3,948 research outputs found

    Longevity and mortality in Kennel Club registered dog breeds in the UK in 2014

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    Abstract Background The domestic dog is one of the most diverse mammalian species, exhibiting wide variations in morphology, behaviour and morbidity across breeds. Therefore, it is not unexpected that breeds should also exhibit variation in mortality and longevity. While shorter longevity per se may not necessarily be a welfare issue, a generally foreshortened lifespan in a breed that is accompanied by a high prevalence of a particular cause of death may reveal potentially serious welfare concerns and highlight scope to improve breed welfare. Survey data gathered directly from owners offer useful insights into canine longevity and mortality that can support the overall evidence base for welfare reforms within breeds. Results Mortality data on 5663 deceased dogs registered with the UK Kennel Club were collected from an owner-based survey. The most commonly reported causes of death were old age (13.8%), unspecified cancer (8.7%) and heart failure (4.9%); with 5.1% of deaths reported as unknown cause. Overall median age at death was 10.33 years (interquartile range: 7.17–12.83 years). Breeds varied widely in median longevity overall from the West Highland Terrier (12.71 years) to the Dobermann Pinscher (7.67 years). There was also wide variation in the prevalence of some common causes of death among breeds, and in median longevity across the causes of death. Conclusion Substantial variation in the median lifespan and the prominent causes of death exists across breeds. This study has identified some breeds with both a low median lifespan and also a high proportional mortality for one or more specific causes of death that should be considered as both potential welfare concerns as well as opportunities for improvement

    Large-scale survey to estimate the prevalence of disorders for 192 Kennel Club registered breeds

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    Abstract Background Pedigree or purebred dogs are often stated to have high prevalence of disorders which are commonly assumed to be a consequence of inbreeding and selection for exaggerated features. However, few studies empirically report and rank the prevalence of disorders across breeds although such data are of critical importance in the prioritisation of multiple health concerns, and to provide a baseline against which to explore changes over time. This paper reports an owner survey that gathered disorder information on Kennel Club registered pedigree dogs, regardless of whether these disorders received veterinary care. This study aimed to determine the prevalence of disorders among pedigree dogs overall and, where possible, determine any variation among breeds. Results This study included morbidity data on 43,005 live dogs registered with the Kennel Club. Just under two thirds of live dogs had no reported diseases/conditions. The most prevalent diseases/conditions overall were lipoma (4.3%; 95% confidence interval 4.13-4.52%), skin (cutaneous) cyst (3.1%; 2.94-3.27%) and hypersensitivity (allergic) skin disorder (2.7%; 2.52-2.82%). For the most common disorders in the most represented breeds, 90 significant differences between the within breed prevalence and the overall prevalence are reported. Conclusion The results from this study have added vital epidemiological data on disorders in UK dogs. It is anticipated that these results will contribute to the forthcoming Breed Health & Conservation Plans, a Kennel Club initiative aiming to assist in the identification and prioritisation of breeding selection objectives for health and provide advice to breeders/owners regarding steps that may be taken to minimise the risk of the disease/disorders. Future breed-specific studies are recommended to report more precise prevalence estimates within more breeds

    The sintering temperature effect on the shrinkage behavior of cobalt chromium alloy

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    Problem Statement: Co-Cr based alloys which is well known for its high Young’s modulus, fatigue strength, wear resistance and corrosion resistance is an important metallic bio�material. However, till date there are only two type of Co-Cr alloy which are the castable and wrought cobalt alloy. Powder Metallurgy route for cobalt is expected to give better result of Co-Cr alloy. The purpose of this research was mainly to study the sintering temperature effect to the shrinkage behavior of Cobalt Chromium (Co-Cr) alloy of the powder metallurgy route. Approach: Co-Cr was produced following P/M route under sintering temperature of 1000, 1100, 1200, 1300 and 1400oC. The sintering time was fixed at 60 min. Several tests has been conducted to determine this effect such as the rate of shrinkage measurement, the bulk density and porosity percentage measurement, compression and hardness tests and micro structural study. Result: From the study, it was found that the sintering temperature has caused the shrinkage of Co-Cr. The increasing of the sintering temperature has caused to the increasing of shrinkage of Co-Cr. This has resulted to the reduction of the pore volume and hence increased it density. In conjunction to that, the strength and the hardness of Co-Cr was increased. Conclusion: Therefore, it is hope that it will bring new view of powder metallurgy Co-Cr alloy as bio-material

