Showing papers by "Queen's University Belfast published in 1995"
TL;DR: RMATRX1 as mentioned in this paper is a general program to calculate atomic continuum processes using the R -matrix method, including electronatom and electron-ion scattering, and radiative processes such as bound-bound transitions, photoionization and polarizabilities.
679 citations
TL;DR: In this paper, an exploratory study which has monitored a group of students' expectations and perceptions of service quality over time has been conducted, focusing on the role of the student as the primary consumer of higher education services.
Abstract: Discusses aspects of current service quality theory in the context of British higher education (HE). Focuses on the role of the student as primary consumer of HE services (a relatively recent conceptualization in this country), and the implications of this for the management of service quality in higher education organizations (HEOs). Briefly discusses an exploratory study which has monitored a group of students′ expectations and perceptions of service quality over time. Because of its limited scope, the findings of this study may not be generalized to the student population as a whole. However, it does serve to highlight the need for HEOs to gather information on students′ expectations, not only during their time at university, but at the point of arrival and before, to manage students′ expectations from enrolment through to graduation, in order to align them as closely as possible with what can be delivered by way of service quality, for the student evaluation process, or upward appraisal to be dealt wi...
619 citations
TL;DR: In this article, the effect of Helicobacter pylori infection on acid secretion was examined basally and in response to gastrin-releasing peptide (GRP) and gastrin in healthy volunteers.
519 citations
TL;DR: There was evidence, assessed by differential plating using trypticase soy agar with and without additional NaCl, that sublethally injured cells were present at pressures lower than were required for death.
478 citations
TL;DR: A series of studies, conducted over the period 1989 to 1993, based on actual purchasing patterns, seeks to quantify the extent of purchase of organic food and the consumer's commitment as mentioned in this paper.
Abstract: A series of studies, conducted over the period 1989 to 1993, based on actual purchasing patterns, seeks to quantify the extent of purchase of organic food and the consumer's commitment. The most commonly expressed motives for purchasing organic food have become consideration for the environment and health reasons. Availability and price are the chief factors which inhibit the purchase of organic food. A profile of actual purchasers of organic produce shows them to be female aged 30-45, with children and having a higher level of disposable income. This research has demonstrated that the primary factor in organic food purchase is the consumer's level of personal disposable income. There would appear to be a distinction between those who claim to be interested in the environment and those who regularly buy organic products.
464 citations
TL;DR: In 265 Irish pedigrees, with linkage analysis, evidence for a vulnerability locus for schizophrenia in region 6p24–22 is found, and this locus appears to influence the vulnerability to schizophrenia in roughly 15 to 30% of ourPedigrees.
Abstract: In 265 Irish pedigrees, with linkage analysis we find evidence for a vulnerability locus for schizophrenia in region 6p24-22 The greatest lod score, assuming locus heterogeneity, is 351 (P = 00002) with D6S296 Another test, the C test, also supported linkage, the strongest results being obtained with D6S296 (P = 000001), D6S274 (P = 0004) and D6S285 (P = 0006) Non-parametric analysis yielded suggestive, but substantially weaker, findings This locus appears to influence the vulnerability to schizophrenia in roughly 15 to 30% of our pedigrees Evidence for linkage was maximal using an intermediate phenotypic definition and declined when this definition was narrowed or was broadened to include other psychiatric disorders
457 citations
TL;DR: Seminal plasma from infertile men has lower antioxidant levels than that of fertile men, particularly of patients whose semen have poor sperm motility, and the presence of reactive oxygen species activity in sperm of infertiles groups also is associated with lower levels of chain-breaking antioxidants in seminal plasma.
345 citations
TL;DR: The location of the "spacer-receptor" unit in a 4-aminonaphthalimide fluorophore, which undergoes internal charge transfer in the excited state, is crucial for the suitability of the compound as a pH sensor as discussed by the authors.
Abstract: The location of the “spacer–receptor” unit in a 4-aminonaphthalimide fluorophore, which undergoes internal charge transfer in the excited state, is crucial for the suitability of the compound as a pH sensor. In studies of the pH dependence of the fluorescence of the regioisomers 1 and 2, only 1 displayed desirable properties.
