700 research outputs found
Meta-Analysis of Genome-Wide Linkage Studies in Celiac Disease.
OBJECTIVE: A meta-analysis of genome-wide linkage studies allows us to summarize the extensive information available from family-based studies, as the field moves into genome-wide association studies.
METHODS: Here we apply the genome scan meta-analysis (GSMA) method, a rank-based, model-free approach, to combine results across eight independent genome-wide linkages performed on celiac disease (CD), including 554 families with over 1,500 affected individuals. We also investigate the agreement between signals we identified from this meta-analysis of linkage studies and those identified from genome-wide association analysis using a hypergeometric distribution.
RESULTS: Not surprisingly, the most significant result was obtained in the HLA region. Outside the HLA region, suggestive evidence for linkage was obtained at the telomeric region of chromosome 10 (10q26.12-qter; p = 0.00366), and on chromosome 8 (8q22.2-q24.21; p = 0.00491). Testing signals of association and linkage within bins showed no significant evidence for co-localization of results.
CONCLUSION: This meta-analysis allowed us to pool the results from available genome-wide linkage studies and to identify novel regions potentially harboring predisposing genetic variation contributing to CD. This study also shows that linkage and association studies may identify different types of disease-predisposing variants
Male breast cancer in BRCA1 and BRCA1 mutation carriers: pathology data from the consortium of investigators of Modifiers of BRCA1/2
published_or_final_versio
Separated cross sections in \pi^0 electroproduction at threshold at Q^2 = 0.05 GeV^2/c^2
The differential cross sections \sigma_0=\sigma_T+\epsilon \sigma_L,
\sigma_{LT}, and \sigma_{TT} of \pi^0 electroproduction from the proton were
measured from threshold up to an additional center of mass energy of 40 MeV, at
a value of the photon four-momentum transfer of Q^2= 0.05 GeV^2/c^2 and a
center of mass angle of \theta=90^\circ. By an additional out-of-plane
measurement with polarized electrons \sigma_{LT'} was determined. This showed
for the first time the cusp effect above the \pi^+ threshold in the imaginary
part of the s-wave. The predictions of Heavy Baryon Chiral Perturbation Theory
are in disagreement with these data. On the other hand, the data are somewhat
better predicted by the MAID phenomenological model and are in good agreement
with the dynamical model DMT.Comment: 6 pages, 4 figure
Founder populations and their uses for breast cancer genetics
Numerous founder mutations have been reported in BRCA1 and BRCA2. For genetic screening of a population with a founder mutation, testing can be targeted to the mutation, allowing for a more rapid and less expensive test. In addition, more precise estimates of the prior probability of carrying a mutation and of the likelihood of a mutation carrier developing cancer should be possible. For a given founder mutation a large number of carriers are available, so that focused scientific studies of penetrance, expression, and genetic and environmental modifiers of risk can be performed. Finally, founder populations may be a powerful resource to localize additional breast cancer susceptibility loci, because of the reduction in locus heterogeneity
New detectors for the kaon and hypernuclear experiments with KaoS at MAMI and with PANDA at GSI
The KaoS spectrometer at the Mainz Microtron MAMI, Germany, is perceived as
the ideal candidate for a dedicated spectrometer in kaon and hypernuclei
electroproduction. KaoS will be equipped with new read-out electronics, a
completely new focal plane detector package consisting of scintillating fibres,
and a new trigger system. First prototypes of the fibre detectors and the
associated new front-end electronics are shown in this contribution. The Mainz
hypernuclei research program will complement the hypernuclear experiments at
the planned FAIR facility at GSI, Germany. At the proposed antiproton storage
ring the spectroscopy of double Lambda hypernuclei is one of the four main
topics which will be addressed by the PANDA Collaboration. The experiments
