Showing papers by "Brunel University London published in 1995"
TL;DR: It is found that effluent from sewage treatment works contains a chemical, or mixture of chemicals, that induces vitellogenin synthesis in male fish maintained in the effluent, thus indicating that the effluents is estrogenic.
Abstract: A rapidly increasing number of chemicals, or their degradation products, are being recognized as possessing estrogenic activity, albeit usually weak. We have found that effluent from sewage treatme...
1,473 citations
TL;DR: The current finding that some phthalate compounds and some food additives are weakly estrogenic in vitro, needs to be supported by further studies on their effects in vivo before any conclusions can be made regarding their possible role in the development of these conditions.
Abstract: Sewage, a complex mixture of organic and inorganic chemicals, is considered to be a major source of environmental pollution. A random screen of 20 organic man-made chemicals present in liquid effluents revealed that half appeared able to interact with the estradiol receptor. This was demonstrated by their ability to inhibit binding of 17 beta-estradiol to the fish estrogen receptor. Further studies, using mammalian estrogen screens in vitro, revealed that the two phthalate esters butylbenzyl phthalate (BBP) and di-n-butylphthalate (DBP) and a food antioxidant, butylated hydroxyanisole (BHA) were estrogenic; however, they were all less estrogenic than the environmental estrogen octylphenol. Phthalate esters, used in the production of various plastics (including PVC), are among the most common industrial chemicals. Their ubiquity in the environment and tendency to bioconcentrate in animal fat are well known. Neither BBP nor DBP were able to act as antagonists, indicating that, in the presence of endogenous estrogens, their overall effect would be cumulative. Recently, it has been suggested that environmental estrogens may be etiological agents in several human diseases, including disorders of the male reproductive tract and breast and testicular cancers. The current finding that some phthalate compounds and some food additives are weakly estrogenic in vitro, needs to be supported by further studies on their effects in vivo before any conclusions can be made regarding their possible role in the development of these conditions.
1,250 citations
Book•
04 Dec 1995TL;DR: In this paper, the authors present Freeing the Voices: A Science of the People 6. Building Sustainable Futures: Science Shops and Social Experiments 7. Science, Citizenship and Troubled Modernity
Abstract: Introduction 1. Science and Citizenship 3. Science, Citizenship and Environmental Threat 4. Witnesses, Participants and Major Accident Hazards 5. Freeing the Voices: A Science of the People 6. Building Sustainable Futures: Science Shops and Social Experiments 7. Science, Citizenship and Troubled Modernity
1,169 citations
TL;DR: In this article, the authors define a set of policy measures that constitute the "New Public Management" (NPM), and evidence is cited to support the contention that the NPM has been widely adopted.
Abstract: The article first defines a set of policy measures that constitute the 'New Public Management' (NPM). Evidence is cited to support the contention that the NPM has been widely adopted, with local va...
470 citations
TL;DR: Effluent from sewage-treatment works entering British rivers contains an estrogenic chemical, or mixture of chemicals, that stimulates vitellogenin synthesis in male fish, which causes a reduction in the rate of testicular development in trout undergoing sexual maturation.
292 citations
TL;DR: The operation and performance of an algorithm for segmenting connected points into a combination of representations such as lines, circular, elliptical and superelliptical arcs, and polynomials is described and demonstrated.
Abstract: This paper describes and demonstrates the operation and performance of an algorithm for segmenting connected points into a combination of representations such as lines, circular, elliptical and superelliptical arcs, and polynomials. The algorithm has a number of interesting properties including being scale invariant, nonparametric, general purpose, and efficient.
230 citations
TL;DR: The features of a well designed case study are described and examples showing how qualitative methods are used in evaluations of health services and health policy are given.
Abstract: Case study evaluations, using one or more qualitative methods, have been used to investigate important practical and policy questions in health care This paper describes the features of a well designed case study and gives examples showing how qualitative methods are used in evaluations of health services and health policy
227 citations
TL;DR: In this paper, a comparison between 38 mature and 60 non-mature students taking the same course found that the mature students obtained significantly higher scores on meaning orientation, and that they also tended to produce lower scores on reproducing orientation.
