5,692 research outputs found
Auswirkungen erhöhter sozialer UnterstĂŒtzung auf das Wohlbefinden kognitiv beeintrĂ€chtigter Ă€lterer Menschen
Zusammenfassung: Soziale Beziehungen stellen einen wichtigen Faktor fĂŒr den Erhalt der Lebenszufriedenheit im Alter dar. Wenig bekannt ist, welchen Einfluss erhöhte soziale UnterstĂŒtzung auf das Wohlbefinden kognitiv beeintrĂ€chtigter Menschen hat. In zwei vergleichenden Studien in der Schweiz und Ăsterreich mit insgesamt 84 kognitiv beeintrĂ€chtigten Personen (65-98Jahre) in stationĂ€rer Betreuung wurde deshalb in einem Kontrollgruppendesign untersucht, ob sich die Erhöhung sozialer UnterstĂŒtzung positiv auf das Wohlbefinden auswirkt. Dazu wurden Interventionen bei kognitiv beeintrĂ€chtigten Menschen in Form von emotionaler sozialer UnterstĂŒtzung durch freiwillige Besucher durchgefĂŒhrt. In beiden Studien konnte ein positiver Zusammenhang zwischen der Erhöhung sozialer UnterstĂŒtzung durch freiwillige Helfer und dem Wohlbefinden der Probanden festgestellt werden. Die Untersuchungen zeigen auf, dass soziale UnterstĂŒtzung und Zuwendung generell von kognitiv beeintrĂ€chtigten Menschen registriert und als wohltuend empfunden werde
Mechanisms altering airway smooth muscle cell Ca(2+) homeostasis in two asthma models
Background: Asthma is characterized by airway remodeling, altered mucus production and airway smooth muscle cell (ASMC) contraction causing extensive airway narrowing. In particular, alterations of ASMC contractility seem to be of crucial importance. The elevation of the cytoplasmic Ca(2+) concentration is a key event leading to ASMC contraction and changes in the agonist- induced Ca(2+) increase in ASMC have been reported in asthma. Objective: The aim of this study was to investigate mechanisms underlying these changes. Methods: Murine tracheal smooth muscle cells (MTSMC) from T- bet KO mice and human bronchial smooth muscle cells (HBSMC) incubated with IL-13 and IL-4 served as asthma models. Acetylcholine- induced changes in the cytoplasmic Ca(2+) concentration were recorded using fluorescence microscopy and the expression of Ca(2+) homeostasis regulating proteins was investigated with Western blot analysis. Results: Acetylcholine- induced Ca(2+) transients were elevated in both asthma models. This correlated with an increased Ca(2+) content of the sarcoplasmic reticulum (SR). In MTSMC from T-bet KO mice, the expression of the SR Ca(2+) buffers calreticulin and calsequestrin was higher compared to wild- type mice. In HBSMC incubated with IL-13 or IL-4, the expression of ryanodine receptors, inositol-3-phosphate receptors and sarcoplasmic/ endoplasmic reticulum Ca 2+ ATPases 2 was increased compared to HBSMC without incubation with interleukins. The enlarged acetylcholine- induced Ca(2+) transients could be reversed by blocking inositol-3- phosphate receptors. Conclusions: We conclude that in the murine asthma model the SR Ca(2+) buffer capacity is increased, while in the human asthma model the expression of SR Ca(2+) channels is altered. The investigation of the Ca(2+) homeostasis of ASMC has the potential to provide new therapeutical options in asthma. Copyright (C) 2008 S. Karger AG, Basel
Parameterization for subgrid-scale motion of ice-shelf calving fronts
A parameterization for the motion of ice-shelf fronts on a Cartesian grid in finite-difference land-ice models is presented. The scheme prevents artificial thinning of the ice shelf at its edge, which occurs due to the finite resolution of the model. The intuitive numerical implementation diminishes numerical dispersion at the ice front and enables the application of physical boundary conditions to improve the calculation of stress and velocity fields throughout the ice-sheet-shelf system. Numerical properties of this subgrid modification are assessed in the Potsdam Parallel Ice Sheet Model (PISM-PIK) for different geometries in one and two horizontal dimensions and are verified against an analytical solution in a flow-line setup
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Parameterization for subgrid-scale motion of ice-shelf calving fronts
