92 research outputs found
1/m_b^2 correction to the left-right lepton polarization asymmetry in the decay B -> X_s mu^+ mu^-
Using a known result by Falk et al. for the 1/m_b^2 correction to the
dilepton invariant mass spectrum in the decay B \rightarrow X_s \mu^+ \mu^-, we
calculate the 1/m_b^2 correction to the left-right muon polarization asymmetry
in this decay. Employing an up-to-date range of values for the non-perturbative
parameter \lambda_1, we find that the correction is much smaller than it should
have been expected from the previous work by Falk et al.Comment: 8 pages, 2 figures included. Uses epsf.sty and rotate.sty. To appear
in Physical Review D. The complete postscript file is also available from URL
ftp://feynman.t30.physik.tu-muenchen.de/pub/preprints/ tum_t31_98_96.ps.g
Global value chains and human development: a class-relational framework
Global Value Chain proponents argue that regional and human development can be achieved through âstrategic couplingâ with transnational corporations. This argument is misleading for two reasons. First, GVC abstracts firm-firm and firm-state relations from their class-relational basis, obscuring fundamental developmental processes. Second, much GVC analysis promotes linear conceptions of development. This article provides a class-relational framework for GVC analysis. The formation and functioning of GVCs and the developmental effects associated with them are products of histories of evolving and often conflictive, class relations. A study of export horticulture in North East Brazil provides empirical support for these arguments
Two photon decays of heavy vector mesons, ,, and the possible determination of the and couplings
We study the novel decays and using the framework of the Heavy Meson Chiral Lagrangian (HML)
to leading order in chiral perturbation theory. The branching ratios of these
decays are expressed in terms of the strong and the
electromagnetic couplings, thus providing a possible
tool for their determination. In the charm case, using the experimentally
determined ratios we are able
to express the branching ratio as a function of the strong coupling only. We
thus find for where is the strong
coupling of HML. In the beauty sector, the which we estimate to be in the range is a
function of both and Its behaviour does not
afford an unambiguous determination of these couplings except for the region of
high values like The expected two-photon differential
distributions are presented for both and
for different values of the couplings
involved.Comment: 22 pages, LaTeX, 5 ps-figures (uses subfigure.sty). Accepted by Phys.
Rev.
Accounting for Equity Considerations in Cost-Effectiveness Analysis : A Systematic Review of Rotavirus Vaccine in Low- and Middle-Income Countries
Additional file 3: Appendix C. Full data table of results
Cadophora margaritata sp. nov. and other fungi associated with the longhorn beetles Anoplophora glabripennis and Saperda carcharias in Finland
Symbiosis with microbes is crucial for survival and development of wood-inhabiting longhorn beetles (Coleoptera: Cerambycidae). Thus, knowledge of the endemic fungal associates of insects would facilitate risk assessment in cases where a new invasive pest occupies the same ecological niche. However, the diversity of fungi associated with insects remains poorly understood. The aim of this study was to investigate fungi associated with the native large poplar longhorn beetle (Saperda carcharias) and the recently introduced Asian longhorn beetle (Anoplophora glabripennis) infesting hardwood trees in Finland. We studied the cultivable fungal associates obtained from Populus tremula colonised by S. carcharias, and Betula pendula and Salix caprea infested by A. glabripennis, and compared these to the samples collected from intact wood material. This study detected a number of plant pathogenic and saprotrophic fungi, and species with known potential for enzymatic degradation of wood components. Phylogenetic analyses of the most commonly encountered fungi isolated from the longhorn beetles revealed an association with fungi residing in the Cadophora-Mollisia species complex. A commonly encountered fungus was Cadophora spadicis, a recently described fungus associated with wood-decay. In addition, a novel species of Cadophora, for which the name Cadophora margaritata sp. nov. is provided, was isolated from the colonised wood.Peer reviewe
Usersâ design feedback in usability evaluation: a literature review
Abstract As part of usability evaluation, users may be invited to offer their reflections on the system being evaluated. Such reflections may concern the systemâs suitability for its context of use, usability problem predictions, and design suggestions. We term the data resulting from such reflections usersâ design feedback. Gathering usersâ design feedback as part of usability evaluation may be seen as controversial, and the current knowledge on usersâ design feedback is fragmented. To mitigate this, we have conducted a literature review. The review provides an overview of the benefits and limitations of usersâ design feedback in usability evaluations. Following an extensive search process, 31 research papers were identified as relevant and analysed. Usersâ design feedback is gathered for a number of distinct purposes: to support budget approaches to usability testing, to expand on interaction data from usability testing, to provide insight into usability problems in usersâ everyday context, and to benefit from usersâ knowledge and creativity. Evaluation findings based on usersâ design feedback can be qualitatively different from, and hence complement, findings based on other types of evaluation data. Furthermore, findings based on usersâ design feedback can hold acceptable validity, though the thoroughness of such findings may be questioned. Finally, findings from usersâ design feedback may have substantial impact in the downstream development process. Four practical implications are highlighted, and three directions for future research are suggested
Disorders of Consciousness
Disorders of Consciousness are a big challenge for the entire process of rehabilitation: assessment, diagnosis, pharmacological, and rehabilitation programs, including conventional treatments and the use of new technologies
A Prototype Representation to Approximate White Matter Bundles with Weighted Currents
International audienceQuantitative and qualitative analysis of white matter fibers resulting from tractography algorithms is made difficult by their huge number. To this end, we propose an \textit{approximation scheme} which gives as result a more concise but at the same time exhaustive representation of a fiber bundle. It is based on a novel computational model for fibers, called \textit{weighted currents}, characterised by a metric that considers both the pathway and the anatomical locations of the endpoints of the fibers. Similarity has therefore a twofold connotation: geometrical and related to the connectivity. The core idea is to use this metric for approximating a fiber bundle with a set of weighted prototypes, chosen among the fibers, which represent ensembles of similar fibers. The weights are related to the number of fibers represented by the prototypes. The algorithm is divided into two steps. First, the main modes of the fiber bundle are detected using a \textit{modularity based clustering} algorithm. Second, a \textit{prototype fiber selection} process is carried on in each cluster separately. This permits to explain the main patterns of the fiber bundle in a fast and accurate way
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