"Un cóndor de fuego marchando hacia los cielos infinitos". Cuatro proposiciones sobre el viaje reformista Bergel, Martin Este ensayo recorta analíticamente una zona de la praxis intelectual y cultural del reformismo universitario del período 1918-1930 a la que se denomina viaje reformista. Con el propósito de reconstruirla, se abordan cuatro dimensiones: su rol como dispositivo activador de procesos de movilización estudiantil en ambientes distantes; la secuencia de desplazamientos y actuaciones en conferencias y actos públicos de los líderes del movimiento reformista, y las dimensiones rituales y performáticas que se ponían en escena en esas ocasiones; el lugar del americanismo como ingrediente imaginario que obraba impulsando este tipo de travesías, y sus solapamientos y posteriores deslindes con el horizonte internacionalista y universalista más vasto que tenía importante presencia en el período; y, finalmente, el carácter polémico y agonal de este tipo de viajes en relación a otras tentativas de fraternidad americana del período, en especial las impulsadas por diplomáticos y políticos.; This essay analytically dissects an area of University Reformism’s intellectual and cultural praxis during 1918-1930 here termed Reformist Journey. In order to reconstruct it, four dimensions are approached: its role as activating device of student mobilization processes in distant environments; the sequence of displacements and performances in conferences and public events of the leaders of the reformist movement, and the ritual and performative dimensions staged at those times; the function of Americanism as an imaginary ingredient promoting these journeys, and its links to the wider internationalist and universalist horizon, whose presence was significant then; and, finally, the controversial and agonal character of this sort of traveling in relation to other attempts of American fraternity of the period, especially those encouraged by diplomats and politicians.

Uptake and release of Dexamethasone using pH-responsive poly (2-hydroxyethyl methacrylate-co-2-(diisopropylamino) ethyl methacrylate) hydrogels for potential use in ocular drug delivery Faccia, Paula Andrea; Pardini, Francisco Martín; Amalvy, Javier pH-responsive hydrogels prepared by copolymerization between 2-hydroxyethyl methacrylate (HEMA) and 2-(diisopropylamino)ethyl methacrylate (DPA) appear to be a promising system for controlling Dexamethasone 21-disodium phosphate (DXP) release behaviors for ophthalmological treatments. The incorporation and subsequent release of DXP by HEMA-DPA copolymers have been evaluated in different pH mediums and in vitro conditions. Optical and morphological characteristics, as well as wettability, drug-matrix interactions and drug-release properties, were assessed. Drug incorporation was maximum at pH 6.5 and at an initial drug concentration of 200 mg/L. Additionally, increasing the DPA content and cross-linker ratio increased the amount of loaded DXP. The amount of DXP released was approximately 70%, and the entire release process took 20–40 h. Moreover, the copolymers showed changes in the release rate in response to small pH variations (between 7.0 and 7.8). Additionally, DXP release by the copolymers far exceeded the estimated concentration of the drug absorbed in the eyes by drop administration.

Acid hydrogel matrixes as reducing/stabilizing agent for the in-situ synthesis of Ag-nanocomposites by UV irradiation: PH effect Broglia, Martin Federico; Balmaceda, Ivana; Carrizo, Florencia; Barbero, César Alfredo; Rivarola, Claudia Rosana Synthetic methods to obtain Ag-nanocomposites are widely studied in order to produce antimicrobialmaterials without using harmful agents for possible applications in biologic systems. In this way, thenanocomposites could be able to apply in biomedicine area avoiding going through exhaustiveprocesses of purification. Biocompatible hydrogel based on N-isopropylacrylamide (NIPAM)copolymerized with different proportions of methacrylic acid (MAA) and 2-acrylamido-2-methylpropanesulfonic acid (AMPS), were proposed as matrixes of Ag-nanocomposites. A comprehensive studyof the physicochemical behavior, reducing and stabilizing character of the matrixes were carried out atpH 2 and 7. Hydrogel nanopores were used as photoreducing of Ag+ ions and stabilizing of Agnanoparticles(Ag-NPs) at the same time. Most of the matrixes showed high reducing character atpH 7 while at pH 2 it was significantly reduced. Photoreducer character at pH 7 increased with MAAco-monomer concentration and Ag-NPs sizes of 4?5 nm were obtained. In addition, it wasdemonstrated that acidic co-monomers favor the stabilization of Ag-NPs avoiding agglomerations. Itwas possible to conclude that the photoreduction reaction takes mainly place at pH 7 when nonbonding electron pairs from carboxylic and amide groups of the matrix are available. Therefore,biocompatible and antimicrobial nanocomposites can be easily synthesized without using damagingadditives(reducer, solvent) and be applied in biomedicine.

