Showing papers by "Andrew J. Martin published in 2011"

Academic self‐concept and academic achievement: Relations and causal ordering

Abstract: Background. A positive self-concept is valued as a desirable outcome in many disciplines of psychology as well as an important mediator to other outcomes. Aims. The present review examines support for the reciprocal effects model (REM) that posits academic self-concept (ASC) and achievement are mutually reinforcing, each leading to gains in the other – and its extension to other achievement domains. Method. We review theoretical, methodological, and empirical support for the REM. Critical features in this research are a theoretical emphasis on multidimensional perspectives that focus on specific components of self-concept and a methodological focus on a construct validity approach to evaluating the REM. Results. Consistent with these distinctions, REM research and a comprehensive meta-analysis show that prior ASC has direct and indirect effects on subsequent achievement, whilst the effects of self-esteem and other non-academic components of self-concept are negligible. We then provide an overview of subsequent support for the generality of the REM for: young children, cross-cultural, health (physical activity), and non-elite (gymnastics) and elite (international swimming championships) sport. Conclusion. This research is important in demonstrating that increases in ASC lead to increases in subsequent academic achievement and other desirable educational outcomes. Findings confirm that not only is self-concept an important outcome variable in itself, it also plays a central role in affecting other desirable educational outcomes. Implications for educational practice are discussed.

Bacterial virulence in the moonlight: multitasking bacterial moonlighting proteins are virulence determinants in infectious disease.

Abstract: Men may not be able to multitask, but it is emerging that proteins can. This capacity of proteins to exhibit more than one function is termed protein moonlighting, and, surprisingly, many highly conserved proteins involved in metabolic regulation or the cell stress response have a range of additional biological actions which are involved in bacterial virulence. This review highlights the multiple roles exhibited by a range of bacterial proteins, such as glycolytic and other metabolic enzymes and molecular chaperones, and the role that such moonlighting activity plays in the virulence characteristics of a number of important human pathogens, including Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, Helicobacter pylori, and Mycobacterium tuberculosis.

Association between human rhinovirus C and severity of acute asthma in children

Abstract: A new and potentially more pathogenic group of human rhinovirus (HRV), group C (HRVC), has recently been discovered. We hypothesised that HRVC would be present in children with acute asthma and cause more severe attacks than other viruses or HRV groups. Children with acute asthma (n = 128; age 2-16 yrs) were recruited on presentation to an emergency department. Asthma exacerbation severity was assessed, and respiratory viruses and HRV strains were identified in a nasal aspirate. The majority of the children studied had moderate-to-severe asthma (85.2%) and 98.9% were admitted to hospital. HRV was detected in 87.5% and other respiratory viruses in 14.8% of children, most of whom also had HRV. HRVC was present in the majority of children with acute asthma (59.4%) and associated with more severe asthma. Children with HRVC (n = 76) had higher asthma severity scores than children whose HRV infection was HRVA or HRVB only (n = 34; p = 0.018), and all other children (n = 50; p = 0.016). Of the 19 children with a non-HRV virus, 13 had HRV co-infections, seven of these being HRVC. HRVC accounts for the majority of asthma attacks in children presenting to hospital and causes more severe attacks than previously known HRV groups and other viruses.

Methodological Measurement Fruitfulness of Exploratory Structural Equation Modeling (ESEM): New Approaches to Key Substantive Issues in Motivation and Engagement.

Abstract: The most popular measures of multidimensional constructs typically fail to meet standards of good measurement: goodness of fit, measurement invariance, lack of differential item functioning, and well-differentiated factors that are not so highly correlated as to detract from their discriminant validity. Part of the problem, the authors argue, is undue reliance on overly restrictive independent cluster models of confirmatory factor analysis (ICM-CFA) in which each item loads on one, and only one, factor. Here the authors demonstrate exploratory structural equation modeling (ESEM), an integration of the best aspects of CFA and traditional exploratory factor analyses (EFA). On the basis of responses to the 11-factor Motivation and Engagement Scale (n = 7,420, Mage = 14.22), we demonstrate that ESEM fits the data much better and results in substantially more differentiated (less correlated) factors than corresponding CFA models. Guided by a 13-model taxonomy of ESEM full-measurement (mean structure) invarianc...

