20 resultados para Expected and observed heterozygosity

em Aston University Research Archive


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Maternal mind-mindedness, or the tendency to view the child as a mental agent, has been shown to predict sensitive and responsive parenting behavior. As yet the role of mind-mindedness has not been explored in the context of feeding interactions. This study evaluates the relations between maternal mind-mindedness at 6 months of infant age and subsequently observed maternal sensitivity and feeding behaviors with children at age 1 year. Maternal mind-mindedness was greater in mothers who had breast-fed compared to formula-fed. Controlling for breast-feeding, mind-mindedness at 6 months was correlated with observations of more sensitive and positive feeding behaviors at 1 year of age. Mind-mindedness was also associated with greater general maternal sensitivity in play and this general parenting sensitivity mediated the effect of mind-mindedness on more sensitive and positive feeding behaviors. Interventions to promote maternal tendency to consider their child's mental states may encourage more adaptive parental feeding behaviors. © 2014 Taylor & Francis.

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The knowledge of insulation debris generation and transport gains in importance regarding reactor safety research for PWR and BWR. The insulation debris released near the break consists of a mixture of very different fibres and particles concerning size, shape, consistence and other properties. Some fraction of the released insulation debris will be transported into the reactor sump where it may affect emergency core cooling. Experiments are performed to blast original samples of mineral wool insulation material by steam under original thermal-hydraulic break conditions of BWR. The gained fragments are used as initial specimen for further experiments at acrylic glass test facilities. The quasi ID-sinking behaviour of the insulation fragments are investigated in a water column by optical high speed video techniques and methods of image processing. Drag properties are derived from the measured sinking velocities of the fibres and observed geometric parameters for an adequate CFD modelling. In the test rig "Ring line-II" the influence of the insulation material on the head loss is investigated for debris loaded strainers. Correlations from the filter bed theory are adapted with experimental results and are used to model the flow resistance depending on particle load, filter bed porosity and parameters of the coolant flow. This concept also enables the simulation of a particular blocked strainer with CFDcodes. During the ongoing work further results of separate effect and integral experiments and the application and validation of the CFD-models for integral test facilities and original containment sump conditions are expected.

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The aim of this research was to assess the effect of oxygenated hydrocarbons on the knocking characteristics of an engine when blended with low-leaded gasoline. Alcohols, ethers, esters and ketones were tested individually and in various combinations up to an oxygen content of 4% wt/wt in a blend with Series F-7 gasoline of 90, 92, 94 and 96 RON. Tests were carried out at wide open throttle, constant speed and standard timing setting. Engine speed was varied using a dynamometer and knock was detected by two piezoelectric transducers, one on the cylinder head monitoring all four cylinders and one monitoring the cylinder most prone to knock. The engine speeds associated with trace and light knock of a continuous nature were noted. Curves were produced for each oxygenate blend of base RON used against engine speed for the two knock conditions which were compared with those produced using pure Series F-7 fuels. From this a suggested RON of the blend was derived. RON increase was less when using a higher RON base fuel in the blend. Most individual oxygenates showed similar effects in similar concentrations when their oxygen content was comparable. Blends containing more than one oxygenate showed some variation with methanol/MTBE/3 methylbutan-2-one and methanol/MTBE/4 methyl pentan-2-one knocking less than expected and methanol/MTBE/TBA also showing good knock resistance. Further tests to optimise initial findings suggested a blend of methanol and MTBE to be superior although partial replacement of MTBE by 4 methyl pentan-2-one resulted in a fuel of comparable performance. Exhaust emissions were tested for a number of oxygenated blends in 2-star gasoline. 2-star and 4-star fuels were also tested for reference. All oxygenate blends reduced carbon monoxide emissions as expected and hydrocarbon emissions were also reduced. The largest reduction in carbon monoxide occurred using a 14.5 % (1 : 1 : 1) methanol/MTBE/4 methyl pentan-2-one blend. Hydrocarbon emissions were most markedly reduced by a blend containing 25.5 % 4 methyl pentan-2-one. Power output was tested for the blends and indicated a maximum increase of about 5 % at low engine speeds. The most advantageous blends were methanol/4 methyl pentan-2-one (6 : 5) 11% in 2-star and methanol/MTBE/4 methyl pentan-2-one (6 : 3 : 2) 11% in 2-star. In conclusion methanol/MTBE (6 : 5) and (5 : 5), and various combinations of methanol/MTBE/4 methyl pentan-2-one, notably (6 : 3 : 2) gave good results in all tests conducted. CFR testing of these blends showed them to increase both RON and MON substantially.

