An efficient approach to understanding and predicting the effects of multiple task characteristics on performance

In ergonomics there is often a need to identify and predict the separate effects of multiple factors on performance. A cost-effective fractional factorial approach to understanding the relationship between task characteristics and task performance is presented. The method has been shown to provide sufficient independent variability to reveal and predict the effects of task characteristics on performance in two domains. The five steps outlined are: selection of performance measure, task characteristic identification, task design for user trials, data collection, regression model development and task characteristic analysis. The approach can be used for furthering knowledge of task performance, theoretical understanding, experimental control and prediction of task performance

Children's construction task performance and spatial ability: controlling task complexity and predicting mathematics performance.

This paper presents a methodology to control construction task complexity and examined the relationships between construction performance and spatial and mathematical abilities in children. The study included three groups of children (N = 96); ages 7-8, 10-11, and 13-14 years. Each group constructed seven pre-specified objects. The study replicated and extended previous findings that indicated that the extent of component symmetry and variety, and the number of components for each object and available for selection, significantly predicted construction task difficulty. Results showed that this methodology is a valid and reliable technique for assessing and predicting construction play task difficulty. Furthermore, construction play performance predicted mathematical attainment independently of spatial ability

A new model of how celebrity endorsements work: attitude toward the endorsement as a mediator of celebrity source and endorsement effects

This research introduces attitude towards the endorsement as a mediating variable in the relationships between celebrity source and endorsement factors and brand attitude. It also includes perceived celebrity motive, a variable rarely studied in the previous literature, as an endorsement factor. In a survey study, respondents evaluated four celebrity endorsement campaigns. Mediation analyses show that attitude towards the endorsement mediates the effects of three variables on brand attitude; these variables are celebrity expertise, celebrity–brand fit, and perceived celebrity motive. Moreover, results show that if consumers perceive that the celebrity was motivated to do the endorsement not only by money but also by product quality, this has a significant positive effect on attitude towards the brand

Testing and comparing two self-care-related instruments among older Chinese adults

Objectives The study aimed to test and compare the reliability and validity, including sensitivity and specificity of the two self-care-related instruments, the Self-care Ability Scale for the Elderly (SASE), and the Appraisal of Self-care Agency Scale-Revised (ASAS-R), among older adults in the Chinese context. Methods A cross-sectional design was used to conduct this study. The sample consisted of 1152 older adults. Data were collected by a questionnaire including the Chinese version of SASE (SASE-CHI), the Chinese version of ASAS-R (ASAS-R-CHI) and the Exercise of Self-Care Agency scale (ESCA). Homogeneity and stability, content, construct and concurrent validity, and sensitivity and specificity were assessed. Results The Cronbach's alpha (α) of SASE-CHI was 0.89, the item-to-total correlations ranged from r = 0.15 to r = 0.81, and the test-retest correlation coefficient (intra-class correlation coefficient, ICC) was 0.99 (95% CI, 0.99±1.00; P<0.001). The Cronbach's α of ASAS-R-CHI was 0.78, the item-to-total correlations ranged from r = 0.20 to r = 0.65, and the test-retest ICC was 0.95 (95% CI, 0.92±0.96; P<0.001). The content validity index (CVI) of SASE-CHI and ASAS-R-CHI was 0.96 and 0.97, respectively. The findings of exploratory and confirmatory factor analyses (EFA and CFA) confirmed a good construct validity of SASE-CHI and ASAS-R-CHI. The Pearson's rank correlation coefficients, as a measure of concurrent validity, between total score of SASE-CHI and ESCA and ASAS-R-CHI and ESCA were assessed to 0.65 (P<0.001) and 0.62 (P<0.001), respectively. Regarding ESCA as the criterion, the area under the receiver operator characteristic (ROC) curve for the cut-point of SASE-CHI and ASAS-R-CHI were 0.93 (95% CI, 0.91±0.94) and 0.83 (95% CI, 0.80±0.86), respectively. Conclusion There is no significant difference between the two instruments. Each has its own characteristics, but SASE-CHI is more suitable for older adults. The key point is that the users can choose the most appropriate scale according to the specific situation.publishedVersionNivå

Predicting management development and learning behaviour in New Zealand SMEs

Despite concern on the part of policy makers to raise managerial capability in SMEs, there is little evidence on the key drivers of owner-manager participation in management development programmes. The authors argue that such participation is poorly understood. The paper develops a predictive model of the drivers of participation in sources of learning by owner-managers. It tests a theoretical model, based on the small firm as a learning organization, which posits that participation is driven by owner-managers\u27 learning orientation and the extent of their belief in self-improvement. The implications of the results are discussed in light of the provision of management development programmes. <br /

Simpson's Paradox, Lord's Paradox, and Suppression Effects are the same phenomenon – the reversal paradox

This article discusses three statistical paradoxes that pervade epidemiological research: Simpson's paradox, Lord's paradox, and suppression. These paradoxes have important implications for the interpretation of evidence from observational studies. This article uses hypothetical scenarios to illustrate how the three paradoxes are different manifestations of one phenomenon – the reversal paradox – depending on whether the outcome and explanatory variables are categorical, continuous or a combination of both; this renders the issues and remedies for any one to be similar for all three. Although the three statistical paradoxes occur in different types of variables, they share the same characteristic: the association between two variables can be reversed, diminished, or enhanced when another variable is statistically controlled for. Understanding the concepts and theory behind these paradoxes provides insights into some controversial or contradictory research findings. These paradoxes show that prior knowledge and underlying causal theory play an important role in the statistical modelling of epidemiological data, where incorrect use of statistical models might produce consistent, replicable, yet erroneous results

Who Believes in the Giant Skeleton Myth? An Examination of Individual Difference Correlates

