Limitless capacity: A dynamic object-oriented approach to short-term memory

Directory of Open Access Journals (Sweden)

Bill eMacken

2015-03-01

Full Text Available The notion of capacity-limited processing systems is a core element of cognitive accounts of limited and variable performance, enshrined within the short-term memory construct. We begin with a detailed critical analysis of the conceptual bases of this view and argue that there are fundamental problems – ones that go to the heart of cognitivism more generally – that render it untenable. In place of limited capacity systems, we propose a framework for explaining performance that focuses on the dynamic interplay of three aspects of any given setting: the particular task that must be accomplished, the nature and form of the material upon which the task must be performed, and the repertoire of skills and perceptual-motor functions possessed by the participant. We provide empirical examples of the applications of this framework in areas of performance typically accounted for by reference to capacity-limited short-term memory processes.

How high is visual short-term memory capacity for object layout?

Science.gov (United States)

Sanocki, Thomas; Sellers, Eric; Mittelstadt, Jeff; Sulman, Noah

2010-05-01

Previous research measuring visual short-term memory (VSTM) suggests that the capacity for representing the layout of objects is fairly high. In four experiments, we further explored the capacity of VSTM for layout of objects, using the change detection method. In Experiment 1, participants retained most of the elements in displays of 4 to 8 elements. In Experiments 2 and 3, with up to 20 elements, participants retained many of them, reaching a capacity of 13.4 stimulus elements. In Experiment 4, participants retained much of a complex naturalistic scene. In most cases, increasing display size caused only modest reductions in performance, consistent with the idea of configural, variable-resolution grouping. The results indicate that participants can retain a substantial amount of scene layout information (objects and locations) in short-term memory. We propose that this is a case of remote visual understanding, where observers' ability to integrate information from a scene is paramount.

Neural activity in the hippocampus predicts individual visual short-term memory capacity.

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von Allmen, David Yoh; Wurmitzer, Karoline; Martin, Ernst; Klaver, Peter

2013-07-01

Although the hippocampus had been traditionally thought to be exclusively involved in long-term memory, recent studies raised controversial explanations why hippocampal activity emerged during short-term memory tasks. For example, it has been argued that long-term memory processes might contribute to performance within a short-term memory paradigm when memory capacity has been exceeded. It is still unclear, though, whether neural activity in the hippocampus predicts visual short-term memory (VSTM) performance. To investigate this question, we measured BOLD activity in 21 healthy adults (age range 19-27 yr, nine males) while they performed a match-to-sample task requiring processing of object-location associations (delay period  =  900 ms; set size conditions 1, 2, 4, and 6). Based on individual memory capacity (estimated by Cowan's K-formula), two performance groups were formed (high and low performers). Within whole brain analyses, we found a robust main effect of "set size" in the posterior parietal cortex (PPC). In line with a "set size × group" interaction in the hippocampus, a subsequent Finite Impulse Response (FIR) analysis revealed divergent hippocampal activation patterns between performance groups: Low performers (mean capacity  =  3.63) elicited increased neural activity at set size two, followed by a drop in activity at set sizes four and six, whereas high performers (mean capacity  =  5.19) showed an incremental activity increase with larger set size (maximal activation at set size six). Our data demonstrated that performance-related neural activity in the hippocampus emerged below capacity limit. In conclusion, we suggest that hippocampal activity reflected successful processing of object-location associations in VSTM. Neural activity in the PPC might have been involved in attentional updating. Copyright © 2013 Wiley Periodicals, Inc.

Discrete capacity limits and neuroanatomical correlates of visual short-term memory for objects and spatial locations.

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Konstantinou, Nikos; Constantinidou, Fofi; Kanai, Ryota

2017-02-01

Working memory is responsible for keeping information in mind when it is no longer in view, linking perception with higher cognitive functions. Despite such crucial role, short-term maintenance of visual information is severely limited. Research suggests that capacity limits in visual short-term memory (VSTM) are correlated with sustained activity in distinct brain areas. Here, we investigated whether variability in the structure of the brain is reflected in individual differences of behavioral capacity estimates for spatial and object VSTM. Behavioral capacity estimates were calculated separately for spatial and object information using a novel adaptive staircase procedure and were found to be unrelated, supporting domain-specific VSTM capacity limits. Voxel-based morphometry (VBM) analyses revealed dissociable neuroanatomical correlates of spatial versus object VSTM. Interindividual variability in spatial VSTM was reflected in the gray matter density of the inferior parietal lobule. In contrast, object VSTM was reflected in the gray matter density of the left insula. These dissociable findings highlight the importance of considering domain-specific estimates of VSTM capacity and point to the crucial brain regions that limit VSTM capacity for different types of visual information. Hum Brain Mapp 38:767-778, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Short-term optimal wind power generation capacity in liberalized electricity markets

