Habitat selection of Molina's hog-nosed skunks in relation to prey abundance in the Pampas grassland of Argentina Castillo, Diego Fabián; Luengos Vidal, Estela Maris; Casanave, Emma Beatriz; Lucherini, Mauro We radiotracked 16 (6 males, 10 females) adult Molina's hog-nosed skunks (Conepatus chinga) to examine habitat selection using compositional analysis at 2 spatial scales in a protected area and a landscape fragmented by agriculture. To aid in understanding the habitat use of skunks, the abundance of invertebrates was estimated in each habitat. Habitat use and selection varied between the 2 study sites. Skunks selected habitat at landscape level but not at home range level in the protected area. In the cropland area skunks showed overall habitat selection at both scales, although at landscape level we did not detect a significant ranking of habitats. In both sites, when we found a significant selection grassland patches ranked first. Although this habitat does not reach 10 of the total area, it presented the highest abundance of Coleoptera. Because Coleoptera are the main prey item of this mephitid, these results support the hypothesis that habitat selection in C. chinga is highly related to food availability. We conclude that the preservation of grassland patches may be essential for managing C. chinga populations in the highly human-modified landscapes of the Pampas.

Petronio, Sat. 117 y Horacio, Serm. II, 7: la parodia de la auctoratio Carmignani, Marcos Flavio En este trabajo nos proponemos analizar la relación intertextual entre el cap. 117 del Satyricon petroniano y Serm. II, 7 de Horacio a partir de la parodia del juramento de la auctoratio que puede verse en Petronio. Para ello, será imprescindible tener en cuenta dos elementos: 1) la complejidad genérica que presenta el Satyricon, con el entrecruzamiento de farsa y sátira en un contexto más general de alusiones a la épica, como ocurre en el episodio de Crotona, y 2) la función que cumple la Sátira. II, 7 en Horacio, con sus portavoces inadecuados del mensaje moral, algo que repercute en el Satyricon.

Microstructural, mechanical and electrochemical characterisation of biomaterial ASTM F745 cast by vacuum Gregorutti, Ricardo Walter; Grau, Jorge Enrique; Elsner, Cecilia Ines Countergravity low pressure casting (CLA) was performed to enhance the properties of ASTMF745 stainless steel (SS), which is usually used as biomaterial. The macro- and microstructureswere compared with those obtained by the conventional process of investment casting (IC). TheSS cast by CLA (SSCLA) exhibited a smaller size of solidification cell and finer dendriticmicrostructure. The average of its dendritic primary spacing was 110·4 mm, while for the same steel cast by IC (SSIC), it was 186·7 μm. The density of non-metallic inclusions δ in the SSCLA was 717 I mm -2, being the majority of them smaller than 1·5 mm. In the case of SSIC, dI was 852 I mm -2, with a size distribution of up to 8 μm. The SSCLA showed a higher breakdown potential than the SSIC, the values being 0·p300 and 0·210 V(saturated calomel electrode) respectively, which means a higher resistance to suffer localised corrosion. Finely, the CLA process also allowed obtaining better mechanical properties.

Actualización de los límites críticos del intervalo hídrico óptimo Pilatti, Miguel Angel; ORELLANA, JORGE ALBERTO de; Imhoff, Silvia del Carmen; Pires Da Silva, Alvaro El Intervalo Hídrico Óptimo (IHO) es la fracción de agua edáfica fácilmente utilizable por los cultivos, durante la cual el suelo puede ser penetrado por las raíces sin mayor resistencia y la aeración no limita la respiración radical. En este trabajo se discuten los límites superior e inferior del IHO. El primero es θCC −agua retenida en capacidad de campo− si garantiza una aceptable capacidad de aire (θa); de lo contrario, el límite se alcanza cuando θa no restringe la respiración radical. El límite inferior queda determinado por la variable de mayor valor entre θRP (contenido hídrico edáfico por debajo del cual las raíces restringen su crecimiento), y θFU (agua fácilmente utilizable por debajo del cual comienza el estrés hídrico). Se analiza y discute la validez de los límites, y las dificultades metodológicas que implican sus determinaciones. Se comparan valores del IHO obtenidos por otros autores, que utilizaron diferentes límites, con los calculados con los límites críticos aquí propuestos. Cada situación agronómica (combinación de suelos, clima, cultivo) requiere valores particulares de IHO que deberán ser determinados para cada región. Para el norte de la Región Pampeana (Argentina) y sus cultivos habituales proponemos los siguientes valores críticos: θCC = contenido hídrico a -10 kPa; θa = 15%; θRP = 2,5 a 6 MPa (según el porcentaje de arcilla) y θFU = -0,17 MPa.

