Showing papers by "Boston College published in 1994"
Posted Content•
TL;DR: In this paper, the authors evaluate alternative models for detecting earnings management by comparing the specification and power of commonly used test statistics across the measures of discretionary accruals generated by each model.
Abstract: This paper evaluates alternative models for detecting earnings management. The paper restricts itself to models that assume the construct being managed is discretionary accruals, since such models are commonly used in the extant accounting literature. Existing models range from simple models in which discretionary accruals are measured as total accruals, to more sophisticated models that separate total accruals into a discretionary and a non-discretionary component. Prior to this paper, there had been no systematic evidence bearing on the relative performance of these alternative models at detecting earnings management. This paper evaluates the relative performance of the competing models by comparing the specification and power of commonly used test statistics across the measures of discretionary accruals generated by each model. The specification of the test statistics is evaluated by examining the frequency with which they generate type I errors for a random sample of firm-years and for samples of firm-years with extreme financial performance. We focus on samples with extreme financial performance because the stimuli investigated in previous research are frequently correlated with financial performance. The first sample of firms are targeted by the Securities and Exchange Commission for allegedly overstating annual earnings and the second sample is created by artificially introducing earnings management into a random sample of firms.
6,217 citations
TL;DR: In this paper, the authors hypothesize that institutions invest more heavily in companies with strong corporate social performance and find that there is a significant, positive relationship between social percolation and profits.
Abstract: In this study, we hypothesize that institutions invest more heavily in companies with strong corporate social performance. Analysis indicated a significant, positive relationship between social per...
1,096 citations
TL;DR: A review of the American literature in social science for the period 1975-1992 on the determinants of volunteer participation in programs and associations can be found in this article. But most studies are t...
Abstract: This article reviews the American literature in social science for the period 1975–1992 on the determinants of volunteer participation in programs and associations. It finds that most studies are t...
696 citations
Book•
03 May 1994TL;DR: This book discusses words and languages automata and regular languages semigroups and homomorphisms, formal languages and formal logic, regular languages and circuit complexity, and proof of the Krohn-Rhodes theorem proofs of the category theorems.
Abstract: Part 1 Mathematical preliminaries: words and languages automata and regular languages semigroups and homomorphisms. Part 2 Formal languages and formal logic: examples definitions. Part 3 Finite automata: monadic second-order sentences and regular languages regular numerical predicates infinite words and decidable theories. Part 4 Model-theoretic games: the Ehrenfeucht-Fraisse game application to FO [decreasing] application to FO [+1]. Part 5 Finite semigroups: the syntactic monoid calculation of the syntactic monoid application to FO [decreasing] semidirect products categories and path conditions pseudovarieties. Part 6 First-order logic: characterization of FO [decreasing] a hierarchy in FO [decreasing] another characterization of FO [+1] sentences with regular numerical predicates. Part 7 Modular quantifiers: definition and examples languages in (FO + MOD(P))[decreasing] languages in (FO + MOD)[+1] languages in (FO + MOD)[Reg] summary. Part 8 Circuit complexity: examples of circuits circuits and circuit complexity classes lower bounds. Part 9 Regular languages and circuit complexity: regular languages in NC1 formulas with arbitrary numerical predicates regular languages and non-regular numerical predicates special cases of the central conjecture. Appendices: proof of the Krohn-Rhodes theorem proofs of the category theorems.
472 citations
TL;DR: In this article, a study of CME occurrence rates over more than a complete 11-year solar sunspot cycle and a comparison of these rates with those of other activity related to CMEs and with the solar wind particle flux at 1 AU is presented.
Abstract: Coronal mass ejections (CMEs) are an important aspect of coronal physics and a potentially significant contributor to perturbations of the solar wind, such as its mass flux. Sufficient data on CMEs are now available to permit study of their longer-term occurrency patterns. Here we present the results of a study of CME occurrence rates over more than a complete 11-year solar sunspot cycle and a comparison of these rates with those of other activity related to CMEs and with the solar wind particle flux at 1 AU. The study includes an evaluation of correlations to the CME rates, which include instrument duty cycles, visibility functions, mass detection thresholds, and geometrical considerations. The main results are as follows: (1) The frequency of occurrence of CMEs tends to track the solar activity cycle in both amplitude and phase; (2) the CME rates from different instruments, when corrected for both duty cycles and visibility functions, are reasonably consistent; (3) considering only longer-term averages, no one class of solar activity is better correlated with CME rate than any other; (4) the ratio of the annualized CME to solar wind mass flux tends to track the solar cycle; and (5) near solar maximum, CMEs can provide a significant fraction (i.e., approximately equals 15%) of the average mass flux to the near-ecliptic solar wind.
