270 research outputs found

    Influence of airfoil geometry on delta wing leading-edge vortices and vortex-induced aerodynamics at supersonic speeds

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    An assessment of the influence of airfoil geometry on delta wing leading edge vortex flow and vortex induced aerodynamics at supersonic speeds is discussed. A series of delta wing wind tunnel models were tested over a Mach number range from 1.7 to 2.0. The model geometric variables included leading edge sweep and airfoil shape. Surface pressure data, vapor screen, and oil flow photograph data were taken to evaluate the complex structure of the vortices and shocks on the family of wings tested. The data show that airfoil shape has a significant impact on the wing upper surface flow structure and pressure distribution, but has a minimal impact on the integrated upper surface pressure increments

    How to Read a Visualization Research Paper: Extracting the Essentials

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    Introduction. Women's sexual pain disorders include dyspareunia and vaginismus and there is need for state-of-the-art information in this area. Aim. To update the scientific evidence published in 2004, from the 2nd International Consultation on Sexual Medicine pertaining to the diagnosis and treatment of women's sexual pain disorders. Methods. An expert committee, invited from six countries by the 3rd International Consultation, was comprised of eight researchers and clinicians from biological and social science disciplines, for the purpose of reviewing and grading the scientific evidence on nosology, etiology, diagnosis, and treatment of women's sexual pain disorders. Main Outcome Measure. Expert opinion was based on grading of evidence-based medical literature, extensive internal committee discussion, public presentation, and debate. Results. A comprehensive assessment of medical, sexual, and psychosocial history is recommended for diagnosis and management. Indications for general and focused pelvic genital examination are identified. Evidence-based recommendations for assessment of women's sexual pain disorders are reviewed. An evidence-based approach to management of these disorders is provided. Conclusions. Continued efforts are warranted to conduct research and scientific reporting on the optimal assessment and management of women's sexual pain disorders, including multidisciplinary approaches. van Lankveld JJDM, Granot M, Weijmar Schultz WCM, Binik YM, Wesselmann U, Pukall CF, Bohm-Starke N, and Achtrari C. Women's sexual pain disorders. J Sex Med 2010;7:615-631

    Genetic and oceanographic tools reveal high population connectivity and diversity in the endangered pen shell Pinna nobilis

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    For marine meta-populations with source-sink dynamics knowledge about genetic connectivity is important to conserve biodiversity and design marine protected areas (MPAs). We evaluate connectivity of a Mediterranean sessile species, Pinna nobilis. To address a large geographical scale, partial sequences of cytochrome oxidase I (COI, 590 bp) were used to evaluate phylogeographical patterns in the Western Mediterranean, and in the whole basin using overlapping sequences from the literature (243 bp). Additionally, we combined (1) larval trajectories based on oceanographic currents and early life-history traits and (2) 10 highly polymorphic microsatellite loci collected in the Western Mediterranean. COI results provided evidence for high diversity and low inter-population differentiation. Microsatellite genotypes showed increasing genetic differentiation with oceanographic transport time (isolation by oceanographic distance (IBD) set by marine currents). Genetic differentiation was detected between Banyuls and Murcia and between Murcia and Mallorca. However, no genetic break was detected between the Balearic populations and the mainland. Migration rates together with numerical Lagrangian simulations showed that (i) the Ebro Delta is a larval source for the Balearic populations (ii) Alicante is a sink population, accumulating allelic diversity from nearby populations. The inferred connectivity can be applied in the development of MPA networks in the Western MediterraneanProject MEDEICG funded by the Spanish Ministry of Economy and Competitiveness (CTM2009-07013)IEH was supported by Ramon y Cajal Fellowship RYC2014-14970Spanish Ministry of Economy, Industry and Competitiveness IFCT Investigator Programme-Career Development (IF/00998/2014)MGW and AHE was supported by FCT fellowships SFRH/BPD/63703/2009 and SFRH/BPD/107878/2015National Science Foundation (OCE-1419450)CCMAR team via excellence research line EXCL/AAG-GLO/0661/2012Ciencias del Ma

    Nuclear transparency and effective kaon-nucleon cross section from the A(e, e'K+) reaction

