Showing papers by "University of Bedfordshire published in 2007"

Synergistic Interaction in Emulsions Stabilized by a Mixture of Silica Nanoparticles and Cationic Surfactant

Abstract: Using a range of complementary experiments, a detailed investigation into the behavior of dodecane-water emulsions stabilized by a mixture of silica nanoparticles and pure cationic surfactant has been made. Both emulsifiers prefer to stabilize o/w emulsions. At high pH, particles are ineffective emulsifiers, whereas surfactant-stabilized emulsions become increasingly stable to coalescence with concentration. In mixtures, no emulsion phase inversion occurs although synergism between the emulsifiers leads to enhanced stability at either fixed surfactant concentration or fixed particle concentration. Emulsions are most stable under conditions where particles have negligible charge and are most flocculated. Freeze fracture scanning electron microscopy confirms the presence of particle flocs at drop interfaces. At low pH, particles and surfactant are good emulsifiers alone. Synergism is also displayed in these mixtures, with the extent of creaming being minimum when particles are most flocculated. Experiments have been undertaken in order to offer an explanation for the latter synergy. By determining the adsorption isotherm of surfactant on particles in water, we show that surfactant addition initially leads to particle flocculation followed by re-dispersion. Using suitable contact angle measurements at oil-water-solid interfaces, we show that silica surfaces initially become increasingly hydrophobic upon surfactant addition, as well as surfactant adsorption lowering the oil-water interfacial tension. A competition exists between the influence of surfactant on the contact angle and the tension in the attachment energy of a particle to the interface.

The relative significance of syntactic knowledge and vocabulary breadth in the prediction of reading comprehension test performance

Abstract: In the componential approach to modelling reading ability, a number of contributory factors have been empirically validated. However, research on their relative contribution to explaining performance on second language reading tests is limited. Furthermore, the contribution of knowledge of syntax has been largely ignored in comparison with the attention focused on vocabulary. This study examines the relative contribution of knowledge of syntax and knowledge of vocabulary to L2 reading in two pilot studies in different contexts ‐ a heterogeneous population studying at the tertiary level in the UK and a homogenous undergraduate group in Japan ‐ followed by a larger main study, again involving a homogeneous Japanese undergraduate population. In contrast with previous findings in the literature, all three studies offer support for the relative superiority of syntactic knowledge over vocabulary knowledge in predicting performance on a text reading comprehension test. A case is made for the robustness of structural equation modelling compared to conventional regression in accounting for the differential reliabilities of scores on the measures employed.

A social cognitive approach to burnout in elite athletes.

Abstract: The purpose of this study was to investigate athlete burnout from a social-cognitive perspective by examining the relationship between social cognitive motivational variables at the start of a season and signs of burnout in elite athletes at the end of the season. Participants were 141 (F=60, M=81) elite winter sport athletes competing in Alpine skiing, Biathlon, Nordic Combined, Nordic skiing, and Speed skating. Participants completed a comprehensive motivation assessment package at the start of the season and a further burnout inventory at season's end. Results indicated that motivational dispositions, measures of the achievement climate, perceived ability and dimensions of perfectionism were associated with burnout in a conceptually consistent manner. Furthermore, the elite athletes could be grouped into two motivational profiles based on variables measured at the start of the season, one being adaptive and the other maladaptive. At season's end, the two different motivational profiles yielded distinctively different responses on an inventory assessing signs of burnout. The current findings strengthen the claim that burnout in elite athletes may not simply be "motivation gone awry" as Gould has suggested, but an inevitable consequence of exhibiting a maladaptive motivational profile.

Elevated retinol-binding protein 4 levels are associated with metabolic syndrome in Chinese people.

