4,642 research outputs found

    A Network Model of Alcoholism and Alcohol Policy

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    The evolution of alcohol dependence in populations of people on different social networks is studied. Two models are studied. One is the evolution of the states of individuals on hypothesized social structures from a rewired connected caveman model. This model spans a range of social structures (networks) from very ordered to effectively random with small world structures in between. The second model is a zip-code-level model which uses data from a recent survey in Delaware. The model is a discrete model using 10 zip codes. The results show that the evolution of alcohol dependence, as governed by the simple rules that we use, depends sensitively on the network structure and a hypothetical treatment regime

    Replacement bearing for Rocketdyne SSME HPOTPs using alternate self-lubricating retainer materials

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    Research was conducted to develop replacement bearings for the Rocketdyne Space Shuttle main engine (SSME) high pressure oxidizer turbopumps (HPOTPs). The replacement bearings consisted of standard balls and races with a special Battelle Self-Lubricating Insert Configuration (BASIC) retainer. The BASIC retainer consists of a phosphor bronze housing with inserts consisting of a polytetrafluoretheylene (PTFE) and bronze compound. The PTFE contacts the balls and the land guiding surface on the outer race. A PTFE transfer film is formed on balls and races, which lubricates the critical interfaces. The BASIC retainer is a one-to-one replacement for the current Armalon retainer, but has superior lubricating properties and is stronger over the broad temperature range anticipated for the HPOTP bearings. As a part of the project 40 sets of balls and races (two sizes) and 52 BASIC retainers were shipped to NASA/MSFC

    Using policy analysis to explore the reciprocal impact of health policy on public health nursing and public health nursing on policy.

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    The overall aim of this study was to explore the reciprocal impact of health policy on public health nursing and public health nursing on policy. This study uses a new approach to considering public health nurses’ engagement in policy: one which puts public health nurses, as actors in the policy process, at the centre of the investigation. The overall philosophical lens through which the research was conducted was critical social theory and the methodology was a grounded theory influenced research design. The study adopted a three stage data collection and analysis process: primary data (questionnaires and interviews), detailed policy analyses of two specific White Papers and secondary data (extant documents). The data were collected and analysed through a grounded theory approach in order to answer four research questions: 1. What do public health nurses know about policy, specifically in relation to two English Department of Health White Papers: Creating A Patient-Led NHS (DOH 2005) and Our Health, Our Care, Our Say (DOH 2006)? 2. How do they engage in the policy process? 3. What affects their implementation of policy? 4. Is there a policy-practice gap? A triangulated approach to data collection and analysis was used. Primary data were collected through questionnaires and follow up telephone interviews with public health nurses (health visitors and school nurses) in four PCTs and one social enterprise in five different geographical areas of England. Further data from detailed policy analyses using frameworks by Popple and Leighninger (2008) and Walt and Gilson (1994) were also considered. Finally, secondary data from extant documents including newspapers, websites and organisational documents were reviewed. At the end of the research process, it was possible to answer the four research questions. In addition to this, new knowledge and theory emerged around three main themes: i) A proposal for a new combined framework for policy analysis which leads to a comprehensive and analytical account of policy content and context combined with a detailed consideration of the role of public health nurses as actors in the policy process. ii) Theories as to why and how public health nurses lack influence in the policy process. iii) Analysis of the effect of lack of resources on inhibiting practice innovation in response to policy agendas. Consideration of these theories led to several recommendations for practice. Throughout the research process, there was continued interaction between the three phases of data collection, analysis and theory development

    Nonstandard electroconvection in a bent-core oxadiazole material

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    Electroconvection (EC) phenomena have been investigated in the nematic phase of a bent-core oxadiazole material with negative dielectric anisotropy and a frequency dependent conductivity anisotropy. The formation of longitudinal roll (LR) patterns is one of the predominant features observed in the complete frequency and voltage range studied. At voltages much above the LR threshold, various complex patterns such as the "crisscrossed" pattern, bimodal varicose, and turbulence are observed. Unusually, the nonstandard EC (ns-EC) instability in this material, is observed in a regime in which we measure the dielectric and conductivity anisotropies to be negative and positive respectively. A further significant observation is that the EC displays distinct features in the high and low temperature regimes of the nematic phase, supporting an earlier report that EC patterns could distinguish between regions that have been reported as uniaxial and biaxial nematic phases

    An analytical approach to sorting in periodic potentials

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    There has been a recent revolution in the ability to manipulate micrometer-sized objects on surfaces patterned by traps or obstacles of controllable configurations and shapes. One application of this technology is to separate particles driven across such a surface by an external force according to some particle characteristic such as size or index of refraction. The surface features cause the trajectories of particles driven across the surface to deviate from the direction of the force by an amount that depends on the particular characteristic, thus leading to sorting. While models of this behavior have provided a good understanding of these observations, the solutions have so far been primarily numerical. In this paper we provide analytic predictions for the dependence of the angle between the direction of motion and the external force on a number of model parameters for periodic as well as random surfaces. We test these predictions against exact numerical simulations

