18,669 research outputs found

    FM contract relationships: from mobilisation to sustainable partnership

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    Purpose / theory Outsourcing is a fundamental business model for the Facilities Management (FM) industry. To enable sustained mutual success the parties involved must seek to understand the unique, socially constructed, and often highly complex situational realities of the organisational ecologies they are engaged in. The FM industry can unlock improved performance and strategic credibility through an appreciation of the need for different conversations. Design / methodology / approach Findings from two recent cases are considered. Data from two different client-contractor relationship situations was collected utilising a critical ethnographic research methodology; a phenomenological paradigm that acknowledges knowledge as socially constructed through language. A variant on Scott-Morgan‟s unwritten-rules coding method was used to analyse the data and justify the prevalent themes and issues presented. Findings Findings include the role of perceptions and assertions in the construction of social realities, change management implications, and how these impact on the traditional view of the client/contractor relationship. Ethnographic findings are typically context specific, therefore generalisations must be carefully considered. The key findings are however substantiated by existing FM outsourcing literature. Originality / value Highlights the practical importance of seeking to understand socially embedded realities for improved FM contract performance. Considers the human resource element of change via FM outsourcing. Takes a social constructivist approach to organisational sense-making. Uses examples from focused, critical ethnographies to explore existing FM contracting dynamics. Qualitative investigations into related organisational circumstances are encouraged to further develop an evidence base

    Energy-Efficient Transmission Scheduling with Strict Underflow Constraints

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    We consider a single source transmitting data to one or more receivers/users over a shared wireless channel. Due to random fading, the wireless channel conditions vary with time and from user to user. Each user has a buffer to store received packets before they are drained. At each time step, the source determines how much power to use for transmission to each user. The source's objective is to allocate power in a manner that minimizes an expected cost measure, while satisfying strict buffer underflow constraints and a total power constraint in each slot. The expected cost measure is composed of costs associated with power consumption from transmission and packet holding costs. The primary application motivating this problem is wireless media streaming. For this application, the buffer underflow constraints prevent the user buffers from emptying, so as to maintain playout quality. In the case of a single user with linear power-rate curves, we show that a modified base-stock policy is optimal under the finite horizon, infinite horizon discounted, and infinite horizon average expected cost criteria. For a single user with piecewise-linear convex power-rate curves, we show that a finite generalized base-stock policy is optimal under all three expected cost criteria. We also present the sequences of critical numbers that complete the characterization of the optimal control laws in each of these cases when some additional technical conditions are satisfied. We then analyze the structure of the optimal policy for the case of two users. We conclude with a discussion of methods to identify implementable near-optimal policies for the most general case of M users.Comment: 109 pages, 11 pdf figures, template.tex is main file. We have significantly revised the paper from version 1. Additions include the case of a single receiver with piecewise-linear convex power-rate curves, the case of two receivers, and the infinite horizon average expected cost proble

    Video Evidence That London Infants Can Resettle Themselves Back to Sleep After Waking in the Night, as well as Sleep for Long Periods, by 3 Months of Age

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    Objective: Most infants become settled at night by 3 months of age, whereas infants not settled by 5 months are likely to have long-term sleep-waking problems. We assessed whether normal infant development in the first 3 months involves increasing sleep-period length or the ability to resettle autonomously after waking in the night. Methods: One hundred one infants were assessed at 5 weeks and 3 months of age using nighttime infrared video recordings and parental questionnaires. Results: The clearest development was in sleep length; 45% of infants slept continuously for 5 hours or more at night at 3 months compared with 10% at 5 weeks. In addition, around a quarter of infants woke and resettled themselves back to sleep in the night at each age. Autonomous resettling at 5 weeks predicted prolonged sleeping at 3 months suggesting it may be a developmental precursor. Infants reported by parents to sleep for a period of 5 hours or more included infants who resettled themselves and those with long sleeps. Three-month olds fed solely breast milk were as likely to self-resettle or have long sleep bouts as infants fed formula or mixed breast and formula milk. Conclusions: Infants are capable of resettling themselves back to sleep in the first 3 months of age; both autonomous resettling and prolonged sleeping are involved in “sleeping through the night” at an early age. Findings indicate the need for physiological studies of how arousal, waking, and resettling develop into sustained sleeping and of how environmental factors support these endogenous and behavioral processes

    Oscillatory dynamics in a model of vascular tumour growth -- implications for chemotherapy

