock were similar to that found in other desert bird communities. We discuss some differences and similarities between granivorous and insectivorous flocking patterns, and propose hypotheses on the plausible causes. Our results provide a basis for a better understanding of the flocking behaviour patterns of birds in arid environments.

Atomistic Studies of NanoindentationA Review of Recent Advances

Ruestes, CJ ;Alhafez, IA ; Urbassek, HM ; CRYSTALS ,2017 ,7 ,-.

This review covers areas where our understanding of the mechanisms underlying nanoindentation has been increased by atomistic studies of the nanoindentation process. While such studies have been performed now for more than 20 years, recent investigations have demonstrated that the peculiar features of nanoplasticity generated during indentation can be analyzed in considerable detail by this technique. Topics covered include: nucleation of dislocations in ideal crystals, effect of surface orientation, effect of crystallography (fcc, bcc, hcp), effect of surface and bulk damage on plasticity, nanocrystalline samples, and multiple (sequential) indentation. In addition we discuss related features, such as the influence of tip geometry on the indentation and the role of adhesive forces, and how pre-existing plasticity affects nanoindentation.

Targeting exogenous beta-Defensin to the endolysosomal compartment via a vehicle guided system

Carvelli, L ;Yuan, LB ; Esfandnia, S ; Zhang, Y ; Presley, JF ; Morales, CR ; HISTOLOGY AND HISTOPATHOLOGY ,2017 ,32 ,1017 -1027 .

A number of pathogens for which there are no effective treatments infect the cells via endocytosis. Once in the endosomes, the pathogens complete their life cycle by overriding normal lysosomal functions. Recently, our laboratory identified the lysosomal targeting signal of prosaposin, which is recognized by the sorting receptor "sortilin". Based on this evidence, we tested whether the antimicrobial peptide beta-Defensin linked to the targeting sequence of prosaposin (beta D-PSAP) could be redirected from its secretory pathway to the endolysosomal compartment. To this effect, beta D-PSAP was transfected into COS-7 cells. The sub-cellular distribution of beta D-PSAP was analyzed by confocal microscopy and differential centrifugation. Confocal microscopy demonstrated that beta D-PSAP overlaid with the lysosomal marker LAMP1, indicating that the construct reached endosomes and lysosomes. Differential centrifugation also showed that beta D-PSAP was in the lysosomal fractions. In addition, our binding inhibition assay demonstrated that beta D-PSAP bound specifically to sortilin. Similarly, the delivery of beta D-PSAP was abolished after overexpressing a truncated sortilin. These results indicate that the prosaposin C-terminus and D/C-domain (prosaposin targeting sequence) was an effective "guidance system" to redirect beta D-PSAP to the endolysosomal compartment. In the future, this and other fusion proteins with antimicrobial properties will be assembled to our "biotic vehicle" to target pathogens growing within these compartments.

Scale of human mobility in the southern Andes (Argentina and Chile): A new framework based on strontium isotopes

Barberena, R ;Duran, VA ; Novellino, P ; Winocur, D ; Benitez, A ; Tessone, A ; Quiroga, MN ; Marsh, EJ ; Gasco, A ; Cortegoso, V ; Lucero, G ; Llano, C ; Knudson, KJ ; AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY ,2017 ,164 ,305 -320 .

ObjectivesThe goal of this article is to assess the scale of human paleomobility and ecological complementarity between the lowlands and highlands in the southern Andes during the last 2,300 years. By providing isotope results for human bone and teeth samples, we assess a hypothesis of high residential mobility suggested on the basis of oxygen isotopes from human remains.

Diversity, distribution and dynamics of full-length Copia and Gypsy LTR retroelements in Solanum lycopersicum

Paz, RC ;Kozaczek, ME ; Rosli, HG ; Andino, NP ; Sanchez-Puerta, MV ; GENETICA ,2017 ,145 ,417 -430 .

Transposable elements are the most abundant components of plant genomes and can dramatically induce genetic changes and impact genome evolution. In the recently sequenced genome of tomato (Solanum lycopersicum), the estimated fraction of elements corresponding to retrotransposons is nearly 62%. Given that tomato is one of the most important vegetable crop cultivated and consumed worldwide, understanding retrotransposon dynamics can provide insight into its evolution and domestication processes. In this study, we performed a genome-wide in silico search of full-length LTR retroelements in the tomato nuclear genome and annotated 736 full-length Gypsy and Copia retroelements. The dispersion level across the 12 chromosomes, the diversity and tissue-specific expression of those elements were estimated. Phylogenetic analysis based on the retrotranscriptase region revealed the presence of 12 major lineages of LTR retroelements in the tomato genome. We identified 97 families, of which 77 and 20 belong to the superfamilies Copia and Gypsy, respectively. Each retroelement family was characterized according to their element size, relative frequencies and insertion time. These analyses represent a valuable resource for comparative genomics within the Solanaceae, transposon-tagging and for the design of cultivar-specific molecular markers in tomato.

alpha-SNAP is expressed in mouse ovarian granulosa cells and plays a key role in folliculogenesis and female fertility

Arcos, A ;de Paola, M ; Gianetti, D ; Acuna, D ; Velasquez, ZD ; Miro, MP ; Toro, G ; Hinrichsen, B ; Munoz, RI ; Lin, Y ; Mardones, GA ; Ehrenfeld, P ; Rivera, FJ ; Michaut, MA ; Batiz, LF ; SCIENTIFIC REPORTS ,2017 ,7 ,-.

The balance between ovarian folliculogenesis and follicular atresia is critical for female fertility and is strictly regulated by a complex network of neuroendocrine and intra-ovarian signals. Despite the numerous functions executed by granulosa cells (GCs) in ovarian physiology, the role of multifunctional proteins able to simultaneously coordinate/modulate several cellular pathways is unclear. Soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (alpha-SNAP) is a multifunctional protein that participates in SNARE-mediated membrane fusion events. In addition, it regulates cell-to-cell adhesion, AMPK signaling, autophagy and apoptosis in different cell types. In this study we examined the expression pattern of a-SNAP in ovarian tissue and the consequences of alpha-SNAP (M105I) mutation (hyh mutation) in folliculogenesis and female fertility. Our results showed that alpha-SNAP protein is highly expressed in GCs and its expression is modulated by gonadotropin stimuli. On the other hand, a-SNAP-mutant mice show a reduction in a-SNAP protein levels. Moreover, increased apoptosis of GCs and follicular atresia, reduced ovulation rate, and a dramatic decline in fertility is observed in a-SNAP-mutant females. In conclusion, a-SNAP plays a critical role in the balance between follicular development and atresia. Consequently, a reduction in its expression/function (M105I mutation) causes early depletion of ovarian follicles and female subfertility.

Permanent modifications in silica produced by ion-induced high electronic excitation: experiments and atomistic simulations

Rivera, A ;Olivares, J ; Prada, A ; Crespillo, ML ; Caturla, MJ ; Bringa, EM ; Perlado, JM ; Pena-Rodriguez, O ; SCIENTIFIC REPORTS ,2017 ,7 ,-.

The irradiation of silica with ions of specific energy larger than similar to 0.1 MeV/u produces very high electronic excitations that induce permanent changes in the physical, chemical and structural properties and give rise to defects (colour centres), responsible for the loss of sample transparency at specific bands. This type of irradiation leads to the generation of nanometer-sized tracks around the ion trajectory. In situ optical reflection measurements during systematic irradiation of silica samples allowed us to monitor the irradiation-induced compaction, whereas ex situ optical absorption measurements provide information on colour centre generation. In order to analyse the results, we have developed and validated an atomistic model able to quantitatively explain the experimental results. Thus, we are able to provide a consistent explanation for the size of the nanotracks, the velocity and thresholding effects for track formation, as well as, the colour centre yield per ion and the colour centre saturation density. In this work we will discuss the different processes involved in the permanent modification of silica: collective atomic motion, bond breaking, pressure-driven atom rearrangement and ultra-fast cooling. Despite the sudden lattice energy rise is the triggering and dominant step, all these processes are important for the final atomic configuration.

Southern Annular Mode drives multicentury wildfire activity in southern South America

Holz, A ;Paritsis, J ; Mundo, IA ; Veblen, TT ; Kitzberger, T ; Williamson, GJ ; Araoz, E ; Bustos-Schindler, C ; Gonzalez, ME ; Grau, HR ; Quezada, JM ; PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF ,2017 ,114 ,9552 -9557 .

The Southern Annular Mode (SAM) is the main driver of climate variability at mid to high latitudes in the Southern Hemisphere, affecting wildfire activity, which in turn pollutes the air and contributes to human health problems and mortality, and potentially provides strong feedback to the climate system through emissions and land cover changes. Here we report the largest Southern Hemisphere network of annually resolved tree ring fire histories, consisting of 1,767 fire-scarred trees from 97 sites (from 22 05 to 54 05) in southern South America (SAS), to quantify the coupling of SAM and regional wildfire variability using recently created multicentury proxy indices of SAM for the years 1531-2010 AD. We show that at interannual time scales, as well as at multidecadal time scales across 37-54 degrees s, latitudinal gradient elevated wildfire activity is synchronous with positive phases of the SAM over the years 1665-1995. Positive phases of the SAM are associated primarily with warm conditions in these biomass-rich forests, in which widespread fire activity depends on fuel desiccation. Climate modeling studies indicate that greenhouse gases will force SAM into its positive phase even if stratospheric ozone returns to normal levels, so that climate conditions conducive to widespread fire activity in SAS will continue throughout the 21st century.

Fire history in southern Patagonia: human and climate influences on fire activity in Nothofagus pumilio forests

Mundo, IA ;Villalba, R ; Veblen, TT ; Kitzberger, T ; Holz, A ; Paritsis, J ; Ripalta, A ; ECOSPHERE ,2017 ,8 ,-.

Fire is a major disturbance affecting forests worldwide with significant economic, social, and ecological impacts. The southernmost forests on Earth extend continuously along the Andes from mid-to subantarctic latitudes in South America. In this region, warming and drying trends since the mid-20th century have been linked to a positive trend in the Southern Annual Mode (SAM), the leading mode of extratropical climate variability in the Southern Hemisphere. Due to the scarcity of documentary fire records and the lack of tree-ring fire histories, little is known about how wildfire activity responds to shifts in the westerly circulation pattern and associated climatic variability in the Andean region south of similar to 44 degrees S. For the first time, we applied dendrochronological techniques to reconstruct fire history from the angiosperm Nothofagus pumilio at 16 sites distributed from similar to 44 degrees to 50 degrees S to determine relationships between fire occurrence and the two primary drivers of wildfire activity: climate variability and human activities. Partial cross-sections with fire scars were collected from 363 trees in Argentina and Chile. Chronologies of annually resolved fire-scar dates start in 1791 and show a pattern of higher fire frequency during the 20th century, concurrent with the human occupation and colonization processes in southern Patagonia. Years of widespread fire occurring synchronously in two or more disjunct sites are associated with broad-scale climatic anomalies. Intense droughts inferred from extreme departures in temperature, precipitation, and the Standardized Precipitation-Evapotranspiration Index (SPEI) during the growing seasons of 1944 and 1962 are consistent with the two most severe fires at northern sites. Extended droughts, reflected by the association of fire occurrence with six-month cumulative precipitation and SPEI, create conditions for widespread fires at the southern sites (south of similar to 46 degrees S). Regional fires were concurrent with significant positive departures of SAM during the austral spring-summer. This tree-ring fire record reveals the influences of both climate variability and human activities on fire in the N. pumilio forests across the Andes, and also establishes the feasibility of using this tree species as a natural archive of fire history.

Riparian rehabilitation planning in an urban-rural gradient: Integrating social needs and ecological conditions

Guida-Johnson, B ;Zuleta, GA ; AMBIO ,2017 ,46 ,578 -587 .

In the present context of global change and search for sustainability, we detected a gap between restoration and society: local communities are usually only considered as threats or disturbances when planning for restoration. To bridge this gap, we propose a landscape design framework for planning riparian rehabilitation in an urban-rural gradient. A spatial multi-criteria analysis was used to assess the priority of riversides by considering two rehabilitation objectives simultaneously-socio-environmental and ecological-and two sets of criteria were designed according to these objectives. The assessment made it possible to identify 17 priority sites for riparian rehabilitation that were associated with different conditions along the gradient. The double goal setting enabled a dual consideration of citizens, both as beneficiaries and potential impacts to rehabilitation, and the criteria selected incorporated the multi-dimensional nature of the environment. This approach can potentially be adapted and implemented in any other anthropic-natural interface throughout the world.

Nanotechnology, a new paradigm in atherosclerosis treatment

Gimenez, VMM ;Ruiz-Roso, MB ; Camargo, AB ; Kassuha, D ; Manucha, W ; CLINICA E INVESTIGACION EN ARTERIOSCLEROSIS ,2017 ,29 ,224 -230 .

Atherosclerosis, a known and prevalent disease, causes progressive deterioration of affected vessels, inducing a blood flow reduction with different complications, and its symptoms usually manifest in advanced stages of the disease. Therefore, the classic therapeutic alternatives are insufficient because the damages are many times irreversible. For this reason, there is a need to implement intelligent forms of drug administration and develop new therapeutic targets that reduce the progression of atherosclerotic lesion. The implementation of new tools for prevention, diagnosis and treatment of this cardiovascular disease is of special interest, focusing our attention on achieving a more effective control of the immune system. Finally, this review highlights the latest knowledge about nanotechnology as a powerful, modern, and promising therapeutic alternative applied to atherosclerotic disease, as well as warning of the potential complications with their use. (C) 2016 Sociedad Espanola de Arteriosclerosis. Published by Elsevier Espana, S.L.U. All rights reserved.

Performance analysis and comparison of cellular automata GPU implementations

Millan, EN ;Wolovick, N ; Piccoli, MF ; Garino, CG ; Bringa, EM ; CLUSTER COMPUTING-THE JOURNAL OF NETWORKS SOFTWARE TOOLS AND ,2017 ,20 ,2763 -2777 .

