Strong-field above-threshold photoemission from sharp metal tips

We present energy-resolved measurements of electron emission from sharp metal tips driven with low energy pulses from a few-cycle laser oscillator. We observe above-threshold photoemission with a photon order of up to 9. At a laser intensity of 2*10^11 W/cm^2 suppression of the lowest order peak occurs, indicating the onset of strong-field effects. We also observe peak shifting linearly with intensity with a slope of around -1.8eV / (10^12 W/cm^2). We attribute the magnitude of the laser field effects to field enhancement taking place at the tip's surface.Comment: 5 pages, 3 figure

16 years of Ulysses Interstellar Dust Measurements in the Solar System: II. Fluctuations in the Dust Flow from the Data

The Ulysses spacecraft provided the first opportunity to identify and study Interstellar Dust (ISD) in-situ in the Solar System between 1992 and 2007. Here we present the first comprehensive analysis of the ISD component in the entire Ulysses dust data set. We analysed several parameters of the ISD flow in a time-resolved fashion: flux, flow direction, mass index, and flow width. The general picture is in agreement with a time-dependent focussing/defocussing of the charged dust particles due to long-term variations of the solar magnetic field throughout a solar magnetic cycle of 22 years. In addition, we confirm a shift in dust direction of $50^{\circ} \pm 7^{\circ}$ in 2005, along with a steep, size-dependent increase in flux by a factor of 4 within 8 months. To date, this is difficult to interpret and has to be examined in more detail by new dynamical simulations. This work is part of a series of three papers. This paper concentrates on the time-dependent flux and direction of the ISD. In a companion paper (Kr\"uger et al., 2015) we analyse the overall mass distribution of the ISD measured by Ulysses, and a third paper discusses the results of modelling the flow of the ISD as seen by Ulysses (Sterken et al., 2015).Comment: 41 pages, 10 figures, 5 table

Coarse-grained Second Order Response Theory

While linear response theory, manifested by the fluctuation dissipation theorem, can be applied at any level of coarse graining, nonlinear response theory is fundamentally of microscopic nature. For perturbations of equilibrium systems, we develop an exact theoretical framework for analyzing the nonlinear (second order) response of coarse grained observables to time-dependent perturbations, using a path-integral formalism. The resulting expressions involve correlations of the observable with coarse grained path weights. The time symmetric part of these weights depends on the paths and perturbation protocol in a complex manner; in addition, the absence of Markovianity prevents slicing of the coarse-grained path integral. We show that these difficulties can be overcome and the response function can be expressed in terms of path weights corresponding to a single-step perturbation. This formalism thus leads to an extrapolation scheme where measuring linear responses of coarse-grained variables suffices to determine their second order response. We illustrate the validity of the formalism with an exactly solvable four-state model and the near-critical Ising model.Comment: 12 pages, 7 figure

Feature modeling: An extended perspective to design IT infrastructure

Feature modeling is a widely used method in systems engineering. Feature models help to communicate the requirements and architecture of IT systems. Applying feature models to IT infrastructure is a rare explored field in system development. We advocate using feature modeling for designing IT infrastructure to give an additional perspective on systems architecture and implement functions and properties of IT infrastructure. In this research-inprogress paper we present the idea of combining feature modeling and IT infrastructures and propose an exemplified feature model in context of IT infrastructure and its corresponding research questions. The discussion leads to functional and non-functional-requirements, feature-oriented description of architecture, and scope of IT infrastructure

Gruppenspezifität der Generalprävention - was aus einer Erhöhung der Promillegrenze zu lernen ist

No abstract availabl

Alkohol: Konsum, Wirkung, Gefahren für die Verkehrssicherheit. Zur Diskussion um neue Grenzwerte

Im ersten Teil werden die Ergebnisse einer umfangreichen Literaturstudie zu Auswirkungen niedriger Alkoholkonzentrationen auf die Fahrsicherheit vorgestellt. Es wird gezeigt, daß bei Konzentration über 0.6 Promille die Leistungsausfälle drastisch ansteigen, dies umso mehr, je mehr es sich um komplexe Handlungen handelt und je näher der Zeitpunkt der Leistungsabgabe dem Trinkende liegt. Diese Ergebnisse decken sich mit Studien aus Verkehrsunfällen, bei denen ebenfalls über 0.7 Promille ein explosionsartiges Ansteigen des Risikos gezeigt wurde. Demgegenüber ist ein deutlich erhöhtes Risiko für den Bereich unter 0.5 Promille nicht nachgewiesen. An Untersuchungen zum Alkoholkonsum wird aufgezeigt, daß die Alkoholtrinker in mehrere Subpopulationen aufzuteilen sind. Dabei wird insbesondere eine Gruppe von Konsumtrinkern identifiziert, deren BAK regelhaft 0.6/0.7 Promille nicht überschreitet. Es wird gezeigt, daß diese Gruppe wahrscheinlich nicht überproportional zu ihrem Auftreten an Unfällen beteiligt ist. Daraus wird die Forderung nach der Einführung eines einzigen, strafrechtlich bewehrten Grenzwerts abgeleitet, der bei etwa 0.7/0.8 Promille liegen sollte.In the first section we present the results of an extensive review of the sciemific Iiterature on the effects of low dosages of alcohol on driving performance. We show that when BAC exceeds a limit of about 0.06 %, the impairment of performance becomes drastically increasing as the complexity of the tasks increases and as the elapsed time between drinking and measurement decreases (resorption phase). These results agree with those coming from accident research, which show a sharp increase of accident risk when BAC exceeds a limit of about 0.07 %. On the other hand, at concentrations below 0.05 %, a significantly higher risk as compared to sober conditions has not been proved up to now. Studies on alcohol consumption Iead one to distinguish between different subgroups of consumers. A !arge group of 'normal consumers' is idemified whose BAC regularily remains below 0.06/0.07 %. It is shown that this group is probably not overrepresemed in accidents. We deduce from these facts that the extstmg German BAC limits should be replaced with a single Iegallimit of about 0.07/0.08 %

Effects of low alcohol dosages: A review of the literature

No abstract available

Nähe und Distanz in sozialen Beziehungen und ihre quantitative Erfassung

Es wird ein neues soziometrisches Verfahren vorgeschlagen, das in seiner Grundlegung von heute üblichen Wahlverfahren abweicht. Dabei wird versucht, in einem ersten Teil die Gedanken darzustellen, die zur Formulierung der soziometrischen Fragen geführt haben. Im zweiten Teil wird der Gang der Auswertung dargestellt, der ein differenziertes Bild der untersuchten Personen zeichnen soll. Im Teil "Ergebnisse" wird am Beispiel von Extremgruppen gezeigt, was die Methode leisten kann. Schließlich werden noch mögliche Modifikationen des Verfahrens aufgezeigt