255 research outputs found
Polycystic Ovary Syndrome
__Abstract__
The polycystic ovary syndrome (PCOS) was first described in 1935 by Stein and Leventhal
as an association of amenorrhoea, obesity and a typical, polycystically enlarged, appearance
of the ovaries at laparatomy1. Taking into account the absence of advanced imaging
techniques and the relatively high risk that was associated with abdominal surgery
at that time, it is remarkable that this association was noted, and published, as early as
1935. Perhaps this fact alone serves best to demonstrate the wide impact on population
health that is associated with the syndrome that is currently recognised as PCOS. It is
the most frequently occurring endocrinopathy among women of reproductive age, with
an estimated prevalence of 5-10 % among women of fertile age. The ovulatory disorder
that accompanies PCOS is the cause of subfertility and is often the most important
reason for affected women to seek medical care. Furthermore, the clinical phenotype
of PCOS is characterised by signs of elevated levels of free circulating androgens such
as hirsutism, acne and male pattern baldness. However it is important to note that, no
matter what diagnostic criteria are used, PCOS constitutes a notoriously heterogeneous
phenotype. Due to the absence of a robust aetiologic framework for the pathogenesis of
PCOS, physicians are not able to provide a single uniform definition that performs as an
accurate diagnostic tool for the diagnosis of PCOS. Therefore, the diagnosis is still based
on its description as
Mouse Models of Prostate Cancer
The development and optimization of high-throughput screening methods has identified a multitude of genetic changes associated with human disease. The use of immunodeficient and genetically engineered mouse models that mimic the human disease has been crucial in validating the importance of these genetic pathways in prostate cancer. These models provide a platform for finding novel therapies to treat human patients afflicted with prostate cancer as well as those who have debilitating bone metastases. In this paper, we focus on the historical development and phenotypic descriptions of mouse models used to study prostate cancer. We also comment on how closely each model recapitulates human prostate cancer
New constraints on the observable inflaton potential from WMAP and SDSS
We derive some new constraints on single-field inflation from the Wilkinson
Microwave Anisotropy Probe 3-year data combined with the Sloan Luminous Red
Galaxy survey. Our work differs from previous analyses by focusing only on the
observable part of the inflaton potential, or in other words, by making
absolutely no assumption about extrapolation of the potential from its
observable region to its minimum (i.e., about the branch of the potential
responsible for the last ~50 inflationary e-folds). We only assume that
inflation starts at least a few e-folds before the observable Universe leaves
the Hubble radius, and that the inflaton rolls down a monotonic and regular
potential, with no sharp features or phase transitions. We Taylor-expand the
inflaton potential at order v=2, 3 or 4 in the vicinity of the pivot scale,
compute the primordial spectra of scalar and tensor perturbations numerically
and fit the data. For v>2, a large fraction of the allowed models is found to
produce a large negative running of the scalar tilt, and to fall in a region of
parameter space where the second-order slow-roll formalism is strongly
inaccurate. We release a code for the computation of inflationary perturbations
which is compatible with CosmoMC.Comment: 10 pages, 6 figures, codes available at
http://wwwlapp.in2p3.fr/~lesgourgues/inflation/. Version to be published in
Phys.Rev.
Опыт применения криохирургии в гинекологии
Приведены результаты применения низких температур для лечения ряда гинекологических заболеваний и обоснована необходимость широкого внедрения криогенного метода лечения в клиническую практику.The results of low temperature application in treatment of a number of gynecological diseases are presented, the necessity of wide introduction of cryogenic treatment into clinical practice is substantiated
Spherical collapse of dark energy with an arbitrary sound speed
We consider a generic type of dark energy fluid, characterised by a constant
equation of state parameter w and sound speed c_s, and investigate the impact
of dark energy clustering on cosmic structure formation using the spherical
collapse model. Along the way, we also discuss in detail the evolution of dark
energy perturbations in the linear regime. We find that the introduction of a
finite sound speed into the picture necessarily induces a scale-dependence in
the dark energy clustering, which in turn affects the dynamics of the spherical
collapse in a scale-dependent way. As with other, more conventional fluids, we
can define a Jeans scale for the dark energy clustering, and hence a Jeans mass
M_J for the dark matter which feels the effect of dark energy clustering via
gravitational interactions. For bound objects (halos) with masses M >> M_J, the
effect of dark energy clustering is maximal. For those with M << M_J, the dark
energy component is effectively homogeneous, and its role in the formation of
these structures is reduced to its effects on the Hubble expansion rate. To
compute quantitatively the virial density and the linearly extrapolated
threshold density, we use a quasi-linear approach which is expected to be valid
up to around the Jeans mass. We find an interesting dependence of these
quantities on the halo mass M, given some w and c_s. The dependence is the
strongest for masses lying in the vicinity of M ~ M_J. Observing this
M-dependence will be a tell-tale sign that dark energy is dynamic, and a great
leap towards pinning down its clustering properties.Comment: 25 pages, 6 figures, matches version published in JCA
