Advance organizers: Encoding manipulations.

Investigated whether varying students' methods of encoding advance organizers would influence the memorability of the organizers and subsequent reading materials in 2 experiments involving a total of 121 undergraduates. In Exp I, 3 encoding procedures were contrasted in the reading of a 1,300-word essay: (a) a nonorganizer, read only control, (b) a condition that required Ss to deal with the semantic base of organizers, and (c) a condition that required Ss merely to read the organizer and list key words it contained. In addition, both true organizers and control organizers were used to allow a contrast of advance organizers with other, nonorganizer prefatory materials. The results indicate that when Ss dealt with the semantic base of organizers, memory for the organizers and the subsequent essay content was significantly greater than in other conditions. However, Ss who dealt with the semantic base of organizers required significantly more study time than other Ss. Exp II replicated Exp I but entailed only 3 conditions: (a) control, (b) read organizer and chapter only, and (c) paraphrase organizer and read chapter. In addition, the reading material used in this experiment was a 5,000-word essay. The results confirm those of Exp I, but in this instance no significant differences in study time were observed. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acute toxicity and behavioral responses of coho salmon (Oncorhynchus kisutch) and shiner perch (Cymatogaster aggregata) to chlorine in heated sea-water

The acute toxicity and behavioral response to chlorinated and heated sea-water was determined for coho salmon smolts and 1–3 month old shiner perch. LC₅₀'s were determined for 7.5, 15, 30 and 60 min exposure times; 13, 16 and 20°C (Δt = 0, 3, 7°C) temperatures and total residual oxidant (TRO) concentrations ranging from 0.077 to 1.035 mg l⁻¹. The mean 60 min LC₅₀ for shiner perch was significantly reduced (P ≤ 0.05) from 308 μg l⁻¹ TRO at 13°C to 230 μg l⁻¹ TRO at 20°C. The 60 min LC₅₀ for coho salmon decreased from 208 μg l⁻¹ TRO at 13°C to 130 μg l⁻¹ at 20°C. The LC₅₀'s for coho salmon in chlorinated sea-water averaged 55% of those for shiner perch. The relationship between TRO concentration, exposure time, and percent survival in chlorinated sea-water at 13°C is presented for both species.A significant (P ≤ 0.01) avoidance threshold for coho salmon occurred at 2 μg l⁻¹ TRO and was reinforced with increasing temperature. A significant (P ≤ 0.01) avoidance threshold for shiner perch occurred at 175 μg l⁻¹ TRO, while a significant preference (P ≤ 0.05 or 0.01) response at 16°C and 20°C occurred at 10, 25, 50 and 100 μg l⁻¹ TRO. The ecological implications of the toxicity tests and the behavioral responses are discussed.     

Effects of across-chapter signals on recall of text.

Investigated 2 forms of across-chapter text signals: "preview" sentences, which signal contents in upcoming chapters, and "recall" sentences, which are backward signals that signal back to previously read materials. These signals may influence readers' recall of text material by guiding their attention during reading. They also may facilitate readers' activation of memory representations of previous content, thereby enhancing integrative processing. Seven experiments examined the effects of preview and recall sentences. The results of 4 experiments indicated a clear signaling effect across chapters. In Exp IV, there were significantly longer inspection times and reaction times (RTs) to secondary probes in signaled than in unsignaled paragraphs. The results of Exp V indicate that backward-signaled materials were recalled at a significantly greater rate than unsignaled materials. In addition, the signaled materials in Ss' recalls were clustered together at a significantly greater rate than unsignaled materials. Results of Exp VII indicate significantly longer inspection times and RTs to secondary probe tasks in the reading of paragraphs containing recall sentences than in the reading of paragraphs not containing signals. Results indicate that across-chapter signals have a strong effect on readers' recall of prose. (PsycINFO Database Record (c) 2010 APA, all rights reserved)