817 research outputs found
Shuttle orbiter Ku-band radar/communications system design evaluation: High gain antenna/widebeam horn
The physical characteristics of the high gain antenna reflector and feed elements are described. Deficiencies in the sum feed are discussed, and lack of atmospheric venting is posed as a potential problem area. The measured RF performance of the high gain antenna is examined and the high sidelobe levels measured are related to the physical characteristics of the antenna. An examination of the attributes of the feed which might be influenced by temperature extremes shows that the antenna should be insensitive to temperature variations. Because the feed support bipod structure is considered a significant contributor to the high sidelobe levels measured in the azimuth plane, pod relocation, material changes, and shaping are suggested as improvements. Alternate feed designs are presented to further improve system performance. The widebeam horn and potential temperature effects due to the polarizer are discussed as well as in the effects of linear polarization on TDRS acquisition, and the effects of circular polarization on radar sidelobe avoidance. The radar detection probability is analyzed as a function of scan overlap and target range
Shuttle orbiter Ku-band radar/communications system design evaluation
Tasks performed in an examination and critique of a Ku-band radar communications system for the shuttle orbiter are reported. Topics cover: (1) Ku-band high gain antenna/widebeam horn design evaluation; (2) evaluation of the Ku-band SPA and EA-1 LRU software; (3) system test evaluation; (4) critical design review and development test evaluation; (5) Ku-band bent pipe channel performance evaluation; (6) Ku-band LRU interchangeability analysis; and (7) deliverable test equipment evaluation. Where discrepancies were found, modifications and improvements to the Ku-band system and the associated test procedures are suggested
Representation of a complex Green function on a real basis: I. General Theory
When the Hamiltonian of a system is represented by a finite matrix,
constructed from a discrete basis, the matrix representation of the resolvent
covers only one branch. We show how all branches can be specified by the phase
of a complex unit of time. This permits the Hamiltonian matrix to be
constructed on a real basis; the only duty of the basis is to span the
dynamical region of space, without regard for the particular asymptotic
boundary conditions that pertain to the problem of interest.Comment: about 40 pages with 5 eps-figure
Biological Records Centre Annual Report 2005-2006
The period covered by this report is the first year of a new six-year partnership between CEH and JNCC. For this period, there is increased emphasis on targeted survey, on analysis and interpretation and on communications and outreach. These activities were always part of BRC’s work, but they have been given greater prominence as a result of rapid developments in information technology. Data are increasingly reaching BRC in electronic form, so that the effort of data entry and collation is reduced.
The data, collected by many volunteers and then collated and analysed at BRC, document the changing status and distribution of plants and animals in Britain. Distribution maps are published in atlases and are available via the internet through the NBN Gateway. The effects of change or loss of habitats, the influence of climate change and the consequences of changing water quality are all examples of the environmental factors that affect our biodiversity and which BRC aims to document and understand. The results are vital for developing environmental policies, to support conservation, and for fundamental ecological research.
BRC is funded jointly by JNCC and NERC through a partnership based on a Memorandum of Agreement (MoA). The partnership started in 1973 when the Nature Conservancy was divided to form the successor bodies Nature Conservancy Council (NCC) and Institute of Terrestrial Ecology (ITE). NCC was in turn divided further to form JNCC and three Country Agencies, while ITE was merged with other NERC units to form CEH. Through all these changes, the partnership has been maintained. A six-year memorandum of agreement ended on 31 January 2005 (Hill et al. 2005). The present report covers the first full year, 2005-6, of the new agreement for 2005-2010.
Rapid progress in information technology continues to be highly beneficial for BRC, whose data are increasingly used by the UK country conservation agencies, environmental consultants, NGOs, research workers, policy makers and volunteers. It is gratifying to know that, through our ability to display data on the National Biodiversity Network (NBN) Gateway, some of our data suppliers now have immediate access to their own data in a convenient form.
The year 2005-6 has been one of steady progress, with new datasets added to BRC, substantial additions to existing data, and improved communication with the NBN Gateway. The most high profile activity of the year has been the Harlequin Ladybird Survey, which has enabled us to observe the early stages of colonization by a mobile insect in greater detail than has been possible in any previous case
The pathway to net zero heating in the UK
This is the final version. Available from UKERC via the DOI in this record. The heating of homes is a major contributor to the UK’s greenhouse gas
emissions accounting for 13% of total emissions.  This is comparable to the
carbon emissions of all petrol and diesel cars in the UK. 2 Meeting the UK
government’s net zero emissions goal for 2050 will only be possible by complete
decarbonisation of the building stock (both existing and new). While emissions
from heating have fallen by 11% since 1990, much of which was driven by
efficiency programmes and regulation in the period 2002-2012 3, continuing
decarbonisation at this pace would get us to zero emissions from buildings in
235 years and fall far short of meeting the 2050 target
Relativistic J-matrix method
The relativistic version of the J-matrix method for a scattering problem on
the potential vanishing faster than the Coulomb one is formulated. As in the
non-relativistic case it leads to a finite algebraic eigenvalue problem. The
derived expression for the tangent of phase shift is simply related to the
non-relativistic case formula and gives the latter as a limit case. It is due
to the fact that the used basis set satisfies the ``kinetic balance
condition''.Comment: 21 pages, RevTeX, accepted for publication in Phys. Rev.
