2,240 research outputs found
Antibodies to the alpha(1)-adrenergic receptor cause vascular impairments in rat brain as demonstrated by magnetic resonance angiography
BACKGROUND: Circulating agonistic autoantibodies acting at G protein-coupled receptors have been associated with numerous sever pathologies in humans. Antibodies directed predominantly against the alpha(1)-adrenergig receptor were detected in patients suffering from widespread diseases such as hypertension and type 2 diabetes. Their deleterious action has been demonstrated for peripheral organs. We postulate that antibodies to the alpha(1)-adrenergig receptor are relevant pathomolecules in diseases of the central nervous system associated with vascular impairments. METHODOLOGY/PRINCIPAL FINDINGS: Using a rat model we studied the long-term action of antibodies against the alpha(1)-adrenergig receptor either induced by immunization with a receptor peptide or applied by intravenous injection. The vasculature in the rat brains was investigated by time-of-flight magnetic resonance angiography using a 9.4 Tesla small animal MR imaging system. Visual examination of maximum-intensity-projections (MIPs) of brain angiographs revealed the development of vascular defects in antibody- exposed animals between three and eight months of treatment. Relative vascular areas were derived from representative MIP image sections by grayscale analysis and used to form an index of vascular circulation. Animals exposed to the action of alhpa(1)-adrenergig receptor antibodies showed significantly reduced vascular areas (p<0.05). Calculated index values indicated attenuated blood flow in both antibody-treated cohorts compared to their respective controls reaching with (relative units ± standard error, nâ=â10) 0.839±0.026 versus 0.919±0.026 statistical significance (p<0.05) for peptide-immunized rats. CONCLUSION/SIGNIFICANCE: We present evidence that antibodies to the α(1)-adrenergig receptor cause cerebrovascular impairments in the rat. Our findings suggest the pathological significance of these antibodies in pathologies of the human central nervous system linked to impairments of brain vasculature such as stroke and dementia
The Spectral Energy Distribution of Self-gravitating Interstellar Clouds I. Spheres
We derive the spectral energy distribution (SED) of dusty, isothermal, self
gravitating, stable and spherical clouds externally heated by the ambient
interstellar radiation field. For a given radiation field and dust properties,
the radiative transfer problem is determined by the pressure of the surrounding
medium and the cloud mass expressed as a fraction of the maximum stable cloud
mass above which the clouds become gravitational unstable.
To solve the radiative transfer problem a ray-tracing code is used to
accurately derive the light distribution inside the cloud. This code considers
both non isotropic scattering on dust grains and multiple scattering events.
The dust properties inside the clouds are assumed to be the same as in the
diffuse interstellar medium in our galaxy. We analyse the effect of the
pressure, the critical mass fraction, and the ISRF on the SED and present
brightness profiles in the visible, the IR/FIR and the submm/mm regime with the
focus on the scattered emission and the thermal emission from PAH-molecules and
dust grains.Comment: accepted for publication in ApJS, May 2008, v176n1 issu
The paradox of tenant empowerment: regulatory and liberatory possibilities
Tenant empowerment has traditionally been regarded as a means of realising democratic ideals: a quantitative increase in influence and control, which thereby enables "subjects" to acquire the fundamental properties of "citizens". By contrast governmentality, as derived from the work of Michel Foucault, offers a more critical appraisal of the concept of empowerment by highlighting how it is itself a mode of subjection and a means of regulating human conduct towards particular ends. Drawing on particular data about how housing governance has changed in Glasgow following its 2003 stock transfer, this paper adopts the insights of governmentality to illustrate how the political ambition of "community ownership" has been realized through the mobilization and shaping of active tenant involvement in the local decision making process. In addition, it also traces the tensions and conflict inherent in the reconfiguration of power relations post-transfer for "subjects" do not necessarily conform to the plans of those that seek to govern them
Fertigung laminarer optischer Gitter am HZB
Laminare optische Gitter stellen höchste Anforderungen an die mikrosystemtechnische Fertigung der Mikro und Nano strukturen in Hinsicht auf PrĂ€zision und HomogenitĂ€t. Im Rahmen des EU Projektes Aufbau eines Technologiezent rums fĂŒr hocheffiziente optische PrĂ€zisionsgitter am Helmholtz Zentrum Berlin HZB EFRE Vertrag Nr. 20072013 2 43 [1,2] wurden die fĂŒr die Herstellung von laminaren und geblazten Gittern notwendigen Anlagen in Betrieb ge nommen. Gleichzeitig wurde mit der Prozessentwicklung begonnen. In diesem Artikel werden die neuesten Prozessergebnisse von durch Laserinterferenzlithographie LIL in Photoresist erzeugter Gitterstrukturen und deren nur wenige Nanometer tiefe Ăbertragung in Siliziumsubstrate mittels Ionenstrahl Ă€tzen vorgestellt. english version Laminar optical gratings impose highest demands on microsystem technological manufacturing with regard to precision and uniformity. Within the project Installation of a technology centre for highly efficient precision gratings at Helm holtz Zentrum Berlin HZB EFRE Vertrag Nr. 20072013 2 43 [1,2] the necessary systems for the manufacturing of laminar and blazed gratings were taken into operation and process development has started. In this article we present the results of grating structures manufactured with laser interference lithography and subse quent ion beam etchin
A Deep VLA survey at 20cm of the ISO ELAIS survey regions
We have used the Very Large Array(VLA) in C configuration to carry out a
sensitive 20cm radio survey of regions of sky that have been surveyed in the
Far Infra-Red over the wavelength range 5-200 microns with ISO as part of the
European Large Area ISO Survey(ELAIS). As usual in surveys based on a
relatively small number of overlapping VLA pointings the flux limit varies over
the area surveyed. The survey has a flux limit that varies from a 5
limit of 0.135mJy over an area of 0.12deg to a 5 limit of 1.15mJy
or better over the whole region covered of 4.22 deg. In this paper we
present the radio catalogue of 867 sources. These regions of sky have
previously been surveyed to shallow flux limits at 20cm with the VLA as part of
the VLA D configuration NVSS(FWHM=45 arcsec) and VLA B configuration
FIRST(FWHM=5 arcsec) surveys. We have carried out a a detailed comparison of
the reliability of our own survey and these two independent surveys in order to
assess the reliability and completeness of each survey.Comment: 19 pages, 24 figures, submitted to MNRAS, also available in
http://www.ast.cam.ac.uk/~ciliegi/elais/paper
Post-Foucauldian governmentality: what does it offer critical social policy analysis?
