Showing papers by "University of Windsor published in 2008"

Initial severity and antidepressant benefits: a meta-analysis of data submitted to the Food and Drug Administration.

Abstract: Background Meta-analyses of antidepressant medications have reported only modest benefits over placebo treatment, and when unpublished trial data are included, the benefit falls below accepted criteria for clinical significance. Yet, the efficacy of the antidepressants may also depend on the severity of initial depression scores. The purpose of this analysis is to establish the relation of baseline severity and antidepressant efficacy using a relevant dataset of published and unpublished clinical trials. Methods and Findings We obtained data on all clinical trials submitted to the US Food and Drug Administration (FDA) for the licensing of the four new-generation antidepressants for which full datasets were available. We then used meta-analytic techniques to assess linear and quadratic effects of initial severity on improvement scores for drug and placebo groups and on drug–placebo difference scores. Drug–placebo differences increased as a function of initial severity, rising from virtually no difference at moderate levels of initial depression to a relatively small difference for patients with very severe depression, reaching conventional criteria for clinical significance only for patients at the upper end of the very severely depressed category. Meta-regression analyses indicated that the relation of baseline severity and improvement was curvilinear in drug groups and showed a strong, negative linear component in placebo groups.

Identifying discriminating variables between teachers who fully integrate computers and teachers with limited integration

Abstract: Given the prevalence of computers in education today, it is critical to understand teachers' perspectives regarding computer integration in their classrooms The current study surveyed a random sample of a heterogeneous group of 185 elementary and 204 secondary teachers in order to provide a comprehensive summary of teacher characteristics and variables that best discriminate between teachers who integrate computers and those who do not Discriminant Function Analysis indicated seven variables for elementary teachers and six for secondary teachers (accounting for 74% and 68% of the variance, respectively) that discriminated between high and low integrators Variables included positive teaching experiences with computers; teacher's comfort with computers; beliefs supporting the use of computers as an instructional tool; training; motivation; support; and teaching efficacy Implications for support of computer integration in the classroom are discussed

Aerodynamic models for Darrieus-type straight-bladed vertical axis wind turbines

Abstract: Since ancient past humans have attempted to harness the wind energy through diversified means and vertical axis wind turbines (VAWTs) were one of the major equipment to achieve that. In this modern time, there is resurgence of interests regarding VAWTs as numerous universities and research institutions have carried out extensive research activities and developed numerous designs based on several aerodynamic computational models. These models are crucial for deducing optimum design parameters and also for predicting the performance before fabricating the VAWT. In this review, the authors have attempted to compile the main aerodynamic models that have been used for performance prediction and design of straight-bladed Darrieus-type VAWT. It has been found out that at present the most widely used models are the double-multiple streamtube model, Vortex model and the Cascade model. Each of these three models has its strengths and weaknesses which are discussed in this paper.

Single molecule analysis by surfaced-enhanced Raman scattering

Abstract: Our main objective in this tutorial review is to provide insight into some of the questions surrounding single molecule detection (SMD) using surface-enhanced Raman scattering (SERS) and surface-enhanced resonance Raman scattering (SERRS). Discovered thirty years ago, SERS is now a powerful analytical tool, strongly tied to plasmonics, a field that encompasses and profits from the optical enhancement found in nanostructures that support localized plasmon excitations. The spectrum of the single molecule carries the quantum fingerprints of the system modulated by the molecule-nanostructure interactions and the electronic resonances that may result under laser excitation. This information is embedded in vibrational band parameters. The dynamics and the molecular environment will affect the bandwidth of the observed Raman bands. In addition, the localized surface plasmon resonances (LSPR) empower the nanostructure with a number of optical properties that will also leave their mark on the observed inelastic scattering process. Therefore, controlling size, shape and the formation of the aggregation state (or fractality) of certain metallic nanostructures becomes a main task for experimental SERS/SERRS. This molecule-nanostructure coupling may, inevitably, lead to spectral fluctuations, increase photobleaching or photochemistry. An attempt is made here to guide the interpretation of this wealth of information when approaching the single molecule regime.

