Geodynamic controls on the contamination of Cenozoic arc magmas in the southern Central Andes: Insights from the O and Hf isotopic composition of zircon Jones, Rosemary E.; Kirstein, Linda; Kasemann, Simone A.; Dhuime, Bruno; Elliott, Tim; Litvak, Vanesa Dafne; Alonso, Ricardo Narciso; Hinton, Richard; Edinburgh Ion Microprobe Facility Subduction zones, such as the Andean convergent margin of South America, are sites of active continental growth and crustal recycling. The composition of arc magmas, and therefore new continental crust, reflects variable contributions from mantle, crustal and subducted reservoirs. Temporal (Ma) and spatial (km) variations in these contributions to southern Central Andean arc magmas are investigated in relation to the changing plate geometry and geodynamic setting of the southern Central Andes (28–32 S) during the Cenozoic. The in-situ analysis of O and Hf isotopes in zircon, from both intrusive (granitoids) and extrusive (basaltic andesites to rhyolites) Late Cretaceous – Late Miocene arc magmatic rocks, combined with high resolution U–Pb dating, demonstrates distinct across-arc variations. Mantle-like d18O(zircon) values (+5.4& to +5.7& (±0.4 (2r))) and juvenile initial eHf(zircon) values (+8.3 (±0.8 (2r)) to +10.0 (±0.9 (2r))), combined with a lack of zircon inheritance suggests that the Late Cretaceous (73 Ma) to Eocene (39 Ma) granitoids emplaced in the Principal Cordillera of Chile formed from mantle-derived melts with very limited interaction with continental crustal material, therefore representing a sustained period of upper crustal growth. Late Eocene (36 Ma) to Early Miocene (17 Ma) volcanic arc rocks present in the Frontal Cordillera have ‘mantle-like’ d18O(zircon) values (+4.8& (±0.2 (2r) to +5.8& (±0.5 (2r))), but less radiogenic initial eHf(zircon) values (+1.0 (±1.1 (2r)) to +4.0 (±0.6 (2r))) providing evidence for mixing of mantle-derived melts with the Late Paleozoic – Early Mesozoic basement (up to 20%). The assimilation of both Late Paleozoic – Early Mesozoic Andean crust and a Grenville-aged basement is required to produce the higher than ‘mantle-like’ d18O(zircon) values (+5.5& (±0.6 (2r) to +7.2& (±0.4 (2r))) and unradiogenic, initial eHf(zircon) values (3.9 (±1.0 (2r)) to +1.6 (±4.4 (2r))), obtained for the Late Oligocene (23 Ma) to Late Miocene (9 Ma) magmatic rocks located in the Argentinean Precordillera, and the Late Miocene (6 Ma) volcanic rocks present in the Frontal Cordillera. The observed isotopic variability demonstrates that the assimilation of pre-existing continental crust, which varies in both age and composition over the Andean Cordillera, plays a dominant role in modifying the isotopic composition of Late Eocene to Late Miocene mantle-derived magmas, implying significant crustal recycling. The interaction of arc magmas with distinct basement terranes is controlled by the migration of the magmatic arc due to the changing geodynamic setting, as well as by the tectonic shortening and thickening of the Central Andean crust over the latter part of the Cenozoic.

Late Cenozoic contractional evolution of the current arc-volcanic region along the southern Central Andes (35°20′S) Tapia, Felipe; Farías, Marcelo; Naipauer, Maximiliano; Puratich, Jacqueline The Andean internal zone records deformation, uplift and erosion that serve as proxies of variations on mountain building dynamics. Hence, the study of this region would give keys to understand the factors controlling the orogenic evolution. Structural, stratigraphic and geochronological data in the Andean internal zone at 35°20′S evidence that this region has only underwent contractional deformation since the late Miocene up to present, differing from coeval Pleistocene extensional tectonics affecting the retro-arc. Contractional deformation was characterized by the development of a piggy-back basin in the latest Miocene filled by synorogenic deposits. Afterward, an out-of-sequence thrusting event affected the region since at least the Pliocene until the Present. Shortening in the inner part of the Andean orogen would be favored by both the high orthogonality of the out-sequence structures with respect to the plate convergence vector and by the minor resistance to shortening produced by the southward decrease of the orogen height and by the removal of material via erosion of the uplifted mountain belt. In contrast, oblique structures, as those described farther north, accommodate strike-slip displacement. Likewise, we propose that erosion from the inner orogen favored the prolongation of the out-of-sequence thrusting event until the Present, differing from the situation north of the 34°S where this event ended by the Pliocene.

