8,228 research outputs found
The integrated dynamic land use and transport model MARS
Cities worldwide face problems like congestion or outward migration of businesses. The involved transport and land use interactions require innovative tools. The dynamic Land Use and Transport Interaction model MARS (Metropolitan Activity Relocation Simulator) is part of a structured decision making process. Cities are seen as self organizing systems. MARS uses Causal Loop Diagrams from Systems Dynamics to explain cause and effect relations. MARS has been benchmarked against other published models. A user friendly interface has been developed to support decision makers. Its usefulness was tested through workshops in Asia. This paper describes the basis, capabilities and uses of MARS
The complex relationship between household income of family caregivers, access to palliative care services and place of death : A national household population survey
BACKGROUND: Previous work shows that more affluent patients with cancer are more likely to die at home, whereas those dying from non-cancer conditions are more likely to die in hospital. Family caregivers are an important factor in determining place of death. AIM: To investigate associations between family caregivers' household income, patients' access to specialist palliative care and place of patients' death, by level of personal end-of-life care. DESIGN: A cross-sectional community household population survey. SETTING AND PARTICIPANTS: Respondents to the Household Survey for England. RESULTS: One-third of 1265 bereaved respondents had provided personal end-of-life care (caregivers) (30%). Just over half (55%) of decedents accessed palliative care services and 15% died in a hospice. Place of death and access to palliative care were strongly related ( p < 0.001). Palliative care services reduced the proportion of deaths in hospital ( p < 0.001), and decedents accessing palliative care were more likely to die at home than those who did not ( p < 0.001). Respondents' income was not associated with palliative care access ( p = 0.233). Overall, respondents' income and home death were not related ( p = 0.106), but decedents with caregivers in the highest income group were least likely to die at home ( p = 0.069). CONCLUSION: For people who had someone close to them die, decedents' access to palliative care services was associated with fewer deaths in hospital and more home deaths. Respondents' income was unrelated to care recipients' place of death when adjusted for palliative care access. When only caregivers were considered, decedents with caregivers from higher income quartiles were the least likely to die at home. Family caregivers from higher income brackets are likely to be powerful patient advocates. Caregiver information needs must be addressed especially with regard to stage of disease, aim of care and appropriate interventions at the end of life
Influence of LAR and VAR on Para-Aminopyridine Antimalarials Targetting Haematin in Chloroquine-Resistance
Antimalarial chloroquine (CQ) prevents haematin detoxication when CQ-base concentrates in the acidic digestive vacuole through protonation of its p-aminopyridine (pAP) basic aro- matic nitrogen and sidechain diethyl-N. CQ export through the variant vacuolar membrane export channel, PFCRT, causes CQ-resistance in Plasmodium falciparum but 3-methyl CQ (sontochin SC), des-ethyl amodiaquine (DAQ) and bis 4-aminoquinoline piperaquine (PQ) are still active. This is determined by changes in drug accumulation ratios in parasite lipid (LAR) and in vacuolar water (VAR). Higher LAR may facilitate drug binding to and blocking PFCRT and also aid haematin in lipid to bind drug. LAR for CQ is only 8.3; VAR is 143,482. More hydrophobic SC has LAR 143; VAR remains 68,523. Similarly DAQ with a phenol sub- stituent has LAR of 40.8, with VAR 89,366. In PQ, basicity of each pAP is reduced by distal piperazine N, allowing very high LAR of 973,492, retaining VAR of 104,378. In another bis quinoline, dichlorquinazine (DCQ), also active but clinically unsatisfactory, each pAP retains basicity, being insulated by a 2-carbon chain from a proximal nitrogen of the single linking piperazine. While LAR of 15,488 is still high, the lowest estimate of VAR approaches 4.9 million. DCQ may be expected to be very highly lysosomotropic and therefore potentially hepatotoxic. In 11 pAP antimalarials a quadratic relationship between logLAR and logRe- sistance Index (RI) was confirmed, while log (LAR/VAR) vs logRI for 12 was linear. Both might be used to predict the utility of structural modifications
The elastic constants of MgSiO3 perovskite at pressures and temperatures of the Earth's mantle
The temperature anomalies in the Earth's mantle associated with thermal
convection1 can be inferred from seismic tomography, provided that the elastic
properties of mantle minerals are known as a function of temperature at mantle
pressures. At present, however, such information is difficult to obtain
directly through laboratory experiments. We have therefore taken advantage of
recent advances in computer technology, and have performed finite-temperature
ab initio molecular dynamics simulations of the elastic properties of MgSiO3
perovskite, the major mineral of the lower mantle, at relevant thermodynamic
conditions. When combined with the results from tomographic images of the
mantle, our results indicate that the lower mantle is either significantly
anelastic or compositionally heterogeneous on large scales. We found the
temperature contrast between the coldest and hottest regions of the mantle, at
a given depth, to be about 800K at 1000 km, 1500K at 2000 km, and possibly over
2000K at the core-mantle boundary.Comment: Published in: Nature 411, 934-937 (2001
Homological Localisation of Model Categories
One of the most useful methods for studying the stable homotopy category is localising at some spectrum E. For an arbitrary stable model category we introduce a candidate
