Showing papers by "Cardiff University published in 1999"

Antiseptics and Disinfectants: Activity, Action, and Resistance

Abstract: Antiseptics and disinfectants are extensively used in hospitals and other health care settings for a variety of topical and hard-surface applications A wide variety of active chemical agents (biocides) are found in these products, many of which have been used for hundreds of years, including alcohols, phenols, iodine, and chlorine Most of these active agents demonstrate broad-spectrum antimicrobial activity; however, little is known about the mode of action of these agents in comparison to antibiotics This review considers what is known about the mode of action and spectrum of activity of antiseptics and disinfectants The widespread use of these products has prompted some speculation on the development of microbial resistance, in particular whether antibiotic resistance is induced by antiseptics or disinfectants Known mechanisms of microbial resistance (both intrinsic and acquired) to biocides are reviewed, with emphasis on the clinical implications of these reports

Episodic memory, amnesia, and the hippocampal–anterior thalamic axis.

Abstract: By utilizing new information from both clinical and experimental (lesion, electrophysiological, and gene-activation) studies with animals, the anatomy underlying anterograde amnesia has been reformulated. The distinction between temporal lobe and diencephalic amnesia is of limited value in that a common feature of anterograde amnesia is damage to part of an “extended hippocampal system” comprising the hippocampus, the fornix, the mamillary bodies, and the anterior thalamic nuclei. This view, which can be traced back to Delay and Brion (1969), differs from other recent models in placing critical importance on the efferents from the hippocampus via the fornix to the diencephalon. These are necessary for the encoding and, hence, the effective subsequent recall of episodic memory. An additional feature of this hippocampal–anterior thalamic axis is the presence of projections back from the diencephalon to the temporal cortex and hippocampus that also support episodic memory. In contrast, this hippocampal system is not required for tests of item recognition that primarily tax familiarity judgements. Familiarity judgements reflect an independent process that depends on a distinct system involving the perirhinal cortex of the temporal lobe and the medial dorsal nucleus of the thalamus. In the large majority of amnesic cases both the hippocampal–anterior thalamic and the perirhinal–medial dorsal thalamic systems are compromised, leading to severe deficits in both recall and recognition.

Impaired synaptic plasticity and learning in aged amyloid precursor protein transgenic mice

Abstract: We investigated synaptic communication and plasticity in hippocampal slices from mice overexpressing mutated 695-amino-acid human amyloid precursor protein (APP695SWE), which show behavioral and histopathological abnormalities simulating Alzheimer's disease. Although aged APP transgenic mice exhibit normal fast synaptic transmission and short term plasticity, they are severely impaired in in-vitro and in-vivo long-term potentiation (LTP) in both the CA1 and dentate gyrus regions of the hippocampus. The LTP deficit was correlated with impaired performance in a spatial working memory task in aged transgenics. These deficits are accompanied by minimal or no loss of presynaptic or postsynaptic elementary structural elements in the hippocampus, suggesting that impairments in functional synaptic plasticity may underlie some of the cognitive deficits in these mice and, possibly, in Alzheimer's patients.

Heritability Estimates for Psychotic Disorders: The Maudsley Twin Psychosis Series

