Boundary integral methods in high frequency scattering

In this article we review recent progress on the design, analysis and implementation of numerical-asymptotic boundary integral methods for the computation of frequency-domain acoustic scattering in a homogeneous unbounded medium by a bounded obstacle. The main aim of the methods is to allow computation of scattering at arbitrarily high frequency with finite computational resources

An integral equation method for a boundary value problem arising in unsteady water wave problems

In this paper we consider the 2D Dirichlet boundary value problem for Laplace’s equation in a non-locally perturbed half-plane, with data in the space of bounded and continuous functions. We show uniqueness of solution, using standard Phragmen-Lindelof arguments. The main result is to propose a boundary integral equation formulation, to prove equivalence with the boundary value problem, and to show that the integral equation is well posed by applying a recent partial generalisation of the Fredholm alternative in Arens et al [J. Int. Equ. Appl. 15 (2003) pp. 1-35]. This then leads to an existence proof for the boundary value problem. Keywords. Boundary integral equation method, Water waves, Laplace’

Folgen der Europäischen Arbeitsmarkt- und Beschäftigungspolitik für demokratische Geschlechterverhältnisse

Mit dem Amsterdamer Vertrag wurde die supranationale Arbeitsmarkt- und Beschäftigungspolitik konsolidiert und mit der europäischen Geschlechterpolitik zusammengeführt. Erstmalig stellt das neu eingeführte Beschäftigungskapitel einen Zusammenhang zwischen Gleichstellungs- und Antidiskriminierungsrecht sowie Maßnahmen zur Integration von Frauen in die nationalen Arbeitsmärkte her. Neben der Chancengleichheit als eine vertraglich festgelegte Norm und dem Gender Mainstreaming-Programm gilt die Methode der offenen Koordinierung (OMK) als ein weiteres wichtiges Instrument zur Umsetzung der europäischen Zielvorgaben und Leitlinien. Ausgehend von der Frage, ob und inwiefern die europäische Arbeitsmarkt- und Beschäftigungspolitik tatsächlich als ein weiterer Meilenstein auf dem Weg zu demokratischen Geschlechterverhältnissen betrachtet werden kann, wird in einem ersten Schritt ein Überblick über die Entwicklung des Politikfeldes gegeben. In einem weiteren Schritt werden die Effekte der europäischen Arbeitsmarkt -und Beschäftigungspolitik auf gesellschaftliche Geschlechterverhältnisse skizziert. In diesem Zusammenhang wird gezeigt, dass die Verschränkung der EU-Gleichstellungspolitik mit der europäischen Beschäftigungsstrategie die Wirksamkeit des Antidiskriminierungsrechts schwächt und zu einer marktgerechten Erneuerung ungleicher Geschlechterverhältnisse in den nationalen Mitgliedstaaten führt<br

Positronium collisions with rare-gas atoms

We calculate elastic scattering of positronium (Ps) by the Xe atom using the recently developed pseudopotential method [I. I. Fabrikant and G. F. Gribakin, Phys. Rev. A 90, 052717 (2014)] and review general features of Ps scattering from heavier rare-gas atoms: Ar, Kr, and Xe. The total scattering cross section is dominated by two contributions: elastic scattering and Ps ionization (breakup). To calculate the Ps ionization cross sections we use the binary-encounter method for Ps collisions with an atomic target. Our results for the ionization cross section agree well with previous calculations carried out in the impulse approximation. Our total Ps-Xe cross section, when plotted as a function of the projectile velocity, exhibits similarity with the electron-Xe cross section for the collision velocities higher than 0.8 a.u., and agrees very well with the measurements at Ps velocities above 0.5 a.u.Comment: 7 pages, 7 figures, submitted to J. Phys.

Virtual Data in CMS Analysis

The use of virtual data for enhancing the collaboration between large groups of scientists is explored in several ways: - by defining ``virtual'' parameter spaces which can be searched and shared in an organized way by a collaboration of scientists in the course of their analysis; - by providing a mechanism to log the provenance of results and the ability to trace them back to the various stages in the analysis of real or simulated data; - by creating ``check points'' in the course of an analysis to permit collaborators to explore their own analysis branches by refining selections, improving the signal to background ratio, varying the estimation of parameters, etc.; - by facilitating the audit of an analysis and the reproduction of its results by a different group, or in a peer review context. We describe a prototype for the analysis of data from the CMS experiment based on the virtual data system Chimera and the object-oriented data analysis framework ROOT. The Chimera system is used to chain together several steps in the analysis process including the Monte Carlo generation of data, the simulation of detector response, the reconstruction of physics objects and their subsequent analysis, histogramming and visualization using the ROOT framework.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 9 pages, LaTeX, 7 eps figures. PSN TUAT010. V2 - references adde

Major tectonic units of the North China Craton and their Paleoproterozoic assembly

The basement of the North China Craton can be divided into the Eastern and Western Blocks and the Central Zone (Trans-North China Orogen). The West Block formed by the amalgamation of the Ordos Block in the south and the Yinshan Block in the north 1.9-2.0 Ga ago. In 1.8-1.9 Ga, the Eastern and Western Blocks were amalgamated along the Central Zone to form the North China Craton.published_or_final_versio

