3,772 research outputs found
Entropy production in full phase space for continuous stochastic dynamics
The total entropy production and its three constituent components are
described both as fluctuating trajectory-dependent quantities and as averaged
contributions in the context of the continuous Markovian dynamics, described by
stochastic differential equations with multiplicative noise, of systems with
both odd and even coordinates with respect to time reversal, such as dynamics
in full phase space. Two of these constituent quantities obey integral
fluctuation theorems and are thus rigorously positive in the mean by Jensen's
inequality. The third, however, is not and furthermore cannot be uniquely
associated with irreversibility arising from relaxation, nor with the breakage
of detailed balance brought about by non-equilibrium constraints. The
properties of the various contributions to total entropy production are
explored through the consideration of two examples: steady state heat
conduction due to a temperature gradient, and transitions between stationary
states of drift-diffusion on a ring, both in the context of the full phase
space dynamics of a single Brownian particle
A Randomized, Double-Blinded, Placebo-Controlled, Cross Over Study Evaluating the Efficacy and Safety of Timolol Ophthalmic Solution as an Acute Treatment of Migraine
Introduction. Daily oral beta-adrenoreceptor antagonist has been shown to be effective in preventing migraine headaches. Timolol 0.5% ophthalmic solution is a non-selective beta-adrenoreceptor antago- nist, where the primary use is for glaucoma. There have been case reports that timolol is effective in aborting or improving an acute migraine headache. The objective of this study was to assess the efficacy (decrease of ≥ 50% in pain scale at 120 minutes) of timolol 0.5% ophthalmic solution compared to placebo in acute treatment of migraine headache.
Methods.We performed a randomized, double-blind, crossover, placebo-controlled, study. Study entry criteria required subjects to have one to eight migraine episodes per month. The primary outcome was comparison of the change in a visual analog pain scale (VAS) at 120 minutes after taking the study medication. Study subjects were given a pain scale with a range of 1 (no pain) to 10 (most severe pain) to complete after onset of migraine but before administration of study drops and 120 minutes after administration of study drops. Improve- ment was defined as a ≥ 50% decrease in pain scale.
Results. Nineteen subjects completed the study and were used for analysis. The primary outcome changes in pain scale, 120 minutes after dose, showed a similar decrease for placebo and drug with a slightly wider 95% CI for placebo. Six subjects in each arm experi- enced a ≥ 50% decrease in pain scale.
Conclusion. These results support that timolol 0.5% ophthalmic solution is not an efficacious treatment for acute migraine headache
Race and Sex Differences in Correlates of Systolic Blood Pressure in Community-Dwelling Older Adults
Objectives: To describe correlates of measured systolic blood pressure (SBP) among community-dwelling older African American and White Medicare beneficiaries.
Methods: Participants completed an in-home assessment and factors significantly correlated with SBP were tested using multivariable models.
Results: Among the 958 participants (mean age= 75.3 [SD = 6.8]; 49% African American; 49% female; 52% rural) African Americans were more often diagnosed with hypertension, more likely on anti-hypertensives, and on more anti-hypertensive medications. SBP was 2.7 mmHg higher in African Americans than Whites (p=.03). SBP was higher in women than men. Multivariable models revealed differences in the factors associated with SBP by race/sex specific groups. Having a history of smoking and reports of being relaxed and free of tension were associated with higher SBP among African American men.
Discussion: Although more likely prescribed anti-hypertensives, mean SBP was higher for older African Americans than Whites. Results support the hypothesis that behavioral and psychosocial factors are more important correlates of SBP levels among older African Americans than among Whites
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A postsynaptic PI3K-cII dependent signaling controller for presynaptic homeostatic plasticity.
Presynaptic homeostatic plasticity stabilizes information transfer at synaptic connections in organisms ranging from insect to human. By analogy with principles of engineering and control theory, the molecular implementation of PHP is thought to require postsynaptic signaling modules that encode homeostatic sensors, a set point, and a controller that regulates transsynaptic negative feedback. The molecular basis for these postsynaptic, homeostatic signaling elements remains unknown. Here, an electrophysiology-based screen of the Drosophila kinome and phosphatome defines a postsynaptic signaling platform that includes a required function for PI3K-cII, PI3K-cIII and the small GTPase Rab11 during the rapid and sustained expression of PHP. We present evidence that PI3K-cII localizes to Golgi-derived, clathrin-positive vesicles and is necessary to generate an endosomal pool of PI(3)P that recruits Rab11 to recycling endosomal membranes. A morphologically distinct subdivision of this platform concentrates postsynaptically where we propose it functions as a homeostatic controller for retrograde, trans-synaptic signaling
Investigation of a Switchable Textile Communication System on the Human Body
In this paper, a switchable textile communication system working at 2.45 GHz ISM band is presented and studied for different locations within a realistic on-body environment. A 3D laser scanner is used to generate a numerical phantom of the measured subject to improve the accuracy of the simulations which are carried out for different body postures. For the off-body communications, the system is acting as an aperture coupled microstrip patch antenna with a boresight gain of 1.48 dBi. On-body communication is achieved by using a textile stripline, which gives approximately 5 dB transmission loss over 600 mm distance. The system is switched between on and off-body modes by PIN diodes. Common issues, such as shape distortion and body detuning effects which the textile antenna may experience in realistic use are fully discussed. Robust antenna performance is noted in the on-body tests, and an additional 3 dB transmission coefficient deduction was noticed in the most severe shape distortion case
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