6,095 research outputs found
Statistical Mechanics of finite arrays of coupled bistable elements
We discuss the equilibrium of a single collective variable characterizing a
finite set of coupled, noisy, bistable systems as the noise strength, the size
and the coupling parameter are varied. We identify distinct regions in
parameter space. The results obtained in prior works in the asymptotic infinite
size limit are significantly different from the finite size results. A
procedure to construct approximate 1-dimensional Langevin equation is adopted.
This equation provides a useful tool to understand the collective behavior even
in the presence of an external driving force
Vacuum fluctuations and the conditional homodyne detection of squeezed light
Conditional homodyne detection of quadrature squeezing is compared with
standard nonconditional detection. Whereas the latter identifies
nonclassicality in a quantitative way, as a reduction of the noise power below
the shot noise level, conditional detection makes a qualitative distinction
between vacuum state squeezing and squeezed classical noise. Implications of
this comparison for the realistic interpretation of vacuum fluctuations
(stochastic electrodynamics) are discussed.Comment: 14 pages, 7 figures, to appear in J. Opt. B: Quantum Semiclass. Op
Therapy of Canine Hyperlipidemia with Bezafibrate.
BackgroundBezafibrate (BZF) is effective in the treatment of hypertriglyceridemia in human patients, but there are no data on its use in dogs.ObjectiveTo assess the safety of BZF in hyperlipidemic dogs and its efficacy in decreasing serum triglyceride (TG) and cholesterol (CHO) concentrations.AnimalsForty-six dogs, 26 females and 20 males, mean (±SD) age of 9 (±3) years, with TG ≥150 mg/dL (33 dogs also were hypercholesterolemic [>300 mg/dL]).MethodsProspective, uncontrolled clinical trial. Dogs were treated with bezafibrate once daily, using 200 mg tablets at a dosage of 4-10 mg/kg (depending on body weight). Serum TG and CHO concentrations and alanine aminotransferase (ALT) and creatine kinase (CK) activity before and after 30 days of treatment were compared.ResultsSixteen dogs (34.8%) had primary hyperlipidemia, and 30 dogs (65.2%) had secondary hyperlipidemia (including spontaneous hyperadrenocorticism [41.3%, n = 19/46], chronic treatment with glucocorticoids [10.8%, n = 5/46], and hypothyroidism [15.2%, n = 7/46]). After 30 days, serum TG concentration normalized (<150 mg/dL) in 42 dogs (91.3%) and CHO concentration normalized (<270 mg/dL) in 22 of 33 dogs (66.7%). There was no difference in baseline TG concentration between the primary and secondary hyperlipidemia subgroups, but the decrease in TG concentration after treatment was greater in the primary hyperlipidemia subgroup. No adverse effects were observed, but ALT activity decreased significantly after 30 days of treatment.Conclusions and clinical importanceOver 30 days, BZF was safe and effective in treatment of primary and secondary hyperlipidemia in dogs
High-frequency effects in the FitzHugh-Nagumo neuron model
The effect of a high-frequency signal on the FitzHugh-Nagumo excitable model
is analyzed. We show that the firing rate is diminished as the ratio of the
high-frequency amplitude to its frequency is increased. Moreover, it is
demonstrated that the excitable character of the system, and consequently the
firing activity, is suppressed for ratios above a given threshold value. In
addition, we show that the vibrational resonance phenomenon turns up for
sufficiently large noise strength values.Comment: 4 pages, 4 figures (to appear in Physical Review E
Frequency and phase synchronization of two coupled neurons with channel noise
We study the frequency and phase synchronization in two coupled identical and
nonidentical neurons with channel noise. The occupation number method is used
to model the neurons in the context of stochastic Hodgkin-Huxley model in which
the strength of of channel noise is represented by ion channel cluster size of
the initiation region of neuron. It is shown that frequency synchronization
only was achieved at arbitrary value of couple strength as long as two neurons'
channel cluster sizes are the same. We also show that the relative phase of
neurons can display profuse dynamic behavior under the combined action of
coupling and channel noise. Both qualitative and quantitative descriptions are
applied to describe the transitions between those behaviors. Relevance of our
findings to controlling neural synchronization experimentally is discussed.Comment: 8 pages, 10 figure
Phosphoproteomics data classify hematological cancer cell lines according to tumor type and sensitivity to kinase inhibitors
This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
The Effects of the Peak-Peak Correlation on the Peak Model of Hierarchical Clustering
In two previous papers a semi-analytical model was presented for the
hierarchical clustering of halos via gravitational instability from peaks in a
random Gaussian field of density fluctuations. This model is better founded
than the extended Press-Schechter model, which is known to agree with numerical
simulations and to make similar predictions. The specific merger rate, however,
shows a significant departure at intermediate captured masses. The origin of
this was suspected as being the rather crude approximation used for the density
of nested peaks. Here, we seek to verify this suspicion by implementing a more
accurate expression for the latter quantity which accounts for the correlation
among peaks. We confirm that the inclusion of the peak-peak correlation
improves the specific merger rate, while the good behavior of the remaining
quantities is preserved.Comment: ApJ accepted. 15 pages, including 4 figures. Also available at
ftp://pcess1.am.ub.es/pub/ApJ/effectpp.ps.g
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