2,783 research outputs found
Lorentz shift measurements in heavily irradiated silicon detectors in high magnetic fields
An external magnetic field exerts a Lorentz force on drifting electric
charges inside a silicon strip sensor and thus shifts the cluster position of
the collected charge. The shift can be related to the Lorentz angle which is
typically a few degrees for holes and a few tens of degrees for electrons in a
4 T magnetic field. The Lorentz angle depends upon magnetic field, electric
field inside the sensor and temperature. In this study the sensitivity to
radiation for fluences up to 10^16 n/cm^2 has been studied. The Lorentz shift
has been measured by inducing ionization with 670 nm red or 1070 nm infrared
laser beams injected into the back side of the irradiated silicon sensor
operated in magnetic fields up to 8 T. For holes the shift as a function of
radiation is increasing, while for electrons it is decreasing and even changes
sign. The fact that for irradiated sensors the Lorentz shift for electrons is
smaller than for holes, in contrast to the observations in non-irradiated
sensors, can be qualitatively explained by the structure of the electric field
in irradiated sensors.Comment: Accepted publication for RD09 conference in Proceedings of Scienc
Channelized and hillslope sediment transport and the geomorphology of mountain belts
This paper uses the results of landscape evolution models and morphometric data from the Andes of northern Peru and the eastern Swiss Alps to illustrate how the ratio between sediment transport on hillslopes and in channels influences landscape and channel network morphologies and dynamics. The headwaters of fluvial- and debris-flow-dominated systems (channelized processes) are characterized by rough, high-relief, highly incised surfaces which contain a dense and hence a closely spaced channel network. Also, these systems tend to respond rapidly to modifications in external forcing (e.g., rock uplift and/or precipitation). This is the case because the high channel density results in a high bulk diffusivity. In contrast, headwaters where landsliding is an important sediment source are characterized by a low channel density and by rather straight and unstable channels. In addition, the topographies are generally smooth. The low channel density then results in a relatively low bulk diffusivity. As a consequence, response times are greater in headwaters of landslide-dominated systems than in highly dissected drainages. The Peruvian and Swiss case studies show how regional differences in climate and the litho-tectonic architecture potentially exert contrasting controls on the relative importance of channelized versus hillslope processes and thus on the overall geomorphometry. Specifically, the Peruvian example illustrates to what extent the storminess of climate has influenced production and transport of sediment on hillslopes and in channels, and how these differences are seen in the morphometry of the landscape. The Swiss example shows how the bedding orientation of the bedrock drives channelized and hillslope processes to contrasting extents, and how these differences are mirrored in the landscap
Air temperature and inflammatory and coagulation responses in men with coronary or pulmonary disease during the winter season
Background and Objective Air temperature changes are associated with increased cardiovascular and respiratory risk, but the roles of inflammatory and coagulation markers are not well understood. We investigated the associations between temperature and several blood markers in patients with coronary heart disease (CHD) and pulmonary disease (PD). Methods Two studies were conducted in Erfurt, Germany, over two successive winters. 578 and 381 repeated blood measurements were collected from 57 CHD and 38 PD patients, respectively. Data on patient characteristics and disease history were gathered at baseline. Meteorological data were collected from existing networks. Associations were analysed using additive mixed models with random patient effects. Effect modification by diabetes status was investigated only in CHD patients, as only two PD patients had diabetes. Results Mean daily air temperature varied between -13 degrees C and 16 degrees C in both study periods. A 10 degrees C decrease in the 5-day temperature average before blood withdrawal led to an increase in platelet counts (% change from the mean: 3.0%, 95% CI 0.6% to 5.5%) and fibrinogen (5.5%, 1.3% to 9.7%), no change in C-reactive protein in PD patients, and a decrease in C-reactive protein in CHD patients. A 2-day delayed increase in factor VII associated with temperature decrease was seen in CHD patients (4.9%; 0.7% to 9.2%), while PD patients showed no effect. `Effects in CHD patients without diabetes' into `Effects on factor VII in CHD patients without diabetes'. Conclusions This study suggests that temperature decrease is associated with change in several blood parameters. The complex interplay of blood markers at low temperature may contribute to the observed association between cold and cardiovascular mortality and morbidity
Wozu (heute noch) Gewerkschaften, Tarifautonomie und Flächentarifverträge?
