Thermodynamically consistent description of the hydrodynamics of free surfaces covered by insoluble surfactants of high concentration

In this paper we propose several models that describe the dynamics of liquid films which are covered by a high concentration layer of insoluble surfactant. First, we briefly review the 'classical' hydrodynamic form of the coupled evolution equations for the film height and surfactant concentration that are well established for small concentrations. Then we re-formulate the basic model as a gradient dynamics based on an underlying free energy functional that accounts for wettability and capillarity. Based on this re-formulation in the framework of nonequilibrium thermodynamics, we propose extensions of the basic hydrodynamic model that account for (i) nonlinear equations of state, (ii) surfactant-dependent wettability, (iii) surfactant phase transitions, and (iv) substrate-mediated condensation. In passing, we discuss important differences to most of the models found in the literature.Comment: 31 pages, 2 figure

Density functional approach for inhomogeneous star polymers

We propose microscopic density functional theory for inhomogeneous star polymers. Our approach is based on fundamental measure theory for hard spheres, and on Wertheim's first- and second-order perturbation theory for the interparticle connectivity. For simplicity we consider a model in which all the arms are of the same length, but our approach can be easily extended to the case of stars with arms of arbitrary lengths.Comment: 4 pages, 3 figures, submitte

Revision of basal macropodids from the Riversleigh World Heritage Area with descriptions of new material of Ganguroo bilamina Cooke, 1997 and a new species

The relationship of basal macropodids (Marsupialia: Macropodoidea) from the Oligo-Miocene of Australia have been unclear. Here, we describe a new species from the Bitesantennary Site within the Riversleigh's World Heritage Area (WHA), Ganguroo bites n. sp., new cranial and dental material of G. bilamina, and reassess material previously described as Bulungamaya delicata and 'Nowidgee matrix'. We performed a metric analysis of dental measurements on species of Thylogale which we then used, in combination with morphological features, to determine species boundaries in the fossils. We also performed a phylogenetic analysis to clarify the relationships of basal macropodid species within Macropodoidea. Our results support the distinction of G. bilamina, G. bites and B. delicata, but 'Nowidgee matrix' appears to be a synonym of B. delicata. The results of our phylogenetic analysis are inconclusive, but dental and cranial features suggest a close affinity between G. bilamina and macropodids. Finally, we revise the current understanding of basal macropodid diversity in Oligocene and Miocene sites at Riversleigh WHA

Sustainability of water resources management in the Indus Basin under changing climatic and socio economic conditions

Pakistan is highly dependent on water resources originating in the mountain sources of the upper Indus for irrigated agriculture which is the mainstay of its economy. Hence any change in available resources through climate change or socio-economic factors could have a serious impact on food security and the environment. In terms of both ratio of withdrawals to runoff and per-capita water availability, Pakistan's water resources are already highly stressed and will become increasingly so with projected population changes. Potential changes to supply through declining reservoir storage, the impact of waterlogging and salinity or over-abstraction of groundwater, or reallocations for environmental remediation of the Indus Delta or to meet domestic demands, will reduce water availability for irrigation. <br><br> The impact of climate change on resources in the Upper Indus is considered in terms of three hydrological regimes – a nival regime dependent on melting of winter snow, a glacial regime, and a rainfall regime dependent on concurrent rainfall. On the basis of historic trends in climate, most notably the decline in summer temperatures, there is no strong evidence in favour of marked reductions in water resources from any of the three regimes. Evidence for changes in trans-Himalayan glacier mass balance is mixed. Sustainability of water resources appears more threatened by socio-economic changes than by climatic trends. Nevertheless, analysis and the understanding of the linkage of climate, glaciology and runoff is still far from complete; recent past climate experience may not provide a reliable guide to the future

Natural flood management: does age of forest influence flood mitigation?

Forestry has the potential to alleviate flooding by delaying the downstream passage of flood flows, reducing the volume of runoff through interception (Calder et al. 2003) and promoting rainfall infiltration into the soil (Forest Research, 2010). However, it is difficult to predict how much a forest needs to grow, before there is any significant effect on soil properties to increase the capacity to 1) store water, 2) increase soil infiltration, 3) slow water and reduce water flow connectivity to rivers. The structural coupling between plant roots and soil environment determines flow paths through the soil, where root growth and die-back influences soil hydraulic properties, increasing macropore distribution (Bengough, 2012) and soil permeability. We test the hypothesis: as the forest grows soil permeability below forests will increase, due to increasing macropore structure

