4,156 research outputs found
Kufor-Rakeb syndrome, pallido-pyramidal degeneration with supranuclear upgaze paresis and dementia, maps to 1p36
Kufor-Rakeb syndrome is an autosomal
recessive nigro-striatal-pallidal-pyramidal
neurodegeneration. The onset is in the
teenage years with clinical features of Parkinson’s
disease plus spasticity, supranuclear
upgaze paresis, and dementia. Brain
scans show atrophy of the globus pallidus
and pyramids and, later, widespread cerebral
atrophy. We report linkage in Kufor-
Rakeb syndrome to a 9 cM region of
chromosome 1p36 delineated by the markers
D1S436 and D1S2843, with a maximum
multipoint lod score of 3.6.
(J Med Genet 2001;38:680–682
Orbitally-driven Behavior: Mott Transition, Quantum Oscillations and Colossal Magnetoresistance in Bilayered Ca3Ru2O7
We report recent transport and thermodynamic experiments over a wide range of
temperatures for the Mott-like system Ca3Ru2O7 at high magnetic fields, B, up
to 30 T. This work reveals a rich and highly anisotropic phase diagram, where
applying B along the a-, b-, and c-axis leads to vastly different behavior. A
fully spin-polarized state via a first order metamagnetic transition is
obtained for B||a, and colossal magnetoresistance is seen for B||b, and quantum
oscillations in the resistivity are observed for B||c, respectively. The
interplay of the lattice, orbital and spin degrees of freedom are believed to
give rise to this strongly anisotropic behavior.Comment: 26 pages and 8 figure
Role of appetitive phenotype trajectory groups on child body weight during a family-based treatment for children with overweight or obesity.
ObjectiveEmerging evidence suggests that individual appetitive traits may usefully explain patterns of weight loss in behavioral weight loss treatments for children. The objective of this study was to identify trajectories of child appetitive traits and the impact on child weight changes over time.MethodsSecondary data analyses of a randomized noninferiority trial conducted between 2011 and 2015 evaluated children's appetitive traits and weight loss. Children with overweight and obesity (mean age = 10.4; mean BMI z = 2.0; 67% girls; 32% Hispanic) and their parent (mean age = 42.9; mean BMI = 31.9; 87% women; 31% Hispanic) participated in weight loss programs and completed assessments at baseline, 3, 6,12, and 24 months. Repeated assessments of child appetitive traits, including satiety responsiveness, food responsiveness and emotional eating, were used to identify parsimonious grouping of change trajectories. Linear mixed-effects models were used to identify the impact of group trajectory on child BMIz change over time.ResultsOne hundred fifty children and their parent enrolled in the study. The three-group trajectory model was the most parsimonious and included a high satiety responsive group (HighSR; 47.4%), a high food responsive group (HighFR; 34.6%), and a high emotional eating group (HighEE; 18.0%). Children in all trajectories lost weight at approximately the same rate during treatment, however, only the HighSR group maintained their weight loss during follow-ups, while the HighFR and HighEE groups regained weight (adjusted p-value < 0.05).ConclusionsDistinct trajectories of child appetitive traits were associated with differential weight loss maintenance. Identified high-risk subgroups may suggest opportunities for targeted intervention and maintenance programs
Autosomal recessive primary microcephaly: an analysis of locus heterogeneity and phenotypic variation
BACKGROUND AND OBJECTIVES: Locus heterogeneity is well established in autosomal recessive primary
microcephaly (MCPH) and to date five loci have been mapped. However, the relative contributions of
these loci have not been assessed and genotype-phenotype correlations have not been investigated.
DESIGN: A study population of 56 consanguineous families resident in or originating from northern
Pakistan was ascertained and assessed by the authors. A panel of microsatellite markers spanning
each of the MCPH loci was designed, against which the families were genotyped.
