13,256 research outputs found

    An Iterative Cyclic Algorithm for Designing Vaccine Distribution Networks in Low and Middle-Income Countries

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    The World Health Organization's Expanded Programme on Immunization (WHO-EPI) was developed to ensure that all children have access to common childhood vaccinations. Unfortunately, because of inefficient distribution networks and cost constraints, millions of children in many low and middle-income countries still go without being vaccinated. In this paper, we formulate a mathematical programming model for the design of a typical WHO-EPI network with the goal of minimizing costs while providing the opportunity for universal coverage. Since it is only possible to solve small versions of the model optimally, we describe an iterative heuristic that cycles between solving restrictions of the original problem and show that it can find very good solutions in reasonable time for larger problems that are not directly solvable.Comment: International Joint Conference on Industrial Engineering and Operations Management- ABEPRO-ADINGOR-IISE-AIM-ASEM (IJCIEOM 2019). Novi Sad, Serbia, July 15-17t

    Timelike and spacelike hadron form factors, Fock state components and light-front dynamics

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    A unified description of spacelike and timelike hadron form factors within a light-front model was successfully applied to the pion. The model is extended to the nucleon to study the role of qqňČq \bar q pair production and of nonvalence components in the nucleon form factors. Preliminary results in the spacelike range 0‚ȧQ2‚ȧ10¬†(GeV/c)20 \le Q^2 \le 10 ~ (GeV/c)^2 are presented.Comment: 4 pages, espcrc1.sty. proceedings of FB XVIII (August 2006, Brazil), to be published in Nucl. Phys.

    Electromagnetic Hadron Form Factors and Higher Fock Components

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    Investigation of the spacelike and timelike electromagnetic form factors of hadrons, within a relativistic microscopical model characterized by a small set of hypothesis, could shed light on the components of hadron states beyond the valence one. Our relativistic approach has been successfully applied first to the pion and then the extension to the nucleon has been undertaken. The pion case is shortly reviewed as an illustrative example for introducing the main ingredients of our approach, and preliminary results for the nucleon in the spacelike range ‚ąí10(GeV/c)2‚ȧq2‚ȧ0-10 (GeV/c)^2\le q^2 \le 0 are evaluated.Comment: 8 pages, 6 figs, espcrc1.sty included. Proceedings of Fifth International Conference on Perspectives In Hadronic Physics, ICTP, May 22-26, 200

    Electromagnetic form factors of the nucleon in spacelike and timelike regions

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    An approach for a unified description of the nucleon electromagnetic form factors in spacelike and timelike regions is presented. The main ingredients of our model are: i)i) a Mandelstam formula for the matrix elements of the nucleon electromagnetic current; ii)ii) a 3-dimensional reduction of the problem on the Light-Front performed within the so-called {\tt Propagator Pole Approximation} ({\bf PPA}), which consists in disregarding the analytical structure of the Bethe-Salpeter amplitudes and of the quark-photon vertex function in the integration over the minus components of the quark momenta; iii)iii) a dressed photon vertex in the qqňČq\bar{q} channel, where the photon is described by its spin-1, hadronic component.Comment: 8 pages, 9 figs., macro added. Proceedings of the XI Conf. on Problems in Theoretical Nuclear Physics, Cortona, Oct. 11-14, 200

    Bioprospecção de actinobactérias da rizosfera para produção de metabólitos bioativos.

