bluuebunny/crossref_metadata_2025 huggingface dataset:
Strategic Intrafirm Innovation Adoption and Diffusion
Authors: Jensen Richard A.
Published: July 2021

A theory of oligopolistic innovation adoption is developed in which intrafirm diffusions occur because the marginal cost of adoption is increasing in the rate of adoption. The equilibrium intrafirm diffusion curve is S‐shaped or concave, as are empirically observed ones. This diffusion curve is more likely to be S‐shaped the more competitive the industry, the larger the marginal cost of adoption or the pre‐innovation unit cost of production, or the smaller the demand. The diffusion is longer, and so the extent of adoption at any date is lower the more competitive the industry, the larger the marginal cost of adoption or the pre‐innovation unit cost of production, or the smaller the demand. A surprising result is that an increase in the unit cost reduction from the innovation has an ambiguous effect on diffusion. Obviously, a larger cost reduction allows each firm to earn a larger flow profit at every date from the same rate of adoption. However, a more subtle effect is that it also allows the firm to earn the same flow of profit with a slower rate of adoption, and so lower adoption costs. That is, the firms also have an incentive to spread out the diffusion over a longer period of time to save on adoption costs.
Fifteen Theses on Classroom Teaching
Authors: Elzinga Kenneth G.
Published: July 2021

The Southern Economic Association initiated a lecture series on teaching to be presented at its annual meeting. This paper, given on November 24, 2000, was the first such lecture. The editor invited the author to publish the lecture in Southern Economic Journal. Portions of the paper are the fruits of the author's more than 30 years of experience teaching economics. Parts of the paper are based on writings regarding pedagogy outside the discipline of economics. The paper puts forward 15 theses about teaching economics in the classroom. The theses range from propositions about why economics is a particularly difficult subject to teach to suggestions about how the classroom teaching of economics can be improved.
Do Several Winning Coalitions Exist in a State for Senators of the Same Party? Evidence from an Event Study
Authors: McGarrity Joseph P. , Picou Armand
Published: July 2021

We argue that U.S. senators from the same state and in the same party form different winning coalitions. We also develop a theory that stipulates that parties encourage these senators to form very distinct constituency coalitions. Parties use committee assignments as a carrot to give these senators an incentive to represent different groups. In our empirical analysis, we find that there are fewer overlapping committee assignments among senators in the same state when they are from the same party. We also consider the case of John Heinz and Arlen Specter, both Pennsylvania Republicans. When John Heinz died in a plane crash, Political Action Committees (PACs) that bought influence from Specter but not Heinz now had the possibility that the new senator replacing Heinz would include them in his resource constituency. The resulting competition by the new Pennsylvania senator and Specter for campaign resources would lower the price these firms had to pay for representation, thus improving their expected future earnings.
The Differential Effects of Output Shocks on Unemployment Rates by Race and Gender
Authors: Ewing Bradley T. , Levernier William , Malik Farooq
Published: July 2021

This article employs a recently developed time‐series econometric technique to examine the magnitude and persistence of unanticipated changes in real output on unemployment rates by race and gender. Through the use of generalized impulse response analysis, we measure the extent to which the behavior of unemployment rates of white males, black males, black females, and white females differ in response to real output shocks. The results suggest that, while real output growth reduces the unemployment rate of all demographic groups, the effect is larger and more persistent for blacks than whites and for males than for females. The findings are particularly important for understanding the demographic impacts of policy initiatives aimed at inducing changes in real output growth.
Output Effects of Disinflation with Staggered Price Setting
Authors: Carlson John A.
Published: July 2021

A discrete‐time model with staggered price setting is shown to be flexible enough to analyze a variety of scenarios in which policymakers may introduce disinflation. While a recession need not necessarily occur, a semicredible disinflation (i.e., when price setters believe a new lower money growth rate will continue but do not act on future reductions) unambiguously depresses output with staggered prices, no matter how rapidly or slowly the disinflation is introduced.
Exclusive Dealing through Resellers in Auctions with Stochastic Bidder Participation
Authors: Bose Subir , Deltas George
Published: July 2021

This paper demonstrates that a seller prefers to exclude final consumers from an auction and sell only to resellers when these resellers can gain access, at a cost, to a sufficiently bigger market than the seller himself. The intuition is that resellers recoup their expenses for marketing the item by reselling it to final consumers. If some consumers participate in the first auction and are outbid by the resellers, then their values for the item are relatively low. Outbidding part of their customer base is “bad news” for the resellers, and this depresses their bids when consumers compete with them. The socially optimal and revenue‐maximizing choices of auction format may not coincide: Restricting participation of consumers may be socially optimal but privately suboptimal and vice‐versa. The results suggest that (i) the exclusion of final consumers in some auctions may not be driven by transaction cost considerations, and (ii) sellers should not necessarily sell directly to consumers, even though new technologies allow them to do so at essentially zero cost, unless they can access a sufficiently large portion of the market.
Tailored Regulation: Will Voluntary Site‐Specific Environmental Performance Standards Improve Welfare?
Authors: Blackman Allen , Boyd James
Published: July 2021

