Learning is enhanced by tailoring instruction to individual genetic differences.

It is widely argued that personalized instruction based on individual differences in learning styles or genetic predispositions could improve learning outcomes. However, this proposition has resisted clear demonstration in human studies, where it is difficult to control experience and quantify outcomes. Here, we take advantage of the tractable nature of vocal learning in songbirds (Lonchura striata domestica) to test the idea that matching instruction to individual genetic predispositions can enhance learning. We use both cross-fostering and computerized instruction with synthetic songs to demonstrate that matching the tutor song to individual predispositions can improve learning across genetic backgrounds. Moreover, we find that optimizing instruction in this fashion can equalize learning differences across individuals that might otherwise be construed as genetically determined. Our results demonstrate potent, synergistic interactions between experience and genetics in shaping song, and indicate the likely importance of such interactions for other complex learned behaviors

Class Certification and the Substantive Merits

The United States Supreme Court, in its 1974 decision, Eisen v. Carlisle & Jacquelin, held that judges should not conduct a preliminary inquiry into the merits of a suit as part of the decision whether to certify a class. The federal courts have struggled ever since to honor Eisen\u27s bar while still conducting a credible certification analysis-a task complicated by the fact that merits-related factors are often relevant to Rule 23 requirements. The result is a muddled body of case law in which courts tend to certify generously and avoid inquiring into the merits of substantive issues even when those issues are crucial to the certification analysis. This approach creates high social costs by inviting frivolous and weak class action suits. This Article argues that the Eisen rule should be abolished. Trial judges should assess competing evidence, not just allegations, and should evaluate case strength whenever the specific requirements of Rule 23 call for an inquiry into merits-related factors. For example, a party relying on a substantive issue to show commonality or predominance should have to demonstrate a likelihood of success on the issue. The Article also goes further and recommends that judges always conduct a preliminary inquiry into the merits before certifying a class, regardless of whether merits-related factors are directly relevant to a specific requirement of Rule 23. The Article first reviews the history of the Eisen rule and surveys the current state of the law, before turning to a policy analysis of the rule\u27s effects. The policy discussion criticizes the traditional arguments and then offers a systematic evaluation of error and process costs. Error costs must be evaluated in light of the extremely high probability of postcertification settlement. Eisen\u27s liberal approach creates a substantial risk of erroneous certification grants that cannot be corrected later when a case settles. This risk coupled with the high likelihood of settlement invites frivolous and weak class action suits. The result is a serious error-cost problem with regard to certification. At the same time, requiring a merits review at the certification stage increases the risk of erroneous certification denials. But for several reasons this risk is not likely to increase dramatically, and the associated costs are not likely to be large. The net result therefore supports a merits inquiry, and this conclusion remains valid even after process costs are added to the policy mix

An expert system for scheduling requests for communications Links between TDRSS and ERBS

An ERBS-TDRSS Contact Planning System (ERBS-TDRSS CPS) is described which uses a graphics interface and the NASA Transportable Interference Engine. The procedure involves transfer of the ERBS-TDRSS Ground Track Orbit Prediction data to the ERBS flight operations area, where the ERBS-TDRSS CPS automatically generates requests for TDRSS service. As requested events are rejected, alternative context sensitive strategies are employed to generate new requested events until a schedule is completed. A report generator builds schedule requests for separate ERBS-TDRSS contacts

Relational time for systems of oscillators

Using an elementary example based on two simple harmonic oscillators, we show how a relational time may be defined that leads to an approximate Schrodinger dynamics for subsystems, with corrections leading to an intrinsic decoherence in the energy eigenstates of the subsystem.Comment: Contribution to the Int. J. of Quant. Info. issue dedicated to the memory of Asher Pere

Pricing, Patent Loss and the Market For Pharmaceuticals

Empirical studies suggest that entry of generic competitors results in minimal decreases or even increases in brand-name drug prices as well as sharp declines in brand-name advertising. This paper examines circumstances under which this empirical pattern could be observed. The analysis focuses on models where the demand for brand-name pharmaceuticals is divided into two segments, only one of which is cross-price-sensitive. Brand-name firms are assumed to set price and advertising in a Stackelberg context; they allow for responses by generic producers but the latter take decisions by brand-name f inns as given. Brand-name price and advertising responses to entry are shown to depend upon the properties of the reduced-form brand-name demand function. Conditions for positive price responses and negative advertising responses are derived. We also examine the implications for brand-name price levels, and for the brand-name price response to entry, of health sector trends (such as increasing HMO enrollments) that may have the effect of expanding the size of the cross-price-sensitive segment of the market. The paper concludes with a review of recent empirical research and suggestions for future work on the effects of generic entry.

THE POLITICAL ECONOMY OF WATER QUALITY PROTECTION FROM AGRICULTURAL CHEMICALS

Environmental Economics and Policy,

Operational aspects of a spacecraft planning/scheduling expert system

Various operational aspects of the Earth Radiation Budget Satellite (ERBS) Tracking and Data Relay Satellite System (TDRSS) are described. The ERBS-TDRSS Contract Planning System is an expert system which has been used operationally since June 1987 by the ERBS Flight Operations Team (FOT) at Goddard Space Flight Center to build weekly schedules of requests for service from the TDRSS. The basic operation of the system and significant enhancements and changes are discussed

"Generic Entry and the Pricing of Pharmaceuticals"

During the 1980s the share of prescriptions sold by retail pharmacies that was accounted for by generic products roughly doubled. The price response to generic entry of brand-name products has been a source of controversy. In this paper we estimate models of price responses to generic entry in the market for brand-name and generic drugs. We study a sample of 32 drugs that lost patent protection during the early to mid-1980s. Our results provide strong evidence that brand-name prices increase after entry and are accompanied by large price decreases in the price of generic drugs.