Abstract: Mature students are often said to be deficient in study skills, but a recent literature review by Richardson concluded that they tended to exhibit more desirable approaches to learning. Using a shortened form of the Approaches to Studying Inventory, a comparison between 38 mature and 60 non-mature students taking the same course found indeed that the mature students obtained significantly higher scores on meaning orientation, and that they also tended to produce lower scores on reproducing orientation. In addition, in terms of both their persistence and their attainment, the subsequent academic performance of the mature students on their degree courses was at least as good as that of the non-mature students.
217 citations
TL;DR: The acute histomorphometric and biochemical response of bone to severe burn injury, as well as bone mass in severely burned children, is reported here.
149 citations
TL;DR: Journal editors and readers of economic evaluation articles should acquaint themselves with the methods for handling uncertainty in order that they can critically evaluate the extent to which authors have allowed for uncertainties inherent in their analysis.
Abstract: A structured methodological review of journal articles published in 1992 was undertaken to determine whether recently published economic evaluation studies deal systematically and comprehensively with uncertainty. Ninety three journal articles were identified from a range of searches including a computerised search of the MEDLINE CD-Rom database. Articles were reviewed to determine how they had handled uncertainty in: a) data sources; b) generalisability; c) extrapolation; and d) analytic method. Articles were subsequently assessed to determine how they had represented this uncertainty in terms of the overall results of their analysis. Finally, studies were rated on the basis of their overall performance with respect to dealing systematically and comprehensively with uncertainty. Despite the numerous books and articles devoted to the appropriate methods to be employed by analysts conducting economic evaluation, 22 (24%) studies failed to consider uncertainty at all and 35 (38%) studies employed sensitivity analysis in a manner judged as inadequate. In all, 36 (39%) studies were judged to have given at least an adequate account of uncertainty with 13 (14%) of those judged to have provided a good account of uncertainty. Such disappointing results may reflect a general lack of detail in much of the methods literature concerning how sensitivity analysis should be applied and how results should be presented. Journal editors and readers of economic evaluation articles should acquaint themselves with the methods for handling uncertainty in order that they can critically evaluate the extent to which authors have allowed for uncertainties inherent in their analysis.
124 citations
TL;DR: In this article, the main practical use of these techniques is the rapid creation of a prototype from a computer program, but the longer term possibilities for ceramics include the manufacture of high-resolution mulfilayer circuits and devices, the fabrication of solid oxide fuel cells of complex design, the preparation of ordered ceramic composites for structural or piezoelectric applications and the manufacturing of highly complex small monolithic ceramic components.
Abstract: Techniques are currently being developed to allow complex shapes to be created directly from a computer program by the addition of material to, rather than the abstraction of material from, the component. These are mouldless manufacturing operations, variously known as solid free-form fabrication [1,2], rapid prototyping [3] or, more colloquially, "art to part" technology [4, 5]. Various materials processing operations have been adapted for this purpose. In laminated object manufacture (LOM), laser-cut layers of foil are stacked to produce the shape [5]. In stereolithography, an ultraviolet (UV) laser is used to scan and cure a photosensitive monomer [6]. In selective laser sintering, a more powerful laser is used to scan and sinter a deposit of ceramic, metal or polymer powder [1, 7]. Although the last process is attractive for ceramics manufacture, considerable problems of particle packing before sintering and of residual stresses set up during sintefing remain. So far, the main practical use of these techniques is the rapid creation of a prototype from a computer program, but the longer term possibilities for ceramics include the manufacture of high resolution mulfilayer circuits and devices, the fabrication of solid oxide fuel cells of complex design, the preparation of ordered ceramic composites for structural or piezoelectric applications and the manufacture of highly complex small monolithic ceramics. Previous work at Brunel University has considered manufacturing operations for ceramics in which the powder is dispersed in an organic vehicle [8, 9]. These processes do not depend on agglomerated powders and have the capability to achieve the excellent dispersion necessary for high performance ceramics [10]. Similar requirements are applicable in paint and printing operations. Recent work has shown that the random deposition of droplets of a ceramic paint can be used to produce multilayer ceramic composites [11]. Although many printing operations are used in the traditional ceramics industry, only screen printing is widely used for advanced ceramics. Jet printing [12] is a non-contact printing process in which small ( 5 × 10-13m 3) drops of ink are ejected when required from a thermal or piezoelectric activated nozzle of diameter 25-75/xm (drop on demand ink jet printing). In contrast, continuous ink jet printing uses charged drops from a continuously recycled stream, which are diverted to the substrate when required by a voltage applied to deflector plates. Ink jet technology has been used to deposit a binder solution on to layers of roll-compacted ceramic powder to fix particles in place before conventional sintering [13]. This allows the creation of a porous ceramic by computer aided manufacture (CAM). A ceramic ink was prepared by selecting a thermoplastic resin, dispersant and ceramic powder such that the ceramic occupied 60 vol% in the absence of solvent. This volume fraction was chosen to avoid shrinkage cracks [11]. It also confers thermoplastic properties to the dried ink to allow subsequent plastic forming operations if required. This composition was diluted with solvent for printing. The sources of materials and composition of the ink are given in Table I. The polyvinyl butyral
TL;DR: In this article, three main problems in "anti-essentialist" critiques of techno logical determinism are identified, all of which mean that such critiques remain committed to a form of essentialism.
