24,504 research outputs found
Main Street Ready-Made: the New Deal Community of Greendale, Wisconsin
Review of: Main Street Ready-Made: The New Deal Community of Greendale, Wisconsin. Alanen, Arnold R. and Eden, Joseph A
Representing air pollution in future energy scenarios
Decarbonisation of a countryâs energy system requires a change in energy supply chains, infrastructure and the introduction of new technologies. These lead to changes in the scale and type of combustion processes, the fuels used, as well as the activities required to supply fuels and operate energy infrastructure. They lead to changes in emission budgets of greenhouse gases and air pollutants that will have environmental and public health impacts. Such impacts can be highly dependent on the location and on the implementation of emerging energy technologies. This study compares the capabilities of tools for describing atmospheric emissions of air pollutants and greenhouse gases in future energy scenarios, for costing them and for cost-optimising deployment strategy. Case studies of technology choices for deploying decentralised CHP and for the uptake of hybrid vehicles are used to illustrate the challenges of representing emerging technologies in these models. The effectiveness of these technologies of reducing emissions budgets, together with synergies and antagonisms between delivering reductions in greenhouse gas emissions and air pollutant budgets are also explored. Recommendations are made on the using of incumbent models to assess air pollution, on the inclusion of novel technologies in energy scenarios and on how modelling systems might be better adapted to represent these. Spatial and temporal resolution are identified as key influences on modelsâ capabilities. In the hybrid vehicles case study, the precise technology options for vehicles â particularly hybrid powertrain architectures â is a key influence on optimising the benefits of atmospheric emissions reduction from future road transport. In the case of decentralised CHP, the surface morphology close to emission sources or in high population density areas will play a major role in impacts and costs of atmospheric emissions.Open Acces
The Century Survey Galactic Halo Project II: Global Properties and the Luminosity Function of Field Blue Horizontal Branch Stars
We discuss a 175 deg^2 spectroscopic survey for blue horizontal branch (BHB)
stars in the Galactic halo. We use the Two Micron All Sky Survey (2MASS) and
the Sloan Digital Sky Survey (SDSS) to select BHB candidates, and find that the
2MASS and SDSS color-selection is 38% and 50% efficient, respectively, for BHB
stars. Our samples include one likely run-away B7 star 6 kpc below the Galactic
plane. The global properties of the BHB samples are consistent with membership
in the halo population: the median metallicity is [Fe/H]=-1.7, the velocity
dispersion is 108 km/s, and the mean Galactic rotation of the BHB stars
3<|z|<15 kpc is -4 +- 30 km/s. We discuss the theoretical basis of the Preston,
Shectman & Beers M_V-color relation for BHB stars, and conclude that intrinsic
shape of the BHB M_V-color relation results from the physics of stars on the
horizontal branch. We calculate the luminosity function for the field BHB star
samples using the Efstathiou, Ellis, & Peterson maximum-likelihood method which
is unbiased by density variations. The field BHB luminosity function exhibits a
steep rise at bright luminosities, a peak between 0.8 < M_V < 1.0, and a tail
at faint luminosities. We compare the field BHB luminosity functions with the
luminosity functions derived from sixteen different globular cluster BHBs.