Increasingly popular tailored regulation (TR) initiatives like the Environmental Protection Agency's Project XL allow industrial facilities to voluntarily substitute site‐specific environmental performance standards for inefficient command‐and‐control regulations. TR can significantly reduce participants' costs of complying with environmental regulations, but in doing so it can also give these participants a competitive advantage. Here we develop an analytical model to show that TR can have adverse welfare effects when if enables relatively inefficient firms in oligopolistic markets to “steal” market share from more efficient firms, and we characterize the regulatory policies that give rise to such outcomes. We also show that regulators' efforts to diffuse the benefits of site‐specific agreements among nonparticipating firms dampen incentives to participate in TR.
Using Spreadsheets to Conduct Monte Carlo Experiments for Teaching Introductory Econometrics
Authors: Craft R. Kim
Published: July 2021

The Monte Carlo experiment can be a valuable pedagogical tool for introductory econometrics courses. In the past, however, the practicality of having students perform Monte Carlo simulations was limited because of the high opportunity cost involved in learning to program. This paper argues that spreadsheets offer a means for beginning students to conduct meaningful Monte Carlo experiments at a relatively low opportunity cost and provides instructions on how to do so with Microsoft Excel. Suggestions are offered for using spreadsheet‐based Monte Carlo experiments effectively in teaching basic econometric concepts.
Class Size Effects on Student Achievement in Norway: Patterns and Explanations
Authors: Bonesrønning Hans
Published: July 2021

The causal effect of class size on student performance is investigated using a maximum class size rule of 30 students to generate an instrument for actual class size. The data come from lower secondary schools in Norway, and the initial analysis reveals a small negative class size effect. Further investigations show that the effect varies among student subgroups and that the benefits of smaller classes are larger in schools with a high proportion of students who come from intact families. The second section of the paper uses information about the teachers' grading practices and the students' efforts in class to shed additional light on the revealed patterns of class size effects. Class size effects seem to be conditional on student effort.
A Cointegration Model of Age‐Specific Fertility and Female Labor Supply in the United States
Authors: McNown Robert
Published: July 2021

Cointegration methods suitable for estimation and testing with nonstationary data are applied to U.S. time‐series data on age‐specific fertility rates, female labor force participation rates, women's wages, unemployment rates and educational attainment, and male relative incomes. Likelihood ratio tests indicate the existence of two cointegrating relations that are identified as a fertility equation and a labor supply equation, respectively. Estimated long‐run relations are consistent with economic models of fertility and female labor market behavior, and these results are robust across both age‐groups and several alternative model specifications.
Endogenous Role in Mixed Markets: A Two‐Production‐Period Model
Authors: Matsumura Toshihiro
Published: July 2021

In this paper, I investigate endogenous roles in a mixed duopoly, where private and state‐owned public turns compete, by allowing two production periods. I find that many equilibria exist, including the Coumot‐type equilibrium and one Stackelberg‐type equilibrium where the public firm becomes the follower. However, another Stackelberg‐type equilibrium where the public firm becomes the leader does not exist. If small inventory costs are introduced, the unique equilibrium outcome becomes the Stackelberg type where the public firm is the follower.
Editorial Favoritism in Economics?
Authors: Medoff Marshall H.
Published: July 2021

Are articles by authors with institutional connections or personal ties to the publishing journal's editor(s)/coeditors of lower quality than those authored without such connections? Examination of articles published in six core economics journals in 1990 found that articles authored by those with such connections, especially service on the publishing journal's editorial board, are statistically and numerically of higher quality than articles by those without such connections. In addition, this quality difference does not decrease over time.
Lotteries, Litigation, and Education Finance
Authors: Dee Thomas S.
Published: July 2021

In 1993, the state of Georgia instituted a lottery that earmarked new funds for instructional and capital expenditures in public schools. In that same year, Tennessee began court‐ordered education finance reforms that were also designed to promote instructional and capital expenditures. Using district‐level panel data, this study presents empirical evidence on how these disparate policies influenced the patterns of educational revenues by source and expenditures by function. The results suggest that both state policies increased the state aid to the poorest districts and promoted some spending on the targeted functions. However, the results also suggest that these reforms influenced spending in several other functional areas.
Legal Minimum Wages and Employment Duration
Authors: Grossberg Adam J. , Sicilian Paul
Published: July 2021

We estimate the effect of minimum wages on employment duration using event history data from the 1988‐1994 rounds of the National Longitudinal Survey of Youth. Existing literature takes two alternative tracks: Some studies predict reduced turnover due to rents created by minimum wages, others focus on the expected increase in turnover due to reduced job amenities and imperfect information. We find that for men, the net effect of a minimum wage depends on its magnitude relative to the typical wage in the local labor market. We find some evidence that where the minimum wage is low, separation rates for men hired at the minimum wage are reduced. We also find that as the relative value of the minimum wage rises, separation hazards increase. We interpret these findings as evidence that rents may accrue to minimum wage workers, but that the job matching process is undermined when the minimum wage binds.
Spatial Monopoly with Product Differentiation
Authors: Peng Shin‐kun
Published: July 2021