La mujer natural: la influencia de Charles Baudelaire en "L'automne à Pekin" de Boris Vian; The natural woman: the influence of charles baudelaire in boris vian's l'automne à Pékin de Cabo, Mariana; Montecchio, Estefanía Silvia En un epígrafe de L’automne à Pekin (1947), Vian cita un fragmento de Fusées de Baudelaire: «Aimer une femme intelligente est un plaisir de pédéraste». En la cosmovisión de Baudelaire, la mujer, ser puramente natural, conduce al hombre a sus más bajos instintos y, en consecuencia, al mal. Por eso, la relación amorosa con el sexo femenino representa un acto sádico y primitivo entre una víctima y un victimario. Nos proponemos analizar, a partir del estudio de la concepción baudelairiana de la mujer, por qué Vian cita al escritor del siglo XIX y en qué medida este intertexto le permite moldear en su novela una presunta visión estereotipada del género femenino.; In an epigraph from L’automne à Pékin (1947), Vian quotes a passage from Baudelaire's Fusées: «Aimer une femme intelligente est un plaisir de pédéraste». In Baudelaire's world view, the woman, a purely natural being, guides the man to his lowest instincts and, therefore, to evil. For that reason, the loving relationship with female represents a sadistic and primitive act between a victim and a killer. Our aim is to analyze, based on the baudelairean conception of women, the motive why Vian quotes the XIXth century writer and how much this intertext allows Vian to shape in his novel a presumed stereotyped vision of the feminine gender.

Role and management of soil biodiversity for food security and nutrition; where do we stand? El Mujtar, Verónica Andrea; Muñoz, Nacira Belén; Prack Mc Cormick, Bárbara Patricia; Pulleman, Mirjam; Tittonell, Pablo Soils host diverse communities that support and regulate ecosystem functions, thereby affecting plant production and resource use efficiencies. There is increasing evidence that agricultural intensification affects soil biodiversity (SBD) and such changes may impact on current and future food security. Here, we provide an overview of the state-of-the-art on the relations between agricultural management, SBD and food production. The potential of applying such knowledge to improve food security and nutrition is discussed. Biotechnological methods to describe impacts of agricultural practices on taxonomic and functional diversity of soil organisms are advancing rapidly. At the same time new understanding of soil-plant interactions has provided novel insights into the mechanisms by which soil organisms and plants co-regulate plant growth and defences, or affect food nutritional quality and safety. Yet, empirical studies on SBD – plant productivity relations often lead to results and applications that are crop and context specific. Translating knowledge on SBD into universally applicable soil management recommendations to enhance food production, and ultimately food security, remains challenging. Instead, we propose a holistic approach to SBD management that strengthens multiple ecosystem functions and provides ecological insurance.

Dynamic capabilities in the software and information services industry. A case-study analysis in Argentina from a business model perspective Obaya, Martín; Robert, Veronica; Lerena, Octavio; Yoguel, Gabriel Leopoldo This study explores the relation between the strategies and business models (BM) configurations and the capability-augmenting efforts pursued software and information services (SIS). Through a multiple case-study research design, examining four SIS firms operating in Argentina, it seeks to understand, in particular, the nature of the dynamic capabilities (DC) developed by these firms, i.e. their ability to integrate, reconfigure and enlarge their base of strategic resources and ordinary capabilities. The findings of the study shed light on the two-way relation between the components of the BM and the nature DC. In the case of standardized product-oriented strategies, firms privilege integrating ‘sense’ DC to grasp market’s needs and demands with ‘seize’ DC to develop products able to exploit commercialization opportunities. In service-oriented strategies, ‘sense’ DC are focused on the identification of the features among the wide variety of customers’ demands which are scalable. Whereas ‘seize’ DC are rather focused on project management skills to integrate the architectures and accumulated reusable pieces of codes with capabilities to continuous improvement processes.

