7,352 research outputs found
W. Lewis Civil War letter
No full textThis collection contains a letter written in November 1864 by W. Lewis, then stationed at DeValls, Bluff, Ark. The author is believed to be Walter Lewis of Company F of the 20th Iowa Infantry
Michael Lewis: Journalist and Bestselling Author
No full textMichael Lewis is a New York Times bestselling author who has written more than a dozen books on subjects ranging from politics to Wall Street. His recently released book, Fifth Risk, explores mismanagement in federal government.
His other books include The Big Short, Moneyball and The Blind Side - all of which were made into movies. Another, Liar\u27s Poker, was based partly on his experience as a bond salesman at Salomon Brothers.
Lewis is a sharp observer of politics, finance and the evolution of American culture, combining keen insight with a sharp sense of humor. He is a columnist for Bloomberg News and a contributing writer to Vanity Fair. His articles have also appeared in The New York Times Magazine, The New Yorker and Sports Illustrated
THREE-DIMENSIONAL ATMOSPHERIC CIRCULATION OF WARM AND HOT JUPITERS: EFFECTS OF ORBITAL DISTANCE, ROTATION PERIOD, AND NONSYNCHRONOUS ROTATION
No full textEfforts to characterize extrasolar giant planet (EGP) atmospheres have so far emphasized planets within 0.05 AU of their stars. Despite this focus, known EGPs populate a continuum of orbital separations from canonical hot Jupiter values (0.03–0.05 AU) out to 1 AU and beyond. Unlike typical hot Jupiters, these more distant EGPs will not generally be synchronously rotating. In anticipation of observations of this population, we here present three-dimensional atmospheric circulation models exploring the dynamics that emerge over a broad range of rotation rates and incident stellar fluxes appropriate for warm and hot Jupiters. We find that the circulation resides in one of two basic regimes. On typical hot Jupiters, the strong day–night heating contrast leads to a broad, fast superrotating (eastward) equatorial jet and large day–night temperature differences. At faster rotation rates and lower incident fluxes, however, the day–night heating gradient becomes less important, and baroclinic instabilities emerge as a dominant player, leading to eastward jets in the midlatitudes, minimal temperature variations in longitude, and, often, weak winds at the equator. Our most rapidly rotating and least irradiated models exhibit similarities to Jupiter and Saturn, illuminating the dynamical continuum between hot Jupiters and the weakly irradiated giant planets of our own solar system. We present infrared (IR) light curves and spectra of these models, which depend significantly on incident flux and rotation rate. This provides a way to identify the regime transition in future observations. In some cases, IR light curves can provide constraints on the rotation rate of nonsynchronously rotating planets.United States. National Aeronautics and Space Administration (NASA Origins and Planetary Atmospheres grant NNX12AI79G))United States. National Aeronautics and Space Administration (NASA Origins and Planetary Atmospheres grant NNX10AB91G
Early Risk, Attention, and Brain Activation in Adolescents Born Preterm
No full textThe relations among early cumulative medical risk, cumulative environmental risk, attentional control, and brain activation were assessed in 15 – 16-year-old adolescents who were born preterm. Functional magnetic resonance imaging found frontal, temporal, and parietal cortex activation during an attention task with greater activation of the left superior-temporal and left supramarginal gyri associated with better performance. Individual differences in early cumulative risk are related to patterns of brain activation such that medical risk is related to left parietal cortex activation and environmental risk is related to temporal lobe activation. The findings suggest that early risk is related to less mature patterns of brain activation, including reduced efficiency of processing and responding to stimuli.This is the accepted version of the following article: Carmody, D. P., Bendersky, M., Dunn, S. M., DeMarco, J. K., Hegyi, T., Hiatt, M. and Lewis, M. (2006), Early Risk, Attention, and Brain Activation in Adolescents Born Preterm. Child Development, 77: 384–394, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1111/j.1467-8624.2006.00877.x/abstract.Peer reviewe
A SEMI-ANALYTICAL MODEL OF VISIBLE-WAVELENGTH PHASE CURVES OF EXOPLANETS AND APPLICATIONS TO KEPLER-7 B AND KEPLER-10 B
No full textKepler has detected numerous exoplanet transits by measuring stellar light in a single visible-wavelength band. In addition to detection, the precise photometry provides phase curves of exoplanets, which can be used to study the dynamic processes on these planets. However, the interpretation of these observations can be complicated by the fact that visible-wavelength phase curves can represent both thermal emission and scattering from the planets. Here we present a semi-analytical model framework that can be applied to study Kepler and future visible-wavelength phase curve observations of exoplanets. The model efficiently computes reflection and thermal emission components for both rocky and gaseous planets, considering both homogeneous and inhomogeneous surfaces or atmospheres. We analyze the phase curves of the gaseous planet Kepler-7 b and the rocky planet Kepler-10 b using the model. In general, we find that a hot exoplanet's visible-wavelength phase curve having a significant phase offset can usually be explained by two classes of solutions: one class requires a thermal hot spot shifted to one side of the substellar point, and the other class requires reflective clouds concentrated on the same side of the substellar point. Particularly for Kepler-7 b, reflective clouds located on the west side of the substellar point can best explain its phase curve. The reflectivity of the clear part of the atmosphere should be less than 7% and that of the cloudy part should be greater than 80%, and the cloud boundary should be located at 11° ± 3° to the west of the substellar point. We suggest single-band photometry surveys could yield valuable information on exoplanet atmospheres and surfaces
THREE-DIMENSIONAL ATMOSPHERIC CIRCULATION OF HOT JUPITERS ON HIGHLY ECCENTRIC ORBITS