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The frequency distribution of aggregate size of the diffuse and florid-type prion protein (PrP) plaques was studied in various brain regions in cases of variant Creutzfeldt-Jakob disease (vCJD). The size distributions were unimodal and positively skewed and resembled those of β-amyloid (Aβ) deposits in Alzheimer's disease (AD) and Down's syndrome (DS). The frequency distributions of the PrP aggregates were log-normal in shape, but there were deviations from the expected number of plaques in specific size classes. More diffuse plaques were observed in the modal size class and fewer in the larger size classes than expected and more florid plaques were present in the larger size classes compared with the log-normal model. It was concluded that the growth of the PrP aggregates in vCJD does not strictly follow a log-normal model, diffuse plaques growing to within a more restricted size range and florid plaques to larger sizes than predicted. © Springer-Verlag 2005.

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The PC12 and SH-SY5Y cell models have been proposed as potentially realistic models to investigate neuronal cell toxicity. The effects of oxidative stress (OS) caused by both H2O2 and Aβ on both cell models were assessed by several methods. Cell toxicity was quantitated by measuring cell viability using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) viability assay, an indicator of the integrity of the electron transfer chain (ETC), and cell morphology by fluorescence and video microscopy, both of which showed OS to cause decreased viability and changes in morphology. Levels of intracellular peroxide production, and changes in glutathione and carbonyl levels were also assessed, which showed OS to cause increases in intracellular peroxide production, glutathione and carbonyl levels. Differentiated SH-SY5y cells were also employed and observed to exhibit the greatest sensitivity to toxicity. The neurotrophic factor, nerve growth factor (NGF) was shown to cause protection against OS. Cells pre-treated with NGF showed higher viability after OS, generally less apoptotic morphology, recorded less apoptotic nucleiods, generally lower levels of intracellular peroxides and changes in gene expression. The neutrophic factor, brain derived growth factor (BDNF) and ascorbic acid (AA) were also investigated. BDNF showed no specific neuroprotection, however the preliminary data does warrant further investigation. AA showed a 'janus face' showing either anti-oxidant action and neuroprotection or pro-oxidant action depending on the situation. Results showed that the toxic effects of compounds such as Aβ and H2O2 are cell type dependent, and that OS alters glutathione metabolism in neuronal cells. Following toxic insult, glutathione levels are depleted to low levels. It is herein suggested that this lowering triggers an adaptive response causing alterations in glutathione metabolism as assessed by evaluation of glutathione mRNA biosynthetic enzyme expression and the subsequent increase in glutathione peroxidase (GPX) levels.

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This study investigated whether Negative Affectivity (NA) causes bias in self-report measures of activity limitations or whether NA has a real, non-artifactual association with activity limitations. The Symptom Perception Hypothesis (NA negatively biases self-reporting), Disability Hypothesis (activity limitations cause NA) and Psychosomatic Hypothesis (NA causes activity limitations) were examined longitudinally using both self-report and objective activity limitations measures. Participants were 101 stroke patients and their caregivers interviewed within two weeks of discharge, six weeks later and six months post-discharge. NA and self-report, proxy-report and observed performance activity (walking) limitations were assessed at each interview. NA was associated with activity limitations across measures. Both the Disability and Psychosomatic Hypotheses were supported: initial NA predicted objective activity limitations at six weeks but, additionally, activity limitations at six weeks predicted NA at six months. These results suggest that NA both affects and is affected by activity limitations and does not simply influence reporting.

