4,467 research outputs found
Percolation approach to phase transitions in high energy nuclear collisions
We study continuum percolation in nuclear collisions for the realistic case
in which the nuclear matter distribution is not uniform over the collision
volume, and show that the percolation threshold is increased compared to the
standard, uniform situation. In terms of quark-gluon plasma formation this
means that the phase transition threshold is pushed to higher energies.Comment: 7 pages, 4 figures (PS), LaTeX2e using fontenc, amsmath, epsfi
Playing with nonuniform grids
Numerical experiments with discretization methods on nonuniform grids are presented for the convection-diffusion equation. These show that the accuracy of the discrete solution is not very well predicted by the local truncation error. The diagonal entries in the discrete coefficient matrix give a better clue: the convective term should not reduce the diagonal. Also, iterative solution of the discrete set of equations is discussed. The same criterion appears to be favourable.
Theory of continuum percolation II. Mean field theory
I use a previously introduced mapping between the continuum percolation model
and the Potts fluid to derive a mean field theory of continuum percolation
systems. This is done by introducing a new variational principle, the basis of
which has to be taken, for now, as heuristic. The critical exponents obtained
are , and , which are identical with the mean
field exponents of lattice percolation. The critical density in this
approximation is \rho_c = 1/\ve where \ve = \int d \x \, p(\x) \{ \exp [-
v(\x)/kT] - 1 \}. p(\x) is the binding probability of two particles
separated by \x and v(\x) is their interaction potential.Comment: 25 pages, Late
Anomalous anisotropic cross-correlations between WMAP CMB maps and SDSS galaxy distribution and implications on the dark flow scenario
We search for the dark flow induced diffuse kinetic Sunyaev Zel'dovich (kSZ)
effect through CMB-galaxy cross correlation. Such angular correlation is
anisotropic, with a unique angular dependence and hence can be
distinguished from other components. Here, is the angle between the
opposite dark flow direction and the direction of the sky where the correlation
is measured. We analyze the KIAS-VAGC galaxy catalog of SDSS-DR7 and the WMAP
seven-year temperature maps, applying an unbiased optimal weighting scheme to
eliminate any statistically isotropic components and to enhance the dark flow
detection signal. Non-zero weighted cross correlations are detected at 3.5
sigma for the redshift bin z<0.1 and at 3 sigma for the bin 0.1<z<0.2, implying
the existence of statistically anisotropic components in CMB. However, further
analysis does not support the dark flow explanation. The observed directional
dependence deviates from the relation expected, and
hence can not be explained by the presence of a single dark flow, and if the
observed cross correlation is generated by the dark flow induced kSZ effect,
the velocity would be too high (> 6000 km/s). We report this work as the first
attempt to search for dark flow through weighted CMB-galaxy cross correlation
and to draw the attention on the sources of the detected anomalous CMB-galaxy
cross correlation.Comment: 8 pages, 8 figures, ApJ accepte
Mental, behavioral and neurodevelopmental disorders in the ICD-11 : An international perspective on key changes and controversies
The Author(s). 2020Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, andreproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link tothe Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.An update of the chapter on Mental, Behavioral and Neurodevelopmental Disorders in the International Classification of Diseases and Related Health Problems (ICD) is of great interest around the world. The recent approval of the 11th Revision of the ICD (ICD-11) by the World Health Organization (WHO) raises broad questions about the status of nosology of mental disorders as a whole as well as more focused questions regarding changes to the diagnostic guidelines for specific conditions and the implications of these changes for practice and research. This Forum brings together a broad range of experts to reflect on key changes and controversies in the ICD-11 classification of mental disorders. Taken together, there is consensus that the WHO's focus on global applicability and clinical utility in developing the diagnostic guidelines for this chapter will maximize the likelihood that it will be adopted by mental health professionals and administrators. This focus is also expected to enhance the application of the guidelines in non-specialist settings and their usefulness for scaling up evidence-based interventions. The new mental disorders classification in ICD-11 and its accompanying diagnostic guidelines therefore represent an important, albeit iterative, advance for the field.Peer reviewedFinal Published versio
