Confidence in assessing the effectiveness of bath treatments for the control of sea lice on Norwegian salmon farms

The salmon louse Lepeophtheirus salmonis is the most important ectoparasite of farmed salmonids in the Northern hemisphere, having a major economic and ecological impact on the sustainability of this sector of the aquaculture industry. To a large extent, control of L. salmonis relies on the use of topical delousing chemical treatments in the form of baths. Improvements in methods for the administration and assessment of bathtreatments have not kept pace with the rapid modernization and intensification of the salmon industry. Bathtreatments present technical and biological challenges, including best practice methods for the estimation of the effect of licetreatment interventions. In this communication, we compare and contrast methods to calculate and interpret treatmenteffectiveness at pen and site level. The methods are illustrated for the calculation of the percentage reduction in mean abundance of mobile lice with a measure of confidence. Six different methods for the calculation of confidence intervals across different probability levels were compared. We found the quasi-Poisson method with a 90% confidence interval to be informative and robust for the measurement of bathtreatment performance

The Intracluster Medium in z > 1 Galaxy Clusters

The Chandra X-ray Observatory was used to obtain a 190 ks image of three high redshift galaxy clusters in one observation. The results of our analysis of these data are reported for the two z > 1 clusters in this Lynx field, including the most distant known X-ray selected cluster. Spatially-extended X-ray emission was detected from both these clusters, indicating the presence of hot gas in their intracluster media. A fit to the X-ray spectrum of RX J0849+4452, at z=1.26, yields a temperature of kT = 5.8^{+2.8}_{-1.7} keV. Using this temperature and the assumption of an isothermal sphere, the total mass of RX J0849+4452 is found to be 4.0^{+2.4}_{-1.9} X 10^{14} h_{65}^{-1} M_{\sun} within r = 1 h_{65}^{-1} Mpc. The T_x for RX J0849+4452 approximately agrees with the expectation based on its L_{bol} = 3.3^{+0.9}_{-0.5} X 10^{44}$erg s$^{-1} according to the low redshift L_x - T_x relation. The very different distributions of X-ray emitting gas and of the red member galaxies in the two z > 1 clusters, in contrast to the similarity of the optical/IR colors of those galaxies, suggests that the early-type galaxies mostly formed before their host clusters.Comment: 4 pages in emulateapj style plus 2 color jpegs for Figure 3. Accepted by The Astrophysical Journa

Role of choline deficiency in the fatty liver phenotype of mice fed a low protein, very low carbohydrate ketogenic diet

Though widely employed for clinical intervention in obesity, metabolic syndrome, seizure disorders and other neurodegenerative diseases, the mechanisms through which low carbohydrate ketogenic diets exert their ameliorative effects still remain to be elucidated. Rodent models have been used to identify the metabolic and physiologic alterations provoked by ketogenic diets. A commonly used rodent ketogenic diet (Bio-Serv F3666) that is very high in fat (~94% kcal), very low in carbohydrate (~1% kcal), low in protein (~5% kcal), and choline restricted (~300 mg/kg) provokes robust ketosis and weight loss in mice, but through unknown mechanisms, also causes significant hepatic steatosis, inflammation, and cellular injury. To understand the independent and synergistic roles of protein restriction and choline deficiency on the pleiotropic effects of rodent ketogenic diets, we studied four custom diets that differ only in protein (5% kcal vs. 10% kcal) and choline contents (300 mg/kg vs. 5 g/kg). C57BL/6J mice maintained on the two 5% kcal protein diets induced the most significant ketoses, which was only partially diminished by choline replacement. Choline restriction in the setting of 10% kcal protein also caused moderate ketosis and hepatic fat accumulation, which were again attenuated when choline was replete. Key effects of the 5% kcal protein diet - weight loss, hepatic fat accumulation, and mitochondrial ultrastructural disarray and bioenergetic dysfunction - were mitigated by choline repletion. These studies indicate that synergistic effects of protein restriction and choline deficiency influence integrated metabolism and hepatic pathology in mice when nutritional fat content is very high, and support the consideration of dietary choline content in ketogenic diet studies in rodents to limit hepatic mitochondrial dysfunction and fat accumulation

“It ain’t (just) what you do, it’s (also) the way that you do it”: The role of Procedural Justice in the Implementation of Anti-social Behaviour Interventions with Young People

