1,498 research outputs found

    Production of optical phase space vortices with non-locally distributed mode converters

    Full text link
    Optical vortices have been observed in a wide variety of optical systems. They can be observed directly in the wavefront of optical beams, or in the correlations between pairs of entangled photons. We present a novel optical vortex which appears in a non-local plane of the two-photon phase space, composed of a single degree of freedom of each photon of an entangled pair. The preparation of this vortex can be viewed as a "non-local" or distributed mode converter. We show how these novel optical vortices of arbitrary order can be prepared in the spatial degrees of freedom of entangled photons.Comment: To appear in upcoming special issue "Orbital Angular Momentum" of the Journal of Optic

    Single observable concurrence measurement without simultaneous copies

    Get PDF
    We present a protocol that allows us to obtain the concurrence of any two qubit pure state by performing a minimal and optimal tomography of one of the subsystems through measuring a single observable of an ancillary four dimensional qudit. An implementation for a system of trapped ions is also proposed, which can be achieved with present day experimental techniques.Comment: 4 pages, 1 figur

    Composition of Primary Cosmic Rays Beyond the ``Knee''from Emulsion Chamber Observations

    Get PDF
    We show that the simplest assumptions for the dynamics of particle production allow us to understand the fluxes of hadrons and photons at mountain altitudes as well as the structure of individual events. The analysis requires a heavy nuclear component of primary cosmic rays above the ``knee" in the spectrum with average mass number =7.3±0.9 = 7.3 \pm 0.9.Comment: Revtex, 11 pages, 5 postscript figures ("\special" command used to embed figures at end of tex file). Compressed postscript version also available at http://phenom.physics.wisc.edu/pub/preprints/1996/madph-96-932.ps.Z or ftp://phenom.physics.wisc.edu/pub/preprints/1996/madph-96-932.ps.

    Bacillus thuringiensis como agente de controle biológico.

    Get PDF
    Classes de genes cry. cry I. cry II. cry III. cry IV. cry V. Expressão dos genes cry. Modo de ação das endotoxinas. Estrutura. Solubilização e ativação. Ligação ao recptor. Formaçãode lesão tóxica. Formas de utilização das proteínas Cry. Uso direto de B. thuringiensis. Plantas transgênicas. Microrganismos transgênicos. .bitstream/CNPAB-2010/27246/1/doc054.pd

    Relationships and events: towards a general theory of reification and truthmaking.

    Get PDF
    We propose a novel ontological analysis of relations and relationships based on a re-visitation of a classic problem in the practice of knowledge repre- sentation and conceptual modeling, namely relationship reification. Our idea is that a relation holds in virtue of a relationship's existence. Relationships are therefore truthmakers of relations. In this paper we present a general theory or reification and truthmaking, and discuss the interplay between events and rela- tionships, suggesting that relationships are the focus of events, which emerge from the context (the scene) they occur in

    Influence of the anisotropic behavior on equibiaxial paths

    Get PDF
    Marciniak and Nakajima tests are commonly used in building FLD's, since they allow covering all regions from uniaxial to almost equibiaxial strain paths. In this work, the deviation from equibiaxial strain paths is analyzed as function of the material anisotropic behavior. The numerical results show that material with r0 = r90 present equibiaxial stress and strain paths, while for the ones with r0 ≠ r90 the paths are neither equibiaxial in stress nor strain. Moreover, it is shown that despite the similarities between the two tests, they present different sensitivity to the control of the blank holder force and to the friction coefficient. Namely, the stress and strain paths in the Marciniak specimen center are more sensitive to the control of the blank holder force. On the other hand, the stress and strain paths in the Nakajima specimen center are more sensitive to the friction coefficient. The deviation from the equibiaxial strain path indicates that the stress ratio is also not necessarily 1.0, meaning that the stress triaxiality and the Lode parameter also present some deviation from the reference values for an equibiaxial stress state. This should be taken into account when analyzing forming limit results.The authors gratefully acknowledge the financial support of the projects POCI-01-0145-FEDER030592 (PTDC/EME-EME/30592/2017) and UIDB/00285/2020 financed by the Operational Program for Competitiveness and Internationalization, in its FEDER/FNR component, and the Portuguese Foundation of Science and Technology (FCT), in its State Budget component (OE)

    El agua de coco(Cocus nucifera L) in natura integral y adicionada con citoquininas, como dilutor de semen caprino.

