11,874 research outputs found

    Description and molecular phylogeny of a new and one known needle nematode of the genus Paralongidorus (Nematoda: Longidoridae) from grapevine in Portugal

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    A new and a known longidorid nematode, Paralongidorus lusitanicus n. sp. and Paralongidorus plesioepimikis, are described and illustrated from populations extracted from soil associated with grapevine (Vitis vinifera L.) from Escaroupim and Pó (central-Western Portugal), respectively. The new needle nematode P. lusitanicus n. sp. is characterised by a very large body size (8072–12,022 μm), an expanded and rounded lip region, ca 30 μm wide, with a clear constriction followed by a depression posterior to the amphidial aperture, amphidial fovea very large (11.0–19.0 μm), stirrup-shaped, with conspicuous slit-like aperture as shown in scanning electron microscopy studies, a very long and flexible odontostyle (180.0–223.0 μm), guiding ring located at 28.0–41.5 μm from anterior end, vulva anterior to the mid-body (34–41%), a dorsally convex-conoid tail with rounded terminus (29–42 μm long), bearing two or three pairs of caudal pores and males common (ratio 1:1.6 females) with spicules ca 80 μm long. Morphological and morphometric traits for P. plesioepimikis fit well with the original description, and is reported for the first time in Portugal. Integrative diagnosis of both species was completed with molecular data obtained using D2-D3 expansion segments of 28S rDNA, ITS1-rDNA and partial 18S–rDNA. The phylogenetic relationships of these species with other Paralongidorus spp. using these three molecular markers indicated that P. lusitanicus n. sp. clustered together with other Paralongidorus spp. forming a sister clade with P. plesioepimikis, both of them sharing a large body, long odontostyle, an anteriorly located vulva and an expanded and rounded lip region with a clear constriction followed by a depression posterior to the amphidial aperture

    Explosion of white dwarfs harboring hybrid CONe cores

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    Recently, it has been found that off-centre carbon burning in a subset of intermediate-mass stars does not propagate all the way to the center, resulting in a class of hybrid CONe cores. Here, we consider the possibility that stars hosting these hybrid CONe cores might belong to a close binary system and, eventually, become white dwarfs accreting from a non-degenerate companion at rates leading to a supernova explosion. We have computed the hydrodynamical phase of the explosion of Chandrasekhar-mass white dwarfs harboring hybrid cores, assuming that the explosion starts at the center, either as a detonation (as may be expected in some degenerate merging scenarios) or as a deflagration (that afterwards transitions into a delayed detonation). We assume these hybrid cores are made of a central CO volume, of mass M(CO), surrounded by an ONe shell. We show that, in case of a pure detonation, a medium-sized CO-rich region, M(CO)<0.4 Msun, results in the ejection of a small fraction of the mantle while leaving a massive bound remnant. Part of this remnant is made of the products of the detonation, Fe-group nuclei, but they are buried in its inner regions, unless convection is activated during the ensuing cooling and shrinking phase of the remnant. In contrast, and somehow paradoxically, delayed detonations do not leave remnants but for the minimum M(CO) we have explored, M(CO)=0.2 Msun, and even in this case the remnant is as small as 0.13 Msun. The ejecta produced by these delayed detonations are characterized by slightly smaller masses of 56Ni and substantially smaller kinetic energies than obtained for a delayed detonation of a 'normal' CO white dwarf. The optical emission expected from these explosions would hardly match the observational properties of typical Type Ia supernovae, although they make interesting candidates for the subluminous class of SN2002cx-like or SNIax.Comment: Accepted for Astronomy and Astrophysics, 11 pages, 4 figure

    Anderson Localization in Disordered Vibrating Rods

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    We study, both experimentally and numerically, the Anderson localization phenomenon in torsional waves of a disordered elastic rod, which consists of a cylinder with randomly spaced notches. We find that the normal-mode wave amplitudes are exponentially localized as occurs in disordered solids. The localization length is measured using these wave amplitudes and it is shown to decrease as a function of frequency. The normal-mode spectrum is also measured as well as computed, so its level statistics can be analyzed. Fitting the nearest-neighbor spacing distribution a level repulsion parameter is defined that also varies with frequency. The localization length can then be expressed as a function of the repulsion parameter. There exists a range in which the localization length is a linear function of the repulsion parameter, which is consistent with Random Matrix Theory. However, at low values of the repulsion parameter the linear dependence does not hold.Comment: 10 pages, 6 figure

    Improvement plan for unification of protocols into Agricultural Research Laboratories.

