947 resultados para Genotype - Environment interaction


Relevância:

30.00% 30.00%

Publicador:

Resumo:

Passion represents a strong inclination toward an activity that is important, liked, and in which significant time is invested. Although a harmonious passion is well integrated in one’s identity and is emitted willingly, obsessive passion is not well integrated and is emitted out of internal pressure. This study tested for the presence of a Passion × Environment fit interaction with respect to psychological adjustment. Elite hockey players (N = 233) who tried out for a team in a highly competitive league participated in this short-term longitudinal study. As hypothesized, being selected by the highly competitive leagues led to higher psychological adjustment than not being selected by such leagues. Two months later, an interaction revealed that among athletes who were playing in highly competitive leagues, obsessively passionate athletes reported higher psychological adjustment than did harmonious athletes. Conversely, among athletes playing in less competitive leagues, harmonious athletes reported higher psychological adjustment than did obsessive athletes.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The MFG test is a family-based association test that detects genetic effects contributing to disease in offspring, including offspring allelic effects, maternal allelic effects and MFG incompatibility effects. Like many other family-based association tests, it assumes that the offspring survival and the offspring-parent genotypes are conditionally independent provided the offspring is affected. However, when the putative disease-increasing locus can affect another competing phenotype, for example, offspring viability, the conditional independence assumption fails and these tests could lead to incorrect conclusions regarding the role of the gene in disease. We propose the v-MFG test to adjust for the genetic effects on one phenotype, e.g., viability, when testing the effects of that locus on another phenotype, e.g., disease. Using genotype data from nuclear families containing parents and at least one affected offspring, the v-MFG test models the distribution of family genotypes conditional on offspring phenotypes. It simultaneously estimates genetic effects on two phenotypes, viability and disease. Simulations show that the v-MFG test produces accurate genetic effect estimates on disease as well as on viability under several different scenarios. It generates accurate type-I error rates and provides adequate power with moderate sample sizes to detect genetic effects on disease risk when viability is reduced. We demonstrate the v-MFG test with HLA-DRB1 data from study participants with rheumatoid arthritis (RA) and their parents, we show that the v-MFG test successfully detects an MFG incompatibility effect on RA while simultaneously adjusting for a possible viability loss.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The coupling of sandy beach aquifers with the swash zone in the vicinity of the water table exit point is investigated through simultaneous measurements of the instantaneous shoreline (swash front) location, pore pressures and the water table exit point. The field observations reveal new insights into swash-aquifer coupling not previously gleaned from measurements of pore pressure only. In particular, for the case where the exit point is seaward of the observation point, the pore pressure response is correlated with the distance between the exit point and the shoreline in that when the distance is large the rate of pressure drop is fast and when the distance is small the rate decreases. The observations expose limitations in a simple model describing exit point dynamics which is based only on the force balance on a particle of water at the sand surface and neglects subsurface pressures. A new modified form of the model is shown to significantly improve the model-data comparison through a parameterization of the effects of capillarity into the aquifer storage coefficient. The model enables sufficiently accurate predictions of the exit point to determine when the swash uprush propagates over a saturated or a partially saturated sand surface, potentially an important factor in the morphological evolution of the beach face. Observations of the shoreward propagation of the swash-induced pore pressure waves ahead of the runup limit shows that the magnitude of the pressure fluctuation decays exponentially and that there is a linear increase in time lags, behavior similar to that of tidally induced water table waves. The location of the exit point and the intermittency of wave runup events is also shown to be significant in terms of the shore-normal energy distribution. Seaward of the mean exit point location, peak energies are small because of the saturated sand surface within the seepage face acting as a "rigid lid'' and limiting pressure fluctuations. Landward of the mean exit point the peak energies grow before decreasing landward of the maximum shoreline position.