525 research outputs found

    Sublinear-Time Language Recognition and Decision by One-Dimensional Cellular Automata

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    After an apparent hiatus of roughly 30 years, we revisit a seemingly neglected subject in the theory of (one-dimensional) cellular automata: sublinear-time computation. The model considered is that of ACAs, which are language acceptors whose acceptance condition depends on the states of all cells in the automaton. We prove a time hierarchy theorem for sublinear-time ACA classes, analyze their intersection with the regular languages, and, finally, establish strict inclusions in the parallel computation classes SC\mathsf{SC} and (uniform) AC\mathsf{AC}. As an addendum, we introduce and investigate the concept of a decider ACA (DACA) as a candidate for a decider counterpart to (acceptor) ACAs. We show the class of languages decidable in constant time by DACAs equals the locally testable languages, and we also determine Ω(n)\Omega(\sqrt{n}) as the (tight) time complexity threshold for DACAs up to which no advantage compared to constant time is possible.Comment: 16 pages, 2 figures, to appear at DLT 202

    Self Management Activation Randomised Trial for Prostatitis (SMART-P): study protocol for a randomised controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Chronic prostatitis otherwise known as chronic pelvic pain syndrome is a common urological diagnosis that causes many men significant morbidity and has a detrimental effect on their quality of life. Standard treatment with antibiotics and simple analgesia are often ineffective and many patients are managed by the chronic pain services.</p> <p>Cognitive behavioural therapy has been shown to be helpful in the management of many chronic diseases and has recently been proposed as an effective treatment for chronic prostatitis. Furthermore, a self management programme administered to groups of men with lower urinary tract symptoms has been shown to be more effective than standard treatments including surgery.</p> <p>Therefore, we have developed a cognitive behavioural therapy programme specifically for men with chronic prostatitis. This novel treatment approach will be compared to conventional therapy in the pain clinic such as atypical analgesia and local anaesthetic injections in the context of a randomised controlled trial.</p> <p>Methods/Design</p> <p>Men will be recruited from general urology outpatient clinics following the exclusion of other diagnoses that could be responsible for their symptoms. Men will be randomised to attend either a self management healthcare and education programme or to pain clinic referral alone. The self management programme will be administered by a clinical psychologist to small groups of men over six consecutive weekly sessions each lasting two hours. Patients will be taught techniques of problem-solving and goal-setting and will learn coping mechanisms and how to modify catastrophic cognition.</p> <p>The primary outcome will be change from baseline in the National Institute of Health Chronic Prostatitis Symptom Index, a validated instrument for the assessment of men with chronic prostatitis. Secondary outcomes include generic quality of life scores and analgesic and drug usage. Outcomes will be assessed at 2, 6 and 12 months.</p> <p>Discussion</p> <p>If this group administered self management programme is shown to be effective in the treatment of men with chronic prostatitis it may become the new standard of care for these patients. Furthermore, it may be adapted for use in women with interstitial cystitis, a condition which is analogous to chronic prostatitis in men.</p> <p>Trial Registration</p> <p>Current Controlled Trials <a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=ISRCTN21012555">ISRCTN21012555</a></p

    Computer aided synthesis: a game theoretic approach

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    In this invited contribution, we propose a comprehensive introduction to game theory applied in computer aided synthesis. In this context, we give some classical results on two-player zero-sum games and then on multi-player non zero-sum games. The simple case of one-player games is strongly related to automata theory on infinite words. All along the article, we focus on general approaches to solve the studied problems, and we provide several illustrative examples as well as intuitions on the proofs.Comment: Invitation contribution for conference "Developments in Language Theory" (DLT 2017

    Association between fast food purchasing and the local food environment

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    Objective: In this study, an instrument was created to measure the healthy and unhealthy characteristics of food environments and investigate associations between the whole of the food environment and fast food consumption.Design and subjects: In consultation with other academic researchers in this field, food stores were categorised to either healthy or unhealthy and weighted (between +10 and &minus;10) by their likely contribution to healthy/unhealthy eating practices. A healthy and unhealthy food environment score (FES) was created using these weightings. Using a cross-sectional study design, multilevel multinomial regression was used to estimate the effects of the whole food environment on the fast food purchasing habits of 2547 individuals.Results: Respondents in areas with the highest tertile of the healthy FES had a lower likelihood of purchasing fast food both infrequently and frequently compared with respondents who never purchased, however only infrequent purchasing remained significant when simultaneously modelled with the unhealthy FES (odds ratio (OR) 0.52; 95% confidence interval (CI) 0.32&ndash;0.83). Although a lower likelihood of frequent fast food purchasing was also associated with living in the highest tertile of the unhealthy FES, no association remained once the healthy FES was included in the models. In our binary models, respondents living in areas with a higher unhealthy FES than healthy FES were more likely to purchase fast food infrequently (OR 1.35; 95% CI 1.00&ndash;1.82) however no association was found for frequent purchasing.Conclusion: Our study provides some evidence to suggest that healthier food environments may discourage fast food purchasing.<br /