This study examined individual difference correlates of belief in a narrative about the discovery of giant skeletal remains that contravenes mainstream scientific explanations. A total of 364 participants from Central Europe completed a survey that asked them to rate their agreement with a short excerpt describing the giant skeleton myth. Participants also completed measures of the Big Five personality factors, New Age orientation, anti-scientific attitudes, superstitious beliefs, and religiosity. Results showed that women, as compared with men, and respondents with lower educational qualifications were significantly more likely to believe in the giant skeleton myth, although effect sizes were small. Correlational analysis showed that stronger belief in the giant skeleton myth was significantly associated with greater anti-scientific attitudes, stronger New Age orientation, greater religiosity, stronger superstitious beliefs, lower Openness to Experience scores, and higher Neuroticism scores. However, a multiple regression showed that the only significant predictors of belief in myth were Openness, New Age orientation, and anti-scientific attitudes. These results are discussed in relation to the potential negative consequences of belief in myths

Occupational stress in health professionals: a study with Portuguese Nurses

Este trabalho analisa o estresse ocupacional em 286 enfermeiros de hospitais e centros de saúde portugueses. Avaliaram-se as fontes de estresse, o burnout, os problemas de saúde física, a satisfação e a realização profissional. Os resultados apontaram 30% de enfermeiros com experiências significativas de estresse e 15% com problemas de exaustão emocional. As análises de regressão múltipla apontaram maior capacidade preditiva das dimensões de estresse na exaustão emocional, na saúde física, na satisfação e na realização profissional. As análises comparativas evidenciaram maiores problemas de stresse e reacções mais negativas ao trabalho nas mulheres, nos enfermeiros mais novos e com menor experiência, nos trabalhadores com contratos a prazo, nos profissionais que realizam trabalho por turnos e nos que trabalham mais horas.This work analyses occupational stress in 286 nurses from hospitals and health care centres in Portugal. The following dimensions were evaluated: stress, burnout, physical health problems, satisfaction and professional fulfilment. Results revealed significant stress experiences in 30% of the professionals, and emotional exhaustion problems in 15%. Multiple regression analysis pointed out stress as an important predictor of emotional exhaustion, physical health, satisfaction and professional fulfilment. Comparative analysis suggested more occupational stress and professional negative experiences in the following groups: female nurses, younger and less experienced nurses, those with short-term working contracts, nurses working on a shift-basis system, and nurses working during long hours.(undefined

Mathematical Modeling of a Bioluminescent E. Coli Based Biosensor

In this work we present a mathematical model for the bioreporter activity of&nbsp;an E. coli based bioluminescent bioreporter. This bioreporter is based on a genetically&nbsp;modified E. coli which harbors the recA promoter, a member of the bacterial SOS&nbsp;response, fused to the bacterial luminescence (lux) genes. This bioreporter responds&nbsp;to the presence of DNA damaging agents such as heavy metals, H2O2 and Nalidixic&nbsp;Acid (NA) that activate the SOS response. In our mathematical model we implemented&nbsp;basic physiological mechanisms such as: the penetration of the NA into the biosensor;&nbsp;gyrase enzyme inhibition by the NA; gyrase level regulation; creation of chromosomal&nbsp;DNA damage; DNA repair and release of ssDNA into the cytoplasm; SOS induction and&nbsp;chromosomal DNA repair; activation of lux genes by the fused recA promoter carried on&nbsp;a plasmidal DNA; transcription and translation of the luminescence responsible enzymes;&nbsp;luminescence cycle; energy molecules level regulation and the regulation of the O2&nbsp;consumption. The mathematical model was defined using a set of ordinary differential&nbsp;equations (ODE) and solved numerically. We simulated the system for different concentrations of NA in water for specific biosensors concentration, and under limited O2&nbsp;conditions. The simulated results were compared to experimental data and satisfactory&nbsp;matching was obtained. This manuscript presents a proof of concept showing that&nbsp;real biosensors can be modeled and simulated. This sets the ground to the next stage&nbsp;of implementing a comprehensive physiological model using experimentally extracted&nbsp;parameters. Following the completion of the next stage, it will be possible to construct&nbsp;a “Computer Aided Design” tool for the simulation of the genetically engineered&nbsp;biosensors. We define a term “bioCAD” for a Biological System Computer Aided Design.&nbsp;The specific bioCAD that is described here is aimed towards whole cell biosensors which&nbsp;are under investigation today for functional sensing. Usage of the bioCAD will improve&nbsp;the biosensors design process and boost their performance. It will also reduce Non&nbsp;Recurring Engineering (NRE) cost and time. Finally, using a parameterized solution&nbsp;will allow fair and quick evaluation of whole cell biosensors for various applications

An examination of the factorial and convergent validity of four measures of conspiracist ideation, with recommendations for researchers

A number scales have been developed to measure conspiracist ideation, but little attention has been paid to the factorial validity of these scales. We reassessed the psychometric properties of four widely-used scales, namely the Belief in Conspiracy Theories Inventory (BCTI), the Conspiracy Mentality Questionnaire (CMQ), the Generic Conspiracist Beliefs Scale (GCBS), and the One-Item Conspiracy Measure (OICM). Eight-hundred-and-three U. S. adults completed all measures, along with measures of endorsement of 9/11 and anti- vaccination conspiracy theories. Through both exploratory and confirmatory factor analysis, we found that only the BCTI had acceptable factorial validity. We failed to confirm the factor structures of the CMQ and the GBCS, suggesting these measures had poor factorial valid- ity. Indices of convergent validity were acceptable for the BCTI, but weaker for the other measures. Based on these findings, we provide suggestions for the future refinement in the measurement of conspiracist ideation