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Populations of Afro-Palearctic migrant birds have shown severe declines in recent decades. To identify the causes of these declines, accurate measures of both demographic rates (seasonal productivity, apparent survival, immigration) and environmental parameters will allow conservation and research actions to be targeted effectively. We used detailed observations of marked breeding birds from a ‘stronghold’ population of whinchats Saxicola rubetra in England (stable against the declining European trend) to reveal both on-site and external mechanisms that contribute to population change. From field data, a population model was developed based on demographic rates from 2011 to 2014. Observed population trends were compared to the predicted population trends to assess model-accuracy and the influence of outside factors, such as immigration. The sensitivity of the projected population growth rate to relative change in each demographic rate was also explored. Against expectations of high productivity, we identified low seasonal breeding success due to nocturnal predation and low apparent first-year survival, which led to a projected population growth rate (λ) of 0.818, indicating a declining trend. However, this trend was not reflected in the census counts, suggesting that high immigration was probably responsible for buffering against this decline. Elasticity analysis indicated λ was most sensitive to changes in adult survival but with covariance between demographic rates accounted for, most temporal variation in λ was due to variation in productivity. Our study demonstrates that high quality breeding habitat can buffer against population decline but high immigration and low productivity will expose even such stronghold populations to potential decline or abandonment if either factor is unsustainable. First-year survival also appeared low, however this result is potentially confounded by high natal dispersal. First-year survival and/or dispersal remains a significant knowledge gap that potentially undermines local solutions aimed at counteracting low productivity.

Aims: The treatment of prostate cancer has evolved markedly over the last 40 years, including radiotherapy, notably with escalated dose and targeting. However, the optimal treatment for localised disease has not been established in comparative randomised trials. The aim of this article is to describe the history ofprostate radiotherapy trials, including their quality assurance processes, and to compare these with the ProtecT trial.Materials and methods: The UK ProtecT randomised trial compares external beam conformal radiotherapy, surgery and active monitoring for clinically localized prostate cancer and will report on the primary outcome (disease-specific mortality) in 2016 following recruitment between 1999 and 2009. The embedded quality assurance programme consists of on-site machine dosimetry at the nine trial centres, a retrospective review of outlining and adherence to dose constraints based on the trial protocol in 54 participants (randomly selected, around 10% of the total randomised to radiotherapy, n ¼ 545). These quality assurance processes and results were compared with prostate radiotherapy trials of a comparable era.Results: There has been an increasingly sophisticated quality assurance programme in UK prostate radiotherapy trials over the last 15 years, reflecting dose escalation and treatment complexity. In ProtecT, machine dosimetry results were comparable between trial centres and with the UK RT01 trial. The outliningreview showed that most deviations were clinically acceptable, although three (1.4%) may have been of clinical significance and were related to outlining of theprostate. Seminal vesicle outlining varied, possibly due to several prostate trials running concurrently with different protocols. Adherence to dose constraints inProtecT was considered acceptable, with 80% of randomised participants having two or less deviations and planning target volume coverage was excellent.Conclusion: The ProtecT trial quality assurance results were satisfactory and comparable with trials of its era. Future trials should aim to standardise treatment protocols and quality assurance programmes where possible to reduce complexities for centres involved in multiple trials. 2016 Published by Elsevier Ltd on behalf of The Royal College of Radiologists.

Ice pigging is a process used by many industries for pipe cleaning and product recovery. Ice slurries, used to form an ice pig, are generated using an aqueous solution of water and a freezing point depressant, typically salt (NaCl) at 5% salinity. The ‘thickness’ of an ice slurry is key to the ice pig's performance, and this paper investigates a new non-invasive method of ice fraction measurement. Electromagnetic (EM) waves, with a frequency of 2.5 GHz, are absorbed rapidly by water molecules, but pass through ice with little drop in intensity, due to key differences in the materials' atomic structures. This phenomenon is exploited, and results show ice fraction can be approximated to within ±1.2% using a VNA spectrum analyser, then mathematical manipulation and analysis. This rivals the error in calorimetry, ±1.3%, which currently seen as the ‘gold standard’ in ice fraction measurement across the industry.

