3,355 research outputs found

    Effects of fluctuations on the initial eccentricity from the Color Glass Condensate in heavy ion collisions

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    We introduce a modified form of the Kharzeev-Levin-Nardi (KLN) approach for nuclear collisions. The new ansatz for the unintegrated gluon distribution function preserves factorization, and the saturation scale is bound from below by that for a single nucleon. It also reproduces the correct scaling with the number of collisions at high transverse momentum. The corresponding Monte Carlo implementation allows us to account for fluctuations of the hard sources (nucleons) in the transverse plane. We compute various definitions of the eccentricity within the new approach, which are relevant for the interpretation of the elliptic flow. Our approach predicts breaking of the scaling of the eccentricity with the Glauber eccentricity at the level of about 30%.Comment: 9 pages, 10 figures, Updated version as accepted by Phys.Rev.

    Space and Collective Identities

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    Sowohl Identitäts- als auch Raumkonzepte haben in den einzelnen Wissenschaften bereits verschiedene Konjunkturen durchlaufen. Eine intensive Diskussion über ihre aktuelle Definition sowie die Möglichkeiten und Grenzen ihrer Anwendung in den Altertumswissenschaften fehlt jedoch bislang weitgehend. Die im Sommer 2009 gegründete Cross Sectional Group V (CSG-V) bietet hierfür einen Kommunikationsraum. Für einen die Topoi-Areas übergreifenden Austausch wurden spezielle Kommunikationsformate etabliert, z. B. ein monatlich stattfindendes Forum, ein Lesezirkel und Seminare. Ziel ist es u. a., auf methodisch- konzeptionellem Wege das Kernproblem der Verbindung von räumlich verorteter materieller Kultur mit kollektiven Identitäten zu untersuchen. Häufig wurden und werden hier Identifizierungen vorgenommen, die unreflektiert und ideologisch-politisch aufgeladen sind. Ebenso müssen neue Erkenntnisse aus den Naturwissenschaften methodenkritisch in die Forschung integriert werden, auch um mit den wieder verstärkt auftretenden biologistischen Vorstellungen angemessen umgehen zu können. Dazu ist eine Auseinandersetzung mit wissenschaftsgeschichtlichen Fragestellungen und zeitgeschichtlichen, auf archäologischen Orten und archäologischen Wissensproduktionen basierenden Konstitutionen von Identitäten notwendig. Ferner stellen die Erforschung von Kulturtransfer, durch den die Dynamik von Identitäten und Raum verdeutlicht wird, sowie von sprachlichen und narrativen Identitätsdiskursen, z. B. in Form von Eponymen und Mythen, zentrale Aspekte der Arbeit der CSG-V dar. Aufgrund der Aufgabenstellung der CSG-V werden im Folgenden vor allem der diskutierte Raum- und Identitätsbegriff sowie ihre sechs Arbeitskomponenten vorgestellt und erst dann einige Schwerpunktthemen kurz behandelt

    Alpha-Lipoic Acid for the Prevention of Diabetic Macular Edema

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    Introduction: To evaluate the effect of alpha-lipoic acid (ALA) on the occurrence of diabetic macular edema. Methods: Randomized, double-blind, placebo-controlled, multicenter, multinational study. Patients were randomized to the treatment group with 600 mg ALA per day or the placebo group. Every 6 months stereo fundus photographs, HbA1c levels, and an ophthalmological examination were documented. The primary endpoint was the occurrence of clinically significant macular edema (CSME) within a follow-up period of 2 years. Results: We randomized 235 patients with type II diabetes mellitus into the treatment group (mean age 58.0 years) and 232 into the placebo group (mean age 57.9 years). Mean HbA1c level was 8.1, with no significant differences between the treatment (mean 8.2, SD +/- 1.35) and placebo groups (mean 8.1, SD +/- 1.29). HbA1c values remained constant over time. In the treatment and placebo groups, 84 and 86 patients (35.7 and 37.1%) had insulin-dependent diabetes mellitus (IDDM) with a median duration of diabetes of 9.3 versus 9.0 years in the placebo group. Visual acuity remained unchanged during the entire trial. Concerning the primary endpoint, the study provided a negative result, i.e. 26/235 patients in the treatment group and 30/232 patients in the placebo group developed CSME. Confirmatory intention-to-treat analysis of the primary endpoint revealed no statistically significant difference between groups (log-rank test, p = 0.7108, HR = 0.9057 with CI = 0.5355-1.5317). Median follow-up was identical (2.00 years). Conclusions: A daily dosage of 600 mg ALA does not prevent the occurrence of CSME in IDDM patients. Copyright (C) 2011 S. Karger AG, Base

