998 resultados para Axel Gyldén


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In diesem Beitrag untersuchen wir den Zusammenhang zwischen dem Sozialkapitalbestand der 382 Gemeinden des Kantons Bern und deren wirtschaftlichen Prosperität. Als Indikator für das Sozialkapital verwenden wir die Anzahl an Vereinen. Nach unseren Recherchen gibt es im Kanton Bern insgesamt 10 130 Vereine. Die statistischen Analysen zeigen, dass selbst unter Kontrolle von weiteren Merkmalen Gemeinden mit vielen Vereinen über ein höheres Einkommen pro Einwohner verfügen. In einer Unterstichprobe von 100 Gemeinden wurde zusätzlich eine schriftliche Befragung von 2 577 Vereinen durchgeführt. Die Resultate ergeben, dass für den Wohlstand der Gemeinden insbesondere die Anzahl an aktiven Mitgliedern ausschlaggebend ist. Vereine mit Fokussierung auf das Gemeinwohl (Putnam-Vereine) haben zudem eine grössere Bedeutung für den Wohlstand als Vereine, die eher Partikularinteressen vertreten (Olson-Vereine). Insgesamt bestätigen die Ergebnisse die Sozialkapitalthese.

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Because neuronal nitric oxide synthase (nNOS) has a well-known impact on arteriolar blood flow in skeletal muscle, we compared the ultrastructure and the hemodynamics of/in the ensuing capillaries in the extensor digitorum longus (EDL) muscle of male nNOS-knockout (KO) mice and wild-type (WT) littermates. The capillary-to-fiber (C/F) ratio (-9.1%) was lower (P ≤ 0.05) in the nNOS-KO mice than in the WT mice, whereas the mean cross-sectional fiber area (-7.8%) and the capillary density (-3.1%) varied only nonsignificantly (P > 0.05). Morphometrical estimation of the area occupied by the capillaries as well as the volume and surface densities of the subcellular compartments differed nonsignificantly (P > 0.05) between the two strains. Intravital microscopy revealed neither the capillary diameter (+3% in nNOS-KO mice vs. WT mice) nor the mean velocity of red blood cells in EDL muscle (+25% in nNOS-KO mice vs. WT mice) to significantly vary (P > 0.05) between the two strains. The calculated shear stress in the capillaries was likewise nonsignificantly different (3.8 ± 2.2 dyn/cm² in nNOS-KO mice and 2.1 ± 2.2 dyn/cm² in WT mice; P > 0.05). The mRNA levels of vascular endothelial growth factor (VEGF)-A were lower in the EDL muscle of nNOS-KO mice than in the WT littermates (-37%; P ≤ 0.05), whereas mRNA levels of VEGF receptor-2 (VEGFR-2) (-11%), hypoxia inducible factor-1α (+9%), fibroblast growth factor-2 (-14%), and thrombospondin-1 (-10%) differed nonsignificantly (P > 0.05). Our findings support the contention that VEGF-A mRNA expression and C/F-ratio but not the ultrastructure or the hemodynamics of/in capillaries in skeletal muscle at basal conditions depend on the expression of nNOS.

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PURPOSE To assess ultrasmall superparamagnetic iron oxide particles (USPIO) -enhanced MR imaging for the differentiation of malignant from benign, inflammatory lesions. MATERIALS AND METHODS In this study, approved by the local animal care committee, VX2 carcinoma and intramuscular abscesses were implanted into the hind thighs of New Zealand White rabbits. MR imaging was performed pre contrast and serially for 24 h after the injection of USPIO. MR findings were compared with histopathologic results based on Prussian blue stains for the presence of iron. RESULTS Twenty-four hours after the Ferumoxtran-injection, no changes were observed in VX2 carcinomas, whereas a mean reduction of the contrast-to-noise ratio (CNR) of approximately 90% was noticed in abscesses as well as in necrotic tumors. On histopathologic examination, abscess and necrotic parts of the tumor were found to include iron-containing monocytes demonstrating that the reduction in CNR was caused by USPIO-tagged monocytes. CONCLUSION Our results prove the ability of USPIO-enhanced MRI to differentiate benign, inflammatory from malignant lesions.

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High reflective materials in the microwave region play a very important role in the realization of antenna reflectors for a broad range of applications, including radiometry. These reflectors have a characteristic emissivity which needs to be characterized accurately in order to perform a correct radiometric calibration of the instrument. Such a characterization can be performed by using open resonators, waveguide cavities or by radiometric measurements. The latter consists of comparative radiometric observations of absorbers, reference mirrors and the sample under test, or using the cold sky radiation as a direct reference source. While the first two mentioned techniques are suitable for the characterization of metal plates and mirrors, the latter has the advantages to be also applicable to soft materials. This paper describes how, through this radiometric techniques, it is possible to characterize the emissivity of the sample relative to a reference mirror and how to characterize the absolute emissivity of the latter by performing measurements at different incident angles. The results presented in this paper are based on our investigations on emissivity of a multilayer insulation material (MLI) for space mission, at the frequencies of 22 and 90 GHz.

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We present the design of a submillimeter-wave mixer based on electromagnetic band gap (EBG) technology and using subharmonic local oscillator (LO) injection. The indicated device converts an incoming submilimeter wavelength signal into a 1-5 GHz intermediate frequency (IF) signal by mixing it with a subharmonic LO signal. The mixer consists of a dual-band receiver and two coplanar stripline (CPS) filters, collocated on top of a three-dimensional (3-D) EBG structure. A four-element array of the proposed receivers was designed, fabricated and tested. The configuration demonstrated reasonable performance: conversion loss below 8 dB and noise temperature below 3000 K. The presented concept can be used for higher frequencies, provided the availability of sufficiently powerful LO sources.

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This paper presents the first analysis of the input impedance and radiation properties of a dipole antenna, placed on top of Fan 's three-dimensional electromagnetic bandgap (EBG) structure, (Applied Physics Letters, 1994) constructed using a high dielectric constant ceramic. The best position of the dipole on the EBG surface is determined following impedance and radiation pattern analyses. Based on this optimum configuration an integrated Schottky heterodyne detector was designed, manufactured and tested from 0.48 to 0.52 THz. The main antenna features were not degraded by the high dielectric constant substrate due to the use of the EBG approach. Measured radiation patterns are in good agreement with the predicted ones.

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We present a conceptual prototype model of a focal plane array unit for the STEAMR instrument, highlighting the challenges presented by the required high relative beam proximity of the instrument and focus on how edge-diffraction effects contribute to the array's performance. The analysis was carried out as a comparative process using both PO & PTD and MoM techniques. We first highlight general differences between these computational techniques, with the discussion focusing on diffractive edge effects for near-field imaging reflectors with high truncation. We then present the results of in-depth modeling analyses of the STEAMR focal plane array followed by near-field antenna measurements of a breadboard model of the array. The results of these near-field measurements agree well with both simulation techniques although MoM shows slightly higher complex beam coupling to the measurements than PO & PTD.