428 research outputs found

    Coherent states of non-relativistic electron in magnetic-solenoid field

    Full text link
    We construct coherent states of a nonrelativistic electron in the magnetic-solenoid field, which is a superposition of the Aharonov-Bohm field and a collinear uniform magnetic field. In the problem under consideration there are two kind of coherent states, the first kind corresponds to classical trajectories which embrace the solenoid and the second one to trajectories which do not. Mean coordinates in the constructed coherent states are moving along classical trajectories, the coherent states maintain their form under the time evolution, and represent a complete set of functions, which can be useful in semi classical calculations. In the absence of the Aharonov-Bohm filed these states are reduced to the well-known in the case of uniform magnetic field Malkin-Man'ko coherent states.Comment: 11 pages, version accepted for publication in J. Phys. A, 3 figures adde

    Preparação de dados para a modelagem de ocorrências da ferrugem asiática da soja.

    Get PDF
    A ferrugem asiática da soja é uma das principais doenças da cultura. As perdas estimadas em grãos com a doença no Brasil são significativas. O objetivo deste trabalho foi realizar a preparação dos dados para a modelagem de ocorrências da ferrugem asiática, visando descobrir padrões que permitam predizer o risco do aparecimento de focos da doença. Os dados brutos se constituíram de registros de ocorrência da ferrugem em diferentes locais do Brasil, de 2004 a 2009, obtidos do Consórcio Antiferrugem, e de registros meteorológicos da base de dados do Agritempo. A integração dos dados meteorológicos com os registros de ocorrência foi feita com base no período latente do patógeno. Atributos novos foram criados, enquanto outros foram eliminados, por irrelevância ou por falta de dados. A tarefa de mineração de dados escolhida inicialmente foi a classificação, e os casos de ocorrência da ferrugem definiram a classe positiva. Os casos da classe negativa foram criados para uma data anterior à de ocorrência da ferrugem, supondo-se não ter havido ocorrência antes da identificação confirmada. A preparação dos dados resultou no conjunto de treinamento para a modelagem com 7076 exemplos, divididos igualmente em 3038 casos de ocorrência e de não ocorrência. O número de ocorrências diminuiu bastante em relação à quantidade original, por falta de dados meteorológicos para vários dos locais de identificação, mas não inviabiliza a iniciativa de descoberta de conhecimento em bases de dados proposta.SBIAgro 2009

    Incidência e danos da broca-do-pinhão, Cydia araucariae (Pastrana), em sementes de araucária.

    Get PDF
    bitstream/item/39830/1/CT276.pd

    Incidência e danos da broca-das-meliáceas, Hypsipyla grandella, em mogno, no interior paulista.

    Get PDF
    bitstream/item/39888/1/CT280.pd

    Optimization of Au:CuO thin films by plasma surface modification for high-resolution LSPR gas sensing at room temperature

    Get PDF
    In this study, thin films composed of gold nanoparticles embedded in a copper oxide matrix (Au:CuO), manifesting Localized Surface Plasmon Resonance (LSPR) behavior, were produced by reactive DC magnetron sputtering and post-deposition in-air annealing. The effect of low-power Ar plasma etching on the surface properties of the plasmonic thin films was studied, envisaging its optimization as gas sensors. Thus, this work pretends to attain the maximum sensing response of the thin film system and to demonstrate its potential as a gas sensor. The results show that as Ar plasma treatment time increases, the host CuO matrix is etched while Au nanoparticles are uncovered, which leads to an enhancement of the sensitivity until a certain limit. Above such a time limit for plasma treatment, the CuO bonds are broken, and oxygen is removed from the film’s surface, resulting in a decrease in the gas sensing capabilities. Hence, the importance of the host matrix for the design of the LSPR sensor is also demonstrated. CuO not only provides stability and protection to the Au NPs but also promotes interactions between the thin film’s surface and the tested gases, thereby improving the nanocomposite film’s sensitivity. The optimized sensor sensitivity was estimated at 849 nm/RIU, which demonstrates that the Au-CuO thin films have the potential to be used as an LSPR platform for gas sensors.This research was sponsored by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/04650/2020 and by the project CO2Plasmon with reference EXPL/CTM-REF/0750/2021. M.P. acknowledges her Ph.D. Scholarship from FCT, with reference SFRH/BD/137076/2018. Diana I. Meira acknowledges her Ph.D. Scholarship from FCT, with reference SFRH/BD/143262/2019