    Get PDF
    Este trabajo busca conocer el efecto de la adicion de citoquininas en el agua de coco utilizada como dilutor del semen caprino. Se evaluo in vitro el comportamiento de los espermatozoides colectados con vagina artificial de cuatro machos caprinos, diluidos en agua de coco in natura integral y adicionada con 5 o 100mg de zeatina, una citoquinina natural. Se aplico una prueba de termorresistencia, incubando los espermatozoides a 37 graus C entre 0 y 120 minutos. Se observo un considerable incremento de la motilidad individual progressiva y del porcentaje de los espermatozoides motiles a los 60 minutos, especialmente con la menor dilucion. Estos resultados deberan ser correlacionados con la fertilidad in vivo luego de la inseminacion artificial

    Revisões em micorriza I: Técnicas moleculares aplicadas ao estudo dos fungos micorrízicos arbusculares.

    Get PDF
    Caracterização de esporos de FMA. Extração DNA a partir de amostras de FMA. Técnicas moleculares empregadas no estudo de FMA. Detecção e identificação de FMA. Filogenia. Protocolos. Extração de DNA a partir de esporos de FMA. A partir de um esporo (LIoyd-Macglip et al., 1996). De 10 a 20 esporos. A partir de 50 esporos (LIoyd-Macglip et al., 1996). partir de micélio (longato e bonfante, 1997. Extração de DNA bde raízes colonizadas por FMA ( Abbas et al., 1996)bitstream/CNPAB-2010/27263/1/doc068.pd

    Embryo transfer from seropositive goats for caprine arthritis-encephalitis virus (CAEV) with birth of seronegative kid.

    Get PDF
    Abstract: The aim of this study was to determine whether recipient goats would seroconvert following transfer of embryos collected from donor goats seropositive for CAEV and if kids produced would be clinically normal and seronegative for CAEV. Four does (Saanen and Alpine), seropositive for CAEV, were used as donors, receiving superovulation treatment consisting of progestagen, cloprostenol and FSH. During estrus the donors were mated with seropositive bucks. Seven days after estrus, embryo recovery was performed by surgery. The embryos were then frozen according to the protocol of the International Embryo Transfer Society (IETS). Twelve seronegative does were used as recipients and received an estrus synchronization treatment consisting of progestagen, cloprostenol and eCG. Embryo transfer was performed seven days after synchronized estrus using the semilaparoscopy technique. Pregnancy was verified in one of twelve recipients, that remained seronegative until six months after giving birth and the kid until six months of age. The preliminary success in producing CAEV negative kids and failure of seroconversion in previously seronegative recipients in this study suggests that embryo transfer technology may offer an alternative in the prevention of CAEV transmission in goat herds as well for the utilization of genetic patrimony of seropositive goats. [Transferência de embriões de cabras soropositivas para artrite-encefalite caprina a vírus (CAEV) com nascimento de cria soronegativa]. Resumo: O objetivo deste estudo foi verificar se cabras receptoras sofreriam soroconversão após a transferência de embriões colhidos de cabras soropositivas e se as crias nascidas seriam clinicamente normais e soronegativas para CAEV. Foram utilizadas quatro cabras (Saanen e Alpina), todas soropositivas para CAEV e que receberam um tratamento superovulatório que consistiu no uso de progestágeno, cloprostenol e FSH. Durante o estro, as doadoras foram cobertas por bodes soropositivos. Sete dias após o estro, a colheita de embriões foi realizada utilizando a técnica cirúrgica. Os embriões colhidos foram congelados de acordo com o protocolo da Sociedade Internacional de Transferência de Embriões (IETS). Doze cabras soronegativas foram utilizadas como receptoras e receberam um tratamento de sincronização do estro consistindo de progestágeno, cloprostenol e eCG. A transferência de embriões foi realizada sete dias após o estro sincronizado usando a técnica de semi-laparoscopia. A gestação foi confirmada em uma das doze receptoras, a qual permaneceu soronegativa até seis meses após o parto e sua cria até os seis meses de idade. O sucesso preliminar na produção de crias soronegativas para CAEV e a não soroconversão em receptoras soronegativas sugere que a tecnologia de transferência de embriões pode oferecer uma alternativa para a profilaxia da CAEV em rebanhos caprinos, bem como para o aproveitamento do patrimônio genético de animais soropositivos
    corecore