708 research outputs found

    Asset management and governance: an analysis of fleet management process issues in an asset-intensive organization

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    Efficient asset management is a key performance driver for asset-intensive organizations. Achieving high utilization and return on investment on physical assets are central corporate objectives for public and private organisations alike. Current approaches on asset management include the engineering and governance perspectives. Both perspectives offer valuable but incomplete insights on the management of asset performance: experience demonstrates that an exclusive focus on one or the other may lead to sub-optimal asset and organizational performance. In this paper, we investigate how an integrated approach to asset management can be constructed in the context of vehicle fleets. Beginning with an analysis of how the asset management process is operated through the asset lifecycle, we identify key engineering and organizational factors influencing asset performance. The relationships between factors are analyzed to provide an integrated fleet asset management approach

    Stemless ball valve

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    A stemless ball valve comprising two flanges and a ball with a channel, two axis pins and two travel pins. One end of each axis and travel pin is fixedly attached to the ball, and the other end of each axis pin is lodged into a notch in the first or second flange such that the axis pin is allowed to rotate in the notch. The guide sleeve comprises two channels, and one end of each travel pin is situated within one of the two channels in the guide sleeve. An outer magnetic cartridge causes the inner magnetic cartridge and guide sleeve to rotate, and when the guide sleeve rotates, the travel pins move up and down within the channels in the guide sleeve. The movement of the travel pins within the channels in the guide sleeve causes the ball to rotate, thereby opening and closing the ball valve

    SAP - is it systematic research bias, which is to blame for such post implementation disappointment?

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    SAP is a major ERP Package that requires no introduction and research into the area is widespread and well reported. However, more and more reports are emerging of the failure of SAP as a package to meet the needs of business. This paper looks at the research of SAP for evidences of systematic research biases to see if that is the cause for such implementation failure being missed. A comprehensive literature search on SAP papers was undertaken with some alarming results showing a disturbing uncritical and possibly biased perspective from SAP Research literature

    Use of Water Quality Measurements to Detect Potential Septic System Input at Grand Lake, Oklahoma

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    The Pensacola Hydroelectric Project impounds the Neosho, Elk, and Spring Rivers in northeastern Oklahoma to form Grand Lake O' the Cherokees (Grand Lake). Grand Lake has extensive near-shore development with the majority of homes using septic systems to treat household wastewater. The soils that surround much of the lake are only marginally adequate to retain/treat septic leachate, so it is possible that effluent from some septic systems could reach the surface water of Grand Lake. This study investigated the relationship between factors that could increase the potential for septic system failure (housing density and age) and common water quality parameters that could indicate the presence of septic effluent in surface waters. A geographic information system (GIS) database was used categorize selected sites along the Grand Lake shoreline based on housing density and age. Water samples were taken at these sites through late spring, summer and early fall of 2006 and early spring, summer, and early fall of 2007, and a suite of water physical, chemical and bacterial parameters were measured. Flow regimes between the two field seasons were significantly different, with 2006 having low flow conditions and 2007 with record-breaking precipitation and flooding. Findings and Conclusions: No clear relationship was observed between water quality and the categories used to differentiate housing age and density, although site comparisons indicated a decreasing longitudinal gradient towards the dam for parameters such as total phosphorous, orthophosphate, nitrate, nitrite and ammonium. High variability was also observed for some water quality parameters within sample coves. Sampling with Polar Organic Chemical Samplers (POCIS) indicated organic wastewater compounds at most sites sampled with the most detected at the outfall of a wastewater treatment facility. Stable isotope (?N-15) indicates some potential nitrogen enrichment of some sites, but a more definitive investigation with increased replication is needed to better evaluate this relationship. Overall, no clear links between risk factors for septic system failure and water quality indicators of this failure were indicated in this study. Methods such as microbial source tracking and groundwater investigation may be necessary to characterize the relationship of septic systems and water quality.Environmental Sciences Progra

    Quadratic Speedups in Parallel Sampling from Determinantal Distributions

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    We study the problem of parallelizing sampling from distributions related to determinants: symmetric, nonsymmetric, and partition-constrained determinantal point processes, as well as planar perfect matchings. For these distributions, the partition function, a.k.a. the count, can be obtained via matrix determinants, a highly parallelizable computation; Csanky proved it is in NC. However, parallel counting does not automatically translate to parallel sampling, as classic reductions between the two are inherently sequential. We show that a nearly quadratic parallel speedup over sequential sampling can be achieved for all the aforementioned distributions. If the distribution is supported on subsets of size kk of a ground set, we show how to approximately produce a sample in O~(k12+c)\widetilde{O}(k^{\frac{1}{2} + c}) time with polynomially many processors for any constant c>0c>0. In the two special cases of symmetric determinantal point processes and planar perfect matchings, our bound improves to O~(k)\widetilde{O}(\sqrt k) and we show how to sample exactly in these cases. As our main technical contribution, we fully characterize the limits of batching for the steps of sampling-to-counting reductions. We observe that only O(1)O(1) steps can be batched together if we strive for exact sampling, even in the case of nonsymmetric determinantal point processes. However, we show that for approximate sampling, Ω~(k12−c)\widetilde{\Omega}(k^{\frac{1}{2}-c}) steps can be batched together, for any entropically independent distribution, which includes all mentioned classes of determinantal point processes. Entropic independence and related notions have been the source of breakthroughs in Markov chain analysis in recent years, so we expect our framework to prove useful for distributions beyond those studied in this work.Comment: 33 pages, SPAA 202

    A nexus perspective on competing land demands: Wider lessons from a UK policy case study