Historia de uso del suelo y contenido de micronutrientes en Argiudoles del centro de la provincia pe Santa Fe (Argentina) Miretti, Maria Celeste; Pilatti, Miguel Angel; Lavado, S.; Imhoff, Silvia del Carmen Las investigaciones realizadas en la zona Central de la provincia de Santa Fe en relación con la concentración y biodisponibilidad de micronutrientes en los suelos son muy limitadas, por lo que los objetivos del presente trabajo fueron: a) determinar si se produjo una disminución en los contenidos de micronutrientes en Argiudoles del centro de la provincia de Santa Fe como consecuencia del uso a que fueron destinados y b) correlacionar la biodisponibilidad con propiedades del suelo que se conoce que fueron afectadas por la intensificación de los sistemas productivos (MO, pH). Se trabajó en el departamento Las Colonias (Santa Fe), en suelos Argiudoles. Se colectaron muestras compuestas de 20 lotes en condiciones prístinas (CP), 22 lotes con uso ganadero dedicados a la producción láctea (G), 24 lotes con historia agrícola-ganadera (AG) y 20 lotes con prolongada historia agrícola (A), que se utilizaron para determinar: pH, carbono orgánico oxidable (CO), boro (B), cobre (Cu), hierro (Fe), manganeso (Mn) y cinc (Zn). Los resultados indican que el pH no varió entre las situaciones estudiadas; los valores de CO disminuyeron (40%) con la intensificación de la agricultura; la concentración de B y Zn se redujo en un 50% de la condición prístina a los lotes con larga historia agrícola; el Cu no sufrió alteraciones; Fe y Mn no muestran una tendencia clara de cambio en función del uso del suelo. En algunos casos podrían ocurrir deficiencias de Zn, por lo que debería controlarse rutinariamente su concentración, especialmente en los sistemas intensivos, para asegurar una disponibilidad adecuada a las necesidades de los cultivos. En todos los sistemas de uso analizados los tenores de micronutrientes presentaron elevada variabilidad.

Defining new criteria for selection of cell-based intestinal models using publicly available databases Christensen, Jon; El-Gebali, Sara; Natoli, Manuela; Sengstag, Thierry; Delorenzi, Mauro; Bentz, Sussane; Bouzourene, Hanifa; Rumbo, Martín; Felsani, Armando; Siissalo, Sanna; Hirvonen, Jouni; Vila, Maya R.; Saletti, Piercarlo; Aguet, Michel; Anderle, Pascale Background: The criteria for choosing relevant cell lines among a vast panel of available intestinal-derived lines exhibiting a wide range of functional properties are still ill-defined. The objective of this study was, therefore, to establish objective criteria for choosing relevant cell lines to assess their appropriateness as tumor models as well as for drug absorption studies.Results: We made use of publicly available expression signatures and cell based functional assays to delineate differences between various intestinal colon carcinoma cell lines and normal intestinal epithelium. We have compared a panel of intestinal cell lines with patient-derived normal and tumor epithelium and classified them according to traits relating to oncogenic pathway activity, epithelial-mesenchymal transition (EMT) and stemness, migratory properties, proliferative activity, transporter expression profiles and chemosensitivity. For example, SW480 represent an EMT-high, migratory phenotype and scored highest in terms of signatures associated to worse overall survival and higher risk of recurrence based on patient derived databases. On the other hand, differentiated HT29 and T84 cells showed gene expression patterns closest to tumor bulk derived cells. Regarding drug absorption, we confirmed that differentiated Caco-2 cells are the model of choice for active uptake studies in the small intestine. Regarding chemosensitivity we were unable to confirm a recently proposed association of chemo-resistance with EMT traits. However, a novel signature was identified through mining of NCI60 GI50 values that allowed to rank the panel of intestinal cell lines according to their drug responsiveness to commonly used chemotherapeutics.Conclusions: This study presents a straightforward strategy to exploit publicly available gene expression data to guide the choice of cell-based models. While this approach does not overcome the major limitations of such models, introducing a rank order of selected features may allow selecting model cell lines that are more adapted and pertinent to the addressed biological question.

