707 research outputs found

    A qualitative analysis of the interfaces between urban underground metro infrastructure and its environment in London

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    As urban environments densify and cities across the world employ urban underground metros for the effective rapid movement of millions of people a day, there is an essential need to ensure the safe continued presence and operation of those metros. To achieve this, the authors argue there is a need for a more detailed qualitative analysis of how urban underground metro infrastructure and its environment interface. Failure to do so could potentially lead to the development of inaccurate asset management data. This would subsequently lead to the implementation of flawed Building Information Modelling processes for 2, 3, and 4D modelling and mapping, of existing and proposed infrastructure. Following a review of existing asset management approaches which confirms the need for qualitative approaches to the analyses of the interfaces, this paper presents findings from a detailed case study, in the Bayswater area of the City of Westminster in West London, UK.The processes employed for the detailed case study form part of proposed (ultimately) standardised approaches to the gathering, analysis, and sharing, of multi-disciplinary evidence-based data, developed by the authors. Such data is essential to enable effective asset and urban management processes, now and for the future

    Commercial golf glove effects on golf performance and forearm muscle activity

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    The study aimed to determine whether or not commercial golf gloves influence performance variables and forearm muscle activity during golf play. Fifteen golfers participated in the laboratory based study, each performing 8 golf swings with a Driver and 7-iron whilst wearing a glove and 8 without wearing the glove. Club head speed, ball speed and absolute carry distance performance variables were calculated. Surface electromyography was recorded from the flexor digitorum superficialis and extensor carpi radialis brevis on both forearm muscles. Club head speed, ball speed and absolute carry distance was significantly higher when using the Driver with the glove in comparison to the Driver without the glove (p < 0.05). No significant differences were evident when using the 7-iron and no significant differences were displayed in muscle activity in either of the conditions. Findings from this study suggest that driving performance is improved when wearing a glove

    DETERMINANTS OF THE MAIZE BOARD-MILLER MARKETING MARGIN IN SOUTH AFRICA : 1977-1993

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    Determinants of the Maize Board - Miller (MBM) marketing margin for the period 1977-1993 (period defined by data limitations) are identified for a mark-up model using Three-Stage Least Squares Regression (3SLS) and Principal Component Analysis. The MBM margin was positively related to the real miller white maize meal selling price, real variable processing costs, and a change in Maize Board pricing policy after 1987

    The heterogeneous soil environment:are there preferential pathways for fungal spread?

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    Most studies with soil-borne pathogenic fungi have been done with little explicit characterisation of soil structure within which fungi spread and biotic interactions occur. Soil, however, constitutes a framework of surfaces formed by old root channels, cracks or biopores in combination with aggregates. Using epidemiological and soil biological techniques in controlled environments we investigated the effect of soil heterogeneity on fungal growth dynamics. We show that cracks and larger pores can act either as preferential pathways or barriers for the spread of fungal plant pathogens through soil. Understanding the effect of soil structure on pathogen and antagonist dynamics is therefore critical for our understanding of epidemics and the development of control strategies in a heterogeneous environment

    Localised necrosis of scrotum (Fournier's gangrene) in a spinal cord injury patient – a case report

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    BACKGROUND: Men with spinal cord injury (SCI) appear to have a greater incidence of bacterial colonisation of genital skin as compared to neurologically normal controls. We report a male patient with paraplegia who developed rapidly progressive infection of scrotal skin, which resulted in localised necrosis of scrotum (Fournier's gangrene). CASE PRESENTATION: This male patient developed paraplegia at T-8 level 21 years ago at the age of fifteen years. He has been managing his bladder by wearing a penile sheath. He noticed redness and swelling on the right side of the scrotum, which rapidly progressed to become a black patch. A wound swab yielded growth of methicillin-resistant Staphylococcus aureus (MRSA). Necrotic tissue was excised. Culture of excised tissue grew MRSA. A follow-up wound swab yielded growth of MRSA and mixed anaerobes. The wound was treated with regular application of povidone-iodine spray. He made good progress, with the wound healing gradually. CONCLUSION: It is likely that the presence of a condom catheter, increased skin moisture in the scrotum due to urine leakage, compromised personal hygiene, a neurogenic bowel and subtle dysfunction of the immune system contributed to colonisation, and then rapidly progressive infection in this patient. We believe that spinal cord injury patients and their carers should be made aware of possible increased susceptibility of SCI patients to opportunistic infections of the skin. Increased awareness will facilitate prompt recourse to medical advice, when early signs of infection are present

    A Kriging procedure for processes indexed by graphs

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    International audienceWe provide a new kriging procedure of processes on graphs. Based on the construction of Gaussian random processes indexed by graphs, we extend to this framework the usual linear prediction method for spatial random fields, known as kriging. We provide the expression of the estimator of such a random field at unobserved locations as well as a control for the prediction error

    A set of inequalities in factor analysis

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    Inequalities relating the communalities to the multiple-correlation coefficients are derived. They are stronger than the well-known inequalities which have played an important role in factor analysis for the past thirty years. Necessary and sufficient conditions for equality are obtained.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45719/1/11336_2005_Article_BF02289534.pd

    Initial cyclostratigraphy of the middle Nama Group (Schwarzrand Subgroup) in southern Namibia

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    The Ediacaran Period includes critical evolutionary trends of early complex life as well as climatic variations associated with ocean oxygenation, glaciations, and carbon cycling, which are still poorly understood in terms of astronomical climate forcing. The middle Nama Group in southern Namibia was deposited during the late Ediacaran in mainly shallow marine environments within a foreland basin and consists of hierarchically arranged depositional sequences. Here, we test a possible astronomical origin of these sedimentary variations by developing an initial cyclostratigraphic framework based on satellite images integrated with recently published high-precision U-Pb zircon ages. Regular sedimentary alternations occur dominantly on scales of several tens of meters, accompanied by smaller- and larger-scale variations, and are correlatable over distances of ∼50 km. Throughout the studied succession, 35 to 39 alternations are recognized on this dominant scale, which have an average duration of ∼120–180 k.y. This duration corresponds well with the period of short eccentricity (∼100 k.y.), given the likely presence of hiatuses, or alternatively, the period of obliquity amplitude modulation (∼173 k.y.), which would imply no time is missing on this scale. The dominant alternations are consistent with previously identified medium-scale sequences in this succession, which have been interpreted to record fluctuations in relative or eustatic sea level. We hypothesize that astronomically-forced fluctuations in eustatic sea level modulated deposition of the middle Nama Group. Geochemical studies suggested a relation between fossil distribution, redox variability and sea level, implying that astronomical forcing may have played a role in the distribution of early complex life

    Weak pairwise correlations imply strongly correlated network states in a neural population

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    Biological networks have so many possible states that exhaustive sampling is impossible. Successful analysis thus depends on simplifying hypotheses, but experiments on many systems hint that complicated, higher order interactions among large groups of elements play an important role. In the vertebrate retina, we show that weak correlations between pairs of neurons coexist with strongly collective behavior in the responses of ten or more neurons. Surprisingly, we find that this collective behavior is described quantitatively by models that capture the observed pairwise correlations but assume no higher order interactions. These maximum entropy models are equivalent to Ising models, and predict that larger networks are completely dominated by correlation effects. This suggests that the neural code has associative or error-correcting properties, and we provide preliminary evidence for such behavior. As a first test for the generality of these ideas, we show that similar results are obtained from networks of cultured cortical neurons.Comment: Full account of work presented at the conference on Computational and Systems Neuroscience (COSYNE), 17-20 March 2005, in Salt Lake City, Utah (http://cosyne.org
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