Spin noise spectroscopy in GaAs (110) quantum wells: Access to intrinsic spin lifetimes and equilibrium electron dynamics

In this letter, the first spin noise spectroscopy measurements in semiconductor systems of reduced effective dimensionality are reported. The non-demolition measurement technique gives access to the otherwise concealed intrinsic, low temperature electron spin relaxation time of n-doped GaAs (110) quantum wells and to the corresponding low temperature anisotropic spin relaxation. The Brownian motion of the electrons within the spin noise probe laser spot becomes manifest in a modification of the spin noise line width. Thereby, the spatially resolved observation of the stochastic spin polarization uniquely allows to study electron dynamics at equilibrium conditions with a vanishing total momentum of the electron system

Controlling hole spin dynamics in two‐dimensional hole systems at low temperatures

With the recent discovery of very long hole spin decoherence times in GaAs/AlGaAs heterostructures of more than 70 ns in two-dimensional hole systems, using the hole spin as a viable alternative to electron spins in spintronic applications seems possible. Furthermore, as the hyperfine interaction with the nuclear spins is likely to be the limiting factor for electron spin lifetimes in zero dimensions, holes with their suppressed Fermi contact hyperfine interaction due to their p-like nature should be able to show even longer lifetimes than electrons. For spintronic applications, electric-field control of hole spin dynamics is desirable. Here, we report on time-resolved Kerr rotation and resonant spin amplification measurements on a two-dimensional hole system in a p-doped GaAs/AlGaAs heterostructure. Via a semitransparent gate, we tune the charge density within the sample. We are able to observe a change in the hole g factor, as well as in the hole spin dephasing time at high magnetic fields

Resonant spin amplification of hole spin dynamics in two‐dimensional hole systems: experiment and simulation

Spins in semiconductor structures may allow for the realization of scalable quantum bit arrays, an essential component for quantum computation schemes. Specifically, hole spins may be more suited for this purpose than electron spins, due to their strongly reduced interaction with lattice nuclei, which limits spin coherence for electrons in quantum dots. Here, we present resonant spin amplification (RSA) measurements, performed on a p-modulation doped GaAs-based quantum well at temperatures below 500 mK. The RSA traces have a peculiar, butterfly-like shape, which stems from the initialization of a resident hole spin polarization by optical orientation. The combined dynamics of the optically oriented electron and hole spins are well-described by a rate equation model, and by comparison of experiment and model, hole spin dephasing times of more than 70 ns are extracted from the measured data

Examining Collaboration in Interdisciplinary Product Development Focusing on Dependencies

Product development in manufacturing industry is characterized by intense collaboration need of various stakeholders. Increasing integration of disciplines in modern products makes it more and more a challenge to arrange collaboration efficiently and effectively. Process and product characteristics as well as the architecture of information systems used in product development have to be considered. This paper introduces a methodology for the design of collaboration situations based on principles of system analysis. First, a collaboration situation is defined and modelled regarding constituent elements in the domains process, product and system. Second, a description model for dependencies in these domains is developed. Morphological analysis was applied to derive features and characteristics of the model. Third, an improvement approach to optimize a given collaboration situation is depicted. The improvement approach comprises a sensitivity model, which explicates causal relations between the dependency features. The methodology is applied to a case study from manufacturing industry

News From The Gamma Cephei Planetary System

The Gamma Cephei planetary system is one of the most interesting systems due to several reasons: 1.) it is the first planet candidate detected by precise radial velocity (RV) measurements that was discussed in the literature (Campbell et al. 1988); 2.) it is a tight binary system with a ~ 20AU; and 3.) the planet host star is an evolved K-type star. In Hatzes et al. (2003) we confirmed the presence of the planetary companion with a minimum mass of 1.7 M_Jup at 2 AU. In this paper we present additional eight years of precise RV data from the Harlan J. Smith 2.7 m Telescope and its Tull Coude spectrograph at McDonald Observatory. The 900 d signal, that is interpreted as the presence of the giant planetary companion, is strongly confirmed by adding the new data. We present an updated orbital solution for the planet, which shows that the planet is slightly more massive and the orbit more circular than previous results have suggested. An intensive high-cadence week of RV observations in 2007 revealed that Gamma Cep A is a multi-periodic pulsator. We discuss this issue within the context of searching for additional planets in this system.Comment: Part of PlanetsbeyondMS/2010 proceedings http://arxiv.org/html/1011.660

Die ambulante arthroskopisch-assistierte Rekonstruktion des vorderen Kreuzbandes mit einem freien Patellarsehnentransplantat

In die vorliegende retrospektive Untersuchung wurden 102 Kreuzbandverletzungen aus den Jahren 1995 und 1996 einbezogen, die in einer vorwiegend arthroskopisch tätigen Praxisklinik ambulant operativ versorgt wurden. Erhoben wurden neben persönlichen Daten und der subjektiven Zustandsbeurteilung des Kniegelenkes durch verschiedene Auswertungsbögen (Lysholm-Score, Tegner-Aktivitätsscore, IKDC-Score) die Ergebnisse einer klinischen, radiologischen sowie muskelfunktions-diagnostischen Nachuntersuchung. Anhand der Untersuchungsergebnisse, im Durchschnitt 2 Jahre postoperativ, konnte gezeigt werden, dass mit der ambulant durchgeführten vorderen Kreuzbandplastik im Vergleich zu den Ergebnissen der vorhandenen Literatur für ein stationäres Vorgehen mindestens gleich gute Ergebnisse erzielt werden. Ein primär akutes/subakutes Vorgehen innerhalb von 6 Wochen nach Verletzung zeigt in der Untersuchung tendenziell bessere Ergebnisse, auch hinsichtlich der nachfolgenden Dauer der Arbeitsunfähigkeit, jedoch ohne eindeutige Signifikanz. Weiterhin zeigen sich in der Untersuchung keine signifikanten Unterschiede zwischen einer einzeitigen bzw. mehrzeitigen operativen Versorgung, bei der die Kreuzbandplastik im Intervall erfolgt. Die eigene ermittelte Komplikationsrate von 14,7%, die eine Rearthroskopie notwendig machten, darf nicht unterschätzt werden. Die Indikation zur vorderen Kreuzbandplastik sollte somit trotz aller Fortschritte in Diagnostik, Therapie und Nachbehandlung weiterhin gründlich geprüft werden

Prevalência de factores de risco de desnutrição em pacientes hospitalizados na América Latina: uma análise nutritionDay 2016-2020

Hospital malnutrition is a complex international health issue described to be associated with worse patient outcomes and increased healthcare costs(1). A large proportion of patients is already found malnourished at the time of hospital admission, others develop malnutrition while in hospital, often as a complication associated with the disease. Malnutrition screening is crucial for identifying vulnerable patients who are nutritionally at risk already on admission, presenting well-known risk factors such as poor appetite, low food intake, history of unintentional weight loss or low body mass index (BMI).La desnutrición hospitalaria es un problema de salud complejo a nivel internacional, el cual, según se ha descrito, se asocia con peores desenlaces para los pacientes y costos más elevados para los sistemas de salud(1). Es grande la proporción de pacientes que llegan desnutridos al momento de su ingreso al hospital; otros desarrollan desnutrición durante su estancia hospitalaria como una complicación asociada con su patología. El tamizaje para desnutrición es crucial para identificar a aquellos pacientes con riesgo nutricional al momento de su ingreso, y los factores de riesgo bien conocidos son la falta de apetito, baja ingesta de alimento, historia de pérdida de peso no intencional o bajo índice de masa corporal (IMC)