require the operation of high purity germanium (HPGe) detectors in high
magnetic fields (B= 1T) in the presence of a large hadronic background. The
performance of high resolution Ge detectors in such an environment has been
investigated.Comment: Presentation at International Symposium on the Development of
Detectors for Particle, Astroparticle and Synchrotron Radiation Experiments,
Stanford, Ca (SNIC06), 6 pages, LaTeX, 11 eps figure
Measurement of the LT-asymmetry in \pi^0 electroproduction at the energy of the \Delta (1232) resonance
The reaction p(e,e'p)pi^0 has been studied at Q^2=0.2 (GeV/c)^2 in the region
of W=1232 MeV. From measurements left and right of q, cross section asymmetries
\rho_LT have been obtained in forward kinematics \rho_LT(\theta_\pi^0=20deg) =
(-11.68 +/- 2.36_stat +/- 2.36_sys)$ and backward kinematics
\rho_LT(\theta_\pi^0=160deg) =(12.18 +/- 0.27_stat +/- 0.82_sys). Multipole
ratios \Re(S_1+^* M_1+)/|M_1+|^2 and \Re(S_0+^* M_1+)/|M_1+|^2 were determined
in the framework of the MAID2003 model. The results are in agreement with older
data. The unusally strong negative \Re(S_0+^* M_1+)/|M_1+|^2 required to bring
also the result of Kalleicher et al. in accordance with the rest of the data is
almost excluded.Comment: 7 pages, 7 figures, 4 tables. Changed content. Accepted for
publication in EPJ
Final State Interaction Effects in pol 3He(pol e,e'p)
Asymmetries in quasi-elastic pol 3He(pol e,e'p) have been measured at a
momentum transfer of 0.67 (GeV/c)^2 and are compared to a calculation which
takes into account relativistic kinematics in the final state and a
relativistic one-body current operator. With an exact solution of the Faddeev
equation for the 3He-ground state and an approximate treatment of final state
interactions in the continuum good agreement is found with the experimental
data.Comment: 11 pages, 6 figures, submitted to Phys. Lett. B, revised version,
sensitivity study to relativity and NN-potential adde
Coherent \pi^0 threshold production from the deuteron at Q^2 = 0.1 GeV^2/c^2
First data on coherent threshold \pi^0 electroproduction from the deuteron
taken by the A1 Collaboration at the Mainz Microtron MAMI are presented. At a
four-momentum transfer of q^2=-0.1 GeV^2/c^2 the full solid angle was covered
up to a center-of-mass energy of 4 MeV above threshold. By means of a
Rosenbluth separation the longitudinal threshold s wave multipole and an upper
limit for the transverse threshold s wave multipole could be extracted and
compared to predictions of Heavy Baryon Chiral Perturbation Theory.Comment: 7 pages, 7 figures, latex2
Measurements of the \gamma * p --> \Delta(1232) reaction at low Q2
We report new p measurements in the
resonance at the low momentum transfer region utilizing the
magnetic spectrometers of the A1 Collaboration at MAMI. The mesonic cloud
dynamics are predicted to be dominant and appreciably changing in this region
while the momentum transfer is sufficiently low to be able to test chiral
effective calculations. The results disagree with predictions of constituent
quark models and are in reasonable agreement with dynamical calculations with
pion cloud effects, chiral effective field theory and lattice calculations. The
reported measurements suggest that improvement is required to the theoretical
calculations and provide valuable input that will allow their refinements
The first determination of Generalized Polarizabilities of the proton by a Virtual Compton Scattering experiment
Absolute differential cross sections for the reaction (e+p -> e+p+gamma) have
been measured at a four-momentum transfer with virtuality Q^2=0.33 GeV^2 and
polarization \epsilon = 0.62 in the range 33.6 to 111.5 MeV/c for the momentum
of the outgoing photon in the photon-proton center of mass frame. The
experiment has been performed with the high resolution spectrometers at the
Mainz Microtron MAMI. From the photon angular distributions, two structure
functions which are a linear combination of the generalized polarizabilities
have been determined for the first time.Comment: 4 pages, 3 figure
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