Operational trials of different propriety lamella and BAF systems

Halcrow Scotland were appointed by Grampian Regional Council (now North of Scotland Water Authority) in April 1993 to carry out the Aberdeen Wastewater Treatment Feasibility Study. The study started with a verification of the flows and polluting loads generated within the catchment followed by a review of the treatment technologies available. The purpose of examining the available technologies was to ascertain the land areas required. Different technologies had different land requirements, and it was important to evaluate this for the site selection stage. Inevitably, conventional activated sludge treatment processes required the greater land take, but it was the only proven technology as far as the client was concerned. Other treatment processes, loosely termed "small footprint", could be accommodated within a much smaller area. The most promising of these processes was Biological Aerated Flooded Filters (BAFF), but at that time there were very few plants operating in the UK and none in Scotland. Halcrow recommended that the client establish pilot plant trials of the BAFF process. For minimal land take lamella plate separators would be required in the primary treatment stage and it was decided to include this compact settlement process (with or without chemical assistance) in the pilot plant trials

What are elections for? conferring the median mandate

Democracy is often described as a system in which a majority of electors choose one out of a number of competing parties to form a government and carry out its programme. Unfortunately, spontaneous majorities rarely form in support of one party. We generalize from a 'government' to a 'median' mandate, in which the median elector chooses the pivotal party in parliament, which then translates his or her preferences into public policy. To check this we investigate how accurately parliaments and governments represent the left-right position of the median voter in each of twenty parliamentary democracies. Distortions depend on the type of electoral arrangement, being relatively smaller under proportional representation than under single-member districts. Distortions do not equate to biased representation, however. Once we consider how distortions at one step or one time are compensated by distortions in the opposite direction at another, overall representation of the median voter position is reasonably accurate

Quantifying the value of ecosystem services: a case study of honeybee pollination in the UK

There is concern that insect pollinators, such as honey bees, are currently declining in abundance, and are under serious threat from environmental changes such as habitat loss and climate change; the use of pesticides in intensive agriculture, and emerging diseases. This paper aims to evaluate how much public support there would be in preventing further decline to maintain the current number of bee colonies in the UK. The contingent valuation method (CVM) was used to obtain the willingness to pay (WTP) for a theoretical pollinator protection policy. Respondents were asked whether they would be WTP to support such a policy and how much would they pay? Results show that the mean WTP to support the bee protection policy was £1.37/week/household. Based on there being 24.9 million households in the UK, this is equivalent to £1.77 billion per year. This total value can show the importance of maintaining the overall pollination service to policy makers. We compare this total with estimates obtained using a simple market valuation of pollination for the UK

Modelling the spread of American foulbrood in honeybees

We investigate the spread of American foulbrood (AFB), a disease caused by the bacterium Paenibacillus larvae, that affects bees and can be extremely damaging to beehives. Our dataset comes from an inspection period carried out during an AFB epidemic of honeybee colonies on the island of Jersey during the summer of 2010. The data include the number of hives of honeybees, location and owner of honeybee apiaries across the island. We use a spatial SIR model with an underlying owner network to simulate the epidemic and characterize the epidemic using a Markov chain Monte Carlo (MCMC) scheme to determine model parameters and infection times (including undetected ‘occult’ infections). Likely methods of infection spread can be inferred from the analysis, with both distance- and owner-based transmissions being found to contribute to the spread of AFB. The results of the MCMC are corroborated by simulating the epidemic using a stochastic SIR model, resulting in aggregate levels of infection that are comparable to the data. We use this stochastic SIR model to simulate the impact of different control strategies on controlling the epidemic. It is found that earlier inspections result in smaller epidemics and a higher likelihood of AFB extinction

Maternal parity and its effect on adipose tissue deposition and endocrine sensitivity in the postnatal sheep

Maternal parity influences size at birth, postnatal growth and body composition with firstborn infants being more likely to be smaller with increased fat mass, suggesting that adiposity is set in early life. The precise effect of parity on fat mass and its endocrine sensitivity remains unclear and was, therefore, investigated in the present study. We utilised an established sheep model in which perirenal–abdominal fat mass (the major fat depot in the neonatal sheep) increases ∼10-fold over the first month of life and focussed on the impact of parity on glucocorticoid sensitivity and adipokine expression in the adipocyte. Twin-bearing sheep of similar body weight and adiposity that consumed identical diets were utilised, and maternal blood samples were taken at 130 days of gestation. One offspring from each twin pair was sampled at 1 day of age, coincident with the time of maximal recruitment of uncoupling protein 1 (UCP1), whilst its sibling was sampled at 1 month, when UCP1 had disappeared. Plasma leptin was lower in nulliparous mothers than in multiparous mothers, and offspring of nulliparous mothers possessed more adipose tissue with increased mRNA abundance of leptin, glucocorticoid receptor and UCP2, adaptations that persisted up to 1 month of age when gene expression for interleukin-6 and adiponectin was also raised. The increase in fat mass associated with firstborn status is therefore accompanied by a resetting of the leptin and glucocorticoid axis within the adipocyte. Our findings emphasise the importance of parity in determining adipose tissue development and that firstborn offspring have an increased capacity for adipogenesis which may be critical in determining later adiposity

Downs, Stokes and the Dynamics of Electoral Choice

A six-wave 2005–09 national panel survey conducted in conjunction with the British Election Study provided data for an investigation of sources of stability and change in voters’ party preferences. The authors test competing spatial and valence theories of party choice and investigate the hypothesis that spatial calculations provide cues for making valence judgements. Analyses reveal that valence mechanisms – heuristics based on party leader images, party performance evaluations and mutable partisan attachments – outperform a spatial model in terms of strength of direct effects on party choice. However, spatial effects still have sizeable indirect effects on the vote via their influence on valence judgements. The results of exogeneity tests bolster claims about the flow of influence from spatial calculations to valence judgments to electoral choice.</jats:p

Analyzing Ideological Communities in Congressional Voting Networks

We here study the behavior of political party members aiming at identifying how ideological communities are created and evolve over time in diverse (fragmented and non-fragmented) party systems. Using public voting data of both Brazil and the US, we propose a methodology to identify and characterize ideological communities, their member polarization, and how such communities evolve over time, covering a 15-year period. Our results reveal very distinct patterns across the two case studies, in terms of both structural and dynamic properties

Fast DNA translocation through a solid-state nanopore

We report translocation experiments on double-strand DNA through a silicon oxide nanopore. Samples containing DNA fragments with seven different lengths between 2000 to 96000 basepairs have been electrophoretically driven through a 10 nm pore. We find a power-law scaling of the translocation time versus length, with an exponent of 1.26 $\pm$ 0.07. This behavior is qualitatively different from the linear behavior observed in similar experiments performed with protein pores. We address the observed nonlinear scaling in a theoretical model that describes experiments where hydrodynamic drag on the section of the polymer outside the pore is the dominant force counteracting the driving. We show that this is the case in our experiments and derive a power-law scaling with an exponent of 1.18, in excellent agreement with our data.Comment: 5 pages, 2 figures. Submitted to PR