    The sintering temperature effect on the shrinkage behavior of cobalt chromium alloy

    Get PDF
    Problem Statement: Co-Cr based alloys which is well known for its high Young’s modulus, fatigue strength, wear resistance and corrosion resistance is an important metallic bio�material. However, till date there are only two type of Co-Cr alloy which are the castable and wrought cobalt alloy. Powder Metallurgy route for cobalt is expected to give better result of Co-Cr alloy. The purpose of this research was mainly to study the sintering temperature effect to the shrinkage behavior of Cobalt Chromium (Co-Cr) alloy of the powder metallurgy route. Approach: Co-Cr was produced following P/M route under sintering temperature of 1000, 1100, 1200, 1300 and 1400oC. The sintering time was fixed at 60 min. Several tests has been conducted to determine this effect such as the rate of shrinkage measurement, the bulk density and porosity percentage measurement, compression and hardness tests and micro structural study. Result: From the study, it was found that the sintering temperature has caused the shrinkage of Co-Cr. The increasing of the sintering temperature has caused to the increasing of shrinkage of Co-Cr. This has resulted to the reduction of the pore volume and hence increased it density. In conjunction to that, the strength and the hardness of Co-Cr was increased. Conclusion: Therefore, it is hope that it will bring new view of powder metallurgy Co-Cr alloy as bio-material

    Enabling IoT Empowered Smart Lighting Solutions: A Communication Theoretic Perspective

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    The aim of this article is to explore the design space of the IoT empowered smart lighting systems from communication theoretic perspective. It is noted that traditional wired solution such as digital addressable lighting interface (DALI) need to be replaced altogether. The solutions proposing to replace just the end connections by wireless transceivers will not fit in the emerging IoT paradigm. Different architectural blocks of smart lighting systems are briefly described. The key enablers for each of these blocks, their evolution trajectories, existing challenges and possible pathways are briefly summarized. It is noted that the functionality of the building block of IoT based smart lighting system can be translated into an abstract reference architecture. A hirerichical networking architecture is proposed and different networking issues are discussed. Finally, a communication theoretic perspective for wireless interface selection is presented

    Drone Empowered Small Cellular Disaster Recovery Networks for Resilient Smart Cities

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    Resilient communication networks, which can continue operations even after a calamity, will be a central feature of future smart cities. Recent proliferation of drones propelled by the availability of cheap commodity hardware presents a new avenue for provisioning such networks. In particular, with the advent of Google’s Sky Bender and Facebook’s internet drone, drone empowered small cellular networks (DSCNs) are no longer fantasy. DSCNs are attractive solution for public safety networks because of swift deployment capability and intrinsic network reconfigurability. While DSCNs have received some attention in the recent past, the design space of such networks has not been extensively traversed. In particular, co-existence of such networks with an operational ground cellular network in a post-disaster situation has not been investigated. Moreover, design parameters such as optimal altitude and number of drone base stations, etc., as a function of destroyed base stations, propagation conditions, etc., have not been explored. In order to address these design issues, we present a comprehensive statistical framework which is developed from stochastic geometric perspective. We then employ the developed framework to investigate the impact of several parametric variations on the performance of the DSCNs. Without loss of any generality, in this article, the performance metric employed is coverage probability of a down-link mobile user. It is demonstrated that by intelligently selecting the number of drones and their corresponding altitudes, ground users coverage can be significantly enhanced. This is attained without incurring significant performance penalty to the mobile users which continue to be served from operating ground infrastructure

    Prospects for the sustainability of delivering the basic package of Health Services in Afghanistan: a stakeholder analysis

