Vibrational assignments of two polymorphic forms of metaxolone by using DFT calculations and the SQM methodology Iramain, Maximiliano Alberto; Márquez, María J.; Ledesma, Ana Estela; Brandan, Silvia Antonia A theoretical study has been performed on the musclerelaxant 5-[(3, 5-dimethylphenoxy)methyl]-1,3-oxazolidin-2-one, of generic name metaxolone (MTX), by using the hybridB3LYP/6-31G calculations in the gas phase and theexperimental available infrared and Raman spectra in thesolid phase. Three C1, C2 and C3 isomers were found in thepotential energy surface (PES) but only two of them, C1 andC2 correspond to those experimentally reported polymorphicforms A and B, respectively. The absence of C3 isomer couldbe easily explained by the quite high values in the dihedralC5-C7-O2-C9 and O1-C5-C7-O2 angles different from thoseexperimental structures reported for the two polymorphicforms A and B of MTX. On the other hand, the higher bondorders values together with the high topological propertiesobserved for the oxazolidinone ring of C1 could possiblysupport their existence despite this isomer has highest energythan C2 and C3. The natural bond orbital (NBO) analysesreveal the high stabilities of C1 and C2 while the atoms inmolecules(AIM) study suggests that the ringdimethylphenoxy-methyl practically do not have influence onthe properties of MTX. The frontier orbitals show that theisomers of MTX have reactivities and electrophilicity indexessimilar to antiviral thymidine while their nucleophilicityindexes present values closer to antimicrobial thione. Inaddition, the complete vibrational assignments of those twostable isomers were performed by using the experimentalavailable FT-IR and FT-Raman spectra, their normal internalcoordinates,the scaled quantum mechanical force field(SQMFF) methodology and the Molvib program.Theharmonic force fields for the two isomers and theircorresponding force constants were also reported. The forceconstants values are in agreement with values reported in theliterature for species with similar groups.

Protein Fluctuations and Cavity Changes Relationship Barletta Roldan, Patricio German; Fernández Alberti, Sebastián Protein cavities and tunnels are critical for function. Ligand recognition and binding, transport, and enzyme catalysis require cavities rearrangements. Therefore, the flexibility of cavities should be guaranteed by protein vibrational dynamics. Molecular dynamics simulations provide a framework to explore conformational plasticity of protein cavities. Herein, we present a novel procedure to characterize the dynamics of protein cavities in terms of their volume gradient vector. For this purpose, we make use of algorithms for calculation of the cavity volume that result robust for numerical differentiations. Volume gradient vector is expressed in terms of principal component analysis obtained from equilibrated molecular dynamics simulations. We analyze contributions of principal component modes to the volume gradient vector according to their frequency and degree of delocalization. In all our test cases, we find that low frequency modes play a critical role together with minor contributions of high frequency modes. These modes involve concerted motions of significant fractions of the total residues lining the cavities. We make use of variations of the potential energy of a protein in the direction of the volume gradient vector as a measure of flexibility of the cavity. We show that proteins whose collective low frequency fluctuations contribute the most to changes of cavity volume exhibit more flexible cavities.

Phocoena spinipinnis, Burmeister's Porpoise Félix, F.; Alfaro Shigueto, J.; Reyes, J.; Mangel, J.; Dellabianca, N.; Heinrich, S.; Crespo, Enrique Alberto El texto incluye una revisión taxonómica, el rango de distribución, información poblacional, ecológica, genética, amenazas y estado de conservación.

