The nucleon and the nuclear force in the context of effective theory and path-integral methods

The nucleon structure and the nuclear force are investigated in the context of the non-perturbative path-integral method of hadronization. Starting from a microscopic quark-diquark model, the nucleon is generated as a relativistic bound state and an effective chiral meson-nucleon Lagrangian is derived. Many of the nucleon physical properties are studied using a theory of at most two free parameters.Comment: 8 pages, 4 figures. To appear in the proceedings of Pan American Advanced Studies Institute on New States of Matter in Hadronic Interactions (PASI2002), Campos do Jordao, Brazil, 7-18 Jan 200

Quasifree processes from nuclei: Meson photoproduction and electron scattering

We have developed a relativistic formalism for studying quasi-free processes from nuclei. The formalism can be applied with ease to a variety of processes and renders transparent analytical expressions for all observables. We have applied it to kaon photoproduction and to electron scattering. For the case of the kaon, we compute the recoil polarization of the lambda-hyperon and the photon asymmetry. Our results indicate that polarization observables are insensitive to relativistic, nuclear target, and distortion effects. Yet, they are sensitive to the reactive content, making them ideal tools for the study of modifications to the elementary amplitude -- such as in the production, propagation, and decay of nucleon resonances -- in the nuclear medium. For the case of the electron, we have calculated the spectral function of He-4. An observable is identified for the clean and model-independent extraction of the spectral function. Our calculations provide baseline predictions for the recently measured, but not yet fully analyzed, momentum distribution of He-4 by the A1-collaboration from Mainz. Our approach predicts momentum distributions for He-4 that rival some of the best non-relativistic calculations to date.Comment: To appear in the proceedings of International Symposium on Electromagnetic Interactions in Nuclear and Hadron Physics (EMI 2001), Osaka, Ibaraki, Japan, 4-7 Dec 200

The mass of the nucleon in a chiral quark-diquark model

The mass of the nucleon is studied in a chiral quark-diquark model. Both scalar and axial-vector diquarks are taken into account for the construction of the nucleon state. After the hadronization procedure to obtain an effective meson-baryon Lagrangian, the quark-diquark self-energy is calculated in order to generate the baryon kinetic term as well as the mass of the nucleon. It turns out that both the scalar and axial-vector parts of the self-energy are attractive for the mass of the nucleon. We investigate the range of parameters that can reproduce the mass of the nucleon.Comment: 10 pages, 6 figures. Numerical errors are corrected. Accepted to Phys. Rev. C72 (2005) 03520

Epidemiological impact of targeted interventions for people with diabetes mellitus on tuberculosis transmission in India: Modelling based predictions.

INTRODUCTION: Diabetes mellitus (DM) is a leading driver of tuberculosis (TB) disease in TB-DM burdened countries. We aimed to assess the impact on TB disease of several intervention strategies targeting people with DM in India. METHODS: A previously validated TB-DM mathematical model was extended to include interventions targeting DM individuals. The model stratified the population by age, DM status, TB infection status and stage, TB disease form, treatment, recovery, and intervention status. RESULTS: By 2050, different TB vaccination strategies (coverage of 50 % and vaccine efficacies ranging between 50 %-60 %) reduced TB incidence and mortality rates by 4.5 %-20.8 % and 4.1 %-22.1 %, respectively, and averted 3.1 %-12.8 % of TB disease cases in the total population. Number of vaccinations needed to avert one TB case (effectiveness) was 14-105. Varying the coverage levels of latent TB treatment (coverage of 50 %-80 % and drug effectiveness of 90 %) reduced TB incidence and mortality rates by 7.1 %-11.3 % and 8.2 %-13.0 %, respectively, averting 4.2 %-6.7 % of TB cases, with effectiveness of 38-40. Different scenarios for dual and concurrent treatment of those with TB and DM, reduced TB incidence and mortality rates by 0.1 %-0.4 % and 1.3 %-4.8 %, respectively, averting 0.1 %-0.2 % of TB cases, with effectiveness of 28-107. Different scenarios for managing and controlling DM (regardless of TB status) reduced TB incidence and mortality rates by 4.5 %-16.5 % and 6.5 %-22.2 %, respectively, averting 2.9 %-10.8 % of TB cases, with effectiveness of 6-24. CONCLUSION: Gains can be attained by targeting DM individuals with interventions to reduce TB burden. Most strategies were effective with <50 intervention doses needed to avert one TB disease case, informing key updates of current treatment guidelines

