Facilitated movement of inertial Brownian motors driven by a load under an asymmetric potential

Based on recent work [L. Machura, M. Kostur, P. Talkner, J. Luczka, and P. Hanggi, Phys. Rev. Lett. 98, 040601 (2007)], we extend the study of inertial Brownian motors to the case of an asymmetric potential. It is found that some transport phenomena appear in the presence of an asymmetric potential. Within tailored parameter regimes, there exists two optimal values of the load at which the mean velocity takes its maximum, which means that a load can facilitate the transport in the two parameter regimes. In addition, the phenomenon of multiple current reversals can be observed when the load is increased.Comment: 7 pages, 3 figure

Transport of overdamped Brownian particles in a two-dimensional tube: Nonadiabatic regime

Transport of overdamped Brownian particles in a two-dimensional asymmetric tube is investigated in the presence of nonadiabatic periodic driving forces. By using Brownian dynamics simulations we can find that the phenomena in nonadiabatic regime differ from that in adiabatic case. The direction of the current can be reversed by tuning the driving frequency. Remarkably, the current as a function of the driving amplitude exhibits several local maxima at finite driving frequency.Comment: 10 pages, 4 figure

Low-energy diffraction; a direct-channel point of view: the background

We argue that at low-energies, typical of the resonance region, the contribution from direct-channel exotic trajectories replaces the Pomeron exchange, typical of high energies. A dual model realizing this idea is suggested. While at high energies it matches the Regge pole behavior, dominated by a Pomeron exchange, at low energies it produces a smooth, structureless behavior of the total cross section determined by a direct-channel nonlinear exotic trajectory, dual to the Pomeron exchange.Comment: 6 pages, 1 figure. Talk presented at the Second International "Cetraro" Workshop & NATO Advanced Research Workshop "Diffraction 2002", Alushta, Crimea, Ukraine, August 31 - September 6, 200

Dietary guideline adherence for gastroesophageal reflux disease.

BackgroundGastroesophageal reflux disease (GERD) is the most common gastrointestinal disease, and the cost of health care and lost productivity due to GERD is extremely high. Recently described side effects of long-term acid suppression have increased the interest in nonpharmacologic methods for alleviating GERD symptoms. We aimed to examine whether GERD patients follow recommended dietary guidelines, and if adherence is associated with the severity and frequency of reflux symptoms.MethodsWe conducted a population-based cross-sectional study within the Kaiser Permanente Northern California population, comparing 317 GERD patients to 182 asymptomatic population controls. All analyses adjusted for smoking and education.ResultsGERD patients, even those with moderate to severe symptoms or frequent symptoms, were as likely to consume tomato products and large portion meals as GERD-free controls and were even more likely to consume soft drinks and tea [odds ratio (OR) = 2.01 95% confidence interval (CI) 1.12-3.61; OR = 2.63 95% CI 1.24-5.59, respectively] and eat fried foods and high fat diet. The only reflux-triggering foods GERD patients were less likely to consume were citrus and alcohol [OR = 0.59; 95% CI: 0.35-0.97 for citrus; OR = 0.41 95% CI 0.19-0.87 for 1 + drink/day of alcohol]. The associations were similar when we excluded users of proton pump inhibitors.ConclusionsGERD patients consume many putative GERD causing foods as frequently or even more frequently than asymptomatic patients despite reporting symptoms. These findings suggest that, if dietary modification is effective in reducing GERD, substantial opportunities for nonpharmacologic interventions exist for many GERD patients

Avoidability of formulas with two variables

In combinatorics on words, a word $w$ over an alphabet $\Sigma$ is said to avoid a pattern $p$ over an alphabet $\Delta$ of variables if there is no factor $f$ of $w$ such that $f=h(p)$ where $h:\Delta^*\to\Sigma^*$ is a non-erasing morphism. A pattern $p$ is said to be $k$-avoidable if there exists an infinite word over a $k$-letter alphabet that avoids $p$. We consider the patterns such that at most two variables appear at least twice, or equivalently, the formulas with at most two variables. For each such formula, we determine whether it is $2$-avoidable, and if it is $2$-avoidable, we determine whether it is avoided by exponentially many binary words

ALMA Observations of a Candidate Molecular Outflow in an Obscured Quasar

We present Atacama Large Millimeter/Submillimeter Array (ALMA) CO (1-0) and CO (3-2) observations of SDSS J135646.10+102609.0, an obscured quasar and ultra-luminous infrared galaxy (ULIRG) with two merging nuclei and a known 20-kpc-scale ionized outflow. The total molecular gas mass is M_{mol} ~ 9^{+19}_{-6} x 10^8 Msun, mostly distributed in a compact rotating disk at the primary nucleus (M_{mol} ~ 3 x 10^8 Msun) and an extended tidal arm (M_{mol} ~ 5 x 10^8 Msun). The tidal arm is one of the most massive molecular tidal features known; we suggest that it is due to the lower chance of shock dissociation in this elliptical/disk galaxy merger. In the spatially resolved CO (3-2) data, we find a compact (r ~ 0.3 kpc) high velocity (v ~ 500 km/s) red-shifted feature in addition to the rotation at the N nucleus. We propose a molecular outflow as the most likely explanation for the high velocity gas. The outflowing mass of M_{mol} ~ 7 x 10^7 Msun and the short dynamical time of t_{dyn} ~ 0.6 Myr yield a very high outflow rate of \dot{M}_{mol} ~ 350 Msun/yr and can deplete the gas in a million years. We find a low star formation rate (< 16 Msun/yr from the molecular content and < 21 Msun/yr from the far-infrared spectral energy distribution decomposition) that is inadequate to supply the kinetic luminosity of the outflow (\dot{E} ~ 3 x 10^43 erg/s). Therefore, the active galactic nucleus, with a bolometric luminosity of 10^46 erg/s, likely powers the outflow. The momentum boost rate of the outflow (\dot{p}/(Lbol/c) ~ 3) is lower than typical molecular outflows associated with AGN, which may be related to its compactness. The molecular and ionized outflows are likely two distinct bursts induced by episodic AGN activity that varies on a time scale of 10^7 yr.Comment: 16 pages, 7 figures, ApJ accepte