308 research outputs found

    A hardware library for sensors/actuators interfaces in sensor networks

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    Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. J. Portilla, J. L. Buron, T. Riesgo, and A. de Castro, "A hardware library for sensors/actuators interfaces in sensor networks", and 13th IEEE International Conference on Electronics, Circuits and Systems, ICECS 2006, Nice (France), 2006, pp. 1244 - 1247.Sensor networks have reached a great relevance during the last years. The idea is to use a high number of nodes measuring different physical parameters in several environments, which implies different research challenges (low power consumption, communication protocols, platform hardware design, etc). There is a tendency to use modular hardware nodes in order to make easier rapid prototyping as well as to be able to redesign faster and reuse part of the hardware modules. One of the main obstacles for rapid prototyping is that sensors present heterogeneous interfaces. In this paper, a VHDL library for sensors/actuators interfaces is proposed in order to have a set of different sensor interfaces that include the most common in the sensors/actuators world, enabling a rapid connection to a new sensor/actuator

    Living together, feeding apart. Trophic ecology of three demersal sharks in the north-east Atlantic

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    Feeding habits, diets and trophic relationships among three demersal sharks (Galeus melastomus Rafinesque, 1810; Etmopterus spinax (Linnaeus, 1758); and Scyliorhinus canicula (Linnaeus, 1758)) from the Porcupine Bank, Northeast Atlantic were studied. The stomach content analysis revealed differences between the diet of the three species, with a clear preference for benthonic preys in the case of S. canicula, and benthopelagic preys in the case of E. spinax and G. melastomus. The results of this study provide new knowledge about the ecological role of these species in the Porcupine Bank and will be of vital importance for their management and conservation of these species

    Cooperation between passive and active silicon transporters clarifies the ecophysiology and evolution of biosilicification in sponges

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    Este artĂ­culo contiene 14 pĂĄginas, 6 figuras.The biological utilization of dissolved silicon (DSi) influences ocean ecology and biogeochemistry. In the deep sea, hexactinellid sponges are major DSi consumers that remain poorly understood. Their DSi consumption departs from the Michaelis-Menten kinetics of shallow-water demosponges and appears particularly maladapted to incorporating DSi from the modest concentrations typical of the modern ocean. Why did sponges not adapt to the shrinking DSi availability that followed diatom expansion some 100 to 65 million years ago? We propose that sponges incorporate DSi combining passive (aquaglyceroporins) and active (ArsB) transporters, while only active transporters (SITs) operate in diatoms and choanoflagellates. Evolution of greater silicon transport efficiency appears constrained by the additional role of aquaglyceroporins in transporting essential metalloids other than silicon. We discuss the possibility that lower energy costs may have driven replacement of ancestral SITs by less efficient aquaglyceroporins, and discuss the functional implications of conservation of aquaglyceroporin-mediated DSi utilization in vertebrates.This research was completed mostly by funds from the SponGES H2020 grant (BG-01-2015.2, agreement number 679849-2) to M.M. and A.R. and from Fisheries and Oceans Canada Strategic Program for Ecosystem-Based Research and Advice (SPERA) and International Governance Strategy (IGS) projects awarded to L.B. and E.K. This study also benefitted from funding by a PBS grant (MINECO CTM2015-67221-R) to M.M. This study is in memory of Hans Tore Rapp, who passed away on 7 March 2020, and who was the main coordinator of the H2020 SponGES project that has made this research possible.Peer reviewe

    Spectroscopy of planetary nebulae in M33

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    Spectroscopic observations of 48 emission-line objects of M33 have been obtained with the multi-object, wide field, fibre spectrograph AF2/WYFFOS at the 4.2m WHT telescope (La Palma, Spain). Line intensities and logarithmic extinction, cbeta, are presented for 42 objects. Their location in the Sabbadin & D'Odorico diagnostic diagram (Halpha/[SII] vs Hlapha/[NII]) suggests that >70% of the candidates are Planetary Nebulae (PNe). Chemical abundances and nebular physical parameters have been derived for the three of the six PNe where the 4363A [OIII] emission line was measurable. These are disc PNe, located within a galactocentric distance of 4.1 kpc, and, to date, they are the farthest PNe with a direct chemical abundance determination. No discrepancy in the Helium, Oxygen and Argon abundances has been found in comparison with corresponding abundances of PNe in our Galaxy. Only a lower limit to the sulphur abundance has been obtained since we could not detect any [SIII] line. N/H appears to be lower than the Galactic value; some possible explanations for this under-abundance are discussed.Comment: 18 pages, 1 JPEG figure and 3 Postscript figures, Accepted for publication in A&