393 citations
TL;DR: A theory of semantic values as a unit of exchange that facilitates semantic interoperability betweeen heterogeneous information systems is provided and it is shown how semantic values can either be stored explicitly or be defined by environments.
Abstract: Large organizations need to exchange information among many separately developed systems. In order for this exchange to be useful, the individual systems must agree on the meaning of their exchanged data. That is, the organization must ensure semantic interoperability. This paper provides a theory of semantic values as a unit of exchange that facilitates semantic interoperability betweeen heterogeneous information systems. We show how semantic values can either be stored explicitly or be defined by environments. A system architecture is presented that allows autonomous components to share semantic values. The key component in this architecture is called the context mediator, whose job is to identify and construct the semantic values being sent, to determine when the exchange is meaningful, and to convert the semantic values to the form required by the receiver.Our theory is then applied to the relational model. We provide an interpretation of standard SQL queries in which context conversions and manipulations are transparent to the user. We also introduce an extension of SQL, called Context-SQL (C-SQL), in which the context of a semantic value can be explicitly accessed and updated. Finally, we describe the implementation of a prototype context mediator for a relational C-SQL system.
371 citations
TL;DR: This article found that men are a bit more active in politics than women and that women are disadvantaged when it comes to the resources that facilitate political activity, when these resource deficits are viewed in the context of the paths to participation taken by men and women.
Abstract: In this investigation of the voluntary participation of men and women, we find that even when the definition of activity is broadened beyond the electoral forms of activity usually considered, men are a bit more active in politics than women. However, the pattern across activities does not conform to the expectations generated by the literature. In comparison with men, women are disadvantaged when it comes to the resources that facilitate political activity. When these resource deficits are viewed in the context of the paths to participation taken by men and women, it turns out that if women were as well endowed with political resources as men, their overall levels of political activity would be closer to men's and their financial contributions would be considerably closer to men's.
347 citations
Journal Article•
TL;DR: Physical and psychosocial benefits from a modest walking exercise program and a support group are possible for patients receiving adjuvant chemotherapy.
Abstract: Purpose/objectives To examine the effects of a comprehensive rehabilitation program on facilitating physical and psychosocial adaptation of women with breast cancer who are receiving adjuvant chemotherapy. Design Experimental. Setting Breast evaluation clinics of two New England medical centers with comprehensive cancer treatment programs. Sample 14 women (mean age = 44 years) receiving adjuvant chemotherapy for breast cancer (86% stage II) following surgical treatment. Methods Subjects were assigned randomly to the experimental group or the usual care group. Experimental group members began a structured exercise program of walking and attended support group meetings. All subjects were tested before beginning chemotherapy, during the course of chemotherapy, and one month following chemotherapy completion. Main research variables Performance status, physical functioning, psychosocial adjustment, self-concept and body image, and 12 symptoms (e.g., fatigue, nausea, anxiety). Findings Measures of physical performance, psychosocial adjustment, and symptom intensity revealed improved adaptation in subjects who completed the walking/support group program. Conclusions Physical and psychosocial benefits from a modest walking exercise program and a support group are possible for patients receiving adjuvant chemotherapy. Implications for nursing practice Although more detailed research is necessary to answer some of the questions raised by this study, implementing the walking program and forming a support group are achievable in an outpatient setting.
319 citations
TL;DR: In this article, the authors review the diverse literature on the effects of product warnings and conclude that warnings inform rather than persuade consumers and consumers selectively attend to warning messages, and that consumers selectively ignore warning messages.
Abstract: The authors review the diverse literature on the effects of product warnings. They conclude that warnings inform rather than persuade consumers and consumers selectively attend to warning messages....
239 citations
TL;DR: In this article, the authors investigated the relationship between supplier concentration and competition in the market for audit services and found that concentration is negatively associated with fees, suggesting that high levels of concentration are related to higher levels of price competition (i.e., lower fees).