Most theoretical work on the behavior of spatial monopoly focuses on the single‐product case, while, in reality, a firm usually produces (or sells) many differentiated products. In this paper, 1 introduce a new model of spatial monopoly with a multiple‐product firm where the firm chooses both the measure of product varieties and the price of each variety to maximize its profit. I also examine the monopolist's optimal decision and its economic effects on the spatial economy with a fixed and variable market fringe, respectively. For a class of preferences to product differentiation, I find that both the quantities produced and the consumer surpluses vary across three different spatial pricing policies. This finding is in contrast to the literature on a single‐product spatial monopoly where those results are invariant across different pricing policies.
AIDS Home‐ and Community‐Based Waivers: Effects on Use of Services, Expenditures, and Survival
Authors: Anderson Kathryn , Mitchell Jean
Published: July 2021

State Medicaid home‐ and community‐based waiver programs for persons with AIDS (PWAs) were implemented with the expectation that PWAs would use these services in lieu of more expensive hospital‐based care. If so, Medicaid spending per PWA should decline, and program costs fall. We analyze Florida Medicaid claims data for PWAs from December 1995 through December 1997 to determine how participation in the waiver program affects the use of inpatient services, the receipt of antiretroviral combination therapies (available to Medicaid recipients throughout the study period), monthly expenditures, and survival of PWAs. We find that waiver participants are more likely to receive combination therapies but less likely to use hospital‐based care than nonparticipants; white men and sicker patients are more likely to join the waiver program than other eligible PWAs; monthly expenditures for waiver participants are 52% lower than for nonparticipants; and waiver participation does not affect survival.
Can Prior Offers and Arbitration Outcomes Be Used to Predict the Winners of Subsequent Final‐Offer Arbitration Cases?
Authors: Marburger Daniel R. , Burgess Paul L.
Published: July 2021

The purpose of interest arbitration is to encourage bargainers to negotiate their own mutually agreeable settlement. In final‐offer arbitration (FOA), the bargainers exchange final offers. If a settlement is not reached, an independent arbitrator selects one of the final offers as the award. At the beginning of each arbitration period, the only information available to bargainers relating to arbitrator preferences is past outcomes. Given its goal of driving negotiated settlements, an effective FOA process requires bargainers to infer useful information about arbitrator preferences from past outcomes. Using data from major league baseball, this article provides evidence that past FOA decisions are positively correlated with the outcomes of future FOA cases.
Economics and English: Language Growth in Economic Perspective
Authors: Reksulak Michael , Shughart William F. , Tollison Robert D.
Published: July 2021

This article examines systematically the growth of the English language from the year 252 cc through 1985. Using a data set collected from the CD‐ROM version of the second edition of the Oxford English Dictionary, we characterize the time series of new words added to the language, by year, calculate rates of growth and obsolescence, and disaggregate the data by parts of speech. Economic models of language growth over a modern period (1830‐1969) are then estimated. We report evidence that language is a “network” good (the number of new English words is negatively related to population and to gross national product), that additions to the language are retarded by government growth, that the stock of words in use is strongly influenced by foreign trade, and that causality runs from economics to neology but not the reverse. Some suggestive evidence on the relative “efficiency” of English also is presented.
Income Tax Evasion Revisited: The Impact of Interest Rate Yields on Tax‐Free Municipal Bonds
Authors: Cebula Richard J.
Published: July 2021

This study empirically investigates a hypothesis that the degree of aggregate federal personal income tax evasion may be influenced by the interest rate yield on high‐grade municipal bonds. After allowing for the impacts of a variety of factors that typically have been inferred to influence income tax evasion, it is found that the higher the tax‐free interest rate yield on high‐grade municipal bonds relative to the taxable yield on 10‐year Treasury notes, the lower the aggregate degree of federal personal income tax evasion.
Why Are Real Interest Rates Not Equalized Internationally?
Authors: Chung S. Young , Crowder William J.
Published: July 2021

In this study, we specify a set of sufficient parity conditions for real interest rates to be equalized internationally, what we call real interest parity (RIP). Using multivariate unit root tests, which have significantly greater power than univariate alternatives, we demonstrate that these sufficient conditions are not satisfied for five industrialized nations over the period of 1960‐1996. We then examine each parity condition individually to shed some light on the source of the rejection of RIP. Our results suggest that no single violation can explain the failure of RIP in all cases. It does appear, however, that the Fisher relation is the least likely to violate the RIP equilibrium, whereas uncovered interest parity (UIP) appears to be the most commonly violated. This result is consistent with a nonstationary risk premium in the foreign exchange market.
Transnational Terrorism 1968‐2000: Thresholds, Persistence, and Forecasts
Authors: Enders Walter , Sandler Todd
Published: July 2021

