1,222 research outputs found
On Hawking's Local Rigidity Theorems for Charged Black Holes
We show the existence of a Hawking vector field in a full neighborhood of a
local, regular, bifurcate, non-expanding horizon embedded in a smooth
Einstein-Maxwell space-time without assuming the underlying space-time is
analytic. It extends one result of Friedrich, R\'{a}cz and Wald, which was
limited to the interior of the black hole region. Moreover, we also show, in
the presence of an additional Killing vector field which tangent to the
horizon and not vanishing on the bifurcate sphere, then space-time must be
locally axially symmetric without the analyticity assumption. This axial
symmetry plays a fundamental role in the classification theory of stationary
black holes.Comment: 20 page
Serological prevalence of leptospiral antibodies in pigs in South Africa
A serological survey for leptospiral antibodies was carried out on 5 041 abattoir pigs from different regions in South Africa. Antibodies to at least one serovar were detected in 22,2% of the animals. The serovars showing the highest prevalence were: icterohaemorrhagiae (12,6%), hardjo (12,1 %) and bratislava (7,5%). The serum dilution level at which 90% of the sera reacted was 1/80 or 1/160.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201
A Hybrid Artificial Bee Colony Algorithm for Graph 3-Coloring
The Artificial Bee Colony (ABC) is the name of an optimization algorithm that
was inspired by the intelligent behavior of a honey bee swarm. It is widely
recognized as a quick, reliable, and efficient methods for solving optimization
problems. This paper proposes a hybrid ABC (HABC) algorithm for graph
3-coloring, which is a well-known discrete optimization problem. The results of
HABC are compared with results of the well-known graph coloring algorithms of
today, i.e. the Tabucol and Hybrid Evolutionary algorithm (HEA) and results of
the traditional evolutionary algorithm with SAW method (EA-SAW). Extensive
experimentations has shown that the HABC matched the competitive results of the
best graph coloring algorithms, and did better than the traditional heuristics
EA-SAW when solving equi-partite, flat, and random generated medium-sized
graphs
Queen’s Communities and Place: towards the alignment of higher education place-based strategy with local need
Serving as a key delivery mechanism for Queen’s University Belfast’s (UK) strategic commitment to social and civic responsibility and economic prosperity, Queen’s Communities and Place is a research initiative based on engagement and partnership between communities, policy makers and academics. Combining academic expertise and experiential knowledge from the community, Queen’s Communities and Place uses a ‘place-based’ approach to co-create new solutions to address persistent physical, economic and social challenges, as well as to strengthen the engagement between Queen’s University and its surrounding communities. Queen’s Communities and Place launched in November 2021 with our anchor partner in the Market community in inner south Belfast. We are also working collaboratively with projects and communities in the north, west and east of Belfast across a range of sectors and academic disciplines. We have sought to challenge existing frameworks, with evidence-led, data-driven approaches to build interventions and practices together to identify what might work better here for communities to thrive. Capturing three perspectives – academic, community and local government – this co-written reflective article details the experience of establishing a working partnership with our pilot community, and provides some examples of how our approach is working to address the challenges on the ground to date
Extremal limit of the regular charged black holes in nonlinear electrodynamics
The near horizon limit of the extreme nonlinear black hole is investigated.
It is shown that resulting geometry belongs to the AdS2xS2 class with different
modules of curvatures of subspaces and could be described in terms of the
Lambert functions. It is demonstrated that the considered class of Lagrangians
does not admit solutions of the Bertotti-Robinson type
Optimising approximate entropy for assessing cardiac dyssynchrony with radionuclide ventriculography
Left ventricular dyssynchrony can be assessed with phase parameters from radionuclide ventriculography (RNVG), including approximate entropy (ApEn). The input values used to calculate ApEn will affect the results significantly, so it is essential to optimise ApEn for the application. However to date, no optimisation for ApEn applied to images has been published. In this paper, generated data were used to simulate patient phase images, allowing the input parameters for ApEn to be tested and optimised in a controlled environment. Clinical images were then used to confirm that the selected parameters were appropriate. The results demonstrate the effect of input parameters for ApEn and the most appropriate use with RNVG phase images. This work demonstrates the importance of optimisation and standardisation when using ApEn as a measure of dyssynchrony
The Void Abundance with Non-Gaussian Primordial Perturbations
We use a Press-Schechter-like calculation to study how the abundance of voids
changes in models with non-Gaussian initial conditions. While a positive
skewness increases the cluster abundance, a negative skewness does the same for
the void abundance. We determine the dependence of the void abundance on the
non-Gaussianity parameter fnl for the local-model bispectrum-which approximates
the bispectrum in some multi-field inflation models-and for the equilateral
bispectrum, which approximates the bispectrum in e.g. string-inspired DBI
models of inflation. We show that the void abundance in large-scale-structure
surveys currently being considered should probe values as small as fnl < 10 and
fnl^eq < 30, over distance scales ~10 Mpc.Comment: Submitted to JCA
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