Quark matter and meson properties in a Nonlocal SU(3) chiral quark model at finite temperature Gomez Dumm, Daniel Alberto; Contrera, Gustavo Aníbal Gabriel We study the finite temperature behavior of light scalar and pseudoscalar meson properties in the context of a three-flavor nonlocal chiral quark model. The model includes mixing with active strangeness degrees of freedom, and takes care of the effect of gauge interactions by coupling the quarks with a background color field. We analyze the chiral restoration and deconfinement transitions, as well as the temperature dependence of meson masses, mixing angles, and decay constants.

Statistics of major Chilean earthquakes recurrence Silbergleit, Virginia Mabel; Prezzi, Claudia Beatriz In this work, we consider historical earthquakes registered in Chile (from 1900 up to 2010) with epicenters located between 19 and 40°S latitude, in order to evaluate the probabilities of the occurrence of strong earthquakes along Chile in the near future. Applying Gumbel's technique of first asymptotic distribution, Wemelsfelder's theory and Gutenberg-Richter relationship, we estimate that during the next decade strong earthquakes with Richter magnitudes larger than 8. 7-8. 9 could occur along Chile. According to our analysis, probabilities for the occurrence of such a strong earthquake range between 64 and 46% respectively. Particularly in the very well known "seismic gap" of Arica, a convergence motion between Nazca and South American plates of 77-78 mm/year represents more than 10 m of displacement accumulated since the last big interplate subduction earthquake in this area over 134 years ago. Therefore, this area already has the potential for an earthquake of magnitude >8.

A path conditioning method with trap avoidance Gracia, Luis; Sala, Antonio; Garelli, Fabricio This work presents a sliding-mode method for robotic path conditioning. The proposal includes a trap avoidance algorithm in order to escape from trap situations, which are analogous to local minima in potential field-based approaches. The sliding-mode algorithm activates when the desired path is about to violate the robot workspace constraints, modifying it as much as necessary in order to fulfill all the constraints and reaching their limit surface at low speed. The proposed path conditioning algorithm can be used on-line, since it does not require a priori knowledge of the desired path, and improves the conventional conservative potential field-based approach in the sense that it fully exploits the robot workspace. The proposed approach can be easily added as an auxiliary supervisory loop to conventional robotic planning algorithms and its implementation is very easy in a few program lines of a microprocessor. The proposed path conditioning is compared through simulation with the conventional potential field-based approach in order to show the benefits of the method. Moreover, the effectiveness of the proposed trap avoidance algorithm is evaluated by simulation for various trap situations.

El origen y diversificación del crecimiento cambial atípico en plantas fósiles: procesos del desarrollo involucrados; Origin and diversification of atypical cambial growth in fossil plants: developmental processes involved Bodnar, Josefina; Coturel, Eliana Paula En el registro fósil encontramos una serie de morfologías, cuyo origen sólo puede ser inferido a partir de los estudios ontogenéticos actualistas. De este modo, la comprensión de los procesos del desarrollo y el patrón que generan en las plantas es de suma importancia para la Paleobotánica. En este trabajo, se presenta la relación que existe entre los procesos del desarrollo y los diversos patrones observados en el crecimiento secundario de las plantas fósiles. Se estudiaron superficies pulidas, peels y cortes petrográficos de troncos silicificados correspondientes a Lycopsida, Sphenopsida, Medullosales, Corystospermales y Cycadales. Se identificaron una variedad de patrones cambiales, que pueden ser reunidos en dos grupos principales: patrón en espiral y variantes cambiales (e.g. unifacialidad, fragmentación radial y tangencial de elementos vasculares, polixilia, orientación inversa y sistema vascular medular). La aparición del patrón en espiral estuvo relacionada con el origen del clado de las Lygnophyta. Las variantes cambiales caracterizan grupos particulares, y han experimentado una diversificación evolutiva muy importante, vinculada con eventos del desarrollo.; : Origin and diversification of atypical cambial growth in fossil plants: developmental processes involved. We found a series of morphologies in the fossil record whose origin can only be inferred by means of ontogenetic studies. Therefore, comprehension of plant developmental processes and their resultant patterns are extremely important in Paleobotany. In this contribution, we exposed the relation between developmental processes and the different patterns observed in fossil plant secondary growth. Polished surfaces, peels and thin slides of silicified trunks belonging to Lycopsida, Sphenopsida, Medullosales, Corystospermales and Cycadales, were studied. We identified a diversity of cambial patterns which can be clustered in two main groups: whirling pattern and cambial variants (e.g. unifacial, radial and tangential fragmentation of vascular elements, polyxyly, inverse orientation and medullary system). The appearance of whirling pattern was related to the origin of the Lygnophyta clade. The cambial variants characterize specific groups and have undergone a significant evolutionary diversification linked with developmental events.

