The Mass-Loss Return From Evolved Stars to The Large Magellanic Cloud VI: Luminosities and Mass-Loss Rates on Population Scales

We present results from the first application of the Grid of Red Supergiant and Asymptotic Giant Branch ModelS (GRAMS) model grid to the entire evolved stellar population of the Large Magellanic Cloud (LMC). GRAMS is a pre-computed grid of 80,843 radiative transfer (RT) models of evolved stars and circumstellar dust shells composed of either silicate or carbonaceous dust. We fit GRAMS models to ~30,000 Asymptotic Giant Branch (AGB) and Red Supergiant (RSG) stars in the LMC, using 12 bands of photometry from the optical to the mid-infrared. Our published dataset consists of thousands of evolved stars with individually determined evolutionary parameters such as luminosity and mass-loss rate. The GRAMS grid has a greater than 80% accuracy rate discriminating between Oxygen- and Carbon-rich chemistry. The global dust injection rate to the interstellar medium (ISM) of the LMC from RSGs and AGB stars is on the order of 1.5x10^(-5) solar masses/yr, equivalent to a total mass injection rate (including the gas) into the ISM of ~5x10^(-3) solar masses/yr. Carbon stars inject two and a half times as much dust into the ISM as do O-rich AGB stars, but the same amount of mass. We determine a bolometric correction factor for C-rich AGB stars in the K band as a function of J - K color, BC(K) = -0.40(J-K)^2 + 1.83(J-K) + 1.29. We determine several IR color proxies for the dust mass-loss rate (MLR) from C-rich AGB stars, such as log (MLR) = (-18.90)/((K-[8.0])+3.37)-5.93. We find that a larger fraction of AGB stars exhibiting the `long-secondary period' phenomenon are O-rich than stars dominated by radial pulsations, and AGB stars without detectable mass-loss do not appear on either the first-overtone or fundamental-mode pulsation sequences.Comment: 19 pages, 19 figure

Modern Sentencing Mitigation

Sentencing has become the most important part of a criminal case. Over the past century, criminal trials have given way almost entirely to pleas. Once a case is charged, it almost always ends up at sentencing. And notably, judges learn little sentencing-relevant information about the case or the defendant prior to sentencing and have significant discretion in sentencing decisions. Thus, sentencing is the primary opportunity for the defense to affect the outcome of the case by presenting mitigation: reasons why the nature of the offense or characteristics of the defendant warrant a lower sentence. It is surprising, then, that relatively little scholarship in criminal law focuses on mitigation at sentencing. Fundamental questions have not been explored: Do the Sentencing Guidelines—which largely limit the relevance of mitigating evidence—make mitigation unimportant? Does the extent or type of mitigation offered have any relationship with the sentence imposed? This Article fills that gap by examining a previously unexplored data set: sentencing memoranda filed by defense attorneys in federal felony cases. By systematically parsing categories of mitigating evidence and quantitatively coding the evidence, I show that mitigation is a central predictor of sentencing outcomes and that judges approach mitigation in a modern way: rather than adhering to the strict, offense-centric structure that has dominated sentencing since the advent of the Sentencing Guidelines in the 1980s, judges individualize sentences in ways that consider the personal characteristics of each defendant, beyond what the Guidelines anticipate. And particular types of mitigation, such as science-based arguments about mental and physical health, appear especially persuasive. The results have significant implications for criminal justice policy: while my data show that mitigation is critical to judges’ sentencing decisions, both the Guidelines and procedural rules minimize mitigation, failing to encourage both defense attorneys and prosecutors to investigate and consider it. I suggest reforms to make sentencing more equitable, such as requiring the investigation and presentation of mitigation to constitute effective assistance of counsel, easing the barriers to obtaining relevant information on mental and physical health mitigation, and encouraging prosecutors to consider mitigation in charging decisions and sentencing recommendations

Neuroscience and Mental Competency: Current Uses and Future Potential

One major conundrum in the field of law and neuroscience is that the mental states that are most relevant to legal determinations are often mental states that occurred in the past, and can longer be assessed. Could the defendant, at the time he committed the crime, have had the cognitive capacity to satisfy the required mens rea for the crime charged? Was an individual\u27s tortious conduct intentional or inadvertent? Even if the field of neuroscience eventually gains the ability to provide data relevant to understanding of immediate mental states, those data will be unavailable to legal actors by the time someone is actually interested in gathering them. The issue of mental competency in criminal cases is an exception to this general problem. Unlike most other relevant mental states in the law, competency deals with a criminal defendant\u27s current mental state, during the litigation itself. Surprisingly, however, relatively little scholarship has been written addressing the potential for neuroscience to aid in competency evaluations. We do not have clear data as to how often neuroscience is used in competency evaluations by experts or in hearings conducted by courts. There is virtually no literature discussing how neuroscience data, at our current level of understanding, might be able to aid in determining competency. This article aims to begin to fill that gap, by exploring several ways in which neuroscience could aid in competency determinations

The location, clustering, and propagation of massive star formation in giant molecular clouds

Massive stars are key players in the evolution of galaxies, yet their formation pathway remains unclear. In this work, we use data from several galaxy-wide surveys to build an unbiased dataset of ~700 massive young stellar objects (MYSOs), ~200 giant molecular clouds (GMCs), and ~100 young (<10 Myr) optical stellar clusters (SCs) in the Large Magellanic Cloud. We employ this data to quantitatively study the location and clustering of massive star formation and its relation to the internal structure of GMCs. We reveal that massive stars do not typically form at the highest column densities nor centers of their parent GMCs at the ~6 pc resolution of our observations. Massive star formation clusters over multiple generations and on size scales much smaller than the size of the parent GMC. We find that massive star formation is significantly boosted in clouds near SCs. Yet, whether a cloud is associated with a SC does not depend on either the cloud's mass or global surface density. These results reveal a connection between different generations of massive stars on timescales up to 10 Myr. We compare our work with Galactic studies and discuss our findings in terms of GMC collapse, triggered star formation, and a potential dichotomy between low- and high-mass star formation.Comment: 13 pages, 7 figures, in pres

Morphological Properties of PPNs: Mid-IR and HST Imaging Surveys

We will review our mid-infrared and HST imaging surveys of the circumstellar dust shells of proto-planetary nebulae. While optical imaging indirectly probes the dust distribution via dust-scattered starlight, mid-IR imaging directly maps the distribution of warm dust grains. Both imaging surveys revealed preferencially axisymmetric nature of PPN dust shells, suggesting that axisymmetry in planetary nebulae sets in by the end of the asymptotic giant branch phase, most likely by axisymmetric superwind mass loss. Moreover, both surveys yielded two morphological classes which have one-to-one correspondence between the two surveys, indicating that the optical depth of circumstellar dust shells plays an equally important role as the inclination angle in determining the morphology of the PPN shells.Comment: 6 pages + 8 figures, to appear in the proceedings of the conference, "Post-AGB Objects (proto-planetary nebulae) as a Phase of Stellar Evolution", Torun, Poland, July 5-7, 2000, eds. R. Szczerba, R. Tylenda, and S.K. Gorny. Figures have been degraded to minimize the total file siz