| 1. |
- Beck, Lisa J., et al.
(författare)
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Differing Mechanisms of New Particle Formation at Two Arctic Sites
- 2021
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 48:4
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Tidskriftsartikel (refereegranskat)abstract
- New particle formation in the Arctic atmosphere is an important source of aerosol particles. Understanding the processes of Arctic secondary aerosol formation is crucial due to their significant impact on cloud properties and therefore Arctic amplification. We observed the molecular formation of new particles from low-volatility vapors at two Arctic sites with differing surroundings. In Svalbard, sulfuric acid (SA) and methane sulfonic acid (MSA) contribute to the formation of secondary aerosol and to some extent to cloud condensation nuclei (CCN). This occurs via ion-induced nucleation of SA and NH3 and subsequent growth by mainly SA and MSA condensation during springtime and highly oxygenated organic molecules during summertime. By contrast, in an ice-covered region around Villum, we observed new particle formation driven by iodic acid but its concentration was insufficient to grow nucleated particles to CCN sizes. Our results provide new insight about sources and precursors of Arctic secondary aerosol particles.
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| 2. |
- Bekkevold, Dorte, et al.
(författare)
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Genetic monitoring uncovers long-distance marine feeding coupled with strong spatial segregation in sea trout (Salmo trutta L.) consistent at annual and decadal time scales
- 2024
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Ingår i: ICES JOURNAL OF MARINE SCIENCE. - 1054-3139 .- 1095-9289.
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Tidskriftsartikel (refereegranskat)abstract
- Genetic data have greatly increased means to understand fish marine migration behaviours at large spatial scale within a quantitative framework. The anadromous sea trout is a prized target of recreational fishery and an important ecosystem component in freshwater and marine coastal habitats in large parts of temperate northern Europe. Nonetheless, little is known about population distributions while feeding at sea. To reconcile notions about feeding migrations being predominantly locally restricted or not, we used SNP data for 3465 trout representing >100 rivers to identify population origins of 903 coastally feeding fish captured throughout the North Sea-Baltic Sea transition area. Across areas, coastal collections generally showed marked stock-mixing and overall 70:30% native:non-native fish with seasonal variation corresponding with spawning run timing. Data revealed strong spatial feeding segregation between trout from the Scandinavian Peninsula and the European continent. This is surprising given the short distances between areas, but is in alignment with strong genetic differentiation between populations in these areas. Estimation of stock complexity of coastal feeding aggregations showed no spatial trend through the North Sea-Baltic Sea transition area otherwise characterized by strong environmental clines. Analyses of scale samples collected in the 1950s indicate that stock-mixing was consistent over almost 70 years.
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| 3. |
- Brodersen, Jakob, et al.
(författare)
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Condition-dependent individual decision-making determines cyprinid partial migration
- 2008
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Ingår i: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 89:5, s. 1195-1200
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Tidskriftsartikel (refereegranskat)abstract
- Partial migration is a common phenomenon among many animals and occurs in many types of ecosystems. Understanding the mechanisms behind partial migration is of major importance for the understanding of population dynamics and, eventually, ecosystem processes. We studied the effects of food availability on the seasonal partial migration of cyprinid fish from a lake to connected streams during winter by the use of passive telemetry. Fish with increased access to food were found to migrate in higher proportion, earlier in the season, and to reside in the streams for a longer period compared to fish with decreased access to food. Furthermore, fewer unfed migrants returned to the lake, indicating higher overwinter mortality. Our results suggest that individual fish trade off safety from predation and access to food differently depending on their body condition, which results in a condition-dependent partial migration. Hence, our main conclusion is that individual decision-making is based on assessment of own condition which offers a mechanistic explanation to partial migration. Moreover, this may be of high importance for understanding population responses to environmental variation as well as ecosystem dynamics and stability. Read More: http://www.esajournals.org/doi/abs/10.1890/07-1318.1
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| 4. |
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| 5. |
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| 6. |
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| 7. |
- Brodersen, Jakob, et al.
(författare)
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Variable individual consistency in timing and destination of winter migrating fish
- 2012
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 8, s. 21-23
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Tidskriftsartikel (refereegranskat)abstract
- Migration is an important event in the life history of many animals, but there is considerable variation within populations in the timing and final destination. Such differential migration at the population level can be strongly determined by individuals showing different consistencies in migratory traits. By tagging individual cyprinid fish with uniquely coded electronic tags, and recording their winter migrations from lakes to streams for 6 consecutive years, we obtained highly detailed long-term information on the differential migration patterns of individuals. We found that individual migrants showed consistent site fidelities for over-wintering streams over multiple migratory seasons and that they were also consistent in their seasonal timing of migration. Our data also suggest that consistency itself can be considered as an individual trait, with migrants that exhibit consistent site fidelity also showing consistency in migratory timing. The finding of a mixture of both consistent and inconsistent individuals within a population furthers our understanding of intrapopulation variability in migration strategies, and we hypothesize that environmental variation can maintain such different strategies.
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| 8. |
- Brönmark, Christer, et al.
(författare)
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Regime shifts in shallow lakes: the importance of seasonal fish migration
- 2010
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Ingår i: Hydrobiologia. - : Springer Science and Business Media LLC. - 0018-8158 .- 1573-5117. ; 646:1, s. 91-100
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Konferensbidrag (refereegranskat)abstract
- Shallow eutrophic lakes commonly exist in two alternative stable states: a clear-water state and a turbid water state. A number of mechanisms, including both abiotic and biotic processes, buffer the respective states against changes, whereas other mechanisms likely drive transitions between states. Our earlier research shows that a large proportion of zooplanktivorous fish populations in shallow lakes undertake seasonal migrations where they leave the lake during winter and migrate back to the lake in spring. Based on our past research, we propose a number of scenarios of how feedback processes between the individual and ecosystem levels may affect stability of alternative stable states in shallow lakes when mediated by fish migration. Migration effects on shallow lakes result from processes at different scales, from the individual to the ecosystem. Our earlier research has shown that ecosystem properties, including piscivore abundance and zooplankton productivity, affect the individual state of zooplanktivorous fish, such as growth rate or condition. Individual state, in turn, affects the relative proportion and timing of migrating zooplanktivorous fish. This change, in turn, may stabilize states or cause runaway processes that eventually lead to state shifts. Consequently, such knowledge of processes coupled to seasonal migration of planktivorous fish should increase our understanding of shallow lake dynamics.
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| 9. |
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| 10. |
- Brönmark, Christer, et al.
(författare)
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Seasonal migration determined by a trade-off between predator avoidance and growth
- 2008
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Migration is a common phenomenon in many organisms, terrestrial as well as aquatic, and considerable effort has been spent to understand the evolution of migratory behaviour and its consequences for population and community dynamics. In aquatic systems, studies on migration have mainly been focused on commercially important fish species, such as salmon and trout. However, seasonal mass-migrations may occur also among other freshwater fish, e.g. in cyprinids that leave lakes and migrate into streams and wetlands in the fall and return back to the lake in spring. In a conceptual model, we hypothesized that this is an adaptive behaviour in response to seasonal changes in predation (P) and growth (G) and that migrating fish change habitat so as to minimise the ratio between predation mortality and growth rate (P/G). Estimates from bioenergetic modelling showed that seasonal changes in the ratio between predator consumption rate and prey growth rate followed the predictions from the conceptual model and also gave more precise predictions for the timing of the habitat change. By quantifying the migration of more than 1800 individually marked fish, we showed that actual migration patterns followed predictions with a remarkable accuracy, suggesting that migration patterns have evolved in response to seasonally fluctuating trade-offs between predator avoidance and foraging gains. Thus, the conceptual model provides a mechanistic understanding to mass–migration in prey fish. Further, we also show that the dominant prey fish is actually absent from the lake during a major part of the year, which should have strong implications for the dynamics of the lake ecosystem through direct and indirect food-web interactions.
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| 11. |
- Chapman, Ben, et al.
