6,072 research outputs found
Abundance Analysis of the Halo Giant HD122563 with Three-Dimensional Model Stellar Atmospheres
We present a preliminary local thermodynamic equilibrium (LTE) abundance
analysis of the template halo red giant HD122563 based on a realistic,
three-dimensional (3D), time-dependent, hydrodynamical model atmosphere of the
very metal-poor star. We compare the results of the 3D analysis with the
abundances derived by means of a standard LTE analysis based on a classical,
1D, hydrostatic model atmosphere of the star. Due to the different upper
photospheric temperature stratifications predicted by 1D and 3D models, we find
large, negative, 3D-1D LTE abundance differences for low-excitation OH and Fe I
lines. We also find trends with lower excitation potential in the derived Fe
LTE abundances from Fe I lines, in both the 1D and 3D analyses. Such trends may
be attributed to the neglected departures from LTE in the spectral line
formation calculations.Comment: 4 pages, 4 figures, contribution to proceedings for Joint Discussion
10 at the IAU General Assembly, Rio de Janeiro, Brazil, August 200
The Heroic Struggle of Pleasing a Mad King: An Actor’s Exploration of the Earl of Kent in William Shakespeare’s \u3ci\u3eKing Lear\u3c/i\u3e
This thesis is the research and analysis of the creative process I used in the University of Nebraska-Lincoln Johnny Carson School of Theatre and Film’s 2009 production of King Lear. It is comprised of three main parts. Part One: Research explores the life and work of William Shakespeare. Part Two: A Study of King Lear examines the history of King Lear including major themes and performance history. Part Three: Process provides insight to the thought process of an actor while building a character. Additional materials include documentation of the rehearsal and performance, script analysis, and critical responses to the actor’s performance
The Heroic Struggle of Pleasing a Mad King: An Actor’s Exploration of the Earl of Kent in William Shakespeare’s \u3ci\u3eKing Lear\u3c/i\u3e
This thesis is the research and analysis of the creative process I used in the University of Nebraska-Lincoln Johnny Carson School of Theatre and Film’s 2009 production of King Lear. It is comprised of three main parts. Part One: Research explores the life and work of William Shakespeare. Part Two: A Study of King Lear examines the history of King Lear including major themes and performance history. Part Three: Process provides insight to the thought process of an actor while building a character. Additional materials include documentation of the rehearsal and performance, script analysis, and critical responses to the actor’s performance
Fifty Years of College Choice: Social, Political and Institutional Influences on the Decision-Making Process
Explores how the process of choosing colleges has evolved for high school students during the second half of the twentieth century, the factors behind the changes, and the implications of recent developments for postsecondary equity, access, and success
The challenge of policy coordination for sustainable sociotechnical transitions: the case of the zero-carbon homes agenda in England
Emerging in recent research on sociotechnical transitions towards a low-carbon economy is the question of the extent to which such transitions require centralised, intentional coordination by government. Drawing from Hayek's conceptualisation of coordination, I evaluate the effectiveness of policy for low-carbon and zero-carbon homes in England. A detailed analysis is presented of how policy makers address complex choices and trade-offs as well as significant uncertainty. Particular attention is given to those policy decisions which are widely agreed by stakeholders to cause distortive effects. The focus here on the impacts of policy definition and delivery in terms of multiple evaluative criteria can complement and enrich the more process-orientated cross-sector and multilevel analyses that predominate in existing research on policy coordination. Furthermore, the coordination problems identified yield further insights into the actual and potential effectiveness of policy processes in shaping complex sociotechnical transitions
The Stagger-grid: A Grid of 3D Stellar Atmosphere Models - I. Methods and General Properties
We present the Stagger-grid, a comprehensive grid of time-dependent, 3D
hydrodynamic model atmospheres for late-type stars with realistic treatment of
radiative transfer, covering a wide range in stellar parameters. This grid of
3D models is intended for various applications like stellar spectroscopy,
asteroseismology and the study of stellar convection. In this introductory
paper, we describe the methods used for the computation of the grid and discuss
the general properties of the 3D models as well as their temporal and spatial
averages (). All our models were generated with the Stagger-code, using
realistic input physics for the equation of state (EOS) and for continuous and
line opacities. Our ~220 grid models range in Teff from 4000 to 7000K in steps
of 500K, in log g from 1.5 to 5.0 in steps of 0.5 dex, and [Fe/H] from -4.0 to
+0.5 in steps of 0.5 and 1.0 dex. We find a tight scaling relation between the
vertical velocity and the surface entropy jump, which itself correlates with
the constant entropy value of the adiabatic convection zone. The range in
intensity contrast is enhanced at lower metallicity. The granule size
correlates closely with the pressure scale height sampled at the depth of
maximum velocity. We compare the models with widely applied 1D models, as
well as with theoretical 1D hydrostatic models generated with the same EOS and
opacity tables as the 3D models, in order to isolate the effects of using
self-consistent and hydrodynamic modeling of convection, rather than the
classical mixing length theory approach. For the first time, we are able to
quantify systematically over a broad range of stellar parameters the
uncertainties of 1D models arising from the simplified treatment of physics, in
particular convective energy transport. In agreement with previous findings, we
find that the differences can be significant, especially for metal-poor stars.Comment: Accepted for publication in A&A, 31 pages, 29 figure
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