Comment on the Calculation of the Angular Momentum and Mass for the (Anti-) Self Dual Charged Spinning BTZBTZ Black Hole

A recent paper [M. Kamata and T. Koikawa, Phys. Lett. {\bf B353} (1995) 196.] claimed to obtain the charged version of the $(2+1)$-dimensional spinning $BTZ$ black hole solution by assuming a (anti-) self dual condition imposed on the electric and magnetic fields. We point out that the angular momentum and mass diverge at spatial infinity and as a consequence the solution is unphysicalComment: 4 pages, Latex, no figures, final version to be publised in Phys. Lett.

Long-term Effects of Testing on the Recall of Nontested Materials

Testing, or memory retrieval, is a powerful way to enhance long-term retention of studied material. Recent studies have shown that testing can also benefit later retention of related but nontested material (a finding known as retrieval-induced facilitation, Chan, McDermott, & Roediger, 2006), but the long-term consequences of this benefit is unknown. In the current experiment three retention intervals—20 minutes, 24 hours, 7 days—were used to assess the effects of testing on subsequent recall of the nontested material. The results indicate that the magnitude of retrieval-induced facilitation, like that of the testing effect (i.e., the memorial benefit of testing on the tested material), increases with delay at the beginning (i.e., between 20 minutes and 24 hours) but asymptotes afterward (i.e., between 24 hours and 7 days). Theoretical and applied implications of this finding are discussed

When does Retrieval Induce Forgetting and When does it Induce Facilitation? Implications for Retrieval Inhibition, Testing Effect, and Text Processing

Retrieval practice can enhance long-term retention of the tested material (the testing effect), but it can also impair later recall of the nontested material – a phenomenon known as retrieval-induced forgetting (Anderson, M. C., Bjork, R. A., & Bjork, E. L. (1994). Remembering can cause forgetting: retrieval dynamics in long-term memory. Journal of Experimental Psychology: Learning, Memory, and Cognition, 20(5), 1063–1087). Recent research, however, has shown that retrieval practice can sometimes improve later recall of the nontested material – a phenomenon termed retrieval-induced facilitation (Chan, J. C. K., McDermott, K. B., & Roediger, H. L. (2006). Retrieval-induced facilitation: initially nontested material can benefit from prior testing of related material. Journal of Experimental Psychology: General, 135, 553–571). What drives these different effects? Two experiments were designed to examine the conditions under which retrieval induces forgetting and facilitation. Two variables, the level of integration invoked during encoding and the length of delay between retrieval practice and final test, were revealed as critical factors in determining whether testing facilitated or hindered later retrieval of the nontested information. A text processing framework is advanced to account for these findings

Spinning Black Holes in (2+1)-dimensional String and Dilaton Gravity

We present a new class of spinning black hole solutions in $(2+1)$-dimensional general relativity minimally coupled to a dilaton with potential $e^{b\phi}\Lambda$. When $b=4$, the corresponding spinning black hole is a solution of low energy $(2+1)$-dimensional string gravity. Apart from the limiting case of the $BTZ$ black hole, these spinning black holes have no inner horizon and a curvature singularity only at the origin. We compute the mass and angular momentum parameters of the solutions at spatial infinity, as well as their temperature and entropy.Comment: 8 pages, Latex, statements about mass of 2+1 Hirschmann and Welch magnetic solution corrected, in press in Phys. Lett.

Contextual Utility and Practicality: Cultural Research for the School Community in Hong Kong

As an intellectual project, is cultural studies actually ‘useless’ in dealing with issues closely tied to students’ everyday practices? In this article, the authors examine the problem through the case of teacher training and curriculum development in the context of educational reform in Hong Kong—in particular, through a community-interface project we are engaged in as cultural researchers at the moment

Temperature Control in Polyvinyl Chloride Production: Internal Model Control (IMC) and Proportional, Integral and Derivative (PID) controller Implementation.

The Polyvinyl Chloride (PVC) suspension polymerization process is an exothermic reaction which is carried out in a batch reactor

The Dark Side of Testing Memory: Repeated Retrieval Can Enhance Eyewitness Suggestibility

Eyewitnesses typically recount their experiences many times before trial. Such repeated retrieval can enhance memory retention of the witnessed event. However, recent studies (e.g., Chan, Thomas, & Bulevich, 2009) have found that initial retrieval can exacerbate eyewitness suggestibility to later misleading information—a finding termed retrieval-enhanced suggestibility (RES). Here we examined the influence of multiple retrieval attempts on eyewitness suggestibility to subsequent misinformation. In four experiments, we systematically varied the number of initial tests taken (between zero and six), the delay between initial testing and misinformation exposure (~30 min or 1 week), and whether initial testing was manipulated between- or within-subjects. University undergraduate students were used as participants. Overall, we found that eyewitness suggestibility increased as the number of initial tests increased, but this RES effect was qualified by the delay and by whether initial testing occurred in a within- or between-subjects manner. Specifically, the within-subjects RES effect was smaller than the between-subjects RES effect, possibly because of the influence of retrieval-induced forgetting/facilitation (Chan, 2009) when initial testing was manipulated within subjects. Moreover, consistent with the testing effect literature (Roediger & Karpicke, 2006), the benefits of repeated testing on later memory were stronger after a 1-week delay than after a 30-min delay, thus reducing the negative impact of RES in long-term situations. These findings suggest that conditions that are likely to occur in criminal investigations can either increase (repeated testing) or reduce (delay) the influence of RES, thus further demonstrating the complex relationship between eyewitness memory and repeated retrieval. (PsycINFO Database Record (c) 2012 APA, all rights reserved

Providing Corrective Feedback During Retrieval Practice Does Not Increase Retrieval-Induced Forgetting

Recalling a subset of studied materials can impair subsequent retrieval of related, nontested materials. In two experiments, we examined the influence of providing corrective feedback (no feedback, immediate feedback, delayed feedback) during retrieval practice on this retrieval-induced forgetting effect. Performance was assessed with category cued recall (e.g., recall all exemplars studied under Weather), category-and-stem cued recall (e.g., Weather–B___), and recognition. We report a dissociation between the effects of feedback on memory of the tested materials and the nontested materials. Whereas providing immediate or delayed feedback (compared to no feedback) improved recall and recognition of the tested items, it had no influence on retrieval-induced forgetting. These results are consistent with the inhibition account of retrieval-induced forgetting. From an applied perspective, this finding is encouraging for students and educators who use testing to foster learning

Telling a good story: The effects of memory retrieval and context processing on eyewitness suggestibility

Witnesses are likely to describe a crime many times before testifying or encountering misinformation about that crime. Research examining the effect of retrieval on later suggestibility has yielded mixed results. LaPaglia and Chan manipulated whether misinformation was presented in a narrative or misleading questions, and they found that retrieval increased suggestibility when misinformation was presented in a narrative, but reduced suggestibility when the same misinformation was presented in questions. In the current study, we aimed to address why these differences occurred. Specifically, we examined whether contextual detail and narrative coherence during misinformation exposure influenced the relation between retrieval and suggestibility. Participants watched a robbery video and some were questioned about the event afterwards. They were then exposed to misinformation presented in a narrative (Experiment 1) or questions (Experiment 2) before taking a final memory test. Testing enhanced suggestibility when the misinformation phase reinstated contextual information of the event, but not when the misinformation phase included few contextual details–regardless of whether the misinformation was in a narrative or questions. In Experiment 3, disrupting narrative coherence by randomizing the order of contextual information eliminated retrieval-enhanced suggestibility. Therefore, context processing during the post-event information phase influences whether retrieval enhances or reduces eyewitness suggestibility