De fiesta antes de la fiesta: relación entre esta práctica de consumo de alcohol con los problemas derivados del uso de alcohol en jóvenes argentinos; Association between attendance to pregaming events and alcohol-related consequences in argentinean youth Pilatti, Angelina; Etkin, Paula; Urioste Parra, Eugenia; Pautassi, Ricardo Marcos Objetivos: Este trabajo describe el perfil de consumo de alcohol de jóvenes asistentes a previas y analiza la relación entre la frecuencia de asistencia a previas, y el consumo de alcohol en las mismas, con la experimentación de consecuencias negativas, así como la modulación de estas variables por la edad de inicio de consumo. Se examina el poder predictivo de la frecuencia de asistencia a previas sobre la cantidad de problemas por consumo de alcohol controlando el efecto de variables sociodemográficas, volumen de alcohol consumido, frecuencia de consumo episódico elevado y edad de inicio del consumo de alcohol. Método: 493 participantes (62.3% mujeres) completaron una encuesta online para determinar la frecuencia de asistencia a previas y cantidad de consumo de alcohol en previas, consumo riesgoso de alcohol, consumo de alcohol durante una semana típica de consumo y durante la semana de consumo más intensa y consecuencias negativas del consumo de alcohol. Resultados: se encontró una correlación significativa y positiva entre la frecuencia y cantidad de consumo de alcohol en previas con la frecuencia de consumo riesgoso de alcohol y con la cantidad de problemas experimentados. El efecto de la frecuencia de asistencia a previas sobre la cantidad de consecuencias negativas fue significativo controlando el efecto de otras variables independientes. Conclusiones: Los resultados de este trabajo indican que el contexto recreativo de las previas implicaría riesgos distintivos, representando un factor de vulnerabilidad para el desarrollo de un mayor número de problemas con el alcohol.; Aims. This work described patterns of alcohol drinking in youth that attended pregaming events (i.e., the practice of drinking alcoholic beverages before attending a social/sporting event) and analyzed the relationship between frequency of pregaming, alcohol consumption at pregaming and alcohol-related negative consequences; and the modulation of these variables by the age of onset of alcohol drinking. Methods. 493 participants (62.3% women) completed an online survey that determine the frequency of attendance at pregaming events, the quantity of alcohol consumed in those events, risky alcohol drinking, alcohol consumption during a typical drinking week or during the most intense drinking week, and the number of negative alcohol-related consequences. Results. There was a significant and positive correlation between frequency and quantity of alcohol consumed at pregaming with frequency of risky drinking, and with the number of negative alcohol-related consequences. The effect of frequency of attendance at pregaming events upon the number of negative alcoholrelated consequences was significant after controlling for the effect of the other independent variables. Conclusions. The results suggest that this consumption practice (i.e., pregaming) involves distinctive risks and represents a vulnerability factor for the development of negative alcohol-related consequences.

TT-deformations, AdS/CFT and correlation functions Giribet, Gaston Enrique A solvable irrelevant deformation of AdS3/CFT2 correspondence leading to a theory with Hagedorn spectrum at high energy has been recently proposed. It consists of a single trace deformation of the boundary theory, which is inspired by the recent work on solvable TT¯ deformations of two-dimensional CFTs. Thought of as a worldsheet σ-model, the interpretation of the deformed theory from the bulk viewpoint is that of string theory on a background that interpolates between AdS3 in the IR and a linear dilaton vacuum of little string theory in the UV. The insertion of the operator that realizes the deformation in the correlation functions produces a logarithmic divergence, leading to the renormalization of the primary operators, which thus acquire an anomalous dimension. We compute this anomalous dimension explicitly, and this provides us with a direct way of determining the spectrum of the theory. We discuss this and other features of the correlation functions in presence of the deformation.

A QQ → QQ planar double box in canonical form Bianchi, Marco S.; Leoni Olivera, Matías We consider a planar double box with four massive external momenta and two massive internal propagators. We derive the system of differential equations for the relevant master integrals, cast it in canonical form, write it as a dlog form and solve it in terms of iterated integrals up to depth four.

