821 research outputs found
A novel locus for autosomal recessive primary microcephaly (MCPH6) maps to 13q12.2
Key points:
• Autosomal recessive primary microcephaly (MCPH) is a
genetic disorder in which an affected subject is born
with a head circumference >3 SD below the expected
mean and is mentally retarded.
• We report a novel locus (MCPH6) mapped to chromosome
13q12.2 in a Brazilian family.
• The minimal critical region spans 6 Mb between markers
AL139378GT17 and D13S1244 with a maximum
two point lod score of 6.25
An analysis of the FIR/RADIO Continuum Correlation in the Small Magellanic Cloud
The local correlation between far-infrared (FIR) emission and radio-continuum
(RC) emission for the Small Magellanic Cloud (SMC) is investigated over scales
from 3 kpc to 0.01 kpc. Here, we report good FIR/RC correlation down to ~15 pc.
The reciprocal slope of the FIR/RC emission correlation (RC/FIR) in the SMC is
shown to be greatest in the most active star forming regions with a power law
slope of ~1.14 indicating that the RC emission increases faster than the FIR
emission. The slope of the other regions and the SMC are much flatter and in
the range of 0.63-0.85. The slopes tend to follow the thermal fractions of the
regions which range from 0.5 to 0.95. The thermal fraction of the RC emission
alone can provide the expected FIR/RC correlation. The results are consistent
with a common source for ultraviolet (UV) photons heating dust and Cosmic Ray
electrons (CRe-s) diffusing away from the star forming regions. Since the CRe-s
appear to escape the SMC so readily, the results here may not provide support
for coupling between the local gas density and the magnetic field intensity.Comment: 19 pages, 7 Figure
The CMB power spectrum at l=30-200 from QMASK
We measure the cosmic microwave background (CMB) power spectrum on angular
scales l~30-200 (1-6 degrees) from the QMASK map, which combines the data from
the QMAP and Saskatoon experiments. Since the accuracy of recent measurements
leftward of the first acoustic peak is limited by sample-variance, the large
area of the QMASK map (648 square degrees) allows us to place among the
sharpest constraints to date in this range, in good agreement with BOOMERanG
and (on the largest scales) COBE/DMR. By band-pass-filtering the QMAP and
Saskatoon maps, we are able to spatially compare them scale-by-scale to check
for beam- and pointing-related systematic errors.Comment: Revised to match accepted PRD version. Substantially expanded. Window
functions, map and covariance matrix at
http://www.hep.upenn.edu/~xuyz/qmask.htm
Study of the nucleon-induced preequilibrium reactions in terms of the Quantum Molecular Dynamics
The preequilibrium (nucleon-in, nucleon-out) angular distributions of
Al, Ni and Zr have been analyzed in the energy region from
90 to 200 MeV in terms of the Quantum Moleculear Dynamics (QMD) theory. First,
we show that the present approach can reproduce the measured (p,xp') and (p,xn)
angular distributions leading to continuous final states without adjusing any
parameters. Second, we show the results of the detailed study of the
preequilibrium reaction processes; the step-wise contribution to the angular
distribution, comparison with the quantum-mechanical Feshbach-Kerman-Koonin
theory, the effects of momentum distribution and surface refraction/reflection
to the quasifree scattering. Finally, the present method was used to assess the
importance of multiple preequilibrium particle emission as a function of
projectile energy up to 1 GeV.Comment: 22pages, Revex is used, 10 Postscript figures are available by
request from [email protected]
Family Unification on an Orbifold
We construct a family-unified model on a Z_2xZ_2 orbifold in five dimensions.
The model is based on a supersymmetric SU(7) gauge theory. The gauge group is
broken by orbifold boundary conditions to a product of grand unified SU(5) and
SU(2)xU(1) flavor symmetry. The structure of Yukawa matrices is generated by an
interplay between spontaneous breaking of flavor symmetry and geometric factors
arising due to field localization in the extra dimension.Comment: 13 page
Non-vacuum Solutions of Bianchi Type VI_0 Universe in f(R) Gravity
In this paper, we solve the field equations in metric f(R) gravity for
Bianchi type VI_0 spacetime and discuss evolution of the expanding universe. We
find two types of non-vacuum solutions by taking isotropic and anisotropic
fluids as the source of matter and dark energy. The physical behavior of these
solutions is analyzed and compared in the future evolution with the help of
some physical and geometrical parameters. It is concluded that in the presence
of isotropic fluid, the model has singularity at and represents
continuously expanding shearing universe currently entering into phantom phase.