Diversity, seasonality and structure of bird assemblages associated with three wetlands in the southeastern Pampas, Argentina; Diversidad, estacionalidad y estructura de ensambles de aves asociados a tres humedales del sudeste de la región pampeana, Argentina Josens, Maria Laura; Escalante, Alicia Haydee; Favero, Marco Las lagunas de Los Padres, La Brava y Nahuel Rucá son humedales representativos de la región pampeana. Estos tres ambientes comparten ciertos aspectos limnológicos (tamaño de la cubeta, profundidad media, macrófitas litorales, entre otros), y el uso del suelo aplicado a sus cuencas (por ejemplo, agricultura, ganadería y/o turismo). Durante tres años (mayo del 2006 a mayo del 2009) se estudió la avifauna de estos tres humedales, utilizando para ello censos de transecta y de punto, con el objetivo de caracterizar su abundancia, diversidad, composición de especies y estacionalidad. Se registró un total de 135 especies pertenecientes a 41 familias. El Índice de Importancia Relativa mostró que el cormorán biguá Phalacrocorax olivaceus, la garcilla bueyera Bubulcus ibis, el zampullín pimpollo Podiceps rolland y el morito cariblanco Plegadis chihi fueron las especies más representativas. La riqueza, la composición y abundancia de especies fue diferente entre lagunas. Tales diferencias pueden ser atribuidas a factores particulares como la proximidad a centros urbanos, a otros humedales y a actividades recreativas. Considerando que la región pampeana está actualmente bajo un fuerte impacto antrópico, el presente estudio contribuye a la mejora y actualización de los planes de manejo de estas áreas.; Los Padres, La Brava and Nahuel Rucá lakes are typical wetlands of the Pampean region. These three shallow lakes share certain limnological features (size, mean depth, littoral macrophytes, among others) and the land usage in their basins (e.g. agriculture, cattle ranching and/or touristic activities). We surveyed the bird community at these three wetlands over three years (May 2006-May 2009), using transects and point counts to characterise their species richness, abundance, community composition and seasonality.We recorded a total of 135 species belonging to 41 families. The Relative Importance Index showed that the neotropic cormorant Phalacrocorax olivaceus, the cattle egret Bubulcus ibis, the white-tufted grebe Rollandia rolland and the white-faced ibis Plegadis chihi are the most representative species. Species richness, species composition and abundance differed between wetlands. Such differences could be attributed to particular factors such as proximity to urban centres or other wetlands, and to the impact of recreational activities. Considering that the Pampean region is currently under strong anthropogenic impacts, the present study contributes to the improvement of management plans that are currently in place or under development.

