61,701 research outputs found
Growth Patterns in the First Three Years of Life in Children with Classical Congenital Adrenal Hyperplasia Diagnosed by Newborn Screening and Treated with Low Doses of Hydrocortisone
Background: Linear growth is the best clinical parameter for monitoring metabolic control in classical congenital adrenal hyperplasia (CAH). Objective: To analyze growth patterns in children with CAH diagnosed by newborn screening and treated with relatively low doses of hydrocortisone during the first year of life. Patients and Methods: 51 patients (27 females) were diagnosed with classical CAH by newborn screening. All patients were treated with relatively low doses of hydrocortisone (9-15 mg/m(2) body surface area). 47 patients were additionally treated with fludrocortisone. Results: At birth, height SDS (H-SDS) was 1.1 +/- 1 in girls and 0.9 +/- 1.5 in boys. After 3 months, H-SDS decreased to 0.4 +/- 0.9 in girls and to 0.1 +/- 1.3 in boys. Over the 3-year period, H-SDS further decreased to -0.4 +/- 1.8 in girls and to -0.8 +/- 1 in boys and approached the genetic height potential (target H-SDS of girls -0.5 +/- 0.3 and target H-SDS of boys -0.9 +/- 0.7). During the first 9 months of age, growth velocity was slightly decreased in girls (18.2 +/- 1.9 cm) and boys (17.3 +/- 1.6 cm) when compared to a healthy reference population (girls 19.0 +/- 3.9 cm and boys 18.7 +/- 4.7 cm). At the age of 3 years, bone age was appropriate for chronological age in both girls (2.7 +/- 0.5 years) and boys (2.9 +/- 0.5 years). Conclusion: Birth length is above average in children with classical CAH, which might be the result of untreated hyperandrogenism in utero. With relatively low doses of hydrocortisone treatment, growth velocity decreases slightly during the first 9 months and H-SDS then approaches the genetic height potential. Copyright (C) 2010 S. Karger AG, Base
Numerical Relativity Injection Infrastructure
This document describes the new Numerical Relativity (NR) injection
infrastructure in the LIGO Algorithms Library (LAL), which henceforth allows
for the usage of NR waveforms as a discrete waveform approximant in LAL. With
this new interface, NR waveforms provided in the described format can directly
be used as simulated GW signals ("injections") for data analyses, which include
parameter estimation, searches, hardware injections etc. As opposed to the
previous infrastructure, this new interface natively handles sub-dominant modes
and waveforms from numerical simulations of precessing binary black holes,
making them directly accessible to LIGO analyses. To correctly handle
precessing simulations, the new NR injection infrastructure internally
transforms the NR data into the coordinate frame convention used in LAL.Comment: 20 pages, 2 figures, technical repor
Spectral Properties of Magnetic Excitations in Cuprate Two-Leg Ladder Systems
This article summarizes and extends the recent developments in the
microscopic modeling of the magnetic excitations in cuprate two-leg ladder
systems. The microscopic Hamiltonian comprises dominant Heisenberg exchange
terms plus an additional four-spin interaction which is about five times
smaller. We give an overview over the relevant energies like the one-triplon
dispersion, the energies of two-triplon bound states and the positions of
multi-triplon continua and over relevant spectral properties like spectral
weights and spectral densities in the parameter regime appropriate for cuprate
systems. It is concluded that an almost complete understanding of the magnetic
excitations in undoped cuprate ladders has been obtained as measured by
inelastic neutron scattering, inelastic light (Raman) scattering and infrared
absorption.Comment: 26 pages, 10 figures, review for Mod. Phys. Lett.
On the Electronic Spectroscopy of Closed Shell Cations Derived From Resonance Stabilized Radicals: Insights From Theory and Franck-Condon Analysis
Context. Recent attention has been directed on closed-shell aromatic cations as potential carriers of the diffuse interstellar bands. The spectra of mass-selected, matrix-isolated benzylium, and tropylium cations were recently reported. The visible spectrum of benzylium exhibits a large Franck-Condon (FC) envelope, inconsistent with diffuse interstellar band carriers.
