10,194 research outputs found

### Cohort Survival Analysis is Not Enough: Why Local Planners Need to Know More About the Residential Mobility of the Elderly

The residential mobility choices of the elderly (aging-in-place, local moves, or migration) have very different policy implications forming a dynamic system of inter-related issues that present planners with a number of dilemmas which are particularly sensitive to local context. These include competing models of care and service delivery, provision of appropriate housing, physically and socially supportive local environments, community development, relocation services, housing specialization and age integration, the introduction of housing options within neighbourhoods, population redistribution, economic development, social integration, and localized differences in the demand for services. Local planners need to move beyond simple estimates of future demand based expected numbers and present use patterns, to examine the possible impact of these issues on the integration of an aging population within their communities.residential mobility; elderly; planning

### Using fractals and power laws to predict the location of mineral deposits

Around the world the mineral exploration industry is interested in getting that small increase in probability measure on the earth's surface of where the next large undiscovered deposit might be found. In particular WMC Resources Ltd has operations world wide looking for just that edge in the detection of very large deposits of, for example, gold. Since the pioneering work of Mandelbrot, geologists have been familiar with the concept of fractals and self similarity over a few orders of magnitude for geological features. This includes the location and size of deposits within a particular mineral province. Fractal dimensions have been computed for such provinces and similarities of these aggregated measures between provinces have been noted. This paper explores the possibility of making use of known information to attempt the inverse process. That is, from lesser dimensional measures of a mineral province, for example, fractal dimension or more generally multi-fractal measures, is it possible to infer, even with small increase in probability, where the unknown (preferably large) deposits might be located

### How genomic information is accessed in clinical practice: an electronic survey of UK general practitioners.

Genomic technologies are having an increasing impact across medicine, including primary care. To enable their wider adoption and realize their potential, education of primary health-care practitioners will be required. To enable the development of such resources, understanding where GPs currently access genomic information is needed. One-hundred fifty-nine UK GPs completed the survey in response to an open invitation, between September 2017 and September 2018. Questions were in response to 4 clinical genomic scenarios, with further questions exploring resources used for rare disease patients, direct-to-consumer genetic testing and collecting a family history. Respondents were most commonly GP principals (independent GPs who own their clinic) (64.8%), aged 35-49 years (54%), worked as a GP for more than 15 years (44%) and practiced within suburban locations (typically wealthier) (50.3%). The most popular 'just in time' education source for all clinical genomic scenarios were online primary care focussed resources with general Internet search engines also popular. For genomic continuous medical education, over 70% of respondents preferred online learning. Considering specific scenarios, local guidelines were a popular resource for the familial breast cancer scenario. A large proportion (41%) had not heard of Genomics England's 100,000 genome project. Few respondents (4%) would access rare disease specific Internet resources (Orphanet, OMIM). Twenty-five percent of respondents were unsure how to respond to a direct-to-consumer commercial genetic test query, with 41% forwarding such queries to local genetic services. GPs require concise, relevant, primary care focussed resources in trusted and familiar online repositories of information. Inadequate genetic education of GPs could increase burden on local genetic services

### Unified first law of black-hole dynamics and relativistic thermodynamics

A unified first law of black-hole dynamics and relativistic thermodynamics is
derived in spherically symmetric general relativity. This equation expresses
the gradient of the active gravitational energy E according to the Einstein
equation, divided into energy-supply and work terms. Projecting the equation
along the flow of thermodynamic matter and along the trapping horizon of a
blackhole yield, respectively, first laws of relativistic thermodynamics and
black-hole dynamics. In the black-hole case, this first law has the same form
as the first law of black-hole statics, with static perturbations replaced by
the derivative along the horizon. There is the expected term involving the area
and surface gravity, where the dynamic surface gravity is defined as in the
static case but using the Kodama vector and trapping horizon. This surface
gravity vanishes for degenerate trapping horizons and satisfies certain
expected inequalities involving the area and energy. In the thermodynamic case,
the quasi-local first law has the same form, apart from a relativistic factor,
as the classical first law of thermodynamics, involving heat supply and
hydrodynamic work, but with E replacing the internal energy. Expanding E in the
Newtonian limit shows that it incorporates the Newtonian mass, kinetic energy,
gravitational potential energy and thermal energy. There is also a weak type of
unified zeroth law: a Gibbs-like definition of thermal equilibrium requires
constancy of an effective temperature, generalising the Tolman condition and
the particular case of Hawking radiation, while gravithermal equilibrium
further requires constancy of surface gravity. Finally, it is suggested that
the energy operator of spherically symmetric quantum gravity is determined by
the Kodama vector, which encodes a dynamic time related to E.Comment: 18 pages, TeX, expanded somewhat, to appear in Class. Quantum Gra