Cuticular hydrocarbon pattern as a chemotaxonomy marker to assess intraspecific variability in Triatoma infestans, a major vector of Chagas' disease Calderón Fernández, Gustavo Mario; Girotti, Juan Roberto; Juarez, Marta Patricia Triatoma infestans Klug (Hemiptera: Reduviidae) populations were sampled in various localities throughout most of the species' geographic range of distribution in Argentina, Bolivia, Paraguay and Peru. In order to contribute to understanding of the diversity and population structure of this major vector of Chagas' disease, cuticular hydrocarbon (CHC) profiles were analysed by capillary gas chromatography and variations evaluated by statistical methods of classification and ordination. High levels of intrapopulation variation were detected, along with low levels of variability among populations. Based on relative amounts of the major odd-numbered straight-chain hydrocarbons n-C27 to n-C33, two hydrocarbon phenotypes were evident, unequally distributed along the species' geographic range. Analysis of CHC patterns showed that T. infestans populations segregate into two major groups consisting of an Andean group, which comprises specimens from Peru and most parts of Bolivia, and a non-Andean group, which includes all specimens from Argentina and Paraguay, together with those from Tarija (Bolivia). Pyrethroid-resistant and -susceptible specimens were differentiated based on relative amounts of some straight and monomethyl-branched hydrocarbon components.

A model driven development approach based on a reference model for predicting disruptive events in a supply process Fernández, Érica Soledad; Salomone, Hector Enrique; Chiotti, Omar Juan Alfredo Due to the impossibility of predicting with certainty the occurrence of disruptive events, buffers defined to obtain a robust schedule could not absorb all the changes. Then, local modifications of the schedule are usually performed to avoid a new planning task. For this task, obtaining disruptive event information in advance can help to make better decisions. As a result, ability to predict disruptive events that affect the execution of the supply process an order represents is required. With the objective of satisfying this requirement, this work proposes a model driven development approach based on a reference model to automate the generation of the monitoring model of a supply process able to anticipate the occurrence of a disruptive event by monitoring variables that can explain it. The approach proposes both a reference model to represent the monitoring model independently of the implementation platform, and a specific model to represent the monitoring model with the particular language of the implementation platform. An engine based on transformation rules allows automating the generation of a platform dependent monitoring model from an instance of a platform independent metamodel. The monitoring component of a SCEM system has been developed, which implements the transformation engine as a Bayesian Network model, and uses an appropriate tool to execute it. For an empirical validation of the model three case studies are presented.

Génesis de las acumulaciones de carbonatos en aridisoles nordpatagónicos: su significado paleopedológico; Genesis of carbonate accumulations in North Patagonic aridisols: its paleopedological significance Bouza, Pablo Jose El objetivo de este trabajo es dar a conocer la génesis de las acumulaciones de carbonatos ampliamente distribuidas en los suelos del NE del Chubut a través del análisis de las propiedades físicas, químicas y mineralógicas, como así también dilucidar, en combinación con estas propiedades edáficas, si dichas acumulaciones pueden ser utilizadas como indicadores paleopedológicos mediante el análisis de las composiciones isotópicas de δ13C y δ18O. Los suelos estudiados se asocian a cordones litorales depositados durante el MIS 5e (Formación Caleta Valdés) y a antiguas terrazas glaciofluviales y pluviofluviales de edad Plio-Pleistoceno (Rodados Patagónicos). Los contenidos de carbonatos aumentan en función de la edad de las superficies geomorfológicas (terrazas), constituyendo una herramienta para correlacionar suelos y paleosuelos (cronosecuencia). La presencia de rasgos morfológicos típicos (estructura laminar, nódulos calcíticos,pendants,fábrica de tipo alfa,pellets y ooides) y de palygorskita y sepiolita formadas durante los procesos de calcretización, indican que las acumulaciones de carbonatos son de origen pedogenético. El análisis de las composiciones isotópicas de δ13C y δ18O mostraron una aceptable correlación positiva (r2= 0,5; p<0,001) indicando una correspondencia entre ensambles de plantas con mayor proporción de C4, tolerantes al estrés hídrico, con altas temperatura (valores más positivos de δ13C y de δ18O respectivamente. Las calcretas presentes en la Formación Caleta Valdés se habrían formado durante la culminación del período MIS 5 (5a-c), mientras que las alojadas en los Rodados Patagónicos se habrían desarrollado durante algún interglacial más cálido y seco, presumiblemente durante el MIS 11.; The aim of this paper is to report on the origin of the carbonate accumulations in soils of the northeast of the Chubut province, through analysis of physical, chemical and mineralogical properties as well as to elucidate, in combination with these soil properties, if such accumulations can be used as paleopedological indicators by analyzing the isotopic compositions of d18O and d13C. The studied soils are associated with littoral terraces formed during the MIS 5e (Caleta Valdés Formation) and with glaciofuvial and pluviofuvial terraces of Plio-Pleistocene age (Rodados Patagónicos). The carbonate content increases with the age of the geomorphic surfaces (terraces), constituting a tool to correlate soils and paleosols (chronosequence). The accumulations of pedogenetic carbonates are revealed by the presence of typical morphological features (laminar structure, calcitic nodules, pendants, alpha-type fabric, pellets and ooids) and palygorskite and sepiolite formed during calcretización processes. The analysis of the isotopic compositions of d13C and d18O showed an acceptable positive correlation (r2 = 0.5, p <0.001) indicating a correspondence between assemblages of plants with higher proportion of C4, which are tolerant to water stress and high temperatures (values more positive of d13C and d18O respectively). The calcretes present in Caleta Valdés Formation were formed during the culmination of MIS 5 period (5a-c), while the carbonates present in the Rodados Patagónicos would have developed in a warmer and drier interglacial period, presumably during MIS 11.