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This study investigated the relationship between psychosocial risk factors and (1) neck symptoms and (2) neck pain and disability as measured by the neck disability index (NDI). Female office workers employed in local private and public organizations were invited to participate, with 333 completing a questionnaire. Data were collected on various risk factors including age, negative affectivity, history of previous neck trauma, physical work environment, and task demands. Sixty-one percent of the sample reported neck symptoms lasting greater than 8 days in the last 12 months. The mean NDI of the sample was 15.5 out of 100, indicating mild neck pain and disability. In a hierarchical multivariate logistic regression, low supervisor support was the only psychosocial risk factor identified with the presence of neck symptoms. Similarly, low supervisor support was the only factor associated with the score on the NDI. These associations remained after adjustment for potential confounders of age, negative affectivity, and physical risk factors. The interaction of job demands, decision authority, and supervisor support was significantly associated with the NDI in the final model and this association increased when those with previous trauma were excluded. Interestingly, and somewhat contrary to initial expectations, as job demands increased, high decision authority had an increasing effect on the NDI when supervisor support was low. Crown copyright (c) 2006 Published by Elsevier B.V. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Long-term alcohol abuse by human subjects leads to selective brain damage that is restricted in extent and variable in severity. Within the cerebral cortex, neuronal loss is most marked in the superior frontal cortex and relatively mild in motor cortex. Cirrhotic alcoholics and subjects with alcohol-related Wernicke-Korsakoff syndrome show more severe and more extensive damage than do uncomplicated cases. Accumulating evidence suggests that the likelihood of developing alcohol dependency is associated with one or more genetic markers. In previous work we showed that GABAA receptor functionality, and the subunit isoform expression that underlies this, differed in region- and disease-specific ways between alcoholics and controls. By contrast, glutamate receptor (NMDA, KA, AMPA) differences were muted or absent. Here we asked if genotype differentiated the form, pharmacology, or expression of glutamate and GABA receptors in pathologically vulnerable and spared cortical regions, with a view to determining whether such subject factors might influence the severity of alcohol-induced brain damage. Cerebrocortical tissue was obtained at autopsy under informed, written consent from uncomplicated and alcoholic-cirrhotic Caucasian (predominantly Anglo-Celtic) cases, together with matched controls and cases with cirrhosis of non-alcoholic origin. All subjects had pathological confirmation of liver and brain diagnosis; none had been polydrug abusers. Samples were processed for synaptic membrane receptor binding, mRNA analysis by quantitative RT-PCR, and protein analysis by Western blot. Genotyping was performed by PCR methods, in the main using published primers. Several genetic markers differentiated between our alcoholic and control subjects, including the GABAA receptor 2 subunit (GABB2) gene ( 2 (3) 10.329, P 0.01), the dopamine D2 receptor B1 (DRD2B) allele ( 2 (3) 10.109, P 0.01) and a subset of the alcohol dehydrogenase-3 (ADH3) alleles ( 2 (2) 4.730, P 0.05). Although neither the type-2 glutamate transporter (EAAT2) nor the serotonin transporter (5HTT) genes were significantly associated with alcoholism, only EAAT2 heterozygotes showed a significant association between ADH3 genotype and alcoholism ( 2 (3) 7.475, P 0.05). Other interactions between genotypes were also observed. DRD2A, DRD2B, GABB2, EAAT2 and 5HTT genotypes did not divide alcoholic cases and controls on NMDA receptor parameters, although in combined subjects there was a significant DRD2B X Area Interaction with glutamateNMDA receptor efficacy (F(1,57) 4.67; P 0.05), measured as the extent of glutamate-enhanced MK801 binding. In contrast, there was a significant Case-group X ADH3 X Area Interaction with glutamateNMDA receptor efficacy (F(3,57) 2.97; P 0.05). When GABAA receptor subunit isoform expression was examined, significant Case-group X Genotype X Area X Isoform interactions were found for EAAT2 with subunit mRNA (F(1,37) 4.22; P0.05), for GABB2 with isoform protein (F(1,37) 5.69; P 0.05), and for DRD2B with isoform protein (F(2,34)5.69; P0.05). The results suggest that subjects’ genetic makeup may modulate the effectiveness of amino acid-mediated transmission in different cortical regions, and thereby influence neuronal vulnerability to excitotoxicity.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

