3,235 research outputs found

    Search for domain wall dark matter with atomic clocks on board global positioning system satellites

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    Cosmological observations indicate that 85% of all matter in the Universe is dark matter (DM), yet its microscopic composition remains a mystery. One hypothesis is that DM arises from ultralight quantum fields that form macroscopic objects such as topological defects. Here we use GPS as a ~ 50,000 km aperture DM detector to search for such defects in the form of domain walls. GPS navigation relies on precision timing signals furnished by atomic clocks hosted on board GPS satellites. As the Earth moves through the galactic DM halo, interactions with topological defects could cause atomic clock glitches that propagate through the GPS satellite constellation at galactic velocities ~ 300 km/s. Mining 16 years of archival GPS data, we find no evidence for DM in the form of domain walls at our current sensitivity level. This allows us to improve the limits on certain quadratic scalar couplings of domain wall DM to standard model particles by several orders of magnitude.Comment: 7 pages (main text), and 12 pages for Supplementary Information. v3: Update titl

    Immunophoretic rapid diagnostic tests as a source of immunoglobulins for estimating malaria sero-prevalence and transmission intensity

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    RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.Abstract Background Sero-epidemiological methods are being developed as a tool for rapid assessment of malaria transmission intensity. Simple blood collection methods for use in field settings will make this more feasible. This paper describes validation of such a method, by analysing immunoglobulins from blood retained within immunophoretic rapid diagnostic tests (RDTs) for Plasmodium falciparum. RDTs are now widely used for the diagnosis of malaria and estimation of parasite rates, and this method represents a further use for these devices in malaria control. Methods Immunoglobulins eluted from RDTs, designed to detect parasite histidine rich protein-2 (HRP-2), were analysed by indirect ELISA for IgG recognizing the P. falciparum blood stage antigens merozoite surface protein-119 (MSP-119) and apical membrane antigen-1 (AMA-1). Optimal storage conditions for RDTs were evaluated by comparing antibody responses from RDTs stored in dry or humid conditions at 4°C or at ambient temperature (with or without air-conditioning) for 7, 31 or 70 days. Antibody levels estimated using 3,700 RDT samples from attendees at health facilities in North-eastern Tanzania were compared with contemporaneously collected filter paper blood spots (FPBS) and used to estimate seroconversion rates. Results Storage of RDTs at 4°C was optimal for immunoglobulin recovery but short-term storage at ambient temperatures did not substantially affect anti-malarial IgG levels. Results from RDTs were comparable with those from FPBSs, for both antigens. RDT-generated titres tended to be slightly higher than those generated from FPBSs, possibly due to greater recovery of immunoglobulins from RDTs compared to filter paper. Importantly, however, RDT-based seroconversion rates, and hence serological estimates of malaria transmission intensity, agreed closely with those from FPBSs. Conclusion RDTs represent a practical option for collecting blood for sero-epidemiological surveys, with potential cost and logistical advantages over filter paper and other blood collection methods. RDT-based seroepidemiology can be incorporated into routine monitoring of malaria endemicity, providing information to supplement parasite prevalence rates and generating rapid, robust assessment of malaria transmission intensity at minimal extra cost.Published versio

    Novel synthesis of O(6)-alkylguanine containing oligodeoxyribonucleotides as substrates for the human DNA repair protein, O(6)-methylguanine DNA methyltransferase (MGMT)

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    The human DNA repair protein O(6)-methylguanine DNA methyltransferase (MGMT) dealkylates mutagenic O(6)-alkylguanine lesions within DNA in an irreversible reaction which results in inactivation of the protein. MGMT also provides resistance of tumours to alkylating agents used in cancer chemotherapy and its inactivation is therefore of particular clinical importance. We describe a post-DNA synthesis strategy which exploits the novel, modified base 2-amino-6-methylsulfonylpurine and allows access for the first time to a wide variety of oligodeoxyribonucleotides (ODNs) containing O(6)-alkylguanines. One such ODN containing O(6)-(4-bromothenyl)guanine is the most potent inactivator described to date with an IC(50) of 0.1 nM