Abstract: Context: High retinol-binding protein 4 (RBP4) is thought to be associated with insulin resistance in humans. However, evidence from large-scale populations about the relationship between RBP4 and metabolic diseases is scarce. Objective: We evaluated plasma RBP4 distribution and its association with metabolic syndrome (MetS) among middle-aged and older Chinese. Research Design and Methods: We evaluated plasma RBP4 in a cross-sectional sample of 3289 Chinese aged from 50 to 70 yr in Beijing and Shanghai by using an in-house developed and validated sandwich ELISA. MetS was defined according to the updated National Cholesterol Education Program Adult Treatment Panel III criteria for Asian-Americans. Results: RBP4 levels were higher in male and Beijing residents, compared with female and Shanghai participants (both P < 0.001). RBP4 levels were associated positively with body mass index, waist circumference, triglycerides, total and low-density lipoprotein cholesterol, blood pressure, fasting insulin, and home...

Communication skills in child protection: how do social workers talk to parents?

Abstract: Communication skills are fundamental to social work practice, yet there is little research on the skills that workers have or how they use them. This study analyses 24 taped interviews between social workers and an actor playing a parent (a ‘simulated client’). Two child protection scenarios with different levels of seriousness were used. On average, social workers asked many closed questions and often raised concerns. They used few reflections and rarely identified positives. In all but one interview, social workers were rated as achieving clarity over issues of concern; however, they tended to demonstrate low levels of empathy. The responses of the simulated client were rated for resistance and information disclosure. The factor that most strongly influenced simulated client responses was empathy. Empathic social workers created less resistance and increased the amount of information disclosed by clients. This was not associated with failure to identify and discuss concerns. Empathy, therefore, appears to be central to good social work communication in child protection situations. Given the comparatively low level of empathy expressed by most participants, development of skills in maintaining empathic communication while raising child protection concerns appears a priority. Practical, theoretical and training implications are discussed.

Surface properties of class ii hydrophobins from Trichoderma reesei and influence on bubble stability.

Abstract: We report the remarkable surface behavior of class II hydrophobin proteins HFBI and HFBII from Trichoderma reesei and the resulting effect that these proteins have on the stability of air bubbles t...

Washback to learning outcomes: a comparative study of IELTS preparation and university pre‐sessional language courses

Abstract: This study investigated whether dedicated test preparation classes gave learners an advantage in improving their writing test scores. Score gains following instruction on a measure of academic writ...

Market orientation and performance

Abstract: This response is prompted by Hult, Ketchen and Slater's (2005) article entitled ‘Market orientation and performance: an integration of disparate approaches.’ As a contributor to the foregoing debate in the pages of this journal to which they refer I am writing to offer some observations on the nature and implications of the research reported in their paper and to clarify my essential difficulty as a strategist with the ‘market-oriented: customer-led’ construct. Copyright © 2007 John Wiley & Sons, Ltd.

Report of resistance to the neonicotinoid insecticide imidacloprid in Trialeurodes vaporariorum (Hemiptera: Aleyrodidae)

Abstract: Susceptibilities of UK and mainland European samples of Trialeurodes vaporariorum (Westwood) to the neonicotinoid insecticide imidacloprid were investigated over a 7 year period. All 24 strains collected between 1997 and 2003 showed similar baseline levels of susceptibility to that of a known susceptible laboratory strain when exposed to a diagnostic concentration (128 mg L−1) of formulated imidacloprid. Two samples collected during 2004, one from the UK and one from The Netherlands, demonstrated reduced susceptibility at this concentration. Using dose–response assays, the presence of resistant individuals was disclosed in both these strains; some individuals were unaffected at doses high enough to induce phytotoxic effects. This report represents the first confirmed cases of neonicotinoid resistance inducing control failures in T. vaporariorum, and highlights a need for careful vigilance to sustain the effectiveness of imidacloprid and related neonicotinoid insecticides. Copyright © 2007 Society of Chemical Industry

The local lymph node assay and the assessment of relative potency: status of validation.

Abstract: For the prediction of skin sensitization potential, the local lymph node assay (LLNA) is a fully validated alternative to guinea-pig tests. More recently, information from LLNA dose-response analyses has been used to assess the relative potency of skin sensitizing chemicals. These data are then deployed for risk assessment and risk management. In this commentary, the utility and validity of these relative potency measurements are reviewed. It is concluded that the LLNA does provide a valuable assessment of relative sensitizing potency in the form of the estimated concentration of a chemical required to produce a threefold stimulation of draining lymph node cell proliferation compared with concurrent controls (EC3 value) and that all reasonable validation requirements have been addressed successfully. EC3 measurements are reproducible in both intra- and interlaboratory evaluations and are stable over time. It has been shown also, by several independent groups, that EC3 values correlate closely with data on relative human skin sensitization potency. Consequently, the recommendation made here is that LLNA EC3 measurements should now be regarded as a validated method for the determination of the relative potency of skin sensitizing chemicals, a conclusion that has already been reached by a number of independent expert groups.