Abstract: Whereas many constructivist and feminist approaches to the social study of technology share an antipathy to technological tietenninism, they offer an insufficiently radical critique of technolagy. Three main problems in "anti-essentialist" critiques of techno logical determinism are identified, all of which mean that such critiques remain committed to a form of essentialism. These characteristics recur in many recent feminist arguments about technology, illustrated by the example of reproductive technologies. To overcome weaknesses in political radicalism based on anti-essentialism, it is necessary to move to a "past-essentialist" approach. The unwillingness to do so is shown to be based on unfounded objections to "excessive" relativism.
TL;DR: In this paper, a review of the literature on nitrogen oxide concludes that the thermal nitric oxide (NO) mechanism is the most relevant to the nitrogen oxide emissions from spark ignition engines.
TL;DR: In this article, the authors search for lepton flavour violating Z0→eμ, Z 0→eτ and Z 0 →μτ decays in a sample of 4.0×106 visible Z0 decays collected with the OPAL detector at LEP during 1991 to 1994.
Abstract: We have searched for lepton flavour violating Z0→eμ, Z0→eτ and Z0→μτ decays in a sample of 4.0×106 visible Z0 decays collected with the OPAL detector at LEP during 1991 to 1994. No candidates are found for Z0→eμ. The samples of selected Z0→eτ and Z0→μτ candidates are consistent with the expected background. The following limits are set at 95% confidence level:
$$\begin{gathered} BR(Z^0 \to e\mu ){\text{ }}< {\text{ 1}}{\text{.7 }} \times {\text{ 10}}^{ - {\text{6}}} \hfill \\ BR(Z^0 \to e\tau ){\text{ }}< {\text{ 9}}{\text{.8 }} \times {\text{ 10}}^{ - {\text{6}}} \hfill \\ BR(Z^0 \to \mu \tau ){\text{ }}< {\text{ 17}}{\text{. }} \times {\text{ 10}}^{ - {\text{6}}} . \hfill \\ \end{gathered}$$
TL;DR: The construction and detailed molecular cytogenetic characterization of a panel of 23 stable hybrids, representing all 22 human autosomes plus the X-chromosome, including 18 new hybrids isolated by direct microcell transfer from normal human diploid fibroblasts into mouse A9 cells are described.
Abstract: Humamrodent somatic cell hybrids carrying a single, intact, selectable human chromosome are valuable both for functional somatic cell genetic analysis and genome mapping procedures Here, we describe
TL;DR: It is demonstrated that individuals displaying high levels of aggressive behaviour are able to monopolise access to food and that enforced swimming at a moderate speed reduces the incidence of aggression although not the degree of monopolisation of food shown by aggressive individuals.