Cellular automata (CA) models are of interest to several scientific areas, and there is a growing interest in exploring large systems which would need high performance computing. In this work a CA implementation is presented which performs well in five different NVIDIA GPU architectures, from Tesla to Maxwell, simulating systems with up to a billion cells. Using the game of life (GoL) and a more complex variation of GoL as examples, a performance of 5.58e6 evaluated cells/s is achieved. The two optimizations most often used in previous studies are the use of shared memory and Multicell algorithms. Here, these optimizations do not improve performance in Fermi or newer architectures. The GoL CA code running in an NVIDIA Titan X obtained a speedup of up to similar to 85 x and up to similar to 230 x for a more complex CA, compared to an optimized serial CPU implementation. Finally, the efficiency of each GPU is analyzed in terms of cell performance/transistors and cell performance/bandwidth showing how the architectures improved for this particular problem.

Powdered grape seeds (PGS) as an alternative biosorbent to remove pharmaceutical dyes from aqueous solutions

Vanni, G ;Escudero, LB ; Dotto, GL ; WATER SCIENCE AND TECHNOLOGY ,2017 ,76 ,1177 -1187 .

An alternative, low-cost and efficient biosorbent, powdered grape seeds (PGS), was prepared from wastes of a wine industry, and used to remove brilliant blue (BB) and amaranth red (AR) dyes from aqueous solutions. The biosorbent was properly characterized before and after the biosorption operation. The potential of PGS to remove BB and AR dyes was investigated thought kinetic, isotherm and thermodynamic studies. The biosorption of BB and AR was favored at pH 1.0 using biosorbent dosage of 0.500 g L-1, being attained more than 85% of removal percentage. For BB and AR dyes, pseudo-second-order and Elovich models were able to explain the biosorption kinetic. The biosorption equilibrium of BB on PGS was well represented by the Langmuir model, while for AR, the Sips model was the most adequate. The maximum biosorption capacities were 599.5 and 94.2 mg g(-1) for BB and AR, respectively. The biosorption of BB and AR on PGS was a spontaneous, favorable and endothermic process. These findings indicated that PGS is a low-cost and efficient biosorbent, which can be used to treat dye containing waters.

Inducing Porosity on Hollow Nanoparticles by Hypervelocity Impacts

Valencia, FJ ;Gonzalez, RI ; Valdivia, JA ; Kiwi, M ; Bringa, EM ; Rogan, J ; JOURNAL OF PHYSICAL CHEMISTRY C ,2017 ,121 ,17856 -17861 .

The large surface-to-volume ratio of hollow palladium nanoparticles (hNPs) offers room to improve their hydrogen storage capacity as well as their catalytic activity. However, a less explored possibility is to use, in addition, the internal cavity. Here we explore, through classical molecular dynamics, the possibility of boring channels across the hNP wall by collision with solid Pd nanoprojectiles at high velocities, as well as their resilience to maintain their spherical geometry. We choose a stable hNP with an inner diameter of 13 nm and an outer diameter of 15 nm. The projectiles are Pd NPs of 1.5, 2.4, and 3.0 nm, respectively. We consider collision speeds between 3 and 15 km/s, with an impact parameter between 0 to 7 nm. Four different regimes, as a function of kinetic energy and impact parameter of the projectile, are found. For low speeds, the projectile is not able to penetrate the target and only creates surface craters. For a narrow range of intermediate speeds, the projectile enters the target, but the hNP shell is able to self-heal, either totally or partially. For large speeds, the projectile penetrates the target without altering its spherical hollow geometry, but for even larger speeds, the hNP collapses into a solid structure. The specific threshold speed for each regime depends on the mass and speed of the projectile. In all noncollapsing cases, the results show a linear relationship between projectile kinetic energy and crater or perforation size. We also studied its behavior when the hNP suffers successive collisions, finding that it keeps its hollow shape but forms faceted structures, such as nanoframes or hollow cuboctahedron nanoparticles. All of our results suggest that Pd hNPs, with adequate combinations of external radius and thickness are very robust, can withstand hypervelocity impacts and that channels can be opened to allow molecules to reach the internal cavity.

Modeling the inorganic bromine partitioning in the tropical tropopause layer over the eastern and western Pacific Ocean

Navarro, MA ;Saiz-Lopez, A ; Cuevas, CA ; Fernandez, RP ; Atlas, E ; Rodriguez-Lloveras, X ; Kinnison, D ; Lamarque, JF ; Tilmes, S ; Thornberry, T ; Rollins, A ; Elkins, J ; Hintsa, EJ ; Moore, FL ; ATMOSPHERIC CHEMISTRY AND PHYSICS ,2017 ,17 ,9917 -9930 .

The stratospheric inorganic bromine (Br-y)burden arising from the degradation of brominated very short-lived organic substances (VSLorg) and its partitioning between reactive and reservoir species is needed for a comprehensive assessment of the ozone depletion potential of brominated trace gases. Here we present modeled inorganic bromine abundances over the Pacific tropical tropopause based on aircraft observations of VSLorg from two campaigns of the Airborne Tropical TRopopause EXperiment (ATTREX 2013, carried out over the eastern Pacific, and ATTREX 2014, carried out over the western Pacific) and chemistry-climate simulations (along ATTREX flight tracks) using the specific meteorology prevailing. Using the Community Atmosphere Model with Chemistry (CAM-Chem) we model that BrO and Br are the daytime dominant species. Integrated across all ATTREX flights, BrO represents similar to 43 and 48% of daytime Bry abundance at 17 km over the western and eastern Pacific, respectively. The results also show zones where Br / BrO > 1 depending on the solar zenith angle (SZA), ozone concentration, and temperature. On the other hand, BrCl and BrONO2 were found to be the dominant nighttime species with similar to 61 and 56% of abundance at 17 km over the western and eastern Pacific, respectively. The western-to-eastern differences in the partitioning of inorganic bromine are explained by different abundances of ozone (O-3), nitrogen dioxide (NO2), total inorganic chlorine (Cl-y), and the efficiency of heterogeneous reactions of bromine reservoirs (mostly BrONO2 and HBr) occurring on ice crystals.

Topological Kondo insulators in one dimension: Continuous Haldane-type ground-state evolution from the strongly interacting to the noninteracting limit

Lisandrini, FT ;Lobos, AM ; Dobry, AO ; Gazza, CJ ; PHYSICAL REVIEW B ,2017 ,96 ,-.

We study, by means of the density-matrix renormalization group (DMRG) technique, the evolution of the ground state in a one-dimensional topological insulator, from the noninteracting to the strongly interacting limit, where the system can be mapped onto a topological Kondo-insulator model. We focus on a toy model Hamiltonian ( i.e., the interacting "sp-ladder" model), which could be experimentally realized in optical lattices with higher orbitals loaded with ultracold fermionic atoms. Our goal is to shed light on the emergence of the strongly interacting ground state and its topological classification as the Hubbard U interaction parameter of the model is increased. Our numerical results show that the ground state can be generically classified as a symmetry-protected topological phase of the Haldane type, even in the noninteracting case U = 0 where the system can be additionally classified as a time-reversal Z(2)-topological insulator, and evolves adiabatically between the noninteracting and strongly interacting limits.

Environmental and species-specific controls on delta C-13 and delta N-15 in dominant woody plants from central-western Argentinian drylands

Gatica, MG ;Aranibar, JN ; Pucheta, E ; AUSTRAL ECOLOGY ,2017 ,42 ,533 -543 .

Spatial variation in mean annual precipitation is the principal driver of plant water and nitrogen status in drylands. The natural abundance of carbon stable isotopes (delta C-13) in photosynthetic tissues of C3 plants is an indicator of time-integrated behaviour of stomatal conductance; while that of nitrogen stable isotopes (delta N-15) is an indicator of the main source of plant N (soil N vs. atmospheric N-2). Previous studies in drylands have documented that plant delta C-13 and delta N-15 values increase with decreasing mean annual precipitation due to reductions in stomatal conductance, and soil enriched in N-15, respectively. However, evidence for this comes from studies focused on stable isotopes measurements integrated at the plant community level or on dominant plants at the site level, but little effort has been made to study C and N isotope variations within a species growing along rainfall gradients. We analysed plant delta C-13, delta N-15 and C/N values of three woody species having different phenological leaf traits (deciduous, perennial and aphyllous) along a regional mean annual precipitation gradient from the central-western Argentinian drylands. Noticeably, plant delta C-13 and delta N-15 values in the three woody species did not increase towards sites with low precipitation or at the start of the growing season (drier period), as we expected. These results suggest that environmental factors other than mean annual precipitation may be affecting plant delta C-13 and delta N-15. The short-term environmental conditions may interact with species-specific plant traits related to water and nitrogen use strategies and override the predictive influence of the mean annual precipitation on plant delta C-13 and delta N-15 widely reported in drylands.

Analytical methods for bioactive sulfur compounds in Allium: An integrated review and future directions

Ramirez, DA ;Locatelli, DA ; Gonzalez, RE ; Cavagnaro, PF ; Camargo, AB ; JOURNAL OF FOOD COMPOSITION AND ANALYSIS ,2017 ,61 ,4 -19 .

Plant organosulfur compounds represent one of the main groups of phytochemicals that evidence an ample spectrum of biological activities. There are two major sources of sulfur-containing compounds in plant foods; Allium vegetables, such as garlic, onion, and leek; and cruciferous vegetables, such as broccoli, cabbage, and cauliflower. Among them, garlic is the most studied species, mainly due to the multiple health-enhancing effects attributed to its consumption. Most of these properties have been attributed to organosulfur compounds. Thus, knowledge on the analytical determinations available for the main bioactive sulfur compounds in Allium is of interest. In the present review, an extensive bibliographic survey was performed to compile information regarding the different methodologies that can be used for the determination of alk(en)yl cysteine sulfoxides (ACSOs), S-allyl cysteine (SAC), thiosulfinates (mainly allicin), diallyl, mono- di-, and tri-sulfides, vinyldithiins and (E)- and (Z)-ajoene, as influenced by plant matrices and other factors. The gathered information was analyzed and presented in a systemic and comparative way, describing advantages and disadvantages of the methodologies, considering both extractive and separative techniques, the type of matrices, columns and analytical performance data. In addition, new trends and future prospects for the analysis of sulfur compounds in plants were critically discussed. (C) 2016 Elsevier Inc. All rights reserved.

Tackling variability: A multicenter study to provide a gold-standard network approach for frontotemporal dementia

Sedeno, L ;Piguet, O ; Abrevaya, S ; Desmaras, H ; Garcia-Cordero, I ; Baez, S ; de la Fuente, LA ; Reyes, P ; Tu, SC ; Moguilner, S ; Lori, N ; Landin-Romero, R ; Matallana, D ; Slachevsky, A ; Torralva, T ; Chialvo, D ; Kumfor, F ; Garcia, AM ; Manes, F ; Hodges, JR ; Ibanez, A ; HUMAN BRAIN MAPPING ,2017 ,38 ,3804 -3822 .

Biomarkers represent a critical research area in neurodegeneration disease as they can contribute to studying potential disease-modifying agents, fostering timely therapeutic interventions, and alleviating associated financial costs. Functional connectivity (FC) analysis represents a promising approach to identify early biomarkers in specific diseases. Yet, virtually no study has tested whether potential FC biomarkers prove to be reliable and reproducible across different centers. As such, their implementation remains uncertain due to multiple sources of variability across studies: the numerous international centers capable conducting FC research vary in their scanning equipment and their samples' socio-cultural background, and, more troublingly still, no gold-standard method exists to analyze FC. In this unprecedented study, we aim to address both issues by performing the first multicenter FC research in the behavioral-variant frontotemporal dementia (bvFTD), and by assessing multiple FC approaches to propose a gold-standard method for analysis. We enrolled 52 bvFTD patients and 60 controls from three international clinics (with different fMRI recording parameters), and three additional neurological patient groups. To evaluate FC, we focused on seed analysis, inter-regional connectivity, and several graph-theory approaches. Only graph-theory analysis, based on weighted-matrices, yielded consistent differences between bvFTD and controls across centers. Also, graph metrics robustly discriminated bvFTD from the other neurological conditions. The consistency of our findings across heterogeneous contexts highlights graph-theory as a potential gold-standard approach for brain network analysis in bvFTD. Hum Brain Mapp 38:3804-3822, 2017. (c) 2017 Wiley Periodicals, Inc.

Hillock formation on nanocrystalline diamond

Valencia, FJ ;Gonzalez, RI ; Bringa, EM ; Kiwi, M ; CARBON ,2017 ,119 ,219 -224 .

Hillock formation on nanocrystalline (nc) diamond under swift heavy ion irradiation is studied by means of classical molecular dynamics. The irradiation is simulated by means of a thermal spike model, the nc samples include as many as 5 millions atoms. Our results show that hillocks on nc diamond can be created for stopping powers (SPe) in the range of 12-17 keV/nm, and grain sizes less than 13 nm. For smaller values of the SPe only point defects are observed on the nc surface, while for larger SPe hillocks suffer a transition to crater-rim, because of the increased sputtering that is due to the large energy that the ions deposit. We observe that the sputtering yields depend quadratically on the stopping power, contrary to what has been obtained by simulations for some single crystal solids. In addition, our results show that hillocks are smaller for 5 and 7 nm grain sizes, due to the large free volume that is available on the grain boundaries. Instead, for 10 and 13 nm the hillock is limited only to the amorphization of the grain closest to the surface. No hillock formation is expected for larger grain sizes, because of the transition of the nc to pristine diamond, where no hillock formation has been observed. (C) 2017 Elsevier Ltd. All rights reserved.

Hypothyroidism decreases JAK/STAT signaling pathway in lactating rat mammary gland

Arbocco, FCV ;Persia, FA ; Hapon, MB ; Jahn, GA ; MOLECULAR AND CELLULAR ENDOCRINOLOGY ,2017 ,450 ,14 -23 .

Thyroid pathologies have deleterious effects on lactation. Especially hypothyroidism (HypoT) induces premature mammary involution at the end of lactation and decreases milk production and quality in mid lactation. Milk synthesis is controlled by JAK2/STAT5 signaling pathway and prolactin (PRL), which activates the pathway. In this work we analyzed the effect of chronic 6-propyl-2-thiouracil (PTU)-induced HypoT on PRL signaling pathway on mammary glands from rats on lactation (L) days 2, 7 and 14. HypoT decreased prolactin receptor expression, and expression and activation of Stat5a/b protein. Expression of members of the SOCS-CIS family, inhibitors of the JAK-STAT pathway, decreased in L2 and L7, possibly as a compensatory response of the mammary cells to maintain PRL responsiveness. However, on L14, the level of these inhibitors was normal and the transcription of alpha-lactoalbumin (lalba), a target gene of the PRL pathway, decreased by half. HypoT altered the transcriptional capacity of the cell and decreased mRNA levels of Prlr and Stat5b on L14. Stat5b gene has functional thyroid hormone response elements in the regulatory regions, that bind thyroid hormone receptor beta (TR beta) differentially and in a thyroid hormone dependent manner. The overall decrease in the PRL signaling pathway and consequently in target gene (lalba) mRNA transcription explain the profound negative impact of HypoT on mammary function through lactation. (C) 2017 Elsevier B.V. All rights reserved.