This article applies a threshold autoregression (TAR) model to a casualties time series to show that the autoregressive nature of such events depends on the level of terrorism at the time of a shock. Following a shock, persistence of heightened attacks characterizes low‐terrorism regimes, but not high‐terrorism regimes. Similar findings are associated with incidents with deaths, bombings with deaths, and hostage‐taking. In contrast, the assassinations series indicates some persistence even in the high‐terrorism state, whereas the threats/hoaxes series displays persistence in only the high‐terrorism state. For all series studied, the TAR model outperforms a standard autoregressive representation. A forecasting method is engineered based on the TAR estimates and nicely tracks resource‐using events.
Theory versus Application: Does Complexity Crowd Out Evidence?
Authors: Coelho Philip R. P. , McClure James E.
Published: July 2021

Donald F. Gordon hypothesized that mathematical complexity in economics is inversely related to operational ism. Here we (i) operationalize Gordon's hypothesis, (ii) test for the significance of trends in complexity for the American Economic Review, Economic Journal, Journal of Political Economy, and Quarterly Journal of Economics, and (iii) test Gordon's hypothesis hy conducting analyses of the contents of articles from the American Economic Review (AER), as well as the contents of articles citing the AER articles. The results do not refute the hypothesis that complexity crowds out operationalism in economics. Additionally, the presence of significant, positive trends toward complexity suggests that the magnitude of the crowding out is on the rise in these journals.
Supermodularity and Complementarity in Economics: An Elementary Survey
Authors: Amir Rabah
Published: July 2021

The literature on supermodular optimization and games is surveyed from the perspective of potential users in economics. This methodology provides a new approach for comparative statics based only on critical assumptions, and allows a general analysis of games with strategic complementarities. The results are presented in a simplified yet rigourous manner, without reference to lattice theory, for the special case of one‐dimensional parameter and actions sets, with the emphasis being on wide accessibility. Detailed applications are presented for well‐known models of consumer behavior, monopoly pass‐through, Bertrand and Cournot competition, strategic R&D, search, and matching. Wherever appropriate, useful tricks for applications and comparative comments are inserted.
Money Growth, Output Growth, and Inflation: A Reexamination of the Modern Quantity Theory's Linchpin Prediction
Authors: Brumm Harold J.
Published: July 2021

A testable implication of the modern quantity theory of money, when viewed as a theory of inflation, is the joint hypothesis that (i) there is a one‐to‐one positive relationship between inflation and the money stock growth rate, (ii) there is a one‐to‐one negative relationship between inflation and the aggregate output growth rate, and (iii) there are no other determinants of inflation besides the money stock and aggregate output expansion rates. This implication is the theory's linchpin prediction. A recent prior study published in this journal examines cross‐country data and reports that this hypothesis cannot be rejected. The present study reexamines the prior study's data and finds that the joint hypothesis is decisively rejected, an unpleasant finding from a monetarist perspective. The article then goes on to propose an alternative to the prior study's model of the inflation process and reports findings that are, from the perspective of a monetarist, at least mildly pleasant.
A Note on Deficit, Implicit Debt, and Interest Rates
Authors: Wang Zijun
Published: July 2021

This short note revisits the long‐standing issue of the relationship between government borrowings and interest rates using vector autoregression (VAR) models. In particular, we consider the dynamic impacts of both official deficit and implicit debt on the interest rates. Two measures of unfunded Social Security obligations (implicit debt) are examined. The recently developed generalized forecast error variance decompositions, which are invariant to the ordering of variables in VARs, are adopted. We find that temporary shocks to the official deficit do not cause real interest rate changes in the short term but do cause moderate changes in the long term. They have significant impact on nominal interest rates in both short and long horizons. The implicit debt also appears to have some moderate influence on real interest rates at long horizons.
Testing for Latent Factors in Models with Autocorrelation and Heteroskedasticity of Unknown Form
Authors: Gilbert Scott , Zemčík Petr
Published: July 2021

This article considers the problem of testing for latent factors or reduced rank in a broad class of (multivariate linear stationary) time‐series models, wherein model errors have autocorrelation and heteroskedasticity of unknown form. It is easy to motivate these models and methods in the context of finance models, and we illustrate with a familiar macromodel of asset returns, proposed previously by Chen, Roll, and Ross. Unfortunately, previously used tests for reduced rank are not sufficiently robust, so we examine two heteroskedasticity and autocorrelation‐consistent (HAC) methods, a HAC version of Hansen's GMM test and a lesser known but more user‐friendly minimum‐distance or ratio of asymptotic densities (RAD) test. We recommend the RAD test, for which we supply computer code. In application, the tests lend more HAC‐robust support to the hypothesis that multiple factors drive the link between the macroeconomy and the returns on bonds and stocks.
A Classroom Exercise: Voting by Ballots and Feet
Authors: Hewett Roger , Holt Charles A. , Kosmopoulou Georgia , Kymn Christine , Long Cheryl X. , Mousavi Shabnam , Sarangi Sudipta
Published: July 2021

