Design and Implementation of the Larch/C++ Type System

This paper describes the design of a type system for the Larch/C++ specification language. To motivate the features of the type system, the type systems of both the Larch Shared Language and C++ are described. After this background, an informal description of the Larch/C++ type system is followed by a formal presentation of the type rules. The implementation of an infrastructure for the type system is then described

Efficient stochastic thermostatting of path integral molecular dynamics

The path integral molecular dynamics (PIMD) method provides a convenient way to compute the quantum mechanical structural and thermodynamic properties of condensed phase systems at the expense of introducing an additional set of high-frequency normal modes on top of the physical vibrations of the system. Efficiently sampling such a wide range of frequencies provides a considerable thermostatting challenge. Here we introduce a simple stochastic path integral Langevin equation (PILE) thermostat which exploits an analytic knowledge of the free path integral normal mode frequencies. We also apply a recently-developed colored-noise thermostat based on a generalized Langevin equation (GLE), which automatically achieves a similar, frequency-optimized sampling. The sampling efficiencies of these thermostats are compared with that of the more conventional Nos\'e-Hoover chain (NHC) thermostat for a number of physically relevant properties of the liquid water and hydrogen-in-palladium systems. In nearly every case, the new PILE thermostat is found to perform just as well as the NHC thermostat while allowing for a computationally more efficient implementation. The GLE thermostat also proves to be very robust delivering a near-optimum sampling efficiency in all of the cases considered. We suspect that these simple stochastic thermostats will therefore find useful application in many future PIMD simulations.Comment: Accepted for publication on JC

Quantum fluctuations can promote or inhibit glass formation

The very nature of glass is somewhat mysterious: while relaxation times in glasses are of sufficient magnitude that large-scale motion on the atomic level is essentially as slow as it is in the crystalline state, the structure of glass appears barely different than that of the liquid that produced it. Quantum mechanical systems ranging from electron liquids to superfluid helium appear to form glasses, but as yet no unifying framework exists connecting classical and quantum regimes of vitrification. Here we develop new insights from theory and simulation into the quantum glass transition that surprisingly reveal distinct regions where quantum fluctuations can either promote or inhibit glass formation.Comment: Accepted for publication in Nature Physics. 22 pages, 3 figures, 1 Tabl

Theory and simulations of quantum glass forming liquids

A comprehensive microscopic dynamical theory is presented for the description of quantum fluids as they transform into glasses. The theory is based on a quantum extension of mode-coupling theory. Novel effects are predicted, such as reentrant behavior of dynamical relaxation times. These predictions are supported by path integral ring polymer molecular dynamics simulations. The simulations provide detailed insight into the factors that govern slow dynamics in glassy quantum fluids. Connection to other recent work on both quantum glasses as well as quantum optimization problems is presented.Comment: 11 pages, 5 figures, 1 Tabl

A randomized controlled trial to evaluate self-determination theory for exercise adherence and weight control: rationale and intervention description

<p>Abstract</p> <p>Background</p> <p>Research on the motivational model proposed by Self-Determination Theory (SDT) provides theoretically sound insights into reasons why people adopt and maintain exercise and other health behaviors, and allows for a meaningful analysis of the motivational processes involved in behavioral self-regulation. Although obesity is notoriously difficult to reverse and its recidivism is high, adopting and maintaining a physically active lifestyle is arguably the most effective strategy to counteract it in the long-term. The purposes of this study are twofold: i) to describe a 3-year randomized controlled trial (RCT) aimed at testing a novel obesity treatment program based on SDT, and ii) to present the rationale behind SDT's utility in facilitating and explaining health behavior change, especially physical activity/exercise, during obesity treatment.</p> <p>Methods</p> <p>Study design, recruitment, inclusion criteria, measurements, and a detailed description of the intervention (general format, goals for the participants, intervention curriculum, and main SDT strategies) are presented. The intervention consists of a 1-year group behavioral program for overweight and moderately obese women, aged 25 to 50 (and pre-menopausal), recruited from the community at large through media advertisement. Participants in the intervention group meet weekly or bi-weekly with a multidisciplinary intervention team (30 2 h sessions in total), and go through a program covering most topics considered critical for successful weight control. These topics and especially their delivery were adapted to comply with SDT and Motivational Interviewing guidelines. Comparison group receive a general health education curriculum. After the program, all subjects are follow-up for a period of 2 years.</p> <p>Discussion</p> <p>Results from this RCT will contribute to a better understanding of how motivational characteristics, particularly those related to physical activity/exercise behavioral self-regulation, influence treatment success, while exploring the utility of Self-Determination Theory for promoting health behavior change in the context of obesity.</p> <p>Trial Registration</p> <p><b>Clinical Trials Gov. Identifier </b>NCT00513084</p

Immunochip analysis identifies multiple susceptibility loci for systemic sclerosis