With the increasing demand on healthcare systems it is imperative that all care is provided as efficiently and effectively as possible. Technology within the medical domain offers an exciting opportunity to augment work practices in order to meet these needs. This research project explores the implications of the interrupt-driven nature of work in clinical situations on documentation within an environment that increasingly involves electronic health records (EHRs). Midwives in a busy maternity ward were observed and interviewed about the work practices they employed to document information associated with patient care. The results showed that the interrupt-driven nature of the workplace, a feature common to many healthcare settings, led to a tension between the work and the work to document the work. Further, the IT environment in which the information was collected was not designed to cater for frequent interruption of the data entry process. Several recommendations for improving the IT environment are proposed to support health professionals in documenting patient data whilst attending to the interruptions. The recommendations include timeout screens, push technology, use of handheld PDAs, and cues to augment documentation in an interrupted session. Copyright © 2008 RMIT Publishing

Relevância:

30.00% 30.00%

Publicador:

Resumo:

There is still a great deal of opportunity for research on contextual interactive immersion in virtual heritage environments. The general failure of virtual environment technology to create engaging and educational experiences may be attributable not just to deficiencies in technology or in visual fidelity, but also to a lack of contextual and performative-based interaction, such as that found in games. However, there is little written so far on exactly how game-style interaction can help improve virtual learning environments.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Serotonin can modulate the activity of neural reward pathways that are strongly implicated in mediating the effects of chronic alcohol misuse, and its treatment, in human subjects. In previous work and as discussed elsewhere at this meeting, we and others have found consistent differences in the parameters of GABA and glutamate receptors, and the expression of their component subunit transcripts and proteins, in areas of the alcoholic brain that are altered by alcoholism. We did not fi nd clear changes in GABA and glutamate transport function in such samples, but a series of microarray analyses showed consistent upregulation of the presynaptic GABA/betaine transporter SLC6A12. Microarray studies showed no signifi cant differences in the expression of transcripts associated with 5HT transmission; however, only a small number of such elements were present on the arrays. Here we partitioned GABAA and NMDA pharmacology, and subunit mRNA and protein expression, measured in samples of frontal and motor cortex obtained at autopsy from alcoholics without comorbid disease, alcoholics with liver cirrhosis, and controls, according to 5HTTLPR (SLC6A4) and 5HT1B (HTR1B) polymorphisms. We found no effect of these genotypes on the expression of GABAA receptor gene products, but there was a signifi cant mRNA Transcript X Area X Group X 5HTTLPR Interaction with NMDA subunit isoform expression measured by Real Time PCR with GAPDH normalization. Further analysis showed the effect to be selective for alcoholics with cirrhosis, to be most marked in the pathologically vulnerable frontal cortex, and to vary with subunit transcript (F2,76 = 6.545, P = 0.002). NR1 expression was most affected, followed by NR2A, with NR2B expression least altered. Pilot data suggest 5HT1B genotype may also modulate NMDA subunit expression. Interactions between amino acid and serotonin transmission may infl uence susceptibility to alcohol dependence or pathogenesis

