3,928 research outputs found
Bis[μ-4-(1H-imidazol-3-ium-1-yl)benzoato-κ2 O:O′]bis[(methanol)tris(nitrato-κ2 O,O′)terbium(III)]
In the centrosymmetric dinuclear title complex, [Tb2(NO3)6(C10H8N2O2)2(CH3OH)2], the Tb atoms are bridged by the carboxylate groups of the two 4-(1H-imidazol-3-ium-1-yl)benzoate (iba) ligands. The iba ligand adopts a zwitterionic form with a protonated imidazole group. The Tb atom adopts a distorted tricapped trigonal–prismatic coordination geometry and is coordinated by six O atoms of three chelating nitrate ions, one O atom of the methanol molecule and two O atoms of two iba ligands. The intramolecular Tb⋯Tb separation is 5.1419 (3) Å. O—H⋯O and N—H⋯O hydrogen bonds connect complex molecules into a two-dimensional network
Top quark forward-backward asymmetry and charge asymmetry in left-right twin Higgs model
In order to explain the Tevatron anomaly of the top quark forward-backward
asymmetry in the left-right twin Higgs model, we choose to give up
the lightest neutral particle of field as a stable dark matter
candidate. Then a new Yukawa interaction for is allowed, which can be
free from the constraint of same-sign top pair production and contribute
sizably to . Considering the constraints from the production rates of
the top pair (), the top decay rates and invariant mass
distribution, we find that this model with such new Yukawa interaction can
explain measured at the Tevatron while satisfying the charge
asymmetry measured at the LHC.Moreover, this model predicts a
strongly correlation between at the LHC and at the
Tevatron, i.e., increases as increases.Comment: 17 pages, 9 figures; matches the published versio
Spectroscopic Evidence for Anisotropic S-Wave Pairing Symmetry in MgB2
Scanning tunneling spectroscopy of superconducting MgB ( K)
were studied on high-density pellets and c-axis oriented films. The sample
surfaces were chemically etched to remove surface carbonates and hydroxides,
and the data were compared with calculated spectra for all symmetry-allowed
pairing channels. The pairing potential () is best described by an
anisotropic s-wave pairing model, with , where is the angle relative to the
crystalline c-axis, meV, and meV.Comment: 4 pages and 3 figures. Submitted to Physical Review Letters.
Corresponding author: Nai-Chang Yeh (e-mail: [email protected]
Effect of sintering temperature under high pressure in the uperconductivity for MgB2
We report the effect of the sintering temperature on the superconductivity of
MgB2 pellets prepared under a high pressure of 3 GPa. The superconducting
properties of the non-heated MgB2 in this high pressure were poor. However, as
the sintering temperature increased, the superconducting properties were vastly
enhanced, which was shown by the narrow transition width for the resistivity
and the low-field magnetizations. This shows that heat treatment under high
pressure is essential to improve superconducting properties. These changes were
found to be closely related to changes in the surface morphology observed using
scanning electron microscopy.Comment: 3 Pages including 3 figure
Neural Signals Related to Outcome Evaluation Are Stronger in CA1 than CA3
We have shown previously that CA1 conveys significant neural signals necessary to update value of the chosen target, namely chosen value and reward signals. To better understand hippocampal neural processes related to valuation, we compared chosen value- and reward-related neural activity between the CA3 and CA1 regions. Single units were recorded with tetrodes from the dorsal CA3 and CA1 regions of rats performing a dynamic foraging task, and chosen value- and reward-related neural activity was estimated using a reinforcement learning model and multiple regression analyses. Neural signals for chosen value and reward converged in both CA3 and CA1 when a trial outcome was revealed. However, these neural signals were stronger in CA1 than CA3. Consequently, neural signals for reward prediction error and updated chosen value were stronger in CA1 than CA3. Together with our previous finding that CA1 conveys stronger value signals than the subiculum, our results raise the possibility that CA1 might play a particularly important role among hippocampal subregions in evaluating experienced events
Symbolic Violence and Social Control in the Post-Total Institution Era
Subsequent to the passage of the Community Mental Health Act in 1963, the Total Institutions described by Goffman have for the most part disappeared. Nonetheless, many writers charge that social control is still the primary function of mental health programs, even those that are identified as community-based. The new methods of control have not received widespread attention. In community-based programs control is operationalized in the form of symbolic violence. This paper examines the various factors that contribute to this style of violence
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