The effect of operator learning rate on shrinkage allowance: An operations research analysis

The determination of reject allowances for job shop set-ups usually considers defects to occur randomly through the production run. It is suggested that most defects arise during and just after the setting-up stage.

An analysis is conducted considering the setting-up stage as a learning process and incorporating the effects of additional set-ups. The analysis is extended to cover the effects of a single production station and a multi-station model, where rejects may occur at any station. The model was tested against a sample of actual jobs in a largo manufacturing company. It was demonstrated that the multistation model using a skill and learning probability distribution was the more adequate model, but experienced judgement achieved slightly better results than this model.     

ETHNIC RESIDENTIAL SEGREGATION BY NATIVITY IN GREAT BRITAIN AND THE UNITED STATES

ABSTRACT: This study examines patterns of ethnic residential integration in Great Britain and the United States. Using data from 2000/2001 censuses from these two countries, we compute segregation indexes for comparably defined ethnic groups by nativity and for specific foreign‐born groups. We find that blacks are much less segregated in Great Britain than in the United States, and black segregation patterns by nativity tend to be consistent with spatial assimilation in the former country (the foreign‐born are more segregated than the native‐born) but not in the latter. Among Asian groups, however, segregation tends to be lower in the United States, and segregation patterns by nativity are more consistent with spatial assimilation in the United States but not in Great Britain. These findings suggest that intergenerational minority disadvantage persists among blacks in the United States and among Asians in Great Britain. We caution, however, that there are important differences in levels of segregation among specific foreign‐born Asian groups, suggesting that assimilation trajectories likely differ by country of origin. Finally, the fact that segregation levels are considerably higher in the United States for a majority of groups, including white foreign‐born groups, suggests that factors not solely related to race or physical appearance drive higher levels of ethnic residential segregation in the United States.     

INVESTORS: THE MISSING PIECE IN THE FORECLOSURE RACIAL GAP DEBATE

ABSTRACT: Foreclosures have become one of the most important problems facing cities and the U.S. economy. However, not all communities are affected equally. Our goal is to better understand factors that affect variation in neighborhood foreclosures in a typical, mid‐sized U.S. city—Louisville, Kentucky. While previous findings indicate that a key explanatory variable leading to rising neighborhood foreclosures is the proportion of racial minorities, our analysis finds that in a fully specified model, race does not predict differences between black and white homeowners. On the other hand, an analysis of investors predicts high foreclosure rates in African‐American neighborhoods. The effect of percent nonwhite is caused by several key intervening variables, including the presence of investor foreclosures, the absence of neighborhood walkability, and the prevalence of high‐cost loans. In the past, walkability and investor behavior have largely been ignored by social scientists studying neighborhood variation in foreclosures and the role of race in rising foreclosures. In this article, we examine how speculation by investors in majority African‐American neighborhoods along with degree of walkability and the concentration of high‐priced loans have contributed to recent increases in foreclosures and variation across neighborhoods. Together, the findings demonstrate that these three factors help to better explain the contemporary causes of greater foreclosures in African‐American neighborhoods.     

PREPARATION, PURIFICATION AND IDENTIFICATION OF 10-OXO-TRANS-8-DECENOIC ACID FROM THE CULTIVATED MUSHROOM, AGARICUS BISPORUS

ABSTRACT A procedure was developed to isolate 10-oxo-trans-8-decenoic acid (ODA) from mushrooms. ODA was produced by homogenizing mushrooms in phosphate buffer with added linoleic acid, extracted from the supernatant after centrifugation, and purified using column and thin-layer chromatography. The purified compound was then characterized using ultraviolet, infrared and mass spectrometry, and nuclear magnetic resonance spectroscopy. The purified compound, containing 97.5% ODA, was a white, waxy solid with a pK_a of 4.68. ODA was soluble in acetone, chloroform, ethanol, ethyl ether, methanol, methylene chloride and water, and slightly soluble in pentane, hexane, heptane and benzene. The TBA test was found to be a viable method for the quantification of ODA.     

Styrene monomer migration as monitored by purge and trap gas chromatography and sensory analysis for polystyrene containers

A plastic-like off-flavor in food packaged in multilayered polystyrene containers was determined to be predominately caused by residual styrene monomer, in conjunction with ethylbenzene, that had diffused into the food product. Purge and trap gas chromatography was used to measure μg/L (ppb) concentrations of styrene monomer that migrated from containers over time. The flavor panel used in this study was able to detect the presence of styrene in apple juice at a concentration of 50 μg/L. A mixture of styrene and ethylbenzene was found to lower the concentration at which an off-flavor could be detected to 25 μg/L. Deionized water stored in containers at various temperatures was analyzed for styrene and ethylbenzene by purge and trap gas chromatography, and the initial data fitted a simple diffusion model showing that styrene pickup was proportional to the square root of time.     

WLADIMIR VON DECHTEREW IS WLADIMIR VON BECHTEREW: A TYPOGRAPHICAL ERROR.

A. SILVERSTEIN'S (SEE 40:11) QUOTATION IN AN ARTICLE IN THIS JOURNAL OF "A SPEECH MADE BY VON DECHTEREW AT THE 3RD INTERNATIONAL CONGRESS OF PSYCHOLOGY" AND ESPER'S STATEMENT IN HIS A HISTORY OF PSYCHOLOGY THAT THE SPEECH WAS MADE BY "WLADIMIR VON DECHTEREW (NOT BECHTEREW)" ARE BASED ON A TYPOGRAPHICAL ERROR IN THE PROCEEDINGS OF THE THIRD INTERNATIONAL CONGRESS. A THOROUGH SEARCH OF RUSSIAN PUBLICATIONS REVEALS NO EVIDENCE OF THE EXISTENCE OF ANY VON DECHTEREW AND THE FACT THAN VON BECHTEREW ATTENDED THE 3RD CONGRESS AND SAID WHAT THE ALLEGED VON DECHTEREW IS QUOTED TO HAVE SAID. SILVERSTEIN'S IMPUTATION IN THE ARTICLE THAT PAVLOV'S SYSTEM OF "HIGHER NERVOUS ACTIVITY" AND RAZRAN'S OWN VIEWS ARE REDUCTIONISTIC IS A MISCONCEPTION. (PsycINFO Database Record (c) 2010 APA, all rights reserved)