22,582 research outputs found
Contributions of Vacuum and Plasmon Modes to the Force on a Small Sphere near a Plate
The force on a small sphere with a plasma model dielectric function and in
the presence of a perfectly reflecting plane is considered. The contribution of
both the vacuum modes of the quantized electromagnetic field and of plasmon
modes in the sphere are discussed. In the case that the plasmon modes are in
their ground state, quasi-oscillatory terms from the vacuum and plasmon parts
cancel one another, leading a monotonic attractive force. If the plasmon modes
are not in the ground state, the net force is quasi-oscillatory. In both cases,
the sphere behaves in the same way as does an atom in either its ground state
or an excited state.Comment: 7 pages, no figures, talk presented at "Quantum Fields under External
Conditions - 2005", Barcelona, Spain, September 200
Relative Abundance, Seasonal Distribution and Taxonomy of Sphingidae of Northeast Arkansas
A total of 38 species of sphingids, with keys and descriptions, are reported from Northeast Arkansas. Graphs and tables are presented to show relative abundance and seasonal distribution. Drawings of genitalia, fore tibiae, and forewings, as well as photographs of species in the key are included
Solutions to the 1d Klein-Gordon equation with cutoff Coulomb potentials
In a recent paper by Barton (J. Phys. A40, 1011 (2007)), the 1-dimensional
Klein-Gordon equation was solved analytically for the non-singular Coulomb-like
potential V_1(|x|) = -\alpha/(|x|+a). In the present paper, these results are
completely confirmed by a numerical formulation that also allows a solution for
an alternative cutoff Coulomb potential V_2(|x|) = -\alpha/|x|, ~|x| > a, and
otherwise V_2(|x|) = -\alpha/a.Comment: 8 pages, 4 figure
Time to address the double inequality of differences in dietary intake between Scotland and England
Geographical disparities in health outcomes have been evident across the UK for decades. There is limited recent analysis on the dietary differences between Scotland and England that might go some way to explain these health differences. This study aimed to assess whether, and to what degree, aspects of diet and nutrition differ between Scottish and English populations, specifically between those with similar household incomes. Twelve years of UK food purchase data (2001-2012) were pooled and used to estimate household level consumption data for Scotland and England. Population mean food consumption and nutrient intakes were estimated, adjusting for known confounders (year, age of household reference person, age they left full-time education and income). Comparison was also made within equivalised income quintiles. Analysis showed that the foods and nutrients that should be increased in the diet (highlighted in the Scottish Dietary Goals) were lower in Scotland than England (e.g. fruit and vegetables 267g/day (99%CI 259-274g/day) vs. 298g/day (99%CI 296-301g/day), P<0.001). Likewise, foods and drinks linked with poor health outcomes were higher in Scotland. These regional inequalities in diet were even more pronounced in the lower income groups (e.g. red and processed meat consumption in the lowest income quintile was 65g/day (99% CI 61-69g/day) in Scotland vs. 58g/day (99% CI 57-60g/day) in England, P<0.001, but similar in the highest income quintile (58g/day (99%CI 54-61 g/day) vs. 59g/day (99% CI 58-60 g/day) respectively). A poorer diet in Scotland compared to England, particularly among disadvantaged groups, may contribute to differences in excess mortality between countries
Research into alternative network approaches for space operations
The main goal is to resolve the interoperability problem of applications employing DOD TCP/IP (Department of Defence Transmission Control Protocol/Internet Protocol) family of protocols on a CCITT/ISO based network. The objective is to allow them to communicate over the CCITT/ISO protocol GPLAN (General Purpose Local Area Network) network without modification to the user's application programs. There were two primary assumptions associated with the solution that was actually realized. The first is that the solution had to allow for future movement to the exclusive use of the CCITT/ISO standards. The second is that the solution had to be software transparent to the currently installed TCP/IP and CCITT/ISO user application programs
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