Neuropsychological Outcome in Adolescents/Young Adults with Childhood ADHD: Profiles of Persisters, Remitters and Controls

Abstract: The behavioral phenotype of attention-deficit/hyperactivity disorder (ADHD) changes in characteristic ways, with a tendency for symptom improvement and at least partial recovery throughout development. Studies of children with ADHD followed into adolescence and adulthood indicate that 20–50% improve with regard to ADHD symptoms and no longer meet criteria for the disorder (Barkley, Fischer, Edelbrock, & Smallish, 1990; Biederman, Mick, & Faraone, 2000; Hill & Schoener, 1996). In addition, the nature of the symptoms change over development; hyperactivity-impulsivity is most apparent during the younger ages, whereas inattention and related dysfunction is most prominent during later developmental stages (Hart, Lahey, Loeber, Applegate, & Frick, 1995). Consistent with the behavioral heterogeneity in ADHD is the wide range of neurocognitive heterogeneity (Nigg, Willcutt, Doyle, & Sonuga-Barke, 2005). Despite the common conceptualization of ADHD as a disorder of executive functions (EFs) subserved by frontal-subcortical neural systems (Barkley, 1997), recent meta-analyses (Frazier, Demaree, & Youngstrom, 2004; van Mourik, Oosterlaan, & Sergeant, 2005; Willcutt, Doyle, Nigg, Faraone, & Pennington, 2005) indicate an array of executive and non-executive function deficits in children with ADHD. Furthermore, increased variability in reaction time (RT) is rapidly emerging as one of the most consistent deficits in children with ADHD (Castellanos & Tannock, 2002; Russell et al., 2006). Additional presumably “non-executive” parameters have been shown to differentiate ADHD from non-ADHD children, including signal detectability (d′) and response bias (lnβ) variables from continuous performance tests (CPTs; Losier, McGrath, & Klein, 1996). Kuntsi and colleagues (2001) reported that RT variability discriminated ADHD children from controls better than measures of inhibition and working memory, and Epstein and colleagues (2003) reported variability in d′, lnβ, and RT to be strongly associated across multiple ADHD symptom domains. As such, it has been hypothesized that the EF deficits frequently observed in children with ADHD may be due to deficiencies in largely subcortical, regulatory systems, rather than cortical EF circuitry per se (Douglas, 1999; Rommelse et al., 2007; Sergeant, Oosterlaan, & van der Meere, 1999; Sonuga-Barke & Castellanos, 2007). A smaller literature has examined neuropsychological deficits in adults with ADHD (Nigg et al., 2005; Seidman, 2006) with findings generally indicating impairments similar to those in children. A recent meta-analysis (Hervey, Epstein, & Curry, 2004) reported that, compared to controls, adults with ADHD performed worse across multiple neuropsychological domains. Consistent impairments on various CPT paradigms were reported, whereas more traditional EF tests such as the Stroop, Wisconsin Card Sorting Test (WCST), and Trail-Making Test only differentiated the groups moderately well, if at all (Hervey et al., 2004; Nigg et al., 2005; Seidman, 2006). While it is important to determine which neurocognitive deficits are present in adults with persistent ADHD, it is equally important to understand the degree to which improvement in specific neurocognitive functions is associated with recovery. Carr, Nigg and Henderson (2006) reasoned that core deficits of ADHD should persist in adults who no longer meet criteria for the disorder, but more epiphenomenal characteristics should parallel symptom recovery. They compared adults with ADHD, adults with retrospectively-assessed childhood histories of ADHD but partial recovery, and controls using an antisaccade task which evaluated distinct forms of inhibition. Directional errors on the task fit the pattern of epiphenomenal symptoms in that the ADHD group, but not the partially remitted group, differed from controls. In contrast, anticipatory errors behaved more like a core deficit; those with childhood ADHD differed from controls irrespective of adult status. This approach provides insight into the developmental trajectory of neurocognitive functioning in ADHD and the dissociation of potentially causal versus secondary deficits. Yet, retrospective recall of childhood ADHD symptoms and impairment is often inaccurate (Mannuzza, Klein, Klein, Bessler, & Shrout, 2002). As such, these kinds of questions are best addressed in a longitudinal sample. Drechsler et al. (2005) examined measures of alertness and inhibitory control in controls and children with ADHD (mean age = 11.0 at baseline) three times over 2.6 years. By the final assessment, there were no group differences on their measures. However, these findings are difficult to interpret because 61% of their ADHD group no longer met criteria for the disorder at the final follow-up assessment and data were not examined relative to persistence/remittance. Other longitudinal studies of children with ADHD followed into adolescence and beyond have generally found that neuropsychological dysfunction is prominent throughout development (Fischer, Barkley, Edelbrock, & Smallish, 1990). Seidman and colleagues (1997) reported deficits on the Stroop, WCST, and an auditory CPT among high school and college-age participants diagnosed with ADHD in childhood. However, they did not examine whether task performance varied as a function of ADHD persistence. Fischer and colleagues (2005) examined neuropsychological outcomes of childhood ADHD relative to the presence or absence of ADHD at early adult follow-up. Those with persistent ADHD made significantly more omission and commission errors on a CPT than controls, while those with ADHD in childhood, but not adulthood (i.e., remitters), did not differ from either group on these measures. Persisters, remitters and controls earned similar amounts on a card task designed to measure inhibitory control, although both ADHD groups performed the task slower than controls. To explain developmental changes associated with ADHD across the lifespan, Halperin and Schulz (2006) posited distinct neurocognitive mechanisms for the etiology of and recovery from ADHD. They hypothesized that ADHD is caused by non-cortical neural dysfunction that is present early in ontogeny, remains relatively static throughout life, and is not associated with the reduction of symptoms typically seen over development. Rather, variations in the diminution of symptoms with increasing age are accounted for by the degree to which prefrontally-mediated EFs, which emerge throughout childhood and adolescence, can compensate for more primary and enduring subcortical deficits. According to this model, performance of adults who had ADHD in childhood, on measures which reflect executive control, should closely parallel their present symptom severity. In contrast, measures of more automatic or less consciously-controlled processes should be linked to the presence of ADHD in childhood, irrespective of later clinical status. This study examined neuropsychological functioning in a longitudinal sample of adolescents/young adults who were diagnosed with ADHD in childhood as compared to a never-ADHD control group. We hypothesized that those with childhood ADHD would perform more poorly than controls on a diverse neuropsychological test battery. Further, we examined the degree to which performance on measures requiring high levels of executive processing would parallel adolescent clinical status, such that ADHD-Persisters, but not ADHD-Remitters would differ from controls. In contrast, Persisters and Remitters were hypothesized to perform more similarly, and different from controls, on measures that reflect behaviors that are unlikely to be under executive control.