Weather and Climate Information for Tourism
The tourism sector is one of the largest and fastest growing global industries and is a significant contributor to national and local economies around the world. The interface between climate and tourism is multifaceted and complex, as climate represents both a vital resource to be exploited and an important limiting factor that poses risks to be managed by the tourism industry and tourists alike. All tourism destinations and operators are climate-sensitive to a degree and climate is a key influence on travel planning and the travel experience. This chapter provides a synopsis of the capacities and needs for climate services in the tourism sector, including current and emerging applications of climate services by diverse tourism end-users, and a discussion of key knowledge gaps, research and capacity-building needs and partnerships that are required to accelerate the application of climate information to manage risks to climate variability and facilitate successful adaptation to climate change
Multiplex ligation-dependent probe amplification (MLPA) analysis is an effective tool for the detection of novel intragenic PLA2G6 mutations: Implications for molecular diagnosis
Phospholipase associated neurodegeneration (PLAN) comprises a heterogeneous group of autosomal recessive neurological disorders caused by mutations in the PLA2G6 gene. Direct gene sequencing detects 85% mutations in infantile neuroaxonal dystrophy. We report the novel use of multiplex ligation-dependent probe amplification (MLPA) analysis to detect novel PLA2G6 duplications and deletions. The identification of such copy number variants (CNVs) expands the PLAN mutation spectrum and may account for up to 12.5% of PLA2G6 mutations. MLPA should thus be employed to detect CNVs of PLA2G6 in patients who show clinical features of PLAN but in whom both disease-causing mutations cannot be identified on routine sequencin
Observations of quasi-periodic phenomena associated with a large blowout solar jet
A variety of periodic phenomena have been observed in conjunction with large
solar jets. We aim to find further evidence for {(quasi-)}periodic behaviour in
solar jets and determine what the periodic behaviour can tell us about the
excitation mechanism and formation process of the large solar jet. Using the
304 {\AA} (He-II), 171 {\AA} (Fe IX), 193 {\AA} (Fe XII/XXIV) and 131 {\AA} (Fe
VIII/XXI) filters on-board the Solar Dynamic Observatory (SDO) Atmospheric
Imaging Assembly (AIA), we investigate the intensity oscillations associated
with a solar jet. Evidence is provided for multiple magnetic reconnection
events occurring between a pre-twisted, closed field and open field lines.
Components of the jet are seen in multiple SDO/AIA filters covering a wide
range of temperatures, suggesting the jet can be classified as a blowout jet.
Two bright, elongated features are observed to be co-spatial with the large
jet, appearing at the jet's footpoints. Investigation of these features reveal
they are defined by multiple plasma ejections. The ejecta display
(quasi-)periodic behaviour on timescales of 50 s and have rise velocities of
40-150 km\,s along the open field lines. Due to the suggestion that the
large jet is reconnection-driven and the observed properties of the ejecta, we
further propose that these ejecta events are similar to type-II spicules. The
bright features also display (quasi)-periodic intensity perturbations on the
timescale of 300 s. Possible explanations for the existence of the
(quasi-)periodic perturbations in terms of jet dynamics and the response of the
transition region are discussed.Comment: Astronomy and Astrophysics - In Prin
An ADI extrapolated Crank-Nicolson orthogonal spline collocation method for nonlinear reaction-diffusion systems: a computational study
An alternating direction implicit (ADI) orthogonal spline collocation (OSC)
method is described for the approximate solution of a class of nonlinear
reaction-diffusion systems. Its efficacy is demonstrated on the solution of
well-known examples of such systems, specifically the Brusselator, Gray-Scott,
Gierer-Meinhardt and Schnakenberg models, and comparisons are made with other
numerical techniques considered in the literature. The new ADI method is based
on an extrapolated Crank-Nicolson OSC method and is algebraically linear. It is
efficient, requiring at each time level only operations where
is the number of unknowns. Moreover,it is shown to produce
approximations which are of optimal global accuracy in various norms, and to
possess superconvergence properties
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