Bacterial moonlighting proteins and bacterial virulence.

Abstract: Implicit in the central dogma is the hypothesis that each protein gene product has but one function. However, over the past decade, it has become clear that many proteins have one or more unique functions, over-and-above the principal biological action of the specific protein. This phenomenon is now known as protein moonlighting and many well-known proteins such as metabolic enzymes and molecular chaperones are now recognised as moonlighting proteins. A growing number of bacterial species are being found to have moonlighting proteins and the moonlighting activities of such proteins can contribute to bacterial virulence behaviour. The glycolytic enzymes, glyceraldehyde-3-phosphate dehydrogenase (GAPD) and enolase, and the cell stress proteins: chaperonin 60, Hsp70 and peptidyl prolyl isomerase, are among the most common of the bacterial moonlighting proteins which play a role in bacterial virulence. Moonlighting activities include adhesion and modulation of cell signalling processes. It is likely that only the tip of the bacterial moonlighting iceberg has been sighted and the next decade will bring with it many new discoveries of bacterial moonlighting proteins with a role in bacterial virulence.

Peer relationships and adolescents' academic and non-academic outcomes: same-sex and opposite-sex peer effects and the mediating role of school engagement

Abstract: Background. The literature has documented theoretical/conceptual models delineating the facilitating role of peer relationships in academic and non-academic outcomes. However, the mechanisms through which peer relationships link to those outcomes is an area requiring further research. Aims. The study examined the role of adolescents’ perceptions of their relationships with same-sex and opposite-sex peers in predicting their academic performance and general self-esteem and the potentially mediating role of school engagement in linking these perceived peer relationships with academic and non-academic outcomes. Sample. The sample comprised 1,436 high-school students (670 boys, 756 girls; 711 early adolescents, 723 later adolescents). Method. Self-report measures and objective achievement tests were used. Structural equation modelling (SEM) was performed to test the hypothesized model and its invariance across gender and age groups. Results. Perceived same-sex peer relationships yielded positive direct and indirect links with academic performance and general self-esteem. Perceived opposite-sex peer relationships yielded positive direct and indirect links with general self-esteem and an indirect positive link with academic performance, but mediation via school engagement was not as strong as that of perceived same-sex peer relationships. These findings generalized across gender and age groups. Conclusion. Adolescents’ same-sex and opposite-sex peer relationships seem to positively impact their academic performance and general self-esteem in distinct ways. It appears that school engagement plays an important role in mediating these peer relationship effects, particularly those of same-sex peer relationships, on academic and non-academic functioning. Implications for psycho-educational theory, measurement, and practice are discussed.

Safety and efficacy of pregabalin in patients with central post-stroke pain.

Abstract: Pregabalin has demonstrated efficacy in several forms of neuropathic pain, but its long-term efficacy in central post-stroke pain (CPSP) is unproven. We evaluated the efficacy and safety of pregabalin versus placebo in patients with CPSP. A 13-week, randomized, double-blind, multicenter, pla

Holding back and holding behind: Grade retention and students’ non-academic and academic outcomes

Abstract: The present study examined the implications of grade retention (repeating a grade) and social promotion (automatic promotion to the next grade each year) for high school students’ academic and non-academic outcomes. Based on data from 3261 high school students, structural equation modeling demonstrated that, after controlling for interactions with other factors, demographic covariates and ability, there were significant (p < 0.001) main effects of grade retention. In terms of academic factors, grade retention was a significant negative predictor of academic self-concept and homework completion and a significant positive predictor of maladaptive motivation and weeks absent from school. In terms of non-academic factors, grade retention was a significant negative predictor of self-esteem but was not significantly associated with relationship with peers. In follow-up analyses using a sub-sample of retained (n = 186) and promoted (n = 186) students matched by ability, age and gender, findings were confirmed an...

