79 research outputs found

    Influences of synoptic situation and teleconnections on fog-water collection in the Mediterranean Iberian Peninsula, 2003-2012

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    Fog-water collection has been widely analysed for its quantification and potential uses; however, there are few studies assessing the synoptic conditions and largescale teleconnection patterns that affect its occurrence. Focusing on the Mediterranean Iberian Peninsula, this work aims to analyse the synoptic patterns, both at surface level and 850 hPa geopotential height, that most likely to favour fogwater collection, and to quantify the relationship between fog-water collection and the NAOi (North Atlantic Oscillation index), MOi (Mediterranean Oscillation index) as well as WeMOi (Western Mediterranean Oscillation index) teleconnection patterns. For this purpose, daily fog-water observations from a dense network of 23 fog-water collectors located along the Mediterranean Iberian Peninsula for 2003-2012 were analysed in relation to synoptic patterns and the threeteleconnection indices. The major findings are: (a) The most favourable synoptic patterns for fog-water collection are maritime advections carrying humidity from the Mediterranean basin, and cyclonic circulations, whereas anti-cyclonic situations generally led to large number of foggy days with low fog-collection rates. (b) In terms of winds at 850 hPa, the most favourable low-level flows for fogwater collection are associated with strong winds (>5.1 m s−1) from theMediterranean. Atlantic winds generally cause a greater number of fog days than Mediterranean winds, with less fog-water collection rates. (c) WeMOi has the greatest influence on fog-water collection, mainly during winter and spring months, with statistically significant negative relationships for most of the stations. MOi also shows a great influence, with a large number of statistically significant negative correlations, mainly during the same months as WeMOi. Lastly, NAOi presented the lowest and no significant negative correlations with fog-water collection

    Preconditioned iterative methods for convection diffusion and related boundary value problems

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    AbstractWe develop and analyze preconditioners for the iterative solution of the system of equations arising from the discretization of multi-dimensional singularity perturbed boundary value problems. This includes a class of convection diffusion models. The choice of preconditioner is crucial for the efficient solution of the system of equations. In particular, it is necessary to choose a preconditioner that substantially reduces the condition number κ both for small grid size h and for large values of the parameter K multiplying the convection terms. A class of preconditioners is analyzed that is inexpensive to implement and for which κ = 0(1) as h→0 and κ = (1 + K12) as K → ∞ for some convection diffusion problems with positive definite symmetric part. This result is then used to develop an algorithm with work estimate 0(1 + K12as K → ∞ for a more general class of convection diffusion problems including those with indefinite symmetric part. Numerical experiments using a symmetric multigrid preconditioner demonstrate the effectiveness of the numerical method even for large problems

    The ambivalent shadow of the pre-Wilsonian rise of international law

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    The generation of American international lawyers who founded the American Society of International Law in 1906 and nurtured the soil for what has been retrospectively called a “moralistic legalistic approach to international relations” remains little studied. A survey of the rise of international legal literature in the U.S. from the mid-19th century to the eve of the Great War serves as a backdrop to the examination of the boosting effect on international law of the Spanish American War in 1898. An examination of the Insular Cases before the US Supreme Court is then accompanied by the analysis of a number of influential factors behind the pre-war rise of international law in the U.S. The work concludes with an examination of the rise of natural law doctrines in international law during the interwar period and the critiques addressed.by the realist founders of the field of “international relations” to the “moralistic legalistic approach to international relation

    ESPRESSO: The next European exoplanet hunter

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    The acronym ESPRESSO stems for Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations; this instrument will be the next VLT high resolution spectrograph. The spectrograph will be installed at the Combined-Coud\'e Laboratory of the VLT and linked to the four 8.2 m Unit Telescopes (UT) through four optical Coud\'e trains. ESPRESSO will combine efficiency and extreme spectroscopic precision. ESPRESSO is foreseen to achieve a gain of two magnitudes with respect to its predecessor HARPS, and to improve the instrumental radial-velocity precision to reach the 10 cm/s level. It can be operated either with a single UT or with up to four UTs, enabling an additional gain in the latter mode. The incoherent combination of four telescopes and the extreme precision requirements called for many innovative design solutions while ensuring the technical heritage of the successful HARPS experience. ESPRESSO will allow to explore new frontiers in most domains of astrophysics that require precision and sensitivity. The main scientific drivers are the search and characterization of rocky exoplanets in the habitable zone of quiet, nearby G to M-dwarfs and the analysis of the variability of fundamental physical constants. The project passed the final design review in May 2013 and entered the manufacturing phase. ESPRESSO will be installed at the Paranal Observatory in 2016 and its operation is planned to start by the end of the same year.Comment: 12 pages, figures included, accepted for publication in Astron. Nach

