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Main Effects (main + effects)
Kinds of Main Effects Selected AbstractsPsychosocial outcomes in children two years after epilepsy surgery: Has anything changed?EPILEPSIA, Issue 4 2008Irene M. Elliott Summary Purpose: We prospectively explored psychosocial outcomes in children (7,18 years) 2 years after epilepsy surgery. This study built on our previous one that examined these children 1 year after surgery. Methods: Twenty children were studied using the Child Behavior Checklist (CBCL; a parent report instrument of potential behavioral and social problems) preoperatively, 1 year and 2 years after surgery. A comparison group of 12 children with medically refractory seizures was examined at comparable times. We conducted mixed factorial ANOVAs to determine group, time, and interaction effects, and regression analyses to assess factors driving significant (p , 0.05) interactions. We also investigated the proportion of children scoring in the abnormal range over time. Results: Significant main effects of time were observed on total behavior, externalizing, aggression, and delinquent behavior scales, with both groups reporting improvement. Main effects of group were observed for withdrawn and total competence scales, with the surgical group demonstrating favorable scores. Significant group × time interactions were observed on the social and social problems subscales. On both subscales, the surgical group demonstrated improvement over time, whereas the nonsurgical group experienced decline. Fifty percent of the surgical group remained seizure-free. Seizure status and number of antiepileptic medications predicted changes in social scores. We did not observe a significant regression model for the social problems subscale. Discussion: These findings suggest that change in social function may take time to develop after surgery. Prospective studies designed for longer periods are required to determine if improvements in other psychosocial domains are seen over time. [source] The Perceptions of Infant Distress Signals Varying in Pitch by Cocaine-Using MothersINFANCY, Issue 1 2003Pamela Schuetze Perceptual responses to infant distress signals were studied in 16 cocaine-using and 15 comparison mothers. All mothers rated tape recordings of 48 replications of a newborn infant's hunger cry digitally altered to increase in fundamental frequency in 100-Hz increments. Cries were rated on 4 perceptual (arousing, aversive, urgent, and sick) and 6 caregiving rating scale items (clean, cuddle, feed, give pacifier, pick up, and wait and see) used in previous studies. Analyses of variance showed that, as cry pitch increased, cries were rated as more arousing, aversive, and urgent sounding. The highest pitched cries received the highest ratings for caregiving interventions. Main effects for cocaine use showed cocaine-using mothers (a) rated cries as less arousing, aversive, urgent, and sick; (b) indicated they were less likely to pick up or feed the infant; and (c) indicated they more likely to give the crying infant a pacifier or just "wait and see." A Group x Cry Pitch interaction effect showed that mothers in the cocaine group gave higher ratings to wait and see as the pitch of the cries increased, whereas mothers in the comparison group gave lower ratings to wait and see as the pitch of the cries increased. These ratings indicate that cocaine-using mothers found cries to be less perceptually salient and less likely to elicit nurturant caregiving responses. These results suggest that maternal cocaine use is associated with altered perceptions of infant distress signals that may provide the basis for differential social responsivity in the caregiving context. [source] Perceptions of parent-child attachment, social self-efficacy, and peer relationships in middle childhoodINFANT AND CHILD DEVELOPMENT, Issue 4 2003Priscilla K. Coleman Abstract Relationships among attachment to each parent, children's social self-efficacy, and the quality of peer relations (attachment to peers and perceptions of victimization) were explored with 67 fifth and sixth graders (31 female) attending a rural elementary school. Results of hierarchical multiple regression analyses revealed main effects for gender and attachment to mother relative to the attachment to peers variable, with girls and more securely attached children reporting higher quality attachment to peers. Main effects were also detected for gender and attachment to father relative to social self-efficacy, with girls and more securely attached children exhibiting higher self-efficacy. No main effects were observed relative to the peer victimization variable. None of the interaction effects involving gender and attachment to each parent relative to attachment to peers, peer victimization, and social self-efficacy were significant. Finally, evidence for mediation of attachment to father on attachment to peers by children's social self-efficacy was revealed. Implications of the results are discussed and ideas for future research are provided. Copyright © 2003 John Wiley & Sons, Ltd. [source] Zolpidem Generalization and Antagonism in Male and Female Cynomolgus Monkeys Trained to Discriminate 1.0 or 2.0 g,/,kg EthanolALCOHOLISM, Issue 7 2008Christa M. Helms Background:, The subtypes of , -aminobutyric acid (GABA)A receptors mediating the discriminative stimulus effects of ethanol in nonhuman primates are not completely identified. The GABAA receptor positive modulator zolpidem has high, intermediate, and low activity at receptors containing ,1, ,2/3, and ,5 subunits, respectively, and partially generalizes from ethanol in several species. The partial inverse agonist Ro15-4513 has the greatest affinity for ,4/6 -containing receptors, higher affinity for ,5 - and