International Nuclear Information System (INIS)

Olsina, Fernando; Roescher, Mark; Larisson, Carlos; Garces, Francisco

2007-01-01

Mainly because of environmental concerns and fuel price uncertainties, considerable amounts of wind-based generation capacity are being added to some deregulated power systems. The rapid wind development registered in some countries has essentially been driven by strong subsidizing programs. Since wind investments are commonly isolated from market signals, installed wind capacity can be higher than optimal, leading to distortions of the power prices with a consequent loss of social welfare. In this work, the influence of wind generation on power prices in the framework of a liberalized electricity market has been assessed by means of stochastic simulation techniques. The developed methodology allows investigating the maximal wind capacity that would be profitably deployed if wind investments were subject to market conditions only. For this purpose, stochastic variables determining power prices are accurately modeled. A test system resembling the size and characteristics of the German power system has been selected for this study. The expected value of the optimal, short-term wind capacity is evaluated for a considerable number of random realizations of power prices. The impact of dispersing the wind capacity over statistical independent wind sites has also been evaluated. The simulation results reveal that fuel prices, installation and financing costs of wind investments are very influential parameters on the maximal wind capacity that might be accommodated in a market-based manner

Short-term and working memory impairments in aphasia.

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Potagas, Constantin; Kasselimis, Dimitrios; Evdokimidis, Ioannis

2011-08-01

The aim of the present study is to investigate short-term memory and working memory deficits in aphasics in relation to the severity of their language impairment. Fifty-eight aphasic patients participated in this study. Based on language assessment, an aphasia score was calculated for each patient. Memory was assessed in two modalities, verbal and spatial. Mean scores for all memory tasks were lower than normal. Aphasia score was significantly correlated with performance on all memory tasks. Correlation coefficients for short-term memory and working memory were approximately of the same magnitude. According to our findings, severity of aphasia is related with both verbal and spatial memory deficits. Moreover, while aphasia score correlated with lower scores in both short-term memory and working memory tasks, the lack of substantial difference between corresponding correlation coefficients suggests a possible primary deficit in information retention rather than impairment in working memory. Copyright © 2011 Elsevier Ltd. All rights reserved.

Magnetic stimulation of the dorsolateral prefrontal cortex dissociates fragile visual short-term memory from visual working memory

NARCIS (Netherlands)

Sligte, I.G.; Wokke, M.E.; Tesselaar, J.P.; Scholte, H.S.; Lamme, V.A.F.

2011-01-01

To guide our behavior in successful ways, we often need to rely on information that is no longer in view, but maintained in visual short-term memory (VSTM). While VSTM is usually broken down into iconic memory (brief and high-capacity store) and visual working memory (sustained, yet limited-capacity

The contribution of short-term memory capacity to reading ability in adolescents with cochlear implants.

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Edwards, Lindsey; Aitkenhead, Lynne; Langdon, Dawn

2016-11-01

This study aimed to establish the relationship between short-term memory capacity and reading skills in adolescents with cochlear implants. A between-groups design compared a group of young people with cochlear implants with a group of hearing peers on measures of reading, and auditory and visual short-term memory capacity. The groups were matched for non-verbal IQ and age. The adolescents with cochlear implants were recruited from the Cochlear Implant Programme at a specialist children's hospital. The hearing participants were recruited from the same schools as those attended by the implanted adolescents. Participants were 18 cochlear implant users and 14 hearing controls, aged between 12 and 18 years. All used English as their main language and had no significant learning disability or neuro-developmental disorder. Short-term memory capacity was assessed in the auditory modality using Forward and Reverse Digit Span from the WISC IV UK, and visually using Forward and Reverse Memory from the Leiter-R. Individual word reading, reading comprehension and pseudoword decoding were assessed using the WIAT II UK. A series of ANOVAs revealed that the adolescents with cochlear implants had significantly poorer auditory short-term memory capacity and reading skills (on all measures) compared with their hearing peers. However, when Forward Digit Span was entered into the analyses as a covariate, none of the differences remained statistically significant. Deficits in immediate auditory memory persist into adolescence in deaf children with cochlear implants. Short-term auditory memory capacity is an important neurocognitive process in the development of reading skills after cochlear implantation in childhood that remains evident in later adolescence. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Short-Term and Working Memory Impairments in Early-Implanted, Long-Term Cochlear Implant Users Are Independent of Audibility and Speech Production.

