272 research outputs found

    Fundamental and clinical evaluation of "SCC RIABEAD" kit for immuno radiometric assay of squamous cell carcinoma related antigen.

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    Classic vector control strategies target mosquitoes indoors as the main transmitters of malaria are indoor-biting and –resting mosquitoes. However, the intensive use of insecticide-treated bed-nets (ITNs) and indoor residual spraying have put selective pressure on mosquitoes to adapt in order to obtain human blood meals. Thus, early-evening and outdoor vector activity is becoming an increasing concern. This study assessed the effect of a deltamethrin-treated net (100 mg/m2) attached to a one-meter high fence around outdoor cattle enclosures on the number of mosquitoes landing on humans. Mosquitoes were collected from four cattle enclosures: Pen A – with cattle and no net; B – with cattle and protected by an untreated net; C – with cattle and protected by a deltamethrin-treated net; D – no cattle and no net. A total of 3217 culicines and 1017 anophelines were collected, of which 388 were Anopheles gambiae and 629 An. ziemanni. In the absence of cattle nearly 3 times more An. gambiae (p<0.0001) landed on humans. The deltamethrin-treated net significantly reduced (nearly three-fold, p<0.0001) culicine landings inside enclosures. The sporozoite rate of the zoophilic An. ziemanni, known to be a secondary malaria vector, was as high as that of the most competent vector An. gambiae; raising the potential of zoophilic species as secondary malaria vectors. After deployment of the ITNs a deltamethrin persistence of 9 months was observed despite exposure to African weather conditions. The outdoor use of ITNs resulted in a significant reduction of host-seeking culicines inside enclosures. Further studies investigating the effectiveness and spatial repellence of ITNs around other outdoor sites, such as bars and cooking areas, as well as their direct effect on vector-borne disease transmission are needed to evaluate its potential as an appropriate outdoor vector control tool for rural Africa

    Vortex core transitions in superfluid 3He in globally anisotropic aerogels

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    Core structures of a single vortex in A-like and B-like phases of superfluid 3He in uniaxially compressed and stretched aerogels are studied by numerically solving Ginzburg-Landau equations derived microscopically. It is found that, although any uniaxial deformation leads to a wider A-like phase with the axial pairing in the pressure-temperature phase diagram, the vortex core states in the two phases in aerogel depend highly on the type of deformation. In a compressed aerogel, the first-order vortex core transition (VCT) previously seen in the bulk B phase appears at any pressure in the B-like phase while no strange vortex core is expected in the corresponding A-like phase. By contrast, in a stretched aerogel, the VCT in the B-like phase is lost while another VCT is expected to occur between a nonunitary core and a polar one in the A-like phase. Experimental search for these results is hoped to understand correlation between superfluid 3He and aerogel structure.Comment: 7 pages, 6 figures Text was changed. Resubmitted versio

    Soliton-like Spin State in the A-like Phase of 3He in Anisotropic Aerogel

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    We have found a new stable spin state in the A-like phase of superfluid 3He confined to intrinsically anisotropic aerogel. The state can be formed by radiofrequency excitation applied while cooling through the superfluid transition temperature and its NMR properties are different from the standard A-like phase obtained in the limit of very small excitation. It is possible that this new state is formed by textural domain walls pinned by aerogel.Comment: 9 pages, 3 figures. Submitted to J. of Low Tem. Phys. (QFS2007 Proceedings

    NMR in Superfluid A-like Phase of 3^3He Confined in Globally Deformed Aerogel in Tilted Magnetic Field

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    NMR spectra in superfluid A-like phases confined in axially deformed aerogel in presence of a magnetic field inclined with respect to deformation axis is considered. The characteristic features of dipole frequency shift in axially compressed and axially stretched cases are compared. In particular, it is shown that in axially stretched aerogel environment the stability region of coherently spin precessing mode is rather narrow due to the U(1)LIM effect.Comment: 8 pages, 2 figure

    Phase diagram of superfluid 3He in "nematically ordered" aerogel

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    Results of experiments with liquid 3He immersed in a new type of aerogel are described. This aerogel consists of Al2O3 strands which are nearly parallel to each other, so we call it as a "nematically ordered" aerogel. At all used pressures a superfluid transition was observed and a superfluid phase diagram was measured. Possible structures of the observed superfluid phases are discussed.Comment: 6 pages, 8 figures. Submitted to Pis'ma v ZhETF (JETP Letters

    Assessing the Forms and Functions of Aggression Using Self-Report: Factor Structure and Invariance of the Peer Conflict Scale in Youths

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    This study examined the structure of a self-report measure of the forms and functions of aggression in 855 adolescents (582 boys, 266 girls) aged 12 to 19 years recruited from high school, detained, and residential settings. The Peer Conflict Scale (PCS) is a 40-item measure that was developed to improve upon existing measures and provide an efficient, reliable, and valid assessment of four dimensions of aggression (i.e., reactive overt, reactive relational, proactive overt, and proactive relational) in youths. Confirmatory factor analyses showed that a 4-factor model represented a satisfactory solution for the data. The factor structure fit well for both boys and girls and across high school, detained, and residential samples. Internal consistency estimates were good for the 4 factors, and they showed expected associations with externalizing variables (i.e., arrest history, callous-unemotional traits, and delinquency). Reactive and proactive subtypes showed unique associations consistent with previous literature. Implications for the use of the PCS to assess aggression and inform intervention decisions in diverse samples of youths are discussed

