24 resultados para Diseases and adverse factors

em Aston University Research Archive


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This article tests whether macroeconomic variables and market sentiment influence the size of momentum profits. It finds that although returns to the winner and loser portfolios are influenced by a range of macroeconomic and market wide variables; momentum profits are influenced only by the scale of portfolio outflows. Thus, when investors are sending their capital elsewhere, reduced funds at home, dampen the profitability of the momentum trading strategy. It also finds that when the market closes, below its opening level in the previous six months, momentum profits are higher, which might be a reflection of mean reversion in the market. © 2004 Taylor and Francis Ltd.

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The role of oxidation in the development of age-related eye disease has prompted interest in the use of nutritional supplementation for prevention of onset and progression. Our aim is to highlight possible contraindications and adverse reactions of isolated or high dose ocular nutritional supplements. Web of Science and PubMed database searches were carried out, followed by a manual search of the bibliographies of retrieved articles. Vitamin A should be avoided in women who may become pregnant, in those with liver disease, and in people who drink heavily. Relationships have been found between vitamin A and reduced bone mineral density, and beta-carotene and increased risk of lung cancer in smoking males. Vitamin E and Ginkgo biloba have anticoagulant and anti-platelet effects respectively, and high doses are contraindicated in those being treated for vascular disorders. Those patients with contraindications or who are considered at risk of adverse reactions should be advised to seek specialist dietary advice via their medical practitioner. © 2005 The College of Optometrists.

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The opening up of the Chinese economy and the associated transfer of technology from abroad have been taking place at an accelerating pace. Technology is crucial to China's industrial development. It is a productive resource and has a vital role in the process of economic and social development. This article provides an overview of technology transfer into China, focusing on recent developments, and examines the macroenvironmental and microenvironmental influences which foreign enterprises must consider when making investments or technology transfer decisions. Cases of companies engaged in international technology transfer are used to illustrate the discussion on the microenvironment. To be successful, foreign investors and suppliers of technology must respond to China's industrial priorities and pursue projects that are compatible with the country's broad policy goals as well as the corporate objectives of Chinese partners. The article concludes by listing a number of points to which attention should be paid before a decision is made to transfer technology to China.

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AIMS: To investigate the influence of chemical and physical factors on the rate and extent of germination of Clostridium difficile spores. METHODS AND RESULTS: Germination of C. difficile spores following exposure to chemical and physical germinants was measured by loss of either heat or ethanol resistance. Sodium taurocholate and chenodeoxycholate initiated germination together with thioglycollate medium at concentrations of 0.1-100 mmol l(-1) and 10-100 mmol l(-1) respectively. Glycine (0.2% w/v) was a co-factor required for germination with sodium taurocholate. There was no significant difference in the rate of germination of C. difficile spores in aerobic and anaerobic conditions (P > 0.05) however, the initial rate of germination was significantly increased at 37 degrees C compared to 20 degrees C (P < 0.05). The optimum pH range for germination was 6.5-7.5, with a decreased rate and extent of germination occurring at pH 5.5 and 8.5. CONCLUSIONS: This study demonstrates that sodium taurocholate and chenodeoxycholate initiate germination of C. difficile spores and is concentration dependant. Temperature and pH influence the rate and extent of germination. SIGNIFICANCE AND IMPACT OF THE STUDY: This manuscript enhances the knowledge of the factors influencing the germination of C. difficile spores. This may be applied to the development of potential novel strategies for the prevention of C. difficile infection.

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In construction projects, the aim of project control is to ensure projects finish on time, within budget, and achieve other project objectives. During the last few decades, numerous project control methods have been developed and adopted by project managers in practice. However, many existing methods focus on describing what the processes and tasks of project control are; not on how these tasks should be conducted. There is also a potential gap between principles that underly these methods and project control practice. As a result, time and cost overruns are still common in construction projects, partly attributable to deficiencies of existing project control methods and difficulties in implementing them. This paper describes a new project cost and time control model, the project control and inhibiting factors management (PCIM) model, developed through a study involving extensive interaction with construction practitioners in the UK, which better reflects the real needs of project managers. A set of good practice checklist is also developed to facilitate implementation of the model. © 2013 American Society of Civil Engineers.