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AuBuchon, Angela M; Pisoni, David B; Kronenberger, William G

2015-01-01

To determine whether early-implanted, long-term cochlear implant (CI) users display delays in verbal short-term and working memory capacity when processes related to audibility and speech production are eliminated. Twenty-three long-term CI users and 23 normal-hearing controls each completed forward and backward digit span tasks under testing conditions that differed in presentation modality (auditory or visual) and response output (spoken recall or manual pointing). Normal-hearing controls reproduced more lists of digits than the CI users, even when the test items were presented visually and the responses were made manually via touchscreen response. Short-term and working memory delays observed in CI users are not due to greater demands from peripheral sensory processes such as audibility or from overt speech-motor planning and response output organization. Instead, CI users are less efficient at encoding and maintaining phonological representations in verbal short-term memory using phonological and linguistic strategies during memory tasks.

Phonological Short-Term Memory, Working Memory and Foreign Language Performance in Intensive Language Learning

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Kormos, Judit; Safar, Anna

2008-01-01

In our research we addressed the question what the relationship is between phonological short-term and working memory capacity and performance in an end-of-year reading, writing, listening, speaking and use of English test. The participants of our study were 121 secondary school students aged 15-16 in the first intensive language training year of…

Visual Short-Term Memory: Is Capacity Dependent on Complexity or Familiarity?

DEFF Research Database (Denmark)

Sørensen, Thomas Alrik; Granlund, Rabia Line; Wiechmann, Maria

Several recent studies have explored the nature and limits of visual short-term memory (VSTM) (e.g. Luck & Vogel, 1997). A general VSTM capacity limit of about 3 to 4 objects has been found, confirming results from earlier studies (e.g. Cattell, 1885; Sperling, 1960). However, Alvarez and Cavanagh...

An information capacity limitation of visual short-term memory.

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Sewell, David K; Lilburn, Simon D; Smith, Philip L

2014-12-01

Research suggests that visual short-term memory (VSTM) has both an item capacity, of around 4 items, and an information capacity. We characterize the information capacity limits of VSTM using a task in which observers discriminated the orientation of a single probed item in displays consisting of 1, 2, 3, or 4 orthogonally oriented Gabor patch stimuli that were presented in noise for 50 ms, 100 ms, 150 ms, or 200 ms. The observed capacity limitations are well described by a sample-size model, which predicts invariance of ∑(i)(d'(i))² for displays of different sizes and linearity of (d'(i))² for displays of different durations. Performance was the same for simultaneous and sequentially presented displays, which implicates VSTM as the locus of the observed invariance and rules out explanations that ascribe it to divided attention or stimulus encoding. The invariance of ∑(i)(d'(i))² is predicted by the competitive interaction theory of Smith and Sewell (2013), which attributes it to the normalization of VSTM traces strengths arising from competition among stimuli entering VSTM. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Fast Weight Long Short-Term Memory

OpenAIRE

Keller, T. Anderson; Sridhar, Sharath Nittur; Wang, Xin

2018-01-01

Associative memory using fast weights is a short-term memory mechanism that substantially improves the memory capacity and time scale of recurrent neural networks (RNNs). As recent studies introduced fast weights only to regular RNNs, it is unknown whether fast weight memory is beneficial to gated RNNs. In this work, we report a significant synergy between long short-term memory (LSTM) networks and fast weight associative memories. We show that this combination, in learning associative retrie...

Color relations increase the capacity of visual short-term memory.

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Sanocki, Thomas; Sulman, Noah

2011-01-01

Do color relations such as similarity or harmony influence the ease with which colored patterns can be perceived and held in mind? We tested the influence of a relation supported in research on color harmony--similarity of hue--on the capacity of visual short-term memory (VSTM) for colors in patterns. Palettes of 4 similar-hue colors were rated as more pleasant (harmonious) than dissimilar-color palettes. The palettes were used in a VSTM color task. Patterns of 9 to 15 colored squares were presented, and accuracy of color change detection was measured. Memory performance was higher overall for similar-color palettes than for dissimilar-color palettes (experiments 1 and 3). Is this due to color similarity per se, or due to the harmony between colors in similar palettes? A final experiment provided strong support for the importance of color similarity as opposed to harmony. Overall, the advantages for color similarity, in terms of number of color squares held in memory (memory capacity) were 26% to 45% over dissimilar colors. The results indicate that color relations can have a strong impact on the capacity for perceiving and retaining color patterns.