Die tunesische Verfassung zwischen demokratischem Anspruch und Verfassungsrealität

Die einstige Euphorie auf eine Demokratisierung der Staaten des „Arabischen Frühlings“ ist nach den jüngsten Entwicklungen in Libyen oder Ägypten getrübt. Einzig Tunesien gilt nach wie vor als hoffnungsvoller Kandidat für eine erfolgreiche demokratische Konsolidierung. Verstärkt wird dieser Enthusiasmus durch die Verabschiedung der neuen Verfassung im Januar 2014, die erstmals und einzigartig im arabischen Kontext, Menschen-, Freiheits- und Grundrechte gewährt, sowie die Gleichstellung der Geschlechter sichert. Fraglich ist jedoch, ob die Ratifizierung einer –zumindest formal betrachtet – demokratischen Verfassung auch zur Entwicklung einer demokratischen politischen Gesellschaft führt, die für die Beseitigung autoritärer und hybrider Strukturen notwendig ist. Um also Aussagen zum demokratischen Potential der tunesischen Verfassung machen zu können, müssen sowohl die Verfassungsrealität als auch ihre gesellschaftlichen und politischen Bedingungen hinterfragt werden

Observational Characterization of the Downward Atmospheric Longwave Radiation at the Surface in the City of São Paulo

This work describes the seasonal and diurnal variations of downward longwave atmospheric irradiance (LW) at the surface in São Paulo, Brazil, using 5-min-averaged values of LW, air temperature, relative humidity, and solar radiation observed continuously and simultaneously from 1997 to 2006 on a micrometeorological platform, located at the top of a 4-story building. An objective procedure, including 2-step filtering and dome emission effect correction, was used to evaluate the quality of the 9-yr-long LW dataset. The comparison between LW values observed and yielded by the Surface Radiation Budget project shows spatial and temporal agreement, indicating that monthly and annual average values of LW observed in one point of São Paulo can be used as representative of the entire metropolitan region of São Paulo. The maximum monthly averaged value of the LW is observed during summer (389 ± 14 W m-2; January), and the minimum is observed during winter (332 ± 12 W m-2; July). The effective emissivity follows the LW and shows a maximum in summer (0.907 ± 0.032; January) and a minimum in winter (0.818 ± 0.029; June). The mean cloud effect, identified objectively by comparing the monthly averaged values of the LW during clear-sky days and all-sky conditions, intensified the monthly average LW by about 32.0 ± 3.5 W m-2 and the atmospheric effective emissivity by about 0.088 ± 0.024. In August, the driest month of the year in São Paulo, the diurnal evolution of the LW shows a minimum (325 ± 11 W m-2) at 0900 LT and a maximum (345 ± 12 W m-2) at 1800 LT, which lags behind (by 4 h) the maximum diurnal variation of the screen temperature. The diurnal evolution of effective emissivity shows a minimum (0.781 ± 0.027) during daytime and a maximum (0.842 ± 0.030) during nighttime. The diurnal evolution of all-sky condition and clear-sky day differences in the effective emissivity remain relatively constant (7% ± 1%), indicating that clouds do not change the emissivity diurnal pattern. The relationship between effective emissivity and screen air temperature and between effective emissivity and water vapor is complex. During the night, when the planetary boundary layer is shallower, the effective emissivity can be estimated by screen parameters. During the day, the relationship between effective emissivity and screen parameters varies from place to place and depends on the planetary boundary layer process. Because the empirical expressions do not contain enough information about the diurnal variation of the vertical stratification of air temperature and moisture in São Paulo, they are likely to fail in reproducing the diurnal variation of the surface emissivity. The most accurate way to estimate the LW for clear-sky conditions in São Paulo is to use an expression derived from a purely empirical approach

Novel electrocardiographic criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy

Aims: In order to improve the electrocardiographic (ECG) diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC), we evaluated novel quantitative parameters of the QRS complex and the value of bipolar chest leads (CF leads) computed from the standard 12 leads. Methods and results: We analysed digital 12-lead ECGs in 44 patients with ARVC, 276 healthy subjects including 44 age and sex-matched with the patients and 36 genotyped members of ARVC families. The length and area of the terminal S wave in V1 to V3 were measured automatically using a common for all 12 leads QRS end. T wave negativity was assessed in V1 to V6 and in the bipolar CF leads computed from the standard 12 leads. The length and area of the terminal S wave were significantly shorter, whereas the S wave duration was significantly longer in ARVC patients compared with matched controls. Among members of ARVC families, those with mutations (n = 15) had shorter QRS length in V2 and V3 and smaller QRS area in lead V2 compared with those without mutations (n = 20). In ARVC patients, the CF leads were diagnostically superior to the standard unipolar precordial leads. Terminal S wave duration in V1 &gt;48 ms or major T wave negativity in CF leads separated ARVC patients from matched controls with 90% sensitivity and 86% specificity. Conclusion: The terminal S wave length and area in the right precordial leads are diagnostically useful and suitable for automatic analysis in ARVC. The CF leads are diagnostically superior to the unipolar precordial leads