Electrolyte effects on polyacrylic acid-polyvinylpyrrolidone aqueous glycol mixtures for use as de-icing fluids

Rheological and wind tunnels measurements are presented for mixtures of polymers polyacrylic acid [PAA] and polyvinylpyrrolidone [PVP] polymers dispersed in water-1,2 propylene glycol mixture to examine their use as potential aircraft de-icing fluids. PAA solutions which form the basis of de-icing fluids are known to result in undesirable gelation which may lead to undesirable and catastrophic consequences in such applications. In this study, we examine the blending of PVP with PAA blends as alternative de-icing fluid formulations that can reduce the likelihood of forming such irreversible gel deposits. Through adjustment of the electrolyte concentration, the ratio of PAA to PVP as well as the molecular weight of PVP, it is possible to achieve a required viscosity profile to that exhibited by a model de-icing fluid across a range of appropriate temperatures. Wind tunnel tests indicate that the mixtures are capable of meeting the necessary requirements for boundary layer depletion as well as having sufficient capability of retaining a stable layer required during aircraft taxiing

Lossless data compression of monitored power signals using the PLHaar Transform

The quality of AC power is often affected by unpredictable situations like lightning storms and short circuits. Not only does this reduce the efficiency of devices drawing upon mal-formed power signals, but in the highpowered equipment common to industrial installations bad power can cause immense damage to the machines and even pose a danger to nearby human beings. The common solution to this problem is power quality monitors, devices which measure the Voltage and current and issue alerts when the degredation is sufficiently poor to suggest a serious problem. When it rains it pours, unfortunately, and often the problems cascade through the power network, which runs a serious risk of saturating the data network by which the monitoring stations transmit their bulletins. Consequentially, it is preferable to compress the measurements before sending them through the network in a manner not dissimilar from .mp3 audio compression or jpeg image compression. Using recent advances in signal processing, we create a lossless algorithm for the compression of these signals by means of rotating the data through a "space" very different from our typical, Euclidean understanding of the term. Additionally, we show that this space possesses attractive properties which can be utilized to better "fit" transformations into the binary format of computer systems. In fact, it turns out that all typical rotations can be transformed into the odd rotations inherent to this space, and that wavelets, a large class of transformations commonly applied to data compression, corresponds directly to a subset of the ones we introduce

Unifying food web structure and dynamics

A major goal of ecology is to discover how the dynamics and structure of multi-trophic ecological communities are related. It is difficult to understand links between dynamics and structure because mathematical models of the dynamics of systems of realistic complexity have a large number of unmeasured parameters, and whole-community data are limited and typically comprise only a snapshot or time-averaged picture. The resulting 'plague of parameters' means most studies of multi-species population dynamics have been very theoretical. Dynamical models parameterised using physiological allometries suggest a solution to the plague of parameters. These models are a synthesis of allometric scaling and Lotka-Volterra style dynamical models (Yodzis & Innes, 1992): model parameters are computed from empirically-observed inter-specific power-law relationships between physiological rates and body masses. This approach avoids the need to derive species- or population-specific parameters, sacrificing some accuracy for generality and making it possible to investigate the dynamics of complex communities. These models have been used in a large number of theoretical studies that have drawn conclusions on a wide range of topics. Despite their increasing use, this class of dynamical models are rarely tested against empirical data. This PhD examined this modelling approach and some of its assumptions. Outcomes of this work are 1) publication of a new dataset of field metabolic rate data of individual birds and mammals together with an analysis of this data using linear mixed-effects models, leading to a better understanding of one of the model's principal assumptions, 2) an open-source R package for analysing and visualising empirical food-web data, 3) an open-source R package for simulating community dynamics using the model of interest and 4) validation of the model's ability to recreate static patterns seen in empirical community data

SOST Inhibits Prostate Cancer Invasion.

