938 research outputs found
Transport of a quantum degenerate heteronuclear Bose-Fermi mixture in a harmonic trap
We report on the transport of mixed quantum degenerate gases of bosonic 87Rb
and fermionic 40K in a harmonic potential provided by a modified QUIC trap. The
samples are transported over a distance of 6 mm to the geometric center of the
anti-Helmholtz coils of the QUIC trap. This transport mechanism was implemented
by a small modification of the QUIC trap and is free of losses and heating. It
allows all experiments using QUIC traps to use the highly homogeneous magnetic
fields that can be created in the center of a QUIC trap and improves the
optical access to the atoms, e.g., for experiments with optical lattices. This
mechanism may be cascaded to cover even larger distances for applications with
quantum degenerate samples.Comment: 7 pages, 8 figure
The copy number variant involving part of the \u3b17 nicotinic receptor gene contains a polymorphic inversion.
The \u3b17 nicotinic acetylcholine receptor gene (CHRNA7) is located at 15q13\u2013q14 in a region that is strongly linked to the P50 sensory gating deficit, an endophenotype of schizophrenia and bipolar disorder. Part of the gene is a copy number variant, due to a duplication of exons 5\u201310 and 3\u2032 sequence in CHRFAM7A, which is present in many but not all humans. Maps of this region show that the two genes are in opposite orientation in the individual mainly represented in the public access human DNA sequence database (Build 36), suggesting that an inversion had occurred since the duplication. We have used fluorescent in situ hybridization to investigate this putative inversion. Analysis of interphase chromosomes in 12 individuals confirms the occurrence of an inversion and indicates that CHRFAM7A exists in both orientations with similar frequency. We showed that the 2\u2009bp deletion polymorphism in exon 6 of CHRFAM7A is in strong linkage disequilibrium with the inversion polymorphism (r2=0.82, CI 0.53\u20131.00, P=0.00003), which can therefore be used as a surrogate marker. Previous associations of endophenotypes of schizophrenia with the 2\u2009bp deletion might therefore be due to the orientation of the duplicon containing CHRFAM7A
Near-threshold production of omega mesons in the pn -> d omega reaction
The first measurement of the p n -> d omega total cross section has been
achieved at mean excess energies of Q = 28 and 57 MeV by using a deuterium
cluster-jet target. The momentum of the fast deuteron was measured in the ANKE
spectrometer at COSY-Juelich and that of the slow "spectator" proton p(sp) from
the p d -> p(sp) d omega reaction in a silicon telescope placed close to the
target. The cross sections lie above those measured for p p -> p p omega but
seem to be below theoretical predictions.Comment: 7 pages, 8 figures; second approach to describe the background has
been added; results changed insignificantly, EPJ in pres
Extended morphometric analysis of neuronal cells with Minkowski valuations
Minkowski valuations provide a systematic framework for quantifying different
aspects of morphology. In this paper we apply vector- and tensor-valued
Minkowski valuations to neuronal cells from the cat's retina in order to
describe their morphological structure in a comprehensive way. We introduce the
framework of Minkowski valuations, discuss their implementation for neuronal
cells and show how they can discriminate between cells of different types.Comment: 14 pages, 18 postscript figure
Electron Radiated Power in Cyclotron Radiation Emission Spectroscopy Experiments
The recently developed technique of Cyclotron Radiation Emission Spectroscopy
(CRES) uses frequency information from the cyclotron motion of an electron in a
magnetic bottle to infer its kinetic energy. Here we derive the expected radio
frequency signal from an electron in a waveguide CRES apparatus from first
principles. We demonstrate that the frequency-domain signal is rich in
information about the electron's kinematic parameters, and extract a set of
measurables that in a suitably designed system are sufficient for disentangling
the electron's kinetic energy from the rest of its kinematic features. This
lays the groundwork for high-resolution energy measurements in future CRES
