1,597 research outputs found
Poverty, inequality, child abuse and neglect: changing the conversation across the UK in child protection?
This article explores the evidence on the relationship between poverty, inequality and child abuse and neglect. It argues for the importance of developing further work on the implications of inequality, in particular, as this is a significantly underdeveloped area of study despite compelling evidence of its pertinence to the harms that children and their families experience. Drawing from the findings of a quantitative study that an 'inverse intervention law' seemed to be in operation with systematic unequal implications for children, the conceptual thinking behind a new qualitative study to explore why and how this law operates is explained. The implications for policy and practice are discussed in order to promote further debate about what is often a neglected or invisible aspect of child protection
Uniqueness properties of the Kerr metric
We obtain a geometrical condition on vacuum, stationary, asymptotically flat
spacetimes which is necessary and sufficient for the spacetime to be locally
isometric to Kerr. Namely, we prove a theorem stating that an asymptotically
flat, stationary, vacuum spacetime such that the so-called Killing form is an
eigenvector of the self-dual Weyl tensor must be locally isometric to Kerr.
Asymptotic flatness is a fundamental hypothesis of the theorem, as we
demonstrate by writing down the family of metrics obtained when this
requirement is dropped. This result indicates why the Kerr metric plays such an
important role in general relativity. It may also be of interest in order to
extend the uniqueness theorems of black holes to the non-connected and to the
non-analytic case.Comment: 30 pages, LaTeX, submitted to Classical and Quantum Gravit
Uniqueness Theorem for Static Black Hole Solutions of sigma-models in Higher Dimensions
We prove the uniqueness theorem for self-gravitating non-linear sigma-models
in higher dimensional spacetime. Applying the positive mass theorem we show
that Schwarzschild-Tagherlini spacetime is the only maximally extended, static
asymptotically flat solution with non-rotating regular event horizon with a
constant mapping.Comment: 5 peges, Revtex, to be published in Class.Quantum Gra
Towards the classification of static vacuum spacetimes with negative cosmological constant
We present a systematic study of static solutions of the vacuum Einstein
equations with negative cosmological constant which asymptotically approach the
generalized Kottler (``Schwarzschild--anti-de Sitter'') solution, within
(mainly) a conformal framework. We show connectedness of conformal infinity for
appropriately regular such space-times. We give an explicit expression for the
Hamiltonian mass of the (not necessarily static) metrics within the class
considered; in the static case we show that they have a finite and well defined
Hawking mass. We prove inequalities relating the mass and the horizon area of
the (static) metrics considered to those of appropriate reference generalized
Kottler metrics. Those inequalities yield an inequality which is opposite to
the conjectured generalized Penrose inequality. They can thus be used to prove
a uniqueness theorem for the generalized Kottler black holes if the generalized
Penrose inequality can be established.Comment: the discussion of our results includes now some solutions of Horowitz
and Myers; typos corrected here and there; a shortened version of this
version will appear in Journal of Mathematical Physic
Uniqueness and non-uniqueness of static vacuum black holes in higher dimensions
We prove the uniqueness theorem for asymptotically flat static vacuum black
hole solutions in higher dimensional space-times. We also construct infinitely
many non-asymptotically flat regular static black holes on the same spacetime
manifold with the same spherical topology.Comment: to appear in Progress of Theoretical Physics Supplement No. 14
A Mass Bound for Spherically Symmetric Black Hole Spacetimes
Requiring that the matter fields are subject to the dominant energy
condition, we establish the lower bound for the
total mass of a static, spherically symmetric black hole spacetime. ( and denote the area and the surface gravity of the horizon,
respectively.) Together with the fact that the Komar integral provides a simple
relation between and the strong energy condition,
this enables us to prove that the Schwarzschild metric represents the only
static, spherically symmetric black hole solution of a selfgravitating matter
model satisfying the dominant, but violating the strong energy condition for
the timelike Killing field at every point, that is, .