Respuesta cardiovascular a la administración crónica de péptido natriurético tipo C en ratas espontáneamente hipertensas; Cardiovascular response to chronic administration of c-type natriuretic peptide in spontaneously hypertensive rats Caniffi, Carolina Cecilia; Sueiro, Laura; Bouchet, Gonzalo; Romero, Mariana; Barrionuevo, Emiliano; Arranz, Cristina Teresa; Costa, Maria de Los Angeles Introducción: El péptido natriurético tipo C (CNP) ha cobrado relevancia por sus efectos sobre la regulación de la función y la morfología del corazón y los vasos sanguíneos. Previamente demostramos in vitro que el CNP incrementa la actividad del sistema del óxido nítrico (NO) en ratas espontáneamente hipertensas (SHR). Objetivo: Estudiar el efecto del tratamiento crónico con CNP sobre la presión arterial sistólica (PAS), la función cardíaca y vascular y el sistema del NO en ratas espontáneamente hipertensas y normotensas. Material y métodos: Se emplearon ratas Wistar macho de 12 semanas de edad normotensas y espontáneamente hipertensas. Los animales recibieron infusión crónica de solución salina o CNP (0,75 mg/hora/rata) durante 14 días mediante la implantación de bombas osmóticas subcutáneas. Se midió la PAS y se realizaron un electrocardiograma y un ecocardiograma. Se extrajeron el ventrículo izquierdo y la arteria aorta torácica y se determinó la actividad, con L-[U14C]-arginina, de la óxido nítrico sintasa (NOS) y se realizaron estudios de reactividad vascular. Resultados: La administración crónica de CNP disminuyó la PAS en las SHR. Se observó menor volumen minuto en las SHR y el CNP incrementó dicho volumen, en tanto que no indujo cambios en las ratas normotensas. En las SHR se observó un desequilibrio en las respuestas vasodilatadora y vasoconstrictora en la arteria aorta y el tratamiento con CNP mejoró la función vascular respecto de las ratas normotensas. En ambos tejidos, la actividad de la NOS fue mayor en las SHR y se incrementó con la infusión durante 14 días de CNP. Sin embargo, dicho incremento fue menor en las SHR. Conclusión: El CNP induce cambios a nivel cardiovascular y en el sistema del NO que podrían resultar beneficiosos en este modelo de hipertensión arterial.; Background: C-type natriuretic peptide (CNP) plays an important role in the regulation of cardiovascular function and morphology. We have previously demonstrated that CNP increases nitric oxide (NO) system activity in vivo in spontaneously hypertensive rats (SHR). Objective: The goal of this study is to evaluate the effect of chronic CNP administration on systolic blood pressure (SBP), cardiovascular function and the NO system in spontaneously hypertensive and normotensive rats. Methods: Twelve-week-old normotensive male Wistar rats and SHR were used. They received chronic infusion of saline or CNP (0.75 mg/h/rat) for 14 days via subcutaneously implanted osmotic pumps. Systolic blood pressure was measured and an electrocardiogram and echocardiogram were performed. The left ventricle and the thoracic aorta were resected; nitric oxide synthase (NOS) activity was determined using L-[U14C]-arginine and vascular reactivity was assessed. Results: Chronic administration of CNP decreased SBP in SHR. Cardiac output was lower in SHR and increased with CNP; however, CNP had no effect in normotensive rats. Spontaneously hypertensive rats had unbalanced aortic vasodilation and vasoconstriction responses, and CNP improved the vascular function. Nitric oxide synthase activity was greater in SHR and increased with the 14-day CNP infusion, but this increase was lower than in normotensive rats. Conclusion: C-type natriuretic peptide induces cardiovascular and NO system changes which may be beneficial in this model of hypertension.

