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Nonsignificant Results (nonsignificant + result)
Selected AbstractsTechnological novelty and open-endedness: Two characteristics of interactive exhibits that contribute to the holding of visitor attention in a science museumJOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 2 2003Cody Sandifer This study was undertaken to isolate characteristics of interactive exhibits that are particularly effective in attracting and holding the attention of visitors in a science museum. Forty-seven visitors were tracked through two adjacent exhibitions, comprising a total of 61 interactive exhibits. Four exhibit characteristics were identified and examined: technological novelty, user-centeredness, sensory stimulation, and open-endedness. Regression analyses show that two of these characteristics, technological novelty and open-endedness, help to account for the variance in average visitor holding time; these characteristics have positive correlations with the amount of time spent by visitors at exhibits. Nonsignificant results are explained in terms of mitigating environmental and exhibit-related factors. In addition, topics for future study are suggested. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 40: 121,137, 2003 [source] POWER AND POTENTIAL BIAS IN FIELD STUDIES OF NATURAL SELECTIONEVOLUTION, Issue 3 2004Erika I. Hersch Abstract The advent of multiple regression analyses of natural selection has facilitated estimates of both the direct and indirect effects of selection on many traits in numerous organisms. However, low power in selection studies has possibly led to a bias in our assessment of the levels of selection shaping natural populations. Using calculations and simulations based on the statistical properties of selection coefficients, we find that power to detect total selection (the selection differential) depends on sample size and the strength of selection relative to the opportunity of selection. The power of detecting direct selection (selection gradients) is more complicated and depends on the relationship between the correlation of each trait and fitness and the pattern of correlation among traits. In a review of 298 previously published selection differentials, we find that most studies have had insufficient power to detect reported levels of selection acting on traits and that, in general, the power of detecting weak levels of selection is low given current study designs. We also find that potential publication bias could explain the trend that reported levels of direct selection tend to decrease as study sizes increase, suggesting that current views of the strength of selection may be inaccurate and biased upward. We suggest that studies should be designed so that selection is analyzed on at least several hundred individuals, the total opportunity of selection be considered along with the pattern of selection on individual traits, and nonsignificant results be actively reported combined with an estimate of power. [source] Effectiveness of a School-Based Intervention at Changing Preadolescents' Tobacco Use and AttitudesJOURNAL OF SCHOOL HEALTH, Issue 6 2002Esther M. VanDyke MD ABSTRACT: This study evaluated the effectiveness of a tobacco intervention on preadolescents' tobacco use and attitudes. A tobacco assessment questionnaire was distributed to seventh-grade students in May 1997 (N = 229) and 1999 (N = 230). During the 1998,1999 academic year, sixth-grade students at the intervention school received a tobacco intervention. Though not statistically significant the number of smokers at the intervention school decreased from 43.2% to 31.1% after the intervention (p = .09). These students predicted less smoking in five years (29.6% to 19.8%, p = .078) and 20 years (28.4% to 13.2%, p = .004). Because of the difficulty in reducing smoking rates at the population level, the nonsignificant results can be viewed as a success rather than a setback. When faced with increasing use trends, an intervention can at least hope to achieve a decrease or slow the rate of growth, and the program succeeded in that respect. School-based interventions can effectively influence preadolescent' attitudes concerning tobacco use. Future programs should begin earlier and be reinforced yearly. [source] Markers of physiological stress in juvenile bonobos (Pan paniscus): Are enamel hypoplasia, skeletal development and tooth size interrelated?AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2009John R. Lukacs Abstract A reduction in enamel thickness due to disrupted amelogenesis is referred to as enamel hypoplasia (EH). Linear EH in permanent teeth is a widely accepted marker of systemic physiological stress. An enigmatic, nonlinear form of EH commonly manifest in great ape and human deciduous canines (dc) is known as localized hypoplasia of primary canines (LHPC). The etiology of LHPC and what it signifies,localized