    Orbital glass and spin glass states of 3He-A in aerogel

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    Glass states of superfluid A-like phase of 3He in aerogel induced by random orientations of aerogel strands are investigated theoretically and experimentally. In anisotropic aerogel with stretching deformation two glass phases are observed. Both phases represent the anisotropic glass of the orbital ferromagnetic vector l -- the orbital glass (OG). The phases differ by the spin structure: the spin nematic vector d can be either in the ordered spin nematic (SN) state or in the disordered spin-glass (SG) state. The first phase (OG-SN) is formed under conventional cooling from normal 3He. The second phase (OG-SG) is metastable, being obtained by cooling through the superfluid transition temperature, when large enough resonant continuous radio-frequency excitation are applied. NMR signature of different phases allows us to measure the parameter of the global anisotropy of the orbital glass induced by deformation.Comment: 7 pages, 6 figures, Submitted to Pis'ma v ZhETF (JETP Letters

    Pseudo-single crystal electrochemistry on polycrystalline electrodes : visualizing activity at grains and grain boundaries on platinum for the Fe2+/Fe3+ redox reaction

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    The influence of electrode surface structure on electrochemical reaction rates and mechanisms is a major theme in electrochemical research, especially as electrodes with inherent structural heterogeneities are used ubiquitously. Yet, probing local electrochemistry and surface structure at complex surfaces is challenging. In this paper, high spatial resolution scanning electrochemical cell microscopy (SECCM) complemented with electron backscatter diffraction (EBSD) is demonstrated as a means of performing ‘pseudo-single-crystal’ electrochemical measurements at individual grains of a polycrystalline platinum electrode, while also allowing grain boundaries to be probed. Using the Fe2+/3+ couple as an illustrative case, a strong correlation is found between local surface structure and electrochemical activity. Variations in electrochemical activity for individual high index grains, visualized in a weakly adsorbing perchlorate medium, show that there is higher activity on grains with a significant (101) orientation contribution, compared to those with (001) and (111) contribution, consistent with findings on single-crystal electrodes. Interestingly, for Fe2+ oxidation in a sulfate medium a different pattern of activity emerges. Here, SECCM reveals only minor variations in activity between individual grains, again consistent with single-crystal studies, with a greatly enhanced activity at grain boundaries. This suggests that these sites may contribute significantly to the overall electrochemical behavior measured on the macroscale

    Distillation of hydrogen isotopes for polarized HD target

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    We have developed a cryogenic distillation system to purify Hydrogen-Deuteride (HD) gas for a polarized HD target in LEPS experiments at SPring-8. A small amount of ortho-H2_2 (\sim0.01%) in the HD gas plays an important role in efficiently polarizing the HD target. Since there are 1\sim5% impurities of H2_2 and D2_2 in commercially available HD gases, it is inevitable that the HD gas is purified up to \sim99.99%. The distillation system has a cryogenic pot (17\sim21 K) containing many small stainless steel cells called Heli-pack. Commercial HD gas with an amount of 5.2 mol is fed into the pot. We carried out three distillation runs by changing temperatures (17.5 K and 20.5 K) and gas extraction speeds (1.3 ml/min and 5.2 ml/min). The extracted gas was analyzed by using a gas analyzer system combining a quadrupole mass spectrometer with a gas chromatograph. The HD gas of 1 mol with a purity better than 99.99% has been successfully obtained. The effective NTS (Number of Theoretical Stages), which is an indicator of the distillator performances, is obtained as 37.2±\pm0.6. This value is in reasonable agreement with a designed value of 37.9. The HD target is expected to be efficiently polarized under a well-controlled condition by doping an optimal amount of ortho-H2_2 to the purified HD gas.Comment: 7 pages, 8 figures, 2 tables, updated 2011-12-1

    Energy spectra of fractional quantum Hall systems in the presence of a valence hole

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    The energy spectrum of a two-dimensional electron gas (2DEG) in the fractional quantum Hall regime interacting with an optically injected valence band hole is studied as a function of the filling factor ν\nu and the separation dd between the electron and hole layers. The response of the 2DEG to the hole changes abruptly at dd of the order of the magnetic length λ\lambda. At d<λd<\lambda, the hole binds electrons to form neutral (XX) or charged (XX^-) excitons, and the photoluminescence (PL) spectrum probes the lifetimes and binding energies of these states rather than the original correlations of the 2DEG. The ``dressed exciton'' picture (in which the interaction between an exciton and the 2DEG was proposed to merely enhance the exciton mass) is questioned. Instead, the low energy states are explained in terms of Laughlin correlations between the constituent fermions (electrons and XX^-'s) and the formation of two-component incompressible fluid states in the electron--hole plasma. At d>2λd>2\lambda, the hole binds up to two Laughlin quasielectrons (QE) of the 2DEG to form fractionally charged excitons hhQEn_n. The previously found ``anyon exciton'' hhQE3_3 is shown to be unstable at any value of dd. The critical dependence of the stability of different hhQEn_n complexes on the presence of QE's in the 2DEG leads to the observed discontinuity of the PL spectrum at ν=13\nu={1\over3} or 23{2\over3}.Comment: 16 pages, 14 figures, submitted to PR
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