Bodies in the tip: Deaths and politicised deaths in Buenos Aires's refuse Perelman, Mariano Daniel The appearance of corpses in rubbish tips is not a recent phenomenon. In Argentina, tips have served not only as sites for the disposal of bodies but also as murder scenes. Many of these other bodies found in such places belong to individuals who have suered violent deaths, which go on to become public issues, or else are ‘politicised deaths’. Focusing on two cases that have received diering degrees of social, political and media attention – Diego Duarte, a 15-year-old boy from a poor background who went waste-picking on an open dump and never came back, and Ángeles Rawson, a girl of 16 murdered in the middle-class neighbourhood of Colegiales, whose body was found in the same tip – this article deals with the social meanings of bodies that appear in landlls. In each case, there followed a series of events that placed a certain construction on the death – and, more importantly, the life – of the victim. Corpses, once recognised, become people, and through this process they are given new life. It is my contention that bodies in rubbish tips express – and congure – not only the limits of the social but also, in some cases, the limits of the human itse

Entre la educación estatal y la privada: el dilema ideológico del judeo-progresismo argentino (1955-1995); Between State and Private Education: the Ideological Dilemma of Argentine Progressive Jews (1955-1995) Visacovsky, Saba Nerina El presente artículo reconstruye un dilema político-educativo que atravesó a los judíos progresistas argentinos adheridos al Idisher Cultur Farband o ICUF (Federación de Entidades Culturales Judías), entre 1955 y 1995. Los «icufistas» (de ahora en más), cercanos al Partido Comunista, defendieron con vehemencia los principios de la educación laica, gratuita y obligatoria plasmada en la Ley 1420 (1884), y los postulados de autonomía, co-gobierno y libertad de cátedra de la Reforma Universitaria (1918). En 1958, frente al conflicto «laica o libre», que polarizó a la ciudadanía entre quienes defendían una educación privada-confesional y quienes abogaban por la exclusividad de un estado laico educador, los icufistas se manifestaron activamente junto a estos últimos. Paralelamente a ello, sostenían una red de escuelas idiomáticas en ídish (shules) fundadas por los inmigrantes, que cumplían un rol «complementario» y fueron declinando hacia la década del sesenta. Para salvarlas había que convertirlas en escuelas integrales privadas de tiempo completo, pero aquello iba en contra de sus principios a favor de una educación pública e igualitaria. En el IX° Congreso del ICUF, en 1968, los delegados de todo el país votaron a favor de seguir con los shules hasta donde se pudiera, pero no competir con la escuela estatal. Sin embargo, en los noventa, dos décadas más tarde, el ICUF acompañó la apertura de una escuela laica privada en una de sus instituciones; ¿qué transformaciones sociales y políticas generaron este cambio?, ¿cómo lograron compatibilizar un discurso a favor de la educación estatal y el desarrollo de una escuela privada? Basado en un extenso trabajo de investigación, este artículo analiza, a la luz del contexto nacional e internacional, los dilemas educativos de ese colectivo judeo-progresista, identificado con los sectores medios argentinos.; This article reconstructs a political-educational dilemma that plagued the progressive Argentine Jews of the Yiddisher Kultur Farband (YKUF), or Federation of Jewish Cultural Entities (from now on, «the Ykufists»), between 1955 and 1995. Ideologically close to the Communists, they defended the secular, gratuitous and compulsory education principles embodied in Law 1420 (1884), and the postulates of autonomy, co-government and freedom of University Reform (1918). In 1958, faced with the «secular or free» conflict, which polarized the citizenship between those who defended a private-confessional education and those who advocated the exclusiveness of a secular state education, the Ykufists actively demonstrated their affinity with the latter. Parallel to this, they supported a network of idiomatic schools in Yiddish (shules), founded by immigrants, which played a «complementary» role. These shules declined towards the 1960s. To save them, they had to be turned into full-time private schools, but that would go against their principles in favour of a public and egalitarian education. At the 9th YKUF Congress in 1968, delegates from all over the country voted to continue with the shules for as long as possible, but not to compete with the state school. However, two decades later, in the nineties, YKUF was happy for a private secular school to be opened in one of its institutions; what social and political transformations generated this change? How did they manage to reconcile a discourse in favour of state education and then green light a private school? Based on extensive research, this article analyses, in light of the national and international context, the educational dilemmas of this progressive Jewish group, which identified with the Argentine middle classes.