    El virus de la fiebre amarilla “un virus científicamente olvidado”

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    La fiebre amarilla es una enfermedad viral propia de regiones subtropicales que afecta principalmente el hĂ­gado produciendo hemorragias agudas y daños graves a nivel del tejido; es causada por un virus perteneciente al gĂ©nero Flavivirus, y es transmitida en el nĂșcleo urbano por el mosquito Aedes aegypti, y selvĂĄticamente, por mosquitos del gĂ©nero Haemagogus. En Colombia, se presentaron 20 casos en el 2005 de los cuales el 65% fue letal (OMS, 2006) (*). Sobre la fiebre amarilla, se logrĂł un control importante, sin embargo, actualmente es considerada como una enfermedad reemergente debido a mĂșltiples factores que han venido aumentando a travĂ©s de los Ășltimos veinte años, tales como la amplia diseminaciĂłn del vector, la deforestaciĂłn, el aumento de la poblaciĂłn susceptible no vacunada, diversos fenĂłmenos climĂĄticos (FenĂłmeno del PacĂ­fico, por ejemplo), y la falta de programas de vigilancia epidemiolĂłgica. En paĂ­ses como el nuestro, la situaciĂłn se agudiza con el desplazamiento forzado de la poblaciĂłn, la explotaciĂłn de las zonas selvĂĄticas vĂ­rgenes, la violencia y el narcotrĂĄfico. A pesar de la disponibilidad de una vacuna con una alta eficacia, la fiebre amarilla continĂșa siendo una causa importante de morbilidad y mortalidad en regiones tropicales de África y de AmĂ©rica del Sur (OMS, 2006) (**). La metodologĂ­a de producciĂłn de la vacuna estĂĄ muy bien definida, es eficiente, e incluye un estricto control de calidad sobre los efectos neurolĂłgicos del virus, induce un periodo de protecciĂłn de diez años con una sola dosis y es, ademĂĄs, barata. No obstante, desde 1996 se han reconocido casos de la enfermedad, la cual no sĂłlo es neurolĂłgica, sino, tambiĂ©n, viscerotrĂłpica (afecciĂłn hepĂĄtica principalmente), como consecuencia de la vacunaciĂłn. Los efectos adversos producidos por la vacuna, y que hoy en dĂ­a se conocen gracias a la implantaciĂłn de programas de seguimiento postvacunal, no tienen una explicaciĂłn cientĂ­fica, en parte, por la aceptaciĂłn absoluta que hubo sobre su eficacia y su seguridad desde que se iniciĂł su utilizaciĂłn en seres humanos; sin embargo, el problema mismo ha despertado un interĂ©s mundial por el desarrollo de una vacuna que no presente ningĂșn riesgo para el hombre, lo cual conlleva a la necesidad de conocer cientĂ­ficamente las causas que originan esta situaciĂłn, como un prerrequisito para abordar adecuadamente cualquier estrategia de mejoramiento de la vacuna actual. Atendiendo a esta necesidad, el grupo de BioquĂ­mica y BiotecnologĂ­a en Salud de la Facultad de Medicina de la Universidad del Rosario ha tomado el virus de la fiebre amarilla como modelo de investigaciĂłn, buscando dilucidar, por quĂ© la vacuna estĂĄ produciendo la enfermedad

