5,426 research outputs found

    Estimation of glottal closure instants in voiced speech using the DYPSA algorithm

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    Capacity strengthening in malaria research: the Gates Malaria Partnership.

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    The Gates Malaria Partnership (GMP) includes five African and four European partner institutions. Its research programme has five priority areas involving an extensive range of field-based studies. GMP research has contributed significantly to the development of new research consortia investigating strategies for improving means of malaria control, and has already had an impact on policy and practice. A substantial investment in innovative training activities in malaria has enhanced knowledge and practice of malaria control at all levels from policy making to local community involvement. Capacity development, notably through a PhD programme, has been an underlying feature of all aspects of the programme

    IUE observations of the 1987 superoutburst of the dwarf nova Z Cha

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    Low resolution IUE observations of the dwarf nova Z Cha during superoutburst are presented. These cover most of the development of the outburst and have sufficient time resolution to probe continuum and line behavior on orbital phase. The observed modulation on this phase is very similar to that observed in the related object OY Car. The results imply the presence of a cool spot on the edge of the edge of the accretion disk, which periodically occults the brighter inner disk. Details of the line behavior suggest that the line originated in an extended wind-emitting region. In contrast to archive spectra obtained in normal outburst, the continuum is fainter and redder, indicating that the entire superoutburst disk may be geometrically thicker than during a normal outburst

    Quasi-normal modes for doubly rotating black holes

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    Based on the work of Chen, L\"u and Pope, we derive expressions for the D6D\geq 6 dimensional metric for Kerr-(A)dS black holes with two independent rotation parameters and all others set equal to zero: a10,a20,a3=a4=...=0a_1\neq 0, a_2\neq0, a_3=a_4=...=0. The Klein-Gordon equation is then explicitly separated on this background. For D6D\geq 6 this separation results in a radial equation coupled to two generalized spheroidal angular equations. We then develop a full numerical approach that utilizes the Asymptotic Iteration Method (AIM) to find radial Quasi-Normal Modes (QNMs) of doubly rotating flat Myers-Perry black holes for slow rotations. We also develop perturbative expansions for the angular quantum numbers in powers of the rotation parameters up to second order.Comment: RevTeX 4-1, various figure

    The Submillimeter Array

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    The Submillimeter Array (SMA), a collaborative project of the Smithsonian Astrophysical Observatory (SAO) and the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), has begun operation on Mauna Kea in Hawaii. A total of eight 6-m telescopes comprise the array, which will cover the frequency range of 180-900 GHz. All eight telescopes have been deployed and are operational. First scientific results utilizing the three receiver bands at 230, 345, and 690 GHz have been obtained and are presented in the accompanying papers.Comment: 10 pages, 4 figure

    Two similar commercial live attenuated AMPV vaccines prepared by random passage of the identical field isolate, have unrelated sequences

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    Since late \u201880 s Avian metapneumovirus subtype A causes sufficient disease in Europe for commercial companies to have started developing live attenuated vaccines. Here, two of those vaccines were fully consensus sequenced alongside their progenitor field strain (#8544). Sequences comparison shows that the attenuation of field strain #8544 was associated with no common substitutions between the two derived vaccines. This finding suggests that the attenuation of field viruses via serial passage on cell cultures or tissues is the result of a random process, rather than a mechanism aiming to achieve a specific sequence. Furthermore, field vaccination strategies would greatly benefit by the unambiguous vaccine markers identified in this study, enabling a prompt and confident vaccines detection

    Zeta Functions in Brane World Cosmology

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    We present a calculation of the zeta function and of the functional determinant for a Laplace-type differential operator, corresponding to a scalar field in a higher dimensional de Sitter brane background, which consists of a higher dimensional anti-de Sitter bulk spacetime bounded by a de Sitter section, representing a brane. Contrary to the existing examples, which all make use of conformal transformations, we evaluate the zeta function working directly with the higher dimensional wave operator. We also consider a generic mass term and coupling to curvature, generalizing previous results. The massless, conformally coupled case is obtained as a limit of the general result and compared with known calculations. In the limit of large anti-de Sitter radius, the zeta determinant for the ball is recovered in perfect agreement with known expressions, providing an interesting check of our result and an alternative way of obtaining the ball determinant.Comment: 14 pages, 1 figur

    The Origin of Soft X-rays in DQ Herculis

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    DQ Herculis (Nova Herculis 1934) is a deeply eclipsing cataclysmic variable containing a magnetic white dwarf primary. The accretion disk is thought to block our line of sight to the white dwarf at all orbital phases due to its extreme inclination angle. Nevertheless, soft X-rays were detected from DQ Her with ROSAT PSPC. To probe the origin of these soft X-rays, we have performed Chandra ACIS observations. We confirm that DQ Her is an X-ray source. The bulk of the X-rays are from a point-like source and exhibit a shallow partial eclipse. We interpret this as due to scattering of the unseen central X-ray source, probably in an accretion disk wind. At the same time, we observe what appear to be weak extended X-ray features around DQ Her, which we interpret as an X-ray emitting knot in the nova shell.Comment: 18 pages including 4 figures, accepted for publication in Astrphyisical Journa
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