Super-Latent Inhibition of Conditioned Taste Preference with a Long Retention Interval

ERIC Educational Resources Information Center

De la Casa, L. G.; Marquez, R.; Lubow, R. E.

2009-01-01

A long delay inserted between conditioning and test phases of a 3-stage Latent Inhibition (LI) procedure produces differential effects on LI depending on the delay context. Thus, enhanced LI has been obtained when the delay is spent in a context that is different from the remaining experimental contexts, but not when it is the same. The present…

Do as I … Did! Long-term memory of imitative actions in dogs (Canis familiaris).

PubMed

Fugazza, Claudia; Pogány, Ákos; Miklósi, Ádám

2016-03-01

This study demonstrates long-term declarative memory of imitative actions in a non-human animal species. We tested 12 pet dogs for their ability to imitate human actions after retention intervals ranging from 1 to 24 h. For comparison, another 12 dogs were tested for the same actions without delay between demonstration and recall. Our test consisted of a modified version of the Do as I Do paradigm, combined with the two-action procedure to control for non-imitative processes. Imitative performance of dogs remained consistently high independent of increasing retention intervals, supporting the idea that dogs are able to retain mental representations of human actions for an extended period of time. The ability to imitate after such delays supports the use of long-term declarative memory.

Retention of Esperanto Is Affected by Delay-Interval Task and Item Closure: A Partial Resolution of the Delay-Retention Effect

ERIC Educational Resources Information Center

Brosvic, Gary M.; Epstein, Michael L.; Dihoff, Roberta E.; Cook, Michael L.

2006-01-01

The present studies were undertaken to examine the effects of manipulating delay-interval task (Study 1) and timing of feedback (Study 2) on acquisition and retention. Participants completed a 100-item cumulative final examination, which included 50 items from each laboratory examination, plus 50 entirely new items. Acquisition and retention were…

Text Structure and Retention of Prose.

ERIC Educational Resources Information Center

Zimmer, John W.

1985-01-01

The effects of text structure were studied using two kinds of reading materials: a standard text with headings and illustrations, as well as a nonstructured manuscript. The manuscript readers scored higher on delayed tests, generated more relevant ideas, and wrote better essays both immediately and after a delay. (Author/GDC)

Sleep confers a benefit for retention of statistical language learning in 6.5month old infants.

PubMed

Simon, Katharine N S; Werchan, Denise; Goldstein, Michael R; Sweeney, Lucia; Bootzin, Richard R; Nadel, Lynn; Gómez, Rebecca L

2017-04-01

Infants show robust ability to track transitional probabilities within language and can use this information to extract words from continuous speech. The degree to which infants remember these words across a delay is unknown. Given well-established benefits of sleep on long-term memory retention in adults, we examine whether sleep similarly facilitates memory in 6.5month olds. Infants listened to an artificial language for 7minutes, followed by a period of sleep or wakefulness. After a time-matched delay for sleep and wakefulness dyads, we measured retention using the head-turn-preference procedure. Infants who slept retained memory for the extracted words that was prone to interference during the test. Infants who remained awake showed no retention. Within the nap group, retention correlated with three electrophysiological measures (1) absolute theta across the brain, (2) absolute alpha across the brain, and (3) greater fronto-central slow wave activity (SWA). Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of Embodied Learning and Digital Platform on the Retention of Physics Content: Centripetal Force

PubMed Central

Johnson-Glenberg, Mina C.; Megowan-Romanowicz, Colleen; Birchfield, David A.; Savio-Ramos, Caroline

2016-01-01

Embodiment theory proposes that knowledge is grounded in sensorimotor systems, and that learning can be facilitated to the extent that lessons can be mapped to these systems. This study with 109 college-age participants addresses two overarching questions: (a) how are immediate and delayed learning gains affected by the degree to which a lesson is embodied, and (b) how do the affordances of three different educational platforms affect immediate and delayed learning? Six 50 min-long lessons on centripetal force were created. The first factor was the degree of embodiment with two levels: (1) low and (2) high. The second factor was platform with three levels: (1) a large scale “mixed reality” immersive environment containing both digital and hands-on components called SMALLab, (2) an interactive whiteboard system, and (3) a mouse-driven desktop computer. Pre-tests, post-tests, and 1-week follow-up (retention or delayed learning gains) tests were administered resulting in a 2 × 3 × 3 design. Two knowledge subtests were analyzed, one that relied on more declarative knowledge and one that relied on more generative knowledge, e.g., hand-drawing vectors. Regardless of condition, participants made significant immediate learning gains from pre-test to post-test. There were no significant main effects or interactions due to platform or embodiment on immediate learning. However, from post-test to follow-up the level of embodiment interacted significantly with time, such that participants in the high embodiment conditions performed better on the subtest devoted to generative knowledge questions. We posit that better retention of certain types of knowledge can be seen over time when more embodiment is present during the encoding phase. This sort of retention may not appear on more traditional factual/declarative tests. Educational technology designers should consider using more sensorimotor feedback and gestural congruency when designing and opportunities for instructor professional development need to be provided as well. PMID:27933009

Effects of Embodied Learning and Digital Platform on the Retention of Physics Content: Centripetal Force.

PubMed

Johnson-Glenberg, Mina C; Megowan-Romanowicz, Colleen; Birchfield, David A; Savio-Ramos, Caroline

2016-01-01

Embodiment theory proposes that knowledge is grounded in sensorimotor systems, and that learning can be facilitated to the extent that lessons can be mapped to these systems. This study with 109 college-age participants addresses two overarching questions: (a) how are immediate and delayed learning gains affected by the degree to which a lesson is embodied, and (b) how do the affordances of three different educational platforms affect immediate and delayed learning? Six 50 min-long lessons on centripetal force were created. The first factor was the degree of embodiment with two levels: (1) low and (2) high. The second factor was platform with three levels: (1) a large scale "mixed reality" immersive environment containing both digital and hands-on components called SMALLab , (2) an interactive whiteboard system, and (3) a mouse-driven desktop computer. Pre-tests, post-tests, and 1-week follow-up (retention or delayed learning gains) tests were administered resulting in a 2 × 3 × 3 design. Two knowledge subtests were analyzed, one that relied on more declarative knowledge and one that relied on more generative knowledge, e.g., hand-drawing vectors. Regardless of condition, participants made significant immediate learning gains from pre-test to post-test. There were no significant main effects or interactions due to platform or embodiment on immediate learning. However, from post-test to follow-up the level of embodiment interacted significantly with time, such that participants in the high embodiment conditions performed better on the subtest devoted to generative knowledge questions. We posit that better retention of certain types of knowledge can be seen over time when more embodiment is present during the encoding phase. This sort of retention may not appear on more traditional factual/declarative tests. Educational technology designers should consider using more sensorimotor feedback and gestural congruency when designing and opportunities for instructor professional development need to be provided as well.

Retention of Text Material under Cued and Uncued Recall and Open and Closed Book Conditions

ERIC Educational Resources Information Center

Nevid, Jeffrey S.; Pyun, Yea Seul; Cheney, Brianna

2016-01-01

Evidence supports the benefits of effortful processing in strengthening retention of newly learned material. The present study compared two forms of effortful processing, uncued (free) recall and cued recall, under both open and closed book conditions, on both immediate and delayed (one-week) test performance. Participants read a section of a…

Acquisition and Retention of Esperanto: The Case for Error Correction and Immediate Feedback

ERIC Educational Resources Information Center

Brosvic, Gary M.; Epstein, Michael L.; Dihoff, Roberta E.; Cook, Michael J.

2006-01-01

Participants completed 5 laboratory examinations during which the number of responses permitted (1 response, up to 4 responses) and the timing of feedback (no feedback control: Scantron form; delayed feedback: end-of-test, 24-hr delay; immediate feedback: assistant, response form) were manipulated. Participants completed a 100-item cumulative…

Practice and transfer of the frequency structures of continuous isometric force.

PubMed

King, Adam C; Newell, Karl M

2014-04-01

The present study examined the learning, retention and transfer of task outcome and the frequency-dependent properties of isometric force output dynamics. During practice participants produced isometric force to a moderately irregular target pattern either under a constant or variable presentation. Immediate and delayed retention tests examined the persistence of practice-induced changes of force output dynamics and transfer tests investigated performance to novel (low and high) irregular target patterns. The results showed that both constant and variable practice conditions exhibited similar reductions in task error but that the frequency-dependent properties were differentially modified across the entire bandwidth (0-12Hz) of force output dynamics as a function of practice. Task outcome exhibited persistent properties on the delayed retention test whereas the retention of faster time scales processes (i.e., 4-12Hz) of force output was mediated as a function of frequency structure. The structure of the force frequency components during early practice and following a rest interval was characterized by an enhanced emphasis on the slow time scales related to perceptual-motor feedback. The findings support the proposition that there are different time scales of learning at the levels of task outcome and the adaptive frequency bandwidths of force output dynamics. Copyright © 2014 Elsevier B.V. All rights reserved.

Teaching for understanding in medical classrooms using multimedia design principles.

PubMed

Issa, Nabil; Mayer, Richard E; Schuller, Mary; Wang, Edward; Shapiro, Michael B; DaRosa, Debra A

2013-04-01

In line with a recent report entitled Effective Use of Educational Technology in Medical Education from the Association of American Medical Colleges Institute for Improving Medical Education (AAMC-IME), this study examined whether revising a medical lecture based on evidence-based principles of multimedia design would lead to improved long-term transfer and retention in Year 3 medical students. A previous study yielded positive effects on an immediate retention test, but did not investigate long-term effects. In a pre-test/post-test control design, a cohort of 37 Year 3 medical students at a private, midwestern medical school received a bullet point-based PowerPoint™ lecture on shock developed by the instructor as part of their core curriculum (the traditional condition group). Another cohort of 43 similar medical students received a lecture covering identical content using slides redesigned according to Mayer's evidence-based principles of multimedia design (the modified condition group). Findings showed that the modified condition group significantly outscored the traditional condition group on delayed tests of transfer given 1 week (d = 0.83) and 4 weeks (d = 1.17) after instruction, and on delayed tests of retention given 1 week (d = 0.83) and 4 weeks (d = 0.79) after instruction. The modified condition group also significantly outperformed the traditional condition group on immediate tests of retention (d = 1.49) and transfer (d = 0.76). This study provides the first evidence that applying multimedia design principles to an actual medical lecture has significant effects on measures of learner understanding (i.e. long-term transfer and long-term retention). This work reinforces the need to apply the science of learning and instruction in medical education. © Blackwell Publishing Ltd 2013.

It Pays to Go Off-Track: Practicing with Error-Augmenting Haptic Feedback Facilitates Learning of a Curve-Tracing Task

PubMed Central

Williams, Camille K.; Tremblay, Luc; Carnahan, Heather

2016-01-01

Researchers in the domain of haptic training are now entering the long-standing debate regarding whether or not it is best to learn a skill by experiencing errors. Haptic training paradigms provide fertile ground for exploring how various theories about feedback, errors and physical guidance intersect during motor learning. Our objective was to determine how error minimizing, error augmenting and no haptic feedback while learning a self-paced curve-tracing task impact performance on delayed (1 day) retention and transfer tests, which indicate learning. We assessed performance using movement time and tracing error to calculate a measure of overall performance – the speed accuracy cost function. Our results showed that despite exhibiting the worst performance during skill acquisition, the error augmentation group had significantly better accuracy (but not overall performance) than the error minimization group on delayed retention and transfer tests. The control group’s performance fell between that of the two experimental groups but was not significantly different from either on the delayed retention test. We propose that the nature of the task (requiring online feedback to guide performance) coupled with the error augmentation group’s frequent off-target experience and rich experience of error-correction promoted information processing related to error-detection and error-correction that are essential for motor learning. PMID:28082937

Adrenergic enhancement of consolidation of object recognition memory.

PubMed

Dornelles, Arethuza; de Lima, Maria Noemia Martins; Grazziotin, Manoela; Presti-Torres, Juliana; Garcia, Vanessa Athaide; Scalco, Felipe Siciliani; Roesler, Rafael; Schröder, Nadja

2007-07-01

Extensive evidence indicates that epinephrine (EPI) modulates memory consolidation for emotionally arousing tasks in animals and human subjects. However, previous studies have not examined the effects of EPI on consolidation of recognition memory. Here we report that systemic administration of EPI enhances consolidation of memory for a novel object recognition (NOR) task under different training conditions. Control male rats given a systemic injection of saline (0.9% NaCl) immediately after NOR training showed significant memory retention when tested at 1.5 or 24, but not 96h after training. In contrast, rats given a post-training injection of EPI showed significant retention of NOR at all delays. In a second experiment using a different training condition, rats treated with EPI, but not SAL-treated animals, showed significant NOR retention at both 1.5 and 24-h delays. We next showed that the EPI-induced enhancement of retention tested at 96h after training was prevented by pretraining systemic administration of the beta-adrenoceptor antagonist propranolol. The findings suggest that, as previously observed in experiments using aversively motivated tasks, epinephrine modulates consolidation of recognition memory and that the effects require activation of beta-adrenoceptors.

Transfer of learning on a spatial memory task between the blind and sighted people.

PubMed

Akpinar, Selcuk; Popović, Stevo; Kirazci, Sadettin

2012-12-01

The purpose of this study was to analyze the effect of two different types of feedback on a spatial memory task between the blind and blindfolded-sighted participants. Participants tried to estimate the predetermined distance by using their dominant hands. Both blind and blindfolded-sighted groups were randomly divided into two feedback subgroups as "100% frequency" and "10% bandwidth". The score of the participants was given verbally to the participants as knowledge of results (KR). The target distance was set as 60 cm. Sixty acquisition trials were performed in 4 sets each including 15 repetition afterwards immediate and delayed retention tests were undertaken. Moreover, 24 hours past the delayed retention test, the participants completed 15 no-KR trials as a transfer test (target distance was 30 cm). The results of the statistical analyses revealed no significant differences for both acquisition and retention tests. However, a significant difference was found at transfer test. 100% frequency blind group performed significantly less accurate than all other groups. As a result, it can be concluded that different types of feedback have similar effect on spatial memory task used in this study. However, types of feedback can change the performance of accuracy on transferring this skill among the blind.

Immediate extinction causes a less durable loss of performance than delayed extinction following either fear or appetitive conditioning.

PubMed

Woods, Amanda M; Bouton, Mark E

2008-12-01

Five experiments with rat subjects compared the effects of immediate and delayed extinction on the durability of extinction learning. Three experiments examined extinction of fear conditioning (using the conditioned emotional response method), and two experiments examined extinction of appetitive conditioning (using the food-cup entry method). In all experiments, conditioning and extinction were accomplished in single sessions, and retention testing took place 24 h after extinction. In both fear and appetitive conditioning, immediate extinction (beginning 10 min after conditioning) caused a faster loss of responding than delayed extinction (beginning 24 h after conditioning). However, immediate extinction was less durable than delayed extinction: There was stronger spontaneous recovery during the final retention test. There was also substantial renewal of responding when the physical context was changed between immediate extinction and testing (Experiment 1). The results suggest that, in these two widely used conditioning preparations, immediate extinction does not erase or depotentiate the original learning, and instead creates a less permanent reduction in conditioned responding. Results did not support the possibility that the strong recovery after immediate extinction was due to a mismatch in the recent "context" provided by the presence or absence of a recent conditioning experience. Several other accounts are considered.

Retention of Implicit Sequence Learning in Persons who Stutter and Persons with Parkinson's Disease

PubMed Central

Smits-Bandstra, Sarah; Gracco, Vincent

2014-01-01

This study investigated the retention of implicit sequence learning in 14 persons with Parkinson's disease (PPD), 14 persons who stutter (PWS) and 14 control participants. Participants completed a nonsense syllable serial reaction time task in a 120-minute session. Participants named aloud four syllables in response to four visual stimuli. The syllables formed a repeating 8-item sequence not made known to participants. After one week, participants completed a 60-minute retention session that included an explicit learning questionnaire and a sequence generation task. PPD showed retention of general learning equivalent to controls but PWS's reaction times were significantly slower on early trials of the retention test relative to other groups. Controls showed implicit learning during the initial session that was retained on the retention test. In contrast, PPD and PWS did not demonstrate significant implicit learning until the retention test suggesting intact, but delayed, learning and retention of implicit sequencing skills. All groups demonstrated similar limited explicit sequence knowledge. Performance differences between PWS and PPD relative to controls during the initial session and on early retention trials indicated possible dysfunction of the cortico-striato-thalamo-cortical loop. The etiological implications for stuttering, and clinical implications for both populations, of this dysfunction are discussed. PMID:23844763

The Picmonic(®) Learning System: enhancing memory retention of medical sciences, using an audiovisual mnemonic Web-based learning platform.

PubMed

Yang, Adeel; Goel, Hersh; Bryan, Matthew; Robertson, Ron; Lim, Jane; Islam, Shehran; Speicher, Mark R

2014-01-01

Medical students are required to retain vast amounts of medical knowledge on the path to becoming physicians. To address this challenge, multimedia Web-based learning resources have been developed to supplement traditional text-based materials. The Picmonic(®) Learning System (PLS; Picmonic, Phoenix, AZ, USA) is a novel multimedia Web-based learning platform that delivers audiovisual mnemonics designed to improve memory retention of medical sciences. A single-center, randomized, subject-blinded, controlled study was conducted to compare the PLS with traditional text-based material for retention of medical science topics. Subjects were randomly assigned to use two different types of study materials covering several diseases. Subjects randomly assigned to the PLS group were given audiovisual mnemonics along with text-based materials, whereas subjects in the control group were given the same text-based materials with key terms highlighted. The primary endpoints were the differences in performance on immediate, 1 week, and 1 month delayed free-recall and paired-matching tests. The secondary endpoints were the difference in performance on a 1 week delayed multiple-choice test and self-reported satisfaction with the study materials. Differences were calculated using unpaired two-tailed t-tests. PLS group subjects demonstrated improvements of 65%, 161%, and 208% compared with control group subjects on free-recall tests conducted immediately, 1 week, and 1 month after study of materials, respectively. The results of performance on paired-matching tests showed an improvement of up to 331% for PLS group subjects. PLS group subjects also performed 55% greater than control group subjects on a 1 week delayed multiple choice test requiring higher-order thinking. The differences in test performance between the PLS group subjects and the control group subjects were statistically significant (P<0.001), and the PLS group subjects reported higher overall satisfaction with the material. The data of this pilot site demonstrate marked improvements in the retention of disease topics when using the PLS compared with traditional text-based materials. The use of the PLS in medical education is supported.

Learning From Tests: Facilitation of Delayed Recall by Initial Recognition Alternatives.

ERIC Educational Resources Information Center

Whitten, William B., II; Leonard, Janet Mauriello

1980-01-01

Two experiments were designed to determine the effects of multiple-choice recognition test alternatives on subsequent memory for the correct answers. Results of both experiments are interpreted as demonstrations of the principle that long-term retention is facilitated such that memory evaluation occurs during initial recognition tests. (Author/RD)

Verbal Cues Facilitate Memory Retrieval during Infancy

ERIC Educational Resources Information Center

Hayne, Harlene; Herbert, Jane

2004-01-01

In three experiments, 18-month-olds were tested in a deferred imitation paradigm. Some infants received verbal information during the demonstration and at the time of the test (full narration), and some did not (empty narration). When tested after a 4-week delay, infants given full narration exhibited superior retention relative to infants given…

The impact of cognitive load on delayed recall.

PubMed

Camos, Valérie; Portrat, Sophie

2015-08-01

Recent studies have suggested that long-term retention of items studied in a working memory span task depends on the refreshing of memory items-more specifically, on the number of refreshing opportunities. However, it was previously shown that refreshing depends on the cognitive load of the concurrent task introduced in the working memory span task. Thus, cognitive load should determine the long-term retention of items assessed in a delayed-recall test if such retention relies on refreshing. In two experiments, while the amount of refreshing opportunities remained constant, we varied the cognitive load of the concurrent task by either introducing tasks differing in their attentional demands or varying the pace of the concurrent task. To verify that this effect was related to refreshing and not to any maintenance mechanism, we also manipulated the availability of subvocal rehearsal. Replicating previous results, increasing cognitive load reduced immediate recall. This increase also had a detrimental effect on delayed recall. Conversely, the addition of concurrent articulation reduced immediate but not delayed recall. This study shows that both working and episodic memory traces depend on the cognitive load of the concurrent task, whereas the use of rehearsal affects only working memory performance. These findings add further evidence of the dissociation between subvocal rehearsal and attentional refreshing.

Decomposing the interaction between retention interval and study/test practice: The role of retrievability

PubMed Central

Jang, Yoonhee; Wixted, John T.; Pecher, Diane; Zeelenberg, René; Huber, David E.

2012-01-01

Even without feedback, test practice enhances delayed performance compared to study practice, but the size of the effect is variable across studies. We investigated the benefit of testing, separating initially retrievable items from initially non-retrievable items. In two experiments, an initial test determined item retrievability. Retrievable or non-retrievable items were subsequently presented for repeated study or test practice. Collapsing across items, in Experiment 1, we obtained the typical crossover interaction between retention interval and practice type. For retrievable items, however, the crossover interaction was quantitatively different, with a small study benefit for an immediate test and a larger testing benefit after a delay. For non-retrievable items, there was a large study benefit for an immediate test, but one week later there was no difference between the study and test practice conditions. In Experiment 2, initially non-retrievable items were given additional study followed by either an immediate test or even more additional study, and one week later performance did not differ between the two conditions. These results indicate that the effect size of study/test practice is due to the relative contribution of retrievable and non-retrievable items. PMID:22304454

Decomposing the interaction between retention interval and study/test practice: the role of retrievability.

PubMed

Jang, Yoonhee; Wixted, John T; Pecher, Diane; Zeelenberg, René; Huber, David E

2012-01-01

Even without feedback, test practice enhances delayed performance compared to study practice, but the size of the effect is variable across studies. We investigated the benefit of testing, separating initially retrievable items from initially nonretrievable items. In two experiments, an initial test determined item retrievability. Retrievable or nonretrievable items were subsequently presented for repeated study or test practice. Collapsing across items, in Experiment 1, we obtained the typical cross-over interaction between retention interval and practice type. For retrievable items, however, the cross-over interaction was quantitatively different, with a small study benefit for an immediate test and a larger testing benefit after a delay. For nonretrievable items, there was a large study benefit for an immediate test, but one week later there was no difference between the study and test practice conditions. In Experiment 2, initially nonretrievable items were given additional study followed by either an immediate test or even more additional study, and one week later performance did not differ between the two conditions. These results indicate that the effect size of study/test practice is due to the relative contribution of retrievable and nonretrievable items.

A Diffusion Model Analysis of Decision Biases Affecting Delayed Recognition of Emotional Stimuli.

PubMed

Bowen, Holly J; Spaniol, Julia; Patel, Ronak; Voss, Andreas

2016-01-01

Previous empirical work suggests that emotion can influence accuracy and cognitive biases underlying recognition memory, depending on the experimental conditions. The current study examines the effects of arousal and valence on delayed recognition memory using the diffusion model, which allows the separation of two decision biases thought to underlie memory: response bias and memory bias. Memory bias has not been given much attention in the literature but can provide insight into the retrieval dynamics of emotion modulated memory. Participants viewed emotional pictorial stimuli; half were given a recognition test 1-day later and the other half 7-days later. Analyses revealed that emotional valence generally evokes liberal responding, whereas high arousal evokes liberal responding only at a short retention interval. The memory bias analyses indicated that participants experienced greater familiarity with high-arousal compared to low-arousal items and this pattern became more pronounced as study-test lag increased; positive items evoke greater familiarity compared to negative and this pattern remained stable across retention interval. The findings provide insight into the separate contributions of valence and arousal to the cognitive mechanisms underlying delayed emotion modulated memory.

The effects of analogy-based instruction on concept learning and retention in a non-formal coral reef ecology program

NASA Astrophysics Data System (ADS)

Brylske, Alexander Frederick

While a number of instructional models focus on the use of analogies, research into their effectiveness in enhancing comprehension and retention of scientific concepts, particularly involving adult learners, has been limited. The purpose of this study was to determine the efficacy of using the common teaching strategy for comparing the function of a coral reef to that of a city by using an analogy-based instructional model termed FAR. The training program entitled "Marine Resource Management for Dive Professionals" (MRMDP) was developed for this study. It was targeted to professionals in the recreational scuba industry to improve their understanding of coal reef ecology, as well as orient them to pertinent marine resource management issues, and promote environmentally-responsible attitudes and diving practices among their clients. A quasi-experimental pre-post-delayed posttest control group design was used to explore five research questions and corresponding hypotheses. A 55-item researcher-developed test of coral reef ecology was administered pre and post instruction. The delayed posttest was self-administered by the subjects three weeks after course completion. Data on seven experiential variables hypothesized as research factors were collected. Ten MRMPD courses were taught in seven nations, involving 194 subjects (85 subjects in four control courses, 109 in six treatment course). The results were analyzed using multiple regression/correlation (MRC) techniques to determine: (1) any significant relationship between pretest performance and experiential variables, (2) treatment versus control group posttest performance, and (3) treatment versus control group delayed posttest performance. Within the treatment group, learning gains and retention were determined by t-test analysis. Results indicated: (1) all research factors except one were significant predictors of pretest scores in the presence of the covariate; (2) no significant difference was found between control and treatment groups' pretest scores; (3) a significant interaction effect from a MANCOVA analysis, and resulting aptitude-treatment interaction analysis, showed group membership had a differential effect on the posttest relative to pretest scores; (4) the contribution of group membership to delayed posttest performance was significant; and (5) the treatment out-performed the control group on the posttest and delayed posttest. T-test analyses of treatment group performance showed a significant positive gain and retention.

An Experimental Analysis of Memory Processing

ERIC Educational Resources Information Center

Wright, Anthony A.

2007-01-01

Rhesus monkeys were trained and tested in visual and auditory list-memory tasks with sequences of four travel pictures or four natural/environmental sounds followed by single test items. Acquisitions of the visual list-memory task are presented. Visual recency (last item) memory diminished with retention delay, and primacy (first item) memory…

RBANS memory percentage retention: No evidence of incremental validity beyond RBANS scores for diagnostic classification of mild cognitive impairment and dementia and for prediction of daily function.

PubMed

Jodouin, Kara A; O'Connell, Megan E; Morgan, Debra G

2017-01-01

RBANS percentage retention scores may be useful for diagnosis, but their incremental validity is unclear. Percentage retention versus RBANS immediate and delayed memory subtests and delayed index scores were compared for diagnostic classification and for prediction of function. Data from 173 memory clinic patients with an interdisciplinary diagnosis (no cognitive impairment, amnestic mild cognitive impairment [aMCI], and dementia due to Alzheimer's disease [AD]) and complete RBANS data were analyzed. Across diagnostic contrasts, list percentage retention classification accuracy was similar to List Learning delayed recall, but below the Delayed Memory Index (DMI). Similarly, for classifying no cognitive impairment versus aMCI or dementia due to AD, story percentage retention was similar to Story Memory subtests and below the DMI. For classifying aMCI versus AD; however, Story Memory exceeded the DMI, but was similar to Story Memory subtest scores. Similarly, for prediction of function percentage retention measures did not predict variance beyond that predicted by the RBANS subtest or index scores. In sum, there is no evidence that calculation of percentage retention for RBANS adds clinical utility beyond those provided by the standard RBANS scores.

Effects of Emotion on Associative Recognition: Valence and Retention Interval Matter

PubMed Central

Pierce, Benton H.; Kensinger, Elizabeth A.

2011-01-01

In two experiments, we examined the effects of emotional valence and arousal on associative binding. Participants studied negative, positive, and neutral word pairs, followed by an associative recognition test. In Experiment 1, with a short-delayed test, accuracy for intact pairs was equivalent across valences, whereas accuracy for rearranged pairs was lower for negative than for positive and neutral pairs. In Experiment 2, we tested participants after a one-week delay and found that accuracy was greater for intact negative than for intact neutral pairs, whereas rearranged pair accuracy was equivalent across valences. These results suggest that, although negative emotional valence impairs associative binding after a short delay, it may improve binding after a longer delay. The results also suggest that valence, as well as arousal, needs to be considered when examining the effects of emotion on associative memory. PMID:21401233

Feedback enhances the positive effects and reduces the negative effects of multiple-choice testing.

PubMed

Butler, Andrew C; Roediger, Henry L

2008-04-01

Multiple-choice tests are used frequently in higher education without much consideration of the impact this form of assessment has on learning. Multiple-choice testing enhances retention of the material tested (the testing effect); however, unlike other tests, multiple-choice can also be detrimental because it exposes students to misinformation in the form of lures. The selection of lures can lead students to acquire false knowledge (Roediger & Marsh, 2005). The present research investigated whether feedback could be used to boost the positive effects and reduce the negative effects of multiple-choice testing. Subjects studied passages and then received a multiple-choice test with immediate feedback, delayed feedback, or no feedback. In comparison with the no-feedback condition, both immediate and delayed feedback increased the proportion of correct responses and reduced the proportion of intrusions (i.e., lure responses from the initial multiple-choice test) on a delayed cued recall test. Educators should provide feedback when using multiple-choice tests.

A Diffusion Model Analysis of Decision Biases Affecting Delayed Recognition of Emotional Stimuli

PubMed Central

Bowen, Holly J.; Spaniol, Julia; Patel, Ronak; Voss, Andreas

2016-01-01

Previous empirical work suggests that emotion can influence accuracy and cognitive biases underlying recognition memory, depending on the experimental conditions. The current study examines the effects of arousal and valence on delayed recognition memory using the diffusion model, which allows the separation of two decision biases thought to underlie memory: response bias and memory bias. Memory bias has not been given much attention in the literature but can provide insight into the retrieval dynamics of emotion modulated memory. Participants viewed emotional pictorial stimuli; half were given a recognition test 1-day later and the other half 7-days later. Analyses revealed that emotional valence generally evokes liberal responding, whereas high arousal evokes liberal responding only at a short retention interval. The memory bias analyses indicated that participants experienced greater familiarity with high-arousal compared to low-arousal items and this pattern became more pronounced as study-test lag increased; positive items evoke greater familiarity compared to negative and this pattern remained stable across retention interval. The findings provide insight into the separate contributions of valence and arousal to the cognitive mechanisms underlying delayed emotion modulated memory. PMID:26784108

Item-location binding in working memory: is it hippocampus-dependent?

PubMed

Allen, Richard J; Vargha-Khadem, Faraneh; Baddeley, Alan D

2014-07-01

A general consensus is emerging that the hippocampus has an important and active role in the creation of new long-term memory representations of associations or bindings between elements. However, it is less clear whether this contribution can be extended to the creation of temporary bound representations in working memory, involving the retention of small numbers of items over short delays. We examined this by administering a series of recognition and recall tests of working memory for colour-location binding and object-location binding to a patient with highly selective hippocampal damage (Jon), and groups of control participants. Jon achieved high levels of accuracy in all working memory tests of recognition and recall binding across retention intervals of up to 10s. In contrast, Jon performed at chance on an unexpected delayed test of the same object-location binding information. These findings indicate a clear dissociation between working memory and long-term memory, with no evidence for a critical hippocampal contribution to item-location binding in working memory. Copyright © 2014 Elsevier Ltd. All rights reserved.

The effects of green Ocimum basilicum hydroalcoholic extract on retention and retrieval of memory in mice

PubMed Central

Sarahroodi, Shadi; Esmaeili, Somayyeh; Mikaili, Peyman; Hemmati, Zahra; Saberi, Yousof

2012-01-01

The purpose of this study was evaluation of green Ocimum basilicum (sweet basil) hydroalcoholic extract on memory retention and retrieval of mice by using passive avoidance apparatus. For this purpose, after weighting, coding and classifying the mice, they were grouped (n = 8) as follow as: test groups (electric shock plus sweet basil extract by doses: 100, 200, 400 and 800 mg/kg, i.p.), control group (Only electric shock) and blank group (electric shock plus normal saline). In all mentioned groups delay time of leaving the platform for both retention and retrieval test of memory was measured. In retention test, sweet basil extract was administered immediately after receiving electric shock and in retrieval test it was administered 24 hours after receiving electric shock. The results indicated that hydroalcoholic extract of green Ocimum basilicum significantly (P < 0.05) increased memory retention. The best response was achieved with 400 mg/Kg of the extract. Also, results showed that sweet basil extract significantly (P < 0.05) increased memory retrieval and the best result was achieved with 400 mg/Kg too. It can be concluded that memory enhancing effects of green Ocimum basilicum is because of antioxidant activity of flavonoids, tannins and terpenoids. PMID:23661866

Pigeons exhibit higher accuracy for chosen memory tests than for forced memory tests in duration matching-to-sample.

PubMed

Adams, Allison; Santi, Angelo

2011-03-01

Following training to match 2- and 8-sec durations of feederlight to red and green comparisons with a 0-sec baseline delay, pigeons were allowed to choose to take a memory test or to escape the memory test. The effects of sample omission, increases in retention interval, and variation in trial spacing on selection of the escape option and accuracy were studied. During initial testing, escaping the test did not increase as the task became more difficult, and there was no difference in accuracy between chosen and forced memory tests. However, with extended training, accuracy for chosen tests was significantly greater than for forced tests. In addition, two pigeons exhibited higher accuracy on chosen tests than on forced tests at the short retention interval and greater escape rates at the long retention interval. These results have not been obtained in previous studies with pigeons when the choice to take the test or to escape the test is given before test stimuli are presented. It appears that task-specific methodological factors may determine whether a particular species will exhibit the two behavioral effects that were initially proposed as potentially indicative of metacognition.

Sleep Can Reduce the Testing Effect: It Enhances Recall of Restudied Items but Can Leave Recall of Retrieved Items Unaffected

ERIC Educational Resources Information Center

Bäuml, Karl-Heinz T.; Holterman, Christoph; Abel, Magdalena

2014-01-01

The testing effect refers to the finding that retrieval practice in comparison to restudy of previously encoded contents can improve memory performance and reduce time-dependent forgetting. Naturally, long retention intervals include both wake and sleep delay, which can influence memory contents differently. In fact, sleep immediately after…

Highly Superior Autobiographical Memory: Quality and Quantity of Retention Over Time

PubMed Central

LePort, Aurora K. R.; Stark, Shauna M.; McGaugh, James L.; Stark, Craig E. L.

2016-01-01

Individuals who have Highly Superior Autobiographical Memory (HSAM) are able to recall, with considerable accuracy, details of daily experiences that occurred over many previous decades. The present study parametrically investigates the quantity and quality of details of autobiographical memories acquired 1-week, 1-month, 1-year, and 10-years prior in HSAMs and controls. In addition, we tested the consistency of details provided at the 1-week delay by testing the subjects 1 month later with a surprise assessment. At the 1-week delay, HSAMs and controls recalled an equivalent number of events. In contrast, HSAM recall performance was superior at more remote delays, with remarkable consistency following a 1-month delay. Further, we revealed a relationship between the consistency of recall and HSAMs’ obsessive–compulsive tendencies. These data suggest that HSAMs experience normal encoding, yet enhanced consolidation and later recall of autobiographical events. PMID:26834661

All of the above: When multiple correct response options enhance the testing effect.

PubMed

Bishara, Anthony J; Lanzo, Lauren A

2015-01-01

Previous research has shown that multiple choice tests often improve memory retention. However, the presence of incorrect lures often attenuates this memory benefit. The current research examined the effects of "all of the above" (AOTA) options. When such options are correct, no incorrect lures are present. In the first three experiments, a correct AOTA option on an initial test led to a larger memory benefit than no test and standard multiple choice test conditions. The benefits of a correct AOTA option occurred even without feedback on the initial test; for both 5-minute and 48-hour retention delays; and for both cued recall and multiple choice final test formats. In the final experiment, an AOTA question led to better memory retention than did a control condition that had identical timing and exposure to response options. However, the benefits relative to this control condition were similar regardless of the type of multiple choice test (AOTA or not). Results suggest that retrieval contributes to multiple choice testing effects. However, the extra testing effect from a correct AOTA option, rather than being due to more retrieval, might be due simply to more exposure to correct information.

Learning from Feedback: Spacing and the Delay-Retention Effect

ERIC Educational Resources Information Center

Smith, Troy A.; Kimball, Daniel R.

2010-01-01

Most modern research on the effects of feedback during learning has assumed that feedback is an error correction mechanism. Recent studies of feedback-timing effects have suggested that feedback might also strengthen initially correct responses. In an experiment involving cued recall of trivia facts, we directly tested several theories of…

Interactive Effects of Color Realism and Learners' IQ on Effectiveness of Visual Instruction.

ERIC Educational Resources Information Center

Berry, Louis H.; Dwyer, Francis M.

1982-01-01

Undergraduates of different levels of ability (IQ) profited differentially from color cueing of instructional materials pertaining to the human heart. Visualization was not equally effective in achievement of different educational objectives (drawing, identification, terminology, and comprehension tests). Delayed retention of material was not…

Circadian Rhythms in Human Memory.

ERIC Educational Resources Information Center

Folkard, Simon; Monk, Timothy H.

1980-01-01

Two experiments are described that examined the influence of time-of-day of presentation on immediate and delayed retention and its potential effects on retrieval from long-term memory. Time of presentation was found to influence both immediate and delayed (28 day) retention, but not retrieval from long-term memory. (Author/SJL)

HIV Diagnosis, Linkage to Care, and Retention among Men Who Have Sex with Men and Transgender Women in Guatemala City

PubMed Central

Barrington, Clare; Knudston, Kelly; Bailey, Olga Alicia Paz; Aguilar, Jose Manuel; Loya-Montiel, Marilu Itzel; Morales-Miranda, Sonia

2017-01-01

Men who have sex with men (MSM) and transgender women are disproportionately affected by HIV in Guatemala, yet little is known about their experiences with diagnosis, linkage to care, and retention. We conducted qualitative interviews with 26 MSM and transgender women living with HIV in Guatemala City. HIV diagnosis experiences changed over time with increasing asymptomatic testing at non-governmental organizations. Fear of the physical and social impacts of HIV delayed testing, acceptance of diagnosis, and linkage to HIV care. These fears were driven by layered stigma and discrimination due to non-normative gender expressions and/or sexual orientation. Retention-specific determinants included HIV clinic dynamics and limited employment opportunities. There is an urgent need to improve support systems for early testing and linkage to care and to expand employment opportunities. Stigma and discrimination must be addressed at the family, clinic and contextual levels to reduce fear of diagnosis and improve access to care. PMID:27818436

Understanding HIV care delays in the US South and the role of the social-level in HIV care engagement/retention: a qualitative study

PubMed Central

2014-01-01

Introduction In a significant geographical shift in the distribution of HIV infection, the US South - comprising 17 states - now has the greatest number of adults and adolescents with HIV (PLHIV) in the nation. More than 60% of PLHIV are not in HIV care in Alabama and Mississippi, contrasted with a national figure of 25%. Poorer HIV outcomes raise concerns about HIV-related inequities for southern PLHIV, which warrant further study. This qualitative study sought to understand experiences of low-income PLHIV on the AIDS Drug Assistance Program in engagement and retention in continuous HIV care in two sites in Alabama. Methods The study was designed using grounded theory. Semi-structured interviews with 25 PLHIV explored experiences with care linkage, reported factors and behaviors affecting engagement/retention in continuous HIV care, including socio-economic factors. To triangulate sources, 25 additional interviews were conducted with health and social service providers from the same clinics and AIDS Service Organizations where clients obtained services. Across the narratives, we used the HIV care continuum to map where care delays and drop out occurred. Using open coding, constant comparison and iterative data collection and analysis, we constructed a conceptual model illustrating how participants described their path to HIV care engagement and retention. Results Most respondents reported delayed HIV care, describing concentric factors: psychological distress, fear, lack of information, substance use, incarceration, lack of food, transport and housing. Stark health system drop out occurred immediately after receipt of HIV test results, with ART initiation generally occurring when individuals became ill. Findings highlight these enablers to care: Alabama's 'social infrastructure'; 'twinning' medical with social services, 'social enablers' who actively link PLHIV to care; and 'enabling spaces' that break down PLHIV isolation, facilitating HIV care linkage/retention. Conclusions Ryan White-funded programs, together with housing, food and psychological support were pre-conditions for participants' entry and retention in HIV care. The path to achieving continuous HIV care for individuals at risk of lack of entry or delayed HIV care requires robust social-level responses, like in Alabama, that address physical and mental health of clients and directly engage the particular social and economic contexts and vulnerabilities of southern PLHIV. PMID:24708752

Mood-congruent false memories persist over time.

PubMed

Knott, Lauren M; Thorley, Craig

2014-01-01

In this study, we examined the role of mood-congruency and retention interval on the false recognition of emotion laden items using the Deese/Roediger-McDermott (DRM) paradigm. Previous research has shown a mood-congruent false memory enhancement during immediate recognition tasks. The present study examined the persistence of this effect following a one-week delay. Participants were placed in a negative or neutral mood, presented with negative-emotion and neutral-emotion DRM word lists, and administered with both immediate and delayed recognition tests. Results showed that a negative mood state increased remember judgments for negative-emotion critical lures, in comparison to neutral-emotion critical lures, on both immediate and delayed testing. These findings are discussed in relation to theories of spreading activation and emotion-enhanced memory, with consideration of the applied forensic implications of such findings.

Effects of aniracetam on delayed matching-to-sample performance of monkeys and pigeons.

PubMed

Pontecorvo, M J; Evans, H L

1985-05-01

A 3-choice, variable-delay, matching-to-sample procedure was used to evaluate drugs in both pigeons and monkeys while tested under nearly-identical conditions. Aniracetam (Roche 13-5057) improved accuracy of matching at all retention intervals following oral administration (12.5, 25 and 50 mg/kg) to macaque monkeys, with a maximal effect at 25 mg/kg. Aniracetam also antagonized scopolamine-induced impairment of the monkey's performance. Intramuscular administration of these same doses of aniracetam produced a similar, but not significant trend toward improved matching accuracy in pigeons.

Testing a dynamic-field account of interactions between spatial attention and spatial working memory.

PubMed

Johnson, Jeffrey S; Spencer, John P

2016-05-01

Studies examining the relationship between spatial attention and spatial working memory (SWM) have shown that discrimination responses are faster for targets appearing at locations that are being maintained in SWM, and that location memory is impaired when attention is withdrawn during the delay. These observations support the proposal that sustained attention is required for successful retention in SWM: If attention is withdrawn, memory representations are likely to fail, increasing errors. In the present study, this proposal was reexamined in light of a neural-process model of SWM. On the basis of the model's functioning, we propose an alternative explanation for the observed decline in SWM performance when a secondary task is performed during retention: SWM representations drift systematically toward the location of targets appearing during the delay. To test this explanation, participants completed a color discrimination task during the delay interval of a spatial-recall task. In the critical shifting-attention condition, the color stimulus could appear either toward or away from the midline reference axis, relative to the memorized location. We hypothesized that if shifting attention during the delay leads to the failure of SWM representations, there should be an increase in the variance of recall errors, but no change in directional errors, regardless of the direction of the shift. Conversely, if shifting attention induces drift of SWM representations-as predicted by the model-systematic changes in the patterns of spatial-recall errors should occur that would depend on the direction of the shift. The results were consistent with the latter possibility-recall errors were biased toward the locations of discrimination targets appearing during the delay.

Testing a Dynamic Field Account of Interactions between Spatial Attention and Spatial Working Memory

PubMed Central

Johnson, Jeffrey S.; Spencer, John P.

2016-01-01

Studies examining the relationship between spatial attention and spatial working memory (SWM) have shown that discrimination responses are faster for targets appearing at locations that are being maintained in SWM, and that location memory is impaired when attention is withdrawn during the delay. These observations support the proposal that sustained attention is required for successful retention in SWM: if attention is withdrawn, memory representations are likely to fail, increasing errors. In the present study, this proposal is reexamined in light of a neural process model of SWM. On the basis of the model's functioning, we propose an alternative explanation for the observed decline in SWM performance when a secondary task is performed during retention: SWM representations drift systematically toward the location of targets appearing during the delay. To test this explanation, participants completed a color-discrimination task during the delay interval of a spatial recall task. In the critical shifting attention condition, the color stimulus could appear either toward or away from the memorized location relative to a midline reference axis. We hypothesized that if shifting attention during the delay leads to the failure of SWM representations, there should be an increase in the variance of recall errors but no change in directional error, regardless of the direction of the shift. Conversely, if shifting attention induces drift of SWM representations—as predicted by the model—there should be systematic changes in the pattern of spatial recall errors depending on the direction of the shift. Results were consistent with the latter possibility—recall errors were biased toward the location of discrimination targets appearing during the delay. PMID:26810574

Retention and Extinction of Delay Eyeblink Conditioning Are Modulated by Central Cannabinoids

ERIC Educational Resources Information Center

Steinmetz, Adam B.; Freeman, John H.

2011-01-01

Rats administered the cannabinoid agonist WIN55,212-2 or the antagonist SR141716A exhibit marked deficits during acquisition of delay eyeblink conditioning, as noted by Steinmetz and Freeman in an earlier study. However, the effects of these drugs on retention and extinction of eyeblink conditioning have not been assessed. The present study…

Prediction of delayed retention of antibodies in hydrophobic interaction chromatography from sequence using machine learning.

PubMed

Jain, Tushar; Boland, Todd; Lilov, Asparouh; Burnina, Irina; Brown, Michael; Xu, Yingda; Vásquez, Maximiliano

2017-12-01

The hydrophobicity of a monoclonal antibody is an important biophysical property relevant for its developability into a therapeutic. In addition to characterizing heterogeneity, Hydrophobic Interaction Chromatography (HIC) is an assay that is often used to quantify the hydrophobicity of an antibody to assess downstream risks. Earlier studies have shown that retention times in this assay can be correlated to amino-acid or atomic propensities weighted by the surface areas obtained from protein 3-dimensional structures. The goal of this study is to develop models to enable prediction of delayed HIC retention times directly from sequence. We utilize the randomforest machine learning approach to estimate the surface exposure of amino-acid side-chains in the variable region directly from the antibody sequence. We obtain mean-absolute errors of 4.6% for the prediction of surface exposure. Using experimental HIC data along with the estimated surface areas, we derive an amino-acid propensity scale that enables prediction of antibodies likely to have delayed retention times in the assay. We achieve a cross-validation Area Under Curve of 0.85 for the Receiver Operating Characteristic curve of our model. The low computational expense and high accuracy of this approach enables real-time assessment of hydrophobic character to enable prioritization of antibodies during the discovery process and rational engineering to reduce hydrophobic liabilities. Structure data, aligned sequences, experimental data and prediction scores for test-cases, and R scripts used in this work are provided as part of the Supplementary Material. tushar.jain@adimab.com. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Knowledge retention after an online tutorial: a randomized educational experiment among resident physicians.

PubMed

Bell, Douglas S; Harless, Charles E; Higa, Jerilyn K; Bjork, Elizabeth L; Bjork, Robert A; Bazargan, Mohsen; Mangione, Carol M

2008-08-01

The time course of physicians' knowledge retention after learning activities has not been well characterized. Understanding the time course of retention is critical to optimizing the reinforcement of knowledge. Educational follow-up experiment with knowledge retention measured at 1 of 6 randomly assigned time intervals (0-55 days) after an online tutorial covering 2 American Diabetes Association guidelines. Internal and family medicine residents. Multiple-choice knowledge tests, subject characteristics including critical appraisal skills, and learner satisfaction. Of 197 residents invited, 91 (46%) completed the tutorial and were randomized; of these, 87 (96%) provided complete follow-up data. Ninety-two percent of the subjects rated the tutorial as "very good" or "excellent." Mean knowledge scores increased from 50% before the tutorial to 76% among those tested immediately afterward. Score gains were only half as great at 3-8 days and no significant retention was measurable at 55 days. The shape of the retention curve corresponded with a 1/4-power transformation of the delay interval. In multivariate analyses, critical appraisal skills and participant age were associated with greater initial learning, but no participant characteristic significantly modified the rate of decline in retention. Education that appears successful from immediate posttests and learner evaluations can result in knowledge that is mostly lost to recall over the ensuing days and weeks. To achieve longer-term retention, physicians should review or otherwise reinforce new learning after as little as 1 week.

List blocking and longer retention intervals reveal an influence of gist processing for lexically ambiguous critical lures

PubMed Central

McNabb, Jaimie; Hutchison, Keith A.

2016-01-01

In two experiments, we examined veridical and false memory for lists of associates from two meanings (e.g., stumble, trip, harvest, pumpkin, etc.) that converged upon a single, lexically ambiguous critical lure (e.g., fall), in order to compare the activation-monitoring and fuzzy-trace false memory accounts. In Experiment 1, we presented study lists that were blocked or alternated by meaning (within subjects), followed by a free recall test completed immediately or after a 2.5-min delay. Correct recall was greater for blocked than for alternated lists. Critical-lure false recall was greater for blocked lists on an immediate test, whereas both list types produced equivalent false recall on a delayed test. In Experiment 2, lists blocked and alternated by meaning were presented via a between-subjects design, in order to eliminate possible list-type carryover effects. Correct recall replicated the result from Experiment 1; however, blocking lists increased false recall on delayed, but not on immediate, tests. Across the experiments, clustering correct recall by meaning increased across the delay selectively for the alternated lists. Our results suggest that thematic (i.e., gist) processes are influential for false recall, especially following a delay, a pattern consistent with fuzzy-trace theory. PMID:26105976

Long-term Transfer of Learning from Books and Videos during Toddlerhood

PubMed Central

Brito, Natalie; Barr, Rachel; McIntyre, Paula; Simcock, Gabrielle

2011-01-01

Television viewing and picture book reading are prevalent activities during toddlerhood and research has shown that toddlers can imitate from both books and videos after short delays (Barr & Hayne, 1999; Simcock & DeLoache, 2006). This is the first study to directly compare toddlers’ long-term retention rates for target actions learned from a video or book. Toddlers (N = 158) aged 18- and 24-months saw an experimenter demonstrating how to make a novel 3-step toy rattle via a pre-recorded video or a picture book. The toddlers’ imitation of the target actions was tested after a specific delay (e.g., 2 weeks, 4 weeks) and their performance was compared to that of age-matched controls who did not see a demonstration. The 18-month-olds retained the target actions for 2 weeks, exhibiting forgetting at 4 weeks, whereas the 24-month-olds retained the information for up to 4 weeks, exhibiting forgetting at 8 weeks. Retention rates for books and videos did not differ at either age. These findings demonstrate very impressive retention from a brief 2D media demonstration and they contribute to our overall understanding of long-term memory processes during infancy. PMID:21911223

Effect of organizational strategy on visual memory in patients with schizophrenia.

PubMed

Kim, Myung-Sun; Namgoong, Yoon; Youn, Tak

2008-08-01

The aim of the present study was to examine how copy organization mediated immediate recall among patients with schizophrenia using the Rey-Osterrieth Complex Figure Test (ROCF). The Boston Qualitative Scoring System (BQSS) was applied for qualitative and quantitative analyses of ROCF performances. Subjects included 20 patients with schizophrenia and 20 age- and gender-matched healthy controls. During the copy condition, the schizophrenia group and the control group differed in fragmentation; during the immediate recall condition, the two groups differed in configural presence and planning; and during the delayed recall condition, they differed in several qualitative measurements, including configural presence, cluster presence/placement, detail presence/placement, fragmentation, planning, and neatness. The two groups also differed in several quantitative measurements, including immediate presence and accuracy, immediate retention, delayed retention, and organization. Although organizational strategies used during the copy condition mediated the difference between the two groups during the immediate recall condition, group also had a significant direct effect on immediate recall. Schizophrenia patients are deficient in visual memory, and a piecemeal approach to the figure and organizational deficit seem to be related to the visual memory deficit. But schizophrenia patients also appeared to have some memory problems, including retention and/or retrieval deficits.

Long-term transfer of learning from books and video during toddlerhood.

PubMed

Brito, Natalie; Barr, Rachel; McIntyre, Paula; Simcock, Gabrielle

2012-01-01

Television viewing and picture book reading are prevalent activities during toddlerhood, and research has shown that toddlers can imitate from both books and videos after short delays. This is the first study to directly compare toddlers' long-term retention rates for target actions learned from a video or book. Toddlers (N=158) at 18- and 24-months of age saw an experimenter demonstrating how to make a novel three-step toy rattle via a prerecorded video or a picture book. The toddlers' imitation of the target actions was tested after a specific delay (e.g., 2, 4 weeks), and their performance was compared with that of age-matched controls who did not see a demonstration. The 18-month-olds retained the target actions for 2 weeks, exhibiting forgetting at 4 weeks, whereas the 24-month-olds retained the information for up to 4 weeks, exhibiting forgetting at 8 weeks. Retention rates for books and videos did not differ at either age. These findings demonstrate very impressive retention from a brief two-dimensional media demonstration, and they contribute to our overall understanding of long-term memory processes during infancy. Copyright © 2011 Elsevier Inc. All rights reserved.

Job satisfaction, work environment and successful ageing: Determinants of delaying retirement among acute care nurses.

PubMed

Wargo-Sugleris, Michele; Robbins, Wendie; Lane, Christianne Joy; Phillips, Linda R

2018-04-01

To determine the relationships between job satisfaction, work environment and successful ageing and how these factors relate to Registered Nurses' intent to retire. Although little studied, retention of older nurses by delaying early retirement, before age 65, is an important topic for research. Qualitative and quantitative studies have indicated that job satisfaction work environment and successful ageing are key motivators in acute care Registered Nurses retention and/or delaying retirement. This study was designed to provide information to administrators and policy makers about retaining older, experienced RNs longer and more productively. This was a correlational, descriptive, cross-sectional study. An online survey of acute care Registered Nurses (N = 2,789) aged 40 years or older working in Florida was conducted from September - October 2013. Participants completed items related to job satisfaction, work environment, successful ageing and individual characteristics. Hypotheses derived from the modified Ellenbecker's Job Retention Model were tested using regression analysis. Job satisfaction scores were high. Highest satisfaction was with scheduling issues and co-workers; lowest with advancement opportunities. Successful ageing scores were also high with 81% reporting excellent or good health. Work environment explained 55% of the variance in job satisfaction. Years to retirement were significantly associated with successful ageing (p < .001), age (p < .001) and income (p < .010). This study provides quantitative evidence that environment and successful ageing are important areas that have an impact on job satisfaction and delay of retirement in older nurses and further studies in these areas are warranted to expand on this knowledge. © 2017 John Wiley & Sons Ltd.

A Developmental Study of Short-Term Memory Characteristics for Kinesthetic Movement Information.

ERIC Educational Resources Information Center

Ashby, Alan A.

Age-related characteristics of children's short-term retention of kinesthetic movement information were examined in this study. Three age levels (6-, 8-, and 10-year old children) were tested for recall of preselected location movements on a linear slide apparatus. Immediate and delayed recall were used in 16 trials. The results indicate that…

The Role of the Hippocampus in Retaining Relational Information across Short Delays: The Importance of Memory Load

ERIC Educational Resources Information Center

Jeneson, Annette; Mauldin, Kristin N.; Hopkins, Ramona O.; Squire, Larry R.

2011-01-01

Patients with hippocampal damage are sometimes impaired at remembering information across delays as short as a few seconds. How are these impairments to be understood? One possibility is that retention of some kinds of information is critically dependent on the hippocampus, regardless of the retention interval and regardless of whether the task…

Injuries from non-retention in gillnet fisheries suppress reproductive maturation in escaped fish.

PubMed

Baker, Matthew R; Swanson, Penny; Young, Graham

2013-01-01

Exploitation of fisheries resources has unintended consequences, not only in the bycatch and discard of non-target organisms, but also in damage to targeted fish that are injured by gear but not landed (non-retention). Delayed mortality due to non-retention represents lost reproductive potential in exploited stocks, while not contributing to harvest. Our study examined the physiological mechanisms by which delayed mortality occurs and the extent to which injuries related to disentanglement from commercial gear compromise reproductive success in spawning stocks of Pacific salmon (Oncorhynchus spp.). We found evidence for elevated stress in fish injured via non-retention in gillnet fisheries. Plasma cortisol levels correlated with the severity of disentanglement injury and were elevated in fish that developed infections related to disentanglement injuries. We also analyzed sex steroid concentrations in females (estradiol-17β and 17,20β-dihydroxy-4-pregnen-3-one) to determine whether non-retention impairs reproductive potential in escaped individuals. We demonstrate evidence for delayed or inhibited maturation in fish with disentanglement injuries. These findings have important implications for effective conservation and management of exploited fish stocks and suggest means to improve spawning success in such stocks if retention in commercial fisheries is improved and incidental mortality reduced.

Injuries from Non-Retention in Gillnet Fisheries Suppress Reproductive Maturation in Escaped Fish

PubMed Central

Baker, Matthew R.; Swanson, Penny; Young, Graham

2013-01-01

Exploitation of fisheries resources has unintended consequences, not only in the bycatch and discard of non-target organisms, but also in damage to targeted fish that are injured by gear but not landed (non-retention). Delayed mortality due to non-retention represents lost reproductive potential in exploited stocks, while not contributing to harvest. Our study examined the physiological mechanisms by which delayed mortality occurs and the extent to which injuries related to disentanglement from commercial gear compromise reproductive success in spawning stocks of Pacific salmon (Oncorhynchus spp.). We found evidence for elevated stress in fish injured via non-retention in gillnet fisheries. Plasma cortisol levels correlated with the severity of disentanglement injury and were elevated in fish that developed infections related to disentanglement injuries. We also analyzed sex steroid concentrations in females (estradiol-17β and 17,20β-dihydroxy-4-pregnen-3-one) to determine whether non-retention impairs reproductive potential in escaped individuals. We demonstrate evidence for delayed or inhibited maturation in fish with disentanglement injuries. These findings have important implications for effective conservation and management of exploited fish stocks and suggest means to improve spawning success in such stocks if retention in commercial fisheries is improved and incidental mortality reduced. PMID:23894510

The dark side of testing memory: repeated retrieval can enhance eyewitness suggestibility.

PubMed

Chan, Jason C K; Lapaglia, Jessica A

2011-12-01

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.

The effectiveness of integration of virtual patients in a collaborative learning activity.

PubMed

Marei, Hesham F; Donkers, Jeroen; Van Merrienboer, Jeroen J G

2018-05-07

Virtual patients (VPs) have been recently integrated within different learning activities. To compare between the effect of using VPs in a collaborative learning activity and using VPs in an independent learning activity on students' knowledge acquisition, retention and transfer. For two different topics, respectively 82 and 76 dental students participated in teaching, learning and assessment sessions with VPs. Students from a female campus and from a male campus have been randomly assigned to condition (collaborative and independent), yielding four experimental groups. Each group received a lecture followed by a learning session using two VPs per topic. Students were administrated immediate and delayed written tests as well as transfer tests using two VPs to assess their knowledge in diagnosis and treatment. For the treatment items of the immediate and delayed written tests, females outperformed males in the collaborative VP group but not in the independent VP group. On the female campus, the use of VPs in a collaborative learning activity is more effective than its use as an independent learning activity in enhancing students' knowledge acquisition and retention. However, the collaborative use of VPs by itself is not enough to produce consistent results across different groups of students and attention should be given to all the factors that would affect students' interaction.

Effect of Time Delay on Recognition Memory for Pictures: The Modulatory Role of Emotion

PubMed Central

Wang, Bo

2014-01-01

This study investigated the modulatory role of emotion in the effect of time delay on recognition memory for pictures. Participants viewed neutral, positive and negative pictures, and took a recognition memory test 5 minutes, 24 hours, or 1 week after learning. The findings are: 1) For neutral, positive and negative pictures, overall recognition accuracy in the 5-min delay did not significantly differ from that in the 24-h delay. For neutral and positive pictures, overall recognition accuracy in the 1-week delay was lower than in the 24-h delay; for negative pictures, overall recognition in the 24-h and 1-week delay did not significantly differ. Therefore negative emotion modulates the effect of time delay on recognition memory, maintaining retention of overall recognition accuracy only within a certain frame of time. 2) For the three types of pictures, recollection and familiarity in the 5-min delay did not significantly differ from that in the 24-h and the 1-week delay. Thus emotion does not appear to modulate the effect of time delay on recollection and familiarity. However, recollection in the 24-h delay was higher than in the 1-week delay, whereas familiarity in the 24-h delay was lower than in the 1-week delay. PMID:24971457

Where Have I Been? Where Should I Go? Spatial Working Memory on a Radial Arm Maze in a Rat Model of Depression

PubMed Central

Richter, Sophie Helene; Zeuch, Benjamin; Lankisch, Katja; Gass, Peter; Durstewitz, Daniel; Vollmayr, Barbara

2013-01-01

Disturbances in cognitive functioning are among the most debilitating problems experienced by patients with major depression. Investigations of these deficits in animals help to extend and refine our understanding of human emotional disorder, while at the same time providing valid tools to study higher executive functions in animals. We employ the “learned helplessness” genetic rat model of depression in studying working memory using an eight arm radial maze procedure with temporal delay. This so-called delayed spatial win-shift task consists of three phases, training, delay and test, requiring rats to hold information on-line across a retention interval and making choices based on this information in the test phase. According to a 2×2 factorial design, working memory performance of thirty-one congenitally helpless (cLH) and non-helpless (cNLH) rats was tested on eighteen trials, additionally imposing two different delay durations, 30 s and 15 min, respectively. While not observing a general cognitive deficit in cLH rats, the delay length greatly influenced maze performance. Notably, performance was most impaired in cLH rats tested with the shorter 30 s delay, suggesting a stress-related disruption of attentional processes in rats that are more sensitive to stress. Our study provides direct animal homologues of clinically important measures in human research, and contributes to the non-invasive assessment of cognitive deficits associated with depression. PMID:23614050

Integrating across Episodes: Investigating the Long-term Accessibility of Self-derived Knowledge in 4-Year-Old Children

PubMed Central

Varga, Nicole L.; Stewart, Rebekah A.; Bauer, Patricia J.

2016-01-01

Semantic memory, defined as our store of knowledge about the world, provides representational support for all of our higher order cognitive functions. As such, it is crucial that the contents of semantic memory remain accessible over time. Although memory for knowledge learned through direct observation has been previously investigated, we know very little about the retention of knowledge derived through integration of information acquired across separate learning episodes. The present research investigated cross-episode integration in 4-year-old children. Participants were presented with novel facts via distinct story episodes and tested for knowledge extension through cross-episode integration, as well as for retention of the information over a 1-week delay. In Experiment 1, children retained the self-derived knowledge over the delay, though performance was primarily evidenced in a forced-choice format. In Experiment 2, we sought to facilitate the accessibility and robustness of self-derived knowledge by providing a verbal reminder after the delay. The accessibility of self-derived knowledge increased, irrespective of whether participants successfully demonstrated knowledge of the integration facts during the first visit. The results suggest knowledge extended through integration remains accessible after delays, even in a population in which this learning process is less robust. The findings also demonstrate the facilitative effect of reminders on the accessibility and further extension of knowledge over extended time periods. PMID:26774259

Bigger is better! Hippocampal volume and declarative memory performance in healthy young men.

PubMed

Pohlack, Sebastian T; Meyer, Patric; Cacciaglia, Raffaele; Liebscher, Claudia; Ridder, Stephanie; Flor, Herta

2014-01-01

The importance of the hippocampus for declarative memory processes is firmly established. Nevertheless, the issue of a correlation between declarative memory performance and hippocampal volume in healthy subjects still remains controversial. The aim of the present study was to investigate this relationship in more detail. For this purpose, 50 healthy young male participants performed the California Verbal Learning Test. Hippocampal volume was assessed by manual segmentation of high-resolution 3D magnetic resonance images. We found a significant positive correlation between putatively hippocampus-dependent memory measures like short-delay retention, long-delay retention and discriminability and percent hippocampal volume. No significant correlation with measures related to executive processes was found. In addition, percent amygdala volume was not related to any of these measures. Our data advance previous findings reported in studies of brain-damaged individuals in a large and homogeneous young healthy sample and are important for theories on the neural basis of episodic memory.

Reversing the Course of Forgetting

ERIC Educational Resources Information Center

White, K. Geoffrey; Brown, Glenn S.

2011-01-01

Forgetting functions were generated for pigeons in a delayed matching-to-sample task, in which accuracy decreased with increasing retention-interval duration. In baseline training with dark retention intervals, accuracy was high overall. Illumination of the experimental chamber by a houselight during the retention interval impaired performance…

A Preliminary Study of Bully and Victim Behavior in Old-for-Grade Students: Another Potential Hidden Cost of Grade Retention or Delayed School Entry

ERIC Educational Resources Information Center

Crothers, Laura M.; Schreiber, James B.; Schmitt, Ara J.; Bell, G. Ronald; Blasik, Jessica; Comstock, Leigh A.; Greisler, Michael J.; Keener, Dana; King, Jamie M.; Lipinski, John

2010-01-01

Mounting evidence suggests that being an old-for-grade student, as a result of grade retention or delayed school entry, is related to negative outcomes across various domains of functioning. No known study has examined the relations between old-for-grade status and specific childhood/adolescent bully and victim behaviors. The first purpose of this…

Discrimination training facilitates pigeons' performance on one-trial-per-day delayed matching of key location

PubMed Central

Willson, Robert J.; Wilkie, Donald M.

1991-01-01

Six pigeons were tested on a one-trial-per-day variant of delayed matching of key location. In one condition, a trial began with the illumination of a pair of quasi-randomly selected pecking keys in a large 10-key test box. Pigeons' pecks to one key (the sample) were reinforced with 8-second access to grain on a variable-interval 30-second schedule, whereas pecks to the other key (the distractor) had no scheduled consequences. In the second condition, the nonreinforced distractor was not presented. In both conditions, subjects were removed from the apparatus after 15 minutes and placed in a holding cage. Subjects were subsequently replaced in the box after a delay (retention interval) of 30 seconds and were reexposed to the illuminated sample and distractor keys for 1 minute. If a pigeon made more pecks to the sample during this interval, the distractor was extinguished and subsequent pecks to the sample were reinforced on the previous schedule for an additional 15 minutes. If, however, a pigeon made more pecks to the distractor, both keys were extinguished and the subject was returned to its home cage. For all subjects, matching-to-sample accuracy was higher in the first condition. In a second experiment, the retention interval was increased to 5, 15, and 30 minutes, and then to 1, 2, 4, 8, 12, and 24 hours. Most subjects remembered the correct key location for up to 4 hours, and in one case, up to 24 hours, demonstrating a spatial-memory proficiency far better than previously reported in this species on delayed matching tasks. The results are discussed in terms of the commonly held distinction between working and reference memory. PMID:16812633

Acquisition, retention and transfer of simulated laparoscopic tasks using fNIR and a contextual interference paradigm.

PubMed

Shewokis, Patricia A; Shariff, Faiz U; Liu, Yichuan; Ayaz, Hasan; Castellanos, Andres; Lind, D Scott

2017-02-01

Using functional near infrared spectroscopy, a noninvasive, optical brain imaging tool that monitors changes in hemodynamics within the prefrontal cortex (PFC), we assessed performance and cognitive effort during the acquisition, retention and transfer of multiple simulated laparoscopic tasks by novice learners within a contextual interference paradigm. Third-year medical students (n = 10) were randomized to either a blocked or random practice schedule. Across 3 days, students performed 108 acquisition trials of 3 laparoscopic tasks on the LapSim ® simulator followed by delayed retention and transfer tests. Performance metrics (Global score, Total time) and hemodynamic responses (total hemoglobin (μm)) were assessed during skill acquisition, retention and transfer. All acquisition tasks resulted in significant practice schedule X trial block interactions for the left medial anterior PFC. During retention and transfer, random performed the skills in less time and had lower total hemoglobin change in the right dorsolateral PFC than blocked. Compared with blocked, random practice resulted in enhanced learning through better performance and less cognitive load for retention and transfer of simulated laparoscopic tasks. Copyright © 2016 Elsevier Inc. All rights reserved.