Acacia caven gum studies of hydrodynamic parameters Tonelli, Franco; Masuelli, Martin Alberto The acacia caven gum (ACG) is an exudate from Acacia caven tree, this gum is dissolved in water and purified by precipitation with ethanol. In this paper the intrinsic viscosity, [η], is calculated by dissimilar equations, as Huggins, Kramer, Arrhenius-Rother-Hoffmann, Staudinger & Heuer, Square (S), Square root (SR), S-SR average plot, average values of S-SR, and being Kraemer is taken as standard. The different methods are evaluated and compared. From [η] measurements are determined the molecular weight (MV) and hydrodynamic radius (RH), with values of 1060 Kg/mol and 24 nm, respectively. This polysaccharide acquires a random coil conformation with Mark-Houwink parameters of a=0.5507 and k=0.0225 cm3/g. This polysaccharide is applied as thickener, coemulsifier and gelling in different industry.

"Para no estar sin hacer nada": formación para la inserción laboral de personas inmigrantes en Barcelona; “To not be doing nothing”: labour market training for immigrants in Barcelona Yufra, Laura Cristina; Santamaría Lorenzo, Enrique En este artículo nos hemos propuesto analizar las políticas de formación que se dirigen a la inserción laboral de las personas inmigrantes en la ciudad de Barcelona. Sirviéndonos de la propuesta de Chris Shore y Susan Wright (1997) de llevar a cabo una antropología de las políticas, hemos podido reconocer la explicitación de las características ideales que se espera que presenten las personas inmigrantes. Es decir, hemos podido identificar la recurrente solicitud de atenuación o de eliminación de las particularidades culturales, que supuestamente inciden de manera negativa en su inserción laboral, así como también, la recomendación de que se muestren siempre activos en la búsqueda de empleo. De igual modo, hemos podido reconocer los procesos de descalificación de los saberes de las personas inmigrantes y su consecuente “inclusión diferencial” en el segmentado mercado de trabajo; In this article we have proposed to analyse the training policies aimed at labour market integration for immigrants in the city of Barcelona. Making use of the proposal by Chris Shore and Susan Wright (1997) to develop an anthropology of policy, we have identified the specifications of the ideal characteristics that immigrants are expected to display. In other words, we have identified recurring requests for attenuation or elimination of cultural particularities, which supposedly have a negative impact on labour market integration, as well as the recommendation that immigrants always show themselves to be actively seeking work. We have also recognised processes involving downgrading of the knowledge that immigrants have and their consequent “differential inclusion” in the segmented labour market.

Non-monetary indicators to monitor SDG targets 1.2 and 1.4: standards, availability, comparability and quality Santos, Maria Emma This report offers a review of 14 non-monetary indicators of poverty to monitor progress towards the first Sustainable Development Goal (SDG) “End poverty in all its forms everywhere”. The reviewed indicators are housing materials, overcrowding, housing tenure, durable goods, access to safe water and improved sanitation, access to clean sources of energy, garbage collection and nearby sources of contamination, (public) transportation, child attendance to school and adult schooling, employment, social security and access to health care. For each of these indicators the study offers (a) short motivation about the capacity to “capture the essence” of some dimension of poverty, (b) a review of the indicator’s most prevalent specification/s and an indication of the minimum international standard – if there is one – for a satisfactory achievement, (c) a general assessment of current data availability, considering the most prominent standardised household surveys across the world, and (d) discussion and recommendations on each indicator’s specification and standard to be used homogeneously across countries. Two overarching messages from this report are: (1) that it is important to continue building international consensus regarding the desirable minimum thresholds and (2) that there is still room and need for significant improvements in data collection.

