1,318 research outputs found

    The Connectivity of Boolean Satisfiability: Computational and Structural Dichotomies

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    Boolean satisfiability problems are an important benchmark for questions about complexity, algorithms, heuristics and threshold phenomena. Recent work on heuristics, and the satisfiability threshold has centered around the structure and connectivity of the solution space. Motivated by this work, we study structural and connectivity-related properties of the space of solutions of Boolean satisfiability problems and establish various dichotomies in Schaefer's framework. On the structural side, we obtain dichotomies for the kinds of subgraphs of the hypercube that can be induced by the solutions of Boolean formulas, as well as for the diameter of the connected components of the solution space. On the computational side, we establish dichotomy theorems for the complexity of the connectivity and st-connectivity questions for the graph of solutions of Boolean formulas. Our results assert that the intractable side of the computational dichotomies is PSPACE-complete, while the tractable side - which includes but is not limited to all problems with polynomial time algorithms for satisfiability - is in P for the st-connectivity question, and in coNP for the connectivity question. The diameter of components can be exponential for the PSPACE-complete cases, whereas in all other cases it is linear; thus, small diameter and tractability of the connectivity problems are remarkably aligned. The crux of our results is an expressibility theorem showing that in the tractable cases, the subgraphs induced by the solution space possess certain good structural properties, whereas in the intractable cases, the subgraphs can be arbitrary

    Identification of peptides in traditional and probiotic sheep milk yoghurt with angiotensin I-converting enzyme (ACE)-inhibitory activity

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    Two sets of traditional Greek sheep milk yoghurt were produced: the first one (YC) using normal yoghurt culture (Lactobacillus delbrueckii subsp. bulgaricus !10.13 and Streptococcus thermophilus !10.7) and the second (PR) with the same normal culture mixed with Lactobacillus paracasei subsp. paracasei DC412. YC and PR had similar physicochemical properties and proteolysis patterns throughout storage. Both products showed similar peptide profiles by RP-HPLC but quantitative differences were observed in respect to storage time. Single-strain cultures of the microorganisms used showed similar peptide profiles for both lactobacilli, yet L. delbrueckii subsp. bulgaricus was the most proteolytic of all three microorganisms. The peptide content and the ACE-inhibitory activity of the water-soluble extracts of yoghurts, YC and PR, increased throughout storage. Major peptides were identified from yoghurt PR and from the separate cultures of L. delbrueckii subsp. bulgaricus and L. paracasei subsp. paracasei. Most of these peptides were derived from b-casein. A peptide, b-CN f114-121, with well-established ACE-inhibitory and opiate-like activity was identified in yoghurt PR. Further identified peptides were regarded as potential ACE-inhibitors according to their sequence

    Excessive weight gain after remission of depression in a schizophrenic patient treated with risperidone: case report

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    BACKGROUND: The use of atypical antipsychotics in schizophrenic patients has been associated with a risk of weight gain. Similarly, recovery from depression is often followed by improved appetite, greater food intake and potential increase in weight. CASE PRESENTATION: A Caucasian 33-year-old schizophrenic female patient was being treated with 6 mg/day of risperidone and 15 mg/day of clorazepate. She developed depressive symptomatology and 40 mg/day of fluoxetine was gradually added to her treatment regimen for about 9 months. After the remission of depression, and the discontinuation of fluoxetine, she experienced an increase in appetite and subsequently excessive weight gain of 52 kg. Re-administration of fluoxetine did not reverse the situation. The patient developed diabetes mellitus, which was successfully controlled with metformin 1700 mg/day. The addition at first of orlistat 360 mg/day and later of topiramate 200 mg/day has helped her to lose a significant part of the weight gained (30 kg). CONCLUSION: The case suggests a probable association between the remission of depressive symptomatology and weight gain in a schizophrenic patient

    The Complexity of Computing a Nash Equilibrium

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    The Adoption of Mediterranean Diet Attenuates the Development of Acute Coronary Syndromes in People with the Metabolic Syndrome

