Dispersal of brown trout (Salmo trutta L.) fry in a low gradient stream - implications for egg stocking practices

Stocking of eggs is a common strategy to support declining or reintroduce extirpated salmonid populations. Data on how juveniles disperse from stocking points is crucial to be able to design efficient stocking programs. Detailed information of dispersal is limited for many salmonids, for example, brown trout. In this study, dispersal distance was measured at the end of the first growing season in a low gradient (0.7%) stream in Sweden where the trout population had been depleted. Eggs from 17 separate sets of parents were stocked as eyed eggs in March. During the following fall fry were sampled throughout the stream. The majority of the fry dispersed downstream and remained within a distance of 200 m from the stocking point with no difference between sizes of fry and the presence of a competing cohort or not. There was no dissimilarity in dispersal distances across offspring originating from different parents indicating absence of genetic influence. Our results suggest that, in streams similar to our study site, stocking points should be separated by approximately 330 m in order to avoid overlap in habitat use of fry from different stocking points and that the presence of competing cohorts, fry size and within population variability in dispersal can be neglected

In vitro toxicity testing using human pluripotent stem cell derivatives

Toxicity testing of chemicals, drug candidates, and food additives is in need of a change. The present methods, mainly consisting of animal models with their associated ethical concerns, are expensive, time-consuming, and importantly they are often poor predictors of the human in vivo toxicity. With the rapid biotechnology development, a paradigm shift for toxicity testing is emerging, focusing on bioinformatics, computational toxicity, systems biology, and cell-based in vitro models. The aim of this thesis was to investigate the utility of using cells, i.e. hepatocytes and cardiomyocytes, derived from human pluripotent stem cells (hPSC) as in vitro models for toxicity testing. The first part explored the feasibility of using hPSC-derived hepatocytes to study toxic drug exposure, and in addition investigated the relevancy of the cellular response. The second and major part of this thesis focused on hPSC-derived cardiomyocytes and the in-depth study of doxorubicin-induced toxicity. The studies revealed that the differentiation processes and culturing of hPSC-derivatives are stable and reproducible to form the basis for in vitro models for toxicity testing, even for longer studies over two weeks. The hepatocytes and the cardiomyocytes showed sensitivity towards the toxic compounds and both cell models dis-played a relevant cellular response to the toxic exposure. For example, the hepatocytes showed evidence of steatosis and phospholipidosis when incubated with hepatotoxic compounds over time. Besides an evident effect of doxorubicin on the cardiomyocyte function, the cells also proved to be useful for more in-depth mechanistic evaluations, as these studies gave insight, on multiple biological levels, in plausible mechanisms and identified potential biomarkers for doxorubicin-induced cardiotoxicity. In conclusion, this thesis presents findings that supports the vision and strategy of using in vitro models based on hPSC-derivatives together with advanced omics technologies for toxicity testing and risk assessment of drugs, food additives, and chemicals

Investerarforum och aktiehandel : En kvantitativ studie av investerarforum och dess förmåga att förutsäga aktiehandel

Internetbaserade investerarforum har blivit en allt viktigare källa till information för investerare. Forumen fungerar på så sätt att investerare med varierande kunskapsnivå delger sina funderingar och förhoppningar om företag och hur deras aktiers avkastning kan komma att se ut. Syftet med studien är att undersöka huruvida foruminläggsfrekvens och sentiment i foruminläggen kan indikera kommande förändringar i mindre bolags aktiers handelsrelaterade variabler. Totalt granskas elva bolags aktier och 40 055 foruminlägg. Sambanden mellan investerarforumen och aktiehandeln undersöks med en bivariat korrelationsanalys. Studien finner inte statistiskt signifikanta resultat för att sentimentnivå kan antyda aktiers kommande avkastning vilket styrker att aktiemarknadens effektivitet. Resultatet visar däremot att inläggsfrekvens korrelerar positivt med aktiers volatilitet, omsättning, volym och avslut

Investerarforum och aktiehandel : En kvantitativ studie av investerarforum och dess förmåga att förutsäga aktiehandel

Internetbaserade investerarforum har blivit en allt viktigare källa till information för investerare. Forumen fungerar på så sätt att investerare med varierande kunskapsnivå delger sina funderingar och förhoppningar om företag och hur deras aktiers avkastning kan komma att se ut. Syftet med studien är att undersöka huruvida foruminläggsfrekvens och sentiment i foruminläggen kan indikera kommande förändringar i mindre bolags aktiers handelsrelaterade variabler. Totalt granskas elva bolags aktier och 40 055 foruminlägg. Sambanden mellan investerarforumen och aktiehandeln undersöks med en bivariat korrelationsanalys. Studien finner inte statistiskt signifikanta resultat för att sentimentnivå kan antyda aktiers kommande avkastning vilket styrker att aktiemarknadens effektivitet. Resultatet visar däremot att inläggsfrekvens korrelerar positivt med aktiers volatilitet, omsättning, volym och avslut

