1,055 research outputs found

    Medical Support and Findings of the Skylab Program

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    Specific equipment used in carrying out Skylab medical experiments is outlined and illustrated. Also included are reviews of the techniques, frequency, and protocols of the tests designed to study the long term effects of weightlessness on the human body. In-flight investigations were an evaluation of the cardiovascular system, a study of metabolic activity, investigations in the field of neurophysiology, the determination of changes in body fluids, a precise measurement of total body metabolism, and a study of crew performance by use of a time and motion experiment. Significant data obtained from in-flight and postflight tests are outlined

    Working Memory and Disinhibition In Children with ADHD

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    This research sought to test predictions from Barkley\u27s (1997) theory of disinhibition in Attention Deficit Hyperactivity Disorder (ADHD). To this end, the performance differences among younger and older children with and without ADHD were measured. The testing paradigm used in this study was originally developed by Hale, Bronik, and Fry (1997), who sought to measure the verbal and spatial working memory differences in school age children. In this study, ADHD children performed significantly worse on the tasks than did non-ADHD children, indicating that the working memory of the children with ADHD was more subject to interference. Also, younger children performed significantly worse on the tasks than did older children. Finally, older ADHD children performed worse than younger non-ADHD children within testing paradigm. These results provide some support for Barkley\u27s theory of disinhibition