(författare)
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A foraging cost of migration for a partially migratory cyprinid fish
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:5
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Tidskriftsartikel (refereegranskat)abstract
- Migration has evolved as a strategy to maximise individual fitness in response to seasonally changing ecological and environmental conditions. However, migration can also incur costs, and quantifying these costs can provide important clues to the ultimate ecological forces that underpin migratory behaviour. A key emerging model to explain migration in many systems posits that migration is driven by seasonal changes to a predation/growth potential (p/g) trade-off that a wide range of animals face. In this study we assess a key assumption of this model for a common cyprinid partial migrant, the roach Rutilus rutilus, which migrates from shallow lakes to streams during winter. By sampling fish from stream and lake habitats in the autumn and spring and measuring their stomach fullness and diet composition, we tested if migrating roach pay a cost of reduced foraging when migrating. Resident fish had fuller stomachs containing more high quality prey items than migrant fish. Hence, we document a feeding cost to migration in roach, which adds additional support for the validity of the p/g model of migration in freshwater systems.
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| 12. |
- Chapman, Ben, et al.
(författare)
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Partial migration in fishes: causes and consequences.
- 2012
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 81:2, s. 456-478
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Tidskriftsartikel (refereegranskat)abstract
- Partial migration, where only some individuals from a population migrate, has been widely reported in a diverse range of animals. In this paper, what is known about the causes and consequences of partial migration in fishes is reviewed. Firstly, the ultimate and proximate drivers of partial migration are reflected upon: what ecological factors can shape the evolution of migratory dimorphism? How is partial migration maintained over evolutionary timescales? What proximate mechanisms determine whether an individual is migratory or remains resident? Following this, the consequences of partial migration are considered, in an ecological and evolutionary context, and also in an applied sense. Here it is argued that understanding the concept of partial migration is crucial for fisheries and ecosystem managers, and can provide information for conservation strategies. The review concludes with a reflection on the future opportunities in this field, and the avenues of research that are likely to be fruitful to shed light on the enduring puzzle of partial migration in fishes.
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| 13. |
- Chapman, Ben, et al.
(författare)
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Partial migration in fishes: definitions, methodologies and taxonomic distribution.
- 2012
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 81:2, s. 479-499
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Tidskriftsartikel (refereegranskat)abstract
- Partial migration, where populations are composed of both migratory and resident individuals, is extremely widespread across the animal kingdom. Researchers studying fish movements have long recognized that many fishes are partial migrants, however, no detailed taxonomic review has ever been published. In addition, previous work and synthesis has been hampered by a varied lexicon associated with this phenomenon in fishes. In this review, definitions and important concepts in partial migration research are discussed, and a classification system of the different forms of partial migration in fishes introduced. Next, a detailed taxonomic overview of partial migration in this group is considered. Finally, methodological approaches that ichthyologists can use to study this fascinating phenomenon are reviewed. Partial migration is more widespread amongst fishes than previously thought, and given the array of techniques available to fish biologists to study migratory variation the future of the field looks promising.
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| 14. |
- Chapman, Ben, et al.
(författare)
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To boldly go: individual differences in boldness influence migratory tendency.
- 2011
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X. ; 14, s. 871-876
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Tidskriftsartikel (refereegranskat)abstract
- Ecology Letters (2011) ABSTRACT: Partial migration, whereby only a fraction of the population migrates, is thought to be the most common type of migration in the animal kingdom, and can have important ecological and evolutionary consequences. Despite this, the factors that influence which individuals migrate and which remain resident are poorly understood. Recent work has shown that consistent individual differences in personality traits in animals can be ecologically important, but field studies integrating personality traits with migratory behaviour are extremely rare. In this study, we investigate the influence of individual boldness, an important personality trait, upon the migratory propensity of roach, a freshwater fish, over two consecutive migration seasons. We assay and individually tag 460 roach and show that boldness influences migratory propensity, with bold individuals being more likely to migrate than shy fish. Our data suggest that an extremely widespread personality trait in animals can have significant ecological consequences via influencing individual-level migratory behaviour.
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| 15. |
- Eriksson, Daniel, et al.
(författare)
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Common genetic variation in the autoimmune regulator (AIRE) locus is associated with autoimmune Addison’s disease in Sweden
- 2018
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Autoimmune Addison's disease (AAD) is the predominating cause of primary adrenal failure. Despite its high heritability, the rarity of disease has long made candidate-gene studies the only feasible methodology for genetic studies. Here we conducted a comprehensive reinvestigation of suggested AAD risk loci and more than 1800 candidate genes with associated regulatory elements in 479 patients with AAD and 2394 controls. Our analysis enabled us to replicate many risk variants, but several other previously suggested risk variants failed confirmation. By exploring the full set of 1800 candidate genes, we further identified common variation in the autoimmune regulator (AIRE) as a novel risk locus associated to sporadic AAD in our study. Our findings not only confirm that multiple loci are associated with disease risk, but also show to what extent the multiple risk loci jointly associate to AAD. In total, risk loci discovered to date only explain about 7% of variance in liability to AAD in our study population.
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| 16. |
- Fahlén Bergh, Cecilia, et al.
(författare)
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Factors of importance for discontinuation of thiazides associated with hyponatremia in Sweden: A population-based register study.
- 2019
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Ingår i: Pharmacoepidemiology and Drug Safety. - : Wiley. - 1053-8569 .- 1099-1557.
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: In a patient with clinically significant hyponatremia without other clear causes, thiazide treatment should be replaced with another drug. Data describing to which extent this is being done are scarce. The aim of this study was to investigate sociodemographic and socioeconomic factors that may be of importance for the withdrawal of thiazide diuretics in patients hospitalized due to hyponatremia.METHODS: The study population was sampled from a case-control study investigating individuals hospitalized with a main diagnosis of hyponatremia. For every case, four matched controls were included. In the present study, cases (n = 5204) and controls (n = 7425) that had been dispensed a thiazide diuretic prior to index date were identified and followed onward regarding further dispensations. To investigate the influence of socioeconomic and sociodemographic factors, multiple logistic regression was used.RESULTS: The crude prevalence of thiazide withdrawal for cases and controls was 71.9% and 10.8%, respectively. Thiazide diuretics were more often withdrawn in medium-sized towns (adjusted OR, 1.52; 95% CI, 1.21-1.90) and rural areas (aOR, 1.81; 95% CI, 1.40-2.34) compared with metropolitan areas and less so among divorced (aOR, 0.72; 95% CI, 0.53-0.97). However, education, employment status, income, age, country of birth, and gender did not influence withdrawal of thiazides among patients with hyponatremia.CONCLUSIONS: Thiazide diuretics were discontinued in almost three out of four patients hospitalized due to hyponatremia. Educational, income, gender, and most other sociodemographic and socioeconomic factors were not associated with withdrawal of thiazides.
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| 17. |
- Granholm, Anders, et al.
(författare)
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Empirical meropenem versus piperacillin/tazobactam for adult patients with sepsis (EMPRESS) trial : Protocol
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Ingår i: Acta Anaesthesiologica Scandinavica. - 0001-5172.
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Tidskriftsartikel (refereegranskat)abstract
- Background: Piperacillin/tazobactam may be associated with less favourable outcomes than carbapenems in patients with severe bacterial infections, but the certainty of evidence is low. Methods: The Empirical Meropenem versus Piperacillin/Tazobactam for Adult Patients with Sepsis (EMPRESS) trial is an investigator-initiated, international, parallel-group, randomised, open-label, adaptive clinical trial with an integrated feasibility phase. We will randomise adult, critically ill patients with sepsis to empirical treatment with meropenem or piperacillin/tazobactam for up to 30 days. The primary outcome is 30-day all-cause mortality. The secondary outcomes are serious adverse reactions within 30 days; isolation precautions due to resistant bacteria within 30 days; days alive without life support and days alive and out of hospital within 30 and 90 days; 90- and 180-day all-cause mortality and 180-day health-related quality of life. EMPRESS will use Bayesian statistical models with weak to somewhat sceptical neutral priors. Adaptive analyses will be conducted after follow-up of the primary outcome for the first 400 participants concludes and after every 300 subsequent participants, with adaptive stopping for superiority/inferiority and practical equivalence (absolute risk difference <2.5%-points) and response-adaptive randomisation. The expected sample sizes in scenarios with no, small or large differences are 5189, 5859 and 2570 participants, with maximum 14,000 participants and ≥99% probability of conclusiveness across all scenarios. Conclusions: EMPRESS will compare the effects of empirical meropenem against piperacillin/tazobactam in adult, critically ill patients with sepsis. Due to the pragmatic, adaptive design with high probability of conclusiveness, the trial results are expected to directly inform clinical practice.
