p-species integrable reaction-diffusion processes

We consider a process in which there are p-species of particles, i.e. A_1,A_2,...,A_p, on an infinite one-dimensional lattice. Each particle $A_i$ can diffuse to its right neighboring site with rate $D_i$, if this site is not already occupied. Also they have the exchange interaction A_j+A_i --> A_i+A_j with rate $r_{ij}.$ We study the range of parameters (interactions) for which the model is integrable. The wavefunctions of this multi--parameter family of integrable models are found. We also extend the 2--species model to the case in which the particles are able to diffuse to their right or left neighboring sites.Comment: 16 pages, LaTe

An interacting spin flip model for one-dimensional proton conduction

A discrete asymmetric exclusion process (ASEP) is developed to model proton conduction along one-dimensional water wires. Each lattice site represents a water molecule that can be in only one of three states; protonated, left-pointing, and right-pointing. Only a right(left)-pointing water can accept a proton from its left(right). Results of asymptotic mean field analysis and Monte-Carlo simulations for the three-species, open boundary exclusion model are presented and compared. The mean field results for the steady-state proton current suggest a number of regimes analogous to the low and maximal current phases found in the single species ASEP [B. Derrida, Physics Reports, {\bf 301}, 65-83, (1998)]. We find that the mean field results are accurate (compared with lattice Monte-Carlo simulations) only in the certain regimes. Refinements and extensions including more elaborate forces and pore defects are also discussed.Comment: 13pp, 6 fig

Facilitators and Barriers to Participation in a Peer Support Intervention for Veterans With Chronic Pain

OBJECTIVE: To understand facilitators and barriers to participation in a peer support intervention for self-management of chronic pain. METHODS: After completing a pilot intervention study, peer coaches and their veteran patients took part in a qualitative, semistructured interview to explore their experiences with the intervention. Data were analyzed using an immersion/crystallization approach. RESULTS: Three facilitators and 2 barriers to patient participation in a peer support intervention for veterans with chronic pain emerged. Facilitators were (1) having a shared identity as veterans, (2) being partnered with a person who also has chronic pain, and (3) support from the study staff. Barriers were (1) logistical challenges, and (2) challenges to motivation and engagement in the intervention. DISCUSSION: Awareness of facilitators and barriers to participation in a peer-supported self-management program for chronic pain, as well as strategies to capitalize on facilitators and mitigate barriers, are essential for further study and ultimate clinical implementation of such a program

Association between Stress Urinary Incontinence and Depressive Symptoms after Birth: the Czech ELSPAC Study

The study objectives were to (1) identify risk factors related to stress urinary incontinence (SUI) and postnatal depression (PD) after birth, and (2) investigate both possible directions of association between SUI and PD in population-based sample of Czech mothers. 3,701 nulliparous and multiparous women completed the self-reported questionnaires at 6 weeks and 6 months after birth and were included into the analyses of this prospective cohort study. Unadjusted and adjusted logistic regressions examined relationship between SUI a PD accounting for range of other risk factors. During the frst 6 months after birth, 650 mothers (17.6%) developed SUI and 641 (17.3%) displayed signs of PD. The mode of delivery, parity and higher BMI were associated with SUI. The rate of PD symptoms was higher in mothers with positive history of prenatal depression, and in divorced or widowed mothers. Both conditions were associated with worse self-reported health, back pain and stop-smoker status. Initially, SUI at 6 weeks was slightly, but signifcantly associated with onset of PD at 6 months (OR 1.51, 95% CI 1.02–2.23) while PD at 6 weeks was not signifcantly related to new cases of SUI at 6 months (OR 1.48, 95% CI 0.91–2.39). After full adjustment these OR reduced to 1.41 and 1.38 (both non-signifcant), respectively. SUI and PD are common conditions in women postpartum that share some risk factors. Our study suggests that both directions of their relationship are possible although a larger study is needed to confrm our fndings

Veterans’ Pain Management Goals: Changes During the Course of a Peer-led Pain Self-Management Program

