Signatures of spin-preserving symmetries in two-dimensional hole gases

We investigate ramifications of the persistent spin helix symmetry in two-dimensional hole gases in the conductance of disordered mesoscopic systems. To this end we extend previous models by going beyond the axial approximation for III-V semiconductors. For heavy-hole subbands we identify an exact spin-preserving symmetry analogous to the electronic case by analyzing the crossover from weak antilocalization to weak localization and spin transmission as a function of extrinsic spin-orbit interaction strength.Comment: 7 pages, 3 figures; reference adde

Whole-field 3D Characterization of a Pulsating Jet using Synthetic Aperture Particle Image Velocimety

In this study synthetic aperture particle image velocimetry is used on an excised human vocal fold model to study the airflow over the vocal folds during voice production. For the first time, a whole-field, time-resolved, 3D description of the flow is presented over one cycle of vocal fold oscillation. Complex, unsteady, 3D flow behavior is observed as the jet evolves

Directed Evolution of Gloeobacter violaceus Rhodopsin Spectral Properties

Proton-pumping rhodopsins (PPRs) are photoactive retinal-binding proteins that transport ions across biological membranes in response to light. These proteins are interesting for light-harvesting applications in bioenergy production, in optogenetics applications in neuroscience, and as fluorescent sensors of membrane potential. Little is known, however, about how the protein sequence determines the considerable variation in spectral properties of PPRs from different biological niches or how to engineer these properties in a given PPR. Here we report a comprehensive study of amino acid substitutions in the retinal binding pocket of Gloeobacter violacaeus rhodopsin (GR) that tune its spectral properties. Directed evolution generated 70 GR variants with absorption maxima shifted by up to +/- 80 nm, extending the protein’s light absorption significantly beyond the range of known natural PPRs. While proton pumping activity was disrupted in many of the spectrally shifted variants, we identified single tuning mutations that incurrred blue and red shifts of 42 nm and 22 nm, respectively, that did not disrupt proton pumping. Blue-shifting mutations were distributed evenly along the retinal molecule while red-shifting mutations were clustered near the residue K257, which forms a covalent bond with retinal through a Schiff base linkage. Thirty-four of the identified tuning mutations are not found in known microbial rhodopsins. We discovered a subset of red-shifted GRs that exhibit high levels of fluorescence relative to the wild-type protein

An accurate test for homogeneity of odds ratios based on Cochran's Q-statistic

Background: A frequently used statistic for testing homogeneity in a meta-analysis of K independent studies is Cochran's Q. For a standard test of homogeneity the Q statistic is referred to a chi-square distribution with K - 1 degrees of freedom. For the situation in which the effects of the studies are logarithms of odds ratios, the chi-square distribution is much too conservative for moderate size studies, although it may be asymptotically correct as the individual studies become large. Methods: Using a mixture of theoretical results and simulations, we provide formulas to estimate the shape and scale parameters of a gamma distribution to t the distribution of Q. Results: Simulation studies show that the gamma distribution is a good approximation to the distribution for Q. Conclusions: : Use of the gamma distribution instead of the chi-square distribution for Q should eliminate inaccurate inferences in assessing homogeneity in a meta-analysis. (A computer program for implementing this test is provided.) This hypothesis test is competitive with the Breslow-Day test both in accuracy of level and in power

Similar complication rates for irreversible electroporation and thermal ablation in patients with hepatocellular tumors

Background. To compare the frequency of adverse events of thermal microwave (MWA) and radiofrequency ablation (RFA) with non-thermal irreversible electroporation (IRE) in percutaneous ablation of hepatocellular carcinoma (HCC). Patients and methods. We retrospectively analyzed 117 MWA/RFA and 47 IRE procedures (one tumor treated per procedure; 144 men and 20 women; median age, 66 years) regarding adverse events, duration of hospital and intensive care unit (ICU) stays and occurrence of a post-ablation syndrome. Complications were classified according to the Clavien & Dindo classification system. Results. 70.1% of the RFA/MWA and 63.8% of the IRE procedures were performed without complications. Grade I and II complications (any deviation from the normal postinterventional course, e.g., analgesics) occurred in 26.5% (31/117) of MWA/RFA and 34.0% (16/47) of IRE procedures. Grade III and IV (major) complications occurred in 2.6% (3/117) of MWA/RFA and 2.1% (1/47) of IRE procedures. There was no significant difference in the frequency of complications (p = 0.864), duration of hospital and ICU stay and the occurrence of a post-ablation syndrome between the two groups. Conclusions. Our results suggest that thermal (MWA and RFA) and non-thermal IRE ablation of malignant liver tumors have comparable complication rates despite the higher number of punctures and the lack of track cauterization in IRE

