28,162 research outputs found
The Least Action Principle And The Spin Of Galaxies In The Local Group
Using Peebles' least action principle, we determine trajectories for the
galaxies in the Local Group and the more massive galaxies in the Local
Neighbourhood. We deduce the resulting angular momentum for the whole of the
Local Group and study the tidal force acting on the Local Group and its
galaxies. Although Andromeda and the Milky Way dominate the tidal force acting
on each other during the present epoch, we show that there is a transition time
at before which the tidal force is dominated by galaxies outside
the Local Group in each case. This shows that the Local Group can not be
considered as an isolated system as far as the tidal forces are concerned. We
integrate the tidal torques acting on the Milky Way and Andromeda and derive
their spin angular momenta, obtaining results which are comparable with
observation.Comment: 16 pages (5 figures available on request), plain TeX, IoA-93-01-AM
Measurement of NO plus plus e minus dissociative recombination in expanding air flows
Measurement of nitric oxide ion-electron dissociative recombination in expanding air flow
Sources of electron energy in weakly ionized expansions of nitrogen
Sources of electron energy in weakly ionized expansions of nitroge
Perceptions of human attractiveness comprising face and voice cues
In human mate choice, sexually dimorphic faces and voices comprise hormone-mediated cues that purportedly develop as an indicator of mate quality or the ability to compete with same-sex rivals. If preferences for faces communicate the same biologically relevant information as do voices, then ratings of these cues should correlate. Sixty participants (30 male and 30 female) rated a series of opposite-sex faces, voices, and faces together with voices for attractiveness in a repeated measures computer-based experiment. The effects of face and voice attractiveness on face-voice compound stimuli were analyzed using a multilevel model. Faces contributed proportionally more than voices to ratings of face-voice compound attractiveness. Faces and voices positively and independently contributed to the attractiveness of male compound stimuli although there was no significant correlation between their rated attractiveness. A positive interaction and correlation between attractiveness was shown for faces and voices in relation to the attractiveness of female compound stimuli. Rather than providing a better estimate of a single characteristic, male faces and voices may instead communicate independent information that, in turn, provides a female with a better assessment of overall mate quality. Conversely, female faces and voices together provide males with a more accurate assessment of a single dimension of mate quality
Feasibility of recruitment to an oral dysplasia trial in the United Kingdom
Background:
Oral epithelial dysplasia (OED) has a malignant potential. Therapeutic options for OED remain both limited and without good evidence. Despite surgery being the most common method of treating OED, recurrence and potentially significant morbidity remain problematic. Consequently, there has been much interest in non-surgical treatments for OED. Cyclo-oxygenase (COX) up-regulation is known to occur in the dysplasia-carcinoma sequence and evidence now exists that COX-2 is a prognostic marker of malignant transformation in OED. COX-inhibitors are therefore considered a potential therapeutic strategy for treating this condition. We aimed to provide both proof of principal evidence supporting the effect of topical COX inhibition, and determine the feasibility of recruitment to an OED chemoprevention trial in the UK.
Methods:
Recruitment of 40 patients with oral leukoplakia to 4 study arms was planned. The total daily dose of Aspirin would increase in each group and be used in the period between initial diagnostic and follow-up biopsies.
Results:
During the 15-month recruitment period, 15/50 screened patients were eligible for recruitment, and 13 (87%) consented. Only 1 had OED diagnosed on biopsy. 16 patients were intolerant of, or already taking Aspirin and 16 patients required no biopsy. Initial recruitment was slow, as detection relied on clinicians identifying potentially eligible patients. Pre-screening new patient letters and directly contacting patients listed for biopsies improved screening of potentially eligible patients. However, as the incidence of OED was so low, it had little impact on trial recruitment. The trial was terminated, as recruitment was unlikely to be achieved in a single centre.
Conclusion:
This feasibility trial has demonstrated the low incidence of OED in the UK and the difficulties in conducting a study because of this. With an incidence of around 1.5/100,000/year and a high proportion of those patients already taking or intolerant of Aspirin, a large multi-centred trial would be required to fulfil the recruitment for this study. The ability of topical non-steroidal anti-inflammatory drugs to modify COX and prostaglandin expression remains an important but unanswered question. Collaboration with centres in other parts of the world with higher incidences of the disease may be required to ensure adequate recruitment.
ISRCTN: 31503555
The Feasibility of a Cooperatively Owned Large-Scale Hog Farrowing System in North Dakota
Interest in the feasibility of a cooperatively owned large-scale hog farrowing system has been shown by hog producers in North Dakota. The producers realize the problems in securing a continuous supply of disease free feeder pigs of uniform quality during fluctuating price periods. Lack of published data concerning large-scale farrowing systems makes decisions regarding the feasibility and negotiation with lending institutions difficult. The research for this report was conducted under North Dakota Agricultural Experiment Station Projects 1350 and 3337. The research was supported in part by grants from the Business and Industrial Development Department and the Economic Development Administration (Grant Project Number 05-6-01402). Special assistance in conducting the study and preparing the report was provided through the Research and Extension Rural Development Project at North Dakota State University.Agribusiness, Production Economics,
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The economics of health
This report presents results from the Economics of Health project funded by the East Midlands Development Agency. The work was undertaken between November 2007 and February 2008. The main aim of the project was to examine the relationship between mental and physical health and employability, labour market participation and economic performance, with specific attention given to the direction of causal relationships
The temporal dynamic of response inhibition in early childhood: An ERP study of partial and successful inhibition
Event-related potentials were recorded while five-year-old children completed a Go/No-Go task that distinguished between partial inhibition (i.e., response is initiated but cancelled before completion) and successful inhibition (i.e., response is inhibited before it is initiated). Partial inhibition trials were characterized by faster response initiation and later latency of the lateral frontal negativity (LFN) than successful Go and successful inhibition trials. The speed of response initiation was influenced by the response speed on previous trials and influenced the response speed on subsequent trials. Response initiation and action decision dynamically influenced each other, and their temporal interplay determined response inhibition success
Novel thermal management of power electronic devices: high power high frequency planar gunn diodes
Thermal management of next generation of semiconductor devices is becoming more challenging, as the device power
increases and device dimensions decrease. The work is addressing novel thermal measurement and management for
planar heterostructure Gunn diodes, which will be of strategic importance for UK technology and industry
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