Measurements of Higgs boson properties in the diphoton decay channel with 36 fb−1 of pp collision data at s√=13 TeV with the ATLAS detector Aaboud, M.; Aad, G.; Abbott, B.; Abdinov, O.; Abeloos, B.; Alconada Verzini, María Josefina; Alonso, Francisco; Arduh, Francisco Anuar; Dova, Maria Teresa; Hoya, Joaquín; Monticelli, Fernando Gabriel; Wahlberg, Hernan Pablo; Bossio Sola, Jonathan David; Marceca, Gino; Otero y Garzon, Gustavo Javier; Piegaia, Ricardo Nestor; Sacerdoti, Sabrina; Zibell. A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; Nedden, M. zur; Zurzolo, G.; Zwalinski, L.; The ATLAS Collaboration Properties of the Higgs boson are measured in the two-photon final state using 36.1 fb−1 of proton-proton collision data recorded at s√=13 TeV by the ATLAS experiment at the Large Hadron Collider. Cross-section measurements for the production of a Higgs boson through gluon-gluon fusion, vector-boson fusion, and in association with a vector bosonor a top-quark pair are reported. The signal strength, defined as the ratio of the observed to the expected signal yield, is measured for each of these production processes as well as inclusively. The global signal strength measurement of 0.99±0.14 improves on the precision of the ATLAS measurement at s√=7 and 8 TeV by a factor of two. Measurements of gluon-gluon fusion and vector-boson fusion productions yield signal strengths compatible with the Standard Model prediction. Measurements of simplified template cross sections, designed to quantify the different Higgs boson production processes in specific regions of phase space, are reported. The cross section for the production of the Higgs boson decaying to two isolated photons in a fiducial region closely matching the experimental selection of the photons is measured to be 55±10 fb, which is in good agreement with the Standard Model prediction of 64±2 fb. Furthermore, cross sections in fiducial regions enriched in Higgs boson production in vector-boson fusion or in association with large missing transverse momentum, leptons or top-quark pairs are reported. Differential and double-differential measurements are performed for several variables related to the diphoton kinematics as well as the kinematics and multiplicity of the jets produced in association with a Higgs boson. No significant deviations from a wide array of Standard Model predictions are observed.

Asymmetric synthesis of: Trans -4,5-disubstituted γ-butyrolactones involving a key allylboration step. First access to (-)-nicotlactone B and (-)-galbacin Henrion, S.; Macé, A.; Vallejos, Margarita; Roisnel, T.; Carboni, B.; Villalgordo, J.M.; Carreaux, Francois An efficient asymmetric synthesis of trans-4,5-disubstituted γ-butyrolactones from aldehydes and enantioenriched γ-carbamate alkenylboronates is reported. The cornerstone of this strategy is the implementation of sequential [3,3]-allyl cyanate rearrangement/allylboration/nucleophilic addition/cyclisation reactions. Diverse γ-butyrolactones such as the flavouring compounds, (+)-trans-whiskey lactone and (+)-trans-cognac lactone, as well as an advanced intermediate towards the first synthesis of natural products, (-)-nicotlactone B and (-)-galbacin, have thus been obtained.

Encapsulation of Compounds Biphenyls Into SBA-15: Synthesis of Composites for Application Guntero, Vanina Alejandra; Ferretti, Cristián Alejandro; Mancini, Pedro Maximo Emilio; Kneeteman, Maria Nelida Two novel hybrid mesoporous material BVA-SBA and BEG-SBA were designed and synthesized by a process assisted by microwave. The nanoparticles were studied by UV-vis and fluorescence spectroscopy, elemental analysis, nitrogen adsorption-desorption, RMN and FTIR. The results obtained indicates the successful immobilization of BVA and BEG in the mesoporous composite. These systems present the possibility of activating the release of the organic molecules encapsulated into SBA-15, depending on the liquid medium in which the composite are suspended.

Improving access to voting with optimized matchings Duran, Guillermo Alfredo; Giormenti, Mauro; Guajardo, Mario; Pinto, Pablo M.; Rey, Pablo A.; Stier Moses, Nicolás E. Research on political representation has traditionally focused on the design of electoral systems. Yet there is evidence that voting costs result in lower turnout and undermine voters’ confidence in the electoral system. Election administrators can selectively manipulate participation costs for different individuals and groups, leading to biased electoral outcomes. Quantifying the costs of voting and designing fair, transparent and efficient rules for voter assignment to polling stations are important for theoretical and practical reasons. Using analytical models, we quantify the differential costs of participation faced by voters, which we measure in terms of distance to polling stations and wait times to cast a vote. To estimate the model parameters, we use real-world data on the 2013 midterm elections in Argentina. The assignment produced by our model cut average voting time by more than 27%, underscoring the inefficiencies of the current method of alphabetical assignment. Our strategy generates better estimates of the role of geographical and temporal conditions on electoral outcomes.

