496 research outputs found

    Linear filtering with fractional Brownian motion in the signal and observation processes

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    Integral equations for the mean-square estimate are obtained for the linear filtering problem, in which the noise generating the signal is a fractional Brownian motion with Hurst index h∈(3/4,1) and the noise in the observation process includes a fractional Brownian motion as well as a Wiener process. AMS subject classifications: 93E11, 60G20, 60G35

    The Role of the Liver X Receptor (LXR) in the Fetal Programming of Hepatic Gluconeogenesis

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    Chronic diseases such as type 2 diabetes and the Metabolic Syndrome create enormous burdens on society. Epidemiological studies now strongly implicate intrauterine growth restriction (IUGR) for increasing the risk of developing chronic diseases later on in life. However, the molecular mechanisms underlying how IUGR leads to the increased susceptibility to these metabolic diseases in adulthood is not well understood. The Liver-X-Receptor (LXR) is a nuclear receptor involved in cholesterol, glucose, and lipid metabolism. LXR acts to decrease gluconeogenesis through repression of glucose-6-phosphatase(G6Pase), phosphoenolpyruvate carboxykinase(PEPCK), and 11β-hydroxysteroid dehydrogenase type-1(11β-HSD1). Using a well-characterized model of maternal protein restriction in rats, this study attempts to elucidate the role of LXR in the long-term programming of impaired glucose homeostasis. It was discovered that altered expression of LXR during the gestational and neonatal period predisposes the fetus to impaired glucose tolerance in adult life through LXR-mediated activation of the gluconeogenic genes G6Pase, PEPCK, and 11β-HSD1

    Possible Used Fuel Management Options For A Single Reactor Utility

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    Used nuclear fuel generated by the operation of Nuclear Power Plants (NPP) needs to be managed in a safe, responsible and effective way. Whereas utilities managing several NPP can implement large scale used fuel management operations, a single reactor utility will chose solutions adapted for relatively low amount of used fuel. There are currently two different approaches for managing used fuel: Open fuel cycle, or “once-through” strategy, where used fuel is considered to be waste and disposed of after wet or dry interim storage following in-reactor use; Closed fuel cycle, or “recycling” strategy, where used fuel is considered as valuable material as it mainly contains reusable uranium and plutonium and thus recycled; such strategy can be implemented directly after in-reactor use without interim storage step and can also be put in place after interim storage; by treating used fuel, 96% of the nuclear material is recovered and recycled as Mixed OXide (MOX) fuel and Enriched Reprocessed Uranium (ERU) fuel; the remaining 4% of non-recyclable material, as well as cladding and structural elements of fuel assemblies, are packaged for final disposal. In addition, long term interim storage of used fuel has been retained by some states until decision is made for one or the other of the two available options, keeping in mind that interim storage, even long term, is a waiting solution and not a sustainable one. For all options, disposal is the final radioactive waste management step: either direct disposal of used fuel or disposal of final residual waste remaining after used fuel treatment. The purpose of the paper is to present the possible used fuel management options for a single reactor utility, clarifying advantages and drawbacks of each of them according to following criteria: safety, security, sustainable development, environment protection, non-proliferation, public acceptance, economy

    Per os infectivity of white spot syndrome virus (WSSV) in white-legged shrimp (Litopenaeus vannamei) and role of peritrophic membrane

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    As earlier observations on peroral infectivity of WSSV in white-legged shrimp are conflicting, here, a standardized peroral intubation technique was used to examine (i) the role of the physical composition of the viral inoculum and (ii) the barrier function of the PM. In a first experiment, the infectivity of a WSSV stock was compared by determining the SID50 by intramuscular injection, peroral inoculation or via feeding. The following titers were obtained: 108.77 SID50/g by intramuscular injection, 10(1.23) SID50/g by peroral inoculation and 100.73 SID50/g by feeding. These results demonstrated that 10(7.54)-10(8.03) infectious virus is needed to infect shrimp by peroral inoculation and via feeding. Next, it was examined if damage of the PM may increase the susceptibility for WSSV by peroral route. The infectivity of a virus stock was tested upon peroral inoculation of shrimp with and without removal of the PM and compared with the infectivity upon intramuscular inoculation. The virus titers obtained upon intramuscular injection and peroral inoculation of shrimp with and without PM were 10(8.63), 10(1.13) and 10(1.53) SID50/mL, respectively. This experiment confirmed the need of 10(7.1)-10(7.5) infectious virus to infect shrimp via peroral route and showed that the removal of the PM slightly but not significantly (p > 0.05) facilitated the infection of shrimp. This study indicated that WSSV contaminated feed is poorly infectious via peroral route, whereas it is highly infectious when injected into shrimp. The PM plays a minor role as internal barrier of shrimp against WSSV infection

