3,471 research outputs found
Effects of radiation on charge-coupled devices
The effects of 1 MeV electron irradiation upon the performance of two phase, polysilicon aluminum gate CCDs are reported. Both n- and p-surface channel and n-buried channel devices are investigated using 64- and 128-stage line arrays. Characteristics measured as a function of radiation dose include: Transfer inefficiency, threshold voltage, field effect mobility, interface state density, full well signal level and dark current. Surface channel devices are found to degrade considerably at less than 10 to the 5th power rads (Si) due to the large increase in fast interface state density caused by radiation. Buried channel devices maintain efficient operation to the highest dose levels used
Management Strategies Of Non-Profit Community Sport Facilities In An Era Of Austerity
Research Question: This qualitative research explores the impact of austerity on community sport facilities across England (United Kingdom), drawing upon resource dependence theory (RDT) embedded within network theory. Research Methods: In-depth semi-structured interview data were collected from 24 stakeholders related to community sport facilities (n=12 facility managers, n=6 regional grant managers, n=6 national funders both third sector and corporate). The qualitative data were thematically analysed to understand the impact of austerity on how community sport facilities managed their organisations and operations. Results and Findings: The findings from this research offer insight into the challenges that community sport facilities are encountering which have resulted from austerity, and a shrinking of the funding from central Government to local public services. Furthermore, different community sport facilities have navigated these challenges to maintain sustainability, essentially through adapting network structure and through income dynamism. In addition, using a network theory approach alongside RDT within a sporting context, has allowed us to address issues on how network flow and structure impact sustainability and operations within and between organisations. Implications: The article offers managerial recommendations for community sport facility managers, practitioners and policy makers who operate in times of fiscal constraint. It recommends that future sport research utilises and applies both RDT and network theory to examine these changes and the subsequent management strategies adopted to overcome the associated challenges of fiscal constraint
An Inexpensive Flying Robot Design for Embodied Robotics Research
Flying insects are capable of a wide-range of flight and cognitive behaviors which are not currently understood. The replication of these capabilities is of interest to miniaturized robotics, because they share similar size, weight, and energy constraints. Currently, embodiment of insect behavior is primarily done on ground robots which utilize simplistic sensors and have different constraints to flying insects. This limits how much progress can be made on understanding how biological systems fundamentally work. To address this gap, we have developed an inexpensive robotic solution in the form of a quadcopter aptly named BeeBot. Our work shows that BeeBot can support the necessary payload to replicate the sensing capabilities which are vital to bees' flight navigation, including chemical sensing and a wide visual field-of-view. BeeBot is controlled wirelessly in order to process this sensor data off-board; for example, in neural networks. Our results demonstrate the suitability of the proposed approach for further study of the development of navigation algorithms and of embodiment of insect cognition
An analytical and experimental assessment of flexible road ironwork support structures
This paper describes work undertaken to investigate the mechanical performance of road ironwork installations in highways, concentrating on the chamber construction. The principal aim was to provide the background research which would allow improved designs to be developed to reduce the incidence of failures through improvements to the structural continuity between the installation and the surrounding pavement. In doing this, recycled polymeric construction materials (Jig Brix) were studied with a view to including them in future designs and specifications. This paper concentrates on the Finite Element (FE) analysis of traditional (masonry) and flexible road ironwork structures incorporating Jig Brix. The global and local buckling capacity of the Jig Brix elements was investigated and results compared well with laboratory measurements. FE models have also been developed for full-scale traditional (masonry) and flexible installations in a surrounding flexible (asphalt) pavement structure. Predictions of response to wheel loading were compared with full-scale laboratory measurements. Good agreement was achieved with the traditional (masonry) construction but poorer agreement for the flexible construction. Predictions from the FE model indicated that the use of flexible elements significantly reduces the tensile horizontal strain on the surface of the surrounding asphaltic material which is likely to reduce the incidence of surface cracking
Evaluating the integrity of forested riparian buffers over a large area using LiDAR data and Google Earth Engine
Spatial and temporal changes in the land cover affect water quality in the streams and other water bodies. Stream riparian areas are increasingly relevant as the human modification of the landscape continue unabated. The objectives of this study were to: (1) determine the classes and the distribution of land cover in stream riparian areas; (2) examine the accuracy of the existing land cover data National Land Cover Database (NLCD) using high-resolution imagery NAIIP and LiDAR data; and (3) evaluate the integrity of forested riparian buffers areas in the Lower Savannah River basin. The land cover map was produced using a Support Vector Machine (SVM) algorithm supervised classification through the cloud-based Google Earth Engine platform with an overall accuracy assessment of 83.66%. LiDAR data analysis were implemented using ArcGIS 10.6. The result of this study demonstrates that LiDAR data can be used to accurately map the vegetation width, height and canopy cover within the riparian buffer over wide areas to support ecological-based management. It is also highlighted that the open-access imagery and the efficient geospatial analysis GEE provides a reliable methodology to remotely monitor forest cover and land use in the riparian buffer areas
