177 research outputs found

    Non-target by-catch in the Maltese bluefin tuna (Thunnus thynnus) longline fishery (Central Mediterranean)

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    The Bluefin Tuna longline fishery is one of the most important pelagic fisheries in the Mediterranean but recently there has been increasing concern about the catches of non-target species. This study presents an assessment of the non-target by-catch from the Maltese Bluefin Tuna longline fleet and examines the effect of various environmental and spatiotemporal factors on non-target species catch rates. Field observations were made during 85 fishing days. In terms of number, Bluefin Tuna comprised a relatively small portion of the total catch while the Loggerhead Turtle (Caretta caretta) was the predominant by-catch species. Catch Per Unit Effort (CPUE) was calculated in terms of weight (kg/1000hooks/hr) and number (no/1000hooks/hr) for all the species caught. General Linear Mixed Models (GLMMs) were applied to examine the effect of environmental and spatiotemporal variables on non-target bycatch CPUE. The model for CPUE (number) was not found to be significant. Date, lunar cycle, species and longitude were found to be significantly correlated with CPUE (weight). The results of this study suggests the need for the continual implementation of mitigation measures to minimise the impacts of fishing activities on threatened non-target species in the Mediterranean.peer-reviewe

    Quantitative optical spectroscopy of 87^{87}Rb vapour in the Voigt geometry in DC magnetic fields up to 0.4T

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    We present a detailed spectroscopic investigation of a thermal ⁸⁷Rb atomic vapour in magnetic fields up to 0.4T in the Voigt geometry. We fit experimental spectra with our theoretical model ElecSus and find excellent quantitative agreement, with RMS errors of backsim0.3%. We extract the magnetic field strength and the angle between the polarisation of the light and the magnetic field from the atomic signal and find excellent agreement to within backsim1% with a commercial Hall probe. Finally, we present an investigation of the relative sensitivity of this technique to variations in the field strength and angle with a view to enabling atom-based high-field vector magnetometry

    Acute exercise facilitates brain function and cognition in children who need it most: An ERP study of individual differences in inhibitory control capacity

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    AbstractThe present study examined the effects of moderate-intensity aerobic exercise on aspects of cognitive control in two groups of children categorized by higher- and lower-task performance. Event-related brain potentials (ERPs) were collected in 40 preadolescent children during a modified flanker task following 20min of treadmill walking and seated rest on separate occasions. Participants were bifurcated into two groups based on task performance following the resting session. Findings revealed that following exercise, higher-performers maintained accuracy and exhibited no change in P3 amplitude compared to seated rest. Lower-performers demonstrated a differential effect, such that accuracy measures improved, and P3 amplitude increased following exercise. Lastly, both groups displayed smaller N2 amplitude and shorter P3 latency following exercise, suggesting an overall facilitation in response conflict and the speed of stimulus classification. The current findings replicate prior research reporting the beneficial influence of acute aerobic exercise on cognitive performance in children. However, children with lower inhibitory control capacity may benefit the most from single bouts of exercise. These data are among the first to demonstrate the differential effect of physical activity on individuals who vary in inhibitory control, and further support the role of aerobic exercise for brain health during development

    Round Robin Test of Residual Resistance Ratio of Nb3Sn Composite Superconductors

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    In this paper, a round robin test of residual resistance ratio (RRR) is performed for Nb3Sn composite superconductors prepared by an internal tin method by six institutes with the international standard test method described in IEC 61788-4. It was found that uncertainty mainly resulted from determination of the cryogenic resistance from the intersection of two straight lines drawn to fit the voltage versus temperature curve around the resistive transition. The measurement clarified that RRR can be measured with expanded uncertainty not larger than 5% with the coverage factor 2 by using this test method

    The sweet spot in sustainability: a framework for corporate assessment in sugar manufacturing

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    The assessment of corporate sustainability has become an increasingly important topic, both within academia and in industry. For manufacturing companies to conform to their commitments to sustainable development, a standard and reliable measurement framework is required. There is, however, a lack of sector-specific and empirical research in many areas, including the sugar industry. This paper presents an empirically developed framework for the assessment of corporate sustainability within the Thai sugar industry. Multiple case studies were conducted, and a survey using questionnaires was also employed to enhance the power of generalisation. The developed framework is an accurate and reliable measurement instrument of corporate sustainability, and guidelines to assess qualitative criteria are put forward. The proposed framework can be used for a company’s self-assessment and for guiding practitioners in performance improvement and policy decision-maki

    Remodelling of human atrial K+ currents but not ion channel expression by chronic β-blockade

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    Chronic β-adrenoceptor antagonist (β-blocker) treatment in patients is associated with a potentially anti-arrhythmic prolongation of the atrial action potential duration (APD), which may involve remodelling of repolarising K+ currents. The aim of this study was to investigate the effects of chronic β-blockade on transient outward, sustained and inward rectifier K+ currents (ITO, IKSUS and IK1) in human atrial myocytes and on the expression of underlying ion channel subunits. Ion currents were recorded from human right atrial isolated myocytes using the whole-cell-patch clamp technique. Tissue mRNA and protein levels were measured using real time RT-PCR and Western blotting. Chronic β-blockade was associated with a 41% reduction in ITO density: 9.3 ± 0.8 (30 myocytes, 15 patients) vs 15.7 ± 1.1 pA/pF (32, 14), p < 0.05; without affecting its voltage-, time- or rate dependence. IK1 was reduced by 34% at −120 mV (p < 0.05). Neither IKSUS, nor its increase by acute β-stimulation with isoprenaline, was affected by chronic β-blockade. Mathematical modelling suggested that the combination of ITO- and IK1-decrease could result in a 28% increase in APD90. Chronic β-blockade did not alter mRNA or protein expression of the ITO pore-forming subunit, Kv4.3, or mRNA expression of the accessory subunits KChIP2, KChAP, Kvβ1, Kvβ2 or frequenin. There was no reduction in mRNA expression of Kir2.1 or TWIK to account for the reduction in IK1. A reduction in atrial ITO and IK1 associated with chronic β-blocker treatment in patients may contribute to the associated action potential prolongation, and this cannot be explained by a reduction in expression of associated ion channel subunits

    A synopsis of the Ordovician System in its birthplace - Britain and Ireland

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    Rock successions in Britain and Ireland, and more especially those in North Wales, were instrumental in the founding and naming of the Ordovician System, and the Anglo-Welsh series established both initially and subsequently were used widely as a standard for Ordovician chronostratigraphy. Although now largely superseded in the global scheme of series and stages, they retain their local and regional importance. The Ordovician System in Britain and Ireland documents the history of a segment of the Earth's crust that incorporated opposing peri-Gondwanan and peri-Laurentian/Laurentian margins of the Iapetus Ocean during its closure, and is accordingly complex. The complexity arises from the volcanic and tectonic processes that accompanied oceanic closure coupled with the effects of eustatic sea-level changes, including the far-field effects of the Late Ordovician glaciation. For the past three decades, Ordovician successions in Britain and Ireland have been discussed in terms of terranes. Here we review Ordovician successions in each terrane, incorporating the results of recent research and correlating those successions via biostratigraphical schemes and radiometric dates to the global Ordovician series and stages
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