2,172 research outputs found
Potential for allocative harm in an environmental justice data tool
Neighborhood-level screening algorithms are increasingly being deployed to
inform policy decisions. We evaluate one such algorithm, CalEnviroScreen -
designed to promote environmental justice and used to guide hundreds of
millions of dollars in public funding annually - assessing its potential for
allocative harm. We observe the model to be sensitive to subjective model
decisions, with 16% of tracts potentially changing designation, as well as
financially consequential, estimating the effect of its positive designations
as a 104% (62-145%) increase in funding, equivalent to \$2.08 billion
(\$1.56-2.41 billion) over four years. We also observe allocative tradeoffs and
susceptibility to manipulation, raising ethical concerns. We recommend
incorporating sensitivity analyses to mitigate allocative harm and
accountability mechanisms to prevent misuse
Brief for Respondents. Tyson Foods, Inc. v. Bouaphakeo, 136 S.Ct. 1036 (2016) (No. 14-1146), 2015 WL 5634431
QUESTIONS PRESENTED
1. Whether, in this class and collective action for wage-and-hour violations arising out of an employer\u27s failure properly to compensate employees for time spent donning and doffing protective equipment and walking between sites where work was performed, the district court abused its discretion in granting certification where plaintiffs proceeded to prove the amount of work they did using individual timesheet evidence and representative proof concerning donning, doffing, and walking times in accordance with Anderson v. Mt. Clemens Pottery Co., 328 U.S. 680 (1946).
2. Whether a class or collective action may be certified when it contains members who may not have been injured
Novel coronavirus 2019-nCoV (COVID-19): early estimation of epidemiological parameters and epidemic size estimates
Since it was first identified, the epidemic scale of the recently emerged novel coronavirus (2019-nCoV) in Wuhan, China, has increased rapidly, with cases arising across China and other countries and regions. Using a transmission model, we estimate a basic reproductive number of 3.11 (95% CI, 2.39–4.13), indicating that 58–76% of transmissions must be prevented to stop increasing. We also estimate a case ascertainment rate in Wuhan of 5.0% (95% CI, 3.6–7.4). The true size of the epidemic may be significantly greater than the published case counts suggest, with our model estimating 21 022 (prediction interval, 11 090–33 490) total infections in Wuhan between 1 and 22 January. We discuss our findings in the light of more recent information. This article is part of the theme issue ‘Modelling that shaped the early COVID-19 pandemic response in the UK’
AMiBA: Broadband Heterodyne CMB Interferometry
The Y. T. Lee Array for Microwave Background (AMiBA) has reported the first
science results on the detection of galaxy clusters via the Sunyaev Zel'dovich
effect. The science objectives required small reflectors in order to sample
large scale structures (20') while interferometry provided modest resolutions
(2'). With these constraints, we designed for the best sensitivity by utilizing
the maximum possible continuum bandwidth matched to the atmospheric window at
86-102GHz, with dual polarizations. A novel wide-band analog correlator was
designed that is easily expandable for more interferometer elements. MMIC
technology was used throughout as much as possible in order to miniaturize the
components and to enhance mass production. These designs will find application
in other upcoming astronomy projects. AMiBA is now in operations since 2006,
and we are in the process to expand the array from 7 to 13 elements.Comment: 10 pages, 6 figures, ApJ in press; a version with high resolution
figures available at
http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/mtc_highreso.pd
AMiBA Wideband Analog Correlator
A wideband analog correlator has been constructed for the Yuan-Tseh Lee Array
for Microwave Background Anisotropy. Lag correlators using analog multipliers
provide large bandwidth and moderate frequency resolution. Broadband IF
distribution, backend signal processing and control are described. Operating
conditions for optimum sensitivity and linearity are discussed. From
