Solution of the two identical ion Penning trap final state

We have derived a closed form analytic expression for the asymptotic motion of a pair of identical ions in a high precision Penning trap. The analytic solution includes the effects of special relativity and the Coulomb interaction between the ions. The existence and physical relevance of such a final state is supported by a confluence of theoretical, experimental and numerical evidence.Comment: 5 pages and 2 figure

The Structure of Client Language and Drinking Outcomes in Project MATCH

Client language during Motivational Interviewing interventions is an important predictor of drinking outcomes, but there are inconsistencies in the literature regarding what aspects of client language are most predictive. We characterized the structure of client language by factor analyzing frequency counts of several categories of client speech. The results provide limited support for a model proposed by Miller et al. (2006) and Amrhein et al. (2003) but with some important differences. While Amrhein et al. (2003) found that only increasing strength in client commitment language predicted behavior change, the current study revealed that client language preparatory to commitment predicted drinking outcomes

Rheometry based on free surface velocity

This paper explores the possibility of identifying the rheology of a fluid by monitoring how the free surface velocity field is affected by a perturbation in the flow. The dam-break problem is considered which results from the release of a gate initially separating two fluid pools of different depth. The flow velocity is measured by seeding the free surface with buoyant particles and using Particle Tracking Velocimetry. In parallel, a mathematical model based on the lubrication approximation for fluids with a power-law rheology is developed. The model is validated against a similarity solution which is obtained for the spreading of a gravity current under its own weight and neglecting surface tension. Minimizing the difference between the free surface velocity fields obtained numerically and measured experimentally enables the identification of rheological parameters. The methodology is tested on ideal and noisy synthetic data sets and experimental data obtained with aqueous glycerol

Exploratory behavior is linked to stress physiology and social network centrality in free-living house finches (Haemorhous mexicanus)

Animal personality has been linked to individual variation in both stress physiology and social behaviors, but few studies have simultaneously examined covariation between personality traits, stress hormone levels, and behaviors in free-living animals. We investigated relationships between exploratory behavior (one aspect of animal personality), stress physiology, and social and foraging behaviors in wild house finches (Haemorhous mexicanus). We conducted novel environment assays after collecting samples of baseline and stress-induced plasma corticosterone concentrations from a subset of house finches. We then fitted individuals with Passive Integrated Transponder tags and monitored feeder use and social interactions at radio-frequency identification equipped bird feeders. First, we found that individuals with higher baseline corticosterone concentrations exhibit more exploratory behaviors in a novel environment. Second, more exploratory individuals interacted with more unique conspecifics in the wild, though this result was stronger for female than for male house finches. Third, individuals that were quick to begin exploring interacted more frequently with conspecifics than slow-exploring individuals. Finally, exploratory behaviors were unrelated to foraging behaviors, including the amount of time spent on bird feeders, a behavior previously shown to be predictive of acquiring a bacterial disease that causes annual epidemics in house finches. Overall, our results indicate that individual differences in exploratory behavior are linked to variation in both stress physiology and social network traits in free-living house finches. Such covariation has important implications for house finch ecology, as both traits can contribute to fitness in the wild

Factors Associated with Physical Activity Increases and Decreases Among a Sample of Appalachian Residents During the COVID-19 Pandemic: A Cross-Sectional Study

Introduction: Physical activity (PA) can prevent and reduce the deleterious physical and mental health effects of COVID-19 and associated lockdowns. Research conducted early in the pandemic demonstrates that a greater proportion of adults in the U.S. have decreased than increased PA, and the effects vary by sociodemographic factors. Ongoing evidence is important to identify patterns in PA changes during the pandemic. Purpose: This study aims to identify factors associated with increases and decreases in PA during the COVID-19 pandemic in a convenience sample of adults residing in Appalachia. Methods: Surveys were collected from a convenience sample of adults from eight counties in West Virginia from January to March 2021. Logistic regression analysis was used to identify sociodemographic, health, and rurality factors associated with (1) increased PA and (2) decreased PA during the pandemic, assessed retrospectively via self-report. Results: Analysis of 1,401 survey responses revealed that better self-rated health, lower body mass index, and higher income and education were associated with a greater likelihood of more time spent doing PA during the pandemic (p ≤ .05). Respondents with lower self-rated health, higher body mass index, lower income, and lower levels of education—plus females and those living in a more urban county—were more likely to spend less time doing PA during the pandemic (p ≤ .05). Implications: Analyses suggest that pre-pandemic disparities in PA by health, wealth, and education were exacerbated during the pandemic. These must be addressed before physical inactivity and ill health become endemic to the Appalachian Region