lower, but equal, affinity for ,1 - and ,2/3 -, containing GABAA receptors, and antagonizes the discriminative stimulus effects of ethanol. Methods:, This study assessed Ro15-4513 antagonism of the generalization of zolpidem from ethanol in male (n = 9) and female (n = 8) cynomolgus monkeys (Macaca fascicularis) trained to discriminate 1.0 g/kg (n = 10) or 2.0 g/kg (n = 7) ethanol (i.g.) from water with a 30-minute pretreatment interval. Results:, Zolpidem (0.017 to 5.6 mg/kg, i.m.) completely generalized from ethanol (,80% of total session responses on the ethanol-appropriate lever) for 6/7 monkeys trained to discriminate 2.0 g/kg and 4/10 monkeys trained to discriminate 1.0 g/kg ethanol. Zolpidem partially generalized from 1.0 or 2.0 g/kg ethanol in 6/7 remaining monkeys. Ro15-4513 (0.003 to 0.30 mg/kg, i.m., 5-minute pretreatment) shifted the zolpidem dose,response curve to the right in all monkeys showing generalization. Analysis of apparent pKB from antagonism tests suggested that the discriminative stimulus effects of ethanol common with zolpidem are mediated by low-affinity Ro15-4513 binding sites. Main effects of sex and training dose indicated greater potency of Ro15-4513 in males and in monkeys trained to discriminate 1.0 g/kg ethanol. Conclusions:, Ethanol and zolpidem share similar discriminative stimulus effects most likely through GABAA receptors that contain ,1 subunits, however, antagonism by Ro15-4513 of zolpidem generalization from the lower training dose of ethanol (1.0 g/kg) may involve additional zolpidem-sensitive GABAA receptor subtypes (e.g., ,2/3 and ,5). [source] ARE HIGHLY STRUCTURED JOB INTERVIEWS RESISTANT TO DEMOGRAPHIC SIMILARITY EFFECTS?PERSONNEL PSYCHOLOGY, Issue 2 2010JULIE M. McCARTHY This study examines the extent to which highly structured job interviews are resistant to demographic similarity effects. The sample comprised nearly 20,000 applicants for a managerial-level position in a large organization. Findings were unequivocal: Main effects of applicant gender and race were not associated with interviewers' ratings of applicant performance nor was applicant,interviewer similarity with regard to gender and race. These findings address past inconsistencies in research on demographic similarity effects in employment interviews and demonstrate the value of using highly structured interviews to minimize the potential influence of applicant demographic characteristics on selection decisions. [source] An Experimental Test of the Theory of Planned BehaviorAPPLIED PSYCHOLOGY: HEALTH AND WELL-BEING, Issue 2 2009Falko Sniehotta The Theory of Planned Behavior (TPB) is one of the leading theories of health behavior, yet supporting evidence is exclusively based on correlational research. This study aims to test the TPB experimentally. N = 579 participants were randomised to receive persuasive messages addressing salient beliefs elicited in a pilot study, following a 2*2*2 factorial design. Participants were randomised to a behavioral-belief-intervention (BBI) or not, a normative-belief-intervention (NBI) or not, and a control-belief-intervention (CBI) or not. The primary outcome was objectively recorded attendance at university sports facilities over 2 months; and the secondary outcomes were post-intervention TPB measures. Main effects of the BBI on attitudes and of the NBI on subjective norm, PBC, attitudes, and intentions were found. The CBI did not alter post-intervention cognitions, but was the only intervention to change behavior not mediated by cognitions. While the findings support the TPB's assumptions on intention formation, behavior change results are not in line with the theory and therefore further question the TPB's leading role in behavioral science. [source] Risk of emotional disorder in offspring of depressed parents: gender differences in the effect of a second emotionally affected parentDEPRESSION AND ANXIETY, Issue 8 2008Karlien M.C. Landman-Peeters M.A. Abstract In offspring of depressed parents a second parent with emotional problems is likely to increase risk of emotional disorder. This effect may however differ between sons and daughters and between offspring of depressed fathers and offspring of depressed mothers. In adolescent and young-adult offspring of parents with major depressive disorder, this study examined the effects of a second affected parent, offspring gender, gender of the depressed parent and their interactions on risk of depression and anxiety disorder. We found that daughters had a higher risk of depression and anxiety than sons and that offspring of depressed mothers had a higher risk of anxiety than offspring of depressed fathers. In addition to these main effects, we found an interaction between parent and offspring gender inasmuch that sons of depressed fathers had the lowest risk of depression and anxiety relative to the other groups. A second affected parent tended to increase risk of depression and significantly increased risk of anxiety. However, this effect of a second affected parent on offspring anxiety was most prominent in daughters when the second affected parent was the father, whereas risk in sons did not increase if the father was affected as well. Our results indicate that paternal and maternal depression similarly and additively increase daughters' risk of emotional disorder, but that sons' risk only increases with maternal depression. Intergenerational transmission of emotional disorder seems strongest when the female gender is involved, either in the form of a daughter or a depressed mother. Depression and Anxiety 0:1,8, 2007. © 2007 Wiley-Liss, Inc. [source] Ghrelin: a new peptide regulating the neurohormonal system, energy homeostasis and glucose metabolismDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 5 2008Peter Pusztai