This classroom experiment illustrates the efficiency‐enhancing property of a Tiebout system in which local public goods decisions are determined by a political process. Students are given playing cards that induce diverse preferences for expenditures on alternative public goods and are initially assigned to specific communities. Then those in each community vote on the type and level of public goods provision, which determine the tax cost. After the provision and tax results are announced, students are free to move to a location where the prior results are more consistent with their preferences. This process continues for several rounds, with a new vote taken at each location after moves have been made. The exercise demonstrates that the combination of voting with feet and ballots tends to increase the total net benefit for all communities. The voting on provision levels is structured to facilitate a discussion of the median voter theorem.
Hurricane Fatalities and Hurricane Damages: Are Safer Hurricanes More Damaging?
Authors: Sadowski Nicole Cornell , Sutter Daniel
Published: July 2021

The rising cost of hurricanes and other natural hazards has been a concern to policy makers and insurance industry executives. We offer a heretofore overlooked explanation for rising hurricane damages—the reduction in fatalities from hurricanes. Improved hurricane forecasts, more extensive evacuations, and other improvements make hurricanes less lethal, reducing the full cost of living on hurricane‐prone coasts, and should paradoxically increase damages. We confirm this prediction by analyzing land‐falling hurricanes in the mainland United States between 1940 and 1999. We first estimate a time‐varying measure of hurricane lethality and then show that this measure significantly affects damages in hurricane‐prone coastal areas.
Defining Poverty Lines As a Fraction of Central Tendency
Authors: Muller Christophe
Published: July 2021

We show under lognormality that when the Gini coefficient is stable over time, defining the poverty line as a fraction of a central tendency of the living standard distribution restricts the evolution of the poverty measures to stability. That is. poverty does not change if the Gini coefficient does not change. Moreover, when the Gini coefficient slightly changes, most of the poverty change can be considered a change in inequality. The consequences of using different poverty lines are then analyzed. Thus, important features in studies of poverty change based on these lines may result from methodological choices, rather than from economic mechanisms.
Unraveling the Academic Productivity of Economists: The Opportunity Costs of Teaching and Service
Authors: Taylor Susan Washburn , Fender Blakely Fox , Burke Kimberly Gladden
Published: July 2021

This study investigates the relationships among research productivity, teaching, and service on the basis of individual‐specific information involving approximately 715 academic economists. Responding to an online survey, these economists provided information regarding their teaching and service commitments as well as personal and institutional information. The publication record of each respondent was then obtained from EconLit. Together, these data constitute a rich field for the systematic study of research productivity. Results of a Tobit analysis reveal much about the nature of research productivity, underscoring, for instance, the importance of gender, coauthorship, presentations at conferences, and peers who publish. Among the more important findings from this analysis is that both teaching and service commitments have a significantly negative impact on the research productivity of academic economists. These relations hold across types of academic employer, though to varying degrees. Taken together, the results provide interesting insights into the roles of academic scholars, teachers, and colleagues.
The Spread of Antidumping Regimes and the Role of Retaliation in Filings
Authors: Feinberg Robert M. , Reynolds Kara M.
Published: July 2021

Over the past decade, the worldwide use of antidumping has become very widespread—41 WTO‐member countries initiated antidumping cases over the 1995‐2003 period. From another perspective, U.S. exporters were subjected to 139 antidumping cases during this period, by enforcement agencies representing 20 countries. In this context, it is natural to consider whether antidumping filings may be motivated as retaliation against similar measures imposed on a country's exporters. This is the focus of our study, though we also control for the bilateral export flows involved and nonretaliatory impacts of past cases, with other motivations—macroeconomic, industry‐specific, and political considerations—dealt with through fixed effects. Applying probit analysis to a WTO database on reported filings, we find strong evidence that retaliation was a significant motive in explaining the rise of antidumping filings over the past decade, though interesting differences emerge in the reactions to traditional and new users of antidumping.
Uniform versus Discriminatory Tariffs: When Will Export Taxes Be Used?
Authors: Liao Pei‐Cheng , Wong Kar‐yiu
Published: July 2021

This paper examines the noncooperative interactions between two exporting countries and one importing country when all of them are seeking the optimal policies to improve their welfare. Whereas the importing country has the incentive to impose tariffs on the goods coming from the two exporting countries, the export policies chosen by the exporting countries depend on the tariff regime, whether uniform or discriminatory tariffs are used. It is argued that export taxes are chosen by both exporting countries in some cases, and that whereas the importing country prefers a uniform tariff regime, the exporting countries find a discriminatory tariff regime preferable.
Recent Trends in the Skill Composition of Legal U.S. Immigrants
Authors: Polgreen Linnea , Simpson Nicole B.
Published: July 2021