Abstract: . This article investigates the relationship between supplier concentration and competition in the market for audit services. The study is motivated by the concern that high levels of concentration may be detrimental, resulting in lower levels of competition, which could harm clients through higher fees and lower levels of service. However, a counterargument is that high levels of concentration may not be detrimental but may result because market leaders display exceptional performance, providing lower-priced audits (perhaps due to economies of scale) and/or enhanced service to clients. We obtained audit fee and financial data on 140 life and health insurance companies and 101 property and casualty insurance companies. Our findings indicate that concentration is negatively associated with fees, suggesting that higher levels of concentration are related to higher levels of price competition (i.e., lower fees). Additionally, we address the validity of concentration as a surrogate for competition by examining competition among the market leaders. Our analysis examines the fees paid by 47 insurance companies that switched auditors during the sample period. We investigate the effect of industry specialization on fees paid by clients that switch auditors, finding evidence of significant fee cutting among market leaders for each others' clients but no evidence of fee reductions for clients switching from nonleaders to market leaders. This is consistent with the claim that there is significant price competition for clients among the market leaders, suggesting that high concentration need not result in low levels of price competition (i.e., higher fees).
Resume. Les auteurs analysent la relation entre la concentration des fournisseurs et la coocurrence sur le marche des services de verification. L'etude decoule de la preoccupation suivant laquelle des niveaux eleves de concentration pourraient etre prejudiciables et donner lieu a une intensite plus faible de la concurrence qui risquerait de leser les clients, en augmentant les honoraires et en diminuant la qualite du service. L'argumentation opposee veut qu'un degre eleve de concentration ne soit pas prejudiciable et puisse etre attribuable au fait que les chefs de file du marche affichent une performance exceptionnelle, offrant des services de verification a meilleur prix (peut-etre en raison d'economies d'echelle) et (ou) mettent l'accent sur le service a la clientele. Les auteurs ont recueilli des donnees relatives aux honoraires de verification et des donnees financieres provenant de 140 societes d'assurances vie et maladie et 101 societes d'assurances I.A.R.D. (incendie, accidents et risques divers). Les resultats de leurs recherches indiquent que la concentration est en relation negative avec les honoraires, ce qui donne a penser que des niveaux plus eleves de concentration sont relies a des niveaux plus eleves de concurrence relative au prix (c'est-a-dire a des honoraires inferieurs). Les auteurs se sont egalement penches sur la validite de la concentration a titre de substitut a la concurrence en examinant la concurrence que se livraient les chefs de file sur le marche. Ils ont analyse les honoraires verses par 47 societes d'assurance qui ont change de verificateurs au cours de la periode analysee. Us ont etudie l'incidence de la specialisation sectorielle sur les honoraires verses par les clients qui changent de verificateurs; les resultats de l'etude demontrent que les cabinets chefs de file reduisent leurs honoraires de facon appreciable a l'intention des clients de leurs concurrents appartenant au groupe des chefs de file; ces resultats ne permettent cependant pas de conclure a des reductions d'honoraires pour les clients qui passent de verificateurs n'appartenant pas aux chefs de file a des verificateurs chefs de file sur le marche. Ces constatations sont conformes a l'hypothese selon laquelle les chefs de file sur le marche se livrent une âpre concurrence relative au prix pour attirer la clientele, ce qui laisse croire que la concentration elevee ne donne pas necessairement lieu a une faible intensite de la concurrence relative au prix (c'est-a-dire a des honoraires superieurs).
237 citations
TL;DR: In this paper, the authors present a general equilibrium monetary model in which inflation distorts a variety of marginal decisions and show that individually none of the distortions is very large, they combine to yield substantial welfare cost estimates.
Abstract: This paper presents a general equilibrium monetary model in which inflation distorts a variety of marginal decisions. Although individually none of the distortions is very large, they combine to yield substantial welfare cost estimates. A sustained 4% inflation like that experienced in the U.S. since 1983 costs the economy the equivalent of 0.41% of output per year when currency is identified as the relevant definition of money and over 1% of output per year when M1 is defined as money. The results illustrate how the traditional, partial equilibrium approach can seriously underestimate the true cost of inflation.
Posted Content•
TL;DR: An examination of the executive compensation structure of 153 randomly-selected manufacturing firms in 1979-1980 provides evidence supporting advocates of incentive compensation, and also suggests that the form rather than the level of compensation is what motivates managers to increase firm value as discussed by the authors.
Abstract: An examination of the executive compensation structure of 153 randomly-selected manufacturing firms in 1979-1980 provides evidence supporting advocates of incentive compensation, and also suggests that the form rather than the level of compensation is what motivates managers to increase firm value Firm performance is positively related to the percentage of equity held by managers and to the percentage of their compensation that is equity-based. Moreover, equity-based compensation is used more extensively in forms with more outside directors. Finally, firms in which a higher percentage of the shares are held by insiders or outside blockholders use less equity-based compensation.