Abstract Identification of ghrelin started with the discovery of growth hormone secretagogues, continued with the description of ghrelin receptors and ended with the elucidation of the chemical structure of ghrelin. However, several issues concerning the role of ghrelin in physiological and pathophysiological processes are still under investigation. Most of the ghrelin produced in the body is secreted in the stomach, but it is also expressed in the hypothalamus, pituitary, pancreas, intestine, kidney, heart and gonads. Ghrelin stimulates growth hormone secretion via growth hormone secretagogue receptors. Ghrelin secretion in the stomach depends on both acute and chronic changes in nutritional status and energy balance. Current data support the hypothesis that the stomach, in addition to its important role in digestion, not only influences pituitary hormone secretion but, via ghrelin production, it also sends orexigenic (appetite increasing) signals to hypothalamic nuclei involved in the regulation of energy homeostasis. In addition to these main effects, ghrelin influences insulin secretion and glucose metabolism and it may exert potentially important effects on cardiovascular and gastrointestinal functions. Because of its effects on a large number of physiological functions, ghrelin may be involved in the pathomechanism of several human disorders, including disturbances of appetite, energy homeostasis and glucose metabolism. Further research might lead to a better understanding of the pathophysiology of ghrelin and might provide more effective therapy for the above disorders. Copyright © 2008 John Wiley & Sons, Ltd. [source] Putting Rubrics to the Test: The Effect of a Model, Criteria Generation, and Rubric-Referenced Self-Assessment on Elementary School Students' WritingEDUCATIONAL MEASUREMENT: ISSUES AND PRACTICE, Issue 2 2008Heidi L. Andrade The purpose of this study was to investigate the effect of reading a model written assignment, generating a list of criteria for the assignment, and self-assessing according to a rubric, as well as gender, time spent writing, prior rubric use, and previous achievement on elementary school students' scores for a written assignment (N = 116). Participants were in grades 3 and 4. The treatment involved using a model paper to scaffold the process of generating a list of criteria for an effective story or essay, receiving a written rubric, and using the rubric to self-assess first drafts. The comparison condition involved generating a list of criteria for an effective story or essay, and reviewing first drafts. Findings include a main effect of treatment and of previous achievement on total writing scores, as well as main effects on scores for the individual criteria on the rubric. The results suggest that using a model to generate criteria for an assignment and using a rubric for self-assessment can help elementary school students produce more effective writing. [source] Extended treatment of older cigarette smokersADDICTION, Issue 6 2009Sharon M. Hall ABSTRACT Aims Tobacco dependence treatments achieve abstinence rates of 25,30% at 1 year. Low rates may reflect failure to conceptualize tobacco dependence as a chronic disorder. The aims of the present study were to determine the efficacy of extended cognitive behavioral and pharmacological interventions in smokers , 50 years of age, and to determine if gender differences in efficacy existed. Design Open randomized clinical trial. Setting A free-standing, smoking treatment research clinic. Participants A total of 402 smokers of , 10 cigarettes per day, all 50 years of age or older. Intervention Participants completed a 12-week treatment that included group counseling, nicotine replacement therapy (NRT) and bupropion. Participants, independent of smoking status, were then assigned randomly to follow-up conditions: (i) standard treatment (ST; no further treatment); (ii) extended NRT (E-NRT; 40 weeks of nicotine gum availability); (iii) extended cognitive behavioral therapy (E-CBT; 11 cognitive behavioral sessions over a 40-week period); or (iv) E-CBT plus E-NRT (E-combined; 11 cognitive behavioral sessions plus 40 weeks nicotine gum availability). Measurements Primary outcome variable was 7-day point prevalence cigarette abstinence verified biochemically at weeks 24, 52, 64 and 104. Findings The most clinically important findings were significant main effects for treatment condition, time and the treatment × time interaction. The E-CBT condition produced high cigarette abstinence rates that were maintained throughout the 2-year study period [(week 24 (58%), 52 (55%), 64 (55%) and 104 (55%)], and was significantly more effective than E-NRT and ST across that period. No other treatment condition was significantly different to ST. No effects for gender were found. Conclusions Extended cognitive behavioral treatments can produce high and stable cigarette abstinence rates for both men and women. NRT does not add to the efficacy of extended CBT, and may hamper its efficacy. Research is needed to determine if these results can be replicated in a sample with a greater range of ages, and improved upon with the addition of medications other than NRT. [source] Psychosocial outcomes in children two years after epilepsy surgery: Has anything changed?EPILEPSIA, Issue 4 2008Irene M. Elliott Summary Purpose: We prospectively explored psychosocial outcomes in children (7,18 years) 2 years after epilepsy surgery. This study built on our previous one that examined these children 1 year after surgery. Methods: Twenty children were studied using the Child Behavior Checklist (CBCL; a parent report instrument of potential behavioral and social problems) preoperatively, 1 year and 2 years after surgery. A comparison group of 12 children with medically