We examine fluctuations in the predicted educational attainment of newly arrived legal U.S. immigrants between 1972 and 1999 by combining data from the U.S. Immigration and Naturalization Service with the Current Population Survey. A mid‐1980s decline gave way to a noticeable improvement in the skill base of the immigrant population between 1987 and 1993. A short decline in the quality of immigrant skills—less severe than that of the mid‐1980s—took place in the mid‐1990s. In 1998, the trend reverses once more: The labor market quality of new legal U.S. immigrants improves. The primary sources of the fluctuations include changes in the quality and quantity of immigrants obtaining an adjustment and variations in the distribution of source regions and entry class types among new legal U.S. immigrants.
Does Crime Pay? A Classroom Demonstration of Monitoring and Enforcement
Authors: Anderson Lisa R. , Stafford Sarah L.
Published: July 2021

This article presents a classroom game in which students choose whether or not to comply with pollution regulations. By varying the level of monitoring and fines for noncompliance, the game shows students how the probability and severity of enforcement affects incentives for compliance. The game can be adapted for settings other than environmental regulation and can be used in a variety of classes including regulation, law and economics, environmental economics, public economics, or economics of crime classes. It can easily be conducted in a 50‐minute class period.
A Cartel's Response to Cheating: An Empirical Investigation of the De Beers Diamond Empire
Authors: Bergenstock Donna J. , Deily Mary E. , Taylor Larry W.
Published: July 2021

De Beers is one of the longest lived international cartels in history. But have recent events threatened the diamond pricing structure so carefully developed over the past 100 years? In this paper, we use time series econometric techniques to evaluate the cartel's response to Russian cheating in the 1990s, We find that, despite massive Russian leaks, the cartel held to its long‐term supply management policy of using its inventory to control the flow of rough diamonds into downstream markets. Although the cartel was able to survive the cheating, it remains unclear whether De Beers will continue to rely on its traditional strategy.
Academic Pay in the United Kingdom and the United States: The Differential Returns to Productivity and the Lifetime Earnings Gap
Authors: Moore William J. , Newman Robert J. , Terrell Dek
Published: July 2021

This paper estimates earnings functions for two samples of U.K. and U.S. academic economists. Despite significant differences in compensation schemes, a comparably specified human capital earnings model does a good job explaining earnings variations for academic economists in both countries. Our estimates suggest that rewards for research are more immediate and direct in the United States. Because of the national salary scale, the payoffs to experience and seniority are greater and the payoffs to research are lower in the United Kingdom than in the United States. After adjusting for productivity and demographic factors, we find that U.S. economists are paid approximately 40% more than otherwise equivalent economists in the United Kingdom. Simulating career age‐earnings profiles for both markets, we find that the earnings gap widens with experience for relatively productive research economists and may even narrow with age for relatively less productive research economists. Nevertheless, the cumulative lifetime earnings foregone are substantial for research and nonresearch economists in the United Kingdom.
Asymmetric Regulation and Airport Dominance in International Aviation: Evidence from the London‐New York Market
Authors: Bilotkach Volodymyr
Published: July 2021

International airline markets have the rather unusual feature of partial deregulation with asymmetric regulatory constraints: Some carriers face entry restrictions different from others for a given route. Like domestic air travel, international travel also features hubs, where a single carrier may dominate a given airport. This article examines the effects of asymmetric regulation and airport dominance on airlines' fares in the London‐New York market, a market uniquely suited for identifying the effects of both of these issues. Comparison data from the symmetrically regulated Frankfurt‐New York and Paris‐New York markets enable a difference‐in‐differences identification strategy. Regulatory restrictions are found to decrease an affected carrier's fares, whereas airport dominance increases a dominant airline's fares.
Exploring the structure of the GAD‐7 scale in primary care patients with emotional disorders: A network analysis approach
Authors: Moriana Juan A. , Jurado‐González Francisco J. , García‐Torres Francisco , Contreras Alba , Muñoz‐Navarro Roger , González‐Blanch César , Medrano Leonardo A. , Ruiz‐Rodríguez Paloma , Cano‐Vindel Antonio
Published: July 2021

Objective

Anxiety symptoms are one of the most frequent manifestations in people attending primary care, although how the symptoms are associated is unclear. This study aimed to establish the symptom structure of the Generalized Anxiety Disorder scale (GAD‐7) using a novel network approach in combination with traditional analytical tools.

Methods

A sample of 1704 primary care patients with emotional disorders (i.e., anxiety, depression, and/or somatization) completed the GAD‐7 to report their anxiety symptoms. We examined the GAD‐7 structure using exploratory graph analysis (EGA) compared to exploratory factor analysis (EFA) and confirmatory factor analysis.

Results

The EFA results showed a one‐factor solution, but EGA revealed a two‐factor solution (cognitive–emotional and somatic). “Worrying too much” and “difficulty relaxing” were the most relevant symptoms.