Pharmacological mechanism underlying the antinociceptive activity of vanillic acid Yrbas, Maria de Los Angeles; Morucci, Florencia; Alonso, Maria del Rosario; Gorzalczany, Susana Beatriz Vanillic acid is found at high concentrations in many plants used in traditional medicine. It has been associated with a variety of pharmacologic activities such as carcinogenesis inhibition, apoptosis and inflammation; however, it has become most popular for its pleasant creamy odor. Since there are few reports concerning the antinociceptive activity of this phenolic compound, the aim of this work was to study this activity in in vivo animal models. Vanillic acid was administered by the intraperitoneal route producing a dose-dependent inhibition of the acetic acid-induced writhing response (ED50: 9.3 mg/kg). The antinociceptive activity was inhibited by the pretreatment with ondansetron and yohimbine, indicating that the serotoninergic and adrenergic systems could participate in the mechanism underlying the analgesic activity of vanillic acid. This compound was also demonstrated to interact with ASICs (Acid-sensing Ion Channels) as well as with TPRV1, TRPA1, and TRPM8 receptors in vivo. Furthermore, vanillic acid did not interfere with the locomotor function or motor coordination. The plasmatic phenolic content, analyzed by HPLC, showed that its t1/2 and AUC were 0.123 h and 1.38 μg·h/mL; respectively. In conclusion, vanillic acid might represent a potential therapeutic option for the treatment of pain.

Influence of the projectile charge state on electron emission spectra from a Cu(111) surface Archubi, Claudio Darío; Silkin, V. M.; Gravielle, Maria Silvia Double differential electron emission distributions produced by grazing impact of fast dressed ions on a Cu(111) surface are investigated focusing on the effects of the electronic band structure. The process is described within the Band-Structure-Based approximation, which is a perturbative method that includes an accurate representation of the electron-surface interaction, incorporating information of the electronic band structure of the solid. Differences in the behaviour of the emission spectra for He+q, Li+q, Be+q and C+q projectiles with different charge states q are explained by the combined effect of the projectile trajectory and the projectile charge distribution.

Oil extraction kinetics of hydrothermally pretreated canola seeds Zárate, Valeria; Perez, Ethel; Crapiste, Guillermo Hector; Nolasco, Susana M.; Fernández, María Belén In this work the kinetics of oil extraction from spring canola seeds subjected to a hydrothermal pretreatment with direct steam (393 K, 5 min) was studied. The differences between the seed internal structure generated by the application of this pretreatment and that of the untreated sample (ground sample) were observed by scanning electron microscopy. Oil from both samples was extracted with hexane at different times and temperatures using a stirred batch system. Oil yield increased up to 46 % due to the hydrothermal treatment. A model was proposed to explain the oil extraction process from hydrothermally pretreated and untreated canola seeds, taking into account two main mechanisms: a washing process of the surface oil from the seed, and a diffusion process. Parameters of the model were fitted, and values of the oil fraction extracted during the washing step (0.27 and 0.50 for untreated and hydrothermally treated canola seeds, respectively) and the effective diffusion coefficient (3.1–9.4.10- 12 m2 s 1 ) were obtained. The latter value showed an Arrhenius-type temperature dependence in the untreated sample, but the diffusion coefficient did not vary with temperature when oil diffusion was analyzed using hydrothermally pretreated seeds.

Sobre la literatura de animales: apuntes para una crítica indisciplinada Yelin, Julieta Rebeca El trabajo tiene como objetivo inicial analizar algunas ideas nodales dentro del campo de los estudios animales para, a partir de esos lineamientos de carácter general, abordar el discurso de la crítica literaria, inmersa en un significativo proceso de reconfiguración conceptual. El acento será puesto sobre algunas apropiaciones de la noción de “vida”, un núcleo relevante en la mayor parte de los estudios críticos que examinan la productividad del vínculo literatura-animalidad. Dicho núcleo entraña una transformación de los juicios acerca de las formas que asumen las relaciones entre vida y literatura, así como también una revisión de las concepciones que intentan aprehender un sujeto de la experiencia.; O trabalho tem como objetivo inicial analisar algumas ideias nodais dentro do campo dos estudos animais para, a partir destas orientações de caráter geral, abordar o discurso da crítica literária, imersa em um significativo processo de reconfiguração conceitual. O acento será posto sobre algumas apropriações da noção de “vida”, um núcleo relevante na maior parte dos estudos críticos que examinam a produtividade do vínculo literatura-animalidade. Tal núcleo acarreta em uma transformação dos juízos acerca das formas que assumem as relações entre vida e literatura, assim como uma revisão das concepções que tentam apreender um objeto da experiência.; The work has as the initial objective to analyze some nodal points in the field of animal studies and, starting from these general guidelines, address the discourse of literary criticism undergoing a significant process of conceptual reconfiguration. The accent will be placed on some appropriations of the notion of "life", an important core in most critical studies examining the productivity of the literature-animality link. Suh core involves a transformation of the judgments about the forms taken by the relations between life and literature, as well as a revision of concepts trying to apprehend a subject of experience.