Bacterial causes of empyema in children, Australia, 2007-2009

Abstract: An increase in the incidence of empyema worldwide could be related to invasive pneumococcal disease caused by emergent nonvaccine replacement serotypes. To determine bacterial pathogens and pneumococcal serotypes that cause empyema in children in Australia, we conducted a 2-year study of 174 children with empyema. Blood and pleural fluid samples were cultured, and pleural fluid was tested by PCR. Thirty-two (21.0%) of 152 blood and 53 (33.1%) of 160 pleural fluid cultures were positive for bacteria; Streptococcus pneumoniae was the most common organism identified. PCR identified S. pneumoniae in 74 (51.7%) and other bacteria in 19 (13.1%) of 145 pleural fluid specimens. Of 53 samples in which S. pneumoniae serotypes were identified, 2 (3.8%) had vaccine-related serotypes and 51 (96.2%) had nonvaccine serotypes; 19A (n = 20; 36.4%), 3 (n = 18; 32.7%), and 1 (n = 8; 14.5%) were the most common. High proportions of nonvaccine serotypes suggest the need to broaden vaccine coverage.

Clergy motivation and occupational well-being: exploring a quadripolar model and its role in predicting burnout and engagement.

Abstract: Clergy represent a salient group in Western communities, providing a variety of services aimed at supporting diverse members of those communities. Significantly, rates of attrition among clergy are high, suggesting the need to better understand their occupational well-being and factors relevant to it. The present study draws on the quadripolar need achievement framework to hypothesize motivational profiles among clergy and the extent to which these profiles predict occupational well-being, as indicated by low burnout and high engagement. K-means cluster analysis with 200 clergy confirmed a quadripolar motivational profile (success-oriented, overstriving, self-protecting, failure accepting). Using these group profiles as predictors, structural equation modeling identified significant effects on all burnout and engagement factors, with success-oriented, overstriving, self-protecting, and failure accepting groups each reflecting differential occupational well-being profiles. Substantive and applied implications of these findings are discussed.

Use of student ratings to benchmark universities: Multilevel modeling of responses to the Australian Course Experience Questionnaire (CEQ)

Abstract: Recently graduated university students from all Australian Universities rate their overall departmental and university experiences (DUEs), and their responses (N = 44,932, 41 institutions) are used by the government to benchmark departments and universities. We evaluate this DUE strategy of rating overall departments and universities rather than individual teachers, and we juxtapose it with the traditional use of student ratings to evaluate individual teachers (SETs). Multilevel analyses of DUE overall ratings were not able to discriminate well between universities or departments--few universities or departments differed significantly from the grand mean. Although the a priori 5-factor structure for this DUE instrument was reasonably well-defined at the individual student level, none of the 5 factors separately or in combination discriminated well between departments or universities. In contrast to this pattern of results, we review studies showing that SETs do reliably differentiate between teachers and are valid in relation to many criteria of effective teaching. However, casual reviews of these research literatures should not use this support for SETs to justify the use of DUE-type strategies. We conclude that DUE-type ratings should be used with great caution, if at all, and should not be seen as an alternative to SETs

Patterns of Multilevel Variance in Psycho-Educational Phenomena: Comparing Motivation, Engagement, Climate, Teaching, and Achievement Factors 1Dieser Beitrag wurde unter der geschäftsführenden Herausgeberschaft von Jens Möller angenommen.

Abstract: . The present study explored multilevel variance for a range of salient psycho-educational factors in mathematics. With a sample of 4,383 students (Years 5–8) in 257 classrooms and 47 schools, data indicated patterns of variance across the selection of psycho-educational factors. For all factors, the bulk of variance resided at the student (and residual) level. In ascending order of upper-level variance were motivation, perceived motivational ‘climate’, homework completion, teacher-student relationships, and achievement – with motivation and perceived ‘climate’ yielding very little upper-level variance. Hence, although there is usually a hierarchical structure in which psycho-educational factors are situated, there is variation in patterns of multilevel variance across the range of factors. In exploring a range of psycho-educational phenomena from a multilevel perspective, the present study offers further direction for researchers selecting and operationalizing psycho-educational phenomena in mult...

