234 research outputs found
Can the Solar Wind be Driven by Magnetic Reconnection in the Sun's Magnetic Carpet?
The physical processes that heat the solar corona and accelerate the solar
wind remain unknown after many years of study. Some have suggested that the
wind is driven by waves and turbulence in open magnetic flux tubes, and others
have suggested that plasma is injected into the open tubes by magnetic
reconnection with closed loops. In order to test the latter idea, we developed
Monte Carlo simulations of the photospheric "magnetic carpet" and extrapolated
the time-varying coronal field. These models were constructed for a range of
different magnetic flux imbalance ratios. Completely balanced models represent
quiet regions on the Sun and source regions of slow solar wind streams. Highly
imbalanced models represent coronal holes and source regions of fast wind
streams. The models agree with observed emergence rates, surface flux
densities, and number distributions of magnetic elements. Despite having no
imposed supergranular motions, a realistic network of magnetic "funnels"
appeared spontaneously. We computed the rate at which closed field lines open
up (i.e., recycling times for open flux), and we estimated the energy flux
released in reconnection events involving the opening up of closed flux tubes.
For quiet regions and mixed-polarity coronal holes, these energy fluxes were
found to be much lower than required to accelerate the solar wind. For the most
imbalanced coronal holes, the energy fluxes may be large enough to power the
solar wind, but the recycling times are far longer than the time it takes the
solar wind to accelerate into the low corona. Thus, it is unlikely that either
the slow or fast solar wind is driven by reconnection and loop-opening
processes in the magnetic carpet.Comment: 25 pages (emulateapj style), 13 figures, ApJ, in pres
Myeloid malignancies in the real-world : Occurrence, progression and survival in the UK’s population-based Haematological Malignancy Research Network 2004–15
Background: Population-based information on cancer incidence, prevalence and outcome are required to inform clinical practice and research; but contemporary data are lacking for many myeloid malignancy subtypes. Methods: Set within a socio-demographically representative UK population of ~4 million, myeloid malignancy data (N = 5231 diagnoses) are from an established patient cohort. Information on incidence, survival (relative & overall), transformation/progression, and prevalence is presented for >20 subtypes. Results: The median diagnostic age was 72.4 years (InterQuartile Range 61.6-80.2), but there was considerable subtype heterogeneity, particularly among the acute myeloid leukaemias (AML) where medians ranged from 20.3 (IQR 13.9-43.8) for AML 11q23 through to 73.7 (IQR 57.3-79.1) for AML with no recurrent genetic changes. Five-year Relative Survival (RS) estimates varied hugely; from 85% for indolent/treatable conditions like chronic myeloid leukaemia (89.8%, 95% CI 84.0-93.6). With a couple of notable exceptions, males experienced higher rates and worse survival than females: the age-standardized incidence rates of several conditions was 2-4 higher in males than females, and the 5-year RS for all subtypes combined was 48.8% (95% CI 46.5-51.2) and 60.4% (95% CI 57.7-62.9) for males and females respectively. During follow-up (potential minimum 2 years and maximum 11 years) myelodysplastic syndrome (MDS) progression to AML ranged from 25% for refractory anaemia with excess blasts through to 5% for refractory anaemia with ring sideroblasts: the median interval between MDS and AML diagnosis was 9.0 months (IQR 4.8-17.4 months). Conclusions: The marked incidence and outcome variations seen by subtype, sex and age, confirm the requirement for "real-world" longitudinal data to inform aetiological hypotheses, healthcare planning, and future monitoring of therapeutic change. Several challenges for routine cancer registration were identified, including the need to link more effectively to diagnostic and clinical data sources, and to review policies on the recording of progressions and transformations
A Study of Cosmic Ray Composition in the Knee Region using Multiple Muon Events in the Soudan 2 Detector
Deep underground muon events recorded by the Soudan 2 detector, located at a
depth of 2100 meters of water equivalent, have been used to infer the nuclear
composition of cosmic rays in the "knee" region of the cosmic ray energy
spectrum. The observed muon multiplicity distribution favors a composition
model with a substantial proton content in the energy region 800,000 -
13,000,000 GeV/nucleus.Comment: 38 pages including 11 figures, Latex, submitted to Physical Review
Comparing nuclear power trajectories in Germany and the UK: from ‘regimes' to ‘democracies’ in sociotechnical transitions and Discontinuities
This paper focuses on arguably the single most striking contrast in contemporary major energy politics in Europe (and even the developed world as a whole): the starkly differing civil nuclear policies of Germany and the UK. Germany is seeking entirely to phase out nuclear power by 2022. Yet the UK advocates a ‘nuclear renaissance’, promoting the most ambitious new nuclear construction programme in Western Europe.Here,this paper poses a simple yet quite fundamental question: what are the particular divergent conditions most strongly implicated in the contrasting developments in these two countries. With nuclear playing such an iconic role in historical discussions over technological continuity and transformation, answering this may assist in wider understandings of sociotechnical incumbency and discontinuity in the burgeoning field of‘sustainability transitions’. To this end, an ‘abductive’ approach is taken: deploying nine potentially relevant criteria for understanding the different directions pursued in Germany and the UK. Together constituted by 30 parameters spanning literatures related to socio-technical regimes in general as well as nuclear technology in particular, the criteria are divided into those that are ‘internal’ and ‘external’ to the ‘focal regime configuration’ of nuclear power and associated ‘challenger technologies’ like renewables.