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    Background\ud \ud Investigations of solid tumours suggest that vessel occlusion may occur when increased pressure from the tumour mass is exerted on the vessel walls. Since immature vessels are frequently found in tumours and may be particularly sensitive, such occlusion may impair tumour blood flow and have a negative impact on therapeutic outcome. In order to study the effects that occlusion may have on tumour growth patterns and therapeutic response, in this paper we develop and investigate a continuum model of vascular tumour growth.\ud Results\ud \ud By analysing a spatially uniform submodel, we identify regions of parameter space in which the combination of tumour cell proliferation and vessel occlusion give rise to sustained temporal oscillations in the tumour cell population and in the vessel density. Alternatively, if the vessels are assumed to be less prone to collapse, stable steady state solutions are observed. When spatial effects are considered, the pattern of tumour invasion depends on the dynamics of the spatially uniform submodel. If the submodel predicts a stable steady state, then steady travelling waves are observed in the full model, and the system evolves to the same stable steady state behind the invading front. When the submodel yields oscillatory behaviour, the full model produces periodic travelling waves. The stability of the waves (which can be predicted by approximating the system as one of λ-ω type) dictates whether the waves develop into regular or irregular spatio-temporal oscillations. Simulations of chemotherapy reveal that treatment outcome depends crucially on the underlying tumour growth dynamics. In particular, if the dynamics are oscillatory, then therapeutic efficacy is difficult to assess since the fluctuations in the size of the tumour cell population are enhanced, compared to untreated controls.\ud Conclusions\ud \ud We have developed a mathematical model of vascular tumour growth formulated as a system of partial differential equations (PDEs). Employing a combination of numerical and analytical techniques, we demonstrate how the spatio-temporal dynamics of the untreated tumour may influence its response to chemotherapy.\ud Reviewers\ud \ud This manuscript was reviewed by Professor Zvia Agur and Professor Marek Kimmel

    Factors affecting nitrate distribution in shallow groundwater under a beef farm in South Eastern Ireland

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    peer-reviewedGroundwater contamination was characterised using a methodology which combines shallow groundwater geochemistry data from 17 piezometers over a 2 yr period in a statistical framework and hydrogeological techniques. Nitrate–N (NO3-N) contaminant mass flux was calculated across three control planes (rows of piezometers) in six isolated plots. Results showed natural attenuation occurs on site although the method does not directly differentiate between dilution and denitrification. It was further investigated whether NO3-N concentration in shallow groundwater (<5 m below ground level) generated from an agricultural point source on a 4.2 ha site on a beef farm in SE Ireland could be predicted from saturated hydraulic conductivity (Ksat) measurements, ground elevation (m Above Ordnance Datum), elevation of groundwater sampling (screen opening interval) (m AOD) and distance from a dirty water point pollution source. Tobit regression, using a background concentration threshold of 2.6 mg NO3-N L−1 showed, when assessed individually in a step wise procedure, Ksat was significantly related to groundwater NO3-N concentration. Distance of the point dirty water pollution source becomes significant when included with Ksat in the model. The model relationships show areas with higher Ksat values have less time for denitrification to occur, whereas lower Ksat values allow denitrification to occur. Areas with higher permeability transport greater NO3-N fluxes to ground and surface waters. When the distribution of Cl− was examined by the model, Ksat and ground elevation had the most explanatory power but Ksat was not significant pointing to dilution having an effect. Areas with low NO3 concentration and unaffected Cl− concentration points to denitrification, low NO3 concentration and low Cl− chloride concentration points to dilution and combining these findings allows areas of denitrification and dilution to be inferred. The effect of denitrification is further supported as mean groundwater NO3-N was significantly (P < 0.05) related to groundwater N2/Ar ratio, redox potential (Eh), dissolved O2 and N2 and was close to being significant with N2O (P = 0.08). Calculating contaminant mass flux across more than one control plane is a useful tool to monitor natural attenuation. This tool allows the identification of hot spot areas where intervention other than natural attenuation may be needed to protect receptors.Research Stimulus Fund, Department of Agriculture Fisheries and Food (Ireland

    Sub-post offices and high street revitalisation: lessons from the experience of grant assistance to sub-post offices in deprived urban areas of the UK

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    Post Offices (POs) are essential service providers within deprived urban areas. This paper explores some lessons from the impact of grant assistance to sub-post offices (SPOs) in deprived urban areas of England and Scotland which are relevant to contemporary policy initiatives to revive high streets. Utilising longitudinal data to explore whether government grant assistance has made a difference in enabling the survival and development of assisted SPOs, it also considers their role in maintaining and developing shops and services in deprived urban neighbourhoods. The inter-relationship of SPOs with their local economies and communities is explored, including external influences such as competition and complementarity and internal influences relating to the evolving role of SPOs in the early 21st century. A central theme is the apparent paradox between the UK Government’s desire to maintain SPOs as essential service providers and catalysts for other ‘high street’ services within deprived urban areas, whilst opening their core services up to increasing levels of competition. Key Words: Post Offices, Retail, High Street Services, Urban, Regeneration, Deprivatio
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