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We uncover high persistence in credit spread series that can obscure the relationship between the theoretical determinants of credit risk and observed credit spreads. We use a Markovswitching model, which also captures the stability (low frequency changes) of credit ratings, to show why credit spreads may continue to respond to past levels of credit risk, even though the state of the economy has changed. A bivariate model of credit spreads and either macroeconomic activity or equity market volatility detects large and significant correlations that are consistent with theory but have not been observed in previous studies. © 2010 Nova Science Publishers, Inc. All rights reserved.

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Objective: To examine the extent to which proxy-report measures adequately assess walking limitations and are interchangeable with self-report measures in stroke survivors. Design and Participants: Self-report, proxy-report, and observed performance measures of walking limitations were compared cross-sectionally on 3 occasions following the discharge from hospital of 101 stroke survivors. Correlations between measures, differences between mean scores, and agreement of self- and proxy reports were analyzed. Results and Conclusions: Self- and proxy-report measures correlated significantly with each other and with observed performance measures; differences between mean scores were not found. Agreement between individual self- and proxy-report pairs was poor, however, indicating that freely substituting proxy-report data for self-report data when self-report data are unavailable is inappropriate.

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The National Institute for Transport and Logistics (NITL) is Ireland’s centre of excellence for supply chain management (SCM). As part of its mission to promote the development of supply chain expertise in Irish business, it designs and delivers executive modular learning programmes. In 2004, as part of a drive to create more flexible learning opportunities for course participants, NITL designed and implemented an eLearning programme, which involved converting traditionally tutored modules to online modules. This paper describes the rationale behind this initiative and the significance of technology as an enabling tool for executive education, as well as detailing the design and implementation processes for the pilot module. The paper concludes with a critique of the expected and actual benefits realised, as well as future development considerations.

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Since 1996 direct femtosecond inscription in transparent dielectrics has become the subject of intensive research. This enabling technology significantly expands the technological boundaries for direct fabrication of 3D structures in a wide variety of materials. It allows modification of non-photosensitive materials, which opens the door to numerous practical applications. In this work we explored the direct femtosecond inscription of waveguides and demonstrated at least one order of magnitude enhancement in the most critical parameter - the induced contrast of the refractive index in a standard borosilicate optical glass. A record high induced refractive contrast of 2.5×10-2 is demonstrated. The waveguides fabricated possess one of the lowest losses, approaching level of Fresnel reflection losses at the glassair interface. High refractive index contrast allows the fabrication of curvilinear waveguides with low bend losses. We also demonstrated the optimisation of the inscription regimes in BK7 glass over a broad range of experimental parameters and observed a counter-intuitive increase of the induced refractive index contrast with increasing translation speed of a sample. Examples of inscription in a number of transparent dielectrics hosts using high repetition rate fs laser system (both glasses and crystals) are also presented. Sub-wavelength scale periodic inscription inside any material often demands supercritical propagation regimes, when pulse peak power is more than the critical power for selffocusing, sometimes several times higher than the critical power. For a sub-critical regime, when the pulse peak power is less than the critical power for self-focusing, we derive analytic expressions for Gaussian beam focusing in the presence of Kerr non-linearity as well as for a number of other beam shapes commonly used in experiments, including astigmatic and ring-shaped ones. In the part devoted to the fabrication of periodic structures, we report on recent development of our point-by-point method, demonstrating the shortest periodic perturbation created in the bulk of a pure fused silica sample, by using third harmonics (? =267 nm) of fundamental laser frequency (? =800 nm) and 1 kHz femtosecond laser system. To overcome the fundamental limitations of the point-by-point method we suggested and experimentally demonstrated the micro-holographic inscription method, which is based on using the combination of a diffractive optical element and standard micro-objectives. Sub-500 nm periodic structures with a much higher aspect ratio were demonstrated. From the applications point of view, we demonstrate examples of photonics devices by direct femtosecond fabrication method, including various vectorial bend-sensors fabricated in standard optical fibres, as well as a highly birefringent long-period gratings by direct modulation method. To address the intrinsic limitations of femtosecond inscription at very shallow depths we suggested the hybrid mask-less lithography method. The method is based on precision ablation of a thin metal layer deposited on the surface of the sample to create a mask. After that an ion-exchange process in the melt of Ag-containing salts allows quick and low-cost fabrication of shallow waveguides and other components of integrated optics. This approach covers the gap in direct fs inscription of shallow waveguide. Perspectives and future developments of direct femtosecond micro-fabrication are also discussed.