In anisotropic fluid, the model has no initial singularity and exhibits the
uniform accelerating expansion. However, the spacetime does not achieve
isotropy as in both of these solutions.Comment: 20 pages, 5 figures, accepted for publication in Astrophys. Space Sc
Lepton Flavour Violating Leptonic/Semileptonic Decays of Charged Leptons in the Minimal Supersymmetric Standard Model
We consider the leptonic and semileptonic (SL) lepton flavour violating (LFV)
decays of the charged leptons in the minimal supersymmetric standard model
(MSSM). The formalism for evaluation of branching fractions for the SL LFV
charged-lepton decays with one or two pseudoscalar mesons, or one vector meson
in the final state, is given. Previous amplitudes for the SL LFV charged-lepton
decays in MSSM are improved, for instance the -penguin amplitude is
corrected to assure the gauge invariance. The decays are studied not only in
the model-independent formulation of the theory in the frame of MSSM, but also
within the frame of the minimal supersymmetric SO(10) model within which the
parameters of the MSSM are determined. The latter model gives predictions for
the neutrino-Dirac Yukawa coupling matrix, once free parameters in the model
are appropriately fixed to accommodate the recent neutrino oscillation data.
Using this unambiguous neutrino-Dirac Yukawa couplings, we calculate the LFV
leptonic and SL decay processes assuming the minimal supergravity scenario. A
very detailed numerical analysis is done to constrain the MSSM parameters.
Numerical results for SL LFV processes are given, for instance for tau -> e
(mu) pi0, tau -> e (mu) eta, tau -> e (mu) eta', tau -> e (mu) rho0, tau -> e
(mu) phi, tau -> e (mu) omega, etc.Comment: 36 pages, 3 tables, 5 .eps figure
The significance of the largest scale CMB fluctuations in WMAP
We investigate anomalies reported in the Cosmic Microwave Background maps
from the Wilkinson Microwave Anisotropy Probe (WMAP) satellite on very large
angular scales and discuss possible interpretations. Three independent
anomalies involve the quadrupole and octopole:
1. The cosmic quadrupole on its own is anomalous at the 1-in-20 level by
being low (the cut-sky quadrupole measured by the WMAP team is more strikingly
low, apparently due to a coincidence in the orientation of our Galaxy of no
cosmological significance);
2. The cosmic octopole on its own is anomalous at the 1-in-20 level by being
very planar;
3. The alignment between the quadrupole and octopole is anomalous at the
1-in-60 level.
Although the a priori chance of all three occurring is 1 in 24000, the
multitude of alternative anomalies one could have looked for dilutes the
significance of such a posteriori statistics. The simplest small universe model
where the universe has toroidal topology with one small dimension of order half
the horizon scale, in the direction towards Virgo, could explain the three
items above. However, we rule this model out using two topological tests: the
S-statistic and the matched circle test.Comment: N.B. that our results do not rule out the recently proposed
dodecahedron model of Luminet, Weeks, Riazuelo, Lehoucq & Uzan, which has a
36 degree twist between matched circles. 12 pages, 5 figs; more info at
http://www.hep.upenn.edu/~angelica/topology.htm
Energy Linearity and Resolution of the ATLAS Electromagnetic Barrel Calorimeter in an Electron Test-Beam
A module of the ATLAS electromagnetic barrel liquid argon calorimeter was
exposed to the CERN electron test-beam at the H8 beam line upgraded for
precision momentum measurement. The available energies of the electron beam
ranged from 10 to 245 GeV. The electron beam impinged at one point
corresponding to a pseudo-rapidity of eta=0.687 and an azimuthal angle of
phi=0.28 in the ATLAS coordinate system. A detailed study of several effects
biasing the electron energy measurement allowed an energy reconstruction
procedure to be developed that ensures a good linearity and a good resolution.
Use is made of detailed Monte Carlo simulations based on Geant which describe
the longitudinal and transverse shower profiles as well as the energy
distributions. For electron energies between 15 GeV and 180 GeV the deviation
of the measured incident electron energy over the beam energy is within 0.1%.
The systematic uncertainty of the measurement is about 0.1% at low energies and
negligible at high energies. The energy resolution is found to be about 10%
sqrt(E) for the sampling term and about 0.2% for the local constant term
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