1,988 research outputs found

    The upper critical field of filamentary Nb3Sn conductors

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    We have examined the upper critical field of a large and representative set of present multi-filamentary Nb3Sn wires and one bulk sample over a temperature range from 1.4 K up to the zero field critical temperature. Since all present wires use a solid-state diffusion reaction to form the A15 layers, inhomogeneities with respect to Sn content are inevitable, in contrast to some previously studied homogeneous samples. Our study emphasizes the effects that these inevitable inhomogeneities have on the field-temperature phase boundary. The property inhomogeneities are extracted from field-dependent resistive transitions which we find broaden with increasing inhomogeneity. The upper 90-99 % of the transitions clearly separates alloyed and binary wires but a pure, Cu-free binary bulk sample also exhibits a zero temperature critical field that is comparable to the ternary wires. The highest mu0Hc2 detected in the ternary wires are remarkably constant: The highest zero temperature upper critical fields and zero field critical temperatures fall within 29.5 +/- 0.3 T and 17.8 +/- 0.3 K respectively, independent of the wire layout. The complete field-temperature phase boundary can be described very well with the relatively simple Maki-DeGennes model using a two parameter fit, independent of composition, strain state, sample layout or applied critical state criterion.Comment: Accepted Journal of Applied Physics Few changes to shorten document, replaced eq. 7-

    Non-Thermal Continuum toward SGRB2(N-LMH)

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    An analysis of continuum antenna temperatures observed in the Green Bank Telescope (GBT) spectrometer bandpasses is presented for observations toward SgrB2(N-LMH). Since 2004, we have identified four new prebiotic molecules toward this source by means of rotational transitions between low energy levels; concurrently, we have observed significant continuum in the GBT spectrometer bandpasses centered at 85 different frequencies in the range of 1 to 48 GHz. The continuum heavily influences the molecular spectral features since we have observed far more absorption lines than emission lines for each of these new molecular species. Hence, it is important to understand the nature, distribution, and intensity of the underlying continuum in the GBT bandpasses for the purposes of radiative transfer, i.e. the means by which reliable molecular abundances are estimated. We find that the GBT spectrometer bandpass continuum is consistent with optically-thin, non thermal (synchrotron) emission with a flux density spectral index of -0.7 and a Gaussian source size of ~143" at 1 GHz that decreases with increasing frequency as nu^(-0.52). Some support for this model is provided by high frequency Very Large Array (VLA) observations of SgrB2.Comment: Accepted for Publication in the Astrophysical Journal Letter

    Effectiveness of group-based self-management education for individuals with Type 2 diabetes:A systematic review with meta-analyses and meta-regression

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    Aims: Patient education for the management of Type 2 diabetes can be delivered in various forms, with the goal of promoting and supporting positive self-management behaviours. This systematic review aimed to determine the effectiveness of group-based interventions compared with individual interventions or usual care for improving clinical, lifestyle and psychosocial outcomes in people with Type 2 diabetes. Methods: Six electronic databases were searched. Group-based education programmes for adults with Type 2 diabetes that measured glycated haemoglobin (HbA1c) and followed participants for ≥ 6 months were included. The primary outcome was HbA1c, and secondary outcomes included fasting blood glucose, weight, body mass index, waist circumference, blood pressure, blood lipid profiles, diabetes knowledge and self-efficacy. Results: Fifty-three publications describing 47 studies were included (n = 8533 participants). Greater reductions in HbA1c occurred in group-based education compared with controls at 6–10 months [n = 30 studies; mean difference (MD) = 3 mmol/mol (0.3%); 95% confidence interval (CI): −0.48, −0.15; P = 0.0002], 12–14 months [n = 27 studies; MD = 4 mmol/mol (0.3%); 95% CI: −0.49, −0.17; P < 0.0001], 18 months [n = 3 studies; MD = 8 mmol/mol (0.7%); 95% CI: −1.26, −0.18; P = 0.009] and 36–48 months [n = 5 studies; MD = 10 mmol/mol (0.9%); 95% CI: −1.52, −0.34; P = 0.002], but not at 24 months. Outcomes also favoured group-based education for fasting blood glucose, body weight, waist circumference, triglyceride levels and diabetes knowledge, but not at all time points. Interventions facilitated by a single discipline, multidisciplinary teams or health professionals with peer supporters resulted in improved outcomes in HbA1c when compared with peer-led interventions. Conclusions: Group-based education interventions are more effective than usual care, waiting list control and individual education at improving clinical, lifestyle and psychosocial outcomes in people with Type 2 diabetes.No Full Tex

    Development of automatic and manual flight director landing systems for the XV-15 tilt rotor aircraft in helicopter mode

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    The objective of this effort is to determine IFR approach path and touchdown dispersions for manual and automatic XV-15 tilt rotor landings, and to develop missed approach criteria. Only helicopter mode XV-15 operation is considered. The analysis and design sections develop the automatic and flight director guidance equations for decelerating curved and straight-in approaches into a typical VTOL landing site equipped with an MLS navigation aid. These system designs satisfy all known pilot-centered, guidance and control requirements for this flying task. Performance data, obtained from nonstationary covariance propagation dispersion analysis for the system, are used to develop the approach monitoring criteria. The autoland and flight director guidance equations are programmed for the VSTOLAND 1819B digital computer. The system design dispersion data developed through analysis and the 1819B digital computer program are verified and refined using the fixed-base, man-in-the-loop XV-15 VSTOLAND simulation

