2,030 research outputs found

    The Jones polynomial of an almost alternating link

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    A link is almost alternating if it is non-alternating and has a diagram that can be transformed into an alternating diagram via one crossing change. We give formulas for the first two and last two potential coefficients of the Jones polynomial of an almost alternating link. Using these formulas, we show that the Jones polynomial of an almost alternating link is nontrivial. We also show that either the first two or last two coefficients of the Jones polynomial of an almost alternating link alternate in sign. Finally, we describe conditions that ensure an almost alternating diagram has the fewest number of crossings among all almost alternating diagrams of the link.Comment: 24 pages, 16 figures; minor changes throughou

    Engagement in a Community-Based Integral Practice Program Enhances Well-being

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    This project examined associations between engagement in a community-based integral practice program and measures of health and well-being. In this prospective withinsubjects uncontrolled cohort study, 53 participants of Integral Transformative Practice (ITP), a program that incorporates movement, nutritional and exercise recommendations, affirmations, contemplative introspection, theory and philosophy, and group discussions and activities, were followed over one year. Participants completed online questionnaires upon enrollment, at six months, and one year later. Repeated measures analyses showed that participants reported improved overall health and reduced symptoms of ill health, as well as increased psychological well-being, vitality, and quality of life over the course of the year. Greater involvement in the practice community predicted better psychological well-being, increased quality of life, and greater self-transcendence. Self-transcendence mediated the relationship between level of ITP involvement and psychological well-being outcomes, and predicted physical health outcomes, suggesting that this construct may be important to the effectiveness of participating in wellness interventions

    Strongly Bound Surface Water Affects the Shape Evolution of Cerium Oxide Nanoparticles

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    The surface structure and composition of functional materials are well-known to be critically important factors controlling the surface reactivity. However, when doped the surface composition will change, and the challenge is to identify its impact on important surface processes and nanoparticle morphologies. We have begun to address this by using a combination of density functional theory and potential-based methods to investigate the effect of surface dopants on water adsorption and morphology of the technologically important material, CeO2_2, which finds application as electrolyte in SOFCs, catalyst in soot combustion, and enzyme mimetic agents in biomedicine. We show that by mapping CeO2_2 surface phase diagrams we can predict nanoparticle morphologies as a function of dopant, temperature, and water partial pressure. Our results show that low-temperature, undoped CeO2_2 nanocubes with active {100} surface sites are thermodynamically stable, but at the typical high temperature, operating conditions favor polyhedra where {100} surfaces are replaced by less active {111} surfaces by surface ion migration. However, doping with trivalent cations, such as Gd3+^{3+}, will increase binding of water on the {100} surfaces and hence act to preserve the cuboidal architecture by capping the active surfaces. As surfaces tend to be decorated by impurities and dopants it is clear that their role should receive more attention and the approach we describe can be routinely applied to nanomaterials, morphologies, and associated active/inactive surfaces

    A process evaluation, with mediation analysis, of a web-based intervention to augment primary care exercise referral schemes:the e-coachER randomised controlled trial

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    BACKGROUND: The e-coachER trial aimed to determine whether adding web-based behavioural support to exercise referral schemes (ERS) increased long-term device-measured physical activity (PA) for patients with chronic conditions, compared to ERS alone, within a randomised controlled trial. This study explores the mechanisms of action of the e-coachER intervention using measures of the behaviour change processes integral to the intervention's logic model.METHODS: Four hundred fifty adults with obesity, diabetes, hypertension, osteoarthritis or history of depression referred to an ERS were recruited in Plymouth, Birmingham and Glasgow. The e-coachER intervention comprising 7-Steps to Health was aligned with Self-Determination Theory and mapped against evidence-based behaviour change techniques (BCTs). Participants completed questionnaires at 0, 4, and 12 months to assess PA and self-reported offline engagement with core BCTs in day-to-day life (including action planning and self-monitoring) and beliefs relating to PA (including perceived importance, confidence, competence, autonomy and support). We compared groups at 4 and 12 months, controlling for baseline measures and other covariates. Mediation analysis using the product of coefficients method was used to determine if changes in process variables mediated intervention effects on moderate to vigorous physical activity (MVPA) recorded by accelerometer and self-report at 4- and 12-months.RESULTS: The internal reliability (Cronbach's alpha) for all multi-item scales was &gt; 0.77. At 4-months, those randomised to e-coachER reported higher levels of PA beliefs relating to importance (1.01, 95% confidence interval (CI): 0.42 to 1.61, p = 0.001), confidence (1.28, 95% CI: 0.57 to 1.98, p &lt; 0.001), competence (1.61, 95% CI: .68 to 2.54, p = 0.001), availability of support (0.77, 95% CI: 0.07 to 1.48, p = 0.031), use of action planning (1.54, 95% CI: 0.23 to 2.85, p = 0.021) and use of self-monitoring (0.76, 95% CI: 0.19 to 1.32, p = 0.009) compared to ERS alone. There were no intervention effects on autonomous beliefs or perceived frequency of support, compared to ERS alone. At the 12-month follow-up, participants belief in the importance of PA was the only process measure to remain significantly higher in the e-coachER group when compared to ERS alone (0.75, 95% CI: 0.05 to 1.45). Intervention effects on perceived importance (2.52, 95% CI: 0.45 to 5.39), action planning (1.56, 95% CI: 0.10 to 3.54) and self-monitoring (1.92, 95% CI: 0.21 to 4.33) at 4-months significantly mediated change in accelerometer measured MVPA at 12-months (recorded in ≥ 10-min bouts).CONCLUSIONS: e-coachER led to some short-term changes in most process outcomes. Some of these processes also appeared to mediate e-coachER effects on changes in accelerometer measured MVPA. Further work should be carried out to understand how best to design and implement theoretically underpinned web-based physical activity promotion interventions within ERS.TRIAL REGISTRATION: ISRCTN, ISRCTN15644451 . Registered 12 February 2015.</p