refractory seizures was examined at comparable times. We conducted mixed factorial ANOVAs to determine group, time, and interaction effects, and regression analyses to assess factors driving significant (p , 0.05) interactions. We also investigated the proportion of children scoring in the abnormal range over time. Results: Significant main effects of time were observed on total behavior, externalizing, aggression, and delinquent behavior scales, with both groups reporting improvement. Main effects of group were observed for withdrawn and total competence scales, with the surgical group demonstrating favorable scores. Significant group × time interactions were observed on the social and social problems subscales. On both subscales, the surgical group demonstrated improvement over time, whereas the nonsurgical group experienced decline. Fifty percent of the surgical group remained seizure-free. Seizure status and number of antiepileptic medications predicted changes in social scores. We did not observe a significant regression model for the social problems subscale. Discussion: These findings suggest that change in social function may take time to develop after surgery. Prospective studies designed for longer periods are required to determine if improvements in other psychosocial domains are seen over time. [source] CLINICAL STUDY: A comparison of exposure to carcinogens among roll-your-own and factory-made cigarette smokersADDICTION BIOLOGY, Issue 3 2009Lion Shahab ABSTRACT Consumption of roll-your-own (RYO) tobacco is rising, but little is known about its in vivo delivery of toxins relative to factory-made (FM) cigarettes. To start to address this issue, this study compared the concentrations of metabolites of recognized human carcinogens in smokers of RYO tobacco and FM cigarettes. We opportunistically recruited 127 FM and 28 RYO cigarette smokers in central London and collected saliva and urine samples. Saliva samples were assayed for cotinine while urinary samples were assayed for 1-hydroxypyrene (1-HOP) and total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), metabolic markers of polycyclic aromatic hydrocarbons and tobacco-specific N -nitrosamines, respectively. Data on socio-demographic, anthropometric and puffing characteristics were also obtained. Both unadjusted and adjusted analyses (controlling for age, sex, body mass index, puff flow, puff duration and cotinine) showed no difference in metabolic markers between RYO and FM cigarette smokers. However, significant main effects for cotinine levels and sex were observed in adjusted analyses. Greater levels of cotinine were associated with a greater concentration of both 1-HOP (B = 0.002, P = 0.037) and NNAL (B = 0.002, P < 0.001). In addition, women had significantly greater concentrations of urinary 1-HOP (B = 0.679, P = 0.004) and total NNAL metabolites (B = 0.117, P = 0.024) than men, irrespective of the type of cigarettes smoked. More research is now needed to confirm these findings and gender-specific effects in a larger, representative sample. However, results do not support the common belief that RYO cigarettes are less harmful than manufactured cigarettes. [source] Personality, self-esteem, and self-construal as correlates of forgivingnessEUROPEAN JOURNAL OF PERSONALITY, Issue 1 2004Félix Neto The relationship between forgivingness (enduring resentment, sensitivity to circumstances, and overall propensity to forgive) and a number of personality dimensions relevant to forgivingness was examined. These dimensions were self-esteem, shyness and embarrassment, on one hand, and self-construal and perceived loneliness, on the other hand. The main relationships between forgivingness and personality concerned the interpersonal dimensions of personality: shyness, embarrassment, independence from others, and interdependence with others. However, the intra-personal, strictly self-referential concomitants of these dimensions (self-esteem and loneliness) were not much linked to forgivingness. Furthermore, each personality factor had a distinct link with forgivingness: independence made the resentment still more enduring, shyness and social embarrassment exacerbated the sensitivity to circumstances, and interdependence increased the willingness to forgive. These findings throw light on the double aspect of forgiveness as intra- and inter-individual and on the relative independence of these aspects. The observed pattern of relationships varied notably (and significantly) as a function of the participants' genders. It could be therefore important, in future studies, to compute systematically correlation coefficients or assess main effects separately for women and men. Copyright © 2003 John Wiley & Sons, Ltd. [source] Impact of the fish Garra on the ecology of reservoirs and the occurrence of Microcystis blooms in semi-arid tropical highlands: an experimental assessment using enclosuresFRESHWATER BIOLOGY, Issue 8 2009TADESSE DEJENIE Summary 1.,Many man-made reservoirs in the semi-arid highlands of Northern Ethiopia (Tigray) are characterised by the occurrence of intensive blooms of cyanobacteria and a dominance of small riverine fishes belonging to the genus Garra. 2.,We carried out enclosure experiments to test for the effect of these small fish on abiotic characteristics, phytoplankton biomass and zooplankton community structure in the pelagic of two reservoirs (Gereb Awso and Tsinkanet). Two experiments were carried out in each of the reservoirs, one at the end of the rainy season (highest water level) and one at the end of the dry season (lowest water level). 