The severe thunderstorm of 4 October 2007 in Mallorca: an observational study

During the afternoon of 4 October 2007, a thunderstorm swept across the Island of Mallorca from southwest to northeast. Strong straight-line winds (up to 30 m/s) and heavy rain (rates up to 100 mm/h) were registered accompanying the storm. Tornadoes with an estimated intensity of F2–F3 developed nearby the city of Palma, severely affecting industrial installations. One person was killed by the impact of heavy debris while more than 10 million € in damages were attributed to the event in the industrial area only. The observed evolution of temperature, humidity, wind and pressure, as well as the sequence of radar images, reveal that a squall line was initially organized over the sea and then moved north-eastwards at an estimated speed of around 80 km/h. This paper presents an analysis of the event from an observational point of view. The aim of the study is to contribute to the characterization of these rare events in the Western Mediterranean by analyzing the observational information available for this particular extreme event. The diagnosis is aimed at helping forecasters to identify this kind of organized deep convective events and being able to issue timely warnings. The synoptic scenario shows warm and moist advection at low levels over Balearics and an upper-level trough over mainland Spain. This situation is known to be prone to deep convection in Mediterranean Spain in autumn. Radiosonde ascents from Murcia and Palma show convective instability at mid levels that can conduce to develop convection if appropriate ascents occur. A plausible lifting mechanism to trigger convection is attributed to large amplitude gravity waves, registered as short-period pressure oscillations by surface barographs

On collisional free-free photon absorption in warm dense matter

The rate of photon absorption in warm dense matter (WDM) induced by free-free electron-ion collisions is derived from Sommerfeld's cross-section for non-relativistic bremsstrahlung emission, making use of detailed balance relations. Warm dense matter is treated as a metal-like state in the approximation of a uniform degenerate electron gas and a uniform ion background. Total absorption rates are averaged over the electron Fermi distribution. A closed expression is obtained for the absorption rate, depending on temperature, density, and photon energy, that scales with ion charge Z. It is evaluated numerically for the full parameter space, which requires different representations of the hypergeometric functions involved. The results are valid for photon frequencies larger than the plasma frequency of the medium. They are compared with approximate formulas in various asymptotic regions

Papel dos mass media electrónicos regionais na implementação dos projectos nacionais

The research deals with the role of mass media in solving the matters of inter-ethnic nature. It is emphasized that particularly the regional mass media effectively cope with this objective, being an authority among the mass audience and having impact on it. Activity of the electronic mass media in the Republic of Tatarstan is analyzed, where a decent media experience of solving inter-ethnic matters is accumulated. These are the largest TV companies in the region: "Tatarstan - Novy Vek", the potential audience of which is over 35 million viewers; "Tatarstan" State TV and Radio Company (Affiliate of FSUE RSTRBC STRBC "Tatarstan") (with the audience over four million people), as well as the portal of the Assembly and the House of Friendship of Nations of Tatarstan. The structural, meaningful analysis of the projects being implemented is carried out: the TV programs "Karavay" ("Tatarstan - Novy Vek"), "National Question and Answer" (STRBC "Tatarstan") are covered. The range of problems of the programs, the image characteristics of the materials' authors are focused on. Two major format-forming features are revealed: the story- type and information-news ones. In addition to the TV communications, the Internet resources are actively involved in covering the subject under study. It is established that one of the most significant platforms is the portal of the Assembly and the House of Friendship of Nations of Tatarstan, where a wide range of multimedia tools is deployed.La investigación trata sobre el papel de los medios de comunicación en la resolución de asuntos de naturaleza interétnica. Se enfatiza que particularmente los medios de comunicación regionales efectivamente hacen frente a este objetivo, siendo una autoridad entre la audiencia masiva y teniendo impacto en ella. Se analiza la actividad de los medios de comunicación electrónicos en la República de Tatarstán, donde se acumula una experiencia mediática decente para resolver cuestiones interétnicas. Estas son las compañías de televisión más grandes de la región: "Tatarstan - Novy Vek", cuya audiencia potencial es de más de 35 millones de televidentes; "Tatarstán", la Compañía Estatal de TV y Radio (Afiliada de FSUE RSTRBC STRBC "Tatarstan") (con una audiencia de más de cuatro millones de personas), así como el portal de la Asamblea y la Casa de la Amistad de las Naciones de Tatarstán. Se lleva a cabo el análisis estructural y significativo de los proyectos que se están implementando: los programas de televisión "Karavay" ("Tatarstán - Novy Vek"), "Pregunta y respuesta nacional" (STRBC "Tatarstán") están cubiertos. La gama de problemas de los programas se centra en las características de imagen de los autores de los materiales. Se revelan dos características principales de formación de formato: el tipo de historia y las noticias de información. Además de las comunicaciones de televisión, los recursos de Internet participan activamente en la cobertura del tema en estudio. Se establece que una de las plataformas más importantes es el portal de la Asamblea y la Casa de la Amistad de las Naciones de Tatarstán, donde se despliega una amplia gama de herramientas multimedia. A pesquisa trata do papel dos meios de comunicação de massa na solução dos assuntos de natureza interétnica. Ressalta-se que particularmente os meios de comunicação regionais lidam efetivamente com esse objetivo, sendo uma autoridade entre o público de massa e tendo impacto sobre ele. A atividade dos meios de comunicação eletrônicos na República do Tartaristão é analisada, onde uma experiência de mídia decente de resolução de questões interétnicas é acumulada. Estas são as maiores empresas de TV da região: "Tatarstan - Novy Vek", cuja audiência potencial é de mais de 35 milhões de telespectadores; "Tatarstan" TV estatal e companhia de rádio (afiliada de FSUE RSTRBC STRBC "Tatarstan") (com a audiência mais de quatro milhões de pessoas), bem como o portal da Assembleia e a Casa de Amizade das Nações do Tartaristão. A análise estrutural e significativa dos projetos que estão sendo implementados é realizada: os programas de TV "Karavay" ("Tatarstan - Novy Vek"), "Questões e Respostas Nacionais" (STRBC "Tatarstan") são abordados. A gama de problemas dos programas, as características da imagem dos autores dos materiais são focadas. Dois principais recursos formadores de formato são revelados: o tipo de história e os de informação-notícias. Além das comunicações de TV, os recursos da Internet estão ativamente envolvidos na cobertura do assunto em estudo. Estabelece-se que uma das plataformas mais significativas é o portal da Assembléia e a Casa da Amizade das Nações do Tartaristão, onde é implantada uma ampla gama de ferramentas multimídia