    Early and Late Reoperation Rates With Various MIS Techniques for Adult Spinal Deformity Correction.

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    Study designA multicenter retrospective review of an adult spinal deformity database.ObjectiveWe aimed to characterize reoperation rates and etiologies of adult spinal deformity surgery with circumferential minimally invasive surgery (cMIS) and hybrid (HYB) techniques.MethodsInclusion criteria were age ≥18 years, and one of the following: coronal Cobb &gt;20°, sagittal vertical axis &gt;5 cm, pelvic tilt &gt;20°, and pelvic incidence-lumbar lordosis &gt;10°. Patients with either cMIS or HYB surgery, ≥3 spinal levels treated with 2-year minimum follow-up were included.ResultsA total of 133 patients met inclusion for this study (65 HYB and 68 cMIS). Junctional failure (13.8%) was the most common reason for reoperation in the HYB group, while fixation failure was the most common reason in the cMIS group (14.7%). There was a higher incidence of proximal junctional failure (PJF) than distal junctional failure (DJF) within HYB (12.3% vs 3.1%), but no significant differences in PJF or DJF rates when compared to cMIS. Early (&lt;30 days) reoperations were less common (cMIS = 1.5%; HYB = 6.1%) than late (&gt;30 days) reoperations (cMIS = 26.5%; HYB = 27.7%), but early reoperations were more common in the HYB group after propensity matching, largely due to infection rates (10.8% vs 0%, P = .04).ConclusionsAdult spinal deformity correction with cMIS and HYB techniques result in overall reoperation rates of 27.9% and 33.8%, respectively, at minimum 2-year follow-up. Junctional failures are more common after HYB approaches, while pseudarthrosis/fixation failures happen more often with cMIS techniques. Early reoperations were less common than later returns to the operating room in both groups, but cMIS demonstrated less risk of infection and early reoperation when compared with the HYB group

    Adding web-based support to exercise referral schemes improves symptoms of depression in people with elevated depressive symptoms:A secondary analysis of the e-coachER randomised controlled trial

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    Background: Exercise referral schemes (ERS) reduce depression but the additional effect on mental health from web-based behavioural support is unknown. The e-coachER trial reported no effect of augmenting usual ERS with theory-driven web-based behavioural support on moderate to vigorous physical activity (MVPA) at 12 months for patients with chronic physical and mental health conditions. The present study reports the effects of the e-coachER intervention on depression, anxiety and MVPA only among participants with elevated depressive symptoms and investigates whether these were mediated by changes in MVPA and hypothesised cognitive and behavioural processes. Methods: Of the original 450 adults recruited into the e-coachER trial, 205 had at least mild depression, based on the Hospital Anxiety and Depression Scale (HADS), and were included in the present analysis. Data collected included the HADS, accelerometer measured and self-reported MVPA and survey process measures on physical activity action planning, self-monitoring and goal reviewing, and perceived importance, confidence, competence, autonomy and support. Linear mixed models were used to compare groups for change in depression and anxiety at 4 and 12 months using intention-to-treat complete case analysis, controlling for baseline. We also examined whether changes in physical activity and process variables at 4 months mediated changes in depression and anxiety at 12 months. Results: Of the 205 participants, 138 (67%) provided follow-up data at four months and 126 (61%) at 12 months. For those that provided follow-up data, those randomised to e-coachER reported improved levels of depression (−1.36, 95% CI: −2.55 to −0.18) but not anxiety, or MVPA, compared with controls at four months. No differences were observed at 12 months for depression, anxiety or MVPA. Intervention effects on accelerometer-measured or self-reported MVPA did not mediate improvements in depression or anxiety. However, intervention effects on confidence, competence and self-monitoring at four months significantly mediated the reduction in depression scores at four months. Intervention effects on competence and self-monitoring at four months also significantly mediated improvements in anxiety scores at four months. Interpretation: Adding web-based support to usual ERS leads to reductions in depression but not anxiety at four months. Changes in depression and anxiety were influenced by changing people's motivational regulations toward physical activity. The benefit of adding web-based support to usual ERS on mental health appears to be from increasing a sense of confidence, competence and self-monitoring rather than from increasing physical activity in people with elevated depression. ERS should focus more on strengthening motivational regulations than just doing more exercise. Trial registration: ISRCTN15644451.</p

