1,217 research outputs found

    Conicoid Mirrors

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    The first order equation relating object and image location for a mirror of arbitrary conic-sectional shape is derived. It is also shown that the parabolic reflecting surface is the only one free of aberration and only in the limiting case of distant sources.Comment: 9 page

    Thidiazuron-induced shoot organogenesis of Cleome viscosa (L) through cotyledonary explants culture

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    A reproducible protocol for direct shoot organogenesis of Cleome viscosa, an important medicinal weed herb was developed. The seed explants were collected primarily from field grown mature plants for in vitro germination on different strength of MS basal medium with or without selection of GA3 at various concentration (0.1 to 1.0 mg/L). The highest rate of seed germination (55.3%) was noticed on full strength MS basal medium fortified with 0.5 mg/L GA3 after 30 days of culture. The excised 7 to 10 days old cotyledonary leaf, cotyledonary node and hypocotyls explants cultured on MS medium fortified with different concentration of individual cytokinin (BA/KIN/TDZ) alone or BA+KIN or TDZ+KIN or TDZ in  combinations with different auxins (IBA/NAA/IAA) influenced the frequency of adventitious microshoot formation. The rate of shoot multiplication was greatest (100%) in cotyledonary leaf explants cultured on 3.0 mg/L TDZ and 0.3 mg/L IBA tested medium after 45 days of culture. The individual microshoots were elongated well in 0.3 mg/L TDZ and 0.1 mg/L GA3 treated medium, but more number of adventitious micro roots were developed on half strength MS medium fortified with 0.1 mg/L NAA. The regenerated healthy plants were hardened in pots containing soil mix and well established into complete state similar to that of field grown plants under greenhouse condition.Keywords: Cleome viscosa L, medicinal weed plant, shoot multiplication, direct organogenesisAfrican Journal of Biotechnology, Vol. 13(9), pp. 1027-1036, 26 February, 201

    Optimization of the Position of the CR-39 Polycarbonate Sheet Inside the Solid State Track Detector “Measuring Device” Through Computational Fluid Dynamics Technique

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    The “measuring device” is one of the most reliable, efficient and economic indoor radon dosimeters that exist. This device was developed by the Proyecto de Aplicaciones de la Dosimetría (PAD) at the Physics Institute of UNAM (IF-UNAM) and consists of a transparent rigid plastic cup, a CR-39 polycarbonate sheet and a standard size metal clip that is used to hold the polycarbonate in the center of the cup. The cup is wrapped and covered with a low-density polyurethane protector in order to prevent the detector from being irradiated by ionizing particles found in the environment. In this work, an analysis was carried out that allowed to understand how the radon concentration on the polycarbonate sheet varies when its height is changed with respect to the base of the plastic cup, in order to understand what position increase the probability of interaction between radon and the surface of the detector. For the development of this work, four computational simulations were performed with the technique called Computational Fluid Dynamics (CFD). The results shows that as the CR-39 is positioned more closed to the base of the cup, the probability of interaction of the radon and the detector increase. Based on these results it is concluded that, when there is a limit in the time in which a measuring device can be placed in the zone where it is desired to quantify indoor radon, it is recommended to collocated the CR-39 at 1 cm with respect to the base of the cup

    La funcionalidad de los óxidos de hierro

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    Miocarditis aguda: diagnóstico mediante resonancia magnética cardiaca

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    Cardiomyopathies are a common cause of morbidity and mortality. Myocarditis, which is included among specific cardiomyopathies, frequently presents non-specific clinical manifestations and thus may be difficult to diagnose, or even be misdiagnosed. Traditionally employed diagnostic techniques, including endomyocardial biopsy, have been shown to be of limited value. Following its overall implantation in clinical practice, cardiac magnetic resonance imaging (MRI) is nowadays widely considered to be the best non-invasive diagnostic tool available for diagnosing myocarditi

    Resonance Patterns of an Antidot Cluster: From Classical to Quantum Ballistics

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    We explain the experimentally observed Aharonov-Bohm (AB) resonance patterns of an antidot cluster by means of quantum and classical simulations and Feynman path integral theory. We demonstrate that the observed behavior of the AB period signals the crossover from a low B regime which can be understood in terms of electrons following classical orbits to an inherently quantum high B regime where this classical picture and semiclassical theories based on it do not apply.Comment: 5 pages revtex + 2 postscript figure

    SYZ mirror symmetry for hypertoric varieties

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    We construct a Lagrangian torus fibration on a smooth hypertoric variety and a corresponding SYZ mirror variety using TT-duality and generating functions of open Gromov-Witten invariants. The variety is singular in general. We construct a resolution using the wall and chamber structure of the SYZ base.Comment: v_2: 31 pages, 5 figures, minor revision. To appear in Communications in Mathematical Physic

    Theory of conductance and noise additivity in parallel mesoscopic conductors

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    We present a theory of conductance and noise in generic mesoscopic conductors connected in parallel, and we demonstrate that the additivity of conductance and of shot noise arises as a sole property of the junctions connecting the two (or more) conductors in parallel. Consequences on the functionality of devices based on the Aharonov-Bohm effect are also drawn.Comment: 4 pages, 2 figure
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