bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hormones, Seizures, and Lamotrigine: Oh, My!
Authors: Pennell Page B. 
Published: September 2010

Oral Contraceptives Induce Lamotrigine Metabolism: Evidence from a Double-Blind, Placebo-Controlled Trial. Christensen J, Petrenaite V, Atterman J, Sidenius P, Öhman I, Tomson T, Sabers A. Epilepsia 2007;48(3):484–489. Purpose This study evaluates the effect of oral contraceptives on lamotrigine (LTG) plasma concentrations and urine excretion of LTG metabolites in a double-blind, placebo-controlled, crossover study in patients with epilepsy. Methods Women with epilepsy, treated with LTG in monotherapy and taking combination-type oral contraceptives, were randomized to treatment with placebo or a standard combination-type contraceptive pill. The dose-corrected trough plasma concentration of LTG and the ratio of N-2-glucuronide/unchanged LTG on urine after 21 days of concomitant placebo treatment was analyzed versus those after 21 days of concomitant treatment with the oral contraceptive pill. Results The mean dose-corrected LTG concentration after placebo treatment was 84% [95% confidence interval (CI), 45–134%] higher than after oral contraceptives, signifying an almost doubling of the concentration after cessation of oral contraceptives. Most of this increase took place within the first week after oral contraceptives were stopped. The N-2-glucuronide/LTG ratio in the urine was decreased by 31% (95% CI, −20–61%) when shifting from oral contraceptives to placebo. Conclusions Cessation of oral contraceptives leads to an 84% increase in the concentration of LTG. In parallel, the excretion of the N-2-glucuronide was decreased, indicating that the changes are caused by altered LTG glucuronidation. The change in LTG concentrations was observed within 1 week of the shift of treatment, suggesting that induction and deinduction of LTG glucuronidation is faster than that seen for other metabolic pathways (e.g., cytochrome P450).
On the Implications of a Stationary Urban Population For the Size Distribution of Cities
Authors: Haran E. G. P. , Vining Daniel R. 
Published: September 2010

AbstractThe paper analyzes the limiting case for a modified Yule‐Simon model of city growth. The aim of the paper is primarily to reintroduce geographers to the notion of a closed system of cities, i.e., a system of cities where the aggregate population is stationary in size. The Yule‐Simon model, while successful in dealing with the observed properties of open systems, is seen to break down for closed systems. Moreover, incorporating Simon's assumptions regarding intercity migration into the model produces implausible results.Also, the traditional approach of employing entropy‐maximizing procedures assumes a certain pattern of intercity migration. This pattern, while not inherently implausible, does present features which are questionable. The authors conclude that an adequate theory for closed systems has yet to be developed.
Optimal Facility Location in a One‐Dimensional Spatial Market
Authors: Davies Omar 
Published: September 2010

AbstractThis paper analyzes properties of the optimal spatial arrangement of what may be interpreted as a class of public facilities. Optimality is defined as cost minimization. Three different optimality criteria are considered, and for each, the necessary and, sufficient conditions, market area size, and production levels, are derived. The relationship between optimal production levels and number of facilities needed is also considered. Next the results of implementing various pricing strategies are analyzed with emphasis given to marginal and uniform pricing. It is shown that, given certain conditions, all facilities incur operating deficits, given marginal pricing. Estimates on the level of the deficits are derived in terms of location rents. Finally, in the appendix, several important results from other studies are derived as special cases of the basic model.
Spatial Entropy
Authors: Batty Michael 
Published: September 2010

AbstractA major problem in information theory concerns the derivation of a continuous measure of entropy from the discrete measure. Many analysts have shown that Shannon's treatment of this problem is incomplete, but few have gone on to rework his analysis. In this paper, it is suggested that a new measure of discrete entropy which incorporates interval size explicitly is required; such a measure is fundamental to geography and this statistic has been called spatial entropy. The use of the measure is first illustrated by application to one‐and two‐dimensional aggregation problems, and then the implications of this statistic for Wilson's entropy‐maximizing method are traced. Theil's aggregation statistic is reinterpreted in spatial terms, and finally, some heuristics are suggested for the design of real and idealized spatial systems in which entropy is at a maximum.
The Chromatic Traveling‐Salesmen Problem and Its Application to Planning and Structuring Geographic Space
Authors: Harvey Milton E. , Hocking Ralph T. , Brown J. Randall 
Published: September 2010