    Knee joint neuromuscular activation performance during muscle damage and superimposed fatigue

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    This study examined the concurrent effects of exercise-induced muscle damage and superimposed acute fatigue on the neuromuscular activation performance of the knee flexors of nine males (age: 26.7 ± 6.1yrs; height 1.81 ± 0.05m; body mass 81.2 ± 11.7kg [mean ± SD]). Measures were obtained during three experimental conditions: (i) FAT-EEVID, involving acute fatiguing exercise performed on each assessment occasion plus a single episode of eccentric exercise performed on the first occasion and after the fatigue trial; (ii) FAT, involving the fatiguing exercise only and; (iii) CON consisting of no exercise. Assessments were performed prior to (pre) and at lh, 24h, 48h, 72h, and 168h relative to the eccentric exercise. Repeated-measures ANOVAs showed that muscle damage within the FAT-EEVID condition elicited reductions of up to 38%, 24%) and 65%> in volitional peak force, electromechanical delay and rate of force development compared to baseline and controls, respectively (F[io, 80] = 2.3 to 4.6; p to 30.7%>) following acute fatigue (Fp; i6] = 4.3 to 9.1; p ; Fp, iq = 3.9; p <0.05). The safeguarding of evoked muscle activation capability despite compromised volitional performance might reveal aspects of capabilities for emergency and protective responses during episodes of fatigue and antecedent muscle damaging exercise

    Activity of water in aqueous systems; A frequently neglected property

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    In this critical review, the significance of the term ‘activity’ is examined in the context of the properties of aqueous solutions. The dependence of the activity of water(ℓ) at ambient pressure and 298.15 K on solute molality is examined for aqueous solutions containing neutral solutes, mixtures of neutral solutes and salts. Addition of a solute to water(ℓ) always lowers its thermodynamic activity. For some solutes the stabilisation of water(ℓ) is less than and for others more than in the case where the thermodynamic properties of the aqueous solution are ideal. In one approach this pattern is accounted for in terms of hydrate formation. Alternatively the pattern is analysed in terms of the dependence of practical osmotic coefficients on the composition of the aqueous solution and then in terms of solute–solute interactions. For salt solutions the dependence of the activity of water on salt molalities is compared with that predicted by the Debye–Hückel limiting law. The analysis is extended to consideration of the activities of water in binary aqueous mixtures. The dependence on mole fraction composition of the activity of water in binary aqueous mixtures is examined. Different experimental methods for determining the activity of water in aqueous solutions are critically reviewed. The role of water activity is noted in a biochemical context, with reference to the quality, stability and safety of food and finally with regard to health science.

    An evaluation of earth banked tanks for slurry storage

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    End of project reportThis study examines the feasibility of using earth-banked tanks (EBT’s) as an alternative and economical means of winter storage for animal and other farmyard wastes. The study contains a detailed literature review on the subject, the results of a series of laboratory-scale experiments, field studies and a predictive model of the transport process through the soil liner of an earth-banked tank

    European Retrofit Network: Retrofitting Evaluation Methodology Report

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    The research programme, funded by the EU Progress Fund, looks at the potential impacts of construction training in the area of „retrofitting‟ social housing to make it more sustainable, in particular to improve energy efficiency and reduce greenhouse gas emissions. This report investigates methodologies for measuring and demonstrating carbon emissions reductions resulting from retrofitting measures in the partner countries (UK, Spain, Poland and Montenegro). The output of this part of the study is a methodology appropriate to measuring the likely carbon reduction impacts through common retrofit measures in the social housing sector, taking into account the likely cost effectiveness of measures, the impact on occupants, the project management challenges and thus the measures that are most likely to be employed in policy and practice. An appropriate methodology is one that can be applied across the range of different conditions found in the partner countries (representative to some degree of the range of conditions found across Europe as whole). Low carbon retrofit has been defined as „incremental improvements to the building fabric and systems with primary intention of improving energy efficiency and reducing carbon emissions.

    Evaluation of Milking Systems in Terms of Mastitis Risk, Teat Tissue Reactions & Milking Performance.

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    End of Project ReportsMeasurements of milking vacuum recorded on a flow simulator can provide guidelines for optimum design of milking units. • Increasing the bore of the short milk tube above the recommended diameter or claw volume above 150ml does not improve milking efficiency. • Increasing the long milk-tube bore from 13.5mm to 16mm increased the level of milking vacuum. • The milking vacuum was highest with wide-bore tapered liners and simultaneous pulsation. • The minimum vacuum was increased with narrow-bore liners and alternate pulsation. • The milk yield with wide-bore tapered liners in heavy 3-kg clusters and using simultaneous pulsation was 5% higher than with light clusters (1.65 kg) with alternate pulsation. • The milk yield depressions obtained with light clusters were similar in short and long term experiments and increased with the magnitude of the milk yield per milking. • The teat condition scores were not affected by the magnitude of vacuum fluctuations
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