303 research outputs found
Differences into HT and HTO concentrations in air into the Western Mediterranean Basin and Continental Europe and Safety Related Issues.
Real time Tritium concentrations in air in two chemical forms, HT and HTO, coming from an ITER-like fusion reactor as source were coupled the European Centre Medium Range Weather Forecast (ECMWF) numerical model with the Lagrangian Atmospheric-particle dispersion model FLEXPART. This tool was analyzed in nominal tritium discharge operational reference and selected incidental conditions affecting the Western Mediterranean Basin during 45 days during summer 2010 together with surface “wind observations” or weather data based in real hourly observations of wind direction and velocity providing a real approximation of the tritium behavior after the release to the atmosphere from a fusion reactor. From comparison with NORMTRI - a code using climatologically sequences as input - over the same area, the real time results have demonstrated an apparent overestimation of the corresponding climatologically sequence of Tritium concentrations in air outputs, at several distances from the reactor. For this purpose two development patterns were established. The first one was following a cyclonic circulation over the Mediterranean Sea and the second one was based on the plume delivered over the Interior of the Iberian Peninsula and Continental Europe by another stabilized circulation corresponding to a High Pressure System. One of the important remaining activities defined then, was the qualification tool. In order to validate the model of ECMWF/FLEXPART we have developed of a new complete data base of tritium concentrations for the months from November 2010 to March 2011 and defined a new set of four patterns of HT transport in air, in each case using real boundary conditions: stationary to the North, stationary to the South, fast and very fast displacement. Finally the differences corresponding to those four early patterns (each one in assessments 1 and 2) has been analyzed in terms of the tuning of safety related issues and taking into account the primary phase o- - f tritium modeling, from its discharge to the atmosphere to the deposition on the ground, will affect to the complete tritium environmental pathway altering the chronic dose by absorption, reemission and ingestion both from elemental tritium, HT and from the oxide of tritium, HT
COVID-19 desde la perspectiva de la prevención primaria: Perspective on the Primary Prevention of COVID-19
This article seeks to describe the main primary prevention measures on the 2019-nCoV or COVID-19 that is recently affecting our country, considering epidemiological aspects and recommendations applied and reported in other countries. The topics covered are the prevention of traveling patients, the importance of hand hygiene, respiratory prevention, policies in educational centers and prevention for health personnel. This is due to the need for a better characterization of this new health problem in our country, to establish public policies based on the prevention of complications from this new virus, taking into account assessments based on scientific, preventive and social evidence.El presente artículo busca describir las principales medidas de prevención primaria sobre el 2019-nCoV o COVID-19 que recientemente está afectando a nuestro país, considerando aspectos epidemiológicos y recomendaciones aplicadas y reportadas en otros países. Los temas abordados son la prevención de los pacientes viajeros, la importancia de la higiene de manos, prevención por vía respiratoria, políticas en centros educacionales y prevención para el personal de salud. Ello obedece a la necesidad de una mejor caracterización de este nuevo problema de salud en nuestro país, para establecer políticas públicas en base a la prevención de las complicaciones de este nuevo virus, teniendo en cuenta las valoraciones basadas en evidencia científica, preventiva y social
A U-shaped protection of altitude against mortality and infection of COVID-19 in Peru: An ecological study
Background The COVID-19 pandemic has affected the world in multiple ways and has been a challenge for the
health systems of each country. From the beginning, risk factors for the severity and mortality of the disease were
considered, as the spread of the virus was related to the living conditions of each population.
Methods In this ecological study we have evaluated the role of geography, precisely the altitude above sea level
in the incidence and mortality of COVID-19 in Peru. Incidence and mortality data were taken from the open-access
database of the government of Peru until March 2021. COVID-19 cases and COVID-19 mortality were treated as
cases/density population and 1000 x cases/inhabitants while altitude was treated as continuous and as a categorical
variable divided in 7 categories. The relationship between COVID-19 cases or deaths for COVID-19 and altitude as
continuous variable was determined using Spearman correlation test. Meanwhile when altitude was considered as a
categorical variable, Poisson regression or negative binomial analyses were applied.
Results A significant inverse correlation was found between COVID-19 cases by population density and altitude
(r=-0.37 p < 0.001). By altitude categories, the lowest risk for infection was observed between 3,000 and 3,500 m (IRR
0.08; 95% CI 0.05,0.12). Moreover, we found an inverse correlation between altitude and COVID-19 mortality (r=-0.39
p < 0.001). Also, the lowest risk for mortality was observed between 3,000 and 3,500 m (IRR 0.12; 95%CI 0.08; 0.18).
Similar results were found when analyses were adjusted for inhabitants and stratified by sex.
Conclusion This study reports an inverse relationship between COVID-19 incidence and mortality with respect to the
altitude of residence, particularly, a u-shaped protection is shown, with a highest benefit between 3000 and 3500 m.