Physicochemical characterization of aqueous micellar systems formed by environmentally friendly salts Cordisco, Estefanía; Haidar, Carla; Goñi, Rocío; Nerli, Bibiana Beatriz; Pellegrini Malpiedi, Luciana In this work, environmentally friendly aqueous micellar two-phase systems containing nonionic surfactants (Triton X-114, Triton X-100 and Genapol X080) and organic salts (sodium citrate and sodium tartrate) were characterized. In order to accomplish this objective, the binodal diagrams (cloud point vs. surfactant concentration) were obtained for each condition. Additionally, critical micelle concentration (CMC) and micellar hydrodynamic diameter (DH) were determined for each system. According to the obtained results, it was found that the presence of salts lowered the CMC (ΔCMC up to 0.15 mM) and cloud point values (ΔCP up to 18 °C) following the sequence: sodium citrate > sodium tartrate. In addition, the hydrodynamic diameters of the micelles were notoriously increased in presence of the studied salts, showing the high sensitivity of the described aqueous micellar two-phase systems to the medium condition. These results open perspectives for the use of greener aqueous micellar two-phase systems for bioseparation purposes.

Carbohydrate metabolization in late stages in the recalcitrant pollen of pumpkin (Cucurbita pepo L.) Carrizo Garcia, Carolina; Guarnieri, M.; Pacini, E. Pumpkin (Cucurbita pepo L.) pollen is starchy, sucrose-poor and recalcitrant, features opposite to those of several model species; therefore, some differences in carbohydrate metabolism could be expected in this species. By studying pumpkin recalcitrant pollen, the objective was to provide new biochemical evidence to improve understanding of how carbohydrate metabolism might be involved in pollen functioning in advanced stages. Four stages were analysed: immature pollen from 1 day before anthesis, mature pollen, mature pollen exposed to the environment for 7 h, and pollen rehydrated in a culture medium. Pollen viability, water and carbohydrate content and activity of enzymes involved in carbohydrate metabolism were quantified in each stage. Pollen viability and water content dropped quickly after dehiscence, as expected. The slight changes in carbohydrate concentration and enzyme activity during pollen maturation contrast with major changes recorded with ageing and rehydration. Pumpkin pollen seems highly active and closely related to its surrounding environment in all the stages
analysed; the latter is particularly evident among insoluble sucrolytic enzymes, mainly wall-bound acid invertase, which would be the most relevant for sucrose cleavage. Each stage was characterised by a particular metabolic/enzymatic profile; some particular features, such as the minor changes during  maturation, fast sucrolysis upon rehydration or sharp decrease in insoluble sucrolytic activity with ageing seem to be related to the lack of dormancy and recalcitrant nature of pumpkin pollen.

A single ectomycorrhizal fungal species can enable a Pinus invasion Hayward, Jeremy; Horton, Thomas R.; Pauchard, Aníbal; Nuñez, Martin Andres Like all obligately ectomycorrhizal plants, pines require ectomycorrhizal fungal symbionts to complete their life cycle. Pines introduced into regions far from their native range are typically incompatible with local ectomycorrhizal fungi, and, when they invade, coinvade with fungi from their native range. While the identities and distributions of coinvasive fungal symbionts of pine invasions are poorly known, communities that have been studied are notably depauperate. However, it is not yet clear whether any number of fungal coinvaders is able to support a Pinaceae invasion, or whether very depauperate communities are unable to invade. Here, we ask whether there is evidence for a minimum species richness of fungal symbionts necessary to support a pine/ectomycorrhizal fungus coinvasion. We sampled a Pinus contorta invasion front near Coyhaique, Chile, using molecular barcoding to identify ectomycorrhizal fungi. We report that the site has a total richness of four species, and that many invasive trees appear to be supported by only a single ectomycorrhizal fungus, Suillus luteus. We conclude that a single ectomycorrhizal (ECM) fungus can suffice to enable a pine invasion.