Photoferrotrophs thrive in an Archean Ocean analogue

Abstract: Considerable discussion surrounds the potential role of anoxygenic phototrophic Fe(II)-oxidizing bacteria in both the genesis of Banded Iron Formations (BIFs) and early marine productivity. However, anoxygenic phototrophs have yet to be identified in modern environments with comparable chemistry and physical structure to the ancient Fe(II)-rich (ferruginous) oceans from which BIFs deposited. Lake Matano, Indonesia, the eighth deepest lake in the world, is such an environment. Here, sulfate is scarce ( 100-m-deep chemocline. Within this sulfide-poor, Fe(II)-rich, illuminated chemocline, we find a populous assemblage of anoxygenic phototrophic green sulfur bacteria (GSB). These GSB represent a large component of the Lake Matano phototrophic community, and bacteriochlorophyll e, a pigment produced by low-light-adapted GSB, is nearly as abundant as chlorophyll a in the lake's euphotic surface waters. The dearth of sulfide in the chemocline requires that the GSB are sustained by phototrophic oxidation of Fe(II), which is in abundant supply. By analogy, we propose that similar microbial communities, including populations of sulfate reducers and photoferrotrophic GSB, likely populated the chemoclines of ancient ferruginous oceans, driving the genesis of BIFs and fueling early marine productivity. anoxygenic photosynthesis banded iron formation green sulfur bacteria iron oxidation Lake Matano

Entry into Elite Sport: A Preliminary Investigation into the Transition Experiences of Rookie Athletes

Abstract: Athletes experience a number of transitions throughout their athletic career (Wylleman, Alfermann, & Lavallee, 2004). One pivotal transition that has received less attention in the literature is the transition into elite sport. The purpose of the present study was to examine the transitioning experience of young athletes entering elite sport. Using a phenomenological approach, rookie ice hockey players (N = 8, representing two different Major Junior ‘A’ teams) were asked about their experiences of entering into elite sport. Two primary themes emerged from the young athletes’ responses: on-ice issues associated with performance and off-ice issues relating to relationships and personal development. These findings offer preliminary evidence that young athletes encounter transitional challenges during the entry into elite sport. Further research is necessary to explore how the entry experience impacts young athletes’ athletic and psychosocial development and well-being.

A Season-Long Team-Building Intervention: Examining the Effect of Team Goal Setting on Cohesion

Abstract: The purpose of the current study was to determine whether the implementation of a season-long team-building intervention program using team goal setting increased perceptions of cohesion. The participants were 86 female high school basketball players from 8 teams. The teams were randomly assigned to either an experimental team goal–setting or control condition. Each participant completed the Group Environment Questionnaire (GEQ; Carron, Brawley, & Widmeyer, 2002; Carron, Widmeyer, & Brawley, 1985), which assessed cohesion at both the beginning and end of the season. Overall, the results revealed a significant multi variate effect, Pillai’s trace F(12, 438) = 2.68, p = .002. Post hoc analyses showed that at the beginning of the season, athletes from both conditions did not differ in their perceptions of cohesion. However, at the end of the season, athletes in the team goal–setting condition held higher perceptions of cohesion than athletes in the control condition. Overall, the results indicated that team goal setting was an effective team-building tool for influencing cohesiveness in sport teams.

