Negotiating White science in rural Black America: A case for navigating the landscape of teacher knowledge domains

The purpose of this study was to explore the nature of requisite teacher knowledge for teaching lower-track science students. Using video accounts, student focus groups, and teacher reflections researchers documented missteps, dead-ends, and unfruitful trajectories informed by the teacher’s incoming knowledge and compared these instances to necessary modifications informed by students’ voices and cultural artifacts. Our study revealed the shifting nature of sociocultural and pedagogical content knowledge of the teacher immersed in a context unlike that he experienced as a student. Results showed that teachers of majority backgrounds could learn to teach diverse students with at least moderate success from the perspective of their students. Implications for research and teacher education in diverse settings are discussed.     

Montgomery multiplication over rings

Montgomery multiplication of two elements a and b of a finite field F_q is defined as abr^-1 where r is a fixed field element in . In this paper we define Montgomery multiplication of elements a(x) and b(x) in a polynomial ring modulo the ideal generated by a reducible polynomial f(x). We then show that Montgomery multiplication over a field represented by a polynomial ring modulo an irreducible pentanomial can be performed more efficiently in terms of time delay by embedding the field in a quotient of a polynomial ring modulo a reducible trinomial. The trinomial has a degree that is slightly higher than that of the pentanomial, thereby increasing the number of gates in the multiplier by a small amount.     

Overhyped Fad or Missed Opportunity? A History of Academic Libraries and the Social Web

The emergence of social media has radically transformed the way we create and consume information. These changes have in turn given rise to new models of librarianship centered on principles of participation, interaction, and collaboration. Over the last decade, academic libraries have eagerly adopted social media as a means of enhancing services and connecting with a new generation of users. But how exactly has this technology changed libraries? In what ways has the social web transformed library services or our relationships with users? This article attempts to assess the impact of social media on academic libraries in the United States through a review of the literature published since 2005. In particular, it looks at how academic libraries have used social media to improve or develop new services. By comparing published case studies with the theoretical literature, this article seeks to separate theory from practice and determine the extent to which the social web has transformed library practice. The author concludes that, despite several noteworthy examples, the majority of social library applications ultimately fail to live up to the transformative potential promised within the literature and that this failure may have more to do with philosophical rather than technical limitations.     

Effects of Applying Different Time Limits to a Proposed GRE Writing Test

In order to determine the role of time limits on both test performance and test validity, we asked approximately 300 volunteers–prospective graduate students–to each write two essays–one in a 40-minute time period and the other in 60 minutes. Analyses revealed that, on average, test performance was significantly better when examinees were given 60 minutes instead of 40. However, there was no interaction between test-taking style (fast vs. slow) and time limits. 'That is', examinees who described themselves as slow writers/test takers did not benefit any more (or any less) from generous time limits than did their quicker counterparts. In addition, there was no detectable effect of different time limits on the meaning of essay scores, as suggested by their relationship to several nontest indicators of writing ability.     

A vacuum tube amplifier for small direct voltages

A simple means for combining a small direct voltage with an alternating carrier is described. This consists of connecting the direct voltage in series with an alternating voltage of the same order of magnitude. The two are then passed through a copper oxide rectifier which suppresses one part of the cycle. The degree of suppression depends upon the magnitude of the direct voltage. The resulting fluctuating voltage can be amplified to any desired degree in a conventional amplifier.The theory for the simple case of pure resistance is worked out, with an example. The solution of the more general case with inductances is indicated.The practical circuit which has been used for the amplification of thermo-couple currents, and as a galvanometer power multiplier, is shown.