Vibrating soap films: An analog for quantum chaos on billiards

We present an experimental setup based on the normal modes of vibrating soap films which shows quantum features of integrable and chaotic billiards. In particular, we obtain the so-called scars -narrow linear regions with high probability along classical periodic orbits- for the classically chaotic billiards. We show that these scars are also visible at low frequencies. Finally, we suggest some applications of our experimental setup in other related two-dimensional wave phenomena.Comment: 5 pages, 7 figures. Better Postscript figures available on reques

"Winning isn't everything": The Re-Nomination of Losing Candidates

Why do parties re-nominate losing candidates? This project develops a comparative theory for losers of elections, who are not a monolithic group of low-quality non-winners. We advance that political parties take note of two moments, one before the election and one after the race. These moments consider the electoral experience and the electoral performance of the candidate, respectively. Thus, we contend that parties treat experienced candidates differently from amateurs, and over-performers differently than under-performers when considering their futures in the electoral arena, despite all being equally losing candidates. For our empirical chapters, we explore the Chilean legislative elections, where an “insurance policy” mechanism for good losers developed mainly because of the electoral system in place since the return of democracy in 1989. This arrangement consisted of valuable appointments for candidates who were unable to win a legislative seat. Our exploration of the main question is twofold: first, we look at the seven legislative elections from 1989 to 2013, assessing the determinants of re-nomination, along with other outcomes that losing candidates followed. Second, we analyze the use of presidential appointments – to cabinet, embassies, or top regional executive positions – before and after the 2015 electoral reform, comparing the 2017 elections to the period including the seven races under the binominal electoral system. For the first empirical section, chapter 3, our main finding tells us that losing candidates who over-perform with respect to previous candidates for the same coalition in the same district are re-nominated in greater numbers than all other also-rans. Meanwhile, our second empirical section shows a continuous use of presidential appointments across both periods, pre and post-reform. Expanding the understanding of elections to include losing candidates – especially after realizing that some of these unsuccessful politicians come back to win elections – is a pending task for political scientists. We hope this is the start of a more nuanced discussion about the topic, with a framework that can be expanded to other countries. Similarly, these results can be complemented by qualitative studies with interviews to also-rans who are now winners, or to perennial losers, to gauge their strategies after being confronted with electoral defeat.Political Science, Department o

Can a Wi-Fi WLAN support a first person shooter?

In corporate and commercial environments, the deployment of a set of coordinated Wi-Fi APs is becoming a common solution to provide Internet coverage to moving users. In these scenarios, real-time services as online games can also be present. This paper presents a set of experiments developed in a test scenario where an end device moves between different APs while generating game traffic. A WLAN solution based on virtual APs is used, in order to make the handoffs transparent for Layer 3. The results show that it is possible to maintain an acceptable level of subjective quality during the handoff. At the same time, it is set clear that the fact of having a gamer in an AP could be taken into account by radio resource management algorithms, in order to provide a better quality

A single baseline ultrasound assessment of fibroid presence and size is strongly predictive of future uterine procedure: 8-year follow-up of randomly sampled premenopausal women aged 35-49 years.

