169 research outputs found

    Can the Couplings in the Fermion-Higgs Sector of the Standard Model be Strong?

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    We present results for the renormalized quartic self-coupling λR\lambda_R and the Yukawa coupling yRy_R in a lattice fermion-Higgs model with two SU(2)L_L doublets, mostly for large values of the bare couplings. One-component (`reduced') staggered fermions are used in a numerical simulation with the Hybrid Monte Carlo algorithm. The fermion and Higgs masses and the renormalized scalar field expectation value are computed on L324L^3 24 lattices, where LL ranges from 66 to 1616. In the scaling region these quantities are found to have a 1/L21/L^2 dependence, which is used to determine their values in the infinite volume limit. We then calculate the yRy_R and λR\lambda_R from their tree level definitions in terms of the masses and renormalized scalar field expectation value, extrapolated to infinite volume. The scalar field propagators can be described for momenta up to the cut-off by one fermion loop renormalized perturbation theory and the results for λR\lambda_R and yRy_R come out to be close to the tree level unitarity bounds. There are no signs that are in contradiction with the triviality of the Yukawa and quartic self-coupling.Comment: 36 pages + 12 postscript figures (appended), Amsterdam ITFA 92-23, HLRZ Juelich 92-58, UCSD/PTH 92-3

    Characterization of the metabolic shift between oxidative and fermentative growth in Saccharomyces cerevisiae by comparative (13)C flux analysis

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    BACKGROUND: One of the most fascinating properties of the biotechnologically important organism Saccharomyces cerevisiae is its ability to perform simultaneous respiration and fermentation at high growth rate even under fully aerobic conditions. In the present work, this Crabtree effect called phenomenon was investigated in detail by comparative (13)C metabolic flux analysis of S. cerevisiae growing under purely oxidative, respiro-fermentative and predominantly fermentative conditions. RESULTS: The metabolic shift from oxidative to fermentative growth was accompanied by complex changes of carbon flux throughout the whole central metabolism. This involved a flux redirection from the pentose phosphate pathway (PPP) towards glycolysis, an increased flux through pyruvate carboxylase, the fermentative pathways and malic enzyme, a flux decrease through the TCA cycle, and a partial relocation of alanine biosynthesis from the mitochondrion to the cytosol. S. cerevisiae exhibited a by-pass of pyruvate dehydrogenase in all physiological regimes. During oxidative growth this by-pass was mainly provided via pyruvate decarboxylase, acetaldehyde dehydrogenase, acetyl-CoA synthase and transport of acetyl-CoA into the mitochondrion. During fermentative growth this route, however, was saturated due to limited enzyme capacity. Under these conditions the cells exhibited high carbon flux through a chain of reactions involving pyruvate carboxylase, the oxaloacetate transporter and malic enzyme. During purely oxidative growth the PPP alone was sufficient to completely supply NADPH for anabolism. During fermentation, it provided only 60 % of the required NADPH. CONCLUSION: We conclude that, in order to overcome the limited capacity of pyruvate dehydrogenase, S. cerevisiae possesses different metabolic by-passes to channel carbon into the mitochondrion. This involves the conversion of cytosolic pyruvate either into acetyl CoA or oxaloacetate followed by intercompartmental transport of these metabolites. During oxidative growth mainly the NAD specific isoforms of acetaldehyde dehydrogenase and isocitrate dehydrogenase catalyze the corresponding reactions in S. cerevisiae, whereas NADPH supply under fermentative conditions involves significant contribution of sources other than the PPP such as e. g. NADPH specific acetaldehyde dehydrogenase or isocitrate dehydrogenase

    No strong coupling regime in the fermion-Higgs sector of the standard model

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    We present results for the renormalized quartic self-coupling \lm_R and the renormalized Yukawa coupling yRy_R in a fermion-Higgs model with two SU(2) doublets, indicating that these couplings are not very strong.Comment: 4 pages, 4 postscript figures (appended), ITFA-92-32, HLRZ-92-92, UCSD/PTH 92-43, Contribution to the Conference Lattice'9

    Automatisierte Linienplanung im öffentlichen Verkehr

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    Automatisierung und Digitalisierung sollen in der Bahnproduktion Kosten senken und die Kapazität der Infrastruktur erhöhen. Dazu müssen alle Planungsschritte in einem einheitlichen System abgebildet werden. Davon profitieren die Bahnkunden durch ein attraktiveres Angebot, höhere Pünktlichkeit und mehr Sicherheit. Die ZHAW beteiligt sich an dieser Entwicklung in Forschung und Lehre. Unter anderem wurde für den Schritt der Linienplanung eine Methode entworfen, die es erlaubt in kurzer Zeit kostenoptimale und kundenfreundliche Linienpläne zu erstellen

    Spiritual Dryness as a Measure of a Specific Spiritual Crisis in Catholic Priests: Associations with Symptoms of Burnout and Distress

