298 research outputs found
Constraints on Parity-Even Time Reversal Violation in the Nucleon-Nucleon System and Its Connection to Charge Symmetry Breaking
Parity-even time reversal violation (TRV) in the nucleon-nucleon interaction
is reconsidered. The TRV -exchange interaction on which recent analyses
of measurements are based is necessarily also charge-symmetry breaking (CSB).
Limits on its strength relative to regular -exchange are
extracted from recent CSB experiments in neutron-proton scattering. The result
(95% CL) is considerably lower than limits
inferred from direct TRV tests in nuclear processes. Properties of
-exchange and limit imposed by the neutron EDM are briefly discussed.Comment: RevTex, 8 pages. Factor ten error in cited neutron EDM corrected,
discussion and two references adde
Constraints on a Parity-Conserving/Time-Reversal-Non-Conserving Interaction
Time-Reversal-Invariance non-conservation has now been unequivocally
demonstrated in a direct measurement at CPLEAR. What about tests of
time-reversal-invariance in systems other than the kaon system? Tests of
time-reversal-invariance belong to two classes: searches for parity violating
(P-odd)/time-reversal-invariance-odd (T-odd) interactions, and for P-even/T-odd
interactions (assuming CPT conservation this implies C-conjugation
non-conservation). Limits on a P-odd/T-odd interaction follow from measurements
of the electric dipole moment of the neutron (with a present upper limit of 6 x
10^-26 e.cm [95% C.L.]). It provides a limit on a P-odd/T-odd pion-nucleon
coupling constant which is less than 10^-4 times the weak interaction strength.
Experimental limits on a P-even/T-odd interaction are much less stringent.
Following the standard approach of describing the nucleon-nucleon interaction
in terms of meson exchanges, it can be shown that only charged rho-meson
exchange and A_1 meson exchange can lead to a P-even/T-odd interaction. The
better constraints stem from measurements of the electric dipole moment of the
neutron and from measurements of charge-symmetry breaking in neutron-proton
elastic scattering. The latter experiments were executed at TRIUMF (497 and 347
MeV) and at IUCF (183 MeV). Weak decay experiments may provide limits which
will possibly be comparable. All other experiments, like gamma decay
experiments, detailed balance experiments, polarization - analyzing power
difference determinations, and five-fold correlation experiments with polarized
incident nucleons and aligned nuclear targets, have been shown to be at least
an order of magnitude less sensitive.Comment: 15 pages LaTeX, including 5 PostScript figures. Uses ijmpe1.sty. To
appear in International Journal of Modern Physics E (IJMPE). Slight change in
short abstrac
Off-Shell Rho-Omega Mixing Through Quark Loops With Non-Perturbative Meson Vertex And Quark Mass Functions
The momemtum dependence of the off-shell - mixing amplitude is
calculated through a two-quark loop diagram, using non-perturbative meson-quark
vertex functions for the and mesons, as well as
non-perturbative quark propagators. Both these quantities are generated
self-consistently through an interlinked BSE-cum-SDE approach with a 3D support
for the BSE kernel with two basic constants which are pre- checked against a
wide cross section of both meson and baryon spectra within a common structural
framework for their respective 3D BSE's. With this pre-calibration, the
on-shell strength works out at -2.434 in units of the change in
"constituent mass squared", which is consistent with the to
data for a u-d mass difference of ~4 MeV ,while the relative
off-shell strength (0.99 0.01) lies midway between quark-loop and QCD-SR
results. We also calculate the photon-mediated - propagator whose
off-shell structure has an additional pole at =0. The implications of
these results vis-a-vis related investigations are discussed.Comment: 12 Pages, latex file, NTUTH-94-0