Differentiation of subsequent memory effects between retrieval practice and elaborative study.

PubMed

Liu, Yi; Rosburg, Timm; Gao, Chuanji; Weber, Christine; Guo, Chunyan

2017-07-01

Retrieval practice enhances memory retention more than re-studying. The underlying mechanisms of this retrieval practice effect have remained widely unclear. According to the elaborative retrieval hypothesis, activation of elaborative information occurs to a larger extent during testing than re-studying. In contrast, the episodic context account has suggested that recollecting prior episodic information (especially the temporal context) contributes to memory retention. To adjudicate the distinction between these two accounts, the present study used the classical retrieval practice effect paradigm to compare retrieval practice and elaborative study. In an initial behavioral experiment, retrieval practice produced greater retention than elaboration and re-studying in a one-week delayed test. In a subsequent event-related potential (ERP) experiment, retrieval practice resulted in reliably superior accuracy in the delayed test compared to elaborative study. In the ERPs, a frontally distributed subsequent memory effect (SME), starting at 300ms, occurred in the elaborative study condition, but not in the retrieval practice condition. A parietal SME emerged in the retrieval practice condition from 500 to 700ms, but was absent in the elaborative study condition. After 700ms, a late SME was present in the retrieval practice condition, but not in the elaborative study condition. Moreover, SMEs lasted longer in retrieval practice than in elaboration. The frontal SME in the elaborative study condition might be related to semantic processing or working memory-based elaboration, whereas the parietal and widespread SME in the retrieval practice condition might be associated with episodic recollection processes. These findings contradict the elaborative retrieval theory, and suggest that contextual recollection rather than activation of semantic information contributes to the retrieval practice effect, supporting the episodic context account. Copyright © 2017. Published by Elsevier B.V.

Drift in Neural Population Activity Causes Working Memory to Deteriorate Over Time.

PubMed

Schneegans, Sebastian; Bays, Paul M

2018-05-23

Short-term memories are thought to be maintained in the form of sustained spiking activity in neural populations. Decreases in recall precision observed with increasing number of memorized items can be accounted for by a limit on total spiking activity, resulting in fewer spikes contributing to the representation of each individual item. Longer retention intervals likewise reduce recall precision, but it is unknown what changes in population activity produce this effect. One possibility is that spiking activity becomes attenuated over time, such that the same mechanism accounts for both effects of set size and retention duration. Alternatively, reduced performance may be caused by drift in the encoded value over time, without a decrease in overall spiking activity. Human participants of either sex performed a variable-delay cued recall task with a saccadic response, providing a precise measure of recall latency. Based on a spike integration model of decision making, if the effects of set size and retention duration are both caused by decreased spiking activity, we would predict a fixed relationship between recall precision and response latency across conditions. In contrast, the drift hypothesis predicts no systematic changes in latency with increasing delays. Our results show both an increase in latency with set size, and a decrease in response precision with longer delays within each set size, but no systematic increase in latency for increasing delay durations. These results were quantitatively reproduced by a model based on a limited neural resource in which working memories drift rather than decay with time. SIGNIFICANCE STATEMENT Rapid deterioration over seconds is a defining feature of short-term memory, but what mechanism drives this degradation of internal representations? Here, we extend a successful population coding model of working memory by introducing possible mechanisms of delay effects. We show that a decay in neural signal over time predicts that the time required for memory retrieval will increase with delay, whereas a random drift in the stored value predicts no effect of delay on retrieval time. Testing these predictions in a multi-item memory task with an eye movement response, we identified drift as a key mechanism of memory decline. These results provide evidence for a dynamic spiking basis for working memory, in contrast to recent proposals of activity-silent storage. Copyright © 2018 Schneegans and Bays.

Deficient attention modulation of lateralized alpha power in schizophrenia.

PubMed

Kustermann, Thomas; Rockstroh, Brigitte; Kienle, Johanna; Miller, Gregory A; Popov, Tzvetan

2016-06-01

Modulation of 8-14 Hz (alpha) activity in posterior brain regions is associated with covert attention deployment in visuospatial tasks. Alpha power decrease contralateral to to-be-attended stimuli is believed to foster subsequent processing, such as retention of task-relevant input. Degradation of this alpha-regulation mechanism may reflect an early stage of disturbed attention regulation contributing to impaired attention and working memory commonly found in schizophrenia. The present study tested this hypothesis of early disturbed attention regulation by examining alpha power modulation in a lateralized cued delayed response task in 14 schizophrenia patients (SZ) and 25 healthy controls (HC). Participants were instructed to remember the location of a 100-ms saccade-target cue in the left or right visual hemifield in order to perform a delayed saccade to that location after a retention interval. As expected, alpha power decrease during the retention interval was larger in contralateral than ipsilateral posterior regions, and SZ showed less of this lateralization than did HC. In particular, SZ failed to show hemifield-specific alpha modulation in posterior right hemisphere. Results suggest less efficient modulation of alpha oscillations that are considered critical for attention deployment and item encoding and, hence, may affect subsequent spatial working memory performance. © 2016 Society for Psychophysiological Research.

Retention of primitive reflexes and delayed motor development in very low birth weight infants.

PubMed

Marquis, P J; Ruiz, N A; Lundy, M S; Dillard, R G

1984-06-01

Primitive reflexes and motor development were evaluated in 127 very low birth weight (VLBW) infants (birth weight less than 1501 grams) at four months corrected age. The asymmetrical tonic neck reflex, tonic labyrinth reflex, and Moro reflex were assessed for each child. The ability of each child to reach (obtain a red ring) and roll were observed. The child's performance on the gross motor scale of the Denver Development Screening Test was recorded. Thirty-seven term infants were administered identical evaluations at four months of age. The VLBW infants retained stronger primitive reflexes and exhibited a significantly higher incidence of motor delays than term infants. Significant correlations existed between the strength of the primitive reflexes and early motor development for VLBW infants. This study confirms a high incidence of motor delays among VLBW infants and demonstrates a clear association between retained primitive reflexes and delayed motor development in VLBW infants.

Intraseptal infusion of oxotremorine impairs memory in a delayed-non-match-to-sample radial maze task.

PubMed

Bunce, J G; Sabolek, H R; Chrobak, J J

2003-01-01

The medial septal nucleus is part of the forebrain circuitry that supports memory. This nucleus is rich in cholinergic receptors and is a putative target for the development of cholinomimetic cognitive-enhancing drugs. Septal neurons, primarily cholinergic and GABAergic, innervate the entire hippocampal formation and regulate hippocampal formation physiology and emergent function. Direct intraseptal drug infusions can produce amnestic or promnestic effects depending upon the type of drug administered. However, intraseptal infusion of the cholinomimetic oxotremorine has been reported to produce both promnestic and amnestic effects when administered prior to task performance. The present study examined whether post-acquisition intraseptal infusion of oxotremorine would be promnestic or amnestic in a delayed-non-match-to-sample radial maze task. In this task rats must remember information about spatial locations visited during a daily sample session and maintain that information over extended retention intervals (hours) in order to perform accurately on the daily test session. Treatments may then be administered during the retention interval. Alterations in maze performance during the test session an hour or more after treatment evidences effects on memory. In the present study, intraseptal infusion of oxotremorine (1.0-10.0 microg) produced a linear dose-related impairment of memory performance. Importantly, we also observed disrupted performance on the day after treatment. This persistent deficit was related only to memory over the retention interval and did not affect indices of short-term memory (ability to avoid repetitive or proactive errors during both the pre- and post-delay sessions). The persistent deficit contrasts with the acute amnestic effects of other intraseptally administered drugs including the cholinomimetics carbachol and tacrine. Thus, intraseptal oxotremorine produced a preferential disruption of memory consolidation as well as a persistent alteration of medial septal circuits. These findings are discussed with regards to multi-stage models of hippocampal-dependent memory formation and the further development of therapeutic strategies in the treatment of mild cognitive impairment as well as age-related decline and Alzheimer's dementia.

Knowledge Retention after an Online Tutorial: A Randomized Educational Experiment among Resident Physicians

PubMed Central

Harless, Charles E.; Higa, Jerilyn K.; Bjork, Elizabeth L.; Bjork, Robert A.; Bazargan, Mohsen; Mangione, Carol M.

2008-01-01

BACKGROUND The time course of physicians’ knowledge retention after learning activities has not been well characterized. Understanding the time course of retention is critical to optimizing the reinforcement of knowledge. DESIGN Educational follow-up experiment with knowledge retention measured at 1 of 6 randomly assigned time intervals (0–55 days) after an online tutorial covering 2 American Diabetes Association guidelines. PARTICIPANTS Internal and family medicine residents. MEASUREMENTS Multiple-choice knowledge tests, subject characteristics including critical appraisal skills, and learner satisfaction. RESULTS Of 197 residents invited, 91 (46%) completed the tutorial and were randomized; of these, 87 (96%) provided complete follow-up data. Ninety-two percent of the subjects rated the tutorial as “very good” or “excellent.” Mean knowledge scores increased from 50% before the tutorial to 76% among those tested immediately afterward. Score gains were only half as great at 3–8 days and no significant retention was measurable at 55 days. The shape of the retention curve corresponded with a 1/4-power transformation of the delay interval. In multivariate analyses, critical appraisal skills and participant age were associated with greater initial learning, but no participant characteristic significantly modified the rate of decline in retention. CONCLUSIONS Education that appears successful from immediate posttests and learner evaluations can result in knowledge that is mostly lost to recall over the ensuing days and weeks. To achieve longer-term retention, physicians should review or otherwise reinforce new learning after as little as 1 week. Electronic supplementary material The online version of this article (doi:10.1007/s11606-008-0604-2) contains supplementary material, which is available to authorized users. PMID:18446414

Capturing real-life forgetting in transient epileptic amnesia via an incidental memory test.

PubMed

Hoefeijzers, Serge; Zeman, Adam; Della Sala, Sergio; Dewar, Michaela

2017-12-13

Transient epileptic amnesia (TEA) is an epileptic syndrome characterized by recurrent, brief episodes of amnesia. Patients with TEA often complain of interictal (between attacks) retention deficits, characterised by an 'evaporation' of memories for recent events over days to weeks. Clinical tests of anterograde memory often fail to corroborate these complaints as TEA patients commonly perform within the normal range after the standard 10-30-min delay period. Modified laboratory tests that include a 1-3 week delay period frequently reveal clear evidence of 'accelerated long-term forgetting' (ALF). However, they are not used routinely and lack ecological validity. In the present study we examined whether 'real-life' ALF can be captured via a controlled incidental memory test in TEA patients. To this end, the experimenter told 27 TEA patients and 32 controls a well-rehearsed amusing story, apparently as a way of making light conversation before starting a set of research experiments. Without prior warning, the experimenter subsequently probed the participants' memory of this story via tests of free recall and forced choice recognition after 30 min or 1 week. After 30 min retention was comparable in TEA patients and controls. After 1 week TEA patients retained significantly less story material than controls, and significant ALF was revealed in the TEA patients in the recognition test. Our data show that ALF in a 'real-life' situation can occur even when standard memory tests indicate normal memory function. Moreover, our data suggest that incidental memory tests can capture real-life ALF, and that forced-choice recognition tests might be more sensitive than free recall tests for the detection of real-life ALF. Copyright © 2017 Elsevier Ltd. All rights reserved.

Immediate and delayed recall of a small-scale spatial array.

PubMed

Tlauka, Michael; Donaldson, Phillip; Bonnar, Daniel

2015-01-01

The study examined people's spatial memory of a small-scale array of objects. Earlier work has primarily relied on short-retention intervals, and to date it is not known whether performance is affected by longer intervals between learning and recall. In the present investigation, university students studied seven target objects. Recall was tested immediately after learning and after an interval of seven days. Performance was found to be similar in the immediate and delayed conditions, and the results suggested that recall was facilitated by egocentric and intrinsic cues. The findings are discussed with reference to recent investigations that have shown task parameters can influence spatial recall.

Post retention: the effect of sequence of post-space preparation, cementation time, and different sealers.

PubMed

Boone, K J; Murchison, D F; Schindler, W G; Walker, W A

2001-12-01

Many endodontic sealers contain constituents that have been shown to inhibit the polymerization of resin cements. This may be important when prefabricated posts are cemented at the same appointment as root canal obturation. This study evaluated the effects of cementing posts with a resin cement immediately or at a delayed time period after obturation using Roth's 801 Elite Grade or AH26 sealer cements. The contribution of mechanical post-space preparation was also assessed as a critical variable. One hundred twenty extracted canines were randomly divided into eight experimental groups. The variables evaluated were the order of post preparation (either before or after obturation), the type of sealer used, and the time of post cementation. All teeth received a stainless steel #6 Parapost XP cemented with a resin cement, Panavia 21. Each experimental group underwent tensile testing for retention using an Instron universal testing machine. For both sealers posts cemented in teeth in which the canal was obturated before post-space preparation and thus had sealer-contaminated dentin removed by the space preparation procedure had significantly higher retentive values than those obturated after post-space preparation in which contaminated dentin might remain. Sealer used and time of cementation had no specific effect on retention. Achieving a clean, "freshened" dentinal surface during mechanical post-space preparation seems to be a critical variable for post retention when a resin cement is used.

A randomized controlled trial of high-fidelity simulation versus lecture-based education in preclinical medical students.

PubMed

Alluri, Ram Kiran; Tsing, Pamela; Lee, Edward; Napolitano, Jason

2016-01-01

The purpose of this study was to compare the efficacy of simulation versus lecture-based education among preclinical medical students. Twenty medical students participated in this randomized, controlled crossover study. Students were randomized to four groups. Each group received two simulations and two lectures covering four different topics. Students were administered a pre-test, post-test and delayed post-test. The mean percentage of questions answered correctly on each test was calculated. The mean of each student's change in score across the three tests was used to compare simulation- versus lecture-based education. Students in both the simulation and lecture groups demonstrated improvement between the pre-test and post-test (p < 0.05). Students in the simulation group demonstrated improvement between the immediate post-test and delayed post-test (p < 0.05), while students in the lecture group did not demonstrate improvement (p > 0.05). When comparing interventions, the change in score between the pre-test and post-test was similar among both the groups (p > 0.05). The change in score between the post-test and delayed post-test was greater in the simulation group (p < 0.05). High-fidelity simulation may serve as a viable didactic platform for preclinical medical education. Our study demonstrated equivalent immediate knowledge gain and superior long-term knowledge retention in comparison to lectures.

Practicing more retrieval routes leads to greater memory retention.

PubMed

Zheng, Jun; Zhang, Wei; Li, Tongtong; Liu, Zhaomin; Luo, Liang

2016-09-01

A wealth of research has shown that retrieval practice plays a significant role in improving memory retention. The current study focused on one simple yet rarely examined question: would repeated retrieval using two different retrieval routes or using the same retrieval route twice lead to greater long-term memory retention? Participants elaborately learned 22 Japanese-Chinese translation word pairs using two different mediators. Half an hour after the initial study phase, the participants completed two retrieval sessions using either one mediator (Tm1Tm1) or two different mediators (Tm1Tm2). On the final test, which was performed 1week after the retrieval practice phase, the participants received only the cue with a request to report the mediator (M1 or M2) followed by the target (Experiment 1) or only the mediator (M1 or M2) with a request to report the target (Experiment 2). The results of Experiment 1 indicated that the participants who practiced under the Tm1Tm2 condition exhibited greater target retention than those who practiced under the Tm1Tm1 condition. This difference in performance was due to the significant disadvantage in mediator retrieval and decoding of the unpracticed mediator under the Tm1Tm1 condition. Although mediators were provided to participants on the final test in Experiment 2, decoding of the unpracticed mediators remained less effective than decoding of the practiced mediators. We conclude that practicing multiple retrieval routes leads to greater memory retention than focusing on a single retrieval route. Thus, increasing retrieval variability during repeated retrieval practice indeed significantly improves long-term retention in a delay test. Copyright © 2016 Elsevier B.V. All rights reserved.

An Experimental Analysis of Memory Processing

PubMed Central

Wright, Anthony A

2007-01-01

Rhesus monkeys were trained and tested in visual and auditory list-memory tasks with sequences of four travel pictures or four natural/environmental sounds followed by single test items. Acquisitions of the visual list-memory task are presented. Visual recency (last item) memory diminished with retention delay, and primacy (first item) memory strengthened. Capuchin monkeys, pigeons, and humans showed similar visual-memory changes. Rhesus learned an auditory memory task and showed octave generalization for some lists of notes—tonal, but not atonal, musical passages. In contrast with visual list memory, auditory primacy memory diminished with delay and auditory recency memory strengthened. Manipulations of interitem intervals, list length, and item presentation frequency revealed proactive and retroactive inhibition among items of individual auditory lists. Repeating visual items from prior lists produced interference (on nonmatching tests) revealing how far back memory extended. The possibility of using the interference function to separate familiarity vs. recollective memory processing is discussed. PMID:18047230

Learning Efficiency: Identifying Individual Differences in Learning Rate and Retention in Healthy Adults.

PubMed

Zerr, Christopher L; Berg, Jeffrey J; Nelson, Steven M; Fishell, Andrew K; Savalia, Neil K; McDermott, Kathleen B

2018-06-01

People differ in how quickly they learn information and how long they remember it, yet individual differences in learning abilities within healthy adults have been relatively neglected. In two studies, we examined the relation between learning rate and subsequent retention using a new foreign-language paired-associates task (the learning-efficiency task), which was designed to eliminate ceiling effects that often accompany standardized tests of learning and memory in healthy adults. A key finding was that quicker learners were also more durable learners (i.e., exhibited better retention across a delay), despite studying the material for less time. Additionally, measures of learning and memory from this task were reliable in Study 1 ( N = 281) across 30 hr and Study 2 ( N = 92; follow-up n = 46) across 3 years. We conclude that people vary in how efficiently they learn, and we describe a reliable and valid method for assessing learning efficiency within healthy adults.

On the Development and Mechanics of Delayed Matching-to-Sample Performance

PubMed Central

Kangas, Brian D; Berry, Meredith S; Branch, Marc N

2011-01-01

Despite its frequent use to assess effects of environmental and pharmacological variables on short-term memory, little is known about the development of delayed matching-to-sample (DMTS) performance. This study was designed to examine the dimensions and dynamics of DMTS performance development over a long period of exposure to provide a more secure foundation for assessing stability in future research. Six pigeons were exposed to a DMTS task with variable delays for 300 sessions (i.e., 18,000 total trials; 3,600 trials per retention interval). Percent-correct and log-d measures used to quantify the development of conditional stimulus control under the procedure generally and at each of five retention intervals (0, 2, 4, 8 and 16-s) individually revealed that high levels of accuracy developed relatively quickly under the shorter retention intervals, but increases in accuracy under the longer retention intervals sometimes were not observed until 100–150 sessions had passed, with some still increasing at Session 300. Analyses of errors suggested that retention intervals induced biases by shifting control from the sample stimulus to control by position, something that was predicted by observed response biases during initial training. These results suggest that although it may require a great deal of exposure to DMTS prior to obtaining asymptotic steady state, quantification of model parameters may help predict trends when extended exposure is not feasible. PMID:21541127

Time course of scopolamine effect on memory consolidation and forgetting in rats.

PubMed

Popović, Miroljub; Giménez de Béjar, Verónica; Popović, Natalija; Caballero-Bleda, María

2015-02-01

The effect of scopolamine on the consolidation and forgetting of emotional memory has not been completely elucidated yet. The aim of the present study was to investigate the time course of scopolamine effect on consolidation and forgetting of passive avoidance response. In a first experiment of the present study, we tested the effect of scopolamine (1mg/kg, i.p., immediately after acquisition), on 24h and 48h retention performance of the step-through passive avoidance task, in adult male Wistar rats. On the 24h retested trial, the latency of the passive avoidance response was significantly lower, while on the 48h retested trial it was significantly higher in scopolamine than in the saline-treated group. In a second experiment, we assessed the 24h time course of scopolamine (1mg/kg) effect on memory consolidation in passive avoidance task. We found that scopolamine administration only within the first six and half hours after acquisition improved memory consolidation in 48h retention performance. Finally, a third experiment was performed on the saline- and scopolamine-treated rats (given immediately after acquisition) that on the 48h retention test did not step through into the dark compartment during the cut-off time. These animals were retested weekly for up to first three months, and after that, every three months until the end of experiment (i.e., 15 months after acquisition). The passive avoidance response in the saline treated group lasted up to 6 weeks after acquisition, while in the scopolamine treated group 50% of animals conserved the initial level of passive avoidance response until the experiment end point. In conclusion, the present data suggest that (1) improving or impairment effect of scopolamine given in post-training periods depends on delay of retention trial, (2) memory consolidation process could be modify by scopolamine within first six and half hours after training and (3) scopolamine could delay forgetting of emotional memory. Copyright © 2014 Elsevier Inc. All rights reserved.

A comparison of progestins within three classes: Differential effects on learning and memory in the aging surgically menopausal rat.

PubMed

Braden, B Blair; Andrews, Madeline G; Acosta, Jazmin I; Mennenga, Sarah E; Lavery, Courtney; Bimonte-Nelson, Heather A

2017-03-30

For decades, progestins have been included in hormone therapies (HT) prescribed to women to offset the risk of unopposed estrogen-induced endometrial hyperplasia. However, the potential effects on cognition of subcategories of clinically used progestins have been largely unexplored. In two studies, the present investigation evaluated the cognitive effects of norethindrone acetate (NETA), levonorgestrel (LEVO), and medroxyprogesterone acetate (MPA) on the water radial-arm maze (WRAM) and Morris water maze (MM) in middle-aged ovariectomized rats. In Study 1, six-weeks of a high-dose NETA treatment impaired learning and delayed retention on the WRAM, and impaired reference memory on the MM. Low-dose NETA treatment impaired delayed retention on the WRAM. In Study 2, high-dose NETA treatment was reduced to four-weeks and compared to MPA and LEVO. As previously shown, MPA impaired working memory performance during the lattermost portion of testing, at the highest working memory load, impaired delayed retention on the WRAM, and impaired reference memory on the MM. NETA also impaired performance on these WRAM and MM measures. Interestingly, LEVO did not impair performance, but instead enhanced learning on the WRAM. The current study corroborates previous evidence that the most commonly prescribed FDA-approved progestin for HT, MPA, impairs learning and memory in the ovariectomized middle-aged rat. When progestins from two different additional subcategories were investigated, NETA impaired learning and memory similarly to MPA, but LEVO enhanced learning. Future research is warranted to determine LEVO's potential as an ideal progestin for optimal health in women, including for cognition. Copyright © 2016 Elsevier B.V. All rights reserved.

Lateralized delay period activity marks the focus of spatial attention in working memory: evidence from somatosensory event-related brain potentials.

PubMed

Katus, Tobias; Eimer, Martin

2015-04-29

The short-term retention of sensory information in working memory (WM) is known to be associated with a sustained enhancement of neural activity. What remains controversial is whether this neural trace indicates the sustained storage of information or the allocation of attention. To evaluate the storage and attention accounts, we examined sustained tactile contralateral delay activity (tCDA component) of the event-related potential. The tCDA manifests over somatosensory cortex contralateral to task-relevant tactile information during stimulus retention. Two tactile sample sets (S1, S2) were presented sequentially, separated by 1.5 s. Each set comprised two stimuli, one per hand. Human participants memorized the location of one task-relevant stimulus per sample set and judged whether one of these locations was stimulated again at memory test. The two relevant pulses were unpredictably located on the same hand (stay trials) or on different hands (shift trials). Initially, tCDA components emerged contralateral to the relevant S1 pulse. Sequential loading of WM enhanced the tCDA after S2 was presented on stay trials. On shift trials, the tCDA's polarity reversed after S2 presentation, resulting in delay activity that was now contralateral to the task-relevant S2 pulse. The disappearance of a lateralized neural trace for the relevant S1 pulse did not impair memory accuracy for this stimulus on shift trials. These results contradict the storage account and suggest that delay period activity indicates the sustained engagement of an attention-based rehearsal mechanism. In conclusion, somatosensory delay period activity marks the current focus of attention in tactile WM. Copyright © 2015 the authors 0270-6474/15/356689-07$15.00/0.

Testing the effectiveness of cognitive interventions in alleviating accelerated long term forgetting (ALF).

PubMed

Ricci, Monica; Wong, Toh; Nikpour, Armin; Miller, Laurie A

2017-10-23

It is well established that when retrieval or other forms of testing follow shortly after the acquisition of new information, long-term memory is improved in healthy subjects (Roediger & Karpicke, 2006). It is not known whether such early interventions would alleviate ALF, a condition in which early retention is normal, but there is a steep decline over longer intervals. A different behavioral intervention (i.e., an interposed recall of a story after a longer delay) was found to prevent subsequent memory loss in a single case with ALF (Jansari, Davis, McGibbon, Firminger, & Kapur, 2010; McGibbon & Jansari, 2013), but this has yet to be replicated. In the present study, we sought to test the effectiveness of early rehearsal as well as a later interposed recall on long term memory. Three men with ALF and 10 matched, healthy males (mean age = 67 yr; mean education = 15 yr) were compared for story recall following 3 early intervention conditions. There were two early rehearsal conditions: Repeated-Recall (2 additional recalls were requested in the initial 30 min interval) and Repeated Recall With Discussion (2 additional recalls plus discussion occurred in the initial 30 min interval) as well as a Control condition, in which there was no additional rehearsal in the first 30 min. Memory for 6 stories (2 in each condition) was tested at 0 min, 30 min, 1 day, 1 week and 4 weeks. In addition, to evaluate the possible sustaining effect of an additional retrieval ("booster recall") between 1 wk and 4 wk delays, 1 story from each of the early intervention conditions was recalled at 2 weeks' delay. Consistent with the profile characteristic of ALF, nonparametric statistics revealed no group differences at 0 or 30 min recalls. For Control stories, the ALF group's recall was impaired by 24 h delay. For stories in either of the early rehearsal conditions, the patients showed better retention, performing within normal limits until the 4 week recall. The "booster recall" session at 2 weeks benefitted the patients' retention at 4 weeks, with patients' mean recall remaining within normal limits only for those stories recalled at 2 weeks. These results indicate that behavioral interventions including early rehearsal in the first several min and a booster recall at a much later time point help to prevent ALF. Confirmation of the usefulness of these interventions in other cases and investigating whether these cognitive techniques can be extended to "real world" applications are the logical next steps. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Four-hour delayed memory recall for stories: Theoretical and clinical implications of measuring accelerated long-term forgetting.

PubMed

Ladowsky-Brooks, Ricki L

2016-01-01

It has been noted that clinical neuropsychological assessment is "blind" to certain abnormalities of consolidation that occur beyond standard 30-min delay intervals. For example, normal forgetting at 30-min delays has been followed by enhanced forgetting at longer delays in temporal-lobe epilepsy, termed accelerated long-term forgetting (ALF). To evaluate whether ALF could be identified in the neuropsychological assessment of a small sample of examinees with head injuries or other neurological diagnoses (n = 42), a 4-hr delayed recall condition was added to the Logical Memory subtest of the Wechsler Memory Scale-Third Edition. A small percentage of examinees (5/42 or 11%), despite exhibiting unimpaired story recall immediately and after 30-min delays, showed increased forgetting when compared with the average retention of stories (M = 0.83, SD = 0.17) after a 4-hr delay. Three of these 5 examinees also had impaired scores on 20-min delayed recall of the California Verbal Learning Test-Second Edition (CVLT-II) and would have been identified as having memory impairment without an extended, 4-hr delayed recall. In fact, the highest correlation among memory indexes was between 4-hr delayed recall of stories and delayed recall of the CVLT-II word list (r = .59, p < .0001), suggesting different consolidation rates for relational and nonrelational material.

Ambulatory Voice Biofeedback: Relative Frequency and Summary Feedback Effects on Performance and Retention of Reduced Vocal Intensity in the Daily Lives of Participants with Normal Voices

ERIC Educational Resources Information Center

Van Stan, Jarrad H.; Mehta, Daryush D.; Sternad, Dagmar; Petit, Robert; Hillman, Robert E.

2017-01-01

Purpose: Ambulatory voice biofeedback has the potential to significantly improve voice therapy effectiveness by targeting carryover of desired behaviors outside the therapy session (i.e., retention). This study applies motor learning concepts (reduced frequency and delayed, summary feedback) that demonstrate increased retention to ambulatory voice…

Effects of Feedback Frequency and Timing on Acquisition, Retention, and Transfer of Speech Skills in Acquired Apraxia of Speech

ERIC Educational Resources Information Center

Hula, Shannon N. Austermann; Robin, Donald A.; Maas, Edwin; Ballard, Kirrie J.; Schmidt, Richard A.

2008-01-01

Purpose: Two studies examined speech skill learning in persons with apraxia of speech (AOS). Motor-learning research shows that delaying or reducing the frequency of feedback promotes retention and transfer of skills. By contrast, immediate or frequent feedback promotes temporary performance enhancement but interferes with retention and transfer.…

Rhinal and Dorsolateral Prefrontal Cortex Lesions Produce Selective Impairments in Object and Spatial Learning and Memory in Canines

PubMed Central

Christie, Lori-Ann; Saunders, Richard C.; Kowalska, Danuta, M.; MacKay, William A.; Head, Elizabeth; Cotman, Carl W.; Milgram, Norton W.

2014-01-01

To examine the effects of rhinal and dorsolateral prefrontal cortex lesions on object and spatial recognition memory in canines, we used a protocol in which both an object (delayed non-matching to sample, or DNMS) and a spatial (delayed non-matching to position or DNMP) recognition task were administered daily. The tasks used similar procedures such that only the type of stimulus information to be remembered differed. Rhinal cortex (RC) lesions produced a selective deficit on the DNMS task, both in retention of the task rules at short delays and in object recognition memory. By contrast, performance on the DNMP task remained intact at both short and long delay intervals in RC animals. Subjects who received dorsolateral prefrontal cortex (dlPFC) lesions were impaired on a spatial task at a short, 5-sec delay, suggesting disrupted retention of the general task rules, however, this impairment was transient; long-term spatial memory performance was unaffected in dlPFC subjects. The present results provide support for the involvement of the RC in object, but not visuospatial, processing and recognition memory, whereas the dlPFC appears to mediate retention of a non-matching rule. These findings support theories of functional specialization within the medial temporal lobe and frontal cortex and suggest that rhinal and dorsolateral prefrontal cortices in canines are functionally similar to analogous regions in other mammals. PMID:18792072

Support of in-flight experiments

NASA Technical Reports Server (NTRS)

Kuchnow, K. P.

1976-01-01

An outline of the various techniques used and the results obtained of attempts to achieve satisfactory preservation of ova and sperm of Fundulus heteroclitus are discussed in terms of the greatest amount of time that fertility could be retained, and also the retention of maximum fertility. Also included are the results of tests on delayed embryogenesis, should the preservation of individual gametes not prove feasible, as well as preliminary treatment of data on the orientation of ASTP juveniles.

Incidence of delayed hair re-growth, pruritus, and urinary retention after epidural anaesthesia in dogs.

PubMed

Kalchofner Guerrero, K S; Guerrero, T G; Schweizer-Kölliker, M; Ringer, S K; Hässig, M; Bettschart-Wolfensberger, R

2014-04-16

Delayed hair re-growth, pruritus and urinary retention are known complications after epidural anaesthesia in dogs. The aim of this study was to prospectively evaluate the effect of epidurally administered drugs on the occurrence of these complications in dogs. Ninety dogs were included in this study. Eighty client-owned dogs undergoing surgery were randomly assigned to one of three epidural treatment groups: either morphine and bupivacaine (MB), bupivacaine (B), or saline solution 0.9% (S) was administered epidurally to these patients. Ten dogs were only clipped in the lumbosacral area (C). Follow-up started 4 weeks after clipping and was performed every 4-5 weeks in cases of delayed hair re-growth or pruritus. Hair re-growth in the lumbosacral area was observed and compared to hair re-growth in the surgical field and the fentanyl patch area. Cytological analysis and a trichogram were performed if hair re-growth was delayed after 6 months. Time interval to first urination postoperatively was recorded (n = 80). Hair re-growth was delayed in 11 dogs (12.2%; B: n = 7, S: n = 2, MB: n = 1, C: n = 1) with no differences between groups. Pruritus was evident in two dogs (2.2%; MB: n = 1, S: n = 1). After 6 months, hair had started to re-grow in all but one dog (B). After 10 months the coat of this dog had re-grown. Time to first urination did not differ between groups. No direct correlation between the particular drugs injected epidurally and delayed hair re-growth, pruritus and urinary retention could be shown. Dog owners should be informed that hair re-growth after epidural anaesthesia could be markedly delayed.

Load-Dependent Increases in Delay-Period Alpha-Band Power Track the Gating of Task-Irrelevant Inputs to Working Memory.

PubMed

Heinz, Andrew J; Johnson, Jeffrey S

2017-01-01

Studies exploring the role of neural oscillations in cognition have revealed sustained increases in alpha-band power (ABP) during the delay period of verbal and visual working memory (VWM) tasks. There have been various proposals regarding the functional significance of such increases, including the inhibition of task-irrelevant cortical areas as well as the active retention of information in VWM. The present study examines the role of delay-period ABP in mediating the effects of interference arising from on-going visual processing during a concurrent VWM task. Specifically, we reasoned that, if set-size dependent increases in ABP represent the gating out of on-going task-irrelevant visual inputs, they should be predictive with respect to some modulation in visual evoked potentials resulting from a task-irrelevant delay period probe stimulus. In order to investigate this possibility, we recorded the electroencephalogram while subjects performed a change detection task requiring the retention of two or four novel shapes. On a portion of trials, a novel, task-irrelevant bilateral checkerboard probe was presented mid-way through the delay. Analyses focused on examining correlations between set-size dependent increases in ABP and changes in the magnitude of the P1, N1 and P3a components of the probe-evoked response and how such increases might be related to behavior. Results revealed that increased delay-period ABP was associated with changes in the amplitude of the N1 and P3a event-related potential (ERP) components, and with load-dependent changes in capacity when the probe was presented during the delay. We conclude that load-dependent increases in ABP likely play a role in supporting short-term retention by gating task-irrelevant sensory inputs and suppressing potential sources of disruptive interference.

Load-Dependent Increases in Delay-Period Alpha-Band Power Track the Gating of Task-Irrelevant Inputs to Working Memory

PubMed Central

Heinz, Andrew J.; Johnson, Jeffrey S.

2017-01-01

Studies exploring the role of neural oscillations in cognition have revealed sustained increases in alpha-band power (ABP) during the delay period of verbal and visual working memory (VWM) tasks. There have been various proposals regarding the functional significance of such increases, including the inhibition of task-irrelevant cortical areas as well as the active retention of information in VWM. The present study examines the role of delay-period ABP in mediating the effects of interference arising from on-going visual processing during a concurrent VWM task. Specifically, we reasoned that, if set-size dependent increases in ABP represent the gating out of on-going task-irrelevant visual inputs, they should be predictive with respect to some modulation in visual evoked potentials resulting from a task-irrelevant delay period probe stimulus. In order to investigate this possibility, we recorded the electroencephalogram while subjects performed a change detection task requiring the retention of two or four novel shapes. On a portion of trials, a novel, task-irrelevant bilateral checkerboard probe was presented mid-way through the delay. Analyses focused on examining correlations between set-size dependent increases in ABP and changes in the magnitude of the P1, N1 and P3a components of the probe-evoked response and how such increases might be related to behavior. Results revealed that increased delay-period ABP was associated with changes in the amplitude of the N1 and P3a event-related potential (ERP) components, and with load-dependent changes in capacity when the probe was presented during the delay. We conclude that load-dependent increases in ABP likely play a role in supporting short-term retention by gating task-irrelevant sensory inputs and suppressing potential sources of disruptive interference. PMID:28555099

Memory systems interaction in the pigeon: working and reference memory.

PubMed

Roberts, William A; Strang, Caroline; Macpherson, Krista

2015-04-01

Pigeons' performance on a working memory task, symbolic delayed matching-to-sample, was used to examine the interaction between working memory and reference memory. Reference memory was established by training pigeons to discriminate between the comparison cues used in delayed matching as S+ and S- stimuli. Delayed matching retention tests then measured accuracy when working and reference memory were congruent and incongruent. In 4 experiments, it was shown that the interaction between working and reference memory is reciprocal: Strengthening either type of memory leads to a decrease in the influence of the other type of memory. A process dissociation procedure analysis of the data from Experiment 4 showed independence of working and reference memory, and a model of working memory and reference memory interaction was shown to predict the findings reported in the 4 experiments. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Fast Mapping Across Time: Memory Processes Support Children's Retention of Learned Words.

PubMed

Vlach, Haley A; Sandhofer, Catherine M

2012-01-01

Children's remarkable ability to map linguistic labels to referents in the world is commonly called fast mapping. The current study examined children's (N = 216) and adults' (N = 54) retention of fast-mapped words over time (immediately, after a 1-week delay, and after a 1-month delay). The fast mapping literature often characterizes children's retention of words as consistently high across timescales. However, the current study demonstrates that learners forget word mappings at a rapid rate. Moreover, these patterns of forgetting parallel forgetting functions of domain-general memory processes. Memory processes are critical to children's word learning and the role of one such process, forgetting, is discussed in detail - forgetting supports extended mapping by promoting the memory and generalization of words and categories.

Role of the anterior cingulate cortex in the retrieval of novel object recognition memory after a long delay

PubMed Central

Pezze, Marie A.; Marshall, Hayley J.; Fone, Kevin CF.; Cassaday, Helen J.

2017-01-01

Previous in vivo electrophysiological studies suggest that the anterior cingulate cortex (ACgx) is an important substrate of novel object recognition (NOR) memory. However, intervention studies are needed to confirm this conclusion and permanent lesion studies cannot distinguish effects on encoding and retrieval. The interval between encoding and retrieval tests may also be a critical determinant of the role of the ACgx. The current series of experiments used micro-infusion of the GABAA receptor agonist, muscimol, into ACgx to reversibly inactivate the area and distinguish its role in encoding and retrieval. ACgx infusions of muscimol, before encoding did not alter NOR assessed after a delay of 20 min or 24 h. However, when infused into the ACgx before retrieval muscimol impaired NOR assessed after a delay of 24 h, but not after a 20-min retention test. Together these findings suggest that the ACgx plays a time-dependent role in the retrieval, but not the encoding, of NOR memory, neuronal activation being required for the retrieval of remote (24 h old), but not recent (20 min old) visual memory. PMID:28620078

Reversing the Signaled Magnitude Effect in Delayed Matching to Sample: Delay-Specific Remembering?

ERIC Educational Resources Information Center

White, K. Geoffrey; Brown, Glenn S.

2011-01-01

Pigeons performed a delayed matching-to-sample task in which large or small reinforcers for correct remembering were signaled during the retention interval. Accuracy was low when small reinforcers were signaled, and high when large reinforcers were signaled (the signaled magnitude effect). When the reinforcer-size cue was switched from small to…

Involvement of hippocampal NMDA receptors in encoding and consolidation, but not retrieval, processes of spontaneous object location memory in rats.

PubMed

Yamada, Kazuo; Arai, Misaki; Suenaga, Toshiko; Ichitani, Yukio

2017-07-28

The hippocampus is thought to be involved in object location recognition memory, yet the contribution of hippocampal NMDA receptors to the memory processes, such as encoding, retention and retrieval, is unknown. First, we confirmed that hippocampal infusion of a competitive NMDA receptor antagonist, AP5 (2-amino-5-phosphonopentanoic acid, 20-40nmol), impaired performance of spontaneous object location recognition test but not that of novel object recognition test in Wistar rats. Next, the effects of hippocampal AP5 treatment on each process of object location recognition memory were examined with three different injection times using a 120min delay-interposed test: 15min before the sample phase (Time I), immediately after the sample phase (Time II), and 15min before the test phase (Time III). The blockade of hippocampal NMDA receptors before and immediately after the sample phase, but not before the test phase, markedly impaired performance of object location recognition test, suggesting that hippocampal NMDA receptors play an important role in encoding and consolidation/retention, but not retrieval, of spontaneous object location memory. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhanced 99 Tc retention in glass waste form using Tc(IV)-incorporated Fe minerals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Um, Wooyong; Luksic, Steven A.; Wang, Guohui

Technetium (99Tc) immobilization by doping into iron oxide mineral phases may alleviate the problems with Tc volatility during vitrification of nuclear waste. Reduced Tc, Tc(IV), substitutes for Fe(III) in the crystal structure by a process of Tc reduction from Tc(VII) to Tc(IV) followed by co-precipitation of Fe oxide minerals. Two Tc-incorporated Fe minerals (Tc-goethite and Tc-magnetite/maghemite) were prepared and tested for Tc retention in glass melt samples at temperatures between 600 – 1,000 oC. After being cooled, the solid glass specimens prepared at different temperatures were analyzed for Tc oxidation state using Tc K-edge XANES. In most samples, Tc wasmore » partially oxidized from Tc(IV) to Tc(VII) as the melt temperature increased. However, Tc retention in glass melt samples prepared using Tc-incorporated Fe minerals were moderately higher than in glass prepared using KTcO4 because of limited and delayed Tc volatilization.« less

Walking through doorways causes forgetting: Event structure or updating disruption?

PubMed

Pettijohn, Kyle A; Radvansky, Gabriel A

2016-11-01

According to event cognition theory, people segment experience into separate event models. One consequence of this segmentation is that when people transport objects from one location to another, memory is worse than if people move across a large location. In two experiments participants navigated through a virtual environment, and recognition memory was tested in either the presence or the absence of a location shift for objects that were recently interacted with (i.e., just picked up or set down). Of particular concern here is whether this location updating effect is due to (a) differences in retention intervals as a result of the navigation process, (b) a temporary disruption in cognitive processing that may occur as a result of the updating processes, or (c) a need to manage multiple event models, as has been suggested in prior research. Experiment 1 explored whether retention interval is driving this effect by recording travel times from the acquisition of an object and the probe time. The results revealed that travel times were similar, thereby rejecting a retention interval explanation. Experiment 2 explored whether a temporary disruption in processing is producing the effect by introducing a 3-second delay prior to the presentation of a memory probe. The pattern of results was not affected by adding a delay, thereby rejecting a temporary disruption account. These results are interpreted in the context of the event horizon model, which suggests that when there are multiple event models that contain common elements there is interference at retrieval, which compromises performance.

Hot water bath treatments assisted by microwave energy to delay postharvest ripening and decay in strawberries (Fragaria × ananassa).

PubMed

Villa-Rojas, Rossana; López-Malo, Aurelio; Sosa-Morales, María Elena

2011-09-01

A lab-scale approach using microwave (MW)-assisted hot water treatments was developed and tested to assess the potential of this heating method to delay postharvest ripening and decay in strawberries. Strawberries (Fragaria × ananassa) immersed in water were exposed to microwaves at a frequency of 2450 MHz for 3 min at 514 W or 1 min 50 s at 763 W to reach an average temperature of 43.8 ± 0.6 °C at the fruit centre. Another batch was treated in hot water at 45 °C for 15 min, and a final batch was not treated (control). After 9 days of refrigerated storage (3 °C and 90% relative humidity), all heat-treated strawberries showed significant retention of quality parameters such as colour and firmness and significantly lower yeast and mould populations (P < 0.05). Strawberries subjected to MW-assisted hot water treatments showed significantly better retention of lightness compared with conventionally treated berries. A short (1 min 50 s) treatment at 763 W was the best choice to prevent strawberry decay. Copyright © 2011 Society of Chemical Industry.

Timing matters: negative emotion elicited 5 min but not 30 min or 45 min after learning enhances consolidation of internal-monitoring source memory.

PubMed

Wang, Bo; Bukuan, Sun

2015-05-01

Two experiments examined the time-dependent effects of negative emotion on consolidation of item and internal-monitoring source memory. In Experiment 1, participants (n=121) learned a list of words. They were asked to read aloud half of the words and to think about the remaining half. They were instructed to memorize each word and its associative cognitive operation ("reading" versus "thinking"). Immediately following learning they conducted free recall and then watched a 3-min either neutral or negative video clip when 5 min, 30 min or 45 min had elapsed after learning. Twenty-four hours later they returned to take surprise tests for item and source memory. Experiment 2 was similar to Experiment 1 except that participants, without conducting an immediate test of free recall, took tests of source memory for all encoded words both immediately and 24 h after learning. Experiment 1 showed that negative emotion enhanced consolidation of item memory (as measured by retention ratio of free recall) regardless of delay of emotion elicitation and that negative emotion enhanced consolidation of source memory when it was elicited at a 5 min delay but reduced consolidation of source memory when it was elicited at a 30 min delay; when elicited at a 45 min delay, negative emotion had little effect. Furthermore, Experiment 2 replicated the enhancement effect on source memory in the 5 min delay even when participants were tested on all the encoded words. The current study partially replicated prior studies on item memory and extends the literature by providing evidence for a time-dependent effect of negative emotion on consolidation of source memory based on internal monitoring. Copyright © 2015 Elsevier B.V. All rights reserved.

Artistic drawing as a mnemonic device

NASA Astrophysics Data System (ADS)

Baker Christensen, Leslie

Despite art-based learning being widely used, existing data are primarily qualitative, and most research has not isolated particular variables such as memory for empirical study. The few experiments that have been conducted demonstrated that drawing improves free recall of unpaired words, and retention improves after lessons integrated with drawing, drama, and narrative exercises. To help fill the gap in the current literature, the present study compared the effectiveness of encoding and the rate of memory decay between a drawing mnemonic and note taking on a paired associates task. Using a within-subjects experimental design, participants were presented with word pairs and asked to complete either a drawing mnemonic (DM) or note taking (NT) to assist memorization. Participants were tested immediately after the word pair presentation and after a 20-minute delay. Results supported the hypothesis that the DM condition would produce superior encoding, as evidenced by greater retention on the immediate test. However, no memory decay was observed in the experiment, and therefore results on the delayed test were inconclusive. In fact, scores for the NT condition improved over time whereas the scores for the DM condition did not, which might imply that note taking results in a different consolidation process than drawing. Findings from this study suggested that arts integration can be an effective method to support memory for learned information. Future studies that examine the effect of rehearsal and the long-term effectiveness of a drawing mnemonic are warranted. This dissertation is available in open access at AURA, http://aura.antioch.edu/ and Ohio Link ETD Center, https://etd.ohiolink.edu/etd.

Balance maintenance as an acquired motor skill: Delayed gains and robust retention after a single session of training in a virtual environment.

PubMed

Elion, Orit; Sela, Itamar; Bahat, Yotam; Siev-Ner, Itzhak; Weiss, Patrice L Tamar; Karni, Avi

2015-06-03

Does the learning of a balance and stability skill exhibit time-course phases and transfer limitations characteristic of the acquisition and consolidation of voluntary movement sequences? Here we followed the performance of young adults trained in maintaining balance while standing on a moving platform synchronized with a virtual reality road travel scene. The training protocol included eight 3 min long iterations of the road scene. Center of Pressure (CoP) displacements were analyzed for each task iteration within the training session, as well as during tests at 24h, 4 weeks and 12 weeks post-training to test for consolidation phase ("offline") gains and assess retention. In addition, CoP displacements in reaction to external perturbations were assessed before and after the training session and in the 3 subsequent post-training assessments (stability tests). There were significant reductions in CoP displacements as experience accumulated within session, with performance stabilizing by the end of the session. However, CoP displacements were further reduced at 24h post-training (delayed "offline" gains) and these gains were robustly retained. There was no transfer of the practice-related gains to performance in the stability tests. The time-course of learning the balance maintenance task, as well as the limitation on generalizing the gains to untrained conditions, are in line with the results of studies of manual movement skill learning. The current results support the conjecture that a similar repertoire of basic neuronal mechanisms of plasticity may underlay skill (procedural, "how to" knowledge) acquisition and skill memory consolidation in voluntary and balance maintenance tasks. Copyright © 2015 Elsevier B.V. All rights reserved.

Get the gist? The effects of processing depth on false recognition in short-term and long-term memory.

PubMed

Flegal, Kristin E; Reuter-Lorenz, Patricia A

2014-07-01

Gist-based processing has been proposed to account for robust false memories in the converging-associates task. The deep-encoding processes known to enhance verbatim memory also strengthen gist memory and increase distortions of long-term memory (LTM). Recent research has demonstrated that compelling false memory illusions are relatively delay-invariant, also occurring under canonical short-term memory (STM) conditions. To investigate the contributions of gist to false memory at short and long delays, processing depth was manipulated as participants encoded lists of four semantically related words and were probed immediately, following a filled 3- to 4-s retention interval, or approximately 20 min later, in a surprise recognition test. In two experiments, the encoding manipulation dissociated STM and LTM on the frequency, but not the phenomenology, of false memory. Deep encoding at STM increases false recognition rates at LTM, but confidence ratings and remember/know judgments are similar across delays and do not differ as a function of processing depth. These results suggest that some shared and some unique processes underlie false memory illusions at short and long delays.

A Look into Students' Retention of Acquired Nature of Science Understandings

NASA Astrophysics Data System (ADS)

Khishfe, Rola

2015-07-01

Having the learning and retention of science content and skills as a goal of scientific literacy, it is significant to study the issue of retention as it relates to teaching and learning about nature of science (NOS). Then, the purpose of this study was to investigate the development of NOS understandings of students, and the retention of these understandings four months after being acquired through explicit reflective instruction in relation to two contexts. Participants were 24 tenth-grade students at a private high school in a city in the Middle East. Explicit NOS instruction was addressed within a six-week unit about genetic engineering. Three NOS aspects were integrated and dispersed across the unit. A questionnaire, together with semi-structured interviews, was administered as pre-, post-, and delayed post-test to assess the retention of participants' NOS understandings. The questionnaire had two open-ended scenarios addressing controversial socioscientific issues about genetically modified food and water fluoridation. Results showed that most students improved their naïve understandings of NOS in relation to the two contexts following the six-week unit with the explicit NOS instruction. However, these newly acquired NOS understandings were not retained by all students four months after instruction. Many of the students reverted back to their earlier naïve understandings. Conclusions about the factors facilitating the process of retention as the orientation to meaningful learning and the prolonged exposure to the domain were discussed in relation to practical implications in the classroom.

Effects of social instability stress in adolescence on long-term, not short-term, spatial memory performance.

PubMed

Green, Matthew R; McCormick, Cheryl M

2013-11-01

There is evidence that exposure to stressors in adolescence leads to lasting deficits on hippocampal-dependent tasks, but whether medial prefrontal cortical function is also impaired is unknown. We previously found that rats exposed to social instability stress in adolescence (SS; daily 1h isolation and subsequent change of cage partner between postnatal days 30 and 45) had impaired memory performance on a Spatial Object Location test and in memory for fear conditioning context, tasks that depend on the integrity of the hippocampus. Here we investigated whether impaired performance would be evident after adolescent SS in male rats on a different test of hippocampal function, spatial learning and memory in the Morris water maze (MWM) and on a working memory task for which performance depends on the integrity of the medial prefrontal cortex, the Delayed Alternation task (DAT). During MWM testing, SS rats showed greater improvements in performance across trials within days compared to control (CTL) rats, but showed less retention of learning between days (48 h) compared to CTL rats. Similarly, SS rats had impaired long-term memory in the Spatial Object Location test after a long delay (240 min), but not after shorter delays (15 or 60 min) compared to CTL rats. No group differences were observed on the DAT, which assessed working memory across brief delays (5-90 s). Thus, deficits in memory performance after chronic social stress in adolescence may be limited to long-term memory. Copyright © 2013 Elsevier B.V. All rights reserved.

Retrieval practice is an efficient method of enhancing the retention of anatomy and physiology information.

PubMed

Dobson, John L

2013-06-01

Although a great deal of empirical evidence has indicated that retrieval practice is an effective means of promoting learning and memory, very few studies have investigated the strategy in the context of an actual class. The primary purpose of this study was to determine if a series of very brief retrieval quizzes could significantly improve the retention of previously tested information throughout an anatomy and physiology course. A second purpose was to determine if there were any significant differences between expanding and uniform patterns of retrieval that followed a standardized initial retrieval delay. Anatomy and physiology students were assigned to either a control group or groups that were repeatedly prompted to retrieve a subset of previously tested course information via a series of quizzes that were administered on either an expanding or a uniform schedule. Each retrieval group completed a total of 10 retrieval quizzes, and the series of quizzes required (only) a total of 2 h to complete. Final retention of the exam subset material was assessed during the last week of the semester. There were no significant differences between the expanding and uniform retrieval groups, but both retained an average of 41% more of the subset material than did the control group (ANOVA, F = 129.8, P = 0.00, ηp(2) = 0.36). In conclusion, retrieval practice is a highly efficient and effective strategy for enhancing the retention of anatomy and physiology material.

Achilles' ear? Inferior human short-term and recognition memory in the auditory modality.

PubMed

Bigelow, James; Poremba, Amy

2014-01-01

Studies of the memory capabilities of nonhuman primates have consistently revealed a relative weakness for auditory compared to visual or tactile stimuli: extensive training is required to learn auditory memory tasks, and subjects are only capable of retaining acoustic information for a brief period of time. Whether a parallel deficit exists in human auditory memory remains an outstanding question. In the current study, a short-term memory paradigm was used to test human subjects' retention of simple auditory, visual, and tactile stimuli that were carefully equated in terms of discriminability, stimulus exposure time, and temporal dynamics. Mean accuracy did not differ significantly among sensory modalities at very short retention intervals (1-4 s). However, at longer retention intervals (8-32 s), accuracy for auditory stimuli fell substantially below that observed for visual and tactile stimuli. In the interest of extending the ecological validity of these findings, a second experiment tested recognition memory for complex, naturalistic stimuli that would likely be encountered in everyday life. Subjects were able to identify all stimuli when retention was not required, however, recognition accuracy following a delay period was again inferior for auditory compared to visual and tactile stimuli. Thus, the outcomes of both experiments provide a human parallel to the pattern of results observed in nonhuman primates. The results are interpreted in light of neuropsychological data from nonhuman primates, which suggest a difference in the degree to which auditory, visual, and tactile memory are mediated by the perirhinal and entorhinal cortices.

Neurogenic bladder from occult herpes zoster.

PubMed

Rothrock, J F; Walicke, P A; Swenson, M R

1986-11-01

Active infection with herpes zoster may cause acute urinary retention, especially when it involves sacral dermatomes. Although frank retention usually develops days to weeks after eruption of the typical rash, bladder incompetence infrequently develops first, raising concern over other, more ominous etiologies. In the case presented, rash appearance was delayed until six weeks after the initial onset of urinary retention, a much longer interval than previously reported. Occult herpes zoster infection should be considered in patients presenting with an acute neurogenic bladder of obscure cause.

Inference and analysis of xenon outflow curves under multi-pulse injection in two-dimensional chromatography.

PubMed

Shu-Jiang, Liu; Zhan-Ying, Chen; Yin-Zhong, Chang; Shi-Lian, Wang; Qi, Li; Yuan-Qing, Fan

2013-10-11

Multidimensional gas chromatography is widely applied to atmospheric xenon monitoring for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). To improve the capability for xenon sampling from the atmosphere, sampling techniques have been investigated in detail. The sampling techniques are designed by xenon outflow curves which are influenced by many factors, and the injecting condition is one of the key factors that could influence the xenon outflow curves. In this paper, the xenon outflow curves of single-pulse injection in two-dimensional gas chromatography has been tested and fitted as a function of exponential modified Gaussian distribution. An inference formula of the xenon outflow curve for six-pulse injection is derived, and the inference formula is also tested to compare with its fitting formula of the xenon outflow curve. As a result, the curves of both the one-pulse and six-pulse injections obey the exponential modified Gaussian distribution when the temperature of the activated carbon column's temperature is 26°C and the flow rate of the carrier gas is 35.6mLmin(-1). The retention time of the xenon peak for one-pulse injection is 215min, and the peak width is 138min. For the six-pulse injection, however, the retention time is delayed to 255min, and the peak width broadens to 222min. According to the inferred formula of the xenon outflow curve for the six-pulse injection, the inferred retention time is 243min, the relative deviation of the retention time is 4.7%, and the inferred peak width is 225min, with a relative deviation of 1.3%. Copyright © 2013 Elsevier B.V. All rights reserved.

Are two heads better than one? Comparing dyad and self-regulated learning in simulation training.

PubMed

Shanks, David; Brydges, Ryan; den Brok, Wendie; Nair, Parvathy; Hatala, Rose

2013-12-01

The optimal learner to simulator ratio for procedural skills training is not known. Research in motor learning suggests observational training in pairs, termed 'dyad training', may be as effective as directed self-regulated learning (DSRL). This study was conducted to compare the relative effectiveness and efficiency of dyad versus DSRL training of simulation-based lumbar puncture (LP). We conducted a two-group randomised equivalence trial. First-year internal medicine residents (n = 50) were randomly assigned to learn LP either in dyads or as individual learners on a simulator, using a directed self-regulated approach (i.e. the learning sequence was defined for them, but they defined the pace of learning). Participants were videotaped performing a simulated LP on a pre-test, an immediate post-test, and a 6-week delayed retention test. In duplicate, blinded raters independently evaluated all trainee performances using a previously validated 5-point global rating scale (GRS) and 35-item checklist. Our analyses showed no significant differences (p = 0.69) on pre-test, post-test or retention test GRS scores between the dyad (mean ± standard deviation [SD] scores by test: 2.39 ± 0.57, 3.48 ± 0.62, 3.12 ± 0.85, respectively) and DSRL (mean ± SD scores by test: 2.67 ± 0.50, 3.34 ± 0.77, 3.21 ± 0.79, respectively) groups. Both groups improved significantly from pre-test to post-test (p < 0.001) and retained that performance following the 6-week delay. Dyad participants experienced significantly greater pre-test to post-test gains than DSRL participants (p = 0.02). There was no significant difference in total practice time between the groups (20.94 minutes for individuals and 24.20 minutes for dyads; p = 0.175). Our results indicate that learning in pairs is as effective as independent DSRL. Dyad training permits the more efficient use of simulators as two learners use the same resources as an individual. © 2013 John Wiley & Sons Ltd.

Adolescent Learning in the Zoo: Embedding a Non-Formal Learning Environment to Teach Formal Aspects of Vertebrate Biology

NASA Astrophysics Data System (ADS)

Randler, Christoph; Kummer, Barbara; Wilhelm, Christian

2012-06-01

The aim of this study was to assess the outcome of a zoo visit in terms of learning and retention of knowledge concerning the adaptations and behavior of vertebrate species. Basis of the work was the concept of implementing zoo visits as an out-of-school setting for formal, curriculum based learning. Our theoretical framework centers on the self-determination theory, therefore, we used a group-based, hands-on learning environment. To address this questions, we used a treatment—control design (BACI) with different treatments and a control group. Pre-, post- and retention tests were applied. All treatments led to a substantial increase of learning and retention knowledge compared to the control group. Immediately after the zoo visit, the zoo-guide tour provided the highest scores, while after a delay of 6 weeks, the learner-centered environment combined with a teacher-guided summarizing scored best. We suggest incorporating the zoo as an out-of-school environment into formal school learning, and we propose different methods to improve learning in zoo settings.

The Effects of Hypertext Gloss on Comprehension and Vocabulary Retention under Incidental and Intentional Learning Conditions

ERIC Educational Resources Information Center

Zandieh, Zeinab; Jafarigohar, Manoochehr

2012-01-01

The present study investigated comprehension, immediate and delayed vocabulary retention under incidental and intentional learning conditions via computer mediated hypertext gloss. One hundred and eighty four (N = 184) intermediate students of English as a foreign language at an English school participated in the study. They were randomly assigned…

Feather retention force in broiler carcasses slaughtered and held up to 8 hours postmortem prior to scalding

USDA-ARS?s Scientific Manuscript database

One factor that could impact the feasibility of commercial on-farm slaughter of broilers is the time delay from on-farm slaughter to scalding and defeathering in the commercial plant that could be 4 h or more. This experiment evaluated feather retention force (FRF) in broilers that were slaughtered ...

Reversing the Course of Forgetting

PubMed Central

White, K. Geoffrey; Brown, Glenn S

2011-01-01

Forgetting functions were generated for pigeons in a delayed matching-to-sample task, in which accuracy decreased with increasing retention-interval duration. In baseline training with dark retention intervals, accuracy was high overall. Illumination of the experimental chamber by a houselight during the retention interval impaired performance accuracy by increasing the rate of forgetting. In novel conditions, the houselight was lit at the beginning of a retention interval and then turned off partway through the retention interval. Accuracy was low at the beginning of the retention interval and then increased later in the interval. Thus the course of forgetting was reversed. Such a dissociation of forgetting from the passage of time is consistent with an interference account in which attention or stimulus control switches between the remembering task and extraneous events. PMID:21909163

Sleep can reduce the testing effect: it enhances recall of restudied items but can leave recall of retrieved items unaffected.

PubMed

Bäuml, Karl-Heinz T; Holterman, Christoph; Abel, Magdalena

2014-11-01

The testing effect refers to the finding that retrieval practice in comparison to restudy of previously encoded contents can improve memory performance and reduce time-dependent forgetting. Naturally, long retention intervals include both wake and sleep delay, which can influence memory contents differently. In fact, sleep immediately after encoding can induce a mnemonic benefit, stabilizing and strengthening the encoded contents. We investigated in a series of 5 experiments whether sleep influences the testing effect. After initial study of categorized item material (Experiments 1, 2, and 4A), paired associates (Experiment 3), or educational text material (Experiment 4B), subjects were asked to restudy encoded contents or engage in active retrieval practice. A final recall test was conducted after a 12-hr delay that included diurnal wakefulness or nocturnal sleep. The results consistently showed typical testing effects after the wake delay. However, these testing effects were reduced or even eliminated after sleep, because sleep benefited recall of restudied items but left recall of retrieved items unaffected. The findings are consistent with the bifurcation model of the testing effect (Kornell, Bjork, & Garcia, 2011), according to which the distribution of memory strengths across items is shifted differentially by retrieving and restudying, with retrieval strengthening items to a much higher degree than restudy does. On the basis of this model, most of the retrieved items already fall above recall threshold in the absence of sleep, so additional sleep-induced strengthening may not improve recall of retrieved items any further. PsycINFO Database Record (c) 2014 APA, all rights reserved.

More Feedback Is Better than Less: Learning a Novel Upper Limb Joint Coordination Pattern with Augmented Auditory Feedback

PubMed Central

Fujii, Shinya; Lulic, Tea; Chen, Joyce L.

2016-01-01

Motor learning is a process whereby the acquisition of new skills occurs with practice, and can be influenced by the provision of feedback. An important question is what frequency of feedback facilitates motor learning. The guidance hypothesis assumes that the provision of less augmented feedback is better than more because a learner can use his/her own inherent feedback. However, it is unclear whether this hypothesis holds true for all types of augmented feedback, including for example sonified information about performance. Thus, we aimed to test what frequency of augmented sonified feedback facilitates the motor learning of a novel joint coordination pattern. Twenty healthy volunteers first reached to a target with their arm (baseline phase). We manipulated this baseline kinematic data for each individual to create a novel target joint coordination pattern. Participants then practiced to learn the novel target joint coordination pattern, receiving either feedback on every trial i.e., 100% feedback (n = 10), or every other trial, i.e., 50% feedback (n = 10; acquisition phase). We created a sonification system to provide the feedback. This feedback was a pure tone that varied in intensity in proportion to the error of the performed joint coordination relative to the target pattern. Thus, the auditory feedback contained information about performance in real-time (i.e., “concurrent, knowledge of performance feedback”). Participants performed the novel joint coordination pattern with no-feedback immediately after the acquisition phase (immediate retention phase), and on the next day (delayed retention phase). The root-mean squared error (RMSE) and variable error (VE) of joint coordination were significantly reduced during the acquisition phase in both 100 and 50% feedback groups. There was no significant difference in VE between the groups at immediate and delayed retention phases. However, at both these retention phases, the 100% feedback group showed significantly smaller RMSE than the 50% group. Thus, contrary to the guidance hypothesis, our findings suggest that the provision of more, concurrent knowledge of performance auditory feedback during the acquisition of a novel joint coordination pattern, may result in better skill retention. PMID:27375414

Dopamine antagonists during parturition disrupt maternal care and the retention of maternal behavior in rats.

PubMed

Byrnes, Elizabeth M; Rigero, Beth A; Bridges, Robert S

2002-11-01

Brief contact with pups at parturition enables the female rat to establish and retain the full repertoire of maternal behaviors, allowing her to respond rapidly to pups in the future. To determine whether the dopamine system is involved in the retention of maternal behavior, females were continuously infused with dopamine antagonists during the periparturitional period and then allowed either a brief interaction period with pups (3 h) or no interaction with pups (pups removed as they were born). Females were exposed to either the D1-like antagonist SCH 23390 (0.1 or 1.0 mg/kg/day) or the D2-like antagonist clebopride (0.5 or 1.0 mg/kg/day). The high dose of either DA antagonist resulted in significant attenuation of maternal care immediately postpartum. When tested for the retention of maternal behavior 7 days later, however, only the females exposed to the D2 antagonist displayed a delayed response to shown full maternal behavior (FMB) towards donor pups. Thus, while both dopamine receptor subtypes appear necessary for the full and rapid expression of maternal behavior during the early postpartum period, only the D2 receptor subtype appears to be involved in the retention of this behavior.

Longitudinal and reciprocal relations between delay discounting and crime

PubMed Central

Lee, Christine A.; Derefinko, Karen J.; Milich, Richard; Lynam, Donald R.; DeWall, C. Nathan

2017-01-01

Theorists argue that self-control failure is the underlying cause of criminal behavior, with previous research linking poor self-control to delinquency and drug use. The path from self-control to crime is well-established, but less is known about whether criminal behavior contributes to self-control deficits over time. We investigated bi-directional relations between self-control assessed via a delay discounting task and self-reported crime over a three-year period. During their first, second (73.38% retention rate), and third (63.12% retention rate) years of college, 526 undergraduates completed a delay discounting task and reported on their criminal behavior. In order to maximize variability, participants with conduct problems were overrecruited, comprising 23.1% of the final sample. As expected, more discounting of hypothetical monetary rewards significantly predicted future property crime across a one and two-year period, even when controlling for initial levels of both. This study also demonstrated evidence of a bi-directional relationship; violent crime predicted higher rates of delay discounting one year later. These results suggest that bi-directional relations exist between self-control and types of crime. PMID:28970645

Right recumbent position on gastric emptying of water evidenced by 13C breath testing

PubMed Central

Sanaka, Masaki; Urita, Yoshihisa; Yamamoto, Takatsugu; Shirai, Tsuguru; Kimura, Satoshi; Aoyagi, Hitoshi; Kuyama, Yasushi

2013-01-01

AIM: To compare the impact of the right recumbent position with the sitting position on gastric emptying of water. METHODS: In eight healthy male volunteers, the 13C acetate breath test was performed twice to assess gastric emptying of 100 mL tap water. Subjects were seated in one test and lying on their right side in the other. In both positions, pulmonary 13CO2 exhalation curves were obtained by plotting breath data against time. Percent gastric retention curves were created by analyzing data using the Wagner-Nelson protocol. RESULTS: No significant posture effect was found in pulmonary 13CO2 output curves (P = 0.2150), whereas a significant effect was seen in gastric retention curves (P = 0.0315). The percent retention values at 10 min and 15 min were significantly smaller when subjects were in the right recumbent position compared with the seated position (P < 0.05). Our results verified the accelerating effect of the right recumbent position on gastric emptying of non-nutritive solutions. Concerning clinical implications, this study suggests that placing patients with acute pain on their right side after oral administration of analgesic drugs in solution is justified as an effective practice for rapid pain relief. For patients with gastrointestinal reflux symptoms, sleeping in the right recumbent position may reduce nocturnal symptoms, as delayed gastric emptying can cause reflux symptoms. CONCLUSION: Gastric emptying of water occurs more quickly when a subject lies on the right side compared with sitting. PMID:23372358

Effects of environmental and pharmacological manipulations on a novel delayed nonmatching-to-sample 'working memory' procedure in unrestrained rhesus monkeys.