AbstractThe classical traveling‐salesman problem involves the establishment of a tour around a set of points in a plane such that each point is intersected only once and the circuit is of minimal total length. When the length of a salesman's tour cannot exceed a specified constant, the problem becomes that of finding the fewest number of salesmen such that every city is visited by a salesman and the length of each salesman's tour does not exceed a specified constant. This is the chromatic traveling‐salesmen problem. An algorithm for this problem is developed and is used to create periodic markets in parts of Sierra Leone. Fifteen rural areas were examined from Sierra Leone, and weekly market places were identified in each area. Salesmen were to be assigned to an area so that each market place was visited and each tour (or periodic ring) did not exceed forty hours. The chromatic traveling‐salesmen algorithm was used to minimize the number of periodic rings needed for each area and provide the specific tour for each ring.
A Three‐State Markov Model of Choice Behavior within Spatial Structures
Authors: Burnett Pat 
Published: September 2010

AbstractThis paper derives a simple mathematical model of spatial learning and choice by integrating several psychological theories, whose features accord with the results of empirical investigation in a previous paper [2]. A sample of homogeneous decision‐makers are assumed to make a succession of selections from a given set of initially unknown spatial alternatives (for example, a set of shopping places for a good). The decision‐makers pass through two states of “recognition” and “discrimination” learning, before reaching an equilibrium state. In the equilibrium state, decision‐makers have sufficiently learned the attributes of the alternatives so that satisfactory choices are always made. These assumptions permit the derivation of mathematical expressions to answer two questions: first, what proportion of decision‐makers will be in the equilibrium state after any given time interval, and second, what proportion of decision‐makers will choose any designated spatial alternative after the same time interval. In the second case, the proportion of decision‐makers choosing an alternative is predicted from the individuals' perceptions of the attributes of the alternatives. The paper concludes with an evaluation of the model and suggestions for its testing and further development.
Cognitive Maps and Spatial Behavior Of Consumers
Authors: MacKay David B. , Olshavsky Richard W. , Sentell Gerald 
Published: September 2010

AbstractTwo multidimensional scaling algorithms are used to externally measure cognitive maps of supermarket locations for a sample of sixty‐one supermarket shoppers. Issues raised in the construction of the cognitive maps are discussed. The relationship between the derived cognitive maps and consumer behavior is compared to the relationship between physical maps and consumer behavior. Behavior is shown to be more closely related to cognitive maps. Differences in cognitive maps are defined and canonically correlated with consumers' socioeconomic and locational attributes. While aggregate cognitive maps are closely associated with physical maps, there is substantial variation between individual maps. This variation is related to shopping behavior and selected socioeconomic and locational characteristics of consumers.
Dimensional Analysis: Some Applications In Human Geography
Authors: Haynes Robin M. 
Published: September 2010

AbstractDimensional analysis is introduced, and applications of it to human geography are considered. Primary and secondary dimensions are selected; techniques of dimensional analysis are used to derive and check a functional relationship drawn from central place theory, to test the dimensional implications of a power function (the Pareto gravity model), to disaggregate a theoretical parameter (the exponential distance decay coefficient), and to simplify a complex system of variables in agricultural location theory to a system of dimensionless products. Difficulties inherent in the application of dimensional analysis to human geography are discussed.
Entropy in Spatial Aggregation
Authors: Batty Michael 
Published: September 2010

AbstractThis paper introduces an approach to the measurement of locational phenomena in a spatial hierarchy using entropy statistics. A number of such statistics suitable for the study of spatial aggregation are derived, and each of these statistics is decomposed at different levels of the spatial hierarchy using principles of decomposition first applied by Theil. These decomposition statistics are compared with the variance analysis applied by Moellering and Tobler and with the spatial entropy measure suggested by Curry. The use of these statistics is then illustrated by data from the Reading subregion and New York City, and the paper is concluded with an analysis of a possible role for entropy and information in problems involving equal‐area zoning.
Fluctuation in the Random Spatial Economy and The Control of Inflation
Authors: Curry Leslie 
Published: September 2010

AbstractA self‐contained spatial economy is set out as the steady‐state of a harmonic oscillator under Gaussian excitation. A dollar bill performs a random walk on a line with elastic barriers at each end and represents payments for traded goods. Diffusive surges of money and the fluctuations in zonal incomes are examined. The center, being less dependent on extra‐zonal trade, has fewer brakes on price levels and can more easily begin “inflation.” Imposing a uniform deflationary policy would cause the periphery to be squeezed without reason while the center would be affected too little and too late. The organization of a futures market in construction is analyzed as a spatially discriminating form of control.
The Effect of Spatial Stimuli on the Estimation of Cognitive Maps
Authors: MacKay David B. 
Published: September 2010

