78 research outputs found
Ontogeny and pharmacogenetics: determinants of age-associated differences in drug clearance during human development
Development per se represents a continuum of biologic events that enable adaptation,
somatic growth and eventually, reproduction. From a societal, psychosocial, behavioral
and medical perspective, it is generally appreciated that infants and children are far
different from adults and elderly. As well, pediatric patients suffer from conditions and
diseases that in many instances are unique and have no true counterpart in adults. These
particular differences are generally known and to a great degree, determine how infants,
children and adolescents are provided for both within the context of medical care and in
society. What remains often under-appreciated is the
Dark Matter And With Minimal Soft SUSY Breaking
CMSSM boundary conditions are usually used when calculating cosmological dark
matter densities. In this paper we calculate the cosmological density of dark
matter in the MSSM using minimal soft SUSY breaking boundary
conditions. These boundary conditions incorporate several attractive features:
they are consistent with Yukawa unification, they result in a
"natural" inverted scalar mass hierarchy and they reduce the dimension 5
operator contribution to the proton decay rate. With regards to dark matter, on
the other hand, this is to a large extent an unexplored territory with large
squark and slepton masses , large and small . We find that in most regions of parameter space the cosmological density of
dark matter is considerably less than required by the data. However there is a
well--defined, narrow region of parameter space which provides the observed
relic density of dark matter, as well as a good fit to precision electroweak
data, including top, bottom and tau masses, and acceptable bounds on the
branching fraction of . We present predictions for Higgs
and SUSY spectra, the dark matter detection cross section and the branching
ratio in this region of parameter space.Comment: 15 pages, 5 figure
The influence of geochemical variation among Globigerinoides ruber individuals on paleoceanographic reconstructions
Variation among individuals within species is a biological precondition for co-existence. Traditional geochemical analysis based on bulk averages from multiple planktic foraminifera individuals facilitates rapid data gathering but necessarily means the loss of large amounts of potentially crucial information into variability within a given sample. As the sensitivity of geochemical analysis improves, it is now feasible to build sufficiently powerful datasets to investigate paleoclimatic variation at the level of individual specimens. Here, we investigate geochemical and morphological variation among the sensu stricto, sensu lato and sensu lato extreme subspecies of the workhorse extant planktic foraminifera Globigerinoides ruber. Our experimental design distinguishes between subspecies and intraspecific variability as well as the repeatability of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). We show that geochemical variability in Mg/Ca ratios is driven by differences in subspecies depth habitat and that ontogenetic trends in Mg/Ca ratios are evident in the final whorl, with the final chamber consistently showing depleted Mg/Ca. These ontogenetic trends are not driven by individual chamber or test size. The Mg/Ca value variance among individuals is ~100 times higher than the variance among repeated laser spot analyses of a signal chambers, directing laboratory protocols towards the need to sample ecologically and environmentally homogeneous samples. Our results emphasize that we can use LA-ICP-MS to quantify how individual variability aggregates to bulk results, and highlights that, with sufficient sample sizes, it is possible to reveal how intraspecific variability alters geochemical inference
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