Data Descriptor: A global multiproxy database for temperature reconstructions of the Common Era

Emile-Geay, J ;McKay, NP ; Kaufman, DS ; von Gunten, L ; Wang, JG ; Anchukaitis, KJ ; Abram, NJ ; Addison, JA ; Curran, MAJ ; Evans, MN ; Henley, BJ ; Hao, ZX ; Martrat, B ; McGregor, HV ; Neukom, R ; Pederson, GT ; Stenni, B ; Thirumalai, K ; Werner, JP ; Xu, CX ; Divine, DV ; Dixon, BC ; Gergis, J ; Mundo, IA ; Nakatsuka, T ; Phipps, SJ ; Routson, CC ; Steig, EJ ; Tierney, JE ; Tyler, JJ ; Allen, KJ ; Bertler, NAN ; Bjorklund, J ; Chase, BM ; Chen, MT ; Cook, E ; de Jong, R ; DeLong, KL ; Dixon, DA ; Ekaykin, AA ; Ersek, V ; Filipsson, HL ; Francus, P ; Freund, MB ; Frezzotti, M ; Gaire, NP ; Gajewski, K ; Ge, QS ; Goosse, H ; Gornostaeva, A ; Grosjean, M ; Horiuchi, K ; Hormes, A ; Husum, K ; Isaksson, E ; Kandasamy, S ; Kawamura, K ; Kilbourne, KH ; Koc, N ; Leduc, G ; Linderholm, HW ; Lorrey, AM ; Mikhalenko, V ; Mortyn, PG ; Motoyama, H ; Moy, AD ; Mulvaney, R ; Munz, PM ; Nash, DJ ; Oerter, H ; Opel, T ; Orsi, AJ ; Ovchinnikov, DV ; Porter, TJ ; Roop, HA ; Saenger, C ; Sano, M ; Sauchyn, D ; Saunders, KM ; Seidenkrantz, MS ; Severi, M ; Shao, XM ; Sicre, MA ; Sigl, M ; Sinclair, K ; St George, S ; St Jacques, JM ; Thamban, M ; Thapa, UK ; Thomas, ER ; Turney, C ; Uemura, R ; Viau, AE ; Vladimirova, DO ; Wahl, ER ; White, JWC ; Yu, ZC ; Zinke, J ; SCIENTIFIC DATA ,2017 ,4 ,-.

Reproducible climate reconstructions of the Common Era (1 CE to present) are key to placing industrial-era warming into the context of natural climatic variability. Here we present a community-sourced database of temperature-sensitive proxy records from the PAGES2k initiative. The database gathers 692 records from 648 locations, including all continental regions and major ocean basins. The records are from trees, ice, sediment, corals, speleothems, documentary evidence, and other archives. They range in length from 50 to 2000 years, with a median of 547 years, while temporal resolution ranges from biweekly to centennial. Nearly half of the proxy time series are significantly correlated with HadCRUT4.2 surface temperature over the period 1850-2014. Global temperature composites show a remarkable degree of coherence between high-and low-resolution archives, with broadly similar patterns across archive types, terrestrial versus marine locations, and screening criteria. The database is suited to investigations of global and regional temperature variability over the Common Era, and is shared in the Linked Paleo Data (LiPD) format, including serializations in Matlab, R and Python.

The bouncing threshold in silica nanograin collisions

Nietiadi, ML ;Umstatter, P ; Tjong, T ; Rosandi, Y ; Millan, EN ; Bringa, EM ; Urbassek, HM ; PHYSICAL CHEMISTRY CHEMICAL PHYSICS ,2017 ,19 ,16555 -16562 .

Using molecular dynamics simulations, we study collisions between amorphous silica nanoparticles. Our silica model contains uncontaminated surfaces, that is, the effect of surface hydroxylation or of adsorbed water layers is excluded. For central collisions, we characterize the boundary between sticking and bouncing collisions as a function of impact velocity and particle size and quantify the coefficient of restitution. We show that the traditional Johnson-Kendall-Roberts (JKR) model provides a valid description of the ingoing trajectory of two grains up to the moment of maximum compression. The distance of closest approach is slightly underestimated by the JKR model, due to the appearance of plasticity in the grains, which shows up in the form of localized shear transformation zones. The JKR model strongly underestimates the contact radius and the collision duration during the outgoing trajectory, evidencing that the breaking of covalent bonds during grain separation is not well described by this model. The adhesive neck formed between the two grains finally collapses while creating narrow filaments joining the grains, which eventually tear.

On the Mechanism of the Iodide-Triiodide Exchange Reaction in a Solid-State Ionic Liquid

Grossi, J ;Kohanoff, JJ ; English, NJ ; Bringa, EM ; Del Popolo, MG ; JOURNAL OF PHYSICAL CHEMISTRY B ,2017 ,121 ,6436 -6441 .

Efficient charge transport has been observed in iodide-based room-temperature ionic liquids when doped with iodine. To investigate preferred pathways for the iodide (I-)-to-triiodide (I-3(-)) exchange reaction and to clarify the origin of this high ionic conductivity, we have conducted electronic structure calculations in the crystal state of 1-butyl-3methylimidazolium iodide ([BMIM] [I]). Energy barriers for the different stages of the iodine-swapping process, including the reorientation of the I-center dot center dot center dot I3- moiety, were determined from minimum energy paths as a function of a reaction coordinate. Hirshfeld charges and structural parameters, such as bond lengths and angles, were monitored during the reaction. Several bond exchange events were observed with energy barriers ranging from 0.17 to 0.48 eV and coinciding with the formation of a twisted I-center dot center dot center dot I-3(-) complex. Striking similarities were observed in the mechanics and energetics of this charge-transfer process in relation to solid-state superionic conductors.

BIO-HISTORY OF NOMADISM AND TERRITORIAL PRODUCTION IN NORTHEAST OF MENDOZA: INTERDISCIPLINARY READING FROM ECOLOGY, ARCHEOLOGY AND ETHNOGRAPHY

Katzer, L ;Zumbo, PG ; Chiavazza, H ; Gasull, VM ; Velez, S ; RELACIONES ,2017 ,42 ,345 -367 .

In the Latin American and Argentinean scientific imaginary, nomadic life forms lack current existence. However, the ethnographic records of Lavalle's dryland show the opposite. The following article proposes to analyze the social and cultural mechanisms through which the ethnic ascripts construct territoriality and structure their forms of sociability on the basis of a reactivated nomadism, based on an interdisciplinary reading from ecology, archeology and ethnography. We approach the territorial production in the NE of Mendoza in a multidimensional way proposing as a central hypothesis that native forms of sociability tend to activate and give continuity in a reconfigured and updated way, the historical forms of nomadism (archaeologically and ethno historically recorded) in these dimensions Work, residence and management of local natural resources.

PAINTED GUANACO BONES FROM CUEVA HUENUL 1 (NORTHERN NEUQUEN PROVINCE, NORTHERN PATAGONIA, ARGENTINA)

Romero, G ;Barberena, R ; RELACIONES ,2017 ,42 ,369 -377 .

Autoscaling Scientific Workflows on the Cloud by Combining On-demand and Spot Instances

Monge, DA ;Gari, Y ; Mateos, C ; Garino, CG ; COMPUTER SYSTEMS SCIENCE AND ENGINEERING ,2017 ,32 ,291 -306 .

Autoscaling strategies achieve efficient and cheap executions of scientific workflows running in the cloud by determining appropriate type and amount of virtual machine instances to use while scheduling the tasks/data. Current strategies only consider on-demand instances ignoring the advantages of a mixed cloud infrastructure comprising also spot instances. Although the latter type of instances are subject to failures and therefore provide an unreliable infrastructure, they potentially offer significant cost and time improvements if used wisely. This paper discusses a novel autoscaling strategy with two features. First, it combines both types of instances to acquire a better cost-performance balance in the infrastructure. And second, it uses heuristic scheduling to deal with the unreliability of spot instances. Simulated experiments based on 4 scientific workflows showed substantial makespan and cost reductions of our strategy when compared with a reference strategy from the state of the art entitled Scaling First. These promising results represent a step towards new and better strategies for workflow autoscaling in the cloud.

Effects of Urban Sprawl on Riparian Vegetation: Is Compact or Dispersed Urbanization Better for Biodiversity?

Guida-Johnson, B ;Faggi, AM ; Zuleta, GA ; RIVER RESEARCH AND APPLICATIONS ,2017 ,33 ,959 -969 .

Compact urbanization is the main strategy for sustainable urban development. However, it is yet unclear whether compact urban forms are ecologically more favourable than dispersed ones. In this paper, we studied the effects of urban sprawl on the riparian vegetation condition in one of the most degraded watersheds in the Buenos Aires metropolitan area, Argentina. We conducted random sampling of the riparian vegetation at sites along streams in the basin and assessed urban indicators at the reach and sub-watershed scales for each of those sites in a geographic information system: urban area, impervious surface, population density and two landscape metrics of dispersion. The indicators assessed explained a high proportion of the variability of the vegetation response variables, thereby confirming the importance of urban sprawl pressure in shaping riparian communities in fluvial ecosystems. Dispersed urbanization had more positive than negative effects on the vegetation in the study area. Riverbanks associated with dispersed urbanization had more plant species, including exotics, when urban sprawl was assessed at the local scale. At the sub-watershed scale, dispersed urbanized areas were richer in native plants and most of the functional groups, and poorer in exotic species. The model of the compact city, including bio-corridors along watercourses, has been proposed for the Buenos Aires conurbation process for the next decades. Our results showed that the quality of existing river corridors across the compact matrix was not desirable and best practices for redesigning a more sustainable landscape structure are necessary, including the restoration of habitats for wetland species. Copyright (c) 2017 John Wiley & Sons, Ltd.

Molecular Explanation for the Abnormal Flux of Material into a Hot Spot in Ester Monolayers

Galassi, VV ;Del Popolo, MG ; Fischer, TM ; Wilke, N ; JOURNAL OF PHYSICAL CHEMISTRY B ,2017 ,121 ,5621 -5632 .

Langmuir monolayers of certain surfactants show a negative derivative of the surface pressure with respect to temperature. In these monolayers, a local temperature gradient leads to local yielding of the solid phase to a kinetically flowing liquid, so that the material flows toward the hotter regions that act as sinks. The accumulation of material leads to the formation of nonequilibrium multilamellar bubbles of different sizes, Here we investigate the molecular factors leading to such a peculiar behavior. First, we identify the required structural molecular moieties, and second we vary the composition of the subphase in order to analyze its influence. We conclude that esters appear to be unique in two key aspects: they form monolayers whose compression isotherms shift to lower areas as the temperature increases, and thus collapse into a hot spot; and they bind weakly to the aqueous subphase, i.e., water does not attach to the monolayer at the molecular level, but only supports it. Molecular simulations for a selected system confirm and help explain the observed behavior: surfactant molecules form a weak hydrogen bonding network, which is disrupted upon heating, and also the molecular tilting changes with temperature, leading to changes in the film density.

Zooming out from archaeological discontinuities: The meaning of mid-Holocene temporal troughs in South American deserts

Barberena, R ;Mendez, C ; de Porras, ME ; JOURNAL OF ANTHROPOLOGICAL ARCHAEOLOGY ,2017 ,46 ,68 -81 .

Building on previous research at smaller scales, in this paper we assemble paleoecological data and archaeological time-series for deserts located in three latitudinal bands along the South American Arid Diagonal (16-41 S, 1,236,000 km(2) of area). Diverse proxies suggest the existence of arid and extremely arid conditions in large parts of these deserts. Working with a database composed of 914 archaeological dates falling between the first human presence in each region and 3000 years BP, which produce a minimum number of 578 occupational events, we identify a series of patterns at a macro-regional scale: a robust increase in the temporal signal at the beginning of the mid-Holocene (8000-7600 years BP) followed by two troughs (7600-7200, 6800-6400 years BP) during this period. The spatial scope of the data presented provides an opportunity for disentangling processes of spatial re-localization from actual changes in population size. We present a demographic hypothesis at a macro-regional scale, which suggests the existence of mid-Holocene population bottleneck(s). This hypothesis would account not only for the mid-Holocene troughs, but also for the posterior record of an intense and relatively rapid population growth (release) observed in many regions of the arid diagonal. These mid-Holocene events provide the context for independent trajectories of economic intensification based on different sets of resources marine foods, camelids, and also probably wetland resources-, some of which lead to domestication processes. These cases occur in association with a tendency towards reduced residential mobility in regions that may have acted as refugia during arid periods of the mid-Holocene.

Thiols of flagellar proteins are essential for progressive motility in human spermatozoa

Cabrillana, ME ;Monclus, MD ; Lancellotti, TES ; Boarelli, PV ; Vincenti, AE ; Fornes, MM ; Sanabria, EA ; Fornes, MW ; REPRODUCTION FERTILITY AND DEVELOPMENT ,2017 ,29 ,1435 -1446 .

Male infertility is a disorder of the reproductive system defined by the failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse. The presence of low-motile or immotile spermatozoa is one of many causes of infertility; however, this observation provides little or no information regarding the pathogenesis of the malfunction. Good sperm motility depends on correct assembly of the sperm tail in the testis and efficient maturation during epididymal transit. Thiols of flagellar proteins, such as outer dense fibre protein 1 (ODF1), are oxidised to form disulfides during epididymal transit and the spermatozoa become motile. This study was designed to determine how oxidative changes in protein thiol status affect progressive motility in human spermatozoa. Monobromobimane (mBBr) was used as a specific thiol marker and disruptor of sperm progressive motility. When mBBr was blocked by dithiothreitol it did not promote motility changes. The analysis of mBBr-treated spermatozoa revealed a reduction of progressive motility and an increased number of spermatozoa with non-progressive motility without affecting ATP production. Laser confocal microscopy and western blot analysis showed that one of the mBBr-positive proteins reacted with an antibody to ODF1. Monobromobimane fluorescence intensity of the sperm tail was lower in normozoospermic than asthenozoospermic men, suggesting that thiol oxidation in spermatozoa of asthenozoospermic men is incomplete. Our findings indicate that mBBr affects the thiol status of ODF1 in human spermatozoa and interferes with progressive motility.