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This study was undertaken for two primary purposes. The first was to discover whether or not two of the four cultural dimensions depicted by Hof-stede (1980), namely Power Distance and Uncertainty Avoidance, could be repeated using samples from seven organizations operating in three distinct cultural settings. The second was to assess the degree to which these dimensions affect superior-subordinate communication across the culturally-different groups. Also, the impact of the three interpersonal factors: Trust in Superior, Upward Influence and Mobility Aspirations was investigated cross-culturally. Participants were 291 managers from seven organizations; four Sudanese, two white British and an organization in Britain run by a group of British citizens of Pakistani extraction. It was hypothesized that the Power Distance and Uncertainty Avoidance of the three groups would replicate Hof-stede's. Specific implications of these dimensions for organizational communication and in particular for superior-subordinate communication were also hypothesized. Multiple regression analyses were performed with items of the two cultural dimensions and the three interpersonal factors (each in turn) forming the independent variables, while the organizational communication aspects formed the dependent variables. T-tests between means were also used to compare and contrast issues such as directionality of information flow across organizations operating in these settings. Work-related values of each of the three cultural groups provided support for Hofstede's model. However, only tentative support was given to the hypothesized relationships between the cultural dimensions and organizational communication. Similarly, weak associations were found between the three interpersonal factors and superior-subordinate communication behaviour. Some practical and theoretical implications are offered. An evaluation of the study and recommendation for further research are also given.

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By addressing the vascular features that characterise myopia, this thesis aims to provide an understanding of the early structural changes associated with human myopia and the progression to co-morbidity with age. This thesis addresses three main areas of study: 1. Ocular perfusion features and autoregulatory mechanisms in human myopia; 2. Choroidal thickness at the macular area of myopic eyes; 3. Effect of chronic smoking on the ocular haemodynamics and autoregulation. This thesis demonstrated a reduced resting ocular pulse amplitude and retrobulbar blood flow in human myopia, associated with an apparent oversensitivity to the vasodilatory effects of hypercapnia, which may be due to anatomical differences in the volume of the vessel beds. In young smokers, normal resting state vascular characteristics were present; however there also appeared to be increased reactivity to hypercapnia, possibly due to relative chronic hypoxia. The systemic circulation in myopes and smokers over-reacted similarly to hypercapnia suggesting that physiologic differences are not confined to the eye. Age also showed a negative effect on autoregulatory capacity in otherwise normal eyes. Collectively, these findings suggest that myopes and smokers require greater autoregulatory capacity to maintain appropriate oxygenation of retinal tissue, and since the capacity for such regulation reduces with age, these groups are at greater risk of insufficient autoregulation and relative hypoxia with age.

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The work utilising a new material for contact lenses has fallen into three parts: Physioloeical considerations: Since the cornea is devoid of blood vessels, its oxygen is derived from the atmosphere. Early hydrophilic gel contact lenses interrupted the flow of oxygen and corneal insult resulted. Three techniques of fenestration were tried to overcome this problem. High speed drilling with 0.1 mm diameter twist drills. was found to be mechanically successful, but under clinical conditions mucous blockage of the fenestrations occurred. An investigation was made into the amount of oxygen arriving at the corneal interface; related to gel lens thickness. The results indicated an improvement in corneal oxygen as lens thickness was reduced. The mechanism is thought to be a form of mechanical pump. A series of clinical studies con:firmed the experimental work; the use of thin lenses removing the symptoms of corneal hypoxia. Design: The parameters of lens back curvature. lens thickness and lens diameter have been isolated and related to three criteria of vision (a) Visual acuity. (b) Visual stability and (c) Induced astigmatism. From the results achieved a revised and basically successful design of lens has been developed. Comparative study: The developed form of lens was compared with traditional lenses in a controlled survey. Twelve factors were assessed over a twenty week period of wear using a total of eighty four patients. The results of this study indicate that whilst the expected changes were noted with the traditional lens wearers, gel lens wearers showed no discernible change in any of the factors measured. ldth the exception of' one parameter. In addition to a description of' the completed l'iork. further investigations are ·sug~ested l'lhich. it is hoped. l'iould further improve the optical performance of gel lenses.

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A study was carried out of 45 migrainous patients with visually induced migraine (VIM), and 25 migrainous students, each having an age and sex matched control. The study utilised questionnaires, interviews, electroencephalography (EEG) and visual evoked potentials (VEP). The experimental work and analysis was carried out in the Neuropsychology Unit in collaboration with the Birmingham Migraine Clinic, over a period of five years. The study suggests: 1. The literature on a possible relationship between migraine and epilepsy hitherto published is unreliable (supporting evidence is given). 2. That a much greater precision is needed in defining migraine for research purposes. 3. A revised methodology for the selection of controls is needed and this is proposed. 4. That despite what are now seen to be superficial similarities, there are clear distinctions of a fundamental nature between photo-sensitive epilepsy (PSE) and VIM. 5. Caution be used when taking headache as a symptom, since many of the precipitants of migrainous headache can also precipitate non-migrainous headache (NMH). 6. The list of visual precipitants of migraine is expanded (particularly flicker and pattern). 7. That colour (principally red) is a previously unreported precipitant of migraine. 8. The extended range of responses to flicker (the 'H' response) has no significant difference in its frequency of occurrence in patients and normal controls, which contradicts previous literature. 9. The mechanisms thought to underlie migraine serve to explain previously unexplained EEG findings. 10. Further research is needed and proposed.

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