Habitat modification effects on anuran food webs in the Colombian tropical dry forest

Habitat loss and transformation are major threats to biodiversity and ecosystem functioning, but their effects on species interaction are often poorly understood. We evaluated effects of habitat transformation and seasonality on anuran-prey food webs in Colombian dry-forests. We asked whether anthropic transformation (anthropic vs natural) and/or seasonality (dry, minor and major rain seasons) affect predator load on arthropods, the occurrence of energetic bottlenecks, and the diet overlap of anurans. We selected six dry forest sites in the Caribbean of Colombia, sampled anurans, and identified their stomach contents to construct anuran-prey food webs. We show that the global structure of food webs was affected by disturbance and seasonality, but not by their interaction. Prey vulnerability was higher in anthropic habitats. Habitat transformation enhanced diet overlap among predators, but there was not a differential effect of habitat type according to seasonality for network metrics. Our study shows a strong effect of natural vegetation modification in tropical dry forest on anuran-prey food webs, while seasonality did not seem to further mediate these effects

Resistance of stud shear connectors in composite beams using profiled steel sheeting

In composite beam design, headed stud shear connectors are commonly used to transfer longitudinal shear forces across the steel-concrete interface. This paper describes the structural performance of shear connection in composite beams with profiled steel sheeting. An accurate and efficient nonlinear Finite Element (FE) model was developed to study the behavior of headed stud shear connectors welded through the deck. The concrete slab considered in this article uses profiled steel sheeting with ribs perpendicular to the longitudinal axis of the steel beam. The material nonlinearities were included in the FE model. The concrete was modeled considering a damaged plasticity model available in ABAQUS software. The results obtained from FE analysis were verified against experimental results. A parametric study was conducted to observe the effects of changing of both the stud position inside the rib of profiled steel sheeting and the concrete strength on the resistance of the stud shear connector. The shear resistance of stud connectors obtained from the FE analysis and many experimental push-out tests whose results are available in the literature were used as a database to compare with design shear resistance calculated using AISC-LRFD and Eurocode 4. It is found that the shear resistance of stud connectors, obtained from the design rules specified in these codes, in some cases is greatly underestimated, and in other cases significantly overestimated.Peer ReviewedPostprint (author's final draft

Numerical modelling with experimental validation applied to the study of stud connectors behaviour in concrete and steel composite structures

In this work, the behaviour of stud shear connectors in composite structures is studied, starting from the via numeric simulation of the push out test in a steel beam – with solid concrete slab concrete section is studied. The study considers material non-linearity material of concrete and steel, adopting firstly a bilinear model for both (steel and concrete), and in the second case, to the difference ofdiffering from other authors, the concrete damage plasticity of the concrete. ABAQUS is used to model the push out test. The basis and methodology of the modelmodelling process push out test are explained. The numerical results obtained are in accordance with the experimental results, which . This aspect shows the efficacythat of the finite element method is efficient for the in studying the behaviour of stud shear connector’s behavior. Finally, the capacities of shear connections obtained from the finite element analysis were are compared with to the connection strengths calculated using the American Specification (AISC-LRFD (2005)), European Code (Eurocode 4 (2004)) and Cuban Code (NR-080-2004). It this was is observed that, these specifications over estimate this value (capacities of shear connections) in many cases.Postprint (published version

Local diversity of native arbuscular mycorrhizal symbionts differentially affects growth and nutrition of three crop plant species

Intact whole native AMF communities occurring across a 100-m-long field were used for the evaluation of plant performance, as determined by the actual fungal species colonizing host roots. The soil from distinct plots within a "hot spot" field was collected to set up 54 experimental units where three different plant species were grown, in order to test whether the whole native AMF communities were able to differentially affect plant growth, to assess the genetic identity of the AMF actually colonizing the tested plants and to analyse their community composition in the different hosts. Molecular analyses revealed that plant growth and nutrition of the crop plants were differentially affected by the diverse native arbuscular mycorrhizal communities colonizing the roots of the three plants, whose performance varied depending on the identity of plant hosts and fungal symbionts, more than on a rich and diversified AMF community. Such results, improving our understanding of AMF distribution at the local scale, represent a starting point allowing the selection, isolation and characterization of the most efficient AMF assemblages to be used as inoculants in sustainable food production systems

Suitability of Magnetic Microbolometers based on Paramagnetic Temperature Sensors for CMB Polarization Measurements