The possibility of using hypoxia as an alternative treatment requires more complex studies that should allow knowing
the physiological and environmental mechanisms of the protective role
Atmospheric modelling of Tritium forms transport: review of capabilities and R&D needs for the assessment of fusion facilities environmental impact
Comunicación presentada en: 38ª Reunión Anual de la Sociedad Nuclear Española celebrada del 17 al 19 de octubre de 2012 en Cáceres.This work models in detail the dispersion of tritium forms and dosimetric impact of selected environmental patterns both inland and in-sea using real topography and forecast meteorological data-fields (ECMWF/FLEXPART). We explore specific values of this ratio in different levels and we examine the influence of meteorological conditions in the HTO behavior for 24 hours. For this purpose we have used a tool which consists on a coupled Lagrangian ECMWF/FLEXPART model useful to follow real time releases of tritium at 10, 30 and 60 meters together with hourly observations of wind (and in some cases precipitations) to provide a short-range approximation of tritium cloud behavior. We have assessed inhalation doses. And also HTO/HT ratios in a representative set of cases during winter 2010 and spring 2011 for the 3 air levels
Influence of particle density on flow behavior and deposit architecture of concentrated pyroclastic density currents over a break in slope: Insights from laboratory experiments
Geological granular flows are highly complex, gravity-driven phenomena whose different behaviors depend on the mechanical properties, density and granulometric distributions of the constituent materials. Years of research have produced significant advances in understanding transport and deposition processes in granular flows. However, the role and effects of clast densities and density contrast in a granular flow are still not fully understood. In this paper we show the effect that pumice has on dry granular flows; specifically on flow velocity and longitudinal segregation of the deposits. Our work confirms, by experimental results, field observations on pumice/lithic segregation and longer pumice runout. We report results of velocity decay and deposit architecture for a granular flow passing over a break in slope (from 38° to 4° inclination). The 30 experimental runs were carried out in a five-meter long laboratory flume equipped with a series of sensors that include laser gates and high-speed cameras (400 fps). We used two polydisperse mixtures of dacitic lithics and rhyolitic pumice in varying amounts, with Weibull and Gaussian particle size distributions. The pumice/lithic ratio changes the flow response passing over a break in slope. This effect is particularly evident starting from 10% of pumice volume into the flow mixture, independently of its granulometric distribution. Runout relates to mass following a power law, with an exponent close 0.2. The experiments confirm that pumice segregation affects polydispersed mixtures, similarly to what has been observed in real field deposits, where density decoupling produces lithic-enriched proximal areas and pumice-enriched distal areas. The results obtained prove that the presence of low-density materials in a dense granular flow has a strong influence on its behavior
Rational General Solutions of Systems of Autonomous Ordinary Differential Equations of Algebro-Geometric Dimension One
The final journal version of this paper appears in A. Lastra, J. R. Sendra, L. X. C. Ngô and F. Winkler\ud
(2014). Rational General Solutions of Systems of Autonomous Ordinary Differential Equations of Algebro-\ud
Geometric Dimension One. Publ. Math. Debrecen Publ. Math. Debrecen 2015 / 86 / 1-2 49–69. DOI:\ud
10.5486/PMD.2015.6032 and it is available at http://dx.doi.org/10.5486/PMD.2015.6032An algebro-geometric method for determining the rational solvability\ud
of autonomous algebraic ordinary differential equations is extended from single equations\ud
of order 1 to systems of equations of arbitrary order but dimension 1 in the algebrogeometric\ud
sense. We provide necessary conditions, for the existence of rational solutions,\ud
on the degree and on the structure at infinity of the associated algebraic curve. Furthermore,\ud
from a rational parametrization of a planar projection of the corresponding\ud
space curve one deduces, either by derivation or by lifting the planar parametrization,\ud
the existence and actual computation of all rational solutions if they exist. Moreover, if\ud
the differential polynomials are defined over the rational numbers, we can express the\ud
rational solutions over the same field of coefficients.Vietnam Institute for Advanced Study in Mathematics (VIASM
Validation of real time dispersion of Tritium clouds over the Western Mediterranean Basin in different assesments
Real time Tritium concentrations in air coming from an ITER-like reactor as source were coupled the European Centre Medium Range Weather Forecast (ECMWF) numerical model with the lagrangian atmospheric dispersion model FLEXPART. This tool ECMWF/FLEXPART was analyzed in normal operating conditions in the Western Mediterranean Basin during 45 days at summer 2010. From comparison with NORMTRI plumes over Western Mediterranean Basin the real time results have demonstrated an overestimation of the corresponding climatologically sequence Tritium concentrations in air outputs, at several distances from the reactor. For these purpose two clouds development patterns were established. The first one was following a cyclonic circulation over the Mediterranean Sea and the second one was based in the cloud delivered over the Interior of the Iberian Peninsula by another stabilized circulation corresponding to a High. One of the important remaining activities defined then, was the tool qualification. The aim of this paper is to present the ECMWF/FLEXPART products confronted with Tritium concentration in air data. For this purpose a database to develop and validate ECMWF/FLEXPART tritium in both assessments has been selected from a NORMTRI run. Similarities and differences, underestimation and overestimation with NORMTRI will allowfor refinement in some features of ECMWF/FLEXPAR
High genetic connectivity in a gastropod with long-lived planktonic larvae
Genetic connectivity plays a crucial role in shaping the geographic structure of species. Our aim in this study was to explore the pattern of genetic connectivity in Bursa scrobilator, an iconic marine caenogastropod with long-lived pelagic larvae. Our study was based on the analysis of DNA sequence data for the 658-bp barcoding fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene. This is the largest DNA sequence dataset assembled to date for B. scrobilator. These data confirm that the two recently described subspecies B. scrobilator scrobilator (Linnaeus, 1758), from the Mediterranean and Macaronesia, and B. s. coriacea (Reeve, 1844), from West Africa, constitute two evolutionarily significant units (ESUs). We found that for the nominal subspecies, the variation in morphology (shell, radula and gross anatomy) and DNA sequences was not geographically structured, and this agrees with what we would expect in a species with high connectivity at the larval stage. The divergence between the two subspecies cannot be easily explained by isolation by distance, and we would argue that one or more extrinsic factors may have played a role in isolating the two ESUs and maintaining that isolation
Ocorrência de Isogonoceraia divergipennis White & Hodkinson (1980) associado a Caesalpinia pluviosa (Fabaceae) em Mato Grosso, Brasil.
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