It is ‘internal’ criteria that are emphasised in conventional sociotechnical regime theory, with ‘external’ criteria relatively less well explored. Asking under each criterion whether attempted discontinuation of nuclear power would be more likely in Germany or the UK, a clear picture emerges. ‘Internal’ criteria suggest attempted nuclear discontinuation should be more likely in the UK than in Germany– the reverse of what is occurring.
‘External’ criteria are more aligned with observed dynamics –especially those relating to military nuclear commitments and broader ‘qualities of democracy’. Despite many differences of framing concerning exactly what constitutes ‘democracy’, a rich political science literature on this point is unanimous in characterising Germany more positively than the UK. Although based only on a single case,a potentially important question is nonetheless raised as to whether sociotechnical regime theory might usefully give greater attention to the general importance of various aspects of democracy in constituting conditions for significant technological discontinuities and transformations. If so, the policy implications are significant. A number of important areas are identified for future research, including the roles of diverse understandings and specific aspects of democracy and the particular relevance of military nuclear commitments– whose under-discussion in civil nuclear policy literatures raises its own questions of democratic accountability
Modeling the Subsurface Structure of Sunspots
While sunspots are easily observed at the solar surface, determining their
subsurface structure is not trivial. There are two main hypotheses for the
subsurface structure of sunspots: the monolithic model and the cluster model.
Local helioseismology is the only means by which we can investigate
subphotospheric structure. However, as current linear inversion techniques do
not yet allow helioseismology to probe the internal structure with sufficient
confidence to distinguish between the monolith and cluster models, the
development of physically realistic sunspot models are a priority for
helioseismologists. This is because they are not only important indicators of
the variety of physical effects that may influence helioseismic inferences in
active regions, but they also enable detailed assessments of the validity of
helioseismic interpretations through numerical forward modeling. In this paper,
we provide a critical review of the existing sunspot models and an overview of
numerical methods employed to model wave propagation through model sunspots. We
then carry out an helioseismic analysis of the sunspot in Active Region 9787
and address the serious inconsistencies uncovered by
\citeauthor{gizonetal2009}~(\citeyear{gizonetal2009,gizonetal2009a}). We find
that this sunspot is most probably associated with a shallow, positive
wave-speed perturbation (unlike the traditional two-layer model) and that
travel-time measurements are consistent with a horizontal outflow in the
surrounding moat.Comment: 73 pages, 19 figures, accepted by Solar Physic
The state of the Martian climate
60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes
Four simple recommendations to encourage best practices in research software [version 1; referees: awaiting peer review]
Scientific research relies on computer software, yet software is not always developed following practices that ensure its quality and sustainability. This manuscript does not aim to propose new software development best practices, but rather to provide simple recommendations that encourage the adoption of existing best practices. Software development best practices promote better quality software, and better quality software improves the reproducibility and reusability of research. These recommendations are designed around Open Source values, and provide practical suggestions that contribute to making research software and its source code more discoverable, reusable and transparent. This manuscript is aimed at developers, but also at organisations, projects, journals and funders that can increase the quality and sustainability of research software by encouraging the adoption of these recommendations.
Keyword
Community syndicalism for the United States: preliminary observations on law and globalization in democratic production
two structural labor crises for developed economies: 1) The channeling of substantial investment into non-productive, paper commodities, reducing growth of production for use and therefore reducing available aggregate job creation; and 2) The continued exportation of industrial jobs to other lower cost jurisdictions, and outsourcing, automation, just-in-time production, and speed-ups associated with global supply chains. As a result, local communities and regional populations have destabilized and even collapsed with attendant social problems. One possible response is Community Syndicalism – local community finance and operating credit for industrial production combined with democratic worker ownership and control of production. The result would increase investment directly for production, retain jobs in existing population centers, promote job skilling, and retain tax bases for local services and income supporting local businesses, at the same time increasing support for authentic political democracy by rendering the exploitive ideology of the Public/Private distinction superfluous. Slowing job exportation may reduce the global race to the bottom of labor standards and differential wage rates reducing the return to producers of value and increasing the skew of income distribution undermining social wages and welfare worldwide. Community Syndicalism can serve as moral goal in an alternative production model focusing incentives on long term stability of jobs and community economic base
Treatment cost and life expectancy of diffuse large B-cell lymphoma (DLBCL) : a discrete event simulation model on a UK population-based observational cohort
Background Diffuse large B-cell lymphoma (DLBCL) is the commonest non-Hodgkin lymphoma. Previous studies examining the cost of treating DLBCL have generally focused on specific first-line therapy alone; meaning that their findings can neither be extrapolated to the general patient population nor to other points along the treatment pathway. Based on empirical data from a representative population-based patient cohort, the objective of this study was to develop a simulation model that could predict costs and life expectancy of treating DLBCL. Methods All patients newly diagnosed with DLBCL in the UK’s population-based Haematological Malignancy Research Network (www.hmrn.org) in 2007 were followed until 2013 (n=271). Mapped treatment pathways, alongside cost information derived from the National Tariff 2013/14, were incorporated into a patient level simulation model in order to reflect the heterogeneities of patient characteristics and treatment options. The NHS and social services perspective was adopted, and all outcomes were discounted at 3.5% per annum. Results Overall, the expected total medical costs were £22,122 for those treated with curative intent, and £2,930 for those managed palliatively. For curative chemotherapy, the predicted medical costs were £14,966, £23,449 and £7,376 for first, second, and third line treatments, respectively. The estimated annual cost for treating DLBCL across the UK was around £88-92 million. Conclusions This is the first cost modelling study using empirical data to provide ‘real world’ evidence throughout the DLBCL treatment pathway. Future application of the model could include evaluation of new technologies/treatments to support healthcare decision makers, especially in the era of personalised medicine
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