The effect of number and minimum duration of post-response-prevention escapes on the resistance to extinction of an avoidance response

After one-way avoidance training, rats were exposed, during avoidance response prevention, to light (CS-only) presentations or to light-shock (CS-US) pairings. Subgroups were then given 1, 5, or 10 trials during which they could escape immediately (unrestricted) or after 5 sec (restricted) by means of the previously conditioned avoidance response from a simultaneous light-shock compound. All animals were then exposed to avoidance extinction. The number of unrestricted escapes increased responding for CS-only animals, but had no significant effect on the performance of CS-US animals. Nevertheless, resistance to extinction was considerably less for CS-only animals given 10 unrestricted escapes than for CS-US animals given one unrestricted escape. One restricted escape had no more effect than one unrestricted escape for either response-prevention group. However, 5 restricted escapes elevated responding for CS-only animals to the level of CS-US animals. Extinction responding for CS-US animals increased significantly only after 10 restricted escapes. Since CS-only animals showed no further increase, resistance to extinction once more was greater for CS-US animals. These results, together with the very brief unrestricted escape latencies of CS-only animals, support a greater role for Pavlovian extinction than for response competition in the facilitation of avoidance extinction by CS-only response prevention. The fact that 10 restricted escapes were required to elevate resistance to extinction for CS-US animals over that obtained with one unrestricted escape attests to the effectiveness of Pavlovian conditioning during avoidance response prevention in elevating CS aversiveness to a near ceiling level.     

Sodium arsenite reduces severity of dextran sulfate sodium-induced ulcerative colitis in rats

The histopathological features and the associated clinical findings of ulcerative colitis (UC) are due to persistent inflammatory response in the colon mucosa. Interventions that suppress this response benefit UC patients. We tested whether sodium arsenite (SA) benefits rats with dextran sulfate sodium (DSS)-colitis. The DSS-colitis was induced by 5% DSS in drinking water. SA (10 mg/kg; intraperitoneally) was given 8 h before DSS treatment and then every 48 h for 3 cycles of 7,14 or 21 d. At the end of each cycle rats were sacrificed and colon sections processed for histological examination. DSS induced diarrhea, loose stools, hemoccult positive stools, gross bleeding, loss of body weight, loss of epithelium, crypt damage, depletion of goblet cells and infiltration of inflammatory cells. The severity of these changes increased ir the order of Cycles 1,2 and 3. Treatment of rats with SA significantly reduced this severity and improved the weight gain.     

An examination of the effect of customized reading modules on diverse secondary students’ reading comprehension and motivation

This research sought to add to a body of knowledge that is severely underrepresented in the scientific literature, the effects of technological tools on reading comprehension and reading motivation in diverse secondary students from lower socioeconomic backgrounds. The study implemented an independent silent reading (ISR) program across a 5-month semester in an urban public high school and included 145 participants from nine 10th grade literature classes. The control group took part in no ISR, one treatment group participated in weekly ISR read from a textbook, and another treatment group participated in weekly ISR read from a computer module designed to address essential components of reading. Students were measured on global reading comprehension, text-specific reading assessments, and reading motivation. After controlling for initial skill and disposition levels, the results indicated that students from both ISR groups made greater gains than the control group in global reading comprehension, while the computer reading module group outperformed the textbook group and the control on text-specific assignments and increased their reading motivation to a greater degree than those in the other conditions. This research offers much-needed data on secondary students?? reading achievement and disposition and provides evidence that ISR implemented through the use of instructional technology and cognitive tools has broad potential to address development in these areas.     

Conservation of indigenous medicinal botanicals in Ekiti State, Nigeria

INTRODUCTION Ekiti State (about 7000 km2, Inland area) is situ- ated between 7°25′ and 8°20′ North and 5°00′ and 6°00′ East in the rainforest belt of southwestern Ni- geria (EKSG, 1997; Kayode, 1999; 2000). The state which was previously rich in botanicals is now being confronted with massive deforestation due to increase in population, urbanization, uncontrolled logging, lumber being used as fuel and developmental activi- ties since the state was created in 1996. Although stud…     

Designing With Multiple Interactives: Five Common Pitfalls

Abstract Interactive museum exhibits are ubiquitous in science centers, and are becoming increasingly popular in art, history and cultural museums. At an interactive exhibit, visitors can act on the exhibit and the exhibit reacts. While there is much theoretical and empirical support for the idea that interactive features promote science learning, we believe that serious design problems can arise if an uncritical “more is better” approach is taken to interactivity. This article describes five common pitfalls of designing exhibits with high levels of interactivity or multiple interactive features: 1) multiple options with equal salience, 2) features allowing multiple users to interfere with one another, 3) options that encourage users to disrupt the phenomenon being displayed, 4) features that make the critical phenomenon difficult to find, and 5) secondary features that obscure the primary feature. Examples of each of the five problems are presented, and possible design solutions are offered.     

“Acquired” Equals Addition? Associating Verbs with Arithmetic Operations Impacts Word Problem Performance

Successful word problem performance often requires understanding the linguistic relations between characters and objects. However, the keyword method promotes associating specific words with mathematical operations while neglecting the situational context. Research has thoroughly investigated the detrimental effects of individuals associating relational terminology (e.g., “more”) with mathematical operations (e.g., “addition”). The current study expands upon this line of research by examining whether undergraduate students associate verbs with mathematical operations and if verbal associations affect word problem performance. Similar to relational terminology, the participants associated verbs with operations, which significantly impacted performance. The educational implications are discussed.     

Making Sense of Uncertainty in the Science Classroom

Science & Education - Uncertainty is ubiquitous in science, but scientific knowledge is often represented to the public and in educational contexts as certain and immutable. This contrast can...