488 research outputs found

    Combinatorial simplex algorithms can solve mean payoff games

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    A combinatorial simplex algorithm is an instance of the simplex method in which the pivoting depends on combinatorial data only. We show that any algorithm of this kind admits a tropical analogue which can be used to solve mean payoff games. Moreover, any combinatorial simplex algorithm with a strongly polynomial complexity (the existence of such an algorithm is open) would provide in this way a strongly polynomial algorithm solving mean payoff games. Mean payoff games are known to be in NP and co-NP; whether they can be solved in polynomial time is an open problem. Our algorithm relies on a tropical implementation of the simplex method over a real closed field of Hahn series. One of the key ingredients is a new scheme for symbolic perturbation which allows us to lift an arbitrary mean payoff game instance into a non-degenerate linear program over Hahn series.Comment: v1: 15 pages, 3 figures; v2: improved presentation, introduction expanded, 18 pages, 3 figure

    Identity work and the `unemployed' worker: age, disability and the lived experience of the older unemployed

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    This article seeks to explore how older individuals negotiate and manage their self-identity in relation to work while situated without paid employment. After reviewing the current positions of the older unemployed in the UK, noting the substantial overlap between age and disability, we turn our attention to conceptualizing the lived experiences of individuals through exploring `identity work' as a means of understanding a non-working work identity. Based upon focus group interviews, our empirical analysis focuses on key dimensions of participants' identity practice and how they sought to manage the following social processes: imposed identities; crafting working identities; and contesting unfavourable working identities.The conclusion contextualizes the findings against a backdrop of increasing individualistic discourses underpinning approaches to employability, closes with the policy implications arising from this study, and makes suggestions for future research agendas. </jats:p

    Evaluation of Dynamic Models of Distillation Columns with Emphasis on the Initial Response

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    The flow dynamics (tray hydraulics) are of key importance for the initial dynamic response of distillation columns. The most important parameters are the liquid holdup, the liquid hydraulic time constant and the vapor constant representing the initial effect of a change in vapor flow on liquid flow. In the paper we present methods for determining these parameters experimentally, and compare the results with estimates from available correlations such as the Francis Weir formula

    Designing theoretically-informed implementation interventions: Fine in theory, but evidence of effectiveness in practice is needed

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    The Improved Clinical Effectiveness through Behavioural Research Group (ICEBeRG) authors assert that a key weakness in implementation research is the unknown applicability of a given intervention outside its original site and problem, and suggest that use of explicit theory offers an effective solution. This assertion is problematic for three primary reasons. First, the presence of an underlying theory does not necessarily ease the task of judging the applicability of a piece of empirical evidence. Second, it is not clear how to translate theory reliably into intervention design, which undoubtedly involves the diluting effect of "common sense." Thirdly, there are many theories, formal and informal, and it is not clear why any one should be given primacy. To determine whether explicitly theory-based interventions are, on average, more effective than those based on implicit theories, pragmatic trials are needed. Until empirical evidence is available showing the superiority of theory-based interventions, the use of theory should not be used as a basis for assessing the value of implementation studies by research funders, ethics committees, editors or policy decision makers

    Disability status and multi-dimensional personal well-being among adolescents in the Southern Highlands Region of Tanzania: results of a cross-sectional study.