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| 18. |
- Grinderslev, Jakob B., et al.
(författare)
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Polymorphism and solid solutions of trimethylammonium monocarboranes
- 2022
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 51:41, s. 15806-15815
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Tidskriftsartikel (refereegranskat)abstract
- Metal closo-boranes have recently received significant attention as solid-state electrolytes due to their high thermal and electrochemical stability, and the weak interaction between the cat- and anion, facilitating fast ionic conductivity. Here we report a synthesis method for obtaining a novel mixed closo-carborane compound, [NH(CH3)3][(CB8H9)0.26(CB9H10)0.66(CB11H12)0.08]. The crystal structures are investigated for [NH(CH3)3][CB9H10] and [NH(CH3)3][(CB8H9)0.26(CB9H10)0.66(CB11H12)0.08], revealing that the latter forms a solid solution isostructural to [NH(CH3)3][CB9H10]. The compounds exhibit polymorphism as a function of temperature, and we report the discovery of four polymorphs of [NH(CH3)3][CB9H10] and four isostructural solid solution [NH(CH3)3][(CB8H9)0.26(CB9H10)0.66(CB11H12)0.08], along with a high-temperature decomposition intermediate of the latter. The α-polymorph is an ordered structure, with increasing amounts of disorder for the β- and γ-polymorphs, while the high temperature δ- and ϵ-polymorphs at T > 476 K are fully disordered on both the cation and anion site. These new compounds may be used as precursors for new types of solid-state ionic conductors.
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| 19. |
- Hansen, Joan H., et al.
(författare)
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Ecological consequences of animal migration : Prey partial migration affects predator ecology and prey communities
- 2020
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Ingår i: Ecosystems. - : Springer Nature. - 1432-9840 .- 1435-0629. ; 23:2, s. 292-306
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Tidskriftsartikel (refereegranskat)abstract
- Patterns of animal migration and the ecological forces that shape them have been studied for centuries. Yet ecological impacts caused by the migration, such as altered predator–prey interactions and effects on community structure, remain poorly understood. This is to a large extent due to the scarcity of naturally replicated migration systems with negative controls, that is, ecosystems without migration. In this study, we tested whether partial migration of certain species within the overall prey community affects foraging ecology of top predators and thereby alters energy pathways in food webs. We carried out the study in independent replicated freshwater lake systems, four with and four without opportunity for prey migration. Specifically, we compared predator foraging mode in lakes where cyprinid prey fish perform seasonal partial migrations into connected streams with lakes lacking migratory opportunities for prey fish. We found clear seasonal bottom-up effects of prey migration on predators, including changes in size structure and total biomass of ingested prey, size-specific changes in littoral versus pelagic origin of diet, and a higher degree of feast-and-famine for predators in systems with migratory prey. Our analyses further showed that partially migratory prey species constitute a larger part of the prey community in systems that allow migration. Hence, prey migrations have important implications for predator foraging ecology and may cause seasonal shifts in the importance of their supporting energy pathways. We suggest that such bottom-up effects of partial migration may be a widespread phenomenon both in aquatic and in terrestrial ecosystems. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
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| 20. |
- Hansson, Lars-Anders, et al.
(författare)
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A lake as a microcosm : Reflections on developments in aquatic ecology
- 2013
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Ingår i: Aquatic Ecology. - : Springer Science and Business Media LLC. - 1386-2588 .- 1573-5125. ; 47, s. 125-135
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, we aim at relating Forbes' remarkable paper on "The lake as a microcosm", published 125 years ago, to the present status of knowledge in our own research group. Hence, we relate the observations Forbes made to our own microcosm, Lake Krankesjon in southern Sweden, that has been intensively studied by several research groups for more than three decades. Specifically, we focus on the question: Have we made any significant progress or did Forbes and colleagues blaze the trail through the unknown wilderness and we are mainly paving that intellectual road? We conclude that lakes are more isolated than many other biomes, but have, indeed, many extensions, for example, input from the catchment, fishing and fish migration. We also conclude that irrespective of whether lakes should be viewed as microcosms or not, the paper by Forbes has been exceptionally influential and still is, especially since it touches upon almost all aspects of the lake ecosystem, from individual behaviour to food web interactions and environmental issues. Therefore, there is no doubt that even if 125 years have passed, Forbes' paper still is a source of inspiration and deserves to be read. Hence, although aquatic ecology has made considerable progress over the latest century, Forbes might be viewed as one of the major pioneers and visionary scientists of limnology.
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| 21. |
- Hansson, Lars-Anders, et al.
(författare)
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Consequences of fish predation, migration, and juvenile ontogeny on zooplankton spring dynamics
- 2007
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Ingår i: Limnology and Oceanography. - 1939-5590. ; 52:2, s. 696-706
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Tidskriftsartikel (refereegranskat)abstract
- In order to disentangle if and when resource supply and adult and young-of-the-year (0+) fish predation affect zooplankton dynamics during spring, we monitored zooplankton during three consecutive years in a lake in southern Sweden. We also experimentally assessed 0+ fish predation rates and estimated changes in predation rates of adult fish on zooplankton. Decline in abundances of large-sized zooplankters in early spring was not caused by 0+ fish predation. Instead, this decline was most likely a combined result of size-selective predation from adult fish (stationary in the lake and from those returning from surrounding streams) and competition for diminishing algal food resources. On the other hand, the decline in medium-sized zooplankton in the lake during spring was strongly affected by 0+ fish. Hence, during spring, zooplankton are facing predation both from adult fish selecting large prey and from 0+ fish, which start feeding on small-sized prey and eventually switch to larger. Neither predation by different ontogenetic stages of fish (adult and 0+) nor resource supply shape the zooplankton spring dynamics, but rather they affect the timing and strength of these events. 0+ cyprinids tend to have stronger effect on zooplankton dynamics than other taxa of 0+ fish. A combination of predation from adult and 0+ fish during spring is the main mechanism behind the crash of the zooplankton community, which in many lakes leads to the termination of the clear-water phase.
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| 22. |
- Hulthén, Kaj, et al.
(författare)
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A predation cost to bold fish in the wild
- 2017
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Studies of predator-mediated selection on behaviour are critical for our understanding of the evolution and maintenance of behavioural diversity in natural populations. Consistent individual differences in prey behaviour, especially in the propensity to take risks (“boldness”), are widespread in the animal kingdom. Theory predicts that individual behavioural types differ in a cost-benefit trade-off where bolder individuals benefit from greater access to resources while paying higher predation-risk costs. However, explicitly linking predation events to individual behaviour under natural conditions is challenging and there is currently little data from the wild. We assayed individual behaviour and electronically tagged hundreds of fish (roach, Rutilus rutilus) before releasing them into their lake of origin, thereby exposing them to predation risk from avian apex predators (cormorants, Phalacrocorax carbo). Scanning for regurgitated tags at the cormorant roosting site provided data on individual predation events. We found that fish with higher boldness have a greater susceptibility to cormorant predation compared to relatively shy, risk-averse individuals. Our findings hereby provide unique and direct evidence of behavioural type-dependent predation vulnerability in the wild, i.e. that there is a predation cost to boldness, which is critical for our understanding of the evolution and maintenance of behavioural diversity in natural populations.
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| 23. |
- Hulthén, Kaj, et al.