PubMed

Hutsell, Blake A; Banks, Matthew L

2015-08-15

Working memory is a domain of 'executive function.' Delayed nonmatching-to-sample (DNMTS) procedures are commonly used to examine working memory in both human laboratory and preclinical studies. The aim was to develop an automated DNMTS procedure maintained by food pellets in rhesus monkeys using a touch-sensitive screen attached to the housing chamber. Specifically, the DNMTS procedure was a 2-stimulus, 2-choice recognition memory task employing unidimensional discriminative stimuli and randomized delay interval presentations. DNMTS maintained a delay-dependent decrease in discriminability that was independent of the retention interval distribution. Eliminating reinforcer availability during a single delay session or providing food pellets before the session did not systematically alter accuracy, but did reduce total choices. Increasing the intertrial interval enhanced accuracy at short delays. Acute Δ(9)-THC pretreatment produced delay interval-dependent changes in the forgetting function at doses that did not alter total choices. Acute methylphenidate pretreatment only decreased total choices. All monkeys were trained to perform NMTS at the 1s training delay within 60 days of initiating operant touch training. Furthermore, forgetting functions were reliably delay interval-dependent and stable over the experimental period (∼6 months). Consistent with previous studies, increasing the intertrial interval improved DNMTS performance, whereas Δ(9)-THC disrupted DNMTS performance independent of changes in total choices. Overall, the touchscreen-based DNMTS procedure described provides an efficient method for training and testing experimental manipulations on working memory in unrestrained rhesus monkeys. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of Intermittent Reinforcement on Acquisition and Retention in Delayed Matching-to-Sample in Pigeons

ERIC Educational Resources Information Center

Grant, Douglas S.

2011-01-01

Experiments 1 and 2 involved independent groups that received primary reinforcement after a correct match with a probability of 1.0, 0.50 or 0.25. Correct matches that did not produce primary reinforcement produced a conditioned reinforcer. Both experiments revealed little evidence that acquisition or retention was adversely affected by use of…

Effects of angle of model-demonstration on learning of motor skill.

PubMed

Ishikura, T; Inomata, K

1995-04-01

The purpose was to examine the effects of three different demonstrations by a model on acquisition and retention of a sequential gross movement task. The second purpose was to examine the relationship between reversal processing of visual information about skills and coding of skill information. Thirty undergraduates (15 men and 15 women) were assigned into one of three conditions, Objective condition which demonstrated the task with the model facing the subject. Looking-glass condition in which the skill was demonstrated with the model facing the subject who viewed the performance opposite the right and left directions in executing the task, and the Subjective condition in which the subject observed the model from the rear. Number of immediate recall tests required to accomplish the sequential movements completely and the sum of the performance points for reproduced movements at each delayed recall test (1 day, 7 days, and 5 mo. after the immediate recall test) were employed. Analysis indicated the Subjective condition produced a significantly greater modeling effect in immediate recall of the movements than the Looking-glass condition. Retention of the acquired skills was almost equal under the three conditions.

Assessment of Gastric Emptying in Patients with Autoimmune Gastritis.

PubMed

Kalkan, Çağdaş; Soykan, Irfan; Soydal, Çiğdem; Özkan, Elgin; Kalkan, Emra

2016-06-01

Symptoms of patients with autoimmune gastritis are not specific, and some patients may present symptoms suggestive of delayed gastric emptying. This study aims to investigate whether any delay in gastric emptying of solid food exists in patients with autoimmune gastritis and, if so, to identify the factors that might affect delayed gastric emptying. A total of 165 patients (106 women) diagnosed as having autoimmune gastritis were analyzed by means of a gastric emptying test. All patients underwent a standardized scintigraphic gastric emptying study. Patients with delayed gastric emptying and normal gastric emptying tests were then compared by means of factors that might affect gastric emptying. Also 65 patients with functional dyspepsia who had a gastric emptying study constituted the control group. The median gastric emptying T ½ time was 127.43 min (min-max 50-953) for patients with AIG and 81 min (min-max 21-121.6) for functional dyspepsia patients (p < 0.001), and median percent retention at 2 h was 63.8 versus 20.2 (p < 0.001). In multivariate analysis, parameters that affected gastric emptying T ½ time were found as serum gastrin level (OR 1.002, 95 % CI 1.001-1.004, p < 0.001, chronic inflammation (OR 3.689, 95 % CI 1.44-9.39, p < 0.001), and increase in the degree of the atrophy of the gastric mucosa (OR 8.96, 95 % CI 2.98-26.93, p < 0.001). In patients with autoimmune gastritis, gastric emptying is generally delayed. Autoimmune gastritis is an important etiology to explain the finding of delayed gastric emptying on a radionuclide test. This new finding is likely to be relevant to clinicians when evaluating and initiating appropriate medical treatment for patients with autoimmune gastritis manifesting upper gastrointestinal symptoms.

Endoscopic submucosal dissection for early gastric cancer on the lesser curvature in upper third of the stomach is a risk factor for postoperative delayed gastric emptying.

PubMed

Yoshizaki, Tetsuya; Obata, Daisuke; Aoki, Yasuhiro; Okamoto, Norihiro; Hashimura, Hiroki; Kano, Chise; Matsushita, Megumi; Kanamori, Atsushi; Matsumoto, Kei; Tsujimae, Masahiro; Momose, Kenji; Eguchi, Takaaki; Okuyama, Shunsuke; Yamashita, Hiroshi; Fujita, Mikio; Okada, Akihiko

2018-02-07

Advances in Endoscopic submucosal dissection (ESD) technology have established ESD for early gastric cancer as a safe and stable technique. However, ESD may induce delayed gastric emptying and the cause of food residue retention in the stomach after ESD is not clear. This study aimed to clarify risk factors for delayed gastric emptying with food retention after gastric ESD. We retrospectively examined for food residue in the stomach 1 week after ESD was performed for early gastric carcinoma at Osaka Saiseikai Nakatsu Hospital from February 2008 to November 2016. Food residue was observed in 68 (6.1%) of 1114 patients who underwent gastric ESD. The percentage of lesions located on the lesser curvature of the upper third of the stomach was 45.6% (31/68) in the food residue group and 3.5% (37/1046) in the non-food residue group, which was significantly different (P < 0.01). Multivariate logistic regression analysis revealed that lesions on the lesser curvature of the upper third of the stomach (Odds ratio [OR] 23.31, 95% confidence interval [CI] 12.60-43.61, P < 0.01), post-ESD bleeding (OR 4.25, 95%CI 1.67-9.80, P < 0.01), submucosal invasion (OR 2.80, 95%CI 1.34-5.63, P < 0.01), and age over 80 years (OR 2.34, 95%CI 1.28-4.22, P < 0.01) were independent risk factors for food retention after gastric ESD. Of the 68 patients, 3 had food residue in the stomach on endoscopic examination for follow-up observation after the ESD ulcer had healed. Delayed gastric emptying with food retention after gastric ESD was associated with lesions located in the lesser curvature of the upper stomach, submucosal invasion of the lesion, age older than 80 years, and post-ESD bleeding, though it was temporary in most cases.

Learning-performance distinction and memory processes for motor skills: a focused review and perspective.

PubMed

Kantak, Shailesh S; Winstein, Carolee J

2012-03-01

Behavioral research in cognitive psychology provides evidence for an important distinction between immediate performance that accompanies practice and long-term performance that reflects the relative permanence in the capability for the practiced skill (i.e. learning). This learning-performance distinction is strikingly evident when challenging practice conditions may impair practice performance, but enhance long-term retention of motor skills. A review of motor learning studies with a specific focus on comparing differences in performance between that at the end of practice and at delayed retention suggests that the delayed retention or transfer performance is a better indicator of motor learning than the performance at (or end of) practice. This provides objective evidence for the learning-performance distinction. This behavioral evidence coupled with an understanding of the motor memory processes of encoding, consolidation and retrieval may provide insight into the putative mechanism that implements the learning-performance distinction. Here, we propose a simplistic empirically-based framework--motor behavior-memory framework--that integrates the temporal evolution of motor memory processes with the time course of practice and delayed retention frequently used in behavioral motor learning paradigms. In the context of the proposed framework, recent research has used noninvasive brain stimulation to decipher the role of each motor memory process, and specific cortical brain regions engaged in motor performance and learning. Such findings provide beginning insights into the relationship between the time course of practice-induced performance changes and motor memory processes. This in turn has promising implications for future research and practical applications. Copyright © 2011 Elsevier B.V. All rights reserved.

Strategic retrieval processing and the impact of knowing when a memory was first created.

PubMed

Roberts, J S; Tsivilis, D; Mayes, A R

2014-04-01

Retrieval orientation refers to a process where participants strategically alter how a memory cue is processed in response to different task demands. In the present study we explored whether retrieval orientation is influenced by knowing when an old stimulus was first encoded. Participants completed separate remember/know test blocks for old items from a recent delay (40min) and old items from a remote delay (48h). Manipulations at encoding ensured that performance levels were matched between these two blocks, thus avoiding confounds with differences in retrieval effort. Importantly, a third test block comprised old items from both delays randomly intermixed. As the nature of the old items varies unpredictably in the mixed block, it should not be possibly to adopt a specific retrieval orientation and the mixed block therefore acts as a control condition. Participants saw the words "mixed," "recent" or "remote" prior to each test block. Comparing ERPs from the recent and remote blocks permitted an investigation of whether participants alter their retrieval orientation in response to the specific length of the retention interval. Comparing ERPs from the pure (recent and remote) test blocks to ERPs from the mixed block permitted an investigation of whether delay information per se led to differences in retrieval strategy. Analysis of the ERP data found no differences between the recent and remote blocks. However, ERPs from these pure blocks were significantly less positive than ERPs from the mixed block from 200ms towards the end of the epoch. The findings suggest that the delay information was useful in a general sense and encouraged retrieval strategies distinct from those engaged in the mixed block. We speculate that such strategies might relate to whether or not the retrieval search is specific and constrained and/or whether processes that serve to reinstate the original encoding context are engaged. Copyright © 2014 Elsevier Inc. All rights reserved.

On the Effects of Signaling Reinforcer Probability and Magnitude in Delayed Matching to Sample

ERIC Educational Resources Information Center

Brown, Glenn S.; White, K. Geoffrey

2005-01-01

Two experiments examined whether postsample signals of reinforcer probability or magnitude affected the accuracy of delayed matching to sample in pigeons. On each trial, red or green choice responses that matched red or green stimuli seen shortly before a variable retention interval were reinforced with wheat access. In Experiment 1, the…

Effects of Vocabulary Instruction Using Constant Time Delay on Expository Reading of Young Adults with Intellectual Disability

ERIC Educational Resources Information Center

Hua, Youjia; Woods-Groves, Suzanne; Kaldenberg, Erica R.; Scheidecker, Bethany J.

2013-01-01

We investigated the effectiveness of using constant time delay (CTD) with young adults with intellectual disability on their vocabulary acquisition and retention, as well as expository reading comprehension. Four learners, ages 19 to 21 years, from a postsecondary education program for individuals with disabilities participated in the study.…

Effects of Delay Duration on the WMS Logical Memory Performance of Older Adults with Probable Alzheimer's Disease, Probable Vascular Dementia, and Normal Cognition.

PubMed

Montgomery, Valencia; Harris, Katie; Stabler, Anthony; Lu, Lisa H

2017-05-01

To examine how the duration of time delay between Wechsler Memory Scale (WMS) Logical Memory I and Logical Memory II (LM) affected participants' recall performance. There are 46,146 total Logical Memory administrations to participants diagnosed with either Alzheimer's disease (AD), vascular dementia (VaD), or normal cognition in the National Alzheimer's Disease Coordinating Center's Uniform Data Set. Only 50% of the sample was administered the standard 20-35 min of delay as specified by WMS-R and WMS-III. We found a significant effect of delay time duration on proportion of information retained for the VaD group compared to its control group, which remained after adding LMI raw score as a covariate. There was poorer retention of information with longer delay for this group. This association was not as strong for the AD and cognitively normal groups. A 24.5-min delay was most optimal for differentiating AD from VaD participants (47.7% classification accuracy), an 18.5-min delay was most optimal for differentiating AD versus normal participants (51.7% classification accuracy), and a 22.5-min delay was most optimal for differentiating VaD versus normal participants (52.9% classification accuracy). Considering diagnostic implications, our findings suggest that test administration should incorporate precise tracking of delay periods. We recommend a 20-min delay with 18-25-min range. Poor classification accuracy based on LM data alone is a reminder that story memory performance is only one piece of data that contributes to complex clinical decisions. However, strict adherence to the recommended range yields optimal data for diagnostic decisions. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The effect of EarthPulse on learning of declarative knowledge

NASA Astrophysics Data System (ADS)

McKinney, Heather E.

The purpose of this double-blind, bio-medical research study was to investigate the effect of EarthPulse, a brainwave entrainment and pulsed electromagnetic field (PEMF) device, on learning of declarative knowledge. Currently, PEMF research explores physiological and psychological effects but a gap exists in the potential effects of PEMF on learning. The study explored whether a relationship existed between receiving a thirty minute EarthPulse treatment on the "Entrain Up" setting and learning of declarative knowledge; whether the relationship remained over time; whether EarthPulse had an effect on sleep; and whether EarthPulse had an effect on attrition. Ninety-eight, randomly assigned, undergraduate students participated in this double-blind, experimental design study, of which 87 remained after attrition. After receiving a thirty minute EarthPulse or placebo treatment, experimental and control groups read identical passages and completed identical instruments to test learning and retention of declarative knowledge. Participants completed the same test in two intervals: an immediate (learning) and delayed (retention) posttest. Assumptions for normality and reliability were met. One-way ANOVA revealed no statistically significant effects on learning or retention at the 0.05 level. However, Chi square analysis revealed those who received the EarthPulse treatment were significantly less likely to fall asleep than those who received the control treatment (p=0.022) and very closely approached significance for attrition (p=0.051).

A gluten-free vegan meal for gastric emptying scintigraphy: establishment of reference values and its utilization in the evaluation of diabetic gastroparesis.

PubMed

Somasundaram, Vijay Harish; Subramanyam, Padma; Palaniswamy, Shanmuga Sundaram

2014-11-01

The aim of this study was to describe the preparation of radiolabeled idli (savory cake) meal for use as an alternate to the egg white sandwich (EWS) meal in gastric emptying scintigraphy (GES). Furthermore, the aim of this study was to establish normal emptying rates for this meal and present our experience in using it in the evaluation of diabetic gastroparesis. The meal was prepared using a universally available packaged mix labeled with 1 mCi 99mTc sulfur colloid, and the stability of labeling was tested up to 4 hours in simulated gastric fluid. One hundred thirteen healthy volunteers (aged 20-78 years; 54 women, 59 men) underwent GES study using the idli meal. Gastric retention at one-half, 1, 2, and 4 hours after ingestion of the meal was estimated, and the normal limits were set using the fifth and 95th percentile values at each period. Having established its normal emptying rates, the idli meal was further used to evaluate 70 patients suspected with diabetic gastroparesis. The idli meal, with a calorific value ≈282 kcal, has a relatively higher fat content (8% of total mass) than EWS. More than 96% of 99mTc sulfur colloid remained bound to the meal after 4 hours suspension in simulated gastric fluid. Gastric retention greater than 30% and greater than 6% at 2 hours and 4 hours, respectively, indicated delayed gastric emptying, whereas retention less than 30% at 1 hour suggested rapid emptying. Among patients suspected with diabetic gastroparesis, delayed gastric emptying was identified in 76%, and rapid emptying was seen in 4.2%. Radiolabeled idli meal is a good alternative to EWS meal for routine GES, especially among patients with specific dietary restrictions.

Timing of urinary catheter removal after uncomplicated total abdominal hysterectomy: a prospective randomized trial.

PubMed

Ahmed, Magdy R; Sayed Ahmed, Waleed A; Atwa, Khaled A; Metwally, Lobna

2014-05-01

To assess whether immediate (0h), intermediate (after 6h) or delayed (after 24h) removal of an indwelling urinary catheter after uncomplicated abdominal hysterectomy can affect the rate of re-catheterization due to urinary retention, rate of urinary tract infection, ambulation time and length of hospital stay. Prospective randomized controlled trial conducted at Suez Canal University Hospital, Egypt. Two hundred and twenty-one women underwent total abdominal hysterectomy for benign gynecological diseases and were randomly allocated into three groups. Women in group A (73 patients) had their urinary catheter removed immediately after surgery. Group B (81 patients) had the catheter removed 6h post-operatively while in group C (67 patients) the catheter was removed after 24h. The main outcome measures were the frequency of urinary retention, urinary tract infections, ambulation time and length of hospital stay. There was a significantly higher number of urinary retention episodes requiring re-catheterization in the immediate removal group compared to the intermediate and delayed removal groups (16.4% versus 2.5% and 0% respectively). Delayed urinary catheter removal was associated with a higher incidence of urinary tract infections (15%), delayed ambulation time (10.3h) and longer hospital stay (5.6 days) compared to the early (1.4%, 4.1h and 3.2 days respectively) and intermediate (3.7%, 6.8h and 3.4 days respectively) removal groups. Removal of the urinary catheter 6h postoperatively appears to be more advantageous than early or late removal in cases of uncomplicated total abdominal hysterectomy. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Focused attention improves working memory: implications for flexible-resource and discrete-capacity models.

PubMed

Souza, Alessandra S; Rerko, Laura; Lin, Hsuan-Yu; Oberauer, Klaus

2014-10-01

Performance in working memory (WM) tasks depends on the capacity for storing objects and on the allocation of attention to these objects. Here, we explored how capacity models need to be augmented to account for the benefit of focusing attention on the target of recall. Participants encoded six colored disks (Experiment 1) or a set of one to eight colored disks (Experiment 2) and were cued to recall the color of a target on a color wheel. In the no-delay condition, the recall-cue was presented after a 1,000-ms retention interval, and participants could report the retrieved color immediately. In the delay condition, the recall-cue was presented at the same time as in the no-delay condition, but the opportunity to report the color was delayed. During this delay, participants could focus attention exclusively on the target. Responses deviated less from the target's color in the delay than in the no-delay condition. Mixture modeling assigned this benefit to a reduction in guessing (Experiments 1 and 2) and transposition errors (Experiment 2). We tested several computational models implementing flexible or discrete capacity allocation, aiming to explain both the effect of set size, reflecting the limited capacity of WM, and the effect of delay, reflecting the role of attention to WM representations. Both models fit the data better when a spatially graded source of transposition error is added to its assumptions. The benefits of focusing attention could be explained by allocating to this object a higher proportion of the capacity to represent color.

Neural Evidence for a Distinction between Short-Term Memory and the Focus of Attention

ERIC Educational Resources Information Center

Lewis-Peacock, Jarrod A.; Drysdale, Andrew T.; Oberauer, Klaus; Postle, Bradley R.

2012-01-01

It is widely assumed that the short-term retention of information is accomplished via maintenance of an active neural trace. However, we demonstrate that memory can be preserved across a brief delay despite the apparent loss of sustained representations. Delay period activity may, in fact, reflect the focus of attention, rather than STM. We…

The Effect of Online Gaming, Cognition and Feedback Type in Facilitating Delayed Achievement of Different Learning Objectives

ERIC Educational Resources Information Center

Cameron, Brian; Dwyer, Francis

2005-01-01

Online and computer-based instructional gaming is becoming a viable instructional strategy at all levels of education. The purpose of this study was to examine the effect of (a) gaming, (b) gaming plus embedded questions, and (c) gaming plus questions plus feedback on delayed retention of different types of educational objectives for students…

Cognitive intervention through a training program for picture book reading in community-dwelling older adults: a randomized controlled trial.

PubMed

Suzuki, Hiroyuki; Kuraoka, Masataka; Yasunaga, Masashi; Nonaka, Kumiko; Sakurai, Ryota; Takeuchi, Rumi; Murayama, Yoh; Ohba, Hiromi; Fujiwara, Yoshinori

2014-11-21

Non-pharmacological interventions are expected to be important strategies for reducing the age-adjusted prevalence of senile dementia, considering that complete medical treatment for cognitive decline has not yet been developed. From the viewpoint of long-term continuity of activity, it is necessary to develop various cognitive stimulating programs. The aim of this study is to examine the effectiveness of a cognitive intervention through a training program for picture book reading for community-dwelling older adults. Fifty-eight Japanese older participants were divided into the intervention and control groups using simple randomization (n =29 vs 29). In the intervention group, participants took part in a program aimed at learning and mastering methods of picture book reading as a form of cognitive training intervention. The control group listened to lectures about elderly health maintenance. Cognitive tests were conducted individually before and after the programs. The rate of memory retention, computed by dividing Logical Memory delayed recall by immediate recall, showed a significant interaction (p < .05) in analysis of covariance. Simple main effects showed that the rate of memory retention of the intervention group improved after the program completion (p < .05). In the participants with mild cognitive impairment (MCI) examined by Japanese version of the Montreal Cognitive Assessment (MoCA-J) (n =14 vs 15), significant interactions were seen in Trail Making Test-A (p < .01), Trail Making Test-B (p < .05), Kana pick-out test (p < .05) and the Mini-Mental State Examination (p < .05). The intervention effect was found in delayed verbal memory. This program is also effective for improving attention and executive function in those with MCI. The short-term interventional findings suggest that this program might contribute to preventing a decline in memory and executive function. UMIN000014712 (Date of ICMJE and WHO compliant trial information disclosure: 30 July 2014).

Enhanced 99Tc retention in glass waste form using Tc(IV)-incorporated Fe minerals

DOE PAGES

Um, Wooyong; Luksic, Steven A.; Wang, Guohui; ...

2017-09-07

We present that technetium ( 99Tc) immobilization by doping into iron oxide mineral phases may alleviate the problems with Tc volatility during vitrification of nuclear waste. Because reduced Tc, Tc(IV), substitutes for Fe(III) in the crystal structure by a process of Tc reduction from Tc(VII) to Tc(IV) followed by co-precipitation of Fe oxide minerals, two Tc-incorporated Fe minerals (Tc-goethite and Tc-magnetite/maghemite) were prepared and tested for Tc retention in glass melt samples at temperatures between 600 and 1000 °C. After being cooled, the solid glass specimens prepared at different temperatures at 600, 800, and 1000 °C were analyzed for Tcmore » oxidation state using Tc K-edge XANES. In most samples, Tc was partially (<60%) oxidized from Tc(IV) to Tc(VII) as the melt temperature increased up to 600 °C. However, most of Tc(IV) was completely (>95%) oxidized to Tc(VII) at temperature above 800 °C. Tc retention in glass melt samples prepared using Tc-incorporated Fe minerals were slightly higher (~10%) than in glass prepared using KTcO4 because of limited and delayed Tc volatilization.« less

Enhanced 99Tc retention in glass waste form using Tc(IV)-incorporated Fe minerals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Um, Wooyong; Luksic, Steven A.; Wang, Guohui

We present that technetium ( 99Tc) immobilization by doping into iron oxide mineral phases may alleviate the problems with Tc volatility during vitrification of nuclear waste. Because reduced Tc, Tc(IV), substitutes for Fe(III) in the crystal structure by a process of Tc reduction from Tc(VII) to Tc(IV) followed by co-precipitation of Fe oxide minerals, two Tc-incorporated Fe minerals (Tc-goethite and Tc-magnetite/maghemite) were prepared and tested for Tc retention in glass melt samples at temperatures between 600 and 1000 °C. After being cooled, the solid glass specimens prepared at different temperatures at 600, 800, and 1000 °C were analyzed for Tcmore » oxidation state using Tc K-edge XANES. In most samples, Tc was partially (<60%) oxidized from Tc(IV) to Tc(VII) as the melt temperature increased up to 600 °C. However, most of Tc(IV) was completely (>95%) oxidized to Tc(VII) at temperature above 800 °C. Tc retention in glass melt samples prepared using Tc-incorporated Fe minerals were slightly higher (~10%) than in glass prepared using KTcO4 because of limited and delayed Tc volatilization.« less

Hypoxia delays hematopoiesis: retention of embryonic hemoglobin and erythrocytes in larval rainbow trout, Oncorhynchus mykiss, during chronic hypoxia exposure.

PubMed

Bianchini, Kristin; Wright, Patricia A

2013-12-01

In rainbow trout development, a switch occurs from high-affinity embryonic hemoglobin (Hb) and round, embryonic erythrocytes to lower-affinity adult Hb and oval, adult erythrocytes. Our study investigated the early ontogeny of rainbow trout blood properties and the hypoxia response. We hypothesized that hypoxia exposure would delay the ontogenetic turnover of Hb and erythrocytes because retention of high-affinity embryonic Hb would facilitate oxygen loading. To test this hypothesis we developed a method of efficiently extracting blood from individual embryos and larvae and optimized several techniques for measuring hematological parameters on microliter (0.5-2.0 μl) blood samples. In chronic hypoxia (30% of oxygen saturation), stage-matched embryos and larvae possessed half the Hb concentration, erythrocyte counts and hematocrit observed in normoxia. Hypoxia-reared larvae also had threefold to sixfold higher mRNA expression of the embryonic Hb α-1, β-1 and β-2 subunits relative to stage-matched normoxia-reared larvae. Furthermore, in hypoxia, the round embryonic erythrocytic shape persisted into later developmental stages. Despite these differences, Hb-oxygen affinity (P50), cooperativity and the Root effect were unaltered in hypoxia-reared O. mykiss. The data support our hypothesis that chronic hypoxia delays the ontogenetic turnover of Hb and erythrocytes, but without the predicted functional consequences (i.e. higher than expected P50). These results also suggest that the Hb-oxygen affinity is protected during development in chronic hypoxia to favor oxygen unloading at the tissues. We conclude that in early trout development, the blood-oxygen transport system responds very differently to chronic hypoxia relative to adults, possibly because respiration depends relatively more on oxygen diffusion than convection.

'Hip-hop' stroke: a stroke educational program for elementary school children living in a high-risk community.

PubMed

Williams, Olajide; Noble, James M

2008-10-01

Public stroke recognition is poor and poses a barrier to acute stroke treatment. We describe a stroke literacy program that teaches elementary school children in high-risk communities to recognize stroke and form an urgent action plan; we then present results of an intervention study using the program. "Hip-Hop" Stroke uses culturally and age-appropriate music and dance to enhance an interactive didactic curriculum including the FAST mnemonic (Facial droop, Arm weakness, Speech disturbance, Time to call 911). The program occurred in central Harlem, New York City, a community with high stroke risk. During the 2006 to 2007 school year, 582 fourth, fifth, and sixth graders (9 to 11 years of age) participated in 1-hour sessions over 3 consecutive days. Stroke knowledge was tested before and after the program with a 94% group participant retention. Students learned and retained knowledge well for stroke localization (20% correct before intervention, 93% correct immediately afterward, and 86% correct after 3-month delay; P<0.001 both posttests versus baseline), the term "brain attack" (16% pretest, 95% immediate, 86% delayed; P<0.001), and to call 911 for stroke (78% pretest, 99.8% immediate, 98% delayed; P<0.001). FAST stroke symptoms (facial droop and slurred speech) were better retained than non-FAST symptoms (headache and blurred vision) at 3 months (P<0.001). For stroke prevention measures, dietary change and exercise were better learned than concepts of diabetes, hypertension, and cholesterol. Elementary school children are educable about stroke, retain their knowledge well, and may be able to appropriately activate emergency services for acute stroke. Incorporating cultural elements such as hip-hop music may improve retention of stroke knowledge among the youth.

Repetition and lag effects in movement recognition.

PubMed

Hall, C R; Buckolz, E

1982-03-01

Whether repetition and lag improve the recognition of movement patterns was investigated. Recognition memory was tested for one repetition, two-repetitions massed, and two-repetitions distributed with movement patterns at lags of 3, 5, 7, and 13. Recognition performance was examined both immediately afterwards and following a 48 hour delay. Both repetition and lag effects failed to be demonstrated, providing some support for the claim that memory is unaffected by repetition at a constant level of processing (Craik & Lockhart, 1972). There was, as expected, a significant decrease in recognition memory following the retention interval, but this appeared unrelated to repetition or lag.

Differential Effects of Paced and Unpaced Responding on delayed Serial Order Recall in Schizophrenia

PubMed Central

Hill, S. Kristian; Griffin, Ginny B.; Houk, James C.; Sweeney, John A.

2011-01-01

Working memory for temporal order is a component of working memory that is especially dependent on striatal systems, but has not been extensively studied in schizophrenia. This study was designed to characterize serial order reproduction by adapting a spatial serial order task developed for nonhuman primate studies, while controlling for working memory load and whether responses were initiated freely (unpaced) or in an externally paced format. Clinically stable schizophrenia patients (n=27) and psychiatrically healthy individuals (n=25) were comparable on demographic variables and performance on standardized tests of immediate serial order recall (Digit Span, Spatial Span). No group differences were observed for serial order recall when read sequence reproduction was unpaced. However, schizophrenia patients exhibited significant impairments when responding was paced, regardless of sequence length or retention delay. Intact performance by schizophrenia patients during the unpaced condition indicates that prefrontal storage and striatal output systems are sufficiently intact to learn novel response sequences and hold them in working memory to perform serial order tasks. However, retention for newly learned response sequences was disrupted in schizophrenia patients by paced responding, when read-out of each element in the response sequence was externally controlled. The disruption of memory for serial order in paced read-out condition indicates a deficit in frontostriatal interaction characterized by an inability to update working memory stores and deconstruct ‘chunked’ information. PMID:21705197

300 Area Building Retention Evaluation Mitigation Plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

D. J. McBride

2007-07-03

Evaluate the long-term retention of several facilities associated with the PNNL Capability Replacement Laboratory and other Hanfor mission needs. WCH prepared a mitigation plan for three scenarios with different release dates for specific buildings. The evaluations present a proposed plan for providing utility services to retained facilities in support of a long-term (+20 year) lifespan in addition to temporary services to buildings with specified delayed release dates.

Ecstasy Exposure & Gender: Examining Components of Verbal Memory Functioning

PubMed Central

Price, Jenessa S.; Shear, Paula; Lisdahl, Krista M.

2014-01-01

Objective Studies have demonstrated verbal memory deficits associated with past year ecstasy use, although specific underlying components of these deficits are less understood. Further, prior research suggests potential gender differences in ecstasy-induced serotonergic changes. Therefore, the current study investigated whether gender moderated the relationship between ecstasy exposure and components of verbal memory after controlling for polydrug use and confounding variables. Method Data were collected from 65 polydrug users with a wide range of ecstasy exposure (ages 18–35; 48 ecstasy and 17 marijuana users; 0–2310 ecstasy tablets). Participants completed a verbal learning and memory task, psychological questionnaires, and a drug use interview. Results Increased past year ecstasy exposure predicted poorer short and long delayed free and cued recalls, retention, and recall discrimination. Male ecstasy users were more susceptible to dose-dependent deficits in retention than female users. Conclusion Past year ecstasy consumption was associated with verbal memory retrieval, retention, and discrimination deficits in a dose-dependent manner in a sample of healthy young adult polydrug users. Male ecstasy users were at particular risk for deficits in retention following a long delay. Gender difference may be reflective of different patterns of polydrug use as well as increased hippocampal sensitivity. Future research examining neuronal correlates of verbal memory deficits in ecstasy users are needed. PMID:25545890

Ecstasy exposure & gender: examining components of verbal memory functioning.

PubMed

Price, Jenessa S; Shear, Paula; Lisdahl, Krista M

2014-01-01

Studies have demonstrated verbal memory deficits associated with past year ecstasy use, although specific underlying components of these deficits are less understood. Further, prior research suggests potential gender differences in ecstasy-induced serotonergic changes. Therefore, the current study investigated whether gender moderated the relationship between ecstasy exposure and components of verbal memory after controlling for polydrug use and confounding variables. Data were collected from 65 polydrug users with a wide range of ecstasy exposure (ages 18-35; 48 ecstasy and 17 marijuana users; 0-2310 ecstasy tablets). Participants completed a verbal learning and memory task, psychological questionnaires, and a drug use interview. Increased past year ecstasy exposure predicted poorer short and long delayed free and cued recalls, retention, and recall discrimination. Male ecstasy users were more susceptible to dose-dependent deficits in retention than female users. Past year ecstasy consumption was associated with verbal memory retrieval, retention, and discrimination deficits in a dose-dependent manner in a sample of healthy young adult polydrug users. Male ecstasy users were at particular risk for deficits in retention following a long delay. Gender difference may be reflective of different patterns of polydrug use as well as increased hippocampal sensitivity. Future research examining neuronal correlates of verbal memory deficits in ecstasy users are needed.

Memory Functioning in Children and Adolescents With Autism

PubMed Central

Southwick, Jason S.; Bigler, Erin D.; Froehlich, Alyson; DuBray, Molly B.; Alexander, Andrew L.; Lange, Nicholas; Lainhart, Janet E.

2012-01-01

Objective Memory functioning in children and adolescents ages 5–19 with autism (n = 50) and typically developing controls (n = 36) was assessed using a clinical assessment battery, the Test of Memory and Learning (TOMAL). Method Participant groups were statistically comparable in age, nonverbal IQ, handedness, and head circumference, and were administered the TOMAL. Results Test performance on the TOMAL demonstrated broad differences in memory functioning in the autism group, across multiple task formats, including verbal and nonverbal, immediate and delayed, attention and concentration, sequential recall, free recall, associative recall, and multiple-trial learning memory. All index and nearly all subtest differences remained significant even after comparing a subset of the autism group (n = 36) and controls that were matched for verbal IQ ( p >.05). However, retention of previously remembered information after a delay was similar in autism and controls. Conclusions These findings indicate that performance on measures of episodic memory is broadly reduced in autism, and support the conclusion that information encoding and organization, possibly due to inefficient cognitive processing strategies, rather than storage and retrieval, are the primary factors that limit memory performance in autism. PMID:21843004

Spatial Memory: Behavioral Determinants of Persistence in the Watermaze Delayed Matching-to-Place Task

ERIC Educational Resources Information Center

da Silva, Bruno M.; Bast, Tobias; Morris, Richard G. M.

2014-01-01

The watermaze delayed matching-to-place (DMP) task was modified to include probe trials, to quantify search preference for the correct place. Using a zone analysis of search preference, a gradual decay of one-trial memory in rats was observed over 24 h with weak memory consistently detected at a retention interval of 6 h, but unreliably at 24 h.…

Accurate prediction of retention in hydrophilic interaction chromatography by back calculation of high pressure liquid chromatography gradient profiles.

PubMed

Wang, Nu; Boswell, Paul G

2017-10-20

Gradient retention times are difficult to project from the underlying retention factor (k) vs. solvent composition (φ) relationships. A major reason for this difficulty is that gradients produced by HPLC pumps are imperfect - gradient delay, gradient dispersion, and solvent mis-proportioning are all difficult to account for in calculations. However, we recently showed that a gradient "back-calculation" methodology can measure these imperfections and take them into account. In RPLC, when the back-calculation methodology was used, error in projected gradient retention times is as low as could be expected based on repeatability in the k vs. φ relationships. HILIC, however, presents a new challenge: the selectivity of HILIC columns drift strongly over time. Retention is repeatable in short time, but selectivity frequently drifts over the course of weeks. In this study, we set out to understand if the issue of selectivity drift can be avoid by doing our experiments quickly, and if there any other factors that make it difficult to predict gradient retention times from isocratic k vs. φ relationships when gradient imperfections are taken into account with the back-calculation methodology. While in past reports, the accuracy of retention projections was >5%, the back-calculation methodology brought our error down to ∼1%. This result was 6-43 times more accurate than projections made using ideal gradients and 3-5 times more accurate than the same retention projections made using offset gradients (i.e., gradients that only took gradient delay into account). Still, the error remained higher in our HILIC projections than in RPLC. Based on the shape of the back-calculated gradients, we suspect the higher error is a result of prominent gradient distortion caused by strong, preferential water uptake from the mobile phase into the stationary phase during the gradient - a factor our model did not properly take into account. It appears that, at least with the stationary phase we used, column distortion is an important factor to take into account in retention projection in HILIC that is not usually important in RPLC. Copyright © 2017 Elsevier B.V. All rights reserved.

Relating gastric scintigraphy and symptoms to motility capsule transit and pressure findings in suspected gastroparesis

PubMed Central

Hasler, W. L.; May, K. P.; Wilson, L. A.; Van Natta, M.; Parkman, H. P.; Pasricha, P. J.; Koch, K. L.; Abell, T. L.; McCallum, R. W.; Nguyen, L. A.; Snape, W. J.; Sarosiek, I.; Clarke, J. O.; Farrugia, G.; Calles-Escandon, J.; Grover, M.; Tonascia, J.; Lee, L. A.; Miriel, L.; Hamilton, F. A.

2018-01-01

Background Wireless motility capsule (WMC) findings are incompletely defined in suspected gastroparesis. We aimed to characterize regional WMC transit and contractility in relation to scintigraphy, etiology, and symptoms in patients undergoing gastric emptying testing. Methods A total of 209 patients with gastroparesis symptoms at NIDDK Gastroparesis Consortium centers underwent gastric scintigraphy and WMCs on separate days to measure regional transit and contractility. Validated questionnaires quantified symptoms. Key Results Solid scintigraphy and liquid scintigraphy were delayed in 68.8% and 34.8% of patients; WMC gastric emptying times (GET) were delayed in 40.3% and showed 52.8% agreement with scintigraphy; 15.5% and 33.5% had delayed small bowel (SBTT) and colon transit (CTT) times. Transit was delayed in ≥2 regions in 23.3%. Rapid transit was rarely observed. Diabetics had slower GET but more rapid SBTT versus idiopathics (P ≤ .02). GET delays related to greater scintigraphic retention, slower SBTT, and fewer gastric contractions (P ≤ .04). Overall gastroparesis symptoms and nausea/vomiting, early satiety/fullness, bloating/distention, and upper abdominal pain subscores showed no relation to WMC transit. Upper and lower abdominal pain scores (P ≤ .03) were greater with increased colon contractions. Constipation correlated with slower CTT and higher colon contractions (P = .03). Diarrhea scores were higher with delayed SBTT and CTT (P ≤ .04). Conclusions & Inferences Wireless motility capsules define gastric emptying delays similar but not identical to scintigraphy that are more severe in diabetics and relate to reduced gastric contractility. Extragastric transit delays occur in >40% with suspected gastroparesis. Gastroparesis symptoms show little association with WMC profiles, although lower symptoms relate to small bowel or colon abnormalities. PMID:28872760

The effect of additives on release and in vitro skin retention of flavonoids from emulsion and gel semisolid formulations.

PubMed

Dyja, R; Jankowski, A

2017-08-01

To assess the effect of two different additives (propylene glycol (PG) and polyethylene glycol 400 (PEG 400)) on release and in vitro skin retention of quercetin and chrysin from semisolid bases (amphiphilic creams and acidic carbomer gels). For obtaining semisolid formulations, flavonoids were pre-dissolved in the liquid (PG or PEG 400) or directly suspended in the semisolid base. Three chrysin formulations ('cream 0', 'PG-cream' and 'PEG 400-cream') and five quercetin formulations ('cream 0', 'PG cream', 'PEG 400 cream', 'gel 0' and 'PG gel') were prepared. The release studies were carried out in Franz diffusion cells by means of a cellulose membrane. The porcine ear skin was used in in vitro skin retention studies. The dissolution was a prerequisite to increase the release rates of tested flavonoids from obtained semisolid formulations. The cumulative amount of chrysin released after 6 h from 'PEG 400 cream' containing partly dissolved form of that flavonoid was higher than that from 'cream 0' or 'PG cream' containing its suspended form. The formulations containing quercetin dissolved in PG ('PG cream', 'PG gel') or PEG 400 ('PEG 400 cream') exhibited higher release rates of that flavonoid than corresponding semisolid suspensions ('cream 0' or 'gel 0'). The effects of both liquid additives (PG and PEG 400) on the cumulative amount of quercetin released after 6 h were comparable. However, there was no correlation between the release rate and the skin retention. The amounts of the flavonoids found in the skin were strongly affected by the type of the used solvent. While PG increased the skin retention of both flavonoids, PEG 400 had no effect on chrysin skin retention and delayed quercetin skin absorption. The proper choice of the solvent added to the semisolid base is crucial for enhanced skin delivery of the tested flavonoids. PG is more efficient absorption promoter than PEG 400 of both chrysin and quercetin. © 2017 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Development of Tc(IV)-Incorporated Fe Minerals to Enhance 99Tc Retention in Glass Waste Form

DOE Office of Scientific and Technical Information (OSTI.GOV)

Um, Wooyong; Luksic, Steven A.; Wang, Guohui

Iron minerals have been considered to be good hosts for Tc immobilization because the Tc(IV) ion substitutes for Fe(III) in the crystal structure of the Fe oxide due to similarities in (1) cation size [Tc(IV) = 78.5 pm ; Fe(III) = 69 or 78.5 pm], (2) metal-oxygen interatomic distance (Tc—O = 0.199 nm, Fe—O = 0.203 nm), (3) number of coordinating oxygen atoms (both 6-fold coordinated), and (4) the redox potential (Eh=ca. +20 mV at pH = 7) for a redox couple between Tc(VII)/Tc(IV) and Fe(III)/Fe(II). Magnetite, maghemite, and trevorite are iron oxide minerals and all belong to spinel mineralmore » group. Laboratory testing shows that Tc can be removed from aqueous waste solutions by a process of Tc reduction from Tc(VII) to Tc(IV) followed by co-precipitation with iron oxide minerals during recrystallization of Fe(OH)2(s) used as an initial solid precursor. X-ray absorption near edge structure (XANES) spectroscopy confirmed that Tc was in the +4 oxidation state in final Tc-Fe minerals. The Tc-incorporated Fe minerals were also tested for Tc retention in glass melts at different temperatures between 600 – 1,000 oC in a furnace. After being cooled in air, the solid glass specimens collected at different temperatures were analyzed for Tc oxidation state using XANES and Tc retention using liquid scintillation counting (LSC). Even though Tc(IV) started to reoxidize at 600 oC, Tc retention in the final glass specimen prepared with Tc-incorporated Fe mineral even at high temperatures was at least two times higher than glass prepared with KTcO4 salt. Higher Tc retention in glass is considered to result from limited and delayed Tc volatilization process due to Fe mineral encapsulation for Tc. Therefore, the results showing the presence of Tc(IV) in the Fe mineral structure indicate strong possibility to enhance Tc retention in borosilicate glass as well as to reduce the remediation costs at the Hanford Site.« less

Cystoscopy and Ureteroscopy

MedlinePlus

... urinary urgency—the inability to delay urination urinary retention —the inability to empty the bladder completely urinary ... Coordinating Committees Strategic Plans & Reports Research Areas FAQs Jobs at NIDDK Visit Us Contact Us News News ...

Premarin improves memory, prevents scopolamine-induced amnesia and increases number of basal forebrain choline acetyltransferase positive cells in middle-aged surgically menopausal rats.

PubMed

Acosta, Jazmin I; Mayer, Loretta; Talboom, Joshua S; Zay, Cynthia; Scheldrup, Melissa; Castillo, Jonathan; Demers, Laurence M; Enders, Craig K; Bimonte-Nelson, Heather A

2009-03-01

Conjugated equine estrogen (CEE) is the most commonly prescribed estrogen therapy, and is the estrogen used in the Women's Health Initiative study. While in-vitro studies suggest that CEE is neuroprotective, no study has evaluated CEE's effects on a cognitive battery and brain immunohistochemistry in an animal model. The current experiment tested whether CEE impacted: I) spatial learning, reference memory, working memory and long-term retention, as well as ability to handle mnemonic delay and interference challenges; and, II) the cholinergic system, via pharmacological challenge during memory testing and ChAT-immunoreactive cell counts in the basal forebrain. Middle-aged ovariectomized (Ovx) rats received chronic cyclic injections of either Oil (vehicle), CEE-Low (10 microg), CEE-Medium (20 microg) or CEE-High (30 microg) treatment. Relative to the Oil group, all three CEE groups showed less overnight forgetting on the spatial reference memory task, and the CEE-High group had enhanced platform localization during the probe trial. All CEE groups exhibited enhanced learning on the spatial working memory task, and CEE dose-dependently protected against scopolamine-induced amnesia with every rat receiving the highest CEE dose maintaining zero errors after scopolamine challenge. CEE also increased number of ChAT-immunoreactive neurons in the vertical diagonal band of the basal forebrain. Neither the ability to remember after a delay nor interference, nor long-term retention, was influenced by the CEE regimen used in this study. These findings are similar to those reported previously for 17 beta-estradiol, and suggest that CEE can provide cognitive benefits on spatial learning, reference and working memory, possibly through cholinergic mechanisms.

The Influence of Microstructure on Deuterium Retention in Polycrystalline Tungsten

DOE PAGES

Garrison, Lauren M.; Meyer, Fred W.; Bannister, Mark E.

2017-09-18

The retention of hydrogen isotopes in the plasma-facing materials of a fusion reactor is dependent on the density of trapping sites in the material. One factor that can influence the trapping defects is the surface state of the material before exposure. Mechanically polished, electropolished, and recrystallized tungsten samples were compared by exposing them to 350 eV D + beams with peak fluences of ~1 × 10 24 D +/m 2 at 500 and 740 K at the Multicharged Ion Research Facility (MIRF). At the exposure temperature of 740 K, no significant retention was detected. For material exposed at 500 K,more » significant differences in retention were observed, and the order of increasing retention was recrystallized, electropolished, and mechanically polished. Lastly, the other variable besides surface treatment was the time delay between ion exposure and thermal desorption spectroscopy which also may have impacted the retention measurements if there was out-gassing of the D while samples were in storage before thermal desorption spectroscopy (TDS).« less

The Influence of Microstructure on Deuterium Retention in Polycrystalline Tungsten

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garrison, Lauren M.; Meyer, Fred W.; Bannister, Mark E.

The retention of hydrogen isotopes in the plasma-facing materials of a fusion reactor is dependent on the density of trapping sites in the material. One factor that can influence the trapping defects is the surface state of the material before exposure. Mechanically polished, electropolished, and recrystallized tungsten samples were compared by exposing them to 350 eV D + beams with peak fluences of ~1 × 10 24 D +/m 2 at 500 and 740 K at the Multicharged Ion Research Facility (MIRF). At the exposure temperature of 740 K, no significant retention was detected. For material exposed at 500 K,more » significant differences in retention were observed, and the order of increasing retention was recrystallized, electropolished, and mechanically polished. Lastly, the other variable besides surface treatment was the time delay between ion exposure and thermal desorption spectroscopy which also may have impacted the retention measurements if there was out-gassing of the D while samples were in storage before thermal desorption spectroscopy (TDS).« less

Electrophysiological Evidence for a Sensory Recruitment Model of Somatosensory Working Memory.

PubMed

Katus, Tobias; Grubert, Anna; Eimer, Martin

2015-12-01

Sensory recruitment models of working memory assume that information storage is mediated by the same cortical areas that are responsible for the perceptual processing of sensory signals. To test this assumption, we measured somatosensory event-related brain potentials (ERPs) during a tactile delayed match-to-sample task. Participants memorized a tactile sample set at one task-relevant hand to compare it with a subsequent test set on the same hand. During the retention period, a sustained negativity (tactile contralateral delay activity, tCDA) was elicited over primary somatosensory cortex contralateral to the relevant hand. The amplitude of this component increased with memory load and was sensitive to individual limitations in memory capacity, suggesting that the tCDA reflects the maintenance of tactile information in somatosensory working memory. The tCDA was preceded by a transient negativity (N2cc component) with a similar contralateral scalp distribution, which is likely to reflect selection of task-relevant tactile stimuli at the encoding stage. The temporal sequence of N2cc and tCDA components mirrors previous observations from ERP studies of working memory in vision. The finding that the sustained somatosensory delay period activity varies as a function of memory load supports a sensory recruitment model for spatial working memory in touch. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Neural evidence for a distinction between short-term memory and the focus of attention.

PubMed

Lewis-Peacock, Jarrod A; Drysdale, Andrew T; Oberauer, Klaus; Postle, Bradley R

2012-01-01

It is widely assumed that the short-term retention of information is accomplished via maintenance of an active neural trace. However, we demonstrate that memory can be preserved across a brief delay despite the apparent loss of sustained representations. Delay period activity may, in fact, reflect the focus of attention, rather than STM. We unconfounded attention and memory by causing external and internal shifts of attention away from items that were being actively retained. Multivariate pattern analysis of fMRI indicated that only items within the focus of attention elicited an active neural trace. Activity corresponding to representations of items outside the focus quickly dropped to baseline. Nevertheless, this information was remembered after a brief delay. Our data also show that refocusing attention toward a previously unattended memory item can reactivate its neural signature. The loss of sustained activity has long been thought to indicate a disruption of STM, but our results suggest that, even for small memory loads not exceeding the capacity limits of STM, the active maintenance of a stimulus representation may not be necessary for its short-term retention.

Increasing the graduation rates of minority medical students.

PubMed

Payne, J L; Nowacki, C M; Girotti, J A; Townsel, J; Plagge, J C; Beckham, T W

1986-05-01

The University of Illinois College of Medicine has operated a program since 1969 to recruit minority students into the college and to increase the graduation rates of these students once they enroll. Known as the Medical Opportunities Program (MOP) until 1978, the program was expanded in 1978 and renamed the Urban Health Program (UHP). The authors of the present paper discuss the results of these programs, particularly the effect of granting minority students delays in completing graduation requirements. The MOP (1969 through 1978) increased graduation rates for minority students from 55 percent for those who graduated on time to 81 percent for both on-time and delayed graduates. Under the first seven years of the UHP (1979 through 1985), more minority students have been offered places, and more have enrolled than in the 10 years of the MOP. The retention rate under the UHP, if it holds, will be higher than that under the MOP. For the combined MOP-UHP period, the retention rate for minority students was 88 percent; 69.8 percent of the graduates were on time, and 30.2 were delayed.

The influence of memory and attention on the ear advantage in dichotic listening.

PubMed

D'Anselmo, Anita; Marzoli, Daniele; Brancucci, Alfredo

2016-12-01

The role of memory retention and attentional control on hemispheric asymmetry was investigated using a verbal dichotic listening paradigm, with the consonant-vowel syllables (/ba/,/da/,/ga/,/ka/,/pa/and/ta/), while manipulating the focus of attention and the time interval between stimulus and response. Attention was manipulated using three conditions: non-forced (NF), forced left (FL) and forced right (FR) attention. Memory involvement was varied using four delays (0, 1, 3 and 4 s) between stimulus presentation and response. Results showed a significant right ear advantage (REA) in the NF condition and an increased REA in the FR condition. A left ear advantage (LEA) was found in FL condition. The REA increased significantly in the NF attention condition at the 3-s compared to the 0-s delay and in the FR condition at the 1-s compared to the 0-s delay. No modulation of the left ear advantage was observed in the FL condition. These results are discussed in terms of an interaction between attentional processes and memory retention. Copyright © 2016 Elsevier B.V. All rights reserved.

COURSES OF MISRECALL OVER LONG-TERM RETENTION INTERVALS AS RELATED TO STRENGTH OF PRE-EXPERIMENTAL HABITS OF WORD ASSOCIATION.

ERIC Educational Resources Information Center

BILODEAU, EDWARD A.; BLICK, KENNETH A.

THIS STUDY WAS MADE TO COMPARE THE EFFECTS OF STIMULATION AND NONSTIMULATION ON RECALL OF WORDS FOLLOWING TIME-DELAY PERIODS. THE SUBJECTS (670 AIRMEN) WERE TRAINED WITH AN EXAMPLE WORD LIST AND TWO WORD LISTS CONTAINING FIVE OF THE SECONDARY WORDS ASSOCIATED WITH RUSSELL-JENKINS STIMULUS WORDS. AFTER TIME DELAYS OF 2 MINUTES, 20 MINUTES, 2 DAYS,…

Dynamic adjustments in prefrontal, hippocampal, and inferior temporal interactions with increasing visual working memory load.

PubMed

Rissman, Jesse; Gazzaley, Adam; D'Esposito, Mark

2008-07-01

The maintenance of visual stimuli across a delay interval in working memory tasks is thought to involve reverberant neural communication between the prefrontal cortex and posterior visual association areas. Recent studies suggest that the hippocampus might also contribute to this retention process, presumably via reciprocal interactions with visual regions. To characterize the nature of these interactions, we performed functional connectivity analysis on an event-related functional magnetic resonance imaging data set in which participants performed a delayed face recognition task. As the number of faces that participants were required to remember was parametrically increased, the right inferior frontal gyrus (IFG) showed a linearly decreasing degree of functional connectivity with the fusiform face area (FFA) during the delay period. In contrast, the hippocampus linearly increased its delay period connectivity with both the FFA and the IFG as the mnemonic load increased. Moreover, the degree to which participants' FFA showed a load-dependent increase in its connectivity with the hippocampus predicted the degree to which its connectivity with the IFG decreased with load. Thus, these neural circuits may dynamically trade off to accommodate the particular mnemonic demands of the task, with IFG-FFA interactions mediating maintenance at lower loads and hippocampal interactions supporting retention at higher loads.

Formulation and optimization of zinc-pectinate beads for the controlled delivery of resveratrol.

PubMed

Das, Surajit; Ng, Ka-Yun; Ho, Paul C

2010-06-01

Preventive and therapeutic efficacies of resveratrol on several lower gastrointestinal (GI) diseases (e.g., colorectal cancer, colitis) are well documented. To overcome the problems due to its rapid absorption and metabolism at the upper GI tract, a delayed release formulation of resveratrol was designed to treat these lower GI diseases. The current study aimed to develop a delayed release formulation of resveratrol as multiparticulate pectinate beads by varying different formulation parameters. Zinc-pectinate (Zn-pectinate) beads exhibited better delayed drug release pattern than calcium-pectinate (Ca-pectinate) beads. The effects of the formulation parameters were investigated on shape, size, Zn content, moisture content, drug encapsulation efficiency, swelling-erosion, and resveratrol retention pattern of the formulated beads. Upon optimization of the formulation parameters in relative to the drug release profiles, the optimized beads were further subjected to morphological, chemical interaction, enzymatic degradation, and stability studies. Almost all prepared beads were spherical with approximately 1 mm diameter and efficiently encapsulated resveratrol. The formulation parameters revealed great influence on resveratrol retention and swelling-erosion behavior. In most of the cases, the drug release data more appropriately fitted with zero-order equation. This study demonstrates that the optimized Zn-pectinate beads can encapsulate very high amount of resveratrol and can be used as delayed release formulation of resveratrol.

Paradoxical effects of testing: retrieval enhances both accurate recall and suggestibility in eyewitnesses.

PubMed

Chan, Jason C K; Langley, Moses M

2011-01-01

Although retrieval practice typically enhances memory retention, it can also impair subsequent eyewitness memory accuracy (Chan, Thomas, & Bulevich, 2009). Specifically, participants who had taken an initial test about a witnessed event were more likely than nontested participants to recall subsequently encountered misinformation—an effect we called retrieval-enhanced suggestibility (RES). Here, we sought to test the generality of RES and to further elucidate its underlying mechanisms. To that end, we tested a dual mechanism account, which suggests that RES occurs because initial testing (a) enhances learning of the later misinformation by reducing proactive interference and (b) causes the reactivated memory trace to be more susceptible to later interference (i.e., a reconsolidation account). Three major findings emerged. First, RES was found after a 1-week delay, where a robust testing benefit occurred for event details that were not contradicted by later misinformation. Second, blockage of reconsolidation was unnecessary for RES to occur. Third, initial testing enhanced learning of the misinformation even when proactive interference played a minimal role.

Robotic technology results in faster and more robust surgical skill acquisition than traditional laparoscopy.

PubMed

Moore, Lee J; Wilson, Mark R; Waine, Elizabeth; Masters, Rich S W; McGrath, John S; Vine, Samuel J

2015-03-01

Technical surgical skills are said to be acquired quicker on a robotic rather than laparoscopic platform. However, research examining this proposition is scarce. Thus, this study aimed to compare the performance and learning curves of novices acquiring skills using a robotic or laparoscopic system, and to examine if any learning advantages were maintained over time and transferred to more difficult and stressful tasks. Forty novice participants were randomly assigned to either a robotic- or laparoscopic-trained group. Following one baseline trial on a ball pick-and-drop task, participants performed 50 learning trials. Participants then completed an immediate retention trial and a transfer trial on a two-instrument rope-threading task. One month later, participants performed a delayed retention trial and a stressful multi-tasking trial. The results revealed that the robotic-trained group completed the ball pick-and-drop task more quickly and accurately than the laparoscopic-trained group across baseline, immediate retention, and delayed retention trials. Furthermore, the robotic-trained group displayed a shorter learning curve for accuracy. The robotic-trained group also performed the more complex rope-threading and stressful multi-tasking transfer trials better. Finally, in the multi-tasking trial, the robotic-trained group made fewer tone counting errors. The results highlight the benefits of using robotic technology for the acquisition of technical surgical skills.

Neuropathologic Associations of Learning and Memory in Primary Progressive Aphasia.

PubMed

Kielb, Stephanie; Cook, Amanda; Wieneke, Christina; Rademaker, Alfred; Bigio, Eileen H; Mesulam, Marek-Marsel; Rogalski, Emily; Weintraub, Sandra

2016-07-01

The dementia syndrome of primary progressive aphasia (PPA) can be caused by 1 of several neuropathologic entities, including forms of frontotemporal lobar degeneration (FTLD) or Alzheimer disease (AD). Although episodic memory is initially spared in this syndrome, the subtle learning and memory features of PPA and their neuropathologic associations have not been characterized. To detect subtle memory differences on the basis of autopsy-confirmed neuropathologic diagnoses in PPA. Retrospective analysis was conducted at the Northwestern Cognitive Neurology and Alzheimer's Disease Center in August 2015 using clinical and postmortem autopsy data that had been collected between August 1983 and June 2012. Thirteen patients who had the primary clinical diagnosis of PPA and an autopsy-confirmed diagnosis of either AD (PPA-AD) or a tau variant of FTLD (PPA-FTLD) and 6 patients who had the clinical diagnosis of amnestic dementia and autopsy-confirmed AD (AMN-AD) were included. Scores on the effortless learning, delayed retrieval, and retention conditions of the Three Words Three Shapes test, a specialized measure of verbal and nonverbal episodic memory. The PPA-FTLD (n = 6), PPA-AD (n = 7), and AMN-AD (n = 6) groups did not differ by demographic composition (all P > .05). The sample mean (SD) age was 64.1 (10.3) years at symptom onset and 67.9 (9.9) years at Three Words Three Shapes test administration. The PPA-FTLD group had normal (ie, near-ceiling) scores on all verbal and nonverbal test conditions. Both the PPA-AD and AMN-AD groups had deficits in verbal effortless learning (mean [SD] number of errors, 9.9 [4.6] and 14.2 [2.0], respectively) and verbal delayed retrieval (mean [SD] number of errors, 6.1 [5.9] and 12.0 [4.4], respectively). The AMN-AD group had additional deficits in nonverbal effortless learning (mean [SD] number of errors, 10.3 [4.0]) and verbal retention (mean [SD] number of errors, 8.33 [5.2]), which were not observed in the PPA-FTLD or PPA-AD groups (all P < .005). This study identified neuropathologic associations of learning and memory in autopsy-confirmed cases of PPA. Among patients with clinical PPA syndrome, AD neuropathology appeared to interfere with effortless learning and delayed retrieval of verbal information, whereas FTLD-tau pathology did not. The results provide directions for future research on the interactions between limbic and language networks.

Immediate memory for “when, where and what”: Short‐delay retrieval using dynamic naturalistic material

PubMed Central

Macaluso, Emiliano

2015-01-01

Abstract We investigated the neural correlates supporting three kinds of memory judgments after very short delays using naturalistic material. In two functional magnetic resonance imaging (fMRI) experiments, subjects watched short movie clips, and after a short retention (1.5–2.5 s), made mnemonic judgments about specific aspects of the clips. In Experiment 1, subjects were presented with two scenes and required to either choose the scene that happened earlier in the clip (“scene‐chronology”), or with a correct spatial arrangement (“scene‐layout”), or that had been shown (“scene‐recognition”). To segregate activity specific to seen versus unseen stimuli, in Experiment 2 only one probe image was presented (either target or foil). Across the two experiments, we replicated three patterns underlying the three specific forms of memory judgment. The precuneus was activated during temporal‐order retrieval, the superior parietal cortex was activated bilaterally for spatial‐related configuration judgments, whereas the medial frontal cortex during scene recognition. Conjunction analyses with a previous study that used analogous retrieval tasks, but a much longer delay (>1 day), demonstrated that this dissociation pattern is independent of retention delay. We conclude that analogous brain regions mediate task‐specific retrieval across vastly different delays, consistent with the proposal of scale‐invariance in episodic memory retrieval. Hum Brain Mapp 36:2495–2513, 2015. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc. PMID:25773646

The role of encoding and attention in facial emotion memory: an EEG investigation.

PubMed

Brenner, Colleen A; Rumak, Samuel P; Burns, Amy M N; Kieffaber, Paul D

2014-09-01

Facial expressions are encoded via sensory mechanisms, but meaning extraction and salience of these expressions involve cognitive functions. We investigated the time course of sensory encoding and subsequent maintenance in memory via EEG. Twenty-nine healthy participants completed a facial emotion delayed match-to-sample task. P100, N170 and N250 ERPs were measured in response to the first stimulus, and evoked theta power (4-7Hz) was measured during the delay interval. Negative facial expressions produced larger N170 amplitudes and greater theta power early in the delay. N170 amplitude correlated with theta power, however larger N170 amplitude coupled with greater theta power only predicted behavioural performance for one emotion condition (very happy) out of six tested (see Supplemental Data). These findings indicate that the N170 ERP may be sensitive to emotional facial expressions when task demands require encoding and retention of this information. Furthermore, sustained theta activity may represent continued attentional processing that supports short-term memory, especially of negative facial stimuli. Further study is needed to investigate the potential influence of these measures, and their interaction, on behavioural performance. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Process Assessment

ERIC Educational Resources Information Center

Kratochwill, Thomas R.; Green, Leslie M.

1978-01-01

Results of a study of process assessment (assessing children by teaching them new material) of four children (mean age=6.6 years) with delayed reading skills are discussed in terms of the classroom use of measurement of children's retention. (CL)

16 CFR 1203.16 - Dynamic strength of retention system test.

Code of Federal Regulations, 2011 CFR

2011-01-01

... stirrup. (2) Mark the pre-test position of the retention system, with the entire dynamic test apparatus... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Dynamic strength of retention system test... retention system test. (a) Test equipment. (1) ISO headforms without the lower chin portion shall be used...

16 CFR 1203.16 - Dynamic strength of retention system test.

Code of Federal Regulations, 2010 CFR

2010-01-01

... stirrup. (2) Mark the pre-test position of the retention system, with the entire dynamic test apparatus... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Dynamic strength of retention system test... retention system test. (a) Test equipment. (1) ISO headforms without the lower chin portion shall be used...

16 CFR 1203.16 - Dynamic strength of retention system test.

Code of Federal Regulations, 2014 CFR

2014-01-01

... stirrup. (2) Mark the pre-test position of the retention system, with the entire dynamic test apparatus... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Dynamic strength of retention system test... retention system test. (a) Test equipment. (1) ISO headforms without the lower chin portion shall be used...

16 CFR 1203.16 - Dynamic strength of retention system test.

Code of Federal Regulations, 2012 CFR

2012-01-01

... stirrup. (2) Mark the pre-test position of the retention system, with the entire dynamic test apparatus... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Dynamic strength of retention system test... retention system test. (a) Test equipment. (1) ISO headforms without the lower chin portion shall be used...

16 CFR § 1203.16 - Dynamic strength of retention system test.

Code of Federal Regulations, 2013 CFR

2013-01-01

... stirrup. (2) Mark the pre-test position of the retention system, with the entire dynamic test apparatus... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Dynamic strength of retention system test. Â... retention system test. (a) Test equipment. (1) ISO headforms without the lower chin portion shall be used...

The Effectiveness of Using the 7E's Learning Cycle Strategy on the Immediate and Delayed Mathematics Achievement and the Longitudinal Impact of Learning among Preparatory Year Students at King Saud University (KSU)

ERIC Educational Resources Information Center

Khashan, Khaled

2016-01-01

This study aimed to investigate the effectiveness of teaching Mathematics by using 7E's Learning Cycle strategy in immediate and delayed achievement and retention among Preparatory Year students at King Saud University (KSU)--Saudi Arabia, in comparison with the traditional method. The study sample consisted of (73) Preparatory Year students at…

Collaborative remembering revisited: Study context access modulates collaborative inhibition and later benefits for individual memory.

PubMed

Abel, Magdalena; Bäuml, Karl-Heinz T

2017-11-01

Collaborating groups typically show reduced recall relative to nominal groups, i.e., to the cumulated non-redundant recall of the same number of people remembering in isolation-a finding termed collaborative inhibition. Motivated by the results of several previous studies, this study examined in two experiments whether access to study context at test influences the effects of collaboration. In both experiments, subjects collaborated in triads or recalled previously studied material in isolation. Experiment 1 applied short versus prolonged retention intervals to vary access to study context at test, whereas Experiment 2 used the list-method directed forgetting task and applied remember versus forget instructions to modulate context access. In both experiments, collaborative inhibition was present when access to study context at test was intact (i.e., after the short delay and the remember instruction) but was eliminated when the access was impaired (i.e., after the prolonged delay and the forget instruction). Also, post-collaborative gains for individual recall were greater when context access was impaired and collaborative inhibition was eliminated. The findings demonstrate a critical role of access to study context at test for collaborative inhibition, indicating that impaired context access may reflect a general boundary condition for the recall impairment. The possible role of context reactivation processes for beneficial effects of social recall is discussed.

An interpolated activity during the knowledge-of-results delay interval eliminates the learning advantages of self-controlled feedback schedules.

PubMed

Carter, Michael J; Ste-Marie, Diane M

2017-03-01

The learning advantages of self-controlled knowledge-of-results (KR) schedules compared to yoked schedules have been linked to the optimization of the informational value of the KR received for the enhancement of one's error-detection capabilities. This suggests that information-processing activities that occur after motor execution, but prior to receiving KR (i.e., the KR-delay interval) may underlie self-controlled KR learning advantages. The present experiment investigated whether self-controlled KR learning benefits would be eliminated if an interpolated activity was performed during the KR-delay interval. Participants practiced a waveform matching task that required two rapid elbow extension-flexion reversals in one of four groups using a factorial combination of choice (self-controlled, yoked) and KR-delay interval (empty, interpolated). The waveform had specific spatial and temporal constraints, and an overall movement time goal. The results indicated that the self-controlled + empty group had superior retention and transfer scores compared to all other groups. Moreover, the self-controlled + interpolated and yoked + interpolated groups did not differ significantly in retention and transfer; thus, the interpolated activity eliminated the typically found learning benefits of self-controlled KR. No significant differences were found between the two yoked groups. We suggest the interpolated activity interfered with information-processing activities specific to self-controlled KR conditions that occur during the KR-delay interval and that these activities are vital for reaping the associated learning benefits. These findings add to the growing evidence that challenge the motivational account of self-controlled KR learning advantages and instead highlights informational factors associated with the KR-delay interval as an important variable for motor learning under self-controlled KR schedules.