Integrating Identities: An Innovative Bioarchaeological and Biogeochemical Approach to Analyzing the Multiplicity of Identities in the Mortuary Record Comment

Barberena, R ;CURRENT ANTHROPOLOGY ,2017 ,58 ,398 -399 .

Archaeological discontinuities in the southern hemisphere: A working agenda

Barberena, R ;McDonald, J ; Mitchell, PJ ; Veth, P ; JOURNAL OF ANTHROPOLOGICAL ARCHAEOLOGY ,2017 ,46 ,1 -11 .

This introductory overview presents the frame of research and general goals of the special volume "Archaeological Discontinuities: Comparative Frameworks for the southern hemisphere". We begin by deconstructing archaeological discontinuities in terms of time and space in order to assess what sort of past phenomena are we dealing with when assessing discontinuities in different scales. It is one of our main contentions that we need theory and data connecting discontinuities as recorded on different analytical scales, thereby contributing to evaluate often-undescribed mechanisms that produce archaeological discontinuities. On this basis, we face the key task of deconstructing archaeological discontinuities from 'top to bottom', moving from the averaged material record that is visible in archaeological scale toward the short-term human decisions and interactions that, when occurring cumulatively, produce those discontinuities. Nevertheless, while an understanding of the short-term behavioral mechanisms and social agency behind discontinuities is necessary, it is certainly not sufficient for building a frame in which to make sense of the long-term record.

Obsidian geochemistry, geoarchaeology, and lithic technology in northwestern Patagonia (Argentina)

Fernandez, MV ;Barberena, R ; Rughini, AA ; Giesso, M ; Cortegoso, V ; Duran, V ; Villanueva, GR ; Borrazzo, K ; Lucero, G ; Garvey, R ; MacDonald, BL ; Glascock, MD ; JOURNAL OF ARCHAEOLOGICAL SCIENCE-REPORTS ,2017 ,13 ,372 -381 .

We studied the organization of mobility of hunter-gatherers groups of northwestern Patagonia (Argentina) from an interdisciplinary perspective. We combined geochemical and technological characterization of obsidian assemblages from surface and stratigraphic contexts spanning the Holocene, and a preliminary geoarchaeological study of the sources. The goals were to assess the provenance, mode of supply, use, and discard of obsidian artifacts on the basis of information on the structure of the two main regional sources: Cerro Huenul, located in the lowlands, and Laguna del Maule, located in the Andean highlands. We conducted geoarchaeological field sampling at different altitudes of the Barrancas River fluvial deposits to study the geomorphic impact on the secondary structure of the highland source. Preliminary geoarchaeological results allow extending the area of availability up to 90 km towards the lowlands from the outcrops. In addition, we performed non-destructive XRF analyses on 266 lithic artifacts, which were placed along a continuum of reduction. 89% of the artifacts corresponded to the local Cerro Huenul source, while 11% to Laguna del Maule. While the artifacts made on Cerro Huenul obsidian were represented by the full reduction sequence, those from Laguna del Maule are only represented by advanced stages. We integrate these results with information on the frequencies of projectile points, ceramics, and rock-art motifs for the two main archaeological sites in the region: Cueva Huenul 1 and Cueva Yagui. These proxies indicate that the sites have different place use histories, providing a scheme for the analysis of human use of the regional landscape.

Salinization in irrigated drylands: prospects for restoration in Cuyo, Argentina

Guida-Johnson, B ;Abraham, EM ; Cony, MA ; REVISTA DE LA FACULTAD DE CIENCIAS AGRARIAS ,2017 ,49 ,205 -215 .

Drylands are characterized among other things by low rainfall and soils with insufficient water. In these regions, agricultural production depends on irrigation, which transforms arid ecosystems into irrigated arableareas, as in the Cuyo region, in the central-western Argentina. Although these lands support the majority of the population, they are often associated with degradation processes. One of the main consequences of unsustainable agriculture is soil salinization, which occurs either because perennial deep-rooted native vegetation is replaced by annual crops or as a result of excessive irrigation and deficient drainage. Salinization is a global problem, since it reduces the productivity of large arable areas, decreases land value and leads to their abandonment. In this context, ecosystem restoration is a strategic approach to reverse the degradation of irrigated drylands, recover services and promote the conservation of arid ecosystems at the regional scale. In this paper we review the factors, both those linked to the biophysical environment and those determined by human activities, which are associated with salinization in different regions, as well as the implemented measures for rehabilitating these environments. Furthermore, the terminology associated with the practice of restoration is revised and a suitable alternative for exploring this approach in Cuyo is proposed: the productive restoration using species of the Prosopis genus.

Behavioural flexibility does not prevent numerical declines of harvester ants under intense livestock grazing

Pol, RG ;Vargas, GA ; Marone, L ; ECOLOGICAL ENTOMOLOGY ,2017 ,42 ,283 -293 .

1. Human-induced rapid environmental change may decrease food resources and create unfavourable conditions for native species. Organisms showing a flexible foraging behaviour can exploit novel or alternative foods and are more likely to persist, whereas less flexible organisms might suffer starvation and numerical reductions. 2. This study assessed whether declines in the quality and availability of seeds prompted by grazing provoke behavioural and numerical responses in Pogonomyrmex mendozanus ants, and aimed to test whether behavioural flexibility buffers habitat degradation and prevents numerical declines. 3. Heavy grazing caused seed reductions, especially of the highly consumed and preferred grass seeds, and triggered two kinds of ant responses. Ants expanded their diet by incorporating a greater proportion of non-seed items, and they reduced foraging activity. As a consequence, the rate of food intake per colony lessened, particularly that of carbohydrate-rich seeds like grass seeds. Colony density under heavy grazing also fell. 4. Habitat degradation triggered a cascade of mechanisms that starts with a decrease in the seed resources and continues with changes in ant behaviour. However, behavioural responses were insufficient to prevent ant numerical declines. The results of this study suggest that the reduction in the colony density under habitat degradation was provoked by ant nutritional deficit and starvation, and predict a deterioration in body condition, colony performance and reproduction of ants, which deserve further assessment.

Autonomous learning by simple dynamical systems with a discrete-time formulation

Bilen, AM ;Kaluza, P ; EUROPEAN PHYSICAL JOURNAL B ,2017 ,90 ,-.

We present a discrete-time formulation for the autonomous learning conjecture. The main feature of this formulation is the possibility to apply the autonomous learning scheme to systems in which the errors with respect to target functions are not well-defined for all times. This restriction for the evaluation of functionality is a typical feature in systems that need a finite time interval to process a unit piece of information. We illustrate its application on an artificial neural network with feed-forward architecture for classification and a phase oscillator system with synchronization properties. The main characteristics of the discrete-time formulation are shown by constructing these systems with predefined functions.

Galectin-1 expression imprints a neurovascular phenotype in proliferative retinopathies and delineates responses to anti-VEGF

Ridano, ME ;Subirada, PV ; Paz, MC ; Lorenc, VE ; Stupirski, JC ; Gramajo, AL ; Luna, JD ; Croci, DO ; Rabinovich, GA ; Sanchez, MC ; ONCOTARGET ,2017 ,8 ,32505 -32522 .

Neovascular retinopathies are leading causes of irreversible blindness. Although vascular endothelial growth factor (VEGF) inhibitors have been established as the mainstay of current treatment, clinical management of these diseases is still limited. As retinal impairment involves abnormal neovascularization and neuronal degeneration, we evaluated here the involvement of galectin-1 in vascular and non-vascular alterations associated with retinopathies, using the oxygen-induced retinopathy (OIR) model. Postnatal day 17 OIR mouse retinas showed the highest neovascular profile and exhibited neuro-glial injury as well as retinal functional loss, which persisted until P26 OIR. Concomitant to VEGF up-regulation, galectin-1 was highly expressed in P17 OIR retinas and it was mainly localized in neovascular tufts. In addition, OIR induced remodelling of cell surface glycophenotype leading to exposure of galectin-1-specific glycan epitopes. Whereas VEGF returned to baseline levels at P26, increased galectin-1 expression persisted until this time period. Remarkably, although anti-VEGF treatment in P17 OIR improved retinal vascularization,neithergalectin-1 expression nor non-vascular and functional alterations were attenuated. However, this functional defect was partially prevented in galectin-1-deficient (Lgals1(-/-)) OIR mice, suggesting the importance of targeting both VEGF and galectin-1 as non-redundant independent pathways. Supporting the clinical relevance of these findings, we found increased levels of galectin-1 in aqueous humor from patients with proliferative diabetic retinopathy and neovascular glaucoma. Thus, using an OIR model and human samples, we identified a role for galectin-1 accompanying vascular and non-vascular retinal alterations in neovascular retinopathies.

Coevolution of functional flow processing networks

Kaluza, P ;EUROPEAN PHYSICAL JOURNAL B ,2017 ,90 ,-.

We present a study about the construction of functional flow processing networks that produce prescribed output patterns (target functions). The constructions are performed with a process of mutations and selections by an annealing-like algorithm. We consider the coevolution of the prescribed target functions during the optimization processes. We propose three different paths for these coevolutions in order to evolve from a simple initial function to a more complex final one. We compute several network properties during the optimizations by using the different path-coevolutions as mean values over network ensembles. As a function of the number of iterations of the optimization we find a similar behavior like a phase transition in the network structures. This result can be seen clearly in the mean motif distributions of the constructed networks. Coevolution allows to identify that feed-forward loops are responsible for the development of the temporal response of these systems. Finally, we observe that with a large number of iterations the optimized networks present similar properties despite the path-coevolution we employed.

Synthesis of Lithium Fluoride from Spent Lithium Ion Batteries

Suarez, DS ;Pinna, EG ; Rosales, GD ; Rodriguez, MH ; MINERALS ,2017 ,7 ,-.

Lithium (Li) is considered a strategic element whose use has significantly expanded. Its current high demand is due to its use in lithium ion batteries for portable electronic devices, whose manufacture and market are extensively growing every day. These days there is a great concern about the final disposal of these batteries. Therefore, the possibility of developing new methodologies to recycle their components is of great importance, both commercially and environmentally. This paper presents results regarding important operational variables for the dissolution of the lithium and cobalt mixed-oxide (LiCoO2) cathodes from spent lithium ion batteries (LIBs) with hydrofluoric acid. The recovery and synthesis of Co and Li compounds were also investigated. The dissolution parameters studied were: temperature, reaction time, solid-liquid ratio, stirring speed, and concentration of HF. The investigated recovery parameters included: pH, temperature, and time with and without stirring. The final precipitation of lithium fluoride was also examined. The results indicate that an increase in the HF concentration, temperature, and reaction time favors the leaching reaction of the LiCoO2. Dissolutions were close to 60%, at 75 degrees C and 120 min with a HF concentration of 25% (v/v). The recovery of Co and Li were 98% and 80%, respectively, with purities higher than 94%. Co and Li compounds, such as Co3O4 and LiF, were synthesized. Furthermore, it was possible to almost completely eliminate the F- ions as CaF2.

Livestock Settlement Dynamics in Drylands: Model application in the Monte desert (Mendoza, Argentina)

Millan, EN ;Goiran, S ; Aranibar, JN ; Bringa, EM ; ECOLOGICAL INFORMATICS ,2017 ,39 ,84 -98 .

Human settlements in arid environments are becoming widespread due to population growth, and without planning, they may alter vegetation and ecosystem processes, compromising sustainability. We hypothesize that in an arid region of the central Monte desert (Mendoza, Argentina), surface and groundwater availability are the primary factors controlling livestock settlements establishment and success as productive units, which affect patterns of degradation in the landscape. To evaluate this hypothesis we simulated settlement dynamics using a Monte Carlo based model of Settlement Dynamics in Drylands (SeDD), which calculates probabilities on a gridded region based on six environmental factors: groundwater depth, vegetation type, proximity to rivers, paved road, old river beds, and existing settlements. A parameter sweep, including millions of simulations, was run to identify the most relevant factors controlling settlements. Results indicate that distances to rivers and the presence of old river beds are critical to explain the current distribution of settlements, while vegetation, paved roads, and water table depth were not as relevant to explain settlement distribution. Far from surface water sources, most settlements were established at random, suggesting that pressures to settle in unfavorable places control settlement dynamics in those isolated areas. The simulated vegetation, which considers degradation around livestock settlements, generally matched the spatial distribution of remotely sensed vegetation classes, although with a higher cover of extreme vegetation classes. The model could be a useful tool to evaluate effects of land use changes, such as water provision or changes on river flows, on settlement distribution and vegetation degradation in arid environments. (C) 2017 Elsevier B.V. All rights reserved.

Coprecipitation-assisted coacervative extraction coupled to high-performance liquid chromatography: An approach for determining organophosphorus pesticides in water samples

Mammana, SB ;Berton, P ; Camargo, AB ; Lascalea, GE ; Altamirano, JC ; ELECTROPHORESIS ,2017 ,38 ,1334 -1343 .

An analytical methodology based on coprecipitation-assisted coacervative extraction coupled to HPLC-UV was developed for determination of five organophosphorus pesticides (OPPs), including fenitrothion, guthion, parathion, methidathion, and chlorpyrifos, in water samples. It involves a green technique leading to an efficient and simple analytical methodology suitable for high-throughput analysis. Relevant physicochemical variables were studied and optimized on the analytical response of each OPP. Under optimized conditions, the resulting methodology was as follows: an aliquot of 9 mL of water sample was placed into a centrifuge tube and 0.5 mL sodium citrate 0.1 M, pH 4; 0.08 mL Al-2(SO4)(3) 0.1 M; and 0.7 mL SDS 0.1 M were added and homogenized. After centrifugation the supernatant was discarded. A 700 L aliquot of the coacervate-rich phase obtained was dissolved with 300 L of methanol and 20 L of the resulting solution was analyzed by HPLC-UV. The resulting LODs ranged within 0.7-2.5 ng/mL and the achieved RSD and recovery values were <8% (n = 3) and >81%, respectively. The proposed analytical methodology was successfully applied for the analysis of five OPPs in water samples for human consumption of different locations of Mendoza.