The effect of prolonged darkness on the growth, recovery and survival of Antarctic sea ice diatoms

Abstract: While global climate change in polar regions is expected to cause significant warming, the annual cycle of light and dark will remain unchanged. Cultures of three species of Antarctic sea ice diatoms, Fragilariopsis cylindrus (Grunow) Krieger, Thalassiosira antarctica Comber and Entomoneis kjellmanii (P.T. Cleve) Poulin and Cardinal, were incubated in the dark and exposed to differing temperatures. Maximum dark survival times varied between 30 and 60 days. Photosynthetic parameters, photosynthetic efficiency (α), maximum quantum yield (Fv/Fm), maximum relative electron transport rate (rETRmax) and non-photochemical quenching (NPQ), showed that dark exposure had a significant impact on photoacclimation. In contrast, elevated temperatures had a relatively minor impact on photosynthetic functioning during the dark exposure period but had a considerable impact on dark survival with minimal dark survival times reduced to only 7 days when exposed to 10°C. Recovery of maximum quantum yield of fluorescence (Fv/Fm) was not significantly impacted by temperature, species or dark exposure length. Recovery rates of Fv/Fm ranged from −5.06E−7 ± 2.71E−7 s−1 to 1.36E−5 ± 1.53E−5 s−1 for monthly experiments and from −9.63E−7 ± 7.71E−7 s−1 to 2.65E−5 ± 2.97E−5 s−1 for weekly experiments. NPQ recovery was greater and more consistent than Fv/Fm recovery, ranging between 5.74E−7 ± 8.11E−7 s−1 to 7.50E−3 ± 7.1E−4 s−1. The concentration of chl-a and monosaccharides remained relatively constant in both experiments. These results suggest that there will probably be little effect on Antarctic microalgae with increasing water temperatures during the Antarctic winter.

Prescriptive Statements and Educational Practice: What Can Structural Equation Modeling (SEM) Offer?.

Abstract: Longitudinal structural equation modeling (SEM) can be a basis for making prescriptive statements on educational practice and offers yields over “traditional” statistical techniques under the general linear model. The extent to which prescriptive statements can be made will rely on the appropriate accommodation of key elements of research design, measurement, and theory. If these key elements are not adequately incorporated in educational SEM research, prescriptive statements become less justified, and in many cases, untenable. This is not to discount cross-sectional SEM as a basis for prescriptive considerations; however, it is more defensible to consider cross-sectional findings in terms of prescriptive possibilities and prescriptive inferences rather than prescriptive statements. This article examines what, when, and how SEM can contribute to prescriptive statements in education.

Content and Structure of Values in Middle Adolescence: Evidence From Singapore, the Philippines, Indonesia, and Australia

Abstract: Schwartz’s theory of the content and structure of human values has been validated mostly with adult (teacher and university student) samples. The present study examines the content and structure of values of middle adolescents in Singapore, the Philippines, Indonesia, and Australia. The 40-item version of the Portrait Values Questionnaire was administered to 230 adolescents in each country (total N = 920; boys and girls were equal) and smallest space analysis was performed. Consistent with theory, the 10 first-order values and the four second-order values, organized in two bipolar dimensions, were identified in all samples. In support of the developmentally modified value model for young people, there was some evidence for the periphery of power to achievement. Interestingly, the location of benevolence and universalism were reversed across all cultural groups, and tradition values separated into self-restriction and faith. Overall, the findings support the claim that Schwartz’s theory of values is neithe...

Grammars leak: Modeling how phonotactic generalizations interact within the grammar

Abstract: I present evidence from Navajo and English that weaker, gradient versions of morpheme-internal phonotactic constraints, such as the ban on geminate consonants in English, hold even across prosodic word boundaries. I argue that these lexical biases are the result of a maximum entropy phonotactic learning algorithm that maximizes the probability of the learning data, but that also contains a smoothing term that penalizes complex grammars. When this learner attempts to construct a grammar in which some constraints are blind to morphological structure, it underpredicts the frequency of compounds that violate a morpheme-internal phonotactic. I further show how, over time, this learning bias could plausibly lead to the lexical biases seen in Navajo and English.