Investerarforum och aktiehandel : En kvantitativ studie av investerarforum och dess förmåga att förutsäga aktiehandel

Internetbaserade investerarforum har blivit en allt viktigare källa till information för investerare. Forumen fungerar på så sätt att investerare med varierande kunskapsnivå delger sina funderingar och förhoppningar om företag och hur deras aktiers avkastning kan komma att se ut. Syftet med studien är att undersöka huruvida foruminläggsfrekvens och sentiment i foruminläggen kan indikera kommande förändringar i mindre bolags aktiers handelsrelaterade variabler. Totalt granskas elva bolags aktier och 40 055 foruminlägg. Sambanden mellan investerarforumen och aktiehandeln undersöks med en bivariat korrelationsanalys. Studien finner inte statistiskt signifikanta resultat för att sentimentnivå kan antyda aktiers kommande avkastning vilket styrker att aktiemarknadens effektivitet. Resultatet visar däremot att inläggsfrekvens korrelerar positivt med aktiers volatilitet, omsättning, volym och avslut

Effects of egg stocking on density, distribution, and size of young-of-year brown trout (Salmo trutta) in a large boreal river in northern Sweden

An understanding of egg densities and juvenile production is critical in salmonid egg stocking projects, but the question is not deeply studied. Given that managers rely on the number of young of the year (YOY) fish to evaluate stocking success, this knowledge gap poses a major challenge. We studied effects of two stocking levels on YOY brown trout at different downstream distances (0-600 m) from the stocking point. Density increased significantly with increasing distance from the stocking point when 60,000 eggs were stocked but not when 30,000 eggs were stocked. Body length was not related to distance from the stocking point and only moderately negatively related to density. We conclude that the results of egg stocking can be difficult to interpret because site-specific density may vary with distance from the stocking point and the number of eggs stocked

Artificial neural networks improve and simplify intensive care mortality prognostication: a national cohort study of 217,289 first-time intensive care unit admissions

Purpose We investigated if early intensive care unit (ICU) scoring with the Simplified Acute Physiology Score (SAPS 3) could be improved using artificial neural networks (ANNs). Methods All first-time adult intensive care admissions in Sweden during 2009-2017 were included. A test set was set aside for validation. We trained ANNs with two hidden layers with random hyper-parameters and retained the best ANN, determined using cross-validation. The ANNs were constructed using the same parameters as in the SAPS 3 model. The performance was assessed with the area under the receiver operating characteristic curve (AUC) and Brier score. Results A total of 217,289 admissions were included. The developed ANN (AUC 0.89 and Brier score 0.096) was found to be superior (p textless10-15 for AUC and p textless10-5 for Brier score) in early prediction of 30-day mortality for intensive care patients when compared with SAPS 3 (AUC 0.85 and Brier score 0.109). In addition, a simple, eight-parameter ANN model was found to perform just as well as SAPS 3, but with better calibration (AUC 0.85 and and Brier score 0.106, p textless10-5). Furthermore, the ANN model was superior in correcting mortality for age. Conclusion ANNs can outperform the SAPS 3 model for early prediction of 30-day mortality for intensive care patients

Data from: Expression profiling of human pluripotent stem cell-derived cardiomyocytes exposed to doxorubicin—integration and visualization of multi-omics data

Anthracyclines, such as doxorubicin, are highly efficient chemotherapeutic agents against a variety of cancers. However, anthracyclines are also among the most cardiotoxic therapeutic drugs presently on the market. Chemotherapeutic-induced cardiomyopathy is one of the leading causes of disease and mortality in cancer survivors. The exact mechanisms responsible for doxorubicin-induced cardiomyopathy are not completely known, but the fact that the cardiotoxicity is dose-dependent and that there is a variation in time-to-onset of toxicity, and gender- and age differences suggests that several mechanisms may be involved. In this study, we investigated doxorubicin-induced cardiotoxicity in human pluripotent stem cell-derived cardiomyocytes using proteomics. In addition, different sources of omics data (protein, mRNA, and microRNA) from the same experimental setup were further combined and analyzed using newly developed methods to identify differential expression in data of various origin and types. Subsequently, the results were integrated in order to generate a combined visualization of the findings. In our experimental model system, we exposed cardiomyocytes derived from human pluripotent stem cells to doxorubicin for up to 2 days, followed by a wash-out period of additionally 12 days. Besides an effect on the cell morphology and cardiomyocyte functionality, the data show a strong effect of doxorubicin on all molecular levels investigated. Differential expression patterns that show a linkage between the proteome, transcriptome, and the regulatory microRNA network, were identified. These findings help to increase the understanding of the mechanisms behind anthracycline-induced cardiotoxicity and suggest putative biomarkers for this condition