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    OBJECTIVE: Examine how disability status among adolescents is associated with the following domains of personal well-being: schooling, livelihoods, health, violence and psychosocial well-being. It is hypothesised that adolescents with a disability will have greater deficits in these areas of well-being compared with their healthier counterparts. DESIGN: Cross-sectional data from 2018 were obtained from the second round of an on-going study of adolescents living in poor households in two regions of the Southern Highlands of Tanzania (Iringa and Mbeya). We use the Washington Group (WG) Short Set indicators to measure disability and undertook logistic and linear multivariate regressions to understand the association between disability and the outcomes of interest. PARTICIPANTS: The sample included 2274 participants aged 15-20 years living in households participating in a government social protection programme targeted to households living in extreme poverty. RESULTS: Overall, 310 participants (14%) were classified as having disabilities. Outcomes not associated with disability status included literacy, schooling, livelihoods and self-efficacy. Adolescents with disabilities were less likely to report good or very good health (adjusted OR (aOR)=0.39, 95% CI 0.29 to 0.52) and had increased odds of reporting depressive symptoms in (aOR=1.46, 95% CI 1.11 to 1.90), emotional violence (aOR=2.18, 95% CI 1.49 to 3.20) and physical violence (aOR=1.71, 95% CI 1.13 to 2.59), compared with those without disabilities. Reports of depression were higher among men, and violence was more prevalent among women. Patterns of association were generally similar between men and women, although the association of disability with markers of well-being reached statistical significance more often among men. CONCLUSION: This study highlights areas where adolescents with disabilities are falling behind their peers in terms of personal well-being. These findings suggest that interventions may be needed to mainstream disability in programmes and policies aiming to improve well-being, mental health and violence prevention among adolescents. TRIAL REGISTRATION NUMBER: Pan African Clinical Trial Registry (PACTR201804003008116)

    Supracricoid partial laryngectomy in the management of t3 laryngeal cancer

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    Objective. To evaluate the oncologic results only in T3 glottic and supraglottic cancers regarding supracricoid partial laryngectomy (SCPL) not requiring total laryngectomy and to assess functional results by self-evaluation by the patient. Study Design. Case series with medical record review. Setting. Single tertiary care center. Subjects and Methods. Thirty-two patients with laryngeal squamous cell carcinoma, previously untreated, who underwent SCPL with cricohyoidopexy or cricohyoidoepiglottopexy were reviewed. Results. At 1, 3, and 5 years, the disease-free survival rates were 96.9%, 89.4%, and 78.2%; overall survival rates were 96.9%, 93.2%, and 87.3%; local control and locoregional control rates were 100%, 96.2%, and 96.2%; and distant metastasis-free survival rates were 100%, 100%, and 88.2%, respectively. Aspiration pneumonia was the most common complication observed. The 3 laryngeal functions (speech, swallowing, and breathing) were spared in 83.9% of patients. Conclusion. Supracricoid partial laryngectomy for selected glottic and supraglottic T3 tumors has excellent oncologic and functional results

    Genome-wide meta-analysis identifies genetic variants associated with glycemic response to sulfonylureas

