11,333 research outputs found
Relative status and well-being: evidence from U.S. suicide deaths
This paper empirically assesses the theory of interpersonal income comparison using individual level data on suicide deaths in the United States. We model suicide as a choice variable, conditional on exogenous risk factors, reflecting an individual's assessment of current and expected future utility. Our empirical analysis considers whether suicide risk is systematically related to the income of others, holding own income and other individual factors fixed. We estimate proportional hazards and probit models of the suicide hazard using two separate and independent data sets: (1) the National Longitudinal Mortality Study and (2) the Detailed Mortality Files combined with the 5 percent Public Use Micro Sample of the 1990 decennial census. Results from both data sources show that, controlling for own income and individual characteristics, individual suicide risk rises with reference group income. This result holds for reference groups defined broadly, such as by county, and more narrowly by county and one demographic marker (e.g., age, sex, race). These findings are robust to alternative specifications and cannot be explained by geographic variation in cost of living, access to emergency medical care, mismeasurement of deaths by suicide, or by bias due to endogeneity of own income. Our results confirm findings using self-reported happiness data and are consistent with models of utility featuring "external habit" or "Keeping Up with the Joneses" preferences.Income distribution ; Suicide
Measurement of the Nodal Precession of WASP-33 b via Doppler Tomography
We have analyzed new and archival time series spectra taken six years apart
during transits of the hot Jupiter WASP-33 b, and spectroscopically resolved
the line profile perturbation caused by the Rossiter-McLaughlin effect. The
motion of this line profile perturbation is determined by the path of the
planet across the stellar disk, which we show to have changed between the two
epochs due to nodal precession of the planetary orbit. We measured rates of
change of the impact parameter and the sky-projected spin-orbit misalignment of
yr and
~ yr, respectively,
corresponding to a rate of nodal precession of
~ yr. This is only the
second measurement of nodal precession for a confirmed exoplanet transiting a
single star. Finally, we used the rate of precession to set limits on the
stellar gravitational quadrupole moment of
.Comment: Published in ApJL. 5 pages, 3 figures. Corrected error in the
calculation of J_
First Observational Tests of Eternal Inflation
The eternal inflation scenario predicts that our observable Universe resides inside a single bubble embedded in a vast inflating multiverse. We present the first observational tests of eternal inflation, performing a search for cosmological signatures of collisions with other bubble universes in cosmic microwave background data from the WMAP satellite. We conclude that the WMAP 7-year data do not warrant augmenting the cold dark matter model with a cosmological constant with bubble collisions, constraining the average number of detectable bubble collisions on the full sky N̅ _s<1.6 at 68% C.L. Data from the Planck satellite can be used to more definitively test the bubble-collision hypothesis
Measuring Galaxy Star Formation Rates From Integrated Photometry: Insights from Color-Magnitude Diagrams of Resolved Stars
We use empirical star formation histories (SFHs), measured from HST-based
resolved star color-magnitude diagrams, as input into population synthesis
codes to model the broadband spectral energy distributions (SEDs) of ~50 nearby
dwarf galaxies (6.5 < log M/M_* < 8.5, with metallicities ~10% solar). In the
presence of realistic SFHs, we compare the modeled and observed SEDs from the
ultraviolet (UV) through near-infrared (NIR) and assess the reliability of
widely used UV-based star formation rate (SFR) indicators. In the FUV through i
bands, we find that the observed and modeled SEDs are in excellent agreement.
In the Spitzer 3.6micron and 4.5micron bands, we find that modeled SEDs
systematically over-predict observed luminosities by up to ~0.2 dex, depending
on treatment of the TP-AGB stars in the synthesis models. We assess the
reliability of UV luminosity as a SFR indicator, in light of independently
constrained SFHs. We find that fluctuations in the SFHs alone can cause factor
of ~2 variations in the UV luminosities relative to the assumption of a
constant SFH over the past 100 Myr. These variations are not strongly
correlated with UV-optical colors, implying that correcting UV-based SFRs for
the effects of realistic SFHs is difficult using only the broadband SED.
