26,420 research outputs found
Bone mineral content after renal transplantation
Forearm bone mineral content (BMC), as evaluated by photonabsorption densitometry, was measured in 28 cadaver kidney donor recipients who entered the study 8 weeks postoperatively and were followed up for 18 months. BMC decreased signifiantly (p<0.05) but marginally in placebo-treated patients (n=14) (initial BMC 1.09±0.25 g/cm; final BMC 1.05±0.24). Fourteen patients were prophylactically given 1,25(OH)2vitamin D3 in a dose which avoided hypercalcemia and hypercalciuria (sim0.25 µg/day); under 1,25(OH)2 vitamin D3 prophylaxis a significant decrease of forearm BMC was observed no longer (initial BMC 0.94±0.21 g/cm; final BMC 0.95±0.21), but the difference between placebo and 1,25(OH)2 vitamin D3 narrowly missed statistical significance (p=0.066).
It is concluded that the decrease of forearm BMC is negligible in transplant recipients with low steroid regimens. The data suggest a trend for prophylaxis with 1,25(OH)2 vitamin D3 to slightly ameliorate forearm (cortical) BMC loss
Ohio Agribusiness Compensation Study: 1986
Exact date of working paper unknown.Information about competitive wage and compensation packages is important to attracting and maintaining a productive workforce. A 1986 survey of compensation practices of Ohio Agribusiness firms revealed that bonuses and profit-sharing plans play a more important role in determining pay level than they did in 1982. Larger firms, measured by gross annual sales, still pay more than smaller firms; but trends by geographic location are not as distinct as they were in 1982. Non-managerial agribusiness employees still earn less than their metropolitan counterparts, but the gap is decreasing
Single top production in a non-minimal supersymmetric model
We study single top production at the LHC in a SUSY-QCD model with a heavy
Dirac gluino. The presence of a heavy Dirac gluino allows for notable top-up
flavour changing neutral currents. In this scenario, we find that the process
ug->tg gives the largest contribution to single top production via FCNCs at the
LHC. The key features of this signal are that the top quark is produced very
forward and that it is asymmetric to its anti-top counterpart, as the latter
lacks a valence quark.Comment: 9 pages, 4 figures, a background added, references added, minor
revisions, to be published in Phys. Lett.
Multi-excitonic complexes in single InGaN quantum dots
Cathodoluminescence spectra employing a shadow mask technique of InGaN layers
grown by metal organic chemical vapor deposition on Si(111) substrates are
reported. Sharp lines originating from InGaN quantum dots are observed.
Temperature dependent measurements reveal thermally induced carrier
redistribution between the quantum dots. Spectral diffusion is observed and was
used as a tool to correlate up to three lines that originate from the same
quantum dot. Variation of excitation density leads to identification of exciton
and biexciton. Binding and anti-binding complexes are discovered.Comment: 3 pages, 4 figure
Marine bivalve geochemistry and shell ultrastructure from modern low pH environments
Abstract. Bivalve shells can provide excellent archives of past environmental change but have not been used to interpret ocean acidification events. We investigated carbon, oxygen and trace element records from different shell layers in the mussels Mytilus galloprovincialis (from the Mediterranean) and M. edulis (from the Wadden Sea) combined with detailed investigations of the shell ultrastructure. Mussels from the harbour of Ischia (Mediterranean, Italy) were transplanted and grown in water with mean pHT 7.3 and mean pHT 8.1 near CO2 vents on the east coast of the island of Ischia. The shells of transplanted mussels were compared with M. edulis collected at pH ~8.2 from Sylt (German Wadden Sea). Most prominently, the shells recorded the shock of transplantation, both in their shell ultrastructure, textural and geochemical record. Shell calcite, precipitated subsequently under acidified seawater responded to the pH gradient by an in part disturbed ultrastructure. Geochemical data from all test sites show a strong metabolic effect that exceeds the influence of the low-pH environment. These field experiments showed that care is needed when interpreting potential ocean acidification signals because various parameters affect shell chemistry and ultrastructure. Besides metabolic processes, seawater pH, factors such as salinity, water temperature, food availability and population density all affect the biogenic carbonate shell archive.</jats:p
Determination of Strong-Interaction Widths and Shifts of Pionic X-Rays with a Crystal Spectrometer
Pionic 3d-2p atomic transitions in F, Na, and Mg have been studied using a bent crystal spectrometer. The pionic atoms were formed in the production target placed in the external proton beam of the Space Radiation Effects Laboratory synchrocyclotron. The observed energies and widths of the transitions are E=41679(3) eV and Γ=21(8) eV, E=62434(18) eV and Γ=22(80) eV, E=74389(9) eV and Γ=67(35) eV, in F, Na, and Mg, respectively. The results are compared with calculations based on a pion-nucleus optical potential
Fast Evaluation of Feynman Diagrams
We develop a new representation for the integrals associated with Feynman
diagrams. This leads directly to a novel method for the numerical evaluation of
these integrals, which avoids the use of Monte Carlo techniques. Our approach
is based on based on the theory of generalized sinc () functions,
from which we derive an approximation to the propagator that is expressed as an
infinite sum. When the propagators in the Feynman integrals are replaced with
the approximate form all integrals over internal momenta and vertices are
converted into Gaussians, which can be evaluated analytically. Performing the
Gaussians yields a multi-dimensional infinite sum which approximates the
corresponding Feynman integral. The difference between the exact result and
this approximation is set by an adjustable parameter, and can be made
arbitrarily small. We discuss the extraction of regularization independent
quantities and demonstrate, both in theory and practice, that these sums can be
evaluated quickly, even for third or fourth order diagrams. Lastly, we survey
strategies for numerically evaluating the multi-dimensional sums. We illustrate
the method with specific examples, including the the second order sunset
diagram from quartic scalar field theory, and several higher-order diagrams. In
this initial paper we focus upon scalar field theories in Euclidean spacetime,
but expect that this approach can be generalized to fields with spin.Comment: uses feynmp macros; v2 contains improved description of
renormalization, plus other minor change
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