Am 10. und 11. Dezember 2004 veranstaltete die Akademie für Politische Bildung Tutzing eine Konferenz zu dem Thema "Wozu (heute noch) Gewerkschaften, Tarifautonomie und Flächentarifverträge". Im Mittelpunkt des ersten Tages stand die Frage nach der Reformfähigkeit bzw. -notwendigkeit des deutschen Systems der Sozialpartnerschaft, damit es auch längerfristig als positiver Standortfaktor wirken kann. Prof. Dr. Wernhard Möschel, Universität Tübingen, unterstrich in seinem Referat, dass Gewerkschaften und Arbeitergeberverbände als Kartelle und als ordnungspolitisch überholte Modelle zu sehen seien: "Die reformatorische Zukunft sollte nicht den Kollektivsystemen Tarifvertrag oder Betriebsvereinbarung gehören. Beide sind korporatistisch definiert. Vielmehr sollte der individuelle Arbeitsvertrag stärker ins Blickfeld rücken. Es geht darum, die Privatautonomie, die außerhalb der Arbeitswelt unsere gesamte Rechts- und Wirtschaftsordnung prägt, von unnötigen Fesseln zu befreien, dies zum Wohle aller." Im Gegensatz dazu unterstrich em. Prof. Dr. Heinz Lampert, Universität Augsburg, in seinem Referat den Beitrag der Gewerkschaften zum sozialen Frieden und zum sozialem Ausgleich in der Gesellschaft: "Der Verfasser ist überzeugt, dass die Wohlfahrt beachtlich großer Teile unserer Gesellschaft durch wesentliche Einschränkungen der Aktionsmöglichkeiten der Gewerkschaften erheblich beeinträchtigt werden würde." Auch Prof. Dr. Michael Schneider, Friedrich-Ebert-Stiftung, hebt vor allem die Bereitschaft der Gewerkschaften hervor, "Verantwortung für das Ganze zu übernehmen".Gewerkschaft, Gewerkschaftliche Organisation, Tarifautonomie, Tarifvertrag, Arbeitnehmer, Sozialer Konflikt, Deutschland
Quasiparticle Description of Hot QCD at Finite Quark Chemical Potential
We study the extension of a phenomenologically successful quasiparticle model
that describes lattice results of the equation of state of the deconfined phase
of QCD for Tc <= T < 4 Tc, to finite quark chemical potential mu. The phase
boundary line Tc(mu), the pressure difference (p(T,mu)-p(T,mu=0))/T^4 and the
quark number density nq(T,mu)/T^3 are calculated and compared to recent lattice
results. Good agreement is found up to quark chemical potentials of order mu =
Tc.Comment: 12 pages, 7 figures; added reference
Effects of green tea catechins on the pro-inflammatory response after haemorrhage/resuscitation in rats
Plant polyphenols, i.e. green tea extract (GTE), possess high antioxidative and anti-inflammatory capacity, thus being protective in various models of acute inflammation. However, their anti-inflammatory effect and a feasible mechanism in haemorrhage/resuscitation (H/R)-induced liver injury remain unknown. We investigated the effects of GTE and the role of NF-κB in the pathogenesis of liver injury induced by H/R, and their effects on intercellular adhesion molecule-1 (ICAM-1) expression and neutrophil infiltration. Female Lewis rats were fed a standard chow diet (control, ctrl) or a diet containing 0·1% polyphenolic GTE for five consecutive days before H/R. Rats were haemorrhaged to a mean arterial pressure of 30 (sem 2)mmHg for 60min and resuscitated. Control groups (sham_ctrl and sham_GTE) underwent surgical procedures without H/R. At 2h after resuscitation, tissues were harvested. Serum alanine aminotransferase (ALT) and IL-6 were measured. Hepatic necrosis, ICAM-1 expression and polymorphonuclear leucocyte (PMNL) infiltration were assessed. Hepatic expression of IκBα (phospho) was measured. H/R induced strong liver damage with increased necrosis and serum ALT levels. Compared with both sham groups, inflammatory markers (serum IL-6 and hepatic PMNL infiltration) were elevated after H/R (P<0·05). Also, H/R increased IκBα phosphorylation. GTE administration markedly (P<0·05) decreased serum ALT and IL-6 levels, hepatic necrosis as well as PMNL infiltration and the expression of ICAM-1 and phosphorylated IκBα compared with H/R. In conclusion, we observed that NF-κB activation plays an important role in the pathogenesis of liver injury after H/R through the up-regulation of hepatic ICAM-1 expression and subsequent PMNL infiltration. GTE pre-treatment prevents liver damage in this model of acute inflammation through a NF-κB-dependent mechanis
Contrasting sediment flux in Val Lumnezia (Graubünden, Eastern Swiss Alps), and implications for landscape development
This paper presents qualitative estimates of sediment discharge from opposite valley flanks in the S-N-oriented Val Lumnezia, eastern Swiss Alps, and relates inferred differences in sediment flux to the litho-tectonic architecture of bedrock. The valley flank on the western side hosts the deep-seated Lumnezia landslide where an area of ca. 30km2 has experienced slip rates of several centimetres per year, potentially resulting in high sediment discharge to the trunk stream (i.e. the Glogn River). High slip rates have resulted in topographic changes that are detectable on aerial photographs and measurable with geodetic tools. In contrast, a network of tributary channels dissects the valley flank on the eastern side. There, an area of approximately 18km2 corresponding to < 30% of the surface has experienced a change in the landscape mainly by rock avalanche and rock fall, and the magnitudes of changes are below the calibration limit of digital photogrammetry. We thus infer lower magnitudes of sediment discharge on the eastern tributaries than on the western valley side, where landsliding has been the predominant erosional process. These differences are interpreted to be controlled by the dip-slope situation of bedrock on the western side that favours down-slope slip of material. Morphometric investigations reveal that the western valley side is characterized by a low topographic roughness because this valley flank has not been dissected by a channel network. It appears that high sediment discharge of the Lumnezia landslide has inhibited the establishment of a stable channel network and has largely controlled the overall evolution of the landscape. This contrasts to the general notion that channelized processes exert the first-order control on landscape evolution and formation of relief and needs to be considered in future studies about landscape architecture, drainage network and sediment discharg
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