Objective Goal setting is a common element of self-management support programs; however, little is known about the nature of patients’ goals or how goals change during pain self-management. The purpose of the current study is to explore how patients’ goals and views of goal setting change over the course of a peer-led pain self-management program. Methods Veterans (n = 16) completing a 4-month peer-led pain self-management program completed semi-structured interviews at baseline and follow-up regarding their goals for their pain. Interviews were analyzed using immersion/crystallization. Results Analyses revealed six themes: motivation to do something for their pain, more goal-oriented, actually setting goals, clarity of goal importance, more specific/measurable goal criteria, and more specific/measurable strategies. Conclusion The current analyses illustrate how participants’ goals can evolve over the course of a peer-led pain self-management program. Specifically, increased motivation, more openness to using goals, greater clarity of goal importance, more specific and measurable goals and strategies, and the influence of the peer coach relationship were described by participants. Practice implications Pain self-management interventions should emphasize goal setting, and development of specific, measurable goals and plans. Trainings for providers should address the potential for the provider-patient relationship, particularly peer providers, to facilitate motivation and goal setting

Exact time-dependent correlation functions for the symmetric exclusion process with open boundary

As a simple model for single-file diffusion of hard core particles we investigate the one-dimensional symmetric exclusion process. We consider an open semi-infinite system where one end is coupled to an external reservoir of constant density $\rho^\ast$ and which initially is in an non-equilibrium state with bulk density $\rho_0$. We calculate the exact time-dependent two-point density correlation function $C_{k,l}(t)\equiv -$ and the mean and variance of the integrated average net flux of particles $N(t)-N(0)$ that have entered (or left) the system up to time $t$. We find that the boundary region of the semi-infinite relaxing system is in a state similar to the bulk state of a finite stationary system driven by a boundary gradient. The symmetric exclusion model provides a rare example where such behavior can be proved rigorously on the level of equal-time two-point correlation functions. Some implications for the relaxational dynamics of entangled polymers and for single-file diffusion in colloidal systems are discussed.Comment: 11 pages, uses REVTEX, 2 figures. Minor typos corrected and reference 17 adde

Persistence in the One-Dimensional A+B -> 0 Reaction-Diffusion Model

The persistence properties of a set of random walkers obeying the A+B -> 0 reaction, with equal initial density of particles and homogeneous initial conditions, is studied using two definitions of persistence. The probability, P(t), that an annihilation process has not occurred at a given site has the asymptotic form $P(t) -> const + t^{-\theta}$, where $\theta$ is the persistence exponent (``type I persistence''). We argue that, for a density of particles $\rho >> 1$, this non-trivial exponent is identical to that governing the persistence properties of the one-dimensional diffusion equation, where $\theta \approx 0.1207$. In the case of an initially low density, $\rho_0 << 1$, we find $\theta \approx 1/4$ asymptotically. The probability that a site remains unvisited by any random walker (``type II persistence'') is also investigated and found to decay with a stretched exponential form, $P(t) \sim \exp(-const \rho_0^{1/2}t^{1/4})$, provided $\rho_0 << 1$. A heuristic argument for this behavior, based on an exactly solvable toy model, is presented.Comment: 11 RevTeX pages, 19 EPS figure

Factors Affecting Implementation of an Evidence-Based Practice in the VA: Illness Management and Recovery

Objective: Illness management and recovery (IMR) is an evidence-based practice that assists consumers in managing their illnesses and pursuing personal recovery goals. Although research has examined factors affecting IMR implementation facilitated by multifaceted, active roll-outs, the current study attempted to elucidate factors affecting IMR implementation outside the context of a research-driven implementation. Methods: Semi-structured interviews with 20 local recovery coordinators and 18 local IMR experts were conducted at 23 VA medical centers. Interviews examined perceived and experienced barriers and facilitators to IMR implementation. Data were analyzed via thematic inductive/deductive analysis in the form of crystallization/immersion. Results: Six factors differed between sites implementing IMR from those not providing IMR: awareness of IMR, importer-champions, autonomy-supporting leadership, veteran-centered care, presence of a sensitive period, and presence of a psychosocial rehabilitation and recovery center. Four factors were common in both groups: recovery orientation, evidence-based practices orientation, perceived IMR fit within program structure, and availability of staff time. Conclusions and Implications for Practice: IMR can be adopted in lieu of active implementation support; however, knowledge dissemination appears to be key. Future research should examine factors affecting the quality of implementation. (PsycINFO Database Record (c) 2016 APA, all rights reserved