The Panchromatic Starburst Intensity Limit At Low And High Redshift

The integrated bolometric effective surface brightness S_e distributions of starbursts are investigated for samples observed in 1. the rest frame ultraviolet (UV), 2. the far-infrared and H-alpha, and 3. 21cm radio continuum emission. For the UV sample we exploit a tight empirical relationship between UV reddening and extinction to recover the bolometric flux. Parameterizing the S_e upper limit by the 90th percentile of the distribution, we find a mean S_{e,90} = 2.0e11 L_{sun}/kpc^2 for the three samples, with a factor of three difference between the samples. This is consistent with what is expected from the calibration uncertainties alone. We find little variation in S_{e,90} with effective radii for R_e ~ 0.1 - 10 kpc, and little evolution out to redshifts z ~ 3. The lack of a strong dependence of S_{e,90} on wavelength, and its consistency with the pressure measured in strong galactic winds, argue that it corresponds to a global star formation intensity limit (\dot\Sigma_{e,90} ~ 45 M_{sun}/kpc^2/yr) rather than being an opacity effect. There are several important implications of these results: 1. There is a robust physical mechanism limiting starburst intensity. We note that starbursts have S_e consistent with the expectations of gravitational instability models applied to the solid body rotation portion of galaxies. 2. Elliptical galaxies and spiral bulges can plausibly be built with maximum intensity bursts, while normal spiral disks can not. 3. The UV extinction of high-z galaxies is significant, implying that star formation in the early universe is moderately obscured. After correcting for extinction, the observed metal production rate at z ~ 3 agrees well with independent estimates made for the epoch of elliptical galaxy formation.Comment: 31 pages Latex (aas2pp4.sty,psfig.sty), 9 figures, accepted for publication in the Astronomical Journa

The linked survival prospects of siblings : evidence for the Indian states

This paper reports an analysis of micro-data for India that shows a high correlation in infant mortality among siblings. In 13 of 15 states, we identify a causal effect of infant death on the risk of infant death of the subsequent sibling (a scarring effect), after controlling for mother-level heterogeneity. The scarring effects are large, the only other covariate with a similarly large effect being mother’s (secondary or higher) education. The two states in which evidence of scarring is weak are Punjab, the richest, and Kerala, the socially most progressive. The size of the scarring effect depends upon the sex of the previous child in three states, in a direction consistent with son-preference. Evidence of scarring implies that policies targeted at reducing infant mortality will have social multiplier effects by helping avoid the death of subsequent siblings. Comparison of other covariate effects across the states offers some interesting new insights

The Panchromatic Starburst Intensity Limit at Low and High Redshift

The integrated bolometric effective surface brightness S distributions of starbursts are investigated for samples observed in (1) the rest frame ultraviolet (UV), (2) the far-infrared and Hα, and (3) 21 cm radio continuum emission. For the UV sample we exploit a tight empirical relationship between UV reddening and extinction to recover the bolometric flux. Parameterizing the S upper limit by the 90th percentile of the distribution, we find a mean S = 2.0×10 L⊙kpc for the three samples, with a factor of 3 difference between the samples. This is consistent with what is expected from the calibration uncertainties alone. We find little variation in S with effective radii for R ∼0.1-10 kpc, and little evolution out to redshifts z≈3. The lack of a strong dependence of S on wavelength, and its consistency with the pressure measured in strong galactic winds, argue that it corresponds to a global star formation intensity limit (Σ ∼45. sript M sign⊙ kpc yr ) rather than being an opacity effect. There are several important implications of these results: (1) There is a robust physical mechanism limiting starburst intensity. We note that starbursts have S consistent with the expectations of gravitational instability models applied to the solid body rotation portion of galaxies. (2) Elliptical galaxies and spiral bulges can plausibly be built with maximum intensity bursts, while normal spiral disks cannot. (3) The UV extinction of high-z galaxies is significant, implying that star formation in the early universe is moderately obscured. After correcting for extinction, the observed metal production rate at z∼3 agrees well with independent estimates made for the epoch of elliptical galaxy formation. © 1997 American Astronomical Society. e e e,90 e,90 e e,90 e,90 e 11 -2 -2 -

Personality Psychology and Economics

This paper explores the power of personality traits both as predictors and as causes of academic and economic success, health, and criminal activity. Measured personality is interpreted as a construct derived from an economic model of preferences, constraints, and information. Evidence is reviewed about the “situational specificity” of personality traits and preferences. An extreme version of the situationist view claims that there are no stable personality traits or preference parameters that persons carry across different situations. Those who hold this view claim that personality psychology has little relevance for economics. The biological and evolutionary origins of personality traits are explored. Personality measurement systems and relationships among the measures used by psychologists are examined. The predictive power of personality measures is compared with the predictive power of measures of cognition captured by IQ and achievement tests. For many outcomes, personality measures are just as predictive as cognitive measures, even after controlling for family background and cognition. Moreover, standard measures of cognition are heavily influenced by personality traits and incentives. Measured personality traits are positively correlated over the life cycle. However, they are not fixed and can be altered by experience and investment. Intervention studies, along with studies in biology and neuroscience, establish a causal basis for the observed effect of personality traits on economic and social outcomes. Personality traits are more malleable over the life cycle compared to cognition, which becomes highly rank stable around age 10. Interventions that change personality are promising avenues for addressing poverty and disadvantage.