    Adding web-based support to exercise referral schemes improves symptoms of depression in people with elevated depressive symptoms:A secondary analysis of the e-coachER randomised controlled trial

    Get PDF
    Background: Exercise referral schemes (ERS) reduce depression but the additional effect on mental health from web-based behavioural support is unknown. The e-coachER trial reported no effect of augmenting usual ERS with theory-driven web-based behavioural support on moderate to vigorous physical activity (MVPA) at 12 months for patients with chronic physical and mental health conditions. The present study reports the effects of the e-coachER intervention on depression, anxiety and MVPA only among participants with elevated depressive symptoms and investigates whether these were mediated by changes in MVPA and hypothesised cognitive and behavioural processes. Methods: Of the original 450 adults recruited into the e-coachER trial, 205 had at least mild depression, based on the Hospital Anxiety and Depression Scale (HADS), and were included in the present analysis. Data collected included the HADS, accelerometer measured and self-reported MVPA and survey process measures on physical activity action planning, self-monitoring and goal reviewing, and perceived importance, confidence, competence, autonomy and support. Linear mixed models were used to compare groups for change in depression and anxiety at 4 and 12 months using intention-to-treat complete case analysis, controlling for baseline. We also examined whether changes in physical activity and process variables at 4 months mediated changes in depression and anxiety at 12 months. Results: Of the 205 participants, 138 (67%) provided follow-up data at four months and 126 (61%) at 12 months. For those that provided follow-up data, those randomised to e-coachER reported improved levels of depression (−1.36, 95% CI: −2.55 to −0.18) but not anxiety, or MVPA, compared with controls at four months. No differences were observed at 12 months for depression, anxiety or MVPA. Intervention effects on accelerometer-measured or self-reported MVPA did not mediate improvements in depression or anxiety. However, intervention effects on confidence, competence and self-monitoring at four months significantly mediated the reduction in depression scores at four months. Intervention effects on competence and self-monitoring at four months also significantly mediated improvements in anxiety scores at four months. Interpretation: Adding web-based support to usual ERS leads to reductions in depression but not anxiety at four months. Changes in depression and anxiety were influenced by changing people's motivational regulations toward physical activity. The benefit of adding web-based support to usual ERS on mental health appears to be from increasing a sense of confidence, competence and self-monitoring rather than from increasing physical activity in people with elevated depression. ERS should focus more on strengthening motivational regulations than just doing more exercise. Trial registration: ISRCTN15644451.</p

    Hand controller commonality evaluation process

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    Hand controller selection for NASA's Orbiter and Space Station Freedom is an important area of human-telerobot interface design and evaluation. These input devices will control remotely operated systems that include large crane-like manipulators (e.g., Remote Manipulator System or RMS), smaller, more dexterous manipulators (e.g., Flight Telerobotic Servicer or FTS), and free flyers (e.g., Orbital Maneuvering Vehicle or OMV). Candidate hand controller configurations for these systems vary in many ways: shape, size, number of degrees-of-freedom (DOF), operating modes, provision of force reflection, range of movement, and 'naturalness' of use. Unresolved design implementation issues remain, including such topics as how the current Orbiter RMS rotational and translational rate hand controllers compare with the proposed Space Station Freedom hand controllers, the advantages that position hand controllers offer for these applications, and whether separate hand controller configurations are required for each application. Since previous studies contain little empirical hand controller task performance data, a controlled study is needed that tests Space Station Freedom candidate hand controllers during representative tasks. This study also needs to include anthropometric and biomechanical considerations

    The Democratic Biopolitics of PrEP

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    PrEP (Pre-Exposure Prophylaxis) is a relatively new drug-based HIV prevention technique and an important means to lower the HIV risk of gay men who are especially vulnerable to HIV. From the perspective of biopolitics, PrEP inscribes itself in a larger trend of medicalization and the rise of pharmapower. This article reconstructs and evaluates contemporary literature on biopolitical theory as it applies to PrEP, by bringing it in a dialogue with a mapping of the political debate on PrEP. As PrEP changes sexual norms and subjectification, for example condom use and its meaning for gay subjectivity, it is highly contested. The article shows that the debate on PrEP can be best described with the concepts ‘sexual-somatic ethics’ and ‘democratic biopolitics’, which I develop based on the biopolitical approach of Nikolas Rose and Paul Rabinow. In contrast, interpretations of PrEP which are following governmentality studies or Italian Theory amount to either farfetched or trivial positions on PrEP, when seen in light of the political debate. Furthermore, the article is a contribution to the scholarship on gay subjectivity, highlighting how homophobia and homonormativity haunts gay sex even in liberal environments, and how PrEP can serve as an entry point for the destigmatization of gay sexuality and transformation of gay subjectivity. ‘Biopolitical democratization’ entails making explicit how medical technology and health care relates to sexual subjectification and ethics, to strengthen the voice of (potential) PrEP users in health politics, and to renegotiate the profit and power of Big Pharma
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