Abstract: Although swimming is energetically costly, a number of studies on salmonid species have demonstrated increased growth rates in fishes forced to swim for prolonged periods at moderate speeds (typically 1–2 body lengths per sec). This suggests that additional energetic costs of swimming are more than met by alternative compensatory gains. The mechanisms underlying such effects are not fully understood. In this paper, we describe an experiment designed to examine one possible mechanism, namely a swimming-induced inhibition of aggression, with consequent beneficial effects on growth. The study used Arctic charr,Salvelinus alpinus, a species for which a positive relationship between exercise and growth has been clearly established. Using direct behavioural observations on small groups, we demonstrate that individuals displaying high levels of aggressive behaviour are able to monopolise access to food and that enforced swimming at a moderate speed (1 body length per sec) reduces the incidence of aggression although not the degree of monopolisation of food shown by aggressive individuals. These results suggest that the enhanced growth rates accompanying enforced swimming may reflect lower energetic costs of reduced aggressive activity rather than improved access to food by subordinates.
TL;DR: In this paper, historical and contemporary developments in feminist thinking on theory and method are considered, together with the affinity between feminist research and qualitative methods, concerning: a false dualism between quantity and quality; ethical concerns; and writing in the personal.
Abstract: Historical and contemporary developments in feminist thinking on theory and method are considered. The critique of positivism is outlined, together with the affinity between feminist research and qualitative methods. Dilemmas are raised concerning: a false dualism between quantity and quality; ethical concerns; and writing in the personal. There are contradictory positions within the contemporary argument for methodological pluralism, such that it does not resolve tensions surrounding issues of women's experience and the warranting of interpretations. Epistemological debates involving feminism and post-modernism have created a changed intellectual landscape for reconsidering the link between qualitative research and standpoint theory. These raise issues of grounding, depth and evaluating knowledge by appeals to a notion of strong (or feminist) objectivity, together with the need to mitigate against appropriation of the `other'. Exemplars of qualitative feminist analysis are presented.
TL;DR: In this article, anatase was used for the oxidation of o -xylene and o -tolualdehyde over V 2 O 5 / TiO 2 (anatase) catalysts at 533-633 K under steady state conditions.
TL;DR: Strong evidence is provided that the normal SHD X chromosome displays powerful senescence-inducing properties when introduced, by microcell transfer, into newly immortalized SHD recipients, suggesting that induction of the immortal phenotype in SHD cells by carcinogens results primarily from functional inactivation of a senescENCE gene which may be X-linked.
Abstract: Immortalization is a prerequisite for the clonal evolution and malignant transformation of normal mammalian cells in culture. In order to gain a mechanistic insight into the genetics of carcinogen-induced cellular immortality, a cell culture assay has been developed based on the use of freshly explanted Syrian hamster dermal (SHD) fibroblasts. The relative efficacies of a variety of chemical and physical carcinogens at immortalizing SHD cells (against a zero background of spontaneous immortalization) were compared. Ionizing radiation and nickel chloride appeared to be more effective as immortalizing agents than powerful point mutagens, suggesting (but not proving) that clastogenic damage may be more significant in the immortalization process than point mutation. Frequencies of induced immortality (10(-6)-10(-7)/treated cell) were arguably consistent with a direct mutational mechanism involving a single genetic target. However, detailed cytogenetic characterization of a panel of newly immortalized cell lines revealed no non-random chromosomal alterations in the cells at the level of G-banding. Furthermore, additional experiments with the SHD system have provided confirmatory evidence that immortalization can occur as an indirect consequence of carcinogen exposure following an induced high frequency change in the treated population, rather than through direct targeted mutagenesis. Previous somatic cell genetic studies have suggested the possibility that a target gene for immortalization exists on the human and Chinese hamster X chromosomes. Here we provide strong evidence that the normal SHD X chromosome displays powerful senescence-inducing properties when introduced, by microcell transfer, into newly immortalized SHD recipients. These results suggest that induction of the immortal phenotype in SHD cells by carcinogens results primarily from functional inactivation of a senescence gene which may be X-linked. One possible mechanism for senescence gene inactivation consistent with our observations is through a sub-microscopic interstitial genetic deletion. However, the considerable efficacy of nickel (a human carcinogen) as an immortalizing agent at nonmutagenic doses raises the alternative possibility that immortalization may occur through an epigenetic mechanism.
TL;DR: The successes and failures of simulation modelling in this context are examined, and an approach for improving the processes, and outcomes, by the use of soft systems methodology is suggested.
