The effect of additive noise on dynamical hysteresis

We investigate the properties of hysteresis cycles produced by a one-dimensional, periodically forced Langevin equation. We show that depending on amplitude and frequency of the forcing and on noise intensity, there are three qualitatively different types of hysteresis cycles. Below a critical noise intensity, the random area enclosed by hysteresis cycles is concentrated near the deterministic area, which is different for small and large driving amplitude. Above this threshold, the area of typical hysteresis cycles depends, to leading order, only on the noise intensity. In all three regimes, we derive mathematically rigorous estimates for expectation, variance, and the probability of deviations of the hysteresis area from its typical value.Comment: 30 pages, 5 figure

Automated Telephone Monitoring for Relapse Risk among Recent Quitters Enrolled in Quitline Services

poster abstractThis study is part of a randomized controlled trial to test the efficacy of interactive voice response (IVR) technology for enhancing existing quitline services (Free & Clear’s Quit for Life® program) to prevent smoking relapse and achieve abstinence. The IVR system screens for six indicators of risk for relapse including smoking lapse, physical withdrawal symptoms, depressive symptoms, perceived stress, decreased self-efficacy for quitting, and decreased motivation to quit. Participants can screen positive on any one or more risks, resulting in a rollover call to a telephone counselor. There are two intervention arms that differ in timing and frequency of IVR screening. In the Technology Enhanced Quitline arm (TEQ-10), 10 automated calls are placed at decreasing frequency for 8 weeks post-quit (twice a week for the first two weeks, then weekly). The High Intensity Technology-Enhanced Quitline arm (TEQ-20) includes 20 IVR calls (daily for the first 2 weeks, then weekly). This preliminary analysis includes IVR data collected on calls from 4/12/2010 to 10/31/2010. 2620 calls were made to 98 participants in the two intervention arms, TEQ-10 (n=44) and TEQ-20 (n=54). The two arms did not differ significantly on demographics or comorbid conditions. Three outcomes were analyzed: completed screening assessments, positive screen for relapse risk, and smoking lapse (i.e., smoking even a puff since the last call). 136 of the 736 (18.5%) completed assessments were positive for relapse risk: 66 for smoking lapse (49%), 42 craving (31%), 32 depressive symptoms (24%), 27 lack of confidence (20%), 8 stress (6%), and 8 lack of motivation (6%). Logistic regression models (adjusted for age and gender), with GEE estimation to account for withinperson correlation, showed that compared to the TEQ-10 study group, participants in the TEQ-20 study group were more likely to complete assessments (OR=1.7; 95% CI=1.2-2.4), less likely to screen positive for relapse risk (OR=.3; 95% CI=.2-.6), and less likely to have smoked (OR=.2; 95% CI=.09-.4). These results indicate that frequent IVR monitoring during the immediate postquit period may have a positive effect on relapse risk

National surveillance for hemophilia inhibitors in the United States: Summary report of an expert meeting: National Inhibitor Surveillance in the U.S.

On March 12, 2012, the Centers for Disease Control and Prevention (CDC) held a meeting of its partners in hemophilia treatment, community-based organizations, industry, and government to review data and discuss implementation issues relevant to planned United States (U.S.) national inhibitor surveillance. Issues discussed included the current status of inhibitor surveillance in the United Kingdom (UK) and the US, the results of a US inhibitor surveillance feasibility study, proposed national surveillance schemes, laboratory testing and reporting issues and potential opportunities for future inhibitor-related research. It was concluded that implementation of a national program of inhibitor surveillance using standardized testing through an established public health registry along with patient and care provider education and targeted research provide the best opportunity to inform efforts to develop and evaluate effective prevention strategies

Beyond the Fokker-Planck equation: Pathwise control of noisy bistable systems

We introduce a new method, allowing to describe slowly time-dependent Langevin equations through the behaviour of individual paths. This approach yields considerably more information than the computation of the probability density. The main idea is to show that for sufficiently small noise intensity and slow time dependence, the vast majority of paths remain in small space-time sets, typically in the neighbourhood of potential wells. The size of these sets often has a power-law dependence on the small parameters, with universal exponents. The overall probability of exceptional paths is exponentially small, with an exponent also showing power-law behaviour. The results cover time spans up to the maximal Kramers time of the system. We apply our method to three phenomena characteristic for bistable systems: stochastic resonance, dynamical hysteresis and bifurcation delay, where it yields precise bounds on transition probabilities, and the distribution of hysteresis areas and first-exit times. We also discuss the effect of coloured noise.Comment: 37 pages, 11 figure

Support Service Use and Interest in Support Services among Distressed Family Caregivers of Lung Cancer Patients

This study examined support service use and interest in support services among distressed family caregivers of patients recently entering a comprehensive cancer care facility

A study of the diagnostic accuracy of the PHQ-9 in primary care elderly

<p>Abstract</p> <p>Background</p> <p>The diagnostic accuracy of the Patient Health Questionnaire-9 (PHQ-9) for assessment of depression in elderly persons in primary care settings in the United States has not been previously addressed. Thus, the purpose of this study was to evaluate the test performance of the PHQ-9 for detecting major and minor depression in elderly patients in primary care.</p> <p>Methods</p> <p>A prospective study of diagnostic accuracy was conducted in two primary care, university-based clinics in the Pacific Northwest of the United States. Seventy-one patients aged 65 years or older participated; all completed the PHQ-9 and the 15-item Geriatric Depression Scale (GDS) and underwent the Structured Clinical Interview for Depression (SCID). Sensitivity, specificity, area under the receiver operating characteristic (ROC) curve, and likelihood ratios (LRs) were calculated for the PHQ-9, the PHQ-2, and the 15-item GDS for major depression alone and the combination of major plus minor depression.</p> <p>Results</p> <p>Two thirds of participants were female, with a mean age of 78 and two chronic health conditions. Twelve percent met SCID criteria for major depression and 13% minor depression. The PHQ-9 had an area under the curve (AUC) of 0.87 (95% confidence interval [CI], 0.74-1.00) for major depression, while the PHQ-2 and the 15-item GDS each had an AUC of 0.81 (95% CI for PHQ-2, 0.64-0.98, and for 15-item GDS, 0.70-0.91; <it>P </it>= 0.551). For major and minor depression combined, the AUC for the PHQ-9 was 0.85 (95% CI, 0.73-0.96), for the PHQ-2, 0.80 (95% CI, 0.68-0.93), and for the 15-item GDS, 0.71 (95% CI, 0.55-0.87; <it>P </it>= 0.187).</p> <p>Conclusions</p> <p>Based on AUC values, the PHQ-9 performs comparably to the PHQ-2 and the 15-item GDS in identifying depression among primary care elderly.</p