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    OBJECTIVE: Sulfonylureas, the first available drugs for the management of type 2 diabetes, remain widely prescribed today. However, there exists significant variability in glycemic response to treatment. We aimed to establish heritability of sulfonylurea response and identify genetic variants and interacting treatments associated with HbA(1c) reduction. RESEARCH DESIGN AND METHODS: As an initiative of the Metformin Genetics Plus Consortium (MetGen Plus) and the DIabetes REsearCh on patient straTification (DIRECT) consortium, 5,485 White Europeans with type 2 diabetes treated with sulfonylureas were recruited from six referral centers in Europe and North America. We first estimated heritability using the generalized restricted maximum likelihood approach and then undertook genome-wide association studies of glycemic response to sulfonylureas measured as HbA(1c) reduction after 12 months of therapy followed by meta-analysis. These results were supported by acute glipizide challenge in humans who were naïve to type 2 diabetes medications, cis expression quantitative trait loci (eQTL), and functional validation in cellular models. Finally, we examined for possible drug-drug-gene interactions. RESULTS: After establishing that sulfonylurea response is heritable (mean ± SEM 37 ± 11%), we identified two independent loci near the GXYLT1 and SLCO1B1 genes associated with HbA(1c) reduction at a genome-wide scale (P < 5 × 10(−8)). The C allele at rs1234032, near GXYLT1, was associated with 0.14% (1.5 mmol/mol), P = 2.39 × 10(−8)), lower reduction in HbA(1c). Similarly, the C allele was associated with higher glucose trough levels (β = 1.61, P = 0.005) in healthy volunteers in the SUGAR-MGH given glipizide (N = 857). In 3,029 human whole blood samples, the C allele is a cis eQTL for increased expression of GXYLT1 (β = 0.21, P = 2.04 × 10(−58)). The C allele of rs10770791, in an intronic region of SLCO1B1, was associated with 0.11% (1.2 mmol/mol) greater reduction in HbA(1c) (P = 4.80 × 10(−8)). In 1,183 human liver samples, the C allele at rs10770791 is a cis eQTL for reduced SLCO1B1 expression (P = 1.61 × 10(−7)), which, together with functional studies in cells expressing SLCO1B1, supports a key role for hepatic SLCO1B1 (encoding OATP1B1) in regulation of sulfonylurea transport. Further, a significant interaction between statin use and SLCO1B1 genotype was observed (P = 0.001). In statin nonusers, C allele homozygotes at rs10770791 had a large absolute reduction in HbA(1c) (0.48 ± 0.12% [5.2 ± 1.26 mmol/mol]), equivalent to that associated with initiation of a dipeptidyl peptidase 4 inhibitor. CONCLUSIONS: We have identified clinically important genetic effects at genome-wide levels of significance, and important drug-drug-gene interactions, which include commonly prescribed statins. With increasing availability of genetic data embedded in clinical records these findings will be important in prescribing glucose-lowering drugs

    Dependence, plans to quit, quitting self-efficacy and past cessation behaviours among menthol and other flavoured cigarette users in Europe: The EUREST-PLUS ITC Europe Surveys

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    INTRODUCTION: This study characterises smoking and cessationrelated behaviours among menthol and other flavoured cigarette users in Europe prior to the implementation of the European Tobacco Products Directive (TPD) ban on the sale of flavoured cigarettes. METHODS: An analysis of cross-sectional data from the 2016 EUREST-PLUS ITC Europe Surveys was conducted among a sample of 10760 adult smokers from eight European Union Member States. Respondents were classified as menthol, other flavoured, unflavoured, or no usual flavour cigarette users and compared on smoking and cessation behaviours and characteristics. Data were analysed in SPSS Complex Samples Package using bivariate and multivariate regression analyses adjusted for sociodemographic characteristics, dependence, and country. RESULTS: In bivariate analyses, cigarette flavour was significantly associated with all outcomes (p<0.001). After adjusting for sociodemographic characteristics, these associations attenuated but remained significant and in the same direction for dependence, self-efficacy, plans to quit, past quit attempts, and ever e-cigarette use. In fully adjusted models, compared to smokers of non-flavoured cigarettes, menthol smokers were less likely to smoke daily (AOR=0.47, 95% CI: 0.32–0.71), smoke within 30 min of waking (0.52,0.43–0.64), consider themselves addicted (0.74,0.59–0.94), and more likely to have ever used e-cigarettes (1.26,1.00–1.57); other flavoured cigarette smokers were less likely to smoke daily (0.33,0.15–0.77), and have higher self-efficacy (1.82,1.20–2.77); no usual flavour smokers were less likely to smoke daily (0.34,0.22–0.51), smoke within 30 min of waking (0.66,0.55–0.80), consider themselves addicted (0.65,0.52–0.78), have ever made a quit attempt (0.69,0.58– 0.84), have ever used e-cigarettes (0.66,0.54–0.82), and had higher self-efficacy (1.46,1.19–1.80). CONCLUSIONS: Smokers of different cigarette flavours in Europe differ on smoking and cessation characteristics. The lower dependence of menthol cigarette smokers could lead to greater success rates if quit attempts are made, however cross-country differences in smoking behaviours and quitting intentions could lead to the TPD ban on cigarette flavours having differential impact if not accompanied by additional measures, such as smoking cessation support
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