80,039 research outputs found
Paediatric wheezy admissions at and around school holiday periods
Objective: To study the influence of school holidays on paediatric admissions with wheezing. Design, setting and patients: Retrospective analysis of all admissions due to wheeze in the paediatric age group. Regional hospital catering for all such admissions, subdivided by age group. Outcome measures: Comparison of hospitalisations due to wheezing before, during and after school holiday periods. Results: Summated admissions showed an increase in admissions over the Christmas period for preschool children, and a decrease for school age children. In Easter and at the start of the summer holidays, admissions decreased in all age groups, except for the late school age group which showed increased admissions in April-May. After the summer holidays, a rise in admissions was noted for all ages. Conclusions: Our findings support the multiphenotypic theory for the precipitation of wheezy attacks, with a changeover from a predominantly viral respiratory trigger to a more atopic form of the disease at around 10 years of age. Prophylaxis during school periods is especially important, and advice leading to prophylaxis dose reduction in the benign summer months should be accompanied by advice to restart adequate prophylaxis medication prior to restarting school.peer-reviewe
GEODYN operations description, volume 3
The operating and set-up procedures for the multi-satellite, multi-arc GEODYN- Orbit Determination program are described. All system output is analyzed. The GEODYN Program is the nucleus of the entire GEODYN system. It is a definitive orbit and geodetic parameter estimation program capable of simultaneously processing observations from multiple arcs of multiple satellites. GEODYN has two modes of operation: (1) the data reduction mode and (2) the orbit generation mode
On the evidence for brown-dwarf secondary stars in cataclysmic variables
We present the K-band spectrum of the cataclysmic variable LL And, obtained
using NIRSPEC on Keck-II. The spectrum shows no evidence for the absorption
features observed by Howell & Ciardi (2001), which these authors used to claim
a detection of a brown-dwarf secondary star in LL And. In light of our new
data, we review the evidence for brown-dwarf secondary stars in this and other
cataclysmic variables.Comment: 6 pages, to appear in Monthly Notices, accepte
Many-spinon states and the secret significance of Young tableaux
We establish a one-to-one correspondence between the Young tableaux
classifying the total spin representations of N spins and the exact eigenstates
of the the Haldane-Shastry model for a chain with N sites classified by the
total spins and the fractionally spaced single-particle momenta of the spinons.Comment: 4 pages, 3 figure
Perturbative fragmentation of vector colored particle into bound states with a heavy antiquark
The fragmentation function of vector particle into possible bound S-wave
states with a heavy antiquark is calculated in the leading order of
perturbative QCD for the high energy processes at large transverse momenta with
the different behaviour of anomalous chromomagnetic moment. One-loop equations
are derived for the evolution of fragmentation function moments, which is
caused by the emission of hard gluons by the vector particle. The integrated
probabilities of fragmentation are given. The distribution of bound state over
the transverse momentum with respect to the axis of fragmentation is calculated
in the scaling limit.Comment: 10 pages, Latex file + 4 ps-figure
Colossal Effects in Transition Metal Oxides Caused by Intrinsic Inhomogeneities
The influence of quenched disorder on the competition between ordered states
separated by a first-order transition is investigated. A phase diagram with
features resembling quantum-critical behavior is observed, even using classical
models. The low-temperature paramagnetic regime consists of coexisting ordered
clusters, with randomly oriented order parameters. Extended to manganites, this
state is argued to have a colossal magnetoresistance effect. A scale T* for
cluster formation is discussed. This is the analog of the Griffiths
temperature, but for the case of two competing orders, producing a strong
susceptibility to external fields. Cuprates may have similar features,
compatible with the large proximity effect of the very underdoped regime.Comment: 4 pages, 4 figure
The cumulative overlap distribution function in realistic spin glasses
We use a sample-dependent analysis, based on medians and quantiles, to
analyze the behavior of the overlap probability distribution of the
Sherrington-Kirkpatrick and 3D Edwards-Anderson models of Ising spin glasses.
We find that this approach is an effective tool to distinguish between RSB-like
and droplet-like behavior of the spin-glass phase. Our results are in agreement
with a RSB-like behavior for the 3D Edwards-Anderson model.Comment: Version accepted in PRB. 12 pages, 10 figure
Temperature chaos is a non-local effect
Temperature chaos plays a role in important effects, like for example memory
and rejuvenation, in spin glasses, colloids, polymers. We numerically
investigate temperature chaos in spin glasses, exploiting its recent
characterization as a rare-event driven phenomenon. The peculiarities of the
transformation from periodic to anti-periodic boundary conditions in spin
glasses allow us to conclude that temperature chaos is non-local: no bounded
region of the system causes it. We precise the statistical relationship between
temperature chaos and the free-energy changes upon varying boundary conditions.Comment: 15 pages, 8 figures. Version accepted for publication in JSTA
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