Stokes flow analogous to viscous electron current in graphene

Electron transport in two-dimensional conducting materials such as graphene, with dominant electron-electron interaction, exhibits unusual vortex flow that leads to a nonlocal current-field relation (negative resistance), distinct from the classical Ohm's law. The transport behavior of these materials is best described by low Reynolds number hydrodynamics, where the constitutive pressure-speed relation is Stoke's law. Here we report evidence of such vortices observed in a viscous flow of Newtonian fluid in a microfluidic device consisting of a rectangular cavity$-$analogous to the electronic system. We extend our experimental observations to elliptic cavities of different eccentricities, and validate them by numerically solving bi-harmonic equation obtained for the viscous flow with no-slip boundary conditions. We verify the existence of a predicted threshold at which vortices appear. Strikingly, we find that a two-dimensional theoretical model captures the essential features of three-dimensional Stokes flow in experiments.Comment: 6 pages, 6 figure

Barriers and solutions to addressing tobacco dependence in addiction treatment programs.

Despite the high prevalence of tobacco use among people with substance use disorders, tobacco dependence is often overlooked in addiction treatment programs. Several studies and a meta-analytic review have concluded that patients who receive tobacco dependence treatment during addiction treatment have better overall substance abuse treatment outcomes compared with those who do not. Barriers that contribute to the lack of attention given to this important problem include staff attitudes about and use of tobacco, lack of adequate staff training to address tobacco use, unfounded fears among treatment staff and administration regarding tobacco policies, and limited tobacco dependence treatment resources. Specific clinical-, program-, and system-level changes are recommended to fully address the problem of tobacco use among alcohol and other drug abuse patients

Rimonabant for treating tobacco dependence

Tobacco use continues to cause 5 million preventable deaths worldwide each year. Despite effective treatments being available, these are underutilized and cessation rates remain low. As tobacco use has complex physiological effects, there are multiple opportunities for novel pharmacological agents to play a role in a comprehensive treatment plan. The endocannabinoid system has been linked to the nicotine reward pathways in animal models. Rimonabant, a selective cannabinoid receptor (type 1) blocker, has been shown in some early clinical trials to have some positive effects in increasing abstinence rates of smokers attempting to stop. In addition, smokers who stop smoking with the assistance of rimonabant may gain less weight than those using placebo. However, the results from these few trials have not been entirely consistent and so its role as an aid to smoking cessation remains to be determined

Cardiac resynchronization therapy and atrial fibrillation

Cardiac resynchronization therapy (CRT) is an important advance for the treatment of end-stage heart failure (HF). About 15-50% of HF is complicated by atrial fibrillation (AF), associated with worsened outcomes. The presence of AF may interfere with optimal delivery of CRT due to competition with biventricular (BiV) capture by conducted beats. Pacing algorithms in newer devices may not ensure consistent CRT delivery during periods of rapid ventricular rates. Atrioventricular junction ablation with permanent pacing eliminates interference by conducted beats and provides complete BiV capture and is associated with improved outcomes. Catheter ablation of AF is another promising alternative to maintain sinus rhythm in patients with AF and HF. However, the optimal indications for CRT delivery for patients in this complex cohort remain to be assessed in randomized clinical trials

Hierarchies for Semidefinite Optimization in C⋆\mathcal{C}^\star-Algebras

Semidefinite Optimization has become a standard technique in the landscape of Mathematical Programming that has many applications in finite dimensional Quantum Information Theory. This paper presents a way for finite-dimensional relaxations of general cone programs on $\mathcal{C}^\star$-algebras which have structurally similar properties to ordinary cone programs, only putting the notion of positivity at the core of optimization. We show that well-known hierarchies for generalized problems like NPA but also Lasserre's hierarchy and to some extend symmetry reductions of generic SDPs by de-Klerk et al. can be considered from a general point of view of $\mathcal{C}^\star$-algebras in combination to optimization problems