309 citations
TL;DR: In this article, the performance of a single plane biplane Wells turbine with or without guide vanes is compared with a wave energy device based on the principle of the oscillating water-air column.
286 citations
TL;DR: In this article, the adsorption of the three metal ions, copper, cadmium and zinc in single component and multi-component mixtures in aqueous solutions by lignite is reported.
Abstract: The adsorption of the three metal ions, copper, cadmium and zinc in single component and multi-component mixtures in aqueous solutions by lignite is reported. A comparison is made between the single component saturation uptake and the multi-component uptakes. The isotherms indicate a competitive uptake with copper being preferentially absorbed by the lignite in multi-component solutions. The isotherms are plotted to obtain the Langmuir constants, the Freundlich constants and the Redlich–Peterson constants. Lignite is shown to possess an affinity for the metal ions which make its use as an adsorbent a possible alternative to the use of more expensive activated carbons.
270 citations
TL;DR: Comparing the resolution and applicability of allozyme, mitochondrial DNA and minisatellite markers for studies on population structuring, genetic variation within populations, and the impact of the accidental and deliberate introduction of non-native salmonids on the genetic make-up of natural populations is compared.
Abstract: The main molecular techniques which can be used to generate genetic markers, and the applications of these markers to studies of fish populations are outlined. Published and ongoing studies, in the authors' laboratories, on brown trout and Atlantic salmon are used to compare the resolution and applicability of allozyme, mitochondrial DNA and minisatellite (variable number of tandem repeats) markers for studies on population structuring, genetic variation within populations, and the impact of the accidental and deliberate introduction of non-native salmonids on the genetic make-up of natural populations.
TL;DR: Overall, total antioxidant capacity of serum was increased in dialysis patients, but there was a marked reduction after hemodialysis, and depletion of key chain-breaking antioxidants may lead to accelerated atherogenesis.
Abstract: Cardiovascular disease is the major cause of mortality in patients receiving hemodialysis for chronic renal failure. Increased lipid peroxidation and depletion of chain-breaking antioxidants may contribute to increased risk of atherosclerosis. We have therefore assessed the effect of a single episode of hemodialysis on antioxidant status in 22 patients and control subjects. Overall, total antioxidant capacity of serum was increased in dialysis patients, but there was a marked reduction after hemodialysis [571 +/- 31 vs 342 +/- 22 mumol/L Trolox (water-soluble vitamin E analog) equivalents, P < 0.001]. The increase in total antioxidant capacity before hemodialysis was almost entirely due to relatively high serum urate. Among individual chain-breaking antioxidants, dialysis led to a decrease in urate (398 +/- 15 vs 136 +/- 12 mumol/L, P < 0.001), ascorbate (10.5 +/- 1.7 vs 5.9 +/- 1.0 mumol/L, P < 0.01), and lipid-corrected tocopherol (4.70 +/- 0.56 vs 4.26 +/- 0.39 mumol/mmol cholesterol, P < 0.05). Protein thiol groups increased after dialysis (328 +/- 16 vs 422 +/- 22 mumol/L, P < 0.001), whereas albumin remained unchanged (40.1 +/- 1.1 vs 41.0 +/- 1.6 g/L, not significant). Although total antioxidant capacity of serum is increased in hemodialysis patients, depletion of key chain-breaking antioxidants may lead to accelerated atherogenesis.
TL;DR: The presence of systemic endotoxaemia, its correlation with disease activity, disease extent, and endotoxin core antibody concentration and the detection of circulating TNF and soluble TNF receptors all support a pathogenic role for endotoxins in IBD.