AbstractHand‐drawn and multidimensionally scaled maps of cities in the United States are compared with respect to their congruence with physical maps of the corresponding cities and with respect to subject's evaluations of their similarity to physical maps. The cities chosen are systematically varied to determine the effect of different spatial patterns on the subjects' performance. Hand‐drawn maps are shown to be more like physical maps. Subjects also rate their drawn maps as being more like actual maps than multidimensionally scaled maps. Changes with respect to the spatial pattern of stimuli are apparent.
Some Extensions to Rushton's Spatial Preference Scaling Model
Authors: Girt John L. 
Published: September 2010

AbstractRushton's spatial preference scaling model is extended and its computing algorithm modified in order to utilize more fully all the information contained in the input data set, and to make it a better predictor of choice behavior. The preference scale that is produced by the model measures the certainty with which generalizations can be made about choices between classes of objects. The model offers two significant advantages over commonly used spatial interaction models: freedom from a priori selection of the function relating choice to attributes of objects, and applicability to studies where the number of origin and destination zones is large relative to the populations involved.
The Impact of Telecommuting on the Activity Spaces of Participants
Authors: Saxena Somitra , Mokhtarian Patricia L. 
Published: September 2010

A spatial analysis of the activity spaces of telecommuters, based on the geocoded travel diary data from the State of California Telecommuting Pilot Project, is performed to analyze the impacts of telecommuting. The study analyzes the spatial location, orientation, and extent of the activity locations within the “activity spaces” of telecommuters and a nontelecommuting control group. To be able to quantitatively compare and contrast the travel patterns and the distribution of trip ends within the activity space, several spatial indicators have been defined. Several hypotheses concerning the selection of activity locations by individuals are presented and the impact of telecommuting on the selection of locations for activity is analyzed. Key findings include: on telecommuting days, 86 percent of telecommuters' activities are performed closer to home than to work, compared to 56 percent on normal commuting days; and destinations on telecommuting days are more evenly distributed in all directions around the home, whereas a majority of destinations on commuting days are oriented toward the work location.To be able to understand the influence of the contributing factors toward the selection of nonwork activity locations, potential causal relationships between the influencing factors and the activity location choice are investigated. Several plausible log‐linear model structures for cross‐classified data provide a good fit to these relationships. Key results include: interaction effects of activity location with commute distance and with trip purpose are present in all the best‐fitting models, confirming the importance of these two variables in the selection of activity location; the interaction of activity location and income is also significant; and day status (telecommuting or not) of the employee influences the trip purpose, which in turn affects location.
Aggregation of Sampling Units: An Analytical Solution to Predict Variance
Authors: Bellehumeur Claude , Legendre Pierre 
Published: September 2010

Geographical variables generally show spatially structured patterns corresponding to intrinsic characteristics of the environment. The size of the sampling unit has a critical effect on our perception of phenomena and is closely related to the variance and correlation structure of the data. Geostatistical theory uses analytical relationships for change of support (change of sampling unit size), allowing prediction of the variance and autocorrelation structure that would be observed if a survey was conducted using different sampling unit sizes.To check the geostatistical predictions, we use a test case about tree density in the tropical rain forest of the Pasoh Reserve, Malaysia. This data set contains exhaustive information about individual tree locations, so it allows us to simulate and compare various sampling designs. The original data set was reorganized to compute tree densities for 5 times 5‐, 10 times 10‐, and 20 times 20‐meter quadrat sizes. Based upon the 5 times 5‐meter data set, the spatial structure is modeled using a nugget effect (white noise) plus an exponential model. The change of support relationships, using within‐quadrat variances inferred from the variogram model, predict the spatial autocorrelation structure and new variances corresponding to 10 times 10‐meter and 20 times 20‐meter quadrats. The theoretical and empirical results agreed closely, whereas neglecting the autocorrelation structure would have led to largely underestimating the variance. As the quadrat size increases, the range of autocorrelation increases, while the variance and the proportion of noise in the data decrease.
A Shape Definition for Geographic Applications Based on Edge, Elongation, and Perforation
Authors: Wentz Elizabeth A. 
Published: September 2010