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This report details an evaluation of the My Choice Weight Management Programme undertaken by a research team from the School of Pharmacy at Aston University. The My Choice Weight Management Programme is delivered through community pharmacies and general practitioners (GPs) contracted to provide services by the Heart of Birmingham teaching Primary Care Trust. It is designed to support individuals who are ‘ready to change’ by enabling the individual to work with a trained healthcare worker (for example, a healthcare assistant, practice nurse or pharmacy assistant) to develop a care plan designed to enable the individual to lose 5-10% of their current weight. The Programme aims to reduce adult obesity levels; improve access to overweight and obesity management services in primary care; improve diet and nutrition; promote healthy weight and increased levels of physical activity in overweight or obese patients; and support patients to make lifestyle changes to enable them to lose weight. The Programme is available for obese patients over 18 years old who have a Body Mass Index (BMI) greater than 30 kg/m2 (greater than 25 kg/m2 in Asian patients) or greater than 28 kg/m2 (greater than 23.5 kg/m2 in Asian patients) in patients with co-morbidities (diabetes, high blood pressure, cardiovascular disease). Each participant attends weekly consultations over a twelve session period (the final iteration of these weekly sessions is referred to as ‘session twelve’ in this report). They are then offered up to three follow up appointments for up to six months at two monthly intervals (the final of these follow ups, taking place at approximately nine months post recruitment, is referred to as ‘session fifteen’ in this report). A review of the literature highlights the dearth of published research on the effectiveness of primary care- or community-based weight management interventions. This report may help to address this knowledge deficit. A total of 451 individuals were recruited on to the My Choice Weight Management Programme. More participants were recruited at GP surgeries (n=268) than at community pharmacies (n=183). In total, 204 participants (GP n=102; pharmacy n=102) attended session twelve and 82 participants (GP n=22; pharmacy 60) attended session fifteen. The unique demographic characteristics of My Choice Weight Management Programme participants – participants were recruited from areas with high levels of socioeconomic deprivation and over four-fifths of participants were from Black and Minority Ethnic groups; populations which are traditionally underserved by healthcare interventions – make the achievements of the Programme particularly notable. The mean weight loss at session 12 was 3.8 kg (equivalent to a reduction of 4.0% of initial weight) among GP surgery participants and 2.4 kg (2.8%) among pharmacy participants. At session 15 mean weight loss was 2.3 kg (2.2%) among GP surgery participants and 3.4 kg (4.0%) among pharmacy participants. The My Choice Weight Management Programme improved the general health status of participants between recruitment and session twelve as measured by the validated SF-12 questionnaire. While cost data is presented in this report, it is unclear which provider type delivered the Programme more cost-effectively. Attendance rates on the Programme were consistently better among pharmacy participants than among GP participants. The opinions of programme participants (both those who attended regularly and those who failed to attend as expected) and programme providers were explored via semi-structured interviews and, in the case of the participants, a selfcompletion postal questionnaire. These data suggest that the Programme was almost uniformly popular with both the deliverers of the Programme and participants on the Programme with 83% of questionnaire respondents indicating that they would be happy to recommend the Programme to other people looking to lose weight. Our recommendations, based on the evidence provided in this report, include: a. Any consideration of an extension to the study also giving comparable consideration to an extension of the Programme evaluation. The feasibility of assigning participants to a pharmacy provider or a GP provider via a central allocation system should also be examined. This would address imbalances in participant recruitment levels between provider type and allow for more accurate comparison of the effectiveness in the delivery of the Programme between GP surgeries and community pharmacies by increasing the homogeneity of participants at each type of site and increasing the number of Programme participants overall. b. Widespread dissemination of the findings from this review of the My Choice Weight Management Project should be undertaken through a variety of channels. c. Consideration of the inclusion of the following key aspects of the My Choice Weight Management Project in any extension to the Programme: i. The provision of training to staff in GP surgeries and community pharmacies responsible for delivery of the Programme prior to patient recruitment. ii. Maintaining the level of healthcare staff input to the Programme. iii. The regular schedule of appointments with Programme participants. iv. The provision of an increased variety of printed material. d. A simplification of the data collection method used by the Programme commissioners at the individual Programme delivery sites.

