3,461 research outputs found

    Biochemische Serumparameter bei in Gefangenschaft gehaltenen Gazellen

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    Objective: This study aimed at comparing serum parameters of clinically healthy gazelles of Al Wabra Wildlife Preservation (AWWP), Qatar, with reference ranges of domestic and other wild ruminants, in order to gain, on the one hand, insight into the nutritional status of the animals, and, on the other hand, to establish reference ranges for the investigated species. Material and methods: Serum biochemistry parameters and mineral levels were measured in 250 clinically healthy individuals of the species Soemmering's gazelle (Gazella soemmerringii), Speke's gazelle (Gazella spekei), Dorcas gazelle (Gazella dorcas), Saudi gazelle (Gazella saudiya), Mountain gazelle (Gazella gazella), Arabian goitered gazelle (Gazella subgutturosa marica) and Chinkara Pakistani gazelle (Gazella benetti). Results: With respect to the nutritional status, the supplementation with trace elements (selenium, copper, zinc, iron) was adequate at AWWP according to measured serum levels. In contrast, serum levels of phosphorus, total protein and albumin indicated a suboptimal feeding situation, most likely due to the low quality of the roughage available in the region. The levels of sodium, potassium, calcium, magnesium, choride, triglycerides, cholesterol, creatinine, ALT- as well as GGT avtivity were -as in other wild ruminants-within the reference range of domestic ruminants, which therefore should be applicable to ruminants in general. The contents of glucose, blood urea nitrogen, creatine kinase and ALP, in contrast, seem to be generally elevated in wild ruminants. While other wild ruminants display an AST activity comparable to those of domestic ruminants, gazelles of both this and other studies had elevated values of this enzyme. Conclusion and clinical relevance: These peculiarities need to be accounted for when interpreting blood values

    Recent Developments in the Nuclear Many-Body Problem

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    The study of quantum chromodynamics (QCD) over the past quarter century has had relatively little impact on the traditional approach to the low-energy nuclear many-body problem. Recent developments are changing this situation. New experimental capabilities and theoretical approaches are opening windows into the richness of many-body phenomena in QCD. A common theme is the use of effective field theory (EFT) methods, which exploit the separation of scales in physical systems. At low energies, effective field theory can explain how existing phenomenology emerges from QCD and how to refine it systematically. More generally, the application of EFT methods to many-body problems promises insight into the analytic structure of observables, the identification of new expansion parameters, and a consistent organization of many-body corrections, with reliable error estimates.Comment: 15 pages, 10 figures, plenary talk at the 11th Conference on Recent Progress in Many-Body Theories (MB 11), Manchester, England, 9-13 Jul 200

    Deformation of grain boundaries in polar ice

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    The ice microstructure (grain boundaries) is a key feature used to study ice evolution and to investigate past climatic changes. We studied a deep ice core, in Dome Concordia, Antarctica, which records past mechanical deformations. We measured a "texture tensor" which characterizes the pattern geometry and reveals local heterogeneities of deformation along the core. These results question key assumptions of the current models used for dating

    The Radio-to-Submm Spectral Index as a Redshift Indicator

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    We present models of the 1.4 GHz to 350 GHz spectral index, alpha(350/1.4), for starburst galaxies as a function of redshift. The models include a semi-analytic formulation, based on the well quantified radio-to-far infrared correlation for low redshift star forming galaxies, and an empirical formulation, based on the observed spectrum of the starburst galaxies M82 and Arp 220. We compare the models to the observed values of alpha(350/1.4) for starburst galaxies at low and high redshift. We find reasonable agreement between the models and the observations, and in particular, that an observed spectral index of alpha(350/1.4) > +0.5 indicates that the target source is likely to be at high redshift, z > 1. The evolution of alpha(350/1.4) with redshift is mainly due to the very steep rise in the Raleigh-Jeans portion of the thermal dust spectrum shifting into the 350 GHz band with increasing redshift. We also discuss situations where this relationship could be violated. We then apply our models to examine the putative identifications of submm sources in the Hubble Deep Field, and conclude that the submm sources reported by Hughes et al. are likely to be at high redshifts, z > 1.5.Comment: standard LATEX file plus 1 postscript figure. Added references and revised figure. second figure revision. Final Proof version. to appear in Astrophysical Journal Letter