experiments, such as the Project 8 neutrino mass measurement.Comment: 15 pages, 10 figure
Identification of the TeV Gamma-ray Source ARGO J2031+4157 with the Cygnus Cocoon
The extended TeV gamma-ray source ARGO J2031+4157 (or MGRO J2031+41) is
positionally consistent with the Cygnus Cocoon discovered by -LAT at GeV
energies in the Cygnus superbubble. Reanalyzing the ARGO-YBJ data collected
from November 2007 to January 2013, the angular extension and energy spectrum
of ARGO J2031+4157 are evaluated. After subtracting the contribution of the
overlapping TeV sources, the ARGO-YBJ excess map is fitted with a
two-dimensional Gaussian function in a square region of , finding a source extension =
1.80.5. The observed differential energy spectrum is
photons cm
s TeV, in the energy range 0.2-10 TeV. The angular extension is
consistent with that of the Cygnus Cocoon as measured by -LAT, and the
spectrum also shows a good connection with the one measured in the 1-100 GeV
energy range. These features suggest to identify ARGO J2031+4157 as the
counterpart of the Cygnus Cocoon at TeV energies. The Cygnus Cocoon, located in
the star-forming region of Cygnus X, is interpreted as a cocoon of freshly
accelerated cosmic rays related to the Cygnus superbubble. The spectral
similarity with Supernova Remnants indicates that the particle acceleration
inside a superbubble is similar to that in a SNR. The spectral measurements
from 1 GeV to 10 TeV allows for the first time to determine the possible
spectrum slope of the underlying particle distribution. A hadronic model is
adopted to explain the spectral energy distribution.Comment: 16 pages, 3 figures, has been accepted by ApJ for publicatio
Observation of the TeV gamma-ray source MGRO J1908+06 with ARGO-YBJ
The extended gamma ray source MGRO J1908+06, discovered by the Milagro air
shower detector in 2007, has been observed for about 4 years by the ARGO-YBJ
experiment at TeV energies, with a statistical significance of 6.2 standard
deviations. The peak of the signal is found at a position consistent with the
pulsar PSR J1907+0602. Parametrizing the source shape with a two-dimensional
Gauss function we estimate an extension \sigma = 0.49 \pm 0.22 degrees,
consistent with a previous measurement by the Cherenkov Array H.E.S.S.. The
observed energy spectrum is dN/dE = 6.1 \pm 1.4 \times 10^-13 (E/4 TeV)^{-2.54
\pm 0.36} photons cm^-2 s^-1 TeV^-1, in the energy range 1-20 TeV. The measured
gamma ray flux is consistent with the results of the Milagro detector, but is
2-3 times larger than the flux previously derived by H.E.S.S. at energies of a
few TeV. The continuity of the Milagro and ARGO-YBJ observations and the stable
excess rate observed by ARGO-YBJ along 4 years of data taking support the
identification of MGRO J1908+06 as the steady powerful TeV pulsar wind nebula
of PSR J1907+0602, with an integrated luminosity above 1 TeV about 1.8 times
the Crab Nebula luminosity.Comment: 6 pages, accepted for pubblication by ApJ. Replaced to correct the
author lis
Strange particle production in proton-proton collisions at TeV with ALICE at the LHC
The production of mesons containing strange quarks (K, ) and both
singly and doubly strange baryons (, Anti-, and
+Anti-) are measured at central rapidity in pp collisions at
= 0.9 TeV with the ALICE experiment at the LHC. The results are
obtained from the analysis of about 250 k minimum bias events recorded in 2009.
Measurements of yields (dN/dy) and transverse momentum spectra at central
rapidities for inelastic pp collisions are presented. For mesons, we report
yields () of 0.184 0.002 stat. 0.006 syst. for K and
0.021 0.004 stat. 0.003 syst. for . For baryons, we find
= 0.048 0.001 stat. 0.004 syst. for , 0.047
0.002 stat. 0.005 syst. for Anti- and 0.0101 0.0020 stat.
0.0009 syst. for +Anti-. The results are also compared with
predictions for identified particle spectra from QCD-inspired models and
provide a baseline for comparisons with both future pp measurements at higher
energies and heavy-ion collisions.Comment: 33 pages, 21 captioned figures, 10 tables, authors from page 28,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/387
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