This paper provides an analysis of the introduction and implementation of hybrid powers to regulate anti-social behaviour, during a period of regulatory ‘hyperactivity’ in the UK. It explores the role of procedural justice by drawing on findings from a study conducted in England which investigated the implementation practices and experiences of young people and parents. These are considered against seven characteristics of procedural justice: voice; voluntariness; respectful treatment; parsimony; accuracy of information; fairness; and neutrality. The paper analyses the manner in which principles of voluntary cooperation can be corrupted by threats of punitive sanctions. It questions the extent to which the use of such hybrid orders fosters perceptions of legitimacy and supports the capacity of young people to avoid criminalisation

Damned if they do, damned if they don't: negotiating the tricky context of anti-social behaviour and keeping safe in disadvantaged urban neighbourhoods

Young people's relationship with anti-social behaviour (ASB) is complicated. While their behaviours are often stereotyped as anti-social (e.g. ‘hanging about’), they also experience ASB in their neighbourhood. In this study, we explore young people's own perspectives on ASB, comparing results from ‘go-along’ interviews and focus groups conducted in disadvantaged neighbourhoods in Glasgow, Scotland. This article discusses how young people's everyday experience of ASB was contextualised by social factors such as cultural stereotyping of marginalised groups, poor social connectivity and spatial marginalisation within their neighbourhood. Furthermore, we found that these social factors were mutually reinforcing and interacted in a way that appeared to leave young people in a ‘no-win’ situation regarding their association with ASB. Participation in ASB and attempts to avoid such involvement were seen to involve negative consequences: participation could entail violence and spatial restrictions linked to territoriality, but avoidance could lead to being ostracised from their peer group. Regardless of involvement, young people felt that adults stereotyped them as anti-social. Our findings therefore provide support for policies and interventions aimed at reducing ASB (perpetrated by residents of all ages); in part by better ensuring that young people have a clear incentive for avoiding such behaviours

An X-ray Selected Galaxy Cluster at z=1.26

We report the discovery of an X-ray luminous galaxy cluster at z=1.26. RXJ0848.9+4452 was selected as an X-ray cluster candidate in the ROSAT Deep Cluster Survey, on the basis of its spatial extent. Deep optical and near-IR imaging have revealed a galaxy overdensity around the peak of the X-ray emission, with a significant excess of red objects with J-K colors typical of elliptical galaxies at z>1. Spectroscopic observations at the Keck II telescope have secured 6 galaxy redshifts in the range 1.257=1.261), within a 35 arcsec radius around the peak X-ray emission. This system lies only 4.2 arcmin away (5.0 h^{-1}_{50} comoving Mpc, q_0=0.5) from the galaxy cluster ClG J0848+4453, which was identified by Stanford et al. (1997) at z=1.273 in a near-IR field galaxy survey, and is also known to be X-ray luminous. Assuming that the X-ray emission is entirely due to hot intra-cluster gas, both these systems have similar rest frame luminosities L_x ~=1x10^{44} ergs/s (0.5-2.0 keV band). In combination with our spectrophotometric data for the entire 30 arcmin^2 field, this suggests the presence of a superstructure, consisting of two collapsed, possibly virialized clusters, the first detected to date at z>1.Comment: To appear in The Astronomical Journal, 24 pages, 8 figures, 1 color jpg plate (fig.7), see http://www.eso.org/~prosati/lynx/plate_fig7.jp

Modeling parasite dynamics on farmed salmon for precautionary conservation management of wild salmon

Conservation management of wild fish may include fish health management in sympatric populations of domesticated fish in aquaculture. We developed a mathematical model for the population dynamics of parasitic sea lice (Lepeophtheirus salmonis) on domesticated populations of Atlantic salmon (Salmo salar) in the Broughton Archipelago region of British Columbia. The model was fit to a seven-year dataset of monthly sea louse counts on farms in the area to estimate population growth rates in relation to abiotic factors (temperature and salinity), local host density (measured as cohort surface area), and the use of a parasiticide, emamectin benzoate, on farms. We then used the model to evaluate management scenarios in relation to policy guidelines that seek to keep motile louse abundance below an average three per farmed salmon during the March-June juvenile wild Pacific salmon (Oncorhynchus spp.) migration. Abiotic factors mediated the duration of effectiveness of parasiticide treatments, and results suggest treatment of farmed salmon conducted in January or early February minimized average louse abundance per farmed salmon during the juvenile wild salmon migration. Adapting the management of parasites on farmed salmon according to migrations of wild salmon may therefore provide a precautionary approach to conserving wild salmon populations in salmon farming regions