Identifying the source of species invasions: sampling intensity vs. genetic diversity

Abstract: Population geneticists and community ecologists have long recognized the importance of sampling design for uncovering patterns of diversity within and among populations and in communities. Invasion ecologists increasingly have utilized phylogeographical patterns of mitochondrial or chloroplast DNA sequence variation to link introduced populations with putative source populations. However, many studies have ignored lessons from population genetics and community ecology and are vulnerable to sampling errors owing to insufficient field collections. A review of published invasion studies that utilized mitochondrial or chloroplast DNA markers reveals that insufficient sampling could strongly influence results and interpretations. Sixty per cent of studies sampled an average of less than six individuals per source population, vs. only 45% for introduced populations. Typically, far fewer introduced than source populations were surveyed, although they were sampled more intensively. Simulations based on published data forming a comprehensive mtDNA haplotype data set highlight and quantify the impact of the number of individuals surveyed per source population and number of putative source populations surveyed for accurate assignment of introduced individuals. Errors associated with sampling a low number of individuals are most acute when rare source haplotypes are dominant or fixed in the introduced population. Accuracy of assignment of introduced individuals is also directly related to the number of source populations surveyed and to the degree of genetic differentiation among them (F(ST)). Incorrect interpretations resulting from sampling errors can be avoided if sampling design is considered before field collections are made.

First Penning-trap mass measurement of the exotic halo nucleus 11Li.

Abstract: In this Letter, we report a new mass for {sup 11}Li using the trapping experiment TITAN at TRIUMF's ISAC facility. This is by far the shortest-lived nuclide, t{sub 1/2}=8.8 ms, for which a mass measurement has ever been performed with a Penning trap. Combined with our mass measurements of {sup 8,9}Li we derive a new two-neutron separation energy of 369.15(65) keV: a factor of 7 more precise than the best previous value. This new value is a critical ingredient for the determination of the halo charge radius from isotope-shift measurements. We also report results from state-of-the-art atomic-physics calculations using the new mass and extract a new charge radius for {sup 11}Li. This result is a remarkable confluence of nuclear and atomic physics.

Benefits of a supportive development climate for older workers

Abstract: Purpose – This study aims to test a model of the relationships among older workers' propensity to engage in development activities (development orientation), their perceptions of the development opportunities associated with their job (job development climate), their commitment to their organization, and their intention to remain with their organization.Design/methodology/approach – Separate questionnaires were completed by 395 individuals aged 50 to 70, who were in their career job and 195 individuals aged 50 to 70 who were employed in a bridge job. Both questionnaires included measures of development orientation, job development climate, affective commitment and intention to remain as well as individual characteristics and organizational characteristics.Findings – The findings supported the proposed model in that development orientation was positively related to job development climate which, in turn, was positively related to affective commitment and affective commitment was positively related to inten...

Suprasubduction zone ophiolites and Archean tectonics

Abstract: The internal structure and geochemistry of many Phanerozoic ophiolites show a complex pattern of igneous accretion that involved multiple stages and sources of melt evolution and life cycles in suprasubduction zone (SSZ) environments ([Shervais, 2001][1]; [Dilek and Flower, 2003][2]). Some of the

Inter‐population variation in multiple paternity and reproductive skew in the guppy

Abstract: We use microsatellite loci to detail the multiple paternity patterns in broods from 10 wild populations of the guppy (Poecilia reticulata) found in Northern Trinidad. The populations span two major drainages comprising the Caroni and the Oropouche, and include sites that are characterized by either high or low predation. Across the populations the frequency of multiple paternity is high with 95% (range: 70%–100%) of broods having multiple sires. Broods have an average of 3.5 sires (range: 1–9) and a mixed-model analysis suggests that broods from high predation sites have marginally more sires than do those from low predation sites, but this is true only in the Oropouche drainage. There is no difference in sire number between predation sites in the Caroni drainage. Brood size, but not female body length, is correlated with the number of sires and the correlation cannot be attributed solely to the stochastic process associated with sperm competition and a ‘fair raffle’. Within broods there is significant skew in reproductive success among males, which may reflect variation in sperm competitiveness or female choice. There is, however, no difference in the skew among populations from different predation regimes or drainages. Finally, high predation populations were characterized by increased genetic variability at the microsatellite loci, suggesting a larger effective population size. We discuss explanations for the high degree of multiple paternity but the general lack of any major differences among broods from ecologically different populations.

