Academic literature on the topic 'Fin rays'

Understanding spatial patterns in population demographics and the principal natal environments supporting riverine fish populations are important for fisheries management. Although the black basses are among the most popular groups of game fishes in North America, relatively little information exists regarding demographics and environmental history of spotted bass Micropterus punctulatus in riverine environments. Fin ray microchemistry was used to identify natal environment and age estimates from sectioned fin rays used to estimate growth and mortality rates for spotted bass in Smithland pool of the Ohio River and three tributaries. Spotted bass were collected from 2014-2016 in headwater reaches of tributaries using electrofishing, angling, and a seine net, while electrofishing was used exclusively in the Ohio River and lower tributary reaches. Spotted bass in the Ohio River generally lived longer and grew larger than conspecifics in tributaries, although mortality rates were not definitively different. Differences in water Sr:Ca and Ba:Ca among the Ohio River and tributaries were reflected in fin rays from age-0 and age-1 fish. Eighteen percent of spotted bass ≥ age-2 captured in the Ohio River originated in tributaries, whereas 15% captured in tributaries originated in the Ohio River. Although most fish remained in their natal environment, small tributaries can be a supplemental recruitment source for spotted bass populations and fisheries in large rivers. This study highlights the utility of fin rays for microchemical analysis and age estimation of spotted bass.

This thesis aims to help sailboat owners to decide a preferable NACA profile. A CFD comparison in terms of drag and lift coefficients between two NACA profiles have been applied on a typical fin keel. Each profile has been computed with different angles of attack to investigate the impact of small direction changes. ANSYS Fluent 13.0 is used to model the flow according to RANS k-epsilon model. The conclusion is that NACA65 series gives lower drag while NACA64 series gives higher lift.<br>Syftet med det här examensarbetet är att undersöka skillnaderna för olika NACA-kölprofiler med avseende på tryckkoefficienter Arbetet strävar även efter att ge båtägare en tydligare bild av en fördelaktig NACA-profil. Varje kölprofil har beräknats med olika anfallsvinklar för att undersöka effekten av små vinkeländringar. ANSYS Fluent 13.0 har använts för att modellera flödet enligt k-epsilon-modellen. Slutsatsen är NACA65-serien ger en lägre motståndskoefficient medan NACA64-serien ger en högre lyftkoefficient.

This dissertation is about manipulating equipments using Fin Ray Effect ®. The model of manipulator, using this principle, was created for description of the manipulator movement. The measurement was done with this model. After result evaluation the improvement of model was proposed. There were also proposed technical applications where this type of manipulation could be used.

Knowledge of environmental history is important for the management and conservation of fish populations. Multiple methods to tag or mark fish have been developed (e.g., radio transmitters, coded wire tags, PIT tags, genetic markers), however, each of these methods has limitations. Naturally occurring and artificial chemical markers in otoliths have recently been used to determine natal origins and environmental history of fishes in both marine and freshwater environments and are not subject to the shortcomings of conventional tagging methods. However, few studies have evaluated the application of fish fin rays as a non-lethal alternative to fish otoliths as a recorder of individual fish environmental history. Therefore, I evaluated the application of artificial and naturally occurring chemical markers in fish fin rays as tracers of individual environmental histories. Specifically, I sought to determine 1) if age-0 lake sturgeon pectoral fin rays could be marked by immersion in strontium carbonate (SrCO3) enriched with the stable isotope 86Sr (86SrCO3), 2) whether natural differences in otolith and fin spine chemistry are present in catfish species collected from the Mississippi River basin, and 3) whether natural differences in fin ray chemistry are present in smallmouth bass from different rivers and streams in northern Illinois. Results from the first objective indicated that age-0 lake sturgeon were marked with 83% success when reared in water enriched with 100 µg/L of 86SrCO3, compared to control fish, and mark retention was maintained for at least 120 d following the labeling period. Results of the second objective indicated that both catfish otolith Sr:Ca, δ18O, and δ13C and fin spine Sr:Ca differed among sites, reflecting geographic differences in water chemistry at source locations. Both structures classified fish to their environment of capture with a high degree of accuracy, except in the Middle and Lower Mississippi Rivers where many recent immigrants appeared to be present. Similarly, smallmouth bass fin ray core Sr:Ca differed among sites, reflecting previously documented differences in water chemistry among streams and rivers in northern Illinois. Classification accuracy of smallmouth bass to their environment of capture based on fin ray Sr:Ca was variable, as some rivers had similar water chemistry signatures. The use of artificial chemical marks in fin rays will be useful when marking small fish that may not respond well to physical tags, when non-lethal recovery is desirable, and to distinguish between multiple batches of stocked fish (i.e. to evaluate factors such as stocking location and timing, fish size, and when fish may become interspersed into the existing population). Natural chemical signatures in pectoral fin rays or fin spines may provide a non-lethal alternative to otoliths for gathering information on environmental history (e.g. stock mixing, recruitment sources) of smallmouth bass and catfishes, consistent with recent demonstrations of this technique's effectiveness in other fish species. Ultimately, the use of artificial and naturally occurring chemical marks in fish fin rays provides a non-lethal alternative method to evaluate the environmental history of all life stages of fish