for the E–localisation of this model category. We study the properties of this new construction and relate it to some well–known categories
Modelling and simulating change in reforesting mountain landscapes using a social-ecological framework
Natural reforestation of European mountain landscapes raises major environmental and societal issues. With local stakeholders in the Pyrenees National Park area (France), we studied agricultural landscape colonisation by ash (Fraxinus excelsior) to enlighten its impacts on biodiversity and other landscape functions of importance for the valley socio-economics. The study comprised an integrated assessment of land-use and land-cover change (LUCC) since the 1950s, and a scenario analysis of alternative future policy. We combined knowledge and methods from landscape ecology, land change and agricultural sciences, and a set of coordinated field studies to capture interactions and feedback in the local landscape/land-use system. Our results elicited the hierarchically-nested relationships between social and ecological processes. Agricultural change played a preeminent role in the spatial and temporal patterns of LUCC. Landscape colonisation by ash at the parcel level of organisation was merely controlled by grassland management, and in fact depended on the farmer's land management at the whole-farm level. LUCC patterns at the landscape level depended to a great extent on interactions between farm household behaviours and the spatial arrangement of landholdings within the landscape mosaic. Our results stressed the need to represent the local SES function at a fine scale to adequately capture scenarios of change in landscape functions. These findings orientated our modelling choices in the building an agent-based model for LUCC simulation (SMASH - Spatialized Multi-Agent System of landscape colonization by ASH). We discuss our method and results with reference to topical issues in interdisciplinary research into the sustainability of multifunctional landscapes
Methodological bias in cluster randomised trials
Background: Cluster randomised trials can be susceptible to a range of methodological problems. These problems are not commonly recognised by many researchers. In this paper we discuss the issues that can lead to bias in cluster trials. Methods: We used a sample of cluster randomised trials from a recent review and from a systematic review of hip protectors. We compared the mean age of participants between intervention groups in a sample of 'good' cluster trials with a sample of potentially biased trials. We also compared the effect sizes, in a funnel plot, between hip protector trials that used individual randomisation compared with those that used cluster randomisation. Results: There is a tendency for cluster trials, with evidence methodological biases, to also show an age imbalance between treatment groups. In a funnel plot we show that all cluster trials show a large positive effect of hip protectors whilst individually randomised trials show a range of positive and negative effects, suggesting that cluster trials may be producing a biased estimate of effect. Conclusion: Methodological biases in the design and execution of cluster randomised trials is frequent. Some of these biases associated with the use of cluster designs can be avoided through careful attention to the design of cluster trials. Firstly, if possible, individual allocation should be used. Secondly, if cluster allocation is required, then ideally participants should be identified before random allocation of the clusters. Third, if prior identification is not possible, then an independent recruiter should be used to recruit participants
Collaborative research and development (R&D) for climate technology transfer and uptake in developing countries: Towards a needs driven approach
While international cooperation to facilitate the transfer and uptake of climate technologies in developing countries is an ongoing part of climate policy conversations, international collaborative R&D has received comparatively little attention. Collaborative R&D, however, could be a potentially important contributor to facilitating the transfer and uptake of climate technologies in developing countries. But the complexities of international collaborative R&D options and their distributional consequences have been given little attention to date. This paper develops a systematic approach to informing future empirical research and policy analysis on this topic. Building on insights from relevant literature and analysis of empirical data based on a sample of existing international climate technology R&D initiatives, three contributions are made. First, the paper analyses the coverage of existing collaborative R&D efforts in relation to climate technologies, highlighting some important concerns, such as a lack of coverage of lower-income countries or adaptation technologies. Second, it provides a starting point for further systematic research and policy thinking via the development of a taxonomic approach for analysing collaborative designs. Finally, it matches characteristics of R&D collaborations against developing countries’ climate technology needs to provide policymakers with guidance on how to Configure R&D collaborations to meet these needs
The local symmetries of M-theory and their formulation in generalised geometry
In the doubled field theory approach to string theory, the T-duality group is
promoted to a manifest symmetry at the expense of replacing ordinary Riemannian
geometry with generalised geometry on a doubled space. The local symmetries are
then given by a generalised Lie derivative and its associated algebra. This
paper constructs an analogous structure for M-theory. A crucial by-product of
this is the derivation of the physical section condition for M-theory
formulated in an extended space.Comment: 20 pages, v2: Author Name corrected, v3: typos correcte
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