119 research outputs found

    A Generalized Fluctuation-Dissipation Theorem for Nonlinear Response Functions

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    A nonlinear generalization of the Fluctuation-Dissipation Theorem (FDT) for the n-point Green functions and the amputated 1PI vertex functions at finite temperature is derived in the framework of the Closed Time Path formalism. We verify that this generalized FDT coincides with known results for n=2 and 3. New explicit relations among the 4-point nonlinear response and correlation (fluctuation) functions are presented.Comment: 34 pages, Revte

    Measurement of the B0 Lifetime and Oscillation Frequency using B0->D*+l-v decays

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    The lifetime and oscillation frequency of the B0 meson has been measured using B0->D*+l-v decays recorded on the Z0 peak with the OPAL detector at LEP. The D*+ -> D0pi+ decays were reconstructed using an inclusive technique and the production flavour of the B0 mesons was determined using a combination of tags from the rest of the event. The results t_B0 = 1.541 +- 0.028 +- 0.023 ps, Dm_d = 0.497 +- 0.024 +- 0.025 ps-1 were obtained, where in each case the first error is statistical and the second systematic.Comment: 17 pages, 4 figures, submitted to Phys. Lett.

    Seletividade, eficiência de controle de plantas daninhas e persistência no solo de imazamox aplicado na cultura do feijoeiro.

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    O presente trabalho teve como objetivo avaliar a seletividade, o controle de plantas daninhas e a persistência no solo de imazamox aplicado na cultura do feijoeiro, durante os anos de 1995 a 1997. Nos experimentos de seletividade foram testados: imazamox (20, 30 e 40 g i.a./ha), imazamox + bentazon (30+480 g i.a./ha), imazamox + fomesafen (30+125 g i.a./ha) e testemunha nas cultivares Pérola, Jalo Precoce, Novo Jalo e Xamego. Os experimentos foram mantidos livres de plantas daninhas e foram avaliadas a fitotoxicidade visual e a produção de grãos. Nos experimentos de eficiência de controle de plantas daninhas foram testados: imazamox (20, 30 e 40 g i.a./ha), bentazon (480 g i.a./ha), fomesafen (125 e 250 g i.a./ha), imazamox + bentazon (30+480 g i.a./ha), imazamox + fomesafen (30 + 125 g i.a./ha), bentazon / imazamox (480/30 g i.a/ha, aplicação seqüencial), fomesafen/imazmox (125/30 g i.a./ha, aplicação seqüencial), fomesafen/fomesafen (100/100 g i.a./ha, aplicação seqüencial) e testemunha. Foram avaliadas as porcentagens de controle de Euphorbia heterophylla e Bidens pilosa. Para o estudo da persistência de imazamox no solo, foram conduzidos experimentos em dois locais: Goiânia, GO (argiloso) e Jussara, GO (arenoso). Imazamox (40 g i.a./ha) causou injúrias à cultura do feijoeiro que acarretaram redução de 15% na produtividade (média dos experimentos). A mistura de imazamox e bentazon causou menor grau de injúrias no feijoeiro, obtendo-se ganhos de produtividade de 8% (médias dos experimentos). Imazamox mostrou-se ineficiente para o controle de Bidens pilosa, enquanto para Euphorbia heterophylla observou-se controle eficiente a partir da dose de 40 g i.a./ha. Aplicações seqüenciais de fomesafen/imazamox (125/30 g i.a/ha) apresentaram controle eficiente de Euphorbia heterophylla e Bidens pilosa. A persistência de imazamox no solo, para ambos os locais, foi maior em 1995 que 1996. Isto foi devido à maior umidade do solo em 1996. A sensibilidade das culturas sucedâneas aos resíduos de imazamox no solo foi, em ordem decrescente: sorgo, milho e arroz. O período entre a aplicação do herbicida e o plantio da cultura sucedânea (INP) variou de acordo com a sensibilidade das culturas aos resíduos de imazamox no solo e à sua persistência. Considerando ambos os locais e anos, o INP variou de 68 a 111 dias para milho, 78 a 139 dias para sorgo e 25 a 75 dias para o arroz

    Whole-genome sequencing reveals host factors underlying critical COVID-19

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    Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

    High-speed aerodynamics of several blunt-cone configurations

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    Cross-continental differences in patterns of predation: will naive moose in Scandinavia ever learn?

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    Predation has been recognized as a major selective force in the evolution of behavioural characteristics of mammals. As a consequence of local predator extinction, prey may lose knowledge about natural predators but usually express behavioural adjustments after return of predators. Human harvest may replace natural predation but prey selection may differ from that of natural predators leading to a change in the behavioural response of prey. We show that hunting success (HS) of re-colonizing wolves (Canis lupus) on moose (Alces alces) in Scandinavia was higher than reported in North America, where moose have been continuously exposed to wolves and grizzly bears. We found no evidence that moose expressed behavioural adjustments that lowered the HS of wolves in territories that had been occupied by wolves for up to 21 years. Moose behaviour towards wolves and humans typically differs in Scandinavia compared to North America. We explain the differences found to be caused by variation in predation pressure by large carnivores and the rate, and mode, of human harvest during the twentieth century
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