Applying this result to scalar fields, we recover the fact that the only black
hole configuration of the spherically symmetric Einstein-Higgs model with
arbitrary non-negative potential is the Schwarzschild spacetime with constant
Higgs field. In the presence of electromagnetic fields, we also derive a
stronger bound for the total mass, involving the electromagnetic potentials and
charges. Again, this estimate provides a simple tool to prove a ``no-hair''
theorem for matter fields violating the strong energy condition.Comment: 16 pages, LATEX, no figure
FUNGIBLE AND COMPATIBLE BIOFUELS: LITERATURE SEARCH, SUMMARY, AND RECOMMENDATIONS
The purpose of the study described in this report is to summarize the various barriers to more widespread distribution of bio-fuels through our common carrier fuel distribution system, which includes pipelines, barges and rail, fuel tankage, and distribution terminals. Addressing these barriers is necessary to allow the more widespread utilization and distribution of bio-fuels, in support of a renewable fuels standard and possible future low-carbon fuel standards. These barriers can be classified into several categories, including operating practice, regulatory, technical, and acceptability barriers. Possible solutions to these issues are discussed; including compatibility evaluation, changes to bio-fuels, regulatory changes, and changes in the distribution system or distribution practices. No actual experimental research has been conducted in the writing of this report, but results are used to develop recommendations for future research and additional study as appropriate. This project addresses recognized barriers to the wider use of bio-fuels in the areas of development of codes and standards, industrial and consumer awareness, and materials compatibility issues
THE UNIQUENESS THEOREM FOR ROTATING BLACK HOLE SOLUTIONS OF SELF-GRAVITATING HARMONIC MAPPINGS
We consider rotating black hole configurations of self-gravitating maps from
spacetime into arbitrary Riemannian manifolds. We first establish the
integrability conditions for the Killing fields generating the stationary and
the axisymmetric isometry (circularity theorem). Restricting ourselves to
mappings with harmonic action, we subsequently prove that the only stationary
and axisymmetric, asymptotically flat black hole solution with regular event
horizon is the Kerr metric. Together with the uniqueness result for
non-rotating configurations and the strong rigidity theorem, this establishes
the uniqueness of the Kerr family amongst all stationary black hole solutions
of self-gravitating harmonic mappings.Comment: 18 pages, latex, no figure
Untangling child welfare inequalities and the âInverse Intervention Lawâ in England
This article addresses some potential limitations of key findings from recent research into inequalities in childrenâs social services by providing additional evidence from multilevel models that suggest the socioeconomic social gradient and âInverse Intervention Lawâ in childrenâs services interventions are statistically significant after controlling for possible confounding spatial and population effects. Multilevel negative binomial regression models are presented using English child welfare data to predict the following intervention rates at lower super output area-level: Child in Need (n = 2707, middle super output area [MSOA] n = 543, local authority [LA] n = 13); Child Protection Plan (n = 4115, MSOA n = 837, LA n = 18); and Children Looked After (n = 4115, MSOA n = 837, LA n = 18). We find strong evidence supporting the existence of a steep socioeconomic social gradient in child welfare interventions. Furthermore, we find certain local authority contexts exacerbate this social gradient. Contexts of low overall deprivation and high income inequality are associated with greater socioeconomic inequalities in neighbourhood intervention rates. The relationship between neighbourhood deprivation and children looked after rates is almost five times stronger in local authorities with these characteristics than it is in local authorities with high overall deprivation and low income inequality. We argue that social policy responses addressing structural determinants of child welfare inequalities are needed, and that strategies to reduce the numbers of children taken into care must address underlying poverty and income inequality at both a local and national level
Black hole uniqueness theorems and new thermodynamic identities in eleven dimensional supergravity
We consider stationary, non-extremal black holes in 11-dimensional
supergravity having isometry group . We prove that
such a black hole is uniquely specified by its angular momenta, its electric
charges associated with the various 7-cycles in the manifold, together with
certain moduli and vector valued winding numbers characterizing the topological
nature of the spacetime and group action. We furthermore establish interesting,
non-trivial, relations between the thermodynamic quantities associated with the
black hole. These relations are shown to be a consequence of the hidden
symmetry in this sector of the solution space, and are distinct
from the usual "Smarr-type" formulas that can be derived from the first law of
black hole mechanics. We also derive the "physical process" version of this
first law applicable to a general stationary black hole spacetime without any
symmetry assumptions other than stationarity, allowing in particular arbitrary
horizon topologies. The work terms in the first law exhibit the topology of the
horizon via the intersection numbers between cycles of various dimensions.Comment: 50pp, 3 figures, v2: references added, correction in appendix B,
conclusions added, v3: reference section edited, typos removed, minor changes
in appendix
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