Abstract: Background Previous twin studies have supported a genetic contribution to the major categories of psychotic disorders, but few of these have employed operational diagnostic criteria, and no such study has been based on a sample that included the full range of functional psychotic disorders. Methods A total of 224 twin probands (106 monozygotic, 118 dizygotic) with a same-sex co-twin and a lifetime history of psychosis was ascertained from the service-based Maudsley Twin Register in London, England. Research Diagnostic Criteria psychotic diagnoses were made on a lifetime-ever basis. Main-lifetime diagnoses of DSM-III-R and International Statistical Classification of Diseases, 10th Revision schizophrenia were also made. Probandwise concordance rates and correlations in liability were calculated, and biometrical model fitting applied. Results A substantial genetic contribution to variance in liability was confirmed for the major diagnostic categories except Research Diagnostic Criteria depressive psychosis and unspecified functional psychosis, where familial transmission was confirmed, but the relative contribution of genetic and common environmental factors was unclear. Heritability estimates for Research Diagnostic Criteria schizophrenia, schizoaffective disorder, mania, DSM-III-R schizophrenia, and International Statistical Classification of Diseases, 10th Revision schizophrenia were all between 82% and 85%. None of the estimates differed significantly from any other. Conclusions Heritability estimates for schizophrenia, schizoaffective disorder, and mania were substantial and similar. Population morbid risk estimates were inferred rather than directly measured, but the results were very similar to those from studies where morbid risks were directly estimated.

Islamic banking: a study of customer satisfaction and preferences in Jordan

Abstract: The Islamic banking system is gaining momentum. Many international conventional banks have started to open branches which operate in accordance with the Islamic Shariah principles in some Islamic countries. The Islamic banking system is expected to face strong competition not only from the Islamic banks but also from well‐established conventional banks offering Islamic products and services. In this study, an attempt is made to assess the degree of customer awareness and satisfaction towards an Islamic bank in Jordan. A sample 206 respondents took part in this study. The analysis of their responses revealed a certain degree of satisfaction of many of the Islamic banks facilities and products. The respondents expressed their dissatisfaction with some of the Islamic banks services. Although the respondents indicated that they are aware of a number of specific Islamic financial products like Murabaha Musharaka and Mudaraba, they show that they do not deal with them.

CONFLICT IN MARRIAGE: Implications for Working with Couples

Abstract: ▪ Abstract The investigation of marital conflict has reached a crossroads. Over 25 years of research on marital conflict behavior yields a relatively clear picture of its topography, but its relevance for changing the marital relationship remains controversial. We can continue to amass observations in a relatively atheoretical manner and hope that patterns capable of guiding clinical activity will emerge, or we can begin creating a unified theoretical framework to indicate new directions for clinical activity and empirical investigation. Before exploring the latter option, this chapter reviews briefly the impact of marital conflict on mental, physical, and family health and what is known about the nature of conflict in marriage. After highlighting some recent theoretically grounded advances, we illustrate how conceptualizing marital conflict behavior as goal directed provides an integrative theoretical framework for treatment, prevention, and marital conflict research.

A Capital Assets Framework for Analysing Household Livelihood Strategies: Implications for Policy

Abstract: Recent analyses of poverty and well-being have broadened their focus from money-metric measures of income and consumption to livelihood strategies, in order to enhance understanding of the causes of poverty, the processes of increased well-being or impoverishment, household responses to opportunities, shocks and stresses, and the outcomes of policy interventions. The aim of this article is to assess the policy implications of adopting a household livelihood strategies framework for understanding poverty and deprivation. It will identify typical policy recommendations which emerge from a conceptualisation of household strategies as managing portfolios of capital assets, and briefly review experience with a view to assessing whether this analytical approach provides a satisfactory basis for poverty reduction policy. The discussion explicitly considers the characteristics of the household strategies adopted by, and the effects of policy on, the rural and urban poor.

The canada-uk deep submillimeter survey: first submillimeter images, the source counts, and resolution of the background