Numerical study of the October 2000 torrential precipitation event over eastern Spain: analysis of the synoptic-scale stationarity

International audienceA torrential precipitation event affected eastern Spain during 21 to 24 October 2000. Total accumulated rainfall higher than 500 mm was registered at some locations, with values up to 300 mm in a 24-h period. The synoptic-scale charts for these days show the presence of a cold cutoff low aloft, south of the Iberian Peninsula, as a part of an W-blocking structure over Europe. At low levels, persistent easterly winds, established between a dominant anticyclone over eastern Europe and a cyclone over Morocco, are found over the western Mediterranean throughout the entire period. Satellite images show the advance and breaking away of a trough, with an associated cold front, over the Iberian Peninsula, which resulted in the cutoff low formation. Later, scattered convective cells are detected along the eastern Spanish coast during more than 3 days. Numerical simulations reveal that the convective environment was developed by the low-level advection of warm and moist air from central Mediterranean, being charged of moisture by evaporation from the sea. Sensitivity runs confirm that the synoptic-scale persistent low-level easterly flow, and specifically, the presence of a low level jet, was crucial for the subsynoptic processes leading to the long lasting torrential rainfall over the exposed terrains of eastern Spain. The stagnancy of the low-level flow is attributed to the quasi-stationary characteristics of the upper level cutoff low located south of the Iberian Peninsula. Experiments with modified upper-level potential vorticity distributions reveal that slight deviations from the observed configuration result in enhanced mobility of the low-level flow pattern, and thereby a reduction of the precipitation persistence. This suggests the major importance of a correct representation in the model initial conditions of the intensity and location of the upper level features, in order to obtain valuable numerical forecasts of these heavy rainfall events

Implosion Symmetry of Laser-Irradiated Cylindrical Targets

We consider the symmetry of cylindrical implosions of laser targets with parameters corresponding to experiments proposed for the LIL laser facility at Bordeaux: eight laser beams in octahedrical configuration, delivering a total of 50 kJ of 0.35 (xm laser light in 5 ns, impinging on 1.26 mm diameter polystyrene cylindrical shells filled with deuterium at 30 bar and 5.35 mg cm"3; this configuration allows to place diagnostics along the symmetry axis to evaluate directly the uniformity of implosion. Numerical studies have been carried out by using the hydrodynamic computer codes MULTI and CHIC, including one-dimensional, and two-dimensional R-Z and R-6 simulations. Deuterium is compressed into a 1 mm long and 50 |xm diameter filament, with density ranging from 2 to 6 g cm-3 and temperatures above 1000 eV. In spite of the reduced numbers of beams, a good symmetry can be achieved with a careful choice of the irradiation pattern. The heat transport smoothing between laser absorption zone and ablation layer plays a fundamental role in the attenuation of residual non-uniformities. Also, it has been found that the radiation transport determines the radial structure of the compressed filament