Evidence for a prokaryotic origin of intracellular corpuscles in the digestive gland of the queen conch Lobatus gigas (Linnaeus, 1758) (Gastropoda: Strombidae)

Dellagnola, FA ;Vega, IA ; Castro-Vazquez, A ; JOURNAL OF MOLLUSCAN STUDIES ,2017 ,83 ,186 -193 .

Two types of pigmented intracellular bodies have been reported in the digestive glands of several caenogastropods, particularly in the families Ampullariidae (Architaenioglossa: Ampullarioidea), Strombidae and Struthiolariidae (Littorinimorpha: Stromboidea). Rounded corpuscles, which are usually light brown, are identified here as C corpuscles, while corpuscles that are oval, darker and larger are identified as K corpuscles. We studied both corpuscular types in Lobatus gigas (Strombidae) using (1) differential-interference contrast microscopy, (2) transmission electron microscopy, (3) in situ hybridization with a generalized cyanobacterial 16S rRNA probe and (4) autofluorescence before and after lysozyme digestion. Results indicated that C corpuscles were located in the basal regions of columnar cells and the intensity of their pigmentation and alcianophily (indicative of glycosaminoglycans) was variable. They showed an electron-dense wall and contained abundant electron-dense clumps and irregularly arranged membranes, but no thylakoids or nuclei. Hybridization with the 16S rRNA probe varied from none to intense in C corpuscles, indicative of variations in the rRNA content during their life cycles. Their walls were sensitive to lysozyme digestion, which strongly suggests that peptidoglycans are an integral part of this structure. K corpuscles were located within pyramidal cells and were uniformly dark brown but variably alcianophilic. They showed multiple lamellae of moderate electron density, organized around one to three cores, each one containing one or several small spherical bodies. All K corpuscles hybridized with the 16S rRNA probe and were partly digested by lysozyme. Both C and K corpuscles showed red autofluorescence, which suggests the presence of chlorophyll-like pigments. It is concluded that C and K corpuscles in the digestive gland of L. gigas may be forms of a prokaryotic symbiont related to the Cyanobacteria.

Understanding the ion-induced elongation of silver nanoparticles embedded in silica

Pena-Rodriguez, O ;Prada, A ; Olivares, J ; Oliver, A ; Rodriguez-Fernandez, L ; Silva-Pereyra, HG ; Bringa, E ; Perlado, JM ; Rivera, A ; SCIENTIFIC REPORTS ,2017 ,7 ,-.

In this work we have studied the elongation of silver nanoparticles irradiated with 40 MeV Bromine ions by means of in situ optical measurements, transmission electron microscopy and molecular dynamics simulations. The localized surface plasmon resonance of silver nanoparticles has a strong dependence on the particle shape and size, which allowed us to obtain the geometrical parameters with remarkable accuracy by means of a fit of the optical spectra. Optical results have been compared with transmission electron microscopy images and molecular dynamics simulations and the agreement is excellent in both cases. An important advantage of in situ measurements is that they yield an extremely detailed information of the full elongation kinetics. Final nanoparticle elongation depends on a complex competition between single-ion deformation, Ostwald ripening and dissolution. Building and validating theoretical models with the data reported in this work should be easier than with the information previously available, due to the unprecedented level of kinetic details obtained from the in situ measurements.

On the role of residue phosphorylation in 14-3-3 partners: AANAT as a case study

Masone, D ;Uhart, M ; Bustos, DM ; SCIENTIFIC REPORTS ,2017 ,7 ,-.

Twenty years ago, a novel concept in protein structural biology was discovered: the intrinsically disordered regions (IDRs). These regions remain largely unstructured under native conditions and the more are studied, more properties are attributed to them. Possibly, one of the most important is their ability to conform a new type of protein-protein interaction. Besides the classical domain-todomain interactions, IDRs follow a 'fly-casting' model including 'induced folding'. Unfortunately, it is only possible to experimentally explore initial and final states. However, the complete movie of conformational changes of protein regions and their characterization can be addressed by in silico experiments. Here, we simulate the binding of two proteins to describe how the phosphorylation of a single residue modulates the entire process. 14-3-3 protein family is considered a master regulator of phosphorylated proteins and from a modern point-of-view, protein phosphorylation is a three component system, with writers (kinases), erasers (phosphatases) and readers. This later biological role is attributed to the 14-3-3 protein family. Our molecular dynamics results show that phosphorylation of the key residue Thr31 in a partner of 14-3-3, the aralkylamine N-acetyltransferase, releases the flycasting mechanism during binding. On the other hand, the non-phosphorylation of the same residue traps the proteins, systematically and repeatedly driving the simulations into wrong protein-protein conformations.

Ionic and stable isotope chemistry as indicators of water sources to the Upper Mendoza River basin, Central Andes of Argentina

Crespo, S ;Aranibar, J ; Gomez, L ; Schwikowski, M ; Bruetsch, S ; Cara, L ; Villalba, R ; HYDROLOGICAL SCIENCES JOURNAL-JOURNAL DES SCIENCES HYDROLOGIQUES ,2017 ,62 ,588 -605 .

The Mendoza River is mainly dependent on the melting of snow and ice in the Upper Andes. Since predicted changes in climate would modify snow accumulation and glacial melting, it is important to understand the relative contributions of various water sources to river discharge. The two main mountain ranges in the basin, Cordillera Principal and Cordillera Frontal, present differences in geology and receive differing proportions of precipitation from Atlantic and Pacific moisture sources. We propose that differences in the origin of precipitation, geology and sediment contact times across the basin generate ionic and stable isotopic signatures in the water, allowing the differentiation of water sources. Waters from the Cordillera Principal had higher salinity and were more isotopically depleted than those from the Cordillera Frontal. Stable isotope composition and salinity differed among different water sources. The chemical temporal evolution of rivers and streams indicated changes in the relative contributions of different sources, pointing to the importance of glacier melting and groundwater in the river discharge.

Unparalleled replacement of native mitochondrial genes by foreign homologs in a holoparasitic plant

Sanchez-Puerta, MV ;Garcia, LE ; Wohlfeiler, J ; Ceriotti, LF ; NEW PHYTOLOGIST ,2017 ,214 ,376 -387 .

Horizontal gene transfer (HGT) among flowering plant mitochondria occurs frequently and, in most cases, leads to nonfunctional transgenes in the recipient genome. Parasitic plants are particularly prone to this phenomenon, but their mitochondrial genomes (mtDNA) have been largely unexplored.

Translating the 'Sugar Code' into Immune and Vascular Signaling Programs

Cerliani, JP ;Blidner, AG ; Toscano, MA ; Croci, DO ; Rabinovich, GA ; TRENDS IN BIOCHEMICAL SCIENCES ,2017 ,42 ,255 -273 .

The vast range and complexity of glycan structures and their dynamic variations in health and disease have presented formidable challenges toward understanding the biological significance of these molecules. Despite these limitations, compelling evidence highlights a major role for galectins, a family of soluble glycan-binding proteins, as endogenous decoders that translate glycan-containing information into a broad spectrum of cellular responses by modulating receptor clustering, reorganization, endocytosis, and signaling. Here, we underscore pioneer findings and recent advances in understanding the biology of galectin-glycan interactions in myeloid, lymphoid, and endothelial compartments, highlighting important pathways by which these multivalent complexes control immune and vascular programs. Implementation of novel glycoanalytical approaches, as well as the use of genetically engineered cell and organism models, have allowed glycans and galectins to be explored across a range of cellular processes.

Cooked garlic and antioxidant activity: Correlation with organosulfur compound composition

Locatelli, DA ;Nazareno, MA ; Fusari, CM ; Camargo, AB ; FOOD CHEMISTRY ,2017 ,220 ,219 -224 .

The antioxidant properties and the main beneficial organosulphur compounds of home-cooked garlic samples were studied in order to establish relationships between them. Antioxidant activity was tested by free radical scavenging against 2,2-diphenyl-1-picrylhydrazyl radical (DPPH center dot) and 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS(+center dot)), Fe(III) reducing ability (FRAP) and linoleic acid co-oxidation initiated by soybean lipoxygenase in a micelle system. DPPH, ABTS and FRAP assays showed the highest activity for raw garlic samples, while beta-carotene bleaching assay yielded the highest activity for stir-fried garlic. Pure organosulphur compounds tested by DPPH, FRAP and beta-carotene bleaching assays showed that allicin had an antiradical action mechanism, as well as iron reducing capacity; while antioxidant activity was the main mechanism for ajoenes and 2-VD. To our knowledge, this study is the first demonstration that home-cooked garlic retains its antioxidant activity, and, at the same time, elucidates the mechanisms involved in this activity. (C) 2016 Elsevier Ltd. All rights reserved.

Ionic liquid-assisted separation and determination of selenium species in food and beverage samples by liquid chromatography coupled to hydride generation atomic fluorescence spectrometry

Grijalba, AC ;Fiorentini, EF ; Wuilloud, RG ; JOURNAL OF CHROMATOGRAPHY A ,2017 ,1491 ,117 -125 .

Different ionic liquids (ILs) were assayed as mobile phase modifiers for the separation and determination of selenite [Se(IV)1, selenate [Se(VI)], selenomethionine (SeMet) and Se-methylselenocysteine (SeMeSeCys) by reversed-phase high-performance liquid chromatography coupled to hydride generation atomic fluorescence spectrometry (RP-HPLC-HG-AFS). The use of several ILs: 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride ([C(6)mirn]Cl), 1-octy1-3-methylimidazolium chloride, 1-dodecyl-3-methylimidazolium bromide, 1-hexadecy1-3-methylimidazolium bromide and tributyl(methyl)phosphonium methylsulphate was evaluated. Also, the effect of pH, buffer type and IL concentration on the separation of Se species was studied. Complete separation was attained within 12 min using a C-8 column and a gradient performed with a mobile phase containing 0.1% (v/v) [C(6)mim]Cl at pH 6.0. The proposed method allows the separation of inorganic and organic Se species in a single chromatographic run, adding further benefits over already reported methods based on RP-HPLC. In addition, the influence of ILs on the AFS signals of each Se species was evaluated and a multivariate methodology was used for optimization of AFS sensitivity. The limits of detection were 0.92, 0.86,1.41 and 1.19 mu gL(-1) for Se(IV), Se(VI), SeMet and SeMeSeCys, respectively. The method was successfully applied for speciation analysis of Se in complex samples, such as wine, beer, yeast and garlic. (C) 2017 Elsevier B.V. All rights reserved.

Inorganic selenium speciation analysis in Allium and Brassica vegetables by ionic liquid assisted liquid-liquid microextraction with multivariate optimization

Grijalba, AC ;Martinis, EM ; Wuilloud, RG ; FOOD CHEMISTRY ,2017 ,219 ,102 -108 .

A highly sensitive vortex assisted liquid-liquid microextraction (VA-LLME) method was developed for inorganic Se [Se(IV) and Se(VI)] speciation analysis in Allium and Brassica vegetables. Trihexyl(tetrade cyl)phosphonium decanoate phosphonium ionic liquid (IL) was applied for the extraction of Se(IV)ammonium pyrrolidine dithiocarbamate (APDC) complex followed by Se determination with electrothermal atomic absorption spectrometry. A complete optimization of the graphite furnace temperature program was developed for accurate determination of Se in the IL-enriched extracts and multivariate statistical optimization was performed to define the conditions for the highest extraction efficiency. Significant factors of IL-VA-LLME method were sample volume, extraction pH, extraction time and APDC concentration. High extraction efficiency (90%), a 100-fold preconcentration factor and a detection limit of 5.0 ng/L were achieved. The high sensitivity obtained with preconcentration and the non-chromatographic separation of inorganic Se species in complex matrix samples such as garlic, onion, leek, broccoli and cauliflower, are the main advantages of IL-VA-LLME. (C) 2016 Elsevier Ltd. All rights reserved.

On the static Casimir effect with parity-breaking mirrors

Fosco, CD ;Remaggi, ML ; EUROPEAN PHYSICAL JOURNAL C ,2017 ,77 ,-.

We study the Casimir interaction energy due to the vacuum fluctuations of the electromagnetic (EM) field in the presence of two mirrors, described by 2 + 1-dimensional, generally nonlocal actions, which may contain both parity-conserving and parity-breaking terms. We compare the results with the ones corresponding to Chern-Simons boundary conditions and evaluate the interaction energy for several particular situations.

Foreign Plastid Sequences in Plant Mitochondria are Frequently Acquired Via Mitochondrion-to-Mitochondrion Horizontal Transfer

Gandini, CL ;Sanchez-Puerta, MV ; SCIENTIFIC REPORTS ,2017 ,7 ,-.

Angiosperm mitochondrial genomes (mtDNA) exhibit variable quantities of alien sequences. Many of these sequences are acquired by intracellular gene transfer (IGT) from the plastid. In addition, frequent events of horizontal gene transfer (HGT) between mitochondria of different species also contribute to their expanded genomes. In contrast, alien sequences are rarely found in plastid genomes. Most of the plant-to-plant HGT events involve mitochondrion-to-mitochondrion transfers. Occasionally, foreign sequences in mtDNAs are plastid-derived (MTPT), raising questions about their origin, frequency, and mechanism of transfer. The rising number of complete mtDNAs allowed us to address these questions. We identified 15 new foreign MTPTs, increasing significantly the number of those previously reported. One out of five of the angiosperm species analyzed contained at least one foreign MTPT, suggesting a remarkable frequency of HGT among plants. By analyzing the flanking regions of the foreign MTPTs, we found strong evidence for mt-to-mt transfers in 65% of the cases. We hypothesize that plastid sequences were initially acquired by the native mtDNA via IGT and then transferred to a distantly-related plant via mitochondrial HGT, rather than directly from a foreign plastid to the mitochondrial genome. Finally, we describe three novel putative cases of mitochondrial-derived sequences among angiosperm plastomes.

Recovery Process of Li, Al and Si from Lepidolite by Leaching with HF

Rosales, GD ;Pinna, EG ; Suarez, DS ; Rodriguez, MH ; MINERALS ,2017 ,7 ,-.

This work describes the development of a new process for the recovery of Li, Al and Si along with the proposal of a flow sheet for the precipitation of those metals. The developed process is comprised of lepidolite acid digestion with hydrofluoric acid, and the subsequent precipitation of the metals present in the leach liquor. The leaching operational parameters studied were: reaction time, temperature and HF concentration. The experimental results indicate that the optimal conditions to achieve a Li extraction higher than 90% were: solid-liquid ratio, 1.82% (w/v); temperature, 123 degrees C; HF concentration, 7% (v/v); stirring speed, 330 rpm; and reaction time, 120 min. Al and Si can be recovered as Na3AlF6 and K2SiF6. LiF was separated from the leach liquor during water evaporation, with recovery values of 92%.