A new species of Eptesicus (Chiroptera, Vespertilionidae) from Argentina Sánchez, Rocío Tatiana; Montani, María Eugenia; Tomasco Introini, Ivanna Haydée; Díaz, María Mónica; Barquez, Ruben Marcos En Sudamérica se distribuyen ocho especies de murciélagos del género Eptesicus de las cuales cuatro están presentes en Argentina. Aquí describimos una nueva especie de este género sobre la base de ejemplares procedentes de la provincia de La Rioja y un ejemplar de la provincia de Mendoza, Argentina, depositado en una colección de museo. Esta nueva especie se distingue de las otras especies del género Eptesicus por su coloración dorada a marrón amarillenta, por el fuerte contraste entre la coloración dorsal y la ventral, el antebrazo grande (> 41 mm) y el pelaje dorsal relativamente corto (~6 mm). Se incluye una descripción detallada de la morfología externa y craneal de la nueva especie y se compara con especies de tamaño similar y presentes en el área de distribución. Se realizó una prueba de Wilcoxon-Mann-Whitney y un Análisis de Función Lineal Discriminante, con el objetivo de evaluar las diferencias morfométricas entre las especies de Eptesicus. Las filogenias obtenidas por diferentes criterios y con el uso de diferentes genes son coincidentes en cuanto a las relaciones de la nueva especie.; Eight species of the bat genus Eptesicus are distributed in South America of which four are known from Argentina. Here, we describe a new species, based on specimens collected from La Rioja Province, and one specimen from Mendoza Province, Argentina, deposited in a museum collection. This new species of Eptesicus can be distinguished from other congeners by its golden to yellowish-brown coloration, strong contrast between dorsal and ventral fur color, long forearm (> 41 mm), and by the relatively short (~ 6 mm) dorsal fur. A detailed description of the external and cranial morphology of the new species, as well as comparisons with other species of similar size, and present in the same distributional area, are included. A Wilcoxon–Mann–Whitney test and a discriminant linear function analysis were performed to assess the morphometric differences among species of Eptesicus. The phylogenies obtained by different criteria, as well as those obtained independently from different genes, are in agreement with regard to the relationships of the new species.

Fossils reveal long-term continuous and parallel innovation in the sacro-caudo-pelvic complex of the highly aquatic pipid frogs Gomez, Raul Orencio; Pérez Ben, Celeste Marina Within the already peculiar Bauplan of anurans, pipid frogs have evolved an array of bizarre features that are commonly linked to their highly aquatic lifestyle. Among the latter, there are several distinctive sacro-caudo-pelvic features shared by extant pipids, which have been regarded as evolutionary novelties taking part of a specialized fore-aft-sliding ilio-sacral joint. Pipids and their kin (pipimorphs) have a rich fossil record documenting 130 million years of uninterrupted evolution in aquatic environments, which, along with our current understanding of their phylogeny and recently available musculoskeletal data, allows us to inquire on the patterns and processes that have led to their distinctive sacro-caudo-pelvic system with a deep-time perspective. Here, we take a phylomorphospace approach based on discrete character matrices and a scaffold tree derived from recent studies, making comparisons of morphospace occupation between pipids and other anurans, and morphospace occupation, disparity, levels of homoplasy, and shared evolving characters between different groups and/or over time across pipimorphs. In doing so, we focus on trends of morphological diversification and discuss the potential role that ecological and developmental constraints might have had in driving the evolution of the sacro-caudo-pelvic complex of pipid frogs. Our main findings reveal a pattern of continuous and parallel innovation early in the history of pipids, followed by arrested evolution of novel morphologies toward the Recent. The latter, in turn, is mirrored by rampant homoplasy in the ilio-sacral sliding joint among extant pipid frogs. This study highlights the importance of fossils in revealing macroevolutionary patterns that will be otherwise veiled based on neontological data alone.