Abstract: We present the first results of a deep unbiased submillimeter survey carried out at 450 and 850 μm. We detected 12 sources at 850 μm at greater than the 3 σ level, giving a surface density of sources with S850μm>2.8 mJy of 0.49 ± 0.16 arcmin-2. If replicated over the sky, our sources would generate a background at 850 μm of 9.6 × 10−11 W m-2 sr-1, which is simeq20% of the value measured by the Far-Infrared Absolute Spectrophotometer (FIRAS) and a significant fraction of the total background radiation produced by stars. This implies, through the connection between metallicity and background radiation, that a significant fraction of all the stars that have ever been formed were formed in objects like those detected here. The combination of their large contribution to the background radiation and their extreme bolometric luminosities makes these objects excellent candidates for being proto-elliptical galaxies. Optical astronomers have recently shown that the UV luminosity density of the universe increases by a factor of simeq10 between z=0 and z=1-2 and then decreases again at higher redshifts. Using the results of a parallel submillimeter survey of the local universe, we show that both the submillimeter source density and background radiation (as detected by FIRAS) can be explained if the submillimeter luminosity density evolves in a similar way to the UV luminosity density. Thus, if these sources are elliptical galaxies in the process of formation, they are probably forming at relatively modest redshifts.

Back to nature: Changing 'worlds of production' in the food sector

Abstract: Analysis of the contemporary food system has shown a progressive displacement of ‘natural’ processes in favour of those characterized as ‘industrial.’ Thus, an instrumentalized form of nature has come to prevail within the food sector. And yet, the contemporary literature on the processes of globalization and standardization in the food system has underestimated the reassertion of more ‘natural’ products in alternative food circuits. In this paper we seek to combine understandings of the conventional food sector with analysis of alternative circuits so that we can show how different ‘worlds of production’ come together in the sphere of food production. Utilizing two case studies from Italy, we indicate that the main trajectory of development in the food sector is not towards globalized and standardized production but is towards a fragmentation of production processes in which different trends can be seen to co-exist. The status of ‘nature’ differs according to the particular productive world that dominates. However, we indicate that a growing concern for the natural component of food is driving some of the most significant changes currently running through the food sector.

The initial conditions of isolated star formation — III. Millimetre continuum mapping of pre-stellar cores

Abstract: We present the results of 1.3-mm continuum mapping observations of eight pre-stellar cores, taken with the IRAM 30-m telescope equipped with the 19-channel MPIfR bolometer array. The new 1.3-mm data, which were obtained in the `on-the-fly' mapping mode, have higher angular resolution and sensitivity than previous surveys, reaching an rms noise level of ∼ 3--9 mJy per 13-arcsec beam. The present study supports the conclusions of our previous James Clerk Maxwell Telescope (JCMT) survey and suggests that, in contrast with some theoretical predictions, most pre-stellar cores have flat inner density gradients that only approach ρ (r) ∝ r-2 beyond a few thousand au. Several of the cores have a filamentary-like morphology and are apparently fragmented in a small number (∼ 2--4) of subclumps. This implies that the initial conditions for protostellar collapse depart significantly from a singular isothermal sphere. We also note quantitative disagreement in time-scales with published ambipolar diffusion models for the quasi-static evolution of molecular cloud cores under the influence of a uniform magnetic field. We speculate that turbulent processes might help to explain our observations.

15 Micron Infrared Space Observatory observations of the 1415+52 Canada-France redshift survey field: the cosmic star formation rate as derived from deep ultraviolet, optical, mid-infrared, and radio photometry

Abstract: The Canada-France Redshift Survey 1452+52 field has been deeply imaged with the Infrared Space Observatory using ISOCAM through the LW3 filter (12-18 μm). Careful data analysis and comparison with deep optical and radio data have allowed us to generate a catalog of 78 15 μm sources with both radio and optical identifications. They are redder and lie at higher redshift than I-band-selected galaxies, with most of them being star-forming galaxies. We have considered the galaxies detected at radio and 15 μm wavelengths, which potentially include all strong and heavily extincted starbursts, up to z=1. Spectral energy distributions (SEDs) for each of the sources have been derived using deep radio, mid-IR, near-IR, optical, and UV photometry. The sources were then spectrally classified by comparing with SEDs of well-known nearby galaxies. By deriving their far-IR luminosities by interpolation, we can estimate their star formation rate (SFR) in a way that does not depend sensitively on the extinction. Between 35% and 85% of the star formation at z≤1 is related to IR emission, and the global extinction is in the range AV=0.5-0.85. While heavily extincted starbursts with SFRs in excess of 100 M☉ yr-1 constitute less than 1% of all galaxies, they contribute about 18% of the SFR density out to z=1. Their morphologies range from S0 to Sab, and more than a third are interacting systems. The SFR derived by far-IR fluxes is likely to be ~2.9 times higher than those previously estimated from UV fluxes. The derived stellar mass formed since the redshift of 1 could be too high when compared with the present-day stellar mass density. This might be due to an initial mass function in distant star-forming galaxies different from the solar neighborhood one or an underestimate of the local stellar mass density.

