2,596 research outputs found
Cosmetic Surgery and the Practice of Medicine
In this post-modern world, there is a recognisable bent in the media to promote the idea of youth (read as synonymous with beauty and power) to the fullest. The result is that public perceptions of the normal bodily processes of aging are viewed as detrimental or unattractive. Since we are “social creatures”, as Aristotle put it, the mediasation, for example, in magazines, TV, film, fashion, music, etc. of youth as ideal is bound to impact upon our individual ideas of ‘what-is-good-for-me'. Since youth is viewed by society as a good, it is possible to understand an individual's desire to take advantage, when it is possible, of the cosmetic procedures that fortify this ideal. Moreover, since medical practitioners are part of the public, and no more or less swayed by such ideologies, it is also reasonable to assume that some will advantage themselves and take up the gauntlet of promoting youth, although perhaps in the more medical guise of ‘remedying the ills of aging' in other words, enter the practice of cosmetic surgery.
South African Family Practice Vol. 50 (1) 2008: pp. 50-5
Simulation and experimental verification of W-band finite frequency selective surfaces on infinite background with 3D full wave solver NSPWMLFMA
We present the design, processing and testing of a W-band finite by infinite and a finite by finite Grounded Frequency Selective Surfaces (FSSs) on infinite background. The 3D full wave solver Nondirective Stable Plane Wave Multilevel Fast Multipole Algorithm (NSPWMLFMA) is used to simulate the FSSs. As NSPWMLFMA solver improves the complexity matrix-vector product in an iterative solver from O(N(2)) to O(N log N) which enables the solver to simulate finite arrays with faster execution time and manageable memory requirements. The simulation results were verified by comparing them with the experimental results. The comparisons demonstrate the accuracy of the NSPWMLFMA solver. We fabricated the corresponding FSS arrays on quartz substrate with photolithographic etching techniques and characterized the vector S-parameters with a free space Millimeter Wave Vector Network Analyzer (MVNA)
Quality of herbage at different latitudes.
In a cooperative experiment, yield and herbage quality of timothy was measured during the uninterrupted growth of the 1st cut at 6 lat. (51-69 deg N). Rate of production was greatest at Tromso (69 deg N), apparently because of the long day and rapid reproductive development. Digestibility of OM declined faster at higher lat. because stem development proceeded faster and less leaf DM was produced. At the same morphological stage, digestibility of the whole crop was better at higher lat. because of the better digestibility of the cell walls from the stems. It was concluded that rate of lignification could not keep pace with the rapid rate of stem development. (Abstract retrieved from CAB Abstracts by CABI’s permission
Low energy measurement of the 7Be(p,gamma)8B cross section
We have measured the cross section of the 7Be(p,gamma)8B reaction for E_cm =
185.8 keV, 134.7 keV and 111.7 keV using a radioactive 7Be target (132 mCi).
Single and coincidence spectra of beta^+ and alpha particles from 8B and 8Be^*
decay, respectively, were measured using a large acceptance spectrometer. The
zero energy S factor inferred from these data is 18.5 +/- 2.4 eV b and a
weighted mean value of 18.8 +/- 1.7 eV b (theoretical uncertainty included) is
deduced when combining this value with our previous results at higher energies.Comment: Accepted for publication in Phys. Rev. Let
Comparison of low--energy resonances in 15N(alpha,gamma)19F and 15O(alpha,gamma)19Ne and related uncertainties
A disagreement between two determinations of Gamma_alpha of the astro-
physically relevant level at E_x=4.378 MeV in 19F has been stated in two recent
papers by Wilmes et al. and de Oliveira et al. In this work the uncertainties
of both papers are discussed in detail, and we adopt the value
Gamma_alpha=(1.5^{+1.5}_{-0.8})10^-9eV for the 4.378 MeV state. In addition,
the validity and the uncertainties of the usual approximations for mirror
nuclei Gamma_gamma(19F) approx Gamma_gamma(19Ne), theta^2_alpha(19F) approx
theta^2_alpha(19Ne) are discussed, together with the resulting uncertainties on
the resonance strengths in 19Ne and on the 15O(alpha,gamma)19Ne rate.Comment: 9 pages, Latex, To appear in Phys. Rev.
Means and covariance functions for geostatistical compositional data: an axiomatic approach
This work focuses on the characterization of the central tendency of a sample
of compositional data. It provides new results about theoretical properties of
means and covariance functions for compositional data, with an axiomatic
perspective. Original results that shed new light on the geostatistical
modeling of compositional data are presented. As a first result, it is shown
that the weighted arithmetic mean is the only central tendency characteristic
satisfying a small set of axioms, namely continuity, reflexivity and marginal
stability. Moreover, this set of axioms also implies that the weights must be
identical for all parts of the composition. This result has deep consequences
on the spatial multivariate covariance modeling of compositional data. In a
geostatistical setting, it is shown as a second result that the proportional
model of covariance functions (i.e., the product of a covariance matrix and a
single correlation function) is the only model that provides identical kriging
weights for all components of the compositional data. As a consequence of these
two results, the proportional model of covariance function is the only
covariance model compatible with reflexivity and marginal stability
Solar Fusion Cross Sections
We review and analyze the available information for nuclear fusion cross
sections that are most important for solar energy generation and solar neutrino
production. We provide best values for the low-energy cross-section factors
and, wherever possible, estimates of the uncertainties. We also describe the
most important experiments and calculations that are required in order to
improve our knowledge of solar fusion rates.Comment: LaTeX file, 48 pages (figures not included). To appear in Rev. Mod.
Phys., 10/98. All authors now listed. Full postscript version with figures
available at http://www.sns.ias.edu/~jnb/Papers/Preprints/nuclearfusion.htm
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