Toward a descriptive model of solar particles in the heliosphere

During a workshop on the interplanetary charged particle environment held in 1987, a descriptive model of solar particles in the heliosphere was assembled. This model includes the fluence, composition, energy spectra, and spatial and temporal variations of solar particles both within and beyong 1 AU. The ability to predict solar particle fluences was also discussed. Suggestions for specific studies designed to improve the basic model were also made

Evaluation of the Reggio approach to early education

We evaluate the Reggio Approach using non-experimental data on individuals from the cities of Reggio Emilia, Parma and Padova belonging to one of five age cohorts: ages 50, 40, 30, 18, and 6 as of 2012. The treated were exposed to municipally offered infant-toddler (ages 0–3) and preschool (ages 3–6) programs in Reggio Emilia. The control group either did not receive formal childcare or were exposed to programs offered by municipal systems (outside of Reggio Emilia), or by state or religious systems (in all three cities). We exploit the city-cohort structure of the data to estimate treatment effects using three strategies: difference-in-differences, matching, and matched-difference-in-differences. Most positive and significant effects are generated from comparisons of the treated with individuals who did not receive formal childcare. Relative to not receiving formal care, the Reggio Approach significantly boosts outcomes related to employment, socio-emotional skills, high school graduation, participation in elections, and obesity. Comparisons with individuals exposed to alternative forms of childcare do not yield strong patterns of positive and significant effects. This suggests that differences between the Reggio Approach and other alternatives are not sufficiently large to result in significant differences in outcomes. This interpretation is supported by a survey we conduct, which documents increasing similarities in the administrative and pedagogical practices of childcare systems in the three cities over time

Evaluation of the Reggio approach to early education

We evaluate the Reggio Approach using non-experimental data on individuals from the cities of Reggio Emilia, Parma and Padova belonging to one of five age cohorts: ages 50, 40, 30, 18, and 6 as of 2012. The treated were exposed to municipally offered infant-toddler (ages 0–3) and preschool (ages 3–6) programs in Reggio Emilia. The control group either did not receive formal childcare or were exposed to programs offered by municipal systems (outside of Reggio Emilia), or by state or religious systems (in all three cities). We exploit the city-cohort structure of the data to estimate treatment effects using three strategies: difference-in-differences, matching, and matched-difference-in-differences. Most positive and significant effects are generated from comparisons of the treated with individuals who did not receive formal childcare. Relative to not receiving formal care, the Reggio Approach significantly boosts outcomes related to employment, socio-emotional skills, high school graduation, participation in elections, and obesity. Comparisons with individuals exposed to alternative forms of childcare do not yield strong patterns of positive and significant effects. This suggests that differences between the Reggio Approach and other alternatives are not sufficiently large to result in significant differences in outcomes. This interpretation is supported by a survey we conduct, which documents increasing similarities in the administrative and pedagogical practices of childcare systems in the three cities over time

Faint AGN and the Ionizing Background

We determine the evolution of the faint, high-redshift, optical luminosity function (LF) of AGN implied by several observationally-motivated models of the ionizing background. Our results depend crucially on whether we use the total ionizing rate measured by the proximity effect technique or the lower determination from the flux decrement distribution of Ly alpha forest lines. Assuming a faint-end LF slope of 1.58 and the SDSS estimates of the bright-end slope and normalization, we find that the LF must break at M_B*=-24.2,-22.3, -20.8 at z=3,4, 5 if we adopt the lower ionization rate and assume no stellar contribution to the background. The break must occur at M_B*=-20.6,-18.7, -18.7 for the proximity effect background estimate. These values brighten by as much as ~2 mag if high-z galaxies contribute to the background with an escape fraction of ionizing photons consistent with recent estimates: f_e=0.16. By comparing to faint AGN searches, we find that the typically-quoted proximity effect estimates of the background imply an over-abundance of faint AGN (even with f_e=1). Even adopting the lower bound on proximity effect measurements, the stellar escape fraction must be high: f_e>0.2. Conversely, the lower flux- decrement-derived background requires a limited stellar contribution: f_e<0.05. Our derived LFs together with the locally-estimated black hole density suggest that the efficiency of converting mass to light in optically-unobscured AGN is somewhat lower than expected, <0.05. Comparison with similar estimates based on X-ray counts suggests that more than half of all AGN are obscured in the UV/optical. We also derive lower limits on typical AGN lifetimes and obtain >10^7 yrs for favored cases.Comment: 19 pages, 16 figures. Accepted by Astrophysical Journa

Detectors and cryostat design for the SuMIRe Prime Focus Spectrograph (PFS)

We describe the conceptual design of the camera cryostats, detectors, and detector readout electronics for the SuMIRe Prime Focus Spectrograph (PFS) being developed for the Subaru telescope. The SuMIRe PFS will consist of four identical spectrographs, each receiving 600 fibers from a 2400 fiber robotic positioner at the prime focus. Each spectrograph will have three channels covering wavelength ranges 3800 {\AA} - 6700 {\AA}, 6500 {\AA} - 10000 {\AA}, and 9700 {\AA} - 13000 {\AA}, with the dispersed light being imaged in each channel by a f/1.10 vacuum Schmidt camera. In the blue and red channels a pair of Hamamatsu 2K x 4K edge-buttable CCDs with 15 um pixels are used to form a 4K x 4K array. For the IR channel, the new Teledyne 4K x 4K, 15 um pixel, mercury-cadmium-telluride sensor with substrate removed for short-wavelength response and a 1.7 um cutoff will be used. Identical detector geometry and a nearly identical optical design allow for a common cryostat design with the only notable difference being the need for a cold radiation shield in the IR camera to mitigate thermal background. This paper describes the details of the cryostat design and cooling scheme, relevant thermal considerations and analysis, and discusses the detectors and detector readout electronics