Additionally, for this diverse sample of galaxies, we find that stars older
than 100 Myr can contribute from <5% to100% of the present day UV luminosity,
highlighting the challenges in defining a characteristic star formation
timescale associated with UV emission. We do find a relationship between UV
emission timescale and broadband UV-optical color, though it is different than
predictions based on exponentially declining SFH models. Our findings have
significant implications for the comparison of UV-based SFRs across
low-metallicity populations with diverse SFHs.Comment: 22 pages, 15 figures, ApJ accepte
A robust constraint on cosmic textures from the cosmic microwave background
Fluctuations in the cosmic microwave background (CMB) contain information
which has been pivotal in establishing the current cosmological model. These
data can also be used to test well-motivated additions to this model, such as
cosmic textures. Textures are a type of topological defect that can be produced
during a cosmological phase transition in the early universe, and which leave
characteristic hot and cold spots in the CMB. We apply Bayesian methods to
carry out a rigorous test of the texture hypothesis, using full-sky data from
the Wilkinson Microwave Anisotropy Probe. We conclude that current data do not
warrant augmenting the standard cosmological model with textures. We rule out
at 95% confidence models that predict more than 6 detectable cosmic textures on
the full sky.Comment: 5 pages, 2 figures. v2: replaced with version accepted by PRL (minor
amendments to reduce length and address referee comments
Estimating the Value of Medal Success at the 2010 Winter Olympic Games
We estimate Canadians’ willingness to pay (WTP) for success by Team Canada in the 2010 Winter Olympics. The Canadian government subsidized elite athletes in the run up to the 2010 Games through the Own the Podium program, which was designed to increase Canada’s medal count. WTP estimates from a contingent valuation method (CVM) study using data from nationally representative surveys before and after the Games suggest that Own the Podium generated intangible benefits of between 3 and 5 times its cost. The aggregate value of the intangible benefits generated by the program was between 3.4 billion. Key Words: Olympic Games, contingent valuation method, willingness to pay
Hierarchical Bayesian Detection Algorithm for Early-Universe Relics in the Cosmic Microwave Background
A number of theoretically well-motivated additions to the standard
cosmological model predict weak signatures in the form of spatially localized
sources embedded in the cosmic microwave background (CMB) fluctuations. We
present a hierarchical Bayesian statistical formalism and a complete data
analysis pipeline for testing such scenarios. We derive an accurate
approximation to the full posterior probability distribution over the
parameters defining any theory that predicts sources embedded in the CMB, and
perform an extensive set of tests in order to establish its validity. The
approximation is implemented using a modular algorithm, designed to avoid a
posteriori selection effects, which combines a candidate-detection stage with a
full Bayesian model-selection and parameter-estimation analysis. We apply this
pipeline to theories that predict cosmic textures and bubble collisions,
extending previous analyses by using: (1) adaptive-resolution techniques,
allowing us to probe features of arbitrary size, and (2) optimal filters, which
provide the best possible sensitivity for detecting candidate signatures. We
conclude that the WMAP 7-year data do not favor the addition of either cosmic
textures or bubble collisions to the standard cosmological model, and place
robust constraints on the predicted number of such sources. The expected
numbers of bubble collisions and cosmic textures on the CMB sky within our
detection thresholds are constrained to be fewer than 4.0 and 5.2 at 95%
confidence, respectively.Comment: 34 pages, 18 figures. v3: corrected very minor typos to match
published versio
Instructional Decision-Making among Expert Choral and Instrumental Directors: How Musical Setting Influences Pedagogy
In large music ensembles, directors make countless instructional decisions on a daily basis that indicate their learning priorities and guide student learning. In particular, expert music directors (i.e., those having earned a master’s degree and/or National Board Certification) have advanced problem-solving strategies and effective means of fostering student learning in their ensembles. To explore the influence of musical setting on directors’ instructional decision-making, the authors examined expert choral and instrumental directors’ perspectives on instructional decision-making. Forty experienced music teachers employed as either a choral or instrumental ensemble music teachers wrote open-ended responses to three scenarios, each representing different instructional challenges. Three main themes emerged related to instructional challenges: (1) Pedagogy, (2) Student Motivation, and (3) Classroom Management. Within each theme, the authors articulated multiple topics that revealed similarities and differences between the choral and instrumental settings. Understanding these comparisons and contrasts by musical setting is essential to enhancing teacher education programs. Implications include improving teachers’ self-awareness and advancing professional development opportunities for both choral and instrumental music directors
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