External Diseconomies in Competitive Supply: Comment

In a recent article in this Review, Charles Goetz and James Buchanan (G-B) assert that . . . the standard description of misallocation in the presence of external production diseconomies is misleading . . . because these externalities produce a . . . combination of exchange-inefficiency with production-inefficiency [which ] renders the construction of correction devices much more difficult (p. 889). Stated otherwise their contention is that with external diseconomies that are internal to an industry, i.e., those that each firm in an industry inflicts on other firms in the same industry, a competitive regime in the presence of a per unit tax on output designed to eliminate the difference between private and social marginal cost will not achieve a Pareto optimum. The competitive equilibrium even after the imposition of the corrective tax lies inside the production possibilities frontier. The purpose of this note is to suggest that the G-B analysis while technically correct is based on a set of assumptions that differs in a particular aspect from what we believe to be the assumptions of the neoclassical paradigm. Moreover within the framework of the neoclassical model we show the standard prescription regarding a corrective tax to be correct. As it turns out, the difference between the G-B model and the neoclassical model is likely to be negligible in any meaningful application but in any case we show that in the G-B model, a lump sum tax imposed on top of the standard Pigovian per-unit tax will restore full Pareto optimality

General principles of single-construct chromosomal gene drive

Gene drive systems are genetic elements capable of spreading into a population even if they confer a fitness cost to their host. We consider a class of drive systems consisting of a chromosomally located, linked cluster of genes, the presence of which renders specific classes of offspring arising from specific parental crosses unviable. Under permissive conditions, a number of these elements are capable of distorting the offspring ratio in their favor. We use a population genetic framework to derive conditions under which these elements spread to fixation in a population or induce a population crash. Many of these systems can be engineered using combinations of toxin and antidote genes, analogous to Medea, which consists of a maternal toxin and zygotic antidote. The majority of toxin–antidote drive systems require a critical frequency to be exceeded before they spread into a population. Of particular interest, a Z-linked Medea construct with a recessive antidote is expected to induce an all-male population crash for release frequencies above 50%. We suggest molecular tools that may be used to build these systems, and discuss their relevance to the control of a variety of insect pest species, including mosquito vectors of diseases such as malaria and dengue fever

External Economies and Competitive Equilibrium

In an article published in 1955, Murray Kemp analyzed the case for interference with the competitive allocation of resources when external economies of production are present. In the specific model we are interested in—where the costs of any one producer\u27s operations are affected by the total output of all producers of the same product—Kemp attempted to show that where entry into the industry is closed (although the industry is otherwise perfectly competitive), there can always be found a subsidy, either on the product or on a particular factor, which will be a sufficient incentive to firms to produce an optimal output or to use an optimal quantity of each factor. However Kemp argues that where there is open entry, subsidies are rarely a sufficient remedy for the misallocation of resources resulting from external economies; in many cases found in reality, fiscal controls are impotent to restore an optimal allocation of resources. In the absence of far-reaching changes in the laws safeguarding property rights, the only possible solution [emphasis added] in those cases involves recourse to direct controls. We disagree with this conclusion and intend to show that for the kind of external economy discussed by Kemp, even in the case of open entry a simple Pigovian subsidy is sufficient to restore the economy to a Pareto-optimal position. (A similar conclusion applies to external diseconomies where a tax is the policy variable.

External Diseconomies in Competitive Supply: Comment

In a recent article in this Review, Charles Goetz and James Buchanan (G-B) assert that . . . the standard description of misallocation in the presence of external production diseconomies is misleading . . . because these externalities produce a . . . combination of exchange-inefficiency with production-inefficiency [which ] renders the construction of correction devices much more difficult (p. 889). Stated otherwise their contention is that with external diseconomies that are internal to an industry, i.e., those that each firm in an industry inflicts on other firms in the same industry, a competitive regime in the presence of a per unit tax on output designed to eliminate the difference between private and social marginal cost will not achieve a Pareto optimum. The competitive equilibrium even after the imposition of the corrective tax lies inside the production possibilities frontier. The purpose of this note is to suggest that the G-B analysis while technically correct is based on a set of assumptions that differs in a particular aspect from what we believe to be the assumptions of the neoclassical paradigm. Moreover within the framework of the neoclassical model we show the standard prescription regarding a corrective tax to be correct. As it turns out, the difference between the G-B model and the neoclassical model is likely to be negligible in any meaningful application but in any case we show that in the G-B model, a lump sum tax imposed on top of the standard Pigovian per-unit tax will restore full Pareto optimality

