Objective: The widespread adoption of graduated driver licensing (GDL) policies has effectively reduced crash risk for young drivers; however, parents must support, reinforce, and enforce GDL for it to be effective, and research indicates that parents need better information and instruction for adhering to GDL requirements, conducting supervised practice driving, and restricting independent teenage driving. Because teenagers in most states must take driver education to enter the licensing process prior to age 18, integrating parent involvement into driver education may be an effective way to inform and instruct parents on a large scale about teen driver safety. This study assessed parent attitudes (overall and by rural status, minority status, and income level) toward integrating parent involvement into teenage driver education classes.Methods: In this study, 321 parents of teenagers enrolled in driver education classes across the state of Montana completed surveys about current involvement in driver education and attitudes toward required involvement.Results: The results indicated that parents were not very involved currently in their teenagers' driver education classes, but 76% reported that parents should be required to be involved. If involvement were required, parents would prefer having written materials sent home, access to information over the Internet, or discussions in person with the instructor; far fewer would prefer to attend classes or behind-the-wheel driving instruction. There were few differences in parent attitudes by rural or minority status but many by income level. Compared to higher income parents, lower income parents were more likely to endorse required parent involvement in teenage driver education classes and to want parent information from driver education about many teen driving issues.Conclusions: That the majority of parents are open to required involvement in their teenagers' driver education classes is promising because doing so could better prepare parents to understand and adhere to GDL policies, supervise teenagers' practice driving, and manage teen independent driving, all of which could further increase teen driver safety.

Amikacin, an aminoglycoside antimicrobial, was administered to a killer whale (Orcinus orca) and a beluga whale (Delphinapterus leucas) for the treatment of clinical signs consistent with gram-negative aerobic bacterial infections. Dosage regimens were designed to target it maximal plasma concentration 8-10 times the minimum inhibitory concentrations of the pathogen and to reduce the risk of aminoglycoside toxicity. Allometric analysis of published pharmacokinetic parameters in mature animals yielded a relationship for amikacin's volume of distribution, in milliliters, given by the equation Vd = 151.058(BW)(1.043). An initial dose for amikacin was estimated by calculating the volume of distribution and targeted maximal concentration. With this information, dosage regimens for i.m. administration were designed for a killer whale and a beluga whale. Therapeutic drug monitoring was performed on each whale to assess the individual pharmacokinetic parameters. The elimination half-life (5.99 hr), volume of distribution per bioavailability (319 ml/kg), and clearance per bioavailability (0.61 ml/min/kg) were calculated for the killer whale. The elimination half-life (5.03 hr), volume of distribution per bioavailability (229 ml/kg), and clearance per bioavailability (0.53 ml/min/kg) were calculated for the beluga whale. The volume of distribution predicted from the allometric equation for both whales was similar to the calculated pharmacokinetic parameter. Both whales exhibited a prolonged elimination half-life and decreased clearance when compared with other animal species despite normal renal parameters on biochemistry panels. Allometric principles and therapeutic drug monitoring were used to accurately determine the doses in these cases and to avoid toxicity.

The probabilistic model of consumer spatial behavior formulated by Huff in 1962 continues to be used extensively by academicians and professional analysts in a variety of different applications. Consumer patronage, transportation demand, and economic impact are a few examples of such applications. The widespread use of the model has resulted in a number of misuses due to misconceptions and lack of knowledge on key issues. This article highlights key operational problems such as parameter estimation, choice set determination, variable selection and interpretation, and so on. The theoretical underpinning of the model is shown to be rooted in Central Place Theory. © 1997 John Wiley & Sons, Inc.

The Irish urban system has evolved over time. Urban centres have moved up and down the urban hierarchy, and the delineation of urban spheres of influence for the top levels of the urban hierarchy in 1966, 1971 and 1981 indicates that hinterlands have also changed. New centres in the upper tiers of the hierarchy developed in areas where the hinterlands of the older centres in that tier had previously converged. The analysis of such spheres of influences and urban attraction over time can be used as an important aid for a variety of types of government planning.

When the international boundaries in Africa were established in the nineteenth century, they were usually drawn with little or no attention to local circumstances, but rather to meet the needs of diplomats at European conferences. These diplomats were often primarily interested in other parts of the world, and few, if any, of them had set foot on African soil, let alone become familiar with the local conditions on the continent. Similarly, the urban systems within the various African territories were also established with little regard for local circumstances; they were intended to facilitate colonial administration, to provide services for European expatriates, to consolidate control, to exploit mineral or agricultural resources for the metropolitan country, and to achieve other similar goals. The resulting system of urban places, while functional for an overseas dependency, has presented difficulties for independent nations attempting to organize their political and economic space. States of all sizes in different parts of the world face problems in organizing space. Local units of government can become outdated as a result of technological, social, and economic changes. While such problems exist in modern states that have had the opportunity to develop their own internal structures through time, the problem could well be greater in developing countries with shorter periods of independent history. The purpose of the present study is to delineate the spheres of influence of 45 urban places in Ghana based on data from the 1970 census for that country, the most recent for which urban data are available. The derivation of these spheres of influence will provide an indication of the effect of different urban centers upon the Ghanaian countryside and the relationship among the larger urban places. Delineating the structure of the urban system and its relationship to the surrounding countryside will permit the government to make decisions on where to locate services or activities in efforts to develop or integrate the rural areas into the national

Previous research has indicated that emulation is one factor in the spread of policies among the American states. A network analysis was undertaken to identify the possible direct effects of innovative states on their neighbors as well as possible indirect influences on non-contiguous states. The resulting network indicates that some states are leaders for their neighbors and also appear to have additional effects of an indirect nature on more distant states. Cither states appear to serve as transmitters of the propensity to adopt policies from more innovative states.

