Breve enunciación de los estudios hidrológicos, especialmente en lo referente a hidrogeología, en la provincia de Buenos Aires (Argentina)

En esta comunicación se hace una sucinta referencia a los estudios hidrogeológicos principales más recientes, y a los que se encuentran en ejecución dentro del ámbito de la Provincia de Buenos Aires (Argentina). Se intenta subdividir su territorio en regiones hidrogeológicas con características climáticas, geomorfológicas e hidrológicas más o menos semejantes.In his short paper, a brief reference is made to the more receno, principal hydrogeologic studies in development inside the Buenos Aires Province (Argentina). There is likewise an attempt on subdividing the area in hydrologic regions, under more or less similar climatic, geomorphologic and hydrologic characteristic

Advanced Exergy Analysis in the Dynamic Framework for Assessing Building Thermal Systems

This work applies the Dynamic Advanced Exergy Analysis (DAEA) to a heating and domestic hot water (DHW) facility supplied by a Stirling engine and a condensing boiler. For the first time, an advanced exergy analysis using dynamic conditions is applied to a building energy system. DAEA provides insights on the components’ exergy destruction (ED) by distinguishing the inefficiencies that can be prevented by improving the quality (avoidable ED) and the ones constrained because of technical limitations (unavoidable ED). ED is related to the inherent inefficiencies of the considered element (endogenous ED) and those coming from the interconnections (exogenous ED). That information cannot be obtained by any other approach. A dynamic calculation within the experimental facility has been performed after a component characterization driven by a new grey-box modelling technique, through TRNSYS and MATLAB. Novel solutions and terms of ED are assessed for the rational implementation of the DAEA in building energy installations. The influence of each component and their interconnections are valuated in terms of exergy destruction for further diagnosis and optimization purposes.BMWi, 03ET1218B, Anwendung exergiebasierter Methoden zur Verbesserung von Gebäudeenergiesysteme

Investigación hidrológica de la Cuenca del Arroyo Azul, provincia de Buenos Aires

El presente trabajo que se pudo llevar adelante mediante un subsidio de la CIC y el apoyo logístico de la Municipalidad de Azul, se originó a partir de los problemas provocados por las inundaciones en la ciudad de Azul en Abril de 1980. Por no ser las inundaciones un problema aislado dentro del ciclo hidrológico, por la importancia vital del recurso hídrico y por los efectos secundarios que pueden tener las obras, se abarca una temática más amplia que la sintética, que errónea y desprevenidamente puede suponerse como suficiente. El primer capítulo es introductorio e incluye la metodología desarrollada y las técnicas empleadas, adaptadas a las condiciones naturales y antrópicas de la región así como a la realidad de los datos antecedentes y a los logrados en las observaciones de campo en el corto tiempo disponible. En el segundo capítulo, en base a la sistematización, valoración, análisis e interpretación de la información, se efectúa una amplia caracterización hidrológica en la Cuenca del Arroyo Azul y sus aledaños, pero con las limitaciones lógicas a estos estudios, que deben ser permanentes y efectuarse en e- tapas de sucesivas aproximaciones. Por último, el tercer capítulo, fundamentado en los anteriores, abarca aspectos aplicados y se delinean en él soluciones tentativas a través del manejo del recurso hídrico, que consiste en: I) Obras de retardo y regulación de crecidas. II) Operaciones de limpieza y mantenimiento del cauce. III) Delineamiento de un sistema de pronóstico preventivo a bajo costo y relativa fácil operatividad. Como no puede ser de otra forma, tratándose problemas de los recursos hídricos, se establecen además bases generales para prevenir y regular los problemas a mediato y largo plazo. Las pautas se resumen en la complementación de una política de manejo basado en el uso conjuntivo intensivo, lo cual se sustenta en: I) Estudios de control y aproximaciones sucesivas. II) Complementación de redes de mediciones hidrométricas.Digitalizado en SEDICI-CIC Digita

The supersoft X-ray source in V5116 Sgr I. The high resolution spectra

Classical novae occur on the surface of an accreting white dwarf in a binary system. After ejection of a fraction of the envelope and when the expanding shell becomes optically thin to X-rays, a bright source of supersoft X-rays arises, powered by residual H burning on the surface of the white dwarf. While the general picture of the nova event is well established, the details and balance of accretion and ejection processes in classical novae are still full of unknowns. The long-term balance of accreted matter is of special interest for massive accreting white dwarfs, which may be promising supernova Ia progenitor candidates. V5116 Sgr was observed as a bright and variable supersoft X-ray source by XMM-Newton 610~days after outburst. The light curve showed a periodicity consistent with the orbital period. During one third of the orbit the luminosity was a factor of seven brighter than during the other two thirds of the orbital period. In the present work we aim to disentangle the X-ray spectral components of V5116 Sgr and their variability. We present the high resolution spectra obtained with XMM-Newton RGS and Chandra LETGS/HRC-S in March and August 2007. The grating spectrum during the periods of high-flux shows a typical hot white dwarf atmosphere dominated by absorption lines of N VI and N VII. During the low-flux periods, the spectrum is dominated by an atmosphere with the same temperature as during the high-flux period, but with several emission features superimposed. Some of the emission lines are well modeled with an optically thin plasma in collisional equilibrium, rich in C and N, which also explains some excess in the spectra of the high-flux period. No velocity shifts are observed in the absorption lines, with an upper limit set by the spectral resolution of 500 km/s, consistent with the expectation of a non-expanding atmosphere so late in the evolution of the post-nova.Comment: 12 pages, 15 figures, 4 tables; accepted for publication in Astronomy and Astrophysic