STUDY QUESTION: How well can a single baseline ultrasound assessment of fibroid burden (presence or absence of fibroids and size of largest, if present) predict future probability of having a major uterine procedure? SUMMARY ANSWER: During an 8-year follow-up period, the risk of having a major uterine procedure was 2% for those without fibroids and increased with fibroid size for those with fibroids, reaching 47% for those with fibroids ≥4 cm in diameter at baseline. WHAT IS KNOWN ALREADY: Uterine fibroids are a leading indication for hysterectomy. However, when fibroids are found, there are few available data to help clinicians advise patients about disease progression. STUDY DESIGN, SIZE, DURATION: Women who were 35-49 years old were randomly selected from the membership of a large urban health plan; 80% of those determined to be eligible were enrolled and screened with ultrasound for fibroids ≥0.5 cm in diameter. African-American and white premenopausal participants who responded to at least one follow-up interview (N = 964, 85% of those eligible) constituted the study cohort. During follow-up (5822 person-years), participants self-reported any major uterine procedure (67% hysterectomies). Life-table analyses and Cox regression (with censoring for menopause) were used to estimate the risk of having a uterine procedure for women with no fibroids, small (diameter), medium (2-3.9 cm), and large fibroids (≥4 cm). Differences between African-American and white women, importance of a clinical diagnosis of fibroids prior to study enrollment, and the impact of submucosal fibroids on risk were investigated. PARTICIPANTS/MATERIALS, SETTING, METHODS: There was a greater loss to follow-up for African-Americans than whites (19 versus 11%). For those with follow-up data, 64% had fibroids at baseline, 33% of whom had had a prior diagnosis. Of those with fibroids, 27% had small fibroids (diameter), 46% had medium (largest fibroid 2-3.9 cm in diameter), and 27% had large fibroids (largest ≥4 cm in diameter). Twenty-one percent had at least one submucosal fibroid. MAIN RESULTS AND THE ROLE OF CHANCE: Major uterine procedures were reported by 115 women during follow-up. The estimated risk of having a procedure in any given year of follow-up for those with fibroids compared with those without fibroids increased markedly with fibroid-size category (from 4-fold, confidence interval (CI) (1.4-11.1) for the small fibroids to 10-fold, CI (4.4-24.8) for the medium fibroids, to 27-fold, CI (11.5-65.2) for the large fibroids). This influence of fibroid size on risk did not differ between African-Americans and whites (P-value for interaction = 0.88). Once fibroid size at enrollment was accounted for, having a prior diagnosis at the time of ultrasound screening was not predictive of having a procedure. Exclusion of women with a submucosal fibroid had little influence on the results. The 8-year risk of a procedure based on lifetable analyses was 2% for women with no fibroids, 8, 23, and 47%, respectively, for women who had small, medium or large fibroids at enrollment. Given the strong association of fibroid size with subsequent risk of a procedure, these findings are unlikely to be due to chance. LIMITATIONS, REASONS FOR CAUTION: Despite a large sample size, the number of women having procedures during follow-up was relatively small. Thus, covariates such as BMI, which were not important in our analyses, may have associations that were too small to detect with our sample size. Another limitation is that the medical procedures were self-reported. However, we attempted to retrieve medical records when participants agreed, and 77% of the total procedures reported were verified. Our findings are likely to be generalizable to other African-American and white premenopausal women in their late 30s and 40s, but other ethnic groups have not been studied. WIDER IMPLICATIONS OF THE FINDINGS: Though further studies are needed to confirm and extend the results, our findings provide an initial estimate of disease progression that will be helpful to clinicians and their patients. STUDY FUNDING/COMPETING INTERESTS: Funding came from the Intramural Research Program of the National Institute of Environmental Health Sciences and the Office of Research on Minority Health, National Institutes of Health, Health and Human Services (IRB #OH95-E-N048). The authors have no conflicts of interest. TRIAL REGISTRATION NUMBER: Not applicable

Implementing risk stratification to the treatment of adolescent substance use among youth involved in the juvenile justice system: protocol of a hybrid type I trial

BACKGROUND: Youth involved in the juvenile justice system (YIJJ) have high rates of substance use problems; however, rates of YIJJ engagement in substance use services is low. Barriers to service engagement include lack of appropriate screening and connection to services by the juvenile justice system, as well as lack of resources for delivering evidence-based treatment in community-based settings. To address these barriers, this paper describes a protocol for a type 1 hybrid design to (1) implement universal substance use screening for YIJJ; (2) implement and evaluate the feasibility and effectiveness of a brief, three-session substance use interventions based in motivational interviewing for youth with mild/moderate substance use: Teen Intervene (an individual-based intervention); (3) implement ENCOMPASS, an evidence-based substance use intervention based in motivational enhancement and cognitive behavioral therapy for youth with severe substance use; and (4) evaluate facilitators and barriers to implementing these interventions for mild to severe substance use among YIJJ in community mental health centers (CMHC). METHODS/DESIGN: Using a hybrid type 1 clinical effectiveness-implementation design, we will collaborate with CMHCs and juvenile justice in two rural Indiana counties. Guided by the EPIS (exploration, preparation, implementation, sustainability) framework, we will measure factors that affect implementation of substance use screening in juvenile justice and implementation of substance use interventions in CMHCs utilizing self-reports and qualitative interviews with juvenile justice and CMHC staff pre- and post-implementation. YIJJ with mild/moderate substance use will receive a brief interventions and YIJJ with severe substance use will receive ENCOMPASS. We will measure the effectiveness of a brief and comprehensive intervention by assessing changes in substance use across treatment. We anticipate recruiting 160 YIJJ and their caregivers into the study. We will assess intervention outcomes utilizing baseline, 3-, and 6-month assessments. DISCUSSION: Findings have the potential to improve screening and intervention services for YIJJ

