Novel tag-based method for measuring tailbeat frequency and variations in amplitude in fish

The tailbeat frequency (TBF) together with tailbeat amplitude (TBA) of fish are tightly correlated with swimming speed. In addition, these parameters can be used as indicators of metabolic rate and general activity level, provided that appropriate calibration studies have been performed in the laboratory. If an implantable bio-logger could measure TBF and TBA, it would, therefore, have great potential as a tool to monitor swimming behaviours and bioenergetics over extended periods of time in free roaming fish within natural or farm environments. The purpose of this study was, therefore, to establish a method for deriving accurate TBF and variations in TBA from activity tags that log high-resolution acceleration data. We used 6 tagged Atlantic salmon (Salmo salar) of ≈1 kg and subjected them to two types of swim trials in a large swim tunnel system. Test speeds were either incrementally increased in 20-min intervals until steady swimming ceased, or constant speed of 60 cm s−1 was given in a 4-h sustained test. The TBFs were visually observed by camera and compared with computed values from the activity tags. In the incremental trials the TBF increased linearly with swimming speed, while it remained constant during the 4 h of sustained swimming. The TBFs measured by activity tags were within ± 0.1 beat s−1 of the visual measurements across the swim speeds tested between 30 to 80 cm s−1. Furthermore, TBF and its corresponding relative swim speed were consistent between trial type. The relative TBA increased with swimming speed as a power function, showing that the fish relies on changes in both amplitude and frequency of tail movements when swimming at higher speeds, while adjustments of amplitude only play a minor part at lower speeds. These results demonstrate that TBFs can be measured accurately via activity tags, and thus be used to infer swimming activities and bioenergetics of free roaming fish. Furthermore, it is also possible to estimate changes in TBA via activity tags which allows for more nuanced assessments of swimming patterns in free roaming fish.publishedVersio

Oxygen gradients affect behaviour of caged Atlantic salmon Salmo salar

Dissolved oxygen (DO) conditions in marine aquaculture cages are heterogeneous and fluctuate rapidly. Here, by temporarily wrapping a tarpaulin around the top 0 to 6 m of a marine cage (~2000 m3), we manipulated DO to evaluate the behavioural response of Atlantic salmon Salmo salar to hypoxia. Videos were recorded before, during and after DO manipulation at 3 m depth while vertical profiles of temperature, salinity, DO and fish density were continuously measured. The trial was repeated 4 times over a 2 wk period. Temperature and salinity profiles varied little across treatment periods; however, DO saturation was reduced at all depths in all replicate trials during the tarpaulin treatment compared to the periods before or after. In 3 out of 4 trials, swim speeds were 1.5 to 2.7 times slower during the tarpaulin treatment than the before or after periods. Significant changes in vertical distribution of fish density and DO were observed between treatment periods in all replicate trials; salmon swam either above or below the most hypoxic depth layer (59 to 62% DO saturation). In a regression tree analysis, the relative influence of DO in determining fish distribution was 17%, while temperature (39%) and salinity (44%) explained the majority of variation. Our results demonstrate that salmon are capable of modifying their distribution and possibly activity levels in response to intermediate DO levels, but that DO is not a primary driver of behaviour at the saturation levels examined in this study

Sex differences in brain atrophy in dementia with Lewy bodies

\ua9 2023 The Authors. Alzheimer\u27s & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer\u27s Association.INTRODUCTION: Sex influences neurodegeneration, but it has been poorly investigated in dementia with Lewy bodies (DLB). We investigated sex differences in brain atrophy in DLB using magnetic resonance imaging (MRI). METHODS: We included 436 patients from the European-DLB consortium and the Mayo Clinic. Sex differences and sex-by-age interactions were assessed through visual atrophy rating scales (n = 327; 73 \ub1 8 years, 62% males) and automated estimations of regional gray matter volume and cortical thickness (n = 165; 69 \ub1 9 years, 72% males). RESULTS: We found a higher likelihood of frontal atrophy and smaller volumes in six cortical regions in males and thinner olfactory cortices in females. There were significant sex-by-age interactions in volume (six regions) and cortical thickness (seven regions) across the entire cortex. DISCUSSION: We demonstrate that males have more widespread cortical atrophy at younger ages, but differences tend to disappear with increasing age, with males and females converging around the age of 75. Highlights: Male DLB patients had higher odds for frontal atrophy on radiological visual rating scales. Male DLB patients displayed a widespread pattern of cortical gray matter alterations on automated methods. Sex differences in gray matter measures in DLB tended to disappear with increasing age