Abstract: This paper provides a review of the use of simulation for resource planning in the health sector. Case examples of simulation in health are provided, and the modelling prob lems are explored. The successes and failures of simulation modelling in this context are examined, and an approach for improving the processes, and outcomes, by the use of soft systems methodology, is suggested.
TL;DR: In this paper, the mechanical behavior of polypropylene composites containing magnesium hydroxide is considered with reference to the influence on properties of filler surface modification, and results are discussed in terms of the observed deformation mechanism in the polymer matrix.
Abstract: The mechanical behaviour of polypropylene composites containing magnesium hydroxide is considered with reference to the influence on properties of filler surface modification. Compared to composites containing untreated filler, mechanical properties can be strongly affected by the chemical nature and amount of surface treatment applied. In particular, very significant improvements in toughness are obtained using sufficiently high levels of magnesium stearate to ensure complete coverage of the magnesium hydroxide surface. Results are discussed in terms of the observed deformation mechanism in the polymer matrix.
TL;DR: In this article, the authors compared the properties of three different types of jet types: b, uds, and gluon jets, and observed that the b and uds jets have similar properties as measured by the angular distribution of particle energy around the jet directions and by the fragmentation functions.
Abstract: Symmetric three-jet events are selected from hadronic Z0 decays such that the two lower energy jets are each produced at an angle of about 150° with respect to the highest energy jet. In some cases, a displaced secondary vertex is reconstructed in one of the two lower energy jets, which permits the other lower energy jet to be identified as a gluon jet through anti-tagging. In other cases, the highest energy jet is tagged as a b jet or as a light quark (uds) jet using secondary vertex or track impact parameter and momentum information. Comparing the two lower energy jets of the events with a tag in the highest energy jet to the anti-tagged gluon jets yields a direct comparison of b, uds and gluon jets, which are produced with the same energy of about 24 GeV and under the same conditions. We observe b jets and gluon jets to have similar properties as measured by the angular distribution of particle energy around the jet directions and by the fragmentation functions. In contrast, gluon jets are found to be significantly broader and to have a markedly softer fragmentation function than uds jets. For thek
⊥ jet finder withy
cut=0.02, we find
$$\begin{gathered} \frac{{\left\langle {n^{ch.} } \right\rangle gluon}}{{\left\langle {n^{ch.} } \right\rangle b quark}} = 1.089 \pm 0.024(stat.) \pm 0.024(syst.) \hfill \\ \frac{{\left\langle {n^{ch.} } \right\rangle gluon}}{{\left\langle {n^{ch.} } \right\rangle uds quark}} = 1.390 \pm 0.038(stat.) \pm 0.032(syst.) \hfill \\ \end{gathered} $$
as the ratios of the mean charged particle multiplicity in the gluon jets compared to the b and uds jets. Results are also reported using the cone jet finder.
TL;DR: The implications of patients' approaches to managing chronic fatigue syndrome were examined, and the causal direction of relationships between coping and fatigue severity is ambiguous, and a follow-up study will address the effects of coping on changes in the illness over time.
Abstract: The implications of patients' approaches to managing chronic fatigue syndrome were examined in a cross-sectional study. With severity of fatigue controlled, attempting to maintain activity was associated with less functional impairment, while accommodating to the illness was positively related to impairment; behavioural disengagement was related not only to higher levels of impairment but also to greater emotional disturbance. Fatigue itself was positively associated with focusing on symptoms and with behavioural disengagement; it was associated also with illness accommodation, but only for illness of longer duration. The causal direction of relationships between coping and fatigue severity is ambiguous, and a follow-up study will address the effects of coping on changes in the illness over time.
TL;DR: Comparison with the clinical migration data showed a good correlation and revealed that it may be possible to use the calculated initial cancellous bone stresses to predict the migration of the implant, and hence the probability of early and mid-term aseptic loosening.
TL;DR: In this article, the effect of ascending additions of fine TiO2 powder on the porosity of a hand mixed polyurethane foam system was studied and the implications of the results for polymer foam opacifiers and flame retardants and for ceramic foam fabrication were considered.
