Construct validity of the Illinois test of psycholinguistic abilities for a clinic population

The construct validity of the 10 primary ITPA subtests was investigated on a clinic population of 91 (66 males, 25 female) learning disabled children. Construct validity was determined by the degree to which each subtest measured discrete, independent abilities and the extent of subtest relationship to academic subject areas. Results via factor analysis and correlational analyses generally support the independence of the channel dimension, i.e., visual vs. auditory. While the process dimension, i.e., receptive, expressive, and associative, was not found to be an independent measure, the dimension of levels, i.e., representational vs. automatic, was substantiated for this clinical population. Implications of discrepancies in the channel dimension are discussed.     

A critique of the expectancy formula approach: Beating a dead horse?

The expectancy and severe discrepancy formulas, like those originally considered by the US. Office of Education (1976), provide the oldest but least defensible method of quantifying academic discrepancy. A logical and mathematical analysis reveals that all variations of this approach have several major weaknesses. First, the expectancy formulas themselves are predicated upon the very questionable assumption that achievement follows a straight line growth pattern, which raises questions about the accuracy of the resulting severe discrepancy values. Second, when discrepancy values are obtained by multiplying the expected values by a fractional constant, the approach is necessarily biased in the direction of applying a more stringent underachievement criterion for older and brighter children. Third, the formulas employ a grade equivalent scale that results in inconsistencies, one being that fewer arithmetic problems are identified. Finally, the expectancy approach does not consider errors in measurement or regression effects, and consequently produces serious identification errors. A variation of the expectancy approach involving a discrepancy ratio between obtained and expected achievement has the previously mentioned limitations, except the bias, and it produces scores that cannot be easily interpreted.     

Canadian science policy: Report number four revisited

We have just passed the fifth Anniversary of the publication of the Science Council of Canada's first best-seller — its Report No. 4: Towards a National Science Policy for Canada. When it appeared in October 1968, this report created quite a stir. It was the first definitive examination and evaluation of science-policy problems in this country. It helped to establish Canada as one of the countries anxious to improve the effectiveness of domestic scientific and technical activities under the leadership of the senior government. And it added lustre to the Council's own growing reputation.What has happened in the science-policy field in this country since the publication of Report No. 4? What has happened to the philosophy and recommendations set out in the report? What has the Science Council been doing since 1968? These are questions that will be discussed in this article.     

Efficient capture of circulating tumor cells with a novel immunocytochemical microfluidic device

Ability to perform cytogenetic interrogations on circulating tumor cells (CTCs) from the blood of cancer patients is vital for progressing toward targeted, individualized treatments. CTCs are rare compared to normal (bystander) blood cells, found in ratios as low as 1:10⁹. The most successful isolation techniques have been immunocytochemical technologies that label CTCs for separation based on unique surface antigens that distinguish them from normal bystander cells. The method discussed here utilizes biotin-tagged antibodies that bind selectively to CTCs. The antibodies are introduced into a suspension of blood cells intending that only CTCs will display surface biotin molecules. Next, the cell suspension is passed through a microfluidic channel that contains about 9000 transverse, streptavidin coated posts. A CTC making contact with a post has the opportunity to engage in a biotin-streptavidin reaction that immobilizes the cell. Bystander blood cells remain in suspension and pass through the channel. The goal of the present study is to establish the technical performance of these channels as a function of antigen density and operating conditions, especially flow rate. At 18 μL/min, over 70% of cells are captured at antigen densities greater than 30 000 sites/cell while 50% of cells are captured at antigen densities greater than 10 000. It is found that lower flow rates lead to decreasing cell capture probabilities, indicating that some streamlines develop which are never close enough to a post to allow cell-post contact. Future modeling and streamline studies using computational fluid dynamics software could aid in optimization of channel performance for capture of rare cells.     

Becoming Autonomous: Nonideal Theory and Educational Autonomy

Autonomy operates as a key term in debates about the rights of families to choose distinct approaches to education. Yet, what autonomy means is often complicated by the actual circumstances and contexts of schools, families, and children. In this essay, Terri S. Wilson and Matthew A. Ryg focus on the challenges involved in translating an ideal of educational autonomy into the “nonideal” contexts and circumstances that surround families' choices. Drawing on the methodological insights of Elizabeth Anderson and John Dewey, they sketch out a nonideal approach for exploring autonomy. Wilson and Ryg particularly focus on Dewey's notion of an ideal, his treatment of autonomy as a concept, and his view of the self. Such a nonideal approach draws attention toward the specific circumstances, habits, and environments that make autonomy possible. Wilson and Ryg illustrate the salience of this nonideal approach by exploring one example of an empirically engaged study of autonomy.