2,318 research outputs found
Measurement of the permeability of tungsten to hydrogen and to oxygen Final report
Permeation rate measurements of hydrogen and oxygen through tungsten at elevated temperature
Measurement of the permeability of tungsten to nitrogen Final report
Permeation of nitrogen through arc-cast tungste
Osteonectin, bone proteoglycan, and phosphophoryn defects in a form of bovine osteogenesis imperfecta.
The Local Interstellar Ultraviolet Radiation Field
I have used the Hipparcos Input Catalog, together with Kurucz model stellar
atmospheres, and information on the strength of the interstellar extinction, to
create a model of the expected intensity and spectral distribution of the local
interstellar ultraviolet radiation field, under various assumptions concerning
the albedo a of the interstellar grains. (This ultraviolet radiation field is
of particular interest because of the fact that ultraviolet radiation is
capable of profoundly affecting the chemistry of the interstellar medium.) By
comparing my models with the observations, I am able to conclude that the
albedo a of the interstellar grains in the far ultraviolet is very low, perhaps
a = 0.1. I also advance arguments that my present determination of this albedo
is much more reliable than any of the many previous (and conflicting)
ultraviolet interstellar grain albedo determinations. Beyond this, I show that
the ultraviolet background radiation that is observed at high galactic
latitudes must be extragalactic in origin, as it cannot be backscatter of the
interstellar radiation field.Comment: Astrophysical Journal, in press; 9 figures + 16 text page
Target company cross-border effects in acquisitions into the UK
We analyse the abnormal returns to target shareholders in crossborder and domestic acquisitions of UK companies. The crossborder effect during the bid month is small (0.84%), although crossborder targets gain significantly more than domestic targets during the months surrounding the bid. We find no evidence for the level of abnormal returns in crossborder acquisitions to be associated with market access or exchange rate effects, and only limited support for an international diversification effect. However, the crossborder effect appears to be associated with significant payment effects, and there is no significant residual crossborder effect once various bid characteristics are controlled for
Swimming like algae: biomimetic soft artificial cilia
Cilia are used effectively in a wide variety of biological systems from fluid transport to thrust generation. Here, we present the design and implemen- tation of artificial cilia, based on a biomimetic planar actuator using soft- smart materials. This actuator is modelled on the cilia movement of the alga Volvox, and represents the cilium as a piecewise constant-curvature robotic actuator that enables the subsequent direct translation of natural articulation into a multi-segment ionic polymer metal composite actuator. It is demonstrated how the combination of optimal segmentation pattern and biologically derived per-segment driving signals reproduce natural cili- ary motion. The amenability of the artificial cilia to scaling is also demonstrated through the comparison of the Reynolds number achieved with that of natural cilia
Politics, resistance and patronage: the African boycott of the 1966 World Cup and its ramifications
Anopheles aquasalis Eggs from Two Venezuelan Localities Compared by Scanning Electron Microscopy
The effectiveness of interventions to change six health behaviours: a review of reviews
Background: Several World Health Organisation reports over recent years have highlighted the high incidence of chronic diseases such as diabetes, coronary heart disease and cancer. Contributory factors include unhealthy diets, alcohol and tobacco use and sedentary lifestyles. This paper reports the findings of a review of reviews of behavioural change interventions to reduce unhealthy behaviours or promote healthy behaviours. We included six different health-related behaviours in the review: healthy eating, physical exercise, smoking, alcohol misuse, sexual risk taking (in young people) and illicit drug use. We excluded reviews which focussed on pharmacological treatments or those which required intensive treatments (e. g. for drug or alcohol dependency).
Methods: The Cochrane Library, Database of Abstracts of Reviews of Effectiveness (DARE) and several Ovid databases were searched for systematic reviews of interventions for the six behaviours (updated search 2008). Two reviewers applied the inclusion criteria, extracted data and assessed the quality of the reviews. The results were discussed in a narrative synthesis.
Results: We included 103 reviews published between 1995 and 2008. The focus of interventions varied, but those targeting specific individuals were generally designed to change an existing behaviour (e. g. cigarette smoking, alcohol misuse), whilst those aimed at the general population or groups such as school children were designed to promote positive behaviours (e. g. healthy eating). Almost 50% (n = 48) of the reviews focussed on smoking (either prevention or cessation). Interventions that were most effective across a range of health behaviours included physician advice or individual counselling, and workplace- and school-based activities. Mass media campaigns and legislative interventions also showed small to moderate effects in changing health behaviours. Generally, the evidence related to short-term effects rather than sustained/longer-term impact and there was a relative lack of evidence on how best to address inequalities.
Conclusions: Despite limitations of the review of reviews approach, it is encouraging that there are interventions that are effective in achieving behavioural change. Further emphasis in both primary studies and secondary analysis (e.g. systematic reviews) should be placed on assessing the differential effectiveness of interventions across different population subgroups to ensure that health inequalities are addressed.</p
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