A new species of Oxelytrum Gistel (Coleoptera, Silphidae) from southern Argentina, with a key to the species of the genus Oliva, Adriana A new species of the forensically interesting genus Oxelytrum Gistel (Coleoptera, Silphidae), O. selknan, is described from Santa Cruz and Tierra del Fuego provinces, Argentina. The new species resembles O. biguttatum (Philippi) in outer aspect, but has different male genitalia, in particular a median lobe longer than the paramera. All the described species of Oxelytrum have the median lobe shorter than the paramera. The internal sac, as far as it could be reconstructed from dry-pinned specimens, also shows differences between the two species. A key to the species of Oxelytrum is given and illustrated.

Photophysics of polyaniline: Sequence-length distribution dependence of photoluminescence quenching as studied by fluorescence measurements and Monte Carlo simulations Antonel, Paula Soledad; Volker, Edgar; Molina, Fernando Víctor The dependence of the fluorescence quenching of electropolymerized poly(aniline-co-m-chloroaniline) with polymer composition has been investigated. Fluorescence emission in polyaniline is quenched when the polymer is oxidized (brought to emeraldine state); the copolymers exhibit decreasing quenching as chloroaniline contents increases. Quenching shows a strong decrease in the presence of 0.1% m-chloroaniline monomers in the feed. The presence of dichloroaniline units in the copolymer was confirmed by XPS measurements and a terpolymerization reaction scheme was developed, obtaining the kinetic parameters. By Monte Carlo simulation the sequence length distributions for different compositions were obtained and compared; it was found that quenching, for low aniline contents, requires aniline sequences of at least three units. The strong decrease in quenching at low m-chloroaniline contents is attributed to a double effect: breaking of conjugation in the emeraldine form by the presence of the chlorinated unit, and a disruption of the close chain packing in the crystalline domains, preventing state delocalization and thus efficient quenching. © 2012 Elsevier Ltd. All rights reserved.