Simulations of cratering and sputtering from an ion track in crystalline and amorphous Lennard Jones thin films

Gutierres, LI ;Lima, NW ; Thomaz, RS ; Papaleo, RM ; Bringa, EM ; COMPUTATIONAL MATERIALS SCIENCE ,2017 ,129 ,98 -106 .

Impacts of swift heavy ions of different energy loss in amorphous and crystalline Lennard-Jones (L.) thin films (2-60 nm) were simulated using classical molecular dynamics to study cratering and sputtering in model molecular thin films. Crater size is determined mostly by evaporation and melt flow from the hot ion track, while rim size is determined both by melt flow and by coherent displacement of particles due to the large pressure developed in the excited region, with minor influence of particles from the substrate. Sputtering yields from both crystalline and amorphous samples are similar (including the scaling with energy loss), due to the extremely high temperature and disordered condition of the track region from where most ejected particles originate in the early stages of the track evolution. Cratering, however clearly depends on the crystallinity of the film. Craters and rims are much smaller in crystalline films mainly due to faster energy dissipation, higher stress threshold for plasticity and smaller free-volume in the ordered phase. We also found a large dependence of the induced surface effects on film thickness below a critical thickness value. The pressure pulse due to the ion impact is weaker and cooling of the excited track is more efficient in short tracks, both contributing to the decreased radiation damage efficiency on ultrathin layers. Despite the simplicity of the LJ model, the simulations in the amorphous films reproduce remarkably well several of the experimental features seen recently on polymer thin and ultra thin films irradiated by swift heavy ions. (C) 2016 Elsevier B.V. All rights reserved.

Exotic plants promote pollination niche overlap in an agroecosystem

Marrero, HJ ;Torretta, JP ; Vazquez, DP ; Hodara, K ; Medan, D ; AGRICULTURE ECOSYSTEMS & ENVIRONMENT ,2017 ,239 ,304 -309 .

Agricultural land management modifies ecosystem structure and functioning in natural landscapes. Pollinators are a key functional group that may suffer from such intensification. Here we evaluate how agricultural land management influences the diversity of pollen transported by pollinators and the pollination niche overlap among plants. We described pollen transport networks (which allow assessing the contribution of pollinators to the flow of pollen among plants) in agricultural and restored fragments in three sites representative of the pampas region of Argentina. We analyzed diversity of pollen transported by pollinators and the pollination niche overlap among plants in both types of fragments with general and generalized linear mixed models. The agricultural fragments were associated to increased diversity of transported pollen and pollination niche overlap among plants. Greater pollination niche overlap in agricultural fragments was associated with increased abundance of exotic plants. Our results indicate that agricultural intensification has significantly increased the diversity of pollen and the pollination niche overlap in natural communities by promoting exotic plants and generalized plant pollinator interactions. Strategies to encourage improvements in the quality of pollination in agroecosystems could range from controlling the levels of exotic species to mechanisms that promote increased diversity of native plants. (C) 2017 Elsevier B.V. All rights reserved.

Defect production in Ar irradiated graphene membranes under different initial applied strains

Martinez-Asencio, J ;Ruestes, CJ ; Bringa, E ; Caturla, MJ ; NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM ,2017 ,393 ,44 -48 .

Irradiation with low energy Ar ions of graphene membranes gives rise to changes in the mechanical properties of this material. These changes have been associated to the production of defects, mostly isolated vacancies. However, the initial state of the graphene membrane can also affect its mechanical response. Using molecular dynamics simulations we have studied defect production in graphene membranes irradiated with 140 eV Ar ions up to a dose of 0.075 x 10(14) ions/cm(2) and different initial strains, from 0.25% (compressive strain) to 0.25% (tensile strain). For all strains, the number of defects increases linearly with dose with a defect production of about 80% (80 defects every 100 ions). Defects are mostly single vacancies and di-vacancies, although some higher order clusters are also observed. Two different types of di-vacancies have been identified, the most common one being two vacancies at first nearest neighbours distance. Differences in the total number of defects with the applied strain are observed which is related to the production of a higher number of di-vacancies under compressive strain compared to tensile strain. We attribute this effect to the larger out-of-plane deformations of compressed samples that could favor the production of defects in closer proximity to others. (C) 2016 Elsevier B.V. All rights reserved.

Effect of hyperthyroidism on circulating prolactin and hypothalamic expression of tyrosine hydroxylase, prolactin signaling cascade members and estrogen and progesterone receptors during late pregnancy and lactation in the rat

Pennacchio, GE ;Neira, FJ ; Soaje, M ; Jahn, GA ; Valdez, SR ; MOLECULAR AND CELLULAR ENDOCRINOLOGY ,2017 ,442 ,40 -50 .

Hyperthyroidism (HyperT) compromises pregnancy and lactation, hindering suckling-induced PRL release. We studied the effect of HyperT on hypothalamic mRNA (RT-qPCR) and protein (Western blot) expression of tyrosine hydroxylase (TH), PRL receptor (PRLR) and signaling pathway members, estrogen-alpha (ER alpha) and progesterone (PR) receptors on late pregnancy (days G19, 20 and 21) and early lactation (L2) in rats. HyperT advanced pre-partum PRL release, reduced circulating PRL on L2 and increased TH mRNA (G21 and L2), p-TH, PRLR mRNA, STAT5 protein (G19 and L2), PRLR protein (G21) and CIS protein (G19). PRs mRNAs and protein decreased on G19 but afterwards PRA mRNA (G20), PRB mRNA (G21) and PRA mRNA and protein (L2) increased. ER alpha protein increased on G19 and decreased on G20. Thus, the altered hypothalamic PRLR, STAT5, PR and ER alpha expression in hyperthyroid rats may induce elevated TH expression and activation, that consequently, elevate dopaminergic tone during lactation, blunting suckling-induced PRL release and litter growth. (C) 2016 Elsevier Ireland Ltd. All rights reserved.

A new spectral sequence for homology of posets

Cianci, N ;Ottina, M ; TOPOLOGY AND ITS APPLICATIONS ,2017 ,217 ,1 -19 .

We develop a new method to compute the homology groups of Alexandroff topological spaces (or equivalently of partially ordered sets) by means of spectral sequences giving a complete and simple description of the corresponding differentials. Applying our tools, we obtain a generalization of a result of Minian in homological Morse theory for posets. (C) 2016 Elsevier B.V. All rights reserved.

Impact of biogenic very short-lived bromine on the Antarctic ozone hole during the 21st century

Fernandez, RP ;Kinnison, DE ; Lamarque, JF ; Tilmes, S ; Saiz-Lopez, A ; ATMOSPHERIC CHEMISTRY AND PHYSICS ,2017 ,17 ,1673 -1688 .

Active bromine released from the photochemical decomposition of biogenic very short-lived bromocarbons (VSLBr) enhances stratospheric ozone depletion. Based on a dual set of 1960-2100 coupled chemistry-climate simulations (i.e. with and without VSLBr), we show that the maximum Antarctic ozone hole depletion increases by up to 14% when natural VSLBr are considered, which is in better agreement with ozone observations. The impact of the additional 5 pptv VSLBr on Antarctic ozone is most evident in the periphery of the ozone hole, producing an expansion of the ozone hole area of similar to 5 million km(2), which is equivalent in magnitude to the recently estimated Antarctic ozone healing due to the implementation of the Montreal Protocol. We find that the inclusion of VSLBr in CAM-Chem (Community Atmosphere Model with Chemistry, version 4.0) does not introduce a significant delay of the modelled ozone return date to 1980 October levels, but instead affects the depth and duration of the simulated ozone hole. Our analysis further shows that total bromine-catalysed ozone destruction in the lower stratosphere surpasses that of chlorine by the year 2070 and indicates that natural VSLBr chemistry would dominate Antarctic ozone seasonality before the end of the 21st century. This work suggests a large influence of biogenic bromine on the future Antarctic ozone layer.

DATING THE EXPANSION OF THE INCA EMPIRE: BAYESIAN MODELS FROM ECUADOR AND ARGENTINA

Marsh, EJ ;Kidd, R ; Ogburn, D ; Duran, V ; RADIOCARBON ,2017 ,59 ,117 -140 .

The chronology of the Inca Empire has traditionally relied on ethnohistoric dates, which suggest that a northern expansion into modern Ecuador began in AD 1463 and a southern expansion into modern Argentina began in AD 1471. We test the validity of these dates with two Bayesian models, which show that the ethnohistoric dates are incorrect and that the southern expansion began before the northern one. The first model of seven dates shows that the site of Chamical, Ecuador, was first occupied cal AD 1410-1480 (95% probability) and has a high probability of being built prior to the ethnohistoric date. The second is an outlier model of 26 C-14 dates and 19 thermoluminescence (TL) dates from 10 sites along the empire's southeastern limit in northwestern Mendoza, Argentina. Here, the Inca occupation began cal AD 1350-1440 (95% probability), also earlier than the ethnohistoric date. The model also suggests that the Inca occupation of Mendoza lasted 70-230 yr (95% probability), longer than previously thought, which calls for new perspectives on the timing and nature of Inca conquests and relationships with local groups. Based on these results, we argue it is time to abandon the traditional chronology in favor of Inca chronologies based on Bayesian models.

Learning network representations

Moyano, LG ;EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS ,2017 ,226 ,499 -518 .

In this review I present several representation learning methods, and discuss the latest advancements with emphasis in applications to network science. Representation learning is a set of techniques that has the goal of efficiently mapping data structures into convenient latent spaces. Either for dimensionality reduction or for gaining semantic content, this type of feature embeddings has demonstrated to be useful, for example, for node classification or link prediction tasks, among many other relevant applications to networks. I provide a description of the state-of-the-art of network representation learning as well as a detailed account of the connections with other fields of study such as continuous word embeddings and deep learning architectures. Finally, I provide a broad view of several applications of these techniques to networks in various domains.

Potential contribution to the invasion process of different reproductive strategies of two invasive roses

Mazzolari, AC ;Marrero, HJ ; Vazquez, DP ; BIOLOGICAL INVASIONS ,2017 ,19 ,615 -623 .

The type of reproductive system may be an important trait for the establishment and maintenance of populations of invasive plant species in new areas, as it can influence their demography and genetics. We studied the breeding system of two exotic invasive species, Rosa rubiginosa and R. canina, in a natural reserve in Argentina, using a combination of pollination experiments. We asked how the different reproductive modes of these species affect the quantity and quality of the fruits and seed produced. Our results show that both invasive rose species have an array of reproductive strategies, and that they are able to invade without pollinators, as they can produce seeds in the same quantity and quality through wind-pollination, self-pollination, and apomixis. Such lack of dependence on pollinators and pollination for reproduction should enhance colonization into new areas, suggesting the need of intensive monitoring of spread and dispersal. Considering that both species are successful invaders in the region, our results are in line with Baker's rule, which posits that plants capable of uniparental reproduction are more likely to invade new areas.

Ecology and nesting biology of the wood-boring bee Trichothurgus laticeps (Hymenoptera: Megachilidae) in a Monte desert reserve in mid-western Argentina

Vitale, N ;Vazquez, DP ; APIDOLOGIE ,2017 ,48 ,31 -40 .

Studying bee nests can enlighten our understanding of feeding specialization and phylogenetic relationships of bees. We studied the nesting and feeding habits of Trichothurgus laticeps in the Monte desert ecosystem. Our results show that T. laticeps is attracted to pre-existing cavities in wood (trap nests), which were further excavated for nest construction; nest cells are unlined and provisioned almost exclusively with pollen of the cactus Opuntia sulphurea. The species overwinters inside a hard cocoon. Our results reinforce the hypothesis previously proposed by other authors that the unworked pollen mass and oligolecty are plesiomorphic characters in the Megachilidae, and that the wood-boring behavior for nest construction indicates convergent evolution with the Xylocopinae. We also propose that the cocoon structure might represent an evolutionary novelty for the Lithurginae.

Ecological and evolutionary impacts of changing climatic variability

Vazquez, DP ;Gianoli, E ; Morris, WF ; Bozinovic, F ; BIOLOGICAL REVIEWS ,2017 ,92 ,22 -42 .

While average temperature is likely to increase in most locations on Earth, many places will simultaneously experience higher variability in temperature, precipitation, and other climate variables. Although ecologists and evolutionary biologists widely recognize the potential impacts of changes in average climatic conditions, relatively little attention has been paid to the potential impacts of changes in climatic variability and extremes. We review the evidence on the impacts of increased climatic variability and extremes on physiological, ecological and evolutionary processes at multiple levels of biological organization, from individuals to populations and communities. Our review indicates that climatic variability can have profound influences on biological processes at multiple scales of organization. Responses to increased climatic variability and extremes are likely to be complex and cannot always be generalized, although our conceptual and methodological toolboxes allow us to make informed predictions about the likely consequences of such climatic changes. We conclude that climatic variability represents an important component of climate that deserves further attention.

Spatial patterns of soil resources under different land use in Prosopis woodlands of the Monte desert

Meglioli, PA ;Aranibar, JN ; Villagra, PE ; Riveros, CV ; CATENA ,2017 ,149 ,86 -97 .

Changes in the spatial distribution of resources constitute an indicator of degradation of arid grazing lands. In arid and semi-arid ecosystems, the distribution of soil resources has been commonly associated with the structure and the spatial arrangements of the vegetation. Although the formation of "fertile islands" beneath vegetation patches is well documented, much less is known about the changes induced by grazing systems on the distribution of soil resources. We examine how pastoralist settlements are affecting the spatial distribution of soil resources and the soil nutrient balance in central-western woodlands of Argentina. We analyzed the distribution of soil water, chloride, nitrate, total nitrogen, and organic matter at increasing distances from livestock corrals and in undisturbed woodlands, at different soil depths. We also calculated variation indexes of soil organic matter and total nitrogen produced by livestock settlements, as an indicator of degree of deterioration or improvement of the soils. The transects located in pastoralist settlements demonstrated an increasing centripetal gradient in availability of soil water and nutrients compared to transects outside of these disturbed areas. Livestock corrals create local hotspots of nutrient enrichment, but when we analyzed the effects of livestock settlements at a higher spatial scale, we found net losses of soil organic matter and total nitrogen. We conclude that the coupling between nutrient and patch dynamics is disrupted by the pastoralist settlements, which caused a redistribution of soil resources, controlled by the location from the livestock corrals. The processes that promote nutrient losses, such as ammonium volatilization, denitrification, nitrate leaching, organic matter oxidation, manure exports, and soil erosion, are relatively higher than the extra inputs of dung and urine. Therefore, this study emphasizes the role of grazing systems as modulators of water and nutrient fluxes, and soil nutrient balance. (C) 2016 Elsevier B.V. All rights reserved.