Physiological maturity as a function of seed and pod water concentration in spring rapeseed (Brassica napus L.) Menendez, Yesica Cristina; Botto, Javier Francisco; Gomez, Nora V.; Miralles, Daniel Julio; Rondanini, Deborah Paola Determining the optimum time for rapeseed harvest is challenging due to non-uniform seed maturity resulting from asynchronous flowering and pod dehiscence from sequential racemes. Identifying physiological maturity (PM) by visual methods is subjective and results can be affected by environmental conditions. PM can be determined using a quantitative model based on seed water concentration (SWC) as previously demonstrated for several other crops, although not yet developed for rapeseed crop. The objective of this work was to study the relationship between the dynamics of seed dry weight and water concentration in seven spring rapeseed cultivars grown at two contrasting densities (15 and 60 pl m−2) in three experiments at one location in Buenos Aires (Argentina). We evaluated the timing of PM on the basis of SWC in seeds located in the main raceme, second and fourth floral branches. The evolution of seed fresh and dry weight was followed bi-weekly from the beginning of flowering to harvest maturity. In Exp. 1, the grain-filling duration ranged from 39 to 57 days (700–1100 °C d) and the growth of seeds from floral branches finished 3–8 days later than those from the main raceme. Seed dry weight at PM ranged from 2.4 to 2.7 and from 3.0 to 3.2 mg for Lynx and Monty cultivars, respectively, without significant effects of floral position or plant density. Bi-linear functions were used to fit the relationship between relative seed dry weight (RSDW) and SWC relationships (R2 from 0.85 to 0.95). Across cultivars and floral positions, PM was attained when seeds exhibited 46.3 ± 0.7% SWC (R2 = 0.90, P < 0.001, n = 441). This model was validated against independent data from Exps. 2 and 3, successfully simulating the dynamics of relative seed dry weight based on fruit WC (r = 0.88; P < 0.001, n = 275). At PM, the water content (WC) of whole pod was about 70% and the pod shattering began after this point, when the WC of the pod dropped drastically. We conclude that under non-stressful conditions, PM in rapeseed occurs at 46% SWC. Swathing can be conducted from SWC < 46%, instead of the currently recommended 35%, advancing the harvest and leaving the land available for sowing the next crop, which would represent an advantage for double cropping in intensified agricultural systems.

Impact of HIV-ART on the restoration of Th17 and Treg cells in blood and female genital mucosa Caruso, María Paula; Falivene, Juliana; Holgado, María Pía; Zurita, Diego Hernán(EXT); Laufer, Natalia Lorna; Castro, Carina Lorena; Nico, Ángeles; Maeto, Cynthia Alejandra; Salido, Jimena Patricia; Perez, Hector; Acevedo González, Horacio Anselmo; Cahn, Pedro; Sued, Omar Gustavo; Fink, Valeria Irene; Turk, Gabriela Julia Ana; Gherardi, Maria Magdalena The aim of this study was to evaluate the effectiveness of antiretroviral treatment (ART) on the proportion and functions of Th17 and Treg cells in peripheral blood and female genital tract (FGT) respectively. To this aim, samples from 41 HIV-neg, 33 HIV+ ART-naïve and 32 HIV+ ART+ subjects were obtained. In peripheral blood, altered Th17 and Th17/Treg proportions were normalized in HIV+ ART+, but certain abnormal Treg and activated T-cell proportions were still observed. In FGT, abnormal patterns of secretion for Th17-related cytokines were observed in cervical mononuclear cells (CMCs) from HIV+ women, even in those from HIV+ ART+, compared to the HIV-neg group. Moreover, these altered patterns of secretion were associated with diminished levels of CXCL5 and CXCL1 chemokines and with an immunoregulatory skew in the CCL17/CCL20 ratio in ectocervix samples of these women. Finally, ART did not restore proportions of Th17-precursor cells with gut-homing potential in PBMCs, and positive correlations between these cells and the levels of IL-17F and IL-21 production by CMCs may suggest that a better homing of these cells to the intestine could also imply a better restoration of these cells in the female genital tract. These results indicate that antiretroviral treatment did not restore Th17-related immune functions completely at the female mucosal level.

