Psychosocial sources of stress and burnout in the consruction sector : a structural equation model. 'Fuentes psicosociales de estr??s y burnout en el sector de la construcci??n : un modelo de ecuaciones estructurales'

Resumen tomado de la publicaci??n. Resumen tambi??n en ingl??s

Transfer of knowledge of the structural components of the model Q400 and Global Express: the case of Aerospace Bombardier, Querétaro

The aim of this paper is to analyze the knowledge transfer in the production of structural components of two aircraft:Q400 and Global Express of Bombardier Aerospace Company, Querétaro. Bombardier Aerospace is a pioneer company in the aviation sector in Mexico, and the third largest civil aircraft manufacturer. In 2005, Bombardier decided to invest in Mexico, creating Bombardier Aerospace de Mexico S. A. C. V. and transferring production lines from Japan and Toronto to Queretaro. The relocation strategy of both plants aims to reduce modular and general production costs facing other competitors. The relocation has been supported by the State Government funds, through a trust and the creation of Queretaro aerospace cluster. Among various benefits, the State of Queretaro donated seventy-eight acres of land where the Queretaro International Airport (QIA) and a training centre will be built to promote the development of this sector. The interest in this research is to analyze and describe the transfer of knowledge to the production of structural components of both aircraft models, thanks to the results of productivity and internal and external factors which have contributed along with this transfer

Rapid model quality assessment for protein structure predictions using the comparison of multiple models without structural alignments

MOTIVATION: The accurate prediction of the quality of 3D models is a key component of successful protein tertiary structure prediction methods. Currently, clustering or consensus based Model Quality Assessment Programs (MQAPs) are the most accurate methods for predicting 3D model quality; however they are often CPU intensive as they carry out multiple structural alignments in order to compare numerous models. In this study, we describe ModFOLDclustQ - a novel MQAP that compares 3D models of proteins without the need for CPU intensive structural alignments by utilising the Q measure for model comparisons. The ModFOLDclustQ method is benchmarked against the top established methods in terms of both accuracy and speed. In addition, the ModFOLDclustQ scores are combined with those from our older ModFOLDclust method to form a new method, ModFOLDclust2, that aims to provide increased prediction accuracy with negligible computational overhead. RESULTS: The ModFOLDclustQ method is competitive with leading clustering based MQAPs for the prediction of global model quality, yet it is up to 150 times faster than the previous version of the ModFOLDclust method at comparing models of small proteins (<60 residues) and over 5 times faster at comparing models of large proteins (>800 residues). Furthermore, a significant improvement in accuracy can be gained over the previous clustering based MQAPs by combining the scores from ModFOLDclustQ and ModFOLDclust to form the new ModFOLDclust2 method, with little impact on the overall time taken for each prediction. AVAILABILITY: The ModFOLDclustQ and ModFOLDclust2 methods are available to download from: http://www.reading.ac.uk/bioinf/downloads/ CONTACT: l.j.mcguffin@reading.ac.uk.

Simple general method of generating non-oxo, non-amavadine model octacoordinated vanadium(IV) complexes of some tetradentate ONNO chelating ligands from various oxovanadium(IV/V) compounds and structural characterization of one of them

A simple general route of obtaining very stable octacoordinated non-oxovanadium( IV) complexes of the general formula VL2 (where H2L is a tetradentate ONNO donor) is presented. Six such complexes (1-6) are adequately characterized by elemental analysis, mass spectrometry, and various spectroscopic techniques. One of these compounds (1) has been structurally characterized. The molecule has crystallographic 4 symmetry and has a dodecahedral structure existing in a tetragonal space group P4n2. The non-oxo character and VL2 stoichiometry for all of the complexes are established from analytical and mass spectrometric data. In addition, the non-oxo character is clearly indicated by the complete absence of the strong nu(v=o) band in the 925-1025 cm(-1) region, which is a signature of all oxovanadium species. The complexes are quite stable in open air in the solid state and in solution, a phenomenon rarely observed in non-oxovanadium(IV) or bare vanadium(IV) complexes.

Bayesian model averaging and identification of structural breaks in time series

Bayesian Model Averaging (BMA) is used for testing for multiple break points in univariate series using conjugate normal-gamma priors. This approach can test for the number of structural breaks and produce posterior probabilities for a break at each point in time. Results are averaged over specifications including: stationary; stationary around trend and unit root models, each containing different types and number of breaks and different lag lengths. The procedures are used to test for structural breaks on 14 annual macroeconomic series and 11 natural resource price series. The results indicate that there are structural breaks in all of the natural resource series and most of the macroeconomic series. Many of the series had multiple breaks. Our findings regarding the existence of unit roots, having allowed for structural breaks in the data, are largely consistent with previous work.

Hypotheses testing for structural calibration model

The main objective of this paper is to discuss maximum likelihood inference for the comparative structural calibration model (Barnett, in Biometrics 25:129-142, 1969), which is frequently used in the problem of assessing the relative calibrations and relative accuracies of a set of p instruments, each designed to measure the same characteristic on a common group of n experimental units. We consider asymptotic tests to answer the outlined questions. The methodology is applied to a real data set and a small simulation study is presented.