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Cell surface properties of the basidiomycete yeast Cryptococcus neoformans were investigated with a combination of novel and well proven approaches. Non-specific cell adhesion forces, as well as exposed carbohydrate and protein moieties potentially associated with specific cellular interaction, were analysed. Experimentation and analysis employed cryptococcal cells of different strains, capsular status and culture age. Investigation of cellular charge by particulate microelectrophoresis revealed encapsulated yeast forms of C. neoformans manifest a distinctive negative charge regardless of the age of cells involved; in turn, the neutral charge of acapsulate yeasts confirmed that the polysaccharide capsule, and not the cell wall, was responsible for this occurrence. Hydrophobicity was measured by MATH and HICH techniques, as well as by the attachment of polystyrene microspheres. All three techniques, where applicable, found C. neoformans yeast to be consistently hydrophilic; this state varied little regardless of strain and culture age. Cell surface carbohydrates and protein were investigated with novel fluorescent tagging protocols, flow cytometry and confocal microscopy. Cell surface carbohydrate was identified by controlled oxidation in association with biotin hydrazide and fluorescein-streptavidin tagging. Marked amounts of carbohydrate were measured and observed on the cell wall surface of cryptococcal yeasts. Furthermore, tagging of carbohydrates with selective fluorescent lectins supported the identification, measurement and observation of substantial amounts of mannose, glucose and N-acetyl-glucosamine. Cryptococcal cell surface protein was identified using sulfo-NHS-biotin with fluorescein-streptavidin, and then readily quantified by flow cytometry. Confocal imaging of surface exposed carbohydrate and protein revealed common localised areas of vivid fluorescence associated with buds, bud scars and nascent daughter cells. Carbohydrate and protein fluorescence often varied between strains, culture age and capsule status of cells examined. Finally, extension of protein tagging techniques resulted in the isolation and extraction of two biotinylated proteins from the yeast cell wall surface of an acapsulate strain of C.neoformans.

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The research objectives were:- 1.To review the literature to establish the factors which have traditionally been regarded as most crucial to the design of effectlve exhaust ventilation systems. 2. To design, construct, install and calibrate a wind tunnel. 3. To develop procedures for air velocity measurement followed by a comprehensive programme of aerodvnamic data collection and data analysis for a variety of conditions. The major research findings were:- a) The literature in the subject is inadequate. There is a particular need for a much greater understanding of the aerodynamics of the suction flow field. b) The discrepancies between the experimentally observed centre-line velocities and those predicted by conventional formulae are unacceptably large. c) There was little agreement between theoretically calculated and observed velocities in the suction zone of captor hoods. d) Improved empirical formulae for the prediction of centre-line velocity applicable to the classical geometrically shaped suction openings and the flanged condition could be (and were) derived. Further analysis of data revealed that: - i) Point velocity is directly proportional to the suction. flow rate and the ratio of the point velocity to the average face velocity is constant. ii) Both shape, and size of the suction opening are significant factors as the coordinates of their points govern the extent of the effect of the suction flow field. iii) The hypothetical ellipsoidal potential function and hyperbolic streamlines were found experimentally to be correct. iv) The effect of guide plates depends on the size, shape and the angle of fitting. The effect was to very approximately double the suction velocity but the exact effect is difficult to predict. v) The axially symmetric openings produce practically symmetric flow fields. Similarity of connection pieces between the suction opening and the main duct in each case is essential in order to induce a similar suction flow field. Additionally a pilot study was made in which an artificial extraneous air flow was created, measured and its interaction with the suction flow field measured and represented graphically.