Risk, protection, and resilience in Chinese adolescents: A psycho-social study: Resilience and Chinese youth

Abstract: A total of 636 Grade 11 Chinese students completed measures of risk factors, protective factors, and problem behaviour complemented by achievement data. In terms of risk factors, poor parental management and low school commitment were significant predictors of problem behaviour while low school commitment was a significant predictor of low academic achievement. In terms of protective factors, family attachment, opportunities and recognition for pro-social involvement in school, and high school expectation of behaviour negatively predict problem behaviour. Pro-social involvement in school and high expectations of behaviour significantly predict academic achievement. There was also a significant difference on protective factors between resilient and non-resilient groups from high-risk family environments.

Response of sea-ice microbial communities to environmental disturbance: an in situ transplant experiment in the Antarctic

Abstract: Sea-ice microbial communities are integral to primary and secondary production in icecovered regions of the Southern Ocean, but few studies have characterised the heterogeneity of microbes within the ice or determined whether habitat variability influences community dynamics. We examined the response of sea-ice microbes to key physicochemical variables by conducting an 18 d reciprocal transplant experiment within Antarctic fast-ice. A series of ice cores were extracted from 2.6 m annual ice and reinserted upside down to expose resident microbial assemblages to significantly different light, temperature and salinity regimes. The abundance and community composition of bacteria, microalgae and protozoa was subsequently determined within 3 sections of each core (top, middle and bottom) and compared with experimental controls. Results demonstrate that iceassociated microbes are finely attuned to discrete microhabitats within the sea-ice matrix. Positive growth and a shift in community composition was observed for microalgae moved from the top to the bottom of the ice, but significant bleaching of photosynthetic pigments resulted in zero net growth for bottom-ice communities exposed to the surface. Although bacteria may have been less vulnerable to initial change in their microenvironment, there was no significant increase in the average abundance of cells at either end of the flipped cores after 18 d, despite a presumed increase in algal-derived dissolved organic matter. This suggests a significant lag in the response time of bacteria to available growth substrates and a temporary ‘malfunction’ of the microbial loop.

Characterization of pathogenic germline mutations in human Protein Kinases

Abstract: Background: Protein Kinases are a superfamily of proteins involved in crucial cellular processes such as cell cycle regulation and signal transduction. Accordingly, they play an important role in cancer biology. To contribute to the study of the relation between kinases and disease we compared pathogenic mutations to neutral mutations as an extension to our previous analysis of cancer somatic mutations. First, we analyzed native and mutant proteins in terms of amino acid composition. Secondly, mutations were characterized according to their potential structural effects and finally, we assessed the location of the different classes of polymorphisms with respect to kinaserelevant positions in terms of subfamily specificity, conservation, accessibility and functional sites. Results: Pathogenic Protein Kinase mutations perturb essential aspects of protein function, including disruption of substrate binding and/or effector recognition at family-specific positions. Interestingly these mutations in Protein Kinases display a tendency to avoid structurally relevant positions, what represents a significant difference with respect to the average distribution of pathogenic mutations in other protein families. Conclusions: Disease-associated mutations display sound differences with respect to neutral mutations: several amino acids are specific of each mutation type, different structural properties characterize each class and the distribution of pathogenic mutations within the consensus structure of the Protein Kinase domain is substantially different to that for non-pathogenic mutations. This preferential distribution confirms previous observations about the functional and structural distribution of the controversial cancer driver and passenger somatic mutations and their use as a proxy for the study of the involvement of somatic mutations in cancer development.