Short-term memory capacity in networks via the restricted isometry property.

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Charles, Adam S; Yap, Han Lun; Rozell, Christopher J

2014-06-01

Cortical networks are hypothesized to rely on transient network activity to support short-term memory (STM). In this letter, we study the capacity of randomly connected recurrent linear networks for performing STM when the input signals are approximately sparse in some basis. We leverage results from compressed sensing to provide rigorous nonasymptotic recovery guarantees, quantifying the impact of the input sparsity level, the input sparsity basis, and the network characteristics on the system capacity. Our analysis demonstrates that network memory capacities can scale superlinearly with the number of nodes and in some situations can achieve STM capacities that are much larger than the network size. We provide perfect recovery guarantees for finite sequences and recovery bounds for infinite sequences. The latter analysis predicts that network STM systems may have an optimal recovery length that balances errors due to omission and recall mistakes. Furthermore, we show that the conditions yielding optimal STM capacity can be embodied in several network topologies, including networks with sparse or dense connectivities.

The nature of short-term consolidation in visual working memory.

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Ricker, Timothy J; Hardman, Kyle O

2017-11-01

Short-term consolidation is the process by which stable working memory representations are created. This process is fundamental to cognition yet poorly understood. The present work examines short-term consolidation using a Bayesian hierarchical model of visual working memory recall to determine the underlying processes at work. Our results show that consolidation functions largely through changing the proportion of memory items successfully maintained until test. Although there was some evidence that consolidation affects representational precision, this change was modest and could not account for the bulk of the consolidation effect on memory performance. The time course of the consolidation function and selective influence of consolidation on specific serial positions strongly indicates that short-term consolidation induces an attentional blink. The blink leads to deficits in memory for the immediately following item when time pressure is introduced. Temporal distinctiveness accounts of the consolidation process are tested and ruled out. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Impaired verbal short-term memory in Down syndrome reflects a capacity limitation rather than atypically rapid forgetting.

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M Purser, Harry R; Jarrold, Christopher

2005-05-01

Individuals with Down syndrome suffer from relatively poor verbal short-term memory. Recent work has indicated that this deficit is not caused by problems of audition, speech, or articulatory rehearsal within the phonological loop component of Baddeley and Hitch's working memory model. Given this, two experiments were conducted to investigate whether abnormally rapid decay underlies the deficit. In a first experiment, we attempted to vary the time available for decay using a modified serial recall procedure that had both verbal and visuospatial conditions. No evidence was found to suggest that forgetting is abnormally rapid in phonological memory in Down syndrome, but a selective phonological memory deficit was indicated. A second experiment further investigated possible problems of decay in phonological memory, restricted to item information. The results indicated that individuals with Down syndrome do not show atypically rapid item forgetting from phonological memory but may have a limited-capacity verbal short-term memory system.

Short term memory in echo state networks

OpenAIRE

Jaeger, H.

2001-01-01

The report investigates the short-term memory capacity of echo state recurrent neural networks. A quantitative measure MC of short-term memory capacity is introduced. The main result is that MC 5 N for networks with linear Output units and i.i.d. input, where N is network size. Conditions under which these maximal memory capacities are realized are described. Several theoretical and practical examples demonstrate how the short-term memory capacities of echo state networks can be exploited for...

Functional neuroimaging and behavioral correlates of capacity decline in visual short-term memory after sleep deprivation.

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Chee, Michael W L; Chuah, Y M Lisa

2007-05-29

Sleep deprivation (SD) impairs short-term memory, but it is unclear whether this is because of reduced storage capacity or processes contributing to appropriate information encoding. We evaluated 30 individuals twice, once after a night of normal sleep and again after 24 h of SD. In each session, we evaluated visual memory capacity by presenting arrays of one to eight colored squares. Additionally, we measured cortical responses to varying visual array sizes without engaging memory. The magnitude of intraparietal sulcus activation and memory capacity after normal sleep were highly correlated. SD elicited a pattern of activation in both tasks, indicating that deficits in visual processing and visual attention accompany and could account for loss of short-term memory capacity. Additionally, a comparison between better and poorer performers showed that preservation of precuneus and temporoparietal junction deactivation with increasing memory load corresponds to less performance decline when one is sleep-deprived.