Inhibitors of Wnt signaling have been shown to be involved in prostate cancer (PC) metastasis; however the role of Sclerostin (Sost) has not yet been explored. Here we show that elevated Wnt signaling derived from Sost deficient osteoblasts promotes PC invasion, while rhSOST has an inhibitory effect. In contrast, rhDKK1 promotes PC elongation and filopodia formation, morphological changes characteristic of an invasive phenotype. Furthermore, rhDKK1 was found to activate canonical Wnt signaling in PC3 cells, suggesting that SOST and DKK1 have opposing roles on Wnt signaling in this context. Gene expression analysis of PC3 cells co-cultured with OBs exhibiting varying amounts of Wnt signaling identified CRIM1 as one of the transcripts upregulated under highly invasive conditions. We found CRIM1 overexpression to also promote cell-invasion. These findings suggest that bone-derived Wnt signaling may enhance PC tropism by promoting CRIM1 expression and facilitating cancer cell invasion and adhesion to bone. We concluded that SOST and DKK1 have opposing effects on PC3 cell invasion and that bone-derived Wnt signaling positively contributes to the invasive phenotypes of PC3 cells by activating CRIM1 expression and facilitating PC-OB physical interaction. As such, we investigated the effects of high concentrations of SOST in vivo. We found that PC3-cells overexpressing SOST injected via the tail vein in NSG mice did not readily metastasize, and those injected intrafemorally had significantly reduced osteolysis, suggesting that targeting the molecular bone environment may influence bone metastatic prognosis in clinical settings

A Systematic Review of Physicians' Survival Predictions in Terminally Ill Cancer Patients

Objective: To systematically review the accuracy of physicians’ clinical predictions of survival in terminally ill cancer patients. Data sources: Cochrane Library, Medline (1996-2000), Embase, Current Contents, and Cancerlit databases as well as hand searching. Study selection: Studies were included if a physician’s temporal clinical prediction of survival (CPS) and the actual survival (AS) for terminally ill cancer patients were available for statistical analysis. Study quality was assessed by using a critical appraisal tool produced by the local health authority. Data synthesis: Raw data were pooled and analysed with regression and other multivariate techniques. Results: 17 published studies were identified; 12 met the inclusion criteria, and 8 were evaluable, providing 1563 individual prediction-survival dyads. CPS was generally overoptimistic (median CPS 42 days, median AS 29 days); it was correct to within one week in 25% of cases and overestimated survival by at least four weeks in 27%. The longer the CPS the greater the variability in AS. Although agreement between CPS and AS was poor (weighted k 0.36), the two were highly significantly associated after log transformation (Spearman rank correlation 0.60, P < 0.001). Consideration of performance status, symptoms, and use of steroids improved the accuracy of the CPS, although the additional value was small. Heterogeneity of the studies’ results precluded a comprehensive meta-analysis. Conclusions: Although clinicians consistently overestimate survival, their predictions are highly correlated with actual survival; the predictions have discriminatory ability even if they are miscalibrated. Clinicians caring for patients with terminal cancer need to be aware of their tendency to overestimate survival, as it may affect patients’ prospects for achieving a good death. Accurate prognostication models incorporating clinical prediction of survival are needed.Sociolog

Maintaining muscle mass during extended disuse: aestivating frogs as a model species

Prolonged muscle disuse in vertebrates can lead to a pathological change resulting in muscle wasting and a loss of muscle strength. In this paper, we review muscle disuse atrophy in the vertebrates and examine the factors that influence the magnitude of the atrophic response during extended periods of inactivity, both artificially imposed (e.g. limb immobilisation) and naturally occurring, such as the quiescence associated with dormancy (e.g. hibernation and aestivation). The severity of muscle atrophy is positively correlated with mass-specific metabolic rate, and the metabolic depression that occurs during dormancy would appear to have a protective role, reducing or preventing muscle atrophy despite periods of inactivity lasting 6-9 months. In the light of these findings, the role of reactive oxygen species and antioxidants during muscle disuse is emphasised

Appendix 2. Guide for Running AgMIP Climate Scenario Generation Tools with R in Windows, Version 2.3

This Guide explains how to create climate series and climate change scenarios by using the AgMip Climate team's methodology as outlined in the AgMIP Guide for Regional Assessment: Handbook of Methods and Procedures. It details how to: install R and the required packages to run the AgMIP Climate Scenario Generation scripts, and create climate scenarios from CMIP5 GCMs using a 30-year baseline daily weather dataset. The Guide also outlines a workflow that can be modified for application to your own climate data

Assessing the medium-term impact of permeable pond covers on pond performance and odour management

Assessment of the efficacy of permeable pond covers over a three-year period has confirmed that they are a cost-effective odour management tool. They have an anticipated life expectancy of at least ten years. Investigation of emissions of volatile chemicals and gases, as well as pond chemistry, has not provided any justification to avoid recommendation of this relatively low cost technology. Regulatory agencies are now in a position to accept this technology as one that has been adequately investigated, and as a consequence of which, predictable performance may be anticipated. Adoption of this technology by the pig industry as an odour control tool should be limited only by site-specific circumstances and the costs and benefits of alternate technologies