Ploidy elicits a whole-genome dosage effect: growth of triploid Atlantic salmon is linked to the genetic origin of the second maternal chromosome set

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Estimating the Effects of Immigration Status on Mental Health Care Utilizations in the United States

Immigration status is a likely deterrent of mental health care utilization in the United States. Using the Medical Expenditure Panel Survey and National Health Interview survey from 2002 to 2006, multivariable logistic regressions were used to estimate the effects of immigration status on mental health care utilization among patients with depression or anxiety disorders. Multivariate regressions showed that immigrants were significantly less likely to take any prescription drugs, but not significantly less likely to have any physician visits compared to US-born citizens. Results also showed that improving immigrants’ health care access and health insurance coverage could potentially reduce disparities between US-born citizens and immigrants by 14–29% and 9–28% respectively. Policy makers should focus on expanding the availability of regular sources of health care and immigrant health coverage to reduce disparities on mental health care utilization. Targeted interventions should also focus on addressing immigrants’ language barriers, and providing culturally appropriate services

Velferdsindikatorer for oppdrettslaks: Hvordan vurdere og dokumentere fiskevelferd - Del A. fiskevelferd og oppdrettslaks, kunnskap og teoretisk bakgrunn

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Behavioural indicators of welfare in farmed fish

Behaviour represents a reaction to the environment as fish perceive it and is therefore a key element of fish welfare. This review summarises the main findings on how behavioural changes have been used to assess welfare in farmed fish, using both functional and feeling-based approaches. Changes in foraging behaviour, ventilatory activity, aggression, individual and group swimming behaviour, stereotypic and abnormal behaviour have been linked with acute and chronic stressors in aquaculture and can therefore be regarded as likely indicators of poor welfare. On the contrary, measurements of exploratory behaviour, feed anticipatory activity and reward-related operant behaviour are beginning to be considered as indicators of positive emotions and welfare in fish. Despite the lack of scientific agreement about the existence of sentience in fish, the possibility that they are capable of both positive and negative emotions may contribute to the development of new strategies (e. g. environmental enrichment) to promote good welfare. Numerous studies that use behavioural indicators of welfare show that behavioural changes can be interpreted as either good or poor welfare depending on the fish species. It is therefore essential to understand the species-specific biology before drawing any conclusions in relation to welfare. In addition, different individuals within the same species may exhibit divergent coping strategies towards stressors, and what is tolerated by some individuals may be detrimental to others. Therefore, the assessment of welfare in a few individuals may not represent the average welfare of a group and vice versa. This underlines the need to develop on-farm, operational behavioural welfare indicators that can be easily used to assess not only the individual welfare but also the welfare of the whole group (e. g. spatial distribution). With the ongoing development of video technology and image processing, the on-farm surveillance of behaviour may in the near future represent a low-cost, noninvasive tool to assess the welfare of farmed fish.Fundação para a Ciência e Tecnologia, Portugal [SFRH/BPD/42015/2007]info:eu-repo/semantics/publishedVersio

Racism as a determinant of health: a systematic review and meta-analysis

Despite a growing body of epidemiological evidence in recent years documenting the health impacts of racism, the cumulative evidence base has yet to be synthesized in a comprehensive meta-analysis focused specifically on racism as a determinant of health. This meta-analysis reviewed the literature focusing on the relationship between reported racism and mental and physical health outcomes. Data from 293 studies reported in 333 articles published between 1983 and 2013, and conducted predominately in the U.S., were analysed using random effects models and mean weighted effect sizes. Racism was associated with poorer mental health (negative mental health: r = -.23, 95% CI [-.24,-.21], k = 227; positive mental health: r = -.13, 95% CI [-.16,-.10], k = 113), including depression, anxiety, psychological stress and various other outcomes. Racism was also associated with poorer general health (r = -.13 (95% CI [-.18,-.09], k = 30), and poorer physical health (r = -.09, 95% CI [-.12,-.06], k = 50). Moderation effects were found for some outcomes with regard to study and exposure characteristics. Effect sizes of racism on mental health were stronger in cross-sectional compared with longitudinal data and in non-representative samples compared with representative samples. Age, sex, birthplace and education level did not moderate the effects of racism on health. Ethnicity significantly moderated the effect of racism on negative mental health and physical health: the association between racism and negative mental health was significantly stronger for Asian American and Latino(a) American participants compared with African American participants, and the association between racism and physical health was significantly stronger for Latino(a) American participants compared with African American participants.<br /