2,072 research outputs found

    Ab initio study of electron-phonon interaction in phosphorene

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    The monolayer of black phosphorous, or phosphorene, has recently emerged as a new 2D semiconductor with intriguing highly anisotropic transport properties. Existing calculations of its intrinsic phonon-limited electronic transport properties so far rely on the deformation potential approximation, which is in general not directly applicable to anisotropic materials since the deformation along one specific direction can scatter electrons traveling in all directions. We perform a first-principles calculation of the electron-phonon interaction in phosphorene based on density functional perturbation theory and Wannier interpolation. Our calculation reveals that 1) the high anisotropy provides extra phase space for electron-phonon scattering, and 2) optical phonons have appreciable contributions. Both effects cannot be captured by the deformation potential calculations.Comment: 25 pages, 15 figure

    Viral Determinants of FeLV Infection and Pathogenesis: Lessons Learned from Analysis of a Natural Cohort

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    Detailed analysis has been performed over many years of a geographic and temporal cohort of cats naturally infected with feline leukemia virus (FeLV). Molecular analysis of FeLV present in the diseased tissues and application of those viruses to experimental systems has revealed unique isolates with distinctive disease potential, previously uncharacterized virus-receptor interactions, information about the role of recombinant viruses in disease induction, and novel viral and cellular oncogenes implicated in pathogenesis, among other findings. The studies have contributed to an understanding of the selective forces that lead to predominance of distinctive FeLV isolates and disease outcomes in a natural population

    Abridged bibliography of photographic interpretation : selected with emphasis upon keys, techniques, and research

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    This bibliography, PIC Report No. 102A/50, is a literature review of the applications of aerial photography. It is a classified list covering applications for archaeology, engineering, forestry, geography, geology, soil science, and the study of vegetation. The copy used to create this digital document was borrowed from the Maury Oceanographic Library, Stennis Space Center, MS

    Keck and Gemini spectral characterization of Lucy mission fly-by target (152830) Dinkinesh

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    Recently, the inner main belt asteroid (152830) Dinkinesh was identified as an additional fly-by target for the Lucy mission. The heliocentric orbit and approximate absolute magnitude of Dinkinesh are known, but little additional information was available prior to its selection as a target. In particular, the lack of color spectrophotometry or spectra made it impossible to assign a spectral type to Dinkinesh from which its albedo could be estimated. We set out to remedy this knowledge gap by obtaining visible wavelength spectra with the Keck telescope on 2022 November 23 and with Gemini-South on 2022 December 27. The spectra measured with the Keck I/Low Resolution Imaging Spectrometer (LRIS) and the Gemini South/Gemini Multi-Object Spectrograph South (GMOS-S) are most similar to the average spectrum of S- and Sq-type asteroids. The most diagnostic feature is the \approx15±\pm1%\% silicate absorption feature at \approx0.9-1.0~micron. Small S- and Sq-type asteroids have moderately high albedos ranging from 0.17-0.35. Using this albedo range for Dinkinesh in combination with measured absolute magnitude, it is possible to derive an effective diameter and surface brightness for this body. The albedo, size and surface brightness are important inputs required for planning a successful encounter by the Lucy spacecraft.Comment: 7 pages, 1 figure. Under review in Icaru

    Experimental Reproduction of Severe Disease in CD/CD Pigs Coinfected with PRRSV and Type 2 Porcine Circovirus