О перспективах рынка станкостроения с позиций анализа мировых тенденций, концепции жизненного цикла оборудования и CALS-технологий

В статье рассматриваются существующие методики выбора и проектирования нового оборудования с позиций анализа наиболее эффективных видах обработки, проводится анализ недостатков "классического" подхода к выбору оборудования. На основании CALS-технологий, принципа агрегатирования и паспортизации оборудования предлагается новая модель проектирования оборудования, позволяющая продлить жизненный цикл станков, уменьшить стоимость и сроки проектирования и изготовления оборудования.This article reviews the existing methods of choice and design of new equipment from the standpoint of analyzing the most effective forms of treatment, an analysis of the shortcomings of "classical" approach to the choice of equipment. Based on CALS-technologies, the principle of aggregation and certification of equipment, a new model for the design of equipment are proposed. This model allows to extend the life cycle of machines, reduce the cost and terms of designing and manufacturing equipment

How Does Population Viral Load Vary with the Evolution of a Large HIV Epidemic in sub-Saharan Africa?

Using mathematical modelling, we described the temporal evolution of population HIV-1 viral load in Tanzania throughout the epidemic. Population log10 viral load was found to be stable and not sensitive to epidemic dynamics. However, even modest increases in antiretroviral therapy (ART) coverage were reflected as appreciable reductions in population log10 viral load. As ART coverage expands in sub-Saharan Africa, population log10 viral load will increasingly become a powerful proxy for monitoring ART implementation and HIV incidence trends. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivitives 3.0 License, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially. http://creativecommons.org/licenses/by-nc-nd/3.0

The emerging face of the HIV epidemic in the Middle East and North Africa.

PURPOSE OF REVIEW: A volume of quality HIV data has materialized recently in the Middle East and North Africa (MENA). This review provides a thematic narrative of the patterns of HIV infection transmission in this region in light of these data. RECENT FINDINGS: Tens of integrated bio-behavioral surveillance surveys among hard-to-reach key populations at higher risk have been conducted in MENA in the recent years. Many of the studies reported appreciable and growing HIV prevalence. A few studies found alarming prevalence of as much as 87.2% HIV prevalence among people who inject drugs in Tripoli, Libya. The discovery of these hitherto hidden epidemics was unsettling to some authorities after years in which the importance of a focus on HIV prevention among key populations was not recognized. SUMMARY: The new data from MENA indicate growing HIV epidemics among key populations across the region. There is heterogeneity, however, as to which key populations are affected and in what proportions in different countries. In a few countries, HIV appears to affect only one key population and often there is substantial geographical heterogeneity in HIV transmission. Data are indicative of a growing HIV disease burden in this part of the globe, in contrast with the declining epidemics in most other regions

Quasifree kaon-photoproduction from nuclei in a relativistic approach

We compute the recoil polarization of the lambda-hyperon and the photon asymmetry for the quasifree photoproduction of kaons in a relativistic impulse-approximation approach. Our motivation for studying polarization observables is threefold. First, polarization observables are more effective discriminators of subtle dynamics than the unpolarized cross section. Second, earlier nonrelativistic calculations suggest an almost complete insensitivity of polarization observables to distortions effects. Finally, this insensitivity entails an enormous simplification in the theoretical treatment. Indeed, by introducing the notion of a ``bound-nucleon propagator'' we exploit Feynman's trace techniques to develop closed-form, analytic expressions for all photoproduction observables. Moreover, our results indicate that polarization observables are also insensitive to relativistic effects and to the nuclear target. Yet, they are sensitive to the model parameters, making them ideal tools for the study of modifications to the elementary amplitude --- such as in the production, propagation, and decay of nucleon resonances --- in the nuclear medium.Comment: 15 pages and 6 figures - submitted to PR