Abstract: The effect of ascending additions of fine TiO2 powder on the porosity of a hand mixed polyurethane foam system was studied. Voidage was sustained in the 95% region up to 20 vol% powder addition based on the polymer. Loss of powder from the windows occurred below this level and a reticulate structure was obtained on sintering. Above 20 vol%, the windows remained mainly closed on sintering. The implications of the results for polymer foam opacifiers and flame retardants and for ceramic foam fabrication are considered.
TL;DR: In this article, the impact of compulsory competitive tendering (CCT) on the nature of work within public sector services has been examined in terms of their impact on the quality, reach, and cost of public services.
Abstract: The process of compulsory competitive tendering (CCT) for the provision of local-government services has forced significant changes to the way in which such services have been provided, whether such services have been contracted out or remain in-house, and has spawned a considerable literature on the impact of these changes on the quality, reach, and cost of public services. The primary focus of this literature has been on service users (or ‘consumers’) and the local taxpayer. In this paper, however, we attempt an analysis of these changes in terms of their impact on the nature of work within public sector services. Empirical evidence of geographical and sectoral variations in the degree of success of the private sector in winning contracts is considered, and explanations for these variations are offered. In particular, the discussion focuses on variations in the form of work in different sectors and the treatment of workers in different places and in different types of services, through a study of the labour processes involved and a consideration of the diverse potential for different fractions of capital to benefit from the introduction of CCT. Last, the concept of ‘hollowing out’ is reworked in order to further assist the theorisation of employment and other contemporary changes in the local state.
TL;DR: In this paper, an intensity-based optical fiber sensor was designed and evaluated under tension/tension and tension/compression fatigue loading conditions, and the feasibility of using the embedded sensor for fatigue damage detection was demonstrated.
Abstract: The detection of fatigue-induced damage within fibre-reinforced composite materials is of vital importance in areas where these materials are used for critical load-bearing applications. Embedded fibre-optic sensors are suitable for damage detection in composite materials because they can be easily integrated into the structure with minimal interference with the bulk properties of the composite. In this current study, a novel intensity-based optical fibre sensor was designed and evaluated under tension/tension and tension/compression fatigue loading conditions. This intensity sensor has the ability to monitor rapid strain changes without loss of the reference level. Furthermore, this sensor utilizes relatively simple and inexpensive instrumentation. The fibre-optic strain sensor was embedded within a 16-ply 0/90 carbon/epoxy laminate at the manufacturing stage. The embedded optical fibre sensor was not found to affect the fatigue life of the composite both under tension/tension and tension/compression loading. The feasibility of using the embedded sensor for fatigue damage detection was demonstrated. Excellent correlation was also obtained between the strain data from a surface mounted optical fibre sensor and a surface-mounted extensometer under fatigue loading conditions.
TL;DR: In this article, a multi-point distributed humidity-sensing system was constructed based on the principle of using the absorption spectrum of a colorimetric reagent (cobalt chloride) immobilized on the surface of the core of a multimode optical fiber by employing a thin gelatin film.
Abstract: A novel multi-point distributed humidity-sensing system has been constructed based on the principle of using the absorption spectrum of a colorimetric reagent (cobalt chloride) immobilized on the surface of the core of a multimode optical fibre by employing a thin gelatin film. Two-wavelength detection is employed to provide intensity referencing. Light attenuation at the reference wavelength is only 0.2 dB. The basic design, construction and testing of an experimental sensor in the humidity region 20–80% RH and temperature range 25–50 °C is described. Resolution can be better than 2% RH and the time constant is about one second. Repeatability is at least as good as the resolution of measurement. A two-wavelength optical time-domain reflectometer (OTDR) has been developed and a four-sensor network has been built. The resolution of measurement on the network can be better than 4% RH, but because of noise in the OTDR the resolution value is dependent on the averaging time in the instrument.
TL;DR: It is shown that parenteral administration of octylphenol is active in stimulating oestrogen-dependent uterine growth in prepubertal rats, but has no influence on perinatal sexual differentiation of the rat brain.
TL;DR: In this paper, a theoretical analysis of plastic flow at the pole of an elliptical bulge as it forms through a die from applying normal pressure to thin metallic sheets is presented, where the inherent anisotropy present in as-rolled sheets of three steels and a brass is characterized from in-plane r-values.