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Using current software engineering technology, the robustness required for safety critical software is not assurable. However, different approaches are possible which can help to assure software robustness to some extent. For achieving high reliability software, methods should be adopted which avoid introducing faults (fault avoidance); then testing should be carried out to identify any faults which persist (error removal). Finally, techniques should be used which allow any undetected faults to be tolerated (fault tolerance). The verification of correctness in system design specification and performance analysis of the model, are the basic issues in concurrent systems. In this context, modeling distributed concurrent software is one of the most important activities in the software life cycle, and communication analysis is a primary consideration to achieve reliability and safety. By and large fault avoidance requires human analysis which is error prone; by reducing human involvement in the tedious aspect of modelling and analysis of the software it is hoped that fewer faults will persist into its implementation in the real-time environment. The Occam language supports concurrent programming and is a language where interprocess interaction takes place by communications. This may lead to deadlock due to communication failure. Proper systematic methods must be adopted in the design of concurrent software for distributed computing systems if the communication structure is to be free of pathologies, such as deadlock. The objective of this thesis is to provide a design environment which ensures that processes are free from deadlock. A software tool was designed and used to facilitate the production of fault-tolerant software for distributed concurrent systems. Where Occam is used as a design language then state space methods, such as Petri-nets, can be used in analysis and simulation to determine the dynamic behaviour of the software, and to identify structures which may be prone to deadlock so that they may be eliminated from the design before the program is ever run. This design software tool consists of two parts. One takes an input program and translates it into a mathematical model (Petri-net), which is used for modeling and analysis of the concurrent software. The second part is the Petri-net simulator that takes the translated program as its input and starts simulation to generate the reachability tree. The tree identifies `deadlock potential' which the user can explore further. Finally, the software tool has been applied to a number of Occam programs. Two examples were taken to show how the tool works in the early design phase for fault prevention before the program is ever run.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The design and synthesis of biomaterials covers a growing number of biomedical applications. The use of biomaterials in biological environment is associated with a number of problems, the most important of which is biocompatabUity. If the implanted biomaterial is not compatible with the environment, it will be rejected by the biological site. This may be manifested in many ways depending on the environment in which it is used. Adsorption of proteins takes place almost instantaneously when a biomaterial comes into contact with most biological fluids. The eye is a unique body site for the study of protein interactions with biomaterials, because of its ease of access and deceptive complexity of the tears. The use of contact lenses for either vision correction and cosmetic reasons or as a route for the controlled drug delivery, has significantly increased in recent years. It is relatively easy to introduce a contact lens Into the tear fluid and remove after a few minutes without surgery or trauma to the patient. A range of analytical techniques were used and developed to measure the proteins absorbed to some existing commercial contact lens materials and also to novel hydrogels synthesised within the research group. Analysis of the identity and quantity of proteins absorbed to biomaterials revealed the importance of many factors on the absorption process. The effect of biomaterial structure, protein nature in terms of size. shape and charge and pH of the environment on the absorption process were examined in order to determine the relative up-take of tear proteins. This study showed that both lysozyme and lactoferrin penetrate the lens matrix of ionic materials. Measurement of the mobility and activity of the protein deposited into the surface and within the matrix of ionic lens materials demonstrated that the mobility is pH dependent and, within the experimental errors, the biological activity of lysozyme remained unchanged after adsorption and desorption. The study on the effect of different monomers copolymerised with hydroxyethyl methacrylate (HEMA) on the protein up-take showed that monomers producing a positive charge on the copolymer can reduce the spoilation with lysozyme. The studies were extended to real cases in order to compare the patient dependent factors. The in-vivo studies showed that the spoilation is patient dependent as well as other factors. Studies on the extrinsic factors such as dye used in colour lenses showed that the addition of colourant affects protein absorption and, in one case, its effect is beneficial to the wearer as it reduces the quantity of the protein absorbed.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

