On the greatest lower bound to reliability

Certain ambiguities in a recent paper on the computation and statistics of the greatest lower bound are clarified.     

Medicine as a career: Choices and consequences

Medicine has traditionally been regarded as a rewarding career both financially and socially. How true, however, is that tradition in today's world of rising costs and decreasing revenues? The educational debt of the physician-in-training is steadily increasing, and currently does not affect specialty choice. As the cost of medical education continues to rise, the applicant pool begins to shrink, thereby possibly affecting the quality of future physicians. Once the physician has completed training however, the majority enjoy a positive return on investment. Their incomes generally fail to remain ahead of inflation, and therefore, have remained within a narrow band of $40,000 in 1970 dollars. Finally, the demand for physician services cannot be attributed solely to either the consumer (patient) or to the supplier (physician). Rather, the demand for medical services appears to be a unique combination of the two. In conclusion, medicine still is an attractive career path, but the choices and consequences are becoming much more demanding.     

Factors Related to Career Aspirations of New Entrants into a Stratified Occupational System

A transactional model of career aspirations is presented. Selected variables from the model were measured with a postal questionnaire completed by 346 new entrants into a stratified occupational system. Factors found to be strongly related to initial career aspiration levels included sex and educational qualifications. These variables were found to mediate other factor relationships with career aspirations.     

A simple test for heterogeneity of variance in complex factorial designs

A simple procedure for testing heterogeneity of variance is developed which generalizes readily to complex, multi-factor experimental designs. Monte Carlo Studies indicate that the Z-variance test statistic presented here yields results equivalent to other familiar tests for heterogeneity of variance in simple one-way designs where comparisons are feasible. The primary advantage of the Z-variance test is in the analysis of factorial effects on sample variances in more complex designs. An example involving a three-way factorial design is presented.     

A tactile stimulation device for measuring two-point and gap discrimination thresholds in humans

A device to measure two-point-discrimination and gap-discrimination thresholds is described. The apparatus is capable of controlled and reliable delivery of forces up to 42.50 g while determining point of skin contact and subsequent depth of skin indentation during threshold determination. Stimulus delivery is controlled by computer software that deactivates a solenoid, allowing a counterbalanced beam with one of two stimulus wheels mounted on its end to rise and stimulate the skin. Depth of skin indentation is recorded by hardware that monitors the output of a photocell reflecting the position of the beam. The apparatus allows complete computer control of all data acquisition and recording.     

There is No Such Thing as a Ceteris Paribus Law

In this paper I criticize the commonly accepted idea that the generalizations of the special sciences should be construed as ceteris paribus laws. This idea rests on mistaken assumptions about the role of laws in explanation and their relation to causal claims. Moreover, the major proposals in the literature for the analysis of ceteris paribus laws are, on their own terms, complete failures. I sketch a more adequate alternative account of the content of causal generalizations in the special sciences which I argue should replace the ceteris paribus conception. This revised version was published online in July 2006 with corrections to the Cover Date.     

New perspectives on the effects of action on perceptual and cognitive development

This special section was motivated by a resurgence in the view that it is impossible to investigate perceptual and cognitive development without considering how it is affected by, and intertwined with, infants' and children's action in the world. This view has long been foundational to the field, yet contemporary investigations of the effects of acting on cognition and perception have been limited. The research showcased in this section indicates that this trend is changing as researchers consider anew the ways in which cognition derives structure from action. The work presented here illustrates the breadth of these potential effects across ages and domains of development, and it highlights the breadth of methods that can be recruited to investigate them. This new research focus provides insight for the mechanisms by which action affects perception and cognition and at the same time reveals that much remains to be learned.