(författare)
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Timing and synchrony of migration in a freshwater fish : Consequences for survival
- 2022
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 91:10, s. 2103-2112
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Tidskriftsartikel (refereegranskat)abstract
- Animal migration is one of the most spectacular and visible behavioural phenomena in nature with profound implications for a range of ecological and evolutionary processes. Successful migration hinges on the ability to exploit temporary resources (e.g. food) and evade threats (e.g. predators) as they arise, and thus the timing of migration is often regarded as a dominant predictor of individual migratory success. However, with the exception of intensively studied taxa (mainly birds), relatively few studies have investigated inter-individual annual and seasonal variation in migratory timing and performance, or tested predictions on how migration across high and low predation-risk habitats may exert selection on migratory timing. In particular, studies that assess the survival consequences of variation in migratory timing remain rare, which is most likely due to the logistical challenges associated with monitoring survival success and population-level characteristics simultaneously. Here, we address the above-mentioned questions using roach Rutilus rutilus, a fish that migrates from lakes characterised by high predation risk into low-risk streams during winter. Specifically, we used individual-based tracking of roach in two European lake systems over multiple migration periods (9 and 7 years respectively), to obtain highly detailed (year-round scheduling, repeat journeys and the fate of individuals) data on the variability/synchrony of migratory timing in spring and autumn respectively. We report seasonal differences in the variability of migratory timing, with lower variance and higher migration synchrony in spring lake arrival timing as compared to autumn lake departure timing. Furthermore, the timing of autumn migration is more variable across years than the timing of spring migration. Second, we find that later arrival to the lake habitat is positively associated with apparent survival from 1 year to the next, whereas we found no effect of lake departure timing on survival probability. These findings represent rare evidence showing how intraspecific variation in timing in migratory fish differs across years and seasons, and how variation in timing can translate into survival consequences for prey in systems characterised by high predation risk.
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| 24. |
- Landegren, Nils, et al.
(författare)
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Autoantibodies Targeting a Collecting Duct-Specific Water Channel in Tubulointerstitial Nephritis
- 2016
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Ingår i: Journal of the American Society of Nephrology: JASN. - 1533-3450 .- 1046-6673. ; 27:10, s. 3220-3228
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Tidskriftsartikel (refereegranskat)abstract
- Tubulointerstitial nephritis is a common cause of kidney failure and may have diverse etiologies. This form of nephritis is sometimes associated with autoimmune disease, but the role of autoimmune mechanisms in disease development is not well understood. Here, we present the cases of three patients with autoimmune polyendocrine syndrome type 1 who developed tubulointerstitial nephritis and ESRD in association with autoantibodies against kidney collecting duct cells. One of the patients developed autoantibodies targeting the collecting duct-specific water channel aquaporin 2, whereas autoantibodies of the two other patients reacted against the HOXB7 or NFAT5 transcription factors, which regulate the aquaporin 2 promoter. Our findings suggest that tubulointerstitial nephritis developed in these patients as a result of an autoimmune insult on the kidney collecting duct cells.
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| 25. |
- Leinonen, Ville, et al.
(författare)
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Comparison of particle number size distribution trends in ground measurements and climate models
- 2022
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 22:19, s. 12873-12905
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Tidskriftsartikel (refereegranskat)abstract
- Despite a large number of studies, out of all drivers of radiative forcing, the effect of aerosols has the largest uncertainty in global climate model radiative forcing estimates. There have been studies of aerosol optical properties in climate models, but the effects of particle number size distribution need a more thorough inspection. We investigated the trends and seasonality of particle number concentrations in nucleation, Aitken, and accumulation modes at 21 measurement sites in Europe and the Arctic. For 13 of those sites, with longer measurement time series, we compared the field observations with the results from five climate models, namely EC-Earth3, ECHAM-M7, ECHAM-SALSA, NorESM1.2, and UKESM1. This is the first extensive comparison of detailed aerosol size distribution trends between in situ observations from Europe and five earth system models (ESMs). We found that the trends of particle number concentrations were mostly consistent and decreasing in both measurements and models. However, for many sites, climate models showed weaker decreasing trends than the measurements. Seasonal variability in measured number concentrations, quantified by the ratio between maximum and minimum monthly number concentration, was typically stronger at northern measurement sites compared to other locations. Models had large differences in their seasonal representation, and they can be roughly divided into two categories: for EC-Earth and NorESM, the seasonal cycle was relatively similar for all sites, and for other models the pattern of seasonality varied between northern and southern sites. In addition, the variability in concentrations across sites varied between models, some having relatively similar concentrations for all sites, whereas others showed clear differences in concentrations between remote and urban sites. To conclude, although all of the model simulations had identical input data to describe anthropogenic mass emissions, trends in differently sized particles vary among the models due to assumptions in emission sizes and differences in how models treat size-dependent aerosol processes. The inter-model variability was largest in the accumulation mode, i.e. sizes which have implications for aerosol–cloud interactions. Our analysis also indicates that between models there is a large variation in efficiency of long-range transportation of aerosols to remote locations. The differences in model results are most likely due to the more complex effect of different processes instead of one specific feature (e.g. the representation of aerosol or emission size distributions). Hence, a more detailed characterization of microphysical processes and deposition processes affecting the long-range transport is needed to understand the model variability.
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| 26. |
- Leone, Marica, et al.
(författare)
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FAMILIAL LIABILITY FOR ENDOCRINE-METABOLIC DISORDERS AND DEPRESSION
- 2021
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Ingår i: European Neuropsychopharmacology. - : Elsevier. - 0924-977X .- 1873-7862. ; 51, s. e112-e112
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: Endocrine-metabolic disorders are common in individuals with depression. Better understanding of the underlying factors contributing to their concomitant occurrence is needed. This study investigates the familial co-aggregation of depression and endocrine-metabolic disorders and estimates the contribution of genetic and environmental risk factors to their co-occurrence.Methods: We conducted a population-based cohort study using Swedish national data. A total of 2,263,311 individuals born between 1973 and 1996 were included and followed up until death, emigration, or December 31, 2013, whichever occurred first. Each participant was linked to their biological parents, allowing identification of full-, maternal half-, and paternal half-siblings. We investigated clinical diagnoses of depression and endocrine-metabolic disorders diagnosed at any point during the follow-up period, grouping the latter into autoimmune disorders (i.e., hypothyroidism, Graves’ disease, and type 1 diabetes) and non-autoimmune disorders (i.e., type 2 diabetes, obesity, and polycystic ovarian syndrome). Logistic regression and Cox proportional hazards regression were used to estimate the association between endocrine-metabolic disorders and depression within the same individual and across siblings. Quantitative genetic modeling was performed to investigate the relative contribution of genetic and environmental influences.Results: Individuals diagnosed with endocrine-metabolic disorders had significantly higher risk of depression, with odds ratios ranging from 1.43 [95% CI, 1.30-1.57] for Graves’ disease to 2.44 [2.37-2.50] for obesity. Overall, increased risks extended to full- and half-siblings. Quantitative genetic modeling showed that shared genetic factors explained the phenotypic correlations between endocrine-metabolic disorders and depression to different extents (ranging from 36% for autoimmune hypothyroidism, to 74% for obesity), except for type 1 diabetes, for which the association was mainly explained by non-shared environmental factors (84%).Discussion: Endocrine-metabolic disorders and depression co-occur in individuals and display familial co-aggregation. Shared genetic risk factors explained much of this relationship, but unique environmental influences also contributed significantly. These findings expand the current knowledge of the etiological sources of comorbidity between somatic and psychiatric disorders, which could guide future research aiming at identifying the pathophysiological mechanisms and potentially intervention targets.
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| 27. |
- Leone, Marica, et al.
