21,234 research outputs found
Formation and morphology of anomalous solar circular polarization
The morphology of spectral line polarization is the most valuable observable
to investigate the magnetic and dynamic solar atmosphere. However, in order to
develop solar diagnosis, it is fundamental to understand the different kinds of
anomalous solar signals that have been routinely found in linear and circular
polarization (LP,CP). The goal of this paper has been to explain and
characterize the morphology of solar CP signals by understanding the combined
effect of magnetic fields, velocity gradients, and atomic orientation in
general NLTE regime. To that aim, an analytical two-layer model of the
polarized radiative transfer equation is developed and used to solve the NLTE
problem with atomic polarization in a semi-parametric way. The formation of
polarization is thus insightfully described with certain precision without
resorting in MHD models or sacrifying key physical ingredients. The potential
of the model for reproducing solar anomalous CP is shown with detailed
calculations. The essential physical behavior of dichroism and atomic
orientation is described, introducing the concepts of dichroic inversion,
neutral and reinforcing medium, critic intensity spectrum, and critic source
function. It is shown that the zero-crossings of the CP spectrum are useful to
classify its morphology and understand its formation. This led to identify and
explain the morphology of the seven most characteristics CP signals that a
single (depth-resolved) scattering layer can produce. Futhermore, it is found
that a minimal number of two magnetic layers along the LOS is required to fully
explain anomalous solar CP signals, and that the morphology and polarity of
Stokes V depends on magnetic, radiative and atomic polarities. Some
implications of these results are presented through a preliminar modeling of
anomalous CP signals in the Na I D and Fe I 1564.8 nm lines.Comment: 18 pages, 18 figures. Accepted for publication in A&A. Typos and
language correcte
'Join Us On Our Journey': developing a new model of care for children and young people with type 1 diabetes Final report for NHS Diabetes
The aims of this research were to develop a model of care that will deliver the aspirations of the policy document, âMaking Every Young Person with Diabetes Matterâ and improve the care provision for children and young people with Type 1 diabetes in England. Children and young people with Type 1 diabetes, their families and professionals, in nine acute trusts throughout the Yorkshire and the Humber region, participated in talking group discussions and individual interviews to find out about their experiences of diabetes care provision. Findings show that there are certain aspects of the care pathway that need to be addressed. In particular, diabetes care, resources, education, psychological support, school/college and transition were found to be the main areas of concern. Recommendations have been made indicating how current practice needs to change if the care of children and young people with Type 1 diabetes is to improve
Good Institutions are not enough: Ongoing Challenges of East German Development
A major theme in accounts of the transitional recession and delayed convergence in post-communist economies is the role of institutions. Yet via unification, East Germany had immediate access to credible, high quality institutions. This paper argues that success in a capitalist economy depends not only on high quality institutions but also on finding oneâs niche in the international division of labour. East Germanyâs experience highlights the long shadow cast by the period under communism over the economyâs ability to find its comparative advantage in tradeables on a scale adequate for self-sustaining growth.transition, institutions, East Germany, tradeables, convergence
German economic performance: disentangling the role of supply-side reforms, macroeconomic policy and coordinated economy institutions
Since unification, the debate about Germany's poor economic performance has focused on supply-side weaknesses, and the associated reform agenda sought to make low-skill labour markets more flexible. We question this diagnosis using three lines of argument. First, effective restructuring of the supply side in the core advanced industries was carried out by the private sector using institutions of the coordinated economy, including unions, works councils and blockholder owners. Second, the implementation of orthodox labour market and welfare state reforms created a flexible labour market at the lower end. Third, low growth and high unemployment are largely accounted for by the persistent weakness of domestic aggregate demand, rather than by the failure to reform the supply side. Strong growth in recent years reflects the successful restructuring of the core economy. To explain these developments, we identify the external pressures on companies in the context of increased global competition, the continuing value of the institutions of the coordinated market economy to the private sector and the constraints imposed on the use of stabilizing macroeconomic policy by these institutions. We also suggest how changes in political coalitions allowed orthodox labour market reforms to be implemented in a consensus political system
A Conversation with Alan Gelfand
Alan E. Gelfand was born April 17, 1945, in the Bronx, New York. He attended
public grade schools and did his undergraduate work at what was then called
City College of New York (CCNY, now CUNY), excelling at mathematics. He then
surprised and saddened his mother by going all the way across the country to
Stanford to graduate school, where he completed his dissertation in 1969 under
the direction of Professor Herbert Solomon, making him an academic grandson of
Herman Rubin and Harold Hotelling. Alan then accepted a faculty position at the
University of Connecticut (UConn) where he was promoted to tenured associate
professor in 1975 and to full professor in 1980. A few years later he became
interested in decision theory, then empirical Bayes, which eventually led to
the publication of Gelfand and Smith [J. Amer. Statist. Assoc. 85 (1990)
398-409], the paper that introduced the Gibbs sampler to most statisticians and
revolutionized Bayesian computing. In the mid-1990s, Alan's interests turned
strongly to spatial statistics, leading to fundamental contributions in
spatially-varying coefficient models, coregionalization, and spatial boundary
analysis (wombling). He spent 33 years on the faculty at UConn, retiring in
2002 to become the James B. Duke Professor of Statistics and Decision Sciences
at Duke University, serving as chair from 2007-2012. At Duke, he has continued
his work in spatial methodology while increasing his impact in the
environmental sciences. To date, he has published over 260 papers and 6 books;
he has also supervised 36 Ph.D. dissertations and 10 postdocs. This interview
was done just prior to a conference of his family, academic descendants, and
colleagues to celebrate his 70th birthday and his contributions to statistics
which took place on April 19-22, 2015 at Duke University.Comment: Published at http://dx.doi.org/10.1214/15-STS521 in the Statistical
Science (http://www.imstat.org/sts/) by the Institute of Mathematical
Statistics (http://www.imstat.org
Learning to Detect and Track Cells for Quantitative Analysis of Time-Lapse Microscopic Image Sequences
© 2015 IEEE.Studying the behaviour of cells using time-lapse microscopic imaging requires automated processing pipelines that enable quantitative analysis of a large number of cells. We propose a pipeline based on state-of-the-art methods for background motion compensation, cell detection, and tracking which are integrated into a novel semi-automated, learning based analysis tool. Motion compensation is performed by employing an efficient nonlinear registration method based on powerful discrete graph optimisation. Robust detection and tracking of cells is based on classifier learning which only requires a small number of manual annotations. Cell motion trajectories are generated using a recent global data association method and linear programming. Our approach is robust to the presence of significant motion and imaging artifacts. Promising results are presented on different sets of in-vivo fluorescent microscopic image sequences
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