RepCloud: achieving fine-grained cloud TCB attestation with reputation systems

Abstract: Security concerns for emerging cloud computing models have become the focus of much research, but little of this targets the underlying infrastructure. Trusted Cloud proposals generally assert that the Trusted Computing Base (TCB) of the cloud should be clearly defined and attested to. However, specific characteristics of trust in the cloud make such solutions difficult to implement in an effective and practical way. We present RepCloud, a reputation system for managing decentralised attestation metrics in the cloud. We observe that as being deterministic and tamper-proof, trust evidence generated by the TCG framework can be efficiently transmitted within the cloud. In a web of nodes with high connectivity and mutual-attestation frequency, corrupted nodes can be identified effectively. By modelling this web with RepCloud, we achieved a fine-grained cloud TCB attestation scheme with high confidence for trust. Cloud users can determine the security properties of the exact nodes that may affect the genuine functionalities of their applications, without obtaining much internal information of the cloud. Experiments showed that besides achieved fine-grained attestation RepCloud still incurred lower trust management overhead than existing trusted cloud proposals.

Osteoporosis in men: a review of endogenous sex hormones and testosterone replacement therapy

Abstract: The prevalence of osteoporosis is estimated to be 18% in men, but 30% of all fractures occur in men. With age, men experience a gradual decline in testosterone production and bone density. The rate of trabecular bone loss in the lumbar spine in men over age 50 can be double the rate of loss in men under age 50. Endogenous testosterone, estradiol, and their metabolites play a role in maintaining bone health, but their specific effects on bone turnover have been difficult to elucidate. Recently, large cohort studies have provided more detailed information confirming estrogen's associations and further characterizing the effect of endogenous testosterone and its metabolites on bone mineral density and fractures. Very few clinical trials have assessed the impact of testosterone replacement therapy (TRT) on bone density and fractures in men. The few studies that have been conducted are generally small and not robust enough to show the true treatment effect of TRT and adequately determine its safety. In the absence of data on patient outcomes, it is important for pharmacists to understand the impact of drug therapy on biomarkers and surrogate markers of disease for optimal pharmacotherapy selection and monitoring.

Osteoporosis in Men

Abstract: The prevalence of osteoporosis is estimated to be 18% in men, but 30% of all fractures occur in men. With age, men experience a gradual decline in testosterone production and bone density. The rate of trabecular bone loss in the lumbar spine in men over age 50 can be double the rate of loss in men under age 50. Endogenous testosterone, estradiol, and their metabolites play a role in maintaining bone health, but their specific effects on bone turnover have been difficult to elucidate. Recently, large cohort studies have provided more detailed information confirming estrogen’s associations and further characterizing the effect of endogenous testosterone and its metabolites on bone mineral density and fractures. Very few clinical trials have assessed the impact of testosterone replacement therapy (TRT) on bone density and fractures in men. The few studies that have been conducted are generally small and not robust enough to show the true treatment effect of TRT and adequately determine its safety. In the abs...

A bedside assay to detect streptococcus pneumoniae in children with empyema

Abstract: Background Empyema is a complication of pneumonia, commonly caused by Streptococcus pneumoniae. Aims To validate the utility of an immunochromatographic test for the detection of S. pneumoniae antigen in the pleural fluid of children with empyema. Methods Empyema patients had blood and pleural fluid cultured, and polymerase chain reaction (PCR) to detect the S. pneumoniae autolysin gene, lytA, in pleural fluid. Pleural fluid was tested using the Binax NOW S. pneumoniae antigen detection assay and compared with lytA PCR results and/or culture in blood or pleural fluid. Results S. pneumoniae was detected by PCR in pleural fluid of 68 of 137 (49.6%) patients, by culture in 11 of 135 (8.1%) pleural specimens and 16 of 120 (13.3%) blood specimens. Pleural fluid Binax NOW testing from 130 patients demonstrated a sensitivity of 83.8% and specificity of 93.5% (positive predictive value of 93.4% and negative predictive value of 84.1%). Conclusions In pediatric empyema, high predictive values of pleural fluid Binax NOW S. pneumoniae antigen test suggest that this test may help rationalize antibiotic choice in these patients. Pediatr Pulmonol. 2011; 46:179-183. (C) 2011 Wiley-Liss, Inc.