No full textOf the over 800 exoplanets detected to date, over half are on non-circular orbits, with eccentricities as high as 0.93. Such orbits lead to time-variable stellar heating, which has major implications for the planet's atmospheric dynamical regime. However, little is known about the fundamental dynamical regime of such planetary atmospheres, and how it may influence the observations of these planets. Therefore, we present a systematic study of hot Jupiters on highly eccentric orbits using the SPARC/MITgcm, a model which couples a three-dimensional general circulation model (the MITgcm) with a plane-parallel, two-stream, non-gray radiative transfer model. In our study, we vary the eccentricity and orbit-average stellar flux over a wide range. We demonstrate that the eccentric hot Jupiter regime is qualitatively similar to that of planets on circular orbits; the planets possess a superrotating equatorial jet and exhibit large day-night temperature variations. As in Showman & Polvani, we show that the day-night heating variations induce momentum fluxes equatorward to maintain the superrotating jet throughout its orbit. We find that as the eccentricity and/or stellar flux is increased (corresponding to shorter orbital periods), the superrotating jet strengthens and narrows, due to a smaller Rossby deformation radius. For a select number of model integrations, we generate full-orbit light curves and find that the timing of transit and secondary eclipse viewed from Earth with respect to periapse and apoapse can greatly affect what we see in infrared (IR) light curves; the peak in IR flux can lead or lag secondary eclipse depending on the geometry. For those planets that have large temperature differences from dayside to nightside and rapid rotation rates, we find that the light curves can exhibit "ringing" as the planet's hottest region rotates in and out of view from Earth. These results can be used to explain future observations of eccentric transiting exoplanets.United States. National Aeronautics and Space Administration (NASA Origins and Planetary Atmospheres grant))United States. National Aeronautics and Space Administration (Harriet P. Jenkins Pre-Doctoral Fellowship Program)
Lewis Phillip Hall, Local Historian and Author
No full textLewis Phillip Hall-local historian and autho
DOPPLER SIGNATURES OF THE ATMOSPHERIC CIRCULATION ON HOT JUPITERS
No full textThe meteorology of hot Jupiters has been characterized primarily with thermal measurements, but recent observations suggest the possibility of directly detecting the winds by observing the Doppler shift of spectral lines seen during transit. Motivated by these observations, we show how Doppler measurements can place powerful constraints on the meteorology. We show that the atmospheric circulation—and Doppler signature—of hot Jupiters splits into two regimes. Under weak stellar insolation, the day-night thermal forcing generates fast zonal jet streams from the interaction of atmospheric waves with the mean flow. In this regime, air along the terminator (as seen during transit) flows toward Earth in some regions and away from Earth in others, leading to a Doppler signature exhibiting superposed blueshifted and redshifted components. Under intense stellar insolation, however, the strong thermal forcing damps these planetary-scale waves, inhibiting their ability to generate jets. Strong frictional drag likewise damps these waves and inhibits jet formation. As a result, this second regime exhibits a circulation dominated by high-altitude, day-to-night airflow, leading to a predominantly blueshifted Doppler signature during transit. We present state-of-the-art circulation models including non-gray radiative transfer to quantify this regime shift and the resulting Doppler signatures; these models suggest that cool planets like GJ 436b lie in the first regime, HD 189733b is transitional, while planets hotter than HD 209458b lie in the second regime. Moreover, we show how the amplitude of the Doppler shifts constrains the strength of frictional drag in the upper atmospheres of hot Jupiters. If due to winds, the ~2 km s[superscript –1] blueshift inferred on HD 209458b may require drag time constants as short as 10[superscript 4]-10[superscript 6] s, possibly the result of Lorentz-force braking on this planet's hot dayside
The Son and the other stars: Christology and cosmology in the imagination of C.S. Lewis
No full textThis dissertation treats the theory and practice of C. S. Lewis's theological imagination,
focussing upon the imaginative use he made of his professional expertise in medieval and
renaissance literature. Its approach is principally expository rather than an evaluative.
Chapter One outlines the centrality of the imagination to a proper understanding of Lewis's
works.
Chapter Two examines Lewis's own theory of imagination and surveys how he practised it
as a literary critic. We compare and contrast Lewis's theory and practice of imagination
with that of his friend, the theologian, Austin Faffer.
Chapter Three looks in more detail at Lewis's imaginative practice, in particular his
fascination with the images supplied by the seven planets of the Ptolemaic cosmos, which
he termed 'spiritual symbols of permanent value'. We analyse what he meant by 'sprit'
and 'symbol'.
Chapter Four introduces the main argument of the dissertation namely that these seven
spiritual symbols structure the works for which Lewis is best known, the seven 'Chronicles
of Narnia'. We claim to have uncovered the governing imaginative blueprint of the septet.
We address Lewis's capacity for and interest in secrecy and consider why this planetary
theme has remained hitherto undetected.
In Chapters Five to Eleven we take the seven planets in turn and trace the use Lewis made
of them through out his writings. We analyse the planetary symbolism undergirding each
Chronicle and conclude each chapter with an exegesis of the Christological message of each
book so understood.
Chapter Twelve examines factors which motivated Lewis to focus his imaginative energies
upon Ptolemaic cosmology and suggests one particular occasioning factor behind the
composition of the Chronicles. In addition, we consider theological and pedagogical reasons
why he kept silent about the planetary theme. We conclude by indicating certain
consequences that our argument has for future readings of these seven works
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