    Genetic Modification of Herbaceous Plants for Feed and Fuel

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    Much of the research on the genetic modification of herbaceous plant cell walls has been conducted to improve the utilization of forages by ruminant livestock. The rumen of these animals is basically an anaerobic fermentation vat in which the microflora break down the complex polysaccharides of plant cell walls into simpler compounds that can be further digested and absorbed by the mammalian digestive system. Research on improving the forage digestibility of switchgrass, Panicum virgatum L., and other herbaceous species has demonstrated that genetic improvements can be made in forage quality that can have significant economic value. To meet future energy needs, herbaceous biomass will need to be converted into a liquid fuel, probably ethanol, via conversion technologies still under development. If feedstock quality can be genetically improved, the economics and efficiency of the conversion processes could be significantly enhanced. Improving an agricultural product for improved end product use via genetic modification requires knowledge of desired quality attributes, the relative economic value of the quality parameters in relation to yield, genetic variation for the desired traits, or for molecular breeding, knowledge of genes to suppress or add, and knowledge of any associated negative consequences of genetic manipulation. Because conversion technology is still under development, desirable plant feedstock characteristics have not been completely delineated. Some traits such as cellulose and lignin concentration will undoubtably be important. Once traits that affect biomass feedstock conversion are identified, it will be highly feasible to genetically modify the feedstock quality of herbaceous plants using both conventional and molecular breeding techniques. The use of molecular markers and transformation technology will greatly enhance the capability of breeders to modify the morphologic structure and cell walls of herbaceous species. It will be necessary to monitor gene flow to remnant wild populations of biomass plants and have strategies available to curtail gene flow if it becomes a potential problem. It will also be necessary to monitor plant survival and longterm productivity as affected by these genetic changes to herbaceous species

    Broad-Scale Climate Influences on Spring-Spawning Herring (Clupea harengus, L.) Recruitment in the Western Baltic Sea

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    Climate forcing in complex ecosystems can have profound implications for ecosystem sustainability and may thus challenge a precautionary ecosystem management. Climatic influences documented to affect various ecological functions on a global scale, may themselves be observed on quantitative or qualitative scales including regime shifts in complex marine ecosystems. This study investigates the potential climatic impact on the reproduction success of spring-spawning herring (Clupea harengus) in the Western Baltic Sea (WBSS herring). To test for climate effects on reproduction success, the regionally determined and scientifically well-documented spawning grounds of WBSS herring represent an ideal model system. Climate effects on herring reproduction were investigated using two global indices of atmospheric variability and sea surface temperature, represented by the North Atlantic Oscillation (NAO) and the Atlantic Multi-decadal Oscillation (AMO), respectively, and the Baltic Sea Index (BSI) which is a regional-scale atmospheric index for the Baltic Sea. Moreover, we combined a traditional approach with modern time series analysis based on a recruitment model connecting parental population components with reproduction success. Generalized transfer functions (ARIMAX models) allowed evaluating the dynamic nature of exogenous climate processes interacting with the endogenous recruitment process. Using different model selection criteria our results reveal that in contrast to NAO and AMO, the BSI shows a significant positive but delayed signal on the annual dynamics of herring recruitment. The westward influence of the Siberian high is considered strongly suppressing the influence of the NAO in this area leading to a higher explanatory power of the BSI reflecting the atmospheric pressure regime on a North-South transect between Oslo, Norway and Szczecin, Poland. We suggest incorporating climate-induced effects into stock and risk assessments and management strategies as part of the EU ecosystem approach to support sustainable herring fisheries in the Western Baltic Sea

    Evolution of iron carbides during tempering of low-alloy tool steel studied with polarized small angle neutron scattering, electron microscopy and atom probe

