4,466 research outputs found

    Seasonal Emergence Patterns of Black Flies (Diptera: Simuliidae) in Northwestern Pennsylvania

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    A two-year emergence trap study of black flies at four sites in northwestern Pennsylvania yielded 1%3 individuals of nine species. The collections included Prosimulium mixtum, P. jU5cum, Stegapterna mutata, Simulium aureum, S. excisum (recorded for the first time from Pennsylvania), S. gauldingi, S. sp. nr. innacens, S. vittatum, and S. tuberasum. Species richness for all sites peaked during May. Emergence collections below a sewage plant effluent outfall represented fewer individuals and species than collections above the effluent outfall. Chromosomal analysis of supplementary larval collections revealed the IIIL-l and IS-7 sibling species of S. vittatum and the FG sibling of S. tuberasum

    Zeroth Poisson homology of symmetric powers of isolated quasihomogeneous surface singularities

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    Let X be a surface with an isolated singularity at the origin, given by the equation Q(x,y,z)=0, where Q is a weighted-homogeneous polynomial. In particular, this includes the Kleinian surfaces X = C^2/G for G < SL(2,C) finite. Let Y be the n-th symmetric power of X. We compute the zeroth Poisson homology of Y, as a graded vector space with respect to the weight grading. In the Kleinian case, this confirms a conjecture of Alev, that the zeroth Poisson homology of the n-th symmetric power of C^2/G is isomorphic to the zeroth Hochschild homology of the n-th symmetric power of the algebra of G-invariant differential operators on C. That is, the Brylinski spectral sequence degenerates in this case. In the elliptic case, this yields the zeroth Hochschild homology of symmetric powers of the elliptic algebras with three generators modulo their center, for the parameter equal to all but countably many points of the elliptic curve.Comment: 17 page

    Spatial heterogeneity in projected leprosy trends in India

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    Background: Leprosy is caused by infection with Mycobacterium leprae and is characterized by peripheral nerve damage and skin lesions. The disease is classified into paucibacillary (PB) and multibacillary (MB) leprosy. The 2012 London Declaration formulated the following targets for leprosy control: (1) global interruption of transmission or elimination by 2020, and (2) reduction of grade-2 disabilities in newly detected cases to below 1 per million population at a global level by 2020. Leprosy is treatable, but diagnosis, access to treatment and treatment adherence (all necessary to curtail transmission) represent major challenges. Globally, new case detection rates for leprosy have remained fairly stable in the past decade, with India responsible for more than half of cases reported annually. Methods: We analyzed publicly available data from the Indian Ministry of Health and Family Welfare, and fit linear mixed-effects regression models to leprosy case detection trends reported at the district level. We assessed correlation of the new district-level case detection rate for leprosy with several state-level regressors: TB incidence, BCG coverage, fraction of cases exhibiting grade 2 disability at diagnosis, fraction of cases in children, and fraction multibacillary. Results: Our analyses suggest an endemic disease in very slow decline, with substantial spatial heterogeneity at both district and state levels. Enhanced active case finding was associated with a higher case detection rate. Conclusions: Trend analysis of reported new detection rates from India does not support a thesis of rapid progress in leprosy control

    Monitoring high-ozone events in the US Intermountain West using TEMPO geostationary satellite observations

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    High-ozone events, approaching or exceeding the National Ambient Air Quality Standard (NAAQS), are frequently observed in the US Intermountain West in association with subsiding air from the free troposphere. Monitoring and attribution of these events is problematic because of the sparsity of the current network of surface measurements and lack of vertical information. We present an Observing System Simulation Experiment (OSSE) to evaluate the ability of the future geostationary satellite instrument Tropospheric Emissions: Monitoring of Pollution (TEMPO), scheduled for launch in 2018–2019, to monitor and attribute high-ozone events in the Intermountain West through data assimilation. TEMPO will observe ozone in the ultraviolet (UV) and visible (Vis) bands to provide sensitivity in the lower troposphere. Our OSSE uses ozone data from the GFDL AM3 chemistry-climate model (CCM) as the "true" atmosphere and samples it for April–June 2010 with the current surface network (CASTNet –Clean Air Status and Trends Network– sites), a configuration designed to represent TEMPO, and a low Earth orbit (LEO) IR (infrared) satellite instrument. These synthetic data are then assimilated into the GEOS-Chem chemical transport model (CTM) using a Kalman filter. Error correlation length scales (500 km in horizontal, 1.7 km in vertical) extend the range of influence of observations. We show that assimilation of surface data alone does not adequately detect high-ozone events in the Intermountain West. Assimilation of TEMPO data greatly improves the monitoring capability, with little information added from the LEO instrument. The vertical information from TEMPO further enables the attribution of NAAQS exceedances to background ozone. This is illustrated with the case of a stratospheric intrusion