RESULTS: The head circumference of the 131 affected subjects ranged from 4 to 14 SD below the mean,
but there was little intrafamilial variation among affecteds (± 1 SD). MCPH5 was the most prevalent,
with 24/56 families consistent with linkage; 2/56 families were compatible with linkage to MCPH1,
10/56 to MCPH2, 2/56 to MCPH3, none to MCPH4, and 18/56 did not segregate with any of the
loci.
CONCLUSIONS: MCPH5 is the most common locus in this population. On clinical grounds alone, the
phenotype of families linked to each MCPH locus could not be distinguished. We have also shown that
further MCPH loci await discovery with a number of families as yet unlinked
Fixation and consensus times on a network: a unified approach
We investigate a set of stochastic models of biodiversity, population
genetics, language evolution and opinion dynamics on a network within a common
framework. Each node has a state, 0 < x_i < 1, with interactions specified by
strengths m_{ij}. For any set of m_{ij} we derive an approximate expression for
the mean time to reach fixation or consensus (all x_i=0 or 1). Remarkably in a
case relevant to language change this time is independent of the network
structure.Comment: 4+epsilon pages, two-column, RevTeX4, 3 eps figures; version accepted
by Phys. Rev. Let
Charged State of a Spherical Plasma in Vacuum
The stationary state of a spherically symmetric plasma configuration is
investigated in the limit of immobile ions and weak collisions. Configurations
with small radii are positively charged as a significant fraction of the
electron population evaporates during the equilibration process, leaving behind
an electron distribution function with an energy cutoff. Such charged plasma
configurations are of interest for the study of Coulomb explosions and ion
acceleration from small clusters irradiated by ultraintense laser pulses and
for the investigation of ion bunches propagation in a plasma
Vibration effects on heat transfer in cryogenic systems Quarterly progress report, Jul. 1 - Sep. 30, 1967
Water test apparatus used to determine vibration effects on heat transfer in cryogenic system
Reduction of a metapopulation genetic model to an effective one island model
We explore a model of metapopulation genetics which is based on a more
ecologically motivated approach than is frequently used in population genetics.
The size of the population is regulated by competition between individuals,
rather than by artificially imposing a fixed population size. The increased
complexity of the model is managed by employing techniques often used in the
physical sciences, namely exploiting time-scale separation to eliminate fast
variables and then constructing an effective model from the slow modes.
Remarkably, an initial model with 2 variables, where
is the number of islands in the metapopulation, can be reduced to a model with
a single variable. We analyze this effective model and show that the
predictions for the probability of fixation of the alleles and the mean time to
fixation agree well with those found from numerical simulations of the original
model.Comment: 16 pages, 4 figures. Supplementary material: 22 pages, 3 figure
A Powerful and Computationally Efficient Algorithm for Transmission Loss Calculation
This paper deals with the formulation of transmission loss PL of a power system through a set of new coefficients (A coefficients) which are extremely efficient, exact and robust and suitable for real time application. Results on a few IEEE test systems are exciting and encouraging. They demonstrate that these A coefficients faithfully represent the system loss, are extremely robust and need not be re-evaluated for changes in the system loading conditions either for evaluation of system loss or cost of generation for economic load dispatch
Random copying in space
Random copying is a simple model for population dynamics in the absence of
selection, and has been applied to both biological and cultural evolution. In
this work, we investigate the effect that spatial structure has on the
dynamics. We focus in particular on how a measure of the diversity in the
population changes over time. We show that even when the vast majority of a
population's history may be well-described by a spatially-unstructured model,
spatial structure may nevertheless affect the expected level of diversity seen
at a local scale. We demonstrate this phenomenon explicitly by examining the
random copying process on small-world networks, and use our results to comment
on the use of simple random-copying models in an empirical context.Comment: 26 pages, 11 figures. Based on invited talk at AHRC CECD Conference
on "Cultural Evolution in Spatially Structured Populations" at UCL, September
2010. To appear in ACS - Advances in Complex System
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