TL;DR: Stable ten-component sandwich compounds have been characterized in which four lithium ions reside between two tetraanions derived from corannulene or its alkyl-substituted derivatives and four additional lithium ions decorate the exterior.
Abstract: Stable ten-component sandwich compounds have been characterized in which four lithium ions reside between two tetraanions derived from corannulene or its alkyl-substituted derivatives and four additional lithium ions decorate the exterior. In tetrahydrofuran solution, the four lithium ions inside the sandwich can exchange environments with the four external lithium atoms, but the two tetraanion decks of the sandwich never separate from one another on the time scale of nuclear magnetic resonance. Theoretical calculations point to a "stacked bowl" conformation and a low energy barrier for synchronous double inversion of the tetraanion bowls in the solvated sandwich compounds.
TL;DR: The authors examined the role of accounting in ideological conflict by examining the ideological role accounting and social disclosure played in the South African divestment debates in the United States during the 1970s and 1980s.
Abstract: Social critiques of accounting have challenged the conventional view of corporate social disclosure as a neutral, technical tool for enhancing corporate social responsibility, and stressed the ideological role accounting plays in legitimating corporate activities. This paper extends the literature on the role of accounting in ideological conflict by examining the ideological role accounting and social disclosure played in the South African divestment debates in the United States during the 1970s and 1980s. The history of the Sullivan Principles and institutional divestment from South Africa provides an empirical context for examining both the potential and limits of accounting's capacity to serve the interests of subordinate groups and social movements.
TL;DR: In this article, the development of interactive problem solving as an unofficial approach to the resolution of international conflicts, especially as we have applied it to the Israeli-Palestinian conflict, is reviewed.
Abstract: This article reviews the development of interactive problem solving as an unofficial approach to the resolution of international conflicts, especially as we have applied it to the Israeli-Palestinian conflict. The article describes the concept of the continuing workshop, which represents our latest attempt to maximize the political impact of interactive problem solving. After presenting the goals, terms of reference, and ground rules of such workshops, the paper examines their potential contribution to the larger process of conflict resolution. The principles of the continuing workshop have been applied in a series of meetings between high-ranking Israeli and Palestinian participants. The paper discusses some of the practical issues confronted in this effort, such as preparation, selection of participants, and the third-party role; and assesses the contribution of this continuing workshop to transforming the relationship between the two societies in conflict.
TL;DR: This article examined differences in stock price reactions following voluntary capital injections by commercial banks and involuntary capital injections required to meet regulatory capital requirements, and found that stock price declines associated with voluntary common stock issues are significantly greater than those associated with involuntary common stock injections, consistent with Ross (1977).
TL;DR: In this article, the authors explore the third-order change in organizations, which refers to attempts to help organizational members to transcend their shared schemata, using the example of Teresa of Avila, a Spanish woman from the sixteenth century whose life was reflected in her organizing activities.
Abstract: Third‐order change in organizations refers to attempts to help organizational members to transcend their shared schemata. It has not previously been explored in depth. Uses mystical experience as a model of how the third‐order change process may occur. Discusses several characteristics of mystical experience, focusing in particular on the central characteristic of transconceptual understanding. Presents an example of Teresa of Avila, a Spanish woman from the sixteenth century whose mystical life was reflected in her organizing activities. Suggests how mystical experience can inform understanding of the third‐order organizational change process and presents a preliminary model of ways in which the third‐order change capacity might be developed.
TL;DR: Observations suggest that early during retinal development, shortly after optic cup formation, there is considerable mixing of progenitor cells.
TL;DR: In this paper, the authors report on an in-depth interview investigation of 2O persons who have been diagnosed and treated for unipolar depression, focusing on the major benchmarks in this career process.
Abstract: This article reports on an in-depth interview investigation of 2O persons who have been diagnosed and treated for unipolar depression. The article proceeds from the observation that although a great deal of survey research has been directed at trying to understand the causes for depression, very little writing has explored the subjective experience of depression. The depression experience is conceived as a moving perspective or career through which persons try to make sense of their inherently ambiguous life condition. Analysis focuses on the major benchmarks in this career process. The key points in the career process are (a) having inchoate feelings of distress, (b) coming to feel that something is "really wrong," (c) having a crisis, (d) coming to grips with an illness identity, and sometimes (e) defining depression as a condition one can get past. Each of these stages corresponds to transformations in persons' self-conceptions.
