2,945 research outputs found

    The Benjamin H. Kean Travel Fellowship in Tropical Medicine: Assessment of Impact at 15 Years

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    Abstract. The Benjamin H. Kean Fellowship in Tropical Medicine is an American Society of Tropical Medicine and Hygiene initiative that provides medical students with funding for international clinical or research experiences lasting at least 1 month. Of the 175 Kean fellows from 1998 to 2013, 140 had current available e-mails, and 70 of the 140 (50%) responded to a survey about their fellowship experience. Alumni indicated that the Kean Fellowship had a high impact on their career plans with regard to preparation for (N = 65, 94.2%) and inspiration to pursue (N = 59, 88.1%) a career in tropical medicine and global health. Continued involvement in tropical medicine and global health was common: 52 alumni (74.3%) were currently working in tropical medicine or global health, 49 (71.0%) had done so in the interim between the Kean fellowship and their current position; and 17 of 19 Kean fellows (89.4%) who had completed all medical training and were now in professional practice continued to work in tropical medicine and global health. Alumni had been highly productive academically, publishing a total of 831 PubMed-indexed manuscripts, almost all on tropical medicine or global health topics, in the period between their fellowship year and 2013. Alumni reported strengths of the fellowship including funding, networking, and flexibility, and suggested that more networking and career mentoring would enhance the program. The Benjamin H. Kean fellowship program has been highly successful at inspiring and fostering ongoing work by trainees in tropical medicine and global health

    Experimental Status of Exotic Mesons and the GlueX Experiment

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    One of the unanswered and most fundamental questions in physics regards the nature of the confinement mechanism of quarks and gluons in QCD. Exotic hybrid mesons manifest gluonic degrees of freedom and their spectroscopy will provide the data necessary to test assumptions in lattice QCD and the specific phenomenology leading to confinement. Within the past two decades a number of experiments have put forth tantalizing evidence for the existence of exotic hybrid mesons in the mass range below 2 GeV. This talk represents an overview of the available data and what has been learned. In looking toward the future, the GlueX experiment at Jefferson Laboratory represents a new initiative that will perform detailed spectroscopy of the light-quark meson spectrum. This experiment and its capabilities will be reviewed.Comment: 10 pages, 8 figures, 2nd Meeting of the APS Topical Group on Hadron Physics GHP06, Nashville, TN (10/22-10/24/06

    Theory of Pump Depletion and Spike Formation in Stimulated Raman Scattering

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    By using the inverse spectral transform, the SRS equations are solved and the explicit output data is given for arbitrary laser pump and Stokes seed profiles injected on a vacuum of optical phonons. For long duration laser pulses, this solution is modified such as to take into account the damping rate of the optical phonon wave. This model is used to interprete the experiments of Druhl, Wenzel and Carlsten (Phys. Rev. Lett., (1983) vol. 51, p. 1171), in particular the creation of a spike of (anomalous) pump radiation. The related nonlinear Fourier spectrum does not contain discrete eigenvalue, hence this Raman spike is not a soliton.Comment: LaTex file, includes two figures in LaTex format, 9 page

    Age-specific vaccine effectiveness of seasonal 2010/2011 and pandemic influenza A(H1N1) 2009 vaccines in preventing influenza in the United Kingdom

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    An analysis was undertaken to measure age-specific vaccine effectiveness (VE) of 2010/11 trivalent seasonal influenza vaccine (TIV) and monovalent 2009 pandemic influenza vaccine (PIV) administered in 2009/2010. The test-negative case-control study design was employed based on patients consulting primary care. Overall TIV effectiveness, adjusted for age and month, against confirmed influenza A(H1N1)pdm 2009 infection was 56% (95% CI 42–66); age-specific adjusted VE was 87% (95% CI 45–97) in <5-year-olds and 84% (95% CI 27–97) in 5- to 14-year-olds. Adjusted VE for PIV was only 28% (95% CI x6 to 51) overall and 72% (95% CI 15–91) in <5-year-olds. For confirmed influenza B infection, TIV effectiveness was 57% (95% CI 42–68) and in 5- to 14-year-olds 75% (95% CI 32–91). TIV provided moderate protection against the main circulating strains in 2010/2011, with higher protection in children. PIV administered during the previous season provided residual protection after 1 year, particularly in the <5 years age group

    The Effect of Air on Granular Size Separation in a Vibrated Granular Bed

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    Using high-speed video and magnetic resonance imaging (MRI) we study the motion of a large sphere in a vertically vibrated bed of smaller grains. As previously reported we find a non-monotonic density dependence of the rise and sink time of the large sphere. We find that this density dependence is solely due to air drag. We investigate in detail how the motion of the intruder sphere is influenced by size of the background particles, initial vertical position in the bed, ambient pressure and convection. We explain our results in the framework of a simple model and find quantitative agreement in key aspects with numerical simulations to the model equations.Comment: 14 pages, 16 figures, submitted to PRE, corrected typos, slight change

    Coherent control using adaptive learning algorithms

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    We have constructed an automated learning apparatus to control quantum systems. By directing intense shaped ultrafast laser pulses into a variety of samples and using a measurement of the system as a feedback signal, we are able to reshape the laser pulses to direct the system into a desired state. The feedback signal is the input to an adaptive learning algorithm. This algorithm programs a computer-controlled, acousto-optic modulator pulse shaper. The learning algorithm generates new shaped laser pulses based on the success of previous pulses in achieving a predetermined goal.Comment: 19 pages (including 14 figures), REVTeX 3.1, updated conten

    6^6Li-loaded liquid scintillators produced by direct dissolution of compounds in diisopropylnaphthalene (DIPN)

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    The paper describes preparation of 6^6Li-loaded liquid scintillators by methods involving direct dissolution of 6^6Li salts in the commercial diisopropylnaphthalene (DIPN) solvent, without the formation of water-in-oil emulsions. Methods include incorporation of 6^6Li that, unlike previously reported formulations, does not require additions of water or a strong acid such as hydrochloric acid (HCl). Results of the conducted experiments show that dissolution of aromatic and aliphatic 6^6Li salts in DIPN can be easily achieved at 0.1- 0.3% by weight of atomic 6^6Li, using small additions of waterless surfactants, or mild carboxylic acids. An alternative way suggests incorporation of 6^6Li as a part of a surfactant molecule that can be dissolved in DIPN without any solubilizing additions. Proposed methods enable preparation of efficient 6^6Li-loaded liquid scintillators that, at a large scale of 50 cm, exhibit good pulse shape discrimination (PSD) properties combined with up to 107% of light output and up to 115% of the attenuation length measured relative to standard undoped EJ-309 liquid scintillator.Comment: Submitted to Nuclear Instruments and Methods in Physics Research
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