    The size of the proton - closing in on the radius puzzle

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    We analyze the recent electron-proton scattering data from Mainz using a dispersive framework that respects the constraints from analyticity and unitarity on the nucleon structure. We also perform a continued fraction analysis of these data. We find a small electric proton charge radius, r_E^p = 0.84_{-0.01}^{+0.01} fm, consistent with the recent determination from muonic hydrogen measurements and earlier dispersive analyses. We also extract the proton magnetic radius, r_M^p = 0.86_{-0.03}^{+0.02} fm, consistent with earlier determinations based on dispersion relations.Comment: 4 pages, 2 figures, fit improved, small modifications, section on continued fractions modified, conclusions on the proton charge radius unchanged, version accepted for publication in European Physical Journal

    Long-term changes in the acid and salt concentrations of the Greenland Ice Core Project ice core from electrical stratigraphy

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    Continuous electrical records covering a climatic cycle are presented for the Greenland Ice Core Project deep ice core from Greenland. Electrical conductivity measurement (ECM) measures the acid content of the ice, and the dielectric profile (DEP) responds to acid, ammonium, and chloride. All features seen can be explained by chemical changes in the ice, and there is no evidence so far for any major change in electrical response with depth or age of the ice. Both records are dominated by the acidity of the ice which varies strongly from acidic in warm periods to alkaline in cold periods, controlled by neutralization by alkaline dust (calcareous and other mineral dust). When Ca is low, the acidity (mainly nitric acid) has a fairly constant background level throughout the cycle, with slightly lower values in ice believed to be from the last interglacial. Ca has to rise only slightly to neutralize the available acidity, so that acidity is a highly nonlinear reflection of climate changes. If neutralization occurred in the aerosol (rather than in the ice), then the number of cloud condensation nuclei over parts of the northern hemisphere could have been reduced, leading to reduced cloud albedo. This nonlinear feedback may have some importance for modeling of climate change. When both acid and ammonium levels are low, the DEP signal can be used to give a rapid indication of chloride trends

    Entwicklung eines zeitlichen und räumlichen Entscheidungshilfesystems gegen den Erbsenwickler (Cydia nigricana, Fabricius)

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    Pea moths (Cydia nigricana) can cause severe damages in pea crops (Pisum sativum). Larvae feed on the seeds in the pods and contaminate them with feces. In the cultivation of organic green peas 0.5 % damaged seeds lead to the denial of whole pea fields (Schulz & Saucke 2005). There can be a yield loss in forage peas and a loss of quality of seeds for propagation. Within the framework of the project to improve the spatial and temporal cultivation strategy of peas to get less damage due to pea moths, is the intention. For a better spatial and temporal cultivation strategy, the DSS creates a map with areas with an infestation risk factor. The higher the risk factor, the earlier the new fields should be cultivated. Therefore, the first part of the DSS works with georeferenced data, like distances between fields of the previous year and the currently planned fields and their infestation risk. The coincidence of the flowering of peas and the flight of pea moths is very important for the infestation. Hence, the second part of the DSS predicts the phenology of the pea and the development of the pea moth for a better precision of the pest control

    Erbsenwickler (Cydia nigricana) in Gemüse- und Körnererbsen: Grundlagen zur Befallsprognose und Schadensprävention

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    Spatio-temporal distribution, combined with aspects of insect biology and ecology can influence the infestation risk of the key pea pest Cydia nigricana in vegetable- and field peas. The proximity of pea fields of the previous cultivation period highly affects the infestation potential of the moth. The presented study aims to monitor the infestation development in three different regions in Germany (North Hesse, Saxony, Saxony-Anhalt) in four consecutive years and to relate empirical pest incidences to key factors as crop abundance, the distance to previous pea fields, the pea plant phenology and climatic conditions. In a next step, these data will form the basis for the elaboration of a computer-aided decision support system, which assists farmers in implementing preventive strategies based on risk avoidance

    Antiproton-nucleus electromagnetic annihilation as a way to access the proton timelike form factors

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    Contrary to the reaction pbar + p --> e+ e- with a high momentum incident antiproton on a free target proton at rest, in which the invariant mass M of the (e+ e-) pair is necessarily much larger than the (pbar p) mass, in the reaction pbar + d --> n e+ e- the value of M can take values near or below the (pbar p) mass. In the antiproton-deuteron electromagnetic annihilation, this allows to access the proton electromagnetic form factors in the time-like region of q^2 near the (pbar p) threshold. We estimate the cross section dsigma(pbar +d --> e+ e- n)/dM for an antiproton beam momentum of 1.5 GeV/c. We find that near the (pbar p) threshold this cross section is about 1 pb/MeV. The case of heavy nuclei target is also discussed. Elements of experimental feasibility are presented for the process pbar + d --> n e+ e- in the context of the Panda project.Comment: 14 pages, 11 figures. submitted to EPJ
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