187 research outputs found

    Photometric Variability of the Disk Integrated Infrared Emission of the Earth

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    We present an analysis of the global-integrated mid-infrared emission flux of the Earth based on data derived from satellite measurements. We have studied the photometric annual, seasonal, and rotational variability of the thermal emission of the Earth to determine which properties can be inferred from the point-like signal. We find that the analysis of the time series allows us to determine the 24 hr rotational period of the planet for most observing geometries, due to large warm and cold areas, identified with geographic features, which appear consecutively in the observer's planetary view. However, the effects of global-scale meteorology can effectively mask the rotation for several days at a time. We also find that orbital time series exhibit a seasonal modulation, whose amplitude depends strongly on the latitude of the observer but weakly on its ecliptic longitude. As no systematic difference of brightness temperature is found between the dayside and nightside, the phase variations of the Earth in the infrared range are negligible. Finally, we also conclude that the phase variation of a spatially unresolved Earth-Moon system is dominated by the lunar signal.Comment: 11 pages, 10 figures. Accepted for publication in Ap

    Climate vulnerability, impacts and adaptation in Central and South America coastal areas

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    © 2019 Elsevier B.V. Low-Elevation Coastal Zones in Central and South America are exposed to climate-related hazards (sea-level rise, climate variability and storms) which threaten the assets (people, resources, ecosystems, infrastructure, and the services they provide), and are expected to increase due to climate change. A non-systematic review is presented focusing on vulnerability elements, impacts, constraints to adaptation, and their possible strategies. The analysis emphasises the Intergovernmental Panel on Climate Change Reasons for Concern (e.g., threatened systems, extreme events, aggregated impacts, and critical thresholds), particularly on sea-level rise, degradation of mangroves, and invasive alien species in Central and South America focusing on case studies from Uruguay and Venezuela. Despite recent advances in coastal adaptation planning in Central and South America, there is an adaptation deficit in the implementation of measures and strategies against climate-related hazards, such as sea-level rise. Adaptation constraints are linked with poverty, resource allocation, lack of political will, and lack of early warning systems for climate-related hazards. Non-structural adaptation measures such as community-based adaptation and ecosystem-based adaptation are not fully mainstreamed into national plans yet. Government-level initiatives (e.g. National Adaptation Programmes of Action) are being developed, but a few are already implemented. In addition to specific thematic measures, the implementation of non-structural approaches, National Adaptation Programmes of Action and early warning systems, based on the reasons for concern, should foster adaptive capacity in coastal areas

    Long-term benefits of nevirapine-containing regimens: multicenter study with 506 patients, followed-up a median of 9 years

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    [Abstract] OBJECTIVE: To evaluate long-term outcomes in patients maintaining a nevirapine (NVP)-based regimen. METHODS: Retrospective, multicenter, cohort study including patients currently receiving an NVP regimen that had been started at least 5 years previously. Demographic, clinical, and analytical variables were recorded. RESULTS: Median follow-up was 8.9 (5.7-11.3) years. Baseline characteristics: 74% men, 47 years old, 36% drug users, 40% AIDS, 40% HCV+, 51.4% detectable HIV-1 viral load, CD4 count 395 (4-1,421)/μL, 19% CD4 3.37 mmol/L significantly decreased in a subsample with available values. A significant decrease in transaminases, alkaline phosphatase, and Fib4 score was observed, mainly in HCV+ and ARV-naive patients. CONCLUSIONS: In patients who tolerate NVP therapy, (even those with HCV coinfection), long term benefits may be significant in terms of a progressive improvement in general health status markers and CD4 response, a favorable lipid profile, and good liver tolerability

    Mapping Exoplanets

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    The varied surfaces and atmospheres of planets make them interesting places to live, explore, and study from afar. Unfortunately, the great distance to exoplanets makes it impossible to resolve their disk with current or near-term technology. It is still possible, however, to deduce spatial inhomogeneities in exoplanets provided that different regions are visible at different times---this can be due to rotation, orbital motion, and occultations by a star, planet, or moon. Astronomers have so far constructed maps of thermal emission and albedo for short period giant planets. These maps constrain atmospheric dynamics and cloud patterns in exotic atmospheres. In the future, exo-cartography could yield surface maps of terrestrial planets, hinting at the geophysical and geochemical processes that shape them.Comment: Updated chapter for Handbook of Exoplanets, eds. Deeg & Belmonte. 17 pages, including 6 figures and 4 pages of reference

    Neutron-induced fission cross sections of Th 232 and U 233 up to 1 GeV using parallel plate avalanche counters at the CERN n_TOF facility