    Candidate planetary nebulae in the IPHAS photometric catalogue

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    Original article can be found at: http://www.aanda.org/ Copyright European Southern Observatory. DOI: 10.1051/0004-6361/200912002Context. We have carried out a semi-automated search for planetary nebulae (PNe) in the INT photometric H-alpha survey (IPHAS) catalogue. We present the PN search and the list of selected candidates. We cross correlate the selected candidates with a number of existing infrared galactic surveys in order to gain further insight into the nature of the candidates. Spectroscopy of a subset of objects is used to estimate the number of PNe present in the entire candidate list. Aims. The overall aim of the IPHAS PN project is to carry out a deep census of PNe in the northern Galactic plane, an area where PN detections are clearly lacking. Methods. The PN search is carried out on the IPHAS photometric catalogue. The candidate selection is based on the IPHAS and 2MASS/UKIDSS colours of the objects and the final candidate selection is made visually. Results. From the original list of ~600 million IPHAS detections we have selected a total of 1005 objects. Of these, 224 are known objects, leaving us with 781 PN candidates. Based on the initial follow-up spectroscopy, we expect the list to include very young and proto-PNe in addition to genuine, normal PNe (~16%) and emission line objects other than PNe. We present additional criteria to select the most probable PN candidates from our candidate list.Peer reviewe

    The metallicity gradient of M 33: chemical abundances of HII regions

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    We present spectroscopic observations of a sample of 72 emission-line objects, including mainly HII regions, in the spiral galaxy M 33. Spectra were obtained with the multi-object, wide field spectrograph AF2/WYFFOS at the 4.2m WHT telescope. Line intensities, extinction, and electron density were determined for the whole sample of objects. The aim of the present work was to derive chemical and physical parameters of a set of HII regions, and from them the metallicity gradient. Electron temperatures and chemical abundances were derived for the 14 HII regions where both [OII] and [OIII] emission line fluxes were measured, including the electron temperature sensitive emission line [OIII] 436.3 nm and in a few cases [NII] 575.5 nm. The ionization correction factor (ICF) method was used to derive the total chemical abundances. The presence of abundance gradients was inferred from the radial behaviour of several emission-line ratios, and accurately measured from chemical abundances directly derived in 14 HII regions. The oxygen abundances of our HII regions, located in the radial region from ~2 to ~7.2 kpc, gave an oxygen gradient -0.054+/-0.011 dex/kpc The overall oxygen gradient for M 33 obtained using ours and previous oxygen determinations in a large number of HII regions with direct electron temperature determination as well as abundance in young stars presented a two slope shape: -0.19 dex/kpc for the central regions (R<3kpc), and -0.038dex/kpc for the outer regions (R>=3kpc).Comment: 16 pages, 14 figures, A&A accepted 10/05/200

    New young planetary nebulae in IPHAS

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    Original article can be found at: http://www.aanda.org/ Copyright The European Southern Observatory. DOI: 10.1051/0004-6361/200811575Aims. We search for very small-diameter galactic planetary nebulae (PNe) representing the earliest phases of PN evolution. The IPHAS catalogue of H-emitting stars provides a useful basis for this study since all sources present in this catalogue must be of small angular diameter. Methods. The PN candidates are selected based on their location in two colour-colour diagrams: IPHAS (r' - H) vs. (r' - i'), and 2MASS (J - H) vs. (H - ). Spectroscopic follow-up was carried out on a sample of candidates to confirm their nature. Results. We present a total of 83 PN candidates. We were able to obtain spectra or find the classification from the literature for 35 candidates. Five of these objects are likely to be new PNe, including one large bipolar PN discovered serendipitously close to an emission-line star. PN distances deduced from extinction-distance relations based on IPHAS field-star photometry are presented for the first time. These yield distance estimates for our objects in the range 2 kpc and 6 kpc. From the data in hand, we conclude that four of the discovered objects are probably young PNe.Peer reviewe

    Comparative description of ten transcriptomes of newly sequenced invertebrates and efficiency estimation of genomic sampling in non-model taxa

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    Traditionally, genomic or transcriptomic data have been restricted to a few model or emerging model organisms, and to a handful of species of medical and/or environmental importance. Next-generation sequencing techniques have the capability of yielding massive amounts of gene sequence data for virtually any species at a modest cost. Here we provide a comparative analysis of de novo assembled transcriptomic data for ten non-model species of previously understudied animal taxa.Peer reviewe
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