60 research outputs found
Mineral, fluid and thermal evolution in veins from late orogenic coal basins of the Cantabrian Zone (Variscan, NW Spain)
The detailed study of syn-tectonic mineral veins and textural features of fluid inclusions is a useful approach for reconstructing the fluid and thermal evolution in diagenetic and very low-grade metamorphism environments. Here, mineralised fissures within the clastic sedimentary rocks of the Ciñera-Matallana and Sabero Stephanian pull-apart coal basins (Cantabrian Zone, Variscan of NW Spain) are investigated. These bedding perpendicular fissures (cm-wide) formed in sandstones synchronous with folding and faulting during bedding-parallel slip. Three stages of infilling and mineral growth are recognised within the veins, reflecting different fracture-opening events under different fluid, thermal and tectonic regimes at hydrostatic pressure conditions: Stage 1 was related to the temperature rise during burial before thermal peak conditions were attained (during Permian times). Euhedral quartz crystallised from a heterogeneously trapped, immiscible H2O-CH4 -CO2 (± NaCl) fluid mixture. P-T conditions evolved from 73 °- 110 °C and 15-56 MPa to 87 °-129 °C and 10-27 MPa. At a late stage of quartz growth saddle dolomite precipitated. Materials for mineral precipitation were derived locally from the detrital fraction within the Stephanian rocks,and transported into solution by advection of large volumes of gas (CH4 -CO2) and water formed in response to progressive maturation of the coal. Stage 2 also occurred under burial conditions, with lower temperature diagenetic dissolution-precipitation reactions controlling mineral growth. Brittle reactivation of veins caused microcracking of the large quartz crystals and extensive dedolomitisation. Ferroan blocky calcite precipitated at 60 ° to 100 °C from a H2O-NaCl-CaCl2 -CH4 fluid with total salinities from 20.5 to 31.9 eq.wt%, also preserved as secondary inclusions in the vein quartz. This fracture re-opening and fluid flow event was related to the infiltration of marine water during Cretaceous tectonic subsidence, subsequently modified and expelled during late tectonic reactivation (Alpine Orogeny). Stage 3 was linked with uplift and exhumation of the basin fill. Late calcite and authigenic kaolinite formed in response to low-temperature diagenetic and weathering reactions of the Stephanian rocks. Mineral precipitation was controlled by a constant supply of meteoric water (T <50 °C), that circulated preferentially along fault structures reaching the deeper parts of the stratigraphic section. Shortly after the Stage 1 of vein evolution,diorite sills were emplaced into the basinal sequences and small veins containing quartz and kaolinite formed within some of these intrusives.The hydrothermal quartz also crystallised from an immiscible H2O-CH4 -CO2 (± NaCl) fluid at 164 °-296 °C and 3-48 MPa,and is considered to be the product of extensive mineral alteration as the cooling magma intruded along coal seams. A variety of thermally re-equilibrated fluid inclusions are reported in fissure quartz within the clastic rocks. Five textural types of re-equilibration were recognised in progressive order of inclusion modification: scalloped, hairy, annular-ring shaped, haloes and decrepitation clusters. These textures resulted from a combination of brittle fracturing and dissolution and re-precipitation of quartz, with preferential loss of water. Decrepitation of fluid inclusions in vein quartz throughout the entire basin reflects the wide extent of the thermal peak. Short-lived, high temperatures are related to the intrusion and alteration of the diorites in the basin, which further enhanced degassing and dehydration of the coal. The generated fluid probably circulated by advection through the already formed fissure network. Keywords: fluid-rock interaction, coal basins, veins, quartz, fluid inclusions, re-equilibration textures, thermal peak and heat transmission
Investigating the frequency of triploid Atlantic salmon in wild Norwegian and Russian populations
Fish may display variations in ploidy, including three sets of chromosomes, known as triploidy. A recent study revealed a frequency of ~ 2% spontaneous (i.e., non-intentional) triploidy in domesticated Atlantic salmon produced in Norwegian aquaculture in the period 2007–2014. In contrast, the frequency of triploidy in wild salmon populations has not been studied thus far, and in wild populations of other organisms, it has been very rarely studied. In population genetic data sets, individuals that potentially display chromosome abnormalities, such as triploids with three alleles, are typically excluded on the premise that they may reflect polluted or otherwise compromised samples. Here, we critically re-investigated the microsatellite genetic profile of ~ 6000 wild Atlantic salmon sampled from 80 rivers in Norway and Russia, to investigate the frequency of triploid individuals in wild salmon populations for the first time.publishedVersio
