A likely magnetic activity cycle for the exoplanet host M dwarf GJ 3512

Current radial velocity data from specialized instruments contain a large amount of information that may pass unnoticed if their analysis is not accurate. The joint use of Bayesian inference tools and frequency analysis has been shown effective to reveal exoplanets but they have been used less frequently to investigate stellar activity. We intend to use radial velocity data of the exoplanet host star GJ 3512 to investigate its magnetic activity. Our study includes the analysis of the photometric data available. The main objectives of our work are to constrain the orbital parameters of the exoplanets in the system, to determine the current level of activity of the star and to derive an activity cycle length for it. An adaptive importance sampling method was used to determine the parameters of the exoplanets orbit. Generalized Lomb-Scargle periodograms were constructed with both radial velocity curve and photometric data. A careful analysis of the harmonic frequencies was conducted in each periodogram. Our fit to multiple Keplerian orbits constrained the orbital parameters of two giant gas planets orbiting the star GJ 3512. The host star showed an increase of its magnetic activity during the last observing campaign. The accurate fit of the radial velocity curve data to the multi-Keplerian orbit permitted to reveal the star rotation in the residuals of the best fit and estimate an activity cycle length of ~ 14 years.Comment: Accepted for publication in the Astronomical Journal. 15 pages, 11 figure

La fauna relacionada a una comunidad prehispánica del Piedemonte Meridional de la provincia de Tucumán (Argentina)

Este trabajo tiene como principal objetivo explorar, desde un enfoque amplio, diversos aspectos (económicos, simbólicos, entre otros) de las relaciones entre los animales y las comunidades prehispánicas del piedemonte meridional de la provincia de Tucumán, tomando como caso de estudio el sitio Yánimas 1 (ca. 1100-800 AP). Para tal fin, se realizó un análisis zooarqueológico de una muestra procedente de un montículo antropogénico de este sitio, utilizando parámetros taxonómicos, anatómicos, tafonómicos y contextuales, además de la consulta de fuentes etnográficas. Los resultados obtenidos permitieron reconocer una gran diversidad de animales aprovechados (entre silvestres y domésticos), que muestran un amplio patrón de distribución biogeográfica. Asimismo, a partir de la evaluación integrada de los datos se sugiere que parte de esta fauna tuvo una activa participación en prácticas rituales y ceremoniales, ya sea como parte de ofrendas, comidas o como objetos con poderes especiales

La fauna relacionada a una comunidad prehispánica del Piedemonte Meridional de la provincia de Tucumán (Argentina)

Este trabajo tiene como principal objetivo explorar, desde un enfoque amplio, diversos aspectos (económicos, simbólicos, entre otros) de las relaciones entre los animales y las comunidades prehispánicas del piedemonte meridional de la provincia de Tucumán, tomando como caso de estudio el sitio Yánimas 1 (ca. 1100-800 AP). Para tal fin, se realizó un análisis zooarqueológico de una muestra procedente de un montículo antropogénico de este sitio, utilizando parámetros taxonómicos, anatómicos, tafonómicos y contextuales, además de la consulta de fuentes etnográficas. Los resultados obtenidos permitieron reconocer una gran diversidad de animales aprovechados (entre silvestres y domésticos), que muestran un amplio patrón de distribución biogeográfica. Asimismo, a partir de la evaluación integrada de los datos se sugiere que parte de esta fauna tuvo una activa participación en prácticas rituales y ceremoniales, ya sea como parte de ofrendas, comidas o como objetos con poderes especiales

Evolutionary ecomorphology of the Falkland Islands wolf Dusicyon australis

The Falkland Islands wolf Dusicyon australis is an extinct canid that was once the only endemic terrestrial mammal to inhabit the Falkland Islands. There is still a puzzling picture of the morphological adaptations of this wolf that quickly evolved from its mainland fossil ancestor: Dusicyon avus. We employ a geometric morphometric approach to identify patterns of skull shape variation in extant canids and Dusicyon spp. The Falkland Islands wolf and its fossil ancestor show a more carnivorous feeding morphology than other South American foxes, and they cluster morphologically with jackals. This supports convergence in skull shape between Dusicyon and Old World canids, although the convergence is not as strong as that exhibited by their sister hyper- and hypocarnivorous taxa

Ellipsometry of iron hydrous oxide layers formed by potentiodynamic techniques

Hydrous iron oxide layers electrochemically formed on iron electrodes in different electrolytes (8.9 < pH < 12.6) have been investigated by ellipsometry. Data have been interpreted on the basis of a duplex oxide layer structure consisting of an inner barrier layer and an outer hydrous layer. The optical response of the hydrous oxide layer depends on the solution composition and in particular on the presence of carbonate ions and the applied potential.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Multiplex Decomposition of Non-Markovian Dynamics and the Hidden Layer Reconstruction Problem