An unaware agenda: interictal consciousness impairments in epileptic patients

Moguilner, S ;Garcia, AM ; Mikulan, E ; Garcia, MD ; Vaucheret, E ; Amarillo, Y ; Bekinschtein, TA ; Ibanez, A ; NEUROSCIENCE OF CONSCIOUSNESS ,2017 ,3 ,-.

Consciousness impairments have been described as a cornerstone of epilepsy. Generalized seizures are usually characterized by a complete loss of consciousness, whereas focal seizures have more variable degrees of responsiveness. In addition to these impairments that occur during ictal episodes, alterations of consciousness have also been repeatedly observed between seizures (i.e. during interictal periods). In this opinion article, we review evidence supporting the novel hypothesis that epilepsy produces consciousness impairments which remain present interictally. Then, we discuss therapies aimed to reduce seizure frequency, which may modulate consciousness between epileptic seizures. We conclude with a consideration of relevant path-ophysiological mechanisms. In particular, the thalamocortical network seems to be involved in both seizure generation and interictal consciousness impairments, which could inaugurate a promising translational agenda for epilepsy studies.

A Novel Mechanism Underlying the Innate Immune Response Induction upon Viral-Dependent Replication of Host Cell mRNA: A Mistake of plus sRNA Viruses' Replicases

Delgui, LR ;Colombo, MI ; FRONTIERS IN CELLULAR AND INFECTION MICROBIOLOGY ,2017 ,7 ,-.

Viruses are lifeless particles designed for setting virus-host interactome assuring a new generation of virions for dissemination. This interactome generates a pressure on host organisms evolving mechanisms to neutralize viral infection, which places the pressure back onto virus, a process known as virus-host cell co-evolution. Positive-single stranded RNA (+sRNA) viruses are an important group of viral agents illustrating this interesting phenomenon. During replication, their genomic +sRNA is employed as template for translation of viral proteins; among them the RNA-dependent RNA polymerase (RdRp) is responsible of viral genome replication originating double-strand RNA molecules (dsRNA) as intermediates, which accumulate representing a potent threat for cellular dsRNA receptors to initiate an antiviral response. A common feature shared by these viruses is their ability to rearrange cellular membranes to serve as platforms for genome replication and assembly of new virions, supporting replication efficiency increase by concentrating critical factors and protecting the viral genome from host anti-viral systems. This review summarizes current knowledge regarding cellular dsRNA receptors and describes prototype viruses developing replication niches inside rearranged membranes. However, for several viral agents it's been observed both, a complex rearrangement of cellular membranes and a strong innate immune antiviral response induction. So, we have included recent data explaining the mechanism by, even though viruses have evolved elegant hideouts, host cells are still able to develop dsRNA receptors-dependent antiviral response.

Development Of garlic bioactive compounds analytical methodology based on liquid phase microextraction using response surface design. Implications for dual analysis: Cooked and biological fluids samples

Ramirez, DA ;Locatelli, DA ; Torres-Palazzolo, CA ; Altamirano, JC ; Camargo, AB ; FOOD CHEMISTRY ,2017 ,215 ,493 -500 .

Organosulphur compounds (OSCs) present in garlic (Allium sativum L.) are responsible of several biological properties. Functional foods researches indicate the importance of quantifying these compounds in food matrices and biological fluids. For this purpose, this paper introduces a novel methodology based on dispersive liquid-liquid microextraction (DLLME) coupled to high performance liquid chromatography with ultraviolet detector (HPLC-UV) for the extraction and determination of organosulphur compounds in different matrices. The target analytes were allicin, (E)- and (Z)-ajoene, 2-vinyl-4H-1,2-dithiin (2-VD), diallyl sulphide (DAS) and diallyl disulphide (DADS). The microextraction technique was optimized using an experimental design, and the analytical performance was evaluated under optimum conditions. The desirability function presented an optimal value for 600 mu L of chloroform as extraction solvent using acetonitrile as dispersant. The method proved to be reliable, precise and accurate. It was successfully applied to determine OSCs in cooked garlic samples as well as blood plasma and digestive fluids. (C) 2016 Elsevier Ltd. All rights reserved.

Freely Available Tool (FAT) for automated quantification of lipid droplets in stained cells

Masone, D ;Gojanovich, AD ; Frontini-Lopez, YR ; Del Veliz, S ; Uhart, M ; Bustos, DM ; BIOCELL ,2017 ,41 ,55 -58 .

In this study, we propose an automatic procedure for digital image processing. We describe a method that can efficiently quantify and characterize lipid droplets distributions in different cell types in culture. Prospectively, the lipid droplets detection method described in this work could be applied to static or time-lapse data, collected with a simple visible light or fluorescence microscopy equipment. Fully automated algorithms were implemented in Octave, a freely available scientific package.

Evidence for maternal transmission of a putative endosymbiont in the digestive gland of Pomacea canaliculata (Architaenioglossa, Ampullariidae)

Koch, E ;Vega, IA ; Castro-Vazquez, A ; BIOCELL ,2017 ,41 ,59 -61 .

The digestive gland of the apple snail Pomacea canaliculata lodges two types of pigmented corpuscles (identified as C and K corpuscles) which has been proposed as endosymbiont/s. Both corpuscular types are always present in the digestive gland of adult snails, they are released into the tubuloacinar lumen and are later expelled in the feces. On their part, hatchlings lack any C or K corpuscles in the digestive gland as well as in their feces, whereas C corpuscles appear in both the gland and feces within one week after hatching. Hence, it is possible that the detritivorous hatchlings acquire the putative C-endosymbiont from feces in the sediments where they live, i.e. through 'lateral' or 'horizontal' transmission. This possibility was put to test in an experiment in which we prevented any lateral transmission, by a 7-days aseptic culture, with no food, of aseptically obtained hatchlings. At the end of the experiment, we observed that most juveniles had survived the culture period, and hence the digestive glands and feces of survivors were studied by light microscopy of resin embedded, toluidine blue-stained sections. All studied glands and fecal samples showed C corpuscles. It is concluded that lateral transmission of the endosymbiont, if any, is not indispensable for the acquisition of the endosymbiont by hatchlings.

INTER-NODAL SPACES IN NORTHERN PATAGONIA: BIOGEOGRAPHY, INFORMATION, AND SOCIAL MECHANISMS OF INTERACTION

Barberena, R ;Villanueva, GR ; Lucero, G ; Fernandez, MV ; Rughini, AA ; Sosa, P ; ESTUDIOS ATACAMENOS ,2017 ,,57 -75 .

The analysis of internodal spaces in archaeological scale offers a frame useful for integrating questions produced from different theoretical stands, which are actually complementary. The goal of this paper is to assess the role of internodal spaces for inter-group interaction in northern Patagonia from a biogeographical perspective. First, we present the theoretical-methodological frame that guides this proposal. There is important geographical and ecological variation in those parts of a given landscape that can be considered as internodes during the past, which should be characterized as a first step to assess their socio-demographic dynamics. We suggest that there are two key ecological variables that make up the basis of internodes: a) gradient of ecological variation in resources; b) spatial scale of the internodes. Secondly, based on ethnographic information, we describe in a simple manner the possible social mechanisms of interaction that structure and regulate the access to and circulation across internodes. By using this frame, we intend to model the archaeological dynamics of the human use of internodal areas in northern Patagonia. In third place, we explore the role of two lines of research that may constitute proxies on social interaction and circulation of information/objects in space: rock art and obsidian geochemistry. Finally, we consider the preliminary contribution of this research, suggesting paths for future development of these ideas.

Cathodes of spent Li-ion batteries: Dissolution with phosphoric acid and recovery of lithium and cobalt from leach liquors

Pinna, EG ;Ruiz, MC ; Ojeda, MW ; Rodriguez, MH ; HYDROMETALLURGY ,2017 ,167 ,66 -71 .

This paper presents the study of an innovative process: the reductive dissolution of mixed lithium cobalt oxide contained in the cathodes of spent Li-ion batteries with phosphoric acid. The studied parameters were: reaction time, temperature, stirring speed, solid-liquid ratio and concentrations of the leaching agent (H3PO4) and the reducing agent (H2O2). Reactants and products were characterized by atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results showed that the reducing dissolution process with phosphoric acid is an efficient way for the extraction of lithium and cobalt, achieving dissolution values close to 100%. In addition, a recovery of 88% of Li + as Li3PO4 and 99% of Co+2 as CoC2O4, with purities of 98.3% and 97.8% was found respectively. (C) 2016 Elsevier B.V. All rights reserved.

Identification of selected CITES-protected Araucariaceae using DART TOFMS

Evans, PD ;Mundo, IA ; Wiemann, MC ; Chavarria, GD ; McClure, PJ ; Voin, D ; Espinoza, EO ; IAWA JOURNAL ,2017 ,38 ,266 -+ .

Determining the species source of logs and planks suspected of being Araucaria araucana (Molina) K. Koch (CITES Appendix I) using traditional wood anatomy has been difficult, because its anatomical features are not diagnostic. Additionally, anatomical studies of Araucaria angustifolia (Bertol.) Kuntze, Araucaria heterophylla (Salisb.) Franco, Agathis australis (D. Don) Lindl., and Wollemia nobilis W. G. Jones, K. D. Hill & J. M. Allen have reported that these taxa have similar and indistinguishable anatomical characters from A. araucana. Trans-national shipments of illegal timber obscure their geographic provenance, and therefore identification using wood anatomy alone is insufficient in a criminal proceeding. In this study we examine the macroscopic appearance of selected members of the Araucariaceae and investigate whether analysis of heartwood chemotypes using Direct Analysis in Real Time (DART) Time-of-Flight Mass Spectrometry (TOFMS) is useful for making species determinations. DART TOFMS data were collected from 5 species (n = 75 spectra). The spectra were analyzsed statistically using supervised and unsupervised classification algorithms. Results indicate that A. araucana can be distinguished from the look-alike taxa. Another statistical inference of the data suggests that Wollemia nobilis is more similar and within the same clade as Agathis australis. We conclude that DART TOFMS spectra can help in making species determination of the Araucariaceae even when the geographic provenance is unknown.

Nesting ecology of sympatric species of wool carder bees (Hymenoptera: Megachilidae: Anthidium) in South America

Vitale, N ;Gonzalez, VH ; Vazquez, DP ; JOURNAL OF APICULTURAL RESEARCH ,2017 ,56 ,497 -509 .

Using a total of 14,043 trap-nests (potential nest for bees), we documented the nest architecture, host plants, seasonality, and associated organisms of the following six native species of Anthidium (Megachilidae: Anthidiini) from the Central Monte Desert in Mendoza, Argentina: A. andinum Jo "rgensen; A. chubuti Cockerell; A. decaspilum Moure; A. friesei Cockerell; A. rubripes Friese; and A. vigintipunctatum Friese. Each species exhibited unique features in the arrangement of the fibers used to make their cells, and in the type of material used in the nest plug. Bees used a total of 41 plant species, but relied heavily on Prosopis flexuosa (Fabaceae) and Larrea spp. (Zygophyllaceae). Most bee species are univoltine and exhibited delayed emergence. The oil beetle Nemognatha sp. (Coleoptera: Meloidae) and the cuckoo wasp Chrysis striatula Bohart (Hymenoptera: Chrysididae) are recorded for the first time for Anthidium. Nemognatha sp. was the most common brood parasite but C. striatula caused the highest brood mortality.

Molecular-level insight into the binding of arginine to a zwitterionic Langmuir monolayer

Klug, J ;Masone, D ; Del Popolo, MG ; RSC ADVANCES ,2017 ,7 ,30862 -30869 .

Solutions of the cationic amino-acid arginine (Arg(+)) in contact with a phospholipid monolayer are investigated by molecular dynamics simulations. The results show that Arg(+) binds strongly to the lipid/water interface, with adsorption free-energies ranging from -43.8 to -22.2 kJ mol(-1), depending on the amino-acids concentration. The large binding energies are attributed to hydrogen bonding between the charged moieties Arg(+) and the phosphate and carbonyl groups of the phospholipids, that compensate for changes in the levels of hydration upon adsorption. We show that a concentrated layer of Arg(+), tightly bound to the interface, has little effect on the compression isotherm and the lateral mechanical properties of the monolayer, while having a substantial impact on the interfacial electrostatic potential and the lateral mobility of the lipids. These effects are readily explained in terms of the arrangement that the amino-acids adopt when bound to the monolayer.

Synthesis of magnetic polymeric ionic liquid nanocomposites by the Radziszewski reaction

Castro-Grijalba, A ;Reyes-Gallardo, EM ; Wuilloud, RG ; Lucena, R ; Cardenas, S ; RSC ADVANCES ,2017 ,7 ,42979 -42985 .

In the present article a new approach for the synthesis of magnetic polymeric ionic liquid nanocomposites based on the Radziszewski reaction is presented. The Radziszewski reaction is a simple and successful procedure to obtain imidazolium-containing polymers under mild conditions and consists of the reaction between diamine compounds, glyoxal and formaldehyde in an acidic media. If magnetic nanoparticles coated with amino groups are introduced, they can participate as polyamines in the synthesis thus providing a final nanocomposite where polymeric ionic liquids and nanoparticles are combined. The resulting nanocomposite has been characterized using several instrumental techniques aimed at elucidating its chemical composition (infrared spectroscopy and elemental analysis), properties (zeta potential) and morphology (microscopy, X-ray diffraction and dynamic light scattering). Finally, its sorptive ability towards three non-steroidal anti-inflammatory drugs (NSAIDs) such as salicylic acid, ketoprofen and naproxen was evaluated considering the main variables involved in the process. According to the results, the polymeric ionic liquid nanocomposite is a promising sorptive material for analytical purposes.

