1,576 research outputs found
The hydrostatic equilibrium and Tsallis equilibrium for self-gravitating systems
Self-gravitating systems are generally thought to behavior non-extensively
due to the long-range nature of gravitational forces. We obtain a relation
between the nonextensive parameter q of Tsallis statistics, the temperature
gradient and the gravitational potential based on the equation of hydrostatic
equilibrium of self-gravitating systems. It is suggested that the nonextensive
parameter in Tsallis statistics has a clear physical meaning with regard to the
non-isothermal nature of the systems with long-range interactions and Tsallis
equilibrium distribution for the self-gravitating systems describes the
property of hydrostatic equilibrium of the systems.Comment: 7 pages, 9 Reference
Sobrevivência e obtenção de mutantes induzidos por agentes mutagênicos em Metarhizium anisopliae
Uma linhagem selvagem do fungo entomopatogênico Metarhizium anisopliae foi submetida à ação de três agentes mutagênicos: radiação gama, luz ultravioleta e ácido nitroso. Curvas de sobrevivência foram obtidas para cada mutagênicos utilizado e mutantes foram selecionados a partir de doses dos mutagênicos que proporcionassem de 1 a 5% de sobrevivência. Mutantes morfológicos para a coloração de conídios e mutantes auxotróficos foram isolados. Mutantes para coloração de conidios foram agrupados em duas classes, uma com conídios amarelos e outra com conídios vinho pálido. Os mutantes auxotróficos obtidos foram deficientes para aminoácidos e vitaminas e mais de 58% deles eram auxotróficos para prolina/argmina. Radiação gama foi o mutagênico mais eficiente com uma porcentagem de obtenção de mulantes auxotróficos de aproximadamente 0,2%, seguido pela luz ultravioleta (0.12%) e pelo ácido nitroso (0.06%).Os mulantes morfológicos e auxotróficos obtidos até o momento em Metarhizium anisopliae foram revistos.A wild strain of Metarhizium anisopliae, an entomopathogenic fungus, was submitted to three mutagenic agents: gamma radiation, ultraviolet light and nitrous acid. Survival curves were obtained and mutants were selected using different mutagenic doses which gave 1 to 5% survival. Morphological and auxotrophic mutants were isolated. Morphological mutants were grouped in a class with yellow conidia and other with pale vinaceous conidia as opposed to the green wild type conidia. Auxotrophic mutants had requirements for vitamin and aminoacid biosynthesis. More than 58% of the total auxotrophk mutants required proline/aipnine. Gamma radiation showed to be the most efficient mutagenic agent giving 0.2% of auxotrophk mutants followed by ultraviolet light (0.12%) and nitrous acid (0.06%).The conidial colour and auxotrophk mutants isolated until now from M. anisopliae were reviewed
Growth, Yield, And Postharvest Quality In Eggplant Produced Under Different Foliar Fertilizer (spirulina Platensis) Treatments
This study evaluated the growth, yield, and postharvest quality of eggplant grown under different foliar fertilizer treatments with Spirufert® (Spirulina platensis). The treatments consisted of four fertilizer concentrations applied at four phenological stages: M1 (10, 15, 25, and 35 g L-1), M2 (15, 20, 30, and 40 g L-1), M3 (20, 25, 35, and 45 g L-1), and M4 (control plants, water spraying only). For Postharvest experiments were conducted in a 4 x 5 factorial design corresponding to the four treatments in the field experiment and five storage times. Spirufert® applied at lower concentrations (M1) resulted in greater fruit yield without affecting the foliar concentrations of N, P, K, and Na. Higher fertilizer concentrations (M3) increased vegetative growth but reduced eggplant yield. Fruit color parameters and soluble solids contents were not affected by fertilizer application, but pulp firmness was more stable in M1 fruits stored for up to six days.3763893390
Selection of resistant upland cotton genotypes challenged with aggressive isolates of Meloidogyne incognita race 3
Received: July 11th, 2022 ; Accepted: August 19th, 2022 ; Published: August 25th, 2022 ; Correspondence: [email protected] study aimed to select populations of M. incognita race 3 for screening cotton
genotypes as part of a breeding program for the development of resistant cotton cultivars. Five
isolates of M. incognita race 3, collected in Western Paraná, Brazil, were tested for virulence and
aggressiveness against the cotton cultivars FM966 (susceptible), IAC 24 (resistant), CD 409, and
FMT 701 (moderately resistants) under greenhouse conditions, and following a factorial design
with five replicates. Thirty-one cotton genotypes were screened against the three most aggressive
isolates of M. incognita race 3 tested before and kept under greenhouse conditions following a
factorial design with five replicates. Experiments run under greenhouse conditions had single
cotton plants inoculated with 5,000 eggs/J2 of M. incognita and were assessed at 120 days after
inoculation considering the variables gall index, egg mass index, total eggs, and reproduction
factor. The same genotypes tested under greenhouse conditions were also grown in a field infested
with M. incognita race 3 in a randomized block design with 10 replicates. In the field, the
M. incognita population was monitored by the quantification of J2 forms in soil samples collected
before sowing, 60 days after sowing (DAS), and 120 DAS. A gall index score was used to
evaluate the roots of cotton genotypes at 120 DAS. The isolate from Umuarama was the most
aggressive, followed by Moreira Sales and Iporã. The genotypes CD 05-419, CD 05-945,
CD 05-1087, and CD 05-1170 showed resistance against M. incognita race 3 under greenhouse
and field conditions
Higher spin fields and the problem of cosmological constant
The cosmological evolution of free massless vector or tensor (but not gauge)
fields minimally coupled to gravity is analyzed. It is shown that there are
some unstable solutions for these fields in De Sitter background. The back
reaction of the energy-momentum tensor of such solutions to the original
cosmological constant exactly cancels the latter and the expansion regime
changes from the exponential to the power law one. In contrast to the
adjustment mechanism realized by a scalar field the gravitational coupling
constant in this model is time-independent and the resulting cosmology may
resemble the realistic one.Comment: 15 pages, Latex twic
What does the nonextensive parameter q stand for in self-gravitating systems ?