3.,The presence of Garra in general increased the amount of suspended matter, nutrient concentrations (total nitrogen and total phosphorus), phytoplankton and Microcystis biomass (including the proportion of Microcystis in the phytoplankton community), and reduced water transparency. The positive effect of the presence of Garra on nutrient concentrations and phytoplankton productivity indicate that Garra has the potential to affect food web functioning indirectly through bottom-up effects, by enhancing nutrient concentrations through sediment resuspension and excretion of nutrients. Indeed, population densities of the cladoceran zooplankton taxa Ceriodaphnia and Diaphanosoma also showed an overall increase in enclosures with Garra. 4.,However, our data also provide some evidence for a potential of Garra to exert top-down control on large bodied daphnids (Daphnia carinata, D. barbata), although such effect varied among experiments. The limited capability of Garra to control zooplankton communities mainly reflects the low efficiency of these small, riverine and benthos-oriented fish in foraging on zooplankton and suggests the existence of an unoccupied niche for zooplanktivorous fish in the majority of the reservoirs. 5.,Although the main effects of Garra on the pelagic food web seemed to be mediated by bottom-up mechanisms, our results also indicate that one of the key variables, the relative abundance of Microcystis, was impacted by Daphnia -mediated trophic cascade effects. [source] Tryptophan hydroxylase 1 gene haplotypes modify the effect of a hostile childhood environment on adulthood harm avoidanceGENES, BRAIN AND BEHAVIOR, Issue 4 2007L. Keltikangas-Järvinen We conducted a series of tests to determine whether there is any association between tryptophan hydroxylase 1 (TPH1) and temperament in adulthood. In addition to testing for main effects, we investigated whether TPH1 gene variation modifies the influence of childhood environment on temperament in adulthood. The subjects were 341 healthy adults whose childhood environment was assessed by their mothers in 1980 and who self-rated their temperaments twice, in 1997 and 2001. We found no association between the TPH1 gene and temperament; however, among women, the TPH1 gene modified a relationship between adverse childhood environment and harm avoidance in adulthood. This finding was confirmed in the same sample in another test setting 4 years later. The presence of the A/A haplotype of the TPH1 intron 7 A218A and A779C polymorphism predicted a high level of adulthood harm avoidance in the presence of a hostile childhood environment as defined in terms of emotional rejection, maternal neglect and harsh and inconsistent discipline. In addition, the findings suggest a gene,environment correlation for novelty seeking in men. [source] Genetic association tests in the presence of epistasis or gene-environment interactionGENETIC EPIDEMIOLOGY, Issue 7 2008Kai WangArticle first published online: 24 APR 200 Abstract A genetic variant is very likely to manifest its effect on disease through its main effect as well as through its interaction with other genetic variants or environmental factors. Power to detect genetic variants can be greatly improved by modeling their main effects and their interaction effects through a common set of parameters or "generalized association parameters" (Chatterjee et al. [2006] Am. J. Hum. Genet. 79:1002,1016) because of the reduced number of degrees of freedom. Following this idea, I propose two models that extend the work by Chatterjee and colleagues. Particularly, I consider not only the case of relatively weak interaction effect compared to the main effect but also the case of relatively weak main effect. This latter case is perhaps more relevant to genetic association studies. The proposed methods are invariant to the choice of the allele for scoring genotypes or the choice of the reference genotype score. For each model, the asymptotic distribution of the likelihood ratio statistic is derived. Simulation studies suggest that the proposed methods are more powerful than existing ones under certain circumstances. Genet. Epidemiol. 2008. © 2008 Wiley-Liss, Inc. [source] A novel method to identify gene,gene effects in nuclear families: the MDR-PDTGENETIC EPIDEMIOLOGY, Issue 2 2006E.R. Martin Abstract It is now well recognized that gene,gene and gene,environment interactions are important in complex diseases, and statistical methods to detect interactions are becoming widespread. Traditional parametric approaches are limited in their ability to detect high-order interactions and handle sparse data, and standard stepwise procedures may miss interactions that occur in the absence of detectable main effects. To address these limitations, the multifactor dimensionality reduction (MDR) method [Ritchie et al., 2001: Am J Hum Genet 69:138,147] was developed. The MDR is wellsuited for examining high-order interactions and detecting interactions without main effects. The MDR was originally designed to analyze balanced case-control data. The analysis can use family data, but requires a single matched pair be selected from each family. This may be a discordant sib pair, or may be constructed from triad data when parents are available. To take advantage of additional affected and unaffected siblings requires a test statistic that measures the association of genotype with disease in general nuclear families. We have developed a novel test, the MDR-PDT, by merging the MDR method with the genotype-Pedigree Disequilibrium Test (geno-PDT)[Martin et al., 2003: Genet Epidemiol 25:203,213]. MDR-PDT allows identification of single-locus effects or joint effects of multiple loci in families of diverse structure. We present simulations to demonstrate the validity of the test and evaluate its power. To examine its applicability to real data, we applied the MDR-PDT to data from candidate genes for Alzheimer disease (AD) in a large family dataset. These results show the utility of the MDR-PDT for understanding the genetics of complex diseases. Genet. Epidemiol. 