4,600 research outputs found
Comparative analyses of space-to-space central power stations
The technological and economical impact of a large central power station in Earth orbit on the performance and cost of future spacecraft and their orbital transfer systems are examined. It is shown that beaming power to remote users cannot be cost effective if the central power station uses the same power generation system that is readily available for provision of onboard power and microwave transmission and reception of power through space for use in space is not cost competitive with onboard power or propulsion systems. Laser and receivers are required to make central power stations feasible. Remote power transmission for propulsion of orbital transfer vehicles promises major cost benefits. Direct nuclear pumped or solar pumped laser power station concepts are attractive with laser thermal and laser electric propulsion systems. These power stations are also competitive, on a mass and cost basis, with a photovoltaic power station
The orbital recovery problem. Part II - Application of analysis technique to selection of recovery sites for return from low circular orbits
Lateral range requirements used in selecting spacecraft landing recovery sites for return from low circular orbit
Determinants of a transcriptionally competent environment at the GM-CSF promoter
Granulocyte macrophage-colony stimulating factor
(GM-CSF) is produced by T cells, but not B cells,
in response to immune signals. GM-CSF gene
activation in response to T-cell stimulation requires
remodelling of chromatin associated with the
gene promoter, and these changes do not occur in
B cells. While the CpG methylation status of the
murine GM-CSF promoter shows no correlation with
the ability of the gene to respond to activation, we
find that the basal chromatin environment of the
gene promoter influences its ability to respond to
immune signals. In unstimulated T cells but not B
cells, the GM-CSF promoter is selectively marked
by enrichment of histone acetylation, and association
of the chromatin-remodelling protein BRG1.
BRG1 is removed from the promoter upon activation
concomitant with histone depletion and BRG1
is required for efficient chromatin remodelling and
transcription. Increasing histone acetylation at
the promoter in T cells is paralleled by increased
BRG1 recruitment, resulting in more rapid chromatin
remodelling, and an associated increase in GM-CSF
mRNA levels. Furthermore, increasing histone
acetylation in B cells removes the block in chromatin
remodelling and transcriptional activation
of the GM-CSF gene. These data are consistent
with a model in which histone hyperacetylation
and BRG1 enrichment at the GM-CSF promoter,
generate a chromatin environment competent
to respond to immune signals resulting in gene
activation
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'Open Marxism' against and beyond the 'Great Enclosure'? Reflections on How (Not) to Crack Capitalism
The main purpose of this article is to provide an in-depth discussion of John Holloway’s recent book, Crack Capitalism. To this end, the paper offers a detailed account of the key strengths and weaknesses of Holloway’s version of ‘open Marxism’. The analysis is divided into two parts. The first part focuses on six significant strengths of Crack Capitalism: (1) its insistence upon the importance of autonomous forms of agenda-setting for both individual and collective emancipation; (2) its emphasis on the ordinary constitution of social struggles; (3) its fine-grained interpretation of the socio-ontological conditions underlying human agency; (4) its processual conception of radical social transformation; (5) its recognition of the elastic, adaptable, and integrative power of capitalism; and (6) its proposal for an alternative critical theory, commonly known as ‘open Marxism’ or ‘autonomous Marxism’. The second part of the study examines the principal weaknesses of Crack Capitalism: (1) the counterproductive implications of the preponderance of negativity, owing to a one-sided concern with critique, cracks, and crises; (2) conceptual vagueness; (3) an overuse of poetic and metaphorical language; (4) the absence of a serious engagement with the question of normativity; (5) a lack of substantive evidence; (6) a residual economic reductionism; (7) a simplistic notion of gender; (8) the continuing presence of various problematic ‘isms’; (9) the misleading distinction between ‘doing’ and ‘labour’; (10) a reductive understanding of capitalism; (11) an unrealistic view of society; and (12) socio-ontological idealis
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Climate models underestimate dynamic cloud feedbacks in the tropics
We acknowledge funding from the UK Natural Environment Research Council for the CIRCULATES project (Grant NE/T006315/1). Mark Webb was supported by the Met Office Hadley Centre Climate Programme funded by BEIS and Defra. We also acknowledge the World Climate Research Programme, which, through its Working Group on Coupled Modelling, coordinated and promoted CMIP6.Cloud feedbacks are the leading cause of uncertainty in climate sensitivity. The complex coupling between clouds and the large-scale circulation in the tropics contributes to this uncertainty. To address this problem, the coupling between clouds and circulation in the latest generation of climate models is compared to observations. Significant biases are identified in the models. The implications of these biases are assessed by combining observations of the present day with future changes predicted by models to calculate observationally constrained feedbacks. For the dynamic cloud feedback (i.e., due to changes in circulation), the observationally constrained values are consistently larger than the model-only values. This is due to models failing to capture a nonlinear minimum in cloud brightness for weakly descending regimes. Consequently, while the models consistently predict that these regimes increase in frequency in association with a weakening tropical circulation, they underestimate the positive cloud feedback associated with this increase.Publisher PDFPeer reviewe
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Evaluation of Corba for use in distributed control systems