(författare)
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Genetic and Environmental Contribution to the Co-Occurrence of Endocrine-Metabolic Disorders and Depression : A Nationwide Swedish Study of Siblings
- 2022
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Ingår i: American Journal of Psychiatry. - : HighWire Press. - 0002-953X .- 1535-7228. ; 179:11, s. 824-832
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Depression is common in individuals with endocrine-metabolic disorders and vice versa, and a better understanding of the underlying factors contributing to the comorbidity of these disorders is needed. This study investigated the familial coaggregation of depression and endocrine-metabolic disorders and estimated the contribution of genetic and environmental factors to their co-occurrence.METHODS: This population-based cohort study included 2.2 million individuals born in Sweden between 1973 and 1996, with follow-up through 2013. Participants were linked to their biological parents, allowing identification of full siblings, maternal half siblings, and paternal half siblings. Diagnoses of depression and endocrine-metabolic conditions were investigated, with the latter grouped into autoimmune disorders (autoimmune hypothyroidism, Graves' disease, and type 1 diabetes) and non-autoimmune disorders (type 2 diabetes, obesity, and polycystic ovary syndrome). Logistic regression and Cox regression were used to estimate the associations between endocrine-metabolic disorders and depression within the same individual and across siblings. Quantitative genetic modeling was performed to investigate the relative contribution of genetic and environmental influences.RESULTS: Individuals with endocrine-metabolic disorders had a significantly higher risk of depression, with odds ratios ranging from 1.43 (95% CI=1.30, 1.57) for Graves' disease to 3.48 (95% CI=3.25, 3.72) for type 2 diabetes. Increased risks extended to full and half siblings. These correlations were mainly explained by shared genetic influences for non-autoimmune conditions, and by nonshared environmental factors for autoimmune disorders, especially for type 1 diabetes.CONCLUSIONS: These findings provide phenotypic and etiological insights into the co-occurrence of depression and various endocrine-metabolic conditions, which could guide future research aiming at identifying pathophysiological mechanisms and intervention targets.
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| 28. |
- Nilsson, Per Anders, 1968-, et al.
(författare)
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Species integrity enhanced by a predation cost to hybrids in the wild
- 2017
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 13:7, s. 1-4
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Tidskriftsartikel (refereegranskat)abstract
- Species integrity can be challenged, and even eroded, if closely related species can hybridize and produce fertile offspring of comparable fitness to that of par- ental species. The maintenance of newly diverged or closely related species therefore hinges on the establishment and effectiveness of pre- and/or post- zygotic reproductive barriers. Ecological selection, including predation, is often presumed to contribute to reduced hybrid fitness, but field evidence for a predation cost to hybridization remains elusive. Here we provide proof-of- concept for predation on hybrids being a postzygotic barrier to gene flow in the wild. Cyprinid fishes commonly produce fertile, viable hybrid offspring and therefore make excellent study organisms to investigate ecological costs to hybrids. We electronically tagged two freshwater cyprinid fish species (roach Rutilus rutilus and bream Abramis brama) and their hybrids in 2005. Tagged fish were returned to their lake of origin, exposing them to natural predation risk from apex avian predators (great cormorant, Phalacrocorax carbo). Scanning for regurgitated tags under cormorant roosts 3–4 years later ident- ified cormorant-killed individual fish and allowed us to directly test for a predation cost to hybrids in the wild. Hybrid individuals were found significantly more susceptible to cormorant predation than individuals from either parental species. Such ecological selection against hybrids contributes to species integrity, and can enhance species diversification.
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| 29. |
- Petäjä, Tuukka, et al.
(författare)
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Overview : Integrative and Comprehensive Understanding on Polar Environments (iCUPE) - concept and initial results
- 2020
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 20:14, s. 8551-8592
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Tidskriftsartikel (refereegranskat)abstract
- The role of polar regions is increasing in terms of megatrends such as globalization, new transport routes, demography, and the use of natural resources with consequent effects on regional and transported pollutant concentrations. We set up the ERA-PLANET Strand 4 project iCUPE - integrative and Comprehensive Understanding on Polar Environments to provide novel insights and observational data on global grand challenges with an Arctic focus. We utilize an integrated approach combining in situ observations, satellite remote sensing Earth observations (EOs), and multi-scale modeling to synthesize data from comprehensive long-term measurements, intensive campaigns, and satellites to deliver data products, metrics, and indicators to stakeholders concerning the environmental status, availability, and extraction of natural resources in the polar areas. The iCUPE work consists of thematic state-of-the-art research and the provision of novel data in atmospheric pollution, local sources and transboundary transport, the characterization of arctic surfaces and their changes, an assessment of the concentrations and impacts of heavy metals and persistent organic pollutants and their cycling, the quantification of emissions from natural resource extraction, and the validation and optimization of satellite Earth observation (EO) data streams. In this paper we introduce the iCUPE project and summarize initial results arising out of the integration of comprehensive in situ observations, satellite remote sensing, and multi-scale modeling in the Arctic context.
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| 30. |
- Pärssinen, Varpu, et al.
(författare)
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Maladaptive migration behaviour in hybrids links to predator-mediated ecological selection
- 2020
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Ingår i: Journal of Animal Ecology. - : John Wiley & Sons. - 0021-8790 .- 1365-2656. ; 89:11, s. 2596-2604
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Tidskriftsartikel (refereegranskat)abstract
- Different migratory species have evolved distinct migratory characteristics that improve fitness in their particular ecological niches. However, when such species hybridize, migratory traits from parental species can combine maladaptively and cause hybrids to fall between parental fitness peaks, with potential consequences for hybrid viability and species integrity. Here, we take advantage of a natural cross-breeding incident to study migratory behaviour in naturally occurring hybrids as well as in their parental species and explore links between migratory traits and predation risk. To achieve this, we used electronic tags and passive telemetry to record detailed individual migration patterns (timing and number of migratory trips) in two common freshwater fish species, roachRutilus rutilus, common breamAbramis bramaas well as their hybrids. Next, we scanned for tags regurgitated by a key avian predator (great cormorantPhalacrocorax carbo) at nearby roosting sites, allowing us to directly link migratory behaviour to predation risk in the wild. We found that hybrid individuals showed a higher number of short, multi-trip movements between lake and stream habitats as compared to both parental species. The mean date of first lake departure differed between bream and roach by more than 10 days, while hybrids departed in two distinct peaks that overlapped with the parental species' averages. Moreover, the probability of cormorant predation increased with multi-trip movement frequency across species and was higher for hybrids. Our data provide novel insights into hybrid viability, with links to predator-mediated ecological selection. Increased exposure to predators via maladaptive migratory behaviour reduces hybrid survival and can thereby reinforce species integrity.
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| 31. |
- Saevik, Ase Bjorvatn, et al.
(författare)
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Altered biomarkers for cardiovascular disease and inflammation in autoimmune Addison's disease - a cross-sectional study
- 2023
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Ingår i: European Journal of Endocrinology. - : Bioscientifica. - 0804-4643 .- 1479-683X. ; 189:4, s. 438-447
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Increased prevalence of cardiovascular disease has been reported in autoimmune Addisons disease (AAD), but pathomechanisms are poorly understood.Design: Cross-sectional study.Methods: We compared serum levels of 177 cardiovascular and inflammatory biomarkers in 43 patients with AAD at >18-h glucocorticoid withdrawal and 43 matched controls, overall and stratified for sex. Biomarker levels were correlated with the frequency of adrenal crises and quality of life (QoL) by AddiQoL-30. Finally, we investigated changes in biomarker levels following 250 mu g tetracosactide injection in patients without residual adrenocortical function (RAF) to explore glucocorticoid-independent effects of high ACTH.Results: Nineteen biomarkers significantly differed between patients with AAD and controls; all but 1 (ST1A1) were higher in AAD. Eight biomarkers were significantly higher in female patients compared with controls (IL6, MCP1, GAL9, SPON2, DR4, RAGE, TNFRSF9, and PGF), but none differed between male patients and controls. Levels of RAGE correlated with the frequency of adrenal crises (r = 0.415, P = .006) and AddiQoL-30 scores (r = -0.347, P = .028) but not after correction for multiple testing. PDL2 and leptin significantly declined 60 min after injection of ACTH in AAD without RAF (-0.15 normalized protein expression [NPX], P = .0001, and -0.25 NPX, P = .0003, respectively).Conclusions: We show that cardiovascular and inflammatory biomarkers are altered in AAD compared with controls, particularly in women. RAGE might be a marker of disease severity in AAD, associated with more adrenal crises and reduced QoL. High ACTH reduced PDL2 and leptin levels in a glucocorticoid-independent manner but the overall effect on biomarker profiles was small.
