The formation of low-ionization emission in the halo of NGC 891

Imaging and Spectroscopic study first revealed the presence of a diffuse ionized medium (DIM), having unusual excitation, pervading the lower halo of the edge-on spiral galaxy NGC 891. Emission from this DIM is strongest northeast of the nucleus, at radii between 2 and 8 kpc (hereafter region 1). The (N2)(lambda)6583/H(alpha) and (S2)(lambda) (lambda)6716,6731/H(alpha) ratios increase dramatically with z in region 1, from 0.6 and 0.5 respectively at z is approximately equal to 500 pc to 1.1 and 1.0 at z is approximately equal to 1 kpc, while nondetections of (O1)(lambda)6300 and (O3)(lambda)5007 emission yield upper limits of (O1)(lambda)6300/H(alpha) less than or equal to 0.05 and (O3)(lambda)5007/H(alpha) less than or equal to 0.15 for z less than 1 kpc. Previous photoionization models, using the radiation field from disk O and B stars, have been successful in reproducing the elevated (N2)(lambda)6583/H(alpha) and (S2)(lambda)(lambda)6716.6731/H(alpha) ratios observed. However, these radiation bounded models also produce significant (O3)(lambda)5007 emission, in conflict with the observed upper limit. Here, we report the results of new, matter bounded models for the photoionization of the DIM in region 1 of NGC 891

Carry Me Back to Old Virginny / music by James Bland; words by James Bland; revised and edited by Harold Potter

Cover: drawing of an African American female picking cotton; Publisher: Morris Music (Philadelphia)https://egrove.olemiss.edu/sharris_e/1031/thumbnail.jp

Calculation of viscous effects on transonic flow for oscillating airfoils and comparisons with experiment

A method is described for calculating unsteady transonic flow with viscous interaction by coupling a steady integral boundary-layer code with an unsteady, transonic, inviscid small-disturbance computer code in a quasi-steady fashion. Explicit coupling of the equations together with viscous -inviscid iterations at each time step yield converged solutions with computer times about double those required to obtain inviscid solutions. The accuracy and range of applicability of the method are investigated by applying it to four AGARD standard airfoils. The first-harmonic components of both the unsteady pressure distributions and the lift and moment coefficients have been calculated. Comparisons with inviscid calcualtions and experimental data are presented. The results demonstrate that accurate solutions for transonic flows with viscous effects can be obtained for flows involving moderate-strength shock waves

Survey of Generalized Contact Structures

A generalized complex structure, as introduced by N. Hitchin, is a common generalization of both symplectic and complex structures. Generalized complex geometry provides a natural geometric framework to understand certain recent developments in string physics, and has developed into an active area of research. Very recently, an odd dimensional analogue of a generalized complex structure, namely a generalized contact structure, has been introduced in the works of Vaizman, Poon and Wade. In this thesis, we survey the recent works on generalized contact structures. More importantly, we prove a local normal form theorem of a generalized contact structure. This result, which is a joint work with Yi Lin, is original

Three essays in economics

How Many Games Are We Playing: An Experimental Analysis of Choice Bracketing in Games A subject brackets two decisions if she choose[s] an option in each case without full regard to the other Rabin (2009). Although in most situations such behavior is unlikely to be optimal, it is well documented in experiments where subjects make decisions in the absence of strategic considerations. This paper uses an economic experiment to investigate whether subjects also bracket their decisions in games. Subjects played two Volunteer\u27s Dilemmas at the same time, with the payoffs from both games added to their earnings. In a lottery task, subjects were generally revealed to be risk-averse narrow bracketers. Aggregate play in the Roommate\u27s Dilemma is not consistent with predictions made by assuming all subjects either narrowly or broadly bracket. On the individual level, structural modeling suggests that most subjects bracket narrowly in the game. Mixture Models of Behavior and Nuisance Parameters: A Semi-Parametric Bayesian Approach When there is more than one model of decision-making that could explain behavior in experiments, the mixture model is a useful tool in taking theory to data. The estimation results can inform the researcher about the prevalence of each model in the sample, and whether observable characteristics of subjects are predictors of which model they use. Each model typically specifies a function describing behavior, but also requires individual-level nuisance parameters\u27\u27 that must also be estimated. We demonstrate that restrictive econometric assumptions made on these individual parameters can result in the researcher overstating the importance of type heterogeneity (subjects using different decision rules), when in fact the cause of heterogeneous choices is subject parameter heterogeneity (subjects having different nuisance parameters). We propose a less restrictive assumption, and demonstrate its implementation on some existing experimental data. Hospital-Insurer Bargaining Power and Negotiated Rates. In addition to risk-sharing, U.S. health insurance companies negotiate rates for services with hosptials. The price of service can vary depending on which entity, if any, is insuring the patient. Insurers (and possibly their customers) benefit from negotiating through lower prices, while hospitals benefit through higher patient volume. Using Massachusetts\u27 Center for Health Information and Analysis (CHIA) data, we use hospital and insurer characteristics to estimate negotiated prices specific to hospital-insurer pairs. We investigate the relationship between two important quantities: (i) the charged amount that hospitals bill for their services, and (ii) the amount that hospitals are paid for insured patients. These numbers differ because the former is a function only of the services provided and the hospital\u27s chargemaster\u27\u27 prices, while the latter is the result of negotiation. We find that payments for privately insured patients are on average 38% of charges when payments are made on a fee-for-service basis. However this ratio varies greatly by hospital and insurer. Compared to community hospitals without an emergency room, academic medical centers are compensated 15% more for their services, and hospitals with an emergency room are compensated 7% more than those without