Self-regulated learning in simulation-based training: a systematic review and meta-analysis.

PubMed

Brydges, Ryan; Manzone, Julian; Shanks, David; Hatala, Rose; Hamstra, Stanley J; Zendejas, Benjamin; Cook, David A

2015-04-01

Self-regulated learning (SRL) requires an active learner who has developed a set of processes for managing the achievement of learning goals. Simulation-based training is one context in which trainees can safely practise learning how to learn. The purpose of the present study was to evaluate, in the simulation-based training context, the effectiveness of interventions designed to support trainees in SRL activities. We used the social-cognitive model of SRL to guide a systematic review and meta-analysis exploring the links between instructor supervision, supports or scaffolds for SRL, and educational outcomes. We searched databases including MEDLINE and Scopus, and previous reviews, for material published until December 2011. Studies comparing simulation-based SRL interventions with another intervention for teaching health professionals were included. Reviewers worked independently and in duplicate to extract information on learners, study quality and educational outcomes. We used random-effects meta-analysis to compare the effects of supervision (instructor present or absent) and SRL educational supports (e.g. goal-setting study guides present or absent). From 11,064 articles, we included 32 studies enrolling 2482 trainees. Only eight of the 32 studies included educational supports for SRL. Compared with instructor-supervised interventions, unsupervised interventions were associated with poorer immediate post-test outcomes (pooled effect size: -0.34, p = 0.09; n = 19 studies) and negligible effects on delayed (i.e. > 1 week) retention tests (pooled effect size: 0.11, p = 0.63; n = 8 studies). Interventions including SRL supports were associated with small benefits compared with interventions without supports on both immediate post-tests (pooled effect size: 0.23, p = 0.22; n = 5 studies) and delayed retention tests (pooled effect size: 0.44, p = 0.067; n = 3 studies). Few studies in the simulation literature have designed SRL training to explicitly support trainees' capacity to self-regulate their learning. We recommend that educators and researchers shift from thinking about SRL as learning alone to thinking of SRL as comprising a shared responsibility between the trainee and the instructional designer (i.e. learning using designed supports that help prepare individuals for future learning). © 2015 John Wiley & Sons Ltd.

Delayed dehiscence of the pericarp: role in germination and retention of viability of seeds of two cold desert annual Brassicaceae species.

PubMed

Lu, J J; Tan, D Y; Baskin, C C; Baskin, J M

2017-01-01

Considerable variation occurs in post-maturity timing of dehiscence in fruits of Brassicaceae species, and several studies have shown that the pericarp plays an important role in seed germination and retention of viability in species with indehiscent fruits. However, little is known about the significance to seed biology of delay in pericarp dehiscence for <1 year in the field. Thus, we determined the role of the pericarps of Leptaleum filifolium and Neotorularia korolkovii, which open in <1 year after fruit maturity and dispersal, in seed germination and retention of seed viability. We compared dormancy-break via after-ripening in the laboratory and germination phenology and retention of seed viability in intact siliques and isolated seeds buried in an experimental garden. Seeds of both species have Type 6 non-deep physiological dormancy, which is enhanced by the pericarp. Seeds of both species after-ripened during summer 2013, and some of them germinated in autumn and some in the following spring in watered and non-watered soil. Germination percentages of seeds in siliques increased in soil in spring 2014, after the pericarps had opened. Most isolated seeds of L. filifolium and N. korolkovii had germinated or were dead by spring 2014 and summer 2015, respectively, whereas 60% of the seeds of both species in the (opened) pericarps were viable after 24 months. Thus, although the pericarp opened 9-10 months after burial, its presence had a significant effect on seed dormancy, germination phenology and retention of viability of seeds of L. filifolium and N. korolkovii. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Transport and retention of surfactant- and polymer-stabilized engineered silver nanoparticles in silicate-dominated aquifer material.

PubMed

Adrian, Yorck F; Schneidewind, Uwe; Bradford, Scott A; Simunek, Jirka; Fernandez-Steeger, Tomas M; Azzam, Rafig

2018-05-01

Packed column experiments were conducted to investigate the transport and blocking behavior of surfactant- and polymer-stabilized engineered silver nanoparticles (Ag-ENPs) in saturated natural aquifer media with varying content of material < 0.063 mm in diameter (silt and clay fraction), background solution chemistry, and flow velocity. Breakthrough curves for Ag-ENPs exhibited blocking behavior that frequently produced a delay in arrival time in comparison to a conservative tracer that was dependent on the physicochemical conditions, and then a rapid increase in the effluent concentration of Ag-ENPs. This breakthrough behavior was accurately described using one or two irreversible retention sites that accounted for Langmuirian blocking on one site. Simulated values for the total retention rate coefficient and the maximum solid phase concentration of Ag-ENPs increased with increasing solution ionic strength, cation valence, clay and silt content, decreasing flow velocity, and for polymer-instead of surfactant-stabilized Ag-ENPs. Increased Ag-ENP retention with ionic strength occurred because of compression of the double layer and lower magnitudes in the zeta potential, whereas lower velocities increased the residence time and decreased the hydrodynamics forces. Enhanced Ag-ENP interactions with cation valence and clay were attributed to the creation of cation bridging in the presence of Ca 2+ . The delay in breakthrough was always more pronounced for polymer-than surfactant-stabilized Ag-ENPs, because of differences in the properties of the stabilizing agents and the magnitude of their zeta-potential was lower. Our results clearly indicate that the long-term transport behavior of Ag-ENPs in natural, silicate dominated aquifer material will be strongly dependent on blocking behavior that changes with the physicochemical conditions and enhanced Ag-ENP transport may occur when retention sites are filled. Copyright © 2018 Elsevier Ltd. All rights reserved.

Stroboscopic visual training improves information encoding in short-term memory.

PubMed

Appelbaum, L Gregory; Cain, Matthew S; Schroeder, Julia E; Darling, Elise F; Mitroff, Stephen R

2012-11-01

The visual system has developed to transform an undifferentiated and continuous flow of information into discrete and manageable representations, and this ability rests primarily on the uninterrupted nature of the input. Here we explore the impact of altering how visual information is accumulated over time by assessing how intermittent vision influences memory retention. Previous work has shown that intermittent, or stroboscopic, visual training (i.e., practicing while only experiencing snapshots of vision) can enhance visual-motor control and visual cognition, yet many questions remain unanswered about the mechanisms that are altered. In the present study, we used a partial-report memory paradigm to assess the possible changes in visual memory following training under stroboscopic conditions. In Experiment 1, the memory task was completed before and immediately after a training phase, wherein participants engaged in physical activities (e.g., playing catch) while wearing either specialized stroboscopic eyewear or transparent control eyewear. In Experiment 2, an additional group of participants underwent the same stroboscopic protocol but were delayed 24 h between training and assessment, so as to measure retention. In comparison to the control group, both stroboscopic groups (immediate and delayed retest) revealed enhanced retention of information in short-term memory, leading to better recall at longer stimulus-to-cue delays (640-2,560 ms). These results demonstrate that training under stroboscopic conditions has the capacity to enhance some aspects of visual memory, that these faculties generalize beyond the specific tasks that were trained, and that trained improvements can be maintained for at least a day.

Time gradient for post-test vulnerability to scopolamine-induced amnesia following the initial acquisition session of a spatial reference memory task in mice.

PubMed

Toumane, A; Durkin, T P

1993-09-01

The time course for vulnerability to the amnestic effects of the cholinergic antagonist, scopolamine, during the postacquisition period has been investigated. We have examined the effects of post-test injections of scopolamine (1 mg/kg ip) given at different times from 30 s for up to 6 h following the end of the first acquisition session of a concurrent spatial discrimination (reference memory) protocol in an 8-arm radial maze on subsequent long-term (24 h) retention performance in C57BL/6 mice. Results show that the immediate (30 s) post-test injection of scopolamine-HCl on Day 1 produces marked perturbation (amnesia) of long-term retention as attested to by significant deficits in various indices of spatial discrimination performance gain on Day 2 as compared to control subjects injected either with scopolamine-MBr or saline. The severity of this scopolamine-induced amnesia declines only slightly as a function of the treatment period 30 s-3 h post-test. However, no evidence for amnesia is observed if scopolamine-HCl injections are delayed for 6 h postsession. This important latter observation attests to the absence of any significant proactive effects of scopolamine on the ability of mice to perform the retention test via possible long-term effects on attention, motivation, or locomotor performance. These results thus constitute evidence for the existence of a limited (30 s-3 h) time gradient for vulnerability of the early memory trace to disruption by scopolamine. The present results are discussed in relation to our previous direct neurochemical observations describing the differential time courses of intervention of the ascending septohippocampal and nBM-cortical cholinergic pathways in the postlearning period. In particular, the presently observed time window concerning post-test vulnerability to scopolamine-induced amnesia corresponds more closely to the time course of the acute activation of the nBM-cortical cholinergic pathway, induced by testing with the same spatial memory protocol as used in the present study in mice.

Neural Evidence for a Distinction Between Short-Term Memory and the Focus of Attention

PubMed Central

Lewis-Peacock, Jarrod A.; Drysdale, Andrew T.; Oberauer, Klaus; Postle, Bradley R.

2011-01-01

It is widely assumed that the short-term retention of information is accomplished via maintenance of an active neural trace. However, we demonstrate that memory can be preserved across a brief delay despite the apparent loss of sustained representations. Delay-period activity may in fact reflect the focus of attention, rather than short-term memory. We unconfounded attention and memory by causing external and internal shifts of attention away from items that were being actively retained. Multivariate pattern analysis of fMRI indicated that only items within the focus of attention elicited an active neural trace. Activity corresponding to representations of items outside the focus quickly dropped to baseline. Nevertheless, this information was remembered after a brief delay. Our data also show that refocusing attention towards a previously unattended memory item can reactivate its neural signature. The loss of sustained activity has long been thought to indicate a disruption of short-term memory, but our results suggest that, even for small memory loads not exceeding the capacity limits of short-term memory, the active maintenance of a stimulus representation may not be necessary for its short-term retention. PMID:21955164

Changes to nurses' practice environment over time.

PubMed

Roche, Michael A; Duffield, Christine; Friedman, Sarah; Twigg, Di; Dimitrelis, Sofia; Rowbotham, Samantha

2016-07-01

To examine changes in the nursing practice environment, retention-related factors, unit stability and patient care tasks delayed or left undone, over two periods between 2004 and 2013. Positive nurse practice environments have been linked to nurse retention and care quality outcomes. The collection of the Practice Environment Scale of the Nursing Work Index, job satisfaction, intent to leave, unit instability and tasks delayed or not done at six acute-care hospitals across three Australian states, in two waves between 2004 and 2013; results from the two waves are compared. On average, practice environment scores declined slightly; nurses reported a greater difficulty in finding another nursing position, lower intent to leave their current job and greater instability in their current position. Rates of delayed tasks increased over the period, whereas rates of tasks left undone have decreased over the period. The decline in nurses' perceptions of the quality of the practice environment is disappointing, particularly given the protracted workforce shortages that have persisted. Significant organisational restructuring and turnover of nurse executives may have contributed to this decline. Managers need to apply existing evidence to improve nurse practice environments and manage instability. © 2016 John Wiley & Sons Ltd.

The spacing effect in immediate and delayed free recall.

PubMed

Godbole, Namrata R; Delaney, Peter F; Verkoeijen, Peter P J L

2014-01-01

Spacing repetitions improves learning relative to massing repetitions (the spacing effect). While most studies have examined the spacing effect at short retention intervals, there are contradictory claims about its fate at a delay. Certain empirical findings suggest that the spacing effect persists at a delay. However, a recent theoretical account proposes that in free recall the spacing effect should disappear at a delay. The few studies that have examined the spacing effect at a delay are sub-optimally designed, preventing an unbiased conclusion. The current study used incidental learning and controlled recency and encoding strategy in order to examine the effect of delay on the recall of spaced items within a free recall paradigm. The results demonstrated that the spacing effect persists after a delay. The results point to an important dissociation between intentional forgetting and context-change designs (which produce more forgetting of spaced than massed items) and the passage of time (which produces similar forgetting of spaced and massed items).

Mnemonic neuronal activity in somatosensory cortex.

PubMed Central

Zhou, Y D; Fuster, J M

1996-01-01

Single-unit activity was recorded from the hand areas of the somatosensory cortex of monkeys trained to perform a haptic delayed matching to sample task with objects of identical dimensions but different surface features. During the memory retention period of the task (delay), many units showed sustained firing frequency change, either excitation or inhibition. In some cases, firing during that period was significantly higher after one sample object than after another. These observations indicate the participation of somatosensory neurons not only in the perception but in the short-term memory of tactile stimuli. Neurons most directly implicated in tactile memory are (i) those with object-selective delay activity, (ii) those with nondifferential delay activity but without activity related to preparation for movement, and (iii) those with delay activity in the haptic-haptic delayed matching task but no such activity in a control visuo-haptic delayed matching task. The results indicate that cells in early stages of cortical somatosensory processing participate in haptic short-term memory. PMID:8927629

The Effect of Testing on the Retention of Coherent and Incoherent Text Material

ERIC Educational Resources Information Center

de Jonge, Mario; Tabbers, Huib K.; Rikers, Remy M. J. P.

2015-01-01

Research has shown that testing during learning can enhance the long-term retention of text material. In two experiments, we investigated the testing effect with a fill-in-the-blank test on the retention of text material. In Experiment 1, using a coherent text, we found no retention benefit of testing compared to a restudy (control) condition. In…

Acute Exercise Improves Motor Memory Consolidation in Preadolescent Children

PubMed Central

Lundbye-Jensen, Jesper; Skriver, Kasper; Nielsen, Jens B.; Roig, Marc

2017-01-01

Objective: The ability to acquire new motor skills is essential both during childhood and later in life. Recent studies have demonstrated that an acute bout of exercise can improve motor memory consolidation in adults. The objective of the present study was to investigate whether acute exercise protocols following motor skill practice in a school setting can also improve long-term retention of motor memory in preadolescent children. Methods: Seventy-seven pre-adolescent children (age 10.5 ± 0.75 (SD)) participated in the study. Prior to the main experiment age, BMI, fitness status and general physical activity level was assessed in all children and they were then randomly allocated to three groups. All children practiced a visuomotor tracking task followed by 20 min of rest (CON), high intensity intermittent floorball (FLB) or running (RUN) with comparable exercise intensity and duration for exercise groups. Delayed retention of motor memory was assessed 1 h, 24 h and 7 days after motor skill acquisition. Results: During skill acquisition, motor performance improved significantly to the immediate retention test with no differences between groups. One hour following skill acquisition, motor performance decreased significantly for RUN. Twenty-four hours following skill acquisition there was a tendency towards improved performance for FLB but no significant effects. Seven days after motor practice however, both FLB and RUN performed better when compared to their immediate retention test indicating significant offline gains. This effect was not observed for CON. In contrast, 7 days after motor practice, retention of motor memory was significantly better for FLB and RUN compared to CON. No differences were observed when comparing FLB and RUN. Conclusions: Acute intense intermittent exercise performed immediately after motor skill acquisition facilitates long-term motor memory in pre-adolescent children, presumably by promoting memory consolidation. The results also demonstrate that the effects can be accomplished in a school setting. The positive effect of both a team game (i.e., FLB) and running indicates that the observed memory improvements are determined to a larger extent by physiological factors rather than the types of movements performed during the exercise protocol. PMID:28473761

Initial characterization of a low-molecular-weight factor enhancing the checkpoint response.

PubMed

Fan, Xiaoxiang; Cheong, Nge; Iliakis, George

2010-10-01

In higher eukaryotes, DNA double-strand breaks (DSBs) induced by ionizing radiation activate checkpoints that delay progression through the cell cycle. Compared to delays in other phases of the cell cycle, delays induced in G(2) are longer and frequently correlate with resistance to killing by radiation. Therefore, modulation of the G(2) checkpoint offers a means to modulate cellular radiosensitivity. Although compounds are known that reduce the G(2) checkpoint and act as radiosensitizers, compounds enhancing this checkpoint have not been reported. Here we summarize evidence for a factor with such properties. We show that a highly radioresistant rat embryo fibroblast (REF) cell line displays a strong G(2) checkpoint partly as a result of a factor excreted into the growth medium by nonirradiated cells. Various tests indicate that this G(2)-arrest modulating activity (GAMA) is a small molecule showing detectable retention only after passing through filters with a molecular weight cutoff limit of less than 1,000 Da. GAMA is heat stable and resistant to treatment with proteases or nucleases. Electroelution tests show that GAMA is uncharged at neutral pH, a result that is in agreement with the observed failure to bind S- or Q-Sepharose. Investigations on the mechanism of GAMA function indicate ligand-receptor interactions and allow the classification of cells as producers, responders or both. Compounds with properties such as those of GAMA bridge intercellular communication with the DNA damage response and may function as radioprotectors.

Prefrontocortical dopamine loss in rats delays long-term extinction of contextual conditioned fear, and reduces social interaction without affecting short-term social interaction memory.

PubMed

Fernandez Espejo, Emilio

2003-03-01

Prefrontal dopamine loss delays extinction of cued fear conditioning responses, but its role in contextual fear conditioning has not been explored. Medial prefrontal lesions also enhance social interaction in rats, but the role of prefrontal dopamine loss on social interaction memory is not known. Besides, a role for subcortical accumbal dopamine on mnesic changes after prefrontal dopamine manipulation has been proposed but not explored. The objective was to study the involvement of dopaminergic neurotransmission in the medial prefrontal cortex (mPFC) and nucleus accumbens in two mnesic tasks: contextual fear conditioning and social interaction memory. For contextual fear conditioning, short- and long-term freezing responses after an electric shock were studied, as well as extinction retention. Regarding social interaction memory, the recognition of a juvenile, a very sensitive short-term memory test, was used. Dopamine loss was carried out by injection of 6-hydroxydopamine, and postmortem catecholamine levels were analyzed by high-performance liquid chromatography. Prefrontocortical dopamine loss (>76%) led to a reactive enhancement of accumbal dopamine content (p<0.01), supporting the hypothesis that a hyperdopaminergic tone emerges in the nucleus accumbens after prefrontocortical dopamine loss. In lesioned rats, long-term extinction of contextual fear conditioning was significantly delayed and extinction retention was impaired without changes in acquisition and short-term contextual fear conditioning and, on the other hand, acquisition and short-term social interaction memory were not affected, although time spent on social interaction was significantly reduced. Added dopamine loss in the nucleus accumbens (>76%) did not alter these behavioral changes. In summary, the results of the present study indicate that the dopaminergic network in the mPFC (but not in the nucleus accumbens) coordinates the normal long-term extinction of contextual fear conditioning responses without affecting their acquisition, and it is involved in time spent on social interaction, but not acquisition and short-term social interaction memory.

Molecular Mechanisms Controlling GLUT4 Intracellular Retention

PubMed Central

Blot, Vincent

2008-01-01

In basal adipocytes, glucose transporter 4 (GLUT4) is sequestered intracellularly by an insulin-reversible retention mechanism. Here, we analyze the roles of three GLUT4 trafficking motifs (FQQI, TELEY, and LL), providing molecular links between insulin signaling, cellular trafficking machinery, and the motifs in the specialized trafficking of GLUT4. Our results support a GLUT4 retention model that involves two linked intracellular cycles: one between endosomes and a retention compartment, and the other between endosomes and specialized GLUT4 transport vesicles. Targeting of GLUT4 to the former is dependent on the FQQI motif and its targeting to the latter is dependent on the TELEY motif. These two motifs act independently in retention, with the TELEY-dependent step being under the control of signaling downstream of the AS160 rab GTPase activating protein. Segregation of GLUT4 from endosomes, although positively correlated with the degree of basal retention, does not completely account for GLUT4 retention or insulin-responsiveness. Mutation of the LL motif slows return to basal intracellular retention after insulin withdrawal. Knockdown of clathrin adaptin protein complex-1 (AP-1) causes a delay in the return to intracellular retention after insulin withdrawal. The effects of mutating the LL motif and knockdown of AP-1 were not additive, establishing that AP-1 regulation of GLUT4 trafficking requires the LL motif. PMID:18550797

Prose memory deficits associated with schizophrenia.

PubMed

Lee, Tatia M C; Chan, Michelle W C; Chan, Chetwyn C H; Gao, Junling; Wang, Kai; Chen, Eric Y H

2006-01-31

Memory of contextual information is essential to one's quality of living. This study investigated if the different components of prose memory, across three recall conditions: first learning trial immediate recall, fifth learning trial immediate recall, and 30-min delayed recall, are differentially impaired in people with schizophrenia, relative to healthy controls. A total of 39 patients with schizophrenia and 39 matched healthy controls were recruited. Their prose memory, in terms of recall accuracy, temporal sequence, recognition accuracy and false positives, commission of distortions, and rates of learning, forgetting, and retention were tested and compared. After controlling for the level of intelligence and depression, the patients with schizophrenia were found to commit more distortions. Furthermore, they performed poorer on recall accuracy and temporal sequence accuracy only during the first initial immediate recall. On the other hand, the rates of forgetting/retention and recognition accuracy were comparable between the two groups. These findings suggest that people with schizophrenia could be benefited by repeated exposure to the materials to be remembered. These results may have important implications for rehabilitation of verbal declarative memory deficits in schizophrenia.

Climatic variability and its role in regulating C, N and P retention in the James River Estuary

NASA Astrophysics Data System (ADS)

Bukaveckas, Paul A.; Beck, Michael; Devore, Dana; Lee, William M.

2018-05-01

Transformations and retention of C, N and P inputs to estuaries are subject to external factors such as discharge-driven variation in loading rates, and internal processes regulating biogeochemical cycles. We used an 8-year time series of finely resolved (monthly) mass balances for the tidal freshwater segment of the James River Estuary to assess the influence of discharge and temperature on C, N and P retention. Peak export and retention of organic, likely particulate, fractions occurred in months of highest discharge. With increasing discharge we observed higher mass retention, greater proportional retention (in relation to inputs) and more selective retention (with P retained preferentially over N and C). DIN retention was strongly influenced by water temperature with 10-fold high retention occurring at high (>20 °C) vs. low (<15 °C) water temperature at corresponding discharge. Our findings suggest that rising temperatures will have a greater effect on the retention of N than P because a greater proportion of the total N delivered to estuaries is in dissolved inorganic form, and therefore subject to temperature dependent rates of biological assimilation and denitrification. By contrast, the bulk of the P load was in particulate form, which is retained via sediment trapping, and not appreciably affected by water temperature. The tidal freshwater estuary was an important site for nutrient removal where the accumulation of N- and P- rich materials may delay recovery in response to nutrient load reductions.

Delay and probability discounting among payday and title loan recipients.

PubMed

Mahoney, Colin T; Lawyer, Steven R

2016-04-01

Payday and title loans are short-term loans associated with significant economic impact. Behavioral theories of impulsive choice may provide insight into behavioral processes that underlie the propensity to take out payday and title loans. Adults between the ages of 18 and 30 recruited from the community completed delay and probability discounting tasks for hypothetical money as well as measures of substance use. Patterns of discounting were characterized using a hyperbolic decay model and area under the curve. Participants who took out a payday and/or title loan in the past (n=41) exhibited more impulsive choice patterns on the delay discounting task than did those who did not (n=255). Substance use mediated this relationship between payday and title loan retention and delay discounting. These findings suggest potentially important relationships between payday/title loan borrowing, substance use, and delay discounting. Copyright © 2016 Elsevier B.V. All rights reserved.

Benefits from retrieval practice are greater for students with lower working memory capacity.

PubMed

Agarwal, Pooja K; Finley, Jason R; Rose, Nathan S; Roediger, Henry L

2017-07-01

We examined the effects of retrieval practice for students who varied in working memory capacity as a function of the lag between study of material and its initial test, whether or not feedback was given after the test, and the retention interval of the final test. We sought to determine whether a blend of these conditions exists that maximises benefits from retrieval practice for lower and higher working memory capacity students. College students learned general knowledge facts and then restudied the facts or were tested on them (with or without feedback) at lags of 0-9 intervening items. Final cued recall performance was better for tested items than for restudied items after both 10 minutes and 2 days, particularly for longer study-test lags. Furthermore, on the 2-day delayed test the benefits from retrieval practice with feedback were significantly greater for students with lower working memory capacity than for students with higher working memory capacity (r = -.42). Retrieval practice may be an especially effective learning strategy for lower ability students.

The retention and disruption of color information in human short-term visual memory.

PubMed

Nemes, Vanda A; Parry, Neil R A; Whitaker, David; McKeefry, Declan J

2012-01-27

Previous studies have demonstrated that the retention of information in short-term visual perceptual memory can be disrupted by the presentation of masking stimuli during interstimulus intervals (ISIs) in delayed discrimination tasks (S. Magnussen & W. W. Greenlee, 1999). We have exploited this effect in order to determine to what extent short-term perceptual memory is selective for stimulus color. We employed a delayed hue discrimination paradigm to measure the fidelity with which color information was retained in short-term memory. The task required 5 color normal observers to discriminate between spatially non-overlapping colored reference and test stimuli that were temporally separated by an ISI of 5 s. The points of subjective equality (PSEs) on the resultant psychometric matching functions provided an index of performance. Measurements were made in the presence and absence of mask stimuli presented during the ISI, which varied in hue around the equiluminant plane in DKL color space. For all reference stimuli, we found a consistent mask-induced, hue-dependent shift in PSE compared to the "no mask" conditions. These shifts were found to be tuned in color space, only occurring for a range of mask hues that fell within bandwidths of 29-37 deg. Outside this range, masking stimuli had little or no effect on measured PSEs. The results demonstrate that memory masking for color exhibits selectivity similar to that which has already been demonstrated for other visual attributes. The relatively narrow tuning of these interference effects suggests that short-term perceptual memory for color is based on higher order, non-linear color coding. © ARVO

Developing a hippocampal neural prosthetic to facilitate human memory encoding and recall.

PubMed

Hampson, Robert E; Song, Dong; Robinson, Brian S; Fetterhoff, Dustin; Dakos, Alexander S; Roeder, Brent M; She, Xiwei; Wicks, Robert T; Witcher, Mark R; Couture, Daniel E; Laxton, Adrian W; Munger-Clary, Heidi; Popli, Gautam; Sollman, Myriam J; Whitlow, Christopher T; Marmarelis, Vasilis Z; Berger, Theodore W; Deadwyler, Sam A

2018-06-01

We demonstrate here the first successful implementation in humans of a proof-of-concept system for restoring and improving memory function via facilitation of memory encoding using the patient's own hippocampal spatiotemporal neural codes for memory. Memory in humans is subject to disruption by drugs, disease and brain injury, yet previous attempts to restore or rescue memory function in humans typically involved only nonspecific, modulation of brain areas and neural systems related to memory retrieval. We have constructed a model of processes by which the hippocampus encodes memory items via spatiotemporal firing of neural ensembles that underlie the successful encoding of short-term memory. A nonlinear multi-input, multi-output (MIMO) model of hippocampal CA3 and CA1 neural firing is computed that predicts activation patterns of CA1 neurons during the encoding (sample) phase of a delayed match-to-sample (DMS) human short-term memory task. MIMO model-derived electrical stimulation delivered to the same CA1 locations during the sample phase of DMS trials facilitated short-term/working memory by 37% during the task. Longer term memory retention was also tested in the same human subjects with a delayed recognition (DR) task that utilized images from the DMS task, along with images that were not from the task. Across the subjects, the stimulated trials exhibited significant improvement (35%) in both short-term and long-term retention of visual information. These results demonstrate the facilitation of memory encoding which is an important feature for the construction of an implantable neural prosthetic to improve human memory.

Developing a hippocampal neural prosthetic to facilitate human memory encoding and recall

NASA Astrophysics Data System (ADS)

Hampson, Robert E.; Song, Dong; Robinson, Brian S.; Fetterhoff, Dustin; Dakos, Alexander S.; Roeder, Brent M.; She, Xiwei; Wicks, Robert T.; Witcher, Mark R.; Couture, Daniel E.; Laxton, Adrian W.; Munger-Clary, Heidi; Popli, Gautam; Sollman, Myriam J.; Whitlow, Christopher T.; Marmarelis, Vasilis Z.; Berger, Theodore W.; Deadwyler, Sam A.

2018-06-01

Objective. We demonstrate here the first successful implementation in humans of a proof-of-concept system for restoring and improving memory function via facilitation of memory encoding using the patient’s own hippocampal spatiotemporal neural codes for memory. Memory in humans is subject to disruption by drugs, disease and brain injury, yet previous attempts to restore or rescue memory function in humans typically involved only nonspecific, modulation of brain areas and neural systems related to memory retrieval. Approach. We have constructed a model of processes by which the hippocampus encodes memory items via spatiotemporal firing of neural ensembles that underlie the successful encoding of short-term memory. A nonlinear multi-input, multi-output (MIMO) model of hippocampal CA3 and CA1 neural firing is computed that predicts activation patterns of CA1 neurons during the encoding (sample) phase of a delayed match-to-sample (DMS) human short-term memory task. Main results. MIMO model-derived electrical stimulation delivered to the same CA1 locations during the sample phase of DMS trials facilitated short-term/working memory by 37% during the task. Longer term memory retention was also tested in the same human subjects with a delayed recognition (DR) task that utilized images from the DMS task, along with images that were not from the task. Across the subjects, the stimulated trials exhibited significant improvement (35%) in both short-term and long-term retention of visual information. Significance. These results demonstrate the facilitation of memory encoding which is an important feature for the construction of an implantable neural prosthetic to improve human memory.

Unimodal and crossmodal working memory representations of visual and kinesthetic movement trajectories.

PubMed

Seemüller, Anna; Fiehler, Katja; Rösler, Frank

2011-01-01

The present study investigated whether visual and kinesthetic stimuli are stored as multisensory or modality-specific representations in unimodal and crossmodal working memory tasks. To this end, angle-shaped movement trajectories were presented to 16 subjects in delayed matching-to-sample tasks either visually or kinesthetically during encoding and recognition. During the retention interval, a secondary visual or kinesthetic interference task was inserted either immediately or with a delay after encoding. The modality of the interference task interacted significantly with the encoding modality. After visual encoding, memory was more impaired by a visual than by a kinesthetic secondary task, while after kinesthetic encoding the pattern was reversed. The time when the secondary task had to be performed interacted with the encoding modality as well. For visual encoding, memory was more impaired, when the secondary task had to be performed at the beginning of the retention interval. In contrast, memory after kinesthetic encoding was more affected, when the secondary task was introduced later in the retention interval. The findings suggest that working memory traces are maintained in a modality-specific format characterized by distinct consolidation processes that take longer after kinesthetic than after visual encoding. Copyright © 2010 Elsevier B.V. All rights reserved.

Human area MT+ shows load-dependent activation during working memory maintenance with continuously morphing stimulation.

PubMed

Galashan, Daniela; Fehr, Thorsten; Kreiter, Andreas K; Herrmann, Manfred

2014-07-11

Initially, human area MT+ was considered a visual area solely processing motion information but further research has shown that it is also involved in various different cognitive operations, such as working memory tasks requiring motion-related information to be maintained or cognitive tasks with implied or expected motion.In the present fMRI study in humans, we focused on MT+ modulation during working memory maintenance using a dynamic shape-tracking working memory task with no motion-related working memory content. Working memory load was systematically varied using complex and simple stimulus material and parametrically increasing retention periods. Activation patterns for the difference between retention of complex and simple memorized stimuli were examined in order to preclude that the reported effects are caused by differences in retrieval. Conjunction analysis over all delay durations for the maintenance of complex versus simple stimuli demonstrated a wide-spread activation pattern. Percent signal change (PSC) in area MT+ revealed a pattern with higher values for the maintenance of complex shapes compared to the retention of a simple circle and with higher values for increasing delay durations. The present data extend previous knowledge by demonstrating that visual area MT+ presents a brain activity pattern usually found in brain regions that are actively involved in working memory maintenance.

Cognitive effects of methylphenidate and levodopa in healthy volunteers.

PubMed

Linssen, A M W; Sambeth, A; Vuurman, E F P M; Riedel, W J

2014-02-01

Our previous study showed enhanced declarative memory consolidation after acute methylphenidate (MPH) administration. The primary aim of the current study was to investigate the duration of this effect. Secondary, the dopaminergic contribution of MPH effects, the electrophysiological correlates of declarative memory, and the specificity of memory enhancing effects of MPH to declarative memory were assessed. Effects of 40 mg of MPH on memory performance were compared to 100mg of levodopa (LEV) in a placebo-controlled crossover study with 30 healthy volunteers. Memory performance testing included a word learning test, the Sternberg memory scanning task, a paired associates learning task, and a spatial working memory task. During the word learning test, event-related brain potentials (ERPs) were measured. MPH failed to enhance retention of words at a 30 min delay, but it improved 24 h delayed memory recall relative to PLA and LEV. Furthermore, during encoding, the P3b and P600 ERP latencies were prolonged and the P600 amplitude was larger after LEV compared to PLA and MPH. MPH speeded response times on the Sternberg Memory Scanning task and improved performance on the Paired Associates Learning task, relative to LEV, but not PLA. Performance on the Spatial working memory task was not affected by the treatments. These findings suggest that MPH and LEV might have opposite effects on memory. © 2013 Published by Elsevier B.V. and ECNP.

Research on the effect of rainfall flood regulation and control of wetland park based on SWMM model—a case study of wetland park in Yuanjia village, Qishan county, Shaanxi province

NASA Astrophysics Data System (ADS)

Xu, Da; Liu, Yijie

2018-02-01

Taking the wetland park of Yuan Village in Qishan County of Shaanxi Province as the research object, this paper makes a reasonable generalization of the study area, and establishes two models of low impact development (LID) and traditional development in the park. Meantime, rainwater in the surrounding built up area is introduced to into the park for digestion. SWMM model is used to simulate the variation of the total runoff, peak flow and peak time of two development models in Wetland Park under one-hour rainfall at different recurrence periods.The runoff control effect in each single LID facility in the one-hour rainfall once during five years in the built-up area is simulated. The simulation results show that the SWMM model can not only quantify the runoff reduction effect of different LID facilities, but also provide theoretical basis and data support for the urban rainfall flood problem. LID facilities have effects on runoff reduction and peak delay. However, the combined LID facility has obvious advantages for the peak time delay and peak flow control. A single LID facility is more efficient in a single runoff volume control. The order of runoff reduction by various LID facilities is as follows: Rain garden>combined LID facility> vegetative swale> bio-retention cell > permeable pavement. The order of peak time delay effect by the LID facilities is as follows: combined LID facility> Rain garden> vegetative swale> bio-retention cell > permeable pavement. The order of peak flow reduction efficiency by various LID facilities is: combined LID facility> Rain garden> bio-retention cell > vegetative swale> permeable pavement.

Traction-assisted Internal Negative Pressure Wound Therapy With Bridging Retention Sutures to Facilitate Staged Closure of High-risk Wounds Under Tension.

PubMed

DeFazio, Michael V; Economides, James M; Anghel, Ersilia L; Mathis, Ryan K; Barbour, John R; Attinger, Christopher E

2017-10-01

Loss of domain often complicates attempts at delayed wound closure in regions of high tension. Wound temporization with traction-assisted internal negative pressure wound therapy (NPWT), using bridging retention sutures, can minimize the effects of edema and elastic recoil that contribute to progressive tissue retraction over time. The investigators evaluated the safety and efficacy of this technique for complex wound closure. Between May 2015 and November 2015, 18 consecutive patients underwent staged reconstruction of complex and/or contaminated soft tissue defects utilizing either conventional NPWT or modified NPWT with instillation and continuous dermatotraction via bridging retention sutures. Instillation of antimicrobial solution was reserved for wounds containing infected/exposed hardware or prosthetic devices. Demographic data, wound characteristics, reconstructive outcomes, and complications were reviewed retrospectively. Eighteen wounds were treated with traction-assisted internal NPWT using the conventional (n = 11) or modified instillation (n = 7) technique. Defects involved the lower extremity (n = 14), trunk (n = 3), and proximal upper extremity (n = 1), with positive cultures identified in 12 wounds (67%). Therapy continued for 3 to 8 days (mean, 4.3 days), resulting in an average wound surface area reduction of 78% (149 cm² vs. 33 cm²) at definitive closure. Seventeen wounds (94%) were closed directly, whereas the remaining defect required coverage with a local muscle flap and skin graft. At final follow-up (mean, 12 months), 89% of wounds remained closed. In 2 patients with delayed, recurrent periprosthetic infection (mean, 7.5 weeks), serial debridement/hardware removal mandated free tissue transfer for composite defect reconstruction. Traction-assisted internal NPWT provides a safe and effective alternative to reduce wound burden and facilitate definitive closure in cases where delayed reconstruction of high-tension wounds is planned.

49 CFR 199.111 - Retention of samples and additional testing.

Code of Federal Regulations, 2011 CFR

2011-10-01

... SAFETY DRUG AND ALCOHOL TESTING Drug Testing § 199.111 Retention of samples and additional testing. (a... other than the unauthorized use of a prohibited drug, and if timely additional testing is requested by... 49 Transportation 3 2011-10-01 2011-10-01 false Retention of samples and additional testing. 199...

49 CFR 199.111 - Retention of samples and additional testing.

Code of Federal Regulations, 2013 CFR

2013-10-01

... SAFETY DRUG AND ALCOHOL TESTING Drug Testing § 199.111 Retention of samples and additional testing. (a... other than the unauthorized use of a prohibited drug, and if timely additional testing is requested by... 49 Transportation 3 2013-10-01 2013-10-01 false Retention of samples and additional testing. 199...

49 CFR 199.111 - Retention of samples and additional testing.

Code of Federal Regulations, 2012 CFR

2012-10-01

... SAFETY DRUG AND ALCOHOL TESTING Drug Testing § 199.111 Retention of samples and additional testing. (a... other than the unauthorized use of a prohibited drug, and if timely additional testing is requested by... 49 Transportation 3 2012-10-01 2012-10-01 false Retention of samples and additional testing. 199...

49 CFR 199.111 - Retention of samples and additional testing.

Code of Federal Regulations, 2010 CFR

2010-10-01

... SAFETY DRUG AND ALCOHOL TESTING Drug Testing § 199.111 Retention of samples and additional testing. (a... other than the unauthorized use of a prohibited drug, and if timely additional testing is requested by... 49 Transportation 3 2010-10-01 2010-10-01 false Retention of samples and additional testing. 199...

49 CFR 199.111 - Retention of samples and additional testing.

Code of Federal Regulations, 2014 CFR

2014-10-01

... SAFETY DRUG AND ALCOHOL TESTING Drug Testing § 199.111 Retention of samples and additional testing. (a... other than the unauthorized use of a prohibited drug, and if timely additional testing is requested by... 49 Transportation 3 2014-10-01 2014-10-01 false Retention of samples and additional testing. 199...

The hydrological behaviour of extensive and intensive green roofs in a dry climate.

PubMed

Razzaghmanesh, M; Beecham, S

2014-11-15

This paper presents the results of a hydrological investigation of four medium scale green roofs that were set up at the University of South Australia. In this study, the potential of green roofs as a source control device was investigated over a 2 year period using four medium size green roof beds comprised of two growth media types and two media depths. During the term of this study, 226 rainfall events were recorded and these were representative of the Adelaide climate. In general, there were no statistically significant differences between the rainfall and runoff parameters for the intensive and extensive beds except for peak attenuation and peak runoff delay, for which higher values were recorded in the intensive beds. Longer dry periods generally resulted in higher retention coefficients and higher retention was also recorded in warmer seasons. The average retention coefficient for intensive systems (89%) was higher than for extensive systems (74%). It was shown that rainfall depth, intensity, duration and also average dry weather period between events can change the retention performance and runoff volume of the green roofs. Comparison of green and simulated conventional roofs indicated that the former were able to mitigate the peak of runoff and could delay the start of runoff. These characteristics are important for most source control measures. The recorded rainfall and runoff data displayed a non-linear relationship. Also, the results indicated that continuous time series modelling would be a more appropriate technique than using peak rainfall intensity methods for green roof design and simulation. Copyright © 2014 Elsevier B.V. All rights reserved.

The Comparative Effects of Prediction/Discussion-Based Learning Cycle, Conceptual Change Text, and Traditional Instructions on Student Understanding of Genetics

NASA Astrophysics Data System (ADS)

Yilmaz, Diba; Tekkaya, Ceren; Sungur, Semra

2011-03-01

The present study examined the comparative effects of a prediction/discussion-based learning cycle, conceptual change text (CCT), and traditional instructions on students' understanding of genetics concepts. A quasi-experimental research design of the pre-test-post-test non-equivalent control group was adopted. The three intact classes, taught by the same science teacher, were randomly assigned as prediction/discussion-based learning cycle class (N = 30), CCT class (N = 25), and traditional class (N = 26). Participants completed the genetics concept test as pre-test, post-test, and delayed post-test to examine the effects of instructional strategies on their genetics understanding and retention. While the dependent variable of this study was students' understanding of genetics, the independent variables were time (Time 1, Time 2, and Time 3) and mode of instruction. The mixed between-within subjects analysis of variance revealed that students in both prediction/discussion-based learning cycle and CCT groups understood the genetics concepts and retained their knowledge significantly better than students in the traditional instruction group.

Comparison of Verbal Learning and Memory in Children with Heavy Prenatal Alcohol Exposure or Attention-Deficit/Hyperactivity Disorder

PubMed Central

Crocker, Nicole; Vaurio, Linnea; Riley, Edward P.; Mattson, Sarah N.

2011-01-01

Background Children with fetal alcohol spectrum disorders (FASD) have deficits in verbal learning and recall. However, the specificity of these deficits has not been adequately tested. In the current study, verbal learning and memory performance of children with heavy prenatal alcohol exposure was compared to children with attention-deficit/hyperactivity disorder (ADHD), a disorder commonly seen in alcohol-exposed children. Methods Performance on the California Verbal Learning Test – Children's Version (CVLT-C) was examined in three groups of children (N=22/group): (1) heavy prenatal alcohol exposure and ADHD (ALC), (2) nonexposed with ADHD (ADHD), and (3) nonexposed typically developing (CON). Groups were matched on age, sex, race, ethnicity, handedness, and socioeconomic status. Results Group differences were noted on learning trials (CON > ADHD > ALC). On the delayed recall trial, CON children performed better than both clinical groups, who did not differ from each other. Children in the ALC group demonstrated poorer recognition than children in the CON and ADHD groups, who did not differ from each other. Marginally significant group differences were noted on retention of previously learned material. Post hoc analyses indicated that ADHD children showed worse retention relative to the CON group, whereas retention in the ALC children remained intact. Conclusions These data suggest that children with heavy prenatal alcohol exposure and nonexposed children with ADHD show differential patterns of deficit on the CVLT-C. Performance of alcohol-exposed children reflects inefficient encoding of verbal material, whereas performance of the ADHD group may be better characterized by a deficit in retrieval of learned material. Differences noted between clinical groups add to a growing neurobehavioral profile of FASD that may aid in differential diagnosis. PMID:21410480

Semen characteristics after overnight shipping: preservation of sperm concentrations, HspA2 ratios, CK activity, cytoplasmic retention, chromatin maturity, DNA integrity, and sperm shape.

PubMed

Huszar, Gabor; Celik-Ozenci, Ciler; Cayli, Sevil; Kovacs, Tamas; Vigue, Lynne; Kovanci, Ertug

2004-01-01

We tested several approaches that can be used to preserve sperm attributes and the objective biochemical markers of sperm maturity and function for assessment in a remote centralized laboratory after overnight shipping of semen samples. Addition of phenyl-methyl-sulfonyl-fluoride (PMSF) to a final concentration of 20 microg/mL semen at 4 degrees C has preserved sperm concentrations and HspA2 isoform ratios, even at room temperature, simulating a shipping delay in moderate ambient temperatures. Regarding the attributes of individual spermatozoa, the patterns of CK-immunocytochemistry (demonstrates cytoplasmic retention in diminished-maturity spermatozoa); aniline blue staining pattern (tests chromatin maturity); sperm shape assessed by both Kruger strict morphology and computer assisted morphometry; and sperm DNA integrity, as tested by DNA nick translation, all remained unchanged. Thus, the PMSF-4 degrees C conditions preserved sperm concentrations and the cytoplasmic and nuclear biomarkers of sperm cellular maturity and function for next-day analysis. This shipping method will facilitate the early detection of subtle changes in semen quality that can affect sperm function, even when there has been no decline in sperm concentrations to signal possible toxic effects. Furthermore, sample preservation will enable investigators to evaluate semen for toxicology studies and for diagnosis of male infertility from remote locations. Home collection of semen should enhance study participation, and semen assessment in centralized laboratories will address concerns regarding interlaboratory variations and quality control.

Effect of Sustained Postnatal Systemic Inflammation on Hippocampal Volume and Function in Mice

PubMed Central

Malaeb, Shadi N.; Davis, Jonathan M.; Pinz, Ilka M.; Newman, Jennifer L.; Dammann, Olaf; Rios, Maribel

2014-01-01

Background Premature infants are at risk for persistent neurodevelopmental impairment. Children born preterm often exhibit reduced hippocampal volumes that correlate with deficits in working memory. Perinatal inflammation is associated with preterm birth and brain abnormalities. Here we examine the effects of postnatal systemic inflammation on the developing hippocampus in mice. Methods Pups received daily intraperitoneal injections of lipopolysaccharide (LPS) or saline between days 3–13. Ex-vivo magnetic resonance imaging (MRI) and microscopic analysis of brain tissue was performed on day 14. Behavioral testing was conducted at 8–9 weeks of age. Results MR and microscopic analysis revealed a 15–20% reduction in hippocampal volume in LPS-treated mice compared to controls. Behavioral testing revealed deficits in hippocampal-related tasks in LPS-treated animals. Adult mice exposed to LPS during the postnatal period were unable to select a novel environment when re-placed within a 1-minute delay, were less able to remember a familiar object after a 1-hour delay and had impaired retention of associative fear learning after 24 hours. Conclusion Systemic inflammation sustained during the postnatal period contributes to reduced hippocampal volume and deficits in hippocampus-dependent working memory. These findings support the novel and emerging concept that sustained systemic inflammation contributes to neurodevelopmental impairment among preterm infants. PMID:25003911

Scale invariance of temporal order discrimination using complex, naturalistic events

PubMed Central

Kwok, Sze Chai; Macaluso, Emiliano

2015-01-01

Recent demonstrations of scale invariance in cognitive domains prompted us to investigate whether a scale-free pattern might exist in retrieving the temporal order of events from episodic memory. We present four experiments using an encoding-retrieval paradigm with naturalistic stimuli (movies or video clips). Our studies show that temporal order judgement retrieval times were negatively correlated with the temporal separation between two events in the movie. This relation held, irrespective of whether temporal distances were on the order of tens of minutes (Exp 1−2) or just a few seconds (Exp 3−4). Using the SIMPLE model, we factored in the retention delays between encoding and retrieval (delays of 24 h, 15 min, 1.5–2.5 s, and 0.5 s for Exp 1–4, respectively) and computed a temporal similarity score for each trial. We found a positive relation between similarity and retrieval times; that is, the more temporally similar two events, the slower the retrieval of their temporal order. Using Bayesian analysis, we confirmed the equivalence of the RT/similarity relation across all experiments, which included a vast range of temporal distances and retention delays. These results provide evidence for scale invariance during the retrieval of temporal order of episodic memories. PMID:25909581

Music enhances verbal episodic memory in Alzheimer's disease.

PubMed

Palisson, Juliette; Roussel-Baclet, Caroline; Maillet, Didier; Belin, Catherine; Ankri, Joël; Narme, Pauline

2015-01-01

Although previous studies suggest that music may facilitate verbal learning in a healthy population, such a mnemonic effect has seldom been investigated in Alzheimer's disease (AD). Moreover, memorization of texts was generally compared when either sung or spoken. In the present study, it was examined whether the benefit observed on verbal learning was specific to music or whether an associative context binding items together led to similar benefits, regardless of the nature of the association. Twelve patients with mild AD and 15 healthy controls learned texts presented with either a musical (sung) or a nonmusical association (spoken associated to a silent movie sequence) or without association (spoken alone). Immediate and delayed (after a 5-min delay) recall was measured. Main results showed that (a) sung texts were better remembered than spoken texts, both immediately and after a retention delay, for both groups; (b) the musical benefit was robust, being observed in most AD patients; (c) the nonmusical association may also facilitate verbal learning but to a lesser extent. A musical association during the encoding stage facilitates learning and retention in AD. Furthermore, this advantage seemed quite specific to music. The results are discussed with respect to the clinical applications in AD; theoretical implications are highlighted to explain the power of music as a mnemonic technique.

Retention of Knowledge following training of students in Basic Trauma Life Support.

PubMed

Lim, K G; Lum, S K; Burud, I A S

2016-12-01

In the course of their undergraduate training at the International Medical University, students receive a Basic Trauma Life Support course. We wanted to test the long-term retention of knowledge (after 16 months) of third year medical students who had received training in Basic Trauma Life Support Method: To assess the retention of knowledge one cohort of students who received the training course were tested again 16 months later using the same 30 question One Best Answer quiz. Seventy-three students who underwent the course sat for the Retention test. The number of students who passed the Retention test was not significantly different from the test taken immediately after the course. The mean scores, 62.5% and 59.5% respectively, were however significantly different. Our study involves a relatively long interval between the course and retention of knowledge test shows encouraging results.

Revealing past memories: proactive interference and ketamine-induced memory deficits.

PubMed

Chrobak, James J; Hinman, James R; Sabolek, Helen R

2008-04-23

Memories of events that occur often are sensitive to interference from memories of similar events. Proactive interference plays an important and often unexamined role in memory testing for spatially and temporally unique events ("episodes"). Ketamine (NMDA receptor antagonist) treatment in humans and other mammals induces a constellation of cognitive deficits, including impairments in working and episodic memory. We examined the effects of the ketamine (2.5-100 mg/kg) on the acquisition, retrieval, and retention of memory in a delayed-match-to-place radial water maze task that can be used to assess proactive interference. Ketamine (2.5-25 mg/kg, i.p.) given 20 min before the sample trial, impaired encoding. The first errors made during the test trial were predominantly to arms located spatially adjacent to the goal arm, suggesting an established albeit weakened representation. Ketamine (25-100 mg/kg) given immediately after the sample trial had no effect on retention. Ketamine given before the test trial impaired retrieval. First errors under the influence of ketamine were predominantly to the goal location of the previous session. Thus, ketamine treatment promoted proactive interference. These memory deficits were not state dependent, because ketamine treatment at both encoding and retrieval only increased the number of errors during the test session. These data demonstrate the competing influence of distinct memory representations during the performance of a memory task in the rat. Furthermore, they demonstrate the subtle disruptive effects of the NMDA antagonist ketamine on both encoding and retrieval. Specifically, ketamine treatment disrupted retrieval by promoting proactive interference from previous episodic representations.

Effects of audio-visual aids on foreign language test anxiety, reading and listening comprehension, and retention in EFL learners.

PubMed

Lee, Shu-Ping; Lee, Shin-Da; Liao, Yuan-Lin; Wang, An-Chi

2015-04-01

This study examined the effects of audio-visual aids on anxiety, comprehension test scores, and retention in reading and listening to short stories in English as a Foreign Language (EFL) classrooms. Reading and listening tests, general and test anxiety, and retention were measured in English-major college students in an experimental group with audio-visual aids (n=83) and a control group without audio-visual aids (n=94) with similar general English proficiency. Lower reading test anxiety, unchanged reading comprehension scores, and better reading short-term and long-term retention after four weeks were evident in the audiovisual group relative to the control group. In addition, lower listening test anxiety, higher listening comprehension scores, and unchanged short-term and long-term retention were found in the audiovisual group relative to the control group after the intervention. Audio-visual aids may help to reduce EFL learners' listening test anxiety and enhance their listening comprehension scores without facilitating retention of such materials. Although audio-visual aids did not increase reading comprehension scores, they helped reduce EFL learners' reading test anxiety and facilitated retention of reading materials.

Impaired Visuospatial Short-Term Memory in Children with ADHD.

PubMed

Narimoto, Tadamasa; Matsuura, Naomi; Hiratani, Michio

2018-01-01

Previous studies provide clear evidence that visuospatial memory performance in children with attention-deficit/hyperactivity disorder (ADHD) is significantly lower than in typically developing children. In the present study, we investigated a major cause of their low performance using a spatial span test. Possibly, inattention resulting from lack of motivation or interest causes their low performance so that they do not correctly encode targets to be remembered. On the other hand, a deficit in temporary maintenance per se may cause their low performance; that is, their inefficient use of rehearsal during a retention interval may lead to memory traces' fast decay. Results in this study indicated that children with ADHD could sustain attention during the encoding phase. Furthermore, their performance at delayed recall was significantly lower than immediate recall, but delayed recall did not affect typically developing children's performance. These results provide evidence for the likelihood that a factor causing children with ADHD difficulty in temporarily maintaining visuospatial information is fast decay of memory traces as a result of inefficient use of rehearsal, not inattention in the encoding phase.

Postharvest shelf-life extension of pink guavas (Psidium guajava L.) using HPMC-based edible surface coatings.

PubMed

Vishwasrao, Chandrahas; Ananthanarayan, Laxmi

2016-04-01

Psidium guajava L. var. 'Lalit' is a perishable fruit with delicate skin which is prone to damage. The objective of this study was to determine the effect of edible coating made up of hydroxypropyl methyl cellulose and palm oil on ripening of guava. Coating solution was applied over fruits and coated fruits were stored at 24 ± 1 °C and 65 ± 5%RH. Changes in fruit colour, texture softening, respiration rate, weight loss, ascorbic acid content, soluble solids, titrable acidity, chlorophyll content, total reducing sugars, total phenolic content were studied during post-harvest ripening. Fruits coated with 1 % of hydroxypropyl methyl cellulose and 0.3 % of palm oil showed significant delay in weight loss, fruit firmness as well as colour change (p < 0.05). Coating delayed the enzyme activities of peroxidase and polyphenol oxidase of the fruit. Results suggest that overall quality of coated fruit was maintained by edible coating formulation extending the shelf life of fruit up to 12 days with appreciable retention of all quality parameters tested.

Immediate versus delayed loading of strategic mini dental implants for the stabilization of partial removable dental prostheses: a patient cluster randomized, parallel-group 3-year trial.

PubMed

Mundt, Torsten; Al Jaghsi, Ahmad; Schwahn, Bernd; Hilgert, Janina; Lucas, Christian; Biffar, Reiner; Schwahn, Christian; Heinemann, Friedhelm

2016-07-30

Acceptable short-term survival rates (>90 %) of mini-implants (diameter < 3.0 mm) are only documented for mandibular overdentures. Sound data for mini-implants as strategic abutments for a better retention of partial removable dental prosthesis (PRDP) are not available. The purpose of this study is to test the hypothesis that immediately loaded mini-implants show more bone loss and less success than strategic mini-implants with delayed loading. In this four-center (one university hospital, three dental practices in Germany), parallel-group, controlled clinical trial, which is cluster randomized on patient level, a total of 80 partially edentulous patients with unfavourable number and distribution of remaining abutment teeth in at least one jaw will receive supplementary min-implants to stabilize their PRDP. The mini-implant are either immediately loaded after implant placement (test group) or delayed after four months (control group). Follow-up of the patients will be performed for 36 months. The primary outcome is the radiographic bone level changes at implants. The secondary outcome is the implant success as a composite variable. Tertiary outcomes include clinical, subjective (quality of life, satisfaction, chewing ability) and dental or technical complications. Strategic implants under an existing PRDP are only documented for standard-diameter implants. Mini-implants could be a minimal invasive and low cost solution for this treatment modality. The trial is registered at Deutsches Register Klinischer Studien (German register of clinical trials) under DRKS-ID: DRKS00007589 ( www.germanctr.de ) on January 13(th), 2015.

Reduction of the misinformation effect by arousal induced after learning.

PubMed

English, Shaun M; Nielson, Kristy A

2010-11-01

Misinformation introduced after events have already occurred causes errors in later retrieval. Based on literature showing that arousal induced after learning enhances delayed retrieval, we investigated whether post-learning arousal can reduce the misinformation effect. 251 participants viewed four short film clips, each followed by a retention test, which for some participants included misinformation. Afterward, participants viewed another film clip that was either arousing or neutral. One week later, the arousal group recognized significantly more veridical details and endorsed significantly fewer misinformation items than the neutral group. The findings suggest that arousal induced after learning reduced source confusion, allowing participants to better retrieve accurate details and to better reject misinformation. Copyright © 2010 Elsevier B.V. All rights reserved.

Retrieval Practice and Spacing Effects in Young and Older Adults: An Examination of the Benefits of Desirable Difficulty

PubMed Central

Maddox, Geoffrey B.; Balota, David A.

2015-01-01

The present study examined how the function relating continued retrieval practice (e.g., 1, 3, or 5 tests) and long-term memory retention is modulated by desirable difficulty (Bjork, 1994). Of particular interest was how retrieval difficulty differed across young and older adults and across manipulations of lag (Experiment 1) and spacing (Experiment 2). To extend on previous studies, acquisition phase response latency was used as a proxy for retrieval difficulty, and analysis of final test performance was conditionalized on acquisition phase retrieval success to more directly examine the influence of desirable difficulty on retention. Results from Experiment 1 revealed that continued testing in the short lag condition led to consistent increases in retention, whereas continued testing in the long lag condition led to increasingly smaller benefits in retention for both age groups. Results from Experiment 2 revealed that repeated spaced testing enhanced retention relative to taking one spaced test for both age groups; however, repeated massed testing only enhanced retention over taking one test for young adults. Across both experiments, the response latency results were overall consistent with an influence of desirable difficulty on retention. Discussion focuses on the role of desirable difficulty during encoding in producing the benefits of lag, spacing, and testing. PMID:25616776

Similar Comparative Low and High Doses of Deltamethrin and Acetamiprid Differently Impair the Retrieval of the Proboscis Extension Reflex in the Forager Honey Bee (Apis mellifera).

PubMed

Thany, Steeve H; Bourdin, Céline M; Graton, Jérôme; Laurent, Adèle D; Mathé-Allainmat, Monique; Lebreton, Jacques; Questel, Jean-Yves le

2015-09-28

In the present study, the effects of low (10 ng/bee) and high (100 ng/bee) doses of acetamiprid and deltamethrin insecticides on multi-trial learning and retrieval were evaluated in the honey bee Apis mellifera. After oral application, acetamiprid and deltamethrin at the concentrations used were not able to impair learning sessions. When the retention tests were performed 1 h, 6 h, and 24 h after learning, we found a significant difference between bees after learning sessions when drugs were applied 24 h before learning. Deltamethrin-treated bees were found to be more sensitive at 10 ng/bee and 100 ng/bee doses compared to acetamiprid-treated bees, only with amounts of 100 ng/bee and at 6 h and 24 h delays. When insecticides were applied during learning sessions, none of the tested insecticides was able to impair learning performance at 10 ng/bee or 100 ng/bee but retention performance was altered 24 h after learning sessions. Acetamiprid was the only one to impair retrieval at 10 ng/bee, whereas at 100 ng/bee an impairment of retrieval was found with both insecticides. The present results therefore suggest that acetamiprid and deltamethrin are able to impair retrieval performance in the honey bee Apis mellifera.

SeHCAT absorption: a simple test of ileal dysfunction.

PubMed

Fagan, E A; Chadwick, V S; Baird, I M

1983-01-01

A new selenium-labelled synthetic bile salt SeHCAT (taurine conjugate of 23-[75Se]-25-homocholic acid) was assessed as a test of ileal dysfunction in 20 patients with inflammatory bowel disease (IBD). Whole body retention of SeHCAT was compared with tests of vitamin B12 absorption (Schilling test and whole body retention) and the cholylglycine-1-14C breath test and faecal isotope excretion. Clear differentiation, with no overlap was obtained between 10 normal subjects and patients with ileal disease/resection in the SeHCAT 7-day retention results. The Schilling test was more sensitive; enabling discrimination between patients with limited and extensive ileal disease/resection. An unexpected rise in SeHCAT retention was observed in patients with colonic IBD. The 7-day SeHCAT retention is a safe, simple screening test for ileal dysfunction and has practical advantages compared with the Schilling test.

Ambulatory Voice Biofeedback: Relative Frequency and Summary Feedback Effects on Performance and Retention of Reduced Vocal Intensity in the Daily Lives of Participants With Normal Voices

PubMed Central

Mehta, Daryush D.; Sternad, Dagmar; Petit, Robert; Hillman, Robert E.

2017-01-01

Purpose Ambulatory voice biofeedback has the potential to significantly improve voice therapy effectiveness by targeting carryover of desired behaviors outside the therapy session (i.e., retention). This study applies motor learning concepts (reduced frequency and delayed, summary feedback) that demonstrate increased retention to ambulatory voice monitoring for training nurses to talk softer during work hours. Method Forty-eight nurses with normal voices wore the Voice Health Monitor (Mehta, Zañartu, Feng, Cheyne, & Hillman, 2012) for 6 days: 3 baseline days, 1 biofeedback day, 1 short-term retention day, and 1 long-term retention day. Participants were block-randomized into 3 different biofeedback groups: 100%, 25%, and Summary. Performance was measured in terms of compliance time below a participant-specific vocal intensity threshold. Results All participants exhibited a significant increase in compliance time (Cohen's d = 4.5) during biofeedback days compared with baseline days. The Summary feedback group exhibited statistically smaller performance reduction during both short-term (d = 1.14) and long-term (d = 1.04) retention days compared with the 100% feedback group. Conclusions These findings suggest that modifications in feedback frequency and timing affect retention of a modified vocal behavior in daily life. Future work calls for studying the potential beneficial impact of ambulatory voice biofeedback in participants with behaviorally based voice disorders. PMID:28329366

Medial Auditory Thalamus Inactivation Prevents Acquisition and Retention of Eyeblink Conditioning

ERIC Educational Resources Information Center

Halverson, Hunter E.; Poremba, Amy; Freeman, John H.

2008-01-01

The auditory conditioned stimulus (CS) pathway that is necessary for delay eyeblink conditioning was investigated using reversible inactivation of the medial auditory thalamic nuclei (MATN) consisting of the medial division of the medial geniculate (MGm), suprageniculate (SG), and posterior intralaminar nucleus (PIN). Rats were given saline or…

75 FR 39003 - SAFRA Act Payments to Loan Servicers for Job Retention

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-07

... obtain this document in an accessible format (e.g., braille, large print, audiotape, or computer diskette... Executive Order 12866 and its overall requirement of reducing regulatory burden that might result from these.../index.html . Waiver of Rulemaking and Delayed Effective Date Under the Administrative Procedure Act (APA...

Learning effectiveness: A comparative study to measure effectiveness of webcasting in success of students in an introductory computer science class

NASA Astrophysics Data System (ADS)

Ghyam, Massoud

This study investigates if providing delayed webcast of college lectures would improve the retention of students enrolled in an introductory computer science class over a span of six semesters. The population for this study was undergraduate engineering students enrolled in the same course at a major research university in a western state in six different semesters. The same instructor taught all sections of the course, the same textbook and software were used, and the number of lab/teaching assistants were also exactly the same. Assignments and exams were changed but were kept at the same level of difficulty. Some students were enrolled in the courses where webcasting was not utilized as a tool, while others took the same course where delayed webcasting was used. The research question that guided the study was: Will use of the delayed webcast and the availability of the course lectures on line improve students' grades and therefore the success ratio in the Introduction to Computer Science and Programming course? For the purposes of this study successful completion is defined as the number of students who did not drop the course, and who passed the course with a grade of C- or better. Grade improvement of students who completed the course was also examined. Result of the study showed providing delayed webcast of the lectures did not improve retention, but neither did it harm the student's learning. Future study is recommended to include coding for gender and student's field of study.

Cardamom (Elettaria cardamomum) perinatal exposure effects on the development, behavior and biochemical parameters in mice offspring.

PubMed

Abu-Taweel, Gasem Mohammad

2018-01-01

Cardamom is a strong antioxidant plant, so it is called the queen of spices. In the present study, we explored the potentials of cardamom on developmental, learning ability and biochemical parameters of mice offspring. Thirty pregnant mice were allocated to three groups of ten animals in each. Groups Π and Ш received pilsbury's Diet containing 10 and 20% of cardamom (w/w) respectively, whereas Group I used as control. Cardomom was administered from the first day of pregnancy and was continued until post-natal day 15 (PD 15) and thereafter the mothers were switched to plain pilsbury's Diet. During the weaning period, three pups in each litter were color marked from the others, and were subjected to various tests (Physical assessment such body weight and eye opening and hair appearance; the neuromaturation of reflexes like righting, rotating, and cliff avoidance reflexes; learning ability and memory retention; estimation of monoamines neurotransmitters like dopamine and serotonin, non-enzymatic oxidative stress such as TBARS and GSH in forebrain at different ages of pups). The results indicated that the body weight gain was declining significantly. Hair appearance and eyes opening were delayed significantly. Righting, rotating, and cliff avoidance reflexes were delayed in treated animals. Exposure to cardamom led to enhance learning and memory retention as compared to control. Monoamines (DA, 5-HT) and GSH were elevated, whereas TBARS was inhibited significantly. In conclusion, perinatal cardamom exposure enhanced learning and memory as compared to control. Cardamom and its benefit compounds were transported via placenta or/and milk during lactation. Cardamom needs more researches to investigate its benefits on other kinds of behavior.

New semi-quantitative 123I-MIBG estimation method compared with scoring system in follow-up of advanced neuroblastoma: utility of total MIBG retention ratio versus scoring method.

PubMed

Sano, Yuko; Okuyama, Chio; Iehara, Tomoko; Matsushima, Shigenori; Yamada, Kei; Hosoi, Hajime; Nishimura, Tsunehiko

2012-07-01

The purpose of this study is to evaluate a new semi-quantitative estimation method using (123)I-MIBG retention ratio to assess response to chemotherapy for advanced neuroblastoma. Thirteen children with advanced neuroblastoma (International Neuroblastoma Risk Group Staging System: stage M) were examined for a total of 51 studies with (123)I-MIBG scintigraphy (before and during chemotherapy). We proposed a new semi-quantitative method using MIBG retention ratio (count obtained with delayed image/count obtained with early image with decay correction) to estimate MIBG accumulation. We analyzed total (123)I-MIBG retention ratio (TMRR: total body count obtained with delayed image/total body count obtained with early image with decay correction) and compared with a scoring method in terms of correlation with tumor markers. TMRR showed significantly higher correlations with urinary catecholamine metabolites before chemotherapy (VMA: r(2) = 0.45, P < 0.05, HVA: r(2) = 0.627, P < 0.01) than MIBG score (VMA: r(2) = 0.19, P = 0.082, HVA: r(2) = 0.25, P = 0.137). There were relatively good correlations between serial change of TMRR and those of urinary catecholamine metabolites (VMA: r(2) = 0.274, P < 0.001, HVA: r(2) = 0.448, P < 0.0001) compared with serial change of MIBG score and those of tumor markers (VMA: r(2) = 0.01, P = 0.537, HVA: 0.084, P = 0.697) during chemotherapy for advanced neuroblastoma. TMRR could be a useful semi-quantitative method for estimating early response to chemotherapy of advanced neuroblastoma because of its high correlation with urine catecholamine metabolites.

