5,417 research outputs found
Early introduction of fish decreases the risk of eczema in infants
BACKGROUND: Atopic eczema in infants has increased in western societies. Environmental factors and the introduction of food may affect the risk of eczema. AIMS: To investigate the prevalence of eczema among infants in western Sweden, describe patterns of food introduction and assess risk factors for eczema at 1 year of age. METHODS: Data were obtained from a prospective, longitudinal cohort study of infants born in western Sweden in 2003; 8176 families were randomly selected and, 6 months after the infant\u27s birth, were invited to participate and received questionnaires. A second questionnaire was sent out when the infants were 12 months old. Both questionnaires were completed and medical birth register data were obtained for 4921 infants (60.2% of the selected population). RESULTS: At 1 year of age, 20.9% of the infants had previous or current eczema. Median age at onset was 4 months. In multivariable analysis, familial occurrence of eczema, especially in siblings (OR 1.87; 95% confidence interval (CI) 1.50 to 2.33) or the mother (OR 1.54; 95% CI 1.30 to 1.84), remained an independent risk factor. Introducing fish before 9 months of age (OR 0.76; 95% CI 0.62 to 0.94) and having a bird in the home (OR 0.35; 95% CI 0.17 to 0.75) were beneficial. CONCLUSIONS: One in five infants suffer from eczema during the first year of life. Familial eczema increased the risk, while early fish introduction and bird keeping decreased it. Breast feeding and time of milk and egg introduction did not affect the risk
Wong-Zakai approximation of solutions to reflecting stochastic differential equations on domains in Euclidean spaces II
The strong convergence of Wong-Zakai approximations of the solution to the
reflecting stochastic differential equations was studied in [2]. We continue
the study and prove the strong convergence under weaker assumptions on the
domain.Comment: To appear in "Stochastic Analysis and Applications 2014-In Honour of
Terry Lyons", Springer Proceedings in Mathematics and Statistic
Analysis of Short Tandem Repeats by Parallel DNA Threading
The majority of studies employing short tandem repeats (STRs) require investigation of several of these genetic markers. As such, we demonstrate the feasibility of the trinucleotide threading (TnT) approach for scalable analysis of STRs. The TnT method represents a parallel amplification alternative that addresses the obstacles associated with multiplex PCR. In this study, analysis of the STR fragments was performed with capillary gel electrophoresis; however, it should be possible to combine our approach with the massive 454 sequencing platform to considerably increase the number of targeted STRs
Generation of Large-Scale Vorticity in a Homogeneous Turbulence with a Mean Velocity Shear
An effect of a mean velocity shear on a turbulence and on the effective force
which is determined by the gradient of Reynolds stresses is studied. Generation
of a mean vorticity in a homogeneous incompressible turbulent flow with an
imposed mean velocity shear due to an excitation of a large-scale instability
is found. The instability is caused by a combined effect of the large-scale
shear motions (''skew-induced" deflection of equilibrium mean vorticity) and
''Reynolds stress-induced" generation of perturbations of mean vorticity.
Spatial characteristics, such as the minimum size of the growing perturbations
and the size of perturbations with the maximum growth rate, are determined.
This instability and the dynamics of the mean vorticity are associated with the
Prandtl's turbulent secondary flows. This instability is similar to the
mean-field magnetic dynamo instability. Astrophysical applications of the
obtained results are discussed.Comment: 8 pages, 3 figures, REVTEX4, submitted to Phys. Rev.
Luminescence from highly excited nanorings: Luttinger liquid description
We study theoretically the luminescence from quantum dots of a ring geometry.