    Spectral properties of localized continuum random Schrödinger operators

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    The results presented in this thesis are mainly motivated by the attempt to improve the mathematical understanding of the localized spectral region of random quantum mechanical systems. It is common wisdom in theoretical (and experimental) physics that a variety of spectral properties are characteristic indicators for the presence of spectral localization. The mathematical verifi of such characteristic properties at large is one of the key concerns of the theory of random Schrödinger operators. The first topic we address, based on joint work with Martin Gebert and Peter MĂŒller [37], is a phenomenon dubbed Anderson orthogonality : Given two non-interacting, quasi-free electron systems which only differ by a local perturbation, Anderson orthogonality refers to the vanishing of their ground-state overlap in the macroscopic limit. We prove that in the localized spectral region Anderson orthogonality and absence of Anderson orthogonality both typically appear with positive probability. As a consequence, the disorder-averaged ground- state overlap does not vanish in the macroscopic limit. Combined with the mathematical results from [51], this shows that the absence of Anderson orthogonality can indeed be viewed as a characteristic property of the localized spectral region. Another test for the spectral structure of a random quantum mechanical system is its local eigenvalue statistics. On the one hand, it is common sense in physics that the eigenvalue statistics for a generic localized system are poissonian. But, on the other hand, previously known proofs only applied for the lattice Anderson model and similar lattice models. Irre- spective of the concrete model, a mandatory requirement to obtain Poisson statistics of the local eigenvalue process around a reference energy E is a positive density of states at that point. As a first step towards Poisson statistics we prove, based on joint work with Martin Gebert, Peter Hislop, Abel Klein and Peter MĂŒller [37], a strictly positive lower bound on the density of states for continuum random Schrödinger operators. Then, based on joint work with Alexander Elgart [36], we present a new proof for poissonian local eigenvalue statistics. It is more flexible than known methods and, for instance, applicable to continuum random Schrödinger operators. A phenomenon reminiscent of the vanishing of the ground-state overlap described above is the logarithmic enhancement of asymptotic SzegƑ-type trace formulas. The absence of a logarithmic enhancement for the localized lattice Anderson model is already known [100, 43]. But motivated by those works, we prove [35] a full asymptotic expansion for the trace of h(g(Hω )[−L,L]d ) in terms of the length-scale L, where h and g are suitable functions and Hω is a general ergodic operator. Our key assumption here is that the operator kernel of g(Hω ) exhibits sufficient spatial decay, which can be verifi either under a spectral localization assumption on Hω or a regularity assumption on g.Die Resultate, die ich im Rahmen meiner Dissertation vorstelle, sind hauptsĂ€chlich motiviert durch das Bestreben, das mathematische VerstĂ€ndnis des lokalisierten Spektralbereichs zufĂ€lliger quantenmechanischer Systeme zu verbessern. In der theoretischen (und experimentellen) Physik gelten verschiedene Spektraleigenschaften als charakteristische Indikatoren fĂŒr das Vorliegen einer lokalisierten spektralen Phase. Das mathematische BestĂ€tigen solcher Charakteristika in möglichst großer Allgemeinheit ist eines der Kernthemen der Theorie zufĂ€l- liger Schrödingeroperatoren. Im ersten Projekt dieser Dissertation, welches auf einer Zusammenarbeit mit Martin Gebert und Peter MĂŒller basiert [37], wird die sogenannte Anderson OrthogonalitĂ€t unter- sucht: Gegeben seien zwei nicht wechselwirkende Elektronensysteme, deren Einteilchenoperatoren sich nur um eine lokale Störung unterscheiden. Dann spricht man von Anderson OrthogonalitĂ€t, falls der Überlapp der beiden GrundzustĂ€nde der Elektronensysteme im makroskop- ischen Limes gegen null strebt. Wir zeigen, dass Anderson OthogonalitĂ€t sowie deren Ab- wesenheit im lokalisierten Spektralbereich eines zufĂ€lligen Schrödingeroperators beide mit positiver Wahrscheinlichkeit auftreten. Folglich verschwindet der zufallsgemittelte GrundzustandsĂŒberlapp nicht im makroskopischen Limes. In Kombination mit bereits bekannten Resultaten [51] zeigt dies, dass das Verhalten des GrundzustandĂŒberlapps im makroskopischen Limes ein Indikator eines lokalisierten Spektralbereichs ist. Ein weiterer Test fĂŒr die Spektralstruktur eines zufĂ€lligen quantenmechanischen Systems ist dessen lokale Eigenwertstatistik. Es ist Teil der Folklore der Physik, dass eine poisson- verteilte lokale Eigenwertstatistik ein universeller Indikator eines lokalisierten Systems ist. Andererseits funktionieren bekannte Beweise nur fĂŒr das klassiche Andersonmodell und Ă€hnliche Modelle auf dem Gitter. UnabhĂ€ngig vom jeweiligen Modell ist eine notwendige Bedingung fĂŒr eine poissonverteilte lokale Eigenwertstatistik bei der Referenzenergie E die strikte PositivitĂ€t der Zustandsdichte an dieser Energie. Im zweiten Projekt, welches auf einer Zusammenarbeit mit Martin Gebert, Peter Hislop, Abel Klein und Peter MĂŒller basiert [37], wird eine strikt positive untere Schranke an die Zustandsdichte von zufĂ€lligen Schrödingeroperatoren im Kontinuum etabliert. Danach prĂ€sentiere ich, basierend auf Resultaten die in Zusammenarbeit mit Alexander Elgart entstanden [36], einen neuen Beweis fĂŒr die poissonsche lokale Eigenwert- statistik. Dieser ist deutlich flexibler als bekannte Beweise und ist zum Beispiel anwendbar auf zufĂ€llige Schrödingeroperatoren im Kontinuum. Ein PhĂ€nomen, welches dem oben beschriebenen asymptotischen Verschwinden des GrundzustandsĂŒberlapps Ă€hnlich ist, ist die logarithmische VerstĂ€rkung der fĂŒhrenden Ord- nung sogenannter asymptotischer SzegƑ Spurformeln. Die Absenz solcher logarithmischer VerstĂ€rkungen fĂŒr lokalisierte zufĂ€llige Schrödingeroperatoren ist bereits bekannt [100, 43]. Auf- bauend auf diesen Arbeiten beweise ich [35] eine komplette asymptotische Entwicklung fĂŒr die Spur des Operators h(g(Hω )[−L,L]d ) in der LĂ€ngenskala L, wo h und g geeignete Funktionen sind und Hω ein allgemeiner ergodischer Operator. Die Hauptannahme, unter der diese komplette asymptotische Entwicklung gĂŒltig ist, ist hinreichend schneller Abfall des Operatorkerns des Operators g(Hω ). Eine solche Annahme kann nachgewiesen werden unter entweder einer spektralen Lokalisierungsannahme fĂŒr den Operator Hω oder einer RegularitĂ€tsannahme fĂŒr die Funktion g

    Evaluation of phonocardiographic data of astronauts during orbital flights

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    Simultaneous electrocardiographic and phonocardiographic data obtained from Gemini flight

    The development of refugee law clinics in Germany in view of the refugee crisis in Europe

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    Coming to an unknown country, seeking for refuge, having nobody anymore, because of the family murdered by a criminal regime, not being able to speak the language of the country, having no idea of the legal system – this scenario can put refugees in very difficult circumstances, especially if the refugees need legal advice concerning their situation. There is not only the pressure of getting along with the horrific experiences the refugee went through but sometimes even legal problems that have to be solved, sometimes problems that may decide whether a person can stay in the country or has to leave it.And most of the time small issues, like how to deal with certain formalities or what steps to undertake next, are in question. This is where law clinics, especially the specialized refugee law clinics, might help
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