Linking and Retaining HIV Patients in Care: The Importance of Provider Attitudes and Behaviors

PubMed Central

Herwehe, Jane; Murtaza-Rossini, Michelli; Reine, Petera; Cuffie, Damien; Gruber, DeAnn; Kaiser, Michael

2013-01-01

Abstract Retention in HIV treatment may reduce morbidity and mortality, as well as slow the epidemic. Myriad barriers to retention include stigma, homophobia, structural barriers, transportation, and insurance. The purpose of this study was to evaluate patient perceptions of provider attitudes among HIV-infected persons within a state-wide public hospital system in Louisiana. A convenience sample of patients attending HIV clinics throughout the state participated in an anonymous interview. Factors associated with negative perceptions of care were evaluated in conjunction with a validated stigma measure. Factors associated with having a delayed entry into or break in care were evaluated in conjunction with perceived stigma. Between 2/1/09 and 7/31/11, 479 participants were interviewed and had sufficient data available, of whom 53.4% were male, 79.3% were African American, and 29.4% reported a break or delayed entry into HIV care of >1 year. A break in care was associated with perceiving that the doctor or health professionals do not listen carefully most or all of the time (p<0.01), having an elevated stigma score (p<0.05), and indicating that providers dislike caring for HIV-infected people (p<0.01). Women were more likely to have an elevated stigma score than men (p<0.01), as were participants over 30 (p<0.01); those with a gay/bisexual orientation (p<0.05) were less likely to have an elevated stigma score. Those with a break in care were less likely to have Medicaid (p<0.05). Providers play a key role in the retention of HIV-infected persons in care and are critical to improving outcomes and slowing the epidemic. Development of novel approaches to reduce stigma are imperative in improving retention. PMID:23651107

Correlation of myocardial p-(123)I-iodophenylpentadecanoic acid retention with (18)F-FDG accumulation during experimental low-flow ischemia.

PubMed

Shi, Cindy Q; Young, Lawrence H; Daher, Edouard; DiBella, Edward V R; Liu, Yi-Hwa; Heller, Eliot N; Zoghbi, Sami; Wackers, Frans J Th; Soufer, Robert; Sinusas, Albert J

2002-03-01

Myocardial ischemia is associated with reduced free fatty acid (FFA) beta-oxidation and increased glucose utilization. This study evaluated the potential of dynamic SPECT imaging of a FFA analog, p-(123)I-iodophenylpentadecanoic acid (IPPA), for detection of ischemia and compares retention of IPPA with (18)F-FDG accumulation. In a canine model of regional low-flow ischemia (n = 9), serial IPPA SPECT images (2 min per image) were acquired over 52--90 min. In a subset of dogs (n = 6), (18)F-FDG was injected after completing SPECT imaging and allowed to accumulate for 40 min before killing the animals. Flow was assessed with radiolabeled microspheres. Myocardial metabolism was evaluated independently by selective coronary arterial and venous sampling. Serial IPPA SPECT images showed an initial defect in the ischemic region (0.70% plus minus 0.03% ischemic-to-nonischemic ratio), which normalized within 48 min because of the slower IPPA clearance from the ischemic region (t(1/2) = 54.2 plus minus 3.3 min) relative to the nonischemic region (t(1/2) = 36.7 plus minus 5.6 min) (P < 0.05). Delayed myocardial IPPA and (18)F-FDG activities were correlated (r = 0.70; n = 576 segments), and both were maximally increased in segments with a moderate flow reduction (IPPA, 151% of nonischemic; (18)F-FDG, 450% of nonischemic; P < 0.05). Serial SPECT imaging showed delayed myocardial clearance of IPPA in ischemic regions with moderate flow reduction, which lead to increased late myocardial retention of IPPA. Retention of IPPA correlated with (18)F-FDG accumulation, supporting the potential of IPPA as a noninvasive marker of ischemic myocardium.

Evidence against decay in verbal working memory.

PubMed

Oberauer, Klaus; Lewandowsky, Stephan

2013-05-01

The article tests the assumption that forgetting in working memory for verbal materials is caused by time-based decay, using the complex-span paradigm. Participants encoded 6 letters for serial recall; each letter was preceded and followed by a processing period comprising 4 trials of difficult visual search. Processing duration, during which memory could decay, was manipulated via search set size. This manipulation increased retention interval by up to 100% without having any effect on recall accuracy. This result held with and without articulatory suppression. Two experiments using a dual-task paradigm showed that the visual search process required central attention. Thus, even when memory maintenance by central attention and by articulatory rehearsal was prevented, a large delay had no effect on memory performance, contrary to the decay notion. Most previous experiments that manipulated the retention interval and the opportunity for maintenance processes in complex span have confounded these variables with time pressure during processing periods. Three further experiments identified time pressure as the variable that affected recall. We conclude that time-based decay does not contribute to the capacity limit of verbal working memory. PsycINFO Database Record (c) 2013 APA, all rights reserved.

The loss of short-term visual representations over time: decay or temporal distinctiveness?

PubMed

Mercer, Tom

2014-12-01

There has been much recent interest in the loss of visual short-term memories over the passage of time. According to decay theory, visual representations are gradually forgotten as time passes, reflecting a slow and steady distortion of the memory trace. However, this is controversial and decay effects can be explained in other ways. The present experiment aimed to reexamine the maintenance and loss of visual information over the short term. Decay and temporal distinctiveness models were tested using a delayed discrimination task, in which participants compared complex and novel objects over unfilled retention intervals of variable length. Experiment 1 found no significant change in the accuracy of visual memory from 2 to 6 s, but the gap separating trials reliably influenced task performance. Experiment 2 found evidence for information loss at a 10-s retention interval, but temporally separating trials restored the fidelity of visual memory, possibly because temporally isolated representations are distinct from older memory traces. In conclusion, visual representations lose accuracy at some point after 6 s, but only within temporally crowded contexts. These findings highlight the importance of temporal distinctiveness within visual short-term memory. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Retention of Emergency Care Knowledge.

ERIC Educational Resources Information Center

Burckes, Mardie E.; Shao, Kung Ping Pam

1984-01-01

Data on the emergency care knowledge of college students were measured by a pretest, posttest, and retention test. A high relationship was found between students' posttest scores and retention test scores. Findings are discussed. (Author/DF)

Influence of PBL with Open-Book Tests on Knowledge Retention Measured with Progress Tests

ERIC Educational Resources Information Center

Heijne-Penninga, M.; Kuks, J. B. M.; Hofman, W. H. A.; Muijtjens, A. M. M.; Cohen-Schotanus, J.

2013-01-01

The influence of problem-based learning (PBL) and open-book tests on long-term knowledge retention is unclear and subject of discussion. Hypotheses were that PBL as well as open-book tests positively affect long-term knowledge retention. Four progress test results of fifth and sixth-year medical students (n = 1,648) of three medical schools were…

Facilitators and barriers for retention in HIV care between testing and treatment in Asia-A study in Bangladesh, Indonesia, Lao, Nepal, Pakistan, Philippines and Vietnam.

PubMed

Koirala, Sushil; Deuba, Keshab; Nampaisan, Oranuch; Marrone, Gaetano; Ekström, Anna Mia

2017-01-01

The need for efficient retention in HIV care is more evident than ever because of the expansion of earlier ART initiation and the shift towards 'Test and Treat'. This study assesses factors affecting participation in the HIV care cascade among people living with HIV (PLHIV) in the Asia-Pacific Region. A total of 7843 PLHIV aged 18-50 years were recruited using targeted and venue-based sampling between October 1, 2012, and May 31, 2013, across 59 sites in 7 countries (Bangladesh, Indonesia, Lao People's Democratic Republic (Lao PDR), Nepal, Pakistan, Philippines and Vietnam). Statistically significant associations between demographic and health system determinants, and various steps in the HIV care cascade were computed using a generalized structural equation model. A high proportion of PLHIV (40-51%) presented late for HIV care and delayed linkage to care in all seven countries. However, once PLHIV enrolled in care, retention in the various steps of the care cascade including adherence to antiretroviral treatment (ART) was satisfactory. The proportion still engaged in HIV care at 36 months post HIV diagnosis, varied from 78% in Nepal to >90% in Lao PDR. Similarly, the proportion of ART initiation who also were adherent to ART ranged from 91% in Bangladesh to >95% in Philippines/ Vietnam and from 70% in Lao PDR to 89% in the Philippines respectively. The following factors enhanced the likelihood of ART initiation and high adherence to HIV care and ART: good client-provider communication, high HIV treatment literacy, a referral from a health worker and TB/HIV co-infection. The following barriers were identified: young age, sex work, imprisonment, transgender identity, illiteracy, rural residence, alcohol/ injecting drug use, perceived poor health status, lack of health insurance, fear of confidentiality breach, self-referral for HIV testing, and public hospital as the place of HIV diagnosis. HIV programme planners should ensure easy access to HIV testing and earlier linkage to HIV care among PLHIV. In addition, multiple socio-economic and health systems barriers need to be addressed along the HIV care cascade to reach the UNAIDS 90-90-90 target in the Asia-Pacific region.

49 CFR 219.901 - Retention of alcohol testing records.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Retention of alcohol testing records. 219.901... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CONTROL OF ALCOHOL AND DRUG USE Recordkeeping Requirements § 219.901 Retention of alcohol testing records. (a) General requirement. In addition to the records required to be...

49 CFR 219.903 - Retention of drug testing records.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Retention of drug testing records. 219.903 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CONTROL OF ALCOHOL AND DRUG USE Recordkeeping Requirements § 219.903 Retention of drug testing records. (a) General requirement. In addition to the records required to be kept...

49 CFR 219.903 - Retention of drug testing records.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Retention of drug testing records. 219.903 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CONTROL OF ALCOHOL AND DRUG USE Recordkeeping Requirements § 219.903 Retention of drug testing records. (a) General requirement. In addition to the records required to be kept...

49 CFR 219.903 - Retention of drug testing records.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Retention of drug testing records. 219.903 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CONTROL OF ALCOHOL AND DRUG USE Recordkeeping Requirements § 219.903 Retention of drug testing records. (a) General requirement. In addition to the records required to be kept...

49 CFR 219.903 - Retention of drug testing records.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Retention of drug testing records. 219.903 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CONTROL OF ALCOHOL AND DRUG USE Recordkeeping Requirements § 219.903 Retention of drug testing records. (a) General requirement. In addition to the records required to be kept...

49 CFR 219.903 - Retention of drug testing records.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Retention of drug testing records. 219.903 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CONTROL OF ALCOHOL AND DRUG USE Recordkeeping Requirements § 219.903 Retention of drug testing records. (a) General requirement. In addition to the records required to be kept...

16 CFR Figure 8 to Part 1203 - Apparatus for Test of Retention System Strength

Code of Federal Regulations, 2011 CFR

2011-01-01

... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Apparatus for Test of Retention System Strength 8 Figure 8 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT...—Apparatus for Test of Retention System Strength ER10MR98.008 ...

16 CFR Figure 8 to Part 1203 - Apparatus for Test of Retention System Strength

Code of Federal Regulations, 2010 CFR

2010-01-01

... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Apparatus for Test of Retention System Strength 8 Figure 8 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT...—Apparatus for Test of Retention System Strength ER10MR98.008 ...

Delayed-onset dementia after stroke or transient ischemic attack.

PubMed

Mok, Vincent C T; Lam, Bonnie Y K; Wang, Zhaolu; Liu, Wenyan; Au, Lisa; Leung, Eric Y L; Chen, Sirong; Yang, Jie; Chu, Winnie C W; Lau, Alexander Y L; Chan, Anne Y Y; Shi, Lin; Fan, Florence; Ma, Sze H; Ip, Vincent; Soo, Yannie O Y; Leung, Thomas W H; Kwok, Timothy C Y; Ho, Chi L; Wong, Lawrence K S; Wong, Adrian

2016-11-01

Patients surviving stroke without immediate dementia are at high risk of delayed-onset dementia. Mechanisms underlying delayed-onset dementia are complex and may involve vascular and/or neurodegenerative diseases. Dementia-free patients with stroke and/or transient ischemic attack (TIA; n = 919) were studied for 3 years prospectively, excluding those who developed dementia 3 to 6 months after stroke and/or TIA. Forty subjects (4.4%) developed dementia during the study period. Imaging markers of severe small vessel disease (SVD), namely presence of ≥3 lacunes and confluent white matter changes; history of hypertension and diabetes mellitus independently predicted delayed-onset dementia after adjustment for age, gender, and education. Only 6 of 31 (19.4%) subjects with delayed cognitive decline harbored Alzheimer's disease-like Pittsburg compound B (PiB) retention. Most PiB cases (16/25, 64%) had evidence of severe SVD. Severe SVD contributes importantly to delayed-onset dementia after stroke and/or TIA. Future clinical trials aiming to prevent delayed-onset dementia after stroke and/or TIA should target this high-risk group. Copyright © 2016 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

Early onset marijuana use is associated with learning inefficiencies.

PubMed

Schuster, Randi Melissa; Hoeppner, Susanne S; Evins, A Eden; Gilman, Jodi M

2016-05-01

Verbal memory difficulties are the most widely reported and persistent cognitive deficit associated with early onset marijuana use. Yet, it is not known what memory stages are most impaired in those with early marijuana use. Forty-eight young adults, aged 18-25, who used marijuana at least once per week and 48 matched nonusing controls (CON) completed the California Verbal Learning Test, Second Edition (CVLT-II). Marijuana users were stratified by age of initial use: early onset users (EMJ), who started using marijuana at or before age 16 (n = 27), and late onset marijuana user group (LMJ), who started using marijuana after age 16 (n = 21). Outcome variables included trial immediate recall, total learning, clustering strategies (semantic clustering, serial clustering, ratio of semantic to serial clustering, and total number of strategies used), delayed recall, and percent retention. Learning improved with repetition, with no group effect on the learning slope. EMJ learned fewer words overall than LMJ or CON. There was no difference between LMJ and CON in total number of words learned. Reduced overall learning mediated the effect on reduced delayed recall among EMJ, but not CON or LMJ. Learning improved with greater use of semantic versus serial encoding, but this did not vary between groups. EMJ was not related to delayed recall after adjusting for encoding. Young adults reporting early onset marijuana use had learning weaknesses, which accounted for the association between early onset marijuana use and delayed recall. No amnestic effect of marijuana use was observed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Early Onset Marijuana Use Is Associated with Learning Inefficiencies

PubMed Central

Schuster, Randi Melissa; Hoeppner, Susanne S.; Evins, A. Eden; Gilman, Jodi M.

2016-01-01

Objective Verbal memory difficulties are the most widely reported and persistent cognitive deficit associated with early-onset marijuana use. Yet, it is not known what memory stages are most impaired in those with early marijuana use. Method Forty-eight young adults, aged 18–25, who used marijuana at least once per week and 48 matched non-using controls (CON) completed the California Verbal Learning Test, Second Edition (CVLT-II). Marijuana users were stratified by age of initial use: ‘early onset’ users (EMJ), who started using marijuana at or before age 16 (n = 27), and ‘late onset’ marijuana user group (LMJ), who started using marijuana after age 16 (n = 21). Outcome variables included trial immediate recall, total learning, clustering strategies (semantic clustering, serial clustering, ratio of semantic to serial clustering, and total number of strategies used), delayed recall, and percent retention. Results Learning improved with repetition, with no group effect on the learning slope. EMJ learned fewer words overall than LMJ or CON. There was no difference between LMJ and CON in total number of words learned. Reduced overall learning mediated the effect on reduced delayed recall among EMJ, but not CON or LMJ. Learning improved with greater use of semantic versus serial encoding, but this did not vary between groups. EMJ was not related to delayed recall after adjusting for encoding. Conclusions Young adults reporting early onset marijuana use had learning weaknesses, which accounted for the association between early onset marijuana use and delayed recall. No amnestic effect of marijuana use was observed. PMID:26986749

Associations between basal cortisol levels and memory retrieval in healthy young individuals.

PubMed

Ackermann, Sandra; Hartmann, Francina; Papassotiropoulos, Andreas; de Quervain, Dominique J F; Rasch, Björn

2013-11-01

Cortisol is known to affect memory processes. On the one hand, stress-induced or pharmacologically induced elevations of cortisol levels enhance memory consolidation. On the other hand, such experimentally induced elevations of cortisol levels have been shown to impair memory retrieval. However, the effects of individual differences in basal cortisol levels on memory processes remain largely unknown. Here we tested whether individual differences in cortisol levels predict picture learning and recall in a large sample. A total of 1225 healthy young women and men viewed two different sets of emotional and neutral pictures on two consecutive days. Both sets were recalled after a short delay (10 min). On Day 2, the pictures seen on Day 1 were additionally recalled, resulting in a long-delay (20 hr) recall condition. Cortisol levels were measured three times on Days 1 and 2 via saliva samples before encoding, between encoding and recall as well as after recall testing. We show that stronger decreases in cortisol levels during retrieval testing were associated with better recall performance of pictures, regardless of emotional valence of the pictures or length of the retention interval (i.e., 10 min vs. 20 hr). In contrast, average cortisol levels during retrieval were not related to picture recall. Remarkably during encoding, individual differences in average cortisol levels as well as changes in cortisol did not predict memory recall. Our results support previous findings indicating that higher cortisol levels during retrieval testing hinders recall of episodic memories and extend this view onto interindividual changes in basal cortisol levels.

Magical thinking and memory: distinctiveness effect for tv commercials with magical content.

PubMed

Subbotsky, Eugene; Mathews, Jayne

2011-10-01

The aim of this study was to examine whether memorizing advertised products of television advertisements with magical effects (i.e., talking animals, inanimate objects which turn into humans, objects that appear from thin air or instantly turn into other objects) is easier than memorizing products of advertisements without such effects, by testing immediate and delayed retention. Adolescents and adults viewed two films containing television advertisements and were asked to recall and recognize the films' characters, events, and advertised products. Film 1 included magical effects, but Film 2 did not. On a free-recall test, no differences in the number of items recalled were noted for the two films. On the immediate recognition test, adolescents, but not adults, showed significantly better recognition for the magical than the nonmagical film. When this test was repeated two weeks later, results were reversed: adults, but not adolescents, recognized a significantly larger number of items from the magical film than the nonmagical one. These results are interpreted to accentuate the role of magical thinking in cognitive processes.

GABA[subscript A] Receptors Determine the Temporal Dynamics of Memory Retention

ERIC Educational Resources Information Center

McNally, Gavan P.; Augustyn, Katarzyna A.; Richardson, Rick

2008-01-01

Four experiments studied the role of GABA[subscript A] receptors in the temporal dynamics of memory retention. Memory for an active avoidance response was a nonmonotonic function of the retention interval. When rats were tested shortly (2 min) or some time (24 h) after training, retention was excellent, but when they were tested at intermediate…

Double dissociation of pharmacologically induced deficits in visual recognition and visual discrimination learning

PubMed Central

Turchi, Janita; Buffalari, Deanne; Mishkin, Mortimer

2008-01-01

Monkeys trained in either one-trial recognition at 8- to 10-min delays or multi-trial discrimination habits with 24-h intertrial intervals received systemic cholinergic and dopaminergic antagonists, scopolamine and haloperidol, respectively, in separate sessions. Recognition memory was impaired markedly by scopolamine but not at all by haloperidol, whereas habit formation was impaired markedly by haloperidol but only minimally by scopolamine. These differential drug effects point to differences in synaptic modification induced by the two neuromodulators that parallel the contrasting properties of the two types of learning, namely, fast acquisition but weak retention of memories versus slow acquisition but durable retention of habits. PMID:18685146

Double dissociation of pharmacologically induced deficits in visual recognition and visual discrimination learning.

PubMed

Turchi, Janita; Buffalari, Deanne; Mishkin, Mortimer

2008-08-01

Monkeys trained in either one-trial recognition at 8- to 10-min delays or multi-trial discrimination habits with 24-h intertrial intervals received systemic cholinergic and dopaminergic antagonists, scopolamine and haloperidol, respectively, in separate sessions. Recognition memory was impaired markedly by scopolamine but not at all by haloperidol, whereas habit formation was impaired markedly by haloperidol but only minimally by scopolamine. These differential drug effects point to differences in synaptic modification induced by the two neuromodulators that parallel the contrasting properties of the two types of learning, namely, fast acquisition but weak retention of memories versus slow acquisition but durable retention of habits.

Understanding the Effects of Different Study Methods on Retention of Information and Transfer of Learning

ERIC Educational Resources Information Center

Egan, Rylan G.

2012-01-01

Introduction: The following study investigates relationships between spaced practice (re-studying after a delay) and transfer of learning. Specifically, the impact on learners ability to transfer learning after participating in spaced model-building or unstructured study of narrated text. Method: Subjects were randomly assigned either to a…

Eye Movements and Overt Rehearsal in Word Recall

ERIC Educational Resources Information Center

Geiselman, Ralph E.; Bellezza, Francis S.

1977-01-01

Rates of overt rehearsal and eye movement were compared to each other, and were also compared as predictors of immediate and delayed recall. Concludes that total looking time was the best predictor of long-term retention and that recall performance following overt rehearsal was different from recall performance following silent study. (Editor/RK)

The Consequences of Delayed Enrollment in Developmental Mathematics

ERIC Educational Resources Information Center

Fike, David S.; Fike, Renea

2012-01-01

Though a large percentage of U.S. students enter higher education with mathematics deficiencies, many institutions allow these students to decide the timing of their enrollment in developmental mathematics courses. This study of 3476 first-time-in-college students entailed the review of student outcomes (Fall GPA, Fall-to-Spring retention,…

Mathematics Practice without Feedback: A Desirable Difficulty in a Classroom Setting

ERIC Educational Resources Information Center

Fyfe, Emily R.; Rittle-Johnson, Bethany

2017-01-01

Recent research highlights the potential benefits of practice without feedback on learner's strategy knowledge. However, most prior work has been conducted in one-on-one settings with short retention intervals. We compared the effects of mathematics practice with and without correct-answer feedback on immediate and 1-week delayed performance in a…

Psychophysics of remembering.

PubMed Central

White, K G; Wixted, J T

1999-01-01

We present a new model of remembering in the context of conditional discrimination. For procedures such as delayed matching to sample, the effect of the sample stimuli at the time of remembering is represented by a pair of Thurstonian (normal) distributions of effective stimulus values. The critical assumption of the model is that, based on prior experience, each effective stimulus value is associated with a ratio of reinforcers obtained for previous correct choices of the comparison stimuli. That ratio determines the choice that is made on the basis of the matching law. The standard deviations of the distributions are assumed to increase with increasing retention-interval duration, and the distance between their means is assumed to be a function of other factors that influence overall difficulty of the discrimination. It is a behavioral model in that choice is determined by its reinforcement history. The model predicts that the biasing effects of the reinforcer differential increase with decreasing discriminability and with increasing retention-interval duration. Data from several conditions using a delayed matching-to-sample procedure with pigeons support the predictions. PMID:10028693

Effect of EDTA conditioning upon the retention of fibre posts luted with resin cements.

PubMed

Rasimick, B J; Shah, R P; Musikant, B L; Deutsch, A S

2008-12-01

To determine if a final rinse with EDTA improves the short-term in-tooth retentive strength of adhesively luted fibre-reinforced composite posts. Six different commercial fibre post systems were tested. Post spaces in extracted human anterior teeth were irrigated with either 6% NaOCl or 6% NaOCl followed by 17% EDTA. Posts were luted using the manufacturer's recommended bonding agent and luting cement. Two different sizes of post were tested for each post system. After 24 h of storage, the retentive strength of the post to the tooth (14 per group, 336 total) was tested using a pull-out technique. Three-way anova and the Student-Newman-Kuels test were used to test the effects of irrigation regimen, post size and post brand on the retentive strength of the fibre post. Almost every sample failed at the interface between dentine and luting cement. Irrigation method did not have any significant effect (P > 0.14) for any group other than ParaPost Fibre White (P < 0.001). The overall retention of a post appeared to be correlated to the amount of surface texture on the post; the smooth ICEPost was the least retentive brand, the textured FibreKor and the ParaPost Fibre White posts were moderately retained, and the threaded Flexi-Post Fibre and the Flexi-Flange Fibre posts were the most retentive brands tested. For all brands, larger diameter posts were more retentive than smaller diameter posts (P < 0.008). A final rinse of EDTA did not improve the short-term retention of fibre posts except for ParaPost Fibre White.

Neural correlates of sample-coding and reward-coding in the delay activity of neurons in the entopallium and nidopallium caudolaterale of pigeons (Columba livia).

PubMed

Johnston, Melissa; Anderson, Catrona; Colombo, Michael

2017-01-15

We recorded neuronal activity from the nidopallium caudolaterale, the avian equivalent of mammalian prefrontal cortex, and the entopallium, the avian equivalent of the mammalian visual cortex, in four birds trained on a differential outcomes delayed matching-to-sample procedure in which one sample stimulus was followed by reward and the other was not. Despite similar incidence of reward-specific and reward-unspecific delay cell types across the two areas, overall entopallium delay activity occurred following both rewarded and non-rewarded stimuli, whereas nidopallium caudolaterale delay activity tended to occur following the rewarded stimulus but not the non-rewarded stimulus. These findings are consistent with the view that delay activity in entopallium represents a code of the sample stimulus whereas delay activity in nidopallium caudolaterale represents a code of the possibility of an upcoming reward. However, based on the types of delay cells encountered, cells in NCL also code the sample stimulus and cells in ENTO are influenced by reward. We conclude that both areas support the retention of information, but that the activity in each area is differentially modulated by factors such as reward and attentional mechanisms. Copyright © 2016 Elsevier B.V. All rights reserved.

Remembering 1500 pictures: the right hemisphere remembers better than the left.

PubMed

Laeng, Bruno; Øvervoll, Morten; Ole Steinsvik, Oddmar

2007-03-01

We hypothesized that the right hemisphere would be superior to the left hemisphere in remembering having seen a specific picture before, given its superiority in perceptually encoding specific aspects of visual form. A large set of pictures (N=1500) of animals, human faces, artifacts, landscapes, and art paintings were shown for 2s in central vision, or tachistoscopically (for 100ms) in each half visual field, to normal participants who were then tested 1-6 days later for their recognition. Images that were presented initially to the right hemisphere were better recognized than those presented to the left hemisphere. These results, obtained with participants with intact brains, large number of stimuli, and long retention delays, are consistent with previously described hemispheric differences in the memory of split-brain patients.

Biocompatibility of antimicrobial melimine lenses: rabbit and human studies.

PubMed

Dutta, Debarun; Ozkan, Jerome; Willcox, Mark D P

2014-05-01

Covalent immobilization of antimicrobial peptide melimine onto contact lenses can produce broad-spectrum antimicrobial lenses. The purpose of this study was to investigate the performance of melimine-coated contact lenses in an animal model and human clinical trial. Melimine was covalently attached onto the surface of contact lenses via EDC (1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride) coupling. A rabbit model of daily contralateral wear of lenses for 22 days was conducted to assess the lens safety. A prospective, randomized, double-masked, one-day human clinical trial was used to evaluate subjective responses and ocular physiology during contralateral wear of melimine-coated (test) and uncoated (control) lenses. Delayed reactions were monitored during follow-up visits after 1 and 4 weeks. Ex vivo retention of antimicrobial activity of worn lenses was assessed by reduction in numbers of viable Pseudomonas aeruginosa and Staphylococcus aureus. Melimine-coated lenses produced no ocular signs or symptoms that would indicate cytotoxicity during the lens wear of rabbits. No histological changes were found in rabbit corneas. During the human trial, no differences were observed in wettability, surface deposition, lens-fitting centration, movement, tightness, and corneal coverage between test and control lenses (p > 0.05). There were no significant differences in bulbar, limbal, or palpebral redness or conjunctival staining (p > 0.05). Mean corneal (extent, depth, and type) staining was higher for test lenses compared with that for control lenses (p < 0.05). There was no significant difference in subjective responses for lens comfort, dryness, and awareness (p > 0.05). No delayed reactions were associated with the test lenses. Worn test lenses retained more than 1.5 log inhibition against both bacterial types. Melimine-coated contact lenses were worn safely by humans. However, they were associated with higher corneal staining. The melimine-coated lenses retained high antibacterial activity after wear.

Preliminary data on the effect of culture on the assessment of Alzheimer's disease-related verbal memory impairment with the International Shopping List Test.

PubMed

Lim, Yen Ying; Pietrzak, Robert H; Snyder, Peter J; Darby, David; Maruff, Paul

2012-03-01

The International Shopping List Test (ISLT) is a measure of verbal learning and memory, developed specifically for use in people from different cultural and linguistic backgrounds. In this report, we describe two studies that examined the ISLT's ability to detect memory impairment and memory decline in patients with mild Alzheimer's disease (AD) from a range of cultural and linguistic backgrounds. In Study 1, the performance of Australian-English-speaking adults with mild AD was compared with that of native Australian-English- and Korean-speaking patients with mild AD. Compared with controls, patients with AD from both language groups showed large but equivalent impairments in total recall, delayed recall, rate of learning, and primacy and retention-weighted recall (RWR) measures on the ISLT. In Study 2, the rate of deterioration in verbal memory over 1 year was examined in groups of native Canadian-English, French, and Korean speakers with mild AD using the total recall, delayed recall, and RWR measures. Rates of change on all three measures were equivalent across the language groups, although the magnitude of deterioration was most pronounced for the total recall and RWR measures. Taken together, these results suggest that the ISLT is valid and reliable for the assessment of verbal learning and memory impairment and decline in patients with mild AD from diverse language groups.

Atrial stretch delays gastric emptying of liquids in awake rats.

PubMed

Palheta, R C; Silva, M T B; Barbosa, H L G; Pinheiro, A D N; Cardoso, K V V; Graça, J R V; Magalhães, P J C; Oliveira, R B; Santos, A A

2013-03-21

We previously reported that mechanical atrial stretch (AS) by balloon distention increased gastric tonus in anesthetized rats. The present study evaluated the effect of AS on the gastric emptying of a liquid test meal in awake rats and its underlying neural mechanisms. Anesthetized male rats received a balloon catheter into the right atrium and a gastrostomy cannula. The next day, mean arterial pressure (MAP), heart rate (HR), central venous pressure (CVP), and cardiac output (CO) were continuously monitored. After the first 20min of monitoring (basal interval), the balloon was either distended or not (control) with 30, 50, or 70μl saline for 5min. Fifteen minutes later, the rats received the test meal (glucose solution with phenol red), and fractional gastric dye retention was determined 10, 20, or 30min later. Heart rate and CVP values were transiently increased by 50 or 70μl AS but not 30μl AS, whereas gastric emptying was slower after 30, 50, or 70μl AS than after sham distention. Subdiaphragmatic vagotomy or splanchnicotomy+celiac ganglionectomy and capsaicin, ondansetron, hexamethonium, L-NAME, and glibenclamide treatment prevented the AS-induced delay in gastric emptying, whereas atropine and guanethidine treatment failed to prevent it. Atrial stretch inhibited the gastric emptying of liquid via non-adrenergic and non-cholinergic pathways that activate nitric oxide-K(+)ATP channels. Copyright © 2013 Elsevier Inc. All rights reserved.

Increased Alpha-Band Power during the Retention of Shapes and Shape-Location Associations in Visual Short-Term Memory

PubMed Central

Johnson, Jeffrey S.; Sutterer, David W.; Acheson, Daniel J.; Lewis-Peacock, Jarrod A.; Postle, Bradley R.

2011-01-01

Studies exploring the role of neural oscillations in cognition have revealed sustained increases in alpha-band (~8–14 Hz) power during the delay period of delayed-recognition short-term memory tasks. These increases have been proposed to reflect the inhibition, for example, of cortical areas representing task-irrelevant information, or of potentially interfering representations from previous trials. Another possibility, however, is that elevated delay-period alpha-band power (DPABP) reflects the selection and maintenance of information, rather than, or in addition to, the inhibition of task-irrelevant information. In the present study, we explored these possibilities using a delayed-recognition paradigm in which the presence and task relevance of shape information was systematically manipulated across trial blocks and electroencephalographic was used to measure alpha-band power. In the first trial block, participants remembered locations marked by identical black circles. The second block featured the same instructions, but locations were marked by unique shapes. The third block featured the same stimulus presentation as the second, but with pretrial instructions indicating, on a trial-by-trial basis, whether memory for shape or location was required, the other dimension being irrelevant. In the final block, participants remembered the unique pairing of shape and location for each stimulus. Results revealed minimal DPABP in each of the location-memory conditions, whether locations were marked with identical circles or with unique task-irrelevant shapes. In contrast, alpha-band power increases were observed in both the shape-memory condition, in which location was task irrelevant, and in the critical final condition, in which both shape and location were task relevant. These results provide support for the proposal that alpha-band oscillations reflect the retention of shape information and/or shape–location associations in short-term memory. PMID:21713012

16 CFR 1203.13 - Test schedule.

Code of Federal Regulations, 2010 CFR

2010-01-01

... environments, respectively) shall be tested in accordance with the dynamic retention system strength test at... Peripheral vision § 1203.15 Positional stability § 1203.16 Retention system strength § 1203.17 Impact tests...

Learning, retention, and generalization of haptic categories

NASA Astrophysics Data System (ADS)

Do, Phuong T.

This dissertation explored how haptic concepts are learned, retained, and generalized to the same or different modality. Participants learned to classify objects into three categories either visually or haptically via different training procedures, followed by an immediate or delayed transfer test. Experiment I involved visual versus haptic learning and transfer. Intermodal matching between vision and haptics was investigated in Experiment II. Experiments III and IV examined intersensory conflict in within- and between-category bimodal situations to determine the degree of perceptual dominance between sight and touch. Experiment V explored the intramodal relationship between similarity and categorization in a psychological space, as revealed by MDS analysis of similarity judgments. Major findings were: (1) visual examination resulted in relatively higher performance accuracy than haptic learning; (2) systematic training produced better category learning of haptic concepts across all modality conditions; (3) the category prototypes were rated newer than any transfer stimulus followed learning both immediately and after a week delay; and, (4) although they converged at the apex of two transformational trajectories, the category prototypes became more central to their respective categories and increasingly structured as a function of learning. Implications for theories of multimodal similarity and categorization behavior are discussed in terms of discrimination learning, sensory integration, and dominance relation.

Semantic Information Activated during Retrieval Contributes to Later Retention: Support for the Mediator Effectiveness Hypothesis of the Testing Effect

ERIC Educational Resources Information Center

Carpenter, Shana K.

2011-01-01

Previous research has proposed that tests enhance retention more than do restudy opportunities because they promote the effectiveness of mediating information--that is, a word or concept that links a cue to a target (Pyc & Rawson, 2010). Although testing has been shown to promote retention of mediating information that participants were asked…

Fastener load tests and retention systems tests for cryogenic wind-tunnel models

NASA Technical Reports Server (NTRS)

Wallace, J. W.

1984-01-01

A-286 stainless steel screws were tested to determine the tensile load capability and failure mode of various screw sizes and types at both cryogenic and room temperature. Additionally, five fastener retention systems were tested by using A-286 screws with specimens made from the primary metallic alloys that are currently used for cryogenic models. The locking system effectiveness was examined by simple no-load cycling to cryogenic temperatures (-275 F) as well as by dynamic and static loading at cryogenic temperatures. In general, most systems were found to be effective retention devices. There are some differences between the various devices with respect to ease of application, cleanup, and reuse. Results of tests at -275 F imply that the cold temperatures act to improve screw retention. The improved retention is probably the result of differential thermal contraction and/or increased friction (thread-binding effects). The data provided are useful in selecting screw sizes, types, and locking devices for model systems to be tested in cryogenic wind tunnels.

Influence of PBL with open-book tests on knowledge retention measured with progress tests.

PubMed

Heijne-Penninga, M; Kuks, J B M; Hofman, W H A; Muijtjens, A M M; Cohen-Schotanus, J

2013-08-01

The influence of problem-based learning (PBL) and open-book tests on long-term knowledge retention is unclear and subject of discussion. Hypotheses were that PBL as well as open-book tests positively affect long-term knowledge retention. Four progress test results of fifth and sixth-year medical students (n = 1,648) of three medical schools were analyzed. Two schools had PBL driven curricula, and the third one had a traditional curriculum (TC). One of the PBL schools (PBLob) used a combination of open-book (assessing backup knowledge) and closed-book tests (assessing core knowledge); the other two schools (TC and PBLcb) only used closed-book tests. The items of the progress tests were divided into core and backup knowledge. T tests (with Bonferroni correction) were used to analyze differences between curricula. PBL students performed significantly better than TC students on core knowledge (average effect size (av ES) = 0.37-0.74) and PBL students tested with open-book tests scored somewhat higher than PBL students tested without such tests (av ES = 0.23-0.30). Concerning backup knowledge, no differences were found between the scores of the three curricula. Students of the two PBL curricula showed a substantially better long-term knowledge retention than TC students. PBLob students performed somewhat better on core knowledge than PBLcb students. These outcomes suggest that a problem-based instructional approach in particular can stimulate long-term knowledge retention. Distinguishing knowledge into core and backup knowledge and using open-book tests alongside closed-book tests could enhance long-term core knowledge retention.

Using Student Modeling to Estimate Student Knowledge Retention

ERIC Educational Resources Information Center

Wang, Yutao; Beck, Joseph E.

2012-01-01

The goal of predicting student behavior on the immediate next action has been investigated by researchers for many years. However, a fair question is whether this research question is worth all of the attention it has received. This paper investigates predicting student performance after a delay of 5 to 10 days, to determine whether, and when, the…

A Model for Stochastic Drift in Memory Strength to Account for Judgments of Learning

ERIC Educational Resources Information Center

Sikstrom, Sverker; Jonsson, Fredrik

2005-01-01

Previous research has shown that judgments of learning (JOLs) made immediately after encoding have a low correlation with actual cued-recall performance, whereas the correlation is high for delayed judgments. In this article, the authors propose a formal theory describing the stochastic drift of memory strength over the retention interval to…

The Effects of Alphabetic Organization on the Acquisition and Delayed Retention of Semantically Similar Words

ERIC Educational Resources Information Center

Lauer, Patricia A.; And Others

1976-01-01

This experiment attempts to maximize orthographic while reducing semantic bases for processing by using lists of words from a single category (girl's first names), presenting the first letter as a cue for each word during both study and recall trials, and blocking together all words with the same first letter. (Author)

Planning and Realization of Complex Intentions in Traumatic Brain Injury and Normal Aging

ERIC Educational Resources Information Center

Kliegel, Matthias; Eschen, Anne; Thone-Otto, Angelika I. T.

2004-01-01

The realization of delayed intentions (i.e., prospective memory) is a highly complex process composed of four phases: intention formation, retention, re-instantiation, and execution. The aim of this study was to investigate if executive functioning impairments are related to problems in the formation, re-instantiation, and execution of a delayed…

Faculty's Role in the Retention of Nontraditional Undergraduate Students

ERIC Educational Resources Information Center

Dutcher, Gail Lynam

2016-01-01

Nontraditional students are students who are at least 25 years old and attend school on a part-time basis. They also have one or more of the following characteristics: delayed enrollment in higher education, full-time work, financially independent, have dependents, are single parents, and do not have a high school diploma (Choy, 2002). Retention…

How much basic science content do second-year medical students remember from their first year?

PubMed

Schneid, Stephen D; Pashler, Hal; Armour, Chris

2018-01-23

While most medical students generally perform well on examinations and pass their courses during the first year, we do not know how much basic science content they retain at the start of their second year and how that relates to minimal competency set by the faculty. In the fall of 2014, before starting their second-year courses, 27 medical students volunteered to participate in a study of long-term retention of the basic sciences by taking a "retention exam" after a delay of 5-11 months. The overall mean performance when the students initially answered the 60 multiple choice questions (MCQs) was 82.8% [standard deviation (SD) = 7.4%], which fell to 50.1% (SD = 12.1%) on the retention exam. This gave a mean retention of 60.4% (SD = 12.8%) with the retention for individual students ranging from 37 to 81%. The majority of students (23/27; 85%) fell below the minimal level of competency to start their second year. Medical educators should be more aware of the significant amount of forgetting that occurs during training and make better use of instructional strategies that promote long-term learning such as retrieval practice, interleaving, and spacing.

What drives sleep-dependent memory consolidation: greater gain or less loss?

PubMed

Fenn, Kimberly M; Hambrick, David Z

2013-06-01

When memory is tested after a delay, performance is typically better if the retention interval includes sleep. However, it is unclear what accounts for this well-established effect. It is possible that sleep enhances the retrieval of information, but it is also possible that sleep protects against memory loss that normally occurs during waking activity. We developed a new research approach to investigate these possibilities. Participants learned a list of paired-associate items and were tested on the items after a 12-h interval that included waking or sleep. We analyzed the number of items gained versus the number of items lost across time. The sleep condition showed more items gained and fewer items lost than did the wake condition. Furthermore, the difference between the conditions (favoring sleep) in lost items was greater than the difference in gain, suggesting that loss prevention may primarily account for the effect of sleep on declarative memory consolidation. This finding may serve as an empirical constraint on theories of memory consolidation.

Learning new vocabulary in German: the effects of inferring word meanings, type of feedback, and time of test.

PubMed

Carpenter, Shana K; Sachs, Riebana E; Martin, Beth; Schmidt, Kristian; Looft, Ruxandra

2012-02-01

In the present study, introductory-level German students read a simplified story and learned the meanings of new German words by reading English translations in marginal glosses versus trying to infer (i.e., guess) their translations. Students who inferred translations were given feedback in English or in German, or no feedback at all. Although immediate retention of new vocabulary was better for students who used marginal glosses, students who inferred word meanings and then received English feedback forgot fewer translations over time. Plausible but inaccurate inferences (i.e., those that made sense in the context) were more likely to be corrected by students who received English feedback as compared with German feedback, providing support for the beneficial effects of mediating information. Implausible inaccurate inferences, however, were more likely to be corrected on the delayed vocabulary test by students who received German feedback as compared with English feedback, possibly because of the additional contextual support provided by German feedback.

Vocational Training with HIV Prevention for Ugandan Youth

PubMed Central

Rotheram-Borus, Mary Jane; Lightfoot, Marguerita; Kasirye, Rogers; Desmond, Katherine

2013-01-01

In a pilot study, young people in slums in Kampala, Uganda received an HIV prevention program (Street Smart) and were randomized to receive vocational training immediately (Immediate) or four months later (Delayed). Youth were monitored at recruitment, 4 months (85% retention), and 24 months (74% retention). Employment increased dramatically: Only 48% had ever been employed at recruitment, 86% were employed from months 21 to 24 post recruitment. Over two years, decreases were recorded in the number of sexual partners, mental health symptoms, delinquent acts, and drug use; condom use increased. Providing employment in low income countries, in conjunction with HIV prevention, may provide sustained support to young people to prevent HIV acquisition. PMID:21800180

40 CFR Appendix A to Part 282 - State Requirements Incorporated by Reference in Part 282 of the Code of Federal Regulations

Code of Federal Regulations, 2011 CFR

2011-07-01

... test of self-insurance Section 11-281-97Guarantee Section 11-281-98Insurance and risk retention group... 1111Financial Test of Self-Insurance Section 1113Guarantee Section 1115Insurance and Risk Retention Group... mechanisms 280.95Financial test of self-insurance 280.96Guarantee 280.97Insurance and risk retention group...

40 CFR Appendix A to Part 282 - State Requirements Incorporated by Reference in Part 282 of the Code of Federal Regulations

Code of Federal Regulations, 2013 CFR

2013-07-01

... test of self-insurance Section 11-281-97Guarantee Section 11-281-98Insurance and risk retention group... 1111Financial Test of Self-Insurance Section 1113Guarantee Section 1115Insurance and Risk Retention Group... mechanisms 280.95Financial test of self-insurance 280.96Guarantee 280.97Insurance and risk retention group...

40 CFR Appendix A to Part 282 - State Requirements Incorporated by Reference in Part 282 of the Code of Federal Regulations

Code of Federal Regulations, 2012 CFR

2012-07-01

... test of self-insurance Section 11-281-97Guarantee Section 11-281-98Insurance and risk retention group... 1111Financial Test of Self-Insurance Section 1113Guarantee Section 1115Insurance and Risk Retention Group... mechanisms 280.95Financial test of self-insurance 280.96Guarantee 280.97Insurance and risk retention group...

40 CFR Appendix A to Part 282 - State Requirements Incorporated by Reference in Part 282 of the Code of Federal Regulations

Code of Federal Regulations, 2010 CFR

2010-07-01

... test of self-insurance Section 11-281-97Guarantee Section 11-281-98Insurance and risk retention group... 1111Financial Test of Self-Insurance Section 1113Guarantee Section 1115Insurance and Risk Retention Group... mechanisms 280.95Financial test of self-insurance 280.96Guarantee 280.97Insurance and risk retention group...

40 CFR Appendix A to Part 282 - State Requirements Incorporated by Reference in Part 282 of the Code of Federal Regulations

Code of Federal Regulations, 2014 CFR

2014-07-01

... test of self-insurance Section 11-281-97Guarantee Section 11-281-98Insurance and risk retention group... 1111Financial Test of Self-Insurance Section 1113Guarantee Section 1115Insurance and Risk Retention Group... mechanisms 280.95Financial test of self-insurance 280.96Guarantee 280.97Insurance and risk retention group...

Influence of yoga on postoperative outcomes and wound healing in early operable breast cancer patients undergoing surgery.

PubMed

Rao, Raghavendra M; Nagendra, H R; Raghuram, Nagarathna; Vinay, C; Chandrashekara, S; Gopinath, K S; Srinath, B S

2008-01-01

Pre- and postoperative distress in breast cancer patients can cause complications and delay recovery from surgery. The aim of our study was to evaluate the effects of yoga intervention on postoperative outcomes and wound healing in early operable breast cancer patients undergoing surgery. Ninety-eight recently diagnosed stage II and III breast cancer patients were recruited in a randomized controlled trial comparing the effects of a yoga program with supportive therapy and exercise rehabilitation on postoperative outcomes and wound healing following surgery. Subjects were assessed at the baseline prior to surgery and four weeks later. Sociodemographic, clinical and investigative notes were ascertained in the beginning of the study. Blood samples were collected for estimation of plasma cytokines-soluble Interleukin (IL)-2 receptor (IL-2R), tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma. Postoperative outcomes such as the duration of hospital stay and drain retention, time of suture removal and postoperative complications were ascertained. We used independent samples t test and nonparametric Mann Whitney U tests to compare groups for postoperative outcomes and plasma cytokines. Regression analysis was done to determine predictors for postoperative outcomes. Sixty-nine patients contributed data to the current analysis (yoga: n = 33, control: n = 36). The results suggest a significant decrease in the duration of hospital stay (P = 0.003), days of drain retention (P = 0.001) and days for suture removal (P = 0.03) in the yoga group as compared to the controls. There was also a significant decrease in plasma TNF alpha levels following surgery in the yoga group (P < 0.001), as compared to the controls. Regression analysis on postoperative outcomes showed that the yoga intervention affected the duration of drain retention and hospital stay as well as TNF alpha levels. The results suggest possible benefits of yoga in reducing postoperative complications in breast cancer patients.

Facilitation of learning and modulation of frontal cortex acetylcholine by ventral pallidal injection of heparin glucosaminoglycan.

PubMed

De Souza Silva, M A; Jezek, K; Weth, K; Müller, H W; Huston, J P; Brandao, M L; Hasenöhrl, R U

2002-01-01

We examined the effects of heparin on learning and frontal cortex acetylcholine parameters following injection of the glucosaminoglycan into the ventral pallidum. In Experiment 1, possible mnemoactive effects of intrapallidal heparin injection were assessed. Rats with chronically implanted cannulae were administered heparin (0.1, 1.0, 10 ng) or vehicle (0.5 microl) and were tested on a one-trial step-through avoidance task. Two retention tests were carried out in each animal, one at 1.5 h after training to measure short-term memory and another at 24 h to measure long-term memory. Post-trial intrapallidal injection of 1.0 ng heparin improved both short- and long-term retention of the task, whereas the lower and the higher dose of the glucosaminoglycan had no effect. When the effective dose of heparin was injected 5 h, rather than immediately after training, it no longer facilitated long-term retention of the conditioned avoidance response. In Experiment 2, the effects of ventral pallidal heparin injection on frontal cortex acetylcholine and choline concentrations were investigated with in vivo microdialysis in anaesthetized rats. Heparin, administered in the dose of 1.0 ng, which was effective in facilitating avoidance performance, produced a delayed increase in cortical acetylcholine levels ipsi- and contralaterally to the side of intrabasalis injection, resembling the known neurochemical effects obtained for another glycosaminoglycan, chondroitin sulfate, which recently was shown to facilitate inhibitory avoidance learning and to increase frontal cortex acetylcholine. The present findings indicate that heparin, like other extracellular matrix proteoglycans, can exert beneficial effects on memory and strengthen the presumptive relationship between such promnestic effects of proteoglycans and basal forebrain cholinergic mechanisms. The data are discussed with respect to the presumed roles of matrix molecules in extrasynaptic volume transmission and in the 'cross-talk' between synapses.

[Experimental study on the retentive force of cobalt-chromium alloy, pure titanium and vitallium cast clasps in the simulated 3-year clinical use].

PubMed

Yan, Hai-xin; Zhao, Yan-bo; Qin, Li-mei; Zhu, Hai-ting; Wu, Lin

2015-12-01

To investigate the changes of retentive force of cobalt-chromium alloy, pure titanium and vitallium cast clasps in the simulated 3-year clinical use. Fifteen metal abutment crowns made of No.QT800-2 nodular cast iron were used in the test. Five clasps from each of the following alloys: cobalt-chromium alloy, pure titanium and vitallium were fabricated. The undercut depth was 0.25 mm. A masticatory simulator was used to cycle the clasp on and off the metal abutment crown 5000 times, simulating 3-year clinical use. Retentive force was measured 11 times during this process. SPSS13.0 software package was used to analyze the results. Casting defects were observed using X-ray non destructive testing (X-ray NDT) before cyclic test. Surface characteristics were qualitatively evaluated using scanning electron microscope (SEM) before and after cyclic test. The results indicated that there were significant differences (P=0.000) in the retentive force of the 3 groups before and after the cyclic test. The highest retentive force was recorded in the vitallium clasps, and the lowest retentive force was measured in the pure titanium clasps. The results of X-ray NDT depicted the typical casting defect seen at the end of the connector. SEM examination revealed that no evidence of pores and cracks in the inner surfaces of the 3 groups was found before cyclic test. Wear was evident in the inner surfaces of the 3 groups but none of the clasps exhibited any evidence of cracks after cyclic test through SEM examination. In this in vitro test, vitallium clasps show the best retentive force in the 3 groups before and after 5000 cycles at 0.25 mm undercut depth. Cobalt-chromium alloy and vitallium clasps can maintain ideal retentive force at 0.25mm undercut depth in the long-term use. Wear may be one of the reasons for the loss of retentive force of clasps in the cyclic test.

Effect of differing PowerPoint slide design on multiple-choice test scores for assessment of knowledge and retention in a theriogenology course.

PubMed

Root Kustritz, Margaret V

2014-01-01

Third-year veterinary students in a required theriogenology diagnostics course were allowed to self-select attendance at a lecture in either the evening or the next morning. One group was presented with PowerPoint slides in a traditional format (T group), and the other group was presented with PowerPoint slides in the assertion-evidence format (A-E group), which uses a single sentence and a highly relevant graphic on each slide to ensure attention is drawn to the most important points in the presentation. Students took a multiple-choice pre-test, attended lecture, and then completed a take-home assignment. All students then completed an online multiple-choice post-test and, one month later, a different online multiple-choice test to evaluate retention. Groups did not differ on pre-test, assignment, or post-test scores, and both groups showed significant gains from pre-test to post-test and from pre-test to retention test. However, the T group showed significant decline from post-test to retention test, while the A-E group did not. Short-term differences between slide designs were most likely unaffected due to required coursework immediately after lecture, but retention of material was superior with the assertion-evidence slide design.

Soft wheat and flour products methods review: solvent retention capacity equation correction

USDA-ARS?s Scientific Manuscript database

This article discusses the results of a significant change to calculations made within AACCI Approved methods 56-10 and 56-11, the Alkaline Water Retention Capacity (AWRC) test and the Solvent Retention Capacity (SRC) test. The AACCI Soft Wheat and Flour Products Technical Committee reviewed propos...

The impact of sleep on true and false memory across long delays.

PubMed

Pardilla-Delgado, Enmanuelle; Payne, Jessica D

2017-01-01

While the influence of sleep on memory has a long history, sleep's role in the formation of false memories is less clear. Moreover, virtually nothing is known about the development of false memories beyond delays of about 12h. Here, for the first time, we assess post-sleep development of true and false memories across longer delay intervals of 24 and 48h. Although technically a false memory, remembering information that is related to the theme, or gist, of an experience can be considered an adaptive process. Some evidence suggests that sleep, compared to a wake period, increases both true and gist-based false memories in the Deese-Roediger-McDermott (DRM) task, but not all studies have returned this result, and most studies cannot rule out the possibility that sleep is merely protecting the information from interference, as opposed to actively aiding its consolidation. Here, to equate amount of time spent awake and asleep across groups, we assess how the positioning of sleep relative to memory encoding impacts retention across longer delays of 24 and 48h. Participants encoded 16 DRM lists in the morning (WAKE 1st Groups) or evening (SLEEP 1st Groups), and were tested either 24 or 48h later at the same time of day. Results demonstrate that true memory is better when participants sleep soon after learning. Sleeping first also increased false memory, but only in low performers. Importantly, and similar to previous studies, we found a negative correlation between slow-wave sleep (SWS) and false memory, suggesting that SWS may be detrimental for semantic/gist processing. Copyright © 2016 Elsevier Inc. All rights reserved.

Non-goal-directed recall of specific events in apes after long delays.

PubMed

Lewis, Amy; Call, Josep; Berntsen, Dorthe

2017-07-12

We examined if apes spontaneously remember one-time, distinctive events across long delays when probed by discriminant cues. Apes witnessed an experimenter hide a cache of food, which they could then retrieve. They retrieved one of two food types; one more distinctive than the other. Two, 10 or 50 weeks later, the apes returned to the same enclosure and found a piece of the previously hidden food on the ground. An experimenter who had not hidden the food was also present. Apes immediately searched the location where the food was previously hidden (no food was here), showing recall of the event. One week later, apes returned to the same enclosure, with the same food on the ground, but now the experimenter that had hidden the food was present. Again, apes immediately searched the hiding location. Apes that had not witnessed the hiding event did not search. There was no significant effect of food type, and retention declined from exposure to the two-week delay, then levelled, consistent with the forgetting curve in humans (Ebbinghaus, H. 1964 Memory: a contribution to experimental psychology (transl. H.A. Ruger & C.E. Bussenvis). New York, NY: Dover. (Original work published 1885.)). This is the first study to show apes can recall a one-time, non-goal-directed event longer than two weeks ago and that apes' recall declines in accordance with a standard retention function. © 2017 The Author(s).

Learning and memory performance in breast cancer survivors 2 to 6 years post-treatment: the role of encoding versus forgetting.

PubMed

Root, James C; Andreotti, Charissa; Tsu, Loretta; Ellmore, Timothy M; Ahles, Tim A

2016-06-01

Our previous retrospective analysis of clinically referred breast cancer survivors' performance on learning and memory measures found a primary weakness in initial encoding of information into working memory with intact retention and recall of this same information at a delay. This suggests that survivors may misinterpret cognitive lapses as being due to forgetting when, in actuality, they were not able to properly encode this information at the time of initial exposure. Our objective in this study was to replicate and extend this pattern of performance to a research sample to increase the generalizability of this finding in a sample in which subjects were not clinically referred for cognitive issues. We contrasted learning and memory performance between breast cancer survivors on endocrine therapy 2 to 6 years post-treatment with age- and education-matched healthy controls. We then stratified lower- and higher-performing breast cancer survivors to examine specific patterns of learning and memory performance. Contrasts were generated for four aggregate visual and verbal memory variables from the California Verbal Learning Test-2 (CVLT-2) and the Brown Location Test (BLT): Single-trial Learning: Trial 1 performance, Multiple-trial Learning: Trial 5 performance, Delayed Recall: Long-delay Recall performance, and Memory Errors: False-positive errors. As predicted, breast cancer survivors' performance as a whole was significantly lower on Single-trial Learning than the healthy control group but exhibited no significant difference in Delayed Recall. In the secondary analysis contrasting lower- and higher-performing survivors on cognitive measures, the same pattern of lower Single-trial Learning performance was exhibited in both groups, with the additional finding of significantly weaker Multiple-trial Learning performance in the lower-performing breast cancer group and intact Delayed Recall performance in both groups. As with our earlier finding of weaker initial encoding with intact recall in a cohort of clinically referred breast cancer survivors, our results indicate this same profile in a research sample of breast cancer survivors. Further, when the breast cancer group was stratified by lower and higher performance, both groups exhibited significantly lower performance on initial encoding, with more pronounced encoding weakness in the lower-performing group. As in our previous research, survivors did not lose successfully encoded information over longer delays, either in the lower- or higher-performing group, again arguing against memory decay in survivors. The finding of weaker initial encoding of information together with intact delayed recall in survivors points to specific treatment interventions in rehabilitation of cognitive dysfunction. The finding of weaker initial encoding of information together with intact delayed recall in survivors points to specific treatment interventions in rehabilitation of cognitive dysfunction and is discussed.

The effect of inquiry based science instruction on student understanding

NASA Astrophysics Data System (ADS)

Nail, Jessica Lynette

According to the TIMSS Study (2007), the United States is falling behind in the subjects of math and science. In order for the students in the United States to develop scientific literacy and remain competitive globally, inquiry must be the priority when teaching science (NRC, 1996; AAAS, 1990). The main purpose of this research was to see if inquiry-based instruction in the science classroom had a significant effect on student understanding and retention of information in a rural school in Virginia. The effect of inquiry-based science instruction on gender was also examined. The researcher implemented a four-week, inquiry-based unit on Virginia Sol 6.7, written in the 5 E learning style to 358 sixth-grade students and compared their posttest gains and delayed posttest scores to a control group consisting of 268 students. The control group received traditional teaching methods. The results for the posttest gains produced a p = 0.01. Therefore, there was a significant difference in the experimental group, which received the treatment, when compared to the control group, which did not receive treatment. A t test was also used to compare the delayed test scores of the experimental group to the control group. The results showed a p < 0.0001 when comparing the experimental group, which received the four-week inquiry-based science instruction treatment, to the control, which did not receive the treatment. This t test showed a very highly significant difference between the experimental group and the control group. Based on these results, it is imperative that Virginia begin implementing inquiry-based instruction in the science classroom.

Delay test generation for synchronous sequential circuits

NASA Astrophysics Data System (ADS)

Devadas, Srinivas

1989-05-01

We address the problem of generating tests for delay faults in non-scan synchronous sequential circuits. Delay test generation for sequential circuits is a considerably more difficult problem than delay testing of combinational circuits and has received much less attention. In this paper, we present a method for generating test sequences to detect delay faults in sequential circuits using the stuck-at fault sequential test generator STALLION. The method is complete in that it will generate a delay test sequence for a targeted fault given sufficient CPU time, if such a sequence exists. We term faults for which no delay test sequence exists, under out test methodology, sequentially delay redundant. We describe means of eliminating sequential delay redundancies in logic circuits. We present a partial-scan methodology for enhancing the testability of difficult-to-test of untestable sequential circuits, wherein a small number of flip-flops are selected and made controllable/observable. The selection process guarantees the elimination of all sequential delay redundancies. We show that an intimate relationship exists between state assignment and delay testability of a sequential machine. We describe a state assignment algorithm for the synthesis of sequential machines with maximal delay fault testability. Preliminary experimental results using the test generation, partial-scan and synthesis algorithm are presented.

Rigidity and retention of root canal posts.

PubMed

Purton, D G; Chandler, N P; Love, R M

1998-03-28

To test the rigidity and the retention into roots of parallel root canal posts, one a spiral vented titanium post and the other a spiral serrated, hollow, stainless steel post. A serrated, stainless steel post was used as the control. A three-point bending test was used to test rigidity. To test retention, ten posts of each type were cemented into the roots of extracted teeth with a resin cement and the tensile loads required to remove them were compared using Student's t and Mann-Whitney U tests. The serrated stainless steel posts were significantly more rigid than either of the other types. The titanium posts and the stainless steel hollow posts were not significantly different in rigidity. The serrated, stainless steel posts were significantly better retained than either of the other types. The titanium posts showed greater retention than the hollow posts. Within the limits of the study the stainless steel, serrated posts were superior to the two newer types in terms of rigidity and retention into roots.

Cross-Modal Decoding of Neural Patterns Associated with Working Memory: Evidence for Attention-Based Accounts of Working Memory

PubMed Central

Majerus, Steve; Cowan, Nelson; Péters, Frédéric; Van Calster, Laurens; Phillips, Christophe; Schrouff, Jessica

2016-01-01

Recent studies suggest common neural substrates involved in verbal and visual working memory (WM), interpreted as reflecting shared attention-based, short-term retention mechanisms. We used a machine-learning approach to determine more directly the extent to which common neural patterns characterize retention in verbal WM and visual WM. Verbal WM was assessed via a standard delayed probe recognition task for letter sequences of variable length. Visual WM was assessed via a visual array WM task involving the maintenance of variable amounts of visual information in the focus of attention. We trained a classifier to distinguish neural activation patterns associated with high- and low-visual WM load and tested the ability of this classifier to predict verbal WM load (high–low) from their associated neural activation patterns, and vice versa. We observed significant between-task prediction of load effects during WM maintenance, in posterior parietal and superior frontal regions of the dorsal attention network; in contrast, between-task prediction in sensory processing cortices was restricted to the encoding stage. Furthermore, between-task prediction of load effects was strongest in those participants presenting the highest capacity for the visual WM task. This study provides novel evidence for common, attention-based neural patterns supporting verbal and visual WM. PMID:25146374

Learning and extinction of a passive avoidance response in mice with high levels of predisposition to catalepsy.

PubMed

Dubrovina, N I; Zinov'ev, D R; Zinov'eva, D V; Kulikov, A V

2009-06-01

This report presents results obtained from comparative analysis of learning and the dynamics of extinction of a conditioned passive avoidance response in ASC mice, which were bred for a high level of predisposition to catalepsy, and in CBA and AKR mice. The following findings were obtained: 1) impairments to the extinction of the memory of fear represent an important symptom of depression in ASC mice; 2) extinction is delayed in CBA mice; and 3) new inhibitory learning occurs quickly in AKR mice. Prolonged retention of the fear memory in ASC mice appears to be related to increased anxiety on prolonged testing without a punishment. The deficit of inhibition of the fear reaction in ASC mice allows this strain to be regarded as a genetic model of depression.

Retention of storage quality and post-refrigeration shelf-life extension of plum (Prunus domestica L.) cv. Santa Rosa using combination of carboxymethyl cellulose (CMC) coating and gamma irradiation

NASA Astrophysics Data System (ADS)

Hussain, Peerzada R.; Suradkar, Prashant P.; Wani, Ali M.; Dar, Mohd A.

2015-02-01

Carboxymethyl cellulose (CMC) coatings alone and in combination with gamma irradiation was tested for maintaining the storage quality and extending shelf-life of plum. Matured green plums were CMC coated at levels 0.5-1.0% w/v and gamma irradiated at 1.5 kGy. The treated fruit including control was stored under ambient (temperature 25±2 °C, RH 70%) and refrigerated (temperature 3±1 °C, RH 80%) conditions. In fruits treated with individual treatments of 1.0% w/v CMC; 1.5 kGy irradiation and combination of 1.0% w/v CMC and 1.5 kGy irradiation, no decay was recorded up to 11, 17 and 21 days of ambient storage. Irradiation alone at 1.5 kGy gave 8 days extension in shelf-life of plum compared to 5 days by 1.0% w/v CMC coating following 45 days of refrigeration. All combinatory treatments of CMC coating and irradiation proved beneficial in maintaining the storage quality as well as delaying the decaying of plum during post-refrigerated storage at 25±2 °C, RH 70% but, combination of CMC at 1.0% w/v and 1.5 kGy irradiation was found significantly (p≤0.05) superior to all other treatments in maintaining the storage quality and delaying the decaying of plum. CMC coating of plums at 1.0% w/v followed by irradiation at 1.5 kGy resulted in chlorophyll retention of 19.4% after 16 days compared to 10% in control after 8 days of ambient storage. Under refrigerated conditions, same treatment gave retention of 67.6% in chlorophyll compared to 10.6% in control after 35 days of storage. The above combinatory treatment resulted in extension of 11 days in shelf-life of plum during post-refrigerated storage at 25±2 °C, RH 70% following 45 days of refrigeration. Based on microbial analysis, irradiation alone at 1.5 kGy and in combination with 1.0% w/v CMC resulted in 2.0 and 1.8 log reduction in yeast and mold count of plum fruit after 20 and 35 days of ambient and refrigerated storage, thereby ensuring consumer safety.

Effects of Static Visuals and Computer-Generated Animations in Facilitating Immediate and Delayed Achievement in the EFL Classroom

ERIC Educational Resources Information Center

Lin, Huifen; Chen, Tsuiping; Dwyer, Francis M.

2006-01-01

The purpose of this experimental study was to compare the effects of using static visuals versus computer-generated animation to enhance learners' comprehension and retention of a content-based lesson in a computer-based learning environment for learning English as a foreign language (EFL). Fifty-eight students from two EFL reading sections were…

The Relationship of Training in Self-Generated Questioning with Passage Difficulty and Immediate and Delayed Retention.

ERIC Educational Resources Information Center

Balajthy, Ernest

A study was conducted to determine if covert reader-generation of interspersed prequestions would affect recall of science-oriented prose. Sixty college freshmen in a basic skills reading course were divided into three groups: Group I received 5 hours of training and practive in the construction of self-generated questions, including recognition…

Collaborative Testing: An Effective Invitational Strategy for High-Stakes Testing in Nursing.

PubMed

Green, Rebecca; Worthey, Terri; Kerven, Jenny

2018-05-01

A collaborative testing intervention was designed as an application of the invitational education model in an undergraduate nursing course. The purpose of this study was to evaluate the effect of collaborative testing on examination scores and knowledge retention of course content and to evaluate students' feelings about the collaborative testing process. A quasi-experimental design was used to evaluate the effect of collaborative testing on examination scores and knowledge retention among undergraduate nursing students in a public health course (N = 106). A descriptive survey was used to evaluate students' perceptions of the collaborative testing intervention. Collaborative testing increased examination scores and facilitated knowledge retention. Students' perceptions of the intervention were positive. Invitational strategies, such as collaborative testing, may result in measurably better outcomes, such as better examination scores and improved knowledge retention. Rigor does not need to be a barrier to invitational learning and, in fact, it may be complemented and enhanced by it. [J Nurs Educ. 2018;57(5):291-295.]. Copyright 2018, SLACK Incorporated.

Revisiting the rise and fall of false recall: presentation rate effects depend on retention interval.