2006. © 2005 Wiley-Liss, Inc. [source] Embedded Shape-Memory Alloy Wires for Improved Performance of Self-Healing Polymers,ADVANCED FUNCTIONAL MATERIALS, Issue 15 2008Eva L. Kirkby Abstract We report the first measurements of self-healing polymers with embedded shape-memory alloy (SMA) wires. The addition of SMA wires shows improvements of healed peak fracture loads by up to a factor of 1.6, approaching the performance of the virgin material. Moreover, the repairs can be achieved with reduced amounts of healing agent. The improvements in performance are due to two main effects: (i) crack closure, which reduces the total crack volume and increases the crack fill factor for a given amount of healing agent and (ii) heating of the healing agent during polymerization, which increases the degree of cure of the polymerized healing agent. [source] Permutation tests for factorially designed neuroimaging experimentsHUMAN BRAIN MAPPING, Issue 3 2004John Suckling Abstract Permutation methods for analysis of functional neuroimaging data acquired as factorially designed experiments are described and validated. The F ratio was estimated for main effects and interactions at each voxel in standard space. Critical values corresponding to probability thresholds were derived from a null distribution sampled by appropriate permutation of observations. Spatially informed, cluster-level test statistics were generated by applying a preliminary probability threshold to the voxel F maps and then computing the sum of voxel statistics in each of the resulting three-dimensional clusters, i.e., cluster "mass." Using simulations comprising two between- or within-subject factors each with two or three levels, contaminated by Gaussian and non-normal noise, the voxel-wise permutation test was compared to the standard parametric F test and to the performance of the spatially informed statistic using receiver operating characteristic (ROC) curves. Validity of the permutation-testing algorithm and software is endorsed by almost identical performance of parametric and permutation tests of the voxel-level F statistic. Permutation testing of suprathreshold voxel cluster mass, however, was found to provide consistently superior sensitivity to detect simulated signals than either of the voxel-level tests. The methods are also illustrated by application to an experimental dataset designed to investigate effects of antidepressant drug treatment on brain activation by implicit sad facial affect perception in patients with major depression. Antidepressant drug effects in left amygdala and ventral striatum were detected by this software for an interaction between time (within-subject factor) and group (between-subject factor) in a representative two-way factorial design. Hum. Brain Mapping 22:193,205, 2004. © 2004 Wiley-Liss, Inc. [source] Effects of dietary caffeine on EEG, performance and mood when rested and sleep restricted,HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 8 2008Michael A. Keane Abstract Rationale: Until recently, little account had been taken of the confounding effects of caffeine withdrawal and withdrawal reversal when examining the net effects of dietary caffeine. Objectives: By including a manipulation involving sleep restriction, the present study aimed to extend recent findings from research in which caffeine withdrawal and withdrawal reversal were controlled. The main aims of the study were to examine the net effects of caffeine, as well as its potential restorative effects following sleep restriction, on EEG, performance and mood. Method: A randomised cross-over design was used in which 15 participants alternated weekly between ingesting placebo and caffeine (1.75,mg/kg) three times daily for four consecutive weeks following either usual sleep or sleep restriction. EEG activity was measured at 32 sites during eyes closed, eyes open and performance of a vigilance task. Results: Modest effects of caffeine were found in the delta and beta bandwidths, but no main effects of caffeine were observed in the theta or alpha bandwidths. Overall, the effects of caffeine on EEG activity were relatively few, weak and inconsistent, and no evidence was found of net restorative effects of caffeine for any outcome variables. Conclusions: The findings do not support the use of caffeine as a means for enhancing human function or as an antidote to the negative effects of sleep loss. Copyright © 2008 John Wiley & Sons, Ltd. [source] HRM as a predictor of innovationHUMAN RESOURCE MANAGEMENT JOURNAL, Issue 1 2006Helen Shipton There is growing evidence available to suggest that HR practice is an important predictor of organisational performance. In this article, we argue that HR practices also have the potential to promote organisational innovation. We describe a longitudinal study of 22 UK manufacturing companies and examine the relationship between such practices and product and technological innovation. Results reveal that training, induction, team working, appraisal and exploratory learning focus are all predictors of innovation. Contingent reward, applied in conjunction with an exploratory learning focus, is positively associated with innovation in technical systems. Furthermore, training, appraisal and induction, combined with exploratory learning focus, explain variation between companies in product and technological innovation above and beyond the main effects observed. [source] What aspects of the job have most effect on nurses?HUMAN RESOURCE MANAGEMENT JOURNAL, Issue 1 2003Abraham Sagie The study reported here compared the influences of psychological constructs (job demands and scheduling control) and objective work characteristics (shiftwork, night-work and