Estudios Paleoetnobotánicos del Sitio 1, Localidad Arqueológica Lobería I, Buenos Aires, Argentina: Aproximación al manejo de recursos vegetales; Paleoethnobotanical studies of loberia i archeological area, Site 1, Buenos Aires, Argentina: An assessment of plant resource use Colobig, María de Los Milagros El sitio 1 de la localidad arqueológica Lobería I se ubica en el sector oriental de las Sierras de Tandilia. Es un reparo rocoso con registro de ocupaciones humanas desde el Holoceno temprano hasta el tardío. En este último período se destaca la utilización intensiva de la cueva en el rango de 700 a 900 años AP. En este artículo se presentan los resultados del análisis de microfósiles silíceos, principalmente de origen vegetal, provenientes de muestras sedimentarias de perfiles del interior del sitio (P1 y P2) y exteriores a él (P3 y P4). Los objetivos principales son establecer pautas de gestión de recursos vegetales y estimar las condiciones paleoambientales a lo largo de esa secuencia cronoestratigráfica. Se observan variaciones entre los microfósiles obtenidos de los perfiles del sitio y los perfiles exteriores. Esto permite sostener, junto con otras líneas de evidencia, que hubo incorporación de vegetales a la cueva, lo que indicaría posibles relaciones de intercambio, movilidad, etc., y aspectos paleoambientales ocurridos a escala microambiental y regional.; Lobería I archaeological area, site 1, is located in the eastern Tandilia Range. The site is located on rocky spur with an occupational history extending from the Early through to Late Holocene. It is during the latter period that there is an intensive occupation of the cave between 700 to 900 years BP. This paper presents the results of siliceous microfossil analysis, mainly of plant origin, taken from sedimentary samples inside (P1 and P2) and outside (P3 and P4) the site. The main aim was to establish guidelines concerning plant resource management as well as evaluating the paleo-environmental conditions in existence during the chrono-stratigraphic sequence of the site. Variability was observed between the microfossils obtained from the inside and outside of the site. This suggests, in conjunction with other lines of evidence, that these microfossils where brought into the cave, this in turn possibly indicates relations of exchange, mobility, etc., including signaling of paleo-environmental events that occurred at a micro-environmental and regional scale.

Direct reductive amination of aldehydes using lithium-arene(cat.) as reducing system. A simple one-pot procedure for the synthesis of secondary amines Nador, Fabiana Gabriela; Moglie, Yanina Fernanda; Ciolino, Andrés Eduardo; Pierini, Adriana Beatriz; Dorn, Viviana; Yus, Miguel; Alonso, Francisco; Radivoy, Gabriel Eduardo A simple one-pot procedure for the direct reductive amination of aldehydes using lithium powder and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB) or a polymer supported naphthalene as reducing system is described. The direct reductive amination of a variety of aldehydes with primary amines was achieved simply by adding a mixture of the corresponding carbonyl compound and the amine, over a solution of the lithium arenide in THF at room temperature. For most of the substrates tested the main reaction products were the secondary amines along with variable amounts of the corresponding alcohol and/or imine products. Theoretical DFT calculations have been applied in order to explain the differences in reactivity observed for aromatic substrates. © 2012 Elsevier Ltd. All rights reserved.

Mercury levels in feathers of Magellanic penguins Frias, Jorgelina E.; Gil, Monica Noemi; Esteves, Jose Luis; Garcia Borboroglu, Jorge Pablo; Kane, Olivia J.; Smith, Jeff R.; Boersma, P. Dee Feathers are useful to determine mercury (Hg) contamination. We evaluated the mercury concentration in feathers of Magellanic penguins (Spheniscus magellanicus) age 1.5. years to 25. years at Punta Tombo, Argentina before and during their molt. Mercury ranged between <1.4 and 367. ng/g. dry. weight, with three extreme high values (8996. ng/g, 3011. ng/g and 1340. ng/g) all in young adults. The median concentration was lowest for juveniles and significantly higher for adults but with high variation among older adults. Males and females had similar mercury loads. Compared with other penguin species, concentrations in Magellanic penguins were low. Mercury levels for Magellanic penguins in the Southwest Atlantic for older adults averaged 206 ± 98 ng/g, and serve as a baseline for biomonitoring and/or ecotoxicological studies.

Heavy metal availability in pelargonium hortorum rhizosphere: Interactions, uptake and plant accumulation Orroño, Daniela I.; Schindler, Valeria; Lavado, Raul Silvio The rhizosphere is a key area for the plant metal uptake. We studied heavy metal availability in the rhizosphere and the bulk soil, the interactions between metal ions, and their effects on heavy metal uptake and accumulation by Pelargonium hortorums (geranium). A pot experiment with plants of geranium was conducted in a soil spiked with cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn) singly or in combinations. Bulk soils showed higher concentrations of extractable metals than rhizosphere soils, and metals accumulated preferentially in roots relative to aerial biomass. Regression analysis showed that soil extractable Cr, Ni and Pb were related (R2 = 0.90) to their concentration in plants, but there was no correlation between soil and plants for Cd, Cu, and Zn. Larger concentrations of metals were found when they were added in combinations rather than individually, and availability and uptake were directly related to the level of metals applied.