PubMed

Smith, Troy A; Kimball, Daniel R

2012-01-01

Leading theories of false memory predict that veridical and false recall of lists of semantically associated words can be dissociated by varying the presentation speed during study. Specifically, as presentation rate increases from milliseconds to seconds, veridical recall is predicted to increase monotonically while false recall is predicted to show a rapid rise and then a slow decrease--a pattern shown by McDermott and Watson (2001) in a study using immediate recall tests. In three experiments we tested the generality of the effects of rapid presentation rates on veridical and false memory. In Experiments 1 and 2 participants exhibited high levels of false recall on a delayed recall test, even for very fast stimulus onset asynchronies (SOA)--contrary to predictions from leading theories of false memory. When we switched to an immediate recall test in Experiment 3 we replicated the pattern predicted by the theories and observed by McDermott and Watson. Follow-up analyses further showed that the relative output position of false recalls is not affected by presentation rate, contrary to predictions from fuzzy trace theory. Implications for theories of false memory, including activation monitoring theory and fuzzy trace theory, are discussed.

The neuropsychological differentiation of patients with very mild Alzheimer's disease and/or major depression.

PubMed

desRosiers, G; Hodges, J R; Berrios, G

1995-11-01

To evaluate the usefulness of standardized neuropsychological tests in the psychometric differentiation of patients with very mild or mild Alzheimer's Disease (AD) and/or major depression presenting in a tertiary clinic with memory/attention complaints. Controlled prospective clinicoexperimental design. Multidisciplinary Memory Clinic at Addenbroke's Hospital, Cambridge, England. Twenty-four patients with a clinical diagnosis of Alzheimer's disease (12 with major depression and 12 without), 12 patients with major depressive illness but without AD, and 12 healthy control subjects, all matched for age, sex, education levels, and estimates of premorbid intellectual potential. Mini-Mental State Examination (MMSE), Wechsler's Logical Memory (WLM) and Visual Reproduction (WVR), immediate and delayed reproduction, Wechsler's paired Associate Learning (WPAL), including the Easy and Hard subsets. Warrington's Recognition Memory for Faces (WRMF), Kendrick's Object Learning (KOLT) and Digit Copying (KDCT) Tests. Minimum 2-year follow-up diagnosis. Statistically, patients with very mild AD were distinguished clearly from those without AD on most tests of memory functions. Psychometrically, only KOLT and an index of retention on WLM and WVR were specific enough to avoid false positives, a requirement for second-stage tools. They also proved sensitive enough to suggest their role as first-stage instruments when screening for primary dementia in high-functioning patients scoring above the cut-point on MMSE. As efforts intensify to develop more powerful means to identify patients with Alzheimer's disease in its earliest stages, inclusion of specialist tests posing greater cognitive challenge than standard mental status scales has been one strategy. Our study explored how some of these neuropsychological tools behave psychometrically when analyzed on a single-case basis, and the results suggest a few are sensitive enough to boost detection above base rates alone while also being specific enough to reduce false alarms. Retention on Wechsler's Logical Memory and Visual Reproduction tasks and scores on Kendrick's Object Learning Test helped decrease the degree of ambiguity when cognitive profiles were used to distinguish depressed patients with Alzheimer disease from those without.

Retention of Prose Following Testing with Different Types of Tests.

ERIC Educational Resources Information Center

Duchastel, Philippe C.

1981-01-01

Taking a test on a passage one has just studied is known to enhance later retention. This effect was influenced by the type of initial test used. It was evident in the case of the initial short-answer test, but not in the case of multiple choice and free recall tests. (Author/RD)

Pharmacokinetics of gabapentin in a novel gastric-retentive extended-release formulation: comparison with an immediate-release formulation and effect of dose escalation and food.

PubMed

Chen, Cuiping; Cowles, Verne E; Hou, Eddie

2011-03-01

The objectives of the 3 phase I studies described herein were (1) to compare the pharmacokinetics of gabapentin delivered from a novel gastric-retentive dosage form vs an immediate-release formulation, (2) to assess the dose proportionality of the gastric-retentive extended-release formulation, and (3) to determine the effect of food on the pharmacokinetics of gabapentin delivered from this formulation. The time to reach maximum plasma concentration (t(max)) was extended for gabapentin delivered from the gastric-retentive extended-release formulation compared with the immediate-release formulation. A dose-related increase in both the maximum plasma concentration (C(max)) and the area under the plasma concentration-time curve (AUC) was observed as the gabapentin dose increased from 600 to 2400 mg. Fed status and increased fat content delayed t(max) and enhanced C(max) and AUC in proportion to the fat content. The pharmacokinetics of gabapentin delivered from this extended-release formulation allows a reduced dosing frequency while maintaining bioavailability and possibly diminishing the occurrence of adverse events attributable to a slower increase to the peak concentration compared with the immediate-release dosage form.

Improvement in the water retention characteristics of sandy loam soil using a newly synthesized poly(acrylamide-co-acrylic acid)/AlZnFe2O4 superabsorbent hydrogel nanocomposite material.

PubMed

Shahid, Shaukat Ali; Qidwai, Ansar Ahmad; Anwar, Farooq; Ullah, Inam; Rashid, Umer

2012-08-03

The use of some novel and efficient crop nutrient-based superabsorbent hydrogel nanocomposites (SHNCs), is currently becoming increasingly important to improve the crop yield and productivity, due to their water retention properties. In the present study a poly(Acrylamide-co-acrylic acid)/AlZnFe2O4 superabsorbent hydrogel nanocomposite was synthesized and its physical properties characterized using Energy Dispersive X-ray (EDX), FE-SEM and FTIR spectroscopic techniques. The effects of different levels of SHNC were studied to evaluate the moisture retention properties of sandy loam soil (sand 59%, silt 21%, clay 19%, pH 7.4, EC 1.92 dS/m). The soil amendment with 0.1, 0.2, 0.3 and 0.4 w/w% of SHNC enhanced the moisture retention significantly at field capacity compared to the untreated soil. Besides, in a separate experiment, seed germination and seedling growth of wheat was found to be notably improved with the application of SHNC. A delay in wilting of seedlings by 5-8 days was observed for SHNC-amended soil, thereby improving wheat plant growth and establishment.

Retention interval affects visual short-term memory encoding.

PubMed

Bankó, Eva M; Vidnyánszky, Zoltán

2010-03-01

Humans can efficiently store fine-detailed facial emotional information in visual short-term memory for several seconds. However, an unresolved question is whether the same neural mechanisms underlie high-fidelity short-term memory for emotional expressions at different retention intervals. Here we show that retention interval affects the neural processes of short-term memory encoding using a delayed facial emotion discrimination task. The early sensory P100 component of the event-related potentials (ERP) was larger in the 1-s interstimulus interval (ISI) condition than in the 6-s ISI condition, whereas the face-specific N170 component was larger in the longer ISI condition. Furthermore, the memory-related late P3b component of the ERP responses was also modulated by retention interval: it was reduced in the 1-s ISI as compared with the 6-s condition. The present findings cannot be explained based on differences in sensory processing demands or overall task difficulty because there was no difference in the stimulus information and subjects' performance between the two different ISI conditions. These results reveal that encoding processes underlying high-precision short-term memory for facial emotional expressions are modulated depending on whether information has to be stored for one or for several seconds.

Effectiveness of Computer Animation and Geometrical Instructional Model on Mathematics Achievement and Retention among Junior Secondary School Students

ERIC Educational Resources Information Center

Gambari, A. I.; Falode, C. O.; Adegbenro, D. A.

2014-01-01

This study investigated the effectiveness of computer animation and geometry instructional model on mathematics achievement and retention on Junior Secondary School Students in Minna, Nigeria. It also examined the influence of gender on students' achievement and retention. The research was a pre-test post-test experimental and control group…

Pilot Testing for Feasibility in a Study of Student Retention and Attrition in Online Undergraduate Programs

ERIC Educational Resources Information Center

Fraser, Joy; Fahlman, Dorothy; Arscott, Jane; Guillot, Isabelle

2018-01-01

Prior to undertaking a descriptive study on attrition and retention of students in two online undergraduate health administration and human service programs, a pilot test was conducted to assess the procedures for participant recruitment, usability of the survey questionnaire, and data collection processes. A retention model provided the…

Facilitators and barriers for retention in HIV care between testing and treatment in Asia—A study in Bangladesh, Indonesia, Lao, Nepal, Pakistan, Philippines and Vietnam

PubMed Central

Nampaisan, Oranuch; Marrone, Gaetano

2017-01-01

Introduction The need for efficient retention in HIV care is more evident than ever because of the expansion of earlier ART initiation and the shift towards ‘Test and Treat’. This study assesses factors affecting participation in the HIV care cascade among people living with HIV (PLHIV) in the Asia-Pacific Region. Methods A total of 7843 PLHIV aged 18–50 years were recruited using targeted and venue-based sampling between October 1, 2012, and May 31, 2013, across 59 sites in 7 countries (Bangladesh, Indonesia, Lao People's Democratic Republic (Lao PDR), Nepal, Pakistan, Philippines and Vietnam). Statistically significant associations between demographic and health system determinants, and various steps in the HIV care cascade were computed using a generalized structural equation model. Results A high proportion of PLHIV (40–51%) presented late for HIV care and delayed linkage to care in all seven countries. However, once PLHIV enrolled in care, retention in the various steps of the care cascade including adherence to antiretroviral treatment (ART) was satisfactory. The proportion still engaged in HIV care at 36 months post HIV diagnosis, varied from 78% in Nepal to >90% in Lao PDR. Similarly, the proportion of ART initiation who also were adherent to ART ranged from 91% in Bangladesh to >95% in Philippines/ Vietnam and from 70% in Lao PDR to 89% in the Philippines respectively. The following factors enhanced the likelihood of ART initiation and high adherence to HIV care and ART: good client-provider communication, high HIV treatment literacy, a referral from a health worker and TB/HIV co-infection. The following barriers were identified: young age, sex work, imprisonment, transgender identity, illiteracy, rural residence, alcohol/ injecting drug use, perceived poor health status, lack of health insurance, fear of confidentiality breach, self-referral for HIV testing, and public hospital as the place of HIV diagnosis. Conclusions HIV programme planners should ensure easy access to HIV testing and earlier linkage to HIV care among PLHIV. In addition, multiple socio-economic and health systems barriers need to be addressed along the HIV care cascade to reach the UNAIDS 90-90-90 target in the Asia-Pacific region. PMID:28459881

Brain Activity During the Encoding, Retention, and Retrieval of Stimulus Representations

PubMed Central

de Zubicaray, Greig I.; McMahon, Katie; Wilson, Stephen J.; Muthiah, Santhi

2001-01-01

Studies of delayed nonmatching-to-sample (DNMS) performance following lesions of the monkey cortex have revealed a critical circuit of brain regions involved in forming memories and retaining and retrieving stimulus representations. Using event-related functional magnetic resonance imaging (fMRI), we measured brain activity in 10 healthy human participants during performance of a trial-unique visual DNMS task using novel barcode stimuli. The event-related design enabled the identification of activity during the different phases of the task (encoding, retention, and retrieval). Several brain regions identified by monkey studies as being important for successful DNMS performance showed selective activity during the different phases, including the mediodorsal thalamic nucleus (encoding), ventrolateral prefrontal cortex (retention), and perirhinal cortex (retrieval). Regions showing sustained activity within trials included the ventromedial and dorsal prefrontal cortices and occipital cortex. The present study shows the utility of investigating performance on tasks derived from animal models to assist in the identification of brain regions involved in human recognition memory. PMID:11584070

Effects of a novel poly (AA-co-AAm)/AlZnFe₂O₄/potassium humate superabsorbent hydrogel nanocomposite on water retention of sandy loam soil and wheat seedling growth.

PubMed

Shahid, Shaukat Ali; Qidwai, Ansar Ahmad; Anwar, Farooq; Ullah, Inam; Rashid, Umer

2012-10-25

A novel poly(acrylic acid-co-acrylamide)AlZnFe₂O₄/potassium humate( )superabsorbent hydrogel nanocomposite (PHNC) was synthesized and its physical properties characterized using SEM, Energy Dispersive X-ray (EDX) and FTIR spectroscopic techniques. Air dried sandy loam soil was amended with 0.1 to 0.4 w/w% of PHNC to evaluate its soil moisture retention attributes. Effect of PHNC amendment on pH, electrical conductivity (EC), porosity, bulk density and hydraulic conductivity of sandy loam soil was also studied. The soil amendment with 0.1 to 0.4 w/w% of PHNC remarkably enhanced the moisture retention at field capacity as compared to the un-amended soils. Seed germination and seedling growth of wheat (Triticum aestivum L.) was considerably increased and a delay by 6-9 days in wilting of seedlings was observed in the soil amended with PHNC, resulting in improved wheat plant establishment and growth.

Spacing Repetitions Over Long Timescales: A Review and a Reconsolidation Explanation

PubMed Central

Smith, Christopher D.; Scarf, Damian

2017-01-01

Recent accounts of the spacing effect have proposed molecular explanations that explain spacing over short, but not long timescales. In the first half of this paper, we review research on the spacing effect that has employed spaces of 24 h or more across skill-related tasks, language-related tasks and generalization for adults and children. Throughout this review, we distinguish between learning and retention by defining learning (or acquisition) as performance at the end of training and retention as performance after a delay period. Using this distinction, we find age- and task-related differences in the manifestation of the spacing effect over long timescales. In the second half of this paper, we discuss a reconsolidation account of the spacing effect. In particular, we review the evidence that suggests the spacing of repetitions influences the subsequent consolidation and reconsolidation processes; we explain how a reconsolidation account may explain the findings for learning; the inverted-U curve for retention; and compare the reconsolidation account with previous consolidation accounts of the spacing effect. PMID:28676769

A new role for the architecture of microvillar actin bundles in apical retention of membrane proteins.

PubMed

Revenu, Céline; Ubelmann, Florent; Hurbain, Ilse; El-Marjou, Fatima; Dingli, Florent; Loew, Damarys; Delacour, Delphine; Gilet, Jules; Brot-Laroche, Edith; Rivero, Francisco; Louvard, Daniel; Robine, Sylvie

2012-01-01

Actin-bundling proteins are identified as key players in the morphogenesis of thin membrane protrusions. Until now, functional redundancy among the actin-bundling proteins villin, espin, and plastin-1 has prevented definitive conclusions regarding their role in intestinal microvilli. We report that triple knockout mice lacking these microvillar actin-bundling proteins suffer from growth delay but surprisingly still develop microvilli. However, the microvillar actin filaments are sparse and lack the characteristic organization of bundles. This correlates with a highly inefficient apical retention of enzymes and transporters that accumulate in subapical endocytic compartments. Myosin-1a, a motor involved in the anchorage of membrane proteins in microvilli, is also mislocalized. These findings illustrate, in vivo, a precise role for local actin filament architecture in the stabilization of apical cargoes into microvilli. Hence, the function of actin-bundling proteins is not to enable microvillar protrusion, as has been assumed, but to confer the appropriate actin organization for the apical retention of proteins essential for normal intestinal physiology.

In utero protein restriction causes growth delay and alters sperm parameters in adult male rats

PubMed Central

2011-01-01

Background Recent studies have supported the concept of "fetal programming" which suggests that during the intrauterine development the fetus may be programmed to develop diseases in adulthood. The possible effects of in utero protein restriction on sexual development of rat male offspring were evaluated in the present study. Methods Pregnant Wistar rats were divided into two experimental groups: one group treated with standard chow (SC, n = 8, 17% protein) and the other group treated with hypoproteic chow (HC, n = 10, 6% protein) throughout gestation. After gestation the two experimental groups received standard chow. To evaluate the possible late reproductive effects of in utero protein restriction, the male offspring of both groups were assessed at different phases of sexual development: prepubertal (30 days old); peripubertal (60 days old); adult (90 days old). Student's t-test and Mann-Whitney test were utilized. Differences were considered significant when p < 0.05. Results We found that in utero protein restriction reduced the body weight of male pups on the first postnatal day and during the different sexual development phases (prepubertal, peripubertal and adult). During adulthood, Sertoli cell number, sperm motility and sperm counts in the testis and epididymal cauda were also reduced in HC. Furthermore, the numbers of sperm presenting morphological abnormalities and cytoplasmic drop retention were higher in HC. Conclusions In conclusion, in utero protein restriction, under these experimental conditions, causes growth delay and alters male reproductive-system programming in rats, suggesting impairment of sperm quality in adulthood. PMID:21702915

In utero protein restriction causes growth delay and alters sperm parameters in adult male rats.

PubMed

Toledo, Fabíola C; Perobelli, Juliana E; Pedrosa, Flávia P C; Anselmo-Franci, Janete A; Kempinas, Wilma D G

2011-06-24

Recent studies have supported the concept of "fetal programming" which suggests that during the intrauterine development the fetus may be programmed to develop diseases in adulthood. The possible effects of in utero protein restriction on sexual development of rat male offspring were evaluated in the present study. Pregnant Wistar rats were divided into two experimental groups: one group treated with standard chow (SC, n = 8, 17% protein) and the other group treated with hypoproteic chow (HC, n = 10, 6% protein) throughout gestation. After gestation the two experimental groups received standard chow. To evaluate the possible late reproductive effects of in utero protein restriction, the male offspring of both groups were assessed at different phases of sexual development: prepubertal (30 days old); peripubertal (60 days old); adult (90 days old). Student's t-test and Mann-Whitney test were utilized. Differences were considered significant when p < 0.05. We found that in utero protein restriction reduced the body weight of male pups on the first postnatal day and during the different sexual development phases (prepubertal, peripubertal and adult). During adulthood, Sertoli cell number, sperm motility and sperm counts in the testis and epididymal cauda were also reduced in HC. Furthermore, the numbers of sperm presenting morphological abnormalities and cytoplasmic drop retention were higher in HC. In conclusion, in utero protein restriction, under these experimental conditions, causes growth delay and alters male reproductive-system programming in rats, suggesting impairment of sperm quality in adulthood.

PKMζ Differentially Utilized between Sexes for Remote Long-Term Spatial Memory

PubMed Central

Sebastian, Veronica; Vergel, Tatyana; Baig, Raheela; Schrott, Lisa M.; Serrano, Peter A.

2013-01-01

It is well established that male rats have an advantage in acquiring place-learning strategies, allowing them to learn spatial tasks more readily than female rats. However many of these differences have been examined solely during acquisition or in 24h memory retention. Here, we investigated whether sex differences exist in remote long-term memory, lasting 30d after training, and whether there are differences in the expression pattern of molecular markers associated with long-term memory maintenance. Specifically, we analyzed the expression of protein kinase M zeta (PKMζ) and the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluA2. To adequately evaluate memory retention, we used a robust training protocol to attenuate sex differences in acquisition and found differential effects in memory retention 1d and 30d after training. Female cohorts tested for memory retention 1d after 60 training trials outperformed males by making significantly fewer reference memory errors at test. In contrast, male cohorts tested 30d after 60 training trials outperformed females of the same condition, making fewer reference memory errors and achieving significantly higher retention test scores. Furthermore, given 60 training trials, females tested 30d later showed significantly worse memory compared to females tested 1d later, while males tested 30d later did not differ from males tested 1d later. Together these data suggest that with robust training males do no retain spatial information as well as females do 24h post-training but maintain this spatial information for longer. Males also showed a significant increase in synaptic PKMζ expression and a positive correlation with retention test scores, while females did not. Interestingly, both sexes showed a positive correlation between retention test scores and synaptic GluA2 expression. Furthermore, the increased expression of synaptic PKMζ, associated with male memory but not with female memory, identifies another potential sex-mediated difference in memory processing. PMID:24244733

Clinical trials: the challenge of recruitment and retention of participants.

PubMed

Gul, Raisa B; Ali, Parveen A

2010-01-01

This article, based on the available literature, attempts to discuss the importance of recruitment and retention of research participants, the associated barriers and challenges, and various strategies to overcome these barriers. The inability to recruit and retain the required participants in a research project poses serious threats to both the internal and the external validity of a research study. Despite serious implications, the issues of recruitment and retention do not receive due attention in research and publications. Literature suggests a lack of coordinated efforts to collect information on the outcomes of recruitment experiences in clinical trials and population studies. Studies often mention the number of participants who refuse to participate; however, the majority of the studies often fail to mention the specific reasons insufficient recruitment or retention of the participants. A methodological paper. Various participant-, context-, environment- and research-related factors are examined that affect the phenomenon of recruitment and retention of the participants in a study. Delayed or inefficient recruitment also has financial and ethical implications. Although there are many pieces of information scattered throughout academic journals on recruitment and retention of participants in research, few authors have dealt with the issue holistically. It is imperative for researchers to understand the importance of recruitment and retention of research participants, the associated barriers and challenges, and various strategies to overcome these barriers. Appropriate recording and reporting of the problems faced while recruiting and retaining the participants in research studies can help not only in understating the challenge, but will also help in devising the strategies to overcome this problem. This article was an attempt to synthesise and review the available literature on recruitment and retention issues, which demand extensive theoretical and conceptual thinking as part of the research design. An understanding of the challenges and issues related to recruitment and retention can help researchers to think ahead about the strategies to overcome these issues and consequently save the time and energy of the participants, researchers and funding agencies.

Clinical progression, acute urinary retention, prostate-related surgeries, and costs in patients with benign prostatic hyperplasia taking early versus delayed combination 5α-reductase inhibitor therapy and α-blocker therapy: a retrospective analysis.

PubMed

Morlock, Robert; Goodwin, Bridgett; Gomez Rey, Gabriel; Eaddy, Michael

2013-05-01

Two previous retrospective database analyses compared early combination therapy with an α-blocker (AB) and 5-α reductase inhibitor (5-ARI) to delayed combination therapy and found that patients receiving the delayed combination therapy were more likely to have clinical progression, acute urinary retention (AUR), and surgery. Although these studies indicate the clinical benefits of early treatment, both studies failed to take into account important baseline clinical measures, such as prostate-specific antigen (PSA) values. This study was designed to compare clinical and cost differences in men with benign prostatic hyperplasia (BPH) who initiated early versus delayed combination therapy with a 5-ARI + an AB, factoring in baseline PSA values. This retrospective claims data analysis assessed data from >14 million US men with linked medical data, pharmacy data, laboratory results, and enrollment information from January 1, 2000, to December 31, 2009. Men aged 50 or older and treated for BPH with a 5-ARI + an AB were identified. Patients were required to be eligible for services at least 6 months before and 12 months after the index medication date. Patients were assigned to 1 of 2 treatment groups based on therapy (early or delayed) and 3 cohorts based on availability of PSA laboratory values (patients with a PSA value, patients with a PSA value >1.5 and <10, and all patients). Using a logistic model, the likelihood of clinical progression (defined as the occurrence of AUR or prostate surgery) during the 12 months after the date of first prescription fill was compared between BPH patients receiving early versus delayed combination therapy. BPH-related medical costs (excluding pharmacy costs) were assessed using generalized linear models. Among the 13,551 patients identified for study inclusion, the highest risks for clinical progression, AUR, and prostate-related surgery were consistently demonstrated in patients with a PSA >1.5 and <10. Across all 3 cohorts, the delayed combination-treatment group was more likely to have clinical progression, AUR, and prostate-related surgeries versus the early combination-treatment group. The incremental difference in BPH-related costs between the delayed and early combination-treatment groups was $190 per patient overall; the greatest incremental difference ($397) was observed in patients with PSA >1.5 and <10. The results suggest that early initiation of combination therapy with 5-ARI + an AB, compared with delayed initiation, can reduce the risks for clinical progression, AUR, and prostate-related surgeries, as well as BPH-related medical costs, in patients with BPH. Copyright © 2013 Elsevier HS Journals, Inc. All rights reserved.

Age differences in fear retention and extinction in male Sprague-Dawley rats: Effects of ethanol challenge during conditioning

PubMed Central

Broadwater, Margaret; Spear, Linda P.

2013-01-01

Pavlovian fear conditioning is an ideal model to investigate how learning and memory are influenced by alcohol use during adolescence because the neural mechanisms involved have been studied extensively. In Exp 1, adolescent and adult male Sprague-Dawley rats were non-injected or injected with saline, 1 or 1.5 g/kg ethanol intraperitoneally 10 minutes prior to tone or context conditioning. Twenty-four hours later, animals were tested for tone or context retention and extinction, with examination of extinction retention conducted 24 hours thereafter. In Exp 2, a context extinction session was inserted between the tone conditioning and the tone fear retention/extinction days to reduce pre-CS baseline freezing levels at test. Basal levels of acquisition, fear retention, extinction, and extinction retention after tone conditioning were similar between adolescent and adult rats. In contrast adolescents showed faster context extinction than adults, while again not differing from adults during context acquisition, retention or extinction retention. In terms of ethanol effects, adolescents were less sensitive to ethanol-induced context retention deficits than adults. No age differences emerged in terms of tone fear retention, with ethanol disrupting tone fear retention at both ages in Exp1, but at neither age in Exp 2, a difference seemingly due to group differences in pre-CS freezing during tone testing in Exp 1, but not Exp 2. These results suggest that age differences in the acute effects of ethanol on cognitive function are task-specific, and provide further evidence for age differences cognitive functioning in a task thought to be hippocampally-related. PMID:23810415

Retention Load of Telescopic Crowns with Different Taper Angles between Cobalt-Chromium and Polyetheretherketone Made with Three Different Manufacturing Processes Examined by Pull-Off Test.

PubMed

Wagner, Christina; Stock, Veronika; Merk, Susanne; Schmidlin, Patrick R; Roos, Malgorzata; Eichberger, Marlis; Stawarczyk, Bogna

2018-02-01

To investigate the retention loads of differently fabricated secondary telescopic polyetheretherketone (PEEK) crowns on cobalt-chromium primary crowns with different tapers. Cobalt-chromium primary crowns with 0°, 1°, and 2° tapers were constructed, milled, and sintered. Corresponding secondary crowns were fabricated by milling, pressing from pellets, and pressing from granules. For these nine test groups, the pull-off tests of each crown combination were performed 20 times, and the retention loads were measured (Zwick 1445, 50 mm/min). Data were analyzed using linear regression, covariance analysis, mixed models, Kruskal-Wallis, and Mann-Whitney U-test, together with the Benferroni-Holm correction. The mixed models covariance analysis reinforced stable retention load values (p = 0.162) for each single test sequence. There was no interaction between the groups and the separation cycles (p = 0.179). Milled secondary crowns with 0° showed the lowest mean retention load values compared to all tested groups (p = 0.003) followed by those pressed form pellets with 1°. Regarding the different tapers, no effect of manufacturing method on the results was observed within 1° and 2° groups (p = 0.540; p = 0.052); however, among the 0° groups, the milled ones showed significantly the lowest retention load values (p = 0.002). Among the manufacturing methods, both pressed groups showed no impact of taper on the retention load values (p > 0.324 and p > 0.123, respectively), whereas among the milled secondary crowns, the 0° taper showed significantly lower retention load values than the 1° and 2° taper (p < 0.002). Based on these results, telescopic crowns made of PEEK seem to show stable retention load values for each test sequence; however, data with thermo-mechanical aging are still required. In addition, further developments in CAD/CAM manufacturing of PEEK materials for telescopic crowns are warranted, especially for 0°. © 2016 by the American College of Prosthodontists.

High-fidelity simulation versus case-based discussion for teaching medical students in Brazil about pediatric emergencies.

PubMed

Couto, Thomaz Bittencourt; Farhat, Sylvia C L; Geis, Gary L; Olsen, Orjan; Schvartsman, Claudio

2015-06-01

To compare high-fidelity simulation with case-based discussion for teaching medical students about pediatric emergencies, as assessed by a knowledge post-test, a knowledge retention test and a survey of satisfaction with the method. This was a non-randomized controlled study using a crossover design for the methods, as well as multiple-choice questionnaire tests and a satisfaction survey. Final-year medical students were allocated into two groups: group 1 participated in an anaphylaxis simulation and a discussion of a supraventricular tachycardia case, and conversely, group 2 participated in a discussion of an anaphylaxis case and a supraventricular tachycardia simulation. Students were tested on each theme at the end of their rotation (post-test) and 4-6 months later (retention test). Most students (108, or 66.3%) completed all of the tests. The mean scores for simulation versus case-based discussion were respectively 43.6% versus 46.6% for the anaphylaxis pre-test (p=0.42), 63.5% versus 67.8% for the post-test (p=0.13) and 61.5% versus 65.5% for the retention test (p=0.19). Additionally, the mean scores were respectively 33.9% versus 31.6% for the supraventricular tachycardia pre-test (p=0.44), 42.5% versus 47.7% for the post-test (p=0.09) and 41.5% versus 39.5% for the retention test (p=0.47). For both themes, there was improvement between the pre-test and the post-test (p<0.05), and no significant difference was observed between the post-test and the retention test (p>0.05). Moreover, the satisfaction survey revealed a preference for simulation (p<0.001). As a single intervention, simulation is not significantly different from case-based discussion in terms of acquisition and retention of knowledge but is superior in terms of student satisfaction.

High-fidelity simulation versus case-based discussion for teaching medical students in Brazil about pediatric emergencies

PubMed Central

Couto, Thomaz Bittencourt; Farhat, Sylvia C.L.; Geis, Gary L; Olsen, Orjan; Schvartsman, Claudio

2015-01-01

OBJECTIVE: To compare high-fidelity simulation with case-based discussion for teaching medical students about pediatric emergencies, as assessed by a knowledge post-test, a knowledge retention test and a survey of satisfaction with the method. METHODS: This was a non-randomized controlled study using a crossover design for the methods, as well as multiple-choice questionnaire tests and a satisfaction survey. Final-year medical students were allocated into two groups: group 1 participated in an anaphylaxis simulation and a discussion of a supraventricular tachycardia case, and conversely, group 2 participated in a discussion of an anaphylaxis case and a supraventricular tachycardia simulation. Students were tested on each theme at the end of their rotation (post-test) and 4–6 months later (retention test). RESULTS: Most students (108, or 66.3%) completed all of the tests. The mean scores for simulation versus case-based discussion were respectively 43.6% versus 46.6% for the anaphylaxis pre-test (p=0.42), 63.5% versus 67.8% for the post-test (p=0.13) and 61.5% versus 65.5% for the retention test (p=0.19). Additionally, the mean scores were respectively 33.9% versus 31.6% for the supraventricular tachycardia pre-test (p=0.44), 42.5% versus 47.7% for the post-test (p=0.09) and 41.5% versus 39.5% for the retention test (p=0.47). For both themes, there was improvement between the pre-test and the post-test (p<0.05), and no significant difference was observed between the post-test and the retention test (p>0.05). Moreover, the satisfaction survey revealed a preference for simulation (p<0.001). CONCLUSION: As a single intervention, simulation is not significantly different from case-based discussion in terms of acquisition and retention of knowledge but is superior in terms of student satisfaction. PMID:26106956

Evaluation of retentive strength of four luting cements with stainless steel crowns in primary molars: An in vitro study.

PubMed

Parisay, Iman; Khazaei, Yegane

2018-01-01

Stainless steel crown (SSC) is the most reliable restoration for primary teeth with extensive caries. Retention is of great importance for a successful restoration and is provided by various factors such as luting cements. The aim of this study was to evaluate the retentive strength of SSC cemented with four different luting cements. In this in vitro study, A total of 55 extracted primary first molars were selected. Following crown selection and cementation (one with no cement and four groups cemented with resin, glass ionomer, zinc phosphate, and polycarboxylate), all the specimens were incubated and thermocycled in 5°C-55°C. Retentive properties of SSCs were tested with a mechanical test machine. First dislodgement of each specimen and full crown removal were recorded. One-way ANOVA test followed by least significant difference test and Kruskal-Wallis test was used for retentive strength comparison at the level of significance of P < 0.05. The results of the study showed that the specimens cemented with zinc phosphate exhibited higher retentive strength as compared to glass ionomer and polycarboxylate ( P < 0.001 and P = 0.023, respectively). Zinc phosphate cement showed the most promising results; thus, it can be preferably used for cementation of the teeth with no grossly broken down crowns.

The Baptist Health Nurse Retention Questionnaire: A Methodological Study, Part 1.

PubMed

Lengerich, Alexander; Bugajski, Andrew; Marchese, Matthew; Hall, Brittany; Yackzan, Susan; Davies, Claire; Brockopp, Dorothy

2017-05-01

The purposes of this study were to develop and test the Baptist Health Nurse Retention Questionnaire (BHNRQ) and examine the importance of nurse retention factors. Multiple factors, including increasing patient acuity levels, have led to concerns regarding nurse retention. An understanding of current factors related to retention is limited. To establish the psychometric properties of the BHNRQ, data were collected from 279 bedside nurses at a 391-bed, Magnet® redesignated community hospital. A principal component analysis was conducted to determine the subscale structure of the BHNRQ. Additional analyses were conducted related to content validity and test-retest reliability. The results of the principal components analysis revealed 3 subscales: nursing practice, management, and staffing. Analyses demonstrate that the BHNRQ is a reliable and valid instrument for measuring nurse retention factors. The BHNRQ was found to be a clinically useful instrument for measuring important factors related to nurse retention.

Scientific method by argumentation design: learning process for maintaining student’s retention

NASA Astrophysics Data System (ADS)

Siswanto; Yusiran; Asriyadin; Gumilar, S.; Subali, B.

2018-03-01

The purpose of this research describes the effect of scientific methods designed by argumentation in maintaining retention of pre-service physics teachers (students) in mechanical concept. This learning consists of five stages including the first two stages namely observing and questioning. While the next three stages of reasoning, trying, and communicating are made of argumentation design. To know the effectiveness of treatment, students are given pre-test and post-test in one time. On the other hand, students were given advanced post-test to know the durability of retention as many as four times in four months. The results show that there was mean difference between pre-test and post-test based on the Wilcoxon test (z = -3.4, p=0.001). While the effectiveness of treatment is in the high category based on normalized gain values ( = 0.86). Meanwhile, mean difference of all post-test is significantly different based on Analysis of Varian (F = 365.63, p = 0.00). However, in the fourth month, students retention rates began to stabilize based on Tuckey’s HSD (p=0.074) for comparison of mean difference between fourth and fifth post-test. Overall, learning designed can maintain students retention within 4 months after the learning finish.

Effects of Different Types of True-False Questions on Memory Awareness and Long-Term Retention

ERIC Educational Resources Information Center

Schaap, Lydia; Verkoeijen, Peter; Schmidt, Henk

2014-01-01

This study investigated the effects of two different true-false questions on memory awareness and long-term retention of knowledge. Participants took four subsequent knowledge tests on curriculum learning material that they studied at different retention intervals prior to the start of this study (i.e. prior to the first test). At the first and…

Retention of long-term interim restorations with sodium fluoride enriched interim cement

NASA Astrophysics Data System (ADS)

Strash, Carolyn

Purpose: Interim fixed dental prostheses, or "provisional restorations", are fabricated to restore teeth when definitive prostheses are made indirectly. Patients undergoing extensive prosthodontic treatment frequently require provisionalization for several months or years. The ideal interim cement would retain the restoration for as long as needed and still allow for ease of removal. It would also avoid recurrent caries by preventing demineralization of tooth structure. This study aims to determine if adding sodium fluoride varnish to interim cement may assist in the retention of interim restorations. Materials and methods: stainless steel dies representing a crown preparation were fabricated. Provisional crowns were milled for the dies using CAD/CAM technology. Crowns were provisionally cemented onto the dies using TempBond NE and NexTemp provisional cements as well as a mixture of TempBond NE and Duraphat fluoride varnish. Samples were stored for 24h then tested or thermocycled for 2500 or 5000 cycles before being tested. Retentive strength of each cement was recorded using a universal testing machine. Results: TempBond NE and NexTemp cements performed similarly when tested after 24h. The addition of Duraphat significantly decreased the retention when added to TempBond NE. NexTemp cement had high variability in retention over all tested time periods. Thermocycling for 2500 and 5000 cycles significantly decreased the retention of all cements. Conclusions: The addition of Duraphat fluoride varnish significantly decreased the retention of TempBond NE and is therefore not recommended for clinical use. Thermocycling significantly reduced the retention of TempBond NE and NexTemp. This may suggest that use of these cements for three months, as simulated in this study, is not recommended.

Pre-training evaluation and feedback improved skills retention of basic life support in medical students.

PubMed

Li, Qi; Zhou, Rong-hua; Liu, Jin; Lin, Jing; Ma, Er-Li; Liang, Peng; Shi, Ting-wei; Fang, Li-qun; Xiao, Hong

2013-09-01

Pre-training evaluation and feedback have been shown to improve medical students' skills acquisition of basic life support (BLS) immediately following training. The impact of such training on BLS skills retention is unknown. This study was conducted to investigate effects of pre-training evaluation and feedback on BLS skills retention in medical students. Three hundred and thirty 3rd year medical students were randomized to two groups, the control group (C group) and pre-training evaluation and feedback group (EF group). Each group was subdivided into four subgroups according to the time of retention-test (at 1-, 3-, 6-, 12-month following the initial training). After a 45-min BLS lecture, BLS skills were assessed (pre-training evaluation) in both groups before training. Following this, the C group received 45 min training. 15 min of group feedback corresponding to students' performance in pre-training evaluation was given only in the EF group that was followed by 30 min of BLS training. BLS skills were assessed immediately after training (post-test) and at follow up (retention-test). No skills difference was observed between the two groups in pre-training evaluation. Better skills acquisition was observed in the EF group (85.3 ± 7.3 vs. 68.1 ± 12.2 in C group) at post-test (p<0.001). In all retention-test, better skills retention was observed in each EF subgroup, compared with its paired C subgroup. Pre-training evaluation and feedback improved skills retention in the EF group for 12 months after the initial training, compared with the control group. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

How Do Tests and Summary Writing Tasks Enhance Long-Term Retention of Students with Different Levels of Test Anxiety?

ERIC Educational Resources Information Center

Mok, Wilson Shun; Chan, Winnie Wai

2016-01-01

Testing has been found to facilitate students' long-term retention of information. However, the learning performance of highly test-anxious students can be impaired by tests. Thus, these students may learn ineffectively in a testing context. By contrast, summary writing may not trigger test anxiety and is therefore another learning strategy to…

Leveling the playing field: attention mitigates the effects of intelligence on memory.

PubMed

Markant, Julie; Amso, Dima

2014-05-01

Effective attention and memory skills are fundamental to typical development and essential for achievement during the formal education years. It is critical to identify the specific mechanisms linking efficiency of attentional selection of an item and the quality of its memory retention. The present study capitalized on the spatial cueing paradigm to examine the role of selection via suppression in modulating children and adolescents' memory encoding. By varying a single parameter, the spatial cueing task can elicit either a simple orienting mechanism (i.e., facilitation) or one that involves both target selection and simultaneous suppression of competing information (i.e., IOR). We modified this paradigm to include images of common items in target locations. Participants were not instructed to learn the items and were not told they would be completing a memory test later. Following the cueing task, we imposed a 7-min delay and then asked participants to complete a recognition memory test. Results indicated that selection via suppression promoted recognition memory among 7-17year-olds. Moreover, individual differences in the extent of suppression during encoding predicted recognition memory accuracy. When basic cueing facilitated orienting to target items during encoding, IQ was the best predictor of recognition memory performance for the attended items. In contrast, engaging suppression (i.e., IOR) during encoding counteracted individual differences in intelligence, effectively improving recognition memory performance among children with lower IQs. This work demonstrates that engaging selection via suppression during learning and encoding improves memory retention and has broad implications for developing effective educational techniques. Copyright © 2014 Elsevier B.V. All rights reserved.

Leveling the playing field: Attention mitigates the effects of intelligence on memory

PubMed Central

Markant, Julie; Amso, Dima

2014-01-01

Effective attention and memory skills are fundamental to typical development and essential for achievement during the formal education years. It is critical to identify the specific mechanisms linking efficiency of attentional selection of an item and the quality of its memory retention. The present study capitalized on the spatial cueing paradigm to examine the role of selection via suppression in modulating children and adolescents’ memory encoding. By varying a single parameter, the spatial cueing task can elicit either a simple orienting mechanism (i.e., facilitation) or one that involves both target selection and simultaneous suppression of competing information (i.e., IOR). We modified this paradigm to include images of common items in target locations. Participants were not instructed to learn the items and were not told they would be completing a memory test later. Following the cueing task, we imposed a seven-minute delay and then asked participants to complete a recognition memory test. Results indicated that selection via suppression promoted recognition memory among 7-17 year-olds. Moreover, individual differences in the extent of suppression during encoding predicted recognition memory accuracy. When basic cueing facilitated orienting to target items during encoding, IQ was the best predictor of recognition memory performance for the attended items. In contrast, engaging suppression (i.e, IOR) during encoding counteracted individual differences in intelligence, effectively improving recognition memory performance among children with lower IQs. This work demonstrates that engaging selection via suppression during learning and encoding improves memory retention and has broad implications for developing effective educational techniques. PMID:24549142

A Testing Effect with Multimedia Learning

ERIC Educational Resources Information Center

Johnson, Cheryl I.; Mayer, Richard E.

2009-01-01

A testing effect occurs when a learner performs better on a retention test after studying the material and taking a practice-retention test than after studying the material twice. In the present study, 282 participants watched a narrated animation about lightning formation and then watched the presentation again (restudy), took a…

The Effect of Asymmetrical Sample Training on Retention Functions for Hedonic Samples in Rats

ERIC Educational Resources Information Center

Simmons, Sabrina; Santi, Angelo

2012-01-01

Rats were trained in a symbolic delayed matching-to-sample task to discriminate sample stimuli that consisted of the presence of food or the absence of food. Asymmetrical sample training was provided in which one group was initially trained with only the food sample and the other group was initially trained with only the no-food sample. In…

The Benefit of Directed Forgetting Persists After a Daytime Nap: The Role of Spindles and Rapid Eye Movement Sleep in the Consolidation of Relevant Memories.

PubMed

Blaskovich, Borbála; Szollosi, Ágnes; Gombos, Ferenc; Racsmány, Mihály; Simor, Péter

2017-03-01

We aimed to investigate the effect of directed forgetting instruction on memory retention after a 2-hour delay involving a daytime nap or an equivalent amount of time spent awake. We examined the associations between sleep-specific oscillations and the retention of relevant and irrelevant study materials. We applied a list-method directed forgetting paradigm manipulating the perceived relevance of previously encoded lists of words. Participants were randomly assigned to either a nap or an awake group, and to a remember or a forget subgroup. The remember and the forget subgroups were both instructed to study two consecutive lists of words, although, the forget subgroup was manipulated to forget the first list and memorize only the second one. Participants were 112 healthy individuals (44 men; Mage = 21.4 years, SD = 2.4). A significant directed forgetting effect emerged after a 2-hour delay both in the awake and sleep conditions; however, the effect was more pronounced within the sleep group. The benefit of directed forgetting, that is, relatively enhanced recall of relevant words in the forget group, was evidenced only in those participants that reached rapid eye movement (REM) phase. Non-rapid eye movement (NREM) sigma power was correlated with memory performance for the relevant (second) list, and sleep spindle amplitude was associated with the retention of both lists. These associations, however, were detected only within the forget subgroup. REM duration correlated with recall performance for the relevant (second) list within the forget subgroup, and with recall performance for the first list within the remember subgroup. A directed forgetting effect persists after a 2-hour delay spent awake or asleep. Spindle-related activity and subsequent REM sleep might selectively facilitate the processing of memories that are considered to be relevant for the future. © Sleep Research Society 2016. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Time-dependent differences in management and microbiology of orthopaedic internal fixation-associated infections: an observational prospective study with 229 patients.

PubMed

Kuehl, R; Tschudin-Sutter, S; Morgenstern, M; Dangel, M; Egli, A; Nowakowski, A; Suhm, N; Theilacker, C; Widmer, A F

2018-04-10

Little information has been published on orthopaedic internal fixation-associated infections. We aimed to analyse time-dependent microbiology, treatment, and outcome. Over a 10-year period, all consecutive patients with internal fixation-associated infections at the University Hospital of Basel, were prospectively followed and clinical, microbiological and outcome data were acquired. Infections were classified as early (0-2 weeks after implantation), delayed (3-10 weeks), and late (>10 weeks). Two hundred and twenty-nine patients were included, with a median follow-up of 773 days (IQR 334-1400). Staphylococcus aureus was the most prevalent pathogen (in 96/229 patients, 41.9%). Enterobacteriaceae were frequent in early infections (13/49, 26.5%), whereas coagulase-negative staphylococci (36/92, 39.1%), anaerobes (15/92, 16.3%) and streptococci (10/92, 10.9%) increased in late revisions. Failure was observed in 27/229 (11.7%). Implants were retained in 42/49 (85.7%) in early, in 51/88 (57.9%) in delayed, and in 9/92 (9.8%) in late revisions (p < 0.01). Early revisions failed in 6/49 (12.2%), delayed in 9/88 (10.2%), and late in 11/92 (13.0%) (p 0.81). Debridement and retention failed in 6/42 (14.3%) for early, in 6/51 (11.8%) for delayed, and in 3/9 (33.3%) for late revisions (p 0.21). Biofilm-active antibiotic therapy tailored to resistance correlated with improved outcome for late revisions failure (6/72, 7.7% versus 6/12, 50.0%; p < 0.01) but not for early revisions failure (5/38, 13.2% versus 1/11, 9.1%; p 1.0). Treatment of internal fixation-associated infections showed a high success rate of 87-90% over all time periods. Implant retention was highly successful in early and delayed infections but only limited in late infections. Copyright © 2018 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Regional hippocampal volumes and development predict learning and memory.

PubMed

Tamnes, Christian K; Walhovd, Kristine B; Engvig, Andreas; Grydeland, Håkon; Krogsrud, Stine K; Østby, Ylva; Holland, Dominic; Dale, Anders M; Fjell, Anders M

2014-01-01

The hippocampus is an anatomically and functionally heterogeneous structure, but longitudinal studies of its regional development are scarce and it is not known whether protracted maturation of the hippocampus in adolescence is related to memory development. First, we investigated hippocampal subfield development using 170 longitudinally acquired brain magnetic resonance imaging scans from 85 participants aged 8-21 years. Hippocampal subfield volumes were estimated by the use of automated segmentation of 7 subfields, including the cornu ammonis (CA) sectors and the dentate gyrus (DG), while longitudinal subfield volumetric change was quantified using a nonlinear registration procedure. Second, associations between subfield volumes and change and verbal learning/memory across multiple retention intervals (5 min, 30 min and 1 week) were tested. It was hypothesized that short and intermediate memory would be more closely related to CA2-3/CA4-DG and extended, remote memory to CA1. Change rates were significantly different across hippocampal subfields, but nearly all subfields showed significant volume decreases over time throughout adolescence. Several subfield volumes were larger in the right hemisphere and in males, while for change rates there were no hemisphere or sex differences. Partly in support of the hypotheses, greater volume of CA1 and CA2-3 was related to recall and retention after an extended delay, while longitudinal reduction of CA2-3 and CA4-DG was related to learning. This suggests continued regional development of the hippocampus across adolescence and that volume and volume change in specific subfields differentially predict verbal learning and memory over different retention intervals, but future high-resolution studies are called for. © 2014 S. Karger AG, Basel.

Temperament and impulsivity predictors of smoking cessation outcomes.

PubMed

López-Torrecillas, Francisca; Perales, José C; Nieto-Ruiz, Ana; Verdejo-García, Antonio

2014-01-01

Temperament and impulsivity are powerful predictors of addiction treatment outcomes. However, a comprehensive assessment of these features has not been examined in relation to smoking cessation outcomes. Naturalistic prospective study. Treatment-seeking smokers (n = 140) were recruited as they engaged in an occupational health clinic providing smoking cessation treatment between 2009 and 2013. Participants were assessed at baseline with measures of temperament (Temperament and Character Inventory), trait impulsivity (Barratt Impulsivity Scale), and cognitive impulsivity (Go/No Go, Delay Discounting and Iowa Gambling Task). The outcome measure was treatment status, coded as "dropout" versus "relapse" versus "abstinence" at 3, 6, and 12 months endpoints. Participants were telephonically contacted and reminded of follow-up face to face assessments at each endpoint. The participants that failed to answer the phone calls or self-reported discontinuation of treatment and failed to attend the upcoming follow-up session were coded as dropouts. The participants that self-reported continuing treatment, and successfully attended the upcoming follow-up session were coded as either "relapse" or "abstinence", based on the results of smoking behavior self-reports cross-validated with co-oximetry hemoglobin levels. Multinomial regression models were conducted to test whether temperament and impulsivity measures predicted dropout and relapse relative to abstinence outcomes. Higher scores on temperament dimensions of novelty seeking and reward dependence predicted poorer retention across endpoints, whereas only higher scores on persistence predicted greater relapse. Higher scores on the trait dimension of non-planning impulsivity but not performance on cognitive impulsivity predicted poorer retention. Higher non-planning impulsivity and poorer performance in the Iowa Gambling Task predicted greater relapse at 3 and 6 months and 6 months respectively. Temperament measures, and specifically novelty seeking and reward dependence, predict smoking cessation treatment retention, whereas persistence, non-planning impulsivity and poor decision-making predict smoking relapse.

Combine Flash-Based FPGA TID and Long-Term Retention Reliabilities Through VT Shift

NASA Astrophysics Data System (ADS)

Wang, Jih-Jong; Rezzak, Nadia; Dsilva, Durwyn; Xue, Fengliang; Samiee, Salim; Singaraju, Pavan; Jia, James; Nguyen, Victor; Hawley, Frank; Hamdy, Esmat

2016-08-01

Reliability test results of data retention and total ionizing dose (TID) in 65 nm Flash-based field programmable gate array (FPGA) are presented. Long-chain inverter design is recommended for reliability evaluation because it is the worst case design for both effects. Based on preliminary test data, both issues are unified and modeled by one natural decay equation. The relative contributions of TID induced threshold-voltage shift and retention mechanisms are evaluated by analyzing test data.

40 CFR 160.195 - Retention of records.

Code of Federal Regulations, 2012 CFR

2012-07-01

... obtained from mutagenicity tests, specimens of soil, water, and plants, and wet specimens of blood, urine... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Retention of records. 160.195 Section... LABORATORY PRACTICE STANDARDS Records and Reports § 160.195 Retention of records. (a) Record retention...

40 CFR 160.195 - Retention of records.

Code of Federal Regulations, 2014 CFR

2014-07-01

... obtained from mutagenicity tests, specimens of soil, water, and plants, and wet specimens of blood, urine... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Retention of records. 160.195 Section... LABORATORY PRACTICE STANDARDS Records and Reports § 160.195 Retention of records. (a) Record retention...

40 CFR 160.195 - Retention of records.

Code of Federal Regulations, 2013 CFR

2013-07-01

... obtained from mutagenicity tests, specimens of soil, water, and plants, and wet specimens of blood, urine... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Retention of records. 160.195 Section... LABORATORY PRACTICE STANDARDS Records and Reports § 160.195 Retention of records. (a) Record retention...

40 CFR 160.195 - Retention of records.

Code of Federal Regulations, 2011 CFR

2011-07-01

... obtained from mutagenicity tests, specimens of soil, water, and plants, and wet specimens of blood, urine... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Retention of records. 160.195 Section... LABORATORY PRACTICE STANDARDS Records and Reports § 160.195 Retention of records. (a) Record retention...

40 CFR 80.1348 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 17 2014-07-01 2014-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Sampling, Testing and Retention Requirements § 80.1348 What gasoline sample retention requirements...

40 CFR 80.1348 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 17 2013-07-01 2013-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Sampling, Testing and Retention Requirements § 80.1348 What gasoline sample retention requirements...

40 CFR 80.1348 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 16 2010-07-01 2010-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Sampling, Testing and Retention Requirements § 80.1348 What gasoline sample retention requirements...

40 CFR 80.1348 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 16 2011-07-01 2011-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Sampling, Testing and Retention Requirements § 80.1348 What gasoline sample retention requirements...

40 CFR 80.1348 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 17 2012-07-01 2012-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Sampling, Testing and Retention Requirements § 80.1348 What gasoline sample retention requirements...

Retention of veneered stainless steel crowns on replicated typodont primary incisors: an in vitro study.

PubMed

Guelmann, Marcio; Gehring, Daren F; Turner, Clara

2003-01-01

The purpose of this in vitro study was to determine the effect of crimping and cementation on retention of veneered stainless steel crowns. One hundred twenty crowns, 90 from 3 commercially available brands of veneered stainless steel crowns (Dura Crown, Kinder Krown, and NuSmile Primary Crown) and 30 (plain) Unitek stainless steel crowns were assessed for retention. An orthodontic wire was soldered perpendicular to the incisal edge of the crowns; the crowns were fitted to acrylic replicas of ideal crown preparations and were divided equally into 3 test groups: group 1--crowns were crimped only (no cement used); group 2--crowns were cemented only; and group 3--crowns were crimped and cemented to the acrylic replicas. An Instron machine recorded the amount of force necessary to dislodge the crowns and the results were statistically analyzed using 2-way ANOVA and Tukey honestly significant difference (HSD) test. Group 3 was statistically more retentive than groups 1 and 2. Group 2 was statistically more retentive than group 1 (P < .001). In group 1, Unitek crowns were statistically more retentive than the veneered crowns (P < .05). In group 2, NuSmile crowns showed statistically less retention values than all other crowns (P < .05). In group 3,Kinder Krown crowns showed statistically better retention rates than all other brands (P < .05). Significantly higher retention values were obtained for all brands tested when crimping and cement were combined. The crowns with veneer facings were significantly more retentive than the nonveneered ones when cement and crimping were combined.

Multiple foci of spatial attention in multimodal working memory.

PubMed

Katus, Tobias; Eimer, Martin

2016-11-15

The maintenance of sensory information in working memory (WM) is mediated by the attentional activation of stimulus representations that are stored in perceptual brain regions. Using event-related potentials (ERPs), we measured tactile and visual contralateral delay activity (tCDA/CDA components) in a bimodal WM task to concurrently track the attention-based maintenance of information stored in anatomically segregated (somatosensory and visual) brain areas. Participants received tactile and visual sample stimuli on both sides, and in different blocks, memorized these samples on the same side or on opposite sides. After a retention delay, memory was unpredictably tested for touch or vision. In the same side blocks, tCDA and CDA components simultaneously emerged over the same hemisphere, contralateral to the memorized tactile/visual sample set. In opposite side blocks, these two components emerged over different hemispheres, but had the same sizes and onset latencies as in the same side condition. Our results reveal distinct foci of tactile and visual spatial attention that were concurrently maintained on task-relevant stimulus representations in WM. The independence of spatially-specific biasing mechanisms for tactile and visual WM content suggests that multimodal information is stored in distributed perceptual brain areas that are activated through modality-specific processes that can operate simultaneously and largely independently of each other. Copyright © 2016 Elsevier Inc. All rights reserved.

Retention strength of impression materials to a tray material using different adhesive methods: an in vitro study.

PubMed

Marafie, Yousef; Looney, Stephen; Nelson, Steven; Chan, Daniel; Browning, William; Rueggeberg, Frederick

2008-12-01

A new self-stick adhesive system has been purported to eliminate the need to use chemical adhesives with plastic impression trays; however, no testing has confirmed the claim. The purpose of this study was to compare the in vitro retentive strength of impression materials to plastic substrates having conventional adhesive (CA) or the self-stick adhesive system, with and without mechanical retention. Three types of impression materials (irreversible hydrocolloid (IH), vinyl polysiloxane (VPS), and polyether (PE)) were applied to polystyrene disc-shaped surfaces (33.68 cm(2)) that were held on the arms of a universal testing machine. The appropriate CA or the self-stick adhesive system (Self-Stick Dots) (SSD) was applied to the plates, which had either no mechanical retention, or equally spaced mechanical perforations (n=4). An in vivo pilot test determined the appropriate rate of plate separation. Plates with impression material were lowered to provide 4 mm of space, the material set, and plates were separated using the appropriate speed. Force at first separation was divided by plate area (peak stress). Five replications per test condition were made, and results were analyzed using ANOVA and Bonferroni-adjusted t tests (alpha=.05). Within each impression material/test combination, stress using SSD was significantly lower than CA (P<.05). Mechanical retention did not always provide significantly greater strength. The combination of mechanical retention and CA yielded the highest strength within each material type, except for PE, for which nonmechanical and CA strength did not differ from that of mechanical and CA. Use of the self-stick adhesive system provided significantly lower retentive strength to plastic tray material than chemical adhesives for irreversible hydrocolloid, vinyl polysiloxane, and polyether.

Retention of Vaginal Breech Delivery Skills Taught in Simulation.

PubMed

Stone, Heather; Crane, Joan; Johnston, Kathy; Craig, Catherine

2018-02-01

The optimal frequency of conducting simulation training for high-acuity, low-frequency events in obstetrics and gynaecology residency programs is unknown. This study evaluated retention over time of vaginal breech delivery skills taught in simulation, by comparing junior and senior residents. In addition, the residents' subjective comfort level to perform this skill clinically was assessed. This prospective cohort study included 22 obstetrics and gynaecology residents in a Canadian residency training program. Digital recordings were completed for pre-training, immediate post-training, and delayed (10-26 weeks later) post-training intervals of a vaginal breech delivery simulation, with skill assessment by a blinded observer using a binary checklist. Residents also completed questionnaires to assess their subjective comfort level at each interval. Junior and senior residents had significant improvements in vaginal breech delivery skills from the pre-training assessment to both the immediate post-training assessment (junior, P <0.001; senior, P <0.001) and the delayed post-training assessment (P <0.001 and P = 0.001, respectively). There was a significant decline in skills between the immediate and delayed post-training sessions for junior and senior residents (P = 0.003 and P <0.001, respectively). Both junior and senior residents gained more comfort immediately after the training (P <0.001 and P <0.001, respectively), without a significant change between immediate post-training and delayed post-training comfort levels (P = 0.19 and P = 0.11, respectively). Residents retained vaginal breech delivery skills taught in simulation 10-26 weeks later, although a decline in skills occurred over this time period. Comfort level was positively affected and retained. These results will aid in determining the frequency of simulation teaching for high-acuity, low-frequency events in a residency simulation curriculum. Copyright © 2018 Society of Obstetricians and Gynaecologists of Canada. Published by Elsevier Inc. All rights reserved.

Experimental analysis of green roof substrate detention characteristics.

PubMed

Yio, Marcus H N; Stovin, Virginia; Werdin, Jörg; Vesuviano, Gianni

2013-01-01

Green roofs may make an important contribution to urban stormwater management. Rainfall-runoff models are required to evaluate green roof responses to specific rainfall inputs. The roof's hydrological response is a function of its configuration, with the substrate - or growing media - providing both retention and detention of rainfall. The objective of the research described here is to quantify the detention effects due to green roof substrates, and to propose a suitable hydrological modelling approach. Laboratory results from experimental detention tests on green roof substrates are presented. It is shown that detention increases with substrate depth and as a result of increasing substrate organic content. Model structures based on reservoir routing are evaluated, and it is found that a one-parameter reservoir routing model coupled with a parameter that describes the delay to start of runoff best fits the observed data. Preliminary findings support the hypothesis that the reservoir routing parameter values can be defined from the substrate's physical characteristics.

Measurement of functional task difficulty during motor learning: What level of difficulty corresponds to the optimal challenge point?

PubMed

Akizuki, Kazunori; Ohashi, Yukari

2015-10-01

The relationship between task difficulty and learning benefit was examined, as was the measurability of task difficulty. Participants were required to learn a postural control task on an unstable surface at one of four different task difficulty levels. Results from the retention test showed an inverted-U relationship between task difficulty during acquisition and motor learning. The second-highest level of task difficulty was the most effective for motor learning, while learning was delayed at the most and least difficult levels. Additionally, the results indicate that salivary α-amylase and the performance dimension of the National Aeronautics and Space Administration-Task Load Index (NASA-TLX) are useful indices of task difficulty. Our findings suggested that instructors may be able to adjust task difficulty based on salivary α-amylase and the performance dimension of the NASA-TLX to enhance learning. Copyright © 2015 Elsevier B.V. All rights reserved.

Infant Long-Term Memory for Associations Formed during Mere Exposure

PubMed Central

Giles, Amy; Rovee-Collier, Carolyn

2011-01-01

We previously found that young infants spontaneously associate stimuli that they merely see together. Using a sensory preconditioning paradigm with 6- and 9-month-olds, we asked how long such associations remain latent before being forgotten and what exposure conditions affect their persistence. Groups were preexposed to two puppets for 1 hr/day for 2 days, 1 hr on 1 day, or 1 hr on 1 day in two sessions; 1 to 27 days later, target actions were modeled on one puppet, and infants were tested with the other puppet 1 day later. The longest delay after which infants imitated the actions on the other puppet defined how long they remembered the association. The data revealed that the preexposure regimen determined retention. Regardless of exposure time, both ages remembered the association longer after two sessions, and younger infants remembered longer than older infants--for 4 weeks--after two 30-min sessions on 1 day. PMID:21474187

Does Bacopa monnieri improve memory performance in older persons? Results of a randomized, placebo-controlled, double-blind trial.

PubMed

Morgan, Annette; Stevens, John

2010-07-01

The objective of this study was to investigate the effectiveness of Bacopa monnieri Linn. for improvement of memory performance in healthy older persons. This was a randomized, double-blind, placebo-controlled trial. The trial took place in Lismore, NSW, Australia between February and July 2005. Ninety-eight (98) healthy participants over 55 years of age were recruited from the general population. Participants were randomized to receive an extract of Bacopa monnieri called BacoMind(TM) (Natural Remedies Pvt. Ltd.), 300 mg/day, or an identical placebo. Following screening, neuropsychologic and subjective memory assessments were performed at baseline and at 12 weeks. Audioverbal and visual memory performance were measured by the Rey Auditory Verbal Learning Test (AVLT), the Rey-Osterrieth Complex Figure Test (CFT), and the Reitan Trail Making Test (TMT). Subjective memory performance was measured by the Memory Complaint Questionnaire (MAC-Q). One hundred and thirty-six (136) subjects volunteered; 103 met entry criteria, 98 commenced, and 81 completed the trial. Bacopa significantly improved verbal learning, memory acquisition, and delayed recall as measured by the AVLT: trial a4 (p = 0.000), trial a5 (p = 0.016); trial a6 (p = 0.000); trial a7 (delayed recall) (p = 0.001); total learning (p = 0.011); and retroactive interference (p = 0.048). CFT, MAC-Q, and TMT scores improved but group differences were not significant. Bacopa versus placebo caused gastrointestinal tract (GIT) side-effects. Bacopa significantly improved memory acquisition and retention in healthy older Australians. This concurs with previous findings and traditional use. Bacopa caused GIT side-effects of increased stool frequency, abdominal cramps, and nausea.

How decentralisation influences the retention of primary health care workers in rural Nigeria.

PubMed

Abimbola, Seye; Olanipekun, Titilope; Igbokwe, Uchenna; Negin, Joel; Jan, Stephen; Martiniuk, Alexandra; Ihebuzor, Nnenna; Aina, Muyi

2015-01-01

In Nigeria, the shortage of health workers is worst at the primary health care (PHC) level, especially in rural communities. And the responsibility for PHC - usually the only form of formal health service available in rural communities - is shared among the three tiers of government (federal, state, and local governments). In addition, the responsibility for community engagement in PHC is delegated to community health committees. This study examines how the decentralisation of health system governance influences retention of health workers in rural communities in Nigeria from the perspective of health managers, health workers, and people living in rural communities. The study adopted a qualitative approach, and data were collected using semi-structured in-depth interviews and focus group discussions. The multi-stakeholder data were analysed for themes related to health system decentralisation. The results showed that decentralisation influences the retention of rural health workers in two ways: 1) The salary of PHC workers is often delayed and irregular as a result of delays in transfer of funds from the national to sub-national governments and because one tier of government can blame failure on another tier of government. Further, the primary responsibility for PHC is often left to the weakest tier of government (local governments). And the result is that rural PHC workers are attracted to working at levels of care where salaries are higher and more regular - in secondary care (run by state governments) and tertiary care (run by the federal government), which are also usually in urban areas. 2) Through community health committees, rural communities influence the retention of health workers by working to increase the uptake of PHC services. Community efforts to retain health workers also include providing social, financial, and accommodation support to health workers. To encourage health workers to stay, communities also take the initiative to co-finance and co-manage PHC services in order to ensure that PHC facilities are functional. In Nigeria and other low- and middle-income countries with decentralised health systems, intervention to increase the retention of health workers in rural communities should seek to reform and strengthen governance mechanisms, using both top-down and bottom-up strategies to improve the remuneration and support for health workers in rural communities.

How decentralisation influences the retention of primary health care workers in rural Nigeria

PubMed Central

Abimbola, Seye; Olanipekun, Titilope; Igbokwe, Uchenna; Negin, Joel; Jan, Stephen; Martiniuk, Alexandra; Ihebuzor, Nnenna; Aina, Muyi

2015-01-01

Background In Nigeria, the shortage of health workers is worst at the primary health care (PHC) level, especially in rural communities. And the responsibility for PHC – usually the only form of formal health service available in rural communities – is shared among the three tiers of government (federal, state, and local governments). In addition, the responsibility for community engagement in PHC is delegated to community health committees. Objective This study examines how the decentralisation of health system governance influences retention of health workers in rural communities in Nigeria from the perspective of health managers, health workers, and people living in rural communities. Design The study adopted a qualitative approach, and data were collected using semi-structured in-depth interviews and focus group discussions. The multi-stakeholder data were analysed for themes related to health system decentralisation. Results The results showed that decentralisation influences the retention of rural health workers in two ways: 1) The salary of PHC workers is often delayed and irregular as a result of delays in transfer of funds from the national to sub-national governments and because one tier of government can blame failure on another tier of government. Further, the primary responsibility for PHC is often left to the weakest tier of government (local governments). And the result is that rural PHC workers are attracted to working at levels of care where salaries are higher and more regular – in secondary care (run by state governments) and tertiary care (run by the federal government), which are also usually in urban areas. 2) Through community health committees, rural communities influence the retention of health workers by working to increase the uptake of PHC services. Community efforts to retain health workers also include providing social, financial, and accommodation support to health workers. To encourage health workers to stay, communities also take the initiative to co-finance and co-manage PHC services in order to ensure that PHC facilities are functional. Conclusions In Nigeria and other low- and middle-income countries with decentralised health systems, intervention to increase the retention of health workers in rural communities should seek to reform and strengthen governance mechanisms, using both top-down and bottom-up strategies to improve the remuneration and support for health workers in rural communities. PMID:25739967

Evaluation of retentive strength of four luting cements with stainless steel crowns in primary molars: An in vitro study

PubMed Central

Parisay, Iman; Khazaei, Yegane

2018-01-01

Background: Stainless steel crown (SSC) is the most reliable restoration for primary teeth with extensive caries. Retention is of great importance for a successful restoration and is provided by various factors such as luting cements. The aim of this study was to evaluate the retentive strength of SSC cemented with four different luting cements. Materials and Methods: In this in vitro study, A total of 55 extracted primary first molars were selected. Following crown selection and cementation (one with no cement and four groups cemented with resin, glass ionomer, zinc phosphate, and polycarboxylate), all the specimens were incubated and thermocycled in 5°C–55°C. Retentive properties of SSCs were tested with a mechanical test machine. First dislodgement of each specimen and full crown removal were recorded. One-way ANOVA test followed by least significant difference test and Kruskal–Wallis test was used for retentive strength comparison at the level of significance of P < 0.05. Results: The results of the study showed that the specimens cemented with zinc phosphate exhibited higher retentive strength as compared to glass ionomer and polycarboxylate (P < 0.001 and P = 0.023, respectively). Conclusion: Zinc phosphate cement showed the most promising results; thus, it can be preferably used for cementation of the teeth with no grossly broken down crowns. PMID:29922339

Moving Knowledge Acquisition From the Lecture Hall to the Student Home: A Prospective Intervention Study.