Constraining Inflation
Slow roll reconstruction is derived from the Hamilton-Jacobi formulation of
inflationary dynamics. It automatically includes information from sub-leading
terms in slow roll, and facilitatesthe inclusion of priors based on the
duration on inflation. We show that at low inflationary scales the
Hamilton-Jacobi equations simplify considerably. We provide a new
classification scheme for inflationary models, based solely on the number of
parameters needed to specify the potential, and provide forecasts for likely
bounds on the slow roll parameters from future datasets. A minimal running of
the spectral index, induced solely by the first two slow roll parameters
(\epsilon and \eta) appears to be effectively undetectable by realistic Cosmic
Microwave Background experiments. However, we show that the ability to detect
this signal increases with the lever arm in comoving wavenumber, and we
conjecture that high redshift 21 cm data may allow tests of second order
consistency conditions on inflation. Finally, we point out that the second
order corrections to the spectral index are correlated with the inflationary
scale, and thus the amplitude of the CMB B-mode.Comment: 32 pages. v
Complete solutions to the metric of spherically collapsing dust in an expanding spacetime with a cosmological constant
We present semi-analytical solutions to the background equations describing
the Lema\^itre-Tolman-Bondi (LTB) metric as well as the homogeneous Friedmann
equations, in the presence of dust, curvature and a cosmological constant
Lambda. For none of the presented solutions any numerical integration has to be
performed. All presented solutions are given for expanding and collapsing
phases, preserving continuity in time and radius. Hence, these solutions
describe the complete space time of a collapsing spherical object in an
expanding universe. In the appendix we present for completeness a solution of
the Friedmann equations in the additional presence of radiation, only valid for
the Robertson-Walker metric.Comment: 23 pages, one figure. Numerical module for evaluation of the
solutions released at
http://web.physik.rwth-aachen.de/download/valkenburg/ColLambda/ Matches
published version, published under Open Access. Note change of titl
Serum sex hormone-binding globulin levels are reduced and inversely associated with intrahepatic lipid content and saturated fatty acid fraction in adult patients with glycogen storage disease type 1a
PURPOSE: De novo lipogenesis has been inversely associated with serum sex hormone-binding globulin (SHBG) levels. However, the directionality of this association has remained uncertain. We, therefore, studied individuals with glycogen storage disease type 1a (GSD1a), who are characterized by a genetic defect in glucose-6-phosphatase resulting in increased rates of de novo lipogenesis, to assess the downstream effect on serum SHBG levels. METHODS: A case-control study comparing serum SHBG levels in patients with GSD1a (n = 10) and controls matched for age, sex, and BMI (n = 10). Intrahepatic lipid content and saturated fatty acid fraction were quantified by proton magnetic resonance spectroscopy. RESULTS: Serum SHBG levels were statistically significantly lower in patients with GSD1a compared to the controls (p = 0.041), while intrahepatic lipid content and intrahepatic saturated fatty acid fraction-a marker of de novo lipogenesis-were significantly higher in patients with GSD1a (p = 0.001 and p = 0.019, respectively). In addition, there was a statistically significant, inverse association of intrahepatic lipid content and saturated fatty acid fraction with serum SHBG levels in patients and controls combined (β: - 0.28, 95% CI: - 0.47;- 0.09 and β: - 0.02, 95% CI: - 0.04;- 0.01, respectively). CONCLUSION: Patients with GSD1a, who are characterized by genetically determined higher rates of de novo lipogenesis, have lower serum SHBG levels than controls
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The pseudo McMillan degree of implicit transfer functions of RLC networks
We study the structure of a given RLC network without sources. Since the McMillan degree of the implicit transfer function is not a suitable measure of complexity of the network, we introduce the pseudo McMillan degree to overcome these shortcomings.Using modified nodal analysis models, which are linked directly to the natural network topology, we shaw that the pseudo-McMillan degree equals the sum of the number of capacitors and inductors minus the number of fundamental loops of capacitors and fundamental cutsets of inductors; this is the number of independent dynamic elements in the network. Exploiting this representation we derive a minimal realization of the given RLC network, that is one where the number of independent differential equations equals the pseudo McMillan degree
On the Determination of Neutrino Masses and Dark Energy Evolution from the Cross Correlation of CMB and LSS
We discuss the possibilities of the simultaneous determination of the
neutrino masses and the evolution of dark energy from future cosmological
observations such as cosmic microwave background (CMB), large scale structure
(LSS) and the cross correlation between them. Recently it has been discussed
that there is a degeneracy between the neutrino masses and the equation of
state for dark energy. It is also known that there are some degeneracies among
the parameters describing the dark energy evolutions. We discuss the
implications of these on the cross correlation of CMB with LSS in some details.
Then we consider to what extent we can determine the neutrino masses and the
dark energy evolution using the expected data from CMB, LSS and their cross
correlation.Comment: 18 pages, 8 figure
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