A Massive S-duality in 4 dimensions

We reduce the Type IIA supergravity theory with a generalized Scherk-Schwarz ansatz that exploits the scaling symmetry of the dilaton, the metric and the NS 2-form field. The resulting theory is a new massive, gauged supergravity theory in four dimensions with a massive 2-form field and a massive 1-form field. We show that this theory is S-dual to a theory with a massive vector field and a massive 2-form field, which are dual to the massive 2-form and 1-form fields in the original theory, respectively. The S-dual theory is shown to arise from a Scherk-Schwarz reduction of the heterotic theory. Hence we establish a massive, S-duality type relation between the IIA theory and the heterotic theory in four dimensions. We also show that the Lagrangian for the new four dimensional theory can be put in the most general form of a D=4, N=4 gauged Lagrangian found by Schon and Weidner, in which (part of) the SL(2) group has been gauged.Comment: 20 pages, references adde

The role of peer meetings for professional development in health science education: a qualitative analysis of reflective essays

Introduction The development of professional behaviour is an important objective for students in Health Sciences, with reflective skills being a basic condition for this development. Literature describes a variety of methods giving students opportunities and encouragement for reflection. Although the literature states that learning and working together in peer meetings fosters reflection, these findings are based on experienced professionals. We do not know whether participation in peer meetings also makes a positive contribution to the learning experiences of undergraduate students in terms of reflection. Aim The aim of this study is to gain an understanding of the role of peer meetings in students’ learning experiences regarding reflection. Method A phenomenographic qualitative study was undertaken. Students’ learning experiences in peer meetings were analyzed by investigating the learning reports in students’ portfolios. Data were coded using open coding. Results The results indicate that peer meetings created an interactive learning environment in which students learned about themselves, their skills and their abilities as novice professionals. Students also mentioned conditions for a well-functioning group. Conclusion The findings indicate that peer meetings foster the development of reflection skills as part of professional behaviour

Coulomb-blockade transport in single-crystal organic thin-film transistors

Coulomb-blockade transport—whereby the Coulomb interaction between electrons can prohibit their transport around a circuit—occurs in systems in which both the tunnel resistance, RT, between neighbouring sites is large (»h/e2) and the charging energy, EC (EC = e2/2C, where C is the capacitance of the site), of an excess electron on a site is large compared to kT. (Here e is the charge of an electron, k is Boltzmann's constant, and h is Planck's constant.) The nature of the individual sites—metallic, superconducting, semiconducting or quantum dot—is to first order irrelevant for this phenomenon to be observed. Coulomb blockade has also been observed in two-dimensional arrays of normal-metal tunnel junctions, but the relatively large capacitances of these micrometre-sized metal islands results in a small charging energy, and so the effect can be seen only at extremely low temperatures. Here we demonstrate that organic thin-film transistors based on highly ordered molecular materials can, to first order, also be considered as an array of sites separated by tunnel resistances. And as a result of the sub-nanometre sizes of the sites (the individual molecules), and hence their small capacitances, the charging energy dominates at room temperature. Conductivity measurements as a function of both gate bias and temperature reveal the presence of thermally activated transport, consistent with the conventional model of Coulomb blockade.

Shot noise in mesoscopic systems

This is a review of shot noise, the time-dependent fluctuations in the electrical current due to the discreteness of the electron charge, in small conductors. The shot-noise power can be smaller than that of a Poisson process as a result of correlations in the electron transmission imposed by the Pauli principle. This suppression takes on simple universal values in a symmetric double-barrier junction (suppression factor 1/2), a disordered metal (factor 1/3), and a chaotic cavity (factor 1/4). Loss of phase coherence has no effect on this shot-noise suppression, while thermalization of the electrons due to electron-electron scattering increases the shot noise slightly. Sub-Poissonian shot noise has been observed experimentally. So far unobserved phenomena involve the interplay of shot noise with the Aharonov-Bohm effect, Andreev reflection, and the fractional quantum Hall effect.Comment: 37 pages, Latex, 10 figures (eps). To be published in "Mesoscopic Electron Transport," edited by L. P. Kouwenhoven, G. Schoen, and L. L. Sohn, NATO ASI Series E (Kluwer Academic Publishing, Dordrecht

