An improved version of white matter method for correction of non-uniform intensity in MR images: application to the quantification of rates of brain atrophy in Alzheimer's disease and normal aging

A fully automated 3D version of the so-called white matter method for correcting intensity non-uniformity in MR T1-weighted neuro images is presented. The algorithm is an extension of the original work published previously. The major part of the extension was the development of a fully automated method for the generation of the reference points. In the design of this method, a number of measures were introduced to minimize the effects of possible inclusion of non-white matter voxels in the selection process. The correction process has been made iterative. PI drawback of this approach is an increased cost in computational time. The algorithm has been tested on T1-weighted MR images acquired from a longitudinal study involving elderly subjects and people with probable Alzheimer's disease. More quantitative measures were used for the evaluation of the algorithm's performance. Highly satisfactory correction results have been obtained for images with extensive intensity non-uniformity either present in raw data or added artificially. With intensity correction, improved accuracy in the measurement of the rate of brain atrophy in Alzheimer's patients as well as in elderly people due to normal aging has been achieved

Forty years studying British politics : the decline of Anglo-America

The still present belief some 40 years ago that British politics was both exceptional and superior has been replaced by more theoretically sophisticated analyses based on a wider and more rigorously deployed range of research techniques, although historical analysis appropriately remains important. The American influence on the study of British politics has declined, but the European Union dimension has not been fully integrated. The study of interest groups has been in some respects a fading paradigm, but important questions related to democratic health have still to be addressed. Public administration has been supplanted by public policy, but economic policy remains under-studied. A key challenge for the future is the study of the management of expectations

Technical note: Development of a Linear Flow Channel Reactor for sulphur removal in acid mine wastewater treatment operations

Where sulphate removal is targeted in the biological treatment of acid mine drainage wastewaters, a step additional to sulphate reduction is required to prevent the complete oxidation of sulphide back to sulphate. This linearisation of the biological sulphur cycle has presented a technological bottleneck, particularly in passive treatment operations. We report an investigation of sulphur production in floating sulphur biofilms as a means for addressing this problem. These 50 μm to 500 μm structures may be seen to form on the surface of sulphidic, organic waters and in which sulphide is partly oxidised to So and polysulphide. A Linear Flow Channel Reactor was developed in which the formation of the floating sulphur biofilm could be optimised and studied under controlled conditions. In this study the sulphide feed was sourced from a lignocellulose packed bed reactor treating a synthetic acid mine water (2 000 mg∙ℓ-1 Na2SO4 solution) and the Liner Flow Channel Reactors (surface area 1.1 m2 and 2.2 m2) were operated in a controlled environment chamber. The floating sulphur biofilm was harvested by settling to the bottom of the reactor where it remained largely unreacted until removed. It was shown that up to 88% of sulphide in the feed stream may be removed in this way and that this was achieved mainly by oxidation of sulphide to sulphur (including a polysulphide fraction). A mass balance accounting for the process showed that up to 66% of total sulphur species entering the system were recovered as So. Oxidation of sulphide to thiosulphate and sulphate was not found to be significant. A fraction of fine particulate sulphur is released into the stream on harvesting of the biofilm which does not readily settle in the reactor and may thus be lost to the mass balance account. The effects of temperature, loading rate and reactor surface area were investigated in optimising the performance of the reactor. Scale-up application studies in the use of the Linear Flow Channel Reactor in an acid mine drainage passive treatment environment have been undertaken in field studies.Keywords: floating sulphur biofilms, acid mine drainage, AMD passive treatment, linear flow channel reactor, sulphur biotechnolog

Endogenous cholinergic inputs and local circuit mechanisms govern the phasic mesolimbic dopamine response to nicotine

Nicotine exerts its reinforcing action by stimulating nicotinic acetylcholine receptors (nAChRs) and boosting dopamine (DA) output from the ventral tegmental area (VTA). Recent data have led to a debate about the principal pathway of nicotine action: direct stimulation of the DAergic cells through nAChR activation, or disinhibition mediated through desensitization of nAChRs on GABAergic interneurons. We use a computational model of the VTA circuitry and nAChR function to shed light on this issue. Our model illustrates that the α4β2-containing nAChRs either on DA or GABA cells can mediate the acute effects of nicotine. We account for in vitro as well as in vivo data, and predict the conditions necessary for either direct stimulation or disinhibition to be at the origin of DA activity increases. We propose key experiments to disentangle the contribution of both mechanisms. We show that the rate of endogenous acetylcholine input crucially determines the evoked DA response for both mechanisms. Together our results delineate the mechanisms by which the VTA mediates the acute rewarding properties of nicotine and suggest an acetylcholine dependence hypothesis for nicotine reinforcement.Peer reviewe

Data Collection Research Methods in Applied Linguistics

The successful collection of data is a key challenge to obtaining reliable and valid results in applied linguistics research. Data Collection Research Methods in Applied Linguistics investigates how research is conducted in the field, encompassing the challenges and obstacles applied linguists face in collecting good data. The book explores frequently used data collection techniques, including: * interviews and focus groups * observations * stimulated recall and think aloud protocols * data elicitation tasks * corpus methods * questionnaires * validated tests and measures Each chapter focuses on one type of data collection, outlining key concepts, threats to reliability and validity, procedures for good data collection, and implications for researchers. The chapters also include exemplary research projects, showcasing and explaining for readers how the technique was used to collect data in a successfully published study. This book is an essential resource for both novice and experienced applied linguists tackling data collection techniques for the first time