TL;DR: Fos immunocytochemistry is used to show that the medial preoptic area and ventral bed nucleus of the stria terminalis are activated in maternally behaving female rats and functional modifications in the medial amygdala were related to the changes in Fos expression observed.
Abstract: This study uses Fos immunocytochemistry to show that the medial preoptic area and ventral bed nucleus of the stria terminalis are activated in maternally behaving female rats. In Experiment 1, virgin female rats that showed maternal behavior toward pups had more cells in these regions that expressed Fos-like immunoreactivity than did virgin females that were not maternally responsive. In Experiment 2, postpartum rats that were exposed to pups and showed maternal behavior had more Fos-labeled cells in these regions than did postpartum rats exposed to candy. Evidence also indicated that functional modifications in the medial amygdala were related to the changes in Fos expression observed in the preoptic area and ventral bed nucleus of the stria terminalis.
TL;DR: In this paper, the authors examined the morphological dependence of the presence, orientation, and motion of stable sun-aligned polar cap arcs upon the vector interplanetary magnetic field (IMF).
Abstract: This is the first analysis, using a statistically significant data set, of the morphological dependence of the presence, orientation, and motion of stable sun-aligned polar cap arcs upon the vector interplanetary magnetic field (IMF). For the one winter season analyzed we had 1392 all-sky 630.0-nm images of 2-min resolution containing a total of 150 polar cap arcs, all with corresponding values of the IMF as measured by International Monitoring Platform (IMP) 8 or International Sun Earth Explorer (ISEE) 2. After demonstrating an unbiased data set with smooth normal distributions of events versus the dimensions of time, space, and IMF component, we examine IMF dependencies of the properties of the optical arcs. A well-defined dependence for B(sub z) is found for the presence/absence of stable Sun-aligned polar cap arcs. Consistent with previous statistical studies, the probability of observing polar cap aurora steadily increases for larger positive values of B(sub z), and linearly decreases when B(sub z) becomes more negative. The probability of observing Sun-aligned arcs within the polar cap is determined to vary sharply as a function of the arc location; arcs were observed 40% of the time on the dawnside and only 10% on the duskside. This implies an overall probability of at least 40% for the whole polar cap. 20% of the arcs were observed during 'southward IMF conditions,' but in fact under closer inspection were found to have been formed under northward IMF conditions; these 'residual' positive B(sub z) arcs ha d a delayed residence time in the polar cap of about what would be expected after a north to south transition of B(sub z). A firm dependence on B(sub y) is also found for both the orientation and the dawn-dusk direction of motion of the arcs. All the arcs are Sun-aligned to a first approximation, but present deviations from this orientation, depending primarily upon the location of the arc in corrected geomagnetic (CG) coordinates. The arcs populating the 06-12 and the 12-18 quadrants of the CG coordinate system point toward the cusp. The B(sub y) dependency of the arc alignment is consistent with a cusp displacement in local time according to the sign of B(sub y). We found that the arc direction of motion depended both on B(sub y) and the arc location within the polar cap. For a given value of B(sub y) two well-defined regions (or cells) exist. Within each cell the arcs move in the same direction toward the boundary between the cells. The arcs located in the duskside move dawnward; those in the dawnside move duskward. The relative size of these dusk and dawn regions (or cells) are controlled by the magnitude of B(sub y). This persistent dusk-dawn motion fo the polar cap arcs is interpreted in terms of newly open flux tubes entering the polar cap and exerting a displacement of the convective cells and the polar cap arcs that are embedded within them.
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TL;DR: Payment by Results as mentioned in this paper was a 19th century system of accountability in English and Welsh elementary schools, where every pupil was examined annually by an Inspector, the amount of the governmental grant being largely dependent on the answering.
Abstract: Today the public is demanding that it exercise more control over how tax dollars are spent in the educational sphere, with multitudes also canvassing that education become closely aligned to the marketplace's economic forces. In this paper I examine an historical precedent for such demands, i.e. the comprehensive 19th century system of accountability, "Payment by Results," which endured in English and Welsh elementary schools from 1862 until 1897. Particular emphasis is focused on the economic market-driven aspect of the system whereby every pupil was examined annually by an Inspector, the amount of the governmental grant being largely dependent on the answering. I argue that this was a narrow, restrictive system of educational accountability though one totally in keeping with the age's pervasive utilitarian belief in laissez-faire. I conclude by observing that this Victorian system might be suggestive to us today when calls for analogous schemes of educational accountability are shrill.