    The Very Low Albedo of WASP-12b From Spectral Eclipse Observations with Hubble\textit{Hubble}

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    We present an optical eclipse observation of the hot Jupiter WASP-12b using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. These spectra allow us to place an upper limit of Ag<0.064A_g < 0.064 (97.5% confidence level) on the planet's white light geometric albedo across 290--570 nm. Using six wavelength bins across the same wavelength range also produces stringent limits on the geometric albedo for all bins. However, our uncertainties in eclipse depth are ∼\sim40% greater than the Poisson limit and may be limited by the intrinsic variability of the Sun-like host star --- the solar luminosity is known to vary at the 10−410^{-4} level on a timescale of minutes. We use our eclipse depth limits to test two previously suggested atmospheric models for this planet: Mie scattering from an aluminum-oxide haze or cloud-free Rayleigh scattering. Our stringent nondetection rules out both models and is consistent with thermal emission plus weak Rayleigh scattering from atomic hydrogen and helium. Our results are in stark contrast with those for the much cooler HD 189733b, the only other hot Jupiter with spectrally resolved reflected light observations; those data showed an increase in albedo with decreasing wavelength. The fact that the first two exoplanets with optical albedo spectra exhibit significant differences demonstrates the importance of spectrally resolved reflected light observations and highlights the great diversity among hot Jupiters.Comment: 8 pages, 4 figures, 1 table, published in ApJL, in pres

    Capillary filling with wall corrugations] Capillary filling in microchannels with wall corrugations: A comparative study of the Concus-Finn criterion by continuum, kinetic and atomistic approaches

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    We study the impact of wall corrugations in microchannels on the process of capillary filling by means of three broadly used methods - Computational Fluid Dynamics (CFD), Lattice-Boltzmann Equations (LBE) and Molecular Dynamics (MD). The numerical results of these approaches are compared and tested against the Concus-Finn (CF) criterion, which predicts pinning of the contact line at rectangular ridges perpendicular to flow for contact angles theta > 45. While for theta = 30, theta = 40 (no flow) and theta = 60 (flow) all methods are found to produce data consistent with the CF criterion, at theta = 50 the numerical experiments provide different results. Whilst pinning of the liquid front is observed both in the LB and CFD simulations, MD simulations show that molecular fluctuations allow front propagation even above the critical value predicted by the deterministic CF criterion, thereby introducing a sensitivity to the obstacle heigth.Comment: 25 pages, 8 figures, Langmuir in pres

    Exploring the reactivity of 2-trichloromethylbenzoxazoles for access to substituted benzoxazoles

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    The reactivity of 2-trichloromethylbenzoxazoles towards various nucleophiles, under metal free or iron-catalyzed conditions, for the synthesis of substituted benzoxazoles is described. These methods allow for selective substitution at either the 2- or 2’- position of the benzoxazoles using the same starting materials / reagents. This approach allows for the controlled synthesis of a variety of key derivatives from a single 2-trichloromethylbenzoxazole starting material

    Muscular Performance and Neuromuscular Fatigue are not Sex-Dependent During Low-Load Fatiguing Bilateral Leg Extension Exercise

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    Purpose. This study examined the sex-related differences in muscular performance and neuromuscular (electromyographic [EMG] and mechanomyographic [MMG] amplitude [AMP] and mean power frequency [MPF]) responses during fatiguing leg extension repetitions performed at the critical load (CL). Methods. Eleven men and nine women completed one-repetition maximum (1RM) testing, repetitions to failure at 50, 60, 70, and 80% 1RM to determine CL, and repetitions to failure at CL, on separate days. The EMG and MMG, AMP and MPF signals and number of repetitions completed were recorded. Results. There were no sex-dependent responses in the %1RM that corresponded to, the number of repetitions completed at, or the neuromuscular responses during repetitions performed to failure at CL. There were time-dependent responses in EMG AMP from 25-100% of total repetitions completed, respectively. The EMG MPF and MMG MPF demonstrated fatigue-induced decreases from 50-100% and at 100% of total repetitions completed, respectively. There was no change over time for MMG AMP. Conclusions. These findings indicated men and women responded similarly to leg extension exercise performed at the CL. Further, sex-dependent responses to fatiguing exercise may be related to the amount of active muscle mass engaged in exercise and the corresponding afferent feedback that influences peripheral fatigue and central drive during fatiguing tasks

    Boundary conditions at a fluid - solid interface

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    We study the boundary conditions at a fluid-solid interface using molecular dynamics simulations covering a broad range of fluid-solid interactions and fluid densities, and both simple and chain-molecule fluids. The slip length is shown to be independent of the type of flow, but rather is related to the fluid organization near the solid, as governed by the fluid-solid molecular interactions.Comment: REVtex, to appear in Physical Review Letter
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