Dinâmica populacional do ácaro verde Mononychellus planki em cultivares de soja.

bitstream/item/71543/1/ID-30978.pd

Magnetization plateau in a two-dimensional multiple-spin exchange model

We study a multiple-spin exchange model on a triangular lattice, which is a possible model for low-density solid 3He films. Due to strong competitions between ferromagnetic three-spin exchange and antiferromagnetic four-spin one, the ground states are highly degenerate in the classical limit. At least 2^{L/2}-fold degeneracy exists on the L*L triangular lattice except for the SO(3) symmetry. In the magnetization process, we found a plateau at m/m_{sat}=1/2, in which the ground state is "uuud state" (a collinear state with four sublattices). The 1/2-plateau appears due to the strong four-spin exchange interaction. This plateau survives against both quantum and thermal fluctuations. Under a magnetic field which realizes the "uuud" ordered state, a phase transition occurs at a finite temperature. We predict that low-density solid 3He thin films may show the 1/2-plateau in the magnetization process. Experimental observation of the plateau will verify strength of the four-spin exchange. It is also discussed that this magnetization plateau can be understood as an insulating-conducting transition in a particle picture.Comment: 10 pages, RevTeX, 12 figures, added a reference and corrected typos, to be published in Phys.Rev.B (01 APR 99

Regressão linear para predição do estado nutricional de bananeiras tipo prata.

A avaliação do estado nutricional de bananeiras é fundamental para recomendação de adubação e manejo da cultura. Diversos métodos analíticos são utilizados, mas a segurança dos dados e a demora para a obtenção dos resultados dificulta a tomada de decisão que favorece o aparecimento de sintomas de deficiência e consequente queda de produtividade da lavoura

Análise das frequências alélicas e genotípicas de polimorfismos nos genes da calpaína e da calpastatina em bovinos de corte.

Trabalho 1

Water use efficiency in bananas pome type cropsusing empirical coefficient based on leaf area.

The aim of this work was to evaluate the yield and water use efficiency (WUE) of banana ?Prata-Anã? (AAB) and ?BRS Platina? (AAAB) during two cycles of production in a semi-arid climate of Brazil (classified as Aw according Köppen)

Effect of agrochemicals on the pattern of visitation of honey bees (Apis mellifera) in melon (Cucumis melo) flowers in Brazilian Northeast.

Edição dos Proceedings of the 11 International Symposium Hazards of Pesticides to Bees, Wageningen, nov. 2011

Multicentre investigation of neutron contamination at cardiac implantable electronic device (CIED) location due to high-energy photon beams using passive detectors and Monte Carlo simulations

Radiotherapy treatments involving LINACs operating at accelerating potentials >10 MV generate (photo)neutrons which deliver dose to patients also outside the target volume. This effect is particularly relevant for patients with cardiac implantable electronic devices (CIEDs), which can be damaged by the therapeutic irradiation. In the last few years, there has been a rising interest in this issue, and it seems that damage to CIEDs is primarily associated with the thermal component of the photoneutron field. In particular, a recent study led by Politecnico di Milano considered CIEDs from various manufacturers and showed that some of these devices can be damaged after an irradiation with a thermal neutron fluence of about 10^9 cm^-2. The present work results from a collaboration among Politecnico di Milano, the University of Pisa, the University of Trieste and three Italian hospitals located in Lucca, Trieste and Varese, respectively, and it is primarily aimed at evaluating the thermal neutron fluence in CIED region for some high-energy treatments delivered at 15 and 18 MV and to determine whether it is comparable to the critical value given above, which has been experimentally determined to be potentially harmful for CIEDs. Thermal neutron fluence was measured through CR-39 detectors and TLDs, which were housed inside a BOMAB-like phantom mimicking the patient’s trunk. The experimental sessions involved two models of LINAC, Varian Clinac DHX (Varese hospital) and Elekta Synergy (Lucca and Trieste hospitals). The experimental results show that the treatments considered in this study can lead to a thermal neutron fluence in the cardiac region comparable to the critical value. Furthermore, detailed Monte Carlo geometries for the facilities involved in this project were developed with the MCNP code (v. 6.2), and they were tested by comparing simulation results to measurements considering some benchmark irradiation plans. Bubble detectors were also employed for fast neutron fluence measurements to be compared to simulation outputs. These computational models stand out as promising tools for the investigations required in this work, and they can be used for further studies also extending their use to analogous facilities hosting the same models of LINACs

Avaliação do polimorfismo CAST/Xmnl em bovinos de corte.

A utilização de testes de DNA para a identificação precoce de animais que apresentam potencial para produção de carne bovina de qualidade constitui uma importante ferramenta para viabilizar a seleção dos reprodutores e aumentar a qualidade da carne do rebanho comercial. Outro fator que contribui para o aumento da qualidade da carne são os cruzamentos utilizando raças das subespécies Bos taurus indicus e Bos taurus taurus, pois sabe-se que quanto maior a proporção de sangue zebuíno no rebanho, menores são os valores de maciez encontrados. Até o momento, vários genes relacionados com essa característica foram identificados, sendo um deles o gene CAST, que codifica a enzima calpastatina. Neste contexto, o objetivo deste trabalho foi avaliar as frequências alélicas e genotípicas do polimorfismo CAST/XmnI nas raças Bonsmara, Caracu e Senepol (taurinas adaptadas), Nelore (zebuína) e Angus (taurina não adaptada), visando orientar a escolha de uma raça taurina adaptada para produção de carne de qualidade em sistemas de cruzamento. Para a extração do DNA, foram obtidas amostras de sêmen e de sangue de 111 touros escolhidos de acordo com a genealogia e com o menor grau de parentesco possível. A genotipagem foi realizada pela técnica PCR-RFLP e as frequências alélicas e genotípicas foram comparadas utilizando o teste de Qui-quadrado. Houve diferença significativa nas frequências alélicas e genotípicas entre as raças (p<0,05), sendo que as raças Angus e Bonsmara apresentaram os maiores valores de frequência para o alelo A (88,6%). A raça Nelore foi a que apresentou maior frequência para o alelo B (54,2%), seguida pela Caracu (36,4%) e pela Senepol (28,6%). Esse marcador mostrou-se viável para seleção de bovinos, já que a alta frequência do alelo A, observada na população em estudo, permite que o teste seja aplicado, desde que confirmada a associação desse polimorfismo com a maciez da carne