An investigation into the mechanism underlying enhanced hydrolysis of complex carbon in a biosulphidogenic recycling sludge bed reactor (RSBR)

The potential for using readily available and cost-effective complex carbon sources such as primary sewage sludge for a range of biological processes, including the bioremediation of acid mine drainage, has been constrained by the slow rate of solubilisation and low yield of soluble products, which drive the above mentioned processes. Previous research into the hydrolysis of complex organic matter, such as primary sludge, under biosulphidogenic conditions within a novel Recycling Sludge Bed Reactor (RSBR) demonstrated solubilisation in excess of 50%. However, further investigation was required into the mechanism of this enhanced hydrolysis. The current study was aimed at confirming that hydrolysis is enhanced under biosulphidogenic conditions, and to obtain an estimate of the relative rates of hydrolysis using toluene as a specific metabolic inhibitor. The solubilisation of primary sewage sludge under sulphate reducing conditions was conducted in controlled flask studies and previously reported findings of enhanced hydrolysis were confirmed. The maximum percentage solubilisation obtained in this study over a 10-day period was 31% and 64% for the methanogenic and sulphidogenic systems respectively. By using toluene as an inhibitor of bacterial uptake of soluble carbohydrates, it was possible to determine the rate of production of various key products of the hydrolytic step. From the results of the current experiment, the rate of production of soluble carbohydrate, and therefore the rate of hydrolysis of complex carbohydrates, in terms of COD equivalents was estimated at 543 mgCOD·l-1·d-1 and 156 mgCOD·l- 1·d-1 under sulphidogenic and methanogenic conditions, respectively.. Water SA Vol. 30 (5) 2005: pp.150-15

Is equal access to higher education in South Asia and sub-Saharan Africa achievable by 2030?

Higher education is back in the spotlight, with post-2015 sustainable development goals emphasising equality of access. In this paper, we highlight the long distance still to travel to achieve the goal of equal access to higher education for all, with a focus on poorer countries which tend to have lower levels of enrolment in higher education. Analysing Demographic and Health Survey data from 35 low- and middle-income countries in sub-Saharan Africa and South Asia, we show wide wealth inequalities in particular, with few if any of the poorest gaining access to higher education in some countries. We further identify that wealth and gender inequalities interact and tend to be wider in countries where levels of higher education are higher. This implies that expansion in access to higher education may predominantly benefit the rich, unless measures are taken to tackle inequalities. We find that that the rates of increase necessary for the attainment of the equal access goal by 2030 are particularly high. They pose a particularly difficult challenge given the access inequalities present from primary and secondary education in a wide majority of countries in our analysis. We therefore suggest that any measures aimed at attaining the goal need to tackle inequalities in access within a system-wide approach, focusing on the level of education at which inequalities initially manifest, alongside higher education.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s10734-016-0039-

Bowel cancer screening in England: a qualitative study of GPs' attitudes and information needs

BACKGROUND: The National Health Service Bowel Cancer Screening Programme is to be introduced in England during 2006. General Practitioners are a potentially important point of contact for participants throughout the screening process. The aims of the study were to examine GPs' attitudes and information needs with regard to bowel cancer screening, with a view to developing an information pack for primary care teams that will be circulated prior to the introduction of the programme. METHODS: 32 GPs participated in semi-structured telephone interviews. 18 of these had participated in the English Bowel Screening Pilot, and 14 had not. Interviews covered attitudes towards the introduction of the Bowel Cancer Screening Programme, expected or actual increases in workload, confidence in promoting informed choice, and preferences for receiving information about the programme. RESULTS: GPs in the study were generally positive about the introduction of the Bowel Cancer Screening Programme. A number of concerns were identified by GPs who had not taken part in the pilot programme, particularly relating to patient welfare, patient participation, and increased workload. GPs who had taken part in the pilot reported holding similar concerns prior to their involvement. However, in many cases these concerns were not confirmed through GPs experiences with the pilot. A number of specific information needs were identified by GPs to enable them to provide a supportive role to participants in the programme. CONCLUSION: The study has found considerable GP support for the introduction of the new Bowel Cancer Screening Programme. Nonetheless, GPs hold some significant reservations regarding the programme. It is important that the information needs of GPs and other members of the primary care team are addressed prior to the roll-out of the programme so they are equipped to promote informed choice and provide support to patients who consult them with queries regarding screening

The International-Trade Network: Gravity Equations and Topological Properties

This paper begins to explore the determinants of the topological properties of the international - trade network (ITN). We fit bilateral-trade flows using a standard gravity equation to build a "residual" ITN where trade-link weights are depurated from geographical distance, size, border effects, trade agreements, and so on. We then compare the topological properties of the original and residual ITNs. We find that the residual ITN displays, unlike the original one, marked signatures of a complex system, and is characterized by a very different topological architecture. Whereas the original ITN is geographically clustered and organized around a few large-sized hubs, the residual ITN displays many small-sized but trade-oriented countries that, independently of their geographical position, either play the role of local hubs or attract large and rich countries in relatively complex trade-interaction patterns