Assessing the associative deficit of older adults in long-term and short-term/working memory.

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Chen, Tina; Naveh-Benjamin, Moshe

2012-09-01

Older adults exhibit a deficit in associative long-term memory relative to younger adults. However, the literature is inconclusive regarding whether this deficit is attenuated in short-term/working memory. To elucidate the issue, three experiments assessed younger and older adults' item and interitem associative memory and the effects of several variables that might potentially contribute to the inconsistent pattern of results in previous studies. In Experiment 1, participants were tested on item and associative recognition memory with both long-term and short-term retention intervals in a single, continuous recognition paradigm. There was an associative deficit for older adults in the short-term and long-term intervals. Using only short-term intervals, Experiment 2 utilized mixed and blocked test designs to examine the effect of test event salience. Blocking the test did not attenuate the age-related associative deficit seen in the mixed test blocks. Finally, an age-related associative deficit was found in Experiment 3, under both sequential and simultaneous presentation conditions. Even while accounting for some methodological issues, the associative deficit of older adults is evident in short-term/working memory.

Perceptions of short-term medical volunteer work: a qualitative study in Guatemala.

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Green, Tyler; Green, Heidi; Scandlyn, Jean; Kestler, Andrew

2009-02-26

Each year medical providers from wealthy countries participate in short-term medical volunteer work in resource-poor countries. Various authors have raised concern that such work has the potential to be harmful to recipient communities; however, the social science and medical literature contains little research into the perceptions of short-term medical volunteer work from the perspective of members of recipient communities. This exploratory study examines the perception of short-term medical volunteer work in Guatemala among groups of actors affected by or participating in these programs. The researchers conducted in-depth, semi-structured interviews with 72 individuals, including Guatemalan healthcare providers and health authorities, foreign medical providers, non-medical personnel working on health projects, and Guatemalan parents of children treated by a short-term volunteer group. Detailed notes and summaries of these interviews were uploaded, coded and annotated using Atlas.ti (Scientific Software Development GmbH, Berlin) to identify recurrent themes from the interviews. Informants commonly identified a need for increased access to medical services in Guatemala, and many believed that short-term medical volunteers are in a position to offer improved access to medical care in the communities where they serve. Informants most frequently cited appropriate patient selection and attention to payment systems as the best means to avoid creating dependence on foreign aid. The most frequent suggestion to improve short-term medical volunteer work was coordination with and respect for local Guatemalan healthcare providers and their communities, as insufficient understanding of the country's existing healthcare resources and needs may result in perceived harm to the recipient community. The perceived impact of short-term medical volunteer projects in Guatemala is highly variable and dependent upon the individual project. In this exploratory study, project

The hard fall effect: high working memory capacity leads to a higher, but less robust short-term memory performance.

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Thomassin, Noémylle; Gonthier, Corentin; Guerraz, Michel; Roulin, Jean-Luc

2015-01-01

Participants with a high working memory span tend to perform better than low spans in a variety of tasks. However, their performance is paradoxically more impaired when they have to perform two tasks at once, a phenomenon that could be labeled the "hard fall effect." The present study tested whether this effect exists in a short-term memory task, and investigated the proposal that the effect is due to high spans using efficient facilitative strategies under simple task conditions. Ninety-eight participants performed a spatial short-term memory task under simple and dual task conditions; stimuli presentation times either allowed for the use of complex facilitative strategies or not. High spans outperformed low spans only under simple task conditions when presentation times allowed for the use of facilitative strategies. These results indicate that the hard fall effect exists on a short-term memory task and may be caused by individual differences in strategy use.

Shared filtering processes link attentional and visual short-term memory capacity limits.

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Bettencourt, Katherine C; Michalka, Samantha W; Somers, David C

2011-09-30

Both visual attention and visual short-term memory (VSTM) have been shown to have capacity limits of 4 ± 1 objects, driving the hypothesis that they share a visual processing buffer. However, these capacity limitations also show strong individual differences, making the degree to which these capacities are related unclear. Moreover, other research has suggested a distinction between attention and VSTM buffers. To explore the degree to which capacity limitations reflect the use of a shared visual processing buffer, we compared individual subject's capacities on attentional and VSTM tasks completed in the same testing session. We used a multiple object tracking (MOT) and a VSTM change detection task, with varying levels of distractors, to measure capacity. Significant correlations in capacity were not observed between the MOT and VSTM tasks when distractor filtering demands differed between the tasks. Instead, significant correlations were seen when the tasks shared spatial filtering demands. Moreover, these filtering demands impacted capacity similarly in both attention and VSTM tasks. These observations fail to support the view that visual attention and VSTM capacity limits result from a shared buffer but instead highlight the role of the resource demands of underlying processes in limiting capacity.

