1,999 research outputs found
Metabolomics application in maternal-fetal medicine
Metabolomics in maternal-fetal medicine is still an "embryonic" science. However, there is already an increasing interest in metabolome of normal and complicated pregnancies, and neonatal outcomes. Tissues used for metabolomics interrogations of pregnant women, fetuses and newborns are amniotic fluid, blood, plasma, cord blood, placenta, urine, and vaginal secretions. All published papers highlight the strong correlation between biomarkers found in these tissues and fetal malformations, preterm delivery, premature rupture of membranes, gestational diabetes mellitus, preeclampsia, neonatal asphyxia, and hypoxic-ischemic encephalopathy. The aim of this review is to summarize and comment on original data available in relevant published works in order to emphasize the clinical potential of metabolomics in obstetrics in the immediate future
Non-linear water waves generated by impulsive motion of submerged obstacles
A fully non-linear problem on unsteady water waves generated by an
impulsively moving obstacle is studied analytically. Our method involves
reduction of the Euler equations to the integral-differential system for the
wave elevation together with normal and tangential fluid velocities at a free
surface. Exact model equations are derived in explicit form in a case where
an isolated obstacle is presented by a totally submerged elliptic cylinder. A
small-time asymptotic solution is constructed for a cylinder which starts
with constant acceleration from rest. It is demonstrated that the
leading-order solution terms describe several wave regimes such as the
formation of non-stationary splash jets by vertical rising or vertical
submersion of the obstacle; the generation of diverging waves is also
observed
Bounce Loop Quantum Cosmology Corrected Gauss-Bonnet Gravity
We develop a Gauss-Bonnet extension of Loop Quantum Cosmology, by introducing
holonomy corrections in modified theories of gravity. Within
the context of our formalism, we provide a perturbative expansion in the
critical density, a parameter characteristic of Loop Quantum Gravity theories,
and we result in having leading order corrections to the classical
theories of gravity. After extensively discussing the
formalism, we present a reconstruction method that makes possible to find the
Loop Quantum Cosmology corrected theory that can realize
various cosmological scenarios. Specifically, we studied exponential and
power-law bouncing cosmologies, emphasizing on the behavior near the bouncing
point and in some cases, the behavior for all the values of the cosmic time is
obtained. We exemplify our theoretical constructions by using bouncing
cosmologies, and we investigate which Loop Quantum Cosmology corrected
Gauss-Bonnet modified gravities can successfully realize such cosmologies.Comment: Revised version, to appear in PR
Measuring the Luminosity of a gamma gamma Collider with gamma gamma -> l+ l- gamma Events
The process gamma gamma -> l+ l- is highly suppressed when the total angular
momentum of the two colliding photons is zero so that it cannot be used for
luminosity determination. This configuration, however is needed for Higgs
production at a photon collider. It will be shown that the process gamma gamma
-> l+ l- gamma can be used in this case to measure the luminosity of a collider
with a precision that is good enough not to limit the error on the partial
decay width Gamma(H -> gamma gamma).Comment: Final version, accepted by journa
Internal waves in marginally stable abyssal stratified flows
The problem on internal waves in a weakly stratified two-layer fluid is
studied semi-analytically. We discuss the 2.5-layer fluid flows with
exponential stratification of both layers. The long-wave model describing
travelling waves is constructed by means of a scaling procedure with a small
Boussinesq parameter. It is demonstrated that solitary-wave regimes can be
affected by the Kelvin–Helmholtz instability arising due to interfacial
velocity shear in upstream flow.</p
Rapid convergence of time-averaged frequency in phase synchronized systems
Numerical and experimental evidence is presented to show that many phase
synchronized systems of non-identical chaotic oscillators, where the chaotic
state is reached through a period-doubling cascade, show rapid convergence of
the time-averaged frequency. The speed of convergence toward the natural
frequency scales as the inverse of the measurement period. The results also
suggest an explanation for why such chaotic oscillators can be phase
synchronized.Comment: 6 pages, 9 figure
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