Introgression of domesticated salmon changes life history and phenology of a wild salmon population
The release of domesticated conspecifics into the natural environment, whether deliberate or accidental, has the potential to alter the genetic integrity and evolutionary trajectory of wild populations. This widespread challenge is of particular concern for wild Atlantic salmon. By investigating phenotypic differences between the offspring of domesticated, hybrid, and wild Atlantic salmon released into the natural environment, earlier studies have documented the short-term consequences of introgression from domesticated fish into wild salmon populations. However, few studies have investigated the joined product of introgression and natural selection after several generations. Here, we investigated the phenotypic response of an Atlantic salmon population that has been subjected to an average of 24% genetic admixture by domesticated conspecifics escaping from fish farms over three decades (approximately 6–7 generations). Individual levels of admixture were positively correlated with increased size at the smolt and adult stages for both sexes, a decrease in the age of male smolts, and a decrease in the age at maturity for males. These life history changes are presumably the consequence of the well-documented directional selection for increased growth in domesticated salmon and are likely maladaptive. However, the most novel result of this study is that admixture was positively linked with delayed date of return to the river, with highly admixed fish arriving up to 26 days later than nonadmixed fish. Potentially, this phenological change provides admixed individuals with a survival advantage in the later phase of the life cycle as it reduces their period of exposure to selection through rod and line angling. We, therefore, conclude that while gene flow from domesticated conspecifics changes life history and phenological traits of wild Atlantic salmon populations, most of which are likely to be maladaptive, when pressured by additional anthropogenic challenges, some changes may confer a fitness advantage for a short part of the life cycle.publishedVersio
Levels of Physical Activity at Age 10 Years and Brain Morphology Changes from Ages 10 to 14 Years
Importance: Physical activity may promote healthy brain development in children, but previous research was predominantly cross-sectional and included small samples, providing limited knowledge. Objective:To investigate the longitudinal associations of physical activity with brain morphology changes. Design, Setting, and Participants: A 4-year longitudinal population-based cohort study in Rotterdam, the Netherlands, embedded in Generation R, a cohort from fetal life onward. From the women enrolled during pregnancy, children who had repeated measures of brain structure at ages 10 (range 8 to 12) years and 14 (range 13 to 15) years were included. Data were collected from March 2013 to November 2015 (baseline) and from October 2016 to January 2020 (follow-up). Data were analyzed from April to December 2022. Exposure: At age 10 years, both the child and their primary caregiver reported the child's levels of physical activity with regard to sport participation, outdoor play, and total physical activity. Primary analyses were based on an average multi-informant report. Main outcomes and measures: Brain morphology was quantified by magnetic resonance imaging. Hypothesized regions of interest were the bilateral amygdala and hippocampal volumes. Global brain measures were studied to test the specificity of the hypothesis. Results: Data were available for 1088 children (566 girls [52%]; 693 [64%] Dutch). Their mean (SD) age at baseline was 10.1 (0.6) years. For amygdala volume change, positive associations with multi-informant reports of total physical activity (β = 2.6; 95% CI, 0.3-4.9) were found. Total physical activity was associated with hippocampal volume increases only when reported by the child (β = 3.1; 95% CI, 0.4-5.8). No robust associations with global brain measures were found. Conclusions and relevance: In this cohort study of 1088 children, more physical activity at 10 years was consistently associated with an increase in amygdala volume in children aged 10 to 14 years. Physical activity and increases in hippocampal volume were found using child reports of physical activity only. These findings suggest physical activity in late childhood was prospectively associated with volumetric changes in specific subcortical structures, but not to global brain development, from late childhood to early adolescence. These findings may inform the design of future public health interventions to best facilitate neurodevelopment with physical activity..</p
