Plane turbulent buoyant jets. Part 1. Integral properties

An integral technique suggested for the analysis of turbulent jets by Corrsin & Uberoi (1950) and Morton, Taylor & Turner (1956) is re-examined in an attempt to improve the description of the entrainment. It is determined that the hypothesis of Priestley & Ball (1955), that the entrainment coefficient is a linear function of the jet Richardson number, is reasonable, and that two empirically determined plume parameters are sufficient to describe the transition of buoyant jets to plumes. The results of a series of experiments in which both time-averaged velocity and time-averaged temperature profiles were recorded in a substantial number of plane turbulent buoyant jets of varying initial Richardson numbers are used to verify the basic ideas. In addition, measurements of the mean tracer flux in a series of buoyant jets indicate that as much as 40% of the transport in plumes is by the turbulent flux

Unique Virtues of Plurality Rule: Generalizing May's Theorem

May's theorem famously shows that, in social decisions between two options, simple majority rule uniquely satisfies four appealing conditions. Although this result is often cited as a general argument for majority rule, it has never been extended beyond pairwise decisions. Here we generalize May's theorem to decisions between many options where voters each cast one vote. We show that, surprisingly, plurality rule uniquely satisfies May's conditions. Our result suggests a conditional defense of plurality rule: If a society's balloting procedure collects only a single vote from each voter, then plurality rule is the uniquely compelling procedure for electoral decisions. First version: 15 September 2004; this version version 22 December 2005.May's theorem, plurality rule, simple majority rule

Field Experiments on Anchoring of Economic Valuations

A pillar of behavioral research is the view that preferences are constructed during the value elicitation process, but it is unclear whether, and to what extent, such biases influence real market equilibria. This paper examines the “anchoring” phenomenon in the field. The first experiment produces evidence that inexperienced consumers can be anchored in the value elicitation process, yet there is little evidence that experienced agents are influenced by anchors. The second experiment finds that anchors have only transient effects on prices and quantities traded: aggregate market outcomes converge to the intersection of supply and demand after a few market periods.field experiment, anchoring, valuation, experience

A Plan for Small Group Discussion

Participation Training for Adult Education, written by Indiana University professors Paul Burgevin and John McKinley, describes in detail a unique small group discussion model. Certain aspects of this discussion technique have been found to be quite applicable to community problems that require thorough discussion by citizen groups before decisions are made and action is taken. The procedure allows for a certain amount of flexibility but demands logical thinking and orderly consideration of the items chosen for discussion. In this way, less time is wasted on extraneous matters and the group can better focus on the major issues at hand. Such an adaptation might resemble the following example.Reviewed October 1993

A two-dimensional sink in a density-stratified porous medium

A solution is offered for the flow induced by a two-dimensional line sink in a saturated, density-stratified porous medium. It is found that fluid is selectively withdrawn from a thin layer at the elevation of the line sink and not from the entire medium. The velocity distributions predicted by the theory are checked by experiments in a Hele–Shaw cell and good agreement found

Rural Neighborhoods for Crime Prevention

There is increasing concern throughout the state for the growing incidence of burglary, theft and vandalism in rural areas. Whatever the reasons, these crimes have increased sharply in the past few years. Rural residents are taking steps to assist law enforcement officials to deal with this growing problem. These efforts have come to be known as neighborhood crime prevention or neighborhood crime watches.Reviewed October 1993

Is the Endangered Species Act Endangering Species?

We develop theory and present a suite of theoretically consistent empirical measures to explore the extent to which market intervention inadvertently alters resource allocation in a sequentialmove principal/agent game. We showcase our approach empirically by exploring the extent to which the U.S. Endangered Species Act has altered land development patterns. We report evidence indicating significant acceleration of development directly after each of several events deemed likely to raise fears among owners of habitat land. Our preferred estimate suggests an overall acceleration of land development by roughly one year. We also find from complementary hedonic regression models that habitat parcels declined in value when the habitat map was published, which is consistent with our estimates of the degree of preemption. These results have clear implications for policymakers, who continue to discuss alternative regulatory frameworks for species preservation. More generally, our modeling strategies can be widely applied -- from any particular economic environment that has a sequential-move nature to the narrower case of the political economy of regulation.

Information Cascades: Evidence from An Experiment with Financial Market Professionals

Previous empirical studies of information cascades use either naturally occurring data or laboratory experiments with student subjects. We combine attractive elements from each of these lines of research by observing market professionals from the Chicago Board of Trade (CBOT) in a controlled environment. As a baseline, we compare their behavior to student choices in similar treatments. We further examine whether, and to what extent, cascade formation is influenced by both private signal strength and the quality of previous public signals, as well as decision heuristics that differ from Bayesian rationality. Analysis of over 1,500 individual decisions suggests that CBOT professionals are better able to discern the quality of public signals than their student counterparts. This leads to much different cascade formation. Further, while the behavior of students is consistent with the notion that losses loom larger than gains, market professionals are unaffected by the domain of earnings. These results are important in both a positive and normative sense.

The community attitude self-survey

"MP 104 9/69/5M""E. Frederick List is associate professor, Department of Regional and Community Affairs, University of Missouri--Columbia.""This pamphlet is primarily designed to assist those who are thinking about launching a community attitude survey. Our purpose is not to answer all the questions about such a survey, but to suggest that certain factors be taken into account during the planning stages. An early consideration of these factors will help you avoid some the oversights and shortcomings that have occurred in earlier surveys. The material we are presenting is based on observation of, and participation in, the planning and carrying out of dozens of community surveys over a period of 12 years. Most of these activities were joint community development efforts in which consultants from state universities were involved. Our suggestions are not in tended to replace more sophisticated research methods. They are meant for the lay citizen who is interested in a practical self-help approach to identifying community issues and problems. ln one sense this is "action research," for the subjects of the inquiry themselves seek the information needed and actually use the data gathered. The term community survey as we use it, will refer to the process of obtaining public opinion or attitudes through a printed questionnaire. lt should not be confused with community study which implies a search for facts and figures. ln many community development efforts a study is an outgrowth of the survey. As a matter of fact, one school of thought maintains that the community attitude survey is severely weakened if it is used to up-date census data, canvass the labor market, or serve as a retail buying habits indicator. These are of enough importance by themselves for special spot checks, samples, or complete studies to be run if warranted."--Introduction.By E. Frederick Lis