Trifluoroacetic acid as excipient destabilizes melittin causing the selective aggregation of melittin within the centrin-melittin-trifluoroacetic acid complex Pastrana Rios, Belinda; Sosa, Liliana del Valle; Santiago, Jorge Trifluoroacetic acid (TFA) may be the cause of the bottleneck in high resolution structure determination for protein-peptide complexes. Fragment based drug design often involves the use of synthetic peptides which contain TFA (excipient). Our goal was to explore the effects of this excipient on a model complex: centrin-melittin-TFA. We performed Fourier transform infrared, two-dimensional infrared correlation spectroscopies and spectral simulations to analyze the amide I’/I’* band for the components and the ternary complex. Melittin (MLT) was observed to have increased helicity upon its interaction with centrin, followed by the thermally induced aggregation of MLT within the ternary complex in the TFA presence.

Indígenas y misioneros: génesis y representaciones de una misión evangélica en el ingenio La Esperanza; Indigenes and missionaries: genesis and representations of an evangelical mission in the sugar mill La Esperanza Espinosa, Mariana Esther En la primera década del siglo XX el misionero británico de los Hermanos Libres John Linton organizó una misión entre indígenas guaraníes -o “chiriguanos”- que se llamó Cherenta. El asentamiento se creó al interior de La Esperanza, el ingenio azucarero de la familia inglesa Leach ubicado en el piedemonte andino del noroeste argentino. El artículo busca desentrañar algunos aspectos sobre la génesis y las actuales representaciones de esta misión evangélica. En el fenómeno social que significa la misión confluyen al menos tres procesos con sus propias temporalidades y dinámicas: la etno-historia y etnografía sobre los grupos guaraní-hablantes; los ingenios azucareros, especialmente como espacios interétnicos; y las experiencias de misionalización. El trabajo se propone observar en estos ejes variables significativas que nos orienten hacia una interpretación del vínculo religión y etnicidad entre los actuales creyentes.; In the first decade of the twentieth century the British missionary John Linton of the Free Brethren organized a mission among “chiriguanos” indigenes called "Cherenta". The establishment was built within La Esperanza, the sugar mill of the British Leach family located in the Andean foothills in Argentine northwestern. The article seeks to reveal some aspects of the genesis and current representations of this evangelical mission. In the social phenomenon that means the mission converge at least three processes with their own temporality and dynamic: the ethno-history and ethnography of the “chiriguanos”; sugar mills, especially as interethnic spaces; and the experiences of misionalization. The paper aims to observe significant variables into these axes to guide us towards an interpretation of the link between religion and ethnicity of the believers at the present time.

¿A qué jugabas en la escuela? Galak, Eduardo Cuando Carolina y Noélia me invitaron a responder la pregunta por "¿A qué jugabas en la escuela?" no puede dejar de pensar en una imagen que se me apareció en mis pensamientos: grupos de niños y niñas, con sus blancos guardapolvos, jugando en un patio escolar de grises baldosas separadas por gruesos trazos negros que daban la impresión de una gran cuadricula que sería geométricamente perfecta si no fuera por un mástil que la interrumpía, portando una bandera casi inmóvil, porque ese monumento de cemento estaba en el centro de cuatro paredes que marcaban el afuera del patio y el adentro de las aulas. Estos niños que se me aparecen como imágenes borrosas jugaban por todo este espacio, en grupos reducidos, con alguna pelota sacada de uno vaya a saber dónde, pero se sabía bien para qué (nadie amagó en mis recuerdos a proponer otra cosa que no sea patearla), o con un elástico para el caso de las niñas o de niños desinteresados en correr atrás de una pelota (o en ser criticados por "jugar mal", lo suficiente como para ni siquiera merecer el arco sin ser igualmente criticados), elásticos de esos blancos que dividen los adentros, los afueras y los encimas coreografiados por músicas infantiles repetidas mecánicamente por quienes tienen la responsabilidad de sostenerlo y de denunciar quien cometió una equivocación.

