5,714 research outputs found
A Quiet Area Accessibility Metric for the Southampton Urban Agglomeration
This study proposes a new metric that characterises accessibility to âquiet areasâ, as defined
by the Environmental Noise Directive (END), in urban agglomerations by using Geographical
Information System software in conjunction with END noise mapping results. The metric
methodology is shown and it is used to determine lack of access to quiet spaces in social disadvantaged areas in the city of Southampton, United Kingdom. The results can help urban planners to identify districts that need better provision of tranquil spaces and to enforce measures to protect existing quiet areas. The study concludes with a description of the implementation of the quiet area accessibility metric in open source internet urban mapping
tools
Social Deprivation and Accessibility to Quiet Areas in Southampton
It has been suggested that access to so-called âQuiet Areasâ could be beneficial to subjects with health problems. A number of studies have also indicated a correlation between social deprivation and exposure to noisy environments. The European Noise Directive (END) provides a framework for identifying Quiet Areas in urban agglomerations. This study proposes a new indicator that characterises accessibility to quiet spaces, using Geographical Information System software in conjunction with END noise mapping results. This metric is applied to determine correlations between social deprivation and access to quiet areas in the city of Southampton
3D Photoionisation Modelling of NGC 6302
We present a three-dimensional photoionisation and dust radiative transfer
model of NGC 6302, an extreme, high-excitation planetary nebula. We use the 3D
photoionisation code Mocassin} to model the emission from the gas and dust. We
have produced a good fit to the optical emission-line spectrum, from which we
derived a density distribution for the nebula. A fit to the infrared coronal
lines places strong constraints on the properties of the unseen ionising
source. We find the best fit comes from using a 220,000 K hydrogen-deficient
central star model atmosphere, indicating that the central star of this PN may
have undergone a late thermal pulse.
We have also fitted the overall shape of the ISO spectrum of NGC 6302 using a
dust model with a shallow power-law size distribution and grains up to 1.0
micron in size. To obtain a good fit to the infrared SED the dust must be
sufficiently recessed within the circumstellar disk to prevent large amounts of
hot dust at short wavelengths, a region where the ISO spectrum is particularly
lacking. These and other discoveries are helping to unveil many properties of
this extreme object and trace it's evolutionary history.Comment: 8 pages, 4 figures; for the proceedings of "Asymmetric Planetary
Nebuale IV," R. L. M. Corradi, A. Manchado, N. Soker ed
Galactic AGB stars from the IPHAS survey
We present a photometric analysis of the properties of asymptotic giant branch stars identified in the INT Photometric H-alpha Survey (IPHAS) of the northern Galactic plane. Follow-up spectroscopy has revealed that the IPHAS (r - Ha) colour is a valuable diagnostic of the photospheric C/O ratio, and may be used to identify hundreds of carbon and S-type stars
First results of an HÎą based search of classical Be stars in the Perseus Arm and beyond
We investigate a region of the Galactic plane, between 120° ⤠l ⤠140° and-1° ⤠bâ¤+4°, and uncover a population of moderately reddened (E(B-V) ~ 1) classical Be stars within and beyond the Perseus and Outer Arms. 370 candidate emission-line stars (13â˛râ˛16) selected from the Isaac Newton Telescope Photometric Ha Survey of the Northern Galactic plane have been followed up spectroscopically. A subset of these, 67 stars with properties consistent with those of classical Be stars, have been observed at sufficient spectral resolution (δΝ â 2-4 Ă
) at blue wavelengths to narrow down their spectral types. We determine these to a precision estimated to be Âą1 subtype and then we measure reddenings via spectral energy distribution fitting with reference to appropriate model atmospheres. Corrections for contribution to colour excess from circumstellar discs are made using an established scaling to Ha emission equivalent width. Spectroscopic parallaxes are obtained after luminosity class has been constrained via estimates of distances to neighbouring A/F stars with similar reddenings. Overwhelmingly, the stars in the sample are confirmed as luminous classical Be stars at heliocentric distances ranging from 2 kpc up to ~12 kpc. However, the errors are presently too large to enable the cumulative distribution function with respect to distance to distinguish between models placing the stars exclusively in spiral arms, or in a smooth exponentially declining distribution.Peer reviewe
Creativity and destructiveness in art and psychoanalysis
This paper focuses on the creativity of the patient in analysis and compares it to that of the artist. Taking artistsâ descriptions of their practices as its starting point, the paper suggests that the relationship between patient and analyst parallels that between artist and medium. Psychoanalysis and artistic process can both be seen in terms of a complex interplay between oneness and separateness in which aggression and destructiveness play an essential part. The paper includes a discussion of different forms of aggression and destructiveness within the creative process with particular reference to Winnicottâs paper âThe Use of an Objectâ and Rozsika Parkerâs âThe Angel in the Houseâ. It suggests that a consideration of artistsâ creative processes can shed light both on the experience of the patient in analysis and on the role of the analyst in facilitating the development of the patientâs creativity
Scaling in ordered and critical random Boolean networks
Random Boolean networks, originally invented as models of genetic regulatory
networks, are simple models for a broad class of complex systems that show rich
dynamical structures. From a biological perspective, the most interesting
networks lie at or near a critical point in parameter space that divides
``ordered'' from ``chaotic'' attractor dynamics. In the ordered regime, we show
rigorously that the average number of relevant nodes (the ones that determine
the attractor dynamics) remains constant with increasing system size N. For
critical networks, our analysis and numerical results show that the number of
relevant nodes scales like N^{1/3}. Numerical experiments also show that the
median number of attractors in critical networks grows faster than linearly
with N. The calculations explain why the correct asymptotic scaling is observed
only for very large N.Comment: 4 pages, 3 figures; (Re)submitted to Physical Review Letter
Search for exotic baryons in double radiative capture on pionic hydrogen
We report a search for low-lying exotic baryons via double radiative capture
on pionic hydrogen. The data were collected at the TRIUMF cyclotron using the
RMC spectrometer by detecting gamma-ray pairs from pion stops in liquid
hydrogen. No evidence was found to support an earlier claim for exotic baryons
of masses 1004 and 1044 MeV/. We obtain upper limits on the branching
ratios for double radiative capture via these exotic states of and respectively.Comment: 13 pages, 4 figure
A 3D extinction map of the northern Galactic plane based on IPHAS photometry
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. Š: 2014 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.We present a 3D map of extinction in the northern Galactic plane derived using photometry from the INT/WFC Photometric HÎą Survey of the northern Galactic plane. The map has fine angular (~10 arcmin) and distance (100 pc) sampling allied to a significant depth (âł5 kpc). We construct the map using a method based on a hierarchical Bayesian model described in a previous article by Sale. In addition to mean extinction, we also measure differential extinction, which arises from the fractal nature of the interstellar medium, and show that it will be the dominant source of uncertainty in estimates of extinction to some arbitrary position. The method applied also furnishes us with photometric estimates of the distance, extinction, effective temperature, surface gravity, and mass for ~38 million stars. Both the extinction map and the catalogue of stellar parameters are made publicly available via http://www.iphas.org/extinction.Peer reviewe
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