It is natural important question for us to ask what the nonextensive
parameter stands for when Tsallis statistics is applied to the self-gravitating
systems. In this paper, some properties of the nonextensive parameter and
Tsallis equilibrium distribution for the self-gravitating system are discussed
in the framework of nonextensive kinetic theory. On the basis of the solid
mathematical foundation, the nonextensive parameter can be expressed by a
formula with temperature gradient and the gravitational potential and can be
presented the physical meaning with regard to the non-isothermal
(nonequilibrium stationary state) nature of the systems with long-range
interactions. We come to the conclusion that Tsallis equilibrium distribution
is corresponding to the physical state of self-gravitating system at the
hydrostatic equilibrium.Comment: 11 pages, 25 references. The Twelfth United Nations/European Space
Agency workshop on basic space science. May 24-28 2004, Beijing, Chin
Modeling the Searching Behavior of Social Monkeys
We discuss various features of the trajectories of spider monkeys looking for
food in a tropical forest, as observed recently in an extensive {\it in situ}
study. Some of the features observed can be interpreted as the result of social
interactions. In addition, a simple model of deterministic walk in a random
environment reproduces the observed angular correlations between successive
steps, and in some cases, the emergence of L\'evy distributions for the length
of the steps.Comment: 7 pages, 3 figure
Are biological species and higher-ranking categories real? Fish folk taxonomy on Brazil’s Atlantic Forest coast and in the Amazon
Analysis of Brazilian fishers' classifications of 24 marine (Atlantic coast) and 24 freshwater (Amazon) fish species reveals that fishers from the Atlantic coast identify fish mainly through generic names (primary lexemes), while riverine Amazonian fishers typically identify them through binomials. The similarity of Amazonian fish species seems to contribute to the detailed folk taxonomy used by riverine fishers. High-ranking groups called "relatives" or "cousins" are sorted by fishers in terms of similarities of habitat, diet, and morphology and, secondarily, behavior. The general correspondence between the folk and scientific taxonomies reinforces the reality of both the supracategories used by these fishers and the biological groups as discontinuities in nature. Given the urgency of biological inventories and the lack of knowledge of high-biodiversity environments such as the Atlantic Forest and the Amazon, these results suggest that fisher knowledge and experience could contribute to scientific research.49229130
Spin relaxation time, spin dephasing time and ensemble spin dephasing time in -type GaAs quantum wells
We investigate the spin relaxation and spin dephasing of -type GaAs
quantum wells. We obtain the spin relaxation time , the spin dephasing
time and the ensemble spin dephasing time by solving the
full microscopic kinetic spin Bloch equations, and we show that, analogous to
the common sense in an isotropic system for conduction electrons, ,
and are identical due to the short correlation time. The
inhomogeneous broadening induced by the D'yakonov-Perel term is suppressed by
the scattering, especially the Coulomb scattering, in this system.Comment: 4 pages, 2 figures, to be published in Phys. Lett.
Levantamento das patologias e monitorização do Arco-Cruzeiro da Igreja da Misericórdia de Aveiro
O estado de conservação das construções tradicionais motiva para um crescente interesse na recuperação e manutenção do património construído. Antes de mais, é importante obter uma visão geral da evolução temporal das construções permitindo assim a caracterização dos diversos aspectos estruturais e construtivos. Este trabalho foi desenvolvido com o objectivo de estudar as patologias associadas à nave principal da Igreja da Misericórdia de Aveiro e em particular as patologias associadas ao Arco-Cruzeiro que se encontra no interior desta, com o intuito de se estabelecer a melhor estratégia de monitorização dos danos estruturais a aplicar. Como resultado desta análise foi proposto e implementado um plano de monitorização, com o desenvolvimento de meios de instrumentação, que permitem monitorizar o comportamento estrutural do arco, de forma não intrusiva, garantindo a reversibilidade e a eventual futura extensão da instrumentação. Foi ainda desenvolvido um modelo numérico em elementos finitos que serviu de apoio à interpretação das causas dos danos estruturais encontrados
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