Biología de nidificación de la abeja eusocial primitiva Augochlora phoemonoe (Halictidae); Nesting biology of the primitively eusocial bee Augochlora phoemonoe (Halicitdae) Dalmazzo, Maria de Los Milagros Se describe la biología de nidificación de la especie eusocial primitiva Augochlora phoemonoe(Halictidae) a partir de observaciones de nidos hallados en el campo y nidos artificiales mantenidos en laboratorio.La especie nidifica en madera en descomposición, aunque puede aceptar otro sustrato como el yeso. Se encontrarondos tipos de estructuras de nidificación: celdas apoyadas al sustrato sin cavidad circundante en campo yceldas dispuestas en forma de racimo rodeadas por una cavidad y sostenidas por un número variable de pilares enlaboratorio. Ambas estructuras presentaron un orificio de entrada rodeado por un anillo de partículas de maderacompactadas y un túnel no ramificado que conduce a las celdas. La hembra fundadora comienza el nido en formasolitaria. Hace primero el orificio de entrada y un túnel no ramificado, luego construye la o las primeras celdas.Las hembras hijas son las que continúan el proceso de construcción del nido durante la etapa social. Las abejascortan y separan con las mandíbulas pequeñas partículas de madera que son transportadas hacia otras partesdel nido donde las compactan utilizando los últimos tergos metasomales. Mediante estos procesos de remoción,transporte y compactación modifican el sustrato, excavan túneles y cavidades, tapizan superficies, y construyenpilares y celdas. Los hallazgos del presente estudio aportan caracteres para la clasificación de las estructuras denidificación para un futuro análisis filogenético dentro de Augochlorini.; The nesting biology of the primitively eusocial bee Augochlora phoemonoe (Halictidae) is described from nests collected in the field and nests constructed and maintained in the laboratory. This species nests in decaying wood, although it may accept plaster as nesting substrate. Two types of nest structure were found: cells laying on the substrate without a surrounding cavity in field conditions, and cells in a cluster supported by a variable number of pillars within a cavity in laboratory. Both structures had an entry hole surrounded by a compacted ring of sawdust, and an unbranched tunnel leading to the cells. The foundress female begins the nest solitarily. First she makes the entrance hole and the tunnel, and then she builds one or a few cells. The daughter females continue the construction of the nest during the social phase. Bees cut and separate the sawdust using the mandibles. Then, the bees transport the sawdust to other part of the nest and compact them using the latest metasomal terga. By the processes of removal, transport and compaction, the bees modify the substrate, excavate the tunnel and cavities, line the walls and construct pillars and cells. The findings of this study contribute with characters for a classification of nesting structures, and for further analysis of Augochlorini phylogeny.

Larval development of Aelurostrongylus abstrusus in experimentally infected Rumina decollata snails Cardillo, Natalia Marina; Ercole, Mariano Emmanuel; Fariña, Fernando Adrián; Pasqualetti, Mariana Ines; Loiza, Yanina Elizabeth; Pérez, Matías Gastón; Bonboni, Ayelen; Ribicich, Miriam Mabel Aelurostrongylus abstrusus is a lungworm distributed worldwide that affects wild and domestic cats, causing bronchopneumonia of varying intensity. Snails serve as intermediate hosts. The aim of the present study was to assess the larval development of A. abstrusus in R. decollata snails and to investigate its potential as an intermediate host. For this purpose, first-stage larvae (L1) of A. abstrusus were obtained from the faeces of naturally infected cats. Doses of 500 L1/snail were given to 24 R. decollata snails, placed on the soil of the breeder chamber, and maintained under laboratory conditions. Three snails were killed at 8, 10, 12, 16, 22, 26, 45 and 55 days post-infection (dpi), and the muscular foot and visceral body were separately digested by an artificial digestion technique. The morphometric parameters of different larval stages were recorded. The mean number of larvae reaching the infective stage at the end of the study (L3) was 262 larvae/snail. The greatest development to L3 was recorded from days16 to 55 pi, during which the isolation was maximum. A. Abstrusus L3 were isolated from the viscera, but isolation from the snail foot was significantly higher. Our results showed for the first time the ability of A. Abstrusus larvae to develop in R. decollata, thus serving as a potential intermediate host.

Sub-ångström cryo-EM structure of a prion protofibril reveals a polar clasp Gallagher Jones, Marcus; Glynn, Calina; Boyer, David R.; Martynowycz, Michael W.; Hernandez, Evelyn; Miao, Jennifer; Zee, Chih Te; Novikova, Irina V.; Goldschmidt, Lukasz; Mc Farlane, Heather T.; Helguera, Gustavo Fernando; Evans, James E.; Sawaya, Michael R.; Cascio, Duilio; Eisenberg, David S.; Gonen, Tamir; Rodriguez, Jose A. The atomic structure of the infectious, protease-resistant, β-sheet-rich and fibrillar mammalian prion remains unknown. Through the cryo-EM method MicroED, we reveal the sub-ångström-resolution structure of a protofibril formed by a wild-type segment from the β2–α2 loop of the bank vole prion protein. The structure of this protofibril reveals a stabilizing network of hydrogen bonds that link polar zippers within a sheet, producing motifs we have named ‘polar clasps’.