Elements composing complex systems usually interact in several different ways and as such the interaction architecture is well modelled by a multiplex network. However often this architecture is hidden, as one usually only has experimental access to an aggregated projection. A fundamental challenge is thus to determine whether the hidden underlying architecture of complex systems is better modelled as a single interaction layer or results from the aggregation and interplay of multiple layers. Here we show that using local information provided by a random walker navigating the aggregated network one can decide in a robust way if the underlying structure is a multiplex or not and, in the former case, to determine the most probable number of hidden layers. As a byproduct, we show that the mathematical formalism also provides a principled solution for the optimal decomposition and projection of complex, non-Markovian dynamics into a Markov switching combination of diffusive modes. We validate the proposed methodology with numerical simulations of both (i) random walks navigating hidden multiplex networks (thereby reconstructing the true hidden architecture) and (ii) Markovian and non-Markovian continuous stochastic processes (thereby reconstructing an effective multiplex decomposition where each layer accounts for a different diffusive mode). We also state and prove two existence theorems guaranteeing that an exact reconstruction of the dynamics in terms of these hidden jump-Markov models is always possible for arbitrary finite-order Markovian and fully non-Markovian processes. Finally, we showcase the applicability of the method to experimental recordings from (i) the mobility dynamics of human players in an online multiplayer game and (ii) the dynamics of RNA polymerases at the single-molecule level.Comment: 40 pages, 24 figure

La percepción de la calidad del suelo por parte de los productores en una prueba piloto en el área pampeana

p.97-106Para conocer la percepción de la calidad de suelos por parte de productores agropecuarios del área pampeana se aplicó un cuestionario desarrollado en la Universidad de Nebraska (USA). El cuestionario utiliza propiedades consideradas indicadores de calidad y la calificación es de tipo cuali - cuantitativo, respondiendo a pautas establecidas. La muestra fue de tipo casual y se aplicó a productores de pampa ondulada (PO) pampa arenosa (PA) y pampa arenosa semiárida (PAs). Los resultados indican que para ser utilizado en estas zonas se deben introducir algunos ajustes. Las propiedades hídricas, retención de agua, drenaje e infiltración resultan de difícil interpretación y dan origen a respuestas contrapuestas. Los indicadores textura, actividad biológica, dureza y sensación al tacto requieren de una discusión previa con el encuestado y resultaron de difícil evaluación. La calificación final correspondió a 79 por ciento de la calidad en PO, 62 por ciento en PA y 56 por ciento en PAs. La identificación de rasgos positivos y negativos en las percepciones de los productores respecto de la calidad del suelo laboreado permitió recopilar información para el diseño de políticas de gestión. Se considera que la aplicación del cuestionario tiene un doble valor, el de enseñanza, por la inquietud que despertó en los productores y el de reconocimiento del recursos suelo. Se introduce modificaciones a ser aplicadas en futurras evaluaciones como la variabilidad espacial que responde a la morfología del paisaje y que es incluida an la valoración de los encuestados

Alcohol, Brain Derived Neurotrophic Factor and Obesity among People Living with HIV

Introduction In an expanding HAART era, obesity has become a health problem among persons living with HIV (PLWH). Whereas the rising level of obesity has been largely attributed to poor nutrition and exercise habits, differences in biological factors may explain why some individuals gain more weight than others. Thus, our main goal is to prospectively determine in PLWH whether plasma brain-derived neurotrophic factor (BDNF), and hazardous alcohol use (HAU), two overlooked but highly prevalent conditions among PLWH, correlate with an adverse anthropometric profile. Also to test whether these relationships varied in men and women Methods The Platelets mediating Alcohol and HIV Damage Study (PADS) is an ongoing multiethnic study of 400 PLWH receiving regular medical care in South Florida (37% females and 63% males). Semi-annual visits consisted of a medical exam, including anthropometrics to assess both general (body mass index: BMI) and central obesity (waist and hip circumferences). Participants also completed health history questionnaires, and provided a fasting blood sample to obtain BDNF and immune and biochemical assessments. Results A sizable proportion of participants met the National Institutes of Health definition of overweight (BMI = 25?29.9 kg/m2; 26%) and obese (BMI ? 30 kg/m2; 35%). Women were more likely to be obese than men (OR=4.9, 95% CI=2.9?8.2, p=0.0001). Compared to men, women also exhibited the highest mean plasma BDNF levels (9,959 ± 6,578 vs. 7,470 ± 6,068 pg/ml, p=0.0001). Additional analyses indicated that HAU, particularly heavy drinkers, had the smallest waist and hip circumferences if they were males, but the opposite if they were females. High BDNF levels were positively correlated with BMI. Linear regression analysis revealed that gender, BDNF, and HAU were the best predictors of BMI. Conclusion In summary, our findings offer novel insights into the relationships between BDNF, and alcohol use among overweight and obese PLWH. Our results also suggest that these relationships may be inherently different by gender

Self-Assembled Triply Periodic Minimal Surfaces as moulds for Photonic Band Gap Materials

We propose systems with structures defined by self-assembled triply periodic minimal surfaces (STPMS) as candidates for photonic bandgap materials. To support our proposal we have calculated the photonic bands for different STPMS and we have found that, at least, the double diamond and gyroid structures present full photonic bandgaps. Given the great variety of systems which crystalize in these structures, the diversity of possible materials that form them and the range of lattice constants they present, the construction of photonic bandgap materials with gaps in the visible range may be presently within reach.Comment: 3 pages, 2 figures, RevTe