372 research outputs found
High precision spectra at large redshift for dynamical DE cosmologies
The next generation mass probes will investigate DE nature by measuring
non-linear power spectra at various z, and comparing them with high precision
simulations. Producing a complete set of them, taking into account baryon
physics and for any DE state equation w(z), would really be numerically
expensive. Regularities reducing such duty are essential. This paper presents
further n-body tests of a relation we found, linking models with DE state
parameter w(z) to const.-w models, and also tests the relation in hydro
simulations.Comment: PASCOS 2010, the 16th International Symposium on Particles, Strings
and Cosmology, Valencia (Spain), July 19th - 23rd, 201
Impact of gene polymorphisms of gonadotropins and their receptors on human reproductive success
Gonadotropins and their receptors' genes carry several single-nucleotide polymorphisms resulting in endocrine genotypes modulating reproductive parameters, diseases, and lifespan leading to important implications for reproductive success and potential relevance during human evolution. Here we illustrate common genotypes of the gonadotropins and gonadotropin receptors' genes and their clinical implications in phenotypes relevant for reproduction such as ovarian cycle length, age of menopause, testosterone levels, polycystic ovary syndrome, and cancer. We then discuss their possible role in human reproduction and adaptation to the environment. Gonadotropins and their receptors' variants are differently distributed among human populations. Some hints suggest that they may be the result of natural selection that occurred in ancient times, increasing the individual chance of successful mating, pregnancy, and effective post-natal parental cares. The gender-related differences in the regulation of the reproductive endocrine systems imply that many of these genotypes may lead to sex-dependent effects, increasing the chance of mating and reproductive success in one sex at the expenses of the other sex. Also, we suggest that sexual conflicts within the FSH and LH-choriogonadotropin receptor genes contributed to maintain genotypes linked to subfertility among humans. Because the distribution of polymorphic markers results in a defined geographical pattern due to human migrations rather than natural selection, these polymorphisms may have had only a weak impact on reproductive success. On the contrary, such genotypes could acquire relevant consequences in the modern, developed societies in which parenthood attempts often occur at a later age, during a short, suboptimal reproductive window, making clinical fertility treatments necessary
5,5,7,7-Tetrametyl-6,7-dihydro-5H-dibenzo[c,e]azepine
5,5,7,7-Tetrametyl-6,7-dihydro-5H-dibenzo[c,e]azepine has been synthesized as a possible pro-chiral (or tropos) unit for the construction of a chiral catalyst and as a molecular chirality sensor for the absolute configuration assignment by chiroptical spectroscopy. A straightforward synthetic strategy for the preparation of the title compound in high overall yield through sequential addition of the four methyl groups on benzylic positions has been described. A VT-NMR study was used to determine the rotational barrier of the aryl-aryl bond in this biphenylazepine, revealing its torsional flexibility at room temperature, which makes the biphenylazepine suitable as both a chirality probe and a tropos moiety in chiral ligands
Mass-varying neutrino in light of cosmic microwave background and weak lensing
We aim to constrain mass-varying neutrino models using large scale structure
observations and produce forecast for the Euclid survey. We investigate two
models with different scalar field potential and both positive and negative
coupling parameters \beta. These parameters correspond to growing or decreasing
neutrino mass, respectively. We explore couplings up to |\beta|<5. In the case
of the exponential potential, we find an upper limit on <0.004
at 2- level. In the case of the inverse power law potential the null
coupling can be excluded with more than 2-\sigma significance; the limits on
the coupling are \beta>3 for the growing neutrino mass and \beta<-1.5 for the
decreasing mass case. This is a clear sign for a preference of higher
couplings. When including a prior on the present neutrino mass the upper limit
on the coupling becomes |\beta|<3 at 2- level for the exponential
potential. Finally, we present a Fisher forecast using the tomographic weak
lensing from an Euclid-like experiment and we also consider the combination
with the cosmic microwave background (CMB) temperature and polarisation spectra
from a Planck-like mission. If considered alone, lensing data is more efficient
in constraining with respect to CMB data alone. There is, however,
a strong degeneracy in the \beta- plane. When the two data sets
are combined, the latter degeneracy remains, but the errors are reduced by a
factor ~2 for both parameters.Comment: 5 pages, 6 figures. Now published in A&A 500, 657-665 (2009
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