An expanded definition for measuring shape in a geographic context is presented. Shape analysis is important in many geographic contexts such as studying the effects of urban development, measuring geographic characteristics of drainage basins, and examining the patterns of geologic formations.This research implements and tests an approach to expand the current mathematical definition of shape and to measure shape for geographic applications, called the trivariate shape definition. The expanded definition involves identifying three characteristics to define shape: edge, elongation, and perforation. Indices to measure these characteristics were identified and applied to two different data sets. Analysis of results from these data sets suggests that the trivariate index clustered groups of objects based on shape similarity. The trivariate approach provides more flexibility to measure shape by relying on a more specific definition of shape.
Absent and Accounted For: Absenteeism and Cooperative Learning*
Authors: Koppenhaver G. D. 
Published: September 2010

ABSTRACTIn a small section collaborative learning environment where student work teams promote mutual learning about investments, students limit the opportunity to learn from other students if they are absent from class. Absenteeism not only denies the student the opportunity to learn from others but also denies other members of the student's work team the opportunity to learn from the absent student. Other team members' absenteeism should be costly for individual performance if collaborative learning fosters learning and retention. The research finds that while absenteeism is detrimental to the student's own performance, absenteeism of other team members from team activities has a significant negative effect on both individual exam and homework scores. The conclusions validate the benefits of active learning and of encouraging attendance in collaborative learning environments in all disciplines.
Examining Drivers of Course Performance: An Exploratory Examination of an Introductory CIS Applications Course
Authors: Syler Rhonda A. , Cegielski Casey G. , Oswald Sharon L. , Rainer R. Kelly 
Published: September 2010

ABSTRACTThe accelerating diffusion of broadband Internet access provides many opportunities for the development of pedagogically robust Web‐based instruction (WBI). While the supporting technology infrastructure of broadband disseminates, the attention of academic researchers focuses upon issues such as the drivers of student usage of WBI. Specifically, the research presented herein examined the impact of WBI on a student's aggregate course performance. We hypothesized that learning independence (LI) is a determinate factor in a student's use of WBI. In this study, we employed structural equation modeling techniques to examine the data and assess the direct and indirect effects of LI on WBI usage. The subjects, students in an introductory Computer Information Systems applications course, used a Web‐based tutorial program for skills instruction. The findings of this study suggest that WBI usage has a significant impact on a student's course performance. Despite its plausibility, the effect of LI on WBI usage was not significant. However, we did conclude that two of the second order factors of the LI construct have a direct effect on a student's performance in the course.
Seeing Is Believing: The Transitory Influence of Reputation Information on E‐Commerce Trust and Decision Making
Authors: Fuller Mark A. , Serva Mark A. , Benamati John “Skip” 
Published: September 2010

ABSTRACTThis research examines the transitory influence of reputation information on consumer decision making regarding an e‐vendor. Using social judgment theory to explain how reputation information's effect on perceptions may be fleeting, we specifically examined how user trusting beliefs related to an e‐vendor change after a simple exposure to the Web site. A total of 369 college students participated in an experiment that found that reputation information was initially strongly related to trusting beliefs regarding the e‐vendor, but a brief nonpurchase‐related exposure to the e‐vendor's Web site—that is, direct experience—reduced reputation's effects significantly. This research provides insights into why reputation information may be more important in certain circumstances than in others and enhances our understanding of how consumer decision making is affected by different purchasing contexts. This research also has implications on the design and use of trust‐building technologies.
Effect of seed moisture content and d‐limonene on oviposition decisions of the seed beetle Callosobruchus maculatus
Authors: Hudaib Taghread , Hayes William , Brown Sarah , Eady Paul E. 
Published: September 2010

Abstract Callosobruchus maculatus (Fabricius) (Coleoptera: Bruchidae) is a cosmopolitan pest of stored pulses and legumes. Under legume storage conditions neither adults nor larvae drink, with larvae obtaining their hydration from metabolic water. However, lack of water limits female fecundity and longevity, thus females might be expected to preferentially oviposit on seeds with high moisture content so as to minimize water stress on their offspring. This was tested by offering females a choice of seeds that differed in relation to their level of water content. After controlling for differences in seed size, females were found to preferentially oviposit on the driest seeds. Offspring size and larval survival were equivalent on seeds that differed in moisture content, which in combination with the preference to lay on the driest seeds would indicate that the egg laying decisions of C. maculatus females do not function to minimize larval water stress. Analysis of the chemical volatiles released by seeds that differed in their moisture content revealed a greater level of d‐limonene in the environment surrounding high moisture seeds. d‐limonene has known anti‐herbivory properties, thus we suggest the observed female preference for dry seeds may be related to the observed difference in the level of d‐limonene in the immediate vicinity of beans that differ with respect to their moisture content.