F and D Values with Explicit Flavor Symmetry Breaking and \Delta s Contents of Nucleons

We propose a new model for describing baryon semi-leptonic decays for estimating $F$ and $D$ values with explicit breaking effects of both SU(3) and SU(2) flavor symmetry, where all possible SU(3) and SU(2) breaking effects are induced from an effective interaction. An overall fit including the weak magnetism form factor yields $F=0.477\pm 0.001$ and $D=0.835\pm 0.001$ with $\chi^2=4.43/5$ d.o.f. with $V_{ud}=0.975\pm 0.002$ and $V_{us}=0.221\pm 0.002$. The spin content of strange quarks $\Delta s$ is estimated from the obtained values $F$ and $D$, and the nucleon spin problem is re-examined. Furthermore, the unmeasured values of $(g_1/f_1)$ and $(g_1)$ for other hyperon semi-leptonic decays are predicted from this new formula.Comment: 15 pages, 1 figure, final version to appear in PR

Homophileurus neptunus Dechambre, a new junior synonym of H. waldenfelsi Endrödi (Coleoptera: Scarabaeidae: Dynastinae: Phileurini)

Homophileurus neptunus Dechambre was found to be conspecific with H. waldenfelsi Endrödi after examination of types, descriptions, and illustrations. Accordingly, H. neptunus is placed in junior synonymy with H. waldenfelsi, new synonymy. Homophileurus waldenfelsi is an uncommon species and occurs in Ecuador, Colombia, Brazil, and Peru. Brazil and Peru are new country records

Does the National Institute for Health and Clinical Excellence take account of factors such as uncertainty and equity as well as incremental cost-effectiveness in commissioning health care services? A binary choice experiment

Background: NICE is an independent organisation responsible for providing national guidance on the promotion of good health and the prevention and treatment of ill health in England and Wales. One of NICE’s main roles is to produce national guidance on the use of health technologies within the NHS. Despite the Institute’s recent efforts to clarify the way in which its Appraisal Committees reach their recommendations concerning the use of health technologies, there remains ambiguity about how cost-effectiveness evidence is interpreted alongside other considerations such as the degree of clinical need within the patient population, and the degree of uncertainty surrounding cost-effectiveness estimates. Objective: To explore whether the NICE takes account of factors such as uncertainty and equity as well as incremental cost-effectiveness in commissioning health care services. Methods: A binary choice experiment was undertaken using NICE’s three Appraisal Committees. The experiment included five attributes: (1) Incremental cost-effectiveness (2) Degree of economic uncertainty (3) Age of the target population (4) Baseline health-related quality of life (5) Availability of other therapies A choice questionnaire detailing 18 scenarios was administered to NICE’s Appraisal Committees. For each scenario, respondents were asked to indicate whether they would recommend the intervention under consideration or not. The stated preference data obtained from respondents were analysed using a random effects logit regression model. Results: A response rate of 46% was obtained from the Appraisal Committees. The regression model suggests that increases in cost-effectiveness, economic uncertainty, and the availability of other therapies are associated with statistically significant reductions in the odds of adoption (p<0.05). The transition from a very low to a comparatively high level of health-related quality of life is also associated with a statistically significant reduction in the odds of a positive recommendation. Smaller changes in health-related quality of life, and the age of the target population are not associated with a statistically significant reduction in the odds of a positive recommendation. Analysis of revealed preference data indicates that the model is capable of distinguishing between those technologies which the Appraisal Committees would be highly likely to recommend, and those technologies which appear to be less attractive, although further external validation is warranted. Conclusion: The modelling suggests that cost-effectiveness, uncertainty and certain equity concerns influence the NICE Appraisal Committees’ recommendations on the use of health technologies. The modelling results appear to support Rawlins and Culyer’s notion of a probabilistic cost-effectiveness threshold approach; the "mythical" £30,000 per QALY gained threshold assumed within the literature is not supported by this stated preference modelling analysis

Does the National Institute for Health and Clinical Excellence take account of factors such as uncertainty and equity as well as incremental cost-effectiveness in commissioning health care services? A binary choice experiment

Background NICE is an independent organisation responsible for providing national guidance on the promotion of good health and the prevention and treatment of ill health in England and Wales. One of NICE’s main roles is to produce national guidance on the use of health technologies within the NHS. Despite the Institute’s recent efforts to clarify the way in which its Appraisal Committees reach their recommendations concerning the use of health technologies, there remains ambiguity about how cost-effectiveness evidence is interpreted alongside other considerations such as the degree of clinical need within the patient population, and the degree of uncertainty surrounding cost-effectiveness estimates. Objective To explore whether the NICE takes account of factors such as uncertainty and equity as well as incremental cost-effectiveness in commissioning health care services. Methods A binary choice experiment was undertaken using NICE’s three Appraisal Committees. The experiment included five attributes: (1) Incremental cost-effectiveness (2) Degree of economic uncertainty (3) Age of the target population (4) Baseline health-related quality of life (5) Availability of other therapies A choice questionnaire detailing 18 scenarios was administered to NICE’s Appraisal Committees. For each scenario, respondents were asked to indicate whether they would recommend the intervention under consideration or not. The stated preference data obtained from respondents were analysed using a random effects logit regression model. Results A response rate of 46% was obtained from the Appraisal Committees. The regression model suggests that increases in cost-effectiveness, economic uncertainty, and the availability of other therapies are associated with statistically significant reductions in the odds of adoption (puncertainty; equity; cost-effectiveness; public health

