Dietary pesticide chlorpyrifos-methyl affects arachidonic acid metabolism including phospholipid remodeling in Atlantic salmon (Salmo salar L.)

The pesticide chlorpyrifos-methyl (CLP-m) has been identified in plant ingredients intended for aquaculture feed production. To investigate systemic effects of CLP-m with emphasis on lipid metabolism, post-smolt Atlantic salmon were fed in duplicate (n = 2) either diets with no CLP-m (Control) or CLP-m at different concentrations (0.1, 1.0 or 8.0 mg kg(-1)) for a total of 67 days (Low, Medium, High). Fish in all groups almost doubled their weight during the feeding trial from 262 +/- 26 g (mean +/- SD) to 465 +/- 64 g (overall mean), with no significant effects on any growth parameters. There was a significant dose-dependent inhibition of plasma cholinesterase activity (BuChE) after 67 days. The CLP-m biotransformation metabolite, TCP was detected in liver and bile, with low levels of the parent compound in the organs. Spleen somatic index decreased significantly with increasing dietary CLP-m intake. Hematocrit (%) decreased linearly with increasing dietary exposure to CLP-m after 30 days of exposure, but this decrease was less at 67 days of exposure. A significantly reduced content of arachidonic acid (ARA 20:4n - 6), accompanied by a significantly increased content of the saturated fatty acid, palmitic acid (PA 16:0), was observed in liver phospholipids (PLs) with increasing dietary content of CLP-m. Major effects were seen on the PL classes in liver which showed a significantly decreased absolute content, possibly indicating inhibition of PL remodeling pathways or other membrane perturbation effects from CLP-m exposure. In conclusion, this study shows that the pesticide CLP-m is a relatively potent toxicant in Atlantic salmon, especially affecting liver PLs and ARA metabolism

Something ‘Old’, Something ‘New’? The UK Space of Political Attitudes After the Brexit Referendum

This study focuses on the political attitudes of UK citizens in the aftermath of the ‘Brexit’ vote. It has been argued that differences within electorates across Europe are found in disputes over taxes, redistribution of wealth and social welfare, as much as in divergent ideas on how to deal with globalisation, migration, and climate change. This article uses the 2016–2017 round of the European Social Survey (N = 1959) to shed light on two important issues in regard to the relationship between ‘old’ and ‘new’ politics. By using multiple correspondence analysis, we first consider the structure, or dimensionality, of the space of political attitudes in contemporary UK society. Contrary to a prevailing discourse that forwards the argument that postmaterial values constitute an altogether separate political dimension in late modernity, we observe that such values collapse into traditional left/right standpoints. Second, we discuss the connection between class (economic capital, cultural capital, and occupational class) and position-takings in the space of political attitudes. We show that class retains a limited effect on political position-takings, where educational capital plays the most important role. The divisions between the politically interested–uninterested, old–young, men–women, and rural–urban are more clearly demarcated than differences between people of different social class positions. Furthermore, polarisation is most prevalent between a highly opinionated, relatively resourceful, small minority of the population

Transition probabilities for general birth-death processes with applications in ecology, genetics, and evolution

A birth-death process is a continuous-time Markov chain that counts the number of particles in a system over time. In the general process with $n$ current particles, a new particle is born with instantaneous rate $\lambda_n$ and a particle dies with instantaneous rate $\mu_n$. Currently no robust and efficient method exists to evaluate the finite-time transition probabilities in a general birth-death process with arbitrary birth and death rates. In this paper, we first revisit the theory of continued fractions to obtain expressions for the Laplace transforms of these transition probabilities and make explicit an important derivation connecting transition probabilities and continued fractions. We then develop an efficient algorithm for computing these probabilities that analyzes the error associated with approximations in the method. We demonstrate that this error-controlled method agrees with known solutions and outperforms previous approaches to computing these probabilities. Finally, we apply our novel method to several important problems in ecology, evolution, and genetics

Individual Exposure to NO2 in Relation to Spatial and Temporal Exposure Indices in Stockholm, Sweden: The INDEX Study

Epidemiology studies of health effects from air pollution, as well as impact assessments, typically rely on ambient monitoring data or modelled residential levels. The relationship between these and personal exposure is not clear. To investigate personal exposure to NO2 and its relationship with other exposure metrics and time-activity patterns in a randomly selected sample of healthy working adults (20–59 years) living and working in Stockholm. Personal exposure to NO2 was measured with diffusive samplers in sample of 247 individuals. The 7-day average personal exposure was 14.3 µg/m3 and 12.5 µg/m3 for the study population and the inhabitants of Stockholm County, respectively. The personal exposure was significantly lower than the urban background level (20.3 µg/m3). In the univariate analyses the most influential determinants of individual exposure were long-term high-resolution dispersion-modelled levels of NO2 outdoors at home and work, and concurrent NO2 levels measured at a rural location, difference between those measured at an urban background and rural location and difference between those measured in busy street and at an urban background location, explaining 20, 16, 1, 2 and 4% (R2) of the 7-day personal NO2 variation, respectively. A regression model including these variables explained 38% of the variation in personal NO2 exposure. We found a small improvement by adding time-activity variables to the latter model (R2 = 0.44). The results adds credibility primarily to long-term epidemiology studies that utilise long-term indices of NO2 exposure at home or work, but also indicates that such studies may still suffer from exposure misclassification and dilution of any true effects. In contrast, urban background levels of NO2 are poorly related to individual exposure

The effect of fish stocking density and dietary supplementation of vitamin C and micronutrients (Mn, Zn and Se) on the development of systemic granulomatosis in juvenile meagre (Argyrosomus regius)

Systematic granulomatosis is a chronic disease that affects the majority of farmed meagre (A. regius). Nutritional imbalances and overcrowding can increase the risk to suffer oxidative stress, and consequently impact the incidence of granulomatosis. In order to evaluate this, juvenile meagre were fed five isolipidic (16.7 %) and isoproteic (49.6 %) fish meal and fish oil-based feeds prepared by adding different levels of vitamin C, minerals (Mn, Zn, Se) with constant vitamin E and K (300 and 35 mg kg-1, respectively): Diet KEC (100 mg kg-1C), Diet KEC+Mn/Zn/Se (100 mg kg-1C, 40 mg kg-1Mn, 200 mg kg-1Zn, 1.5 mg kg-1Se), Diet KECC (600 mg kg-1C), Diet KECCC (1,200 mg kg-1C), Diet KECCCC (3,200 mg kg-1C). All diets were tested at 3.20 kg m-3, but diets KECC and KECCCC was also tested at 6.20 kg m-3. Growth performance was only affected by stocking density, being lower at high density. Percentage of fish with granulomas was significantly lower in fish fed with the highest dietary vitamin C contents (KECCC and KECCCC) at low density. TBARS content was correlated with the percentage of granulomas in liver (R2=0.9439, y=0.003x-0.1242) denoting the involvement of an imbalance oxidative status in the appearance of granulomas. The present results show that high levels of vitamin C (1,200-3,200 mg kg-1C) and low stock density (3.20 kg m-3) favours the growth of juvenile meagre, reducing the lipid peroxidation indicators and decreasing the incidence of granulomas, which confirms that this pathology is mostly triggered by deficiency of antioxidant nutrients, particularly vitamin C