Synaptic Correlates of Working Memory Capacity.

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Mi, Yuanyuan; Katkov, Mikhail; Tsodyks, Misha

2017-01-18

Psychological studies indicate that human ability to keep information in readily accessible working memory is limited to four items for most people. This extremely low capacity severely limits execution of many cognitive tasks, but its neuronal underpinnings remain unclear. Here we show that in the framework of synaptic theory of working memory, capacity can be analytically estimated to scale with characteristic time of short-term synaptic depression relative to synaptic current time constant. The number of items in working memory can be regulated by external excitation, enabling the system to be tuned to the desired load and to clear the working memory of currently held items to make room for new ones. Copyright © 2017 Elsevier Inc. All rights reserved.

Short-term memory across eye blinks.

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Irwin, David E

2014-01-01

The effect of eye blinks on short-term memory was examined in two experiments. On each trial, participants viewed an initial display of coloured, oriented lines, then after a retention interval they viewed a test display that was either identical or different by one feature. Participants kept their eyes open throughout the retention interval on some blocks of trials, whereas on others they made a single eye blink. Accuracy was measured as a function of the number of items in the display to determine the capacity of short-term memory on blink and no-blink trials. In separate blocks of trials participants were instructed to remember colour only, orientation only, or both colour and orientation. Eye blinks reduced short-term memory capacity by approximately 0.6-0.8 items for both feature and conjunction stimuli. A third, control, experiment showed that a button press during the retention interval had no effect on short-term memory capacity, indicating that the effect of an eye blink was not due to general motoric dual-task interference. Eye blinks might instead reduce short-term memory capacity by interfering with attention-based rehearsal processes.

Verbal Short-Term Memory Span in Speech-Disordered Children: Implications for Articulatory Coding in Short-Term Memory.

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Raine, Adrian; And Others

1991-01-01

Children with speech disorders had lower short-term memory capacity and smaller word length effect than control children. Children with speech disorders also had reduced speech-motor activity during rehearsal. Results suggest that speech rate may be a causal determinant of verbal short-term memory capacity. (BC)

The frontal eye fields limit the capacity of visual short-term memory in rhesus monkeys.

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Lee, Kyoung-Min; Ahn, Kyung-Ha

2013-01-01

The frontal eye fields (FEF) in rhesus monkeys have been implicated in visual short-term memory (VSTM) as well as control of visual attention. Here we examined the importance of the area in the VSTM capacity and the relationship between VSTM and attention, using the chemical inactivation technique and multi-target saccade tasks with or without the need of target-location memory. During FEF inactivation, serial saccades to targets defined by color contrast were unaffected, but saccades relying on short-term memory were impaired when the target count was at the capacity limit of VSTM. The memory impairment was specific to the FEF-coded retinotopic locations, and subject to competition among targets distributed across visual fields. These results together suggest that the FEF plays a crucial role during the entry of information into VSTM, by enabling attention deployment on targets to be remembered. In this view, the memory capacity results from the limited availability of attentional resources provided by FEF: The FEF can concurrently maintain only a limited number of activations to register the targets into memory. When lesions render part of the area unavailable for activation, the number would decrease, further reducing the capacity of VSTM.

The development of working memory capacity and fluid intelligence in children

OpenAIRE

Engel de Abreu, Pascale; Gathercole, S; Conway, A

2010-01-01

A longitudinal study was conducted to investigate the relationship between working memory capacity and fluid intelligence and how this relationship develops in early childhood. The major aim was to determine which aspect of the working memory system – short-term storage or executive attention – drives the relationship with fluid intelligence. A sample of 119 children was followed from kindergarten to second grade and completed multiple assessments of short-term memory, wor...

The development of a short domain-general measure of working memory capacity.