Genetic study reveals local differentiation persisting in the face of high connectivity and a genomic inversion likely linked with sexual antagonism in a common marine fish
Sustainable harvest of wild populations requires knowledge of the underlying population structure. The focus of this study is on goldsinny wrasse (Ctenolabrus rupestris), a small marine fish inhabiting coastal waters of the north-eastern Atlantic. This species is caught in large numbers to serve as cleaner fish in salmonid aquaculture. We genotyped 2073 goldsinny wrasse from 43 sites along the Scandinavian coastline with 143 SNPs. Seven of the SNPs were linked and likely reside within a large genomic inversion dominated by one haplotype. The heterokaryotype of the putative inversion displayed sex-specific growth patterns, potentially resolving sexual antagonism for this trait. The unlinked 134 SNPs showed modest isolation-by-distance with samples from the northernmost locations showing highest divergence, whereas sites farther south were much more interconnected. Genetic divergence (FST) was highly variable among sites within regions, suggesting a varying degree of connectivity and local divergence. We conclude that despite a high degree of gene-flow mediated through pelagic dispersal in early life stages, regional and some local population structure remains due to limited adult movement in addition to other unidentified factors. Consequently, the species might be more vulnerable to local disturbances than previously anticipated.publishedVersio
Development of supermale and all-male Atlantic salmon to research the vgll3 allele - puberty link
Farmed Atlantic salmon are one of the most economically significant global aquaculture products. Early sexual maturation of farmed males represents a significant challenge to this industry and has been linked with the vgll3 genotype. However, tools to aid research of this topic, such as all-male and clonal fish, are still lacking. The present 6-year study examined if all-male production is possible in Atlantic salmon, a species with heteromorphic sex chromosomes (males being XY, females XX), and if all-male fish can be applied to further explore the vgll3 contribution on the likelihood of early maturation.publishedVersio
The influence of vgll3 genotypes on sea age at maturity is altered in farmed mowi strain Atlantic salmon
Background:
In Atlantic salmon in the wild, age at maturity is strongly influenced by the vgll3 locus. Under farming conditions, light, temperature and feeding regimes are known significantly advance or delay age at maturity. However, the potential influence of the vgll3 locus on the maturation of salmon reared under farming conditions has been rarely investigated, especially in females.
Results:
Here, we reared domesticated salmon (mowi strain) with different vgll3 genotypes under standard farming conditions until they matured at either one, two or more than two sea winters. Interestingly, and in contrast to previous findings in the wild, we were not able to identify a link between vgll3 and age at maturity in females when reared under farming conditions. For males however, we found that the probability of delaying maturation from one to two sea winters was significantly lower in fish homozygous for the early allele compared to homozygous fish for the late allele, while the probability for heterozygous fish was intermediate. These data also contrast to previous findings in the wild where the early allele has been reported as dominant. However, we found that the probability of males delaying maturation from two to three sea winters was regulated in the same manner as the wild.
Conclusions:
Collectively, our data suggest that increased growth rates in mowi salmon, caused by high feed intake and artificial light and temperature regimes together with other possible genetic/epigenetic components, may significantly influence the impact that the vgll3 locus has on age at maturity, especially in females. In turn, our results show that the vgll3 locus can only to a large extent be used in selective breeding to control age at maturation in mowi males. In summary, we here show that in contrast to the situation in wild salmon, under farming conditions vgll3 does not seem to influence age at maturity in mowi females whereas in mowi males, maturing as one or two sea winters it alters the early allele effect from dominant to intermediatepublishedVersio
Effectiveness of Exercise on Fatigue and Sleep Quality in Fibromyalgia: A Systematic Review and Meta-analysis of Randomized Trials
Objectives: To determine the effects of exercise on fatigue and sleep quality in fibromyalgia (primary aim) and to identify which type of exercise
is the most effective in achieving these outcomes (secondary aim).