Three essays in economics

How Many Games Are We Playing: An Experimental Analysis of Choice Bracketing in Games A subject brackets two decisions if she choose[s] an option in each case without full regard to the other Rabin (2009). Although in most situations such behavior is unlikely to be optimal, it is well documented in experiments where subjects make decisions in the absence of strategic considerations. This paper uses an economic experiment to investigate whether subjects also bracket their decisions in games. Subjects played two Volunteer\u27s Dilemmas at the same time, with the payoffs from both games added to their earnings. In a lottery task, subjects were generally revealed to be risk-averse narrow bracketers. Aggregate play in the Roommate\u27s Dilemma is not consistent with predictions made by assuming all subjects either narrowly or broadly bracket. On the individual level, structural modeling suggests that most subjects bracket narrowly in the game. Mixture Models of Behavior and Nuisance Parameters: A Semi-Parametric Bayesian Approach When there is more than one model of decision-making that could explain behavior in experiments, the mixture model is a useful tool in taking theory to data. The estimation results can inform the researcher about the prevalence of each model in the sample, and whether observable characteristics of subjects are predictors of which model they use. Each model typically specifies a function describing behavior, but also requires individual-level nuisance parameters\u27\u27 that must also be estimated. We demonstrate that restrictive econometric assumptions made on these individual parameters can result in the researcher overstating the importance of type heterogeneity (subjects using different decision rules), when in fact the cause of heterogeneous choices is subject parameter heterogeneity (subjects having different nuisance parameters). We propose a less restrictive assumption, and demonstrate its implementation on some existing experimental data. Hospital-Insurer Bargaining Power and Negotiated Rates. In addition to risk-sharing, U.S. health insurance companies negotiate rates for services with hosptials. The price of service can vary depending on which entity, if any, is insuring the patient. Insurers (and possibly their customers) benefit from negotiating through lower prices, while hospitals benefit through higher patient volume. Using Massachusetts\u27 Center for Health Information and Analysis (CHIA) data, we use hospital and insurer characteristics to estimate negotiated prices specific to hospital-insurer pairs. We investigate the relationship between two important quantities: (i) the charged amount that hospitals bill for their services, and (ii) the amount that hospitals are paid for insured patients. These numbers differ because the former is a function only of the services provided and the hospital\u27s chargemaster\u27\u27 prices, while the latter is the result of negotiation. We find that payments for privately insured patients are on average 38% of charges when payments are made on a fee-for-service basis. However this ratio varies greatly by hospital and insurer. Compared to community hospitals without an emergency room, academic medical centers are compensated 15% more for their services, and hospitals with an emergency room are compensated 7% more than those without

Influence of the active nucleus on the multiphase interstellar medium in NGC 1068

The luminous spiral NGC 1068 has now been imaged from x-ray to radio wavelengths at comparably high resolution (approximately less than 5 in. FWHM). The bolometric luminosity of this well-known Seyfert is shared almost equally between the active nucleus and an extended 'starburst' disk. In an ongoing study, we are investigating the relative importance of the nucleus and the disk in powering the wide range of energetic activity observed throughout the galaxy. Our detailed analysis brings together a wealth of data: ROSAT HRI observations, VLA lambda lambda 6-20 cu cm and OVRO interferometry, lambda lambda 0.4-10.8 micron imaging, and Fabry-Perot spectrophotometry

Carry Me Back to Old Virginny / music by James A. Bland; words by James A. Bland

Cover: drawing of African Americans hanging out next to a building, one man is playing a banjo (see 336); Publisher: Boston-Oliver Ditson Company (New York)https://egrove.olemiss.edu/sharris_b/1065/thumbnail.jp

In The Morning By The Bright Light : A Famous End Song

https://digitalcommons.library.umaine.edu/mmb-vp/1877/thumbnail.jp

Collaborative Action Retreat Report: Summary of Retreat Held in June 2015

No abstract available