312 research outputs found

    Improving efficiency and robustness of enhanced assumed strain elements for nonlinear problems

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    The enhanced assumed strain (EAS) method is one of the most frequently used methods to avoid locking in solid and structural finite elements. One issue of EAS elements in the context of geometrically nonlinear analyses is their lack of robustness in the Newton–Raphson scheme, which is characterized by the necessity of small load increments and large number of iterations. In the present work we extend the recently proposed mixed integration point (MIP) method to EAS elements in order to overcome this drawback in numerous applications. Furthermore, the MIP method is generalized to generic material models, which makes this simple method easily applicable for a broad class of problems. In the numerical simulations in this work, we compare standard strain‐based EAS elements and their MIP improved versions to elements based on the assumed stress method in order to explain when and why the MIP method allows to improve robustness. A further novelty in the present work is an inverse stress‐strain relation for a Neo‐Hookean material model

    Evaluation der Maßnahmen zur Umsetzung der VorschlĂ€ge der Hartz-Kommission: Arbeitspaket 2, Organisatorischer Umbau der Bundesagentur fĂŒr Arbeit ; Bericht 2005

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    "Die Bundesagentur fĂŒr Arbeit steht im Jahr 2005 inmitten der Implementation des umfassendsten organisatorischen Umbaus ihrer Geschichte. Nach der Konzeptionsphase im Jahr 2003 und der Erprobung in 2004 soll die Umsetzung der BA-Reform in 2005 weitgehend abgeschlossen werden. Zum gegenwĂ€rtigen Zeitpunkt lĂ€sst sich folgende vorlĂ€ufige Bilanz ziehen: Der Umbau der Gesamtorganisation mit der Zentrale, zustĂ€ndig fĂŒr Zielsetzung und Strategieentwicklung, den Regionaldirektionen, zustĂ€ndig fĂŒr die Steuerung der Agenturen und den Agenturen, zustĂ€ndig fĂŒr das operative GeschĂ€ft, ist weit fortgeschritten und kann als ein gelungenes Element des Reformprozesses betrachtet werden. Die verschlankte Zentrale der BA ist nun wohl zum ersten Male in ihrer Geschichte steuerungsfĂ€hig gegenĂŒber ihren nachgeordneten Ebenen und kann durch das FĂŒhrungssystem die Umsetzung ihrer Vorgaben in den Agenturen auf der Grundlage von Controllingdaten systematisch nachhalten. Die EinfĂŒhrung der neuen Steuerungslogik nach Wirkung und Wirtschaftlichkeit und die Entwicklung einer echten Zielsteuerung stellen eine ebenfalls anzuerkennende Leistung dar. Festzuhalten ist allerdings, dass trotz erklĂ€rtem Willen zur Dezentralisierung in der Praxis der Zielsteuerung die Regionaldirektionen gegenĂŒber den Agenturen eine dominierende Rolle gewonnen haben, so dass nur von einer halbierten Dezentralisierung gesprochen werden kann. (...)" (Textauszug

    Evaluation der Maßnahmen zur Umsetzung der VorschlĂ€ge der Hartz-Kommission: Arbeitspaket 2, Organisatorischer Umbau der Bundesagentur fĂŒr Arbeit ; Evaluationsbericht 2006

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    "Der im Jahre 2002 begonnene organisatorische Umbau der Bundesagentur fĂŒr Arbeit wird nach der FlĂ€cheneinfĂŒhrung des Kundenzentrums in den Agenturen im Jahre 2005 in diesem Jahr weitgehend abgeschlossen werden. Die hier vorgelegten Untersuchungsergebnisse resultieren aus einer begleitenden Untersuchung des Umbaus von Oktober 2004 bis Juni 2006. Die wesentlichen Befunde lassen sich (in AuszĂŒgen) wie folgt zusammenfassen: Die Reform verlief aufgrund einer professionellen und stringenten Umsetzungssteuerung mit einem strikten Top-Down-Verfahren weitgehend reibungslos. ... Im Rahmen der Reform wurden die Organisationseinheiten der BA neu ausgerichtet: die Zentrale ist zustĂ€ndig fĂŒr Strategie und Zielsetzung, die Regionaldirektionen steuern die Agenturen, die als unternehmerische Filialen das operative GeschĂ€ft verantworten. Ein ĂŒbergreifendes Ziel der neuen Steuerung ist die Ausrichtung der BA an Wirkung und Wirtschaftlichkeit. Ausgaben zur Wiedereingliederung in den Arbeitsmarkt sollen zu einem betriebswirtschaftlichen Nettoeffekt fĂŒhren. Produkte sollen so eingesetzt werden, dass die Gesamtdauer der Arbeitslosigkeit verkĂŒrzt wird und deren Wirkung mit hoher Wahrscheinlichkeit vor Übertritt in den SGB II-Rechtskreis erfolgt. Das zentrale geschĂ€ftspolitische Ziel der BA ist eine Maximierung der Integrationszahlen. Dieser Indikator hĂ€ngt in hohem Maße von externen Faktoren ab und ist fĂŒr die Beurteilung der LeistungsfĂ€higkeit der BA nur begrenzt aussagekrĂ€ftig. Das komplexe Controllingsystem bietet eine Datengrundlage fĂŒr die monatliche Nachhaltung der Zielvereinbarungen, welche die Zentrale mit den Regionaldirektionen und diese wiederum mit den Agenturen schließen. Zugleich fĂŒhrt diese zahlengetriebene Steuerung zu einer Überdeterminierung der operativen Prozesse in den Agenturen, mit zum Teil erheblichen Transaktionskosten." (Textauszug