Focus: Implementing participation - Advancement of social services in analog and digital spaces

Digitale Informations- und Kommunikationstechnologien gewinnen als fester Bestandteil zunehmend Bedeutung in den alltäglichen Lebenswelten einer wachsenden Zahl von Menschen. Ihre Entwicklung und selbstverständliche Nutzung schreiten in einem immer rasanteren Tempo voran; die vielfältigen Anwendungsmöglichkeiten adressieren längst alle Lebensbereiche. Während der Digitalisierung von Kommunikationsprozessen zuweilen demokratisierende Kräfte zugesprochen werden, scheint eine kritische Reflexion möglicher Potentiale und Auswirkungen digitaler Informations- und Kommunikationstechnologien auf Teilhabedynamiken in unterschiedlichen Lebensbereichen dringend erforderlich. Die Autorinnen und Autoren möchten mit dieser SI:SO-Schwerpunktausgabe einen Beitrag zu einer kritischen Reflexion digitaler Innovationen und ihrer Auswirkungen auf die zukünftige Gestaltung sozialer Dienste leisten. Mit der zweisprachigen Ausgabe ist zudem die Hoffnung verbunden, diesen Beitrag auch einem europäischen und weltweiten Publikum zugänglich zu machen.Digital information and communications technologies are becoming an increasingly important part in everyday life of a growing number of people. Their development and natural use are progressing even faster with a wide range of possible applications addressing all areas of life. While the digitization of communication processes is sometimes said to have democratizing forces, critical reflection on the potential and impact of digital information and communication technologies on participation dynamics in different areas of life seems urgently needed. The Authors would like to contribute to a critical reflection on digital innovations and their impact on the future design of social services. The bilingual edition further aims to make this contribution accessible to a European and global audience

Schwerpunkt: Rechtsextremismus und Soziale Arbeit

Das SI:SO-Heft widmet sich den folgenden Fragen: - Unter welchen Gesichtspunkten lassen sich Rechtspopulismus und Rechtsextremismus differenziert diskutieren? - Wie werden Rechtsextreme bestimmt und Rechtsextremismus identifiziert? - Inwiefern ist Soziale Arbeit von Rechtsextremismus und Rechtspopulismus betroffen? - Welche Kritiken gelten als zulässig, welche nicht und welche Auseinandersetzungen werden in der Sozialen Arbeit gemieden? - Welche politischen und zivilgesellschaftlichen Beiträge leistet Soziale Arbeit im Phänomenbereich Rechtsextremismus und Rechtspopulismus? - Welche Folgen ergeben sich für Hochschulen und Studium im Umgang mit Rechtsextremismus und Rechtspopulismus

The neutron and its role in cosmology and particle physics

Experiments with cold and ultracold neutrons have reached a level of precision such that problems far beyond the scale of the present Standard Model of particle physics become accessible to experimental investigation. Due to the close links between particle physics and cosmology, these studies also permit a deep look into the very first instances of our universe. First addressed in this article, both in theory and experiment, is the problem of baryogenesis ... The question how baryogenesis could have happened is open to experimental tests, and it turns out that this problem can be curbed by the very stringent limits on an electric dipole moment of the neutron, a quantity that also has deep implications for particle physics. Then we discuss the recent spectacular observation of neutron quantization in the earth's gravitational field and of resonance transitions between such gravitational energy states. These measurements, together with new evaluations of neutron scattering data, set new constraints on deviations from Newton's gravitational law at the picometer scale. Such deviations are predicted in modern theories with extra-dimensions that propose unification of the Planck scale with the scale of the Standard Model ... Another main topic is the weak-interaction parameters in various fields of physics and astrophysics that must all be derived from measured neutron decay data. Up to now, about 10 different neutron decay observables have been measured, much more than needed in the electroweak Standard Model. This allows various precise tests for new physics beyond the Standard Model, competing with or surpassing similar tests at high-energy. The review ends with a discussion of neutron and nuclear data required in the synthesis of the elements during the "first three minutes" and later on in stellar nucleosynthesis.Comment: 91 pages, 30 figures, accepted by Reviews of Modern Physic