196 research outputs found
Analysis of polyaniline oligomers by laser desorption ionization and solventless MALDI
AbstractWhile direct laser desorption ionization of soluble polyaniline dried onto metal sample plates results in mass spectra that are similar to previously shown electrospray ionization data of similar samples, laser desorption of unsolubilized solid polyaniline results in major fragmentation of the phenyl rings. Solventless MALDI, a recently developed technique for insoluble or slightly soluble species, involves the use of only solid analyte and matrix during sample preparation. Solventless MALDI of solid polyaniline results in mass spectra that are similar to the direct laser desorption ionization spectra of the soluble oligomers with some larger molecular weight oligomers also being detected. Based on the matrix used, different series of polyaniline with dissimilar end groups are detected. The matrix also affects the percentages of benzenoid and quinoid units in the oligomers. Thus, solventless MALDI appears to be a promising new technique for the mass spectrometric analysis of low solubility, but industrially important, polyanilines
Fermion scattering by a Schwarzschild black hole
We study the scattering of massive spin-half waves by a Schwarzschild black
hole using analytical and numerical methods. We begin by extending a recent
perturbation theory calculation to next order to obtain Born series for the
differential cross section and Mott polarization, valid at small couplings. We
continue by deriving an approximation for glory scattering of massive spinor
particles by considering classical timelike geodesics and spin precession.
Next, we formulate the Dirac equation on a black hole background, and outline a
simple numerical method for finding partial wave series solutions. Finally, we
present our numerical calculations of absorption and scattering cross sections
and polarization, and compare with theoretical expectations.Comment: Minor changes, 1 figure added. Version to appear in Phys. Rev. D. 36
pages, 13 figure
Measuring the Core Components of Maladaptive Personality: Severity Indices of Personality Problems (SIPP-118)
This report describes a series of studies among 2231 subjects on the development of the Severity Indices for Personality Problems (SIPP), a self-report questionnaire measuring the core components of (mal)adaptive personality functioning. Results show that the 16 facets have good psychometric properties and test-retest reliability, are generic across various types of personality disorders, and have good discriminative validity between various populations. The facets fit well into a common factor model with five higher-order domains (i.e., self-control, identity integration, responsibility, relational capacities, and social concordance) that are eminently interpretable, and replicable across various populations. Domain scorThis report is the first document to describe the development of the SIPP-118: Severity Indices of Personality Problems, 118 items. It provides details about the items selection, validations and reliability studies and norm values. The report is meant as a detailed description of our investigation and is made directly after the data collection in order to allow for fast communication between researchers.
Although the report will probably remain the most detailed description of our research effort, it must not be seen as the final interpretation of the results. The report now serves as an easy accessible collection of research data, on which basis we hope to write peer-reviewed articles. This original report will remain available on request, for those researchers who would like to have a detailed description of the research and the data. Note that parts of the report still reveal the early thoughts and interpretations, which are characteristic for a first report written just after finishing the data collection.
Up-to-date information, norm scores, and translations of the SIPP-118 in Dutch, English, Norwegian, Argentinean, and Italian language, are freely available at www.vispd.nl
Economic evaluation of complete revascularization for patients with multivessel disease undergoing primary percutaneous coronary intervention
Objective: To determine the cost-effectiveness of complete revascularisation at index admission compared to infarct-related artery (IRA) treatment only, in patients with multi-vessel disease undergoing Primary percutaneous coronary intervention (P-PCI) for ST-segment elevation Myocardial Infarction (STEMI). Methods: Economic evaluation of a multi-centre randomised trial comparing complete revascularisation at index admission to IRA-only P-PCI in patients with multi-vessel disease (12 month follow-up). Overall hospital costs (costs for P-PCI procedure(s), hospital stay and any subsequent readmissions) were estimated. Outcomes were major adverse cardiac events (MACE, a composite of all-cause death, recurrent myocardial infarction, heart failure, and ischemia-driven revascularisation) and quality-adjusted life years (QALYs) derived from the EQ-5D-3L. Multiple imputation was undertaken. The mean incremental cost and effects, with associated 95% confidence intervals (95%CI), the incremental cost-effectiveness ratio (ICER) and the cost-effectiveness acceptability curve (CEAC) were estimated. Results: Based on 296 patients, the mean incremental overall hospital cost for complete revascularisation was estimated to be –£215.96 (–£1,390.20 to £958.29), compared to IRA-only, with a per-patient mean reduction in MACE events of 0.170 (0.044 to 0.296) and a QALY gain of 0.011 (-0.019 to 0.041). According to the CEAC, the probability of complete revascularisation being cost-effective was estimated to be 72.0% at willingness to pay of £20,000 per QALY. Conclusions: Complete revascularisation at index admission was estimated to be more effective (in terms of MACE and QALYs) and cost-effective (overall costs were estimated to be lower and complete revascularisation thereby dominated IRA-only). There was, however, some uncertainty associated with this decision
