On a clique covering problem of orlin

AbstractLet T2n be the complement of a perfect matching in the complete graph on 2n vertices, and cc(T2n) be the minimum number of complete subgraphs necessary to cover all the edges of T2n Orlin posed the problem of determining the asymptotic behaviour of cc(T2n). We show that cc(T2n)=min{k:n⩽(k−1⌈k2⌉)} for all n>1, (which implies that limn→∞cc(T 2n)/log2n=1). This is done by applying a Sperner-type theorem on set families due to Bollobás and Schönheim

Residential proximity to major roadways and prevalent hypertension among postmenopausal women: results from the Women's Health Initiative San Diego Cohort.

BackgroundLiving near major roadways has been linked with increased risk of cardiovascular events and worse prognosis. Residential proximity to major roadways may also be associated with increased risk of hypertension, but few studies have evaluated this hypothesis.Methods and resultsWe examined the cross-sectional association between residential proximity to major roadways and prevalent hypertension among 5401 postmenopausal women enrolled into the San Diego cohort of the Women's Health Initiative. We used modified Poisson regression with robust error variance to estimate the association between prevalence of hypertension and residential distance to nearest major roadway, adjusting for participant demographics, medical history, indicators of individual and neighborhood socioeconomic status, and for local supermarket/grocery and fast food/convenience store density. The adjusted prevalence ratios for hypertension were 1.22 (95% CI: 1.07, 1.39), 1.13 (1.00, 1.27), and 1.05 (0.99, 1.12) for women living ≤100, >100 to 200, and >200 to 1000 versus >1000 m from a major roadway (P for trend=0.006). In a model treating the natural log of distance to major roadway as a continuous variable, a shift in distance from 1000 to 100 m from a major roadway was associated with a 9% (3%, 16%) higher prevalence of hypertension.ConclusionsIn this cohort of postmenopausal women, residential proximity to major roadways was positively associated with the prevalence of hypertension. If causal, these results suggest that living close to major roadways may be an important novel risk factor for hypertension

Fetal programming and gestational diabetes mellitus

Gestational diabetes mellitus is defined by new-onset glucose intolerance during pregnancy. About 2–5% of all pregnant women develop gestational diabetes during their pregnancies and the prevalence has increased considerably during the last decade. This metabolic condition is manifested when pancreatic β-cells lose their ability to compensate for increased insulin resistance during pregnancy, however, the pathogenesis of the disease remains largely unknown. Gestational diabetes is strongly associated with adverse pregnancy outcome as well as with long-term adverse effects on the offspring which likely occurs due to epigenetic modifications of the fetal genome. In the current review we address gestational diabetes and the short and long term complications for both mothers and offspring focusing on the importance of fetal programming in conferring risk of developing diseases in adulthood

Texas Beef Industry Database (BEEFSYS)

Last updated: 6/12/200

Compliance with behavioral guidelines for diet, physical activity and sedentary behaviors is related to insulin resistance among overweight and obese youth

Abstract Background Overweight and obesity are established risk factors for insulin resistance in youth. A number of behavioral recommendations have been publicized with the goal of improving glycemic control. However, there is limited information about whether meeting these behavioral recommendations actually reduces insulin resistance. Findings 92 youths 11 - 16 years with BMI ≥ 85% underwent oral glucose tolerance testing. HOMA-IR and AUCInsulin/AUCGlucose were calculated as measures of insulin resistance. Dietary and physical activity (PA) measures were performed. Assessments included whether or not participants met recommended levels of diet, PA and sedentary behaviors. 62% youths met criteria for insulin resistance. 82% (75/92) met at least one behavioral recommendation. Participants who met ≥ 1 dietary, sedentary, or PA recommendations had significantly reduced insulin resistance as compared with youth who did not. This relationship remained significant in multivariate modeling of insulin resistance adjusting for age, sex, and BMI. Conclusions Even relatively minor behavior change may reduce insulin resistance in youth at risk for diabetes. Our findings support the relevance of current behavioral interventions for glycemic control. Trials Registration Clinical Trials #NCT00412165

Reliability and validity of brief psychosocial measures related to dietary behaviors