Science.gov (United States)

Oswald, Frederick L; McAbee, Samuel T; Redick, Thomas S; Hambrick, David Z

2015-12-01

Working memory capacity is one of the most frequently measured individual difference constructs in cognitive psychology and related fields. However, implementation of complex span and other working memory measures is generally time-consuming for administrators and examinees alike. Because researchers often must manage the tension between limited testing time and measuring numerous constructs reliably, a short and effective measure of working memory capacity would often be a major practical benefit in future research efforts. The current study developed a shortened computerized domain-general measure of working memory capacity by representatively sampling items from three existing complex working memory span tasks: operation span, reading span, and symmetry span. Using a large archival data set (Study 1, N = 4,845), we developed and applied a principled strategy for developing the reduced measure, based on testing a series of confirmatory factor analysis models. Adequate fit indices from these models lent support to this strategy. The resulting shortened measure was then administered to a second independent sample (Study 2, N = 172), demonstrating that the new measure saves roughly 15 min (30%) of testing time on average, and even up to 25 min depending on the test-taker. On the basis of these initial promising findings, several directions for future research are discussed.

Impaired Semantic Knowledge Underlies the Reduced Verbal Short-Term Storage Capacity in Alzheimer's Disease

Science.gov (United States)

Peters, Frederic; Majerus, Steve; De Baerdemaeker, Julie; Salmon, Eric; Collette, Fabienne

2009-01-01

A decrease in verbal short-term memory (STM) capacity is consistently observed in patients with Alzheimer's disease (AD). Although this impairment has been mainly attributed to attentional deficits during encoding and maintenance, the progressive deterioration of semantic knowledge in early stages of AD may also be an important determinant of poor…

Temporal precision and the capacity of auditory-verbal short-term memory.

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Gilbert, Rebecca A; Hitch, Graham J; Hartley, Tom

2017-12-01

The capacity of serially ordered auditory-verbal short-term memory (AVSTM) is sensitive to the timing of the material to be stored, and both temporal processing and AVSTM capacity are implicated in the development of language. We developed a novel "rehearsal-probe" task to investigate the relationship between temporal precision and the capacity to remember serial order. Participants listened to a sub-span sequence of spoken digits and silently rehearsed the items and their timing during an unfilled retention interval. After an unpredictable delay, a tone prompted report of the item being rehearsed at that moment. An initial experiment showed cyclic distributions of item responses over time, with peaks preserving serial order and broad, overlapping tails. The spread of the response distributions increased with additional memory load and correlated negatively with participants' auditory digit spans. A second study replicated the negative correlation and demonstrated its specificity to AVSTM by controlling for differences in visuo-spatial STM and nonverbal IQ. The results are consistent with the idea that a common resource underpins both the temporal precision and capacity of AVSTM. The rehearsal-probe task may provide a valuable tool for investigating links between temporal processing and AVSTM capacity in the context of speech and language abilities.

Short-term oleoyl-estrone treatment affects capacity to manage lipids in rat adipose tissue.

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Salas, Anna; Noé, Véronique; Ciudad, Carlos J; Romero, M Mar; Remesar, Xavier; Esteve, Montserrat

2007-08-28

Short-term OE (oleoyl-estrone) treatment causes significant decreases in rat weight mainly due to adipose tissue loss. The aim of this work was to determine if OE treatment affects the expression of genes that regulate lipid metabolism in white adipose tissue. Gene expression in adipose tissue from female treated rats (48 hours) was analysed by hybridization to cDNA arrays and levels of specific mRNAs were determined by real-time PCR. Treatment with OE decreased the expression of 232 genes and up-regulated 75 other genes in mesenteric white adipose tissue. The use of real-time PCR validate that, in mesenteric white adipose tissue, mRNA levels for Lipoprotein Lipase (LPL) were decreased by 52%, those of Fatty Acid Synthase (FAS) by 95%, those of Hormone Sensible Lipase (HSL) by 32%, those of Acetyl CoA Carboxylase (ACC) by 92%, those of Carnitine Palmitoyltransferase 1b (CPT1b) by 45%, and those of Fatty Acid Transport Protein 1 (FATP1) and Adipocyte Fatty Acid Binding Protein (FABP4) by 52% and 49%, respectively. Conversely, Tumour Necrosis Factor (TNFalpha) values showed overexpression (198%). Short-term treatment with OE affects adipose tissue capacity to extract fatty acids from lipoproteins and to deal with fatty acid transport and metabolism.

The frontal eye fields limit the capacity of visual short-term memory in rhesus monkeys.