As more consumers shop online, it becomes crucial for marketers to know how online shopping environments (OSEs) can be used to gain competitive advantage. This dissertation aims to explain theoretically how OSE attributes work together holistically to produce desirable consumer responses, applying and extending a theory from the environmental psychology literature to the online context. Firstly, the study conceptualises OSEs as virtual environments which may be perceived and experienced both cognitively and affectively through a technology-mediated interaction with a computer screen. A multi-disciplinary approach identifies key characteristics of OSEs: they involve consumers; they are more complex than their offline counterparts; they are likely first apprehended holistically; and they can elicit high levels of emotions and cognition. Secondly, the research uses a gestalt approach and extends Kaplan and Kalan’s (1982) Preference Framework, taking account of the specific characteristics of OSEs, which one visits specifically to obtain product information. The results support the proposition that OSEs are perceived in terms of their Sense-making and Exploratory attributes. Thirdly, the research explains how OSE attributes work together to produce desirable consumer responses. As hypothesised, Exploratory potential produces both Hedonic and Utilitarian value, and both kinds of value contribute to Site commitment. An unexpected result is that Sense-making potential does not produce Utilitarian value directly, but only through the mediation of Exploratory potential. The research contributes to marketing theory by: (1) identifying ways the internet has changed the nature of the shopping experience; (2) extending Kaplan and Kaplan’s Preference Framework to explain how consumers perceive OSEs holistically; (3) identifying the distinction between page-level and site-level perceptions, and (4) distinguishing between different sources of information (marketer vs. non-marketer). Managerially, the research provides a model for marketers to conceive and design retail websites whose attributes work together to create competitive advantage.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

A prominent theme emerging in Occupational Health and Safety (OSH) is the development of management systems. A range of interventions, according to a prescribed route detailed by one of the management systems, can be introduced into an organisation with some expectation of improved OSH performance. This thesis attempts to identify the key influencing factors that may impact upon the process of introducing interventions, (according to B88800: 1996, Guide to Implementing Occupational Health and Safety Management Systems) into an organisation. To help identify these influencing factors a review of possible models from the sphere of Total Quality Management (TQM) was undertaken and the most suitable TQM model selected for development and use in aSH. By anchoring the aSH model's development in the reviewed literature a range ofeare, medium and low level influencing factors were identified. This model was developed in conjunction with the research data generated within the case study organisation (rubber manufacturer) and applied to the organisation. The key finding was that the implementation of an OSH intervention was dependant upon three broad vectors of influence. These are the Incentive to introduce change within an organisation which refers to the drivers or motivators for OSH. Secondly the Ability within the management team to actually implement the changes refers to aspects, amongst others, such as leadership, commitment and perceptions of OSH. Ability is in turn itself influenced by the environment within which change is being introduced. TItis aspect of Receptivity refers to the history of the plant and characteristics of the workforce. Aspects within Receptivity include workforce profile and organisational policies amongst others. It was found that the TQM model selected and developed for an OSH management system intervention did explain the core influencing factors and their impact upon OSH performance. It was found that within the organisation the results that may have been expected from implementation of BS8800:1996 were not realised. The OSH model highlighted that given the organisation's starting point, a poor appreciation of the human factors of OSH, gave little reward for implementation of an OSH management system. In addition it was found that general organisational culture can effectively suffocate any attempts to generate a proactive safety culture.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The research concerns the development and application of an analytical computer program, SAFE-ROC, that models material behaviour and structural behaviour of a slender reinforced concrete column that is part of an overall structure and is subjected to elevated temperatures as a result of exposure to fire. The analysis approach used in SAFE-RCC is non-linear. Computer calculations are used that take account of restraint and continuity, and the interaction of the column with the surrounding structure during the fire. Within a given time step an iterative approach is used to find a deformed shape for the column which results in equilibrium between the forces associated with the external loads and internal stresses and degradation. Non-linear geometric effects are taken into account by updating the geometry of the structure during deformation. The structural response program SAFE-ROC includes a total strain model which takes account of the compatibility of strain due to temperature and loading. The total strain model represents a constitutive law that governs the material behaviour for concrete and steel. The material behaviour models employed for concrete and steel take account of the dimensional changes caused by the temperature differentials and changes in the material mechanical properties with changes in temperature. Non-linear stress-strain laws are used that take account of loading to a strain greater than that corresponding to the peak stress of the concrete stress-strain relation, and model the inelastic deformation associated with unloading of the steel stress-strain relation. The cross section temperatures caused by the fire environment are obtained by a preceding non-linear thermal analysis, a computer program FIRES-T.