11,598 research outputs found
Hypocretin-1 receptors regulate the reinforcing and reward-enhancing effects of cocaine: pharmacological and behavioral genetics evidence.
Considerable evidence suggests that transmission at hypocretin-1 (orexin-1) receptors (Hcrt-R1) plays an important role in the reinstatement of extinguished cocaine-seeking behaviors in rodents. However, far less is known about the role for hypocretin transmission in regulating ongoing cocaine-taking behavior. Here, we investigated the effects of the selective Hcrt-R1 antagonist SB-334867 on cocaine intake, as measured by intravenous (IV) cocaine self-administration in rats. The stimulatory effects of cocaine on brain reward systems contribute to the establishment and maintenance of cocaine-taking behaviors. Therefore, we also assessed the effects of SB-334867 on the reward-enhancing properties of cocaine, as measured by cocaine-induced lowering of intracranial self-stimulation (ICSS) thresholds. Finally, to definitively establish a role for Hcrt-R1 in regulating cocaine intake, we assessed IV cocaine self-administration in Hcrt-R1 knockout mice. We found that SB-334867 (1-4 mg/kg) dose-dependently decreased cocaine (0.5 mg/kg/infusion) self-administration in rats but did not alter responding for food rewards under the same schedule of reinforcement. This suggests that SB-334867 decreased cocaine reinforcement without negatively impacting operant performance. SB-334867 (1-4 mg/kg) also dose-dependently attenuated the stimulatory effects of cocaine (10 mg/kg) on brain reward systems, as measured by reversal of cocaine-induced lowering of ICSS thresholds in rats. Finally, we found that Hcrt-R1 knockout mice self-administered far less cocaine than wildtype mice across the entire dose-response function. These data demonstrate that Hcrt-R1 play an important role in regulating the reinforcing and reward-enhancing properties of cocaine and suggest that hypocretin transmission is likely essential for establishing and maintaining the cocaine habit in human addicts
Low-Energy Properties of a One-dimensional System of Interacting bosons with Boundaries
The ground state properties and low-lying excitations of a (quasi)
one-dimensional system of longitudinally confined interacting bosons are
studied. This is achieved by extending Haldane's harmonic-fluid description to
open boundary conditions. The boson density, one-particle density matrix, and
momentum distribution are obtained accounting for finite-size and boundary
effects. Friedel oscillations are found in the density. Finite-size scaling of
the momentum distribution at zero momentum is proposed as a method to obtain
from the experiment the exponent that governs phase correlations. The strong
correlations between bosons induced by reduced dimensionality and interactions
are displayed by a Bijl-Jastrow wave function for the ground state, which is
also derived.Comment: Final published version. Minor changes with respect to the previous
versio
New Era, New Opportunity, Is GES DISC Ready for Big Data Challenge?
The new era of Big Data has opened doors for many new opportunities, as well as new challenges, for both Earth science research/application and data communities. As one of the twelve NASA data centers - Goddard Earth Sciences Data and Information Services Center (GES DISC), one of our great challenges has been how to help research/application community efficiently (quickly and properly) accessing, visualizing and analyzing the massive and diverse data in natural hazard research, management, or even prediction. GES DISC has archived over 2000 TB data on premises and distributed over 23,000 TB of data since 2010. Our data has been widely used in every phase of natural hazard management and research, i.e. long term risk assessment and reduction, forecasting and predicting, monitoring and detection, early warning, damage assessment and response. The big data challenge is not just about data storage, but also about data discoverability and accessibility, and even more, about data migration/mirroring in the cloud. This paper is going to demonstrate GES DISCs efforts and approaches of evolving our overall Web services and powerful Giovanni (Geospatial Interactive Online Visualization ANd aNalysis Infrastructure) tool into further improving data discoverability and accessibility. Prototype works will also be presented
mixing effects on charmonium and meson decays
We include the meson into the -- mixing formalism
constructed in our previous work, where represents the pseudoscalar
gluball. The mixing angles in this tetramixing matrix are constrained by
theoretical and experimental implications from relevant hadronic processes.
Especially, the angle between and is found to be about
from the measured decay widths of the meson. The pseudoscalar glueball
mass , the pseudoscalar densities and the U(1) anomaly
matrix elements associated with the mixed states are solved from the anomalous
Ward identities. The solution GeV obtained from the
-- mixing is confirmed, while grows to above the pion
mass, and thus increases perturbative QCD predictions for the branching ratios
. We then analyze the -mixing effects on charmonium
magnetic dipole transitions, and on the branching
ratios and CP asymmetries, which further improve the consistency between
theoretical predictions and data. A predominant observation is that the
mixing enhances the perturbative QCD predictions for
by 18%, but does not alter those for . The puzzle due to the
large data is then resolved.Comment: 12 pages, version to appear in PR
Ytterbium divalency and lattice disorder in near-zero thermal expansion YbGaGe
While near-zero thermal expansion (NZTE) in YbGaGe is sensitive to
stoichiometry and defect concentration, the NZTE mechanism remains elusive. We
present x-ray absorption spectra that show unequivocally that Yb is nearly
divalent in YbGaGe and the valence does not change with temperature or with
nominally 1% B or 5% C impurities, ruling out a valence-fluctuation mechanism.
Moreover, substantial changes occur in the local structure around Yb with B and
C inclusion. Together with inelastic neutron scattering measurements, these
data indicate a strong tendency for the lattice to disorder, providing a
possible explanation for NZTE in YbGaGe.Comment: 4 pages, 4 figure, supplementary inf
The Drinfel'd Double and Twisting in Stringy Orbifold Theory
This paper exposes the fundamental role that the Drinfel'd double \dkg of
the group ring of a finite group and its twists \dbkg, \beta \in
Z^3(G,\uk) as defined by Dijkgraaf--Pasquier--Roche play in stringy orbifold
theories and their twistings.
The results pertain to three different aspects of the theory. First, we show
that --Frobenius algebras arising in global orbifold cohomology or K-theory
are most naturally defined as elements in the braided category of
\dkg--modules. Secondly, we obtain a geometric realization of the Drinfel'd
double as the global orbifold --theory of global quotient given by the
inertia variety of a point with a action on the one hand and more
stunningly a geometric realization of its representation ring in the braided
category sense as the full --theory of the stack . Finally, we show
how one can use the co-cycles above to twist a) the global orbifold
--theory of the inertia of a global quotient and more importantly b) the
stacky --theory of a global quotient . This corresponds to twistings
with a special type of 2--gerbe.Comment: 35 pages, no figure
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