    Self-Determination Theory Applied to Health Contexts: A Meta-Analysis \ud

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    Behavior change is more effective and lasting when patients are autonomously motivated. To examine this idea, we identified 184 independent data sets from studies that utilized self-determination theory (SDT; Deci & Ryan, 2000) in health care and health promotion contexts. A meta-analysis evaluated relations between the SDT-based constructs of practitioner support for patient autonomy and patients’ experience of psychological need satisfaction, as well as relations between these SDT constructs and indices of mental and physical health. Results showed the expected relations among the SDT variables, as well as positive relations of psychological need satisfaction and autonomous motivation to beneficial health outcomes. Several variables (e.g., participants’ age, study design) were tested as potential moderators when effect sizes were heterogeneous. Finally, we used path analyses of the meta-analyzed correlations to test the interrelations among the SDT variables. Results suggested that SDT is a viable conceptual framework to study antecedents and outcomes of motivation for health-related behaviors

    An ALMA Survey of H₂CO in Protoplanetary Disks

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    H₂CO is one of the most abundant organic molecules in protoplanetary disks and can serve as a precursor to more complex organic chemistry. We present an Atacama Large Millimeter/submillimeter Array survey of H₂CO toward 15 disks covering a range of stellar spectral types, stellar ages, and dust continuum morphologies. H₂CO is detected toward 13 disks and tentatively detected toward a fourteenth. We find both centrally peaked and centrally depressed emission morphologies, and half of the disks show ring-like structures at or beyond expected CO snowline locations. Together these morphologies suggest that H₂CO in disks is commonly produced through both gas-phase and CO-ice-regulated grain-surface chemistry. We extract disk-averaged and azimuthally-averaged H₂CO excitation temperatures and column densities for four disks with multiple H₂CO line detections. The temperatures are between 20–50 K, with the exception of colder temperatures in the DM Tau disk. These temperatures suggest that H₂CO emission in disks generally emerges from the warm molecular layer, with some contributions from the colder midplane. Applying the same H₂CO excitation temperatures to all disks in the survey, we find that H₂CO column densities span almost three orders of magnitude (~5 × 10¹¹–5 × 10¹⁴ cm⁻²). The column densities appear uncorrelated with disk size and stellar age, but Herbig Ae disks may have less H₂CO compared to T Tauri disks, possibly because of less CO freeze-out. More H₂CO observations toward Herbig Ae disks are needed to confirm this tentative trend, and to better constrain under which disk conditions H₂CO and other oxygen-bearing organics efficiently form during planet formation

    Yoga as a complementary treatment for smoking cessation: rationale, study design and participant characteristics of the Quitting-in-Balance study

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    <p>Abstract</p> <p>Background</p> <p>Tobacco smoking remains the leading preventable cause of death among American women. Exercise has shown promise as an aid to smoking cessation because it reduces weight gain and weight concerns, improves affect, and reduces nicotine withdrawal symptoms and cigarette craving. Studies have shown that the practice of yoga improves weight control, and reduces perceived stress and negative affect. Yoga practice also includes regulation of breathing and focused attention, both of which may enhance stress reduction and improve mood and well-being and may improve cessation outcomes.</p> <p>Methods/Design</p> <p>This pilot efficacy study is designed to examine the rates of cessation among women randomized to either a novel, 8-week Yoga plus Cognitive Behavioral Therapy (CBT) smoking cessation intervention versus a Wellness program plus the same CBT smoking cessation intervention. Outcome measures include 7-day point prevalence abstinence at end of treatment, 3 and 6 months follow up and potential mediating variables (e.g., confidence in quitting smoking, self-efficacy). Other assessments include measures of mindfulness, spirituality, depressive symptoms, anxiety and perceived health (SF-36).</p> <p>Discussion</p> <p>Innovative treatments are needed that address barriers to successful smoking cessation among men and women. The design chosen for this study will allow us to explore potential mediators of intervention efficacy so that we may better understand the mechanism(s) by which yoga may act as an effective complementary treatment for smoking cessation. If shown to be effective, yoga can offer an alternative to traditional exercise for reducing negative symptoms that often accompany smoking cessation and predict relapse to smoking among recent quitters.</p> <p>Trial Registration</p> <p>ClinicalTrials NCT00492310</p

    Communication style and exercise compliance in physiotherapy (CONNECT). A cluster randomized controlled trial to test a theory-based intervention to increase chronic low back pain patients’ adherence to physiotherapists’ recommendations: study rationale, design, and methods