Ultramicronized palmitoylethanolamide rescues learning and memory impairments in a triple transgenic mouse model of Alzheimer's disease by exerting anti-inflammatory and neuroprotective effects
In an aging society, Alzheimer’s disease (AD) exerts an increasingly serious health and economic burden. Current treatments provide inadequate symptomatic relief as several distinct pathological processes are thought to underlie the decline of cognitive and neural function seen in AD. This suggests that the efficacy of treatment requires a multitargeted approach. In this context, palmitoylethanolamide (PEA) provides a novel potential adjunct therapy that can be incorporated into a multitargeted treatment strategy. We used young (6-month-old) and adult (12-month-old) 3×Tg-AD mice that received ultramicronized PEA (um-PEA) for 3 months via a subcutaneous delivery system. Mice were tested with a range of cognitive and noncognitive tasks, scanned with magnetic resonance imaging/magnetic resonance spectroscopy (MRI/MRS), and neurochemical release was assessed by microdialysis. Potential neuropathological mechanisms were assessed postmortem by western blot, reverse transcription–polymerase chain reaction (RT-PCR), and immunofluorescence. Our data demonstrate that um-PEA improves learning and memory, and ameliorates both the depressive and anhedonia-like phenotype of 3×Tg-AD mice. Moreover, it reduces Aβ formation, the phosphorylation of tau proteins, and promotes neuronal survival in the CA1 subregion of the hippocampus. Finally, um-PEA normalizes astrocytic function, rebalances glutamatergic transmission, and restrains neuroinflammation. The efficacy of um-PEA is particularly potent in younger mice, suggesting its potential as an early treatment. These data demonstrate that um-PEA is a novel and effective promising treatment for AD with the potential to be integrated into a multitargeted treatment strategy in combination with other drugs. Um-PEA is already registered for human use. This, in combination with our data, suggests the potential to rapidly proceed to clinical use
Climate Clever Beef : On-farm demonstration of adaptation and mitigation options for climate change in northern Australia
This project engaged with beef producers in five regions of northern Australia to identify management options that improve the performance and resilience of beef businesses. The work was done in the context of increasing the resilience of businesses to current climate variability as well as to projected changes in climate. The project also identified potential synergies and conflicts between improved business performance, climate adaptation practices and greenhouse gas emissions management.
Three regions (Qld Gulf, Fitzroy Basin and Victoria River District) evaluated climate adaptation and greenhouse gas mitigation options via a benchmarking and options analysis approach with three “focal” properties. Five indicators of performance were evaluated for each property – profitability, productivity, land condition, climate change risk and greenhouse gas emissions. These detailed business analyses were complemented by demonstration sites in each region. Two other regions (Qld Mitchell grasslands and NT Barkly Tablelands) used on-property demonstration sites to showcase promising climate adaptation practices identified in a previous project.
The focal property approach provided a systematic process for assessing current business performance as well as a ready means of estimating the impacts of management changes. For example, over a 15 year period, the Qld Gulf focal property improved its pasture condition dramatically by stocking around the long-term carrying capacity and undertaking wet season spelling. This, combined with herd management improvements, increased profitability and productivity, reduced greenhouse gas emissions by 15%, and improved greenhouse gas emission efficiency by >100%.
The demonstration sites in each region effectively promoted and documented the benefits of key grazing practices for improving resilience to both current climate variability and potential climate change. For example, on a 16,118km² property in the Barkly, a paddock demonstration has documented initial land condition recovery at old bores, and the reduced risk of overgrazing around new bores, through best practice stocking rate management and wet season spelling.
Qualitative analyses showed that many of the adaptation practices identified for improving resilience are consistent with existing best practice recommendations aimed at improving productivity and sustainability. Furthermore, these adaptation practices appear to have largely neutral implications for greenhouse gas emissions. In contrast, practices and options for reducing greenhouse gas emissions were more likely to create conflicts that leave enterprises more vulnerable to climate change. Examples of the negative consequences of mitigation measures include reduced pasture production associated with increased carbon sequestration in trees (i.e. woody vegetation thickening or regrowth retention) and increased operating costs associated with carbon pricing (if these are not offset with carbon credits).
The project demonstration sites and focal property benchmarking process provided a solid base for focussed extension work targeting the drivers of profit, land condition, greenhouse gas emissions intensity and climate adaptation strategies
Agent-based Social Psychology: from Neurocognitive Processes to Social Data
Moral Foundation Theory states that groups of different observers may rely on
partially dissimilar sets of moral foundations, thereby reaching different
moral valuations. The use of functional imaging techniques has revealed a
spectrum of cognitive styles with respect to the differential handling of novel
or corroborating information that is correlated to political affiliation. Here
we characterize the collective behavior of an agent-based model whose inter
individual interactions due to information exchange in the form of opinions are
in qualitative agreement with experimental neuroscience data. The main
conclusion derived connects the existence of diversity in the cognitive
strategies and statistics of the sets of moral foundations and suggests that
this connection arises from interactions between agents. Thus a simple
interacting agent model, whose interactions are in accord with empirical data
on conformity and learning processes, presents statistical signatures
consistent with moral judgment patterns of conservatives and liberals as
obtained by survey studies of social psychology.Comment: 11 pages, 4 figures, 2 C codes, to appear in Advances in Complex
System
Making a home, finding a job: investigating early housing and employment outcomes for young people leaving care
This paper presents findings from a new study of outcomes for young people leaving care funded by the Department for Education and Skills. It reports findings for a sample of 106 young people in relation to progress made in housing and employment some 12-15 months after leaving care. The generally poor employment outcomes of care leavers are acknowledged, but ingredients that make for success are also highlighted, including the value of settled care and post-care careers, sound career planning and, significantly, the value of delaying young people's transitions from care. Early career paths also interconnect with how young people fare in housing, in developing life skills and with other problems in their lives after leaving care. Housing outcomes were more encouraging and predominantly shaped by events after leaving care, and faring well in housing was the factor most closely associated with positive mental well-being in young people. Some groups that are at risk of faring badly are identified, including young people with mental-health problems, young people with persistent offending or substance misuse problems and, in some respects, young disabled people. The implications of these findings for leaving care services are considered
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