Rate of Collapse of Snow-Bank Kames in Adams Inlet, Southeastern Alaska

Author Institution: Institute of Polar Studies and Department of Geology, The Ohio State University, Columbus, OhioMounds formed by the differential ablation of snow covered by varied thicknesses of sand that has slumped onto a snow bank from an adjacent bluff are here named snow-bank kames. The rate of collapse of these mounds, calculated from temperature observations in the sand and using the temperature-gradient method, was 2.2 cm day-1. The observed rate of lowering for these mounds was between 2.6 and 3.2 cm day-1. The difference in rates may be due to mechanisms of heat transfer other than conduction

Change in Working Length at Different Stages of Instrumentation as a Function of Canal Curvature

The aim of this study was to determine the change in working length (∆WL) before and after coronal flaring and after complete rotary instrumentation as a function of canal curvature. One mesiobuccal or mesiolingual canal from each of 43 extracted molars had coronal standardization and access performed. Once the access was completed, canal preparation was accomplished using Gates Glidden drills for coronal flaring and EndoSequence files for rotary instrumentation. WLs were obtained at 3 time points: pre-instrumentation (unflared), mid-instrumentation (flared) and post-instrumentation (concluded). Measurements were made via direct visualization (DV) and the CanalPro apex locator (EM) in triplicate by a single operator with blinding within the time points. Root curvature was measured using Schneider’s technique. The change in working length was assessed using repeated-measures ANCOVA. The direct visualization measurements were statistically larger than the electronic measurements (paired t-test difference = 0.20 mm, SE = 0.037, P \u3c .0001), although a difference this large may not be clinically important. Overall, a greater change in working length was observed in straight canals than in curved canals, and this trend was more pronounced when measured electronically than via direct visualization, especially in the unflared-concluded time points compared with unflared-flared time points. A greater change in working length was also observed in longer canals than in shorter canals.https://scholarscompass.vcu.edu/gradposters/1032/thumbnail.jp

Pricing-to-market in NSW rice export markets

The Ricegrowers’ Cooperative Limited is a single‐desk seller of NSW Japonica rice on the export market. Confidential monthly price data supplied by the Cooperative were used to examine ‘pricing‐to‐market’ in four of its major export markets. The hypothesis of a competitive market was rejected. The Cooperative has been able to vary mark‐ups over different markets and with respect to the importer’s currency in each market. The exchange rate results in particular suggest that the Cooperative has been able to exercise market power to obtain price premiums.Crop Production/Industries, International Relations/Trade,

Probability distributions for economic surplus changes: the case of technical change in the Australian wool industry

Mullen, Alston and Wohlgenant (1989) (MAW) examined the distribution of the benefits of technical change in the Australian wool industry. Their conclusions are revisited by examining the probability distributions of changes in the welfare measures, given uncertainty about their model parameters. Subjective probability distributions are specified for the parameters and correlations among some of the parameters are imposed. Hierarchical distributions are also used to model diverse views about the specification of the subjective distributions. A sensitivity elasticity is defined through the estimation of a response surface to measure the sensitivity of the estimated research benefits to individual parameters. MAW’s conclusions are found to be robust under the stochastic approach to sensitivity analysis demonstrated in this article.Livestock Production/Industries,

Évaluation économique des programmes de remplacement de la main d’oeuvre expatriée dans les pays en voie de développement : étude du cas de la Côte-d’Ivoire

This study addresses several problems of educational policy posed by the replacement of highly skilled expatriates in the Ivory Coast's labor force. Conceptualizing expatriate replacement as an import-substitution activity in which Ivorian labor substitutes for previously imported labor services, the authors apply a modified Domestic Resource Cost (DRC) analysis to evaluate Ivorian secondary and university educational programs necessary to train the local labor.This methodology, along with more conventional cost-benefit approach, confirms that education is economically desirable in the Ivory Coast and that resource allocation to the upper secondary level is especially warranted. Lower secondary education is useful in so far as it performs a conduit function for higher levels of training. The importance of university education will probably increase as the occupational-educational structure is upgraded through technological development. Finally, consideration should be given to instituting a system of tuition charges in order to equate social and private rates of return in upper secondary and university education

Improved Coefficient and Variance Estimation in Stable First-Order Dynamic Regression Models

In dynamic regression models the least-squares coefficient estimators are biased in finite samples, and so are the usual estimators for the disturbance variance and for the variance of the coefficient estimators. By deriving the expectation of the initial terms in an expansion of the usual expression for the asymptotic coefficient variance estimator and by comparing these with an approximation to the true variance we find an approximation to the bias in variance estimation from which a bias corrected estimator for the variance readily follows. This is also achieved for a bias corrected coefficient estimator and allows to compare analytically the second-order approximation to the mean squared error of the least-squares estimator and its counterpart for the first-order bias corrected coefficient estimator. Two rather strong results on efficiency gains through bias correction for AR(1) models follow. Illustrative simulation results on the magnitude of bias in coefficient and variance estimation and on the scope for effective bias correction and efficiency improvement are presented for some relevant particular cases of the ARX(1) class of models.

Stardust Entry Reconstruction

An overview of the reconstruction analyses performed for the Stardust capsule entry is described. The results indicate that the actual entry was very close to the pre-entry predictions. The capsule landed 8.1 km north-northwest of the desired target at Utah Test and Training Range. Analyses of infrared video footage and radar range data (obtained from tracking stations) during the descent show that drogue parachute deployment was 4.8 s later than the pre-entry prediction, while main parachute deployment was 19.3 s earlier than the pre-set timer indicating that main deployment was actually triggered by the backup baroswitch. Reconstruction of a best estimated trajectory revealed that the aerodynamic drag experienced by the capsule during hypersonic flight was within 1% of pre-entry predications. Observations of the heatshield support the pre-entry estimates of small hypersonic angles of attack, since there was very little, if any, charring of the shoulder region or the aftbody. Through this investigation, an overall assertion can be made that all the data gathered from the Stardust capsule entry were consistent with flight performance close to nominal pre-entry predictions. Consequently, the design principles and methodologies utilized for the flight dynamics, aerodynamics, and aerothermodynamics analyses have been corroborated