TL;DR: Some of the problems encountered by Maya children in situations of ongoing war and state-sponsored terror are described and the development of one specific response, Creative Workshops for Children, an international, interdisciplinary program organized by mental health workers from Argentina, Guatemala and United States is described.
TL;DR: In this paper, the authors show that the winning record of a university's football team is positively related to the number of applications for admittance received by that university, and that an increase in winning percentage by 0.250 tends to produce a 1.3% increase in applicants in the following year.
TL;DR: This article reviews work that shows that the medial preoptic area of the hypothalamus plays a crucial role in controlling the occurrence of maternal behavior in rats, examining its critical inputs and outputs.
Abstract: This article reviews work that shows that the medial preoptic area of the hypothalamus plays a crucial role in controlling the occurrence of maternal behavior in rats. A primary goal of this report is to fit the medial preoptic area into a larger neural circuitry, examining its critical inputs and outputs. Lesions of the medial preoptic area disrupt maternal behavior and estradiol and prolactin injections into this region activate maternal behavior. The medial amygdala, which is located in the limbic telencephalon, sends a neural projection to the preoptic region. Research indicates that this projection influences maternal behavior by relaying olfactory input to the medial preoptic area. The output of the preoptic area influences maternal behavior through descending projections to the brain stem. One of the influences of such projections might be to regulate neural circuits involved in controlling specific maternal responses, such as retrieval (carrying of pups) behavior.
TL;DR: The most widely touted policy alternative is a national system of examinations which would employ "authentic" assessment techniques as discussed by the authors, which do not require students to select their answers from given alternatives; rather, students construct answers, perform, or produce something for evaluation.
Abstract: American testing is in tumult. Traditional, standardized, norm-referenced, multiple choice tests—the policy choice for the past 70 years—are under attack. The most widely touted policy alternative is a national system of examinations which would employ “authentic” assessment techniques. These techniques do not require students to select their answers from given alternatives; rather they require students to construct answers, perform, or produce something for evaluation. Authentic assessments, it is asserted, are worth teaching to; defeat negative test preparation effects associated with multiple choice tests; give teachers clear models of acceptable outcomes; have a positive influence on instruction and learning; measure higher order skills; and lay bare examinees’ thinking processes. Proponents of a national examination system argue that such a system will motivate unmotivated students; all students will meet “world class” standards; our nation’s productivity will be increased, and our global competitiveness restored; and, most importantly from the point of view of this chapter, the assessments will not be unfair to individuals or groups, and will help to improve the academic performance of all students, regardless of race, native language, culture, or gender.2
TL;DR: In this paper, the authors explored the concept of top management team (TMT) certainty, that is, the degree of confidence that the TMT has about its environment assessments and subsequent strategic decisions.
TL;DR: In this article, the authors delineate the differences in assumptions between the two sets of papers, and under their assumptions present an intuitive proof of the Pareto inefficiency of market equilibrium with moral hazard.
TL;DR: This model is consistent with structure-activity relationships of agonists and antagonists that interact with the receptor, and provides a basis to suggest testable molecular mechanisms for changes in the D2 conformational states for high- and low-affinity binding and signal transduction.
Abstract: We present the first model of dopamine D2 receptor transmembrane helices constructed directly from the bacteriorhodopsin (bR) coordinates derived from two-dimensional electron diffraction experiments. We have tested this model by its ability to accommodate rigid agonist and semirigid antagonist molecules which were docked into the putative binding pocket with stabilizing interactions. The model is consistent with structure-activity relationships of agonists and antagonists that interact with the receptor. It also illuminates data on a Na+ site for regulation of receptor function. The plausibility of the model is increased by its consistency with many mutagenesis studies on G protein-coupled receptors. Further, this model provides a basis to suggest testable molecular mechanisms for changes in the D2 conformational states for high- and low-affinity binding and signal transduction. Changes in the conformational state of the receptor are hypothesized to be due partly to movement of helix 7. In contrast to the model presented here, other published models were built using ideal helical structures or following the sense of the bacteriorhodopsin structure rather than the actual available coordinates. The presented model for the dopamine G protein-coupled receptor can be reconciled with the recent rhodopsin projection structure (Schertler, G. F. X.; Villa, C.; Henderson, R. Projection Structure of Rhodopsin.