Station keeping of high power communication satellites

Station keeping of high power communication satellite

Low cost tracking Navaids error model verification

Features and characteristics of the tracking navaids (Microwave Scanning Beam Landing System, Radar Altimeter, Tacan, rendezvous radar and one way Doppler extracter) were investigated. From the investigation, a set of specifications were developed for building equipment to verify the error model of the tracking navaids. Breadboard verification equipment (BVE) was built for the Microwave Scanning Beam Landing System and the radar altimeter. The breadboard verification equipment generates signals to the tracking navaids which simulate the space shuttles trajectory in the terminal area. The BVE simulates sources of navaids error by generating pseudorandom perturbations on the navaids signals. Differences between the trajectory value and the navaid derived values are taped and form the basis for the navaids error model

Titanium honeycomb structure

A brazed titanium honeycomb sandwich system for supersonic transport wing cover panels provides the most efficient structure spanwise, chordwise, and loadwise. Flutter testing shows that high wing stiffness is most efficient in a sandwich structure. This structure also provides good thermal insulation if liquid fuel is carried in direct contact with the wing structure in integral fuel tanks

Oxidative DNA damage in mild cognitive impairment and late-stage Alzheimer's disease

Increasing evidence supports a role for oxidative DNA damage in aging and several neurodegenerative diseases including Alzheimer's disease (AD). Attack of DNA by reactive oxygen species (ROS), particularly hydroxyl radicals, can lead to strand breaks, DNA–DNA and DNA–protein cross-linking, and formation of at least 20 modified bases adducts. In addition, α,β-unsaturated aldehydic by-products of lipid peroxidation including 4-hydroxynonenal and acrolein can interact with DNA bases leading to the formation of bulky exocyclic adducts. Modification of DNA bases by direct interaction with ROS or aldehydes can lead to mutations and altered protein synthesis. Several studies of DNA base adducts in late-stage AD (LAD) brain show elevations of 8-hydroxyguanine (8-OHG), 8-hydroxyadenine (8-OHA), 5-hydroxycytosine (5-OHC), and 5-hydroxyuracil, a chemical degradation product of cytosine, in both nuclear and mitochondrial DNA (mtDNA) isolated from vulnerable regions of LAD brain compared to age-matched normal control subjects. Previous studies also show elevations of acrolein/guanine adducts in the hippocampus of LAD subjects compared to age-matched controls. In addition, studies of base excision repair show a decline in repair of 8-OHG in vulnerable regions of LAD brain. Our recent studies show elevated 8-OHG, 8-OHA, and 5,6-diamino-5-formamidopyrimidine in both nuclear and mtDNA isolated from vulnerable brain regions in amnestic mild cognitive impairment, the earliest clinical manifestation of AD, suggesting that oxidative DNA damage is an early event in AD and is not merely a secondary phenomenon

Oxidative DNA Damage in Mild Cognitive Impairment and Late-Stage Alzheimer\u27s Disease

Increasing evidence supports a role for oxidative DNA damage in aging and several neurodegenerative diseases including Alzheimer\u27s disease (AD). Attack of DNA by reactive oxygen species (ROS), particularly hydroxyl radicals, can lead to strand breaks, DNA–DNA and DNA–protein cross-linking, and formation of at least 20 modified bases adducts. In addition, α,β-unsaturated aldehydic by-products of lipid peroxidation including 4-hydroxynonenal and acrolein can interact with DNA bases leading to the formation of bulky exocyclic adducts. Modification of DNA bases by direct interaction with ROS or aldehydes can lead to mutations and altered protein synthesis. Several studies of DNA base adducts in late-stage AD (LAD) brain show elevations of 8-hydroxyguanine (8-OHG), 8-hydroxyadenine (8-OHA), 5-hydroxycytosine (5-OHC), and 5-hydroxyuracil, a chemical degradation product of cytosine, in both nuclear and mitochondrial DNA (mtDNA) isolated from vulnerable regions of LAD brain compared to age-matched normal control subjects. Previous studies also show elevations of acrolein/guanine adducts in the hippocampus of LAD subjects compared to age-matched controls. In addition, studies of base excision repair show a decline in repair of 8-OHG in vulnerable regions of LAD brain. Our recent studies show elevated 8-OHG, 8-OHA, and 5,6-diamino-5-formamidopyrimidine in both nuclear and mtDNA isolated from vulnerable brain regions in amnestic mild cognitive impairment, the earliest clinical manifestation of AD, suggesting that oxidative DNA damage is an early event in AD and is not merely a secondary phenomenon

State-of-the-art survey of dissimilar metal joining by solid state welding

State-of-the-art of dissimilar metal joining by solid state diffusion bonding and roll and press welding, emphasizing stainless steel and aluminum allo

What are the health and well-being impacts of community gardening for adults and children: a mixed method systematic review protocol

Background Community gardening is defined by its shared nature; gardeners work collectively to manage a garden for shared benefit. Although communal gardening activities, and recognition of their perceived benefits have a long history, it is in recent years that interest has developed in assessing the potential of the approach to address many of the threats to health and wellbeing faced by global populations. Community gardening may address chronic and non-communicable disease through the provision of opportunities for physical activity, improved nutrition and reduced stress. Participation in the gardening activities may improve wellbeing through increased social contact, culturally valued activities and mitigation of food poverty. The benefits of community gardening are argued to extend beyond the participants themselves through more coherent and cohesive communities, improved physical environments and the sharing of the products of the labour. While there are many claims made and an emerging body of research, no previous systematic review has sought to identify and synthesise the evidence in a global context. Methods The objectives of the mixed method systematic review are to understand the health and wellbeing impacts of active participation in community gardening. Both quantitative and qualitative evidence will be sought using a broad and diverse search strategy to address the four review questions: 1) does active involvement in community gardening lead to improved health or wellbeing; 2) if so, how does active involvement in community gardening affect health and wellbeing; 3) are there different impacts for different population groups (for instance according to age, socio-economic status or sex); and 4) do different types of community gardening (for example producing vegetables or a flower garden) or in different contexts have different types of impacts? A theoretical framework, informed by an initial theory of change model, will illustrate the outcomes of participation and any mechanisms of action (i.e. how such impacts are achieved). The synthesis will be sensitive to factors which may affect the impacts, such as the context of the activities, the demographics of participants, and the implementation and specifics of the community gardening interventions.European Regional Development Fund Programme 2007 to 2013Social Fund Convergence Programme for Cornwall and the Isles of Scill

Water Vapour Effects in Mass Measurement

Water vapour inside the mass comparator enclosure is a critical parameter. In fact, fluctuations of this parameter during mass weighing can lead to errors in the determination of an unknown mass. To control that, a proposal method is given and tested. Preliminary results of our observation of water vapour sorption and desorption processes from walls and mass standard are reported

What sow the seeds of hardship for the poorest of the poor? Towards increasing the performance of informal sector in war affected regions of Sri Lanka

Less performance of informal sector among the poorest of the poor in the war affected regions in Sri Lanka has been caused by many reasons. Findings of an exploratory study and the factor analysis revealed four important factors namely training and skills, education, social and economic. As the extension of the exploratory study, to test this prediction empirically with a larger sample size, the present study applied a survey method using a questionnaire especially designed based on the initial exploratory study which was conducted inductively. A sample of 300 women headed households engaged in the informal sector participated in this study. The results indicates these four factors significantly predict the performance of informal sector. More specifically, while, economic factors contribute more to the performance of the informal sector, training contributes less. The study also discussed the implication of findings and area for future research. Based on the findings and conclusions, few recommendations are also made to enhance the performance of women headed households in the informal sector