The Common Object Request Broker Architecture (CORBA)-based Simulator was a Laboratory Directed Research and Development (LDRD) project that applied simulation techniques to explore critical questions about advanced distributed control system architectures. A three-prong approach comprised of a study of object-oriented distribution tools, computer network modeling, and simulation of key control system scenarios was used in the LDRD project. This input report describes the first of the three approaches Ñ the study of object-oriented distribution tools together with measurements, and predictions of use within the National Ignition Facility (NIF) and some aspects of CORBA which remain to be resolved. For the ICCS, the completeness of suitable functionality, the speed of performance and utilization of machine and network resources, and the developing nature of the commercial CORBA products themselves, presented a certain risk. This LDRD thus evaluated CORBA in general, and a particular implementation, to determine its features, performance, and scaling properties, and to optimize its use within the ICCS. Both UNIX and real-time operating systems were studied
National report on patient outcomes in palliative care in Australia: January - June 2014: report 17
The Palliative Care Outcomes Collaboration (PCOC) assists services to improve the quality of the palliative care they provide through the analysis and benchmarking of patient outcomes. In this, the seventeenth PCOC report, data submitted for the January to June 2014 period are summarised and patient outcomes benchmarked to enable participating services to assess their performance and identify areas in which they may improve
A Preliminary Study to Understand How Mainstream Accessibility and Digital Assistive Technologies Reaches People in Lower- and Middle-Income Countries
Accessibility to mainstream digital devices and the use of Digital Assistive Technologies (Digital AT) facilitates participation and improves function and independece of people with disabilities in these regions. However, mainstream access is not fully realised in LMICs and there are multiple barriers in the way for the uptake and use of Digital AT. Through a thematic analysis of interviews with eight expert professionals in the domain of provisioning Digital AT and its related services in LMICs, we discuss five steps or barriers for the uptake and use of Digital AT and have identified three practical strategies that have shown evidence to overcome these barriers. Developers of Digital AT will find these insights useful and the same will provide an understanding of the market to business strategists to deliver pathways to better accessibility services and new Digital AT
Decentralisation and performance: Autonomy and incentives in Local Health Economies
This project will examine the inter-relationship between governance mechanisms, autonomy and incentives in local health economies (LHEs). This interaction shapes decentralisation policies in the NHS and is thought to shape LHE performance. Recently, English health policy has been implementing new forms of decentralisation (eg. earned autonomy, Foundation Trusts) by altering the mix of governance mechanisms (command, collaboration and competition) and making explicit use of autonomy and incentives, thereby aiming to improve NHS performance. Local contextual factors might also shape performance outcomes. The project involves a synergy between the multi-disciplinary teams involved in 2 previous NCC-SDO funded studies. The aim is to investigate the inter-relationship between decentralisation and performance in LHEs. The project has 5 objectives: a. To examine the impact of decentralisation upon performance through analysis of selected 'tracers (as examples of current priorities) in 3 case-studies; b. To describe the local interaction of governance mechanisms; c. To evaluate the degree of autonomy available to local health-care organisations; d. To assess the (financial and non-financial) incentives associated with different policy initiatives; e. To provide lessons for policy-makers and managers at all levels in implementing decentralisation, managing the implications of autonomy and incentives, and addressing performance management through incentives. The study will use mixed methods. First, analysis of policy and performance data will generate the broad pattern of decentralisation and performance across England. Analysis of these data will aid selection of case-studies and 'tracers (examples within case-studies). Second, three case-studies will be selected which represent a maximum variety of pre-defined criteria. Longitudinal, comparative case-study methods include (a) 'mapping LHE performance and organisational characteristics (using local performance and activity data, and published reports); (b) a survey of senior staff in 3 LHEs (n=c.180) to provide their perceptions of current LHE issues and constraints (especially relating to tracer examples); (c) interviews with a sample of stakeholders (n=c.120) will identify the strengths and effects of organisational relationships across the LHE (such as the impact of service developments in the tracer examples); (d) observation of local planning meetings. Parts (a) and (b) will be conducted in year 1, parts (c) and (d) in years 2 and 3. Quantitative analysis will provide descriptive statistics of broad patterns and association. Qualitative analysis will provide thematic comparisons by LHE, organisational type and tracer example. Analysis will identify the pathways by which governance, autonomy and incentives can facilitate improved performance and also the conditions under which the optimal balance of these may be achieved in different contexts. The study will also consider conceptual frameworks (including 'decision space , resource dependency and principal-agent) to improve understanding of the inter-relationships within LHE and the intersection of national/vertical and local/horizontal pressures affecting performance. The study will engage decision-makers at all stages (via data collection, formative and summative feedback and as members of an Advisory Group). Formative feedback to LHEs (and NCC-SDO) will help validate emergent findings and sharpen subsequent fieldwork. Final dissemination will include such (oral and written) feedback, NCC-SDO report, presentations and publications to practitioner and research communities
Munc18c provides stimulus-selective regulation of GLUT4 but not fatty acid transporter trafficking in skeletal muscle
Insulin-, and contraction-induced GLUT4 and fatty acid (FA) transporter translocation may share common trafficking mechanisms. Our objective was to examine the effects of partial Munc18c ablation on muscle glucose and FA transport, FA oxidation, GLUT4 and FA transporter (FAT/CD36, FAB-Ppm, FATP1, FATP4) trafficking to the sarcolemma, and FAT/CD36 to mitochondria. In Munc18c(-/+) mice, insulin-stimulated glucose transport and GLUT4 sarcolemmal appearance were impaired, but were unaffected by contraction. Insulin- and contraction-stimulated FA transport, sarcolemmal FA transporter appearance, and contraction-mediated mitochondrial FAT/CD36 were increased normally in Munc18c(-/+) mice. Hence, Munc18c provides stimulus-specific regulation of GLUT4 trafficking, but not FA transporter trafficking
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