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    El termino protocolo se viene utilizando para designar al conjunto de acciones que deben realizarse ante situaciones determinadas con el fin de normalizar la actuación de las personas que las ejecutan. En términos generales, se utiliza en algunos casos como procedimiento y en otros, su uso no se limita para describir las acciones y recursos detallados cronológicamente, sino de manera más amplia, al conjunto de normas, procedimientos y registros que se deben llevar a cabo ante una situación prefijada de antemano. En todos los protocolos se incluye además, la descripción del personal necesario para desarrollarlo y la función específica dentro del mismo, estos deben ser revisados y actualizados permanentemente para que el sistema se mantenga y se mejore continuamente. Este trabajo se enfocó en la elaboración de un plan de mejoramiento para la unificación de los protocolos existentes en los laboratorios de investigación de una entidad pública agropecuaria, el impacto que ha logrado en la organización es una base para el control y mantenimiento de un modelo organizado para todo el personal que lo utiliza, al tener una fuente de referencia única y fiable para sus actuaciones. Es vital importancia hacer una continua evaluación de los indicadores y los planes de contingencia en caso del no cumplimiento de las metas propuestas.The term protocol has been used to refer to the set of actions to take in certain situations in order to standardize the conduct of the people that run them. In general, it is used in some cases and in other proceedings, its use is not limited to describe the actions and detailed chronologically but more broadly resources, set of rules, procedures and records that must be held before default situation beforehand. In all protocols is also included, the description of the personnel needed to develop and the specific role within it, they must be constantly reviewed and updated so that the system is maintained and continually improved. This work focused on the development of an improvement plan for the unification of existing protocols in the research laboratories of agricultural public entity, the impact it has made in the organization is a basis for monitoring and maintaining an organized model for all staff to use it, to have a single, reliable source of reference for their actions. It is vital to make a continuous assessment of the indicators and contingency plans in case of non-compliance with the goals

    The Triple Higgs Boson Self-Coupling at Future Linear e+e- Colliders Energies: ILC and CLIC

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    We analyzed the triple Higgs boson self-coupling at future e+e−e^{+}e^{-} colliders energies, with the reactions e+e−→bbˉHH,ttˉHHe^{+}e^{-}\to b \bar b HH, t \bar t HH. We evaluate the total cross-sections for both bbˉHHb\bar bHH and ttˉHHt\bar tHH, and calculate the total number of events considering the complete set of Feynman diagrams at tree-level. We vary the triple coupling κλ3H\kappa\lambda_{3H} within the range κ=−1\kappa=-1 and +2. The numerical computation is done for the energies expected to be available at a possible Future Linear e+e−e^{+}e^{-} Collider with a center-of-mass energy 800,1000,1500800, 1000, 1500 GeVGeV and a luminosity 1000 fb−1fb^{-1}. Our analysis is also extended to a center-of-mass energy 3 TeVTeV and luminosities of 1000 fb−1fb^{-1} and 5000 fb−1fb^{-1}. We found that for the process e+e−→bbˉHHe^{+}e^{-}\to b \bar b HH, the complete calculation differs only by 3% from the approximate calculation e+e−→ZHH(Z→bbˉ)e^{+}e^{-}\to ZHH(Z\to b\bar b), while for the process e+e−→ttˉHHe^{+}e^{-}\to t \bar tHH, the expected number of events, considering the decay products of both tt and HH, is not enough to obtain an accurate determination of the triple Higgs boson self-coupling.Comment: 19 pages, 12 figure
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