Joint species movement modeling: How do traits influence movements? Ovaskainen, Otso; Leal Ramos, Danielle; Slade, Eleanor; Merckx, Thomas; Tikhonov, Gleb; Pennanen, Juho; Pizo, Marco Aurélio; Ribeiro, Milton Cezar; Morales, Juan Manuel Joint species distribution modeling has enabled researchers to move from species‐level to community‐level analyses, leading to statistically more efficient and ecologically more informative use of data. Here, we propose joint species movement modeling (JSMM) as an analogous approach that enables inferring both species‐ and community‐level movement parameters from multispecies movement data. The species‐level movement parameters are modeled as a function of species traits and phylogenetic relationships, allowing one to ask how species traits influence movements, and whether phylogenetically related species are similar in their movement behavior. We illustrate the modeling framework with two contrasting case studies: a stochastic redistribution model for direct observations of bird movements and a spatially structured diffusion model for capture–recapture data on moth movements. In both cases, the JSMM identified several traits that explain differences in movement behavior among species, such as movement rate increasing with body size in both birds and moths. We show with simulations that the JSMM approach increases precision of species‐specific parameter estimates by borrowing information from other species that are closely related or have similar traits. The JSMM framework is applicable for many kinds of data, and it facilitates a mechanistic understanding of the causes and consequences of interspecific variation in movement behavior.

Refining predictions of population decline at species’ rear edges Vilà Cabrera, Albert; Premoli Il'grande, Andrea Cecilia; Jump, Alistair According to broad‐scale application of biogeographical theory, widespread retractions of species' rear edges should be seen in response to ongoing climate change. This prediction rests on the assumption that rear edge populations are “marginal” since they occur at the limit of the species' ecological tolerance and are expected to decline in performance as climate warming pushes them to extirpation. However, conflicts between observations and predictions are increasingly accumulating and little progress has been made in explaining this disparity. We argue that a revision of the concept of marginality is necessary, together with explicit testing of population decline, which is increasingly possible as data availability improves. Such action should be based on taking the population perspective across a species' rear edge, encompassing the ecological, geographical and genetic dimensions of marginality. Refining our understanding of rear edge populations is essential to advance our ability to monitor, predict and plan for the impacts of environmental change on species range dynamics.

Afrontando el invierno: La rana de ceja corta se reproduce y desarrolla en condiciones climáticas adversas Jara, Fabian Gaston; Cuello, Maria Elena; Úbeda, Carmen A. Los anfibios anuros del bosque andino-patagónico muestran una amplia variedad de adaptaciones a diferentes ambientes acuáticos y a condiciones ambientales regionales. Dentro de estas adaptaciones se destacan particularidades en el ciclo de vida, como por ejemplo que todo o la mayor parte del ciclo transcurra fuera del agua. Este trabajo resume información sobre el ciclo de vida del anuro Batrachyla taeniata, especie conocida como rana de ceja corta, que se reproduce desde mediados del verano hasta mediados del otoño, colocando sus huevos en el suelo húmedo inundable de los bosques donde éstos se incuban. Particularmente, nuestros estudios se llevaron a cabo en el bosque del Parque Municipal Llao Llao, donde la especie habita diferentes ambientes acuáticos. Los renacuajos eclosionan cuando las lluvias otoñales producen el ascenso del nivel de agua o durante la inundación de un humedal, en un estado de desarrollo que les permite alimentarse inmediatamente y continuar su crecimiento en el agua a muy bajas temperaturas durante varios meses antes del arribo de la primavera. A través de observaciones de campo y de la incubación de huevos en condiciones de laboratorio, pudimos determinar la alta dependencia que existe entre las precipitaciones, la temperatura y el desarrollo efectivo de los huevos y su posterior eclosión. Finalmente, señalamos los potenciales efectos del cambio climático a escala regional y cómo este fenómeno podría afectar la supervivencia de esta especie común de los bosques húmedos del Parque Nacional Nahuel Huapi.; Anuran amphibians of the Andean-Patagonian forest show a wide variety of adaptations to different aquatic environments and regional environmental conditions. These adaptations include particularities in their life cycles, such as that all or most of the cycle occur out of water. This work summarizes information about the life cycle of the anuran Batrachyla taeniata, or banded wood frog, which reproduces from midsummer to midautumn, laying eggs out of the water, in the moist soil, where they are incubated. Particularly our studies were carried out in the forest of the Llao Llao Municipal Park, where the species lives in different aquatic environments. Tadpoles hatch when autumn rains cause an increase in water level or during flooding of a wetland, in a state of development that allows them to feed immediately and continue their growth in the water at low temperatures for several months before arrival of spring. Through field observations and incubation of eggs under laboratory conditions we were able to determine the high dependence that exists between precipitation, temperature and the effective development of eggs and their subsequent hatching. Finally, we point out the potential effects of climate change on a regional scale and how this phenomenon could affect the survival of this common species of rainforests of the Nahuel Huapi National Park.