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    Actinobact√©rias rizosf√©ricas, t√™m mostrado grande potencial na produ√ß√£o de metab√≥litos bioativos, sendo o g√™nero das Streptomyces o mais bem estudado e com melhor potencial para produ√ß√£o destes compostos. Assim, o presente trabalho visou realizar a bioprospec√ß√£o de actinobact√©rias rizosf√©ricas e avaliar o potencial de seus metab√≥litos bioativos no controle de bact√©rias patog√™nicas. Foram isoladas linhagens de actinobact√©rias de plantas sadias de milho, cultivado em diferentes regi√Ķes edafoclim√°ticas do Estado de S√£o Paulo. As linhagens foram avaliadas quanto ao potencial de controle de Bacillus megaterium, Escherichia coli, Klebsiella spp., Pseudomonnas aeruginosa e Sthaphylococcus aureus. Os isolados que se mostraram eficientes em testes de antagonismo foram utilizados em ensaios de antibiose para verifica√ß√£o do potencial do composto bioativo no controle destes pat√≥genos. Foram isolados 60 actinobact√©rias, identificadas morfologicamente como sendo do g√™nero Streptomyces. Dentre estas, 31 inibiram pelo menos 1 dos 5 pat√≥genos em testes de antagonismos. Nos ensaios de antibiose, foi verificada a efici√™ncia dos metab√≥litos de 25 actinobact√©rias no controle dos pat√≥genos testados

    Estimativas de par√Ęmetros gen√©ticos e fenot√≠picos em n√≠vel de indiv√≠duo em popula√ß√Ķes segregantes de feijoeiro-comum.

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    O objetivo desse trabalho foi estimar os par√Ęmetros gen√©ticos e fenot√≠picos, em n√≠vel de indiv√≠duo, de popula√ß√Ķes segregantes de feijoeiro-comum, grupo carioca, para caracteres de escurecimento e produ√ß√£o de gr√£os.CONAF

    Genetic gain in an improvement program of irrigated rice in Minas Gerais.

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    An evaluation of the genetic improvement programme of irrigated rice of Minas Gerais (Brazil) estimated the genetic gain obtained in the 90s. Grain yield data of the advanced comparative trials of cultivars and lines of continuously flooded rice, conducted from 1990-91 to 2000-01, were used. The estimate of the genetic gain was obtained by the methodology of the adjusted means proposed by Breseghello (1998). The mean annual genetic gain in the 90s was 42.45+or-17.89 kg ha-1 (0.7% per year). The improvement programme proved auspicious for the development of lines that outmatched the controls. The mean of the cultivars released in the 90s did however not outstrip the mean of the elite lines, which were the genotypes with the highest means in this study and will be further evaluated in the ongoing programme

    Induction of seed coat darkening in common beans (Phaseolus vulgaris L.) and the association with cooking time after storage.

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    Carioca is the most important edible dry bean (Phaseolus vulgaris L.) grown in Brazil. It represents the largest dry bean market class in the world. The seed coat of carioca beans will darken under adverse harvest conditions and with the increasing of storage time. In general, darkened seeds are associated with older seeds that suffer from prolonged cooking times. A relatively new 'slow darkening' trait is available in carioca that delays seed coat darkening under storage. However, its effect on cooking time is unknown. The objective of this work was to evaluate two induction methods of seed coat darkening and to examine the effect of slow darkening trait on cooking time after storage. Lines derived from four segregating populations resulting from crossings between cultivar BRSMG Madrepérola with slow seed coat darkening, and the parents BRS Estilo, BRS Cometa, BRS Notável and BRS Sublime with normal darkening were evaluated. An experiment inlcuding 220 lines, 55 per population and the five parents, in a 15x15 triple lattice was conducted in the winter growing season in Brasilia. Seed coat darkening and cooking time traits were evaluated. Two methods for inducing seed coat darkening were compared: an accelerated aging test using UV light for 72 hours, and an extended storage for 90 days under ambient conditions. The correlation between the induction methods ranged from 0.77 to 0.85 for the different populations indicating either method could be used to discriminate lines with normal versus slow darkening trait. The percentage of light-colored grain lines was identified by both induction methods of seed coat darkening ranged from 75 to 85.7% in the populations. The genetic correlation between seed coat darkening and cooking time varied from -0.06 to -0.48, indicating that in some populations there is no significant genetic correlation between seed coat darkening and cooking time. Thus, light colored grains are not indicative of low cooking time, when they are considered genotypes with genetic variation for the seed coat darkening
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