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    The magnetic scattering of iron carbides in low-alloy tool steel was investigated ex-situ by polarized small angle neutron scattering measurements after tempering the steel at 550 \ub0C and 600 \ub0C. Magnetic features could be detected in the as-quenched sample resulting in a negative interference term, believed to be either θ-Fe3C, η-Fe2C, or ε-Fe2-3C. During tempering the evolution of cementite could be studied by the variation of the interference term and in γ-ratio, which is the ratio of the magnetic to nuclear scattering length density contrast. From scanning transmission electron microscopy (STEM) and atom probe tomography, it is evident that cementite (θ-Fe3C) is present directly when reaching the tempering temperature of either 550 \ub0C or 600 \ub0C. At longer tempering times, cementite gets enriched with substitutional elements like chromium and manganese, forming an enriched shell on the cementite particles. STEM and energy dispersive x-ray spectrometry show that the chemical composition of small cementite particles approaches that of Cr-rich M7C3 carbides after 24 h at 600 \ub0C. It is also seen that small non-magnetic particles precipitate during tempering and these correspond well with molybdenum and vanadium-rich carbides

    Systematic analysis of a novel human renal glomerulus-enriched gene expression dataset.

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    Glomerular diseases account for the majority of cases with chronic renal failure. Several genes have been identified with key relevance for glomerular function. Quite a few of these genes show a specific or preferential mRNA expression in the renal glomerulus. To identify additional candidate genes involved in glomerular function in humans we generated a human renal glomerulus-enriched gene expression dataset (REGGED) by comparing gene expression profiles from human glomeruli and tubulointerstitium obtained from six transplant living donors using Affymetrix HG-U133A arrays. This analysis resulted in 677 genes with prominent overrepresentation in the glomerulus. Genes with 'a priori' known prominent glomerular expression served for validation and were all found in the novel dataset (e.g. CDKN1, DAG1, DDN, EHD3, MYH9, NES, NPHS1, NPHS2, PDPN, PLA2R1, PLCE1, PODXL, PTPRO, SYNPO, TCF21, TJP1, WT1). The mRNA expression of several novel glomerulus-enriched genes in REGGED was validated by qRT-PCR. Gene ontology and pathway analysis identified biological processes previously not reported to be of relevance in glomeruli of healthy human adult kidneys including among others axon guidance. This finding was further validated by assessing the expression of the axon guidance molecules neuritin (NRN1) and roundabout receptor ROBO1 and -2. In diabetic nephropathy, a prevalent glomerulopathy, differential regulation of glomerular ROBO2 mRNA was found.In summary, novel transcripts with predominant expression in the human glomerulus could be identified using a comparative strategy on microdissected nephrons. A systematic analysis of this glomerulus-specific gene expression dataset allows the detection of target molecules and biological processes involved in glomerular biology and renal disease

    The Immune System in Tissue Environments Regaining Homeostasis after Injury: Is "Inflammation" Always Inflammation?

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    Inflammation is a response to infections or tissue injuries. Inflammation was once defined by clinical signs, later by the presence of leukocytes, and nowadays by expression of "proinflammatory" cytokines and chemokines. But leukocytes and cytokines often have rather anti-inflammatory, proregenerative, and homeostatic effects. Is there a need to redefine "inflammation"? In this review, we discuss the functions of "inflammatory" mediators/regulators of the innate immune system that determine tissue environments to fulfill the need of the tissue while regaining homeostasis after injury

    Signature analysis and test scheduling for self-testable circuits

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    In complex circuits the test execution is usually divided into a number of subtasks, each producing a signature in a self-test register. These signatures influence one another. A model that can be used as a basis for test scheduling procedures is presented, and it is shown how test schedules can be constructed, in order to minimize the number of signatures to be evaluated. The error masking probabilities decrease when the subtasks of the test execution are repeated in an appropriate order, and an equilibrium situation is reached where the error masking probabilities are minimal. A method is presented for constructing test schedules so that only the signatures at the primary outputs must be evaluated to get a sufficient fault coverage. Then no internal scan path is required, only a few signatures have to be evaluated at the end of the test execution, and the test control at chip and board level is simplified. The amount of hardware to implement a built-in self-test is reduced significantly
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