Development and evaluation of a cancer-related fatigue patient education program: protocol of a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Cancer-related fatigue (CRF) and its impact on patients' quality of life has been an increasing subject of research. However, in Germany there is a lack of evidence-based interventions consistent with the multidimensional character of fatigue. The objective of this study is to develop and evaluate a self-management program for disease-free cancer patients to cope with CRF.</p> <p>Methods</p> <p>Based on evidence extracted from a literature review, a curriculum for the self-management program was elaborated. The curriculum was reviewed and validated by an interdisciplinary expert group and the training-modules will be pretested with a small number of participants and discussed in terms of feasibility and acceptance.</p> <p>To determine the efficacy of the program a randomised controlled trial will be carried out: 300 patients will be recruited from oncological practices in Bremen, Germany, and will be allocated to intervention or control group. The intervention group participates in the program, whereas the control group receives standard care and the opportunity to take part in the program after the end of the follow-up (waiting control group). Primary outcome measure is the level of fatigue, secondary outcome measures are quality of life, depression, anxiety, self-efficacy and physical activity. Data will be collected before randomisation, after intervention, and after a follow-up of 6 months.</p> <p>Discussion</p> <p>Because there are no comparable self-management programs for cancer survivors with fatigue, the development of the curriculum has been complex; therefore, the critical appraisal by the experts was an important step to validate the program and their contributions have been integrated into the curriculum. The experts appreciated the program as filling a gap in outpatient cancer care.</p> <p>If the results of the evaluation prove to be satisfactory, the outpatient care of cancer patients can be broadened and supplemented.</p> <p>Trial Registration</p> <p>ClinicalTrials NCT00552552</p

Inter-organizational governance and trilateral trust building: a case study of crowdsourcing-based open innovation in China

In a case study of a Chinese crowdsourcing intermediary, we explore the impact of inter-organizational governance on trilateral trust-building. We show that formal control and relational governance mechanisms are essential for swift and knowledge-based trust in R&D crowdsourcing. The case also indicates that Chinese businesses continue to use guanxi (informal personal connections) as a relational and contingent mechanism to maintain affect-based trust, but guanxi is shown to inhibit the growth of Internet-based crowdsourcing for open innovation in China

Evolutionary Origin and Phylogeography of the Diploid Obligate Parthenogen Artemia parthenogenetica (Branchiopoda: Anostraca)

Background: Understanding the evolutionary origin and the phylogeographic patterns of asexual taxa can shed light on the origin and maintenance of sexual reproduction. We assessed the geographic origin, genetic diversity, and phylogeographic history of obligate parthenogen diploid Artemia parthenogenetica populations, a widespread halophilic crustaceanPeer reviewe

Dissecting Genetic Networks Underlying Complex Phenotypes: The Theoretical Framework

Great progress has been made in genetic dissection of quantitative trait variation during the past two decades, but many studies still reveal only a small fraction of quantitative trait loci (QTLs), and epistasis remains elusive. We integrate contemporary knowledge of signal transduction pathways with principles of quantitative and population genetics to characterize genetic networks underlying complex traits, using a model founded upon one-way functional dependency of downstream genes on upstream regulators (the principle of hierarchy) and mutual functional dependency among related genes (functional genetic units, FGU). Both simulated and real data suggest that complementary epistasis contributes greatly to quantitative trait variation, and obscures the phenotypic effects of many ‘downstream’ loci in pathways. The mathematical relationships between the main effects and epistatic effects of genes acting at different levels of signaling pathways were established using the quantitative and population genetic parameters. Both loss of function and “co-adapted” gene complexes formed by multiple alleles with differentiated functions (effects) are predicted to be frequent types of allelic diversity at loci that contribute to the genetic variation of complex traits in populations. Downstream FGUs appear to be more vulnerable to loss of function than their upstream regulators, but this vulnerability is apparently compensated by different FGUs of similar functions. Other predictions from the model may account for puzzling results regarding responses to selection, genotype by environment interaction, and the genetic basis of heterosis