Aims. We perform a computational analysis of the experimentally studied benzylium spectrum before extending the methods to a range of larger, closed-shell aromatic cations to determine the potential for this class of systems as diffuse interstellar band carriers.
Methods. Density functional theory (DFT), time-dependant ((TD)DFT), and multi-configurational self-consistent field second-order perturbation theory (MRPT2) methods in concert with multidimensional FC analysis is used to model the benzylium spectrum. These methods are extended to larger closed-shell aromatic hydrocarbon cations derived from resonance-stabilized radicals, which are predicted to show strong S0 → Sn transitions in the visible region. The ionization energies of a range of these systems are also calculated by DFT.
Results. The simulated benzylium spectrum was found to yield excellent agreement with the experimental spectrum showing an extended progression in a low frequency (510 cm-1) ring distortion mode. The FC progression was found to be significantly quenched in the larger species: 1-indanylium, 1-naphthylmethylium, and fluorenium. Excitation and ionization energies of the closed-shell cations were found to be consistent with diffuse interstellar band carriers, with the former lying in the visible range and the latter straddling the Lyman limit in the 13−14 eV range.
Conclusions. Large closed-shell polycyclic aromatic hydrocarbon cations remain viable candidate carriers of the diffuse interstellar bands
Probing fractal magnetic domains on multiple length scales in Nd2Fe14B
Using small-angle neutron scattering, we demonstrate that the complex
magnetic domain patterns at the surface of Nd2Fe14B, revealed by quantitative
Kerr and Faraday microscopy, propagate into the bulk and exhibit structural
features with dimensions down to 6 nm, the domain wall thickness. The observed
fractal nature of the domain structures provides an explanation for the
anomalous increase in the bulk magnetization of Nd2Fe14B below the
spin-reorientation transition. These measurements open up a rich playground for
studies of fractal structures in highly anisotropic magnetic systems.Comment: Accepted for publication in Phys. Rev. Lett. (4 pages, 4 figures
Detection of electrical spin injection by light-emitting diodes in top- and side-emission configuration
Detection of the degree of circular polarization of the electroluminescence
of a light-emitting diode fitted with a spin injecting contact (a spin-LED)
allows for a direct determination of the spin polarization of the injected
carriers. Here, we compare the detection efficiency of (Al,Ga)As spin-LEDs
fitted with a (Zn,Be,Mn)Se spin injector in top- and side-emission
configuration. In contrast with top emission, we cannot detect the electrical
spin injection in side emission from analysing the degree of circular
polarization of the electroluminescence. To reduce resonant optical pumping of
quantum-well excitons in the side emission, we have analysed structures with
mesa sizes as small as 1 micron.Comment: 15 pages with 3 figure
Recent developments in classical density functional theory: Internal energy functional and diagrammatic structure of fundamental measure theory
An overview of several recent developments in density functional theory for
classical inhomogeneous liquids is given. We show how Levy's constrained search
method can be used to derive the variational principle that underlies density
functional theory. An advantage of the method is that the Helmholtz free energy
as a functional of a trial one-body density is given as an explicit expression,
without reference to an external potential as is the case in the standard
Mermin-Evans proof by reductio ad absurdum. We show how to generalize the
approach in order to express the internal energy as a functional of the
one-body density distribution and of the local entropy distribution. Here the
local chemical potential and the bulk temperature play the role of Lagrange
multipliers in the Euler-Lagrange equations for minimiziation of the
functional. As an explicit approximation for the free-energy functional for
hard sphere mixtures, the diagrammatic structure of Rosenfeld's fundamental
measure density unctional is laid out. Recent extensions, based on the
Kierlik-Rosinberg scalar weight functions, to binary and ternary non-additive
hard sphere mixtures are described.Comment: 15 pages, 6 figure
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