786 research outputs found
The precision of international market sampling for North Sea herring and its influence on assessment
Market sampling is a key source of data for catch-at-age-based assessment. Little has been documented about the influence of potential error in these data on the precision of assessments and the management information they produce. This paper presents the results of a study of the precision of North Sea herring fish market sampling carried out by the UK, Denmark and the Netherlands. Data from eight years of market sampling were analysed to obtain the precision of estimated numbers-at-age in the catch. The market sample data was then used to estimate 1000 realisations of the international catch-at-age and mean weightsat- age in the catch. Three methods of estimating the variability of missing catch data were used and three options for the catch-at-age matrices were computed. These base datasets were utilised to obtain 1000 assessments conditional on the ICA (Integrated Catch-at-age Analysis) model. From the outcome of these assessments the influence of the market sampling programmes on the management of the stock are presented as 95âonfidence intervals on the main management parameters (recruitment, SSB, F0-1 and F2-6). In addition, the influence of missing data is estimated. The implications of our conclusions on the requirements from a market sampling programme are discusse
AffecTech- an affect-aware interactive AV Artwork
New developments in real-time computing and body-worn sensor technology allow us to explore not just visible gestures using inertial sensors, but also invisible changes in an individualâs physiological state using bio-sensors (Kim & AndrĂ© 2008). This creates an opportunity for a more intimate interaction between the observer and technology-based art (Gonsalves 2008). We present a technical overview of the AffecTech system; a bio-signal based interactive audio-
visual installation commissioned as part of the pre-ISEA symposium in November 2008. Observers were invited to sit on one of 2 sensor-enhanced chairs (Coghlan & Knapp 2008), which transmitted physiological data about the occupant to a central control system. This data was used to control and modulate interactive visuals, live video feeds and a surround sound score, with events and interactions dependent on the observersâ affective/emotional state and the disparity or similarity between the bio-signals of the chairs occupants. This technical
overview is followed by an examination of the outcomes of the project, from both the artistic and technical viewpoints, with recommendations for modification in future implementations
Characteristics of relativistic microburst intensity from SAMPEX observations
Relativistic electron microbursts are an important electron loss process from the radiation belts into the atmosphere. These precipitation events have been shown to significantly impact the radiation belt fluxes and atmospheric chemistry. In this study we address a lack of knowledge about the relativistic microburst intensity using measurements of 21,746 microbursts from the Solar Anomalous Magnetospheric Particle Explorer (SAMPEX). We find that the relativistic microburst intensity increases as we move inward in L, with a higher proportion of lowâintensity microbursts (2,250â[MeVâcm2âsrâs]â1) in the 03â11 magnetic local time region increases as geomagnetic activity increases, consistent with changes in the whistler mode chorus wave activity. Comparisons between relativistic microburst properties and trapped fluxes suggest that the microburst intensities are not limited by the trapped flux present alongside the scattering processes. However, microburst activity appears to correspond to the changing trapped flux; more microbursts occur when the trapped fluxes are enhancing, suggesting that microbursts are linked to processes causing the increased trapped fluxes. Finally, modeling of the impact of a published microburst spectra on a flux tube shows that microbursts are capable of depleting <500âkeV electrons within 1 hr and depleting higherâenergy electrons in 1â23 hr
Open String Thermodynamics and D-Branes
We study the thermodynamics of open superstrings in the presence of
-dimensional D-branes. We get some finite temperature dualities relating the
one-loop canonical free energy of open strings to the self-energy of D-branes
at dual temperature. For the open bosonic string the inverse dual temperature
is, as expected, the dual length under T-duality, .
On the contrary, for the , type-I superstring the dual temperature is
given by -duality, . We also study the
emergence of the Hagedorn singularity in the dual description as triggered by
the coupling of the D-brane to unphysical tachyons as well as the high
temperature limit.Comment: 16 pages, harvmac (b), epsf, 2 figures included. Minor changes;
discussion in section 4 has been expanded and two footnotes and a reference
adde
Chromosome painting among Proboscidea, Hyracoidea and Sirenia: support for Paenungulata (Afrotheria, Mammalia) but not Tethytheria
Despite marked improvements in the interpretation of systematic relationships within Eutheria, particular nodes, including Paenungulata (Hyracoidea, Sirenia and Proboscidea), remain ambiguous. The combination of a rapid radiation, a deep divergence and an extensive morphological diversification has resulted in a limited phylogenetic signal confounding resolution within this clade both at the morphological and nucleotide levels. Cross-species chromosome painting was used to delineate regions of homology between Loxodonta africana (2n=56), Procavia capensis (2n=54), Trichechus manatus latirostris (2n=48) and an outgroup taxon, the aardvark (Orycteropus afer, 2n=20). Changes specific to each lineage were identified and although the presence of a minimum of 11 synapomorphies confirmed the monophyly of Paenungulata, no change characterizing intrapaenungulate relationships was evident. The reconstruction of an ancestral paenungulate karyotype and the estimation of rates of chromosomal evolution indicate a reduced rate of genomic repatterning following the paenungulate radiation. In comparison to data available for other mammalian taxa, the paenungulate rate of chromosomal evolution is slow to moderate. As a consequence, the absence of a chromosomal character uniting two paenungulates (at the level of resolution characterized in this study) may be due to a reduced rate of chromosomal change relative to the length of time separating successive divergence events
Transposable temperate phages promote the evolution of divergent social strategies in Pseudomonas aeruginosa populations
Transposable temperate phages randomly insert into bacterial genomes, providing increased supply and altered spectra of mutations available to selection, thus opening alternative evolutionary trajectories. Transposable phages accelerate bacterial adaptation to new environments, but their effect on adaptation to the social environment is unclear. Using experimental evolution of Pseudomonas aeruginosa in iron-limited and iron-rich environments, where the cost of producing cooperative iron-chelating siderophores is high and low, respectively, we show that transposable phages promote divergence into extreme siderophore production phenotypes. Iron-limited populations with transposable phages evolved siderophore overproducing clones alongside siderophore non-producing cheats. Low siderophore production was associated with parallel mutations in pvd genes, encoding pyoverdine biosynthesis, and pqs genes, encoding quinolone signalling, while high siderophore production was associated with parallel mutations in phenazine-associated gene clusters. Notably, some of these parallel mutations were caused by phage insertional inactivation. These data suggest that transposable phages, which are widespread in microbial communities, can mediate the evolutionary divergence of social strategies
Cow welfare in grass based milk production systems
End of project reportUnder this project, aspects of pasture based milk production systems, namely different milking frequency and feeding strategies as well as genetic selection for improved fitness using the Irish Economic Breeding Index (EBI) were evaluated in terms of dairy cow behaviour, health, immune function and reproductive performance. Additionally, a typical Irish pasture based system was compared to one in which cows were kept indoors in cubicles and fed a total mixed ration for the duration of lactation in order to elucidate the perceived benefits of pasture based systems for dairy cow welfare
Functional and genetic analysis of regulatory regions of coliphage H-19B: location of shiga-like toxin and lysis genes suggest a role for phage functions in toxin release
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74784/1/j.1365-2958.1998.00890.x.pd
- âŠ