    Micro-simulation of Car Drivers’ Movements at Parking Lots

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    AbstractDrivers’ movements across or within parking facilities contribute to various problems, i.e., congestion, safety, and environmental effects. Micro-simulation can help to increase the understanding of drivers’ movements and their effects on parking management. This study aims to develop a multi agent-based simulation tool to demonstrate its capability of studying driver movements across parking lots. The program was constructed using the multi-agent modeling environment NetLogo. The developed simulation tool allows to adjust features of the parking facilities. Additionally, vehicle travel time and parking occupancy indicators were integrated to investigate the efficiency of the parking

    Possible Used Fuel Management Options For A Single Reactor Utility

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    Used nuclear fuel generated by the operation of Nuclear Power Plants (NPP) needs to be managed in a safe, responsible and effective way. Whereas utilities managing several NPP can implement large scale used fuel management operations, a single reactor utility will chose solutions adapted for relatively low amount of used fuel. There are currently two different approaches for managing used fuel: Open fuel cycle, or “once-through” strategy, where used fuel is considered to be waste and disposed of after wet or dry interim storage following in-reactor use; Closed fuel cycle, or “recycling” strategy, where used fuel is considered as valuable material as it mainly contains reusable uranium and plutonium and thus recycled; such strategy can be implemented directly after in-reactor use without interim storage step and can also be put in place after interim storage; by treating used fuel, 96% of the nuclear material is recovered and recycled as Mixed OXide (MOX) fuel and Enriched Reprocessed Uranium (ERU) fuel; the remaining 4% of non-recyclable material, as well as cladding and structural elements of fuel assemblies, are packaged for final disposal. In addition, long term interim storage of used fuel has been retained by some states until decision is made for one or the other of the two available options, keeping in mind that interim storage, even long term, is a waiting solution and not a sustainable one. For all options, disposal is the final radioactive waste management step: either direct disposal of used fuel or disposal of final residual waste remaining after used fuel treatment. The purpose of the paper is to present the possible used fuel management options for a single reactor utility, clarifying advantages and drawbacks of each of them according to following criteria: safety, security, sustainable development, environment protection, non-proliferation, public acceptance, economy

    Virtual Reality and Creativity: Lessons Learned from a Luminaire Design Project

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    Current research in design education showed that experiencing virtual reality (VR) in learning led to higher creativity in students. However, some studies showed only a partial impact of VR on student creativity. Using video data analysis (VDA), the authors examined a half-an-hour excerpt of the recorded VR learning experience from a previous study on interior design students (n=13). The authors sought an explanation for the partial impacts of VR on students’ creativity via observing and interpreting one participant’s (a) interaction with VR and (b) the context of the virtual environment. VDA analysis results indicated that the implemented VR technology was intuitive for a fundamental learner yet required time and practice to gain advanced skills. Exploration time was also necessary for students to fully demonstrate the novel, resolution, and style aspects of creativity in their works. The implication is that the partial impact of VR on creativity found in the previous study might be due to the constraints of time and expertise of students (i.e., learn and explore), not VR technology per se. Educators and institutions wishing to include VR in their curricula should allow students ample time and access to VR applications and headsets to practice and sharpen their expertise

    The smallest macroscale tensile test - a model to describe constrained flow at the microscale

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    This work addresses the strain response and plastic flow behavior of grain boundary or interface containing materials during small scale mechanical testing. We introduce a set of geometric criteria allowing us to constrain a sample to obtain macroscopic-like flow behavior on a microscale test, as shown in Figure 1. Furthermore, the featured parameter, the blocked volume ratio, provided a new description of plasticity of microscale tensile samples in a constrained volume due to external interfaces such as coating and grain boundaries. The proposed description was experimentally validated with different Ni-based materials and different constraints (grain boundary and coating interfaces). The developed theory would open new research avenues in establishing the connection between microscale response to bulk properties as follows: Please click Additional Files below to see the full abstract

    The costs of traumatic brain injury due to motorcycle accidents in Hanoi, Vietnam

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    Background: Road traffic accidents are the leading cause of fatal and non-fatal injuries in Vietnam. The purpose of this study is to estimate the costs, in the first year post-injury, of non-fatal traumatic brain injury (TBI) in motorcycle users not wearing helmets in Hanoi, Vietnam. The costs are calculated from the perspective of the injured patients and their families, and include quantification of direct, indirect and intangible costs, using years lost due to disability as a proxy. Methods: The study was a retrospective cross-sectional study. Data on treatment and rehabilitation costs, employment and support were obtained from patients and their families using a structured questionnaire and The European Quality of Life instrument (EQ6D). Results: Thirty-five patients and their families were interviewed. On average, patients with severe, moderate and minor TBI incurred direct costs at USD 2,365, USD 1,390 and USD 849, with time lost for normal activities averaging 54 weeks, 26 weeks and 17 weeks and years lived with disability (YLD) of 0.46, 0.25 and 0.15 year, respectively. Conclusion: All three component costs of TBI were high; the direct cost accounted for the largest proportion, with costs rising with the severity of TBI. The results suggest that the burden of TBI can be catastrophic for families because of high direct costs, significant time off work for patients and caregivers, and impact on health-related quality of life. Further research is warranted to explore the actual social and economic benefits of mandatory helmet use
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