This article considers the theoretical perspective of post-Foucauldian governmentality, especially the insights and challenges it poses for applied researchers within the critical social policy tradition. The article firstly examines the analytical strengths of this approach to understanding power and rule in contemporary society, before moving on to consider its limitations for social policy. It concludes by arguing that these insights can be retained, and some of the weaknesses overcome, by adopting a ârealist governmentalityâ approach (Stenson 2005, 2008). This advocates combining traditional discursive analysis with more ethnographic methods in order to render visible the concrete activity of governing, and unravel the messiness, complexity and unintended consequences involved in the struggles around subjectivity
The far-infrared energy distributions of Seyfert and starburst galaxies in the Local Universe: ISO photometry of the 12 micron active galaxy sample
New far-infrared photometry with ISOPHOT, onboard the Infrared Space
Observatory, is presented for 58 galaxies with homogeneous published data for
another 32 galaxies all belonging to the 12 micron galaxy sample. In total 29
Seyfert 1's, 35 Seyfert 2's and 12 starburst galaxies, about half of the 12
micron active galaxy sample, plus 14 normal galaxies for comparison. The ISO
and the IRAS data are used to define color-color diagrams and spectral energy
distributions (SED). Thermal dust emission at two temperatures (one cold at
15-30K and one warm at 50-70K) can fit the 60-200 micron SED, with a dust
emissivity law proportional to the inverse square of the wavelength. Seyfert
1's and Seyfert 2's are indistinguishable longward of 100 micron, while, as
already seen by IRAS, the former have flatter SEDs shortward of 60 micron. A
mild anti-correlation is found between the [200 - 100] color and the "60 micron
excess". We infer that this is due to the fact that galaxies with a strong
starburst component, and thus a strong 60 micron flux, have a steeper
far-infrared turnover. In non-Seyfert galaxies, increasing the luminosity
corresponds to increasing the star formation rate, that enhances the 25 and 60
micron emission. This shifts the peak emission from around 150 micron in the
most quiescent spirals to shorter than 60 micron in the strongest starburst
galaxies.Comment: Accepted for publication in The Astrophysical Journal AASTeX preprint
with 49 pages and 20 figures Also available at
http://orion.ifsi.rm.cnr.it/publ.htm
Vanishing Fe 3d orbital moments in single-crystalline magnetite
We show detailed magnetic absorption spectroscopy results of an in situ
cleaved high quality single crystal of magnetite. In addition the experimental
setup was carefully optimized to reduce drift, self absorption, and offset
phenomena as far as possible. In strong contradiction to recently published
data, our observed orbital moments are nearly vanishing and the spin moments
are quite close to the integer values proposed by theory. This very important
issue supports the half metallic full spin polarized picture of magnetite.Comment: 7 pages, 4 figure
Genetic differences in the frequency of the hinge variants of porcine IgA is breed dependent
The distribution of the IgAa and IgAb alleles of porcine IgA in over 160 randomly-selected animals revealed an abundance of heterozygotes but only two b/b homozygotes. Since the IgAb allotype is a splice site mutant lacking two-thirds of the hinge, this study tests the hypothesis that pigs with this genotype may be at a selective disadvantage while heterozygous individuals may be at some advantage.
This hypothesis was tested by collecting data on 374 animals of known breed and often parentage. We show here that when breed was not considered, young animals of known parentage had genotypic frequencies identical to that expected for Mendelian alleles but that a/b heterozygotes were overrepresented in adults. However, when analyzed with regard to breed, a very strong association between breed and the frequency of the IgAa and IgAb alleles was discovered. Meishan and NIH minipigs were homozygous for IgA while heterozygotes predominated in Berkshire, Chester White, Durocs, Hampshire and Landrace. Animals homozygous for IgAb were best represented in the White Cross line. We show here that this very strong breed dependency of IgA allotypy in swine can produce a sample bias that can explain why only two b/b homozygotes (1.3%) were found in the 160 randomly-selected samples since the original samples came from primarily Landrace and Yorkshire animals. The expected frequency of b/b homozygotes in these breeds would be \u3c3%. Thus, the data presented here reject the hypothesis that swine homozygous for a trait that results in loss of two-thirds of the IgA hinge, are selected against and that heterozygotes are positively selected. Rather, the study shows that IgAa and IgAb appear to be simple, breed-dependent allotypic markers
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