Character amenability of Banach algebras

Abstract: We introduce the notion of character amenable Banach algebras. We prove that character amenability for either of the group algebra L1(G) or the Fourier algebra A(G) is equivalent to the amenability of the underlying group G. Character amenability of the measure algebra M(G) is shown to be equivalent to G being a discrete amenable group. We also study functorial properties of character amenability. For a commutative character amenable Banach algebra A, we prove all cohomological groups with coefficients in finite-dimensional Banach A-bimodules, vanish. As a corollary we conclude that all finite-dimensional extensions of commutative character amenable Banach algebras split strongly.

Personal digital assistants as cognitive aids for individuals with severe traumatic brain injury: A community-based trial

Abstract: Objective: The purpose of this study was to examine the efficacy of personal digital assistants (PDAs) as cognitive aids in a sample of individuals with severe traumatic brain injury (TBI).Method: ...

High precision atomic theory for Li and Be+: QED shifts and isotope shifts.

Abstract: High-precision results are presented for calculations of the nonrelativistic energies, relativistic corrections, and quantum electrodynamic corrections for the $2\text{ }^{2}S$, $2\text{ }^{2}P$, and $3\text{ }^{2}S$ states of Li and ${\mathrm{Be}}^{+}$, using nonrelativistic wave functions expressed in Hylleraas coordinates. Bethe logarithms are obtained for the states of ${\mathrm{Be}}^{+}$. Finite mass corrections are calculated with sufficient accuracy to extract the nuclear charge radius from measurements of the isotope shift for the $2\text{ }^{2}S\ensuremath{-}2\text{ }^{2}P$ and $2\text{ }^{2}S\ensuremath{-}3\text{ }^{2}S$ transitions. The calculated ionization potential for ${\mathrm{Be}}^{+}$ is $146\text{ }882.923\ifmmode\pm\else\textpm\fi{}0.005\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}1}$.

Recovery of corals a decade after a bleaching event in Dubai, United Arab Emirates

Abstract: Elevated sea surface temperatures in the late 1990s were associated with widespread coral mortality in the Arabian Gulf, particularly in Acropora dominated areas. This study investigates the composition, condition, and recruitment patterns of coral communities in Saih Al-Shaib, Dubai, United Arab Emirates, a decade after mass bleaching. Five statistically distinct communities were identified by cluster analysis, with grouping optimized from 17 significant indicator species. Overall, 25 species of scleractinian coral were observed, representing 35 ± 1.6% coral cover. Densities of recruits were low (0.8 ± 0.2 m−2), and composition generally reflected that of the surrounding adult community. Ten years after mass mortality, Acropora dominated assemblages were observed in three of the six sites examined and coral cover (41.9 ± 2.5%) was double post-bleaching cover. One shallow near-shore site appears to have had recovery of Acropora reset by a further bleaching event in 2002. However, the prevalence of young Acropora colonies here indicates that recovery may recur in several years. One area formerly dominated by Acropora is now dominated by faviids and poritids, with adult and juvenile composition suggesting this dominance shift is likely to persist. Porites lutea and Porites harrisoni dominated communities were negligibly impacted by the bleaching events, and the limited change in coral cover and composition in intervening years likely results from slow growth and low recruitment. Despite strong recovery of several dominant Acropora species, five formerly common species from this area were not observed suggesting local extinction. Dubai coral communities exhibit both resistance and resilience to elevated sea temperatures. The conservation of these patch reefs is warranted given the predicted increase in bleaching events, and the role that these communities may play in regional recovery.

Depression and Its Psychosocial Correlates Among Older Asian Immigrants in North America: A Critical Review of Two Decades' Research

Abstract: Objectives: This article critically reviews two decades of empirically based depression studies on older Asian immigrants (OAIs) in North America published in English. The Psychosocial Model of Late-Life Depression is proposed as the conceptual roadmap to help interpret the findings across studies. Methods: Using multiple bibliographic databases, this review systematically summarized and evaluated findings in 24 studies in terms of: (a) the prevalence and severity of depression; (b) demographic, psychosocial, cultural, and health risk factors of depression; and (c) methodological approaches and designs. Results: The results showed that depression is prevalent among OAIs and is linked to gender, recency of immigration, English proficiency, acculturation, service barriers, health status, relationship with children and family, and social support. However, considerable variability in the results, the sample sizes, and the use of measurements were also found across studies. Discussion: Recommendations for futu...