Abstract: Quantitative and qualitative disturbances in faecal flora suggest a role for enteric bacteria and their products in the pathogenesis of inflammatory bowel disease (IBD). This study investigated the hypothesis that systemically circulating endotoxins are of pathogenic significance in IBD by measuring antibody, cytokine, and acute phase protein responses. Systemic endotoxaemia was found in 88% patients with ulcerative colitis (n = 25) and 94% with Crohn's disease (n = 31) during clinical relapse. Systemic endotoxaemia correlated positively with anatomic extent and clinical activity of ulcerative colitis. Circulating tumour necrosis factor (TNF) was detected in 40% of patients with ulcerative colitis and 45% with Crohn's disease. Plasma TNF concentrations correlated with clinical and laboratory measures of disease activity and were associated with a surgical outcome to the disease episode. Plasma soluble TNF receptor p55 concentration correlated positively with disease activity and endotoxin core antibody concentrations. Plasma IgG endotoxin core antibody concentrations were significantly increased in patients with Crohn's disease and correlated with systemic endotoxaemia. The presence of systemic endotoxaemia, its correlation with disease activity, disease extent, and endotoxin core antibody concentration and the detection of circulating TNF and soluble TNF receptors all support a pathogenic role for endotoxins in IBD.
01 May 1995
TL;DR: In this article, a comparison of the integrated primary productivity signal (estimated by the 14C technique and from changes in ambient surface-water [tCO2] and [NO3−]s during the spring blooms of the two years revealed close similarities.
Abstract: The functioning of the biological pump during spring blooms was assessed with biogeochemical data from JGOFS (Joint Global Ocean Flux Study) process studies in the NE Atlantic during 1989 and 1990. A comparison of the integrated primary productivity signal (estimated by the 14C technique and from changes in ambient surface-water [tCO2] and [NO3−]s during the spring blooms of the two years revealed close similarities. These observations suggest that the magnitude of the biological drawdown of CO2 via photosynthetic activity during these periods was comparable. However, despite similarities in the magnitudes of these and other surface rate processes, sediment trap particulate organic carbon (POC) fluxes at 3100 m representing the spring bloom settlement events were 1.8 times greater in 1989 than in 1990. Taking into account the spatial and temporal resolutions of pelagic and deep trap datasets, these observations suggest that the coupling between organic carbon production in surface waters and its transfer to the deep ocean was stronger in the period studied in 1989 than in 1990. That is, the biological pump was more efficient in 1989. The size of the dominant phytoplankton species was observed to be the principal difference between the two spring bloom data sets. The potential influence of the observed algal size differences on the vertical POC flux was quantified from size-fractionated productivity data in conjuction with a food web-vertical flux model. The derived POC fluxes from the surface layer were two times greater in spring 1989 than in the bloom period in 1990, and a comparison of these flux estimates with those from other methods is favourable. Extrapolation of these derived shallow POC fluxes to 3100 m with existing empirical algorithms yields deep POC fluxes that are consistent with those collected by sediment traps at this depth. Differences in algal size between the two spring blooms can thus account for the observed interannual differences in deep-water POC fluxes without the need to invoke interannual differences in unmeasured mid-water processes. This work provides a clear demonstration that although observations of oceanic productivity may yield the input to the biological pump, they cannot, on annual timescales, reliably provide information on the efficiency of the pump in transferring carbon to the deep ocean.
TL;DR: In this article, the authors provide a framework and a suite of case studies for the elaboration of a historical geography of science, and draw attention to some implications that a spatialised historiography has for understanding the history of the geographical tradition itself.
Abstract: In recent times there has been a remarkable spatial turn within a variety of academic discourses. Historians, social theorists, anthropologists, and philosophers have all redrawn attention to the constitutive significance of place and space, site and situation, locality and territoriality. After briefly sketching some of the major features of this ‘geographical recovery’, I examine some of its implications for the study of the scientific enterprise. Such issues as the regionalisation of scientific style, the political topography of scientific commitment, and the social and material spaces of laboratories and scientific societies are considered, These materials provide both a framework and a suite of case studies for the elaboration of a historical geography of science. Last, I briefly draw attention to some implications that a spatialised historiography has for understanding the history of the geographical tradition itself.
TL;DR: The purpose of this paper is to provide an alternative view, namely, that the terms are not synonomous, and there should be different definitions for each, and the definitions that this paper provides stem from important concepts in emotional and psychological development.
TL;DR: The Se/GSHPx pattern of the FF seems to be significant for the evaluation of the follicular milieu, and patients with unexplained infertility had significantly decreased follicular selenium levels as compared with those with tubal infertility or male factor.