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| 32. |
- Sævik, Åse Bjorvatn, et al.
(författare)
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Residual Corticosteroid Production in Autoimmune Addison Disease
- 2020
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - Washington : Oxford University Press. - 0021-972X .- 1945-7197. ; 105:7, s. 2430-2441
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Tidskriftsartikel (refereegranskat)abstract
- Context: Contrary to current dogma, growing evidence suggests that some patients with autoimmune Addison disease (AAD) produce corticosteroids even years after diagnosis.Objective: To determine frequencies and clinical features of residual corticosteroid production in patients with AAD.Design: Two-staged, cross-sectional clinical study in 17 centers (Norway, Sweden, and Germany). Residual glucocorticoid (GC) production was defined as quantifiable serum cortisol and 11-deoxycortisol and residual mineralocorticoid (MC) production as quantifiable serum aldosterone and corticosterone after > 18 hours of medication fasting. Corticosteroids were analyzed by liquid chromatography-tandem mass spectrometry. Clinical variables included frequency of adrenal crises and quality of life. Peak cortisol response was evaluated by a standard 250 µg cosyntropin test.Results: Fifty-eight (30.2%) of 192 patients had residual GC production, more common in men (n = 33; P < 0.002) and in shorter disease duration (median 6 [0-44] vs 13 [0-53] years; P < 0.001). Residual MC production was found in 26 (13.5%) patients and associated with shorter disease duration (median 5.5 [0.5-26.0] vs 13 [0-53] years; P < 0.004), lower fludrocortisone replacement dosage (median 0.075 [0.050-0.120] vs 0.100 [0.028-0.300] mg; P < 0.005), and higher plasma renin concentration (median 179 [22-915] vs 47.5 [0.6-658.0] mU/L; P < 0.001). There was no significant association between residual production and frequency of adrenal crises or quality of life. None had a normal cosyntropin response, but peak cortisol strongly correlated with unstimulated cortisol (r = 0.989; P < 0.001) and plasma adrenocorticotropic hormone (ACTH; r = -0.487; P < 0.001).Conclusion: In established AAD, one-third of the patients still produce GCs even decades after diagnosis. Residual production is more common in men and in patients with shorter disease duration but is not associated with adrenal crises or quality of life.
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| 33. |
- Schmale, Julia, et al.
(författare)
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Pan-Arctic seasonal cycles and long-term trends of aerosol properties from 10 observatories
- 2022
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 22:5, s. 3067-3096
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Tidskriftsartikel (refereegranskat)abstract
- Even though the Arctic is remote, aerosol properties observed there are strongly influenced by anthropogenic emissions from outside the Arctic. This is particularly true for the so-called Arctic haze season (January through April). In summer (June through September), when atmospheric transport patterns change, and precipitation is more frequent, local Arctic sources, i.e., natural sources of aerosols and precursors, play an important role. Over the last few decades, significant reductions in anthropogenic emissions have taken place. At the same time a large body of literature shows evidence that the Arctic is undergoing fundamental environmental changes due to climate forcing, leading to enhanced emissions by natural processes that may impact aerosol properties.In this study, we analyze 9 aerosol chemical species and 4 particle optical properties from 10 Arctic observatories (Alert, Kevo, Pallas, Summit, Thule, Tiksi, Barrow/Utqiaġvik, Villum, and Gruvebadet and Zeppelin Observatory – both at Ny-Ålesund Research Station) to understand changes in anthropogenic and natural aerosol contributions. Variables include equivalent black carbon, particulate sulfate, nitrate, ammonium, methanesulfonic acid, sodium, iron, calcium and potassium, as well as scattering and absorption coefficients, single scattering albedo and scattering Ångström exponent.First, annual cycles are investigated, which despite anthropogenic emission reductions still show the Arctic haze phenomenon. Second, long-term trends are studied using the Mann–Kendall Theil–Sen slope method. We find in total 41 significant trends over full station records, i.e., spanning more than a decade, compared to 26 significant decadal trends. The majority of significantly declining trends is from anthropogenic tracers and occurred during the haze period, driven by emission changes between 1990 and 2000. For the summer period, no uniform picture of trends has emerged. Twenty-six percent of trends, i.e., 19 out of 73, are significant, and of those 5 are positive and 14 are negative. Negative trends include not only anthropogenic tracers such as equivalent black carbon at Kevo, but also natural indicators such as methanesulfonic acid and non-sea-salt calcium at Alert. Positive trends are observed for sulfate at Gruvebadet.No clear evidence of a significant change in the natural aerosol contribution can be observed yet. However, testing the sensitivity of the Mann–Kendall Theil–Sen method, we find that monotonic changes of around 5 % yr−1 in an aerosol property are needed to detect a significant trend within one decade. This highlights that long-term efforts well beyond a decade are needed to capture smaller changes. It is particularly important to understand the ongoing natural changes in the Arctic, where interannual variability can be high, such as with forest fire emissions and their influence on the aerosol population.To investigate the climate-change-induced influence on the aerosol population and the resulting climate feedback, long-term observations of tracers more specific to natural sources are needed, as well as of particle microphysical properties such as size distributions, which can be used to identify changes in particle populations which are not well captured by mass-oriented methods such as bulk chemical composition.
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| 34. |
- Skov, Christian, et al.
(författare)
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A field evaluation of long-term effects of PIT tagging
- 2020
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 96:4, s. 1055-1059
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Tidskriftsartikel (refereegranskat)abstract
- Passive integrated transponder (PIT)-tagging is commonly used in behavioural studies of fish, although long-term evaluations of effects from tagging under natural conditions are scarce. We PIT-tagged common bream Abramis brama, European perch Perca fluviatilis, pike Esox lucius and roach Rutilus rutilus, released them in their lakes of origin and recaptured them after 103–3269 days. Overall, tagged fish did not differ in condition from non-tagged fish, except for small R. rutilus that had a lower length-specific body mass in one lake in 1 year. We conclude that PIT-tagging in general has negligible long-term effects on fish condition.
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| 35. |
- Skov, Christian, et al.
(författare)
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Biomanipulating streams : A supplementary tool in lake restoration
- 2019
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Ingår i: Hydrobiologia. - : Springer. - 0018-8158 .- 1573-5117. ; 829:1, s. 205-216
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Tidskriftsartikel (refereegranskat)abstract
- Removal of cyprinid fish is a widely used biomanipulation tool to transform turbid shallow eutrophic lakes in north temperate regions into a clear water state. We here evaluate the removal of cyprinids from streams as a supplement to lake fishing. Since cyprinids often aggregate in high densities in lake inlet/outlet streams during winter migration, removal of fish in this space-confined habitat may be cost-efficient as compared to fish removal in the lake habitat. In two consecutive years, we annually removed up to 35% of the dominant cyprinids from an inlet stream to a lake and argue that this could easily be increased with a more targeted fishing effort. Concurrently, we monitored species- and length-specific variation in migration propensity, to explore how this relates to efficient fish removal. Smaller planktivores generally had a much higher migratory propensity than larger benthivores. Hence, stream fishing specifically targets species and size groups that are less efficiently controlled with traditional lake fishing methods. As a rule of thumb, stream fishing is most efficient when water temperature is 2–6°C. Prior to implementing fish removals from streams, the potential evolutionary consequences of the targeted removal of migratory phenotypes should be considered.
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| 36. |
- Skov, Christian, et al.
(författare)
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Evaluation of PIT-tagging in cyprinids.