Analysis of the Existence of Patient Care Team Using Social Network Methods in Physician Communities from Healthcare Insurance Companies

Ito, M ;Appel, AP ; de Santana, VF ; Moyano, LG ; MEDINFO 2017: PRECISION HEALTHCARE THROUGH INFORMATICS ,2017 ,245 ,412 -416 .

Care teams are formed by physicians of different specialties who take care of the same patient. Hence, if we find physicians that share patients with each other probably they configure an informal care team. Thus, the objective of this work is to explore the possibility of finding care teams using Social Network Analysis techniques in physician-physician networks where the physicians have patients in common. For this, we used healthcare insurance claims to build the network. There was the agreement on the metrics of degree and eigenvalue and of betweenness and closeness, also physicians with the 5 highest eigenvalues are highly interconnected. We discuss that the analysis of the physician-physician network with metrics of centrality is promising to reveal informal care teams. The high potential in calculating these metrics is verified from the results to evaluate member's performance and with that how to take actions to improve the work of the team.

Quality evaluation and discrimination of flavouring process of garlic-flavoured vegetable oils

Gonzalez, R ;Vidoni, M ; Locatelli, D ; Camargo, A ; INTERNATIONAL JOURNAL OF FOOD PROPERTIES ,2017 ,20 ,S1016 -S1024 .

In this study, the effects of two garlic-flavouring processes on quality parameters and the organosulphur compound profile were investigated. The results showed that the addition of fresh garlic increased acidity and peroxide values in all flavoured vegetable oils. Mono-, di-, and trisulphides were mainly present in aromatised oils, while allicin, ajoene, and vinyl-dithiins were found in macerated oils. Analyses of the principal components demonstrate that flavoured oils could be discriminated according to the flavouring processes. The experiments carried out in this study would allow one to predict the results of a flavouring procedure on an unknown sample and, consequently, its potential beneficial effects.

Pathogenic fungus in feral populations of the invasive North American bullfrog in Argentina

Ghirardi, R ;Lopez, JA ; Sanabria, EA ; Quiroga, LB ; Levy, MG ; BELGIAN JOURNAL OF ZOOLOGY ,2017 ,147 ,81 -86 .

EVALUATION OF CYTOTOXIC AND ANTITUMORAL PROPERTIES OF TESSARIA ABSINTHIOIDES (HOOK & ARN) DC, "PAJARO BOBO", AQUEOUS EXTRACT

Persia, FA ;Rinaldini, E ; Carrion, A ; Hapon, MB ; Gamarra-Luques, C ; MEDICINA-BUENOS AIRES ,2017 ,77 ,283 -290 .

Higher plants have provided various natural derived drugs used currently in western medicine. Tessaria absinthioides (Hook. & Arn.) DC, Asteraceae, is a native plant from South-America with reported ethnopharmacological and culinary uses. Despite recent scientific reports about plants properties, there is not a well conducted research about its anticancer and potential toxic effects. The current work demonstrates the plant aqueous extract composition; the in vitro induced cytotoxicity, and explores, in vivo, its oral toxicity and antitumoral effects. Composition of aqueous extract was determined by phytochemical reactions. Cytotoxicity was tested in tumoral (Hela, Gli-37, HCT-116 and MCF-7) and non-tumoral (HBL-100) cells, using MTT assay. Oral toxicity and the antitumor activity against colorectal carcinoma were studied in rodents. The chemical analysis revealed the presence of flavonoids, carbohydrates, sterols, terpenes and tannins. Cytotoxicity towards tumoral cells was observed (CV50: 3.0 to 14.8 mu g/ml); while in non-tumoral cells, extracts evidenced a selective reduced toxicity (CV50: 29.5 mu g/ ml). Oral administration of the extract does not induce acute nor dose-repeated toxicity at doses up to 2000 mg/kg and 1000 mg/kg/day, respectively. The antitumoral effect was confirmed by a significant increase in a median survival from 24 weeks (non-treated) to 30 weeks (T. absinthioides treated). The present data indicate that T. absinthioides extract exhibits cytotoxicity against cancer cell lines, with no-toxic effects and significant antitumoral effects in colorectal cancer when is orally administrated. In conclusion, T. absinthioides possesses selective cytotoxicity and antitumoral activities, making its plant derivatives products promising for cancer research and treatment.

Simulation of Tantalum Nanocrystals Under Shock-Wave Loading: Dislocations and Twinning

Tramontina, DR ;Hahn, EN ; Meyers, MA ; Bringa, EM ; SHOCK COMPRESSION OF CONDENSED MATTER - 2015 ,2017 ,1793 ,-.

We simulate strong shock waves in nanocrystalline tantalum using atomistic molecular dynamics simulations, for particle velocities in the range 0.35-2.0 km s(-1), which induce pressures in the range 20-195 GPa. Our simulations explore strain rates in the range 108 s(-1) - 1010 s(-1), and lead to a peak strength in the range 3-15 GPa. Nanocrystalline tantalum exposed to strong shock waves demonstrates deformation enabled by concomitant dislocations, twinning, and grain boundary activity at a variety of particle velocities. Twinning is observed for a mean grain size of 7 nm, starting at around 32 GPa, in disagreement with models which predict a Hall-Petch behavior for twinning, i.e. a twinning stress scaling with grain size d as d(-0.5), and supporting the presence of an inverse Hall-Petch effect for twinning at small grain sizes.

Feeding strategies of a small mammal (Phyllotis xanthopygus, Rodentia Cricetidae) at diverse altitudes in the Central Andes, Argentina

Sassi, PL ;Cuevas, MF ; Menendez, J ; Dacar, MA ; ETHOLOGY ECOLOGY & EVOLUTION ,2017 ,29 ,351 -366 .

Knowledge of feeding habits not only contributes information related to the resources that individuals need to survive and breed, but also leads to insights about the interactions between a species and its environment. The optimal foraging theory explains diet selection by several attributes of the trophic scenario such as availability, diversity, quality and predictability of food. Other models propose that digestive tract mass increases under high metabolic demands by cold, affecting food choice and intake. Thus, diet selection emerges as a behavioural trait shaped by intrinsic and extrinsic factors. The goal of our study was to determine variation in the trophic scenario among sites at different elevations, as well as variation in phenotypic traits relevant to the nutritional and energy balance in Phyllotis xanthopygus. This small rodent is widely distributed along the Andes Mountains. We assessed diet selection and digestive tract size in individuals collected at three elevations across its distribution range. Results on dietary proportion of specific trophic categories (green parts, fruits and arthropods) showed that P. xanthopygus alternates between omnivory and granivory/frugivory. Richness, diversity and quality of the available resources evidenced a relatively low-quality trophic scenario at high altitude. Nevertheless, the diets built in by animals from diverse altitudes lacked differentiation in quality or diversity. P. xanthopygus seems to behaviourally compensate environmental variation to cope with nutritional requirements, by changing diet composition and proportion of items included. The resultant uniform diet quality is consistent with the absence of variation in the gastrointestinal tract size. Considering the spatial variability and seasonality of the region, a behavioural response is probably the most convenient strategy to overcome short-term environmental heterogeneity. In a plastic species such as P. xanthopygus, behaviour is a fundamental aspect to take into account by predictive models in the forecasts of climate change effects on biological diversity.

Description of Silvinichthys pedernalensis n. sp (Teleostei, Siluriformes) from the Andean Cordillera of southern South America

Fernandez, L ;Sanabria, EA ; Quiroga, LB ; ANIMAL BIODIVERSITY AND CONSERVATION ,2017 ,40 ,41 -47 .

Description of Silvinichthys pedernalensis n. sp. (Teleostei, Siluriformes) from the Andean Cordillera of southern South America.-Silvinichthys pedernalensis, a new species, is described from an Andean stream in Provincia San Juan, Argentina, based on its coloration pattern, and its meristic, morphometric and osteological characters. S. pedernalensis differs markedly from all other known members of the genus Silvinichthys as a result of the combination of the absence of pelvic girdle and fin, the wide supraorbital bone, the number of interopercle odontodes 14-18, the number of opercular odontodes 6-8, the branched pectoral-fin rays 7, the dorsal-fin rays 11, the number of dorsal pterygiophore 7, the branchiostegal rays 6, the dorsal procurrent caudal-fin rays 14 and ventral 15, the ribs 16, the vertebrae 39, the dark marmorated pigmentation on the body and head, the head depth 9.9-12.2% SL, the interorbital wide 28.3-36.1% HL, the nasal barbel length 27.3-39.0% SL, the maxillary barbel length 39.5-61.7% SL, the submaxillary barbel length 24.7-41.9% SL, the snout length 40.6-44.4% HL, the body depth 10.1-12.6% SL, the anal base fin 10.2-11.7% SL, and the caudal peduncle length 19.3-21.5% SL.

High resolution satellite derived erodibility factors for WRF/Chem windblown dust simulations in Argentina

Cremades, PG ;Fernandez, RP ; Allende, DG ; Mulena, GC ; Puliafito, SE ; ATMOSFERA ,2017 ,30 ,11 -25 .

A proper representation of dust sources is critical to accurately predict atmospheric particle concentration in regional windblown dust simulations. The Weather Research and Forecasting model with Chemistry (WRF/Cheni) includes a topographic-based erodibility map originally conceived for global scale modeling, which fails to identify the geographical location of dust sources in many regions of Argentina. Therefore, this study aims at developing a method to obtain a high-resolution erodibility map suitable for regional or local scale modeling using WRF/Chem. We present two independent approaches based on global methods to estimate soil erodibility using satellite retrievals, i.e. topography from the Shuttle Radar Topography Mission (SRTM) and surface reflectance from the Moderate Resolution Imaging Spectroradiometer (MODIS). Simulation results of a severe Zonda wind episode in the arid central-west Argentina serve as bases for the analysis of these methods. Simulated dust concentration at surface level is compared with particulate matter measurements at one site in Mendoza city. In addition, we use satellite aerosol optical depth (AOD) retrievals to investigate model performance in reproducing spatial distribution of dust emissions. The erodibility map based on surface reflectance from MODIS improves the representation of small scale features, and increases the overall dust aerosol loading with respect to the standard map included by default. Simulated concentrations are in good agreement with measurements as well as satellite derived dust spatial distribution.

Dissimilar evolutionary histories of two resistance gene families in the genus Solanum

Segura, DM ;Masuelli, RW ; Sanchez-Puerta, MV ; GENOME ,2017 ,60 ,17 -25 .

Genomic analyses have shown that most genes in eukaryotic lineages belong to families. Gene families vary in terms of number of members, nucleotide similarity, gene integrity, expression, and function. Often, the members of gene families are arranged in clusters, which contribute to maintaining similarity among gene copies and also to generate duplicates through replication errors. Gene families offer us an opportunity to examine the forces involved in the evolution of the genomes and to study recombination events and genomic rearrangements. In this work, we focused on the evolution of two plant resistance gene families, Sw5 and Mi-1, and analyzed the completely sequenced nuclear genomes of potato and tomato. We first noticed that the potato genome carries larger resistance gene families than tomato, but all gene copies are pseudogenes. Second, phylogenetic analyses indicated that Sw5 and Mi-1 gene families had dissimilar evolutionary histories. In contrast to Sw5, Mi-1 homologues suffered repeated gene conversion events among the gene copies, particularly in the tomato genome.

Automatic Myocardial Segmentation by Using A Deep Learning Network in Cardiac MRI

Curiale, AH ;Colavecchia, FD ; Kaluza, P ; Isoardi, RA ; Mato, G ; 2017 XLIII LATIN AMERICAN COMPUTER CONFERENCE (CLEI) ,2017 ,,-.

Cardiac function is of paramount importance for both prognosis and treatment of different pathologies such as mitral regurgitation, ischemia, dyssynchrony and myocarditis. Cardiac behavior is determined by structural and functional features. In both cases, the analysis of medical imaging studies requires to detect and segment the myocardium. Nowadays, magnetic resonance imaging (MRI) is one of the most relevant and accurate non-invasive diagnostic tools for cardiac structure and function.

Potential protective role of nitric oxide and Hsp70 linked to functional foods in the atherosclerosis

Camargo, AB ;Manucha, W ; CLINICA E INVESTIGACION EN ARTERIOSCLEROSIS ,2017 ,29 ,36 -45 .

Atherosclerosis, one of the main pathologic entities considered epidemic and a worldwide public health problem, is currently under constant review as regards its basic determining mechanisms and therapeutic possibilities. In this regard, all patients afflicted with the disease exhibit mitochondrial dysfunction, oxidative stress and inflammation. Interestingly, nitric oxide a known vasoactive messenger gas has been closely related to the inflammatory, oxidative and mitochondrial dysfunctional process that characterizes atherosclerosis. In addition, it has recently been demonstrated that alterations in the bioavailability of nitric oxide would induce the expression of heat shock proteins. This agrees with the use of functional foods as a strategy to prevent both vascular aging and the development of atherosclerosis. Finally, a greater knowledge regarding the mechanisms implied in the development of atherosclerosis will enable proposing new and possible hygiene, health and therapeutic interventions. (C) 2016 Sociedad Espanola de Arteriosclerosis. Published by Elsevier Espana, S.L.U. All rights reserved.

A new large panchelid turtle (Pleurodira) from the Loncoche Formation (upper Campanian-lower Maastrichtian) of the Mendoza Province (Argentina): Morphological, osteohistological studies, and a preliminary phylogenetic analysis

de la Fuente, MS ;Maniel, I ; Jannello, JM ; Sterli, J ; Riga, BG ; Novas, F ; CRETACEOUS RESEARCH ,2017 ,69 ,147 -168 .

A new genus and species of panchelid turtle (Mendozachelys wichmanni gen. et sp. nov.) from the upper Campanian-lower Maastrichtian Loncoche Formation (southern Mendoza Province, Argentina) is described here. This species is represented by only one complete and articulated large specimen (carapace length estimated in 950 mm) that was recovered from tidal flat deposits. A detailed morphological and osteohistological description is made, recognizing autapomorphic characters that allow differentiating this taxon from the rest of extant and extinct panchelids. Osteohistological characters suggest an aquatic to semi-aquatic life style for Mendozachelys wichmanni gen. et sp. nov. Phylogenetic analysis based on morphological data suggested that this new taxon is nested within crown Chelidae. Both phylogenetic signals (morphological and molecular) about the assessment of long-necked chelids monophyly or polyphyly are discussed. (C) 2016 Elsevier Ltd. All rights reserved.