Geographic Market Definition in an International Context

Market definition is generally regarded as a key step in antitrust analysis. Market definition has two components. Product market definition seeks to include all products that are meaningful substitutes. Geographic market definition seeks to incorporate all relevant sources of the product in question. This paper is concerned with geographic market definition and, in particular, how geographic markets are defined in situations where competition may, at least to some extent, transcend national boundaries. The subject of the paper may be of some current interest for two reasons. First, the perception is widespread that, over the past twenty or so years, competition in many products and services has become increasingly international in scope and that this trend will continue. Second, the way in which foreign competition is taken into account in performing the antitrust analysis can have a dramatic impact on the legal or policy conclusions that are reached in a particular instance. The legality of a proposed merger, for example, may turn entirely on how competition from foreign sellers is treated. For antitrust purposes, when we say that competition has become more international in scope, we mean primarily that the range of possible suppliers for many goods and services to U.S. consumers increasingly includes sellers who do not produce or are not primarily headquartered in the United States or that an increasing portion of sales by American-based firms are to customers abroad. Many aspects of antitrust are potentially affected by these changes. Some of the more complex issues involve jurisdictional considerations and these will not be discussed here. As we will see, however, the subject of market definition exposes almost all of the substantive (as opposed to jurisdictional) considerations that come into play when we take account of the international aspect of certain markets. The paper has three main parts. The first focuses on the role market definition plays in antitrust analysis and, in particular, the link between market definition and market power. The second explores the particular issues that are raised with respect to market definition when there is an international aspect to competition. The final section addresses some of the empirical questions raised by the largely theoretical analysis of the first two parts of the paper

Geographic Market Definition in an International Context

Market definition is generally regarded as a key step in antitrust analysis. Market definition has two components. Product market definition seeks to include all products that are meaningful substitutes. Geographic market definition seeks to incorporate all relevant sources of the product in question. This paper is concerned with geographic market definition and, in particular, how geographic markets are defined in situations where competition may, at least to some extent, transcend national boundaries. The subject of the paper may be of some current interest for two reasons. First, the perception is widespread that, over the past twenty or so years, competition in many products and services has become increasingly international in scope and that this trend will continue. Second, the way in which foreign competition is taken into account in performing the antitrust analysis can have a dramatic impact on the legal or policy conclusions that are reached in a particular instance. The legality of a proposed merger, for example, may turn entirely on how competition from foreign sellers is treated. For antitrust purposes, when we say that competition has become more international in scope, we mean primarily that the range of possible suppliers for many goods and services to U.S. consumers increasingly includes sellers who do not produce or are not primarily headquartered in the United States or that an increasing portion of sales by American-based firms are to customers abroad. Many aspects of antitrust are potentially affected by these changes. Some of the more complex issues involve jurisdictional considerations and these will not be discussed here. As we will see, however, the subject of market definition exposes almost all of the substantive (as opposed to jurisdictional) considerations that come into play when we take account of the international aspect of certain markets. The paper has three main parts. The first focuses on the role market definition plays in antitrust analysis and, in particular, the link between market definition and market power. The second explores the particular issues that are raised with respect to market definition when there is an international aspect to competition. The final section addresses some of the empirical questions raised by the largely theoretical analysis of the first two parts of the paper

Downward shortwave surface irradiance from 17 sites for the FIRE/SRB Wisconsin experiment