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    Physical activity and exercise therapy are among the accepted clinical rehabilitation guidelines and are recommended self-management strategies for chronic low back pain. However, many back pain sufferers do not adhere to their physiotherapist’s recommendations. Poor patient adherence may decrease the effectiveness of advice and home-based rehabilitation exercises. According to self-determination theory, support from health care practitioners can promote patients’ autonomous motivation and greater long-term behavioral persistence (e.g., adherence to physiotherapists’ recommendations). The aim of this trial is to assess the effect of an intervention designed to increase physiotherapists’ autonomy-supportive communication on low back pain patients’ adherence to physical activity and exercise therapy recommendations. \ud \ud This study will be a single-blinded cluster randomized controlled trial. Outpatient physiotherapy centers (N =12) in Dublin, Ireland (population = 1.25 million) will be randomly assigned using a computer-generated algorithm to either the experimental or control arm. Physiotherapists in the experimental arm (two hospitals and four primary care clinics) will attend eight hours of communication skills training. Training will include handouts, workbooks, video examples, role-play, and discussion designed to teach physiotherapists how to communicate in a manner that promotes autonomous patient motivation. Physiotherapists in the waitlist control arm (two hospitals and four primary care clinics) will not receive this training. Participants (N = 292) with chronic low back pain will complete assessments at baseline, as well as 1 week, 4 weeks, 12 weeks, and 24 weeks after their first physiotherapy appointment. Primary outcomes will include adherence to physiotherapy recommendations, as well as low back pain, function, and well-being. Participants will be blinded to treatment allocation, as they will not be told if their physiotherapist has received the communication skills training. Outcome assessors will also be blinded. \ud \ud We will use linear mixed modeling to test between arm differences both in the mean levels and the rates of change of the outcome variables. We will employ structural equation modeling to examine the process of change, including hypothesized mediation effects. \ud \ud This trial will be the first to test the effect of a self-determination theory-based communication skills training program for physiotherapists on their low back pain patients’ adherence to rehabilitation recommendations. Current Controlled Trials ISRCTN63723433\u

    Evaluation of a standard provision versus an autonomy promotive exercise referral programme: rationale and study design

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    Background The National Institute of Clinical Excellence in the UK has recommended that the effectiveness of ongoing exercise referral schemes to promote physical activity should be examined in research trials. Recent empirical evidence in health care and physical activity promotion contexts provides a foundation for testing the utility of a Self Determination Theory (SDT) -based exercise referral consultation. Methods/Design Design: An exploratory cluster randomised controlled trial comparing standard provision exercise on prescription with a Self Determination Theory-based (SDT) exercise on prescription intervention. Participants: 347 people referred to the Birmingham Exercise on Prescription scheme between November 2007 and July 2008. The 13 exercise on prescription sites in Birmingham were randomised to current practice (n=7) or to the SDT-based intervention (n=6). Outcomes measured at 3 and 6-months: Minutes of moderate or vigorous physical activity per week assessed using the 7-day Physical Activity Recall; physical health: blood pressure and weight; health status measured using the Dartmouth CO-OP charts; anxiety and depression measured by the Hospital Anxiety and Depression Scale and vitality measured by the subjective vitality score; motivation and processes of change: perceptions of autonomy support from the advisor, satisfaction of the needs for competence, autonomy, and relatedness via physical activity, and motivational regulations for exercise. Discussion This trial will determine whether an exercise referral programme based on Self Determination Theory increases physical activity and other health outcomes compared to a standard programme and will test the underlying SDT-based process model (perceived autonomy support, need satisfaction, motivation regulations, outcomes) via structural equation modelling. Trial registration The trial is registered as Current Controlled trials ISRCTN07682833

    Dental hygienists’ biopsychosocial beliefs and giving autonomy support in treatment of patients: A self-determination theory perspective

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    Objectives Self-determination theory posits that managers’ autonomy-supportive behaviour and employees’ autonomy causality orientation are motivation constructs to explain internalization of values, functioning and wellness at work. Hypothesis 1 tested whether profiles comprising perceived dental clinic managers’ autonomy-supportive, as opposed to their controlling interpersonal style, and dental hygienists’ autonomy, as opposed to their control and impersonal, causality orientations at baseline, would be positively related to dental hygienists’ biopsychosocial (BPS) beliefs and giving autonomy support in treatment of patients after 18 months. Hypothesis 2 tested whether dental hygienists’ BPS beliefs in treatment of patients will be positively associated with their autonomy-supportive behaviour given to patients after 18 months. Material and methods A prospective cohort design with 299 (Mage = 42.71; SDage = 12.62) dental hygienists completed an online survey at baseline and after 18 months. Results Latent profile and correlational analyses supported the hypotheses. Effect sizes were moderate to large. Conclusions Both perceived managerial styles and dental hygienists’ causality orientations are important for dental hygienists’ BPS beliefs and autonomy-supportive behaviours when working with dental patients.publishedVersio
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