hospital department type) on job satisfaction, organisational commitment, burnout and withdrawal intentions. Our hypothesis was that psychological constructs have a higher influence on work-related attitudes than objective characteristics of work schedules. In addition to the main effects, we proposed an interactive hypothesis: poor attitudes would result from high demands and low control rather than from other combinations of both psychological variables. Using a sample of 153 hospital nurses in Israel, the hypotheses were generally supported. As night-work, shiftwork and working in intensive care units are unavoidable characteristics of the modern medical environment, these findings are meaningful for improving the personal adjustment of hospital nurses. [source] Tidal Barrages and BirdsIBIS, Issue 2006NIGEL A. CLARK This paper reviews the main effects that building tidal power barrages would have on the bird populations using Britain's estuaries. The changes in the tidal prism that would occur after a tidal power barrage is built are discussed in the context of their effect on the ecology of the estuary. Three main issues are discussed; the effect of changes in size and nature of the intertidal areas of the estuary, effects on saltmarshes, and the displacement of birds at closure. Recently, tidal stream technologies have been developed which are individually likely to have small effects on birds. However the cumulative effects of large scale tidal stream arrays need to be investigated. Finally, the effects of tidal barrages are put in the context of Britain's energy policy and the need to reduce greenhouse gas emissions. Should tidal power barrages be considered in the future, there will be a need for strategic assessments to be used to select sites that maximize the energy produced while minimizing the impacts on bird populations. [source] The Meaning of Employee EngagementINDUSTRIAL AND ORGANIZATIONAL PSYCHOLOGY, Issue 1 2008WILLIAM H. MACEY The meaning of employee engagement is ambiguous among both academic researchers and among practitioners who use it in conversations with clients. We show that the term is used at different times to refer to psychological states, traits, and behaviors as well as their antecedents and outcomes. Drawing on diverse relevant literatures, we offer a series of propositions about (a) psychological state engagement; (b) behavioral engagement; and (c) trait engagement. In addition, we offer propositions regarding the effects of job attributes and leadership as main effects on state and behavioral engagement and as moderators of the relationships among the 3 facets of engagement. We conclude with thoughts about the measurement of the 3 facets of engagement and potential antecedents, especially measurement via employee surveys. [source] Perceptions of parent-child attachment, social self-efficacy, and peer relationships in middle childhoodINFANT AND CHILD DEVELOPMENT, Issue 4 2003Priscilla K. Coleman Abstract Relationships among attachment to each parent, children's social self-efficacy, and the quality of peer relations (attachment to peers and perceptions of victimization) were explored with 67 fifth and sixth graders (31 female) attending a rural elementary school. Results of hierarchical multiple regression analyses revealed main effects for gender and attachment to mother relative to the attachment to peers variable, with girls and more securely attached children reporting higher quality attachment to peers. Main effects were also detected for gender and attachment to father relative to social self-efficacy, with girls and more securely attached children exhibiting higher self-efficacy. No main effects were observed relative to the peer victimization variable. None of the interaction effects involving gender and attachment to each parent relative to attachment to peers, peer victimization, and social self-efficacy were significant. Finally, evidence for mediation of attachment to father on attachment to peers by children's social self-efficacy was revealed. Implications of the results are discussed and ideas for future research are provided. Copyright © 2003 John Wiley & Sons, Ltd. [source] The Usefulness of Design of Experimentation in Defining the Effect Difficult Airway Factors and Training Have on Simulator Oral,Tracheal Intubation Success Rates in Novice IntubatorsACADEMIC EMERGENCY MEDICINE, Issue 4 2010Frank Thomas MD Abstract Objectives:, This exploratory study examined novice intubators and the effect difficult airway factors have on pre- and posttraining oral,tracheal simulation intubation success rates. Methods:, Using a two-level, full-factorial design of experimentation (DOE) involving a combination of six airway factors (curved vs. straight laryngoscope blade, trismus, tongue edema, laryngeal spasm, pharyngeal obstruction, or cervical immobilization), 64 airway scenarios were prospectively randomized to 12 critical care nurses to evaluate pre- and posttraining first-pass intubation success rates on a simulator. Scenario variables and intubation outcomes were analyzed using a generalized linear mixed-effects model to determine two-way main and interactive effects. Results:, Interactive effects between the six study factors were nonsignificant (p = 0.69). For both pre- and posttraining, main effects showed the straight blade (p = 0.006), tongue edema (p = 0.0001), and laryngeal spasm (p = 0.004) significantly reduced success rates, while trismus (p = 0.358), pharyngeal obstruction (p = 0.078), and cervical immobilization did not significantly change the success rate. First-pass intubation success rate on the simulator significantly improved (p = 0.005) from pre- (19%) to posttraining (36%). Conclusions:, Design of experimentation is useful in analyzing the effect difficult