Matched filtering of gravitational waves from inspiraling compact binaries: Computational cost and template placement

Abstract: We estimate the number of templates, computational power, and storage required for a one-step matched filtering search for gravitational waves from inspiraling compact binaries. Our estimates for the one-step search strategy should serve as benchmarks for the evaluation of more sophisticated strategies such as hierarchical searches. We use a discrete family of two-parameter wave form templates based on the second post-Newtonian approximation for binaries composed of nonspinning compact bodies in circular orbits. We present estimates for all of the large- and mid-scale interferometers now under construction: LIGO (three configurations), VIRGO, GEO600, and TAMA. To search for binaries with components more massive than mmin=0.2M⊙ while losing no more than 10% of events due to coarseness of template spacing, the initial LIGO interferometers will require about 1.0×1011 flops (floating point operations per second) for data analysis to keep up with data acquisition. This is several times higher than estimated in previous work by Owen, in part because of the improved family of templates and in part because we use more realistic (higher) sampling rates. Enhanced LIGO, GEO600, and TAMA will require computational power similar to initial LIGO. Advanced LIGO will require 7.8×1011 flops, and VIRGO will require 4.8×1012 flops to take full advantage of its broad target noise spectrum. If the templates are stored rather than generated as needed, storage requirements range from 1.5×1011 real numbers for TAMA to 6.2×1014 for VIRGO. The computational power required scales roughly as mmin-8/3 and the storage as mmin-13/3. Since these scalings are perturbed by the curvature of the parameter space at second post-Newtonian order, we also provide estimates for a search with mmin=1M⊙. Finally, we sketch and discuss an algorithm for placing the templates in the parameter space.

Alternative methods for predicting species distribution: an illustration with Himalayan river birds

Abstract: Summary 1. Current emphasis on species conservation requires the development of specific distribution models. Several modelling methods are available, but their performance has seldom been compared. We therefore used discriminant analysis, logistic regression and artificial neural networks with environmental data to predict the presence or absence of six river birds along 180 Himalayan streams. We applied each method to calibration sites and independent test sites. With logistic regression, we compared performance in predicting presence–absence using map-derived predictors (river slope and altitude) as opposed to detailed data from a standardized river habitat survey (RHS). 2. Using the entire calibration data, overall success at predicting presence or absence was only slightly greater using artificial neural networks (89–100%) than either logistic regression (75–92%) or discriminant analysis (81–95%), and on this criterion all methods gave good performance. 3. When applied to independent test data, overall prediction success averaged 71–80%, with logistic regression marginally but significantly out-performing the other methods. Encouragingly for researchers with limited data, model performance in jack-knife tests faithfully represented performance in more rigorous validations where calibration (n = 119) and test sites (n = 61) were in separate geographical regions. 4. All three methods predicted true absences (83–92% success) better than true presences (31–44%). Results from logistic regression were the most variable across species, but positive prediction declined with increasing species rarity in each method. 5. Applications with logistic regression illustrated that significant habitat predictors varied between data sets within species. Hypotheses about causal effects by habitat structure on distribution were thus difficult to erect or test. Logistic regression also showed that detailed data from the river habitat survey substantially improved positive prediction by comparison with prediction using slope or altitude alone. 6. We conclude that discriminant analysis, logistic regression and artificial neural networks differ only marginally in performance when predicting species distributions. Model choice should therefore depend on the nature of the data, on the needs of any particular analysis, and on whether assumptions for each method are satisfied. All three methods share drawbacks due to systematic effects by species rarity on performance measures. They also share limitations due to the correlative nature of survey data often used for model development at the spatial scales required in macro-ecology and conservation biology. Tests with independent data, using a wider range of performance measures than those used traditionally, will be important in examining models and testing hypotheses for such applications.

