5,122 research outputs found

    Bad semidefinite programs: they all look the same

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    Conic linear programs, among them semidefinite programs, often behave pathologically: the optimal values of the primal and dual programs may differ, and may not be attained. We present a novel analysis of these pathological behaviors. We call a conic linear system Ax<=bAx <= b {\em badly behaved} if the value of supAx<=b\sup { | A x <= b } is finite but the dual program has no solution with the same value for {\em some} c.c. We describe simple and intuitive geometric characterizations of badly behaved conic linear systems. Our main motivation is the striking similarity of badly behaved semidefinite systems in the literature; we characterize such systems by certain {\em excluded matrices}, which are easy to spot in all published examples. We show how to transform semidefinite systems into a canonical form, which allows us to easily verify whether they are badly behaved. We prove several other structural results about badly behaved semidefinite systems; for example, we show that they are in NPcoNPNP \cap co-NP in the real number model of computing. As a byproduct, we prove that all linear maps that act on symmetric matrices can be brought into a canonical form; this canonical form allows us to easily check whether the image of the semidefinite cone under the given linear map is closed.Comment: For some reason, the intended changes between versions 4 and 5 did not take effect, so versions 4 and 5 are the same. So version 6 is the final version. The only difference between version 4 and version 6 is that 2 typos were fixed: in the last displayed formula on page 6, "7" was replaced by "1"; and in the 4th displayed formula on page 12 "A_1 - A_2 - A_3" was replaced by "A_3 - A_2 - A_1

    Diversidade florística em quintais agroflorestais de agroecossistemas familiares da comunidade Nova Canaã, Rio Preto da Eva-AM.

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    Este trabalho teve por objetivo verificar a diversidade de espécies cultivadas em pomares caseiros de agroecossistemas, onde trabalhavam agricultores familiares da comunidade Vila Canaã

    Association between genetic polymorphisms in apoptosis-related genes and risk of cutaneous melanoma in women and men

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    The P53 Arg72Pro, MDM2 c.+309T > G, BAX c.-248G > A, and BCL2 c.-717C > A polymorphisms have variable roles in the apoptosis pathways. The P53 Arg72Pro, MDM2 c.+309T > G, BAX c.-248G > A, and BCL2 c.-717C > A polymorphisms have variable roles in the apoptosis pathways. Genomic DNA of 200 CM patients and 215 controls was analyzed by PCR-RFLP. In women, the frequencies of BAX GG (83.0% vs. 71.0%, P = 0.04), BM AA (32.0% vs. 15.0%, P = 0.003), P53 ArgArg plus BAX GG (84.9% vs. 63.2%, P = 0.01), P53 ArgArg plus BCL2 AA (37.0% vs. 13.1%, P = 0.003), BAX GG plus BCL2 AA (70.3% vs. 33.3%, P = 0.001), MDM2 GG plus BAX GG plus BCL2 AA (27.3% vs. 3.7%, P = 0.03), and P53 ArgArg plus MDM2 GG plus BAX GG plus BCL2 AA (33.3% vs. 5.6%, P = 0.04) genotypes were higher in patients than in controls. Female carriers of the respective genotypes were under 1.98 (95% CI: 1.01-3.91), 2.87 (95% CI: 1.43-5.77), 3.48 (95% CI: 1.34-9.04), 4.23 (95% CI: 1.63-10.96), 6.04 (95% CI: 2.10-17.37), 25.61 (95% CI: 1.29-507.24), and 25.69 (95% CI: 1.11-593.59)-fold increased risks for CM than others, respectively. In men, the frequencies of BCL2 CA + AA (83.0% vs. 67.6%, P = 0.01) and MDM2 TG + GG plus BCL2 CA + AA (94.2% vs. 68.3%, P = 0.003) genotypes were higher in patients than in controls. Male carriers of the respective genotypes were under 2.43 (95% CI: 1.23-4.82) and 9.22 (95% CI: 2.16-39.31)-fold increased CM risks than others, respectively. The data suggest for the first time that P53 Arg72Pro, MDM2 c.+309T > G, BAX c.-248G > A, and BCL2 c.-717C > A polymorphisms, enrolled in apoptosis pathways, constitute distinct determinants of CM in women and men742135141FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2009/12602-0; 2010/18904-

    Implantação de ervais.

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    Distribuição e propagacao da erva-mate, area de distribuicao natural, clima, solos; Propagacao da erva-mate: selecao de arvores matrizes, colheita de sementes, separacao de sementes, estratificacao de sementes, conservacao de sementes, construcao do viveiro, construcao das sementeiras, semeadura, germinacao, cuidados com as plântulas e repicagem, recipientes, propagacao vegetativa, doenças de sementeira e viveiro, adubarão de mudas em viveiro, justificação das mudas para o plantio; Preparo e conservacao do solo; Espaçamentos: pequenos produtores, médios e grandes produtores; Plantio: época de plantio e proteção das mudas, adubação de plantio; Replantio; Associação com outras culturas no ano do plantio; Poda de formação.bitstream/CNPF-2009-09/15737/1/circ-tec41.pd

    Diversidade florística em quintais agroflorestais de quatro localidades, Parintins - Amazonas.

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    O objetivo deste trabalho foi verificar a diversidade das espécies em pomares caseiros no assentamento de Vila Amazônia

    Reflexões sobre agricultura familiar, inovação e desenvolvimento na Amazônia.

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    O texto apresenta algumas reflexões sobre o ecossistema amazônico no seu aspecto físico, de exploração e da fragilidade desse ambiente quando se trata de uso dos recursos naturais. Traz para a discussão aspectos da diversidade biológica e sociocultural, bem como os efeitos das políticas governamentais sobre esse ambiente. Enfatiza e caracteriza a agricultura familiar amazônica e suas relações com o ambiente. Analisa a importância dos saberes locais no processo de geração e transferência de tecnologias e a importância de se juntar esses saberes com os conhecimentos científicos. A conjunção dos conhecimentos gera tecnologias adequadas ao ambiente, as quais, por sua vez, geram inovação e desenvolvimento. A participação das pessoas é importante para que ocorra a inovação. Neste aspecto, buscam-se, cada vez mais, metodologias que permitam analisar e inserir as pessoas nos processos de desenvolvimento

    Deep electronic states in ion-implanted Si

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    In this paper we present an overview of the deep states present after ion-implantation by various species into n-type silicon, measured by Deep Level Transient Spectroscopy (DLTS) and high resolution Laplace DLTS (LDLTS). Both point and small extended defects are found, prior to any anneal, which can therefore be the precursors to more detrimental defects such as end of range loops. We show that the ion mass is linked to the concentrations of defects that are observed, and the presence of small interstitial clusters directly after ion implantation is established by comparing their behaviour with that of electrically active stacking faults. Finally, future applications of the LDLTS technique to ion-implanted regions in Si-based devices are outlined.</p

    Estabelecimento de andiroba (Carapa guianensis Aubl e Carapa procera Condolle) em sistemas agroflorestais em estágio avançado de desenvolvimento.

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    A andiroba (Carapa guianensis e Carapa procera) é uma espécie de uso múltiplo, de grande importância econômica, ecológica e social. O presente trabalho objetivou avaliar o crescimento em altura e DAP da andirobeira implantada em sistemas agroflorestais em estágio avançado de desenvolvimento
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