    Energia solar disponible en la ciudad de México

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    CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: En el año 2014, con recursos del Instituto de Ciencia y Tecnología del Distrito Federal (PINVII-7), se instalaron 10 piranómetros en las estaciones de la Red Automática de Monitoreo Atmosférico (RAMA), de la Secretaría del Medio Ambiente de la Ciudad de México. Estos instrumentos se encuentran conectados al sistema de adquisición de datos de la RAMA por lo que existe una medición cada minuto. Los instrumentos fueron calibrados por el Servicio Solarimétrico Mexicano y referenciados a la Escala Radiométrica Mundial, garantizando que la calibración de las mediciones. Con la información solarimétrica de esta red, durante sus primeros cuatro años, se elaboraron mapas de Irradiación Solar Global en superficie, así como la Base de Datos correspondiente. Toda la información y los mapas, se encuentra disponible en la página de Internet del Servicio Solarimétrico Mexicano y puede ser consultada libremente (http://areas.geofisica.unam.mx/solarimetrico/). Este proyecto no tiene fecha para concluir, por lo que cada año se incrementará la base de datos y los mapas se volverán a elaborar anualmente para aumentar su certidumbre.ABSTRACT: In 2014, with funds of the Institute of Science and Technology of Mexico City (PINVII-7), 10 pyranometers were installed in stations from the Automatic Network of Atmospheric Monitoring (RAMA), of the Secretariat of the Environment of México City. These instruments are connected to the data acquisition system of the RAMA, sampled every minute. The instruments were calibrated by the Mexican Solarimetric Service and referenced to the Global Radiometric Scale, so the information generated is considered reliable. With the first four years information of this network, Global Solar Irradiation maps were prepared on the surface, as well as the corresponding Data Base. All information and maps are available on the website of the Solarimetric Mexican Service http://areas.geofisica.unam.mx/solarimetrico/ and can be consulted freely. This project does not have an ending date, so the database will be increased each year and the maps will be re-prepared annually to increase their certainty.info:eu-repo/semantics/publishedVersio

    Dating of the hominid (Homo neanderthalensis) remains accumulation from El Sidrón Cave (Piloña, Asturias, North Spain): an example of a multi-methodological approach to the dating of Upper Pleistocene sites.

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    The age of Neanderthal remains and associated sediments from El Sidrón cave has been obtained through different dating methods (14CAMS, U/TH, OSL, ESR and AAR) and samples (charcoal debris, bone, tooth dentine, stalagmitic flowstone, carbonate-rich sediments, sedi- mentary quartz grains, tooth enamel and land snail shells). Detrital Th contamination ren- dered Th/U dating analyses of flowstone unreliable. Recent 14C contamination produced spurious age-values from charcoal samples as well as from inadequately pretreated tooth samples. Most consistent 14C dates are grouped into two series: one between 35 and 40 ka and the other between 48 and 49 ka. Most ESR and AAR samples yielded concordant ages, ranging between 39 and 45 ka; OSL dating results permitted adequate bracketing of the sedimentary layer that contained the human remains. Our results emphasize the value of multi-dating approaches for the establishment of reliable chronologies of human remains

    Dating of the hominid (homo neanderthalensis) remains accumulation from el sidrón cave (piloña, asturias, north spain): An example of a multi-methodological approach to the dating of upper pleistocene sites

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    The age of Neanderthal remains and associated sediments from El Sidrón cave has been obtained through different dating methods (14CAMS, U/TH, OSL, ESR and AAR) and samples (charcoal debris, bone, tooth dentine, stalagmitic flowstone, carbonate-rich sedi

    High Antipredatory Efficiency of Insular Lizards: A Warning Signal of Excessive Specimen Collection?

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    We live-captured lizards on islands in the Gulf of California and the Baja California peninsula mainland, and compared their ability to escape predation. Contrary to expectations, endemic lizard species from uninhabited islands fled from humans earlier and more efficiently than those from peninsular mainland areas. In fact, 58.2% (n = 146) of the lizards we tried to capture on the various islands escaped successfully, while this percentage was only 14.4% (n = 160) on the peninsular mainland. Separate evidence (e.g., proportion of regenerated tails, low human population at the collection areas, etc.) challenges several potential explanations for the higher antipredatory efficiency of insular lizards (e.g., more predation pressure on islands, habituation to humans on the peninsula, etc.). Instead, we suggest that the ability of insular lizards to avoid predators may be related to harvesting by humans, perhaps due to the value of endemic species as rare taxonomic entities. If this hypothesis is correct, predation-related behavioral changes in rare species could provide early warning signals of their over-exploitation, thus encouraging the adoption of conservation measures

    On the chronological structure of the solutrean in Southern Iberia

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    The Solutrean techno-complex has gained particular significance over time for representing a clear demographic and techno-typological deviation from the developments occurred during the course of the Upper Paleolithic in Western Europe. Some of Solutrean's most relevant features are the diversity and techno-typological characteristics of the lithic armatures. These have been recurrently used as pivotal elements in numerous Solutrean-related debates, including the chronological organization of the techno-complex across Iberia and Southwestern France. In Southern Iberia, patterns of presence and/or absence of specific point types in stratified sequences tend to validate the classical ordering of the techno-complex into Lower, Middle and Upper phases, although some evidence, namely radiocarbon determinations, have not always been corroborative. Here we present the first comprehensive analysis of the currently available radiocarbon data for the Solutrean in Southern Iberia. We use a Bayesian statistical approach from 13 stratified sequences to compare the duration, and the start and end moments of each classic Solutrean phase across sites. We conclude that, based on the current data, the traditional organization of the Solutrean cannot be unquestionably confirmed for Southern Iberia, calling into doubt the status of the classically defined type-fossils as precise temporal markers.Fundacao para a Ciencia e Tecnologia [PTDC/HAH/64184/2006, PTDC/HIS-ARQ/117540/2010, SFRH/BD/65527/2009, SFRH/BPD/96277/2013]; National Geographic Society [8045-06]; Wenner-Gren Foundation for Anthropological Research [8290
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