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    This study explored the readiness of stakeholders in Afghanistan for sustaining delivery of the Basic Package of Health Services (BPHS) without external technical and financial assistance. A stakeholder analysis was applied using qualitative methods. Fifteen stakeholders were purposively drawn from the Afghanistan ministries of public health and finance, political representatives, development partners, nonprofit organizations and public health experts. Data were collected through in-depth interviews with the stakeholders and desk review of pertinent documents. We found that sustainability of the BPHS in Afghanistan is questionable as stakeholders are sub optimally organized to come up with effective alternatives. Uneven ownership and divisive positioning are bottlenecks to the evolution of a realistic continuation plan. Those with the most significant influence are lukewarm, while those who are most supportive have the least influence. Sustainability needs to be tackled at the start in designing the BPHS rather than in the wake of eventual donor withdrawal

    On the Analysis of Device-to-Device Overlaid Cellular Networks in the Uplink under 3GPP Propagation Model

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    In this article we employ the third generation partnership project (3GPP) recommended path loss models for the analysis of cellular networks overlaid with D2D communication and channel inversion power control in the uplink. We characterize the coverage and average network throughput with the help of stochastic geometry. More specifically, we develop tractable expressions for the coverage in cellular and D2D modes. Our theoretical results differ significantly from previous work, which uses simple power law path loss models. The traditional methodology does not account for the presence of line-of-sight (LoS), non-line-of-sight (NLoS) and free space (FS) links. We demonstrate that such classification of links significantly impacts the inference which can be derived from the analysis for the design of overlaid D2D networks. In particular, we show that, contrary to the previous findings, the average throughput of the network does not saturate with the increase in the density of base stations (BS), but there exists an optimal mode selection threshold and BS density which maximizes the average throughput

    Energy Harvesting Empowered Cognitive Metro-cellular Networks

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    Harvesting energy from natural (solar, wind, vibration etc.) and synthesized (microwave power transfer) sources is envisioned as a key enabler for realizing green wireless networks. Energy efficient scheduling is one of the prime objectives of cognitive radio platforms. To that end, in this article, we present a comprehensive analytical framework to characterize the performance of a cognitive metro-cellular network empowered by solar energy harvesting. The proposed model considers both spatial and temporal dynamics of the energy field and the mobile user traffic. Channel uncertainties are also captured in terms of large scale path-loss and small-scale Rayleigh fading. A new metric called `energy outage probability' which characterizes the self-sustainable operation of the base stations under energy harvesting is proposed and quantified. It is shown that the energy outage probability is strongly coupled with the path-loss exponent, required quality-of-service, base station and user density. Moreover, the energy outage probability varies both on daily and yearly basis depending on the solar geometry. It is shown that even in winter time BSs can run for 10-15 hours without any purchase of energy from the power grid

    On the Analysis of Cellular Networks with Caching and Coordinated Device-to-Device Communication

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    In this paper, we develop a comprehensive analytical framework for cellular networks that are enhanced with coordinated device-to-device (D2D) communication, where the D2D devices are equipped with content caching capabilities. The base station (BS) coordinates the D2D communication by establishing a D2D link between the requesting user and the nearest D2D helper within the same cell if the latter contains the requested content, otherwise, the BS serves the user itself. The motivation behind restricting D2D pairs within a macro cell is to make coordinated D2D communication realizable as the BS can keep track of the content of the devices without the increased overhead of inter-BS coordination. This approach is similar to LTE direct, where D2D pairing is managed by the BS. We model the locations of BS and D2D helpers using a homogeneous Poisson point process (HPPP). The distribution of the distance between the tagged user and its neighboring D2D helper within the cell is derived using disk approximation for the Voronoi cell, which is shown to be reasonably accurate. We fully characterize the cellular and D2D coverage and the link spectral efficiency of such a network. Our results reveal that cache enabled D2D communication becomes more effective as the requesting user moves away from the BS and high performance gains can be achieved compared to conventional cellular networks, especially when the popularity distribution is skewed and most popular files are requested
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