Education for Democracy

Literacy skills taught in the elementary grades establish a good foundation but are not adequate for the demands of secondary content curriculum. In history, preservice teachers must be prepared with a solid content base along with the pedagogy for teaching that content. To better teach and enhance student writing, preservice teachers need to learn how to integrate discipline-specific literacy into their instruction, using instructional strategies that are explicitly taught with scaffold supports. The purpose of this article is to present instructional ideas and strategies designed to help students develop key cognitive skills in history and engage in deeper-level thinking as they learn to write like a historian. Each strategy is research-based and includes sample writing assignments.     

Revised Historical Viewpoints

Project-based learning is an example of powerful social studies learning in which student engage in active inquiry. Action civics is a relatively new educational practice in which students act as citizens through a cycle of research, action, and reflection about problems they care about in their community. Building Civic Bridges offers teachers a model for students to develop and enact inquiry-based projects that reflect positive, and active, civic dispositions.     

Some approaches to statistical analysis of a weather modification experiment

Data from a weather modification experiment are examined and a number of statistical analyses reported. The validity of earlier inferences is studied as are the utilities of various statistical methods. The experiment is described. The original analysis of North American Weather Consultants, who conducted the experiment, is reviewed. Data summarization is reported. A major approach to analysis is through the use of cloud-physics covari-ates in regression analyses. Finally, a multivariate analysis is discussed. It appears that the covariates may have been affected by treatment (cloud seeding) and that their use is invalid, not only reducing error variances but removing treatment effect. Some recommendations for improved design of similar future experiments are given in a concluding section, including preliminary trial use of blocking by storms.     

A model for comparisons with ordered categorical data

A model developed by Andrich for ordered categorical data is extended to develop tests for treatment effects with paired or matched samples. In particular, this includes analysis for pre-post studies and crossover designs. Some advantages of this model are that it allows for misclassification of subjects, yields reasonable conditional requirements for exact analysis, a normal approximation is good for all but the smallest of sample sizes, and it is relatively simple mathematically. Furthermore, the form of the tests derived are logical extensions of tests for unordered categories.     

In Memoriam: Frank Wilcoxon

A mosaic is a graphical display of cross-classified data in which each count is represented by a rectangle of area proportional to the count. The positions and sides of the rectangles are set to encourage comparisons between counts in the figures. Mosaics are useful for discovering unusually high or small counts and for discovering dependencies between variables. In principle, mosaics may be used for any number of cross-classifying variables, but six seems to be a practical maximum. A mosaic is given for a four-way classification of Nielsen ratings.     

Portfolio optimization: New capabilities and future methods

Summary  This paper addresses the problem of portfolio selection in finance. In many cases, currently available software to compute the efficient frontier runs into difficulty in problems with more than about 600 securities. To proceed beyond this size, it is often necessary to modify the problem in which case there is typically a loss of information. In this paper, we discuss a computer capability that can exactly compute mean-variance efficient frontiers of problems with up to 2,000 securities in very reasonable time (even if a problem’s covariance matrix is 100% dense). The paper also discusses an augmentation to the theory of portfolio selection that allows multiple objectives (such as dividends, liquidity, social responsibility, amount invested in R&D, and so forth) to be incorporated into the portfolio selection process. In such problems, the efficient set is no longer a “frontier,” but is now best described as a “surface” with the interesting property that it is composed of platelets (like on the back of a turtle). Moreover, the computer capability that can compute the exact efficient frontier of a mean-variance problem with up to 2,000 securities also has, after additional coding, the ability to compute exactly all platelets of the efficient surface of a tri-criterion portfolio problem with up to 400 securities.

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Zusammenfassung  In dieser Arbeit stellen wir einen leistungsf?higen Rechenalgorithmus vor, um den effizienten Rand (die nichtdominierten Alternativen) von Portfolio-Auswahlproblemen in der Finanzierung zu bestimmen. Wir bezeichnen den Berechnungsalgorithmus, der in Java programmiert ist, mit MPQ (multi-parametric quadratic programming). MPQ weist gegenüber bisherigen Berechnungsverfahren eine Reihe von Vorteilen auf: Es kann für umfangreiche Anwendungsf?lle genutzt werden, ist durch passable Rechenzeiten charakterisiert und kann die Menge effizienter Alternativen in einem Bruchteil bisher üblicher Rechenzeiten bestimmen.