Tools to think with? Towards understanding the use of computer-based support tools in policy relevant research

Abstract: As environmental science has broadened to address policy concerns, there has been an effort to transfer the perceived benefits of formal modelling to these new areas through the creation of computer-based support tools. However, a number of poorly addressed issues pose barriers to the uptake of such tools. These issues are discussed to argue that the current support tool research agenda is too focussed on hard, technical concerns and that greater emphasis needs to be given to soft, contextual aspects of design and use. To counter these deficiencies we propose a framework for research based upon the concepts of innovation and receptivity. Three different sources of innovation relevant to support tools and end-user receptivity are identified. We contend that new technologies and new techniques for manipulating them have to be translated into the pre-existing knowledge and working practices of user communities before they can be effectively employed. To illustrate the proposed framework, the paper explores the impact of one innovation source on receptivity within the context of a research project developing and applying support tool technology. The need to better understand the dimensions of innovation and how they relate to the processes that determine user receptivity to support tools is emphasised.

E-Business Adoption in SMEs: Some Preliminary Findings from Electronic Components Industry

Abstract: The lack of anticipated engagement in e-business by Small and Medium sized Enterprises (SMEs) is a rising concern to the UK government and service providers alike. This article is based on the e-adoption model to examine the current practice of e-business technology adoption in SMEs and the driving forces for and against the adoption. Through interviews with 40 owner managers in the electronic components industry, the article reveals that most of the small firms in this industry are at the lower level of the “e-adoption ladder”—predominantly using the Internet and e-mail. SMEs in this industry have not yet widely engaged in online transactions. The current level of adoption is driven by both internal and external factors, including operational benefits, industry common practice, and peer pressure. External forces such as a lack of push from suppliers and customers and a lack of strategic vision of using advanced e-business technology for competitive advantages have determinant effects on the level and scale of e-adoption in SME sector. The e-adoption ladder model is modified by incorporating the influential factors identified within this study. The findings have many implications for researchers, service providers, and policy makers.

The Mobile Phone and the Public Sphere Mobile Phone Usage in Three Critical Situations

Abstract: This article seeks to explore the influence of the mobile phone on the public sphere, in particular with regard to its effect on news agendas, gatekeepers and primary definers. Using the examples o...

Parental Substance Misuse and Child Welfare: Outcomes for Children Two Years after Referral

Abstract: This paper reports on placement and welfare outcomes for children allocated a social worker where there was a concern about parental misuse of drugs or alcohol. All files going for allocation for long term work in four London boroughs over on average one year were examined (290 families). Of the 290, 100 families with 186 children involved concerns about parental substance misuse. File studies were carried out at allocation and two years post-referral for these children. At follow-up only 46% of the children remained with their main carer, with 26% living in the wider family and 27% in the formal care system. Logistic regression found the factors associated with children remaining at home were parental heroin misuse, violence and one or more parents being a first generation immigrant; factors associated with children moving were the child being a baby identified as at risk of harm and particular combinations who misused and family structure. A rating of welfare outcome was made based on educational, emotional/behavioural and health development. At follow-up, 47% of children had no problems, 31% had continuing problems and 22% had problems in more areas than at allocation. Regression analysis found the factors associated with poor welfare outcome were children remaining at home, domestic violence, alcohol misuse and being a boy. The combination of a high proportion of children moving carer and poor outcomes for those at home suggests that attention needs to be paid to improving outcomes in this area.

Assessment of the transtheoretical model as used by dietitians in promoting physical activity in people with type 2 diabetes.