observations, a large effective bandwidth of around 10 GHz has been shown to
provide sufficient sensitivity for detecting cosmic microwave background
variations.Comment: 28 pages, 23 figures, ApJ in press
AMiBA: scaling relations between the integrated Compton-y and X-ray derived temperature, mass, and luminosity
We investigate the scaling relations between the X-ray and the thermal
Sunyaev-Zel'dovich Effect (SZE) properties of clusters of galaxies, using data
taken during 2007 by the Y.T. Lee Array for Microwave Background Anisotropy
(AMiBA) at 94 GHz for the six clusters A1689, A1995, A2142, A2163, A2261, and
A2390. The scaling relations relate the integrated Compton-y parameter Y_{2500}
to the X-ray derived gas temperature T_{e}, total mass M_{2500}, and bolometric
luminosity L_X within r_{2500}. Our results for the power-law index and
normalization are both consistent with the self-similar model and other studies
in the literature except for the Y_{2500}-L_X relation, for which a physical
explanation is given though further investigation may be still needed. Our
results not only provide confidence for the AMiBA project but also support our
understanding of galaxy clusters.Comment: Accepted by ApJ; 8 pages, 3 figures, 5 table
Mass and Hot Baryons in Massive Galaxy Clusters from Subaru Weak Lensing and AMiBA SZE Observations
We present a multiwavelength analysis of a sample of four hot (T_X>8keV)
X-ray galaxy clusters (A1689, A2261, A2142, and A2390) using joint AMiBA
Sunyaev-Zel'dovich effect (SZE) and Subaru weak lensing observations, combined
with published X-ray temperatures, to examine the distribution of mass and the
intracluster medium (ICM) in massive cluster environments. Our observations
show that A2261 is very similar to A1689 in terms of lensing properties. Many
tangential arcs are visible around A2261, with an effective Einstein radius
\sim 40 arcsec (at z \sim 1.5), which when combined with our weak lensing
measurements implies a mass profile well fitted by an NFW model with a high
concentration c_{vir} \sim 10, similar to A1689 and to other massive clusters.
The cluster A2142 shows complex mass substructure, and displays a shallower
profile (c_{vir} \sim 5), consistent with detailed X-ray observations which
imply recent interaction. The AMiBA map of A2142 exhibits an SZE feature
associated with mass substructure lying ahead of the sharp north-west edge of
the X-ray core suggesting a pressure increase in the ICM. For A2390 we obtain
highly elliptical mass and ICM distributions at all radii, consistent with
other X-ray and strong lensing work. Our cluster gas fraction measurements,
free from the hydrostatic equilibrium assumption, are overall in good agreement
with published X-ray and SZE observations, with the sample-averaged gas
fraction of = 0.133 \pm 0.027, for our sample = (1.2 \pm
0.1) \times 10^{15} M_{sun} h^{-1}. When compared to the cosmic baryon fraction
f_b = \Omega_b/\Omega_m constrained by the WMAP 5-year data, this indicates
/f_b = 0.78 \pm 0.16, i.e., (22 \pm 16)% of the baryons are missing
from the hot phase of clusters.Comment: accepted for publication in ApJ; high resolution figures available at
http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/ms_highreso.pd
The Yuan-Tseh Lee Array for Microwave Background Anisotropy
The Yuan-Tseh Lee Array for Microwave Background Anisotropy (AMiBA) is the
first interferometer dedicated to studying the cosmic microwave background
(CMB) radiation at 3mm wavelength. The choice of 3mm was made to minimize the
contributions from foreground synchrotron radiation and Galactic dust emission.
The initial configuration of seven 0.6m telescopes mounted on a 6-m hexapod
platform was dedicated in October 2006 on Mauna Loa, Hawaii. Scientific
operations began with the detection of a number of clusters of galaxies via the
thermal Sunyaev-Zel'dovich effect. We compare our data with Subaru weak lensing
data in order to study the structure of dark matter. We also compare our data
with X-ray data in order to derive the Hubble constant.Comment: accepted for publication in ApJ (13 pages, 7 figures); a version with
high resolution figures available at
http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/pho_highreso.pd
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