3,260 research outputs found

    Systematic-free inference of the cosmic matter density field from SDSS3-BOSS data

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    We perform an analysis of the three-dimensional cosmic matter density field traced by galaxies of the SDSS-III/BOSS galaxy sample. The systematic-free nature of this analysis is confirmed by two elements: the successful cross-correlation with the gravitational lensing observations derived from Planck 2018 data and the absence of bias at scales k103102hk \simeq 10^{-3}-10^{-2}h Mpc1^{-1} in the a posteriori power spectrum of recovered initial conditions. Our analysis builds upon our algorithm for Bayesian Origin Reconstruction from Galaxies (BORG) and uses a physical model of cosmic structure formation to infer physically meaningful cosmic structures and their corresponding dynamics from deep galaxy observations. Our approach accounts for redshift-space distortions and light-cone effects inherent to deep observations. We also apply detailed corrections to account for known and unknown foreground contaminations, selection effects and galaxy biases. We obtain maps of residual, so far unexplained, systematic effects in the spectroscopic data of SDSS-III/BOSS. Our results show that unbiased and physically plausible models of the cosmic large scale structure can be obtained from present and next-generation galaxy surveys

    Design of a low-noise aeroacoustic wind tunnel facility at Brunel University

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    This paper represents the design principle of a quiet, low turbulence and moderately high speed aeroacoustic wind tunnel which was recently commissioned at Brunel University. A new hemi-anechoic chamber was purposely built to facilitate aeroacoustic measurements. The wind tunnel can achieve a maximum speed of about 80 ms-1. The turbulence intensity of the free jet in the potential core is between 0.1–0.2%. The noise characteristic of the aeroacoustic wind tunnel was validated by three case studies. All of which can demonstrate a very low background noise produced by the bare jet in comparison to the noise radiated from the cylinder rod/flat plate/airfoil in the air stream.The constructions of the aeroacoustic wind tunnel and the hemi-anechoic chamber are financially supported by the School of Engineering and Design at Brunel University

    Moralka i metafizika

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    Varia mala hodiernum statum theologiae moralis premunt. Inter haec merito numeraturur nocua illa eiusdem a metaphysica separatio. Huic vulneri remedia afferenda sunt. Concretum ac mirabile exemplum habes in S. Thoma. Hic namque, quamvis philosophiam a theologia apprime distinguat, minime tamen separat. In SUMMA enim philosophicae speculationes cum theologicis notionibus amice iunguntur. Bonitas entis fit bonitas moralis in ipsa actione bona seu virtuosa. Theologia moralis sine notione metaphysica boni solido fundamento caret. Ita, nefas est distinguere moralem praeceptorum et moralem consiliorum, cum ad perfectionem tendere commune omnium officium existat. Bonum convertitur cum perfecto, et perfecto est quaedam entis expansio, plenitudo. Doctrina de imperfectionibus huic conceptui non satisfacit. Obligationi derogare est defectus, peccatum. Ex radicatione boni in ente idea boni realis et obiectivi sponte exurgit. Moralis obiectiva est regula humanorum actuum, nec moralis subiectiva (moralis responsabilitatis, meriti) aliud officium habet nisi tendere ad hoc ut moralis obiectiva in praxim deducatur

    Isolation, identification and characterisation of ballan wrasse Labrus bergylta plasma pigment

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    This work was supported by co-funding from Innovate U.K. (formerly Technology Strategy Board), Marine Harvest Scotland and Scottish Seafarms Ltd (project ref: 81199) as well as the University of Stirling, Impact studentship funding scheme. Mass spectrometry analysis was performed by the BSRC Mass Spectrometry Facility, University of St Andrews.This study confirmed that observations of blue-green colouration in plasma fractions of the ballan wrasse Labrus bergylta were caused by the linear tetra-pyrrole biliverdin and that the molecule was of the physiologically relevant IXα isomer. Accumulation appears driven by chromogenic association with an unknown protein moiety which precludes enzymatic reduction and would suggest active management. It was demonstrated that the pigment did not fluctuate relative to ontogeny, or indeed binary gender in the species of interest, but mobilisation and depletion in the subset of individuals undergoing sex change at the time of study supports a potential association with gender inversion processes. It is of note that although biliverdin does have some effect on external colouration, the evidence is indicative that crypsis is a supplementary function thus other factors must be considered.PostprintPeer reviewe

    Application of passive-acoustic telemetry to explore the behaviour of ballan wrasse (Labrus bergylta) and lumpfish (Cyclopterus lumpus) in commercial Scottish salmon sea-pens

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    A passive-acoustic telemetry system was used for the first time for the fine-scale, three-dimensional tracking of individual cleaner fish in commercial Scottish salmon sea-pens in full commercial operation. The aim was to test the system performance and provide baseline data on the comparative distribution and swimming activity of individual ballan wrasse and lumpfish under standard farm practices with the long-term aim of informing stocking and husbandry strategies. In March 2015, wild ballan wrasse (Labrus bergylta) (115 ± 20 g; n = 13) and farmed lumpfish (Cyclopterus lumpus) (281 ± 42 g; n = 13) previously deployed in June–October 2014 were recaptured, implanted with acoustic tags pinging every 6–12 s and released into their original sea cage holding Atlantic salmon (Q2 2014; 2059 ± 35 g mean-weight). Control tags were deployed in cleaner fish hides to validate the system performance. Positional data from nine specimens per species were analysed from March 24th to June 1st 2015, during which time water temperature rose from 7.2 to 9.1 °C and water salinity averaged 26.8 ± 1.5 ppt at 4 m depth. The accuracy of the acoustic positions averaged 0.6 m across the three dimensions of all control tags and was < 1 m in 93% of all cases. Significant differences in the distribution and activity of ballan wrasse and lumpfish were observed. Ballan wrasses spent 60 ± 2% of the day-time at or below 15 m, were positioned at significantly shallower depths at night and seldom used the hides provided despite an apparent resting behaviour at the pen bottom and corners. In comparison, lumpfish spent over 80% of the time above 10 m, used hides extensively and preferentially at night (50.1 ± 2.1% at night), but to a lesser extent when the water temperature increased. The acoustic tracking system proved to be an effective tool for visualising cleaner fish behaviour under challenging farm conditions, and the study highlights the critical role of hides in cleaner fish husbandry. Overall, the study quantified species-specific cleaner fish distribution in salmon net-pens supporting distinct interactions with the salmon stock and seasonal behaviour profiles. The results support the current commercial strategy of using two cleaner fish species against sea lice and the need for species-specific management strategies to optimise delousing activity
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