In order to explore the response of the Greenland ice sheet (GIS) to climate change on long (centennial to multi-millennial) time scales, a regional energy-moisture balance model has been developed. This model simulates seasonal variations of temperature and precipitation over Greenland and explicitly accounts for elevation and albedo feedbacks. From these fields, the annual mean surface temperature and surface mass balance can be determined and used to force an ice sheet model. The melt component of the surface mass balance is computed here using both a positive degree day approach and a more physically-based alternative that includes insolation and albedo explicitly. As a validation of the climate model, we first simulated temperature and precipitation over Greenland for the prescribed, present-day topography. Our simulated climatology compares well to observations and does not differ significantly from that of a simple parameterization used in many previous simulations. Furthermore, the calculated surface mass balance using both melt schemes falls within the range of recent regional climate model results. For a prescribed, ice-free state, the differences in simulated climatology between the regional energy-moisture balance model and the simple parameterization become significant, with our model showing much stronger summer warming. When coupled to a three-dimensional ice sheet model and initialized with present-day conditions, the two melt schemes both allow realistic simulations of the present-day GIS
Was bringen Vernetzung und Kooperation fĂŒr die lokale Wirtschaftsentwicklung? - Bericht ĂŒber eine Tagung am IWH
The Department of Urban Economics of the Halle Institute for Economic Research (IWH) held on 2 and 3 December 2010 the third âHalle Forum on Urban Economic Growthâ. The biennial âHalle Forumâ focuses on the determinants of urban growth. This year's conference addressed the forms and benefits of cooperation and networking for the economic development of cities and metropolitan regions. The presentations and discussions focused on the one hand on the effects and determinants of inter-and intra-regional cooperation between firms, and on the other hand on cooperation between neighboring municipalities, especially through the establishment of metropolitan regions.
Inflationary Cosmological Perturbations of Quantum-Mechanical Origin
This review article aims at presenting the theory of inflation. We first
describe the background spacetime behavior during the slow-roll phase and
analyze how inflation ends and the Universe reheats. Then, we present the
theory of cosmological perturbations with special emphasis on their behavior
during inflation. In particular, we discuss the quantum-mechanical nature of
the fluctuations and show how the uncertainty principle fixes the amplitude of
the perturbations. In a next step, we calculate the inflationary power spectra
in the slow-roll approximation and compare these theoretical predictions to the
recent high accuracy measurements of the Cosmic Microwave Background radiation
(CMBR) anisotropy. We show how these data already constrain the underlying
inflationary high energy physics. Finally, we conclude with some speculations
about the trans-Planckian problem, arguing that this issue could allow us to
open a window on physical phenomena which have never been probed so far.Comment: Review Article, 47 pages, 3 figures. Lectures given at the 40th
Karpacz Winter School on Theoretical Physics (Poland, Feb. 2004), submitted
to Lecture Notes in Physic
Identification of Neutral B Mesons Using Correlated Hadrons
The identification of the flavor of a neutral meson can make use of
hadrons produced nearby in phase space. Examples include the decay of
``'' resonances or the production of hadrons as a result of the
fragmentation process. Some aspects of this method are discussed, including
time-dependent effects in neutral decays to flavor states, to eigenstates
of CP and to other states, and the effects of possible coherence between
and in the initial state. We study the behavior of the leading
hadrons in -quark jets and the expected properties of resonances.
These are extrapolated from the corresponding resonances, of whose
properties we suggest further studies.Comment: To be submitted to Phys. Rev. D. 26 pages, LaTeX, figures not
included (available upon request). Technion-PH-93-32 / EFI 93-4
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