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    Postweaning multisystemic wasting syndrome (PMWS) has been recognized worldwide and is characterized clinically by wasting, dyspnea, and occasionally by icterus in nursery and grow-finish pigs. Type 2 porcine circovirus (PCV2) is consistently demonstrated in PMWS lesions. At the Iowa State University Veterinary Diagnostic Laboratory, both porcine reproductive and respiratory syndrome virus (PRRSV) and PCV2 are detected in tissues from most cases of PMWS. Since PRRSV-PCV2 coinfection has also been associated with “atypical PRRS” hepatitis, 3 week old cesarean-derived, colostrum-deprived (CD/CD) pigs were inoculated with PRRSV, PCV2, both PRRSV and PCV2, or uninfected cell culture media in order to compare the independent and combined effects of these agents. PRRSV-inoculated pigs developed respiratory distress and interstitial pneumonia typical of that previously reported for this agent. None of the pigs in the PRRSV or control groups became moribund or developed hepatitis. PCV2-inoculated pigs developed lymphoid depletion and sporadic hepatitis associated with 40% mortality. Pigs in the PRRSV/PCV2 group developed severe and persistent pyrexia and dyspnea; mortality between 10 and 20 days was \u3e90% and was associated with severe interstitial pneumonia and/or hepatitis. We conclude that 1) PCV2 alone can induce clinical disease and lesions of PMWS in CD/CD pigs, 2) PCV2 alone does not induce significant respiratory disease in CD/CD pigs, 3) PCV2/PRRSV coinfection induces more severe clinical disease and lesions of PMWS than PCV2 alone, including severe interstitial pneumonia, and 4) PCV2 coinfection is responsible for the hepatitis associated with cases of “atypical PRRS.” Simultaneous coinfection of PRRSV and PCV2 has the potential to significantly exacerbate morbidity and mortality. The timing of exposure and decay of maternal antibody to PCV2 and other pathogens may play a critical role in determining whether PCV2 infection induces PMWS or remains subclinical

    Bayesian Computing with INLA: A Review

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    The key operation in Bayesian inference is to compute high-dimensional integrals. An old approximate technique is the Laplace method or approximation, which dates back to Pierre-Simon Laplace (1774). This simple idea approximates the integrand with a second-order Taylor expansion around the mode and computes the integral analytically. By developing a nested version of this classical idea, combined with modern numerical techniques for sparse matrices, we obtain the approach of integrated nested Laplace approximations (INLA) to do approximate Bayesian inference for latent Gaussian models (LGMs). LGMs represent an important model abstraction for Bayesian inference and include a large proportion of the statistical models used today. In this review, we discuss the reasons for the success of the INLA approach, the R-INLA package, why it is so accurate, why the approximations are very quick to compute, and why LGMs make such a useful concept for Bayesian computing

    Evaluation of a Simplified Measurement for Low Glomerular Filtration Rates With lndium-111 DTPA

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    A rapid new method for measuring glomerular filtration rates using 111In diethylenetriamine pentaacetic acid (111In- DTPA) was evaluated with 39 patients who showed marked impairment of renal function (creatinine clearance less than 20 ml/min). A simple, single compartment system was assumed. For comparison, parallel inulin and creatinine clearances were performed. High linear correlations (r = 0.96-0.97) were demonstrated when 111In- DTPA clearances were compared with the standard nonisotopic tests. Initial data indicate that reliable isotopic clearance values could be obtained for low clearances by withdrawing only two blood samples for assay at 6 and 48 hours after isotope injection (without urine assay)

    Immunologic and virologic findings in a bull chronically infected with noncytopathic bovine viral diarrhea virus

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    In February 1985, a 2-year-old bull with inappetence and weight loss of 1-week duration was examined by the field services staff of the Iowa State University College of Veterinary Medicine. The bull had a normal rectal temperature, decreased rumen activity, and loose feces and walked with a stiff gait. The hemogram was normal for hemoglobin concentration, PCV, and total plasma protein concentration, but the bull had a leukopenia which was primarily attributable to an absolute lymphopenia. Treatment consisted of antimicrobial drugs, an antidiarrheal medication, and a nonsteroidal anti-inflammatory and analgesic drug. After 3 weeks without improvement, the bull was admitted to the Iowa State University Large Animal Hospital

    The use of quantitative Real-Time PCR to estimate Salmonella shed in fecal samples from naturally infected finishing pigs

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    The objective of this study was to describe the shedding pattern of Salmonella in finishing pigs, as well to quantify the Salmonella load. A longitudinal study was conducted in 12 cohorts of pigs in a multi-site farrow-to-finish production system. At the beginning of each cohort, 50 pigs (10 ± 2 weeks old) were randomly selected and individually identified. Individual pig fecal samples were collected and cultured every 2 weeks for 16 weeks (8 collections)
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