    Ground-State SiO Maser Emission Toward Evolved Stars

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    We have made the first unambiguous detection of vibrational ground-state maser emission from SiO toward six evolved stars. Using the Very Large Array, we simultaneously observed the v=0, J=1-0, 43.4-GHz, ground-state and the v=1, J=1-0, 43.1-GHz, first excited-state transitions of SiO toward the oxygen-rich evolved stars IRC+10011, o Ceti, W Hya, RX Boo, NML Cyg, and R Cas and the S-type star chi Cyg. We detected at least one v=0 SiO maser feature from six of the seven stars observed, with peak maser brightness temperatures ranging from 10,000 K to 108,800 K. In fact, four of the seven v=0 spectra show multiple maser peaks, a phenomenon which has not been previously observed. Ground-state thermal emission was detected for one of the stars, RX Boo, with a peak brightness temperature of 200 K. Comparing the v=0 and the v=1 transitions, we find that the ground-state masers are much weaker with spectral characteristics different from those of the first excited-state masers. For four of the seven stars the velocity dispersion is smaller for the v=0 emission than for the v=1 emission, for one star the dispersions are roughly equivalent, and for two stars (one of which is RX Boo) the velocity spread of the v=0 emission is larger. In most cases, the peak flux density in the v=0 emission spectrum does not coincide with the v=1 maser peak. Although the angular resolution of these VLA observations were insufficient to completely resolve the spatial structure of the SiO emission, the SiO spot maps produced from the interferometric image cubes suggest that the v=0 masers are more extended than their v=1 counterparts

    The effect of interleukin-10 and transforming growth factor beta-1 on HLA-DR expression in colonic epithelial cells.

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    The aim of this study was to assess whether interleukin-10 (IL-10) and/or transforming growth factor beta-1 (TGFbeta1) downregulate HLA-DR expression using the HT29 cell line as a model of colonic epithelial cells. HLA-DR expression was induced in HT29 cells with gamma-interferon. The effects of IL-10 alone, TGFbeta1 alone, and IL-10 and TGFbeta1 in combination were studied. HLA-DR expression was assessed using flow cytometric analysis. Gamma-interferon induced HLA-DR expression in a dose-dependent fashion. In the absence of gamma-interferon, neither IL-10 nor TGFbeta1 induced HLA-DR expression. In isolation, neither IL-10 nor TGFbeta1 downregulated HLA-DR expression. When IL-10 and TGFbeta1 were added in combination, small (6-30%) statistically significant reductions in HLA-DR expression were seen. The biological significance is unclear

    Penal characteristics as predictors of depression in a Southern Nigerian prison

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    This study examined the penal characteristics acting as predictors of depressive disorders among 400 prison inmates using the stratified random sampling technique and the Depression component of WHO Schedule for Clinical Assessment in Neuropsychiatry (SCAN). Data analysis was performed with the SPSS software package (Version 17) with the test of significance set at p&lt;0.05. Results revealed a prevalence of 14.8% mild depression; 14.2% moderate depression with somatic features; 6.2% severe depression without psychotic features; 4.5% severe depression with psychotic features and an overall prevalence of 37%. Significant penal factors were nature of crime, reasons for delay in trial, and duration of stay. `The most frequently violated criminal code was Criminal code 401 (Armed Robbery). Logistic regression analysis indicated that the strongest predictor of depression was the duration of time spent in prison (or: 1.43, ci=1.19-1.73, p=0.00). Our findings suggest that duration of stay in prison increases the risk of depression among inmates and that the penal predictors for depression during imprisonment could help identify people for mental health interventions. It is recommended that concerned agencies of government should, as a matter of urgent public health importance, consider reforming the criminal justice system to reduce the duration of  stay in prisons.Keywords: Crime, penal, depression, offender, prison population

    Discovery of the Interstellar Chiral Molecule Propylene Oxide (CH3_3CHCH2_2O)

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    Life on Earth relies on chiral molecules, that is, species not superimposable on their mirror images. This manifests itself in the selection of a single molecular handedness, or homochirality, across the biosphere. We present the astronomical detection of a chiral molecule, propylene oxide (CH3_3CHCH2_2O), in absorption toward the Galactic Center. Propylene oxide is detected in the gas phase in a cold, extended molecular shell around the embedded, massive protostellar clusters in the Sagittarius B2 star-forming region. This material is representative of the earliest stage of solar system evolution in which a chiral molecule has been found

    Workshop on Structural Dynamics and Control Interaction of Flexible Structures

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    The Hubble Space Telescope features the most exacting line of sight jitter requirement thus far imposed on a spacecraft pointing system. Consideration of the fine pointing requirements prompted an attempt to isolate the telescope from the low level vibration disturbances generated by the attitude control system reaction wheels. The primary goal was to provide isolation from axial component of wheel disturbance without compromising the control system bandwidth. A passive isolation system employing metal springs in parallel with viscous fluid dampers was designed, fabricated, and space qualified. Stiffness and damping characteristics are deterministic, controlled independently, and were demonstrated to remain constant over at least five orders of input disturbance magnitude. The damping remained purely viscous even at the data collection threshold of .16 x .000001 in input displacement, a level much lower than the anticipated Hubble Space Telescope disturbance amplitude. Vibration attenuation goals were obtained and ground test of the vehicle has demonstrated the isolators are transparent to the attitude control system
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