Glucan particles loaded with a NIRF agent for imaging monocytes/macrophages recruitment in a mouse model of rheumatoid arthritis Garello, Francesca; Arena, Francesca; Cutrin, Juan Carlos; Esposito, Giovanna; D'angeli, Luca; Cesano, Federico; Filippi, Miriam; Figueiredo, Sara; Terreno, Enzo Glucan Particles (GPs) are hollow pseudo-microspheres (average diameter 3?5 mm) obtained from common baker´s yeast Saccharomyces cerevisiae, in which mannan, lipids and proteins are removed through a process of chemical extraction. GPs shell is mostly made of 1,3-b-D-glucan that allows for their prompt in vivo uptake by immune system cells. In this work, the inner cavity of the particles has been loaded with two amphiphilic fluorescent dyes (based on cyanine for in vivo imaging purposes and rhodamine for ex vivo microscopy experiments) through a sudden change in solvent polarity that allowed the entrapment of the molecules as microemulsion. The ability of fluorescent GPs to label immune cells in vivo and report on their recruitment in inflamed sites has been successfully demonstrated in a mouse model of rheumatoid arthritis (CIA) by NIRF imaging. Besides providing the visualization of the mononuclear cell infiltration in the lesion, the fluorescent signal well correlated with the clinical score associated with the disease. Very interestingly, the signal detected in lesions with the same clinical score allowed the assessment of the time evolution (progression or remission) of the pathology.

A Nitric Oxide-Donor Furoxan Moiety Improves the Efficacy of Edaravone against Early Renal Dysfunction and Injury Evoked by Ischemia/Reperfusion Chiazza, Fausto; Chegaev, Konstantin; Rogazzo, Mara; Cutrin, Juan Carlos; Beneti, Elisa; Lazzarato, Loretta; Fruttero, Roberta; Collino, Massimo Edaravone (5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one, EDV) is a free-radical scavenger reduces organ ischemic injury. Here we investigated whether the protective effects of EDV in renal ischemia/reperfusion (I/R) injury may be enhanced by an EDV derivative bearing a nitric oxide- (NO-) donor furoxan moiety (NO-EDV). Male Wistar rats were subjected to renal ischemia (45 minutes), followed by reperfusion (6 hours). Administration of either EDV (1.2–6–30 µmol/kg, i.v.) or NO-EDV (0.3–1.2–6 µmol/kg, i.v.) dose-dependently attenuated markers of renal dysfunction (serum urea and creatinine, creatinine clearance, urine flow, urinary N-acetyl-β-D-glucosaminidase, and neutrophil gelatinase-associated lipocalin/lipocalin-2). NO-EDV exerted protective effects in the dose-range 1.2–6 µmol/kg, while a higher dose (30 µmol/kg) was needed to obtain protection by EDV. Both EDV and NO-EDV modulated tissue markers of oxidative stress and lipid peroxidation. NO-EDV, but not EDV, activated endothelial NO synthase (NOS) and blunted I/R-induced upregulation of inducible NOS, secondary to modulation of Akt and NF-κB activation, respectively. Besides NO-EDV administration inhibited I/R-induced IL-1β, IL-18, IL-6, and TNF-α overproduction. Overall, these findings demonstrate that the NO-donor moiety contributes to the protection against early renal I/R injury and suggest that NO-donor EDV codrugs are worthy of additional study as innovative pharmacological tools.

Thermoresponsive hydrogels based on alginate-g-poly(N-isopropylacrylamide) copolymers obtained by low dosis of gamma radiation Lencina, María Malvina Soledad; Ciolino, Andrés Eduardo; Andreucetti, Noemi Amalia; Villar, Marcelo Armando Low doses of gamma radiation from 60Co have been used in the synthesis of water soluble alginate-g-poly(N-isopropylacrylamide) (PNIPAAm) copolymers. Irradiation was carried out using glass vials containing aqueous solutions of alginate and NIPAAm monomers. The resulting copolymers have been characterized by different characterization techniques such as Fourier transform infrared spectra, 1H Nuclear Magnetic Resonance, elemental analysis and thermogravimetric analysis. NIPAAm concentration in the initial reaction mixture and irradiation dose evidenced a direct effect on the grafting percentage; an increasing in NIPAAm concentration in the initial reaction mixture always led to a higher content of grafted PNIPAAm in the copolymers. On the other hand, for a fixed NIPAAm concentration in the reaction mixture, the amount of PNIPAAm in the copolymer increased with the dose. Copolymers were used in hydrogels formation by cross-linking alginate carboxylic groups with Ca2+and swelling properties of the new materials were studied at 24 °C and 37 °C. Hydrogels presented thermo-sensitivity, showing lower swelling ratios at 37 °C. Hydrogel water uptake was hindered as a consequence of the collapsed state of PNIPAAm moieties in the copolymers.

