HST and ground-based eclipse observations of V2051 Ophiuchi: Binary parameters

We report on high-speed eclipse photometry of the dwarf nova V2051 Oph while it was in a low brightness state, at B ~ 16.2 mag. In comparison to the average IUE spectra, the ultraviolet continuum and emission lines appear reduced by factors of, respectively, ~4 and ~5. Flickering activity is mostly suppressed and the lightcurve shows the eclipse of a compact white dwarf at disc centre which contributes ~60 per cent of the total light at 3900--4300 A. We use measurements of contact phases in the eclipse lightcurve to derive the binary geometry and to estimate masses and relevant dimensions. We find a mass ratio of q= 0.19+/-0.03 and an inclination of i= 83+/-2 degrees. The masses of the component stars are M_1 = 0.78+/-0.06 M_dot and M_2 = 0.15+/-0.03 M_dot. Our photometric model predicts K_1 = 83+/-12 km/s and K_2= 435+/-11 km/s. The predicted value of K_1 is in accordance with the velocity amplitude obtained from the emission lines after a correction for asymmetric line emission in the disc is made (Watts et al. 1986). The secondary of V2051 Oph is significantly more massive than the secondaries of the other ultra-short period dwarf novae. V2051 Oph is probably a relatively young system, whose secondary star had not enough time to evolve out of thermal equilibrium.Comment: 16 pages, 7 postscript figures, coded using MNRAS latex style. To appear in Monthly Notices of the Royal Astronomical Society. Revised version with changes in section 4.3. For related papers and files see ftp://fsc01.fsc.ufsc.br/pub/bap and http://www.fsc.ufsc.br/~astr

High-velocity hot CO emission close to Sgr A*: Herschel/HIFI submillimeter spectral survey toward Sgr A*

The properties of molecular gas, the fuel that forms stars, inside the cavity of the circumnuclear disk (CND) are not well constrained. We present results of a velocity-resolved submillimeter scan (~480 to 1250 GHz}) and [CII]158um line observations carried out with Herschel/HIFI toward Sgr A*; these results are complemented by a ~2'x2' CO (J=3-2) map taken with the IRAM 30 m telescope at ~7'' resolution. We report the presence of high positive-velocity emission (up to about +300 km/s) detected in the wings of CO J=5-4 to 10-9 lines. This wing component is also seen in H2O (1_{1,0}-1_{0,1}) a tracer of hot molecular gas; in [CII]158um, an unambiguous tracer of UV radiation; but not in [CI]492,806 GHz. This first measurement of the high-velocity CO rotational ladder toward Sgr A* adds more evidence that hot molecular gas exists inside the cavity of the CND, relatively close to the supermassive black hole (< 1 pc). Observed by ALMA, this velocity range appears as a collection of CO (J=3-2) cloudlets lying in a very harsh environment that is pervaded by intense UV radiation fields, shocks, and affected by strong gravitational shears. We constrain the physical conditions of the high positive-velocity CO gas component by comparing with non-LTE excitation and radiative transfer models. We infer T_k~400 K to 2000 K for n_H~(0.2-1.0)x10^5 cm^-3. These results point toward the important role of stellar UV radiation, but we show that radiative heating alone cannot explain the excitation of this ~10-60 M_Sun component of hot molecular gas inside the central cavity. Instead, strongly irradiated shocks are promising candidates.Comment: Accepted for publication in A&A Letters ( this v2 includes corrections by language editor

Composição florística da vegetação arbórea nativa do sub-bosque de 30 povoamentos comerciais de Eucalyptus spp do sudeste do Brasil.

Foram revisados 30 trabalhos que observaram a diversidade de espécies arbóreas no sub-bosque de plantios comerciais de Eucalyptus spp. A área média dos fragmentos avaliados é de 21 ha e a diversidade de espécies arbóreas é de 56 ind/ha. O menor fragmento possui 0,3 ha e o maior 150 ha. Ao todo foram encontrados 76 famílias, 282 gêneros e 788 espécies. Apesar da carência de trabalhos e do pequeno tamanho dos fragmentos, o número de espécies encontradas é relevante e qualifica esse tipo de fragmento florestal como útil para o surgimento, desenvolvimento e manutenção de espécies florestais nativas. As cinco espécies que mais ocorreram foram: Casearia sylvestris Sw., Zanthoxylum rhoifolium Lam., Siparuna guianensis Aubl., Copaifera langsdorffii Desf. e Piptadenia gonoacantha (Mart.) Macbr. Foram encontradas 34 espécies com algum grau de ameaça de extinção de acordo com a lista de espécies ameaçadas do Instituto de Botânica de São Paulo. Comprovando a importância desses fragmentos para o desenvolvimento e manutenção de espécies ameaçadas. De todas as espécies relacionadas somente 15% são pioneiras. Mostrando que o sub-bosque favorece o desenvolvimento de espécies mais tardias. A forma de dispersão de sementes predominante é a zoocoria, onde acima de 60% das espécies apresentam essa característica. Esse fato mostra a importância da presença de fragmentos nativos e animais dispersores próximos as áreas de Eucaliptus. Conclui-se que os fragmentos de sub-bosque são capazes de manter uma diversidade elevada de espécies lenhosas nativas. Verifica-se a possibilidade de se recuperar áreas florestais por meio da retirada dos indivíduos de Eucalyptus, conciliando essa forma de recuperação com a Lei Estadual Paulista nº 12.927/2008 e o Decreto nº 53.939/2009 que permitem a compensação da Reserva Legal através do plantio de espécies exóticas intercaladas às nativas, oferecendo uma alternativa economicamente viável para a sua recomposição

