6,531 research outputs found
Evaluation of the effects of a freeze/thaw environment on cellular glass
Using the evaluation criteria of water vapor permeability and conformability, a protective butylrubber/silicone conformal coating system was selected for use on Foamglas substrates in a freeze/thaw environment. The selection of a specific freeze/thaw cycle which closely models field conditions is discussed. A sampling plan is described which allows independent evaluation of the effects of conformal coatings, cycle number and location within the environmental chamber. The results of visual examination, measurement of density, modulus of rupture and Young's modulus are reported. Based upon statistical evaluation of the experimental results, it is concluded that no degradation in mechanical properties of either coated or uncoated Foamglas occurred within the duration of the test (53 freeze/thaw cycles)
Does perceived organisational support influence career intentions?:The qualitative stories shared by UK early career doctors
Our thanks to all those FP2 doctors who participated in the interviews. Our thanks also to the Foundation Programme Directorate staff in the Scotland Deanery, NHS Education for Scotland, for sending out the email correspondence to the two regions involved in the interviews. No patients or any members of the public were involved in this study. Funding: Our thanks go to NHS Education for Scotland for funding Gillian Scanlan’s programme of work through the Scottish Medical Education Research Consortium (SMERC) and for funding the open-access fee for this paper.Peer reviewedPublisher PD
Does initial postgraduate career intention and social demographics predict perceived career behaviour?:A national cross-sectional survey of UK postgraduate doctors
Acknowledgements: Our thanks to all those FP2 doctors who participated in the survey. Our thanks also to the Foundation Programme Directors across the UK for allowing permission to conduct research on this data set. No patients or any members of the public were involved in this study. Funding: Our thanks go to NHS Education for Scotland for funding Gillian Scanlan’s programme of work through the Scottish Medical Education Research Consortium (SMERC). Data sharing statement: The data reported is from the UKFPO dataset, and any data shared would need the permission of the UK Foundation Programme directorsPeer reviewedPublisher PD
Tablet computers in assessing performance in a high stakes exam : opinion matters
The authors would like to thank Dr Craig brown, University of Aberdeen for assistance with data analysis.Peer reviewedPublisher PD
HIV protective strategies among college students in Durban, South Africa
There is growing concern about the high level of HIV infection among young people in South Africa. The aim of the study is to examine the HIV protective strategies used by college students with specific emphasis on variations by race group. The data for the study come from a self-administrated survey that was conducted with 3 000 college students in Durban in order to understand the strategies they use to protect themselves against the risk of HIV infection. Overall, students perceived a far greater risk of pregnancy than HIV infection. The results show that abstinence is the most common protective factor among Indian and White students. Among African students, there is great concern about HIV but abstinence is less common. Among sexually active men and women, the majority report having more than one sexual partner (with the exception of Indian females). Female students among all groups were more likely than male students to report that they were faithful to their partners. In Africans the contrast is stark: 25% for women versus 6% for men. Condoms are the most commonly used method by students but are not used in every sexual encounter. Consistent condom use was highest among Indian males (46%) and lowest among White females (13.7%). More effort needs to be directed at promoting correct and consistent condom use in order to avoid the negative consequences associated with unprotected sexual intercourse including unwanted pregnancy and HIV/AIDS
New ways to visualize and combat congestion in heart failure = Nuevos modos de visualizar y combatir la congestión en la insuficiencia cardiaca
No abstract available
Dissipation in a rotating frame: master equation, effective temperature and Lamb-shift
Motivated by recent realizations of microwave-driven nonlinear resonators in
superconducting circuits, the impact of environmental degrees of freedom is
analyzed as seen from a rotating frame. A system plus reservoir model is
applied to consistently derive in the weak coupling limit the master equation
for the reduced density in the moving frame and near the first bifurcation
threshold. It turns out that additional interactions between momenta of system
and bath appear which have been omitted in previous studies. Explicit
expressions for the effective temperature and the Lamb-shift are given which
for ohmic baths are in agreement with experimental findings, while for
structured environments population inversion is predicted that may
qualitatively explain recent observations.Comment: 7 pages, 5 figure
Electron-phonon coupling and longitudinal mechanical-mode cooling in a metallic nanowire
We investigate electron-phonon coupling in a narrow suspended metallic wire,
in which the phonon modes are restricted to one dimension but the electrons
behave three-dimensionally. Explicit theoretical results related to the known
bulk properties are derived. We find out that longitudinal vibration modes can
be cooled by electronic tunnel refrigeration far below the bath temperature
provided the mechanical quality factors of the modes are sufficiently high. The
obtained results apply to feasible experimental configurations.Comment: 4+ pages, 3 figure
The charge shuttle as a nanomechanical ratchet
We consider the charge shuttle proposed by Gorelik {\em et al.} driven by a
time-dependent voltage bias. In the case of asymmetric setup, the system
behaves as a rachet. For pure AC drive, the rectified current shows a complex
frequency dependent response characterized by frequency locking at fracional
values of the external frequency. Due to the non-linear dynamics of the
shuttle, the rachet effect is present also for very low frequencies.Comment: 4 pages, 4 figure
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