Breeding strategies in Melilotus albus Desr., a salt-tolerant forage legume Zabala, Juan Marcelo; Marinoni, Lorena del Rosario; Giavedoni, Julio Alberto; Schrauf, Gustavo Enrique Melilotus albus Desr. is recognized as one of the species with greatest potential as a forage source for ruminants in saline rangelands. The objectives of the current research were threefold: (1) to estimate heritability and genetic correlation of traits associated with winter forage production and regrowth capacity in M. albus prebreeding material, as measured in spaced plants grown in a nonsaline environment; (2) to evaluate winter forage production of a selected population grown in plots at sites with contrasting soil salinities; and (3) to evaluate the agronomic performance of blended (mixed) populations and monocultures of M. albus grown in plots. Results indicated presence of genetic variability associated with winter production and regrowth capacity in a prebreeding population selected for one trait, viz. late flowering. Results also showed that selection in a nonsaline environment did not modify the relative salinity tolerance of M. albus populations. Finally, varietal mixtures (blends) of two selected populations showed a slight increase in and more seasonally balanced dry matter (DM) yield than monocultures. Mixtures combined favorable characteristics from the two selected populations (i.e., highest winter forage production, as expressed in the SP1 population, and highest regrowth capacity, as expressed in the SP2 population). Furthermore, results indicated that M. albus genotypes naturalized in Argentina could be used as genetic resources for sweet clover breeding for saline environments and that alternative breeding approaches could improve forage productivity in saline environments.

Diffusion of Water and Electrolytes in Mesoporous Silica with a Wide Range of Pore Sizes Martínez Casillas, Diana Cristina; Longinotti, María Paula; Bruno, Mariano Martín; Vaca Chávez Fornasero, Fabián; Acosta, Rodolfo Héctor; Corti, Horacio Roberto The diffusion of alkaline chlorides (LiCl, KCl, and CsCl) and water in mesoporous silica samples with pore sizes covering the range from micropores (2 nm) up to mesopores larger than 30 nm have been measured by resorting to a simple diffusional technique in the case of electrolytes and 1H NMR in the case of water. The morphology of the silica samples varies from a microporous structure, an interconnected network of pores, and typical mesoporous materials with ink-bottle pores, with increasing pore size. The release of electrolytes from the silica as a function of time exhibits two differentiated regimes, at short and long times, which correlates quite well with the size of the pores and that of necks of the pores, respectively. The diffusion of water inside the pores follows the same trend with pore size that the diffusion of electrolytes, indicating a coupling between the ions and water diffusional mobilities. The tortuosity effect on the diffusion of all studied electrolytes and water shows a monotonic slight increase with decreasing diameter for pores larger than 5 nm, while the tortuosity factor increases markedly for smaller pores. In microporous and mesoporous silica with pore sizes below 10 nm, the tortuosity factor of Li+ ion is much larger than those for K+ and Cs+ ions, since its diffusion is hindered by a stronger electrostatic interaction with the ionizable silanol groups on the pore wall; and also larger than that for water diffusion which it is retarded by a weaker hydrogen bond interaction with the silanol groups. The differences in tortuosity factors among alkaline chlorides and water become negligible for pore sizes larger than 10 nm. The spin-lattice relaxation time measurements of 1H-water and Li+ ions confirm this behavior.