Proliferation of effective interactions: Decoherence-induced equilibration in a closed many-body system Zangara, Pablo René; Bendersky, Denise; Pastawski, Horacio Miguel We address the question of how weak perturbations, which are quite ineffective in small many-body systems, can lead to decoherence and hence to irreversibility when they proliferate as the system size increases. This question is at the heart of solid-state NMR. There, an initially local polarization spreads all over due to spin-spin interactions that conserve the total spin projection, leading to an equilibration of the polarization. In principle, this quantum dynamics can be reversed by changing the sign of the Hamiltonian. However, the reversal is usually perturbed by nonreversible interactions that act as a decoherence source. The fraction of the local excitation recovered defines the Loschmidt echo (LE), here evaluated in a series of closed N spin systems with all-to-all interactions. The most remarkable regime of the LE decay occurs when the perturbation induces proliferated effective interactions. We show that if this perturbation exceeds some lower bound, the decay is ruled by an effective Fermi golden rule (FGR). Such a lower bound shrinks as N increases, becoming the leading mechanism for LE decay in the thermodynamic limit. Once the polarization stayed equilibrated longer than the FGR time, it remains equilibrated in spite of the reversal procedure.

Robust Estimators for Data Reconciliation Llanos, Claudia Elizabeth; Sanchez, Mabel Cristina; Maronna, Ricardo Antonio In this work, a comparative performance analysis of robust data reconciliation strategies is presented. The study involves two procedures based on the biweight function and three estimation techniques that use the Welsh, quasi-weighted least squares, and correntropy M-estimators. The aforementioned functions are selected for comparative purposes because their use in the data reconciliation literature has appeared during the past decade. All procedures are properly tuned to have the same estimation and gross error detection/identification capabilities under the ideal distribution. Different measurement models are systematically taken into account, and results are analyzed considering both performance measures (average number of type I errors, global performance, mean square error) and computational load. The comparative analysis indicates that a simple robust methodology can provide a good balance between those two issues for linear and nonlinear benchmarks.

The mathematics teacher’s profession: the perspective of future Corica, Ana Rosa; Otero, Maria Rita We present partial results of the design and implementation of a study program for the Mathematics Teacher Training. The research is developed in the light of the Anthropological Theory of the Didactic. This paper we analyze what gestures of the research and world questioning pedagogy are identified in a group of future teachers that study an essential issue to the mathematics teacher profession: how to teach mathematical knowledge? The work was carried out with futures mathematics teachers of the third year of a careen university in Argentina. The main results indicate that the future teachers, at the beginning of the study program, do not seem to carry out the distinctive didactics gestures of the research and questioning the world pedagogy.

Oleanolic acid: a promising neuroprotective agent for cerebral ischemia Caltana, Laura Romina; Nieto, Maria Luisa; Brusco, Herminia Alicia Stroke is considered the most common and severely disabling neurologicaldisease. It is one of the leading causes of death after heartdisease and cancer, causing 10% deaths worldwide and involvingrisk factors such as smoking, obesity and nutritional disbalance.Disability affects 75% of stroke survivors through severe mentaland/or physical impairment depending on the affected brain area(Go et al., 2014).Stroke treatment is limited to thrombolysis and antiplatelettherapy with a tissue plasminogen activator (tPA), which is onlyuseful if administered within 3 hours of the appearance of earlysymptoms. This therapy is only used in 1?2% stroke patients andhas, indeed, limited clinical success, as it does not protect neuronsfrom the hypoxic insult. Therefore, the development and evaluationof new drugs to reduce the life-threatening effects of strokeand hypoxia might prove extremely fruitful.Stroke is produced by a decrease in blood supply due to differenttypes of alterations in the brain blood vessels, which cause cerebralhypoxia/ischemia. In turn, the hypoxic damage produces severalchanges in gene expression patterns in brain tissue cells (neuronsand glial cells). Rapid thrombolysis is effective in protecting theinjured ischemic core, although preventing the pathological featuresthat produce neuronal death requires the development of newtreatments and the implementation of a dual therapy combiningthe disruption of the clot and the preservation of neuronal function.In this respect, many preclinical studies have been successfulin finding neuroprotective agents, but subsequent clinical trialshave rendered disappointing results.Inflammation is one of the distinctive events in stroke, whilemicroglial cells are the predominant inflammatory effectors inbrain. Reactive astrocytosis and the formation of a glial scar in theboundary zone of the ischemic core are also critical events whichcan produce both positive and negative consequences.