### Wyman's solution, self-similarity and critical behaviour

We show that the Wyman's solution may be obtained from the four-dimensional
Einstein's equations for a spherically symmetric, minimally coupled, massless
scalar field by using the continuous self-similarity of those equations. The
Wyman's solution depends on two parameters, the mass $M$ and the scalar charge
$\Sigma$. If one fixes $M$ to a positive value, say $M_0$, and let $\Sigma^2$
take values along the real line we show that this solution exhibits critical
behaviour. For $\Sigma^2 >0$ the space-times have eternal naked singularities,
for $\Sigma^2 =0$ one has a Schwarzschild black hole of mass $M_0$ and finally
for $-M_0^2 \leq \Sigma^2 < 0$ one has eternal bouncing solutions.Comment: Revtex version, 15pages, 6 figure

### Construction and enlargement of traversable wormholes from Schwarzschild black holes

Analytic solutions are presented which describe the construction of a
traversable wormhole from a Schwarzschild black hole, and the enlargement of
such a wormhole, in Einstein gravity. The matter model is pure radiation which
may have negative energy density (phantom or ghost radiation) and the
idealization of impulsive radiation (infinitesimally thin null shells) is
employed.Comment: 22 pages, 7 figure

### Quasi-spherical approximation for rotating black holes

We numerically implement a quasi-spherical approximation scheme for computing
gravitational waveforms for coalescing black holes, testing it against angular
momentum by applying it to Kerr black holes. As error measures, we take the
conformal strain and specific energy due to spurious gravitational radiation.
The strain is found to be monotonic rather than wavelike. The specific energy
is found to be at least an order of magnitude smaller than the 1% level
expected from typical black-hole collisions, for angular momentum up to at
least 70% of the maximum, for an initial surface as close as $r=3m$.Comment: revised version, 8 pages, RevTeX, 8 figures, epsf.sty, psfrag.sty,
graphicx.st

### On the semiclassical treatment of Hawking radiation

In the context of the semiclassical treatment of Hawking radiation we prove
the universality of the reduced canonical momentum for the system of a massive
shell self gravitating in a spherical gravitational field within the Painlev\'e
family of gauges. We show that one can construct modes which are regular on the
horizon both by considering as hamiltonian the exterior boundary term and by
using as hamiltonian the interior boundary term. The late time expansion is
given in both approaches and their time Fourier expansion computed to reproduce
the self reaction correction to the Hawking spectrum.Comment: 18 pages, LaTeX, Corrected typo

### Investigating prostate cancer tumour-stroma interactions - clinical and biological insights from an evolutionary game

BACKGROUND: Tumours are made up of a mixed population of different types of cells that include normal structures as well as ones associated with the malignancy, and there are multiple interactions between the malignant cells and the local microenvironment. These intercellular interactions, modulated by the microenvironment, effect tumour progression and represent a largely under appreciated therapeutic target. We use observations of primary tumor biology from prostate cancer to extrapolate a mathematical model: specifically; it has been observed that in prostate cancer three disparate cellular outcomes predominate: (i) the tumour remains well differentiated and clinically indolent - in this case the local stromal cells may act to restrain the growth of the cancer; (ii) early in its genesis the tumour acquires a highly malignant phenotype, growing rapidly and displacing the original stromal population (often referred to as small cell prostate cancer) - these less common aggressive tumours are relatively independent of the local microenvironment; and, (iii) the tumour co-opts the local stroma - taking on a classic stromagenic phenotype where interactions with the local microenvironment are critical to the cancer growth. METHODS: We present an evolutionary game theoretical construct that models the influence of tumour-stroma interactions in driving these outcomes. We consider three characteristic and distinct cellular populations: stromal cells, tumour cells that are self-reliant in terms of microenvironmental factors and tumour cells that depend on the environment for resources but can also co-opt stroma. 
RESULTS: Using evolutionary game theory we explore a number of different scenarios that elucidate the impact of tumour-stromal interactions on the dynamics of prostate cancer growth and progression and how different treatments in the metastatic setting can affect different types of tumors.
CONCLUSIONS: The tumour microenvironment plays a crucial role selecting the traits of the tumour cells that will determine prostate cancer progression. Equally important, treatments like hormone therapy affect the selection of these cancer phenotypes making it very important to understand how they impact prostate cancer’s somatic evolution

- …