Significant improvements in coefficient of performance (COP) can be made when the evaporating temperature of a vapour compression cycle is raised. Producing the ice slurries used in cooling applications and ice pigging by crushing blocks of ice made from pure water and mixing the particles with a solution of freezing point depressant (FPD) later enables higher evaporator temperatures than if the solution itself is frozen in a scraped surface ice maker. Predictions of the possible improvements to COP can be made in CoolPack, a refrigeration cycle simulation program, over a range of evaporator temperatures. A series of experiments designed to verify these predictions were carried out where the operating conditions of a scraped surface ice maker were altered by retrofitting compressor speed control to a scraped surface ice maker. Following verification of the CoolPack results, further experiments were conducted that evaluated the energy required for two stage comminution of large ice blocks into fine particles. Two theoretical slurry production systems were then compared: mixing crushed ice with an FPD solution and a scraped surface ice maker with FPD solution feedstock. Although energy conservation was shown with comminution the proposed method introduces a number of challenges that require careful consideration.

The paper examines the transient melting rates of ice slurries being pumped through pipes whose walls are initially warmer than the freezing temperature of the slurry. The application for this work is the new innovative pipe cleaning method known as ice pigging. Ice pigging consists of introducing a length of ice slurry consisting of small ice crystals in a fluid matrix of water and a freezing point depressant into a pipe. The ice slurry forms a semi-solid plug whose temperature is at the freezing temperature of ice at the prevailing operating conditions. The plug cools the pipe walls, which in turn results in some phase change within the slurry. The plug is propelled along the pipe by a pressurised fluid introduced behind the plug. This results in the pipe walls being exposed to large time-varying temperature changes, with the front of the plug receiving the greatest heat flux. The purpose of undertaking ice pigging is to clean the pipe walls with the high shear at between the walls and the semi-solid slurry. Analytical transient conduction theory is adopted to estimate the energy removed from the pipe wall as a result of the passing ice pig. This is used to develop equations predicting the amount of phase change occurring in the pig and hence estimate the distance it can travel before it has melted. The resultant model enables ice pig users to estimate how much ice slurry is required to undertake successfully a specific ice pigging task.

Producing ice slurries by crushing blocks of ice and mixing them with an aqueous solution of freezing point depressant can significantly increase the coefficient of system performance, decrease production time and eliminate the negative effects of time behaviour associated with storing fine particle ice slurries. As ice is mixed with an aqueous solution, it melts or freezes, diluting or concentrating the liquid phase. Its resultant properties can be estimated from an enthalpy balance. Using the phase diagram of the NaCl + H 2 O system and published heat capacity curves for ice and brine, a model is constructed that predicts resultant ice slurry properties following mixing. Model predictions are confirmed by experiments where a number of ice, water and salt mixtures are produced whilst their properties are monitored. Finally, it is shown how this method can be used to give optimum salt gritting loads for the deicing of roads.

Water-supply companies monitor the state of their pipe networks and ensure that the pipes are clean and free of inert loose deposits by flushing and pigging. Flushing involves forcing high speed water through the pipes so as to carry away particulates, pigging consists of forcing an object (the pig) through the pipe so as to push or wipe away the loose material. Both systems have drawbacks; the first tends to use very large volumes of water, and it may be impossible to get the required velocities in large-diameter pipes. The second requires purpose built launch and receive stations and may run the risk of damaging the pipe walls. This paper presents an innovative alternative to water flushing or conventional pigging for the potable-water-supply industry. This alternative uses a phase change material (ice—water slurry), which can be introduced into and removed from existing pipe networks with minimal alterations. The underlying concept is that when an ice slurry is propelled through pipes at modest speeds, the wall shear is two to four orders of magnitude higher than that which would have been achieved had water (only) been travelling in the pipe at the same speed. Thus, even with relatively low speeds, the ‘ice pig’ is able to achieve efficient cleaning and removal of loose materials. This technology has the advantage that the ice pig changes its shape to fit the containing topology, hence it is able to navigate bends, contraction/expansions and partly open vales, while cleaning the containment walls and transporting particulates. Lastly, the ice pig is guaranteed never to get stuck, as it will simply melt away, if left for sufficient time. The paper presents laboratory experimental data, qualitatively demonstrating the capability of the technique and quantitative data enabling engineers to scale and size the ice pig for full scale trials. Finally, preliminary work from full scale trails on live water trunk mains is briefly presented and discussed.