High resolution maps of polarization anisotropies of the Cosmic Microwave Background (CMB) are in high demand, since the discovery of primordial B-Modes in the polarization patterns would confirm the inflationary phase of the Universe that would have taken place before the last scattering of the CMB at the recombination epoch. Transition Edge Sensors (TES) and Microwave Kinetic Inductance Detectors (MKID) are the predominant detector technologies of cryogenic detector array based CMB instruments that search for primordial B-Modes. In this paper we propose another type of cryogenic detector to be used for CMB survey: A magnetic microbolometer (MMB) that is based on a paramagnetic temperature sensor. It is an adaption of state-of-the-art metallic magnetic calorimeters (MMCs) that are meanwhile a key technology for high resolution $\alpha$, $\beta$, $\gamma$ and X-ray spectroscopy as well as the study of neutrino mass. The effort to adapt MMCs for CMB surveys is triggered by their lack of Johnson noise associated with the detector readout, the possibility of straightforward calibration and higher dynamic range given it possesses a broad and smooth responsivity dependence with temperature and the absence of Joule dissipation which simplifies the thermal design. A brief proof of concept case study is analyzed, taking into account typical constraints in CMB measurements and reliable microfabrication processes. The results show that MMBs provide a promising technology for CMB polarization survey as their sensitivity can be tuned for background limited detection of the sky while simultaneously maintaining a low time response to avoid distortion of the point-source response of the telescope. As the sensor technology and its fabrication techniques are compatible with TES based bolometric detector arrays, a change of detector technology would even come with very low cost.Comment: 20 pages, 11 figures. Published in SPIE's Journal of Astronomical Telescopes, Instruments and Systems (JATIS

La modernización del campo y la globalización económica

El presente libro incluye las ponencias presentadas en el del XIV Seminario de Economía Agrícola del Tercer Mundo, en el cual participan distinguidos especialistas nacionales y extranjeros, atentos a la dinámica y a la problemática actual de la producción primaria y el desarrollo rural de México y el mundo. El interés se centró en la elaboración de análisis críticos y propositivos en torno a los cambios ocurridos durante los últimos años en el sector rural mexicano a la luz del proceso de modernización y globalización económica en que está inmerso nuestro país. Los trabajos presentados en el Seminario muestran un consenso básico en torno a la importancia estratégica del sector agropecuario y rural para la construcción de un proyecto de desarrollo nacional sostenido, equilibrado y democrático