Conclusions

The results support the possible distinction between the somatic and cognitive–emotional components of the GAD‐7, thus permitting more specific screening in primary care settings.
Roles of PLCβ, PIP2, and GIRK channels in arginine vasopressin‐elicited excitation of CA1 pyramidal neurons
Authors: Hu Binqi , Boyle Cody A. , Lei Saobo
Published: July 2021

Arginine vasopressin (AVP) is a hormone exerting vasoconstrictive and antidiuretic action in the periphery and serves as a neuromodulator in the brain. Although the hippocampus receives vasopressinergic innervation and AVP has been shown to facilitate the excitability of CA1 pyramidal neurons, the involved ionic and signaling mechanisms have not been determined. Here we found that AVP excited CA1 pyramidal neurons by activation of V1areceptors. Functions of G proteins and phospholipase Cβ (PLCβ) were required for AVP‐elicited excitation of CA1 pyramidal neurons, whereas intracellular Ca2+release and protein kinase C were unnecessary. PLCβ‐mediated depletion of phosphatidylinositol 4,5‐bisphosphate (PIP2) was required for AVP‐elicited excitation of CA1 pyramidal neurons. AVP augmented the input resistance and increased the time constants of CA1 pyramidal neurons. AVP induced an inward current in K+‐containing intracellular solution, whereas no inward currents were observed with Cs+‐containing intracellular solution. AVP‐sensitive currents showed inward rectification with a reversal potential close to the K+reversal potential, suggesting the involvement of inwardly rectifying K+channels. AVP‐induced currents were sensitive to the micromolar concentration of Ba2+and tertiapin‐Q, whereas application of ML 133, a selective Kir2 channel blocker had no effects, suggesting that AVP excited CA1 pyramidal neurons by depressing G protein‐gated inwardly rectifying K+channels. Activation of V1areceptors in the CA1 region facilitated glutamatergic transmission onto subicular pyramidal neurons, suggesting that AVP modulates network activity in the brain. Our results may provide one of the cellular and molecular mechanisms to explain thein vivophysiological functions of AVP.
The ependymal cell cytoskeleton in the normal and injured spinal cord of mice
Authors: Trujillo‐Cenóz Omar , Rehermann María I. , Maciel Cecilia , Falco María V. , Fabbiani Gabriela , Russo Raúl E.
Published: July 2021

The cytoskeleton of ependymal cells is fundamental to organize and maintain the normal architecture of the central canal (CC). However, little is known about the plasticity of cytoskeletal components after spinal cord injury. Here, we focus on the structural organization of the cytoskeleton of ependymal cells in the normal and injured spinal cord of mice (both females and males) using immunohistochemical and electron microscopy techniques. We found that in uninjured animals, the actin cytoskeleton (as revealed by phalloidin staining) was arranged following the typical pattern of polarized epithelial cells with conspicuous actin pools located in the apical domain of ependymal cells. Transmission electron microscopy images showed microvilli tufts, long cilia, and characteristic intercellular membrane specializations. After spinal cord injury, F‐actin rearrangements paralleled by fine structural modifications of the apical domain of ependymal cells were observed. These changes involved disruptions of the apical actin pools as well as fine structural modifications of the microvilli tufts. When comparing the control and injured spinal cords, we also found modifications in the expression of vimentin and glial fibrillary acidic protein (GFAP). After injury, vimentin expression disappeared from the most apical domains of ependymal cells but the number of GFAP‐expressing cells within the CC increased. As in other polarized epithelia, the plastic changes in the cytoskeleton may be critically involved in the reaction of ependymal cells following a traumatic injury of the spinal cord.
Safe prescribing in the digital age – evaluation of a pharmacist‐led prescribing program for intern medical officers
Authors: McCleery Nallini , Forman Ariadne N. , Edmunds Catherine A. , Bullock Brooke L.
Published: July 2021

Improving intern medical officers’ (IMOs’) prescribing skills and self‐confidence, in the age of digital prescribing, presents a modern healthcare challenge. This study evaluated the effectiveness of a pharmacist‐led prescribing program to IMOs during orientation. The interactive program aimed to identify useful clinical prescribing support tools through case‐based learning using the hospitals’ digital prescribing program. The program was delivered to 90 IMOs with 56 matched pre‐ and post‐program questionnaires completed. There was an increase in IMOs’ self‐confidence and ability to apply prescribing knowledge to clinical cases post‐program, and 100% of IMOs agreed that the program should be included in future medical intern orientation programs. Five post‐program interviews highlighted that key learnings were used in clinical practice and knowledge was sustained post‐program. This pharmacist‐led prescribing program for IMOs that introduced clinical decision tools to support safe prescribing using a digital system, resulted in overall improved self‐confidence and prescribing skills.
Can luxury attitudes impact sustainability? The role of desire for unique products, culture, and brand self‐congruence
Authors: Eastman Jacqueline K. , Iyer Rajesh , Dekhili Sihem
Published: July 2021