In this study, 1,833 systemic sclerosis (SSc) cases and 3,466 controls were genotyped with the Immunochip array. Classical alleles, amino acid residues, and SNPs across the human leukocyte antigen (HLA) region were imputed and tested. These analyses resulted in a model composed of six polymorphic amino acid positions and seven SNPs that explained the observed significant associations in the region. In addition, a replication step comprising 4,017 SSc cases and 5,935 controls was carried out for several selected non-HLA variants, reaching a total of 5,850 cases and 9,401 controls of European ancestry. Following this strategy, we identified and validated three SSc risk loci, including DNASE1L3 at 3p14, the SCHIP1-IL12A locus at 3q25, and ATG5 at 6q21, as well as a suggested association of the TREH-DDX6 locus at 11q23. The associations of several previously reported SSc risk loci were validated and further refined, and the observed peak of association in PXK was related to DNASE1L3. Our study has increased the number of known genetic associations with SSc, provided further insight into the pleiotropic effects of shared autoimmune risk factors, and highlighted the power of dense mapping for detecting previously overlooked susceptibility loci

The Impact of Nocturia on Mortality: A Systematic Review and Meta-Analysis

Purpose: Nocturia (waking from sleep at night to void) is a common cause of sleep disruption associated with increased comorbidity and impaired quality of life. However, its impact on mortality remains unclear. We performed a systematic review and meta-analysis to evaluate the association of nocturia with mortality as a prognostic factor and a causal risk factor. Materials and Methods: We searched PubMed (R), Scopus (R), CINAHL (R) (Cumulative Index of Nursing and Allied Health Literature) and major conference abstracts up to December 31, 2018. Random effects meta-analyses were done to address the adjusted RR of mortality in people with nocturia. Metaregression was performed to explore potential determinants of heterogeneity, including the risk of bias. We applied the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) framework to rate the quality of evidence for nocturia as a prognostic risk factor for mortality and separately as a cause of mortality. Results: Of the 5,230 identified reports 11 observational studies proved eligible for inclusion. To assess nocturia 10 studies used symptom questionnaires and 1 used frequency-volume charts. Nocturia was defined as 2 or more episodes per night in 6 studies (55%) and as 3 or more episodes per night in 5 (45%). Pooled estimates demonstrated a RR of 1.27 (95% CI 1.16-1.40, I-2=48%) with an absolute 1.6% and 4.0% 5-year mortality difference in individuals 60 and 75 years old, respectively. The pooled estimates of relative risk did not differ significantly across varying age, gender, followup, nocturia case definition, risk of bias or study region. We rated the quality of evidence for nocturia as a prognostic factor as moderate and as a cause of mortality as very low. Conclusions: Nocturia is probably associated with an approximately 1.3-fold increased risk of death.Peer reviewe

Self-regulation and self-control in exercise: The strength-energy model

Self-regulation is an important component of psychosocial theories of exercise behaviour and lack of self-regulatory skills are associated with low adherence to health-related exercise. This review presents a strength-energy model of self-control as an explanation of self-regulation in exercise contexts. The review will provide impetus for original research aimed at understanding exercise behaviour and help develop recommendations for exercise promotion. In the model, self-control is conceptualized as a global but limited resource. Engaging in actions requiring self-control depletes resources leading to self-regulatory failure. Self-control resource depletion is reduced through rest and frequent training on self-control. The expectation of the need to exert self-control in future leads to a conservation of self-control resources. Proposed mechanisms for self-control resource depletion include changes in physiological markers and blood glucose levels. Based on our review, we propose an integrated model of self-regulation incorporating hypotheses from the strength-energy model with those from traditional psychosocial models of exercise behaviour. Recommendations for future research include incorporating hypotheses from the strength-energy model into theories of self-presentation and interpersonal relations in exercise. Practical recommendations aimed at minimising self-control depletion in exercise include the provision of advice on nutrition and recovery, self-control training and motivational and implementation intention strategies

Controlling anal incontinence in women by performing anal exercises with biofeedback or loperamide (CAPABLe) trial: Design and methods

The goals of this trial are to determine the efficacy and safety of two treatments for women experiencing fecal incontinence. First, we aim to compare the use of loperamide to placebo and second, to compare the use of anal sphincter exercises with biofeedback to usual care. The primary outcome is the change from baseline in the St. Mark's (Vaizey) Score 24 weeks after treatment initiation. As a Pelvic Floor Disorders Network (PFDN) trial, subjects are enrolling from eight PFDN clinical centers across the United States. A centralized data coordinating center supervises data collection and analysis. These two first-line treatments for fecal incontinence are being investigated simultaneously using a two-by-two randomized factorial design: a medication intervention (loperamide versus placebo) and a pelvic floor strength and sensory training intervention (anal sphincter exercises with manometry-assisted biofeedback versus usual care using an educational pamphlet). Interventionists providing the anal sphincter exercise training with biofeedback have received standardized training and assessment. Symptom severity, diary, standardized anorectal manometry and health-related quality of life outcomes are assessed using validated instruments administered by researchers masked to randomized interventions. Cost effectiveness analyses will be performed using prospectively collected data on care costs and resource utilization. This article describes the rationale and design of this randomized trial, focusing on specific research concepts of interest to researchers in the field of female pelvic floor disorders and all other providers who care for patients with fecal incontinence