Silencios que gritan en la escuela: Dispositivos, espacio urbano y desigualdades

En todos los maravillosos mundos que descubre la escritura, advierte Ong (1987), todavía le es inherente y en ellos vive la palabra hablada. Todos los textos escritos están de algún modo relacionados con el mundo del sonido, el ambiente natural del lenguaje, para transmitir sus significados. “Leer” un texto, dice, quiere decir convertirlo en sonidos, en voz alta o en la imaginación… Así, la escritura no puede nunca prescindir de la oralidad. Este libro es eso en buena medida, una escritura hablada, compuesto de distintas voces, sonidos a veces tenues, a veces graves o vibrantes, otras que tienden al silencio. Habla de, con y entre otros. En ese gesto se convierte en un diálogo entre muchos. Un hablar de y con que nos envuelve en la experiencia de escritura compartida. Textos que expresan nuestros encuentros en la universidad, en las escuelas, en el barrio. Voces de investigadorxs junto con estudiantes y docentes, diversas palabras, miradas, sensaciones y silencios. Y entre estos instantes de encuentros y desencuentros la posibilidad de pensar/nos...Fil: Langer, Eduardo Daniel. Universidad Nacional de San Martin. Escuela de Humanidades. Laboratorio de Investigacion En Ciencias Humanas. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Laboratorio de Investigacion En Ciencias Humanas.; Argentina. Universidad Nacional de la Patagonia Austral; ArgentinaFil: Armella, Julieta. Universidad Nacional de San Martin. Escuela de Humanidades. Laboratorio de Investigacion En Ciencias Humanas. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Laboratorio de Investigacion En Ciencias Humanas.; ArgentinaFil: Orlando, Gabriela Beatriz. Universidad Nacional de San Martin. Escuela de Humanidades. Laboratorio de Investigacion En Ciencias Humanas. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Laboratorio de Investigacion En Ciencias Humanas.; Argentina. Universidad Nacional de San Martín. Escuela de Humanidades. Centro de Estudios Desigualdades, Sujetos e Instituciones; ArgentinaFil: Schwamberger, Cintia María. Universidad Nacional de San Martin. Escuela de Humanidades. Laboratorio de Investigacion En Ciencias Humanas. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Laboratorio de Investigacion En Ciencias Humanas.; Argentina. Universidad Nacional de San Martín. Escuela de Humanidades. Centro de Estudios Desigualdades, Sujetos e Instituciones; Argentina. Consejo Latinoamericano de Ciencias Sociales; ArgentinaFil: Dafunchio, Sofia. Universidad Nacional de San Martin. Escuela de Humanidades. Laboratorio de Investigacion En Ciencias Humanas. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Laboratorio de Investigacion En Ciencias Humanas.; Argentina. Universidad Nacional de San Martín. Escuela de Humanidades. Centro de Estudios Desigualdades, Sujetos e Instituciones; ArgentinaFil: Bonilla, Marco Antonio. Universidad Nacional de San Martin. Escuela de Humanidades. Laboratorio de Investigacion En Ciencias Humanas. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Laboratorio de Investigacion En Ciencias Humanas.; ArgentinaFil: Carpentieri, Yanina Andrea. Universidad Nacional de San Martin. Escuela de Humanidades. Laboratorio de Investigacion En Ciencias Humanas. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Laboratorio de Investigacion En Ciencias Humanas.; ArgentinaFil: Mantiñán, Luciano Martín. Universidad Nacional de San Martín. Escuela de Humanidades. Laboratorio de Investigación en Ciencias Humanas - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Laboratorio de Investigación en Ciencias Humanas; ArgentinaFil: Bussi, Eliana Mercedes. Universidad Nacional de San Martín. Escuela de Humanidades. Laboratorio de Investigación en Ciencias Humanas - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Laboratorio de Investigación en Ciencias Humanas; Argentina. Universidad de Málaga; EspañaFil: Peuchot, Patricia. Universidad Nacional de San Martin. Escuela de Humanidades. Laboratorio de Investigacion En Ciencias Humanas. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Laboratorio de Investigacion En Ciencias Humanas.; Argentina. Universidad Nacional de San Martín. Escuela de Humanidades. Centro de Estudios Desigualdades, Sujetos e Instituciones; ArgentinaFil: Rodríguez, Germán. Universidad Nacional de San Martín. Escuela de Humanidades. Centro de Estudios Desigualdades, Sujetos e Instituciones; ArgentinaFil: Machado, Mercedes Libertad. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Autonoma de Entre Rios. Facultad de Humanidades Artes y Ciencias Sociales. Centro Interdisciplinario de Investigacionesen El Campo de Las Humanidades, Arte y Educacion.; Argentina. Universidad Nacional de San Martín. Escuela de Humanidades. Centro de Estudios Desigualdades, Sujetos e Instituciones; ArgentinaFil: Ojeda, Manuel. Universidad Nacional de San Martín. Escuela de Humanidades. Centro de Estudios Desigualdades, Sujetos e Instituciones; Argentina. Instituto Nacional de Educación Física; Argentina. Colegio Dr. Juan Segundo Fernández; ArgentinaFil: Muñoz Cabrera, Alejandro. Escuela de Educación Secundaria 8 Esteban Echeverría; Argentina. Universidad del Este; ArgentinaFil: Abalsamo, Miriam. No especifíca

Metabolite and lipoprotein profiles reveal sex-related oxidative stress imbalance in de novo drug-naive Parkinson's disease patients

Parkinson's disease (PD) is the neurological disorder showing the greatest rise in prevalence from 1990 to 2016. Despite clinical definition criteria and a tremendous effort to develop objective biomarkers, precise diagnosis of PD is still unavailable at early stage. In recent years, an increasing number of studies have used omic methods to unveil the molecular basis of PD, providing a detailed characterization of potentially pathological alterations in various biological specimens. Metabolomics could provide useful insights to deepen our knowledge of PD aetiopathogenesis, to identify signatures that distinguish groups of patients and uncover responsive biomarkers of PD that may be significant in early detection and in tracking the disease progression and drug treatment efficacy. The present work is the first large metabolomic study based on nuclear magnetic resonance (NMR) with an independent validation cohort aiming at the serum characterization of de novo drug-naive PD patients. Here, NMR is applied to sera from large training and independent validation cohorts of German subjects. Multivariate and univariate approaches are used to infer metabolic differences that characterize the metabolite and the lipoprotein profiles of newly diagnosed de novo drug-naive PD patients also in relation to the biological sex of the subjects in the study, evidencing a more pronounced fingerprint of the pathology in male patients. The presence of a validation cohort allowed us to confirm altered levels of acetone and cholesterol in male PD patients. By comparing the metabolites and lipoproteins levels among de novo drug-naive PD patients, age- and sex-matched healthy controls, and a group of advanced PD patients, we detected several descriptors of stronger oxidative stress