Predation among supermarkets: An algorithmic locational analysis

First an algorithm that finds certain polygonal tesselations of R² is described; the polygons involved here are market areas of supermarkets in a city, defined by prices and transport cost proportional to Euclidean distance. Then statistics based on the adjacencies, boundaries, and sizes of all market areas (in Edmonton, Canada, during 1959–1973) are used to test hypotheses on locational predation.     

EDUCATION VOUCHERS IN PRINCIPLE AND PRACTICE: A SURVEY

An education voucher system exists when governments make paymentsto families that enable their children to enter public or privateschools of their choice. The tax-funded payments can be madedirectly to parents or indirectly to the selected schools; theirpurpose is to increase parental choice, to promote school competition,and to allow low-income families access to private schools.Some opponents predict that vouchers will destroy the publicsystem, aggravate poverty, and foster segregation. Others fearthat voucher-receiving independent schools will be regulatedout of recognition. The main purpose of this article is to examine the recent emergenceof voucher systems as an interesting phenomenon in its own right.The evidence summarized relates to voucher systems operatingin twenty countries, provinces, and states. The typical "funds-follow-the-child"voucher system, in which governments subsidize "schools of choice"in strict proportion to enrollment, appears to be the favoriteform. This type of voucher has been adopted by developing countries—notablyBangladesh, Belize, Chile, Colombia, Guatemala, and Lesotho—aswell as by industrial countries such as Poland, Sweden, theUnited Kingdom, and the United States. Much of the recordedexperience with such programs is pertinent to the longstandingtheoretical debates on the desirability of voucher systems.      

Use of the prostate specific antigen (P.S.A.) in early detection of prostate cancer in males over the age of 50

A total of 469 males over the age of 50 years were tested by the prostate specific antigen (PSA) with follow-up evaluations on those that exceeded 4.0 ng/ml. Thirty six (7.7 percent) of the participants had abnormal results, 23 (63.9 percent) had abnormal digital rectal examinations (DRE) and had biopsies done. Ten of the 23 biopsied participants had positive findings of prostate malignancy and 16 participants had benign prostatic hyperplasia. Three participants with abnormal PSA had negative DRE and no evidence of malignancy by ultrasound. Based on age-specific reference ranges, only one positive biopsy would have been missed while five of the 16 males who had negative biopsies would not have had to undergo this procedure. This would have resulted in a significant savings of medical costs as well as undue worry by the patient.     

乡味中国年——重温记忆深处的年味

闹社火、造黄酒、踩芦笙、跳木鼓、送财神、祭祖先、舞火龙、打铁花、跑马排、唱花灯、舞狮灯、逛庙会、闹元宵……纯粹的中国年俗,传统的中国年味。     

Student loans in developing countries: government versus company loans

Using data from the International Finance Corporation study on private investment in education, Tooley and West give details of two types of international experience with student loans. In particular they look at the government student loan scheme in Thailand and loan schemes offered by various for-profit and nonprofit education companies in Peru, Colombia and India. Difficulties are pointed out with regard to the government scheme, which it may be possible to alleviate under the company schemes.     

Agents to the Rescue?

The advent of electronic environments is bound to have profound effects on consumer decision making. While the exact nature of these influences is only partially known it is clear that consumers could benefit from properly designed electronic agents that know individual users' preferences and can act on their behalf. An examination of the various roles agents perform is presented as a framework for thinking about the design of electronic agents. In addition, a set of goals is established that include both outcome-based measures, such as improving decision quality, as well as process measures like increasing satisfaction and developing trust.     

Using a Community of Knowledge to Build Intelligent Agents

The modeling of individual consumer preference can be aided by incorporating others' opinions which contain information above and beyond identified product attributes. The value of others' opinions is tested using two empirical data sets. The results indicate that incorporating others' opinions into an attribute-based model can reduce systematic error and increase predictive accuracy by serving as a proxy for missing information (e.g., undiscovered attributes or attribute interactions, sensory or experiential aspects of the product, as well as advertising or word of mouth effects). Additionally, modeling individual preference based on others' opinions alone is shown to predict as well or better than traditional multiattribute models thus bypassing the need for defining a product attribute space.     

The Evolution and Devolution of Bank Regulation in the United States

Development economics is understood as a postwar phenomenon without antecedents. Yet, Veblen's contribution to development economics was once widely disseminated and acknowledged. Veblen's evolutionary economics centered on historically relative and limited truths applicable to specific cultures. Veblen's growth theory is a theory of economic development: quantitative accumulation is significant because it engenders qualitative change. Veblen's analysis of the harnessing of the economic potential centers on the ability of a society to successfully introduce scientific and technological advances, giving rise to increasing returns as the surplus is invested in industrial activities. Veblen presented oblique comments and startling insights in a non-empirical manner.