How the recent BABAR data for P to \gamma\gamma* affect the Standard Model predictions for the rare decays P to l+l-
Measuring the lepton anomalous magnetic moments and the rare decays
of light pseudoscalar mesons into lepton pairs , serve as
important tests of the Standard Model. To reduce the theoretical uncertainty in
the standard model predictions, the data on the charge and transition form
factors of the light pseudoscalar mesons play a significant role. Recently, new
data on the behavior of the transition form factors at
large momentum transfer were supplied by the BABAR collaboration. There are
several problems with the theoretical interpretation of these data: 1) An
unexpectedly slow decrease of the pion transition form factor at high momenta,
2) the qualitative difference in the behavior of the pion form factor and the
and form factors at high momenta, 3) the inconsistency of
the measured ratio of the and form factors with the
predicted one. We comment on the influence of the new BABAR data on the rare
decay branchings.Comment: 11 pages, 3 figure
Umsetzung der Energiestrategie 2050 - Band II : Neue Ansätze für Staat und Wirtschaft
In diesem, dem zweiten Band von "Energy Governance" befassen sich die Autoren aus vielfältiger Perspektive mit zahlreichen Fragen zur Umsetzung der Energiestrategie 2050. Sie identifizieren jene Fälle von Solaranlagen, bei denen der Ersatz einer Baubewilligung zu Rechtsunsicherheit führt. Sie untersuchen die Wirkung moderner Finanzberichterstattung auf die Politik der kantonalen Beteiligungen an Energieversorgungsunternehmen in einer Marktumgebung tiefer Strompreis. Analysiert wird weiter die staatliche Förderung der erneuerbaren Stromproduktion im Hinblick auf ihre Wirkung. Eine kritische Analyse der "Smart City"-Projekte in der Schweiz und in den Nachbarländern Deutschland und Österreich führt zu Empfehlungen, wie solche Projekte effizienter geplant und umgesetzt werden können. Auch die Beziehung öffentlicher Organisationen zu ihrer "Stakeholder-Umwelt" wird behandelt
Umsetzung der Energiestrategie 2050: Herausforderungen und Chancen für Staat und Wirtschaft
Sammelband der Reihe "Energy Governance Working Paper" Nr. 1 bis 7Die Energiestrategie 2050 des Bundes definiert anspruchsvolle Ziele. Für deren Erreichung hat der Bundesrat daher unter anderem den Aktionsplan Energieforschung ins Leben gerufen. Dazu wurden acht sogenannte SCCERs, Swiss Competence Center for Energy Research, initiiert, in denen hochschulübergreifend angewandte Energie-Forschung betrieben wird. Die Zürcher Hochschule für Angewandte Wissenschaften (ZHAW) ist an vier dieser acht SCCERs aktiv beteiligt.
Die ZHAW hat diese Aufgabe zum Anlass genommen, Energieforschung zum strategischen Schwerpunkt der gesamten Fachhochschule zu erklären und in allen Departementen Kompetenzaufbauprojekte zu starten. Der vorliegende Sammelband präsentiert die ersten Ergebnisse dieser Kompetenzaufbauprojekte an der School of Management and Law, wobei zwei dieser Projekte in Zusammenarbeit mit Forschern aus den Departementen Angewandte Linguistik und School of Engineering erfolgten. Dabei wurden die Herausforderungen und Chancen, die sich für Staat und Wirtschaft aus der Umsetzung der Energiestrategie 2050 ableiten, auf verschiedenen Ebenen betrachtet: die Schweiz im internationalen Vergleich, Besonderheiten der Führung von EVUs, rechtliche und ökonomische Rahmenbedingungen und die Gestaltung der Energie-Zukunft in Schweizer Städten
Report and preliminary results of R/V SONNE Cruise SO251 - Extreme events Archived in the GEologial Record of JAPAN's subduction margins (EAGER-JAPAN)
Leg A SO251-1, Yokohama - Yokohama, 04.10.2016 - 15.10.2016, Leg B SO251-2, Yokohama - Yokohama, 18.10.2016 - 02.11.201
A protein functionalization platform based on selective reactions at methionine residues.