    A genome-wide association study for morphometric traits in quarter horse

    Get PDF
    A genome-wide association study for morphometric traits was conducted in 184 Quarter Horses, 120 from a racing population, and 64 from a cutting population, which were genotyped using the Illumina EquineSNP50 chip. Association analysis was performed with 42,058 single-nucleotide polymorphisms (SNPs) (after quality control) using Qxpak5 software. The following traits were measured: weight (W), rump length (RL), and body length (BL). These morphometric traits are important for the best performance in race and cutting events. For weight, three SNPs associated (P < .0001) were found on chromosomes (Equus caballus autosomes [ECA]) 2 and 3. For rump length, eight SNPs associated (P < .0001) were found on ECA 2, 3, 6, 7, 9, 21, and 26. On ECA 3 and ECA 8, two SNPs were associated (P < .0001) with body length. So, a total of 13 important chromosomal regions were identified with Q values of 0.53 (SNPs for W), 0.40 (SNPs for RL), and 0.99 (SNPs for BL). Positional and functional candidate genes emerging from this study were WWOX and AAVPR1A. Further studies are required to confirm these associations in other populations. (c) 2014 Elsevier Inc. All rights reserved

    Chitosan micro-membranes with integrated gold nanoparticles as an LSPR-based sensing platform

    Get PDF
    Currently, there is an increasing need to develop highly sensitive plasmonic sensors able to provide good biocompatibility, flexibility, and optical stability to detect low levels of analytes in biological media. In this study, gold nanoparticles (Au NPs) were dispersed into chitosan membranes by spin coating. It has been demonstrated that these membranes are particularly stable and can be successfully employed as versatile plasmonic platforms for molecular sensing. The optical response of the chitosan/Au NPs interfaces and their capability to sense the medium’s refractive index (RI) changes, either in a liquid or gas media, were investigated by high-resolution localized surface plasmon resonance (HR-LSPR) spectroscopy, as a proof of concept for biosensing applications. The results revealed that the lowest polymer concentration (chitosan (0.5%)/Au-NPs membrane) presented the most suitable plasmonic response. An LSPR band redshift was observed as the RI of the surrounding media was incremented, resulting in a sensitivity value of 28 ± 1 nm/RIU. Furthermore, the plasmonic membrane showed an outstanding performance when tested in gaseous atmospheres, being capable of distinguishing inert gases with only a 10−5 RI unit difference. The potential of chitosan/Au-NPs membranes was confirmed for application in LSPR-based sensing applications, despite the fact that further materials optimization should be performed to enhance sensitivity.This research was sponsored by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/04650/2020, by the project CO2Plasmon with reference EXPL/CTM-REF/0750/2021 and by the project with reference PTDC/CTM-CTM/2846/2020. Diana I. Meira acknowledges her Ph.D. Scholarship from FCT, with reference SFRH/BD/143262/2019. Manuela Proença acknowledges her Ph.D. Scholarship from FCT, with reference SFRH/BD/137076/2018

    Identification of morphofunctional traits in Mangalarga Marchador horse using principal component analysis

    Get PDF
    Dados de 14.288 animais da ra?a Mangalarga Marchador, nascidos de 1990 a 2005, foram utilizados para avaliar a redu??o da dimensionalidade do espa?o multivariado para caracter?sticas morfofuncionais, por meio da an?lise de componentes principais. Foram consideradas as caracter?sticas: altura na cernelha, altura na garupa, comprimento da cabe?a, comprimento do pesco?o, comprimento do dorso, comprimento da garupa, comprimento da esp?dua, comprimento do corpo, largura da cabe?a, largura das ancas, per?metro do t?rax, per?metro da canela e a pontua??o da marcha. Para tais caracter?sticas, obtiveram-se sete componentes principais, a partir da matriz de correla??o, que apresentaram vari?ncia inferior a 0,7 (autovalor inferior a 0,7). Isso sugere sete vari?veis para descarte, por apresentarem maiores coeficientes de pondera??o, em valor absoluto, a partir do ?ltimo componente principal. A raz?o para isso ? que vari?veis altamente correlacionadas com os componentes de menor vari?ncia representam varia??o praticamente insignificante. Com base nesses resultados, recomendam-se as seguintes caracter?sticas para serem mantidas em trabalhos futuros com esta base de dados: pontua??o da marcha, altura na garupa, comprimento do dorso, comprimento da garupa, largura da cabe?a e per?metro da canela.Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG)Empresa de Pesquisa Agropecu?ria de Minas Gerais (EPAMIG)Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)Records from 14,288 animals of the Mangalarga Marchador breed, born from 1990 to 2005, were used to discard morphofunctional traits in a principal component analysis. The following traits were used: height at withers, height at croup, lengths of head, neck, back, croup, hip length and body, widths of head, hip width, thorax perimeter, cannon bone circumference and gait score. For the traits considered it was observed that 7 principal components showed variation lower than 0.7; suggesting that seven variables could be discarded. The reason is that when variable are highly correlated with the principal components of smaller variance, their variation is practically insignificant. Based on those results the recommendation is to maintain the following traits for future research with this database: gait score, height at croup, length of back, length of croup, width of head and cannon bone circumference

    Crescimento de mudas de Triplaris americana em função do substrato e da adubação.

    Get PDF
    Editado por: Igor Rodrigues de Assis; Tema do fórum: Áreas degradadas e recurso do solo
    corecore