Relative Effectiveness Of Various Methods Research Articles

The Principles of Economics Course: A Historical Perspective

The author's research provides an amusing and thoughtful account of what has happened to the teaching of the beginning course in economics over the past century and should cause the profession to reflect upon what is known for sure about the relative effectiveness of various methods of presenting the subject to students. As one example, what is the role of close personal contact between teacher and student (as indicated by class size) in providing a favorable environment for learning the art and/or the science of economics?

The major parameters affecting temperature inside inhalation chambers.

Variations in inhalation chamber temperature can produce alterations in animal physiology, metabolism of foreign compounds as well as the chemical interaction of pollutant aerosols. This report presents the results of an investigation of the different mechanisms of heat transfer in a 380 L inhalation chamber and discusses the relative effectiveness of various methods that may be used to maintain a uniform chamber temperature during animal exposures. The thermal characteristics of the inhalation chamber were studied using an array of 40 thermocouples, with and without rats in the chamber and with and without 5 cm fiber glass insulation surrounding the chamber. Temperature profiles were measured with different animal loadings and intake air temperatures. An effective heat transfer coefficient of 6.6 +/- 1.8 W/m2 degrees C was determined for the stainless steel walls of the chamber. Heat balance studies with rats in this chamber have shown that with room air intake at a flow rate of 100 L/min, the stainless steel chamber walls were effective at removing approximately ninety percent of the animal heat as compared to the airstream.

Relative effectiveness of methods for immunizing BALB/cwm mice to transplantable myelomonocytic leukemia

An experimental model of transplantable myelomonocytic leukemia (WEHI-3B) was developed in syngeneic BALB/cwm mice to characterize immune mechanisms in this disease. The relative effectiveness of various methods for immunizing mice to transplantable myelomonocytic cells was analyzed. When mice were immunized i.p. once a week for 3 successive weeks with cell preparations (10 7) inactivated by formalin they died at a faster rate than nonimmunized controls. When complete Freund's adjuvant was used to enhance the protective response immunized mice also died at a faster rate than the controls. If mice were immunized with various ratios of X-irradiated and viable tumor cells survival time was not increased. The most consistent result was accelerated death in the various experimental groups. When mice were immunized once weekly with X-ray inactivated cells (5000 R) for 3, 5 or 8 successive weeks, the survival frequency was approximately the same (70–80%) in all three test groups. However, animals immunized 5 times withstood a higher challenge dose of tumor cells than those immunized 3 times. The spacings between immunizing doses and challenge appeared to significantly affect the efficacy of immunization. The age of mice had a significant effect on the protective response. When mice 6 weeks of age or younger were immunized the survival frequency was < 30%, compared to 70–80% in mice 7 weeks to 8 months of age. Considered together the results of these studies show that tumor cells of the WEHI-3B line of transplantable myelomonocytic leukemia are similar to syngeneic P1798 transplantable lymphoma and the various BALB plasmacytomas in that they are only weakly immunogenic in the BALB/c strain. The results also suggest that the immunologic response of BALB/c mice to weakly antigenic tumors is under strong negative regulation.

A Reply to Robert Emans' 'Reaction to the Summary of the Second-Grade Phase of the Cooperative Research Program in Primary Reading Instruction'

Robert Emans (1969), in his reaction to the Summary of the Second-Grade Phase of the Cooperative Research Program in Primary Reading Instruction (Dykstra, 1968), took issue with Dykstra's interpretation of the implications of the study. He suggested that 1] Dykstra downgraded the importance of the findings regarding the relative effectiveness of various methods and materials, and that 2] Dykstra's suggestion that future research should focus on elements of the total learning situation rather than methods and materials was unwarranted.

Chronic thumb-sucking: The psychologic effects and the relative effectiveness of various methods of treatment

Chronic thumb-sucking: The psychologic effects and the relative effectiveness of various methods of treatment

Tuberculosis, Every Physician's Problem

This book, written by one of America's most distinguished authorities on tuberculosis, clearly reflects, in particular, his views concerning the relative effectiveness of various methods of tuberculosis control. It documents the remarkable decline of the contagion during the past few decades. Dr. Myers reviews the very favorable trends which have occurred in the state of Minnesota largely as a result of his inspiration, guidance and remarkable drive. For many years he has been emphasizing the importance of the tuberculin test as the single most useful guide in any tuberculosis control program.

The Heritability of Resistance to Death in the Fowl

INCREASING knowledge about the genetics of resistance to diseases in various animals and a better insight into the relative effectiveness of mass selection, family selection and progeny testing under various circumstances, have combined to make it seem practical now to undertake programs in this field which seemed to most breeders to be either unwise or premature a decade ago. Many investigations, especially in the last two decades, have shown clearly that differences in resistance to certain diseases are in part hereditary. However, the relative effectiveness of various methods of selection for improving such resistance is still often uncertain.The present study was undertaken to measure the extent or degree to which resistance to disease is inherited in the fowl, and thus to provide a guide for estimating how much reduction in mortality can reasonably be expected to result from various kinds of selection. Answers were sought to the following questions: .

Distribution Transformer Lightning-Protection Practice-II

TO DETERMINE the relative effectiveness of various methods of protecting distribution transformers from lightning an annual survey of operating companies was initiated in 1934 by the transmission and distribution committee of the Edison Electric Institute and continued through 1935 and 1936. In 1934 operating data were obtained from 38 companies, in 1935 from 43 companies, and in 1936 from 41 companies. The results for 1934 were presented in a previous paper. This paper presents a summary of the data for the three years and draws conclusions therefrom. It is only by collecting such data from a number of companies for numerous installations for a number of years will conclusive data be obtained so that annual variations in storm frequency and severity will be averaged. It is planned to continue the collection of these data for several years. In the future it is hoped that data for a sufficient number of years will be obtained from each company so that the troubles may be weighted by the isokeraunic level of each territory served.

Distribution transformer lightning-protection practice — II

TO DETERMINE the relative effectiveness of various methods of protecting distribution transformers from lightning an annual survey of operating companies was initiated in 1934 by the transmission and distribution committee of the Edison Electric Institute and continued through 1935 and 1936. In 1934 operating data were obtained from 38 companies, in 1935 from 43 companies, and in 1936 from 41 companies. The results for 1934 were presented in a previous paper. This paper presents a summary of the data for the three years and draws conclusions therefrom. It is only by collecting such data from a number of companies for numerous installations for a number of years will conclusive data be obtained so that annual variations in storm frequency and severity will be averaged. It is planned to continue the collection of these data for several years. In the future it is hoped that data for a sufficient number of years will be obtained from each company so that the troubles may be weighted by the isokeraunic level of each territory served.

Television Optics: an Introduction

IN view of the many discursive books on the practice of television, this text is opportune, in that it sets out for the first time in book form the relevant physical data on lenses, Kerr cells, and electron focusing, and the relative effectiveness of various methods of scanning. More significant is its scientific accuracy and completeness; no important detail seems to be omitted which has a bearing on the optical performance of the many types of system. With its extensive bibliography and logical layout, Mr. Myers's book should prove to be a very valuable source of reference for students for many years to come. Television Optics: an Introduction. L. M. Myers By. Pp. x + 338. (London: Sir Isaac Pitman and Sons, Ltd., 1936.) 30s. net.