Nature has a remarkable ability to carry out site-selective post-translational modification of proteins, therefore enabling a marked increase in their functional diversity1. Inspired by this, chemical tools have been developed for the synthetic manipulation of protein structure and function, and have become essential to the continued advancement of chemical biology, molecular biology and medicine. However, the number of chemical transformations that are suitable for effective protein functionalization is limited, because the stringent demands inherent to biological systems preclude the applicability of many potential processes2. These chemical transformations often need to be selective at a single site on a protein, proceed with very fast reaction rates, operate under biologically ambient conditions and should provide homogeneous products with near-perfect conversion2-7. Although many bioconjugation methods exist at cysteine, lysine and tyrosine, a method targeting a less-explored amino acid would considerably expand the protein functionalization toolbox. Here we report the development of a multifaceted approach to protein functionalization based on chemoselective labelling at methionine residues. By exploiting the electrophilic reactivity of a bespoke hypervalent iodine reagent, the S-Me group in the side chain of methionine can be targeted. The bioconjugation reaction is fast, selective, operates at low-micromolar concentrations and is complementary to existing bioconjugation strategies. Moreover, it produces a protein conjugate that is itself a high-energy intermediate with reactive properties and can serve as a platform for the development of secondary, visible-light-mediated bioorthogonal protein functionalization processes. The merger of these approaches provides a versatile platform for the development of distinct transformations that deliver information-rich protein conjugates directly from the native biomacromolecules
Native diversity buffers against severity of non-native tree invasions
Determining the drivers of non-native plant invasions is critical for managing native ecosystems and limiting the spread of invasive species. Tree invasions in particular have been relatively overlooked, even though they have the potential to transform ecosystems and economies. Here, leveraging global tree databases, we explore how the phylogenetic and functional diversity of native tree communities, human pressure and the environment influence the establishment of non-native tree species and the subsequent invasion severity. We find that anthropogenic factors are key to predicting whether a location is invaded, but that invasion severity is underpinned by native diversity, with higher diversity predicting lower invasion severity. Temperature and precipitation emerge as strong predictors of invasion strategy, with non-native species invading successfully when they are similar to the native community in cold or dry extremes. Yet, despite the influence of these ecological forces in determining invasion strategy, we find evidence that these patterns can be obscured by human activity, with lower ecological signal in areas with higher proximity to shipping ports. Our global perspective of non-native tree invasion highlights that human drivers influence non-native tree presence, and that native phylogenetic and functional diversity have a critical role in the establishment and spread of subsequent invasions
N-Acetylcysteine and Allopurinol Synergistically Enhance Cardiac Adiponectin Content and Reduce Myocardial Reperfusion Injury in Diabetic Rats
Background: Hyperglycemia-induced oxidative stress plays a central role in the development of diabetic myocardial complications. Adiponectin (APN), an adipokine with anti-diabetic and anti-ischemic effects, is decreased in diabetes. It is unknown whether or not antioxidant treatment with N-acetylcysteine (NAC) and/or allopurinol (ALP) can attenuate APN deficiency and myocardial ischemia reperfusion (MI/R) injury in the early stage of diabetes. Methodology/Principal Findings: Control or streptozotocin (STZ)-induced diabetic rats were either untreated (C, D) or treated with NAC (1.5 g/kg/day) or ALP (100 mg/kg/day) or their combination for four weeks starting one week after STZ injection. Plasma and cardiac biochemical parameters were measured after the completion of treatment, and the rats were subjected to MI/R by occluding the left anterior descending artery for 30 min followed by 2 h reperfusion. Plasma and cardiac APN levels were decreased in diabetic rats accompanied by decreased cardiac APN receptor 2 (AdipoR2), reduced phosphorylation of Akt, signal transducer and activator of transcription 3 (STAT3) and endothelial nitric oxide synthase (eNOS) but increased IL-6 and TNF-α (all P<0.05 vs. C). NAC but not ALP increased cardiac APN concentrations and AdipoR2 expression in diabetic rats. ALP enhanced the effects of NAC in restoring cardiac AdipoR2 and phosphorylation of Akt, STAT3 and eNOS in diabetic rats. Further, NAC and ALP, respectively, decreased postischemic myocardial infarct size and creatinine kinase-MB (CK-MB) release in diabetic rats, while their combination conferred synergistic protective effects. In addition, exposure of cultured rat cardiomyocytes to high glucose resulted in significant reduction of cardiomyocyte APN concentration and AdipoR2 protein expression. APN supplementation restored high glucose induced AdipoR2 reduction in cardiomyocytes. Conclusions/Significance: NAC and ALP synergistically restore myocardial APN and AdipoR2 mediated eNOS activation. This may represent the mechanism through which NAC and ALP combination greatly reduces MI/R injury in early diabetic rats. © 2011 Wang et al.published_or_final_versio
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