The pregnane X receptor (PXR) and the nuclear receptor corepressor 2 (NCoR2) modulate cell growth in head and neck squamous cell carcinoma Rigalli, Juan Pablo; Reichel, Matthias; Reuter, Tasmin; Tocchetti, Guillermo Nicolás; Dyckhoff, Gerhard; Herold Mende, Christel; Theile, Dirk; Weiss, Johanna Head and neck squamous cell carcinoma (HNSCC) is the sixth most frequent cancer worldwide. The pregnane X receptor (PXR) is a nuclear receptor regulating several target genes associated with cancer malignancy. We here demonstrated a significant effect of PXR on HNSCC cell growth, as evidenced in PXR knock-down experiments. PXR transcriptional activity is more importantly regulated by the presence of coactivators and corepressors than by PXR protein expression. To date, there is scarce information on the regulation of PXR in HNSCC and on its role in the pathogenesis of this disease. Coactivator and corepressor expression was screened through qRT-PCR in 8 HNSCC cell lines and correlated to PXR activity, determined by using a reporter gene assay. All cell lines considerably expressed all the cofactors assessed. PXR activity negatively correlated with nuclear receptor corepressor 2 (NCoR2) expression, indicating a major role of this corepressor in PXR modulation and suggesting its potential as a surrogate for PXR activity in HNSCC. To test the association of NCoR2 with the malignant phenotype, a subset of three cell lines was transfected with an over-expression plasmid for this corepressor. Subsequently, cell growth and chemoresistance assays were performed. To elucidate the mechanisms underlying NCoR2 effects on cell growth, caspase 3/7 activity and protein levels of cleaved caspase 3 and PARP were evaluated. In HNO97 cells, NCoR2 over-expression decreased cell growth, chemoresistance and increased cleaved caspase 3 levels, caspase activity and cleaved PARP levels. On the contrary, in HNO124 and HNO210 cells, NCoR2 over-expression increased cell growth, drug resistance and decreased cleaved caspase 3 levels, caspase activity and cleaved PARP levels. In conclusion, we demonstrated a role of PXR and NCoR2 in the modulation of cell growth in HNSCC. This may contribute to a better understanding of the highly variable HNSCC therapeutic response.

La potencia de los feminismos latinoamericanos para una ruptura epistemológica con el universalismo eurocéntrico del feminismo hegemónico. Críticas desde el margen Parra, Valeria Fabiana Frente al feminismo eurocéntrico hegemónico -que con sus pretensiones de universalidad invisibiliza a las mujeres que no pertenecen a un sistema de género blanco, binario y burgués-el feminismo latinoamericano: decolonial, materialista, y diverso, se nutre de epistemologías “otras” para construir un conocimiento situado desde las experiencias de vida de las propias mujeres subalternas: indígenas, campesinas, afrodescendientes, migrantes, lesbianas, pobres, mestizas. Excluidas y silenciadas por las demandas de un feminismo que no comprende al género como parte de un entramado complejo en el que la combinación e interseccionalidad de determinaciones vinculadas a la clase, la elección sexual, la pertenencia geopolítica, étnica y cultural, son fundamentales para el estatuto de lxs sujetxs. Ante este panorama, la tarea actual del feminismo debe ser la de ampliar voces y miradas. A lo largo de este trabajo, presentaré argumentos para mostrar que tal propósito puede lograrse desde una perspectiva feminista latinoamericana y decolonial porque la crítica realizada desde el margen posibilita interpelar la hegemonía y visibilizar la alteridad. Lo cual constituye una verdadera ruptura epistemológica.; Face o feminismo hegemônico eurocêntrico–que com suas pretensões de universalidade invisibiliza as mulheres que não pertencem a um sistema de gênero branco, binário e burguês–o feminismo latino-americano: decolonial, materialista e diversificado, nutre-se por epistemologias "outras" para construir um conhecimento localizado a partir das experiências de vida das próprias mulheres subalternas: indígenas, camponeses, afrodescendentes, migrantes, lésbicas, pobres, mestiças. Excluídas e silenciadas pelas exigências de um feminismo que não compreende o gênero como parte de um quadro complexo em que a combinação e a interseção de determinações ligadas à classe, escolha sexual, pertença geopolítica, étnica e cultural são fundamentais para a estatuto dxs sujeitxs. Dado esse panorama, a atual tarefa do feminismo deve ser expandir vozes e olhadas. Ao longo deste trabalho, apresentarei argumentos para mostrar que tal propósito pode ser alcançado a partir de uma perspetiva feminista latino-americana e decolonial porque a crítica feita a partir da margem permite desafiar a hegemonia e tornar visível a alteridade. O que constitui uma verdadeira ruptura epistemológica.

