Bad semidefinite programs: they all look the same

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 $Ax <= b$ {\em badly behaved} if the value of $\sup { | A x <= b }$ is finite but the dual program has no solution with the same value for {\em some} $c.$ 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 $NP \cap co-NP$ 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

Key considerations in reimbursement decision-making for multiple sclerosis drugs in Australia

© 2018 Elsevier B.V. Background: : In Australia, the Pharmaceutical Benefits Advisory Committee (PBAC) advises on the reimbursement of drugs to be subsidised through the Pharmaceutical Benefits Scheme (PBS). This study aims to provide insights into the PBAC process and key considerations regarding the reimbursement of MS drugs in Australia. Methods: : The factors considered by the PBAC and its advice on whether to reimburse a drug are documented in public summary documents (PSDs). Qualitative content analysis of PSDs was conducted for all MS drugs considered by the PBAC between January 2006 and January 2018. Key issues identified by the PBAC were extracted and categorised. Common issues were identified and compared between drugs indicated for MS. Results: : A total of 23 submissions were evaluated relating to 13 MS drugs. Eight were recommended for reimbursement; an approval rate of 35% per submission and 62% per drug. Approval rates were higher for disease modifying treatments (73% per drug) than for symptomatic drugs (0% for nabiximols and fampridine submissions). The most frequently discussed issues in PSDs, irrespective of PBAC decision, were: (1) the validity of the indirect comparisons formed (n = 11); (2) the validity of the approach to obtain utilities (n = 6); (3) the lack of appropriate/long-term safety data (n = 8); and (4) the time horizon used in the economic models (n = 3). Conclusion: : A small but important number of issues have been consistently identified by the PBAC in relation to submissions for reimbursement of MS drugs. Drug developers and clinical trial investigators who are aware of these issues will be able to anticipate data requirements for reimbursement decision-making and thus potentially improve the evidence submitted for listing of MS drugs in Australia

Utilização da mandioca na alimentação de ruminantes na Amazônia.

bitstream/item/60457/1/CPATU-Doc73.pd

Implantação de ervais.

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