CasaClima qualty seals – a key to sustainable buildings

For CasaClima, sustainability in buildings is a holistic concept, which not only evaluates the energy efficiency but goes further by considering a broad spectrum of aspects. At the roots of the CasaClima sustainability seals lays the proven CasaClima energy efficiency certification extended by a set of criteria aimed at reducing the waste of natural resources, thereby limiting the environmental impact and assuring the wellbeing of the people who live or work in the building. The CasaClima Agency, a public and independent body, deals with all aspects related to the quality assurance of the entire construction process from the planning, to on-site audits and finally the issuing of the CasaClima certification.Tema 5: Arquitectura ambientalmente consciente.Facultad de Arquitectura y Urbanism

Automated Quantitative Analysis of Nerve Fiber Conduction Velocity

poster abstractThe baroreflex (BRX) is essential for reliable autonomic control of arterial blood pressure. Central to BRX function is a rapid, negative feedback control of heart rate. Arterial pressure sensors known as baroreceptors (BR) encode heart rate and blood pressure information into patterns of neural discharge that is conveyed to the central nervous system via a network of sensory afferent nerve fibers. These BR fibers are broadly classified as myelinated A-fibers with diameters in the range of 1-10 μm and unmyelinated Cfibers with diameters typically less than 1 μm. Fiber diameter and conduction velocity are related with the large A-fibers being much faster (> 10 m/sec) than the smaller diameter C-fibers (< 1 m/sec). Recently, our lab has documented an additional phenotype of myelinated BR afferents termed Ah-fibers that are notably present in female; but only rarely observed in male rats. In response to an electrical stimulus, the nerve fibers produce a compound action potential (CAP) that propagates away from the stimulation site. The CAP of each fiber type is observable in the evoked waveform on account of the differing conduction velocities. As Ah-fibers have conduction velocities in the range of 10 m/sec - 2 m/sec, the resulting CAP is clearly separated in time from the faster A-fibers and much slower C-fibers. Root-mean-square analysis of these distinct time segments provides a quantitative measure of the total signal energy from each of the A-, Ah-, and C-type fibers. This project sought to create MATLAB scripts that would import nerve recording files from both male and female rats and automate the energy analysis in an efficient and reliable manner. Doing so not only facilitates the analysis of these large data files, but also reduces the possibility for biases and errors that can occur during a manual measurement of nerve activity

Métodos para evaluar interacciones entre cuerpos de agua en un humedal y aplicación en dos casos de estudio

La comprensi&oacute;n de la din&aacute;mica de ecosistemas dependientes del recurso h&iacute;drico subterr&aacute;neo, como pueden llegar a serlo algunos humedales, parte del conocimiento del sistema hidrol&oacute;gico. Para alcanzar esta meta se aplica una serie de m&eacute;todos y procedimientos de an&aacute;lisis que comprenden la caracterizaci&oacute;n hi-drogeol&oacute;gica, la delimitaci&oacute;n del &aacute;rea de captura de agua hacia el humedal, el monitoreo piezom&eacute;trico, la rea-lizaci&oacute;n de balances de masas. La modelaci&oacute;n num&eacute;rica, los an&aacute;lisis hidrogeoqu&iacute;micos y los m&eacute;todos isot&oacute;pi-cos permiten refinar y validar los modelos conceptuales. En el marco del proyecto Hydrochemical and isotopic techniques for assessment hidrological proccesses on wetlands, promovido entre los a&ntilde;os 2006 y 2011 por la Agencia Internacional de Energ&iacute;a At&oacute;mica (IAEA), Colombia y Argentina compartieron conoci-miento y experiencias para entender la din&aacute;mica de los humedales Ci&eacute;naga Colombia y La Salada. En este texto se resumen aspectos metodol&oacute;gicos y los resultados de los dos casos de estudio considerados.The Understanding of ecosystem dynamics, for example the wetlands, depends of the knowledge of the hydrologic system. Many techniques can be used in order to obtain a good conceptual mod-el of the wetlands and its catchment area: hydrogeology, numerical modeling, hydrogeochemestry, and iso-tope hydrology. researchers of Argentina and Colombia studied -According with the project: ―Hydrochemical and isotopic techniques for assessment hidrological proccesses on wetlands‖ (IAEA, 2006 to 2011)- two wet-lands hydrogeology dependent: La salada Pond and Cienaga Colombia Weltand. These projects used method-ologies similar and they obtained validated hydrological models