239 research outputs found

    ARES I Aerodynamic Testing at the NASA Langley Unitary Plan Wind Tunnel

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    Small-scale force and moment and pressure models based on the outer mold lines of the Ares I design analysis cycle crew launch vehicle were tested in the NASA Langley Research Center Unitary Plan Wind Tunnel from May 2006 to September 2009. The test objectives were to establish supersonic ascent aerodynamic databases and to obtain force and moment, surface pressure, and longitudinal line-load distributions for comparison to computational predictions. Test data were obtained at low through high supersonic Mach numbers for ranges of the Reynolds number, angle of attack, and roll angle. This paper focuses on (1) the sensitivity of the supersonic aerodynamic characteristics to selected protuberances, outer mold line changes, and wind tunnel boundary layer transition techniques, (2) comparisons of experimental data to computational predictions, and (3) data reproducibility. The experimental data obtained in the Unitary Plan Wind Tunnel captured the effects of evolutionary changes to the Ares I crew launch vehicle, exhibited good agreement with predictions, and displayed satisfactory within-test and tunnel-to-tunnel data reproducibility

    Distribution of Brugia malayi larvae and DNA in vector and non-vector mosquitoes: implications for molecular diagnostics

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    <p>Abstract</p> <p>Background</p> <p>The purpose of this study was to extend prior studies of molecular detection of <it>Brugia malayi </it>DNA in vector (<it>Aedes aegypti- </it>Liverpool) and non-vector (<it>Culex pipiens</it>) mosquitoes at different times after ingestion of infected blood.</p> <p>Results</p> <p>Parasite DNA was detected over a two week time course in 96% of pooled thoraces of vector mosquitoes. In contrast, parasite DNA was detected in only 24% of thorax pools from non-vectors; parasite DNA was detected in 56% of midgut pools and 47% of abdomen pools from non-vectors. Parasite DNA was detected in vectors in the head immediately after the blood meal and after 14 days. Parasite DNA was also detected in feces and excreta of the vector and non-vector mosquitoes which could potentially confound results obtained with field samples. However, co-housing experiments failed to demonstrate transfer of parasite DNA from infected to non-infected mosquitoes. Parasites were also visualized in mosquito tissues by immunohistololgy using an antibody to the recombinant filarial antigen Bm14. Parasite larvae were detected consistently after mf ingestion in <it>Ae. aegypti- </it>Liverpool. Infectious L3s were seen in the head, thorax and abdomen of vector mosquitoes 14 days after Mf ingestion. In contrast, parasites were only detected by histology shortly after the blood meal in <it>Cx. pipiens</it>, and these were not labeled by the antibody.</p> <p>Conclusion</p> <p>This study provides new information on the distribution of filarial parasites and parasite DNA in vector and non-vector mosquitoes. This information should be useful for those involved in designing and interpreting molecular xenomonitoring studies.</p

    The Transition from Practitioner to Professor: The Struggle of New Faculty to Find their Place in the World of Academia

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    Becoming a college professor brings both the feeling of self-accomplishment and discernment regarding this prestigious achievement. Most doctoral candidates are practitioners in the eld of public education and will hopefully transition from a principalship to the oce of a college professor. While this journey is lled with personal attainment, some of the doctoral graduates experience a variety of struggles along the way to their positions in higher education. This study examined this journey for some of those who have made the move. The questions posed to the participants centered on the benefits, disadvantages, and suggestions on ways to assist fellow completers who have decided to take a position in higher education. Four primary struggles were identied as a result of the study: (1) struggle with the role, (2) struggle with self, (3) cultural struggle, and (4) future struggles. Through a narrative approach, the participants addressed their feelings regarding the move to a professorship, struggles they faced along the way and the impact the professional change had on their lives

    Persistence of Brugia malayi DNA in vector and non-vector mosquitoes: Implications for xenomonitoring and transmission monitoring of lymphatic filariasis

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    Abstract. Xenomonitoring (detection of filarial larvae or their DNA in mosquitoes) is a sensitive marker for as-sessing the endemicity of filariasis and a useful tool for evaluating elimination programs. To examine the fate of microfilariae (mf) and filarial DNA in vector competent and non-competent mosquito strains, we compared the detec-tion of Brugia malayi parasites by dissection and by quantitative real-time polymerase chain reaction (PCR) in three different mosquito strains. We conclude that PCR is much more sensitive than dissection for detecting filarial larvae, especially their remnants in mosquitoes. However, parasite DNA can be detected in both vector and non-vector mosquitoes for two weeks or longer after they ingest mf-positive blood. Thus, although xenomonitoring with vector and non-vector mosquito species may be a sensitive method for indirectly detecting filarial parasites in human populations, positive test results for parasite DNA in mosquitoes do not necessarily prove that transmission is ongoing in the study area

