3,586 research outputs found
State-of-the-art survey of dissimilar metal joining by solid state welding
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
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
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
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
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
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Development of variable-width ribbon heating elements for liquid-metal and gas-cooled fast breeder reactor fuel-pin simulators
Variable-width ribbon heating elements that provide a chopped-cosine variable heat flux profile have been fabricated for fuel pin simulators used in test loops by the Breeder Reactor Program Thermal-Hydraulic Out-of-Reactor Safety test facility and the Gas-Cooled Fast Breeder Reactor-Core Flow Test Loop. Thermal, mechanical, and electrical design considerations are used to derive an analytical expression that precisely describes ribbon contour in terms of the major fabrication parameters. These parameters are used to generate numerical control tapes that control ribbon cutting and winding machines. Infrared scanning techniques are developed to determine the optimum transient thermal profile of the coils and relate this profile to that generated by the coils in completed fuel pin simulators
Recommended from our members
Development of variable width ribbon heating elements for liquid metal and gas-cooled fast breeder reactor fuel rod simulators
Variable width ribbon heating elements have been fabricated which provide a chopped cosine, variable heat flux profile for fuel rod simulators used in test loops by the Breeder Reactor Program Thermal Hydraulic Out-of-Reactor Safety test facility and the Gas-Cooled Fast Breeder Reactor Core Flow Test Loop. Thermal, mechanical, and electrical design considerations result in the derivation of an analytical expression for the ribbon contours. From this, the ribbons are machined and wound on numerically controlled equipment. Postprocessing and inspection results in a wound, variable width ribbon with the precise dimensional, electrical, and mechanical properties needed for use in fuel pin simulators
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
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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