Charge-odd and single-spin effects in two-pion production in ep collisions

We consider double-photon and bremsstrahlung mechanisms for the production of two charged pions in high-energy electron (or proton) scattering off a transversely polarised proton. Interference between the relevant amplitudes generates a charge-odd contribution to the cross-section for the process. In the kinematical configuration with a jet nearly collinear to the electron, the spin-independent part may be used to the determine phase differences for pion-pion scattering in states with orbital momentum 0 or 2 and 1, while for the configuration with a jet nearly collinear to the proton, the spin-dependent part may be used to explain the experimental data for single-spin correlations in the production of negatively charged pions. We also discuss the backgrounds and estimate the accuracy of the results to be better than 10 %. In addition, simplified formulae derived for specific kinematics, with small total transverse pion momenta, are given. The accuracy is estimated to remain at the same level despite the lower energy.Comment: 13 pp, LaTeX 2e, uses acromake packag

Theory Summary

A summary is presented of the more theoretical aspects of the presentations made at Hyperon~99. In addition, some material is covered which was not presented at the symposium but which I feel is pertinent to the main theme of hyperons and/or, more in particular, to discussions conducted during the symposium

Transversity K Factors for Drell-Yan

The question of the K factor in transversely polarised Drell-Yan (DY) processes is examined. The transverse-spin case is peculiar for the absence of a reference point in deeply inelastic scattering (DIS). Therefore, in order to study more fully the possible effects of higher-order corrections on DY asymmetries, a DIS definition for transversity is devised using a hypothetical scalar (Higgs-like) vertex. The results show that some care may be required in interpreting experimentally extracted partonic transversity, in particular when comparing with model calculations or predictions.Comment: 8 pages, 4 figures (eps and feynmp); uses standard LaTeX/MiKTeX packages [svjour.cls, amsmath, bbm, feynmp, graphicx, maybemath, natbib, psfrag, slashed] some homespun packages (included in the zip file); discussion augmented, 1 figure removed; resubmitted to Eur. Phys. J. section

Non-Universality and Evolution of the Sivers Function

We examine the large-x QCD evolution of the twist-three gluonic-pole strength defining an effective T-odd Sivers function, where evolution of the T-even transverse-spin DIS structure function g2 is multiplicative. The result corresponds to a colour-factor modified spin-averaged twist-two evolution.Comment: Presented at the ECT* Workshop on Recent Advances in Perturbative QCD and Hadronic Physics (20-25 July 2009} - final version (minor modifications

‘Ethnic group’, the state and the politics of representation

The assertion, even if only by implication, that ‘ethnic group’ categories represent ‘real’ tangible entities, indeed identities, is commonplace not only in the realms of political and policy discourse but also amongst contemporary social scientists. This paper, following Brubaker (2002), questions this position in a number of key respects: of these three issues will dominate the discussion that follows. First, there is an interrogation of the proposition that those to whom the categories/labels refer constitute sociologically meaningful ‘groups’ as distinct from (mere) human collectivities. Secondly, there is the question of how these categories emerge, i.e. exactly what series of events, negotiations and contestations lie behind their construction and social acceptance. Thirdly, and as a corollary to the latter point, we explore the process of reification that leads to these categories being seen to represent ‘real things in the world’ (ibid.)

Determination of the Kobayashi-Maskawa-Cabibbo matrix element V_{us} under various flavor-symmetry-breaking models in hyperon semileptonic decays

We study the success to describe hyperon semileptonic decays of four models that incorporate second-order SU(3) symmetry breaking corrections. The criteria to assess their success is by determining V_{us} in each of the three relevant hyperon semileptonic decays and comparing the values obtained with one another and also with the one that comes from K_{l3} decays. A strong dependence on the particular symmetry breaking model is observed. Values of V_{us} which do not agree with the one of K_{l3} are generally obtained. However, in the context of chiral perturbation theory, only the model whose corrections are O(m_s) and O(m_s^{3/2}) is successful. Using its predictions for the f_1 form factors one can quote a value of V_{us} from this model, namely, V_{us}=0.2176\pm 0.0026, which is in excellent agreement with the K_{l3} one.Comment: Final versio