PubMed

Raupach, Tobias; Grefe, Clemens; Brown, Jamie; Meyer, Katharina; Schuelper, Nikolai; Anders, Sven

2015-09-28

Podcasts are popular with medical students, but the impact of podcast use on learning outcomes in undergraduate medical education has not been studied in detail. Our aim was to assess the impact of podcasts accompanied by quiz questions and lecture attendance on short- and medium-term knowledge retention. Students enrolled for a cardio-respiratory teaching module were asked to prepare for 10 specific lectures by watching podcasts and submitting answers to related quiz questions before attending live lectures. Performance on the same questions was assessed in a surprise test and a retention test. Watching podcasts and submitting answers to quiz questions (versus no podcast/quiz use) was associated with significantly better test performance in all items in the surprise test and 7 items in the retention test. Lecture attendance (versus no attendance) was associated with higher test performance in 3 items and 1 item, respectively. In a linear regression analysis adjusted for age, gender, and overall performance levels, both podcast/quiz use and lecture attendance were significant predictors of student performance. However, the variance explained by podcast/quiz use was greater than the variance explained by lecture attendance in the surprise test (38.7% vs. 2.2%) and retention test (19.1% vs. 4.0%). When used in conjunction with quiz questions, podcasts have the potential to foster knowledge acquisition and retention over and above the effect of live lectures.

Working memory delay period activity marks a domain-unspecific attention mechanism.

PubMed

Katus, Tobias; Müller, Matthias M

2016-03-01

Working memory (WM) recruits neural circuits that also perform perception- and action-related functions. Among the functions that are shared between the domains of WM and perception is selective attention, which supports the maintenance of task-relevant information during the retention delay of WM tasks. The tactile contralateral delay activity (tCDA) component of the event-related potential (ERP) marks the attention-based rehearsal of tactile information in somatosensory brain regions. We tested whether the tCDA reflects the competition for shared attention resources between a WM task and a perceptual task under dual-task conditions. The two tasks were always performed on opposite hands. In different blocks, the WM task had higher or lower priority than the perceptual task. The tCDA's polarity consistently reflected the hand where the currently prioritized task was performed. This suggests that the process indexed by the tCDA is not specific to the domain of WM, but mediated by a domain-unspecific attention mechanism. The analysis of transient ERP components evoked by stimuli in the two tasks further supports the interpretation that the tCDA marks a goal-directed bias in the allocation of selective attention. Larger spatially selective modulations were obtained for stimulus material related to the high-, as compared to low-priority, task. While our results generally indicate functional overlap between the domains of WM and perception, we also found evidence suggesting that selection in internal (mnemonic) and external (perceptual) stimulus representations involves processes that are not active during shifts of preparatory attention. Copyright © 2016 Elsevier Inc. All rights reserved.

Cognitive and functional correlates of accelerated long-term forgetting in temporal lobe epilepsy.

PubMed

Audrain, Samantha; McAndrews, Mary P

2018-03-30

While we know that hippocampal dysfunction is responsible for the memory deficits that patients with temporal lobe epilepsy exhibit at relatively short study-test delays, the role of this region in accelerated long-term forgetting (ALF) is not yet clear. In the present study, we probed the role of the hippocampus in ALF by directly comparing memory for associations to memory that could be supported by item recognition during a forced choice recognition task over delays ranging from 15-min to 72-h. We additionally examined resting-state functional connectivity between the hippocampus and cortical regions known to be involved in processing these types of stimuli, as well as the relationship between ALF and various clinical variables including structural abnormality in the hippocampus, lateralization of epileptic focus, presence of seizures across the retention period, and standardized composite memory scores. We found evidence of accelerated forgetting for item stimuli (but not associative stimuli) by 6 h post-learning, which became statistically reliable by 72-h. This finding suggests that unlike controls, patients were unable to utilize novelty to reject the incorrect object-scene pair. While none of the examined clinical variables were related to long-term forgetting, reduced resting-state functional connectivity between the affected anterior hippocampus and unaffected lateral temporal cortex predicted forgetting of item stimuli over the 72-h delay. Implications for the role of the hippocampus in accelerated long-term forgetting, and existing theories of systems consolidation in this context are discussed. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

The effect of anchovy substrate application to fluor retention rate on Sprague Dawley rat tooth email (in vivo)

NASA Astrophysics Data System (ADS)

Zabrina, S.; Puspitawati, R.; Gunawan, H. A.

2017-08-01

Usage of anchovies (Stolephorus insularis), which contain a high fluoride concentration in a CaF2 compound, needs to be examined as a topical fluoridative agent. Aim: To study the effects of an anchovy substrate application, either by chewing or smearing, in increasing fluoride retention of enamel. Fourteen Sprague Dawley rats were divided into five groups: baseline, experimental (feeding and smearing), and negative controls. After 15 days, lower incisor teeth were extracted and fluoride retention on the enamel surface was measured using EDX. Data were analyzed by the independent samples t-test, the Mann-Whitney U test, and the Kruskal-Wallis test. There was a significant increase in fluoride retention on enamel from the experimental groups compared to the negative control group (p < 0.05). Fluoride retention levels of the experimental feeding group (6.823%) were slightly higher than those of the experimental smearing group (6.783%), though the difference was not statistically significant (p < 0.05). Anchovy substrate application, either by chewing or smearing, increases fluoride retention on tooth enamel.

The Role of Student Characteristics in Predicting Retention in Online Courses

ERIC Educational Resources Information Center

Cochran, Justin D.; Campbell, Stacy M.; Baker, Hope M.; Leeds, Elke M.

2014-01-01

Given the continued issue of student retention for online classes, past research has suggested several "retention strategies" focused on engaging students as a way to reduce their withdrawal rate from these classes. However, a recent study testing the effects of these strategies on retention in online undergraduate business courses…

A Study of Retention Trends of International Students at a Southwestern Public University

ERIC Educational Resources Information Center

Wong Davis, Kristina Marie

2012-01-01

Literature on factors contributing to the retention of international students remained limited. The purpose of this study was to examine the factors related to retention of international undergraduate degree seeking students through conducting pairwise correlational analysis to test the relationship between retention and age, gender, country of…

Factors Associated with Delayed Tuberculosis Test-seeking Behavior in the Peruvian Amazon

PubMed Central

Ford, Carolyn M.; Bayer, Angela M.; Gilman, Robert H.; Onifade, Dami; Acosta, Colleen; Cabrera, Lilia; Vidal, Carlos; Evans, Carlton A.

2010-01-01

This study aimed to determine the psychosocial factors associated with delayed test-seeking among tuberculosis patients. The duration of symptoms before seeking medical care was assessed by interview for 108 newly diagnosed pulmonary tuberculosis patients in the city of Iquitos in the Peruvian Amazon, which has high tuberculosis incidence. Beliefs associated with test-seeking behavior and delay was assessed in these patients. The median delay from symptom onset to seeking diagnostic testing was 61 days (inter-quartile range 30–91 days). The belief that tuberculosis is curable was associated with a 100% longer test-seeking delay; the perception that tuberculosis was common was associated with a 57% longer delay; male gender was associated with a 48% longer delay; and education less than complete secondary schooling was associated with a 44% longer delay. In conclusion, current health promotion activities that emphasize tuberculosis curability and high prevalence may paradoxically increase test-seeking delay and therefore require prospective evaluation. PMID:19996443

Associative learning versus fear habituation as predictors of long-term extinction retention.

PubMed

Brown, Lily A; LeBeau, Richard T; Chat, Ka Yi; Craske, Michelle G

2017-06-01

Violation of unconditioned stimulus (US) expectancy during extinction training may enhance associative learning and result in improved long-term extinction retention compared to within-session habituation. This experiment examines variation in US expectancy (i.e., expectancy violation) as a predictor of long-term extinction retention. It also examines within-session habituation of fear-potentiated startle (electromyography, EMG) and fear of conditioned stimuli (CS) throughout extinction training as predictors of extinction retention. Participants (n = 63) underwent fear conditioning, extinction and retention and provided continuous ratings of US expectancy and EMG, as well as CS fear ratings before and after each phase. Variation in US expectancy throughout extinction and habituation of EMG and fear was entered into a regression as predictors of retention and reinstatement of levels of expectancy and fear. Greater variation in US expectancy throughout extinction training was significantly predictive of enhanced extinction performance measured at retention test, although not after reinstatement test. Slope of EMG and CS fear during extinction did not predict retention of extinction. Within-session habituation of EMG and self-reported fear is not sufficient for long-term retention of extinction learning, and models emphasizing expectation violation may result in enhanced outcomes.

A 24-month, double-blind, placebo-controlled multicentre pilot study of the efficacy and safety of nicergoline 60 mg per day in elderly hypertensive patients with leukoaraiosis.

PubMed

Bès, A; Orgogozo, J M; Poncet, M; Rancurel, G; Weber, M; Bertholom, N; Calvez, R; Stehlé, B

1999-05-01

In this pilot study, 72 non-demented and non-depressive elderly hypertensive patients with evidence of leukoaraiosis on cerebral computed tomography scan (Rezek score: > 16) were randomly assigned to receive either nicergoline 30 mg b.i.d. (n = 36) or a placebo (n = 36) for 24 months. All patients received antihypertensives and their hypertension was controlled under treatment. They were evaluated by nine neuropsychological tests exploring memory, concentration, verbal and motor performances, administered at baseline and at every six-month interval during the study period. At baseline, the two groups were comparable for all demographic and clinical characteristics, including cognitive functions, except for the delayed recall of the Auditory Verbal Learning Test (AVLT), which was better in the placebo group (P = 0.04). Changes in scores over time were compared between the two groups. At the last visit, patients on nicergoline (n = 31) were found to have deteriorated less or to have improved more on test scores than the patients on placebo (n = 30). Significant differences were observed for memory function (AVLT short term recall, P = 0.026; AVLT delayed recall, P = 0.013; and, Benton Visual Retention Test, P = 0.002) and attention and concentration (Letter Cancellation Test, P = 0.043; and, WAIS-R Digit Symbol subtest, P = 0.006). The Rezek score remained unchanged in the two groups. Tolerance of nicergoline was similar to that of placebo. In conclusion, this study shows that nicergoline 30 mg b.i. d. administered over a 24-month period attenuates the deterioration in cognitive functions in elderly hypertensive patients with leukoaraiosis. Whether these effects were specific for this type of white matter changes could not be determined in the context of this pilot study. Copyright 1999 Lippincott Williams & Wilkins

Emotional memory for musical excerpts in young and older adults

PubMed Central

Alonso, Irene; Dellacherie, Delphine; Samson, Séverine

2015-01-01

The emotions evoked by music can enhance recognition of excerpts. It has been suggested that memory is better for high than for low arousing music (Eschrich et al., 2005; Samson et al., 2009), but it remains unclear whether positively (Eschrich et al., 2008) or negatively valenced music (Aubé et al., 2013; Vieillard and Gilet, 2013) may be better recognized. Moreover, we still know very little about the influence of age on emotional memory for music. To address these issues, we tested emotional memory for music in young and older adults using musical excerpts varying in terms of arousal and valence. Participants completed immediate and 24 h delayed recognition tests. We predicted highly arousing excerpts to be better recognized by both groups in immediate recognition. We hypothesized that arousal may compensate consolidation deficits in aging, thus showing more prominent benefit of high over low arousing stimuli in older than younger adults on delayed recognition. We also hypothesized worst retention of negative excerpts for the older group, resulting in a recognition benefit for positive over negative excerpts specific to older adults. Our results suggest that although older adults had worse recognition than young adults overall, effects of emotion on memory do not seem to be modified by aging. Results on immediate recognition suggest that recognition of low arousing excerpts can be affected by valence, with better memory for positive relative to negative low arousing music. However, 24 h delayed recognition results demonstrate effects of emotion on memory consolidation regardless of age, with a recognition benefit for high arousal and for negatively valenced music. The present study highlights the role of emotion on memory consolidation. Findings are examined in light of the literature on emotional memory for music and for other stimuli. We finally discuss the implication of the present results for potential music interventions in aging and dementia. PMID:25814950

The impact of anticipated HIV stigma on delays in HIV testing behaviors: findings from a community-based sample of men who have sex with men and transgender women in New York City.

PubMed

Golub, Sarit A; Gamarel, Kristi E

2013-11-01

Treatment as prevention (TaSP) is a critical component of biomedical interventions to prevent HIV transmission. However, its success is predicated on testing and identifying undiagnosed individuals to ensure linkage and retention in HIV care. Research has examined the impact of HIV-associated stigma on HIV-positive individuals, but little work has explored how anticipated HIV stigma-the expectation of rejection or discrimination against by others in the event of seroconversion-may serve as a barrier to HIV testing behaviors. This study examined the association between anticipated stigma and HIV testing behaviors among a sample of 305 men who have sex with men (MSM) and transgender women living in New York City. Participants' mean age was 33.0; 65.5% were racial/ethnic minority; and 50.2% earned <$20,000 per year. Overall, 32% of participants had not had an HIV test in the past 6 months. Anticipated stigma was negatively associated with risk perception. In multivariate models, anticipated stigma, risk perception, and younger age were significant predictors of HIV testing behaviors. Anti-HIV stigma campaigns targeting HIV-negative individuals may have the potential to significantly impact social norms around HIV testing and other biomedical strategies, such pre-exposure prophylaxis, at a critical moment for the redefinition of HIV prevention.

Similarities and Differences Between Working Memory and Long-Term Memory: Evidence From the Levels-of-Processing Span Task

PubMed Central

Rose, Nathan S.; Myerson, Joel; Roediger, Henry L.; Hale, Sandra

2010-01-01

Two experiments compared the effects of depth of processing on working memory (WM) and long-term memory (LTM) using a levels-of-processing (LOP) span task, a newly developed WM span procedure that involves processing to-be-remembered words based on their visual, phonological, or semantic characteristics. Depth of processing had minimal effect on WM tests, yet subsequent memory for the same items on delayed tests showed the typical benefits of semantic processing. Although the difference in LOP effects demonstrates a dissociation between WM and LTM, we also found that the retrieval practice provided by recalling words on the WM task benefited long-term retention, especially for words initially recalled from supraspan lists. The latter result is consistent with the hypothesis that WM span tasks involve retrieval from secondary memory, but the LOP dissociation suggests the processes engaged by WM and LTM tests may differ. Therefore, similarities and differences between WM and LTM depend on the extent to which retrieval from secondary memory is involved and whether there is a match (or mismatch) between initial processing and subsequent retrieval, consistent with transfer-appropriate-processing theory. PMID:20192543

Third graders' understanding of core political concepts (law, nation-state, government) before and after teaching.

PubMed

Berti, A E; Andriolo, A

2001-11-01

A curriculum of about 22 hr distributed over 3 months on some core political notions (law, the main Italian political offices, the state) was implemented in an Italian 3rd-grade class of 23 children. Another class of 20 children formed the comparison group. The workings of the executive system were exemplified by explaining the running of the school (which in Italy is state-run). Children's learning and retention of these notions were tested twice, 1 month and 10 months after the end of the curriculum. At pre-test, before implementation of the curriculum, the majority of the children did not have a concept of the political domain: They did not know of parliament and government, hardly distinguished between the law and other types of rules, and did not know that teachers, policemen, and judges are public servants. At post- and delayed post-test, most of the children in the experimental group had mastered the concepts, performing significantly better than the comparison group. Thus, the development of political understanding appears to be due to the acquisition of relevant domain-specific knowledge rather than the emergence of across-the-board logic ability.

Magnifying visual target information and the role of eye movements in motor sequence learning.

PubMed

Massing, Matthias; Blandin, Yannick; Panzer, Stefan

2016-01-01

An experiment investigated the influence of eye movements on learning a simple motor sequence task when the visual display was magnified. The task was to reproduce a 1300 ms spatial-temporal pattern of elbow flexions and extensions. The spatial-temporal pattern was displayed in front of the participants. Participants were randomly assigned to four groups differing on eye movements (free to use their eyes/instructed to fixate) and the visual display (small/magnified). All participants had to perform a pre-test, an acquisition phase, a delayed retention test, and a transfer test. The results indicated that participants in each practice condition increased their performance during acquisition. The participants who were permitted to use their eyes in the magnified visual display outperformed those who were instructed to fixate on the magnified visual display. When a small visual display was used, the instruction to fixate induced no performance decrements compared to participants who were permitted to use their eyes during acquisition. The findings demonstrated that a spatial-temporal pattern can be learned without eye movements, but being permitting to use eye movements facilitates the response production when the visual angle is increased. Copyright © 2015 Elsevier B.V. All rights reserved.

The First Slow Step: Differential Effects of Object and Word-Form Familiarization on Retention of Fast-Mapped Words

ERIC Educational Resources Information Center

Kucker, Sarah C.; Samuelson, Larissa K.

2012-01-01

Recent research demonstrated that although 24-month-old infants do well on the initial pairing of a novel word and novel object in fast-mapping tasks, they are unable to retain the mapping after a 5 min delay. The current study examines the role of familiarity with the objects and words on infants' ability to bridge between the initial fast…

Test-Enhanced E-Learning Strategies in Postgraduate Medical Education: A Randomized Cohort Study.

PubMed

DelSignore, Lisa A; Wolbrink, Traci A; Zurakowski, David; Burns, Jeffrey P

2016-11-21

The optimal design of pedagogical strategies for e-learning in graduate and postgraduate medical education remains to be determined. Video-based e-learning use is increasing, with initial research suggesting that taking short breaks while watching videos (independent of answering test questions) may improve learning by focusing attention on the content presented. Interspersed test questions may also improve knowledge acquisition and retention. To examine the effect of interspersed test questions and periodic breaks on immediate knowledge acquisition and retention at 6 months by pediatric residents engaged in video-based e-learning. First- and second-year pediatric residents were randomized to 1 of the following 3 groups: viewing the complete video uninterrupted (full video), viewing the video interrupted with unrelated logic puzzles (logic puzzles), or viewing the video interrupted with brief comprehension test questions (short answer questions). Residents answered pre- and post-tests before and after video viewing, followed by a retention test at 6 months. Primary outcome included comparison of the change in test scores between groups. A total of 49 residents completed the initial testing session. All 3 learning groups had comparable mean increases in immediate knowledge gain, but with no significant differences between groups (F 2,46 =0.35, P=.71). Thirty-five residents completed retention testing with comparable degrees of knowledge retention in the full video and short answer test questions groups (P<.001), but no significant change in the logic puzzles group (F 1,32 =2.44, P=.13). Improved knowledge gain was not demonstrated among residents answering interspersed questions or completing logic puzzles during interrupted online video viewing when compared with residents viewing uninterrupted video content. However, residents who either participated in uninterrupted video viewing or answered interspersed questions during interrupted video viewing demonstrated significant knowledge retention at 6 months. ©Lisa A DelSignore, Traci A Wolbrink, David Zurakowski, Jeffrey P Burns. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 21.11.2016.

The contributions of encoding, retention, and recall to the Hebb effect.

PubMed

Oberauer, Klaus; Meyer, Nadine

2009-10-01

The article reports an experiment testing whether the Hebb repetition effect-the gradual improvement of immediate serial recall when the same list is repeated several times-depends on overt recall of the repeated lists. Previous reports which suggest that recall is critical confound the recall manipulation with retention interval. The present experiment orthogonally varies retention interval (0 or 9 s) and whether the list is to be recalled after the retention interval. Hebb repetition learning is assessed in a final test phase. A repetition effect was obtained in all four experimental conditions; it was larger for recalled than non-recalled lists, whereas retention interval had no effect. The results show that encoding is sufficient to generate cumulative long-term learning, which is strengthened by recall. Rehearsal, if it takes place in the retention interval at all, does not have the same effect on long-term learning as overt recall.

Cross-Modal Decoding of Neural Patterns Associated with Working Memory: Evidence for Attention-Based Accounts of Working Memory.

PubMed

Majerus, Steve; Cowan, Nelson; Péters, Frédéric; Van Calster, Laurens; Phillips, Christophe; Schrouff, Jessica

2016-01-01

Recent studies suggest common neural substrates involved in verbal and visual working memory (WM), interpreted as reflecting shared attention-based, short-term retention mechanisms. We used a machine-learning approach to determine more directly the extent to which common neural patterns characterize retention in verbal WM and visual WM. Verbal WM was assessed via a standard delayed probe recognition task for letter sequences of variable length. Visual WM was assessed via a visual array WM task involving the maintenance of variable amounts of visual information in the focus of attention. We trained a classifier to distinguish neural activation patterns associated with high- and low-visual WM load and tested the ability of this classifier to predict verbal WM load (high-low) from their associated neural activation patterns, and vice versa. We observed significant between-task prediction of load effects during WM maintenance, in posterior parietal and superior frontal regions of the dorsal attention network; in contrast, between-task prediction in sensory processing cortices was restricted to the encoding stage. Furthermore, between-task prediction of load effects was strongest in those participants presenting the highest capacity for the visual WM task. This study provides novel evidence for common, attention-based neural patterns supporting verbal and visual WM. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Resting state EEG correlates of memory consolidation.

PubMed

Brokaw, Kate; Tishler, Ward; Manceor, Stephanie; Hamilton, Kelly; Gaulden, Andrew; Parr, Elaine; Wamsley, Erin J

2016-04-01

Numerous studies demonstrate that post-training sleep benefits human memory. At the same time, emerging data suggest that other resting states may similarly facilitate consolidation. In order to identify the conditions under which non-sleep resting states benefit memory, we conducted an EEG (electroencephalographic) study of verbal memory retention across 15min of eyes-closed rest. Participants (n=26) listened to a short story and then either rested with their eyes closed, or else completed a distractor task for 15min. A delayed recall test was administered immediately following the rest period. We found, first, that quiet rest enhanced memory for the short story. Improved memory was associated with a particular EEG signature of increased slow oscillatory activity (<1Hz), in concert with reduced alpha (8-12Hz) activity. Mindwandering during the retention interval was also associated with improved memory. These observations suggest that a short period of quiet rest can facilitate memory, and that this may occur via an active process of consolidation supported by slow oscillatory EEG activity and characterized by decreased attention to the external environment. Slow oscillatory EEG rhythms are proposed to facilitate memory consolidation during sleep by promoting hippocampal-cortical communication. Our findings suggest that EEG slow oscillations could play a significant role in memory consolidation during other resting states as well. Copyright © 2016 Elsevier Inc. All rights reserved.

Relative Ease in Creating Detailed Orthographic Representations Contrasted with Severe Difficulties to Maintain Them in Long-term Memory Among Dyslexic Children.

PubMed

Binamé, Florence; Danzio, Sophie; Poncelet, Martine

2015-11-01

Most research into orthographic learning abilities has been conducted in English with typically developing children using reading-based tasks. In the present study, we examined the abilities of French-speaking children with dyslexia to create novel orthographic representations for subsequent use in spelling and to maintain them in long-term memory. Their performance was compared with that of chronological age (CA)-matched and reading age (RA)-matched control children. We used an experimental task designed to provide optimal learning conditions (i.e. 10 spelling practice trials) ensuring the short-term acquisition of the spelling of the target orthographic word forms. After a 1-week delay, the long-term retention of the targets was assessed by a spelling post-test. Analysis of the results revealed that, in the short term, children with dyslexia learned the novel orthographic word forms well, only differing from both CA and RA controls on the initial decoding of the targets and from CA controls on the first two practice trials. In contrast, a dramatic drop was observed in their long-term retention relative to CA and RA controls. These results support the suggestion of the self-teaching hypothesis (Share, 1995) that initial errors in the decoding and spelling of unfamiliar words may hinder the establishment of fully specified novel orthographic representations. Copyright © 2015 John Wiley & Sons, Ltd.

When Does Testing Enhance Retention? A Distribution-Based Interpretation of Retrieval as a Memory Modifier

ERIC Educational Resources Information Center

Halamish, Vered; Bjork, Robert A.

2011-01-01

Tests, as learning events, can enhance subsequent recall more than do additional study opportunities, even without feedback. Such advantages of testing tend to appear, however, only at long retention intervals and/or when criterion tests stress recall, rather than recognition, processes. We propose that the interaction of the benefits of testing…

76 FR 28131 - Federal Motor Vehicle Safety Standards; Motorcycle Helmets

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-13

..., this final rule sets a quasi-static load application rate for the helmet retention system; revises the... Analysis and Conclusion e. Quasi-Static Retention Test f. Helmet Conditioning Tolerances g. Other... it as a quasi-static test, instead of a static test. Specifying the application rate will aid...

Testing during Study Insulates against the Buildup of Proactive Interference

ERIC Educational Resources Information Center

Szpunar, Karl K.; McDermott, Kathleen B.; Roediger, Henry L., III

2008-01-01

Recent interest in the benefits of retrieval practice on long-term retention--the testing effect--has spawned a considerable amount of research toward understanding the underlying nature of this ubiquitous memory phenomenon. Taking a test may benefit retention through both direct means (engaging appropriate retrieval processes) and indirect means…

In vivo traffic of indium-111-oxine labeled human lymphocytes collected by automated apheresis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Read, E.J.; Keenan, A.M.; Carter, C.S.

1990-06-01

The in vivo traffic patterns of autologous lymphocytes were studied in five normal human volunteers using lymphocytes obtained by automated apheresis, separated on Ficoll-Hypaque gradients, and labeled ex vivo with {sup 111}In-oxine. Final lymphocyte infusions contained 1.8-3.1 X 10(9) cells and 270-390 microCi (9.99-14.43 MBq) {sup 111}In, or 11-17 microCi (0.41-0.63 MBq) per 10(8) lymphocytes. Gamma imaging showed transient lung uptake and significant retention of radioactivity in the liver and spleen. Progressive uptake of activity in normal, nonpalpable axillary and inguinal lymph nodes was seen from 24 to 96 hr. Accumulation of radioactivity also was demonstrated at the forearm skinmore » test site, as well as in its associated epitrochlear and axillary lymph nodes, in a subject who had been tested for delayed hypersensitivity with tetanus toxoid. Indium-111-oxine labeled human lymphocytes may provide a useful tool for future studies of normal and abnormal lymphocyte traffic.« less

Early diagnosis and treatment in a child with foodborne botulism.

PubMed

Proverbio, Maria Renata; Lamba, Marta; Rossi, Alessandro; Siani, Paolo

2016-06-01

Foodborne botulism is a neuroparalytic disease caused by ingestion of food contaminated with botulinum toxins. Despite rare the mortality rate is high if untreated. Diagnosis of botulism is still a challenge for clinician, due to the variability of clinical manifestations and disease course. We report on a child with type B botulin intoxication who was early diagnosed and treated underlining that clinical suspicion is crucial to start prompt treatment. An 11-year-old boy presented with bilateral ptosis and mydriasis, dry mouth, difficulty in swallowing, dysphonia, urine retention and constipation. Clear sensorium and no fever were observed. Immediately the suspicion of botulism was risen and botulinum antitoxin was administered. 3 days later serum and rectal samples tested positive for Clostridium botulinum. The patient completely recovered when discharged from hospital. Foodborne botulism is still possible in developed countries. The confirmation test of botulism requires some days. To avoid long delays between intoxication and diagnosis prompt clinical suspicion is thus crucial. The outcome depends on rapid implementation of appropriate management with intensive respiratory care and antitoxin administration. Copyright © 2015 Elsevier Ltd. All rights reserved.

Retention in medication-assisted treatment programs in Ukraine-Identifying factors contributing to a continuing HIV epidemic.

PubMed

Dumchev, Kostyantyn; Dvoryak, Sergii; Chernova, Olena; Morozova, Olga; Altice, Frederick L

2017-10-01

Opioid agonist treatments (OAT) are widely-used, evidence-based strategies for treating opioid dependence and reducing HIV transmission. The positive benefits of OAT are strongly correlated with time spent in treatment, making retention a key indicator for program quality. This study assessed patient retention and associated factors in Ukraine, where OAT was first introduced in 2004. Data from clinical records of 2916 patients enrolled in OAT at thirteen sites from 2005 to 2012 were entered into an electronic monitoring system. Survival analysis methods were used to determine the probability of retention and its correlates. Twelve-month retention was 65.8%, improving from 27.7% in 2005, to 70.9% in 2011. In multivariable analyses, the correlates of retention were receiving medium and high doses of medication (compared to low doses, dropout aHR=0.57 for both medium and high doses), having not been tested for HIV and tuberculosis (compared to not being tested, dropout aHR=4.44 and 3.34, respectively), and among those who were tested-a negative TB test result (compared to receiving a positive test result, dropout aHR=0.67). Retention in Ukrainian OAT programs, especially in recent years, is comparable to other countries. The results confirm the importance of adequate OAT dosing (≥60mg of methadone, ≥8mg of buprenorphine). Higher dosing, however, will require interventions that address negative attitudes toward OAT by patients and providers. Interruption of OAT, in the case developing tuberculosis, should incorporate continuity of OAT for TB patients through integrated care delivery systems. Copyright © 2017 Elsevier B.V. All rights reserved.

3D CPR Game Can Improve CPR Skill Retention.

PubMed

Li, Jia; Xu, Yimin; Xu, Yahong; Yue, Peng; Sun, Liu; Guo, Ming; Xiao, Shuqin; Ding, Shu; Cui, Yanyan; Li, Shulan; Yang, Qiuying; Chang, Polun; Wu, Ying

2015-01-01

Adequate cardiopulmonary resuscitation (CPR) skill is essential in improving survival rate of sudden cardiac arrest (SCA). However, the skill deteriorates rapidly following CPR training. We developed a computer game by using 3-Dimensional virtual technology (3-D CPR game) for laypersons in the purpose to improve skill retention. As the testing phase, a randomized control trial, in which we recruited 97 freshman medical students who had no prior CPR training experience, was used to test its effect on 3-month CPR Skill retention. The usability of the game was also tested using a 33 item questionnaire rated with 5-point Likert scale. Three months after the initial CPR training, the retention rate of CPR skill in the game group was significantly higher compared with the control (p<0.05) and the average score on 4 dimensions of usability were 3.99-4.05. Overall, using 3-D CPR game in improving CPR skill retention is feasible and effective.

Short-term memory for event duration: modality specificity and goal dependency.

PubMed

Takahashi, Kohske; Watanabe, Katsumi

2012-11-01

Time perception is involved in various cognitive functions. This study investigated the characteristics of short-term memory for event duration by examining how the length of the retention period affects inter- and intramodal duration judgment. On each trial, a sample stimulus was followed by a comparison stimulus, after a variable delay period (0.5-5 s). The sample and comparison stimuli were presented in the visual or auditory modality. The participants determined whether the comparison stimulus was longer or shorter than the sample stimulus. The distortion pattern of subjective duration during the delay period depended on the sensory modality of the comparison stimulus but was not affected by that of the sample stimulus. When the comparison stimulus was visually presented, the retained duration of the sample stimulus was shortened as the delay period increased. Contrarily, when the comparison stimulus was presented in the auditory modality, the delay period had little to no effect on the retained duration. Furthermore, whenever the participants did not know the sensory modality of the comparison stimulus beforehand, the effect of the delay period disappeared. These results suggest that the memory process for event duration is specific to sensory modality and that its performance is determined depending on the sensory modality in which the retained duration will be used subsequently.

Moving Knowledge Acquisition From the Lecture Hall to the Student Home: A Prospective Intervention Study

PubMed Central

Grefe, Clemens; Brown, Jamie; Meyer, Katharina; Schuelper, Nikolai; Anders, Sven

2015-01-01

Background Podcasts are popular with medical students, but the impact of podcast use on learning outcomes in undergraduate medical education has not been studied in detail. Objective Our aim was to assess the impact of podcasts accompanied by quiz questions and lecture attendance on short- and medium-term knowledge retention. Methods Students enrolled for a cardio-respiratory teaching module were asked to prepare for 10 specific lectures by watching podcasts and submitting answers to related quiz questions before attending live lectures. Performance on the same questions was assessed in a surprise test and a retention test. Results Watching podcasts and submitting answers to quiz questions (versus no podcast/quiz use) was associated with significantly better test performance in all items in the surprise test and 7 items in the retention test. Lecture attendance (versus no attendance) was associated with higher test performance in 3 items and 1 item, respectively. In a linear regression analysis adjusted for age, gender, and overall performance levels, both podcast/quiz use and lecture attendance were significant predictors of student performance. However, the variance explained by podcast/quiz use was greater than the variance explained by lecture attendance in the surprise test (38.7% vs 2.2%) and retention test (19.1% vs 4.0%). Conclusions When used in conjunction with quiz questions, podcasts have the potential to foster knowledge acquisition and retention over and above the effect of live lectures. PMID:26416467

The effects of exposure to dynamic expressions of affect on 5-month-olds' memory.

PubMed

Flom, Ross; Janis, Rebecca B; Garcia, Darren J; Kirwan, C Brock

2014-11-01

The purpose of this study was to examine the behavioral effects of adults' communicated affect on 5-month-olds' visual recognition memory. Five-month-olds were exposed to a dynamic and bimodal happy, angry, or neutral affective (face-voice) expression while familiarized to a novel geometric image. After familiarization to the geometric image and exposure to the affective expression, 5-month-olds received either a 5-min or 1-day retention interval. Following the 5-min retention interval, infants exposed to the happy affective expressions showed a reliable preference for a novel geometric image compared to the recently familiarized image. Infants exposed to the neutral or angry affective expression failed to show a reliable preference following a 5-min delay. Following the 1-day retention interval, however, infants exposed to the neutral expression showed a reliable preference for the novel geometric image. These results are the first to demonstrate that 5-month-olds' visual recognition memory is affected by the presentation of affective information at the time of encoding. Copyright © 2014 Elsevier Inc. All rights reserved.

Decoding attended information in short-term memory: an EEG study.

PubMed

LaRocque, Joshua J; Lewis-Peacock, Jarrod A; Drysdale, Andrew T; Oberauer, Klaus; Postle, Bradley R

2013-01-01

For decades it has been assumed that sustained, elevated neural activity--the so-called active trace--is the neural correlate of the short-term retention of information. However, a recent fMRI study has suggested that this activity may be more related to attention than to retention. Specifically, a multivariate pattern analysis failed to find evidence that information that was outside the focus of attention, but nonetheless in STM, was retained in an active state. Here, we replicate and extend this finding by querying the neural signatures of attended versus unattended information within STM with electroencephalograpy (EEG), a method sensitive to oscillatory neural activity to which the previous fMRI study was insensitive. We demonstrate that in the delay-period EEG activity, there is information only about memory items that are also in the focus of attention. Information about items outside the focus of attention is not detectable. This result converges with the fMRI findings to suggest that, contrary to conventional wisdom, an active memory trace may be unnecessary for the short-term retention of information.

Extinction and spontaneous recovery of spatial behavior in pigeons.

PubMed

Leising, Kenneth J; Wong, Jared; Blaisdell, Aaron P

2015-10-01

We investigated extinction and spontaneous recovery of spatial associations using a landmark-based appetitive search task in a touchscreen preparation with pigeons. Four visual landmarks (A, B, C, and D) were separately established as signals of a hidden reinforced target among an 8 × 7 array of potential target locations. The target was located above landmarks (LM) A and C and below B and D. After conditioning, A and B were extinguished. Responding to A and C was assessed on probe tests 2 days following extinction, whereas, B and D were tested 14 days after extinction. We observed spontaneous recovery from spatial extinction following a 14-day, but not a 2-day, postextinction retention interval. Furthermore, by plotting the spatial distribution of responding across the X and Y axes during testing, we found that spontaneous recovery of responding to the target in our task was due to enhanced spatial control (i.e., a change in the overall distribution of responses) following the long delay to testing. These results add spatial extinction and spontaneous recovery to the list of findings supporting the assertion that extinction involves new learning that attenuates the originally acquired response, and that original learning of the spatial relationship between paired events survives extinction. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

The Influence of Retrieval Practice on Memory and Comprehension of Science Texts

ERIC Educational Resources Information Center

Hinze, Scott R.

2010-01-01

The testing effect, where retrieval practice aids performance on later tests, may be a powerful tool for improving learning and retention. Three experiments test the potentials and limitations of retrieval practice for retention and comprehension of the content of science texts. Experiment 1 demonstrated that cued recall of paragraphs, but not…

Retention and wear behaviors of two implant overdenture stud-type attachments at different implant angulations.

PubMed

Choi, Jae-Won; Bae, Ji-Hyeon; Jeong, Chang-Mo; Huh, Jung-Bo

2017-05-01

Implant angulation should be considered when selecting an attachment. Some in vitro studies have investigated the relationship between implant angulation and changes in the retention force of the stud attachment, but few studies have evaluated the effect of cyclic loading and repeated cycles of insertion and removal on the stud attachment. The purpose of this in vitro study was to evaluate the effects of implant angulation on the retentive characteristics of overdentures with 2 different stud attachments, an experimental system and O-rings in red and orange, after cyclic loading and repeated insertion and removal cycles. The canine region of a mandibular experimental model was fitted with 2 implant fixtures with 2 different stud attachment systems at implant angulations of 0, 15, or 30 degrees. A mastication simulator was used to simulate cyclic loading, and a universal testing machine was used to evaluate retentive force changes after repeated insertion and removal cycles. To simulate the numbers of mastication and insertion and removal cycles per annum, 400000 cyclic loadings and 1080 insertion and removal cycles were performed. Wear patterns and attachment surface deformations were evaluated by scanning electron microscopy. Data were analyzed using the Kruskal-Wallis test, Mann-Whitney U test with Bonferroni correction (α=.05/3=.017), and the paired-sample Student t test (α=.05). When retentive forces before and after testing were compared, O-ring showed significant retention loss at all implant angulations (P<.001). In contrast, the experimental system showed little retention loss in the 0- and 15-degree models (P>.05), whereas the 30-degree model showed a significant increase in retentive force (P=.001). At all implant angulations, retention loss increased significantly for the orange O-ring, followed by the red O-ring, and the experimental system (P<.001). Scanning electron microscopy analysis showed more intense wear in the matrix than the patrix (abutment that matches to matrix) and more severe wear and deformation of the O-ring rubber matrix than of the experimental zirconia ball. Upon completion of the experiment, wear and deformation were found for all attachment systems. Even when implants are not installed in parallel, the experimental system can be used without involving great loss of retention. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Retention Strength of Conical Welding Caps for Fixed Implant-Supported Prostheses.

PubMed

Nardi, Diego; Degidi, Marco; Sighinolfi, Gianluca; Tebbel, Florian; Marchetti, Claudio

This study evaluated the retention strength of welding caps for Ankylos standard abutments using a pull-out test. Each sample consisted of an implant abutment and its welding cap. The tests were performed with a Zwick Roell testing machine with a 1-kN load cell. The retention strength of the welding caps increased with higher abutment diameters and higher head heights and was comparable or superior to the values reported in the literature for the temporary cements used in implant dentistry. Welding caps provide a reliable connection between an abutment and a fixed prosthesis without the use of cement.

Transdermal Scopolamine and Acute Postoperative Urinary Retention in Pelvic Reconstructive Surgery.

PubMed

Propst, Katie; OʼSullivan, David M; Tulikangas, Paul K

2016-01-01

To evaluate the relationship between perioperative use of transdermal scopolamine and the rate of urinary retention after stress urinary incontinence and pelvic organ prolapse procedures in women. This is a retrospective, cohort study; the primary outcome is the rate of acute postoperative urinary retention. Study candidates were adult female patients who underwent pelvic reconstructive surgery at a tertiary care center. Subjects were excluded if preoperative postvoid residual urine volume was greater than 150 mL, preoperative urodynamic testing was not performed, or if a postoperative trial of void was not performed. Subjects were grouped based on preoperative use of transdermal scopolamine. Patients were selected consecutively until 138 subjects per group was reached. Differences in rates of acute postoperative urinary retention were evaluated using a chi-square test. Group demographics were evaluated using t tests and χ tests. Two hundred seventy-six subjects were included in the analysis, 138 received a transdermal scopolamine patch in the perioperative period and 138 did not. The overall rate of acute postoperative urinary retention was 25.3%. There was no significant difference in the rate of acute postoperative urinary retention between the study groups (scopolamine, 26.8%; no scopolamine, 23.9%; P = 0.580). Demographics of the 2 groups were compared; patients who received scopolamine patch were younger (P = 0.001), received a greater amount of intravenous fluids (P = 0.007), and underwent a greater percentage of incontinence procedures (P = 0.048). Otherwise, there were no differences between the groups. Transdermal scopolamine is not a risk factor for acute postoperative urinary retention after pelvic reconstructive procedures.

NMDA Receptor-Dependent Processes in the Medial Prefrontal Cortex Are Important for Acquisition and the Early Stage of Consolidation during Trace, but Not Delay Eyeblink Conditioning

ERIC Educational Resources Information Center

Takehara-Nishiuchi, Kaori; Kawahara, Shigenori; Kirino, Yutaka

2005-01-01

Permanent lesions in the medial prefrontal cortex (mPFC) affect acquisition of conditioned responses (CRs) during trace eyeblink conditioning and retention of remotely acquired CRs. To clarify further roles of the mPFC in this type of learning, we investigated the participation of the mPFC in mnemonic processes both during and after daily…

Mechanisms of tissue uptake and retention of paclitaxel-coated balloons: impact on neointimal proliferation and healing.

PubMed

Granada, Juan F; Stenoien, Mark; Buszman, Piotr P; Tellez, Armando; Langanki, Dan; Kaluza, Greg L; Leon, Martin B; Gray, William; Jaff, Michael R; Schwartz, Robert S

2014-01-01

The efficacy of paclitaxel-coated balloons (PCB) for restenosis prevention has been demonstrated in humans. However, the mechanism of action for sustained drug retention and biological efficacy following single-time drug delivery is still unknown. The pharmacokinetic profile and differences in drug concentration (vessel surface vs arterial wall) of two different paclitaxel coating formulations (3 µg/mm(2)) displaying opposite solubility characteristics (CC=crystalline vs AC=amorphous) were tested in vivo and compared with paclitaxel-eluting stents (PES). Also, the biological effect of both PCB formulations on vascular healing was tested in the porcine coronary injury model. One hour following balloon inflation, both formulations achieved similar arterial paclitaxel levels (CC=310 vs AC=245 ng/mg; p=NS). At 24 h, the CC maintained similar tissue concentrations, whereas the AC tissue levels declined by 99% (p<0.01). At this time point, arterial levels were 20-fold (CC) and 5-fold (AC) times higher compared to the PES group (p<0.05). At 28 days, arterial levels retained were 9.2% (CC) and 0.04% (AC, p<0.01) of the baseline levels. Paclitaxel concentration on the vessel surface was higher in the CC at 1 (CC=36.7% vs AC=13.1%, p<0.05) and 7 days (CC=38.4% vs AC=11%, p<0.05). In addition, the CC induced higher levels of neointimal inhibition, fibrin deposition and delayed healing compared with the AC group. The presence of paclitaxel deposits on the vessel surface driving diffusion into the arterial tissue in a time-dependent fashion supports the mechanism of action of PCB. This specific pharmacokinetic behaviour influences the patterns of neointimal formation and healing.

Mechanisms of tissue uptake and retention of paclitaxel-coated balloons: impact on neointimal proliferation and healing

PubMed Central

Granada, Juan F; Stenoien, Mark; Buszman, Piotr P; Tellez, Armando; Langanki, Dan; Kaluza, Greg L; Leon, Martin B; Gray, William; Jaff, Michael R; Schwartz, Robert S

2014-01-01

Background The efficacy of paclitaxel-coated balloons (PCB) for restenosis prevention has been demonstrated in humans. However, the mechanism of action for sustained drug retention and biological efficacy following single-time drug delivery is still unknown. Methods and results The pharmacokinetic profile and differences in drug concentration (vessel surface vs arterial wall) of two different paclitaxel coating formulations (3 µg/mm2) displaying opposite solubility characteristics (CC=crystalline vs AC=amorphous) were tested in vivo and compared with paclitaxel-eluting stents (PES). Also, the biological effect of both PCB formulations on vascular healing was tested in the porcine coronary injury model. One hour following balloon inflation, both formulations achieved similar arterial paclitaxel levels (CC=310 vs AC=245 ng/mg; p=NS). At 24 h, the CC maintained similar tissue concentrations, whereas the AC tissue levels declined by 99% (p<0.01). At this time point, arterial levels were 20-fold (CC) and 5-fold (AC) times higher compared to the PES group (p<0.05). At 28 days, arterial levels retained were 9.2% (CC) and 0.04% (AC, p<0.01) of the baseline levels. Paclitaxel concentration on the vessel surface was higher in the CC at 1 (CC=36.7% vs AC=13.1%, p<0.05) and 7 days (CC=38.4% vs AC=11%, p<0.05). In addition, the CC induced higher levels of neointimal inhibition, fibrin deposition and delayed healing compared with the AC group. Conclusions The presence of paclitaxel deposits on the vessel surface driving diffusion into the arterial tissue in a time-dependent fashion supports the mechanism of action of PCB. This specific pharmacokinetic behaviour influences the patterns of neointimal formation and healing. PMID:25332821

Nanoparticulated docetaxel exerts enhanced anticancer efficacy and overcomes existing limitations of traditional drugs.

PubMed

Choi, Jinhyang; Ko, Eunjung; Chung, Hye-Kyung; Lee, Jae Hee; Ju, Eun Jin; Lim, Hyun Kyung; Park, Intae; Kim, Kab-Sig; Lee, Joo-Hwan; Son, Woo-Chan; Lee, Jung Shin; Jung, Joohee; Jeong, Seong-Yun; Song, Si Yeol; Choi, Eun Kyung

2015-01-01

Nanoparticulation of insoluble drugs improves dissolution rate, resulting in increased bioavailability that leads to increased stability, better efficacy, and reduced toxicity of drugs. Docetaxel (DTX), under the trade name Taxotere™, is one of the representative anticancer chemotherapeutic agents of this era. However, this highly lipophilic and insoluble drug has many adverse effects. Our novel and widely applicable nanoparticulation using fat and supercritical fluid (NUFS™) technology enabled successful nanoscale particulation of DTX (Nufs-DTX). Nufs-DTX showed enhanced dissolution rate and increased aqueous stability in water. After confirming the preserved mechanism of action of DTX, which targets microtubules, we showed that Nufs-DTX exhibited similar effects in proliferation and clonogenic assays using A549 cells. Interestingly, we observed that Nufs-DTX had a greater in vivo tumor growth delay effect on an A549 xenograft model than Taxotere™, which was in agreement with the improved drug accumulation in tumors according to the biodistribution result, and was caused by the enhanced permeability and retention (EPR) effect. Although both Nufs-DTX and Taxotere™ showed negative results for our administration dose in the hematologic toxicity test, Nufs-DTX showed much less toxicity than Taxotere™ in edema, paralysis, and paw-withdrawal latency on a hot plate analysis that are regarded as indicators of fluid retention, peripheral neuropathy, and thermal threshold, respectively, for toxicological tests. In summary, compared with Taxotere™, Nufs-DTX, which was generated by our new platform technology using lipid, supercritical fluid, and carbon dioxide (CO2), maintained its biochemical properties as a cytotoxic agent and had better tumor targeting ability, better in vivo therapeutic effect, and less toxicity, thereby overcoming the current hurdles of traditional drugs.

Skill acquisition and retention in automated external defibrillator (AED) use and CPR by lay responders: a prospective study.

PubMed

Woollard, Malcolm; Whitfeild, Richard; Smith, Anna; Colquhoun, Michael; Newcombe, Robert G; Vetteer, Norman; Chamberlain, Douglas

2004-01-01

This prospective study evaluated the acquisition and retention of skills in cardio-pulmonary resuscitation (CPR) and the use of the automated external defibrillator (AED) by lay volunteers involved in the Department of Health, England National Defibrillator Programme. One hundred and twelve trainees were tested immediately before and after and initial 4-h class; 76 were similarly reassessed at refresher training 6 months later. A standardised test scenario that required assessment of the casualty, CPR and the use of on AED was evaluated using recording manikin data and video recordings. Before training only 44% of subjects delivered a shock. Afterwards, all did so and the average delay to first shock was reduced by 57 s. All trainees placed the defibrillator electrodes in an "acceptable" position after training, but very few did so in the recommended "ideal" position. After refresher training 80% of subjects used the correct sequence for CPR and shock delivery, yet a third failed to perform adequate safety checks before all shocks. The trainees self-assessed AED competence score was 86 (scale 0-100) after the initial class and their confidence that they would act in a real emergency was rated at a similar level. Initial training improved performance of all CPR skills, although all except compression rate had deteriorated after 6 months. The proportion of subjects able to correctly perform most CPR skill was higher following refresher training that after the initial class. Although this course was judged to be effective in teaching delivery of counter-shocks, the need was identified for more emphasis on positioning of electrodes, pre-shock safety checks, airway opening, ventilation volume, checking for signs of a circulation, hand positioning, and depth and rate of chest compressions.

Motor skill learning is associated with diffusion characteristics of white matter in individuals with chronic stroke.

PubMed

Borich, Michael R; Brown, Katlyn E; Boyd, Lara A

2014-07-01

Imaging advances allow investigation of white matter after stroke; a growing body of literature has shown links between diffusion-based measures of white matter microstructure and motor function. However, the relationship between these measures and motor skill learning has not been considered in individuals with stroke. The aim of this study was to investigate the relationships between posttraining white matter microstructural status, as indexed by diffusion tensor imaging within the ipsilesional posterior limb of the internal capsule (PLIC), and learning of a novel motor task in individuals with chronic stroke. A total of 13 participants with chronic stroke and 9 healthy controls practiced a visuomotor pursuit task across 5 sessions. Change in motor behavior associated with learning was indexed by comparing baseline performance with a delayed retention test. Fractional anisotropy (FA) indexed at the retention test was the primary diffusion tensor imaging-derived outcome measure. In individuals with chronic stroke, we discovered an association between posttraining ipsilesional PLIC FA and the magnitude of change associated with motor learning; hierarchical multiple linear regression analyses revealed that the combination of age, time poststroke, and ipsilesional PLIC FA posttraining was associated with motor learning-related change (R = 0.649; P = 0.02). Baseline motor performance was not related to posttraining ipsilesional PLIC FA. Diffusion characteristics of posttraining ipsilesional PLIC were linked to the magnitude of change in skilled motor behavior. These results imply that the microstructural properties of regional white matter indexed by diffusion behavior may be an important factor to consider when determining potential response to rehabilitation in persons with stroke. (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A59) for more insights from the authors.

Nicotinic α7 and α4β2 agonists enhance the formation and retrieval of recognition memory: Potential mechanisms for cognitive performance enhancement in neurological and psychiatric disorders.

PubMed

McLean, Samantha L; Grayson, Ben; Marsh, Samuel; Zarroug, Samah H O; Harte, Michael K; Neill, Jo C

2016-04-01

Cholinergic dysfunction has been shown to be central to the pathophysiology of Alzheimer's disease and has also been postulated to contribute to cognitive dysfunction observed in various psychiatric disorders, including schizophrenia. Deficits are found across a number of cognitive domains and in spite of several attempts to develop new therapies, these remain an unmet clinical need. In the current study we investigated the efficacy of donepezil, risperidone and selective nicotinic α7 and α4β2 receptor agonists to reverse a delay-induced deficit in recognition memory. Adult female Hooded Lister rats received drug treatments and were tested in the novel object recognition (NOR) task following a 6h inter-trial interval (ITI). In all treatment groups, there was no preference for the left or right identical objects in the acquisition trial. Risperidone failed to enhance recognition memory in this paradigm whereas donepezil was effective such that rats discriminated between the novel and familiar object in the retention trial following a 6h ITI. Although a narrow dose range of PNU-282987 and RJR-2403 was tested, only one dose of each increased recognition memory, the highest dose of PNU-282987 (10mg/kg) and the lowest dose of RJR-2403 (0.1mg/kg), indicative of enhanced cognitive performance. Interestingly, these compounds were also efficacious when administered either before the acquisition or the retention trial of the task, suggesting an important role for nicotinic receptor subtypes in the formation and retrieval of recognition memory. Copyright © 2016. Published by Elsevier B.V.

The electrophysiological correlates of recent and remote recollection.

PubMed

Roberts, J S; Tsivilis, D; Mayes, A R

2013-09-01

Research using event related potentials (ERPs) to explore recognition memory has linked late parietal old/new effects to the recollection of episodic information. In the vast majority of these studies, the retrieval phase immediately follows encoding and consequently, very little is known about the ERP correlates of long term recollection. This is despite the fact that in other areas of the memory literature there is considerable interest in consolidation theories and the way episodic memory changes over time. The present study explored the idea that consolidation and forgetting processes operating over a moderate retention interval can alter the ERP markers of recollection memory. A remember/know test probed memory for stimuli studied either 15 minutes (recent memory) or 1 week (remote memory) prior to the test phase. Results revealed an attenuated late parietal effect for remote compared to recent remember responses, a finding that remained significant even when these recognition judgments were matched for reaction time. Experiments 2a and 2b identified characteristic differences between recent and remote recognition at the behavioural level. The 1 week delay produced an overall decline in recognition confidence and a dramatic loss of episodic detail. These behavioural changes are thought to underlie the ERP effects reported in the first experiment. The results highlight that although the neural basis of memory may exhibit significant changes as the length of the retention interval increases, it is important to consider the extent to which this is a direct effect of time or an indirect effect due to changes in memory quality, such as the amount of detail that can be recollected. © 2013 Elsevier Ltd. All rights reserved.

Load-Bearing Capacity and Retention of Newly Developed Micro-Locking Implant Prosthetic System: An In Vitro Pilot Study.

PubMed

Choi, Jae-Won; Choi, Kyung-Hee; Chae, Hee-Jin; Chae, Sung-Ki; Bae, Eun-Bin; Lee, Jin-Ju; Lee, So-Hyoun; Jeong, Chang-Mo; Huh, Jung-Bo

2018-04-06

The aim of this study was to introduce the newly developed micro-locking implant prosthetic system and to evaluate the resulting its characteristics. To evaluate load-bearing capacity, 25 implants were divided into five groups: external-hexagon connection (EH), internal-octagon connection (IO), internal-hexagon connection (IH), one-body implant (OB), micro-locking implant system (ML). The maximum compressive load was measured using a universal testing machine (UTM) according to the ISO 14801. Retention was evaluated in two experiments: (1) a tensile test of the structure modifications of the components (attachment and implant) and (2) a tensile test after cyclic loading (total 5,000,000 cycles, 100 N, 2 Hz). The load-bearing capacity of the ML group was not significantly different from the other groups ( p > 0.05). The number of balls in the attachment and the presence of a hexagonal receptacle did not show a significant correlation with retention ( p > 0.05), but the shape of the retentive groove in the implant post had a statistically significant effect on retention ( p < 0.05). On the other hand, the retention loss was observed during the initial 1,000,000 cycles, but an overall constant retention was maintained afterward. Various preclinical studies on this novel micro-locking implant prosthetic system should continue so that it can be applied in clinical practice.

Load-Bearing Capacity and Retention of Newly Developed Micro-Locking Implant Prosthetic System: An In Vitro Pilot Study

PubMed Central

Choi, Kyung-Hee; Chae, Hee-Jin; Chae, Sung-Ki; Bae, Eun-Bin; Lee, Jin-Ju; Lee, So-Hyoun; Jeong, Chang-Mo; Huh, Jung-Bo

2018-01-01

The aim of this study was to introduce the newly developed micro-locking implant prosthetic system and to evaluate the resulting its characteristics. To evaluate load-bearing capacity, 25 implants were divided into five groups: external-hexagon connection (EH), internal-octagon connection (IO), internal-hexagon connection (IH), one-body implant (OB), micro-locking implant system (ML). The maximum compressive load was measured using a universal testing machine (UTM) according to the ISO 14801. Retention was evaluated in two experiments: (1) a tensile test of the structure modifications of the components (attachment and implant) and (2) a tensile test after cyclic loading (total 5,000,000 cycles, 100 N, 2 Hz). The load-bearing capacity of the ML group was not significantly different from the other groups (p > 0.05). The number of balls in the attachment and the presence of a hexagonal receptacle did not show a significant correlation with retention (p > 0.05), but the shape of the retentive groove in the implant post had a statistically significant effect on retention (p < 0.05). On the other hand, the retention loss was observed during the initial 1,000,000 cycles, but an overall constant retention was maintained afterward. Various preclinical studies on this novel micro-locking implant prosthetic system should continue so that it can be applied in clinical practice. PMID:29642407

Electrical Characterization of the RCA CDP1822SD Random Access Memory, Volume 1, Appendix a

NASA Technical Reports Server (NTRS)

Klute, A.

1979-01-01

Electrical characteristization tests were performed on 35 RCA CDP1822SD, 256-by-4-bit, CMOS, random access memories. The tests included three functional tests, AC and DC parametric tests, a series of schmoo plots, rise/fall time screening, and a data retention test. All tests were performed on an automated IC test system with temperatures controlled by a thermal airstream unit. All the functional tests, the data retention test, and the AC and DC parametric tests were performed at ambient temperatures of 25 C, -20 C, -55 C, 85 C, and 125 C. The schmoo plots were performed at ambient temperatures of 25 C, -55 C, and 125 C. The data retention test was performed at 25 C. Five devices failed one or more functional tests and four of these devices failed to meet the expected limits of a number of AC parametric tests. Some of the schmoo plots indicated a small degree of interaction between parameters.

[Results of the 75selenium homotaurocholic acid retention test (SeHCAT test) in diagnosis of diarrhea].

PubMed

Balzer, K; Schmitt, G; Reiners, C; Goebell, H

1995-01-15

For that reason absorption of bile acids was investigated using the 75Se-homotaurocholate (SeHCAT) in 239 patients with diarrhoea. SeHCAT retention time was measured as 7 day retention time in a whole body counter. An intact bile acid absorption (negative SeHCAT test) was confirmed in 23 healthy volunteers within the range of 11 to 50% (mean +/- double standard deviation). In 135 patients with a possible type I bile salt malabsorption the SeHCAT test was positive in 78%, thus indicating bile salt malabsorption. The test is very sensitive detecting bile salt malabsorption in Crohn's disease, identifying ileal disease more precisely than radiology. The SeHCAT test ascertained type II primary bile salt malabsorption in 7 patients, as well as type III bile salt malabsorption in patients (9 out of 28) with cholecystectomy, vagotomy, partial gastrectomy and chronic pancreatitis. In addition, a positive SeHCAT test indicating bile acid malabsorption was found in 5 out of 11 patients with irritable syndrome, diarrhoeic form, and in 4 out of 12 patients with lactose intolerance. SeHCAT retention should be measured routinely in patients with chronic diarrhoea for which the cause is not obvious.

Collaborative Testing Improves Performance but Not Content Retention in a Large-Enrollment Introductory Biology Class

PubMed Central

Leight, Hayley; Saunders, Cheston; Calkins, Robin; Withers, Michelle

2012-01-01

Collaborative testing has been shown to improve performance but not always content retention. In this study, we investigated whether collaborative testing could improve both performance and content retention in a large, introductory biology course. Students were semirandomly divided into two groups based on their performances on exam 1. Each group contained equal numbers of students scoring in each grade category (“A”–“F”) on exam 1. All students completed each of the four exams of the semester as individuals. For exam 2, one group took the exam a second time in small groups immediately following the individually administered test. The other group followed this same format for exam 3. Individual and group exam scores were compared to determine differences in performance. All but exam 1 contained a subset of cumulative questions from the previous exam. Performances on the cumulative questions for exams 3 and 4 were compared for the two groups to determine whether there were significant differences in content retention. Even though group test scores were significantly higher than individual test scores, students who participated in collaborative testing performed no differently on cumulative questions than students who took the previous exam as individuals. PMID:23222835

Providing Extrinsic Reward for Test Performance Undermines Long-Term Memory Acquisition.

PubMed

Kuhbandner, Christof; Aslan, Alp; Emmerdinger, Kathrin; Murayama, Kou

2016-01-01

Based on numerous studies showing that testing studied material can improve long-term retention more than restudying the same material, it is often suggested that the number of tests in education should be increased to enhance knowledge acquisition. However, testing in real-life educational settings often entails a high degree of extrinsic motivation of learners due to the common practice of placing important consequences on the outcome of a test. Such an effect on the motivation of learners may undermine the beneficial effects of testing on long-term memory because it has been shown that extrinsic motivation can reduce the quality of learning. To examine this issue, participants learned foreign language vocabulary words, followed by an immediate test in which one-third of the words were tested and one-third restudied. To manipulate extrinsic motivation during immediate testing, participants received either monetary reward contingent on test performance or no reward. After 1 week, memory for all words was tested. In the immediate test, reward reduced correct recall and increased commission errors, indicating that reward reduced the number of items that can benefit from successful retrieval. The results in the delayed test revealed that reward additionally reduced the gain received from successful retrieval because memory for initially successfully retrieved words was lower in the reward condition. However, testing was still more effective than restudying under reward conditions because reward undermined long-term memory for concurrently restudied material as well. These findings indicate that providing performance-contingent reward in a test can undermine long-term knowledge acquisition.

Providing Extrinsic Reward for Test Performance Undermines Long-Term Memory Acquisition

PubMed Central

Kuhbandner, Christof; Aslan, Alp; Emmerdinger, Kathrin; Murayama, Kou

2016-01-01

Based on numerous studies showing that testing studied material can improve long-term retention more than restudying the same material, it is often suggested that the number of tests in education should be increased to enhance knowledge acquisition. However, testing in real-life educational settings often entails a high degree of extrinsic motivation of learners due to the common practice of placing important consequences on the outcome of a test. Such an effect on the motivation of learners may undermine the beneficial effects of testing on long-term memory because it has been shown that extrinsic motivation can reduce the quality of learning. To examine this issue, participants learned foreign language vocabulary words, followed by an immediate test in which one-third of the words were tested and one-third restudied. To manipulate extrinsic motivation during immediate testing, participants received either monetary reward contingent on test performance or no reward. After 1 week, memory for all words was tested. In the immediate test, reward reduced correct recall and increased commission errors, indicating that reward reduced the number of items that can benefit from successful retrieval. The results in the delayed test revealed that reward additionally reduced the gain received from successful retrieval because memory for initially successfully retrieved words was lower in the reward condition. However, testing was still more effective than restudying under reward conditions because reward undermined long-term memory for concurrently restudied material as well. These findings indicate that providing performance–contingent reward in a test can undermine long-term knowledge acquisition. PMID:26869978

Slow Physical Growth, Delayed Reflex Ontogeny, and Permanent Behavioral as Well as Cognitive Impairments in Rats Following Intra-generational Protein Malnutrition

PubMed Central

Naik, Aijaz A.; Patro, Ishan K.; Patro, Nisha

2015-01-01

Environmental stressors including protein malnutrition (PMN) during pre-, neo- and post-natal age have been documented to affect cognitive development and cause increased susceptibility to neuropsychiatric disorders. Most studies have addressed either of the three windows and that does not emulate the clinical conditions of intra-uterine growth restriction (IUGR). Such data fail to provide a complete picture of the behavioral alterations in the F1 generation. The present study thus addresses the larger window from gestation to F1 generation, a new model of intra-generational PMN. Naive Sprague Dawley (SD) dams pre-gestationally switched to LP (8% protein) or HP (20% protein) diets for 45 days were bred and maintained throughout gestation on same diets. Pups born (HP/LP dams) were maintained on the respective diets post-weaningly. The present study aimed to show the sex specific differences in the neurobehavioral evolution and behavioral phenotype of the HP/LP F1 generation pups. A battery of neurodevelopmental reflex tests, behavioral (Open field and forelimb gripstrength test), and cognitive [Elevated plus maze (EPM) and Morris water maze (MWM)] assays were performed. A decelerated growth curve with significantly restricted body and brain weight, delays in apparition of neuro-reflexes and poor performance in the LP group rats was recorded. Intra-generational PMN induced poor habituation-with-time in novel environment exploration, low anxiety and hyperactive like profile in open field test in young and adult rats. The study revealed poor forelimb neuromuscular strength in LP F1 pups till adulthood. Group occupancy plots in MWM test revealed hyperactivity with poor learning, impaired memory retention and integration, thus modeling the signs of early onset Alzehemier phenotype. In addition, a gender specific effect of LP diet with severity in males and favoring female sex was also noticed. PMID:26696810

Sleep-dependent consolidation patterns reveal insights into episodic memory structure.

PubMed

Oyanedel, Carlos N; Sawangjit, Anuck; Born, Jan; Inostroza, Marion

2018-05-18

Episodic memory formation is considered a genuinely hippocampal function. Its study in rodents has relied on two different task paradigms, i.e. the so called "what-where-when" (WW-When) task and "what-where-which" (WW-Which) task. The WW-When task aims to assess the memory for an episode as an event bound into its context defined by spatial and distinct temporal information, the WW-Which task lacks the temporal component and introduces, instead, an "occasion setter" marking the broader contextual configuration in which the event occurred. Whether both tasks measure episodic memory in an equivalent manner in terms of recollection has been controversially discussed. Here, we compared in two groups of rats the consolidating effects of sleep on episodic-like memory between both task paradigms. Sampling and test phases were separated by a 90-min morning retention interval which did or did not allow for spontaneous sleep. Results show that sleep is crucial for the consolidation of the memory on both tasks. However, consolidating effects of sleep were stronger for the WW-Which than WW-When task. Comparing performance during the post-sleep test phase revealed that WW-When memory only gradually emerged during the 3-min test period whereas WW-Which memory was readily expressed already from the first minute onward. Separate analysis of the temporal and spatial components of WW-When performance showed that the delayed episodic memory on this task originated from the temporal component which also did not emerge until the third minute of the test phase, whereas the spatial component already showed up in the first minute. In conclusion, sleep differentially affects consolidation on the two episodic-like memory tasks, with the delayed expression of WW-When memory after sleep resulting from preferential coverage of temporal aspects by this task. Copyright © 2018. Published by Elsevier Inc.

Gall-bladder and colonic retention of SeHCAT: a re-evaluation.

PubMed

Merrick, M V

1994-09-01

A number of suggested alternatives and emendations to the 7-day SeHCAT retention test have been compared with whole-body counting. It was found that correction for colonic retention is an unnecessary complication in patients with diarrhoea and that imaging either of the gall-bladder or of the distribution of activity in the intestines at 24 h does not add useful information to the standard 7-day retention measurement. Neither could the patterns of colonic uptake identified in patients following extensive ideal resection or radiotherapy be reproduced in patients with idiopathic diarrhoea. Sadly it must be concluded that neither of these shortened techniques is of clinical value in patients with intact small bowel and that there remains no reliable alternative to the 7-day Se HCAT retention test. The simplest technique the best.

Encoding Deficits Impede Word Learning and Memory in Adults With Developmental Language Disorders

PubMed Central

Gordon, Katherine; Eden, Nichole; Arbisi-Kelm, Tim; Oleson, Jacob

2017-01-01

Purpose The aim of this study was to determine whether the word-learning challenges associated with developmental language disorder (DLD) result from encoding or retention deficits. Method In Study 1, 59 postsecondary students with DLD and 60 with normal development (ND) took the California Verbal Learning Test–Second Edition, Adult Version (Delis, Kramer, Kaplan, & Ober, 2000). In Study 2, 23 postsecondary students with DLD and 24 with ND attempted to learn 9 novel words in each of 3 training conditions: uncued test, cued test, and no test (passive study). Retention was measured 1 day and 1 week later. Results By the end of training, students with DLD had encoded fewer familiar words (Study 1) and fewer novel words (Study 2) than their ND peers as evinced by word recall. They also demonstrated poorer encoding as evinced by slower growth in recall from Trials 1 to 2 (Studies 1 and 2), less semantic clustering of recalled words, and poorer recognition (Study 1). The DLD and ND groups were similar in the relative amount of information they could recall after retention periods of 5 and 20 min (Study 1). After a 1-day retention period, the DLD group recalled less information that had been encoded via passive study, but they performed as well as their ND peers when recalling information that had been encoded via tests (Study 2). Compared to passive study, encoding via tests also resulted in more robust lexical engagement after a 1-week retention for DLD and ND groups. Conclusions Encoding, not retention, is the problematic stage of word learning for adults with DLD. Self-testing with feedback lessens the deficit. Supplemental Materials https://doi.org/10.23641/asha.5435200 PMID:28980007

Elevated cortisol levels in Cushing's disease are associated with cognitive decrements.