This study examines the effect of value‐expressive and social‐adjustive luxury attitudes on sustainable behaviors, specifically ecologically conscious consumer behavior, and socially responsible consumer behavior. This study investigates the mediating effect of the desire for unique products on the relationship between value‐expressive and social‐adjustive attitudes and sustainable behaviors. The moderating roles of brand self‐congruence and the cultural values of collectivism and masculinity on these relationships are also explored. The results offer support for the mediating role of the desire for unique products. Furthermore, the connection between the desire for unique products and ecologically conscious consumer behavior (but not socially responsible consumer behavior) is enhanced with the moderating cultural value of collectivism and the connection between the desire for unique products and socially responsible consumer behavior (but not ecologically conscious consumer behavior) is enhanced by the moderating factor of brand self‐congruence. The findings help to explain the conflicting findings regarding luxury and sustainability.
An improvement in drilling of SiCp/glass fiber‐reinforced polymer matrix composites using response surface methodology and multi‐objective particle swarm optimization
Authors: Antil Parvesh , Singh Sarbjit , Manna Alakesh , Katal Nitish , Pruncu Catalin
Published: July 2021

The growing dominance in terms of industrial applications has helped polymer‐based composite materials in conquering new markets relentlessly. But the presence of fibrous residuals and abrasive particles as reinforcement in polymer matrix composites (PMCs) affects the output quality characteristics (OQCs) of microdrilling operations. The OQC aims at reducing overcuts and momentous material removal rate (MRR). In such perception, multi‐objective particle swarm optimization (MOPSO) evident to be a suitable optimization technique for prediction and process selection in manufacturing industries. The present paper focuses on multi‐objective optimization of electrochemical discharge drilling parameters during drilling of SiCp and glass fiber‐reinforced PMCs using MOPSO. The response surface methodology (RSM)‐based central composite design was used for the experiment planning. Electrolyte concentration, interelectrode gap, duty factor, and voltage were used as process parameters, whereas MRR and overcut were observed as OQCs. The obtained experimental results were initially optimized by RSM‐based desirability function and later with multiresponse optimization technique MOPSO to achieve best possible MRR with lower possible overcut. The comparative analysis proves that OQCs can be effectively improved by using MOPSO.
First‐Principles Study on Methane Adsorption Performance of Ti‐Modified Porous Graphene
Authors: Zhao Yingjie , Chen Yuhong , Xu Wenhui , Zhang Meiling , Zhang Cairong
Published: July 2021

Porous graphene (PG) is an important candidate material for energy gas adsorption and storage due to its large specific surface area and low mass. Herein, based on first‐principles density functional theory, the adsorption performances of PG and titanium‐modified porous graphene (Ti‐PG) systems on methane (CH4) molecules are investigated. It is discovered that the optimal adsorption position of a single CH4 molecule on PG is the center C‐ring pore, and the adsorption energy is −0.228 eV. In the Ti‐PG system, the best position for Ti atom modification is the PG center pore, with a binding energy of −3.603 eV. When two Ti atoms modify the PG system, 24 CH4 molecules can be adsorbed on both sides, the adsorption amount of CH4 can reach 54.7 wt%, and the average adsorption energy is −0.207 eV. After the adsorption of CH4 molecules, the electrostatic interaction between the overall electronegative CH4 molecules and the electropositive Ti atom, the electrostatic interaction between the electropositive surface CH4 molecules and the PG substrate, and the van der Waals force due to the polarity of CH4 molecules create synergistic effects, which improve the CH4 adsorption performance of the Ti‐PG system.
Independent Component Analysis for Noise and Artifact Removal in Three-Dimensional Polarized Light Imaging
Authors: Benning Kai , Menzel Miriam , Reuter Jan André , Axer Markus
Published: July 2021

In recent years, Independent Component Analysis (ICA) has successfully been applied to remove noise and artifacts in images obtained from Three-dimensional Polarized Light Imaging (3D-PLI) at the mesoscale (i.e., 64 $$\upmu $$
μ
m). Here, we present an automatic denoising procedure for gray matter regions that allows to apply the ICA also to microscopic images, with reasonable computational effort. Apart from an automatic segmentation of gray matter regions, we applied the denoising procedure to several 3D-PLI images from a rat and a vervet monkey brain section.
New IIB intersecting brane solutions yielding supersymmetric AdS3 vacua
Authors: Balaguer Juan R. , Dibitetto Giuseppe , Fernández-Melgarejo José J.
Published: July 2021

Abstract

We consider different (supersymmetric) brane intersections in type IIB string theory that preserve (1 + 1)D Lorentz symmetry. We provide the full supergravity solutions in their analytic form and discuss their physical properties. The Ansatz for the spacetime dependence of the different brane warp factors goes beyond the harmonic superposition principle. By studying the associated near-horizon geometry, we construct interesting classes of AdS3 vacua in type IIB and highlight their relation to the existing classifications in the literature. Finally, we discuss their holographic properties.