The evolution of the axial skeleton intercentrum system in snakes revealed by new data from the Cretaceous snakes Dinilysia and Najash Garberoglio, Fernando Fabio; Gómez, Raúl Albero; Simões, Tiago R.; Caldwell, Michael Wayne; Apesteguía, Sebastián Snakes are an extremely modifed and long-lived clade of lizards that have either lost or highly altered many of the synapomorphies that would clearly link them to their closest sister-group among squamates. We focus here on one postcranial morphological complex, the intercentrum system which in most non-ophidian squamates is limited to the cervical and caudal regions. The Cervical Intercentrum System (CeIS) is composed of a single intercentral element that sometimes articulates with a ventral projection (hypapophyses) of the centrum; the Caudal Intercentrum System (CaIS) is formed by an intercentral element, the haemal arch/chevron bone, and paired ventral projections of the centrum, the haemapophyses. In modern snakes, the intercentrum element of the CeIS is considered lost or fused to the hypaphophysis, and the chevron bone in CaIS is considered lost. Here, we describe new specimens of the early snake Dinilysia patagonica, and reinterpret previously known specimens of Dinilysia and Najash rionegrina, that do not show the expected snake morphology. The anatomy of these fossil taxa unambiguously shows that free cervical and caudal intercentra attached to distinct downgrowths (hypapophyses and haemapophyses) of the centra, are present in basal fossil snakes, and agrees with the proposed loss of post atlas-axis intercentra in later evolving snakes.

A new specimen with skull and vertebrae of Najash rionegrina (Lepidosauria: Ophidia) from the early Late Cretaceous of Patagonia Garberoglio, Fernando Fabio; Gomez, Raul Orencio; Apesteguía, Sebastián; Caldwell, Michael Wayne; Sánchez, María L.; Veiga, Gonzalo Diego The limbed snake Najash rionegrina from the Cenomanian (early Late Cretaceous) of the La Buitrera Palaeontological Area (LBPA), northern Patagonia is a key taxon in any study of the origin and early evolution of snakes. The original concept of the taxon was based on the holotype and a number of referred specimens including an isolated partial skull; a conservative rebuttal argued this concept was too broad due to the lack of association between the holotype elements and the referred specimens. Here we describe a new snake specimen consisting of a partial skull and closely associated vertebrae from the La Buitrera Locality, one of many productive snake localities within the LBPA. The analysis of the vertebrae of the new specimen identifies distinct features shared with the vertebrae of the N. rionegrina holotype; the partial skull of the new specimen is also identical to the partial skull that formed part of the original concept of N. rionegrina. Phylogenetic analysis, using data from the type and referred specimens, and new materials described here, reconstructs N. rionegrina as a basal snake in a ?madtsoiid? clade outside of crown-group Serpentes. These new morphologies, and autapomorphies recognized in character analyses, permit the construction of a new and expanded diagnosis of N. rionegrina.