546 research outputs found
Willingness-to-Pay for Improved Air Quality in Hamilton-Wentworth: A Choice Experiment
Prepared for Hamilton-Wentworth Air Quality Initiative pursuant to a memorandum of understanding among McMaster University, the Ontario Ministry of Environment and Energy and the Regional Municipality of Hamilton-Wentworth, dated November 5, 1996.
The Persistence of Employee 401(k) Contributions Over a Major Stock Market Cycle: Evidence on the Limited Power of Inertia on Savings Behavior
Many middle-income workers save for retirement through 401(k) plans. This study addresses the concern that low account balances of older workers may indicate that these vehicles are not sufficient to insure adequate retirement savings. In particular, the study shows that workers are not persistent (continuing once a worker has started) in contributing, and a weak stock market exacerbates the problem.The study suggests that the concept of inertia, which is in vogue in behavioral economics, does not seem to hold for 401(k) saving behavior. Furthermore, the investment strategy of dollar cost averaging does not seem to hold, either. Using panel data (Panel Study of Income Dynamics) covering a six-year time span from 1999 to 2005, the study presents descriptive and econometric evidence about the persistence behavior of individuals with 401(k) accounts. In particular, the PSID data that were analyzed come from four biannual waves in 1999, 2001, 2003, and 2005. Descriptive data show that of the sample of household heads aged 21-65 in 2005 who were employed in every time period, only about one-third (35 percent) contributed to their plan in all four waves. Job changing had an impact. However, even for individuals in the sample who did not change jobs, less than half (46 percent) contributed in all four years of the survey.An equation modeling 401(k) contribution behavior was estimated using logit regression analysis. When this model was estimated with the sample of individuals who were employed in each panel and with the sample of individuals who were employed in each panel and never changed jobs, the coefficient on the Dow Jones Industrial Average was positive and significant. Workers contributed to their plans when the market was up. This investment error is called herd investing, where individuals get into the market when it is high and not when it is low.The study concludes that the findings have important implications for the pension system and adequacy of retirement income. Projects of future retirement income readiness that assume that workers persistently contribute over their working lives greatly exaggerate the future levels of pension assets workers will have accumulated
The Persistence of Employee 401(k) Contributions Over a Major Stock Market Cycle: Evidence on the Limited Power of Inertia on Savings Behavior
Many middle-income workers save for retirement through 401(k) plans. This study addresses the concern that low account balances of older workers may indicate that these vehicles are not sufficient to insure adequate retirement savings. In particular, the study shows that workers are not persistent (continuing once a worker has started) in contributing, and a weak stock market exacerbates the problem.The study suggests that the concept of inertia, which is in vogue in behavioral economics, does not seem to hold for 401(k) saving behavior. Furthermore, the investment strategy of dollar cost averaging does not seem to hold, either. Using panel data (Panel Study of Income Dynamics) covering a six-year time span from 1999 to 2005, the study presents descriptive and econometric evidence about the persistence behavior of individuals with 401(k) accounts. In particular, the PSID data that were analyzed come from four biannual waves in 1999, 2001, 2003, and 2005. Descriptive data show that of the sample of household heads aged 21-65 in 2005 who were employed in every time period, only about one-third (35 percent) contributed to their plan in all four waves. Job changing had an impact. However, even for individuals in the sample who did not change jobs, less than half (46 percent) contributed in all four years of the survey.An equation modeling 401(k) contribution behavior was estimated using logit regression analysis. When this model was estimated with the sample of individuals who were employed in each panel and with the sample of individuals who were employed in each panel and never changed jobs, the coefficient on the Dow Jones Industrial Average was positive and significant. Workers contributed to their plans when the market was up. This investment error is called herd investing, where individuals get into the market when it is high and not when it is low.The study concludes that the findings have important implications for the pension system and adequacy of retirement income. Projects of future retirement income readiness that assume that workers persistently contribute over their working lives greatly exaggerate the future levels of pension assets workers will have accumulated
The mass and density of the dwarf planet (225088) 2007 OR10
The satellite of (225088) 2007 OR10 was discovered on archival Hubble Space
Telescope images and along with new observations with the WFC3 camera in late
2017 we have been able to determine the orbit. The orbit's notable
eccentricity, e0.3, may be a consequence of an intrinsically eccentric
orbit and slow tidal evolution, but may also be caused by the Kozai mechanism.
Dynamical considerations also suggest that the moon is small, D 100
km. Based on the newly determined system mass of 1.75x10 kg, 2007 OR10
is the fifth most massive dwarf planet after Eris, Pluto, Haumea and Makemake.