<p>Abstract</p> <p>Background</p> <p>Measures of psychosocial constructs are required to assess dietary interventions. This study evaluated brief psychosocial scales related to 4 dietary behaviors (consumption of fat, fiber/whole grains, fruits, and vegetables).</p> <p>Methods</p> <p>Two studies were conducted. Study 1 assessed two-week reliability of the psychosocial measures with a sample of 49 college students. Study 2 assessed convergent and discriminant validity of the psychosocial measures with dietary nutrient estimates from a Food Frequency Questionnaire on 441 men and 401 women enrolled in an Internet-based weight loss intervention study.</p> <p>Results</p> <p>Study 1 test-retest reliability ICCs were strong and ranged from .63 to .79. In study 2, dietary fat cons, fiber/whole grain cons and self-efficacy, fruit and vegetable cons and self-efficacy, and healthy eating social support, environmental factors, enjoyment, and change strategies demonstrated adequate correlations with the corresponding dietary nutrient estimates.</p> <p>Conclusions</p> <p>Brief psychosocial measures related to dietary behaviors demonstrated adequate reliability and in most cases validity. The strongest and most consistent scales related to dietary behaviors were healthy eating change strategies and enjoyment. Consistent convergent validity was also found for the cons of change scales. These measures can be used in intervention studies to evaluate psychosocial mediators of dietary change in overweight and obese individuals.</p

The Construct and Predictive Validity of Instruments Measuring the Psychosocial Correlates of Television Viewing

Background: Many studies have examined the consequences of prolonged television viewing, but few studies have examined the psychological states that contribute to this behavior. In this study, we evaluated the construct and predictive validity of psychosocial correlates of television viewing in a population of African American (AA) breast cancer survivors (BCS). Methods: AA BCS (N = 342, Mean age = 54 years) completed measures of decisional balance, self-efficacy, family support, and time spent watching television online. Exploratory structural equation modeling (ESEM) was used to examine the construct and predictive validity as well as the differential item functioning of the instruments among population subgroups. Results: The construct validity of the measures was supported among subgroups. The scales were measuring the construct similarly among the education and body size groups, but not among age groups. Subsequent analysis indicated that pros (β = -0.19, P \u3c 0.05), cons (β = 0.18, P \u3c 0.05), and self-efficacy (β = -0.16, P \u3c 0.05) were significantly associated with time spent watching television. Conclusions: Minor modifications may be needed to support the validity and reliability of the decisional balance and self-efficacy subscales among older survivors. More studies are needed to modify these measures to establish sufficient levels of construct and predictive validity in this population

Using Pectoral Fin Rays as a Non-lethal Aging Structure for Smallmouth Bass: Precision with Otolith Age Estimates and the Importance of Reader Experience

We evaluated the potential utility of pectoral fin rays as non-lethal aging structures for smallmouth bass (Micropterus dolomieu). We compared age estimates among three reading pairs and against sectioned sagittal otolith age estimates for precision. Reading pair bias was not detected, although the highest rates of age estimate agreement occurred between reading pairs with high and moderate aging experience. Precision of otolith and fin ray age estimates were equivalent based on between-structure comparisons of average percent error and coefficient of variation. However, fin rays underestimated fish age compared to otoliths for older fish, especially when aged by less-experienced readers. Pectoral fin rays may provide a non-lethal alternative to otoliths for aging smallmouth bass, particularly for younger fish (≤age 4) or when experienced readers conduct aging. Additional evaluations of fin rays as smallmouth bass aging structures are needed, including validation using known-age fish and documentation of consistent annulus formation throughout a fish’s life

Brief scales to assess physical activity and sedentary equipment in the home

<p>Abstract</p> <p>Background</p> <p>Sedentary behaviors such as TV viewing are associated with childhood obesity, while physical activity promotes healthy weight. The role of the home environment in shaping these behaviors among youth is poorly understood. The study purpose was to examine the reliability of brief parental proxy-report and adolescent self-report measures of electronic equipment and physical activity equipment in the home and to assess the construct validity of these scales by examining their relationship to physical activity, sedentary behavior, and weight status of children and adolescents.</p> <p>Methods</p> <p>Participants were adolescents (n = 189; mean age = 14.6), parents of adolescents (n = 171; mean age = 45.0), and parents of younger children (n = 116; parents mean age = 39.6; children's mean age = 8.3) who completed two surveys approximately one month apart. Measures included a 21-item electronic equipment scale (to assess sedentary behavior facilitators in the home, in the child or adolescent's bedroom, and portable electronics) and a 14-item home physical activity equipment scale. Home environment factors were examined as correlates of children's and adolescents' physical activity, sedentary behavior, and weight status after adjusting for child age, sex, race/ethnicity, household income, and number of children in the home.</p> <p>Results</p> <p>Most scales had acceptable test-retest reliability (intraclass correlations were .54 - .92). Parent and adolescent reports were correlated. Electronic equipment in adolescents' bedrooms was positively related to sedentary behavior. Activity equipment in the home was inversely associated with television time in adolescents and children, and positively correlated with adolescents' physical activity. Children's BMI z-score was positively associated with having a television in their bedroom.</p> <p>Conclusions</p> <p>The measures of home electronic equipment and activity equipment were similarly reliable when reported by parents and by adolescents. Home environment attributes were related to multiple obesity-related behaviors and to child weight status, supporting the construct validity of these scales.</p