airway factors and training have on simulator intubation success rates. Future quality improvement DOE simulator research studies should be performed to help clarify the relationship between simulator factors and patient intubation rates. ACADEMIC EMERGENCY MEDICINE 2010; 17:460,463 © 2010 by the Society for Academic Emergency Medicine [source] Neuroticism and conscientiousness as predictors of emotional, external, and restrained eating behaviorsINTERNATIONAL JOURNAL OF EATING DISORDERS, Issue 2 2001Patrick C.L. Heaven Abstract Objective We investigated the extent to which different forms of eating behavior as assessed by the Dutch Eating Behaviour Questionnaire are related to facets of the Big Five personality domains. Method Respondents were 167 psychology students (126 females and 41 males) who volunteered for the study. Results Body mass index (BMI) and gender had significant main effects on eating behaviors. These results were moderated by a significant BMI × Gender interaction on emotional eating. Eating behaviors were significantly related to the personality facets associated with Neuroticism and Conscientiousness. Discussion The results are discussed with reference to previous research on eating behaviors and the nature of Neuroticism and Conscientiousness. © 2001 by John Wiley & Sons, Inc. Int J Eat Disord 30: 161,166, 2001. [source] Fat, wheat bran and salt effects on cooking properties of meat patties studied by response surface methodologyINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 10 2010Hasibe Tekin Summary Response surface methodology was used to investigate the main effects and interactions of composition (processing) variables such as fat (10,30%), wheat bran (5,15%) and NaCl (0,2%) on cooking properties of beef patties. In addition, the ridge analysis was conducted to find the values of processing variables that maximise and minimise the cooking parameters (moisture retention, fat retention, reduction in thickness, reduction in diameter, cooking yield, shrinkage and water-holding capacity). It was found that the moisture and fat retention, reduction in thickness and cooking yield values decreased; however, reduction in diameter and shrinkage values increased, respectively, as the amount of fat increased. However, wheat bran addition increased fat retention, moisture retention, cooking yield and water-holding capacity values of the patties. Increasing NaCl levels decreased water-holding capacity value by its quadratic effect and moisture and fat retention value by its interaction effect with wheat bran. [source] Subtle deficits of attention after surgery: quantifying indicators of sub syndrome deliriumINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 10 2010David Peter Lowery Abstract Objective To determine whether attentional impairments are reliable neuropsychological markers of sub syndrome delirium. Method A prospective cohort study with repeated assessment beginning pre-operatively and continuing through the first post-operative week. Computerized assessments of attention and the Mini-Mental State Examination were administered with one hundred patients admitted for elective orthopedic surgery, 70 years and over and free of dementia. Acute change of cognitive status was used to identify cases of sub syndrome delirium. Results There were significant differences of post-surgical performance between the ,no delirium' and ,sub-syndrome delirium' groups of reaction time, global cognition, accuracy and greater variability of reaction time (p,<,0.041). There were significant within subject main effects on reaction time (p,=,0.001), variability of reaction time (p,=,0.022) and MMSE (p,=,0.000) across the cohort; but no significant interaction effect of ,diagnosis' * ,time' on the computerized measures of attention (p,>,0.195). Conclusion The distinction between people with sub syndrome delirium and no delirium is difficult to quantify but computerized measures of attention might provide a sensitive indicator. Sub syndrome delirium is an observable marker of a clinical abnormality that should be exploited to improve care management for vulnerable patients. Copyright © 2010 John Wiley & Sons, Ltd. [source] Association chain graphs: modelling etiological pathwaysINTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 2 2003Michael Höfler Abstract Multiple time-dynamic and interrelated risk factors are usually involved in the complex etiology of disorders. This paper presents a strategy to explore and display visually the relative importance of different association pathways for the onset of disorder over time. The approach is based on graphical chain models, a tool that is powerful but still under-utilized in most fields. Usually, the results of these models are displayed using directed acyclic graphs (DAGs). These draw an edge between a pair of variables whenever the assumption of conditional independence given variables on an earlier or equal temporal footing is violated to a statistically significant extent. In the present paper, the graphs are modified in that confidence intervals for the strengths of associations (statistical main effects) are visualized. These new graphs are called association chain graphs (ACGs). Statistical interactions cause ,edges' between the respective variables within the DAG framework (because the assumption of conditional independence is violated). In contrast they are represented as separate graphs within the subsample where the different association chains may work within the ACG framework. With this new type of graph, more specific information can be displayed whenever the data are essentially described only with statistical main- and two-way interaction effects. Copyright © 2003 Whurr Publishers Ltd. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||