TL;DR: There is a need to identify more clearly the quantity and type of activity which is appropriate for children’s health and well-being, and to improve assessment techniques.
Abstract: The fitness and physical activity levels of children and youth are commonly questioned, but the evidence cited is both equivocal and methodologically diverse. The amount and type of physical activity undertaken during childhood that is appropriate for optimal health is unknown, although it has been suggested that, in the absence of such criteria, activity levels known to confer health benefits in adults are also appropriate for children. The measurement of activity in children is problematical, and there is currently no valid method of assessing activity levels that is feasible for use in large studies. Therefore, studies may lack either internal validity or wider applicability.
TL;DR: A total of 289 Listeria monocytogenes strains isolated from a poultry-processing environment and poultry products over a 6-month period were characterized by random amplification of polymorphic DNA, (RAPD) to pinpoint sources of contamination within the plant and gain some measure of the persistence of individual genotypes within this environment.
Abstract: A total of 289 Listeria monocytogenes strains isolated from a poultry-processing environment and poultry products over a 6-month period were characterized by random amplification of polymorphic DNA, (RAPD) to pinpoint sources of contamination within the plant and gain some measure of the persistence of individual genotypes within this environment. Eighteen RAPD profiles (A through R) were identified within this group, with 64% (184 of 289) of all strains displaying a single RAPD profile, RAPD type A. This genotype was more prevalent in the raw-poultry-processing environment, where, although its origin within this environment appeared to be the incoming birds, it was also widespread on food contact surfaces, floors, and drains. This was the only genotype which persisted throughout the entire 6-month period, and it and RAPD type B were the only two genotypes found in both the raw- and cooked-poultry-processing environments. L. monocytogenes strains isolated from cooked poultry products and the cooked-poultry-processing environment up to 1 year later (17 strains) contained only RAPD types A and B, highlighting the potential which exists for persistent strains to cross-contaminate foods processed in that environment. The other genotypes (C through R) occurred more sporadically, suggesting varied sources of contamination. These were confined to either the raw- or the cooked-poultry-processing environment and were relatively short-lived. Further characterization of a selection of RAPD type A strains, together with strains of RAPD types B through R, was carried out by multilocus enzyme electrophoresis. Strains of RAPD type A contained two electrophoretic types, one of which was serotype 1/2a and the other was 1/2c.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: In this article, the histological and ultrastructural evidence of various stages in microaneurysm formation within the retinal vasculature was provided, including thin walled, cellular forms to dense, acellular, hyalinised forms.
Abstract: BACKGROUND--Although microaneurysms are a clinicopathological hallmark of diabetic retinopathy, there have been few ultrastructural studies of these important lesions. As a result, knowledge of the mechanisms involved in the pathogenesis of microaneurysms remains fragmentary. This study provides histological and ultrastructural evidence of various stages in microaneurysm formation within the retinal vasculature. METHODS--The eyes of three type II diabetic patients, obtained within 24 hours of death, were studied by the trypsin digest technique. Eyes from two further type II diabetics were fixed in 2.5% glutaraldehyde within 12 hours of death and processed for electron microscopy. RESULTS--In the trypsin digest preparations, small saccular and fusiform microaneurysms were observed in the peripheral retinal. In the central retina, the microaneurysms ranged in morphology from thin walled, cellular forms to dense, acellular, hyalinised forms. Ultrastructurally, four distinct groups of microaneurysm were observed. Type I showed an extensive accumulation of polymorphonuclear cells into the lumen. The endothelium remained intact, although pericytes were invariably absent. Type II microaneurysms were typified by large numbers of red blood cells (RBCs) in the lumen. Endothelial cells and pericytes were completely absent. The type III microaneurysm was also non-perfused and contained aggregates of irregularly shaped RBC profiles and RBC breakdown products. Recanalisation by new vessels into the occluded lumen was observed in one microaneurysm. Type IV microaneurysms were almost or completely sclerosed, with extensive fibrosis and lipid infiltration into the lumen and basement membrane wall. CONCLUSION--This investigation describes several distinctive stages in the formation of microaneurysms during diabetic retinopathy. With reference to the pathogenesis of retinal microaneurysms, the interaction of various cell types is discussed and the significance of vascular cell death and localised hypertensive events highlighted.