Customer repurchase intention: a general structural equation model

This paper develops a general service sector model of repurchase intention from the consumer theory literature. A key contribution of the structural equation model is the incorporation of customer perceptions of equity and value and customer brand preference into an integrated repurchase intention analysis. The model describes the extent to which customer repurchase intention is influenced by seven important factors – service quality, equity and value, customer satisfaction, past loyalty, expected switching cost and brand preference. The general model is applied to customers of comprehensive car insurance and personal superannuation services. The analysis finds that although perceived quality does not directly affect customer satisfaction, it does so indirectly via customer equity and value perceptions. The study also finds that past purchase loyalty is not directly related to customer satisfaction or current brand preference and that brand preference is an intervening factor between customer satisfaction and repurchase intention. The main factor influencing brand preference was perceived value with customer satisfaction and expected switching cost having less influence.

Corporate codes of ethics in Australia, Canada and USA : measurement and structural properties of a cross-cultural model

The objective is to test the consistency of measurement and structural properties in a model of corporate codes of ethics (CCE) on an aggregated level and across multiple samples derived from three countries, namely Australia, Canada and the USA. The properties of four constructs of CCE are described and tested, these being: surveillance/training, internal communication, external communication, and guidance. The conclusion is that the measurement and structural models on an aggregated level have a satisfactory fit, validity and reliability. Furthermore, they are consistent when tested on each of the three samples (i.e. cross-validated). The cross-cultural model makes a contribution in addition to previous mostly descriptive studies and theory in the field using confirmatory factor analysis and structural equation modeling.

Towards an understanding of knowledge sharing behavior of CCOs in Bangladesh : a proposed structural equations model

This paper explores the question or whether Call Center Operators (CCO) share information or knowledge with their clients and if their knowledge sharing behavior has any impact on the sustainability of their relationships with their clients.

The structural properties of sexual fantasies for sexual offenders : a preliminary model

While the phenomenon of sexual fantasy has been researched extensively, little contemporary inquiry has investigated the structural properties of sexual fantasy within the context of sexual offending. In this study, a qualitative analysis was used to develop a descriptive model of the phenomena of sexual fantasy during the offence process. Twenty-four adult males convicted of sexual offences provided detailed retrospective descriptions of their thoughts, emotions and behaviours—before, during and after their offences. A data-driven approach to model development, known as Grounded Theory, was undertaken to analyse the interview transcripts. A model was developed to elucidate the structural properties of sexual fantasy in the process of sexual offending, as well as the physiological and psychological variables associated with it. The Sexual Fantasy Structural Properties Model (SFSPM) comprises eight categories that describe various properties of sexual fantasy across the offence process. These categories are: origin, context, trigger, perceptual modality, clarity, motion, intensity and emotion. The strengths of the SFSPM are discussed and its clinical implications are reviewed. Finally, the limitations of the study are presented and future research directions discussed.

Incorporating differences in marginal utilities of time across activities in a time allocation model

Most existing activity time allocation models assume that individuals allocate their time to different activities over a period in such a way that the marginal utilities of time across activities are equal. Their argument is that, if not equal, an individual is free to allocate more time to those activities whose marginal utilities of time are higher and, finally allocates the optimal time to each activity with equal marginal utility. However, such an ideal situation may not always prevail in reality, especially when an individual is under income constraint and/or under intense time pressure. In order to incorporate such differences in marginal utilities of time across activities, we enrich the traditional activity time allocation model by explicitly including income constraint and by adding marginal extension activity choice model. As an application, the developed integrated model is used to estimate the value of activity time during weekends in Tokyo. The results are encouraging in that they forecast the individual time allocation more accurately and estimate realistically the value of activity time for each activity in a set of different activities than do by existing traditional models.

Structural damage identification based on self-fitting ARMAX model and multi-sensor data fusion

Statistical time series methods have proven to be a promising technique in structural health monitoring, since it provides a direct form of data analysis and eliminates the requirement for domain transformation. Latest research in structural health monitoring presents a number of statistical models that have been successfully used to construct quantified models of vibration response signals. Although a majority of these studies present viable results, the aspects of practical implementation, statistical model construction and decision-making procedures are often vaguely defined or omitted from presented work. In this article, a comprehensive methodology is developed, which essentially utilizes an auto-regressive moving average with exogenous input model to create quantified model estimates of experimentally acquired response signals. An iterative self-fitting algorithm is proposed to construct and fit the auto-regressive moving average with exogenous input model, which is capable of integrally finding an optimum set of auto-regressive moving average with exogenous input model parameters. After creating a dataset of quantified response signals, an unlabelled response signal can be identified according to a 'closest-fit' available in the dataset. A unique averaging method is proposed and implemented for multi-sensor data fusion to decrease the margin of error with sensors, thus increasing the reliability of global damage identification. To demonstrate the effectiveness of the developed methodology, a steel frame structure subjected to various bolt-connection damage scenarios is tested. Damage identification results from the experimental study suggest that the proposed methodology can be employed as an efficient and functional damage identification tool. © The Author(s) 2014.

Determination of the numerical parameters of a continuous damage model for the structural analysis of clay brick masonry

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)