For high excitation intensities, photoexcited electrons and holes form Fermi
seas. Close to the emission threshold, the single-particle spectral lines
aquire weak many-body satellites. However, away from the threshold, the
discrete luminescence spectrum is completely dominated by many-body
transitions. We employ the Luttinger liquid approach to exactly calculate the
intensities of all many-body spectral lines. We find that the transition from
single-particle to many-body structure of the emission spectrum is governed by
a single parameter and that the distribution of peaks away from the threshold
is universal.Comment: 10 pages including 2 figure
The event generator DECAY4 for simulation of double beta processes and decay of radioactive nuclei
The computer code DECAY4 is developed to generate initial energy, time and
angular distributions of particles emitted in radioactive decays of nuclides
and nuclear (atomic) deexcitations. Data for description of nuclear and atomic
decay schemes are taken from the ENSDF and EADL database libraries. The
examples of use of the DECAY4 code in several underground experiments are
described.Comment: 8 pages, 1 fi
Interaction of eukaryotic translation initiation factor 4G with the nuclear cap-binding complex provides a link between nuclear and cytoplasmic functions of the m7 guanosine cap
In eukaryotes the majority of mRNAs have an m7G cap that is added cotranscriptionally and that plays an important role in many aspects of mRNA metabolism. The nuclear cap-binding complex (CBC; consisting of CBP20 and CBP80) mediates the stimulatory functions of the cap in pre-mRNA splicing, 3' end formation, and U snRNA export. As little is known about how nuclear CBC mediates the effects of the cap in higher eukaryotes, we have characterized proteins that interact with CBC in HeLa cell nuclear extracts as potential mediators of its function. Using cross-linking and coimmunoprecipitation, we show that eukaryotic translation initiation factor 4G (eIF4G), in addition to its function in the cytoplasm, is a nuclear CBC-interacting protein. We demonstrate that eIF4G interacts with CBC in vitro and that, in addition to its cytoplasmic localization, there is a significant nuclear pool of eIF4G in mammalian cells in vivo. Immunoprecipitation experiments suggest that, in contrast to the cytoplasmic pool, much of the nuclear eIF4G is not associated with eIF4E (translation cap binding protein of eIF4F) but is associated with CBC. While eIF4G stably associates with spliceosomes in vitro and shows close association with spliceosomal snRNPs and splicing factors in vivo, depletion studies show that it does not participate directly in the splicing reaction. Taken together the data indicate that nuclear eIF4G may be recruited to pre-mRNAs via its interaction with CBC and accompanies the mRNA to the cytoplasm, facilitating the switching of CBC for eIF4F. This may provide a mechanism to couple nuclear and cytoplasmic functions of the mRNA cap structure
Collision Dynamics and Solvation of Water Molecules in a Liquid Methanol Film
Environmental molecular beam experiments are used to examine water
interactions with liquid methanol films at temperatures from 170 K to 190 K. We
find that water molecules with 0.32 eV incident kinetic energy are efficiently
trapped by the liquid methanol. The scattering process is characterized by an
efficient loss of energy to surface modes with a minor component of the
incident beam that is inelastically scattered. Thermal desorption of water
molecules has a well characterized Arrhenius form with an activation energy of
0.47{\pm}0.11 eV and pre-exponential factor of 4.6 {\times} 10^(15{\pm}3)
s^(-1). We also observe a temperature dependent incorporation of incident water
into the methanol layer. The implication for fundamental studies and
environmental applications is that even an alcohol as simple as methanol can
exhibit complex and temperature dependent surfactant behavior.Comment: 8 pages, 5 figure
Uncertainty quantification for kinetic models in socio-economic and life sciences
Kinetic equations play a major rule in modeling large systems of interacting
particles. Recently the legacy of classical kinetic theory found novel
applications in socio-economic and life sciences, where processes characterized
by large groups of agents exhibit spontaneous emergence of social structures.
Well-known examples are the formation of clusters in opinion dynamics, the
appearance of inequalities in wealth distributions, flocking and milling
behaviors in swarming models, synchronization phenomena in biological systems
and lane formation in pedestrian traffic. The construction of kinetic models
describing the above processes, however, has to face the difficulty of the lack
of fundamental principles since physical forces are replaced by empirical
social forces. These empirical forces are typically constructed with the aim to
reproduce qualitatively the observed system behaviors, like the emergence of
social structures, and are at best known in terms of statistical information of
the modeling parameters. For this reason the presence of random inputs
characterizing the parameters uncertainty should be considered as an essential
feature in the modeling process. In this survey we introduce several examples
of such kinetic models, that are mathematically described by nonlinear Vlasov
and Fokker--Planck equations, and present different numerical approaches for
uncertainty quantification which preserve the main features of the kinetic
solution.Comment: To appear in "Uncertainty Quantification for Hyperbolic and Kinetic
Equations
Cooling dynamics of carbon cluster anions
A series of ion storage experiments on small carbon cluster anions was conducted to understand size-dependent cooling processes. The laser-induced delayed electron detachment time profile show clear even/odd alternation due to the presence of the electronic cooling. The time evolution of the internal energy distribution was simulated for Cn- (n=4 to 7) with a common procedure taking vibrational and electronic cooling into account
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