6,734 research outputs found

    Cold dilute neutron matter on the lattice II: Results in the unitary limit

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    This is the second of two papers which investigate cold dilute neutron matter on the lattice using pionless effective field theory. In the unitary limit, where the effective range is zero and scattering length is infinite, simple scaling relations relate thermodynamic functions at different temperatures. When the second virial coefficient is properly tuned, we find that the lattice results obey these scaling relations. We compute the energy per particle, pressure, spin susceptibility, dineutron correlation function, and an upper bound for the superfluid critical temperature.Comment: 16 pages, 9 figure

    Measurement uncertainty for the Uniform Engine Testing Program conducted at NASA Lewis Research Center

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    An uncertainty analysis was conducted to determine the bias and precision errors and total uncertainty of measured turbojet engine performance parameters. The engine tests were conducted as part of the Uniform Engine Test Program which was sponsored by the Advisory Group for Aerospace Research and Development (AGARD). With the same engines, support hardware, and instrumentation, performance parameters were measured twice, once during tests conducted in test cell number 3 and again during tests conducted in test cell number 4 of the NASA Lewis Propulsion Systems Laboratory. The analysis covers 15 engine parameters, including engine inlet airflow, engine net thrust, and engine specific fuel consumption measured at high rotor speed of 8875 rpm. Measurements were taken at three flight conditions defined by the following engine inlet pressure, engine inlet total temperature, and engine ram ratio: (1) 82.7 kPa, 288 K, 1.0, (2) 82.7 kPa, 288 K, 1.3, and (3) 20.7 kPa, 288 K, 1.3. In terms of bias, precision, and uncertainty magnitudes, there were no differences between most measurements made in test cells number 3 and 4. The magnitude of the errors increased for both test cells as engine pressure level decreased. Also, the level of the bias error was two to three times larger than that of the precision error

    A direct bonding system for orthodontic attachments

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    Thesis (M.Sc.D.)--Boston University School of Graduate Dentistry, 1972. (Orthodontics)Bibliography included.A number of adhesive systems for the direct bonding of orthodontic attachments to the tooth surface have been reported during the last five years. The purpose of this investigation is to evalua te clinically a new bonding system which appears to have apparent advantages over previous techniques. Seven months trial of 552 brackets in the mouths of 59 patients is not enough time to completely evaluate the system. However, it appears to have greater stability and durability in the actual treatment of malocclusions than previous techniques. These brackets can withstand comprehensj_ve treatment procedures including the use of extraoral forces and torquing moments. Additionally, these brackets can be placed efficiently and quickly. There are many advantages to such a handless technique to both the patient and the orthodontist. Patient discomfort is minimized by the elimination of "tooth separation" often necessary for band adaptation and -cementation. Stresses on the orthodontist are reduced due to the elimination of banding appointments. Decalcifications, due to disintegration of the cement under the bands, are decreased since there is no partial cement washout without complete dislodgement of the bracket. Gingival irritations are drastically reduced since there are no bands to seat subgingivally. The patient's oral hygiene appears to be improved with the elimination of the bands and aesthetics is greatly improved

    Tree-Soil Interactions Affect Production of Loblolly and Slash Pine

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    Species-related differences in needle litter nutrient concentrations and subsequent N mineralization were examined in 17-year-old stands of loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) at a common site. Results of this common-garden study indicate that a feedback may exist between foliar litter nutrient concentration and soil N mineralization. Net N mineralization (to 30 cm) was significantly greater in loblolly pine than in slash pine stands, which was attributed to greater litter nutrient concentrations in loblolly pine. Stand volume production was also greater in loblolly pine than in slash pine and was positively correlated with N mineralization. Although lower litter nutrient concentrations may have reduced productivity of slash pine relative to loblolly pine in this study, they may serve as a mechanism to increase the relative fitness of the species by lowering the soil nutrient availability below the optimum of loblolly pine

    Study protocol: addressing evidence and context to facilitate transfer and uptake of consultation recording use in oncology: a knowledge translation implementation study

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    Background: The time period from diagnosis to the end of treatment is challenging for newly diagnosed cancer patients. Patients have a substantial need for information, decision aids, and psychosocial support. Recordings of initial oncology consultations improve information recall, reduce anxiety, enhance patient satisfaction with communication, and increase patients' perceptions that the essential aspects of their disease and treatment have been addressed during the consultation. Despite the research evidence supporting the provision of consultation recordings, uptake of this intervention into oncology practice has been slow. The primary aim of this project is to conduct an implementation study to explicate the contextual factors, including use of evidence, that facilitate and impede the transfer and uptake of consultation-recording use in a sample of patients newly diagnosed with breast or prostate cancer. Methods: Sixteen oncologists from cancer centres in three Canadian cities will participate in this three-phase study. The preimplementation phase will be used to identify and address those factors that are fundamental to facilitating the smooth adoption and delivery of the intervention during the implementation phase. During the implementation phase, breast and prostate cancer patients will receive a recording of their initial oncology consultation to take home. Patient interviews will be conducted in the days following the consultation to gather feedback on the benefits of the intervention. Patients will complete the Digital Recording Use Semi-Structured Interview (DRUSSI) and be invited to participate in focus groups in which their experiences with the consultation recording will be explored. Oncologists will receive a summary letter detailing the benefits voiced by their patients. The postimplementation phase includes a conceptual framework development meeting and a seven-point dissemination strategy. Discussion: Consultation recording has been used in oncology, family medicine, and other medicine specialties, and despite affirming evidence and probable applications to a large number of diseases and a variety of clinical contexts, clinical adoption of this intervention has been slow. The proposed study findings will advance our conceptual knowledge of the ways to enhance uptake of consultation recordings in oncology

    Globular Clusters in the dE,N galaxy NGC 3115 DW1: New Insights from Spectroscopy and HST Photometry

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    The properties of globular clusters in dwarf galaxies are key to understanding the formation of globular cluster systems, and in particular in verifying scenarios in which globular cluster systems of larger galaxies formed (at least partly) from the accretion of dwarf galaxies. Here, we revisit the globular cluster system of the dE,N galaxy NGC 3115 DW1 - a companion of the nearby S0 galaxy NGC 3115 - adding Keck/LRIS spectroscopy and HST/WFPC2 imaging to previous ground-based photometry. Spectra for seven globular clusters reveal normal abundance ratios with respect to the Milky Way and M31 clusters, as well as a relatively high mean metallicity ([Fe/H] = -1.0+/-0.1 dex). Crude kinematics indicate a high velocity dispersion within 10 kpc which could either be caused by dark matter dominated outer regions, or by the stripping of outer globular clusters by the nearby giant galaxy NGC 3115. The total galaxy mass out to 3 and 10 kpc lies between 10^10 and 10^11 solar masses and 2*10^10 and 4*10^11 solar masses, respectively, depending on the mass estimator used and the assumptions on cluster orbits and systemic velocity. The HST imaging allows measurement of sizes for two clusters, returning core radii around 2.0 pc, similar to the sizes observed in other galaxies. Spectroscopy allows an estimate of the degree of contamination by foreground stars or background galaxies for the previous ground-based photometry, but does not require a revision of previous results: NGC 3115 DW1 hosts around 60+/-20 clusters which corresponds to a specific frequency of 4.9+/-1.9, on the high end for massive dEs. Given its absolute magnitude (M_V=-17.7 mag) and the properties of its cluster system, NGC 3115 DW1 appears to be a transition between a luminous dE and low-luminosity E galaxy.Comment: 25 pages, 8 figures, accepted for publication in The Astronomical Journal, August 2000 issu
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