traumatic or systemic physiological stress,remains unclear. This report presents frequency data on LHPC, hypostotic cranial traits, and tooth size in a sample of juvenile bonobos, then tests hypotheses of intertrait association that improve knowledge of the etiology and meaning of LHPC. The fenestration hypothesis is tested using hypostotic cranial traits as a proxy for membrane bone ossification, and the relationship between tooth size, LHPC, and hypostosis is investigated. Macroscopic observations of EH, hypostotic traits, and measurements of buccolingual tooth size were conducted according to established standards. LHPC was found in 51.2% of bonobos (n = 86) and in 26% of dc teeth (n = 269). Hypostotic traits were observed in 55.2% of bonobos (n = 96). A test of the association between LHPC and hypostosis yielded nonsignificant results (,2 = 2.935; P = 0.0867). Primary canines were larger in specimens with LHPC than in unaffected specimens (paired samples t test; udc, P = 0.011; ldc, P = 0.018), a result consistent with the fenestration hypothesis of LHPC pathogenesis. Hypostosis was not associated with differences in tooth size (P > 0.05). LHPC may be an indirect indicator of physiological stress, resulting from large, buccally displaced primary canines. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] Aerodigestive Tract Invasion by Well-Differentiated Thyroid Carcinoma: Diagnosis, Management, Prognosis, and BiologyTHE LARYNGOSCOPE, Issue 1 2006Judith Czaja McCaffrey MD Objectives/Hypothesis: 1) To describe the clinical entity invasive well-differentiated thyroid carcinoma (IWDTC), 2) to determine prognostic factors for survival in patients with IWDTC, 3) to describe and compare types of surgical resection to determine treatment efficacy, 4) to offer a staging system and surgical algorithm for management of patients with IWDTC, 5) to examine alterations in expression of E-cadherin and ,-catenin adhesion molecules in three groups of thyroid tissue and propose a cellular mechanism for invasion of the aerodigestive tract. Study Design: Basic science: quantification of expression of E-cadherin and ,-catenin in three groups of thyroid tissue. Clinical: retrospective review of patients with IWDTC surgically treated and followed over a 45-year time period. Methods: Basic science: immunohistochemical staining was used with antibodies against E-cadherin and ,-catenin in three groups of tissue: group 1, normal control thyroid tissue (n = 10); group 2, conventional papillary thyroid carcinoma (n = 20); group 3, IWDTC (n = 12). Intensity scores were given on the basis of protocol. One-way analysis of variance (ANOVA) was used to evaluate differences between groups. Post hoc ANOVA testing was completed. P < .05 was significant. Clinical: patients were divided into three surgical groups within the laryngotracheal subset: group 1, complete resection of gross disease (n = 34); group 2, shave excision (n = 75); group 3, incomplete excision (n = 15). Cox regression analysis was used to determine significance of prognostic factors. Kaplan-Meier plots were used to evaluate survival. P < .05 was significant. Results: Basic science: a significant difference between the three thyroid tissue groups for E-cadherin expression was demonstrated on one-way ANOVA testing. When controls were compared with either experimental group in post hoc ANOVA testing, differences between all groups were demonstrated (P < .001). For ,-catenin, the intensities of the three groups were not different by one-way ANOVA testing. Similar nonsignificant results were found on post hoc ANOVA testing. Clinical: there was a statistically significant difference in survival for patients with and without involvement of any portion of the endolarynx or trachea (P < .01). There was a significant difference among all three surgical groups when compared (P < .001). When complete and shave groups were compared with gross residual group there was a significant decrease in survival in incomplete resection group (P < .01). Cox regression analysis demonstrated invasion of larynx and trachea were significant prognostic factors for poor outcome. The type of initial resection was significant on multivariate analysis. Removal of all gross disease is a major factor for survival. Conclusions: Basic science: there is a decrease in membrane expression of E-cadherin in IWDTC, and loss of this tumor suppressor adhesion molecule may contribute to the invasive nature of well-differentiated thyroid carcinomas. Clinical: laryngotracheal invasion is a significant independent prognostic factor for survival. Patients undergoing shave excision had similar survival when compared with those undergoing radical tumor resection if gross tumor did not remain. Gross intraluminal tumor should be resected completely. Shave excision is adequate for minimal invasion not involving the intraluminal surfaces of the aerodigestive tract. [source] | |||||||||||||