1,744 research outputs found
Heavy Quark Fluorescence
Heavy hadrons containing heavy quarks (for example, Upsilon-mesons) feature a
scale separation between the heavy quark mass (about 4.5 GeV for the b-quark)
and the QCD scale (about 0.3 GeV}) that controls effective masses of lighter
constituents. Therefore, as in ordinary molecules, the de-excitation of the
lighter, faster degrees of freedom leaves the velocity distribution of the
heavy quarks unchanged, populating the available decay channels in
qualitatively predictable ways. Automatically an application of the
Franck-Condon principle of molecular physics explains several puzzling results
of Upsilon(5S) decays as measured by the Belle collaboration, such as the high
rate of Bs*-anti Bs* versus Bs*-anti Bs production, the strength of three-body
B-anti B + pion decays, or the dip in B momentum shown in these decays. We
argue that the data is showing the first Sturm-Liouville zero of the
Upsilon(5S) quantum mechanical squared wavefunction, and providing evidence for
a largely b-anti b composition of this meson.Comment: 4 pages, 4 figures, Figure 2 updated and some typos corrected. To be
published in Physical Review Letter
Minimum of and the phase transition of the Linear Sigma Model in the large-N limit
We reexamine the possibility of employing the viscosity over entropy density
ratio as a diagnostic tool to identify a phase transition in hadron physics to
the strongly coupled quark-gluon plasma and other circumstances where direct
measurement of the order parameter or the free energy may be difficult.
It has been conjectured that the minimum of eta/s does indeed occur at the
phase transition. We now make a careful assessment in a controled theoretical
framework, the Linear Sigma Model at large-N, and indeed find that the minimum
of eta/s occurs near the second order phase transition of the model due to the
rapid variation of the order parameter (here the sigma vacuum expectation
value) at a temperature slightly smaller than the critical one.Comment: 22 pages, 19 figures, v2, some references and several figures added,
typos corrected and certain arguments clarified, revised for PR
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UK Skills and Productivity in an International Context
A nation's prosperity depends largely on its ability to raise the level of its productivity. The education level of its workforce, and how effectively the skills are used in the production processes, are considered important factors in this process. In this report we investigate the extent to which skills have contributed to recent productivity performance in the UK. We do this within a cross-country framework, where we compare the UK's productivity trajectories with those of other close competitors. We quantify the role played by different types of certified skills, both academic and vocational, taking account of the influence of other factors, such as capital investment and technological change. Furthermore, we assess the influence of intangible investments, usually excluded from published data and traditional growth studies. We use a wide range of data sources, and employ growth accounting and panel data econometric techniques.
The study begins with a comprehensive review of the literature on the role of human capital in productivity and growth, from both a theoretical and empirical point of view (section 1). We then provide a description of aggregate productivity and employment trends in section 2. Section 3 contains detailed results of the growth accounting decomposition and Section 4 summarises the econometric analysis. Sections 5 and 6 outline the key findings and conclusions emerging from this analysis.
The main research questions addressed in this report are:
• What have been the main sources of growth in the UK and other major economies since the recession? How have these differed relative to the previous periods?
• What is the link between skills and productivity/growth? How have skills contributed to growth over recent years?
• What is the contribution of different types of skills to growth? Where does the UK fare better and worse compared to international competitors?
• What is the role of training and other intangible assets in explaining productivity and growth outcomes? Do they interact differently with different types of skilled workers
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Productivity in the UK’s low-wage industries: a comparative cross-country analysis
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A phase 1 trial dose-escalation study of tipifarnib on a week-on, week-off schedule in relapsed, refractory or high-risk myeloid leukemia.
Inhibition of farnesyltransferase (FT) activity has been associated with in vitro and in vivo anti-leukemia activity. We report the results of a phase 1 dose-escalation study of tipifarnib, an oral FT inhibitor, in patients with relapsed, refractory or newly diagnosed (if over age 70) acute myelogenous leukemia (AML), on a week-on, week-off schedule. Forty-four patients were enrolled, two patients were newly diagnosed, and the rest were relapsed or refractory to previous treatment, with a median age of 61 (range 33-79). The maximum tolerated dose was determined to be 1200 mg given orally twice daily (b.i.d.) on this schedule. Cycle 1 dose-limiting toxicities were hepatic and renal. There were three complete remissions seen, two at the 1200 mg b.i.d. dose and one at the 1000 mg b.i.d. dose, with minor responses seen at the 1400 mg b.i.d. dose level. Pharmacokinetic studies performed at doses of 1400 mg b.i.d. showed linear behavior with minimal accumulation between days 1-5. Tipifarnib administered on a week-on, week-off schedule shows activity at higher doses, and represents an option for future clinical trials in AML
A Nonlinear Heat Equation with Temperature-Dependent Parameters
Abstract A nonlinear partial differential equation of the following form is considered: which arises from the heat conduction problems with strong temperature-dependent material parameters, such as mass density, specific heat and heat conductivity. Existence, uniqueness and asymptotic behavior of initial boundary value problems under appropriate assumptions on the material parameters are established. Both one-dimensional and two-dimensional cases are considered
Predictors of unfavourable tuberculosis treatment outcome in Bilene District, Gaza Province, Mozambique: A retrospective analysis, 2016 - 2019
Background. Tuberculosis (TB) is a serious public health problem and remains one of the leading causes of death from an infectious agent globally. Mozambique is one of 30 countries considered to have a high TB burden.Objectives. To describe the clinical characteristics of TB in children and adults in Bilene District in Gaza Province, Mozambique, over 43 months and to assess determinants of unfavourable treatment outcomes.Methods. This retrospective cohort study took place from 1 January 2016 to 31 July 2019 in Bilene District, Gaza. We included patients in the TB register at the Centro de Saúde de Macia TB unit with available data on final treatment outcome. Predictors of unfavourable outcomes were determined using multivariable logistic regression models.Results. A total of 3 012 TB-infected patients were registered in the TB unit of the Macia health facility during the study period: 358 (11.9%) were children (<14 years), 1 522 (50.5%) were male, and 2 581 (85.7%) were new TB cases. No bacteriological test was performed at diagnosis in 1 250 patients (41.5%). Treatment was successful in 2 863 patients (95.1%), with better outcomes in children than in adults (98.0% v. 94.6%; p=0.005). Although mortality (n=97; 3.2%) was low in both groups, the proportion who died was lower in children compared with adults (1.4% v. 3.5%; p=0.035). Multivariable logistic regression analysis showed that unfavourable outcomes were more likely in men compared with women (adjusted odds ratio (aOR) 1.48; 95% confidence interval (CI) 1.04 - 2.12; p=0.029), in patients with recurrent TB infection compared with newly infected patients (aOR 1.63; 95% CI 1.05 - 2.50; p=0.027), and in patients co-infected with TB and HIV compared with HIV-negative TB-infected patients (aOR 2.17; 95% CI 1.43 - 3.29; p<0.001). The factor conferring the most risk for an unfavourable outcome was positive microbiological sputum results (aOR 5.27; 95% CI 3.25 - 8.54; p<0.001).Conclusions. Factors independently associated with an unfavourable TB treatment outcome were male sex, recurrent TB infection, having positive microbiology, and co-infection with HIV. It remains crucial to improve data quality and adherence to TB screening and diagnostic algorithms
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