PubMed

Starkman, M N; Giordani, B; Berent, S; Schork, M A; Schteingart, D E

2001-01-01

The objective of this study was to use Cushing's disease as a unique human model to elucidate the cognitive deficits resulting from exposure to chronic stress-level elevations of endogenous cortisol. Forty-eight patients with a first episode of acute, untreated Cushing's disease and 38 healthy control subjects were studied. Scores for four of five verbal IQ subtests were significantly lower in patients with Cushing's disease; their scores were significantly lower for only one nonverbal performance IQ subtest (block design). Verbal, but not visual, learning and delayed recall at 30 minutes were significantly decreased among patients with Cushing's disease. Although verbal delayed recall was significantly lower in these patients, the retention index (percentage), which compares the amount of initially learned material to that recalled after the delay, was not significantly decreased. There was no significant association between depression scores and cognitive performance. A higher degree of cortisol elevation was associated with poorer performance on several subtests of learning, delayed recall, and visual-spatial ability. Chronically elevated levels of glucocorticoids have deleterious effects on particular domains of cognition. Verbal learning and other verbal functions seem more vulnerable than nonverbal functions. The results suggest that both the neocortex and hippocampus are affected.

Associations among hypothalamus-pituitary-adrenal axis function, novelty seeking, and retention in methadone maintenance therapy for heroin dependency.

PubMed

Lin, Shih-Hsien; Chen, Wei Tseng; Chen, Kao Chin; Lee, Sheng-Yu; Lee, I Hui; Chen, Po See; Yeh, Tzung Lieh; Lu, Ru-Band; Yang, Yen Kuang

2013-01-01

The efficacy of methadone maintenance therapy for heroin dependence is compromised by the low retention rate. Hypothalamus-pituitary-adrenal (HPA) axis function, which is associated with stress response, and novelty seeking (NS), a personality trait associated with low dopaminergic activity, may play roles in retention. We conducted a prospective study in which HPA axis function and NS were assessed by the dexamethasone suppression test and the Tridimensional Personality Questionnaire at baseline, respectively. The retention rate was assessed at the half- and 1-year points of methadone maintenance therapy. A low suppression rate of dexamethasone suppression test (D%) was associated with a high level of NS. A low D% was associated with half-year dropout, whereas a high level of NS was associated with 1-year dropout. Survival analysis confirmed that D% and NS were significant time-dependent covariates for retention. The findings showed that HPA axis function and NA were associated with retention at different time points.

The effects of perceived USB-delay for sensor and embedded system development.

PubMed

Du, J; Kade, D; Gerdtman, C; Ozcan, O; Linden, M

2016-08-01

Perceiving delay in computer input devices is a problem which gets even more eminent when being used in healthcare applications and/or in small, embedded systems. Therefore, the amount of delay found as acceptable when using computer input devices was investigated in this paper. A device was developed to perform a benchmark test for the perception of delay. The delay can be set from 0 to 999 milliseconds (ms) between a receiving computer and an available USB-device. The USB-device can be a mouse, a keyboard or some other type of USB-connected input device. Feedback from performed user tests with 36 people form the basis for the determination of time limitations for the USB data processing in microprocessors and embedded systems without users' noticing the delay. For this paper, tests were performed with a personal computer and a common computer mouse, testing the perception of delays between 0 and 500 ms. The results of our user tests show that perceived delays up to 150 ms were acceptable and delays larger than 300 ms were not acceptable at all.

A homozygous mutation in the stem II domain of RNU4ATAC causes typical Roifman syndrome.

PubMed

Dinur Schejter, Yael; Ovadia, Adi; Alexandrova, Roumiana; Thiruvahindrapuram, Bhooma; Pereira, Sergio L; Manson, David E; Vincent, Ajoy; Merico, Daniele; Roifman, Chaim M

2017-01-01

Roifman syndrome (OMIM# 616651) is a complex syndrome encompassing skeletal dysplasia, immunodeficiency, retinal dystrophy and developmental delay, and is caused by compound heterozygous mutations involving the Stem II region and one of the other domains of the RNU4ATAC gene. This small nuclear RNA gene is essential for minor intron splicing. The Canadian Centre for Primary Immunodeficiency Registry and Repository were used to derive patient information as well as tissues. Utilising RNA sequencing methodologies, we analysed samples from patients with Roifman syndrome and assessed intron retention. We demonstrate that a homozygous mutation in Stem II is sufficient to cause the full spectrum of features associated with typical Roifman syndrome. Further, we demonstrate the same pattern of aberration in minor intron retention as found in cases with compound heterozygous mutations.

Assessing the HIV Care Continuum in Latin America: progress in clinical retention, cART use and viral suppression

PubMed Central

Rebeiro, Peter F; Cesar, Carina; Shepherd, Bryan E; De Boni, Raquel B; Cortés, Claudia P; Rodriguez, Fernanda; Belaunzarán-Zamudio, Pablo; Pape, Jean W; Padgett, Denis; Hoces, Daniel; McGowan, Catherine C; Cahn, Pedro

2016-01-01

Introduction We assessed trends in HIV Care Continuum outcomes associated with delayed disease progression and reduced transmission within a large Latin American cohort over a decade: clinical retention, combination antiretroviral therapy (cART) use and viral suppression (VS). Methods Adults from Caribbean, Central and South America network for HIV epidemiology clinical cohorts in seven countries contributed data between 2003 and 2012. Retention was defined as two or more HIV care visits annually, >90 days apart. cART was defined as prescription of three or more antiretroviral agents annually. VS was defined as HIV-1 RNA <200 copies/mL at last measurement annually. cART and VS denominators were subjects with at least one visit annually. Multivariable modified Poisson regression was used to assess temporal trends and examine associations between age, sex, HIV transmission mode, cohort, calendar year and time in care. Results Among 18,799 individuals in retention analyses, 14,380 in cART analyses and 13,330 in VS analyses, differences existed between those meeting indicator definitions versus those not by most characteristics. Retention, cART and VS significantly improved from 2003 to 2012 (63 to 77%, 74 to 91% and 53 to 82%, respectively; p<0.05, each). Female sex (risk ratio (RR)=0.97 vs. males) and injection drug use as HIV transmission mode (RR=0.83 vs. male sexual contact with males (MSM)) were significantly associated with lower retention, but unrelated with cART or VS. MSM (RR=0.96) significantly decreased the probability of cART compared with heterosexual transmission. Conclusions HIV Care Continuum outcomes improved over time in Latin America, though disparities for vulnerable groups remain. Efforts must be made to increase retention, cART and VS, while engaging in additional research to sustain progress in these settings. PMID:27065108

Oral Health Literacy and Retention of Health Information Among Pregnant Women: A Randomised Controlled Trial.

PubMed

Vilella, Karina Duarte; Fraiz, Fabian Calixto; Benelli, Elaine Machado; Assunção, Luciana Reichert da Silva

This study evaluated the effect of oral health literacy (OHL) on the retention of health information in pregnant women. A total of 175 pregnant women were randomly assigned to standard oral (spoken), written and control intervention groups. With the exception of the control group, the interventions investigated the eating habits and oral hygiene among children under 2 years of age. The participants' answers before the interventions (pre-test), 15 min after the interventions (post-test) and 4 weeks after the interventions (follow-up test) were used to estimate the knowledge score (KS). Information acquisition was determined by comparing pre-test and post-test results, while retention of information was based comparing pre-test and follow-up test results. OHL was analysed by BREALD-30. The data were assessed by nonparametric tests and Poisson regression models with robust variance (α = 0.05). By the end of the follow-up period, 162 pregnant women had been assessed. The BREALD-30 mean was 22.3 (SD = 4.80). Regardless of the type of intervention, pregnant women with low OHL had lower knowledge scores in the three assessments. Participants with low OHL showed higher acquisition and retention of information in the standard oral health intervention. Multiple regression models demonstrated that OHL was independently associated with KS, age, socioeconomic status and type of intervention. The results suggest a negative effect of low OHL on retention of information. Only the standard, spoken oral health intervention could address the differences in literacy levels.

Very long-term retention of basic science knowledge in doctors after graduation.

PubMed

Custers, Eugène J F M; Ten Cate, Olle T J

2011-04-01

Despite frequent complaints that biomedical knowledge is quickly forgotten after it has been learned, few investigations of actual long-term retention of basic science knowledge have been conducted in the medical domain. Our aim was to illuminate the long-term retention of basic science knowledge, particularly of unrehearsed knowledge. Using a cross-sectional study design, medical students and doctors in the Netherlands were tested for retention of basic science knowledge. Relationships between retention interval and proportion of correct answers on a knowledge test were investigated. The popular notion that most of basic science knowledge is forgotten shortly after graduation is not supported by our findings. With respect to the full test scores, which reflect a composite of unrehearsed and rehearsed knowledge, performance decreased from approximately 40% correct answers for students still in medical school, to 25-30% correct answers for doctors after many years of practice. When rehearsal during the retention interval is controlled for, it appears that little knowledge is lost for 1.5-2 years after it was last used; from then on, retention is best described by a negatively accelerated (logarithmic) forgetting curve. After ≥ 25 years, retention levels were in the range of 15-20%. Conclusions about the forgetting of unrehearsed knowledge in this study are in line with findings reported in other domains: it proceeds in accordance with the Ebbinghaus curve for meaningful material, except that in our findings the 'downward' part appears to start later than in most other studies. The limitations of the study are discussed and possible ramifications for medical education are proposed. © Blackwell Publishing Ltd 2011.

Effect of Unsaturated Flow on Delayed Response of Unconfined Aquifiers to Pumping

NASA Astrophysics Data System (ADS)

Tartakovsky, G.; Neuman, S. P.

2005-12-01

A new analytical solution is presented for the delayed response process characterizing flow to a partially penetrating well in an unconfined aquifer. The new solution generalizes that of Neuman [1972, 1974] by accounting for unsaturated flow above the water table. Axially symmetric three-dimensional flow in the unsaturated zone is described by a linearized version of Richards' equation in which hydraulic conductivity and water content vary exponentially with incremental capillary pressure head relative to its air entry value (defining the interface between the saturated and unsaturated zones). Unsaturated soil properties are characterized by an exponent κ having the dimension of inverse length and a dimensionless exponent κD = κb where b is initial saturated thickness. Our treatment of the unsaturated zone is similar to that of Kroszynski and Dagan [1975] who however have ignored internal (artesian) aquifer storage. It has been suggested by Boulton [1954, 1963, 1970] and Neuman [1972, 1974], and is confirmed by our solution, that internal storage is required to reproduce the early increase in drawdown characterizing delayed response to pumping in typical aquifers. According to our new solution such aquifers are characterized by relatively large κ_ D values, typically 10 or larger; in the limit as κD tends to infinity (the soil unsaturated water retention capacity becomes insignificant and/or aquifer thickness become large), unsaturated flow becomes unimportant and our solution reduces to that of Neuman. In typical cases corresponding to κD larger than or equal to 10, unsaturated flow is found to have little impact on early and late dimensionless time behaviors of drawdown measured wholly or in part at some distance below the water table; unsaturated flow causes drawdown to increase slightly at intermediate dimensionless time values that represent transition from an early artesian dominated to a late water-table dominated flow regime. The increase in drawdown during this transition period is caused by delayed drainage from the unsaturated zone, whose relatively small effect is superimposed on the more pronounced phenomenon of delay in water table decline relative to artesian head drops below it. Delayed drainage from the unsaturated zone becomes less and less important as κD increases; as it approaches infinity, this effect dies out completely and drawdown is controlled entirely by delayed decline in the water table. The unsaturated zone has major impact on drawdown at intermediate time, and significant impact at early and late times, in the atypical case of small κD values (1 or less), becoming the dominant factor as κD approaches zero (the soil water retention capacity becomes very large and/or saturated thickness becomes insignificant).

Laboratory based instruction in Pakistan: Comparative evaluation of three laboratory instruction methods in biological science at higher secondary school level

NASA Astrophysics Data System (ADS)

Cheema, Tabinda Shahid

This study of laboratory based instruction at higher secondary school level was an attempt to gain some insight into the effectiveness of three laboratory instruction methods: cooperative group instruction method, individualised instruction method and lecture demonstration method on biology achievement and retention. A Randomised subjects, Pre-test Post-test Comparative Methods Design was applied. Three groups of students from a year 11 class in Pakistan conducted experiments using the different laboratory instruction methods. Pre-tests, achievement tests after the experiments and retention tests one month later were administered. Results showed no significant difference between the groups on total achievement and retention, nor was there any significant difference on knowledge and comprehension test scores or skills performance. Future research investigating a similar problem is suggested.

Home healthcare nurse retention and patient outcome model: discussion and model development.

PubMed

Ellenbecker, Carol Hall; Cushman, Margaret

2012-08-01

This paper discusses additions to an empirically tested model of home healthcare nurse retention. An argument is made that the variables of shared decision-making and organizational commitment be added to the model based on the authors' previous research and additional evidence from the literature. Previous research testing the home healthcare nurse retention model established empirical relationships between nurse, agency, and area characteristics to nurse job satisfaction, intent to stay, and retention. Unexplained model variance prompted a new literature search to augment understanding of nurse retention and patient and agency outcomes. Data come from the authors' previous research, and a literature search from 1990 to 2011 on the topics organizational commitment, shared decision-making, nurse retention, patient outcomes and agency performance. The literature provides a rationale for the additional variables of shared decision-making and affective and continuous organizational commitment, linking these variables to nurse job satisfaction, nurse intent to stay, nurse retention and patient outcomes and agency performance. Implications for nursing.  The new variables in the model suggest that all agencies, even those not struggling to retain nurses, should develop interventions to enhance nurse job satisfaction to assure quality patient outcomes. The new nurse retention and patient outcome model increases our understanding of nurse retention. An understanding of the relationship among these variables will guide future research and the development of interventions to create and maintain nursing work environments that contribute to nurse affective agency commitment, nurse retention and quality of patient outcomes. © 2011 Blackwell Publishing Ltd.

Effect of Incentives and Mailing Features on Online Health Program Enrollment

PubMed Central

Alexander, Gwen L.; Divine, George W.; Couper, Mick P.; McClure, Jennifer B.; Stopponi, Melanie A.; Fortman, Kristine K.; Tolsma, Dennis D.; Strecher, Victor J.; Johnson, Christine Cole

2008-01-01

Background With the growing use of Internet-based interventions, strategies are needed to encourage broader participation. This study examined the effects of combinations of monetary incentives and mailing characteristics on enrollment, retention, and cost effectiveness for an online health program. Methods In 2004, a recruitment letter was mailed to randomly selected Midwestern integrated health system members aged 21–65 and stratified by gender and race/ethnicity; recipients were randomly pre-assigned to one of 24 combinations of incentives and various mailing characteristics. Enrollment and 3-month retention rates were measured by completion of online surveys. Analysis, completed in 2005, compared enrollment and retention factors using t tests and chi-square tests. Multivariate logistic regression modeling assessed the probability of enrollment and retention. Results Of 12,289 subjects, 531 (4.3%) enrolled online, ranging from 1% to 11% by incentive combination. Highest enrollment occurred with unconditional incentives, and responses varied by gender. Retention rates ranged from 0% to 100%, with highest retention linked to higher-value incentives. The combination of a $2 bill prepaid incentive and the promise of $20 for retention (10% enrollment and 71% retention) was optimal, considering per-subject recruitment costs ($32 enrollment, $70 retention) and equivalent enrollment by gender and race/ethnicity. Conclusions Cash incentives improved enrollment in an online health program. Men and women responded differently to mailing characteristics and incentives. Including a small prepaid monetary incentive ($2 or $5) and revealing the higher promised-retention incentive was cost effective and boosted enrollment. PMID:18407004

Flip-flop resolving time test circuit

NASA Technical Reports Server (NTRS)

Rosenberger, F.; Chaney, T. J.

1982-01-01

Integrated circuit (IC) flip-flop resolving time parameters are measured by wafer probing, without need of dicing or bonding, throught the incorporation of test structures on an IC together with the flip-flop to be measured. Several delays that are fabricated as part of the test circuit, including a voltage-controlled delay with a resolution of a few picosecs, are calibrated as part of the test procedure by integrating them into, and out of, the delay path of a ring oscillator. Each of the delay values is calculated by subtracting the period of the ring oscillator with the delay omitted from the period with the delay included. The delay measurement technique is sufficiently general for other applications. The technique is illustrated for the case of the flip-flop parameters of a 5-micron feature size NMOS circuit.

Pilot study demonstrating effectiveness of targeted education to improve informed consent understanding in AIDS clinical trials.

PubMed

Sengupta, Sohini; Lo, Bernard; Strauss, Ronald P; Eron, Joseph; Gifford, Allen L

2011-11-01

Assessing and improving informed consent understanding is equally important as obtaining consent from participants in clinical trial research, but developing interventions to target gaps in participants' informed consent understanding remains a challenge. We used a randomized controlled study design to pilot test an educational intervention to improve actual informed consent understanding of new enrollees in the Adult AIDS Clinical Trial Group (AACTG). Questionnaires were administered to 24 enrollees to assess their baseline understanding on eight elements of informed consent associated with AIDS clinical trials. Enrollees who scored 18/21(85%) or less were randomly assigned to in-person, targeted education (intervention), or delayed education (control). Two follow-up assessments were administered. Repeated measures ANOVA was performed to determine intervention effectiveness in improving actual informed consent understanding over time. Actual understanding improved at the immediate post-intervention time point with a significant score difference of 2.5 when comparing the intervention and delayed groups. In addition, there was a significant score difference of 3.2 when comparing baseline to three-month follow-up for the two groups, suggesting a statistically significant intervention effect to improve actual understanding of the basic elements of informed consent. The findings demonstrated that one-time targeted education can improve actual informed consent understanding one week after the intervention, but retention of these concepts may require periodic monitoring to ensure comprehension throughout the course of a clinical trial.

Acute exposure to blue wavelength light during memory consolidation improves verbal memory performance.

PubMed

Alkozei, Anna; Smith, Ryan; Dailey, Natalie S; Bajaj, Sahil; Killgore, William D S

2017-01-01

Acute exposure to light within the blue wavelengths has been shown to enhance alertness and vigilance, and lead to improved speed on reaction time tasks, possibly due to activation of the noradrenergic system. It remains unclear, however, whether the effects of blue light extend beyond simple alertness processes to also enhance other aspects of cognition, such as memory performance. The aim of this study was to investigate the effects of a thirty minute pulse of blue light versus placebo (amber light) exposure in healthy normally rested individuals in the morning during verbal memory consolidation (i.e., 1.5 hours after memory acquisition) using an abbreviated version of the California Verbal Learning Test (CVLT-II). At delayed recall, individuals who received blue light (n = 12) during the consolidation period showed significantly better long-delay verbal recall than individuals who received amber light exposure (n = 18), while controlling for the effects of general intelligence, depressive symptoms and habitual wake time. These findings extend previous work demonstrating the effect of blue light on brain activation and alertness to further demonstrate its effectiveness at facilitating better memory consolidation and subsequent retention of verbal material. Although preliminary, these findings point to a potential application of blue wavelength light to optimize memory performance in healthy populations. It remains to be determined whether blue light exposure may also enhance performance in clinical populations with memory deficits.

Early versus delayed loading of mandibular implant-supported overdentures: 5-year results.

PubMed

Turkyilmaz, Ilser; Tözüm, Tolga F; Tumer, Celal

2010-05-01

Because of poor retention of complete removable dentures for edentulous patients, implant-supported mandibular overdentures have lately become a popular alternative for them. The aims of this prospective study were to evaluate treatment outcomes of mandibular overdentures supported by two unsplinted early-loaded implants and compare these results with those for delayed-loaded implants. A total of 26 edentulous patients were treated with two unsplinted implants supporting a mandibular overdenture. All implants were placed in the canine regions of each mandible according to the one-stage surgical protocol. There were two groups: test group, in which the overdenture was connected 1 week after surgery, and control group, in which the overdenture was connected 3 months after surgery. Standardized clinical and radiographic parameters were recorded at surgery, and after 3, 6, 12, and 18 months, and 2, 3, 4, and 5 years. No implants were lost, and 0.93 +/- 0.3 mm marginal bone resorption was noted for all implants after 5 years. Clinical implant stability measurements, clinical peri-implant parameters, and marginal bone resorptions showed no statistically significant differences between the two groups over 5 years. The results of this prospective clinical study suggest that there is no significant difference in the clinical and radiographic state of patients treated with implant supported mandibular overdentures loaded either 1 week or 3 months after surgery.

VAPOR-PHASE TRANSPORT OF TRICHLOROETHENE IN AN INTERMEDIATE-SCALE VADOSE-ZONE SYSTEM: RETENTION PROCESSES AND TRACER-BASED PREDICTION

PubMed Central

Costanza-Robinson, Molly S.; Carlson, Tyson D.; Brusseau, Mark L.

2013-01-01

Gas-phase miscible-displacement experiments were conducted using a large weighing lysimeter to evaluate retention processes for volatile organic compounds (VOCs) in water-unsaturated (vadoze-zone) systems, and to test the utility of gas-phase tracers for predicting VOC retardation. Trichloroethene (TCE) served as a model VOC, while trichlorofluoromethane (CFM) and heptane were used as partitioning tracers to independently characterize retention by water and the air-water interface, respectively. Retardation factors for TCE ranged between 1.9 and 3.5, depending on water content. The results indicate that dissolution into the bulk water was the primary retention mechanism for TCE under all conditions studied, contributing approximately two thirds of the total measured retention. Accumulation at the air-water interface comprised a significant fraction of the observed retention for all experiments, with an average contribution of approximately 24%. Sorption to the solid phase contributed approximately 10% to retention. Water contents and air-water interfacial areas estimated based on the CFM and heptane tracer data, respectively, were similar to independently measured values. Retardation factors for TCE predicted using the partitioning-tracer data were in reasonable agreement with the measured values. These results suggest that gas-phase tracer tests hold promise for characterizing the retention and transport of VOCs in the vadose-zone. PMID:23333418

Central ghrelin increases anxiety in the Open Field test and impairs retention memory in a passive avoidance task in neonatal chicks.

PubMed

Carvajal, Pedro; Carlini, Valeria P; Schiöth, Helgi B; de Barioglio, Susana R; Salvatierra, Nancy A

2009-05-01

Ghrelin (Grh) is an endogenous ligand for the growth hormone secretagogue receptor. Although Ghr stimulates feeding in rats, it inhibits feeding in neonatal chicks. However, little is known about other central behavioral effects of Ghr. Therefore, we investigated the Ghr effects, injected intracerebroventricularly, on anxiety and memory retention of neonatal chicks in an Open Field test and in a one-trial passive avoidance task, respectively. In the Open Field test, the administration of Ghr in a dose-dependent manner increased the latency to ambulate but decreased ambulation activity, indicating an anxiogenic effect. Furthermore, chicks trained on a passive avoidance task and injected with a dose of 30pmol of Ghr immediately after training showed an impairment of memory retention. However, there were no significant effects on the number of pecks during the pretraining, training, retention and discrimination. In addition, different doses of Ghr produced an inhibition in food intake at different times after injection. Our results indicate that Ghr induces anxiogenesis in chicks. Moreover, we have shown for the first time that Ghr can decrease memory retention in a non-mammalian species, suggesting that Ghr may play an important role in the processes of memory retention in birds.

75 FR 67233 - Federal Motor Vehicle Safety Standards; Head Restraints

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-02

... backset, backset retention and displacement, height retention, non-use position, definition of rear... backset displacement limits.\\9\\ To address this testing problem, in the May 2007 final rule the agency... ability to be fixated during static testing of head restraint displacement. Expansion of Fixation Option...

Accounting for escape mortality in fisheries: implications for stock productivity and optimal management.

PubMed

Baker, Matthew R; Schindler, Daniel E; Essington, Timothy E; Hilborn, Ray

2014-01-01

Few studies have considered the management implications of mortality to target fish stocks caused by non-retention in commercial harvest gear (escape mortality). We demonstrate the magnitude of this previously unquantified source of mortality and its implications for the population dynamics of exploited stocks, biological metrics, stock productivity, and optimal management. Non-retention in commercial gillnet fisheries for Pacific salmon (Oncorhynchus spp.) is common and often leads to delayed mortality in spawning populations. This represents losses, not only to fishery harvest, but also in future recruitment to exploited stocks. We estimated incidence of non-retention in Alaskan gillnet fisheries for sockeye salmon (O. nerka) and found disentanglement injuries to be extensive and highly variable between years. Injuries related to non-retention were noted in all spawning populations, and incidence of injury ranged from 6% to 44% of escaped salmon across nine river systems over five years. We also demonstrate that non-retention rates strongly correlate with fishing effort. We applied maximum likelihood and Bayesian approaches to stock-recruitment analyses, discounting estimates of spawning salmon to account for fishery-related mortality in escaped fish. Discounting spawning stock estimates as a function of annual fishing effort improved model fits to historical stock-recruitment data in most modeled systems. This suggests the productivity of exploited stocks has been systematically underestimated. It also suggests that indices of fishing effort may be used to predict escape mortality and correct for losses. Our results illustrate how explicitly accounting for collateral effects of fishery extraction may improve estimates of productivity and better inform management metrics derived from estimates of stock-recruitment analyses.

Release from proactive interference in rat spatial working memory.

PubMed

Roberts, William A; MacDonald, Hayden; Brown, Lyn; Macpherson, Krista

2017-09-01

A three-phase procedure was used to produce proactive interference (PI) in one trial on an eight-arm radial maze. Rats were forced to enter four arms for reward on an initial interference phase, to then enter the four remaining arms on a target phase, and to then choose among all eight arms on a retention test, with only the arms not visited in the target phase containing reward. Control trials involved only the target phase and the retention test. Lower accuracy was found on PI trials than on control trials, but performance on PI trials significantly exceeded chance, showing some retention of target memories. Changes in temporal and reward variables between the interference, target, and retention test phases showed release from PI, but changes in context and pattern of arm entry did not. It is suggested that the release from PI paradigm can be used to understand spatial memory encoding in rats and other species.

Divided attention: an undesirable difficulty in memory retention.

PubMed

Gaspelin, Nicholas; Ruthruff, Eric; Pashler, Harold

2013-10-01

How can we improve memory retention? A large body of research has suggested that difficulty encountered during learning, such as when practice sessions are distributed rather than massed, can enhance later memory performance (see R. A. Bjork & E. L. Bjork, 1992). Here, we investigated whether divided attention during retrieval practice can also constitute a desirable difficulty. Following two initial study phases and one test phase with Swahili-English word pairs (e.g., vuvi-snake), we manipulated whether items were tested again under full or divided attention. Two days later, participants were brought back for a final cued-recall test (e.g., vuvi-?). Across three experiments (combined N = 122), we found no evidence that dividing attention while practicing retrieval enhances memory retention. This finding raises the question of why many types of difficulty during practice do improve long-term retention, but dividing attention does not.

Retention time and flow patterns in Lake Marion, South Carolina, 1984

USGS Publications Warehouse

Patterson, G.G.; Harvey, R.M.

1995-01-01

In 1984, six dye tracer tests were made on Lake Marion to determine flow patterns and retention times under conditions of high and low flow. During the high-flow tests, with an average inflow of about 29,000 cubic feet per second, the approximate travel time through the lake for the peak tracer concentration was 14 days. The retention time was about 20 days. During the low-flow tests, with an average inflow of about 9,000 cubic feet per second, the approximate travel time was 41 days, and the retention time was about 60 days. The primary factors controlling movement of water in the lake are lake inflow and outflow. The tracer cloud moved consistently downstream, slowing as the lake widened. Flow patterns in most of the coves, and in some areas along the northeastern shore, are influenced more by tributary inflow than by factors attributable to water from the main body of the lake.

Why Do Rereading Lag Effects Depend on Test Delay?

ERIC Educational Resources Information Center

Rawson, Katherine A.

2012-01-01

In previous research, rereading after a long lag versus a short lag led to greater performance on delayed tests but not on immediate tests. The current study tested two accounts of why the effects of rereading lag depend on test delay. The "levels of representation" ("LOR") "hypothesis" states that the effects reflect…

Dissociation of long-term verbal memory and fronto-executive impairment in first-episode psychosis

PubMed Central

Leeson, V. C.; Robbins, T. W.; Franklin, C.; Harrison, M.; Harrison, I.; Ron, M. A.; Barnes, T. R. E.; Joyce, E. M.

2009-01-01

Background Verbal memory is frequently and severely affected in schizophrenia and has been implicated as a mediator of poor clinical outcome. Whereas encoding deficits are well demonstrated, it is unclear whether retention is impaired. This distinction is important because accelerated forgetting implies impaired consolidation attributable to medial temporal lobe (MTL) dysfunction whereas impaired encoding and retrieval implicates involvement of prefrontal cortex. Method We assessed a group of healthy volunteers (n=97) and pre-morbid IQ- and sex-matched first-episode psychosis patients (n=97), the majority of whom developed schizophrenia. We compared performance of verbal learning and recall with measures of visuospatial working memory, planning and attentional set-shifting, and also current IQ. Results All measures of performance, including verbal memory retention, a memory savings score that accounted for learning impairments, were significantly impaired in the schizophrenia group. The difference between groups for delayed recall remained even after the influence of learning and recall was accounted for. Factor analyses showed that, in patients, all variables except verbal memory retention loaded on a single factor, whereas in controls verbal memory and fronto-executive measures were separable. Conclusions The results suggest that IQ, executive function and verbal learning deficits in schizophrenia may reflect a common abnormality of information processing in prefrontal cortex rather than specific impairments in different cognitive domains. Verbal memory retention impairments, however, may have a different aetiology. PMID:19419594

Spared Anterograde Memory for Shock-Probe Fear Conditioning After Inactivation of the Amygdala

PubMed Central

Lehmann, Hugo; Treit, Dallas; Parent, Marise B.

2003-01-01

Previous studies have shown that amygdala lesions impair avoidance of an electrified probe. This finding has been interpreted as indicating that amygdala lesions reduce fear. It is unclear, however, whether amygdala-lesioned rats learn that the probe is associated with shock. If the lesions prevent the formation of this association, then pretraining reversible inactivation of the amygdala should impair both acquisition and retention performance. To test this hypothesis, the amygdala was inactivated (tetrodotoxin; TTX; 1 ng/side) before a shock-probe acquisition session, and retention was tested 4 d later. The data indicated that, compared with rats infused with vehicle, rats infused with TTX received more shocks during the acquisition session, but more importantly, were not impaired on the retention test. In Experiment 2, we assessed whether the spared memory on the retention test was caused by overtraining during acquisition. We used the same procedure as in Experiment 1, with the exception that the number of shocks the rats received during the acquisition session was limited to four. Again the data indicated that amygdala inactivation did not impair performance on the retention test. These results indicate that amygdala inactivation does not prevent the formation of an association between the shock and the probe and that shock-probe deficits during acquisition likely reflect the amygdala's involvement in other processes. PMID:12888544

Ability and Motivation: Assessing Individual Factors that Contribute to University Retention

ERIC Educational Resources Information Center

Alarcon, Gene M.; Edwards, Jean M.

2013-01-01

The current study explored individual differences in ability and motivation factors of retention in first-year college students. We used discrete-time survival mixture analysis to model university retention. Parents' education, gender, American College Test (ACT) scores, conscientiousness, and trait affectivity were explored as predictors of…

40 CFR 792.195 - Retention of records.

Code of Federal Regulations, 2011 CFR

2011-07-01

... mutagenicity tests, specimens of soil, water, and plants, and wet specimens of blood, urine, feces, biological... 40 Protection of Environment 32 2011-07-01 2011-07-01 false Retention of records. 792.195 Section... ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Records and Reports § 792.195 Retention of records...

40 CFR 792.195 - Retention of records.

Code of Federal Regulations, 2014 CFR

2014-07-01

... mutagenicity tests, specimens of soil, water, and plants, and wet specimens of blood, urine, feces, biological... 40 Protection of Environment 32 2014-07-01 2014-07-01 false Retention of records. 792.195 Section... ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Records and Reports § 792.195 Retention of records...

40 CFR 792.195 - Retention of records.

Code of Federal Regulations, 2012 CFR

2012-07-01

... mutagenicity tests, specimens of soil, water, and plants, and wet specimens of blood, urine, feces, biological... 40 Protection of Environment 33 2012-07-01 2012-07-01 false Retention of records. 792.195 Section... ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Records and Reports § 792.195 Retention of records...

40 CFR 792.195 - Retention of records.

Code of Federal Regulations, 2013 CFR

2013-07-01

... mutagenicity tests, specimens of soil, water, and plants, and wet specimens of blood, urine, feces, biological... 40 Protection of Environment 33 2013-07-01 2013-07-01 false Retention of records. 792.195 Section... ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Records and Reports § 792.195 Retention of records...

40 CFR 80.335 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 17 2013-07-01 2013-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Sampling, Testing and Retention Requirements for Refiners and Importers § 80.335 What gasoline sample...

40 CFR 80.335 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 16 2010-07-01 2010-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Sampling, Testing and Retention Requirements for Refiners and Importers § 80.335 What gasoline sample...

40 CFR 80.335 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 17 2012-07-01 2012-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Sampling, Testing and Retention Requirements for Refiners and Importers § 80.335 What gasoline sample...

40 CFR 80.335 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 17 2014-07-01 2014-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Sampling, Testing and Retention Requirements for Refiners and Importers § 80.335 What gasoline sample...

40 CFR 80.335 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 16 2011-07-01 2011-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Sampling, Testing and Retention Requirements for Refiners and Importers § 80.335 What gasoline sample...

The relationship between vulnerable attachment style, psychopathology, drug abuse, and retention in treatment among methadone maintenance treatment patients.

PubMed

Potik, David; Peles, Einat; Abramsohn, Yahli; Adelson, Miriam; Schreiber, Shaul

2014-01-01

The relationship between vulnerable attachment style, psychopathology, drug abuse, and retention in treatment among patients in methadone maintenance treatment (MMT) was examined by the Vulnerable Attachment Style Questionnaire (VASQ), the Symptom Checklist-90 (SCL-90), and drug abuse urine tests. After six years, retention in treatment and repeated urine test results were studied. Patients with vulnerable attachment style (a high VASQ score) had higher rates of drug abuse and higher psychopathology levels compared to patients with secure attachment style, especially on the interpersonal sensitivity, anxiety, hostility, phobic anxiety, and paranoid ideation scales. Drug abstinence at baseline was related to retention in treatment and to higher rates of drug abstinence after six years in MMT, whereas a vulnerable attachment style could not predict drug abstinence and retention in treatment. Clinical Implications concerning treatment of drug abusing populations and methodological issues concerning the VASQ's subscales are also discussed.

Spherical powder for retaining thermosetting acrylic resin veneers.

PubMed

Tanaka, T; Atsuta, M; Uchiyama, Y; Nakabayashi, N; Masuhara, E

1978-03-01

1. Nine different sizes of spherical powder were prepared, and their effectiveness as retentive devices was evaluated against those available commercially. 2. Smaller-diameter spherical powder (No. 5) gave the best results of all retaining devices tested. 3. The physical properties of the resins play an important role in the retentive strength with No. 5 retention beads. The retentive strength was reduced when brittle resin was used. 4. The retentive strength of the resin veneer was greatly affected by the angle of stress at the incisal resin. The retentive strength increased as the angle between the longitudinal axis of the specimen and the direction of stress decreased.

Blood Pressure Directed Booster Trainings Improve Intensive Care Unit Provider Retention of Excellent Cardiopulmonary Resuscitation Skills.

PubMed

Wolfe, Heather; Maltese, Matthew R; Niles, Dana E; Fischman, Elizabeth; Legkobitova, Veronika; Leffelman, Jessica; Berg, Robert A; Nadkarni, Vinay M; Sutton, Robert M

2015-11-01

Brief, intermittent cardiopulmonary resuscitation (CPR) training sessions, "Booster Trainings," improve CPR skill acquisition and short-term retention. The objective of this study was to incorporate arterial blood pressure (ABP) tracings into Booster Trainings to improve CPR skill retention. We hypothesized that ABP-directed CPR "Booster Trainings" would improve intensive care unit (ICU) provider 3-month retention of excellent CPR skills without need for interval retraining. A CPR manikin creating a realistic relationship between chest compression depth and ABP was used for training/testing. Thirty-six ICU providers were randomized to brief, bedside ABP-directed CPR manikin skill retrainings: (1) Booster Plus (ABP visible during training and testing) versus (2) Booster Alone (ABP visible only during training, not testing) versus (3) control (testing, no intervention). Subjects completed skill tests pretraining (baseline), immediately after training (acquisition), and then retention was assessed at 12 hours, 3 and 6 months. The primary outcome was retention of excellent CPR skills at 3 months. Excellent CPR was defined as systolic blood pressure of 100 mm Hg or higher and compression rate 100 to 120 per minute. Overall, 14 of 24 (58%) participants acquired excellent CPR skills after their initial training (Booster Plus 75% vs 50% Booster Alone, P = 0.21). Adjusted for age, ABP-trained providers were 5.2× more likely to perform excellent CPR after the initial training (95% confidence interval [95% CI], 1.3-21.2; P = 0.02), and to retain these skills at 12 hours (adjusted odds ratio, 4.4; 95% CI, 1.3-14.9; P = 0.018) and 3 months (adjusted odds ratio, 4.1; 95% CI, 1.2-13.9; P = 0.023) when compared to baseline performance. The ABP-directed CPR booster trainings improved ICU provider 3-month retention of excellent CPR skills without the need for interval retraining.

FACTORS INFLUENCING ACQUISITION AND RETENTION OF LEARNING IN VOCATIONAL AGRICULTURE.

ERIC Educational Resources Information Center

CHRISTENSEN, VIRGIL EARL

A PRETEST, POST-TEST, AND RETENTION TEST OF 481 SOPHOMORE STUDENTS ENROLLED IN 33 WISCONSIN HIGH SCHOOLS OFFERING VOCATIONAL AGRICULTURE WERE CONDUCTED TO DETERMINE THE EFFECT OF INDIVIDUAL, HOME-FARM SITUATION, AND STUDENT SUPERVISED FARMING EXPERIENCE DIFFERENCES UPON ACQUIRING AND RETAINING LEARNING IN VOCATIONAL AGRICULTURE CLASSROOMS. EACH…

The effect of testing versus restudy on retention: a meta-analytic review of the testing effect.

PubMed

Rowland, Christopher A

2014-11-01

Engaging in a test over previously studied information can serve as a potent learning event, a phenomenon referred to as the testing effect. Despite a surge of research in the past decade, existing theories have not yet provided a cohesive account of testing phenomena. The present study uses meta-analysis to examine the effects of testing versus restudy on retention. Key results indicate support for the role of effortful processing as a contributor to the testing effect, with initial recall tests yielding larger testing benefits than recognition tests. Limited support was found for existing theoretical accounts attributing the testing effect to enhanced semantic elaboration, indicating that consideration of alternative mechanisms is warranted in explaining testing effects. Future theoretical accounts of the testing effect may benefit from consideration of episodic and contextually derived contributions to retention resulting from memory retrieval. Additionally, the bifurcation model of the testing effect is considered as a viable framework from which to characterize the patterns of results present across the literature. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Why the Wait? Delayed HIV Diagnosis among Men Who Have Sex with Men

PubMed Central

Thiede, Hanne; Hawes, Stephen E.; Golden, Matthew R.; Hutcheson, Rebecca; Carey, James W.; Kurth, Ann; Jenkins, Richard A.

2010-01-01

We sought to identify factors associated with delayed diagnosis of human immunodeficiency virus (HIV; testing HIV-seropositive 6 months or more after HIV seroconversion), by comparing delayed testers to non-delayed testers (persons who were diagnosed within 6 months of HIV seroconversion), in King County, Washington among men who have sex with men (MSM). Participants were recruited from HIV testing sites in the Seattle area. Delayed testing status was determined by the Serologic Testing Algorithm for Recent HIV Seroconversion or a self-reported previous HIV-negative test. Quantitative data on sociodemographic characteristics, health history, and drug-use and sexual behaviors were collected via computer-assisted self-interviews. Qualitative semi-structured interviews regarding testing and risk behaviors were also conducted. Multivariate analysis was used to identify factors associated with delayed diagnosis. Content analysis was used to establish themes in the qualitative data. Out of the 77 HIV-seropositive MSM in this sample, 39 (51%) had evidence of delayed diagnosis. Factors associated with delayed testing included being African-American, homeless, “out” to 50% or less people about male-male sex, and having only one sex partner in the past 6 months. Delayed testers often cited HIV-related sickness as their reason for testing and fear and wanting to be in denial of their HIV status as reasons for not testing. Delayed testers frequently did not identify as part of the MSM community, did not recognize that they were at risk for HIV acquisition, and did not feel a responsibility to themselves or others to disclose their HIV status. This study illustrates the need to further explore circumstances around delayed diagnosis in MSM and develop outreach methods and prevention messages targeted specifically to this potentially highly marginalized population in order to detect HIV infections earlier, provide HIV care, and prevent new infections. PMID:20186493

Better Working Memory and Motor Inhibition in Children Who Delayed Gratification

PubMed Central

Yu, Junhong; Kam, Chi-Ming; Lee, Tatia M. C.

2016-01-01

Background: Despite the extensive research on delayed gratification over the past few decades, the neurocognitive processes that subserve delayed gratification remains unclear. As an exploratory step in studying these processes, the present study aims to describe the executive function profiles of children who were successful at delaying gratification and those who were not. Methods: A total of 138 kindergarten students (65 males, 73 females; Mage = 44 months, SD = 3.5; age range = 37–53 months) were administered a delayed gratification task, a 1-back test, a Day/night Stroop test and a Go/no-go test. The outcome measures of these tests were then analyzed between groups using a Multivariate Analysis of Variance, and subsequently a Multivariate Analysis of Covariance incorporating age as a covariate. Results: Children who were successful in delaying gratification were significantly older and had significantly better outcomes in the 1-back test and go/no-go test. With the exception of the number of hits in the go/no-go test, all other group differences remained significant after controlling for age. Conclusion: Children who were successful in delaying gratification showed better working memory and motor inhibition relative to those who failed the delayed gratification task. The implications of these findings are discussed. PMID:27493638

Delayed post-harvest ripening-associated changes in Manilkara zapota L. var. Kalipatti with composite edible coating.

PubMed

Vishwasrao, Chandrahas; Ananthanarayan, Laxmi

2017-01-01

There has been limited research on extending the shelf-life of sapota (Manilkara zapota L. var. Kalipatti) fruit. An edible coating made up of methyl cellulose (MC) and palm oil (PO) was applied to study the extension in shelf-life. Changes in physical and chemical properties of fruit were studied along with peroxidase (POD), polyphenol oxidase (PPO) and pectin methylesterase (PME) activities during post-harvest ripening of sapota. The fruits coated with 15 g L -1 MC and 11.25 g L -1 PO showed significant (P < 0.05) delay in physiological weight loss, decrease in fruit firmness losses as well as slower fruit darkening. The coating on the fruits resulted in better retention of ascorbic acid, delayed the loss of total phenolic content, and delayed the increase in total soluble solids and total reducing sugars as compared to control fruits. The coating either delayed or reduced the enzyme activities of POD, PPO and PME of the fruit. The results suggest that edible coating made up of MC-PO has potential to maintain the quality of sapota fruit. The edible coating extended the shelf-life of sapota fruit by 3 days preserving fruit quality up to 7 days at 24 ± 1 °C and 65 ± 5 %RH. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Sleep deprivation accelerates delay-related loss of visual short-term memories without affecting precision.

PubMed

Wee, Natalie; Asplund, Christopher L; Chee, Michael W L

2013-06-01

Visual short-term memory (VSTM) is an important measure of information processing capacity and supports many higher-order cognitive processes. We examined how sleep deprivation (SD) and maintenance duration interact to influence the number and precision of items in VSTM using an experimental design that limits the contribution of lapses at encoding. For each trial, participants attempted to maintain the location and color of three stimuli over a delay. After a retention interval of either 1 or 10 seconds, participants reported the color of the item at the cued location by selecting it on a color wheel. The probability of reporting the probed item, the precision of report, and the probability of reporting a nonprobed item were determined using a mixture-modeling analysis. Participants were studied twice in counterbalanced order, once after a night of normal sleep and once following a night of sleep deprivation. Sleep laboratory. Nineteen healthy college age volunteers (seven females) with regular sleep patterns. Approximately 24 hours of total SD. SD selectively reduced the number of integrated representations that can be retrieved after a delay, while leaving the precision of object information in the stored representations intact. Delay interacted with SD to lower the rate of successful recall. Visual short-term memory is compromised during sleep deprivation, an effect compounded by delay. However, when memories are retrieved, they tend to be intact.

Digital versus conventional techniques for pattern fabrication of implant-supported frameworks

PubMed Central

Alikhasi, Marzieh; Rohanian, Ahmad; Ghodsi, Safoura; Kolde, Amin Mohammadpour

2018-01-01

Objective: The aim of this experimental study was to compare retention of frameworks cast from wax patterns fabricated by three different methods. Materials and Methods: Thirty-six implant analogs connected to one-piece abutments were divided randomly into three groups according to the wax pattern fabrication method (n = 12). Computer-aided design/computer-aided manufacturing (CAD/CAM) milling machine, three-dimensional printer, and conventional technique were used for fabrication of waxing patterns. All laboratory procedures were performed by an expert-reliable technician to eliminate intra-operator bias. The wax patterns were cast, finished, and seated on related abutment analogs. The number of adjustment times was recorded and analyzed by Kruskal–Wallis test. Frameworks were cemented on the corresponding analogs with zinc phosphate cement and tensile resistance test was used to measure retention value. Statistical Analysis Used: One-way analysis of variance (ANOVA) and post hoc Tukey tests were used for statistical analysis. Level of significance was set at P < 0.05. Results: The mean retentive values of 680.36 ± 21.93 N, 440.48 ± 85.98 N, and 407.23 ± 67.48 N were recorded for CAD/CAM, rapid prototyping, and conventional group, respectively. One-way ANOVA test revealed significant differences among the three groups (P < 0.001). The post hoc Tukey test showed significantly higher retention for CAD/CAM group (P < 0.001), while there was no significant difference between the two other groups (P = 0.54). CAD/CAM group required significantly more adjustments (P < 0.001). Conclusions: CAD/CAM-fabricated wax patterns showed significantly higher retention for implant-supported cement-retained frameworks; this could be a valuable help when there are limitations in the retention of single-unit implant restorations. PMID:29657528

Digital versus conventional techniques for pattern fabrication of implant-supported frameworks.

PubMed

Alikhasi, Marzieh; Rohanian, Ahmad; Ghodsi, Safoura; Kolde, Amin Mohammadpour

2018-01-01

The aim of this experimental study was to compare retention of frameworks cast from wax patterns fabricated by three different methods. Thirty-six implant analogs connected to one-piece abutments were divided randomly into three groups according to the wax pattern fabrication method ( n = 12). Computer-aided design/computer-aided manufacturing (CAD/CAM) milling machine, three-dimensional printer, and conventional technique were used for fabrication of waxing patterns. All laboratory procedures were performed by an expert-reliable technician to eliminate intra-operator bias. The wax patterns were cast, finished, and seated on related abutment analogs. The number of adjustment times was recorded and analyzed by Kruskal-Wallis test. Frameworks were cemented on the corresponding analogs with zinc phosphate cement and tensile resistance test was used to measure retention value. One-way analysis of variance (ANOVA) and post hoc Tukey tests were used for statistical analysis. Level of significance was set at P < 0.05. The mean retentive values of 680.36 ± 21.93 N, 440.48 ± 85.98 N, and 407.23 ± 67.48 N were recorded for CAD/CAM, rapid prototyping, and conventional group, respectively. One-way ANOVA test revealed significant differences among the three groups ( P < 0.001). The post hoc Tukey test showed significantly higher retention for CAD/CAM group ( P < 0.001), while there was no significant difference between the two other groups ( P = 0.54). CAD/CAM group required significantly more adjustments ( P < 0.001). CAD/CAM-fabricated wax patterns showed significantly higher retention for implant-supported cement-retained frameworks; this could be a valuable help when there are limitations in the retention of single-unit implant restorations.

Retention of mandibular advancement devices in the treatment of obstructive sleep apnea: an in vitro pilot study.

PubMed

Vanderveken, Olivier M; Van de Heyning, Paul; Braem, Marc J

2014-05-01

In order for a mandibular advancement device (MAD) to be efficacious, it must remain seated on the teeth during sleep. Quantitative data on the retentive characteristics of MADs are currently unavailable. The present pilot study is the first to describe an in vitro setup testing the retentive characteristics of different monobloc MADs. A hydraulic cyclic test machine was used with MADs seated on dental casts to measure retention forces upon removal of the MADs. A custom-made monobloc (CM-mono), a thermoplastic monobloc (TP-mono), and a thermoplastic duobloc (TP-duo) configured as a monobloc were tested. Two protrusions were investigated, representing 25 and 65% of the maximal protrusion. The effects of the type of MAD, duration of the test, and amount of protrusion on removal forces were measured. The measured removal forces of all three MADs tested differed significantly, with the TP-duo showing the highest values (P < 0.0001). The effects of wear due to the repetitive cyclic loading became obvious by the production of wear particles in all MADs tested. However, only the TP-duo showed a significant reduction in time in removal forces for both protrusion positions (P < 0.0001; P = 0.0011). The effect of the amount of protrusion on the removal forces differed significantly between all three MADs tested (P = 0.0074). This in vitro pilot study reveals significant differences in retention forces for the MADs tested. The findings are consistent with clinical effects of nightly loss of MADs as reported in the literature and are within the range of reported physiological mouth-opening forces. Future research is needed to determine the key design features of MADs that explain these differences.

[Biological effects of artificial mineral fibers].

PubMed

Woźniak, H

1989-01-01

The present review paper was prepared on the basis of 52 source-books devoted to experimental investigations. Principal conclusions emerging from the experiments described in the references quoted are as follows. MMMF retention in alveoli is conditioned mainly by the fibres size--for fibres of constant dimater retention increases proportionally to their length, while long and thin fibres undergo degradation in fluids much more easily than the short and thick ones. Fibrous effect of glass fibres and glass wool is less remarkable than that of chrysotile and crocidolite; after exposure to glass fibre and wool has stopped, no progress of fibrous changes in animals was observed. In animals exposed to grass fibre or mineral wool through inhalation, the increase in cancer rate was not statistically significant; glass fibres introduced into the pleura showed a weaker tendency to induce neoplasms than the same amount of asbestos fibres, while basalt and ceramic wool induced reaction similar to that provoked by asbestos. In the case of combined exposure glass fibres intensified the toxic effect of styrene in mice and enhanced the incidence of lung cancer in rats exposed to radon. In in vitro study the destructive effect represented the distribution function of fibres size--long fibres (less than 10 microns) and thin fibres (less than 1 micron diameter) demonstrated stronger toxic effect. Glass fibres provoked neither mutations in bacterial test, nor sister chromatid exchange in animal cells in vitro. However, they caused mitosis delay and structural changes in chromosomes.

A model stomach system to investigate disintegration kinetics of solid foods during gastric digestion.

PubMed

Kong, F; Singh, R P

2008-06-01

Knowledge of the disintegration kinetics of food particulates in the human stomach is essential for assessing the bioaccessibility of nutrients in solid foods and understanding stomach emptying. The objective of this study was to develop a model stomach system and to investigate the kinetics of food disintegration. Our system consisted mainly of a turntable and a jacketed glass chamber containing simulated gastric juice in which plastic beads were added to simulate food particulates as well as provide a suitable mechanical destructive force on food samples. The mechanical force on the samples was simultaneously measured using the load cell of a TA-XT2 texture analyzer. Cylindrical carrots and ham samples were used as representative foods. The system is capable of simulating the in vivo stomach in terms of providing a wide range of continuous and periodic forces comparable to those measured in vivo. The modified power exponential function of the form y(t)= 1 - (1 -e(-kt))(beta), where y(t) is the mass retention ratio at time t, provided a reasonable description for the disintegration performance of tested foods. The mass retention curve can be either a sigmoidal decay with an initial delay or an exponential decay, which are decided largely by the hardness of the foods during digestion and the extent of physical force acting on the foods. A good match was observed between the kinetics of food disintegration and in vivo stomach emptying.

Learning and retention through predictive inference and classification.

PubMed

Sakamoto, Yasuaki; Love, Bradley C

2010-12-01

Work in category learning addresses how humans acquire knowledge and, thus, should inform classroom practices. In two experiments, we apply and evaluate intuitions garnered from laboratory-based research in category learning to learning tasks situated in an educational context. In Experiment 1, learning through predictive inference and classification were compared for fifth-grade students using class-related materials. Making inferences about properties of category members and receiving feedback led to the acquisition of both queried (i.e., tested) properties and nonqueried properties that were correlated with a queried property (e.g., even if not queried, students learned about a species' habitat because it correlated with a queried property, like the species' size). In contrast, classifying items according to their species and receiving feedback led to knowledge of only the property most diagnostic of category membership. After multiple-day delay, the fifth-graders who learned through inference selectively retained information about the queried properties, and the fifth-graders who learned through classification retained information about the diagnostic property, indicating a role for explicit evaluation in establishing memories. Overall, inference learning resulted in fewer errors, better retention, and more liking of the categories than did classification learning. Experiment 2 revealed that querying a property only a few times was enough to manifest the full benefits of inference learning in undergraduate students. These results suggest that classroom teaching should emphasize reasoning from the category to multiple properties rather than from a set of properties to the category. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

Assessment of the Effects of Problem Solving Instructional Strategies on Students' Achievement and Retention in Chemistry with Respect to Location in Rivers State

ERIC Educational Resources Information Center

Nbina, Jacobson Barineka; Obomanu, B. Joseph

2011-01-01

We report a study focused on how problem-solving instructional strategies would affect students' achievement and retention in Chemistry with particular reference to River State. A pre-test, post-test, non-equivalent control group design was adopted. Two research questions and two hypotheses were respectively answered and tested. Purposive and…

Altered behavior in experimental cortical dysplasia.

PubMed

Zhou, Fu-Wen; Rani, Asha; Martinez-Diaz, Hildabelis; Foster, Thomas C; Roper, Steven N

2011-12-01

Developmental delay and cognitive impairment are common comorbidities in people with epilepsy associated with malformations of cortical development (MCDs). We studied cognition and behavior in an animal model of diffuse cortical dysplasia (CD), in utero irradiation, using a battery of behavioral tests for neuromuscular and cognitive function. Fetal rats were exposed to 2.25 Gy external radiation on embryonic day 17 (E17). At 1 month of age they were tested using an open field task, a grip strength task, a grid walk task, inhibitory avoidance, an object recognition task, and the Morris water maze task. Rats with CD showed reduced nonlocomotor activity in the open field task and impaired motor coordination for grid walking but normal grip strength. They showed a reduced tendency to recognize novel objects and reduced retention in an inhibitory avoidance task. Water maze testing showed that learning and memory were impaired in irradiated rats for both cue discrimination and spatially oriented tasks. These results demonstrate significant deficits in cortex- and hippocampus-dependent cognitive functions associated with the diffuse abnormalities of cortical and hippocampal development that have been documented in this model. This study documents multimodal cognitive deficits associated with CD and can serve as the foundation for future investigations into the mechanisms of and possible therapeutic interventions for this problem. Wiley Periodicals, Inc. © 2011 International League Against Epilepsy.

Middle School Students' Mathematics Knowledge Retention: Online or Face-To-Face Environments

ERIC Educational Resources Information Center

Edwards, Clayton M.; Rule, Audrey C.; Boody, Robert M.

2017-01-01

Educators seek to develop students' mathematical knowledge retention to increase student efficacy in follow-on classwork, improvement of test scores, attainment of standards, and preparation for careers. Interactive visuals, feedback during problem solving, and incorporation of higher-order thinking skills are known to increase retention, but a…

7 CFR 800.147 - Maintenance and retention of records on delegations, designations, contracts, and approval of...

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 7 2010-01-01 2010-01-01 false Maintenance and retention of records on delegations, designations, contracts, and approval of scale testing organizations. 800.147 Section 800.147 Agriculture... and Forms (general) § 800.147 Maintenance and retention of records on delegations, designations...

The Road to Redemption: Reclaiming the Value in Assessment Retention Exams

ERIC Educational Resources Information Center

Stohlman, Trey

2015-01-01

A good assessment plan combines many direct and indirect measures to validate the collected data. One often controversial assessment measure comes in the form of retention exams. Although assessment retention exams may come with faults, others advocate for their inclusion in program assessment. Objective-based tests may offer insight to…

Please, Not Another Push to Get Tough on Student Retention

ERIC Educational Resources Information Center

Norton, M. Scott

2011-01-01

Standardized academic testing, under-performing schools, demands for high standards in America's schools and current levels of student dropouts have resulted in renewed calls for "getting tough on student retention." The push for student retention is demanded by school boards and others in spite of the overwhelming research evidence that…

Preload evaluation of different screws in external hexagon joint.

PubMed

Assunção, Wirley Gonçalves; Delben, Juliana Aparecida; Tabata, Lucas Fernando; Barão, Valentim Adelino Ricardo; Gomes, Erica Alves; Garcia, Idelmo Rangel

2012-02-01

This study compared the maintenance of tightening torque in different retention screw types of implant-supported crowns. Twelve metallic crowns in UCLA abutments cast with cobalt-chromium alloy were attached to external hexagon osseointegrated implants with different retention screws: group A: titanium alloy retention screw; group B: gold alloy retention screw with gold coating; group C: titanium alloy retention screw with diamond-like carbon film coating; and group D: titanium alloy retention screw with aluminum titanium nitride coating. Three detorque measurements were obtained after torque insertion in each replica. Data were evaluated by analysis of variance (ANOVA), Tukey's test (P < 0.05), and t test (P < 0.05). Detorque value reduced in all groups (P < 0.05). Group A retained the highest percentage of torque in comparison with the other groups (P < 0.05). Groups B and D retained the lowest percentage of torque without statistically significant difference between them (P > 0.05). All screw types exhibited reduction in the detorque value. The titanium screw maintained the highest percentage of torque whereas the gold-coated screw and the titanium screw with aluminum titanium nitride coating retained the lowest percentage.

Metamorphological awareness and EFL students' memory, retention, and retrieval of English adjectival lexicons.

PubMed

Zhang, Lawrence Jun

2002-12-01

Research has shown that foreign or second language learners' metalinguistic awareness has important effects on their acquisition of the target language. Important among a multitude of the concerns are problems these learners encounter when they have to process the morphological features of individual words, particularly in the acquisition of literacy skills. Nevertheless, for students who learn English as a foreign or second language for academic purposes, one of the biggest challenges in their advanced study is how they can effectively remember, retain, and retrieve the colossal number of newly learnt English vocabulary, including adjectival lexicons, to enhance their academic success. Results from the present report on the effects of metamorphological awareness of 65 adult Chinese EFL learners' memory, retention, and retrieval of adjectival lexicons show that, although the subjects in the two groups did not differ significantly in their performance on a pretest designed to check their lexical knowledge and no sex difference was observed, statistically significant differences were found between the two groups in both conditions (immediate and delayed retrievals) on a posttest. The experimental group and women predominantly performed better in the memory-retention-retrieval tasks assigned to them. Implications for educational research and practices are also discussed.

Structural Barriers to Antiretroviral Therapy Among Sex Workers Living with HIV: Findings of a Longitudinal Study in Vancouver, Canada

PubMed Central

Goldenberg, Shira M.; Montaner, Julio; Duff, Putu; Nguyen, Paul; Dobrer, Sabina; Guillemi, Silvia; Shannon, Kate

2015-01-01

In light of limited data on structural determinants of access and retention in antiretroviral therapy (ART) among sex workers, we examined structural correlates of ART use among sex workers living with HIV over time. Longitudinal data were drawn from a cohort of 646 female sex workers in Vancouver, Canada (2010–2012) and linked pharmacy records on ART dispensation. We used logistic regression with generalized estimating equations (GEE) to examine correlates of gaps in ART use (i.e., treatment interruptions or delayed ART initiation), among sex workers living with HIV (n=74). Over a 2.5-year period, 37.8% of participants experienced gaps in ART use (i.e., no ART dispensed in a six-month period). In a multivariable GEE model, younger age, migration/mobility, incarceration, and non-injection drug use independently correlated with gaps in ART use. In spite of successes scaling-up ART in British Columbia, younger, mobile, or incarcerated sex workers face persistent gaps in access and retention irrespective of drug use. Community-based, tailored interventions to scale-up entry and retention in ART for sex workers should be further explored in this setting. PMID:26148850

Structural Barriers to Antiretroviral Therapy Among Sex Workers Living with HIV: Findings of a Longitudinal Study in Vancouver, Canada.

PubMed

Goldenberg, Shira M; Montaner, Julio; Duff, Putu; Nguyen, Paul; Dobrer, Sabina; Guillemi, Silvia; Shannon, Kate

2016-05-01

In light of limited data on structural determinants of access and retention in antiretroviral therapy (ART) among sex workers, we examined structural correlates of ART use among sex workers living with HIV over time. Longitudinal data were drawn from a cohort of 646 female sex workers in Vancouver, Canada (2010-2012) and linked pharmacy records on ART dispensation. We used logistic regression with generalized estimating equations (GEE) to examine correlates of gaps in ART use (i.e., treatment interruptions or delayed ART initiation), among HIV seropositive participants (n = 74). Over a 2.5-year period, 37.8 % of participants experienced gaps in ART use (i.e., no ART dispensed in a 6-month period). In a multivariable GEE model, younger age, migration/mobility, incarceration, and non-injection drug use independently correlated with gaps in ART use. In spite of successes scaling-up ART in British Columbia, younger, mobile, or incarcerated sex workers face persistent gaps in access and retention irrespective of drug use. Community-based, tailored interventions to scale-up entry and retention in ART for sex workers should be further explored in this setting.

Event models and the fan effect.

PubMed

Radvansky, G A; O'Rear, Andrea E; Fisher, Jerry S

2017-08-01

The current study explored the persistence of event model organizations and how this influences the experience of interference during retrieval. People in this study memorized lists of sentences about objects in locations, such as "The potted palm is in the hotel." Previous work has shown that such information can either be stored in separate event models, thereby producing retrieval interference, or integrated into common event models, thereby eliminating retrieval interference. Unlike prior studies, the current work explored the impact of forgetting up to 2 weeks later on this pattern of performance. We explored three possible outcomes across the various retention intervals. First, consistent with research showing that longer delays reduce proactive and retroactive interference, any retrieval interference effects of competing event models could be reduced over time. Second, the binding of information into events models may weaken over time, causing interference effects to emerge when they had previously been absent. Third, and finally, the organization of information into event models could remain stable over long periods of time. The results reported here are most consistent with the last outcome. While there were some minor variations across the various retention intervals, the basic pattern of event model organization remained preserved over the two-week retention period.

One-Piece Implant-Retained Mandibular Overdentures By Pre-Fabricated Titanium Telescopic Attachments and Frictional Varnish: A Two-Year Prospective Study.

PubMed

Nik, Shahram Namjoy; Nejatian, Touraj

2016-12-01

Clinical efficiency of one-piece screw-type implants with telescopic were attachments evaluated in this study. Twenty-four patients received a mandibular implant-supported overdenture and maxillary complete denture. Ninety-six one-piece implants were inserted in the inter-foraminal area. Implants were immediately loaded with an implant-retained overdenture and telescopic attachments which had frictional retention elements. There was 0.25±0.24 mm, 0.32±0.25 mm, 0.43±0.30 mm, 0.61±0.30 mm and of bone resorption after 3, 6, 12 and 24 months, respectively. The need to activate the frictional retention was the most common complication. Treatment outcomes for prefabricated telescopic retained overdentures on one-piece implants are similar to that obtained in cases of delayed loading. Copyright© 2016 Dennis Barber Ltd.

Does working memory load facilitate target detection?

PubMed

Fruchtman-Steinbok, Tom; Kessler, Yoav

2016-02-01

Previous studies demonstrated that increasing working memory (WM) load delays performance of a concurrent task, by distracting attention and thus interfering with encoding and maintenance processes. The present study used a version of the change detection task with a target detection requirement during the retention interval. In contrast to the above prediction, target detection was faster following a larger set-size, specifically when presented shortly after the memory array (up to 400 ms). The effect of set-size on target detection was also evident when no memory retention was required. The set-size effect was also found using different modalities. Moreover, it was only observed when the memory array was presented simultaneously, but not sequentially. These results were explained by increased phasic alertness exerted by the larger visual display. The present study offers new evidence of ongoing attentional processes in the commonly-used change detection paradigm. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of activation and blockade of NMDA receptors on the extinction of a conditioned passive avoidance response in mice with different levels of anxiety.

PubMed

Tomilenko, R A; Dubrovina, N I

2007-06-01

The effects of an agonist (D-cycloserine) and an antagonist (dizocilpine) of N-methyl-D-aspartate (NMDA) receptors on the learning and extinction of a conditioned passive avoidance response were studied in mice with low, intermediate, and high levels of anxiety. In intermediate-anxiety mice, D-cycloserine (30 mg/kg) had no effect on learning but accelerated extinction, while dizocilpine (0.15 mg/kg) degraded acquisition of the reflex but delayed extinction. In high-anxiety mice, with good learning and no extinction, D-cycloserine had no effect, while dizocilpine decreased learning and facilitated retention of performance of the memory trace at the ongoing level in conditions promoting extinction. In low-anxiety mice, D-cycloserine degraded learning and accelerated extinction, while dizocilpine completely blocked learning and the retention of the passive avoidance response.

Boosting Long-Term Memory via Wakeful Rest: Intentional Rehearsal Is Not Necessary, Consolidation Is Sufficient

PubMed Central

Dewar, Michaela; Alber, Jessica; Cowan, Nelson; Della Sala, Sergio

2014-01-01

People perform better on tests of delayed free recall if learning is followed immediately by a short wakeful rest than by a short period of sensory stimulation. Animal and human work suggests that wakeful resting provides optimal conditions for the consolidation of recently acquired memories. However, an alternative account cannot be ruled out, namely that wakeful resting provides optimal conditions for intentional rehearsal of recently acquired memories, thus driving superior memory. Here we utilised non-recallable words to examine whether wakeful rest boosts long-term memory, even when new memories could not be rehearsed intentionally during the wakeful rest delay. The probing of non-recallable words requires a recognition paradigm. Therefore, we first established, via Experiment 1, that the rest-induced boost in memory observed via free recall can be replicated in a recognition paradigm, using concrete nouns. In Experiment 2, participants heard 30 non-recallable non-words, presented as ‘foreign names in a bridge club abroad’ and then either rested wakefully or played a visual spot-the-difference game for 10 minutes. Retention was probed via recognition at two time points, 15 minutes and 7 days after presentation. As in Experiment 1, wakeful rest boosted recognition significantly, and this boost was maintained for at least 7 days. Our results indicate that the enhancement of memory via wakeful rest is not dependent upon intentional rehearsal of learned material during the rest period. We thus conclude that consolidation is sufficient for this rest-induced memory boost to emerge. We propose that wakeful resting allows for superior memory consolidation, resulting in stronger and/or more veridical representations of experienced events which can be detected via tests of free recall and recognition. PMID:25333957