83 research outputs found
On the Critical Temperature of Non-Periodic Ising Models on Hexagonal Lattices
The critical temperature of layered Ising models on triangular and honeycomb
lattices are calculated in simple, explicit form for arbitrary distribution of
the couplings.Comment: to appear in Z. Phys. B., 8 pages plain TEX, 1 figure available upon
reques
Zero--Temperature Quantum Phase Transition of a Two--Dimensional Ising Spin--Glass
We study the quantum transition at in the spin- Ising
spin--glass in a transverse field in two dimensions. The world line path
integral representation of this model corresponds to an effective classical
system in (2+1) dimensions, which we study by Monte Carlo simulations. Values
of the critical exponents are estimated by a finite-size scaling analysis. We
find that the dynamical exponent, , and the correlation length exponent,
, are given by and . Both the linear
and non-linear susceptibility are found to diverge at the critical point.Comment: RevTeX 10 pages + 4 figures (appended as uuencoded, compressed
tar-file), THP21-9
Random bond Ising chain in a transverse magnetic field: A finite-size scaling analysis
We investigate the zero-temperature quantum phase transition of the random
bond Ising chain in a transverse magnetic field. Its critical properties are
identical to those of the McCoy-Wu model, which is a classical Ising model in
two dimensions with layered disorder. The latter is studied via Monte Carlo
simulations and transfer matrix calculations and the critical exponents are
determined with a finite-size scaling analysis. The magnetization and
susceptibility obey conventional rather than activated scaling. We observe that
the order parameter-- and correlation function--probability distribution show a
nontrivial scaling near the critical point which implies a hierarchy of
critical exponents associated with the critical behavior of the generalized
correlation lengths.Comment: RevTeX 13 pages + 4 figures (appended as uuencoded compressed
tar-file), THP61-9
Common trends in the critical behavior of the Ising and directed walk models
We consider layered two-dimensional Ising and directed walk models and show
that the two problems are inherently related. The information about the
zero-field thermodynamical properties of the Ising model is contained into the
transfer matrix of the directed walk. For several hierarchical and aperiodic
distributions of the couplings, critical exponents for the two problems are
obtained exactly through renormalization.Comment: 4 pages, RevTeX file + 1 figure, epsf needed. To be published in PR
Orexin Receptor Antagonism, a New Sleep-Enabling Paradigm: A Proof-of-Concept Clinical Trial
Peer reviewe
Glycyrrhizin Exerts Antioxidative Effects in H5N1 Influenza A Virus-Infected Cells and Inhibits Virus Replication and Pro-Inflammatory Gene Expression
Glycyrrhizin is known to exert antiviral and anti-inflammatory effects. Here, the effects of an approved parenteral glycyrrhizin preparation (Stronger Neo-Minophafen C) were investigated on highly pathogenic influenza A H5N1 virus replication, H5N1-induced apoptosis, and H5N1-induced pro-inflammatory responses in lung epithelial (A549) cells. Therapeutic glycyrrhizin concentrations substantially inhibited H5N1-induced expression of the pro-inflammatory molecules CXCL10, interleukin 6, CCL2, and CCL5 (effective glycyrrhizin concentrations 25 to 50 µg/ml) but interfered with H5N1 replication and H5N1-induced apoptosis to a lesser extent (effective glycyrrhizin concentrations 100 µg/ml or higher). Glycyrrhizin also diminished monocyte migration towards supernatants of H5N1-infected A549 cells. The mechanism by which glycyrrhizin interferes with H5N1 replication and H5N1-induced pro-inflammatory gene expression includes inhibition of H5N1-induced formation of reactive oxygen species and (in turn) reduced activation of NFκB, JNK, and p38, redox-sensitive signalling events known to be relevant for influenza A virus replication. Therefore, glycyrrhizin may complement the arsenal of potential drugs for the treatment of H5N1 disease
Fostering team creativity: Perspective taking as key to unlocking diversity's potential
In organizations, creative work is often carried out in teams, yet the mechanisms that lead teams to perform well on creative tasks are not well understood. Drawing on previous research, we argue that reframing, defined as a switch in the frame of reference from which a problem is approached, constitutes an important process to consider in explaining creative benefits on the group level. Based on an analysis of the relevant literature on group composition and processes we identify the interplay of a group's diversity and the degree to which group members engage in perspective taking as crucial antecedents to both reframing and group level creativity. We hypothesize that perspective taking moderates the effect of functional role diversity on group creativity and that this moderation effect is mediated by reframing. Results of a group experiment manipulating both diversity and perspective taking in students groups (N=77) performing a creative task largely confirm our propositions. Perspective taking and diversity interact to predict group creativity. Furthermore, audio-video coded use of reframing in the group interaction partially mediates this moderated effect. Our results indicate the importance of perspective taking to realize the potential diverse groups hold. Accordingly, in order to increase our knowledge on how to manage diverse teams, further research of the factors conducive to perspective taking represents a promising avenue for future research
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