The deterioration of central city schools: A tale of two cities (Detroit and Denver)

Conclusions While a great deal more work needs to be done to assess the factors contributing to the stability and instability of the local tax base, these findings do provide some basis for understanding why central cities have been constantly plagued by fiscal problems. While increasing the quality of public services may result in the in-migration of some upper-income families, the limited findings of this paper appear to suggest that this has limited significance as a policy objective. However, it would be worth some controlled experimentation on the part of central city school boards to test this hypothesis further. It may be that if the area allows the level of its expenditure to fall too low relative to surrounding areas, the tax base may fall below the critical level necessary to maintain a competitive level of services, and cumulative deterioration will follow unless the system is saved by some outside source of funds.It is hoped that these results, although they are limited, will stimulate further research, not only on the dynamic interaction of public and private decisions but also on the question of what structural changes may be possible to shift the whole function.I wish to express a debt to Alphonse Holtmann, Gail Cook, and Gebhard Long and my Economics 425 class for their helpful comments. Shortcomings that remain are, of course, the author's responsibility, but my 425 class will hear about them.     

Estimation of effect size from a series of independent experiments.

Extends statistical theory for procedures based on the Glass estimator of effect size for methods used in the quantitative synthesis of research. An unbiased estimator of effect size is given. A weighted estimator of effect size based on data from several experiments is defined and shown to be optimal (asymptotically efficient). An approximate (large-sample) test for homogeneity of effect size across experiments is also given. The results of an empirical sampling study show that the large-sample distributions of the weighted estimator and the homogeneity statistic are quite accurate when the experimental and control group sample sizes exceed 10 and the effect sizes are smaller than about 1.5. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An investigation of liquid carryover and sample residual for a high-throughput flow cytometer sample delivery system

The phenomenon of intersample contamination in air-segmented continuous-flow assays has been studied for many years, and new uses are being found for these sampling techniques every day. One application that has been developed recently employs a flow cytometer to conduct high-throughput screening assays of biological compounds. We have explored the sources of intersample contamination in the system and shown how methods developed previously can be applied to describe these phenomena. Using a simple model, we were able to accurately measure liquid film thickness in the sample tubing and demonstrate the effects of intersample contamination in a flow cytometer assay. Also, measures have been taken to reduce the level of intersample contamination in cytometric screening assays, helping to make the system a more viable tool for drug screening applications.     

"Priming effect" in conventionally reinforced rats.

Ran 15 male albino rats in alleys for water reinforcement with intertrial intervals (ITIs) similar to the intervals typically used in studies of intracranial reinforcement. When deprived over 15 hrs Ss ran faster with very short ITIs (7 sec) than with longer ITIs (95 sec). Comparisons with rats described in other studies running for intracranial reinforcement leads to the conclusion that, regardless of what kind of reinforcer is used, rats run faster for a reinforcer when ITIs are only seconds long rather than over a minute. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phosphorus removal in the activated sludge process

The results from this research suggest that both calcium phosphate precipitation and enhanced biological uptake play a role in phosphorus removal in the activated sludge process when a non-nitrifying, anaerobic-aerobic system is used to treat a low calcium wastewater. The primary removal mechanism was found to be biological uptake, as calcium phosphate precipitation accounted for only 15–27% of the total phosphorus removed. Calcium phosphate precipitation in the aerobic unit was enhanced because of the pH increase in that reactor. This was the result of low CO₂ production (indicated by low specific oxygen uptake values) and intense aeration which caused excessive CO₂ stripping in the aerobic unit     

Nonaqueous potentiometry of coal-derived asphaltenes and model nitrogen-containing compounds in acetophenone and nitrobenzene

A series of 34 nitrogen-containing compounds with a wide range of basicities was examined under differential nonaqueous potentiometric conditions in acetophenone and nitrobenzene. These compounds could be resolved into five classes based on pK_aand half-neutralization-potential (HNP) values. Asphaltenes isolated from the vacuum still overhead (VSO) and vacuum still bottoms (VSB) fractions of the H-coal process were titrated under similar conditions. The titration results of both asphaltenes indicated the presence of two classes of nitrogen-containing compounds, a titratable class of the pyridine-ring or aniline type and a nontitratable class.