Linear Theory of Electron-Plasma Waves at Arbitrary Collisionality

The dynamics of electron-plasma waves are described at arbitrary collisionality by considering the full Coulomb collision operator. The description is based on a Hermite-Laguerre decomposition of the velocity dependence of the electron distribution function. The damping rate, frequency, and eigenmode spectrum of electron-plasma waves are found as functions of the collision frequency and wavelength. A comparison is made between the collisionless Landau damping limit, the Lenard-Bernstein and Dougherty collision operators, and the electron-ion collision operator, finding large deviations in the damping rates and eigenmode spectra. A purely damped entropy mode, characteristic of a plasma where pitch-angle scattering effects are dominant with respect to collisionless effects, is shown to emerge numerically, and its dispersion relation is analytically derived. It is shown that such a mode is absent when simplified collision operators are used, and that like-particle collisions strongly influence the damping rate of the entropy mode.Comment: 23 pages, 10 figures, accepted for publication on Journal of Plasma Physic

Prevalence of Campylobacterin chickens from different production systems

info:eu-repo/semantics/draf

Adubação com N, P e K na cultura do arroz, em agricultura familiar, no Município de São Sebastião da Boa Vista, Marajó, PA.

bitstream/item/27535/1/Com.tec.172.pd

Doses de N, P e K na cultura do arroz, para agricultura familiar, no Município de Salvaterra, Marajó, PA.

bitstream/item/27926/1/Com.tec.208.pdfDisponível também on-line

Polyphenols and sugars recovery from autohydrolysis of pineapple waste

[Excerpt] The aim of this research was to evaluate the influence of temperature, time and mass/ volume ratio on the release of sugars and polyphenols using an autohydrolysis procedure from pineapple waste. A Box-Bhenken design was used with three factors (time, temperature and mass/volume ratio) and three levels was used. All treatments were performed in triplicate. Nine central points were used. For autohydrlosysis treatments, an oil bath was used [1]. After autohydrolysis, liquid phases or hydrolysates were analyzed for glucose and fructose concentration by high performance liquid chromatography (HPLC) [2]. The FolinCiocalteu assay was used to measure total polyphenols of hydrolysates [3] and HPLC to identify these molecules [4]. (...

Biodiversidade de actinobactérias do solo da caatinga para controle biológico de pragas.

Resumo: Actinobactérias são bactérias gram-positivas e constituem boa parte da população microbiana do solo. Este trabalho teve como objetivo estudar as actinobactérias do solo do Bioma Caatinga, a fim de descobrir espécies que forneçam controle biológico dos fungos Pyricularia grisea e Pythium aphanidermatum, responsáveis por causar doenças em plantas. Do total de isolados obtidos, 14 obtiveram resultado no controle destes fungos, e 2 já foram identificados. Destes 2, um apresenta-se como provável espécie nova, e está sendo objeto de estudo aprofundado. Este trabalho mostra como é importante preservar a Caatinga, pois no seu solo vivem microrganismos que podem ser capazes de desempenhar resultados positivos tanto na agricultura quanto na indústria. Abstract: Actinomycetes are gram-positive bacteria and constitute a large part of the soil microbial population. This work aims to study the soil actinomycetes from the Caatinga, in order to discover species that provide biological control of Pyricularia grisea and Pythium aphanidermatum, fungi responsible for causing diseases in plants. Of the total isolates, 14 obtained result in control of these fungi, and 2 have been identified. Of these two, one is presented as probable new species, and is being studied depth. This work shows how important it is to preserve the Caatinga, as in its soil lives microorganisms that might be able to perform positive results in both agriculture and industry

Adubação NPK na cultura do amendoim (Arachis hypogaea L.) cultivada em sistema de pesquisa participativa em agricultura familiar, no Município de Ponta de Pedras, PA.

bitstream/item/27538/1/com.tec.88.pd

Autohydrolysis extraction of bioactive compounds from pineapple waste

The aim of this research was to evaluate the influence of temperature, time and mass/volume ratio on the release of sugars and polyphenols using an autohydrolysis procedure from pineapple waste and determine its antioxidant activity. A Box-Bhenken design was used with three factors (time, temperature and mass/volume ratio) at three levels. All treatments were performed in triplicate. For autohydrolysis treatments, an oil bath was used [1]. After extraction process, liquid phases or hydrolysates were analyzed for glucose and fructose concentration by high performance liquid chromatography (HPLC) [2]. The Folin-Ciocalteu assay was used to measure total polyphenols of hydrolysates [3] and HPLC to identify these molecules [4]. Free radical scavenging activity (DPPH assay) and radical cation decolorization assay (ABTS) were assayed [5]. Figure 1, shows the antioxidant activity obtained from experimental matrix Box-Bhenken design from autohydrolysis treatments of pineapple waste. It was observed most treatments have higher activity than control, this is due to the abundance of bioactive compounds present in the hydrolysates. Conclusion: Autohydrolysis process is a good alternative for an effective extraction (using water as only reaction medium) of value-added compounds that can be used for alcoholic drinks enriched with natural antioxidants. In addition, this technology is an environmentally friendly extraction alternative in compared with traditional chemical process