3,225 research outputs found
Nuclear Shell Structure and Chaotic Dynamics in Hexadecapole Deformation
The effect of an axially symmetric hexadecapole term is investigated in a
strongly deformed quadrupole potential. While the system is nonintegrable and
shows significant chaotic behaviour classically, the quantum mechanical
treatment not only produces a general smoothing effect with regard to chaos but
even yields a pronounced shell structure at certain hexadecapole strength
parameter values for oblate and prolate deformation.Comment: RevTeX + 4 figs. available from the authors, to appear in Phys.Rev.
Genetic and Immune Predictors for Hypersensitivity Syndrome to Antiepileptic Drugs
Hypersensitivity syndrome reactions (HSR) to antiepileptic drugs (AED) are associated with severe clinical cutaneous adverse reactions (SCAR).Our aims are: to assess HSRs to AEDs using the in vitro lymphocyte toxicity assay (LTA) in patients who manifested HSRs clinically, to correlate LTA results with the clinical syndrome, to correlate LTA results with the human leukocyte antigen (HLA) allele B*1502 (HLA-B*1502) positivity in a Han Chinese-Canadian population, and to determine the cytokine network in this population. HSR patients developed fever and cutaneous eruptions in the presence or absence of organ involvement within 8 weeks of exposure to carbamazepine (CBZ), phenytoin (PHY) or lamotrigine (LTG). Control patients received AEDs without presenting HSR. We investigated 10 CBZ-HSR (4 presented with Stevens-Johnson syndrome (SJS)), 24 CBZ-controls, 10 PHY-HSR (4 presented with drug-induced liver injury (DILI)), 24 PHY-controls, 6 LTG-HSR (1 SJS and 1 DILI) and 24 LTG-controls. There were 30 Han Chinese individuals (14 HSR patients and 16 controls) in our cohort. LTA toxicity greater than 12.5%±2.5% was considered positive. Differences among groups were determined by analysis of variance. In addition, we measured cytokine secretion in the patient sera between 1 month and 3 years after the event. All Han Chinese individuals and 30% of Caucasians were genotyped for HLA-B*1502.A perfect correlation (r=0.92) was observed between positive LTA and clinical diagnosis of DILI and SJS/toxic epidermal necrolysis (TEN). HLA-B*1502 positivity in Han Chinese is a predictor of CBZ-HSR and PHY-HSR. HLA-B*1502-negative Han Chinese receiving only CBZ or a combination of CBZ-PHY tolerated the drug(s) clinically, presenting negative CBZ-LTA and PHY-LTA. However, 3 patients presenting negative CBZ-LTA and PHY-LTA, as well as negative HLA-B*1502, showed positive LTG-LTA (38%, 28% and 25%, respectively), implying that they should not be prescribed LTG. Three patients had LTA positive to both PHY and CBZ, and 3 others had LTA positive to both PHY and LTG. Clinically, all six patients presented HSR to both drugs that they tested positive to (cross-reactivity). Patients were grouped based on the clinical presentation of their symptoms as only rash and fever or a triad that characterizes "true" HSR (rash, fever and DILI or SJS/TEN). Levels of pro-inflammatory cytokines were significantly higher in patient sera compared to control sera. More specifically, the highest levels of tumor necrosis factor (TNF)-α was measured in patients presenting "true" HSR, as were the apoptotic markers Fas, caspase 8 activity and M30. We concluded that LTA is sensitive for DILI and SJS/TEN regardless of drug or ethnicity. HSR prediction will prevent AED-induced morbidity. In Han Chinese, HLA-B*1502 positivity is a predictor for CBZ-HSR and PHY-HSR. Its negativity does not predict a negative LTG-HSR. There is cross-reactivity between AEDs. Additionally, T-cell cytokines and chemokines control the pathogenesis of SJS/TEN and DILI, contributing to apoptotic processes in the liver and in the skin
On the continuity of spectra for families of magnetic pseudodifferential operators
For families of magnetic pseudodifferential operators defined by symbols and
magnetic fields depending continuously on a real parameter , we show
that the corresponding family of spectra also varies continuously with
.Comment: 22 page
Nonabelian solutions in N=4, D=5 gauged supergravity
We consider static, nonabelian solutions in N=4, D=5 Romans' gauged