Human Resource Management and Performance in the UK Hotel Industry

Abstract: This article examines the relationship between human resource management and performance in the UK hotel industry. Using data from over 200 hotels, the results demonstrate, first, that the relationship between HRM and performance is dependent upon the business strategy the hotel is pursuing; second, that hotels pursuing an HRM approach coupled with a quality focus within their business strategy perform best; and, finally, that HRM is more likely to contribute to competitive success where it is introduced as an integrated and coherent package, or bundle of practices.

The Canada-United Kingdom Deep Submillimeter Survey. II. First Identifications, Redshifts, and Implications for Galaxy Evolution*

Abstract: Identifications are sought for 12 submillimeter sources detected in a deep submillimeter survey. Six are securely identified, two have probable identifications, and four remain unidentified with IAB > 25. Spectroscopic and estimated photometric redshifts indicate that four of the sources have z 3. The spectral energy distributions of the identifications, as defined by measurements or upper limits to the flux densities at 8000 A, at 15, 450, 850 μm, and at 6 cm, are consistent with the spectral energy distributions of high-extinction starbursts such as Arp 220. The far-IR luminosities of the sources at z > 0.5 are of order 3 × 1012 h-250 L☉, i.e., slightly larger than that of Arp 220. As with local ultraluminous infrared galaxies, the optical luminosities of the identified galaxies are comparable to present-day L*, and the optical morphologies of many of the galaxies show evidence for mergers or highly disruptive interactions. Based on this small sample, the cumulative bolometric luminosity function shows strong evolution to z~1, but weaker or possibly even negative evolution beyond. The redshift dependence of the far-IR luminosity density does not appear, at this early stage, to be inconsistent with that seen in the ultraviolet luminosity density. Although the computation of bolometric luminosities is quite uncertain, the population of very luminous galaxies that is detected in the surveys at z > 1 is already matching, in the far-IR, the bolometric output in the ultraviolet of the whole optically selected population. Assuming that the energy source in the far-IR is massive stars, this suggests that the total luminous output from star formation in the universe will be dominated by the far-IR emission once the lower luminosity sources, below the current far-IR detection threshold, are included. Furthermore, the detected systems have individual star formation rates (exceeding 300 h-250 M☉ yr-1) that are much higher than seen in the ultraviolet-selected samples and that are sufficient to form substantial stellar populations on dynamical timescales of 108 yr. The association with mergerlike morphologies and the obvious presence of dust makes it attractive to identify these systems as forming the metal-rich spheroid population, in which case we would infer that much of this activity has occurred relatively recently, at z~2.

Rural Futures: The Consumption Countryside and its Regulation

Abstract: The paper outlines some of the main features of the ‘political and social economy of rural space’ from a British perspective. It details the trajectory of what is termed the ‘consumption countryside’ that is, the sets of increasingly diverse ruralities which tie rural space and people to the provision of goods and services that can be consumed by those in and beyond their particular boundaries. These trends have significance for the development of European rural social science; and particularly the development of a comparative rural sociology which can analyse the differentiation of rural space. In doing so, the paper suggests the need to forge a critical and interpretative set of new relations with the state (supra, national and, regional and local), and to play a much more engaging part in the differential evolution of new rural governance structures.