Kolmogorov-Smirnov tests suggest that field BHB stars and BHB stars in globular
clusters share a common distribution of luminosities, with the exception of
globular clusters with extended BHBs.Comment: 14 pages, including 16 figures, accepted for publication in A
The Evolution of Cuspy Triaxial Galaxies Harboring Central Black Holes
We use numerical simulations to study the evolution of triaxial elliptical
galaxies with central black holes. In contrast to earlier numerical studies
which used galaxy models with central density ``cores,'' our galaxies have
steep central cusps, like those observed in real ellipticals. As a black hole
grows in these cuspy triaxial galaxies, the inner regions become rounder owing
to chaos induced in the orbit families which populate the model. At larger
radii, however, the models maintain their triaxiality, and orbital analyses
show that centrophilic orbits there resist stochasticity over many dynamical
times. While black hole induced evolution is strong in the inner regions of
these galaxies, and reaches out beyond the nominal ``sphere of influence'' of a
black hole, our simulations do not show evidence for a rapid {\it global}
transformation of the host. The triaxiality of observed elliptical galaxies is
therefore not inconsistent with the presence of supermassive black holes at
their centers.Comment: 15 pages, 7 figures (1 color). Accepted for publication in Ap
Alien Registration- Cooke, Arnold R. (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/23973/thumbnail.jp
Alien Registration- Cooke, Arnold R. (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/23973/thumbnail.jp
Building up the Stellar Halo of the Galaxy
We study numerical simulations of satellite galaxy disruption in a potential
resembling that of the Milky Way. Our goal is to assess whether a merger origin
for the stellar halo would leave observable fossil structure in the phase-space
distribution of nearby stars. We show how mixing of disrupted satellites can be
quantified using a coarse-grained entropy. Although after 10 Gyr few obvious
asymmetries remain in the distribution of particles in configuration space,
strong correlations are still present in velocity space. We give a simple
analytic description of these effects, based on a linearised treatment in
action-angle variables, which shows how the kinematic and density structure of
the debris stream changes with time. By applying this description we find that
a single satellite of current luminosity 10^8 L_\sun disrupted 10 Gyr ago
from an orbit circulating in the inner halo (mean apocentre kpc)
would contribute about kinematically cold streams with internal
velocity dispersions below 5 km/s to the local stellar halo. If the whole
stellar halo were built by disrupted satellites, it should consist locally of
300 - 500 such streams. Clear detection of all these structures would require a
sample of a few thousand stars with 3-D velocities accurate to better than 5
km/s. Even with velocity errors several times worse than this, the expected
clumpiness should be quite evident. We apply our formalism to a group of stars
detected near the North Galactic Pole, and derive an order of magnitude
estimate for the initial properties of the progenitor system.Comment: 28 pages, 10 figures, minor changes, matches the version to appear in
MNRAS, Vol. 307, p.495-517 (August 1999
How should we measure psychological resilience in sport performers?
Psychological resilience is important in sport because athletes must constantly withstand a wide range of pressures to attain and sustain high performance. To advance psychologistsĂąâŹâą understanding of this area, there exists an urgent need to develop a sport-specific measure of resilience. The purpose of this paper is to review psychometric issues in resilience research and to discuss the implications for sport psychology. Drawing on the wider general psychology literature to inform the discussion, the narrative is divided into three main sections relating to resilience and its assessment: adversity, positive adaptation, and protective factors. The first section reviews the different ways that adversity has been measured and considers the potential problems of using items with varying degrees of controllability and risk. The second section discusses the different approaches to assessing positive adaptation and examines the issue of circularity pervasive in resilience research. The final section explores the various issues related to the assessment of protective factors drawing directly from current measures of resilience in other psychology sub-disciplines. The commentary concludes with key recommendations for sport psychology researchers seeking to develop a measure of psychological resilience in athletes
Mapping the Galactic Halo. V. Sgr dSph Tidal Debris 60 degrees from the Main Body
As part of the Spaghetti Project Survey (SPS) we have detected a
concentration of giant stars well above expectations for a smooth halo model.
The position (l~350, b~50) and distance (~50 kpc) of this concentration match
those of the Northern over-density detected by SDSS (Yanny et al. 2000, Ivezic
et al. 2000). We find additional evidence for structure at ~80 kpc in the same
direction. We present radial velocities for many of these stars, including the
first published results from the 6.5m Magellan telescope. The radial velocities
for stars in these structures are in excellent agreement with models of the
dynamical evolution of the Sgr dwarf tidal debris, whose center is 60 degrees
away. The metallicity of stars in these streams is lower than that of the main
body of the Sgr dwarf, which may indicate a radial metallicity gradient prior
to disruption.Comment: 10 pages, 3 figures accepted in Astrophysical Journal Letter
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