Abstract: Background The transtheoretical model of change (TTM) is an approach to behaviour change, which has been successful in increasing physical activity levels. This study examined the application of a TTM approach to increase physical activity in people with type 2 diabetes by a specialist dietitian. Methods Forty participants were recruited to either an exercise consultation interview (ECI) or a control group. All participants received a physical activity leaflet and those in the ECI group also received a one-to-one interview with a dietitian a week after their routine appointment. Both self-reported physical activity levels and stage of change were measured at baseline and after 6 weeks. Results Thirty-four participants (17 in each group) completed the study. Both groups showed an increase in physical activity levels. However, there was a significant difference in change of physical activity levels in the ECI group alone [F(1,32) = 15.99;P ≤ 0.01]. In the ECI group, eight participants increased their stage of change compared with just one in the control group. There was a highly significant difference between the ECI and control group for success rates of stage progression (P = 0.007). Conclusions A specialist dietitian with motivational interviewing and behavioural change training can successfully deliver a TTM intervention to people with diabetes that results in an increase in physical activity and stage of change. Dietitians with behavioural change skills may wish to include this approach within their practice.

Chemical respiratory allergy: opportunities for hazard identification and characterisation. The report and recommendations of ECVAM workshop 60.

Abstract: Kimber, Ian Agius, Raymond Basketter, David A Corsini, Emanuela Cullinan, Paul Dearman, Rebecca J Gimenez-Arnau, Elena Greenwell, Leona Hartung, Thomas Kuper, Frieke Maestrelli, Piero Roggen, Erwin Rovida, Costanza European Centre for the Validation of Alternative Methods Consensus Development Conference England Alternatives to laboratory animals : ATLA Altern Lab Anim. 2007 May;35(2):243-65.

Skin sensitisation and epidermal disposition: the relevance of epidermal disposition for sensitisation hazard identification and risk assessment. The report and recommendations of ECVAM workshop 59.

Abstract: This is the 59th report of a series of workshops organised by the European Centre for the Validation of Alternative Methods (ECVAM). The main goal of ECVAM, as defined in 1993 by its Scientific Advisory Committee, is to promote the scientific and regulatory acceptance of alternative methods which have scientific relevance and which reduce, refine or replace the use of laboratory animals. One of the first priorities set by ECVAM was the implementation of procedures that would enable it to become well informed about the state-of-the-art of non-animal test development and validation, and the potential for the possible incorporation of alternative tests into regulatory procedures. It was decided that this would be best achieved by the organisation of ECVAM workshops, each addressing a specific topic, and at which selected groups of independent international experts would review the current status of various types of in vitro tests and their potential uses, and make recommendations about the best ways forward. A workshop on Skin Sensitisation and Epidermal Disposition was held at ECVAM (Ispra, Italy) on 30–31 January 2006, under the chairmanship of David Basketter. The current status of approaches used to measure the disposition of chemicals in skin compartments was reviewed, with particular emphasis on proposing recommendations on how best to use such information to reduce, refine and/or eliminate the need for animal testing, according to the Three Rs principle. The key focus was the relevance of information on epidermal disposition, and how best to integrate such information into non-animal testing strategies for skin sensitisation.

Confident Interpretation of Bayesian Decision Tree Ensembles for Clinical Applications

Abstract: Bayesian averaging (BA) over ensembles of decision models allows evaluation of the uncertainty of decisions that is of crucial importance for safety-critical applications such as medical diagnostics. The interpretability of the ensemble can also give useful information for experts responsible for making reliable decisions. For this reason, decision trees (DTs) are attractive decision models for experts. However, BA over such models makes an ensemble of DTs uninterpretable. In this paper, we present a new approach to probabilistic interpretation of Bayesian DT ensembles. This approach is based on the quantitative evaluation of uncertainty of the DTs, and allows experts to find a DT that provides a high predictive accuracy and confident outcomes. To make the BA over DTs feasible in our experiments, we use a Markov Chain Monte Carlo technique with a reversible jump extension. The results obtained from clinical data show that in terms of predictive accuracy, the proposed method outperforms the maximum a posteriori (MAP) method that has been suggested for interpretation of DT ensembles