Electroweak Phase Transition in Two Higgs Doublet Models
We reexamine the strength of the first order phase transition in the
electroweak theory supplemented by an extra Higgs doublet. The
finite-temperature effective potential, , is computed to one-loop
order, including the summation of ring diagrams, to study the ratio
of the Higgs field VEV to the critical temperature. We make a
number of improvements over previous treatments, including a consistent
treatment of Goldstone bosons in , an accurate analytic approximation
to valid for any mass-to-temperature ratios, and use of the
experimentally measured top quark mass. For two-Higgs doublet models, we
identify a significant region of parameter space where is large
enough for electroweak baryogenesis, and we argue that this identification
should persist even at higher orders in perturbation theory. In the case of the
minimal supersymmetric standard model, our results indicate that the extra
Higgs bosons have little effect on the strength of the phase transition.Comment: 18 pp., 5 figures, uses epsf.tex. Corrected matching conditions for
analytic approximation to thermal effective potential, eq. (10), and typos in
eq. (5
Allelic polymorphism in the T cell receptor and its impact on immune responses
In comparison to human leukocyte antigen (HLA) polymorphism, the impact of allelic sequence variation within T cell receptor (TCR) loci is much less understood. Particular TCR loci have been associated with autoimmunity, but the molecular basis for this phenomenon is undefined. We examined the T cell response to an HLA-B*3501-restricted epitope (HPVGEADYFEY) from Epstein-Barr virus (EBV), which is frequently dominated by a TRBV9*01 public TCR (TK3). However, the common allelic variant TRBV9*02, which differs by a single amino acid near the CDR2β loop (Gln55→His55), was never used in this response. The structure of the TK3 TCR, its allelic variant, and a nonnaturally occurring mutant (Gln55→Ala55) in complex with HLA-B*3501 revealed that the Gln55→His55 polymorphism affected the charge complementarity at the TCR-peptide-MHC interface, resulting in reduced functional recognition of the cognate and naturally occurring variants of this EBV peptide. Thus, polymorphism in the TCR loci may contribute toward variability in immune responses and the outcome of infection
Erwartungsbildung über den Wahlausgang und ihr Einfluss auf die Wahlentscheidung
Erwartungen über den Wahlausgang haben einen festen Platz sowohl in Rational-Choice-Theorien des Wählerverhaltens als auch in stärker sozialpsychologisch orientierten Ansätzen. Die Bildung von Erwartungen und ihr Einfluss auf die Wahlentscheidung ist dabei jedoch ein noch relativ unerforschtes Gebiet. In diesem Beitrag werden anhand von Wahlstudien für Belgien, Österreich und Deutschland verschiedene Fragen der Erwartungsbildung und ihrer Auswirkungen untersucht. Zunächst wird die Qualität der Gesamterwartungen analysiert und verschiedene Faktoren identifiziert, die einen systematischen Einfluss auf die Erwartungsbildung haben. Im zweiten Schritt wenden wir uns den Einzelerwartungen über verschiedene Parteien und Koalitionen zu und finden eine moderate Verzerrung zugunsten der präferierten Parteien und Koalitionen. Dabei kann gezeigt werden, dass der Effekt des Wunschdenkens mit dem politischen Wissen und dem Bildungsgrad abnimmt. Schließlich werden in einem letzten Schritt zwei unterschiedliche Logiken für die Auswirkungen von Erwartungen getestet, das rationale Kalkül des koalitionsstrategischen Wählens zur Vermeidung der Stimmenvergeudung sowie der sozialpsychologisch begründete Bandwagon-Effekt. Das Ausmaß an politischem Wissen scheint dabei eine zentrale vermittelnde Variable zwischen den beiden Logiken zu sein
A qualitative meta-synthesis of interpersonal violence prevention programs focused on males
Exceptionally high levels of interpersonal violence have triggered a call by many experts for the need to determine effective ways to address the onset and effects of exposure to interpersonal violence. The specific aim of this study was to identify and draw on existing promising practices to make a more informed decision on strategies to develop a contextually relevant intervention that focused on the promotion of positive forms of masculinity to create safety and peace. This study used a qualitative meta-synthesis (QMS) technique to integrate and interpret findings from various intervention studies that focused on males and/or gender. An in-depth literature search yielded a total of 827 papers that met the search criteria. After removal of duplicates, abstract review, and review of the full texts, the subsequent sample for this meta-synthesis included 12 intervention programs and 23 studies. This QMS revealed the value of a comprehensive approach, using multiple strategies, employing participatory and interactive methods, and promoting social mobilization to address interpersonal violence. The promotion of positive forms of masculinity as an interpersonal violence prevention strategy is a much-needed, relatively untapped approach to generating safety and peace for both males and females
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