A field experiment was conducted in Wisconsin during Oct. to Nov. 1986 for purposes of both intensive cirrus cloud measurments and SRB algorithm validation activities. The cirrus cloud measurements were part of the FIRE. Tables are presented which show data from 17 sites in the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment/Surface Radiation Budget (FIRE/SRB) Wisconsin experiment region. A discussion of intercomparison results and calibration inconsistencies is also included

Policy Implementation in Higher Education: The Dynamics of a Fall Break

A case study using mixed methods that critically appraises the implementation of a mental health policy in higher education in the absence of evidence to inform the policy using an exemplar case from one mid-sized post-secondary institution was the motivation for this research. Explanation building was used to iteratively analyse data on rival explanations of the implementation of the fall break policy. Analyses from the surveys revealed that overall, only 36.9 per cent of students perceived an increase in workload before the break and only 29.6 per cent of students perceived an increase in workload after the break. However, the focus groups and professor interviews revealed that the timing of the fall break had an impact on how students and professors experienced the break and their perceptions on its impact on student mental health. If baseline data regarding the implementation of the fall break would have been collected prior to its implementation, we could have possibly avoided the implementation issues that arose. While this research provides an exemplar case of a fall break policy at one post-secondary institution, the policy learning is universal

Confinement of gene drive systems to local populations: A comparative analysis

Mosquito-borne diseases such as malaria and dengue fever pose a major health problem through much of the world. One approach to disease prevention involves the use of selfish genetic elements to drive disease-refractory genes into wild mosquito populations. Recently engineered synthetic drive systems have provided encouragement for this strategy; but at the same time have been greeted with caution over the concern that transgenes may spread into countries and communities without their consent. Consequently, there is also interest in gene drive systems that, while strong enough to bring about local population replacement, are unable to establish themselves beyond a partially isolated release site, at least during the testing phase. Here, we develop simple deterministic and stochastic models to compare the confinement properties of a variety of gene drive systems. Our results highlight several systems with desirable features for confinement—a high migration rate required to become established in neighboring populations, and low-frequency persistence in neighboring populations for moderate migration rates. Single-allele underdominance and single-locus engineered underdominance have the strongest confinement properties, but are difficult to engineer and require a high introduction frequency, respectively. Toxin–antidote systems such as Semele, Merea and two-locus engineered underdominance show promising confinement properties and require lower introduction frequencies. Killer-rescue is self-limiting in time, but is able to disperse to significant levels in neighboring populations. We discuss the significance of these results in the context of a phased release of transgenic mosquitoes, and the need for characterization of local ecology prior to a release

Novel Synthetic Medea Selfish Genetic Elements Drive Population Replacement in Drosophila; a Theoretical Exploration of Medea-Dependent Population Suppression

Insects act as vectors for diseases of plants, animals, and humans. Replacement of wild insect populations with genetically modified individuals unable to transmit disease provides a potentially self-perpetuating method of disease prevention. Population replacement requires a gene drive mechanism in order to spread linked genes mediating disease refractoriness through wild populations. We previously reported the creation of synthetic Medea selfish genetic elements able to drive population replacement in Drosophila. These elements use microRNA-mediated silencing of myd88, a maternally expressed gene required for embryonic dorso-ventral pattern formation, coupled with early zygotic expression of a rescuing transgene, to bring about gene drive. Medea elements that work through additional mechanisms are needed in order to be able to carry out cycles of population replacement and/or remove existing transgenes from the population, using second-generation elements that spread while driving first-generation elements out of the population. Here we report the synthesis and population genetic behavior of two new synthetic Medea elements that drive population replacement through manipulation of signaling pathways involved in cellular blastoderm formation or Notch signaling, demonstrating that in Drosophila Medea elements can be generated through manipulation of diverse signaling pathways. We also describe the mRNA and small RNA changes in ovaries and early embryos associated from Medea-bearing females. Finally, we use modeling to illustrate how Medea elements carrying genes that result in diapause-dependent female lethality could be used to bring about population suppression