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Research into FL/EFL macro-reading (the effect of the broader context of reading) has been little explored in spite of its importance in the FL/EFL reading programmes. This study was designed to build on previous work by explaining in more depth the influence of the socio-educational reading environment in an Arab university (Al-Fateh University in Tripoli, Libya) - as reported by students, upon these students' reading ability in English and Arabic (particularly the former). Certain aspects of the lecturers' reading habits and attitudes and classroom operation were also investigated. Written cloze tests in English and Arabic and self-administered questionnaires were given to 125 preliminary-year undergraduates in three faculties of Al-Fateh University on the basis of their use of English as a medium of instruction (one representing the Arts' stream and two representing the Science stream). Twenty two lecturers were interviewed and observed by an inventory technique along with twenty other preliminary-year students. Factor analysis and standard multiple regression technique were among the statistical methods used to analyse the main data. The findings demonstrate a significant relationship between reading ability in English and the reading individual and environmental variables - as defined in the study. A combination of common and different series of such predictors were found accountable for the variation (43% for the first year English specialist; 48% for the combined Medicine student sample) in the English reading tests. Also found was a significant, though not very large, relationship between reading ability in Arabic and the reading environment. Non-statistical but objective analyses, based on the present data, also revealed an overall association between English reading performance and an important number of reading environmental variables - where many `poor' users of the reading environment (particularly the academic one) obtained low scores in the English cloze tests. Accepting the limitations of a single study, it is nevertheless clear that the reading environment at the University is in need of improvement and that students' use of it also requires better guidance and training in how to use it effectively. Suggestions are made for appropriate educational changes.

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Purpose To assess the validity and repeatability of the Aston Halometer. Setting University clinic, United Kingdom. Design Prospective, repeated-measures experimental study. Methods The halometer comprises a bright light-emitting-diode (LED) glare source in the center of an iPad4. Letters subtending 0.21° (∼0.3 logMAR) were moved centrifugally from the LED in 0.05 degree steps in 8 orientations separated by 45 degrees for each of 4 contrast levels (1000, 500, 100, and 25 Weber contrast units [Cw]) in random order. Bangerter occlusion foils were inserted in front of the right eye to simulate monocular glare conditions in 20 subjects (mean age 27.7 ± 3.1 years). Subjects were positioned 2 meters from the screen in a dark room with the iPad controlled from an iPhone via Bluetooth operated by the researcher. The C-Quant straylight meter was also used with each of the foils to measure the level of straylight over the retina. Halometry and straylight repeatability was assessed at a second visit. Results Halo size increased with the different occlusion foils and target contrasts (F = 29.564, P <.001) as expected and in a pattern similar to straylight measures (F = 80.655, P <0.001). Lower contrast letters showed better sensitivity but larger glare-obscured areas, resulting in ceiling effects caused by the screen's field-of-view, with 500 Cw being the best compromise. Intraobserver and interobserver repeatability of the Aston Halometer was good (500Cw: 0.84 to 0.93 and 0.53 to 0.73) and similar to the straylight meter. Conclusion The halometer provides a sensitive, repeatable way of quantifying a patient-recognized form of disability glare in multiple orientations to add objectivity to subjectively reported discomfort glare.