Universal Parametric correlations at the soft edge of the spectrum of random matrix ensembles

We extend a recent theory of parametric correlations in the spectrum of random matrices to study the response to an external perturbation of eigenvalues near the soft edge of the support. We demonstrate by explicit non-perturbative calculation that the two-point function for level density fluctuations becomes, after appropriate rescaling, a universal expression.Comment: 8 pages, written in TeX, Preprint OUTP-94-10S (University of Oxford

Fertilização de pupunheira para produção de palmito.

Efeito da interação Nitrogênio-Fósforo, Nitrogênio-Potássio e Fósforo-Potássio no crescimento (cm) de pupunheira, na ausência de esterco de galinha. Efeito da interação Nitrogênio-Fósforo, Nitrogênio-Potássio e Fósforo-Potássio no crescimento (cm) de pupunheira, na presença de esterco de galinha. Efeito da interação Nitrogênio-Fósforo, Nitrogênio-Potássio e Fósforo-Potássio na produção (g/parcela) de palmito de pupunha, na ausência de esterco de galinha. Efeito da interação Nitrogênio-Fósforo, Nitrogênio-Potássio e Fósforo-Potássio na produção (g/parcela) de palmito de pupunha, na presença de esterco de galinha.bitstream/item/89190/1/PA-22-Manoel-Cravo.pd

Turbulence Hierarchy in a Random Fibre Laser

Turbulence is a challenging feature common to a wide range of complex phenomena. Random fibre lasers are a special class of lasers in which the feedback arises from multiple scattering in a one-dimensional disordered cavity-less medium. Here, we report on statistical signatures of turbulence in the distribution of intensity fluctuations in a continuous-wave-pumped erbium-based random fibre laser, with random Bragg grating scatterers. The distribution of intensity fluctuations in an extensive data set exhibits three qualitatively distinct behaviours: a Gaussian regime below threshold, a mixture of two distributions with exponentially decaying tails near the threshold, and a mixture of distributions with stretched-exponential tails above threshold. All distributions are well described by a hierarchical stochastic model that incorporates Kolmogorov's theory of turbulence, which includes energy cascade and the intermittence phenomenon. Our findings have implications for explaining the remarkably challenging turbulent behaviour in photonics, using a random fibre laser as the experimental platform.Comment: 9 pages, 5 figure

Rendimento do maracujazeiro irrigado com água salina em função das distâncias de plantio e da cobertura do solo.

O maracujazeiro-amarelo (Passiflora edulis f. flavicarpa Deg.) pela sua rusticidade, preferência pelo consumidor rápido retorno do capital investido é uma frutífera cultivada com viabilidade econômica em quase todo o Brasil. Neste sentido, foi desenvolvido no Município de Coronel Ezequiel, área semi-árida do Rio Grande do Norte, um experimento em blocos casualizados para avaliar componentes da produtividade da cultura sob irrigação com água salina, de condutividade elétrica 3,4 dS m-1. O esquema experimental adotado foi fatorial 4 x 22 referente as distâncias de plantio nas linhas de 3; 6; 9 e 12 m, em solo sem e com cobertura morta, em plantas sem e com poda do ápice da haste principal ao atingirem o arame de sustentação. O aumento da distância entre plantas nas linhas promoveu maior número de frutos por planta, aumento da massa média dos frutos, porém, reduziu a rodutividade da cultura. Comparativamente com dados da literatura obtidos de plantas irrigadas com água não salina, contata-se que a alta salinidade da água não comprometeu a capacidade produtiva do maracujazeiro-amarelo

Balance of the solar radiation in agroforestry systems in Central Amazonia.

Micrometerological observations have been used to study the radiation balance over recultivation areas in SHIFT agroforestry systems in Manaus-AM (Brasil). The radiation balance was compared with measurements obtained in a adjacent forest (Ducke Reserve)

Germany's 'coronavirus anomaly': Statistical evidence that early mass testing leads to low mortality rates

In this note, we present a statistical analysis of the mortality rates of COVID-19 for several selected European countries. We compare the countries' mortality rates with their respective number of tests as a function of the time since the first death. Our analysis shows that countries that either delayed mass testing, such as Italy, or have not fully adopted it, such as France and the UK, have had much higher mortality rates than Germany, which has adopted a policy of wide and early testing. Conversely, countries that have followed Germany's example, such as Portugal, have so far had comparatively low mortality rates

Changes in osmoregulatory metabolism of cotton genotypes during water deficit and recovery period.

The aim of this study was to evaluate the changes in osmoregulatory metabolism of cotton genotypes subjected to water deficit and recovery period. In a greenhouse, six cotton genotypes and two water managements were combined in a 6 x 2 factorial scheme, in a completely randomized design, evaluated after 14 and 22 days under water stress and recovery conditions, respectively. The water status, growth indicators and compatible solutes in the leaves were evaluated. The genotypes BRS Seridó, BRS Aroeira and BRS 7MH withstand better the stress condition because they had lower variations in their water potentials due to the osmotic adjustment and maintained their growth under water deficit conditions. The BRS 286 is the most sensitive genotype to the water deficit condition, since it showed greater variations in its water potential, which ultimately stopped its growth. Water replacement during the recovery period allowed growth resumption in most of the genotypes, mainly CNPA 5M and BRS 286. After the recovery period, variations in the concentrations of osmoregulators indicate the plasticity of cotton in regulating the concentrations of osmoregulators under favorable and unfavorable water conditions.Título em português: Mudanças no metabolismo osmorregulador de genótipos de algodoeiro durante déficit hídrico e período de recuperação