Zebrafish have the capability to regenerate their fins after injury. Previous studies from our laboratory showed that fin regeneration triggers the re-expression of genes involved in the hedgehog (hh) signaling pathway. One member of the hh family, sonic hedgehog (shh) was suggested to regulate bone patterning based on its expgression pattern and functional analysis. Another member of the hh family, Indian hedgehog (ihha) is expressed in the differentiating scleroblasts, the bone-matrix releasing cells, of each fin ray, and may have a more direct role on bone formation based on its expression pattern and known function in other vertebrates. The present study is aimed at investigating the role of hh signalling in patterning the fin ray regenerate and more specifically its role in ray branching morphogenesis. In a first approach, we used the zebrafish 2.2shh:gfp:ABC transgenic line, in which GFP expression recapitulates the endogenous expression of shh, to ablate the shh-expressing cells using a laser beam. Results show that such ablation leads to a delay of ray bifurcation suggesting that the shh-expressing cells play an important role in branching morphogenesis. In a second approach, we cloned the zebrafish hedgehog interacting protein (hip), a hedgehog antagonist, to investigate the effects of its overexpression on ray patterning. Analysis of hip expression during fin regeneration suggests its involvement in limiting hh signaling on the lateral sides of the dermal bones and in their medial region during branching morphogenesis. Overexpression of hip via in vivo cell transfection in the regenerating fin causes a branching delay, possibly as a result of the altered expression of patched1, the hh receptor and type X collagen, a component of the fin ray. These results suggest that hh signaling is involved in patterning the ray branching during zebrafish fin regeneration. Based on the distinct role of shh and ihha suggested by studies in other systems, ihha may be more involved in the scleroblast proliferation and differentiation, and shh is likely to be responsible to pattern the bone formation by directing the site of scleroblast differentiation or possibly mediating scleroblast migration.

In der Arbeit haben wir die Grenzen der weit verbreiteten tomographischen Rekonstruktion von 3D-Proben mittels Transmissionsröntgenmikroskopie charakterisiert. Wir zeigen, dass die 3D-Auflösung mit diesem Ansatz durch die Schärfentiefe begrenzt ist. Zur Untersuchung von Alternativen führten wir Simulationen zur Bildentstehung in einem konfokalen Röntgenmikroskop und einem FIB-SXM durch. Wir zeigen, dass FIB-SXM ein vielversprechender Ansatz ist, der eine isotrope 3D-Aulösung um die 10 nm erreichen kann und zusätzlich ein drastisch verbessertes Signal-Rausch-Verhältnis bieten könnte. Wir stellen auch eine neue Holographiemethode vor, die sich für Vollfeldabbildungen mit kurzen kohärenten Röntgenpulsen als vorteilhaft erweisen und neue Einsichten in die ultraschnelle Physik liefern könnte.<br>We have characterized the limitations of the most powerful and widely used 3D X-ray imaging approach, transmission X-ray microscopy with tomographic reconstruction. We show that 3D resolution in this approach is limited by the depth of field. To investigate alternatives, we perform simulations of a confocal transmission X-ray microscope and a FIB-SXM. We show that FIB-SXM is a very promising approach that could o er 3D isotropic resolution at 10 nm with dramatically improved signal to noise. We also introduce a new holography method that could prove bene cial for full eld imaging with short coherent X-ray pulses and yield new insights into ultrafast physics.

The fundamental theme my thesis explores is the relationship between genetic variation and phenotypic variation. It addresses three main questions. What is the genetic architecture of traits in the HS? How can sequence information help identifying the sequence variants and genes responsible for phenotypic variation? Are the genetic factors contributing to phenotypic variation in the rat homologous to those contributing to variation in the same phenotype in the mouse? To address these questions, I analysed data collected by the EURATRANS consortium on 1,407 Heterogeneous Stock (HS) rats descended from eight inbred strains through sixty generations of outbreeding. The HS rats were genotyped at 803,485 SNPs and 160 measures relevant to a number of models of disease (e.g. anxiety, type 2 diabetes, multiple sclerosis) were collected. The eight founders of the Stock were genotyped and sequenced. I identified loci in the genome that contribute to phenotypic variation (Quantitative Trait Loci, QTLs), and integrated sequence information with the mapping results to identify the genetic variants underlying the QTLs. I made some important observations about the nature of genetic architecture in rats, and how this compares to mice and humans. I also showed how sequence information can be used to improve mapping resolution, and in some cases to identify causal variants. However, I report an unexpected observation: at the majority of QTLs, the genetic effect cannot be accounted for by a single variant. This finding suggests that genetic variation cannot be reduced to sequence variation. This complexity will need to be taken into account by studies that aim at unravelling the genetic basis of complex traits.