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    We have determined the transparency of the nuclear medium to kaons from A(e,eK+)A(e,e^{'} K^{+}) measurements on 12^{12}C, 63^{63}Cu, and 197^{197}Au targets. The measurements were performed at the Jefferson Laboratory and span a range in four-momentum-transfer squared Q2^2=1.1 -- 3.0 GeV2^2. The nuclear transparency was defined as the ratio of measured kaon electroproduction cross sections with respect to deuterium, (σA/σD\sigma^{A}/\sigma^{D}). We further extracted the atomic number (AA) dependence of the transparency as parametrized by T=(A/2)α1T= (A/2)^{\alpha-1} and, within a simple model assumption, the in-medium effective kaon-nucleon cross sections. The effective cross sections extracted from the electroproduction data are found to be smaller than the free cross sections determined from kaon-nucleon scattering experiments, and the parameter α\alpha was found to be significantly larger than those obtained from kaon-nucleus scattering. We have included similar comparisons between pion- and proton-nucleon effective cross sections as determined from electron scattering experiments, and pion-nucleus and proton-nucleus scattering data.Comment: 7 pages, 5 figure

    Measurement of Nuclear Transparency for the A(e,e' pi^+) Reaction

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    We have measured the nuclear transparency of the A(e,e' pi^+) process in ^{2}H,^{12}C, ^{27}Al, ^{63}Cu and ^{197}Au targets. These measurements were performed at the Jefferson Laboratory over a four momentum transfer squared range Q^2 = 1.1 - 4.7 (GeV/c)^2. The nuclear transparency was extracted as the super-ratio of (σA/σH)(\sigma_A/\sigma_H) from data to a model of pion-electroproduction from nuclei without pi-N final state interactions. The Q^2 and atomic number dependence of the nuclear transparency both show deviations from traditional nuclear physics expectations, and are consistent with calculations that include the quantum chromodynamical phenomenon of color transparency.Comment: 5 pages, 3 figs Changes to figure 2 and 3 (error band updated and theory curves updated

    Scaling study of the pion electroproduction cross sections and the pion form factor

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    The 1^{1}H(e,eπ+e,e^\prime \pi^+)n cross section was measured for a range of four-momentum transfer up to Q2Q^2=3.91 GeV2^2 at values of the invariant mass, WW, above the resonance region. The Q2Q^2-dependence of the longitudinal component is consistent with the Q2Q^2-scaling prediction for hard exclusive processes. This suggests that perturbative QCD concepts are applicable at rather low values of Q2Q^2. Pion form factor results, while consistent with the Q2Q^2-scaling prediction, are inconsistent in magnitude with perturbative QCD calculations. The extraction of Generalized Parton Distributions from hard exclusive processes assumes the dominance of the longitudinal term. However, transverse contributions to the cross section are still significant at Q2Q^2=3.91 GeV2^2.Comment: 6 pages, 3 figure

    Study of the A(e,e'π+\pi^+) Reaction on 1^1H, 2^2H, 12^{12}C, 27^{27}Al, 63^{63}Cu and 197^{197}Au

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    Cross sections for the p(e,eπ+e,e'\pi^{+})n process on 1^1H, 2^2H, 12^{12}C, 27^{27}Al, 63^{63}Cu and 197^{197}Au targets were measured at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) in order to extract the nuclear transparencies. Data were taken for four-momentum transfers ranging from Q2Q^2=1.1 to 4.8 GeV2^2 for a fixed center of mass energy of WW=2.14 GeV. The ratio of σL\sigma_L and σT\sigma_T was extracted from the measured cross sections for 1^1H, 2^2H, 12^{12}C and 63^{63}Cu targets at Q2Q^2 = 2.15 and 4.0 GeV2^2 allowing for additional studies of the reaction mechanism. The experimental setup and the analysis of the data are described in detail including systematic studies needed to obtain the results. The results for the nuclear transparency and the differential cross sections as a function of the pion momentum at the different values of Q2Q^2 are presented. Global features of the data are discussed and the data are compared with the results of model calculations for the p(e,eπ+e,e'\pi^{+})n reaction from nuclear targets.Comment: 28 pages, 19 figures, submited to PR
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