3,586 research outputs found

    State-of-the-art survey of dissimilar metal joining by solid state welding

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    State-of-the-art of dissimilar metal joining by solid state diffusion bonding and roll and press welding, emphasizing stainless steel and aluminum allo

    Angular Broadening of Intraday Variable AGN. II. Interstellar and Intergalactic Scattering

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    We analyze a sample of 58 multi-wavelength, Very Long Baseline Array observations of active galactic nuclei (AGN) to determine their scattering properties. Approximately 75% of the sample consists of AGN that exhibit centimeter-wavelength intraday variability (interstellar scintillation) while the other 25% do not show intraday variability. We find that interstellar scattering is measurable for most of these AGN, and the typical broadening diameter is 2 mas at 1 GHz. We find that the scintillating AGN are typically at lower Galactic latitudes than the non-scintillating AGN, consistent with the scenario that intraday variability is a propagation effect from the Galactic interstellar medium. The magnitude of the inferred interstellar broadening measured toward the scintillating AGN, when scaled to higher frequencies, is comparable to the diameters inferred from analyses of the light curves for the more well-known intraday variable sources. However, we find no difference in the amount of scattering measured toward the scintillating versus non-scintillating AGN. A consistent picture is one in which the scintillation results from localized regions ("clumps") distributed throughout the Galactic disk, but which individually make little contribution to the angular broadening. Of the 58 AGN observed, 37 (64%) have measured redshifts. At best, a marginal trend is found for scintillating (non-scintillating) AGN to have smaller (larger) angular diameters at higher redshifts. We also use our observations to try to constrain the possibility of intergalactic scattering. While broadly consistent with the scenario of a highly turbulent intergalactic medium, our observations do not place significant constraints on its properties.Comment: 13 pages, 4 figures; AASTeX format; ApJ in pres

    Australian survey of current practice and guideline use in adult cancer pain assessment and management: Perspectives of oncologists

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    Aims: Cancer pain continues to be undertreated in up to half of cases, despite the availability of evidence-based guidelines. This study aimed to: (i) identify barriers and facilitators to adult cancer pain assessment and management, as perceived by Australian health professionals; (ii) establish the perceived need for new Australian guidelines and implementation strategy; (iii) identify which guidelines are used; (iv) identify barriers and facilitators to guideline use. This article focuses on the perceptions of responding oncologists. Methods: A cross-sectional survey was administered online. Invitations were circulated via peak bodies and clinical leaders. Comments were coded independently by two researchers. Results: In all 76 oncologists self-reported high concordance with evidence-based recommendations, except validated pain scales. Perceived barriers to pain management included insufficient non-pharmacological interventions, access to /coordination between services, and time. Only 22 percent of respondents reported using pain guidelines. Perceived barriers to guideline use included lack of access, awareness and any single standard. Respondents were generally supportive of new Australian guidelines and especially an implementation strategy. Conclusion: Barriers to evidence-based practice and guideline use identified by our survey might be addressed via a clinical pathway that gives step-by-step guidance on evidence-based practice along with a framework for evaluation. Particular attention should be paid to promoting use of validated scales, patient education and non-pharmacological interventions, training of an appropriately skilled workforce and improving care coordination. Challenges are discussed. © 2012 Wiley Publishing Asia Pty Ltd

    Venus Express radio occultation observed by PRIDE

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    Context. Radio occultation is a technique used to study planetary atmospheres by means of the refraction and absorption of a spacecraft carrier signal through the atmosphere of the celestial body of interest, as detected from a ground station on Earth. This technique is usually employed by the deep space tracking and communication facilities (e.g., NASA's Deep Space Network (DSN), ESA's Estrack). Aims. We want to characterize the capabilities of the Planetary Radio Interferometry and Doppler Experiment (PRIDE) technique for radio occultation experiments, using radio telescopes equipped with Very Long Baseline Interferometry (VLBI) instrumentation. Methods. We conducted a test with ESA's Venus Express (VEX), to evaluate the performance of the PRIDE technique for this particular application. We explain in detail the data processing pipeline of radio occultation experiments with PRIDE, based on the collection of so-called open-loop Doppler data with VLBI stations, and perform an error propagation analysis of the technique. Results. With the VEX test case and the corresponding error analysis, we have demonstrated that the PRIDE setup and processing pipeline is suited for radio occultation experiments of planetary bodies. The noise budget of the open-loop Doppler data collected with PRIDE indicated that the uncertainties in the derived density and temperature profiles remain within the range of uncertainties reported in previous Venus' studies. Open-loop Doppler data can probe deeper layers of thick atmospheres, such as that of Venus, when compared to closed-loop Doppler data. Furthermore, PRIDE through the VLBI networks around the world, provides a wide coverage and range of large antenna dishes, that can be used for this type of experiments

    Collective enhancement in the exciton model

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    The pre-equilibrium reaction mechanism is considered in the context of the exciton model. A modification to the one-particle one-hole state density is studied which can be interpreted as a collective enhancement. The magnitude of the collective enhancement is set by simulating the Lawrence Livermore National Laboratory (LLNL) pulsed-spheres neutron-leakage spectra. The impact of the collective enhancement is explored in the context of the highly deformed actinide, 239-Pu. A consequence of this enhancement is the removal of fictitious levels in the Distorted-Wave Born Approximation often used in modern nuclear reaction codes.Comment: 7 pages, 7 figures. Comments welcome

    The cyclin-dependent kinase inhibitor p57(Kip2) is epigenetically regulated in carboplatin resistance and results in collateral sensitivity to the CDK inhibitor seliciclib in ovarian cancer

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    Carboplatin remains a first-line agent in the management of epithelial ovarian cancer (EOC). Unfortunately, platinum-resistant disease ultimately occurs in most patients. Using a novel EOC cell line with acquired resistance to carboplatin: PEO1CarbR, genome-wide micro-array profiling identified the cyclin-dependent kinase inhibitor p57(Kip2) as specifically downregulated in carboplatin resistance. Presently, we describe confirmation of these preliminary data with a variety of approaches
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