    Nondestructive Evaluation of Standing Trees With a Stress Wave Method

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    The primary objective of this study was to investigate the usefulness of a stress wave technique for evaluating wood strength and stiffness of young-growth western hemlock and Sitka spruce in standing trees. A secondary objective was to determine if the effects of silvicultural practices on wood quality can be identified using this technique. Stress wave measurements were conducted on 168 young-growth western hemlock and Sitka spruce trees. After in situ measurements, a 0.61-m-long bole section in the test span was taken from 56 felled trees to obtain small, clear wood specimens. Stress wave and static bending tests were then performed on these specimens to determine strength and stiffness. Results of this study indicate that in situ stress wave measurements could provide relatively accurate and reliable information that would enable nondestructive evaluation of wood properties in standing trees. The mean values of stress wave speed and dynamic modulus of elasticity for trees agreed with those determined from small, clear wood specimens. Statistical regression analyses revealed good correlations between stress wave properties of trees and static bending properties of small, clear wood specimens obtained from the trees. Regression models showed statistical significance at the 0.01 confidence level. Results of this study also demonstrate that the effect of silvicultural practices on wood properties can be identified with the stress wave properties of trees. This indicates that this nondestructive stress wave technique can be used to track property changes in trees and help determine how forests could be managed to meet desired wood and fiber qualities

    Effects of Optaflexx Fed in Combination with MGA on Feedlot Heifer Performance

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    A commercial feedlot experiment was conducted using 1,807 heifers to evaluate the effects of Optaflexx fed in combination with MGA on finishing heifer performance. In heifers receiving MGA throughout the entire 126-143 day feeding period, feeding Optaflexx for the last 31-38 days increased ADG and hot carcass weight compared to heifers fed MGA but not Optaflexx. Heifers fed MGA and Optaflexx had increased DMI, improved feed efficiency and increased final live weight. Carcass quality measurements were not influenced by treatment

    A Comparison of Synovex ONE® Alone to Synovex Choice® Followed by Synovex Plus® as Implant Strategies for Finishing Heifers

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    A commercial feedlot study utilizing 1,737 crossbred heifers (initial BW 690 lb) compared the effect of two implant strategies [Synovex ONE Feedlot (day 0) or Synovex Choice (day 0) followed by Synovex Plus (day 95)] on performance and carcass characteristics. No differences were observed in carcass weight, final body weight, or gain, but heifers implanted with Synovex ONE Feedlot had slightly greater feed conversion and greater intake than heifers implanted using Synovex Choice/Synovex Plus. Heifers implanted with Synovex Choice/Synovex Plus had lower marbling score and yield grade, higher dressing percentage, and greater loin muscle area compared to heifers implanted with Synovex ONE Feedlot. Cattle implanted with Synovex ONE Feedlot showed a tendency for better quality grading compared to heifers implanted with Synovex Choice/Synovex Plus. These data suggest that implanting heifers with Synovex ONE Feedlot gives comparable growth to heifers implanted with Synovex Choice followed by Synovex Plus, with some changes in fatness when fed equal days

    Precision Measurement of the Weak Mixing Angle in Moller Scattering

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    We report on a precision measurement of the parity-violating asymmetry in fixed target electron-electron (Moller) scattering: A_PV = -131 +/- 14 (stat.) +/- 10 (syst.) parts per billion, leading to the determination of the weak mixing angle \sin^2\theta_W^eff = 0.2397 +/- 0.0010 (stat.) +/- 0.0008 (syst.), evaluated at Q^2 = 0.026 GeV^2. Combining this result with the measurements of \sin^2\theta_W^eff at the Z^0 pole, the running of the weak mixing angle is observed with over 6 sigma significance. The measurement sets constraints on new physics effects at the TeV scale.Comment: 4 pages, 2 postscript figues, submitted to Physical Review Letter

    Training of Instrumentalists and Development of New Technologies on SOFIA

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    This white paper is submitted to the Astronomy and Astrophysics 2010 Decadal Survey (Astro2010)1 Committee on the State of the Profession to emphasize the potential of the Stratospheric Observatory for Infrared Astronomy (SOFIA) to contribute to the training of instrumentalists and observers, and to related technology developments. This potential goes beyond the primary mission of SOFIA, which is to carry out unique, high priority astronomical research. SOFIA is a Boeing 747SP aircraft with a 2.5 meter telescope. It will enable astronomical observations anywhere, any time, and at most wavelengths between 0.3 microns and 1.6 mm not accessible from ground-based observatories. These attributes, accruing from the mobility and flight altitude of SOFIA, guarantee a wealth of scientific return. Its instrument teams (nine in the first generation) and guest investigators will do suborbital astronomy in a shirt-sleeve environment. The project will invest $10M per year in science instrument development over a lifetime of 20 years. This, frequent flight opportunities, and operation that enables rapid changes of science instruments and hands-on in-flight access to the instruments, assure a unique and extensive potential - both for training young instrumentalists and for encouraging and deploying nascent technologies. Novel instruments covering optical, infrared, and submillimeter bands can be developed for and tested on SOFIA by their developers (including apprentices) for their own observations and for those of guest observers, to validate technologies and maximize observational effectiveness.Comment: 10 pages, no figures, White Paper for Astro 2010 Survey Committee on State of the Professio

    The mass renormalization of nonperturbative light-front Hamiltonian theory: An illustration using truncated, Pauli-Villars-regulated Yukawa interactions

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    We obtain analytic, nonperturbative, approximate solutions of Yukawa theory in the one-fermion sector using light-front quantization. The theory is regulated in the ultraviolet by the introduction of heavy Pauli-Villars scalar and fermion fields, each with negative norm. In order to obtain a directly soluble problem, fermion-pair creation and annihilation are neglected, and the number of bosonic constituents is limited to one of either type. We discuss some of the features of the wave function of the eigensolution, including its endpoint behavior and spin and orbital angular momentum content. The limit of infinite Pauli-Villars mass receives special scrutiny.Comment: Revision includes new title, expanded introduction, and new Figs. 1 &
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