- 2005
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 67:5, s. 1195-1201
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Tidskriftsartikel (refereegranskat)abstract
- Laboratory and field experiments were used to investigate how different marking procedures, with 23 mm PIT (passive integrated transponders) – tags, affected mortality, body condition and tag expulsion in small roach Rutilus rutilus and rudd Scardinus erythrophthalmus (117 to 163 mm total length). In a laboratory experiment mortality was low (≤ 6%) and only occurred among fishes that had their incision closed with sutures. The latter also had a specific growth rate that tended to be lower than the fish tagged without sutures. The different marking procedures did not adversely affect the body condition of fishes either in the laboratory experiment (after 37 days) or in the field experiment (up to 369 days). No tag expulsions were observed among laboratory fishes PITtagged without sutures. Marking without the use of sutures to close the incision, appears to be the most appropriate PIT tagging procedure for small cyprinids.
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| 37. |
- Skov, Christian, et al.
(författare)
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Influences of environmental cues, migration history, and habitat familiarity on partial migration
- 2010
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 21:6, s. 1140-1146
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Tidskriftsartikel (refereegranskat)abstract
- The factors that drive partial migration in organisms are not fully understood. Roach (Rutilus rutilus), a freshwater fish, engage in partial migration where parts of populations switch between summer habitats in lakes and winter habitats in connected streams. To test if the partial migration trait is phenotypically plastic or has genetic components, we translocated roach from 2 populations with different opportunities for migration to a lake with migration opportunity, containing a local roach population. This enabled monitoring of partial migration of fish in 3 different situations: 1) previous opportunity for migration, migrating in a familiar environment (the local population); 2) previous opportunity for migration, migrating in an unfamiliar environment; and 3) no previous opportunity for seasonal migration, migrating in an unfamiliar environment. In addition, we evaluated the migration patterns of roach in the lake with migration opportunity where from group 2 fish were translocated. Directional migration in and out of the lakes was monitored using Passive Integrated Transponder technology. Translocated fish with previous migration opportunity showed migration patterns more similar to local fish than to their home lake population, and individuals translocated from the lake without migration opportunity migrated when given the opportunity, suggesting that partial migration is phenotypically plastic and triggered by lake-specific environmental cues. We found temperature to be a proximate cue for migration decisions. Individuals without previous migration opportunity migrated at a lower proportion and with different small-scale migration patterns, suggesting that also genetic components are involved in the expression of the partial migration trait.
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| 38. |
- Skov, Christian, et al.
(författare)
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Inter- and size-specific patterns of fish seasonal migration between a shallow lake and its streams
- 2008
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Ingår i: Ecology of Freshwater Fish. - : Wiley. - 0906-6691 .- 1600-0633. ; 17:3, s. 406-415
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in Undetermined This study used passive telemetry (passive integrated transponders) to evaluate winter migration in three species of cyprinids (roach (Rutilus rutilus (L.)), white bream (Blicca bjoerkna (L.)) and rudd (Scardinius erythrophthalmus (L.))) and their potential predators (pike (Esox lucius (L.)) and perch (Perca fluviatilis (L.))) between a shallow lake and its streams. Migration patterns were investigated from October to June, and a substantial part of the roach (40%) and white bream (55%) populations tagged in the lake during autumn migrated during winter into the streams, whereas only very few piscivores (< 2%) migrated. In contrast to roach and white bream, only few rudd (< 6%) migrated, which is likely a consequence of different overwintering strategies, e.g., rudd overwintering in shallow highly structured habitats. Small rudd migrated more than larger rudd, whereas there were no size-differentiated migration patterns for roach or white bream. Migration of the cyprinid fishes was generally initiated in late October and ended in May, and specific synchronised bursts of migration were observed in December, January and April, suggesting that migration is triggered by one or more proximate environmental cues. The cyprinid fishes generally entered the streams in late afternoon or in the morning, depending on season, but overall migration patterns varied between the three streams. We suggest and discuss that our results have great implications for lake management as well as for the interpretation of seasonal trophic dynamics in shallow lakes.
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| 39. |
- Skov, Christian, et al.
(författare)
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Migration confers survival benefits against avian predators for partially migratory freshwater fish
- 2013
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 9:2, s. 20121178-
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Tidskriftsartikel (refereegranskat)abstract
- The importance of predation risk in shaping patterns of animal migration is not well studied, mostly owing to difficulties in accurately quantifying predation risk for migratory versus resident individuals. Here, we present data from an extensive field study, which shows that migration in a freshwater fish (roach, Rutilus rutilus) that commonly migrates from lakes to streams during winter confers a significant survival benefit with respect to bird (cormorant, Phalacrocorax carbo spp.) predation. We tagged over 2000 individual fish in two Scandinavian lakes over 4 years and monitored migratory behaviour using passive telemetry. Next, we calculated the predation vulnerability of fish with differing migration strategies, by recovering data from passive integrated transponder tags of fish eaten by cormorants at communal roosts close to the lakes. We show that fish can reduce their predation risk from cormorants by migrating into streams, and that probability of being preyed upon by cormorants is positively related to the time individuals spend in the lake during winter. Our data add to the growing body of evidence that highlights the importance of predation for migratory dynamics, and, to our knowledge, is one of the first studies to directly quantify a predator avoidance benefit to migrants in the field.
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| 40. |
- Skov, Christian, et al.
(författare)
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Sizing up your enemy : individual predation vulnerability predicts migratory probability
- 2011
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 278, s. 1414-1418
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Tidskriftsartikel (refereegranskat)abstract
- Partial migration, in which a fraction of a population migrate and the rest remain resident, occurs in anextensive range of species and can have powerful ecological consequences. The question of what drivesdifferences in individual migratory tendency is a contentious one. It has been shown that the timing ofpartial migration is based upon a trade-off between seasonal fluctuations in predation risk and growthpotential. Phenotypic variation in either individual predation risk or growth potential should thus mediatethe strength of the trade-off and ultimately predict patterns of partial migration at the individual level (i.e.which individuals migrate and which remain resident). We provide cross-population empirical support forthe importance of one component of this model—individual predation risk—in predicting partialmigration in wild populations of bream Abramis brama, a freshwater fish. Smaller, high-risk individualsmigrate with a higher probability than larger, low-risk individuals, and we suggest that predation riskmaintains size-dependent partial migration in this system.
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| 41. |
- Skov, Jakob, et al.
(författare)
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Co-aggregation and heritability of organ-specific autoimmunity : a population-based twin study
- 2020
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Ingår i: European Journal of Endocrinology. - : Bioscientifica. - 0804-4643 .- 1479-683X. ; 182:5, s. 473-480
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Co-aggregation of autoimmune diseases is common, suggesting partly shared etiologies. Genetic factors are believed to be important, but objective measures of environ mental vs heritable influences on co-aggregation are absent. With a novel approach to twin studies, we aimed at estimating heritability and genetic overlap in seven organspecific autoimmune diseases.Design: Prospective twin cohort study.Methods: We used a cohort of 110 814 twins to examine co-aggregation and heritability of Hashimoto's thyroiditis, atrophic gastritis, celiac disease, Graves' disease, type 1 diabetes, vitiligo and Addison's disease. Hazard ratios (HR) were calculated for twins developing the same or different disease as compared to their co-twin. The differences between monozygotic and dizygotic twin pairs were used to estimate the genetic influence on co-aggregation. Heritability for individual disorders was calculated using structural equational modeling adjusting for censoring and truncation of data.Results: Co-aggregation was more pronounced in monozygotic twins (media n HR: 3.2, range: 2.2-9.2) than in dizygotic twins (median HR: 2.4, range: 1.1-10.0). Heritability was moderate for atrophic gastritis (0.38, 95% CI: 0.23-0.53) but high for all other diseases, ranging from 0.60 (95% CI: 0.49-0. 71) for Graves' disease to 0.97 (95% CI: 0.91- 1.00) for Addison's disease.Conclusions: Overall, co-aggregation was more pronounced in monozygotic than in dizygotic twins, suggesting that disease overlap is largely attributable to genetic factors. Co-aggregation was common, and twins faced up to a ten-fold risk of developing diseases not present in their co-twin. Our results validate and refine previous heritability estimates based on smaller twin cohorts.