Asymptotic Expansions of Jacobi Polynomials for Large Values of Beta

Asymptotic approximations of Jacobi polynomials are given for large values of the Beta-parameter and of their zeros. The expansions are given in terms of Laguerre polynomials and of their zeros. The levels of accuracy of the approximations are verified by numerical examples.This work was supported by Ministerio de Econom a y Competitividad, project MTM2015-67142-P (MINECO/FEDER, UE). NMT thanks CWI, Amsterdam, for scienti c support

N-benzylpiperidine derivatives as α7 nicotinic receptor antagonists

This document is the accepted manuscript version of a Published Work that appeared in final form in ACS Chemical Neuroscience 7.8, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see DOI: 10.1021/acschemneuro.6b00122.A series of multitarget directed propargylamines, as well as other differently susbstituted piperidines have been screened as potential modulators of neuronal nicotinic acetylcholine receptors (nAChRs). Most of them showed antagonist actions on α7 nAChRs. Especially, compounds 13, 26, and 38 displayed submicromolar IC50 values on homomeric α7 nAChRs, whereas they were less effective on heteromeric α3β4 and α4β2 nAChRs (up to 20-fold higher IC50 values in the case of 13). Antagonism was concentration dependent and noncompetitive, suggesting that these compounds behave as negative allosteric modulators of nAChRs. Upon the study of a series of less complex derivatives, the N-benzylpiperidine motif, common to these compounds, was found to be the main pharmacophoric group. Thus, 2-(1-benzylpiperidin-4-yl)-ethylamine (48) showed an inhibitory potency comparable to the one of the previous compounds and also a clear preference for α7 nAChRs. In a neuroblastoma cell line, representative compounds 13 and 48 also inhibited, in a concentration-dependent manner, cytosolic Ca2+ signals mediated by nAChRs. Finally, compounds 38 and 13 inhibited 5-HT3A serotonin receptors whereas they had no effect on α1 glycine receptors. Given the multifactorial nature of many pathologies in which nAChRs are involved, these piperidine antagonists could have a therapeutic potential in cases where cholinergic activity has to be negatively modulated.This work was supported by grants SAF2011-22802 to S.S., SAF2012-33304 to J.M.-C., CSD2008-00005 (the Spanish Ion Channel Initiative-CONSOLIDER INGENIO 2010) to M.C. from the Spanish Ministry of Science and Innovation (Ministerio de Economía y Competitividad)

The recurrent nova RS Oph: A possible scenario for type Ia supernovae

The recurrent nova RS Oph experienced an outburst in 2006, 21 years after its previous explosion in 1985, as expected. It was observed at almost all wavelengths, and important information about its properties is still being extracted. We present theoretical models of the explosion of this fascinating object, which indicate that the mass of the accreting white dwarf should be very close to the Chandrasekhar mass, to allow for such a short recurrence period. In addition, since models suggest that this nova ejects less mass than it accretes, it is an excellent candidate for a thermonuclear supernova explosion, in about $10^5-10^7$ years from now. We also analyze the emission of soft gamma-rays by RS Oph detected with the BAT instrument onboard Swift, and with the PCA onboard RXTE. We rule out that this emission has its origin in radioactive decays in the expanding nova envelope.Comment: 10 pages, 2 figures, to be published in New Astronomy Review

Action scales for quantum decoherence and their relation to structures in phase space

A characteristic action $\Delta S$ is defined whose magnitude determines some properties of the expectation value of a general quantum displacement operator. These properties are related to the capability of a given environmental `monitoring' system to induce decoherence in quantum systems coupled to it. We show that the scale for effective decoherence is given by $\Delta S\approx\hbar$. We relate this characteristic action with a complementary quantity, $\Delta Z$, and analyse their connection with the main features of the pattern of structures developed by the environmental state in different phase space representations. The relevance of the $\Delta S$-action scale is illustrated using both a model quantum system solved numerically and a set of model quantum systems for which analytical expressions for the time-averaged expectation value of the displacement operator are obtained explicitly.Comment: 12 pages, 3 figure

Insulin degradation by adipose tissue is increased in human obesity

White adipose tissue samples from obese and lean patients were used for the estimation ofinsulin protease and insulin:glutathione transhydrogenase using 1251-labeled insulin. There was no activity detected in the absence of reduced glutathione, which indicates that insulin is cleaved in human adipose "tissue through reduction of the disulfide bridge between the chains. O bese patients showed higher transhydrogenase activity (per U tissue protein wt, per U tissue wt, and in the total adipose tissue mass) than the lean group. There is a significant correlation between the activity per U tissue wt, and protein and total activity in the whole adipose tissue with respect to body mass index, with a higher activity in obese patients. The potential ofinsulin cleavage by adipose tissue in obese patients was a mean 5.6-fold higher than that in controla. The coexistence of high insulinemia and high cleavage capability implies that insulin secretion and turnover are increased in the o bese. Thus, white adipose tissue may be crucial in the control of energy availability through modulation ofinsulin cleavage