PROCEE: a PROstate Cancer Evaluation and Education serious game for African Caribbean men

Purpose – Prostate cancer is the most common cancer diagnosed in men in the UK. Black men are in a higher prostate cancer risk group possibly due to inherent genetic factors. The purpose of this paper is to introduce PROstate Cancer Evaluation and Education (PROCEE), an innovative serious game aimed at providing prostate cancer information and risk evaluation to black African-Caribbean men. Design/methodology/approach – PROCEE has been carefully co-designed with prostate cancer experts, prostate cancer patients and members of the black African-Caribbean community in order to ensure that it meets the real needs and expectations of the target audience. Findings – During the co-design process, the users defined an easy to use and entertaining game which can effectively raise awareness, inform users about prostate cancer and their risk, and encourage symptomatic men to seek medical attention in a timely manner. Originality/value – During focus group evaluations, users embraced the game and emphasised that it can potentially have a positive impact on changing user behaviour among high risk men who are experiencing symptoms and who are reluctant to visit their doctor

Development of soil hydraulic properties below grassland, ancient forest and plantation forests

Woodlands in particular have the potential to alleviate flooding by delaying the downstream passage of flood flows, reducing the volume of runoff through interception (Calder et al. 2003) and promoting rainfall infiltration into the soil (Thomas & Nisbet, 2006). The natural processes which occur below ground to enable a change in hydraulic pathways and storage are complex and are dependent not only on geology, but also on landuse. We focus this study on below-ground changes that influence soil water characteristics, such as soil hydraulic conductivity, soil water retention and soil structure, which are all important in understanding how the planting of trees can mitigate localised flooding

Lameness in UK dairy cows: a review of the current status

Lameness in dairy cattle has been reported as a concern for welfare and economic reasons for over 20 years. This concern has been expressed from across the industry and has prompted the launch of a number of initiatives to address the problem. This article reviews the current status of lameness in dairy cows in the UK, outlines the current understanding of the condition and its impacts on welfare and productivity, and highlights areas where evidence is still lacking

Assessing doctors' competencies using multisource feedback: validating a Japanese version of the Sheffield Peer Review Assessment Tool (SPRAT).

OBJECTIVE: To assess the validity and reliability of the Sheffield Peer Review Assessment Tool (SPRAT) Japanese version for evaluating doctors' competencies using multisource feedback. METHODS: SPRAT, originally developed in the UK, was translated and validated in three phases: (1) an existing Japanese version of SPRAT was back-translated into English; (2) two expert panel meetings were held to develop and assure content validity in a Japanese setting; (3) the newly devised Japanese SPRAT instrument was tested by a multisource feedback survey, validity was tested using principal component factor analysis, and reliability was assessed using generalisability and decision studies based on generalisability theory. RESULTS: 86 doctors who had been practising for between 2 and 33 years participated as assessees and were evaluated with the SPRAT tool. First, the doctors identified 1019 potential assessors who were each sent SPRAT forms (response rate, 81%). The mean number of assessors per doctor was 9.7 (SD=2.5). The decision study showed that 95% CIs of ± 0.5 were achieved with only 5 assessors. 85 of the 86 doctors achieved scores that could be placed with 95% CI above the 4 expected standard. Doctors received lower scores from more senior assessors (p<0.001) and higher scores from those they had known longer (p<0.001). Scores also varied with the job role (p<0.05). CONCLUSIONS: Following translation and content validation, the Japanese instrument behaved similarly to the UK tool. Assessor selection remains a primary concern, as the assessment scores are affected by the seniority of the assessor, the length of the assessor-assessee working relationship, and the assessor's job role. Users of the SPRAT tool need to be aware of these limitations when administering the instrument

Fluid-fluid demixing transitions in colloid--polyelectrolyte star mixtures

We derive effective interaction potentials between hard, spherical colloidal particles and star-branched polyelectrolytes of various functionalities and smaller size than the colloids. The effective interactions are based on a Derjaguin-like approximation, which is based on previously derived potentials acting between polyelectrolyte stars and planar walls. On the basis of these interactions we subsequently calculate the demixing binodals of the binary colloid--polyelectrolyte star mixture, employing standard tools from liquid-state theory. We find that the mixture is indeed unstable at moderately high overall concentrations. The system becomes more unstable with respect to demixing as the star functionality and the size ratio grow.Comment: 24 pages, 9 figures, submitted to Journal of Physics: Condensed Matte