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| 42. |
- Skov, Jakob
(författare)
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Epidemiological studies on comorbidity, heritability and co-aggregation in organ-specific autoimmune diseases
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Autoimmunity is caused by loss of tolerance, whereby the immune system fails to distinguish self from non-self. The autoimmune panorama entails more than 100 diseases that collectively affect close to 5% of the total population, with a higher prevalence in women than in men. Depending on which tissues are targeted, autoimmunity is classified as organ-specific or systemic. For unknown reasons, organ-specific autoimmunity often targets the endocrine system, leading to organ failure and lifelong need of hormone replacement. Most autoimmune diseases show familial clustering, but co-aggregation of different disorders in family members, and co-occurrence of multiple diseases in a single individual, is also common. This points to shared etiologies in autoimmunity. Twin studies can help explain to what extent genetic and environmental influences contribute to differences in traits, and can thus provide a framework for genetic studies. In autoimmunity, twin studies have helped explain genetic contributions (heritability) for some diseases, but for many they are still lacking. In other scientific fields, twin studies have also been used to shed light on disease overlap, but no attempts of explaining clustering of autoimmunity using twins have been published. In this thesis we explore different aspects of organ-specific autoimmunity. In Study I, we use the Swedish Twin Registry to demonstrate that the heritability for Addison’s disease is very high, making it suitable for further genetic studies. In Study II we use national health registries to explore cardiovascular morbidity for Addison’s disease, and show that women are at increased risk of cardiac events. We also demonstrate a dose-dependent correlation between adrenal hormone replacement-therapy and risk of cardiovascular disease. Study III addresses genetic versus non-genetic components to clustering in seven autoimmune diseases, and we find evidence of genetic factors explaining co-aggregation. In Study III we also validate previous estimates of heritability in autoimmunity by using a larger cohort of twins than ever before used. In Study IV, we take a closer look at Hashimoto’s thyroiditis and Graves’ disease, again using twins. Results imply that they are distantly related diseases, in contrast with current dogma. We also find that heritability is higher in men than in women, most notably for Hashimoto’s thyroiditis. This could mean that the mechanisms leading to disease differ between the sexes.
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| 43. |
- Skov, Jakob, et al.
(författare)
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Limited Genetic Overlap Between Overt Hashimoto's Thyroiditis and Graves' Disease in Twins : A Population-based Study
- 2021
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : Endocrine Society. - 0021-972X .- 1945-7197. ; 106:4, s. 1101-1110
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Tidskriftsartikel (refereegranskat)abstract
- Context: Hashimoto's thyroiditis (HT) and Graves' disease (GD) are known to coaggregate in families, but the magnitude and nature of a shared etiology is unknown.Objectives: To estimate the shared genetic influence on overt HT and GD and to examine if the heritability differs between men and women. Design, setting, and patients: We used national health registries to identify cases of HT and GD in a cohort of 110 814 Swedish twins. By comparing intra-class and cross-twin cross-trait correlations in dizygotic and monozygotic twins, we calculated heritability and the proportions thereof shared between the diseases. Univariate estimates of heritability were calculated by sex.Results: The heritability for HT and GD was 65% (95% CI, 61-70) and 63% (95% CI, 55-72), respectively. The genetic correlation was 0.35 (95% CI, 0.20-0.50) and shared genetic effects accounted for 8% of the variance for both HT and GD. Univariate heritability was significantly higher in men than in women for HT (90% vs 60%, P < 0.001) but not for GD (79% vs 63%, P = 0.085).Conclusions: From a genetic perspective, HT and GD appear to be only modestly related diseases. Hence, the term "autoimmune thyroid disease," used to cluster these disorders, may have limited validity in a genetic context. Moreover, the mechanisms contributing to HT are partly different for the sexes, with genetic components more important in men.
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| 44. |
- Wedge, Eileen, et al.
(författare)
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Allogeneic Hematopoietic Stem Cell Transplantation for Chronic Myelomonocytic Leukemia : Clinical and Molecular Genetic Prognostic Factors in a Nordic Population
- 2021
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Ingår i: Transplantation and Cellular Therapy. - : Elsevier. - 2666-6375 .- 2666-6367. ; 27:12, s. 991.e1-991.e9
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Tidskriftsartikel (refereegranskat)abstract
- Chronic myelomonocytic leukemia (CMML) is an aggressive disease in which survival after allogeneic hematopoietic stem cell transplantation (HCT) remains relatively poor. An assessment of prognostic factors is an important part of treatment decision making and has the potential to be greatly improved by the inclusion of molecular genetics. However, there is a significant knowledge gap in the interpretation of mutational patterns. This study aimed to describe outcomes of allogeneic HCT in patients with CMML in relation to clinical and molecular genetic risk factors. This retrospective study included 64 patients with CMML who underwent allogeneic HCT between 2008 and 2018, with a median follow-up of 5.4 years. Next-generation sequencing using targeted myeloid panels was carried out on saved material from 51 patients from the time of transplantation. Kaplan-Meier and Cox regression were used for analysis of overall survival (OS), and cumulative incidence with competing risks and Fine and Gray models were used for analysis of relapse and nonrelapse mortality (NRM). Mutations were detected in 48 patients (94%), indicating high levels of minimal residual disease (MRD) positivity at transplantation, even among those in complete remission (CR) (n = 14), 86% of whom had detectable mutations. The most frequently mutated genes were ASXL1 (37%), TET2 (37%), RUNX1 (33%), SRSF2 (26%), and NRAS (20%). Risk stratification using the CMML-specific Prognostic Scoring System molecular score (CPSS-Mol) resulted in 45% of patients moving to a higher risk-group compared with risk stratification using the CPSS. High leucocyte count (>= 13 x 10(9)/L), transfusion requirement, and previous intensive chemotherapy were associated with higher incidence of relapse. Being in CR was not linked to better outcomes. Neither ASXL1 nor RUNX1 mutation was associated with a difference in OS, relapse, or NRM, despite being high risk in the nontransplantation setting. TET2 mutations were associated with a significantly higher 3-year OS (73% versus 40%; P =.039). Achieving MRD-negative CR was rare in this CMML cohort, which may explain why we did not observe better outcomes for those in CR. This merits further investigation. Our analyses suggest that the negative impact of ASXL1 and RUNX1 mutations can be overcome by allogeneic HCT; however, risk stratification is complex in CMML and requires larger cohorts and multivariate models, presenting an ongoing challenge in this rare disease.
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| 45. |
- Åkerman, Anna-Karin, et al.
(författare)
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Plasma-Metanephrines in Patients with Autoimmune Addison's Disease with and without Residual Adrenocortical Function
- 2023
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Ingår i: Journal of Clinical Medicine. - : MDPI. - 2077-0383. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Residual adrenocortical function, RAF, has recently been demonstrated in one-third of patients with autoimmune Addison's disease (AAD). Here, we set out to explore any influence of RAF on the levels of plasma metanephrines and any changes following stimulation with cosyntropin.METHODS: We included 50 patients with verified RAF and 20 patients without RAF who served as controls upon cosyntropin stimulation testing. The patients had abstained from glucocorticoid and fludrocortisone replacement > 18 and 24 h, respectively, prior to morning blood sampling. The samples were obtained before and 30 and 60 min after cosyntropin stimulation and analyzed for serum cortisol, plasma metanephrine (MN), and normetanephrine (NMN) by liquid-chromatography tandem-mass pectrometry (LC-MS/MS).RESULTS: Among the 70 patients with AAD, MN was detectable in 33%, 25%, and 26% at baseline, 30 min, and 60 min after cosyntropin stimulation, respectively. Patients with RAF were more likely to have detectable MN at baseline (p = 0.035) and at the time of 60 min (p = 0.048) compared to patients without RAF. There was a positive correlation between detectable MN and the level of cortisol at all time points (p = 0.02, p = 0.04, p < 0.001). No difference was noted for NMN levels, which remained within the normal reference ranges.CONCLUSION: Even very small amounts of endogenous cortisol production affect MN levels in patients with AAD.
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