580 research outputs found

    A haplotype-resolved draft genome of the European sardine (Sardina pilchardus)

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    The European sardine (Sardina pilchardus Walbaum, 1792) is culturally and economically important throughout its distribution. Monitoring studies of sardine populations report an alarming decrease in stocks due to overfishing and environmental change, which has resulted in historically low captures along the Iberian Atlantic coast. Important biological and ecological features such as population diversity, structure, and migratory patterns can be addressed with the development and use of genomics resources.Agência financiadora Portuguese national funds from FCT-Foundation for Science and Technology: UID/Multi/04326/2016; European Regional Development Fund (FEDER): 22153-01/SAICT/2016; ALG-01-0145-FEDER-022121; ALG-01-0145-FEDER-022231; MAR2020 operational programme of the European Maritime and Fisheries Fund (project SARDI-NOMICS): MAR-01.04.02-FEAMP-0024; European Union's Horizon 2020 research and innovation programme: 654008info:eu-repo/semantics/publishedVersio

    Simulative Determination of Effective Mechanical Properties for Digitally Generated Foam Geometries

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    Metal foams constitute a promising and emerging material class in the context of lightweight construction. There exists a variety of different foam topologies, on which resulting mechanical properties depend. To maximize the potential of foams in material use under mechanical load, the present work addresses the question how different geometrical parameters influence the material behaviour. Therefore, an algorithm for digital generation and design of open pore foam structures is presented, that allows to regulate the geometry precisely. A method for retrieving effective mechanical properties from numerical simulations of compression tests in the elastic regime is introduced. Additionally, the representativeness of foam volumes considered for simulations is investigated. This yields a fully digital workflow, which enables the investigation of geometry influence on mechanical properties. This approach is used to conduct simulation studies on generated foam structures with a systematic variation of geometrical parameters. Herein, a range of effective Young\u27s moduli varying by up to a factor of 1.3 for different foam structures at the same porosity is found. This shows a significant impact of the foam geometry on the elastic properties of metal foams. The presented methodology yields insights, which can guide design and optimization of materials for specific applications

    Yolk vitamin E positively affects prenatal growth but not oxidative status in yellow-legged gull embryos

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    Parental effects occur whenever the phenotype of parents or the environment that they experience influences the phenotype and fitness of their offspring. In birds, parental effects are often mediated by the size and biochemical quality of the eggs in terms of maternally transferred components. Exogenous antioxidants are key egg components that accomplish crucial physiological functions during early life. Among these, vitamin E plays a vital role during prenatal development when the intense metabolism accompanying rapid embryo growth results in overproduction of pro-oxidant molecules. Studies of captive birds have demonstrated the positive effect of vitamin E supplementation on diverse phenotypic traits of hatchling and adult individuals, but its effects on embryo phenotype has never been investigated neither in captivity nor under a natural selection regime. In the present study, we experimentally tested the effect of the in ovo supplementation of vitamin E on morphological traits and oxidative status of yellow-legged gull (Larus michahellis) embryos. The supplementation of vitamin E promoted somatic growth in embryos soon before hatching, but did not affect their oxidative status. Our results suggest that maternally transferred vitamin E concentrations are optimized to prevent imbalances of oxidative status and the consequent raise of oxidative damage in yellow-legged gull embryos during prenatal development

    Morphological Disambiguation from Stemming Data

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    Morphological analysis and disambiguation is an important task and a crucial preprocessing step in natural language processing of morphologically rich languages. Kinyarwanda, a morphologically rich language, currently lacks tools for automated morphological analysis. While linguistically curated finite state tools can be easily developed for morphological analysis, the morphological richness of the language allows many ambiguous analyses to be produced, requiring effective disambiguation. In this paper, we propose learning to morphologically disambiguate Kinyarwanda verbal forms from a new stemming dataset collected through crowd-sourcing. Using feature engineering and a feed-forward neural network based classifier, we achieve about 89% non-contextualized disambiguation accuracy. Our experiments reveal that inflectional properties of stems and morpheme association rules are the most discriminative features for disambiguation

    A review of new TDR applications for measuring non-aqueous phase liquids (NAPLs) in soils

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    The time domain reflectometry (TDR) technique is a geophysical method that allows, in a time-varying electric field, the determination of dielectric permittivity and electrical conductivity of a wide class of porous materials. Measurements of the volumetric water content (θw) in soils is the most frequent application of TDR in Soil Science and Soil Hydrology. In last four decades several studies have sought to explore potential applications of TDR. Such studies (except those conducted on θw estimation) mainly focused on monitoring soil solute transport. In more recent times, innovative TDR approaches have also been implemented to extend current TDR fields of application to the problem of monitoring non-aqueous phase liquids (NAPLs) in variable saturated soils. NAPLs are organic compounds with low solubility in water and are characterised by a high mobility in the vadose zone. Due to their high toxicity, NAPLs constitute a severe geo-environmental problem, thus making detection and observation of such substances in soils an increasingly important issue. The present paper deals with these studies and aims to provide an up-to-date review of the main NAPL-TDR studies. To date, the literature has focused on TDR applications in three main fields: (i) NAPL monitoring in homogeneous, variable saturated soils, (ii) NAPL monitoring in layered variable saturated soils, and (iii) NAPL monitoring during soil decontamination processes. For an exhaustive and complete overview of TDR research in this field, we also recall the basic principles of TDR signal propagation, the functioning of a typical TDR device, and the dielectric mixing models that are widely used to interpret the dielectric response of NAPL-contaminated soils

    A method to improve size estimates of walleye pollock (Theragra chalcogramma) Atka mackerel (Pleurogrammus monopterygius) consumed by pinnipeds: digestion correction factors applied to bones and otoliths recovered in scats

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    The lengths of otoliths and other skeletal structures recovered from the scats of pinnipeds, such as Steller sea lions (Eumetopias jubatus), correlate with body size and can be used to estimate the length of prey consumed. Unfortunately, otoliths are often found in too few scats or are too digested to usefully estimate prey size. Alternative diagnostic bones are frequently recovered, but few bone-size to prey-size correlations exist and bones are also reduced in size by various degrees owing to digestion. To prevent underestimates in prey sizes consumed techniques are required to account for the degree of digestion of alternative bones prior to estimating prey size. We developed a method (using defined criteria and photo-reference material) to assign the degree of digestion for key cranial structures of two prey species: walleye pollock (Theragra chalcogramma) and Atka mackerel (Pleurogrammus monopterygius). The method grades each structure into one of three condition categories; good, fair or poor. We also conducted feeding trials with captive Steller sea lions, feeding both fish species to determine the extent of erosion of each structure and to derive condition-specific digestion correction factors to reconstruct the original sizes of the structures consumed. In general, larger structures were relatively more digested than smaller ones. Mean size reduction varied between different types of structures (3.3−26.3%), but was not influenced by the size of the prey consumed. Results from the observations and experiments were combined to be able to reconstruct the size of prey consumed by sea lions and other pinnipeds. The proposed method has four steps: 1) measure the recovered structures and grade the extent of digestion by using defined criteria and photo-reference collection; 2) exclude structures graded in poor condition; 3) multiply measurements of structures in good and fair condition by their appropriate digestion correction factors to derive their original size; and 4) calculate the size of prey from allometric regressions relating corrected structure measurements to body lengths. This technique can be readily applied to piscivore dietary studies that use hard remains of fish
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