Procedimentos básicos do Laboratório de Fitopatologia da Embrapa Mandioca e Fruticultura.

O laboratório de fitopatologia da Embrapa Mandioca e Fruticultura dispõe de uma infraestrutura que possibilita execução e desenvolvimento de pesquisas e prestação de serviços aos produtores rurais. Apresenta grande potencial para realizar atividades rotineiras de diagnose direta de doenças, isolamento e identificação de microrganismos fitopatogênicos, preservação e manutenção de coleções de culturas de fungos

Fertilização nitrogenada do algodoeiro herbáceo irrigado. 1. Qualidade da fibra.

Com o objetivo de avaliar a qualidade da fibra do algodoeiro, cv. BRS 201, fertilizado com diferentes doses de uréia, um experimento de campo foi conduzido no município de Barbalha, CE, no ano de 2005. Utilizou-se o delineamento experimental em blocos ao acaso com quatro repetições e seis tratamentos, constituídos por seis doses de uréia (0, 60, 120, 180, 240, -1 300 kg.ha ), aplicadas em datas previamente estabelecidas, via água de irrigação. Utilizou-se para a aplicação da quantidade de água em cada evento de irrigação um sistema de aspersão em linha. Pela análise dos resultados, não se detectou diferença significativa entre as doses de uréia, sobre a qualidade da fibra, a qual atende ás exigências da indústria têxtil nacional para fibra média (30/32 mm) ou longa (32/34 mm), exceto com relação á finura, que apresentou valor médio de 5,1 micronaire.bitstream/CNPA/19898/1/BOLETIM82.pd

First report of Phytophthora boehmeriae on black wattle in Brazil.

Nota Técnica

First in-beam studies of a Resistive-Plate WELL gaseous multiplier

We present the results of the first in-beam studies of a medium size (10$\times$10 cm$^2$) Resistive-Plate WELL (RPWELL): a single-sided THGEM coupled to a pad anode through a resistive layer of high bulk resistivity ($\sim$10$^9 \Omega$cm). The 6.2~mm thick (excluding readout electronics) single-stage detector was studied with 150~GeV muons and pions. Signals were recorded from 1$\times$1 cm$^2$ square copper pads with APV25-SRS readout electronics. The single-element detector was operated in Ne\(5% $\mathrm{CH_{4}}$) at a gas gain of a few times 10$^4$, reaching 99$\%$ detection efficiency at average pad multiplicity of $\sim$1.2. Operation at particle fluxes up to $\sim$10$^4$ Hz/cm$^2$ resulted in $\sim$23$\%$ gain drop leading to $\sim$5$\%$ efficiency loss. The striking feature was the discharge-free operation, also in intense pion beams. These results pave the way towards robust, efficient large-scale detectors for applications requiring economic solutions at moderate spatial and energy resolutions.Comment: Accepted by JINS

Micro-Hole and Strip Plate (MHSP) operation in CF4

The Micro-Hole and Strip Plate (MHSP) is a hybrid electron multiplier which combines the working principles of a Gas Electron Multiplier (GEM) and a Micro-Strip Gas Counter (MSGC). The compact double stage electron multiplication processes found in the MHSP enables the realisation of higher gas gain than the lone GEM operation. Thermal neutron detection using gas detectors involves the use of gas with another suitable stopping gas, operated at elevated pressure to confine the products of the neutron- reaction. It is, however, well known that the gain of GEMs drops too sharply with increasing chamber pressure.http://www.sciencedirect.com/science/article/B6TJM-4NS2G9V-D/1/497af6476b376b1c2f407a3fa7ff735

The origin of power-law distributions in deterministic walks: the influence of landscape geometry

We investigate the properties of a deterministic walk, whose locomotion rule is always to travel to the nearest site. Initially the sites are randomly distributed in a closed rectangular ($A/L \times L)$ landscape and, once reached, they become unavailable for future visits. As expected, the walker step lengths present characteristic scales in one ($L \to 0$) and two ($A/L \sim L$) dimensions. However, we find scale invariance for an intermediate geometry, when the landscape is a thin strip-like region. This result is induced geometrically by a dynamical trapping mechanism, leading to a power law distribution for the step lengths. The relevance of our findings in broader contexts -- of both deterministic and random walks -- is also briefly discussed.Comment: 7 pages, 11 figures. To appear in Phys. Rev.