supergravity model. Numerical arguments are presented for the existence of
asymptotically anti-de Sitter configurations in the version of the
theory, with a dilaton potential presenting a stationary point. Considering the
version of the theory with a Liouville dilaton potential, we look for
configurations with unusual topology. A new exact solution is presented, and a
counterterm method is proposed to compute the mass and action.Comment: 15 pages, 4 figure
Field-induced suppression of the heavy-fermion state in YbRh_2Si_2
We report DC magnetization measurements on YbRh_2Si_2 at temperatures down to
0.04K, magnetic fields B<11.5T and under hydrostatic pressure P<1.3GPa. At
ambient pressure a kink at B*=9.9T indicates a new type of field-induced
transition from an itinerant to a localized 4f-state. This transition is
different from the metamagnetic transition observed in other heavy fermion
compounds, as here ferromagnetic rather than antiferromagnetic correlations
dominate below B*. Hydrostatic pressure experiments reveal a clear
correspondence of B* to the characteristic spin fluctuation temperature
determined from specific heat
Computing Probabilistic Bisimilarity Distances for Probabilistic Automata
The probabilistic bisimilarity distance of Deng et al. has been proposed as a
robust quantitative generalization of Segala and Lynch's probabilistic
bisimilarity for probabilistic automata. In this paper, we present a
characterization of the bisimilarity distance as the solution of a simple
stochastic game. The characterization gives us an algorithm to compute the
distances by applying Condon's simple policy iteration on these games. The
correctness of Condon's approach, however, relies on the assumption that the
games are stopping. Our games may be non-stopping in general, yet we are able
to prove termination for this extended class of games. Already other algorithms
have been proposed in the literature to compute these distances, with
complexity in and \textbf{PPAD}. Despite the
theoretical relevance, these algorithms are inefficient in practice. To the
best of our knowledge, our algorithm is the first practical solution.
The characterization of the probabilistic bisimilarity distance mentioned
above crucially uses a dual presentation of the Hausdorff distance due to
M\'emoli. As an additional contribution, in this paper we show that M\'emoli's
result can be used also to prove that the bisimilarity distance bounds the
difference in the maximal (or minimal) probability of two states to satisfying
arbitrary -regular properties, expressed, eg., as LTL formulas
Estimation of a Noise Level Using Coarse-Grained Entropy of Experimental Time Series of Internal Pressure in a Combustion Engine
We report our results on non-periodic experimental time series of pressure in
a single cylinder spark ignition engine. The experiments were performed for
different levels of loading. We estimate the noise level in internal pressure
calculating the coarse-grained entropy from variations of maximal pressures in
successive cycles. The results show that the dynamics of the combustion is a
nonlinear multidimensional process mediated by noise. Our results show that so
defined level of noise in internal pressure is not monotonous function of
loading.Comment: 12 pages, 6 figure
Two-stage Kondo effect in a four-electron artificial atom
An artificial atom with four electrons is driven through a singlet-triplet
transition by varying the confining potential. In the triplet, a Kondo peak
with a narrow dip at drain-source voltage V_ds=0 is observed. The low energy
scale V_ds* characterizing the dip is consistent with predictions for the
two-stage Kondo effect. The phenomenon is studied as a function of temperature
T and magnetic field B, parallel to the two-dimensional electron gas. The low
energy scales T* and B* are extracted from the behavior of the zero-bias
conductance and are compared to the low energy scale V_ds* obtained from the
differential conductance. Good agreement is found between kT* and |g|muB*, but
eV_ds* is larger, perhaps because of nonequilibrium effects.Comment: 7 pages, 7 figures. Added labels on Fig. 3f and one referenc
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