TL;DR: In this article, a model for the long-term evolution of barrier structures and facies patterns is proposed, showing that the non-linear dynamics that appear to dominate large-scale behaviour may limit predictability.
TL;DR: The metabolism of the organophosphonate herbicide glyphosate was investigated in 163 environmental bacterial strains, obtained by a variety of isolation strategies from sites with or without prior exposure to the compound, and no evidence for its metabolism or co-metabolism to AMPA was obtained.
Abstract: The metabolism of the organophosphonate herbicide glyphosate was investigated in 163 environmental bacterial strains, obtained by a variety of isolation strategies from sites with or without prior exposure to the compound. Isolates able to use glyphosate as sole phosphorus source were more common at a treated site, but much less abundant than those capable of using the glyphosate metabolite aminomethylphosphonic acid (AMPA). Nevertheless, all 26 strains found to metabolise the herbicide did so via an initial cleavage of its carbon-phosphorus bond to yield sarcosine; no evidence for its metabolism or co-metabolism to AMPA was obtained.
TL;DR: Using a series of stratigraphically related high-precision radiocarbon measure ments, the date of a known-age eruption has been satisfactorily estimated.
Abstract: Tephra from historic and prehistoric eruptions of Oraefajokull and Hekla, Iceland, have been found in Irish peats Using a series of stratigraphically related high-precision radiocarbon measure ments, the date of a known-age eruption has been satisfactorily estimated Based on the same techniques, the calendrical date of the Hekla 4 eruption has been estimated as 2310 ± 20 BC
TL;DR: There is a dose-related association between high-strength pancreatic enzyme preparations and fibrosing colonopathy and there was an association between the occurrence of fibrosinopathy and use of high- strength pancreatic enzymes preparations in the 12 months before surgery.
TL;DR: H pylori infection may be independently associated with the development of ischaemic heart disease but if this is so the mechanism by which this effect is exerted is not through increased concentration of plasma fibrinogen.
Abstract: OBJECTIVE--To determine whether Helicobacter pylori infection is associated with the development of ischaemic heart disease and whether such infection can explain the social class inequality in ischaemic heart disease. DESIGN--Cardiovascular risk factor levels, prevalence of ischaemic heart disease (Rose questionnaire angina, and/or a history of myocardial infarction), and serum antibodies to H pylori (enzyme linked immunosorbent assay) were assessed in a cross sectional population based survey. SETTING--Belfast and surrounding districts, Northern Ireland. PARTICIPANTS--1182 men and 1198 women aged 25-64 years randomly selected from the Central Services Agency's general practitioner lists. MAIN OUTCOME MEASURES--The relation of H pylori infection with cardiovascular risk factors and ischaemic heart disease. The association of social class with ischaemic heart disease. RESULTS--Systolic and diastolic blood pressure, plasma viscosity, and total cholesterol were not associated with H pylori infection. A weak negative association existed between H pylori infection and fibrinogen (mean (SE) difference in fibrinogen between infected and uninfected individuals -0.09 (0.04) g/l, P = 0.02) and between infection in women and high density lipoprotein (HDL) cholesterol (mean (SE) difference in HDL cholesterol between infected and uninfected individuals -0.06 (0.02) mmol/l, P = 0.006). A potentially important association was demonstrated between H pylori infection and ischaemic heart disease but this did not reach statistical significance (odds ratio (95% confidence interval (CI) 1.51 (0.93 to 2.45), P = 0.1). Social class was associated with ischaemic heart disease independently of cardiovascular risk factors and H pylori infection (odds ratio, manual v non-manual (95% CI) 1.82 (1.14 to 2.91), P = 0.01). CONCLUSION--H pylori may be independently associated with the development of ischaemic heart disease but if this is so the mechanism by which this effect is exerted is not through increased concentration of plasma fibrinogen. H pylori infection does not explain the social class inequality in ischaemic heart disease which exists independently of known cardiovascular risk factors.
TL;DR: The data show that the C-terminal coding sequence of the nucleocapsid gene, although highly variable between strains, is stable in a given strain and does not appear to diverge in tissue culture, which provides a good 'signature' sequence for specific genotypes.