Weak Interaction Studies with 6He
The 6He nucleus is an ideal candidate to study the weak interaction. To this
end we have built a high-intensity source of 6He delivering ~10^10 atoms/s to
experiments. Taking full advantage of that available intensity we have
performed a high-precision measurement of the 6He half-life that directly
probes the axial part of the nuclear Hamiltonian. Currently, we are preparing a
measurement of the beta-neutrino angular correlation in 6He beta decay that
will allow to search for new physics beyond the Standard Model in the form of
tensor currents.Comment: 5 pages, 4 figures, proceedings for the Eleventh Conference on the
Intersections of Particle and Nuclear Physics (CIPANP 2012
Football, sport and the development of young people’s life skills
© 2016 Informa UK Limited, trading as Taylor & Francis Group. The development of life skills has been associated with participation in sport, football and other physical activities. A factor in enabling this ambition to be realized is the actions and behaviours of sports coaches. Drawing on the concept of positive youth development through sport, the first part of this paper considers the types of environments coaches need to create in order for players to develop life skills. The second part of this paper discusses formal coach education and its role in developing coaches’ knowledge of life skills development. The third and final section of this paper offers an alternative explanation of how people’s exposure to certain social contexts results in the development of life skills. A review of literature in these areas reveals that the role sport and football has played in players’ development of life skills is unclear and in need of future research attention
Reproducibility of parameters of postocclusive reactive hyperemia measured by diffuse optical tomography
The application of near-infrared spectroscopy (NIRS) to assess microvascular function has shown promising results. An important limitation when using a single source-detector pair, however, is the lack of depth sensitivity. Diffuse optical tomography (DOT) overcomes this limitation using an array of sources and detectors that allow the reconstruction of volumetric hemodynamic changes. This study compares the key parameters of postocclusive reactive hyperemia measured in the forearm using standard NIRS and DOT. We show that while the mean parameter values are similar for the two techniques, DOT achieves much better reproducibility, as measured by the intraclass correlation coefficient (ICC). We show that DOT achieves high reproducibility for muscle oxygen consumption (ICC: 0.99), time to maximal HbO2HbO2 (ICC: 0.94), maximal HbO2HbO2 (ICC: 0.99), and time to maximal HbT (ICC: 0.99). Absolute reproducibility as measured by the standard error of measurement is consistently smaller and close to zero (ideal value) across all parameters measured by DOT compared to NIRS. We conclude that DOT provides a more robust characterization of the reactive hyperemic response and show how the availability of volumetric hemodynamic changes allows the identification of areas of temporal consistency, which could help characterize more precisely the microvasculature
Role of Predicted Metalloprotease Motif of Jab1/Csn5 in Cleavage of Nedd8 from Cul1
COP9 signalosome (CSN) cleaves the ubiquitin-like protein Nedd8 from the Cul1 subunit of SCF ubiquitin ligases. The Jab1/MPN domain metalloenzyme (JAMM) motif in the Jab1/Csn5 subunit was found to underlie CSN's Nedd8 isopeptidase activity. JAMM is found in proteins from archaea, bacteria, and eukaryotes, including the Rpn11 subunit of the 26S proteasome. Metal chelators and point mutations within JAMM abolished CSN-dependent cleavage of Nedd8 from Cul1, yet had little effect on CSN complex assembly. Optimal SCF activity in yeast and both viability and proper photoreceptor cell (R cell) development in Drosophila melanogaster required an intact Csn5 JAMM domain. We propose that JAMM isopeptidases play important roles in a variety of physiological pathways
The impact of CHIP premium increases on insurance outcomes among CHIP eligible children
Background: Within the United States, public insurance premiums are used both to discourage private health policy holders from dropping coverage and to reduce state budget costs. Prior research suggests that the odds of having private coverage and being uninsured increase with increases in public insurance premiums. The aim of this paper is to test effects of Children's Health Insurance Program (CHIP) premium increases on public insurance, private insurance, and uninsurance rates. Methods: The fact that families just below and above a state-specific income cut-off are likely very similar in terms of observable and unobservable characteristics except the premium contribution provides a natural experiment for estimating the effect of premium increases. Using 2003 Medical Expenditure Panel Survey (MEPS) merged with CHIP premiums, we compare health insurance outcomes for CHIP eligible children as of January 2003 in states with a two-tier premium structure using a cross-sectional regression discontinuity methodology. We use difference-in-differences analysis to compare longitudinal insurance outcomes by December 2003. Results: Higher CHIP premiums are associated with higher likelihood of private insurance. Disenrollment from CHIP in response to premium increases over time does not increase the uninsurance rate. Conclusions: When faced with higher CHIP premiums, private health insurance may be a preferable alternative for CHIP eligible families with higher incomes. Therefore, competition in the insurance exchanges being formed under the Affordable Care Act could enhance choice
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