Thin-film flow of a Bingham fluid over topography with a temperature-dependent rheology

We consider the flow of a viscoplastic fluid on a horizontal or an inclined surface with a flat and an asymmetric topography. A particular application of interest is the spread of a fixed mass – a block – of material under its own weight. The rheology of the fluid is described by the Bingham model which includes the effect of yield stress, i.e. a threshold stress which must be exceeded before flow can occur. Both the plastic viscosity and the yield stress are modelled with temperature-dependent parameters. The flow is described by the lubrication approximation, and the heat transfer by a depthaveraged energy conservation equation. Results show that for large values of the yield stress, only the outer fraction of the fluid spreads outward, the inner fraction remaining unyielded. We also present an analysis which predicts the threshold value of the yield stress for which partial slump occurs

A crack in the facade? Situating Singapore in global flows of electronic waste

Singapore is alleged to be a key node in global flows of e‐waste prohibited under the Basel Convention. We combine a close reading of the Convention and related documents with findings from nonparticipant observation of and interviews with Singapore‐based traders of discarded electronics. The case offers both important conceptual and empirical findings for future studies of territory in market‐making activity. Conceptually, our research suggests that it may be analytically useful in such studies to conceptualize territory without presupposing that it is generated as a result of separate domains or logics such as ‘the political’ or ‘the economic’. Empirically, we find that the regulatory framework of the Convention, combined with the action of traders based in Singapore, generates a territorialization of the city‐state such that it operates as a crack in the regulatory edifice of the Convention, even as Singapore lawfully fulfils its obligations to it. Moreover, allegations premised on the role of Singapore as a facilitator of global e‐waste dumping misrepresent its crucial role as a conduit of electronic equipment for the significant reuse markets elsewhere in Southeast Asia and beyond. The case indicates that the allegations against Singapore hinge on the city‐state being territorialized as a ‘developing country’

Clinician acquisition and retention of Motivational Interviewing skills: a two-and-a-half-year exploratory study

<p>Abstract</p> <p>Background</p> <p>Motivational interviewing (MI) is a collaborative, client-centred counselling style aimed at eliciting and strengthening clients' intrinsic motivation to change. There is strong research evidence supporting the efficacy of MI, notably in its application among alcohol and drug abuse populations. MI interventions in smoking cessation may yield modest but significant increases in quitting. The present study sought to assess the acquisition and retention of MI skills in counsellors at the Swedish National Tobacco Quitline.</p> <p>Methods</p> <p>Three audio-recorded sessions from each of three counsellors were assessed using the Motivational Interviewing Treatment Integrity (MITI) Code Version 3.0 over 11 assessment periods at fixed intervals in a two-and-a-half year period during which counsellors received ongoing supervision.</p> <p>Results</p> <p>The mean skill for all counsellors improved throughout the study period in most MITI variables. However, great variations in MI skill between counsellors were observed, as well as fluctuations in performance in counsellors over time.</p> <p>Conclusion</p> <p>The present exploratory study covers a longer time period than most evaluations of MI training, and has several advantages with regard to study design. It may provide a basis for (larger sample) replication to test MI skill (as measured by the MITI) in relation to behaviour change in clients, to evaluate MI training, and to assess the acquisition and retention of MI skill over time. Difficulties in acquiring and retaining MI skill may raise the issue of a selection policy for MI training. Moreover, fluctuations in MI skill over time emphasise the greater importance of continuous feedback and supervision over initial MI training, and the need for the use of validated treatment integrity assessment instruments in ordinary clinical implementations of MI.</p