Abstract: The nucleotide sequence encoding the C terminus of the nucleocapsid protein of measles virus (MV) is the most variable in the genome. The sequence of this region is reported for 21 new MV strains and for virus RNA obtained from cases of subacute panencephalitis (SSPE) tissue. The nucleotide sequence of a total of 65 MV strains has been analysed using the CLUSTAL program to determine the relationships between the strains. An unrooted tree shows that eight different genotypes can be discerned amongst the sequences analysed so far. The data show that the C-terminal coding sequence of the nucleocapsid gene, although highly variable between strains, is stable in a given strain and does not appear to diverge in tissue culture. It therefore provides a good ‘signature’ sequence for specific genotypes. The sequence of this region can be used to discriminate new imported viruses from old ‘endemic’ strains of MV in a geographical area. The different genotypes are not geographically restricted although some appear to be the mainly ‘endemic’ types in large areas of the world. In global terms there appears to be at least four cocirculating genotypes of MV. The low level of divergence in the Edmonston lineage group isolated before 1970 indicates that some isolates are probably laboratory contaminants. This applies to some SSPE isolates such as the Halle, Mantooth and Horta-Barbosa strains as well as some wild-type isolates from that period.
TL;DR: In this article, a flexible three-output, two-input cost function model is used to examine the cost efficiency of UK universities as producers of teaching and research 'outputs'. Unlike previous studies, a comprehensive peer review of research quality is incorporated.
Abstract: SUMMARY A flexible three-output, two-input cost function model is used to examine the cost efficiency of UK universities as producers of teaching and research 'outputs'. Unlike previous studies, a comprehensive peer review of research quality is incorporated. Overall, product-specific and input-specific economies of scale, global and product-specific economies of scope, marginal costs and cost complementarities are estimated. Overall and product-specific scale results indicate considerable increasing returns, while the scope results generally suggest neither economies nor diseconomies. Sensitivity analysis is used to simulate the impact of current government policy, regarding the expansion of undergraduate teaching output, on these results.
TL;DR: Investigation of the association between overjet size and lip coverage when assessing the likelihood of traumatic injury to maxillary incisors suggests that much of the predictive value of increased overjet may be explained by inadequate lip coverage.
Abstract: This study investigated the association between overjet size and lip coverage when assessing the likelihood of traumatic injury to maxillary incisors. Eleven-hundred-and-thirty-seven 11- and 12-year-olds were examined in school for traumatic injury to their maxillary incisors. The size of overjet and the adequacy of lip coverage of the maxillary incisors was assessed for each child. One-hundred-and-sixty-seven (15 per cent) had experienced traumatic injury to their maxillary incisors. Both increased overjet and inadequate lip coverage of the maxillary incisors were found to be significant risk factors. However, inadequate lip coverage was the single most important independent predictor of traumatic injury (P < 0.001), with a relative odds ratio of 2.62. The results suggest that much of the predictive value of increased overjet may be explained by inadequate lip coverage.
TL;DR: Treatment with antioxidants can reduce both oxidative stress and protein glycation and may help to reduce the risk of developing diabetic complications, however, ascorbate can have both prooxidant and antioxidant effects in vivo, and its use in pharmacological doses should be approached with caution.
TL;DR: An initial bound state and an autoionizing state of a complex atom (or ion) which are resonantly coupled by a radiation field can both be characterized in a Floquet approach by complex quasienergies, giving rise to laser-induced degenerate states (LIDS).
Abstract: An initial bound state and an autoionizing state of a complex atom (or ion) which are resonantly coupled by a radiation field can both be characterized in a Floquet approach by complex quasienergies. For certain values of the field's intensity and frequency, the two quasienergies become equal, giving rise to laser-induced degenerate states (LIDS). This phenomenon is demonstrated by applying the ab initio, fully nonperturbative $R$-matrix Floquet theory to Ar, ${\mathrm{H}}^{\ensuremath{-}}$, and He. The general case is considered by constructing models containing discrete states and continua. Results for one- and for two-photon resonances are presented and suggestions for experimental observation are given.