Fire effects on the soil seed bank and post-fire resilience of a semi-arid shrubland in central Argentina Lipoma, Maria Lucrecia; Funes, Guillermo; Díaz, Sandra Myrna Soil seed bank is an important source of resilience of plant communities who suffered disturbances. We analysed the effect of an intense fire in the soil seed bank of a semi-arid shrubland of Córdoba Argentina. We asked if the fire affected seed abundance, floristic and functional composition of the soil seed bank at two different layers (0–5 cm and 5–10 cm), and if fire could compromise the role of the soil seed bank as a source of resilience for the vegetation. We collected soil samples from a burned site and from a control site that had not burned. Samples were installed in a greenhouse under controlled conditions. During 12 months, we recorded all germinated seedlings. We compare soil seed bank with pre-fire vegetation in terms of floristic and functional composition. The high-intensity fire deeply affected the abundance of seeds in the soil, but it did not affect its floristic or functional composition. Floristic and functional composition of soil seed banks – at burned and unburned sites- differed markedly from that of the pre-fire vegetation, although a previous study at the same site indicated high resilience after fire of this plant community. Our results indicate that resilience of this system is not strongly dependent on direct germination from seeds buried in the soil. Other sources of resilience, like colonization from neighbouring vegetation patches and resprouting from underground organs appear to gain relevance after an intense fire.

Preparation of Lignosulfonate-Based Carbon Foams by Pyrolysis and Their Use in the Microencapsulation of a Phase Change Material Palazzolo, Martín Alejandro; Dourges, Marie Anne; Magueresse, Anthony; Glouannec, Patrick; Maheo, Laurent; Deleuze, Hervé Currently, further research on the valorization of lignin is needed to shift biorefineries from a conceptual basis to profitable practice. Providing global warming is a major concern as well, the use of lignin as the sole precursor to elaborate materials with thermal energy storage (TES) applications is especially welcomed in the search for new sustainable solutions. To this end, the preparation of on-demand macroporous carbon foams from calcium lignosulfonate (CaLS) by pyrolysis is described herein, and their capability to microencapsulate phase change materials (PCMs) dedicated to the passive refrigeration of buildings by TES is further assessed as a proof of concept. The as-produced CaLS-based foams were found to be efficient containers for this purpose, displaying any appreciable leakage of PCMs. Furthermore, the thermal properties of the final materials were satisfactory as well, showing that the support does not affect the PCM performance negatively. Considering the process to produce such materials is not only straightforward but also relies on an inexpensive, widely available carbon precursor, it is expected that it serves as a starting point for pilot studies in TES projects.

Nanosilver toxicity in gills of a neotropical fish: Metal accumulation, oxidative stress, histopathology and other physiological effects Ale, Analía; Bacchetta, Carla; Rossi, Andrea Silvana; Galdopórpora, Juan Manuel; Desimone, Martín Federico; de la Torre, Fernando Roman; Gervasio, Susana Graciela; Cazenave, Jimena The widespread and increasing use of silver nanoparticles (AgNP) as biocide results in an unknown release into the aquatic environment. In order to contribute to the understanding of their potential toxicity, the aim of this study was to analyze branchial multiple biomarkers on the neotropical fish Prochilodus lineatus. We exposed fish to sublethal AgNP concentrations: 0 (control), 2.5 and 25.0 µg L−1. After 5 and 15 days, we analyzed in gills total Ag accumulation, oxidative stress markers (antioxidant enzymes, lipid peroxidation and antioxidant capacity against peroxyl radicals), aspartate and alanine aminotransferases activities (ALT, AST) and histopathologies (morphometric analysis, proportion of the secondary lamellae available for gas exchange, reaction indexes, and organ index -Igills-) that included mucus cell count (MCc). The Ag accumulation after 15 days was five times higher than after 5 days in the case of 25.0 μg AgNP L−1-exposure. Regarding oxidative stress, all enzymes activities were inhibited after 5 days at both AgNP concentrations. ALT activity decreased and a reduction in the antioxidant capacity was evidenced after 2.5 µg AgNP L−1 and 15 days. LPO levels and AST activity increased after the highest time of exposure and AgNP concentration, and the same occurred with Igills. MCc increased after 15 days at both AgNP concentrations. The results confirmed that the presence of low AgNP concentrations, in short and subchronic exposures, generates alterations in stress biomarkers and in the structure of this vital organ that are the gills.