An application of a relatively new method of depicting multivariate data graphically, this article presents a method developed by Chernoff consisting of representing a point in k-dimensional space as a cartoon of a face. The authors briefly describe the mechanics of constructing a face as well as the geometric relationships involved, illustrate the use of faces as a method of portraying multivariate data graphically, and exemplify the use of this method in detecting subtle, yet potentially significant relationships among variables.

This article presents a method for delineating spheres of influence of urban centers at various levels in an urban hierarchy. The Republic of Ireland provides the geographic setting for the study. The results depict a national set of regions that can be used for serving public interests.

Publisher Summary As the mass of data generated to understand urban and regional problems increases both in terms of variety and complexity, better methods are needed to display, communicate, and analyze such information. The use of graphic displays represents an important and underutilized medium of transmitting information and for exploratory data analysis. Such displays may evoke impressions of underlying relationships that might not easily be detected be mathematical techniques. Therefore, graphic displays serve as methodological aids to hypothesis discovery. The use of computer graphics makes it possible to transform data into a number of different types of geometrical forms. This chapter presents a method of converting multivariate data into faces. The method was originally developed by Chernoff and consists of representing a point in k-dimensional space as a cartoon of a face.

social communication network. The geographic scale within which such diffusion processes occur is localized. While less extensive, there also are some empirical studies that have dealt with the diffusion of innovations within regional and national settings [3; 9; 18; 23]. Characteristically, such studies are concerned with the spread of new techniques, organizations, or ideas over large geographic areas; often the adopting unit is a business, a city, or some other institution. Another distinguishing feature of diffusion processes at this geographic scale is that innovations are thought to filter down the urban hierarchy. By contrast, those at the international scale are extremely small in number, and even fewer deal with the spatial diffusion of political phenomena. However, an excellent opportunity to assess such a diffusion is provided in sub-Saharan Africa where a series of changes in governmental regimes had been brought about by explicit or implicit uses of force. Most of the countries in the sub-Saha-

Huff D. L. (1973) The delineation of a national system of planning regions on the basis of urban spheres of influence. Reg. Studies 7, 323–329. Efforts to provide and coordinate geographically a delivery system for various federal programmes have been severely restricted because of the vast number of political artifacts that characterize the organization of American space. Strong feelings of territoriality associated with these political units have made the achievement of programmes extremely difficult. Competition among political units has been much more characteristic than cooperation. Furthermore, this fragmentation has resulted in duplication, inefficiencies, and higher costs. This paper advances a method of consolidating political units geographically in an effort to alleviate such problems. A distinguishing feature of the method is that it utilizes a spatial model and companion computer programme rather than subjective or empirical procedures. The regions that are delineated represent the spheres of influence of urban places.

Papers in Regional ScienceVolume 20, Issue 1 p. 85-92 GEOMETRIC PROPERTIES OF MARKET AREAS Raymond Gambini, Raymond GambiniSearch for more papers by this authorDavid L. Huff, David L. HuffSearch for more papers by this authorGeorge F. Janks, George F. Janks The authors are associated with the Center for Regional Studies at the University of Kansas.Search for more papers by this author Raymond Gambini, Raymond GambiniSearch for more papers by this authorDavid L. Huff, David L. HuffSearch for more papers by this authorGeorge F. Janks, George F. Janks The authors are associated with the Center for Regional Studies at the University of Kansas.Search for more papers by this author First published: January 1968 https://doi.org/10.1111/j.1435-5597.1968.tb01390.xCitations: 8 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume20, Issue1January 1968Pages 85-92 RelatedInformation

Papers in Regional ScienceVolume 7, Issue 1 p. 19-28 ECOLOGICAL CHARACTERISTICS OF CONSUMER BEHAVIOR David L. Huff, David L. Huff The author is an Assistant Professor of Business Administration of the University of California, Los Angeles. This paper is part of a continuing study to determine the spatial interrelationships between individual traval movements and the location of various types of intra-urban acanomic activities. The author wishes to express his appreciation to the real estate research program of UCIA for its generous support of this research effort.Search for more papers by this author David L. Huff, David L. Huff The author is an Assistant Professor of Business Administration of the University of California, Los Angeles. This paper is part of a continuing study to determine the spatial interrelationships between individual traval movements and the location of various types of intra-urban acanomic activities. The author wishes to express his appreciation to the real estate research program of UCIA for its generous support of this research effort.Search for more papers by this author First published: January 1961 https://doi.org/10.1111/j.1435-5597.1961.tb01768.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume7, Issue1January 1961Pages 19-28 RelatedInformation

Papers in Regional ScienceVolume 6, Issue 1 p. 159-173 A TOPOGRAPHICAL MODEL OF CONSUMER SPACE PREFERENCES David L. Huff, David L. Huff The author is Research Assistant Professor of Real Estate and Urban Land Economics find Assistant Professor in the Marketing in the Graduate School of Business Administration at the University at California at Los Angeles. The work reported upon here was conducted while the author was at the University of Washington. The author wishes to give special thanks to professor William L. Garrison for his constructive criticisms and helpful suggestions concerning the design of this study.Search for more papers by this author David L. Huff, David L. Huff The author is Research Assistant Professor of Real Estate and Urban Land Economics find Assistant Professor in the Marketing in the Graduate School of Business Administration at the University at California at Los Angeles. The work reported upon here was conducted while the author was at the University of Washington. The author wishes to give special thanks to professor William L. Garrison for his constructive criticisms and helpful suggestions concerning the design of this study.Search for more papers by this author First published: January 1960 https://doi.org/10.1111/j.1435-5597.1960.tb01711.xCitations: 45AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Citing Literature Volume6, Issue1January 1960Pages 159-173 RelatedInformation