Framboidal Pyrite Formation by the Oxidation of Iron(II) Monosulfide by Hydrogen Sulfide

Abstract: Introduction: The ubiquity of framboidal pyrite occurrences in modern and ancient sedimentary environments and in low to medium temperature ore deposits suggests a robust formation mechanism able to operate under a range of physico-chemical conditions. Furthermore, the appearance of framboidal pyrite subjacent to the onset of anoxia in sediments and water columns is consistent with a formation mechanism which is geologically instantaneous. Finally, the highly spatially ordered microarchitecture present in many examples of framboidal pyrite (e.g. A in figure) implies a formation mechanism which permits self-organisation of individual microcrystals during framboid formation.

The role of zinc oxide in Cu/ZnO catalysts for methanol synthesis and the water–gas shift reaction

Abstract: All commercial catalysts for methanol synthesis and for the water–gas shift reaction in the low temperature region contain zinc oxide in addition to the main active component, copper. The varied benefits of zinc oxide are analysed here. The formation of zincian malachite and other copper/zinc hydroxy carbonates is essential in the production of small, stable copper crystallites in the final catalyst. Further, the regular distribution of copper crystallites on the zinc oxide phase ensures long catalyst life. Zinc oxide also increases catalyst life in the water–gas shift process by absorbing sulphur poisons but it is not effective against chloride poisons. In methanol synthesis, zinc oxide (as a base) removes acidic sites on the alumina phase which would otherwise convert methanol to dimethyl ether. Although bulk reduction of zinc oxide to metallic zinc does not take place, reduction to copper–zinc alloy (brass) can occur, sometimes as a surface phase only. A new interpretation of conflicting measurements of adsorbed oxygen on the copper surfaces of methanol synthesis catalysts is based on the formation of Cu–O–Zn sites, in addition to oxygen adsorbed on copper alone. The possible role of zinc oxide as well as copper in the mechanisms of methanol synthesis is still the subject of controversy. It is proposed that, only under conditions of deficiency of adsorbed hydrogen on the copper phase, hydrogen dissociation on zinc oxide, followed by hydrogen spillover to copper, is significant.

Functionally Dissociating Aspects of Event Memory: the Effects of Combined Perirhinal and Postrhinal Cortex Lesions on Object and Place Memory in the Rat

Abstract: Reciprocal interactions between the hippocampus and the perirhinal and parahippocampal cortices form core components of a proposed temporal lobe memory system. For this reason, the involvement of the hippocampus in event memory is thought to depend on its connections with these cortical areas. Contrary to these predictions, we found that NMDA-induced lesions of the putative rat homologs of these cortical areas (perirhinal plus postrhinal cortices) did not impair performance on two allocentric spatial tasks highly sensitive to hippocampal dysfunction. Remarkably, for one of the tasks there was evidence of a facilitation of performance. The same cortical lesions did, however, disrupt spontaneous object recognition and object discrimination reversal learning but spared initial acquisition of the discrimination. This pattern of results reveals important dissociations between different aspects of memory within the temporal lobe. Furthermore, it shows that the perirhinal–postrhinal cortex is not a necessary route for spatial information reaching the hippocampus and that object familiarity–novelty detection depends on different neural substrates than do other aspects of event memory.

Using the Information Decoupling Point to Improve Supply Chain Performance

Abstract: Traditionally, the decoupling point methodology has been associated with the material flow pipeline. However, to maximize improvement in supply chain dynamics, information flow is equally important. Many of the problems exhibited in the material flow pipeline are the result of the distortion of marketplace sales information as it is transferred upstream through the supply chain. This research expands on the traditional material decoupling point methodology and establishes the role of an information decoupling point within the supply chain. The authors demonstrate the business opportunities generated by first recognizing the existence of the supply chain information decoupling point and then learning how to utilize it to gain strategic advantage. In order to make sensible planning and delivery decisions, a business must be able to separate out contingency from real orders as they move upstream from the marketplace. It is the basis for supply chains moving towards continuous flow and away from point‐to‐point movements and ultimately, where appropriate, to holistic control.