Burnout and Mental Health Stigma among Juvenile Probation Officers: The Moderating Effect of Participatory Atmosphere

Despite high rates of mental health problems among juvenile justice-involved youth, mental health stigma among juvenile probation officers (JPOs) is under-studied. This cross-sectional study examined effects of job burnout and workplace participatory atmosphere on mental health stigma among JPOs across Indiana (n = 226). Participatory atmosphere moderated the relationship between JPO burnout-related cynicism and mental health stigma (interaction β = - 0.14, p = .04); burnout was related to greater mental health stigma at low levels of participatory atmosphere. Findings suggest participatory atmosphere mitigates effects of burnout on mental health stigma among JPOs. Organizational-level interventions might help to reduce mental health stigma and combat negative effects from burnout among JPOs

Critical statistics in a power-law random banded matrix ensemble

We investigate the statistical properties of the eigenvalues and eigenvectors in a random matrix ensemble with $H_{ij}\sim |i-j|^{-\mu}$. It is known that this model shows a localization-delocalization transition (LDT) as a function of the parameter $\mu$. The model is critical at $\mu=1$ and the eigenstates are multifractals. Based on numerical simulations we demonstrate that the spectral statistics at criticality differs from semi-Poisson statistics which is expected to be a general feature of systems exhibiting a LDT or `weak chaos'.Comment: 4 pages in PS including 5 figure

Observational measure of implementation progress in community based settings: The Stages of implementation completion (SIC)

<p>Abstract</p> <p>Background</p> <p>An increasingly large body of research is focused on designing and testing strategies to improve knowledge about how to embed evidence-based programs (EBP) into community settings. Development of strategies for overcoming barriers and increasing the effectiveness and pace of implementation is a high priority. Yet, there are few research tools that measure the implementation process itself. The Stages of Implementation Completion (SIC) is an observation-based measure that is used to track the time to achievement of key implementation milestones in an EBP being implemented in 51 counties in 53 sites (two counties have two sites) in two states in the United States.</p> <p>Methods</p> <p>The SIC was developed in the context of a randomized trial comparing the effectiveness of two implementation strategies: community development teams (experimental condition) and individualized implementation (control condition). Fifty-one counties were randomized to experimental or control conditions for implementation of multidimensional treatment foster care (MTFC), an alternative to group/residential care placement for children and adolescents. Progress through eight implementation stages was tracked by noting dates of completion of specific activities in each stage. Activities were tailored to the strategies for implementing the specific EBP.</p> <p>Results</p> <p>Preliminary data showed that several counties ceased progress during pre-implementation and that there was a high degree of variability among sites in the duration scores per stage and on the proportion of activities that were completed in each stage. Progress through activities and stages for three example counties is shown.</p> <p>Conclusions</p> <p>By assessing the attainment time of each stage and the proportion of activities completed, the SIC measure can be used to track and compare the effectiveness of various implementation strategies. Data from the SIC will provide sites with relevant information on the time and resources needed to implement MTFC during various phases of implementation. With some modifications, the SIC could be appropriate for use in evaluating implementation strategies in head-to-head randomized implementation trials and as a monitoring tool for rolling out other EBPs.</p