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    As nations develop policies for low-carbon transitions, conflicts with existing policies and planning tools are leading to competing demands for land and other resources. This raises fundamental questions over how multiple demands can best be managed. Taking the UK as an empirical example, this paper critiques current policies and practices to explore the interdependencies at the water-energy-food nexus. It considers how current land uses and related policies affect the UK’s resilience to climate change, setting out an agenda for research and practice relevant to stakeholders in land-use management, policy and modelling. Despite recent progress in recognising such nexus challenges, most UK land-related policies and associated science continue to be compartmentalised by both scale and sector and seldom acknowledge nexus interconnections. On a temporal level, the absence of an over-arching strategy leaves inter-generational trade-offs poorly considered. Given the system lock-in and the lengthy policy-making process, it is essential to develop alternative ways of providing dynamic, flexible, practical and scientifically robust decision support for policy-makers. A range of ecosystem services need to be valued and integrated into a resilient land-use strategy, including the introduction of non-monetary, physical-unit constraints on the use of particular services

    Time-course analysis following initial warm-up to inform pre-pitch entry preparations of soccer substitutes.

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    The purpose of this study was to investigate the time-course of decrements in physical performance following a pre-match warm-up in soccer players. Knowledge of this information could be used to inform re-warm-ups and pre-pitch entry practices of soccer substitutes. Data were collected over five sessions with 12 male youth professionals (15-17 yrs). Across the five sessions each player performed countermovement jumps (CMJ) and drop jumps (30 and 40 cm), pre-warm-up, immediately post-warm-up, and following 10-, 20-, 30-, 40-, and 50-minutes of inactivity. Physical performance was assessed by jump height and calculation of reactive strength index (RSI). Hierarchical generalized linear models (HGLMs) were fitted within a Bayesian framework to identify plausible time to achieve 10 to 50% decrements of the initial pre to post warm-up improvement. Mean improvements of 5.4 cm (95%CrI: 4.8 to 6.0), 0.24 ms-1 (95%CrI: 0.19 to 0.29), and 0.32 ms-1 (0.27 to 0.36) were obtained for the CMJ, and RSI measured from the 30 and 45 cm box, respectively. Decrements for all assessments were non-linear with the steepest rates of decline measured in the initial periods following warm-up. High probabilities were calculated (p ≥ 0.979) that up to 50% of the initial warm-up improvement for the CMJ would be lost between 20 and 30 minutes. The results of this study provide a guide for future research and practitioners managing the pre-pitch entry of soccer substitutes. It is suggested that practitioners consider and assess the effectiveness of exposing players to a re-warm-up between 20- and 30-minutes prior to pitch entry to maintain performance capabilities

    Encapsulated Energy-transfer Cassettes With Extremely Well Resolved Fluorescent Outputs

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    This paper concerns the development of water-compatible fluorescent imaging probes with tunable photonic properties that can be excited at a single wavelength. Bichromophoric cassettes 1a-1c consisting of a BODIPY donor and a cyanine acceptor were prepared using a simple synthetic route, and their photophysical properties were investigated. Upon excitation of the BODIPY moiety at 488 nm the excitation energy is transferred through an acetylene bridge to the cyanine dye acceptor, which emits light at approximately 600, 700, and 800 nm, i.e., with remarkable dispersions. This effect is facilitated by efficient energy transfer that gives a quasi-Stokes shift between 86 and 290 nm, opening a huge spectral window for imaging. The emissive properties of the cassettes depend on the energy-transfer (ET) mechanism: the faster the transfer, the more efficient it is. Measurements of rates of ET indicate that a through-bond ET takes place in the cassettes la and 1b that is 2 orders of magnitude faster than the classical through-space, Forster ET. In the case of cassette 1c, however, both mechanisms are possible, and the rate measurements do not allow us to discern between them. Thus, the cassettes 1a-1c are well suited for multiplexing experiments in biotechnological methods that involve a single laser excitation source. However, for widespread application of these probes, their solubility in aqueous media must be improved. Consequently, the probes were encapsulated in calcium phosphate/silicate nanoparticles (diameter ca. 22 nm) that are freely dispersible in water. This encapsulation process resulted in only minor changes in the photophysical properties of the cassettes. The system based on cassette la was chosen to probe how effectively these nanoparticles could be used to deliver the dyes into cells. Encapsulated cassette la permeated Clone 9 rat liver cells, where it localized in the mitochondria and fluoresced through the acceptor part, i.e., red. Overall, this paper reports readily accessible, cyanine-based through-bond ET cassettes that are lypophilic but can be encapsulated to form nanoparticles that disperse freely in water. These particles can be used to enter cells and to label organelles

    Prepontine Non-giant Neurons Drive Flexible Escape Behavior in Zebrafish

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    Many species execute ballistic escape reactions to avoid imminent danger. Despite fast reaction times, responses are often highly regulated, reflecting a trade-off between costly motor actions and perceived threat level. However, how sensory cues are integrated within premotor escape circuits remains poorly understood. Here, we show that in zebrafish, less precipitous threats elicit a delayed escape, characterized by flexible trajectories, which are driven by a cluster of 38 prepontine neurons that are completely separate from the fast escape pathway. Whereas neurons that initiate rapid escapes receive direct auditory input and drive motor neurons, input and output pathways for delayed escapes are indirect, facilitating integration of cross-modal sensory information. These results show that rapid decision-making in the escape system is enabled by parallel pathways for ballistic responses and flexible delayed actions and defines a neuronal substrate for hierarchical choice in the vertebrate nervous system
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