6,543 research outputs found
Who Makes the Call on Capital Punishment? How \u3cem\u3eRing v. Arizona\u3c/em\u3e Clarifies the Apprendi Rule and the Implications on Capital Sentencing
Great cities look small
Great cities connect people; failed cities isolate people. Despite the
fundamental importance of physical, face-to-face social-ties in the functioning
of cities, these connectivity networks are not explicitly observed in their
entirety. Attempts at estimating them often rely on unrealistic
over-simplifications such as the assumption of spatial homogeneity. Here we
propose a mathematical model of human interactions in terms of a local strategy
of maximising the number of beneficial connections attainable under the
constraint of limited individual travelling-time budgets. By incorporating
census and openly-available online multi-modal transport data, we are able to
characterise the connectivity of geometrically and topologically complex
cities. Beyond providing a candidate measure of greatness, this model allows
one to quantify and assess the impact of transport developments, population
growth, and other infrastructure and demographic changes on a city. Supported
by validations of GDP and HIV infection rates across United States metropolitan
areas, we illustrate the effect of changes in local and city-wide
connectivities by considering the economic impact of two contemporary inter-
and intra-city transport developments in the United Kingdom: High Speed Rail 2
and London Crossrail. This derivation of the model suggests that the scaling of
different urban indicators with population size has an explicitly mechanistic
origin.Comment: 19 pages, 8 figure
Who Makes the Call on Capital Punishment? How \u3cem\u3eRing v. Arizona\u3c/em\u3e Clarifies the Apprendi Rule and the Implications on Capital Sentencing
Hole maximum density droplets of an antidot in strong magnetic fields
We investigate a quantum antidot in the integer quantum Hall regime (the
filling factor is two) by using a Hartree-Fock approach and by transforming the
electron antidot into a system which confines holes via an electron-hole
transformation. We find that its ground state is the maximum density droplet of
holes in certain parameter ranges. The competition between electron-electron
interactions and the confinement potential governs the properties of the hole
droplet such as its spin configuration. The ground-state transitions between
the droplets with different spin configurations occur as magnetic field varies.
For a bell-shape antidot containing about 300 holes, the features of the
transitions are in good agreement with the predictions of a recently proposed
capacitive interaction model for antidots as well as recent experimental
observations. We show this agreement by obtaining the parameters of the
capacitive interaction model from the Hartree-Fock results. An inverse
parabolic antidot is also studied. Its ground-state transitions, however,
display different magnetic-field dependence from that of a bell-shape antidot.
Our study demonstrates that the shape of antidot potential affects its physical
properties significantly.Comment: 12 pages, 11 figure
Recommended from our members
A whole-health-economy approach to antimicrobial stewardship: Analysis of current models and future direction.
Antimicrobial stewardship (AMS) strategies are widely implemented in single healthcare sectors and organisations; however, the extent and impact of integrated AMS initiatives across the whole health economy are unknown.
Assessing degree of integration of AMS across the whole health economy and its impact is essential if we are to achieve a ‘One Health’ approach to addressing antimicrobial resistance (AMR), and therefore we searched systematically for and analysed published examples of integrated AMS initiatives to address this gap.
Application of a system-level framework to analyse integration of AMS initiatives across and within healthcare sectors shows that integration is emerging but needs strengthening.
Findings from a small number of evaluations in high-income countries suggest that antimicrobial prescribing and healthcare-associated infections can be reduced using a multisectoral integrated AMS approach.
More robust research designs to evaluate and understand the impact of multisectoral integrated AMS are needed, particularly with respect to differing health systems in different countries and local organisational contexts.
Our analysis highlights a number of challenges and ways forward for enhancing the delivery of AMS through an integrated approach
X-ray reverberation in 1H0707-495 revisited
The narrow-line Seyfert 1 galaxy 1H0707-495 has previously been identified as
showing time lags between flux variations in the soft- (0.3-1 keV) and
medium-energy (1-4 keV) X-ray bands that oscillate between positive and
negative values as a function of the frequency of the mode of variation. Here
we measure and analyse the lags also between a harder X-ray band (4-7.5 keV)
and the soft and medium bands, using existing XMM-Newton data, and demonstrate
that the entire spectrum of lags, considering both the full energy range,
0.3-7.5 keV, and the full frequency range, 10^-5 < nu < 10^-2 Hz, are
inconsistent with previous claims of arising as reverberation associated with
the inner accretion disk. Instead we demonstrate that a simple reverberation
model, in which scattering or reflection is present in all X-ray bands,
explains the full set of lags without requiring any ad hoc explanation for the
time lag sign changes. The range of time delays required to explain the
observed lags extends up to about 1800 s in the hard band. The results are
consistent with reverberation caused by scattering of X-rays passing through an
absorbing medium whose opacity decreases with increasing energy and that
partially-covers the source. A high covering factor of absorbing and scattering
circumnuclear material is inferred.Comment: Accepted for publication in MNRA
Leukemia risk and relevant benzene exposure period-Re: follow-up time on risk estimates, Am J Ind Med 42:481-489, 2002.