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    Spirituality/religiosity is recognized as a resource to cope with burdening life events and chronic illness. However, less is known about the consequences of the lack of positive spiritual feelings. Spiritual dryness in clergy has been described as spiritual lethargy, a lack of vibrant spiritual encounter with God, and an absence of spiritual resources, such as spiritual renewal practices. To operationalize experiences of ``spiritual dryness'' in terms of a specific spiritual crisis, we have developed the ``spiritual dryness scale'' (SDS). Here, we describe the validation of the instrument which was applied among other standardized questionnaires in a sample of 425 Catholic priests who professionally care for the spiritual sake of others. Feelings of ``spiritual dryness'' were experienced occasionally by up to 40%, often or even regularly by up to 13%. These experiences can explain 44% of variance in daily spiritual experiences, 30% in depressive symptoms, 22% in perceived stress, 20% in emotional exhaustion, 19% in work engagement, and 21% of variance of ascribed importance of religious activity. The SDS-5 can be used as a specific measure of spiritual crisis with good reliability and validity in further studies

    Selection of peptide ligands binding to the basolateral cell surface of proximal convoluted tubules

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    Selection of peptide ligands binding to the basolateral cell surface of proximal convoluted tubules.BackgroundRecently, we have reported a novel approach of screening phage-display peptide libraries on microdissected intact renal tubular segments and identified an RGD-containing peptide ligand that specifically binds to the basolateral membrane of cortical collecting ducts (CCD). However, screening phage libraries on proximal convoluted tubules (PCT) did not yield a tubule segment-specific ligand. Here, we describe the successful modification of our previously developed phage-display approach and the identification of two distinct ligands that bind specifically to receptors expressed at the basolateral membrane of PCT.MethodsEx vivo screening of phage-display peptide libraries for specific ligands was adapted for PCT. The previously developed method was significantly extended by applying it to a distinct tubular segment, varying the number of rounds of biopanning and incubating phage libraries with absorber cells prior to biopanning. Binding specificity and cellular localization of selected peptide-displaying phage or the corresponding synthetic peptide were analyzed using various epithelial cell lines as well as competition assays and confocal immunofluorescence microscopy.ResultsScreening phage-display peptide libraries, depleted of ligands binding to ubiquitously expressed receptors by preincubation with HEK-293 cells, led to the identification of two PCT-specific ligands. Phage expressing peptides with the consensus sequence GV(K/R)GX3(T/S) or RDXR mediated 15-fold and 13-fold higher binding to PCT than control phage, and binding to PCT was 13-fold and 21-fold higher than binding to CCD, respectively. Neither phage mediated significant binding to various epithelial cell lines, and binding of both ligands was abolished by the addition of the corresponding synthetic peptide. Immunofluorescence experiments revealed a submembrane localization of both ligands upon incubation with PCT.ConclusionsExploiting the versatility of phage-display and biopanning allowed the identification of two distinct peptide ligands that bind specifically to the basolateral membrane of PCT. Tubule segment-specific ligands, such as the described PCT ligands, may be useful for the analysis of cell-extracellular matrix interactions and may contribute to the development of new therapeutic strategies for renal diseases

    Query Evaluation on Compressed Trees (Extended Abstract)

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    Nachnutzung der gemeinsamen JOIN2^2 –Repository-Infrastruktur für den KDSF-Objektbereich Publikation?

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    Im Rahmen des JOIN2-Projekts haben Bibliotheks- & Dokumentationseinheiten (Deutsches Elektronensynchrotron DESY Hamburg/Zeuten, Deutsches Krebsforschungszentrum DKFZ Heidelberg, Forschungszentrum Jülich, GSI Helmholtzzentrum für Schwerionenforschung Darmstadt, Maier-Leibnitz-Zentrum Garching, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen, KIT Institut für experimentelle Kernphysik Karlsruhe) eine gemeinsame Repository-Infrastruktur für ihre Wissenschaftler und Wissenschaftlerinnen geschaffen. Das Poster dokumentiert Überlegungen, welche Anforderungen des Kerndatensatzes Forschung im Objektbereich abgebildet werden können, wo Probleme und fehlende Normierungen in der Praxis auftauchen könnten und vor allem, an welchen Stellen Kompromisse in Hinblick auf die JOIN2-Serviceorientierung für den Wissenschaftsbereich eingegangen werden müssen.Schlagwörter: Repositorium; VeröffentlichungsdatenbankSchwerpunktbereich: Identifikatoren & Anbindung von Drittsystemen, z.B. von Repositorie

    Features of informatization of education in Poland and Ukraine

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    У тезах описуються пріоритети політики ЄС у сфері інформатизації освіти в контексті реалізації програми «Освіта та професійна підготовка 2020» за прикладом Польщі. Розглядаються стратегічні європейські документи щодо інформатизації освіти, розвитку цифрових компетентностей і переходу до відкритої освіти. Окреслено інфраструктуру розвитку дистанційної освіти у Республіці Польща.The theses describe the priorities of EU policy in the field of informatization of education in the context of the implementation of the program "Education and Training 2020", for example in Poland. The strategic European documents concerning informatization of education, development of digital competences and transition to open education are considered. The infrastructure of development of distance education in the Republic of Poland is outlined
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