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    OBJECTIVES: In this work we investigated the effect of the consumption of the Mediterranean diet on coronary risk, in subjects with the metabolic syndrome. METHODS: During 2000–2002, we randomly selected, from all Greek regions, 848 hospitalised patients (695 males, 58 ± 10 & 153 females, 65 ± 9 years old) with a first event of acute coronary syndrome and 1078 frequency matched, by sex, age, region controls, without any suspicious for cardiovascular disease. Nutritional habits were evaluated through a validated questionnaire, while the metabolic syndrome was defined according to the NCEP ATP III criteria. Mediterranean diet was defined according to the guidelines of the Division of Nutrition/Epidemiology, of Athens Medical School. RESULTS: Of the 1926 participants, 307 (36.2%) of the patients and 198 (18.4%) of the controls (P < 0.001) met the ATP III criteria. This was related with 2fold adjusted coronary risk (odds ratio = 2.35, 95% 1.87 – 2.84) in subjects with the metabolic syndrome as compared with the rest of them. No differences were observed concerning the prevalence of the metabolic syndrome and sex of subjects, after adjustment for group of study (P > 0.1). Eighty (26%) of the patients and 70 (35%) of the controls (P < 0.01) with the metabolic syndrome were "closer" to the Mediterranean diet. Multivariate analysis revealed that the adoption of this diet is associated with a 35% (odds ratio = 0.65, 95% 0.44 – 0.95) reduction of the coronary risk in subjects with the metabolic syndrome, after adjusting for age, sex, educational and financial level and the conventional cardiovascular risk factors. CONCLUSION: Consequently, the adoption of Mediterranean diet seems to attenuate the coronary risk in subjects with the metabolic syndrome

    Passion in the Workplace: Empirical Insights from Team Sport Organisations

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    Although sport management scholars have focused on a fairly wide number of psychologically-related constructs in the workplace, passion has not been part of this research agenda. The present study is the first attempt to fill this gap by exploring employees’ passion in the workplace setting of sport organisations. It does so by applying for the first time the dualistic model of passion developed by Vallerand et al. (2003), which measures two distinct types of passion: harmonious and obsessive. Online survey data were gathered from administrative employees in the United Kingdom’s football industry, responsible for either business-related functions or the clubs’ social agenda (N=236) in order to measure the passion experienced by individuals guided by different institutional logics. The particular instrument has two components: harmonious and obsessive passion towards the job. Besides the passion scales, the survey contained measures related to demographic variables (e.g., age, gender and education), to employment position in the organisation and to previous job experience. Data were statistically analysed in Confirmatory Factor Analysis (CFA) and analysis of variance, using SPSS and Amos 18.0. To determine the effect of contextual variables on the passion for the job, t-test and ANOVA were also used. Both groups of employees are passionate about their job. They remain harmoniously passionate throughout their career and show low level of obsessive passion. The type of work activities influences both levels of harmonious and obsessive passion experienced by personnel within sport organisations with employees responsible for the social agenda being slightly more harmoniously and obsessively passionate compared to those responsible for the business agenda. Vallerand et al.’s (2003) dualistic model of passion has been adapted to measure passion at workplace within sport organisations. The particular working environment that forms these organisations attracts and/or facilitates employees to experience a positive work–life balance

    Four cycles of paclitaxel and carboplatin as adjuvant treatment in early-stage ovarian cancer: a six-year experience of the Hellenic Cooperative Oncology Group

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    BACKGROUND: Surgery can cure a significant percentage of ovarian carcinoma confined to the pelvis. Nevertheless, there is still a 10–50% recurrence rate. We administered paclitaxel/carboplatin as adjuvant treatment in early-stage ovarian carcinoma. METHODS: Patients with stages Ia or Ib, Grade 2 or 3 and Ic to IIb (any grade) were included. Patients were treated with 4 cycles of Paclitaxel 175 mg/m(2 )and Carboplatin [area under the curve (AUC) 6 (Calvert Formula)] every 3 weeks. RESULTS: Sixty-nine patients with no residual disease following cytoreductive surgery and minimal or modified surgical staging were included in this analysis. Grade 3 or 4 neutropenia occured in 29.9% of patients, while neutropenic fever was reported in 4.5%. Neurotoxicity (all Grade 1 or 2) was reported in 50% of cases. Median follow-up was 62 months. 5-year overall survival (OS) and relapse-free survival (RFS) were: 87% (95% confidence intervals [CI]: 78–96) and 79% (95% CI: 69–89), respectively. Significantly fewer patients with stages Ic-IIb and tumor grade 2 or 3 achieved a 5-year RFS than patients with only one of these two factors (73% vs 92%, p = 0.03). CONCLUSION: Paclitaxel/Carboplatin chemotherapy is a safe and effective adjuvant treatment in early-stage ovarian carcinoma. Patients with stages Ic-IIb and tumor grade 2 or 3 may benefit from more extensive treatment
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