1,266 research outputs found
Diversidade, preferência alimentar e distribuição vertical de Tripes (Thysanoptera : Thripidae) em mangueira, no semi-árido nordestino.
Este trabalho teve como objetivos: conhecer a diversidade, as estruturas vegetaispreferidas e a distribuição vertical dos tripes na mangueira.1 CD-ROM
Screening in Anyon Gas
Anyon gas with interparticle (retarded) Coulomb interaction has been studied.
The resulting system is shown to be a collection of dressed anyons, with a
screening factor introduced in their spin. Close structural similarity with the
Chern-Simons construction of anyons has helped considerably in computing the
screening effect. Finally the present model is compared with the conventional
Chern-Simons construction.Comment: 10 pages Late
On the General Analytical Solution of the Kinematic Cosserat Equations
Based on a Lie symmetry analysis, we construct a closed form solution to the
kinematic part of the (partial differential) Cosserat equations describing the
mechanical behavior of elastic rods. The solution depends on two arbitrary
analytical vector functions and is analytical everywhere except a certain
domain of the independent variables in which one of the arbitrary vector
functions satisfies a simple explicitly given algebraic relation. As our main
theoretical result, in addition to the construction of the solution, we proof
its generality. Based on this observation, a hybrid semi-analytical solver for
highly viscous two-way coupled fluid-rod problems is developed which allows for
the interactive high-fidelity simulations of flagellated microswimmers as a
result of a substantial reduction of the numerical stiffness.Comment: 14 pages, 3 figure
Espécies de Frankliniella (Thysanoptera, Thripidae): novos registros em mangueira (Mangifera indica) no Brasil.
O objetivo do trabalho foi conhecer as espécies de tripes (Thysanoptera) que atacam pomares de mangueira no semiárido pernambucano. Foram realizadas coletas no período de um ano, em três plantios comerciais da cv. ?Tommy Atkins?. Avaliações semanais foram realizadas em 75 plantas, nos estádios vegetativo e reprodutivo, perfazendo um total de 10.704 amostras em folhas e 390 em panículas. Os espécimes coletados foram levados ao laboratório da Embrapa Semiárido, Petrolina, PE, para triagem dos adultos em microscópio estereoscópico e, posteriormente, enviados à Universidade Federal de Lavras, MG, para identificação. As espécies Frankliniella gardeniae Moulton e Frankliniella Brevicaulis Hood, pertencentes à família Thripidae, representaram, respectivamente, 77% e 23% do total dos tripes coletados. Este estudo relata a primeira ocorrência dessas duas espécies em associação à cultura da mangueira, no Brasil
Evidence of suppression of onchocerciasis transmission in the Venezuelan Amazonian focus.
BACKGROUND: The World Health Organization (WHO) has set goals for onchocerciasis elimination in Latin America by 2015. Most of the six previously endemic countries are attaining this goal by implementing twice a year (and in some foci, quarterly) mass ivermectin (Mectizan®) distribution. Elimination of transmission has been verified in Colombia, Ecuador and Mexico. Challenges remain in the Amazonian focus straddling Venezuela and Brazil, where the disease affects the hard-to-reach Yanomami indigenous population. We provide evidence of suppression of Onchocerca volvulus transmission by Simulium guianense s.l. in 16 previously hyperendemic Yanomami communities in southern Venezuela after 15 years of 6-monthly and 5 years of 3-monthly mass ivermectin treatment. METHODS: Baseline and monitoring and evaluation parasitological, ophthalmological, entomological and serological surveys were conducted in selected sentinel and extra-sentinel communities of the focus throughout the implementation of the programme. RESULTS: From 2010 to 2012–2015, clinico-parasitological surveys indicate a substantial decrease in skin microfilarial prevalence and intensity of infection; accompanied by no evidence (or very low prevalence and intensity) of ocular microfilariae in the examined population. Of a total of 51,341 S. guianense flies tested by PCR none had L3 infection (heads only). Prevalence of infective flies and seasonal transmission potentials in 2012–2013 were, respectively, under 1 % and 20 L3/person/transmission season. Serology in children aged 1–10 years demonstrated that although 26 out of 396 (7 %) individuals still had Ov-16 antibodies, only 4/218 (2 %) seropositives were aged 1–5 years. CONCLUSIONS: We report evidence of recent transmission and morbidity suppression in some communities of the focus representing 75 % of the Yanomami population and 70 % of all known communities. We conclude that onchocerciasis transmission could be feasibly interrupted in the Venezuelan Amazonian focus. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13071-016-1313-z) contains supplementary material, which is available to authorized users
Millisecond-range electron spin memory in singly-charged InP quantum dots
We report millisecond-range spin memory of resident electrons in an ensemble
of InP quantum dots (QDs) under a small magnetic field of 0.1 T applied along
the optical excitation axis at temperatures up to about 5 K. A pump-probe
photoluminescence (PL) technique is used for optical orientation of electron
spins by the pump pulses and for study of spin relaxation over the long time
scale by measuring the degree of circular polarization of the probe PL as a
function of pump-probe delay. Dependence of spin decay rate on magnetic field
and temperature suggests two-phonon processes as the dominant spin relaxation
mechanism in this QDs at low temperatures.Comment: 3 pages, 4 figures, submitted to Appl. Phys. Let
Social Role in Organizational Management - Understanding People Behavior and Motivation
The aim of this work is to respond to the need to rethink the behavior and motiva-tion of employees in their relationship with managers and social groups, i.e., one`s main goal is based on increasing engagement in order to reach organiza-tional goals and job workers satisfaction, a complex concept that is influenced by different causes. Indeed, in this work it is analyzed the impact of working condi-tions on job satisfaction. This is where attention is drawn to the concept of entro-py, since we are not focusing on the value a variable can take, but on the effort that has been expended to obtain it. The idea of entropy comes from a principle of thermodynamics dealing with energy. It usually refers to the idea that everything in the universe eventually moves from order to disorder, and entropy is the meas-urement of that change, that is used here to understand and assess the workers behavior and motivation. The subsequent formal model is based on a set of logi-cal structures for knowledge representation and reasoning that conform to the above entropic view, then leading to an Artificial Neural Network approach to computation, an archetypal that considers the motive behind the action
Bounding Anomalous Gauge-Boson Couplings
In this version we have corrected some minor errors in the tables, corrected
typos, and added a reference. We have also updated our comparison with earlier
workers. Figures are now included as uuencoded compressed tar files.Comment: 32 page
Probing Single-Electron Spin Decoherence in Quantum Dots using Charged Excitons
We propose to use optical detection of magnetic resonance (ODMR) to measure
the decoherence time T_{2} of a single electron spin in a semiconductor quantum
dot. The electron is in one of the spin 1/2 states and a circularly polarized
laser can only create an optical excitation for one of the electron spin states
due to Pauli blocking. An applied electron spin resonance (ESR) field leads to
Rabi spin flips and thus to a modulation of the photoluminescence or,
alternatively, of the photocurrent. This allows one to measure the ESR
linewidth and the coherent Rabi oscillations, from which the electron spin
decoherence can be determined. We study different possible schemes for such an
ODMR setup, including cw or pulsed laser excitation.Comment: 8 pages, 7 figures. Proceedings of the PASPS3 conference, Santa
Barbara, CA (USA). To appear in the Journal of Superconductivit
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