637 research outputs found

    Parental care in relation to offspring sex and mate attractiveness in the Blue Tit

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    The aim of this thesis is to determine whether differential allocation, sex biased care or differential sex-biased care occurs in blue tits. By videotaping feeding rates of blue tits and by determining the sex of offspring using molecular techniques, we can measure the amount of parental care by male and female blue tits in each sex of offspring. By measuring the UV-colouration of the parents, we are able to determine how much is invested in the total brood and in each offspring sex in relation to parental attractiveness.

    Elasticity Measurement in CaaS Environments - Extending the Existing BUNGEE Elasticity Benchmark to AWS\u27s Elastic Container Service

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    Rapid elasticity and automatic scaling are core concepts of most current cloud computing systems. Elasticity describes how well and how fast cloud systems adapt to increases and decreases in workload. In parallel, software architectures are moving towards employing containerised microservices running on systems managed by container orchestration platforms. Cloud users who employ such container-based systems may want to compare the elasticity of different systems or system settings to ensure rapid elasticity and maintain service level objectives while avoiding over-provisioning. Previous research has established a variety of metrics to measure elasticity. Some existing benchmark tools are designed to measure elasticity in ā€œInfrastructure as a Serviceā€ (IaaS) systems, but no research exists to date for measuring elasticity in systems based on containers and container orchestration. In this dissertation, an existing benchmark designed for IaaS systems, the BUNGEE benchmark developed at the University of WĆ¼rzburg, was extended to be applicable to Amazonā€™s Elastic Container Service, a container-based cloud system. An experiment was conducted to test if the extension of the BUNGEE benchmark described in this dissertation delivers reproducible results and is therefore valid. For validation, the crucial phase of the benchmark - the system analysis phase - was run 32 times. It was established with statistical tests if the results vary by more than the acceptable level. Results indicate that there is some amount of variability, but it does not exceed the acceptable level and is consistent with the amount of performance variability encountered by other researchers in Amazonā€™s cloud systems. Therefore, it is concluded that the BUNGEE benchmark is likely applicable to container-based cloud systems. However, some parameters and configuration settings specific to container orchestration systems were identified that could impede reproducibility of results and should be considered in future experiments

    The sensitivity of optimal railā€road terminal locations to intermodal freight costs variations

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    In the last decades, the market of goods became globalized, increasing international trade relations and the demand for long distance transportation. As a consequence of the larger distances traveled and of the containerization of goods, maritime transportation became more efficient and reliable. In the hinterland, intermodal (rail-road) freight transportation emerged as a competitive alternative to truck-only transportation. In one of its possible meanings, intermodal freight transportation is the multimodal chain of container-transportation services [1] that, e.g., brings containers from (or to) the seaport by barge or rail to (or from) an intermodal terminal in the hinterland from where they are shipped by truck to their final destination (or origin). This study focus on inland intermodal freight transport, in particular, on the railā€“truck transport of cargo containers in Belgium. This European country has a long rail system and in the last years has readapted this system in order to handle with containerized cargo. Since 2004, some rail-road terminals have been built and new intermodal services between the seaports of Belgium have been established. In addition, with the aim of promoting the modal share of intermodal rail-road transport, the federal government of Belgium started subsidizing part of the rail transport cost and of the transshipments costs at the rail-road terminals. With these investments the intermodal freight flows in Belgium have increased

    A new fasciocutaneous flap model identifies a critical role for endothelial Notch signaling in wound healing and flap survival.

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    Flap surgery is a common treatment for severe wounds and a major determinant of surgical outcome. Flap survival and healing depends on adaptation of the local flap vasculature. Using a novel and defined model of fasciocutaneous flap surgery, we demonstrate that the Notch ligand Delta-like 1 (Dll1), expressed in vascular endothelial cells, regulates flap arteriogenesis, inflammation and flap survival. Utilizing the stereotyped anatomy of dorsal skin arteries, ligation of the major vascular pedicle induced strong collateral vessel development by end-to-end anastomosis in wildtype mice, which supported flap perfusion recovery over time. In mice with heterozygous deletion of Dll1, collateral vessel formation was strongly impaired, resulting in aberrant vascularization and subsequent necrosis of the tissue. Furthermore, Dll1 deficient mice showed severe inflammation in the flap dominated by monocytes and macrophages. This process is controlled by endothelial Dll1 in vivo, since the results were recapitulated in mice with endothelial-specific deletion of Dll1. Thus, our model provides a platform to study vascular adaptation to flap surgery and molecular and cellular regulators influencing flap healing and survival


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    Designing unmanned aerial vehicle networks for biological material transportation

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    Unmanned Aerial Vehicles (UAVs) may solve, or at least reduce, the negative impacts of road transport such as pollution or congestion. This study deals with the UAVs network design problem for biomedical material transportation in line with the Drone4Care project. We begin with a PESTEL analysis to provide an overview of the various macro-environmental factors to be taken into consideration. To specify the objectives of the project and identify the internal and external factors that are favourable and unfavourable to achieving those objectives, a SWOT analysis is also performed. The elevated issues are translated into a number of quantifiable scenario elements, containing the most plausible upcoming events impacting the future of UAVs network for biological material. The developed location model is applied to the city of Brussels and periphery, with associated market in terms of biomedical products flows (blood units or medical samples transported between hospitals, laboratories, and blood transfusion centres) in the context of separate case studies of scenario-based analysis. The experiments show that if the return to the launching base is required, the total distance is greater than if this constraint is relaxed. This is a crucial point regarding limited range of UAVs. The use of charging stations is thus useful to extend the mission ranges and gain market share. The results also show the possibility of gradually implementing the bases, without requiring any major changes such as to close a base
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