The newly determined orbit has also been considered as an additional option in
our radiometric analysis, provided that the moon orbits in the equatorial plane
of the primary. Assuming a spherical shape for the primary this approach
provides a size of 123050 km, with a slight dependence on the satellite
orbit orientation and primary rotation rate chosen, and a bulk density of
1.750.07 g cm for the primary. A previous size estimate that
assumed an equator-on configuration (1535 km) would provide a
density of 0.92 g cm, unexpectedly low for a 1000
km-sized dwarf planet.Comment: Accepted for publication in Icaru
The BAH domain of Rsc2 is a histone H3 binding domain
Bromo-adjacent homology (BAH) domains are commonly found in chromatin-associated proteins and fall into two classes; Remodels the Structure of Chromatin (RSC)-like or Sir3-like. Although Sir3-like BAH domains bind nucleosomes, the binding partners of RSC-like BAH domains are currently unknown. The Rsc2 subunit of the RSC chromatin remodeling complex contains an RSC-like BAH domain and, like the Sir3-like BAH domains, we find Rsc2 BAH also interacts with nucleosomes. However, unlike Sir3-like BAH domains, we find that Rsc2 BAH can bind to recombinant purified H3 in vitro, suggesting that the mechanism of nucleosome binding is not conserved. To gain insight into the Rsc2 BAH domain, we determined its crystal structure at 2.4 Å resolution. We find that it differs substantially from Sir3-like BAH domains and lacks the motifs in these domains known to be critical for making contacts with histones. We then go on to identify a novel motif in Rsc2 BAH that is critical for efficient H3 binding in vitro and show that mutation of this motif results in defective Rsc2 function in vivo. Moreover, we find this interaction is conserved across Rsc2-related proteins. These data uncover a binding target of the Rsc2 family of BAH domains and identify a novel motif that mediates this interaction
Supernova Remnants and Star Formation in the Large Magellanic Cloud
It has often been suggested that supernova remnants (SNRs) can trigger star
formation. To investigate the relationship between SNRs and star formation, we
have examined the known sample of 45 SNRs in the Large Magellanic Cloud to
search for associated young stellar objects (YSOs) and molecular clouds. We
find seven SNRs associated with both YSOs and molecular clouds, three SNRs
associated with YSOs but not molecular clouds, and eight SNRs near molecular
clouds but not associated with YSOs. Among the 10 SNRs associated with YSOs,
the association between the YSOs and SNRs can be either rejected or cannot be
convincingly established for eight cases. Only two SNRs have YSOs closely
aligned along their rims; however, the time elapsed since the SNR began to
interact with the YSOs' natal clouds is much shorter than the contraction
timescales of the YSOs, and thus we do not see any evidence of SNR-triggered
star formation in the LMC. The 15 SNRs that are near molecular clouds may
trigger star formation in the future when the SNR shocks have slowed down to
<45 km/s. We discuss how SNRs can alter the physical properties and abundances
of YSOs.Comment: 24 pages, 5 figures, 1 table, Accepted for publication in the August
2010 edition of the Astronomical Journa
The Magellanic Mopra Assessment (MAGMA). I. The Molecular Cloud Population of the Large Magellanic Cloud
We present the properties of an extensive sample of molecular clouds in the
Large Magellanic Cloud (LMC) mapped at 11 pc resolution in the CO(1-0) line. We
identify clouds as regions of connected CO emission, and find that the
distributions of cloud sizes, fluxes and masses are sensitive to the choice of
decomposition parameters. In all cases, however, the luminosity function of CO
clouds is steeper than dN/dL \propto L^{-2}, suggesting that a substantial
fraction of mass is in low-mass clouds. A correlation between size and
linewidth, while apparent for the largest emission structures, breaks down when
those structures are decomposed into smaller structures. We argue that the
correlation between virial mass and CO luminosity is the result of comparing
two covariant quantities, with the correlation appearing tighter on larger
scales where a size-linewidth relation holds. The virial parameter (the ratio
of a cloud's kinetic to self-gravitational energy) shows a wide range of values
and exhibits no clear trends with the CO luminosity or the likelihood of
hosting young stellar object (YSO) candidates, casting further doubt on the
assumption of virialization for molecular clouds in the LMC. Higher CO
luminosity increases the likelihood of a cloud harboring a YSO candidate, and
more luminous YSOs are more likely to be coincident with detectable CO
emission, confirming the close link between giant molecular clouds and massive
star formation.Comment: Accepted by ApJS; 22 pages in emulateapj format; full-resolution
version and data tables available at http://mmwave.astro.illinois.edu/magma
X-ray emission from the Sombrero galaxy: discrete sources
We present a study of discrete X-ray sources in and around the
bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival
Chandra observations with a total exposure of ~200 ks. With a detection limit
of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30
kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler
et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS
observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray
binaries (LMXBs). We quantify the differential luminosity functions (LFs) for
both the detected GC and field LMXBs, whose power-low indices (~1.1 for the
GC-LF and ~1.6 for field-LF) are consistent with previous studies for
elliptical galaxies. With precise sky positions of the GCs without a detected
X-ray source, we further quantify, through a fluctuation analysis, the GC LF at
fainter luminosities down to 1E35 erg/s. The derived index rules out a
faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent
findings in several elliptical galaxies and the bulge of M31. On the other
hand, the 2-6 keV unresolved emission places a tight constraint on the field
LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101
sources in the halo of Sombrero. The presence of these sources cannot be
interpreted as galactic LMXBs whose spatial distribution empirically follows
the starlight. Their number is also higher than the expected number of cosmic
AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray
surveys. We suggest that either the cosmic X-ray background is unusually high
in the direction of Sombrero, or a distinct population of X-ray sources is
present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
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