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    The neutron-induced fission cross sections of 232 Th and 233 U were measured relative to 235 U in a wide neutron energy range up to 1 GeV (and from fission threshold in the case of 232 Th , and from 0.7 eV in case of 233 U ), using the white-spectrum neutron source at the CERN Neutron Time-of-Flight (n_TOF) facility. Parallel plate avalanche counters (PPACs) were used, installed at the Experimental Area 1 (EAR1), which is located at 185 m from the neutron spallation target. The anisotropic emission of fission fragments were taken into account in the detection efficiency by using, in the case of 233 U , previous results available in EXFOR, whereas in the case of 232 Th these data were obtained from our measurement, using PPACs and targets tilted 45 ° with respect to the neutron beam direction. Finally, the obtained results are compared with past measurements and major evaluated nuclear data libraries. Calculations using the high-energy reaction models INCL + + and ABLA07 were performed and some of their parameters were modified to reproduce the experimental results. At high energies, where no other neutron data exist, our results are compared with experimental data on proton-induced fission. Moreover, the dependence of the fission cross section at 1 GeV with the fissility parameter of the target nucleus is studied by combining those ( p , f ) data with our ( n , f ) data on 232 Th and 233 U and on other isotopes studied earlier at n_TOF using the same experimental setup.Peer ReviewedArticle escrit per 81 autors/autores: D. Tarrío , L. Tassan-Got, I. Duran, L. S. Leong, C. Paradela, L. Audouin, E. Leal-Cidoncha, C. Le Naour, M. Caamaño, A. Ventura, S. Altstadt, J. Andrzejewski, M. Barbagallo, V. Bécares, F. Becvá ˇ ˇr,F. Belloni, E. Berthoumieux, J. Billowes, V. Boccone, D. Bosnar, M. Brugger, M. Calviani, F. Calviño, D. Cano-Ott, C. Carrapiço, F. Cerutti, E. Chiaveri,M. Chin, N. Colonna, G. Cortés, M. A. Cortés-Giraldo, M. Diakaki, C. Domingo-Pardo, N. Dzysiuk, C. Eleftheriadis, A. Ferrari, K. Fraval, S. Ganesan, A. R. García, G. Giubrone, M. B. Gómez-Hornillos, I. F. Gonçalves, E. González-Romero,E. Griesmayer, C. Guerrero, F. Gunsing, P. Gurusamy, D. G. Jenkins, E. Jericha, Y. Kadi, F. Käppeler,† D. Karadimos, P. Koehler, M. Kokkoris, M. Krticka, J. Kroll, C. Langer, C. Lederer, H. Leeb, R. Losito, A. Manousos, J. Marganiec, T. Martínez, C. Massimi, P. F. Mastinu,M. Mastromarco, M. Meaze, E. Mendoza, A. Mengoni, P. M. Milazzo, F. Mingrone, M. Mirea,,† W. Mondalaers, A. Pavlik, J. Perkowski, A. Plompen, J. Praena, J. M. Quesada, T. Rauscher, R. Reifarth, A. Riego, M. S. Robles, F. Roman, C. Rubbia, R. Sarmento, P. Schillebeeckx,S. Schmidt, G. Tagliente, J. L. Tain, A. Tsinganis, S. Valenta, G. Vannini, V. Variale, P. Vaz, R. Versaci, M. J. Vermeulen, V. Vlachoudis, R. Vlastou,A. Wallner, T. Ware, M. Weigand, C. Weiß, T. J. Wright, P. ŽugecPostprint (published version

    High accuracy 234U(n,f) cross section in the resonance energy region

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    New results are presented of the 234U neutron-induced fission cross section, obtained with high accuracy in the resonance region by means of two methods using the 235U(n,f) as reference. The recent evaluation of the 235U(n,f) obtained with SAMMY by L. C. Leal et al. (these Proceedings), based on previous n-TOF data [1], has been used to calculate the 234U(n,f) cross section through the 234U/235U ratio, being here compared with the results obtained by using the n-TOF neutron flux

    Guía práctica para el estudio del crecimiento de especies demersales en el Área ICES

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    Versión revisada 05-02-2015En el documento se presenta una síntesis de los métodos empleados para estudiar el crecimiento y la edad, mediante estructuras calcificadas (otolitos y vértebras), de las especies ícticas de interés comercial para la flota española en el área del ICES. El estudio de estas especies forma parte del requerimiento que la Comisión Europea ha establecido para el Programa Español de Recopilación, Gestión y Uso de Datos Pesqueros (PNDB) en base a los desembarcos nacionales, según establece la normativa vigente de la Unión Europea (UE). En este Programa está involucrado el Instituto Español de Oceanografía (IEO), y entre otros el proyecto BIODEMER, desarrollado en el Centro Oceanográfico de Vigo. Las especies objeto de estudio en este proyecto son: merluza ("Merluccius merluccius"), abadejo ("Pollachius pollachius"), congrio ("Conger conger"), faneca ("Trisopterus luscus"), gallineta ("Helicolenus dactylopterus"), locha ("Phycis blennoides"), maruca ("Molva molva"), maruca española ("Molva macrophthalma"), mendo ("Glyptocephalus cynoglossus"); incluyendo las especies de descarte: arete ("Chelidonichthys cuculus") y goyeta ("Microchirus variegatus"). Para complementar este documento se ha adjuntado el anexo: Fichas técnicas de Biología y crecimiento de 11 especies demersales en el área ICES, en el que se detallan para cada especie los protocolos aplicados en la interpretación de la edad. Para cada caso se incluye una revisión de la bibliografía existente, así como de los talleres e intercambios realizados sobre estudios de crecimiento y edad

    Measurement of the 240Pu(n,f) cross-section at the CERN n-TOF facility : First results from experimental area II (EAR-2)

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    The accurate knowledge of the neutron-induced fission cross-sections of actinides and other isotopes involved in the nuclear fuel cycle is essential for the design of advanced nuclear systems, such as Generation-IV nuclear reactors. Such experimental data can also provide the necessary feedback for the adjustment of nuclear model parameters used in the evaluation process, resulting in the further development of nuclear fission models. In the present work, the 240Pu(n,f) cross-section was measured at CERN's n-TOF facility relative to the well-known 235U(n,f) cross section, over a wide range of neutron energies, from meV to almost MeV, using the time-of-flight technique and a set-up based on Micromegas detectors. This measurement was the first experiment to be performed at n-TOF's new experimental area (EAR-2), which offers a significantly higher neutron flux compared to the already existing experimental area (EAR-1). Preliminary results as well as the experimental procedure, including a description of the facility and the data handling and analysis, are presented
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