5,783 research outputs found

    A New Spinning-test Method

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    This report contains a description of a new spinning-test arrangement wherein the otherwise customary rotation of the model about a fixed axis is abandoned in favor of a corresponding rotation of the air stream. The advantage of this method lies in the fact that the model is at rest while the spin is recorded. In this manner it is possible to secure systematic results with little loss of time while employing 3- or 6-component wind-tunnel balances. The troublesome equalization of the mass forces is eliminated and the flow phenomena are accessible to direct observation

    The Focke Helicopter

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    This report presents some of the problems concerning tests of helicopters, such as forced landings, controllability and stability, general safety, piloting maneuvers, performance, servicing, and the production of lift of a propeller. Test flights are described including a 67.67 mph flight by Hanna Reitsch

    The effects of lifestyle and diet on gut microbiota composition, inflammation and muscle performance in our aging society

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    Living longer is associated with an increased risk of chronic diseases, including impairments of the musculoskeletal and immune system as well as metabolic disorders and certain cancers, each of which can negatively affect the relationship between host and microbiota up to the occurrence of dysbiosis. On the other hand, lifestyle factors, including regular physical exercise and a healthy diet, can affect skeletal muscle and immune aging positively at all ages. Accordingly, health benefits could partly depend on the effect of such interventions that influence the biodiversity and functionality of intestinal microbiota. In the present review, we first discuss the physiological effects of aging on the gut microbiota, immune system, and skeletal muscle. Secondly, we describe human epidemiological evidence about the associations between physical activity and fitness and the gut microbiota composition in older adults. The third part highlights the relevance and restorative mechanisms of immune protection through physical activity and specific exercise interventions during aging. Fourth, we present important research findings on the effects of exercise and protein as well as other nutrients on skeletal muscle performance in older adults. Finally, we provide nutritional recommendations to prevent malnutrition and support healthy active aging with a focus on gut microbiota. Key nutrition‐related concerns include the need for adequate energy and protein intake for preventing low muscle mass and a higher demand for specific nutrients (e.g., dietary fiber, polyphenols and polyunsaturated fatty acids) that can modify the composition, diversity, and metabolic capacity of the gut microbiota, and may thus provide a practical means of enhancing gut and systemic immune function

    Many-body nodal hypersurface and domain averages for correlated wave functions

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    We outline the basic notions of nodal hypersurface and domain averages for antisymmetric wave functions. We illustrate their properties and analyze the results for a few electron explicitly solvable cases and discuss possible further developments

    Model Independent Analysis of the Forward-Backward Asymmetry for the B→K1ÎŒ+Ό−B\to K_{1}\mu^{+}\mu^{-} Decay

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    The sensitivity of the zero position of the forward backward asymmetry AFB\mathcal{A}_{FB} for the exclusive B→K1(1270)ÎŒ+Ό−B\rightarrow K_{1}(1270)\mu^{+}\mu^{-} decay is examined by using most general non-standard 4-fermion interactions. Our analysis shows that the zero position of the forward backward asymmetry is very sensitive to the sign and size of the Wilson coefficients corresponding to the new vector type interactions, which are the counter partners of the usual Standard Model operators but have opposite chirality. In addition to these, the other significant effect comes from the interference of Scalar-Pseudoscalar and Tensor type operators. These results will not only enhance our theoretical understanding about the axial vector mesons but will also serve as a good tool to look for physics beyond the SM.Comment: 14 pages, 8 figures, Published version that appears in EPJ

    Social Media and its Impact on Therapeutic Relationships

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    In the current age of social media, the boundaries between the online and the offline, the personal and the professional, have become blurred and ambiguous. This poses significant challenges to the practice of psychoanalysis, which for a long time has been thought of as a technology‐free and private space. This paper compares how social media impacts therapeutic relationships in the broader field of psychotherapy and in psychoanalytic psychotherapy in particular. Direct breaches in therapist privacy were found to be more frequent with non‐psychoanalytic psychotherapists due to therapists’ higher online presence. Psychoanalytic psychotherapists, on the other hand, generally have a lesser online presence because of different views on therapeutic anonymity from other clinical orientations. The author suggests that this leads to different forms of virtual impingements: due to the absence of psychoanalytic therapists’ online presence, patients seek to re‐create therapists (and, by extension, therapeutic situations) on a virtual level rather than discover something that was already ‘put out there’ by therapists. Virtual manifestations of anonymity, splitting, and solipsistic introjection processes are discussed with reference to John Suler's concept of the online disinhibition effect. Further recommendations for research on social media impact are discussed

    Decay of isolated surface features driven by the Gibbs-Thomson effect in analytic model and simulation

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    A theory based on the thermodynamic Gibbs-Thomson relation is presented which provides the framework for understanding the time evolution of isolated nanoscale features (i.e., islands and pits) on surfaces. Two limiting cases are predicted, in which either diffusion or interface transfer is the limiting process. These cases correspond to similar regimes considered in previous works addressing the Ostwald ripening of ensembles of features. A third possible limiting case is noted for the special geometry of "stacked" islands. In these limiting cases, isolated features are predicted to decay in size with a power law scaling in time: A is proportional to (t0-t)^n, where A is the area of the feature, t0 is the time at which the feature disappears, and n=2/3 or 1. The constant of proportionality is related to parameters describing both the kinetic and equilibrium properties of the surface. A continuous time Monte Carlo simulation is used to test the application of this theory to generic surfaces with atomic scale features. A new method is described to obtain macroscopic kinetic parameters describing interfaces in such simulations. Simulation and analytic theory are compared directly, using measurements of the simulation to determine the constants of the analytic theory. Agreement between the two is very good over a range of surface parameters, suggesting that the analytic theory properly captures the necessary physics. It is anticipated that the simulation will be useful in modeling complex surface geometries often seen in experiments on physical surfaces, for which application of the analytic model is not straightforward.Comment: RevTeX (with .bbl file), 25 pages, 7 figures from 9 Postscript files embedded using epsf. Submitted to Phys. Rev. B A few minor changes made on 9/24/9
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