    Antideuterons as a Signature of Supersymmetric Dark Matter

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    Once the energy spectrum of the secondary component is well understood, measurements of the antiproton cosmic-ray flux at the Earth will be a powerful way to indirectly probe for the existence of supersymmetric relics in the galactic halo. Unfortunately, it is still spoilt by considerable theoretical uncertainties. As shown in this work, searches for low-energy antideuterons appear in the mean time as a plausible alternative, worth being explored. Above a few GeV/n, a dozen spallation antideuterons should be collected by the future AMS experiment on board ISSA. For energies less than about 3 GeV/n, the antideuteron spallation component becomes negligible and may be supplanted by a potential supersymmetric signal. If a few low-energy antideuterons are discovered, this should be seriously taken as a clue for the existence of massive neutralinos in the Milky Way.Comment: 16 pages, 9 figure

    Food allergy in EAACI journals (2016).

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    The European Academy of Allergy and Clinical Immunology (EAACI) owns three journals: Allergy, Pediatric Allergy and Immunology and Clinical and Translational Allergy. One of the major goals of EAACI is to understand and better manage food allergy, and to disseminate the knowledge of allergy to all stakeholders including the EAACI junior members (1). The European Symposium on Precision Medicine in Allergy and Airways Diseases at the European Union Parliament (October 14, 2015) stressed that the socioeconomic impact of food allergy (2). This article is protected by copyright. All rights reserved

    Honey is potentially effective in the treatment of atopic dermatitis: Clinical and mechanistic studies

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    Introduction: As manuka honey (MH) exhibits immunoregulatory and anti-staphylococcal activities, we aimed to investigate if it could be effective in the treatment of atopic dermatitis (AD). Methods: Adult volunteers with bilateral AD lesions were asked to apply MH on one site overnight for 7 consecutive days and leave the contralateral site untreated as possible. Three Item Severity score was used to evaluate the response. Skin swabs were obtained from both sites before and after treatment to investigate the presence of staphylococci and enterotoxin production. In addition, the ability of MH and its methanolic and hexane extracts to down regulate IL4-induced CCL26 protein release from HaCaT cells was evaluated by enzyme linked immunosorbent assay. Also, the ability of MH to modulate calcium ionophore-induced mast cell degranulation was assessed by enzyme immunoassay. Results: In 14 patients, AD lesions significantly improved post MH treatment vs. pre-treatment as compared to control lesions. No significant changes in the skin staphylococci were observed after day 7, irrespective of honey treatment. Consistent with the clinical observation, MH significantly down regulated IL4-induced CCL26 release from HaCaT cells in a dose dependent manner. This effect was partially lost, though remained significant, when methanolic and hexane extracts of MH were utilized. In addition, mast cell degranulation was significantly inhibited following treatment with MH. Conclusions: MH is potentially effective in the treatment of AD lesions based on both clinical and cellular studies through different mechanisms. This needs to be confirmed by randomized and controlled clinical trials.

    Faddeev Calculations of Proton-Deuteron Radiative Capture with Exchange Currents

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    pd capture processes at various energies have been analyzed based on solutions of 3N-Faddeev equations and using modern NN forces. The application of the Siegert theorem is compared to the explicit use of π\pi- and ρ\rho-like exchange currents connected to the AV18 NN interaction. Overall good agreement with cross sections and spin observables has been obtained but leaving room for improvement in some cases. Feasibility studies for 3NF's consistently included in the 3N continuum and the 3N bound state have been performed as well.Comment: Minor changes in notation, ps files for figure

    Observations of the December 13 and 14, 2006, Solar Particle Events in the 80 MeV/n - 3 GeV/n range from space with PAMELA detector

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    We present the space spectrometer PAMELA observations of proton and helium fluxes during the December 13 and 14, 2006 solar particle events. This is the first direct measurement of the solar energetic particles in space with a single instrument in the energy range from ∌\sim 80 MeV/n up to ∌\sim 3 GeV/n. In the event of December 13 measured energy spectra of solar protons and helium were compared with results obtained by neutron monitors and other detectors. Our measurements show a spectral behaviour different from those derived from the neutron monitor network. No satisfactory analytical fitting was found for the energy spectra. During the first hours of the December 13 event solar energetic particles spectra were close to the exponential form demonstrating rather significant temporal evolution. Solar He with energy up to ~1 GeV/n was recorded on December 13. In the event of December 14 energy of solar protons reached ~600 MeV whereas maximum energy of He was below 100 MeV/n. The spectra were slightly bended in the lower energy range and preserved their form during the second event. Difference in the particle flux appearance and temporal evolution in these two events may argue for a special conditions leading to acceleration of solar particles up to relativistic energies.Comment: Accepted for publication on Astrophysical journa

    Further investigation of a relic neutralino as a possible origin of an annual-modulation effect in WIMP direct search

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    We analyze the annual-modulation effect, measured by the DAMA Collaboration with the new implementation of a further two-years running, in the context of a possible interpretation in terms of relic neutralinos. We impose over the set of supersymmetric configurations, selected by the annual-modulation data, the constraints derived from WIMP indirect measurements, and discuss the features of the ensuing relic neutralinos. We critically discuss the sources of the main theoretical uncertainties in the analysis of event rates for direct and indirect WIMP searches.Comment: 29 pages, 12 figures, typeset with ReVTeX. In order to reduce size, the version on the archive has low resolution figures. A full version of the paper can be found at http://www.to.infn.it/~fornengo/papers
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