    High Diet Quality Is Associated with a Lower Risk of Cardiovascular Disease and All-Cause Mortality in Older Men

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    Although diet quality is implicated in cardiovascular disease (CVD) risk, few studies have investigated the relation between diet quality and the risks of CVD and mortality in older adults. This study examined the prospective associations between dietary scores and risk of CVD and all-cause mortality in older British men. A total of 3328 men (aged 60–79 y) from the British Regional Heart Study, free from CVD at baseline, were followed up for 11.3 y for CVD and mortality. Baseline food-frequency questionnaire data were used to generate 2 dietary scores: the Healthy Diet Indicator (HDI), based on WHO dietary guidelines, and the Elderly Dietary Index (EDI), based on a Mediterranean-style dietary intake, with higher scores indicating greater compliance with dietary recommendations. Cox proportional hazards regression analyses assessed associations between quartiles of HDI and EDI and risk of all-cause mortality, CVD mortality, CVD events, and coronary heart disease (CHD) events. During follow-up, 933 deaths, 327 CVD deaths, 582 CVD events, and 307 CHD events occurred. Men in the highest compared with the lowest EDI quartile had significantly lower risks of all-cause mortality (HR:0.75; 95% CI: 0.60, 0.94; P-trend = 0.03), CVD mortality (HR: 0.63; 95% CI: 0.42, 0.94; P-trend = 0.03), and CHD events(HR: 0.66; 95% CI: 0.45,0.97; P-trend = 0.05) but not CVD events (HR: 0.79; 95% CI: 0.60, 1.05;P-trend = 0.16) after adjustment for sociodemographic, behavioral, and cardiovascular risk factors. The HDI was not significantly associated with any of the outcomes. The EDI appears to be more useful than the HDI for assessing diet quality in relation to CVD and morality risk in older men. Encouraging older adults to adhere to the guidelines inherent in the EDI criteria may have public health benefit

    Functional identity versus species richness: herbivory resistance in plant communities

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    The resistance of a plant community against herbivore attack may depend on plant species richness, with monocultures often much more severely affected than mixtures of plant species. Here, we used a plant–herbivore system to study the effects of selective herbivory on consumption resistance and recovery after herbivory in 81 experimental grassland plots. Communities were established from seed in 2002 and contained 1, 2, 4, 8, 16 or 60 plant species of 1, 2, 3 or 4 functional groups. In 2004, pairs of enclosure cages (1 m tall, 0.5 m diameter) were set up on all 81 plots. One randomly selected cage of each pair was stocked with 10 male and 10 female nymphs of the meadow grasshopper, Chorthippus parallelus. The grasshoppers fed for 2 months, and the vegetation was monitored over 1 year. Consumption resistance and recovery of vegetation were calculated as proportional changes in vegetation biomass. Overall, grasshopper herbivory averaged 6.8%. Herbivory resistance and recovery were influenced by plant functional group identity, but independent of plant species richness and number of functional groups. However, herbivory induced shifts in vegetation composition that depended on plant species richness. Grasshopper herbivory led to increases in herb cover at the expense of grasses. Herb cover increased more strongly in species-rich mixtures. We conclude that selective herbivory changes the functional composition of plant communities and that compositional changes due to selective herbivory depend on plant species richness

    np elastic spin-transfer measurements at 485 and 635 MeV

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    Journals published by the American Physical Society can be found at http://publish.aps.org/We have measured the spin-transfer parameters K(LL), K(SL), K(LS) and K(SS) at 635 MeV from 50-degrees to 178-degrees c.m. and at 485 MeV from 74-degrees to 176-degrees c.m. These new data have a significant impact on the phase-shift analyses. There are now sufficient data near these energies to overdetermine the elastic nucleon-nucleon amplitudes

    np elastic spin transfer measurements at 788 MeV

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    Journals published by the American Physical Society can be found at http://publish.aps.org/We have measured the spin-transfer parameters K(LL), K(SL), K(LS), and K(SS) at 788 MeV from 47-degrees to 177-degrees c.m., and also uncovered a 10-16 % normalization discrepancy which affects all previous np elastic spin data from LAMPF. Results disagree significantly from previous phase-shift predictions. With the inclusion of these new data the NN phase shifts and amplitudes (isospin 0 and 1) become well determined for the first time near 800 MeV
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