Medium Resolution Near-Infrared Spectra of the Host Galaxies of Nearby Quasars
We present medium resolution near-infrared host galaxy spectra of low
redshift quasars, PG 0844 + 349 (z=0.064), PG 1226 + 023 (z=0.158), and PG
1426+015 (z=0.086). The observations were done by using the Infrared Camera and
Spectrograph (IRCS) at the Subaru 8.2 m telescope. The full width at half
maximum of the point spread function was about 0.3 arcsec by operations of an
adaptive optics system, which can effectively resolve the quasar spectra from
the host galaxy spectra. We spent up to several hours per target and developed
data reduction methods to reduce the systematic noises of the telluric
emissions and absorptions. From the obtained spectra, we identified absorption
features of Mg I (1.503 um), Si I (1.589 um) and CO (6-3) (1.619 um), and
measured the velocity dispersions of PG 0844 + 349 to be 132+/-110 km s-1 and
PG 1426 + 015 to be 264+/-215 km s-1. By using an M_BH-sigma relation of
elliptical galaxies, we derived the black hole (BH) mass of PG 0844+349,
log(M_BH/M_SUN) = 7.7+/-5.5 and PG 1426+015, log(M_BH/M_SUN) = 9.0+/-7.5. These
values are consistent with the BH mass values from broad emission lines with an
assumption of a virial factor of 5.5.Comment: 16 pages, 5 figure
The reverberation signatures of rotating disc winds in active galactic nuclei
The broad emission lines (BELs) in active galactic nuclei (AGN) respond to
ionizing continuum variations. The time and velocity dependence of their
response depends on the structure of the broad-line region: its geometry,
kinematics and ionization state. Here, we predict the reverberation signatures
of BELs formed in rotating accretion disc winds. We use a Monte Carlo radiative
transfer and ionization code to predict velocity-delay maps for representative
high- (C) and low-ionization (H) emission lines in both high- and
moderate-luminosity AGN. Self-shielding, multiple scattering and the ionization
structure of the outflows are all self-consistently taken into account, while
small-scale structure in the outflow is modelled in the micro-clumping
approximation. Our main findings are: (1) The velocity-delay maps of
smooth/micro-clumped outflows often contain significant negative responses.
(2)~The reverberation signatures of disc wind models tend to be rotation
dominated and can even resemble the classic "red-leads-blue" inflow signature.
(3) Traditional "blue-leads-red" outflow signatures can usually only be
observed in the long-delay limit. (4) Our models predict lag-luminosity
relationships similar to those inferred from observations, but systematically
underpredict the observed centroid delays. (5) The ratio between "virial
product" and black hole mass predicted by our models depends on viewing angle.
Our results imply that considerable care needs to be taken in interpreting data
obtained by observational reverberation mapping campaigns. In particular, basic
signatures such as "red-leads-blue", "blue-leads-red" and "blue and red vary
jointly" are not always reliable indicators of inflow, outflow or rotation.
This may help to explain the perplexing diversity of such signatures seen in
observational campaigns to date.Comment: 15 pages, 17 figures, 2 tables. Accepted by MNRAS 20/7/201
The Impact of the Guide Vane on the BIWT System for the Distributed Wind Generation in the Urban Area
This paper reports a study on the impact of the guide vane on the Building Integrated Wind Turbine (BIWT) system for the distributed wind generation in the urban area. The guide vane is combined with the rotor to concentrate and accelerate the incoming wind to drive the turbine for power generation. The improved BIWT system has several advantages over the conventional BIWT system; it does not require the structural reinforcement of the building because it generates electricity based on the wind pressure acting on the building’s wall. Furthermore, the guide vane conceals the rotor from the view of pedestrians to maintain the aesthetic value of the building. The analysis focuses on the installation of the BIWT design at a high-rise building. The study evaluates the wind dynamics characteristic on the building’s wall using the computational fluid dynamics (CFD) software. Consequently, the producible power output is estimated based on the wind dynamics characteristic. The effectiveness of the BIWT with the guide vane is evaluated on the actual wind data measured at Kota Kinabalu, Sandakan and Kudat. The result shows that the guide vane increases the producible power output by 129.09%
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