1,476 research outputs found

    Modelling the Gross Cost of Transporting Pig Slurry to Tillage Spread Lands in a Post Transition Arrangement within the Nitrates Directive.

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    working paperThe context of this paper is in the phasing out of the transitional arrangement under the Nitrates Directive. As there is relatively little grassland capable of taking significant amounts of pig slurry available in the vicinity of the main pig production areas, in this paper we attempt to quantify the cost of transporting this slurry to the nearest available tillage land. The approach taken was to examine the geographic structure underlying the pig sector in Ireland using Geographic Information Systems (GIS) technology. The study highlighted the differential cost with, amounting to 10% of gross margin on average and as high in major pig producing areas as 21.5% in Longford and 16.6% in Cavan, while lower at 7-9% in South Tipperary and Cork. Thus while the problem is significant, the impact is not constant across the country, highlighting the value of a spatial analytical approach. Future work should assess the existing cost of spreading manure in order to be able to ascertain the net cost of spreading on tillage lands. The robustness of the results also need to be tested to assess the implications of changes in the prices of fossil fuels and fertilisers, both in terms of the cost function and in terms of the cost of substitutable mineral fertilise

    Analysis of repeated high-intensity running performance in professional soccer

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    The aims of this study conducted in a professional soccer team were two-fold: to characterise repeated high-intensity movement activity profiles in official match-play; b) to inform and verify the construct validity of tests commonly used to determine repeated-sprint ability in soccer by investigating the relationship between the results from a test of repeated-sprint ability and repeated high-intensity performance in competition. High-intensity running performance (movement at velocities >19.8 km/h for a minimum of 1-s duration) in 20 players was measured using computerised time motion analysis. Performance in 80 French League 1 matches was analysed. In addition, 12 out of the 20 players performed a repeated-sprint test on a non-motorized treadmill consisting of 6 consecutive 6s sprints separated by 20s passive recovery intervals. In all players, the majority of consecutive high-intensity actions in competition were performed after recovery durations ≥61s, recovery activity separating these efforts was generally active in nature with the major part of this spent walking, and players performed 1.1±1.1 repeated high-intensity bouts (a minimum of 3 consecutive high-intensity with a mean recovery time ≤20s separating efforts) per game. Players reporting lowest performance decrements in the repeated-sprint ability test performed more high-intensity actions interspersed by short recovery times (≤20s, p<0.01 and ≤30s, p<0.05) compared to those with higher decrements. Across positional roles, central-midfielders performed a greater number of high-intensity actions separated by short recovery times (≤20s) and spent a larger proportion of time running at higher intensities during recovery periods while fullbacks performed the most repeated high-intensity bouts (statistical differences across positional roles from p<0.05 to p<0.001). These findings have implications for repeated high-intensity testing and physical conditioning regimens

    Searching for Serendipitous Analogies

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    Analogical reasoning is an acknowledged process behind many episodes of creativity. Typically, the creator chances upon information unrelated to the given problem – and solves the problem by analogy with this accidental source of inspiration. Current models of analogical retrieval do not explain how semantically unrelated source domains are retrieved. We present the RADAR algorithm that maps domains into a separate structure space, where domains with similar topological attributes are colocated. Each axis in structure space records the occurrence frequency of that feature in each domain. Nearest neighbour retrieval in structure space identifies structurally similar domains - from a diversity of semantic backgrounds. Structure based retrieval opens the possibility for creating an analogy model with far greater creativity potential than human reasoning

    Features of Structure for Anaology Retrieval

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    Spontaneously retrieving analogies from presented problem data is an important phase of analogical reasoning, influencing many related cognitive processes. Existing models have focused on semantic similarity, but structural similarity is also a necessary requirement of any analogical comparison. We present a new technique for performing structure based analogy retrieval. This is founded upon derived attributes that explicitly encode elementary structural qualities of a domains representation. Crucially, these attributes are unrelated to the semantic content of the domain information, and encode only its structural qualities. We describe a number of derived attributes and detail the computation of the corresponding attribute values. We examine our models operation, detailing how it retrieves both semantically related and unrelated domains. We also present a comparison of our algorithms performance with existing models, using a structure rich but semantically impoverished domai

    Simultaneous X-ray/optical observations of GX 9+9 (4U 1728-16)

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    We report on the results of the first simultaneous X-ray (RXTE) and optical (SAAO) observations of the luminous low mass X-ray binary (LMXB) GX 9+9 in 1999 August. The high-speed optical photometry revealed an orbital period of 4.1958 hr and confirmed previous observations, but with greater precision. No X-ray modulation was found at the orbital period. On shorter timescales, a possible 1.4-hr variability was found in the optical light curves which might be related to the mHz quasi-periodic oscillations seen in other LMXBs. We do not find any significant X-ray/optical correlation in the light curves. In X-rays, the colour-colour diagram and hardness-intensity diagram indicate that the source shows characteristics of an atoll source in the upper banana state, with a correlation between intensity and spectral hardness. Time-resolved X-ray spectroscopy suggests that two-component spectral models give a reasonable fit to the X-ray emission. Such models consist of a blackbody component which can be interpreted as the emission from an optically thick accretion disc or an optically thick boundary layer, and a hard Comptonized component for an extended corona.Comment: 19 pages, 13 figures; accepted for publication in MNRA
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