Data Sources: PubMed and Web of Science were searched from inception until October 18, 2018.
Study Selection: Eligible studies contained information on population (fibromyalgia), intervention (exercise), and outcomes (fatigue or sleep).
Randomized controlled trials (RCT) testing the effectiveness of exercise compared with usual care and randomized trials (RT) comparing the
effectiveness of 2 different exercise interventions were included for the primary and secondary aims of the present review, respectively. Two
independent researchers performed the search, screening, and final eligibility of the articles. Of 696 studies identified, 17 RCTs (nZ1003) were
included for fatigue and 12 RCTs (nZ731) for sleep. Furthermore, 21 RTs compared the effectiveness of different exercise interventions (nZ1254).
Data Extraction: Two independent researchers extracted the key information from each eligible study.
Data Synthesis: Separate random-effect meta-analyses were performed to examine the effects from RCTs and from RTs (primary and secondary
aims). Standardized mean differences (SMD) effect sizes were calculated using Hedges’ adjusted g. Effect sizes of 0.2, 0.4, and 0.8 were considered
small, moderate, and large. Compared with usual care, exercise had moderate effects on fatigue and a small effect on sleep quality (SMD, e0.47; 95%
confidence interval [CI], e0.67 to e0.27; P<.001 and SMD, e0.17; 95% CI, e0.32 to e0.01; PZ.04). RTs in which fatigue was the primary outcome
were the most beneficial for lowering fatigue. Additionally, meditative exercise programs were the most effective for improving sleep quality.
Conclusions: Exercise is moderately effective for lowering fatigue and has small effects on enhancing sleep quality in fibromyalgia. Meditative
exercise programs may be considered for improving sleep quality in fibromyalgi
Atlantic salmon populations reveal adaptive divergence of immune related genes - A duplicated genome under selection
Comparison of anadromous and landlocked Atlantic salmon genomes reveals signatures of parallel and relaxed selection across the Northern Hemisphere
Most Atlantic salmon (Salmo salarL.) populations follow an anadromous life cycle, spending early life in freshwater, migrating to the sea for feeding, and returning to rivers to spawn. At the end of the last ice age similar to 10,000 years ago, several populations of Atlantic salmon became landlocked. Comparing their genomes to their anadromous counterparts can help identify genetic variation related to either freshwater residency or anadromy. The objective of this study was to identify consistently divergent loci between anadromous and landlocked Atlantic salmon strains throughout their geographical distribution, with the long-term aim of identifying traits relevant for salmon aquaculture, including fresh and seawater growth, omega-3 metabolism, smoltification, and disease resistance. We used a Pool-seq approach (n = 10-40 individuals per population) to sequence the genomes of twelve anadromous and six landlocked Atlantic salmon populations covering a large part of the Northern Hemisphere and conducted a genomewide association study to identify genomic regions having been under different selection pressure in landlocked and anadromous strains. A total of 28 genomic regions were identified and includedcadm1on Chr 13 andppargc1aon Chr 18. Seven of the regions additionally displayed consistently reduced heterozygosity in fish obtained from landlocked populations, including the genes gpr132, cdca4, and sertad2 on Chr 15. We also found 16 regions, includingigf1on Chr 17, which consistently display reduced heterozygosity in the anadromous populations compared to the freshwater populations, indicating relaxed selection on traits associated with anadromy in landlocked salmon. In conclusion, we have identified 37 regions which may harbor genetic variation relevant for improving fish welfare and quality in the salmon farming industry and for understanding life-history traits in fish.Peer reviewe
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