Directory of Open Access Journals (Sweden)

Kyoung-Min Lee

Full Text Available The frontal eye fields (FEF in rhesus monkeys have been implicated in visual short-term memory (VSTM as well as control of visual attention. Here we examined the importance of the area in the VSTM capacity and the relationship between VSTM and attention, using the chemical inactivation technique and multi-target saccade tasks with or without the need of target-location memory. During FEF inactivation, serial saccades to targets defined by color contrast were unaffected, but saccades relying on short-term memory were impaired when the target count was at the capacity limit of VSTM. The memory impairment was specific to the FEF-coded retinotopic locations, and subject to competition among targets distributed across visual fields. These results together suggest that the FEF plays a crucial role during the entry of information into VSTM, by enabling attention deployment on targets to be remembered. In this view, the memory capacity results from the limited availability of attentional resources provided by FEF: The FEF can concurrently maintain only a limited number of activations to register the targets into memory. When lesions render part of the area unavailable for activation, the number would decrease, further reducing the capacity of VSTM.

Short-term memory in Down syndrome: applying the working memory model.

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Jarrold, C; Baddeley, A D

2001-10-01

This paper is divided into three sections. The first reviews the evidence for a verbal short-term memory deficit in Down syndrome. Existing research suggests that short-term memory for verbal information tends to be impaired in Down syndrome, in contrast to short-term memory for visual and spatial material. In addition, problems of hearing or speech do not appear to be a major cause of difficulties on tests of verbal short-term memory. This suggests that Down syndrome is associated with a specific memory problem, which we link to a potential deficit in the functioning of the 'phonological loop' of Baddeley's (1986) model of working memory. The second section considers the implications of a phonological loop problem. Because a reasonable amount is known about the normal functioning of the phonological loop, and of its role in language acquisition in typical development, we can make firm predictions as to the likely nature of the short-term memory problem in Down syndrome, and its consequences for language learning. However, we note that the existing evidence from studies with individuals with Down syndrome does not fit well with these predictions. This leads to the third section of the paper, in which we consider key questions to be addressed in future research. We suggest that there are two questions to be answered, which follow directly from the contradictory results outlined in the previous section. These are 'What is the precise nature of the verbal short-term memory deficit in Down syndrome', and 'What are the consequences of this deficit for learning'. We discuss ways in which these questions might be addressed in future work.

Short term clearing of capacity markets : an alternative approach to capacity pricing

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Sadeghi, Ariobarzan; Torbaghan, Shahab Shariat; Gibescu, Madeleine

2017-01-01

In the presence of increasing penetration from renewable energy sources, several control areas in Europe and the US have introduced Capacity Remuneration Mechanisms (CRMs) to ensure sufficient investment in firm electricity generation capacity. However, due to their long-term focus, these mechanisms

Short-term oleoyl-estrone treatment affects capacity to manage lipids in rat adipose tissue

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Remesar Xavier

2007-08-01

Full Text Available Abstract Background Short-term OE (oleoyl-estrone treatment causes significant decreases in rat weight mainly due to adipose tissue loss. The aim of this work was to determine if OE treatment affects the expression of genes that regulate lipid metabolism in white adipose tissue. Results Gene expression in adipose tissue from female treated rats (48 hours was analysed by hybridization to cDNA arrays and levels of specific mRNAs were determined by real-time PCR. Treatment with OE decreased the expression of 232 genes and up-regulated 75 other genes in mesenteric white adipose tissue. The use of real-time PCR validate that, in mesenteric white adipose tissue, mRNA levels for Lipoprotein Lipase (LPL were decreased by 52%, those of Fatty Acid Synthase (FAS by 95%, those of Hormone Sensible Lipase (HSL by 32%, those of Acetyl CoA Carboxylase (ACC by 92%, those of Carnitine Palmitoyltransferase 1b (CPT1b by 45%, and those of Fatty Acid Transport Protein 1 (FATP1 and Adipocyte Fatty Acid Binding Protein (FABP4 by 52% and 49%, respectively. Conversely, Tumour Necrosis Factor (TNFα values showed overexpression (198%. Conclusion Short-term treatment with OE affects adipose tissue capacity to extract fatty acids from lipoproteins and to deal with fatty acid transport and metabolism.

Fragile visual short-term memory is an object-based and location-specific store

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Pinto, Y.; Sligte, I.G.; Shapiro, K.L.; Lamme, V.A.F.

2013-01-01

Fragile visual short-term memory (FM) is a recently discovered form of visual short-term memory. Evidence suggests that it provides rich and high-capacity storage, like iconic memory, yet it exists, without interference, almost as long as visual working memory. In the present study, we sought to

The magical number 4 in short-term memory: a reconsideration of mental storage capacity.

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Cowan, N

2001-02-01

Miller (1956) summarized evidence that people can remember about seven chunks in short-term memory (STM) tasks. However, that number was meant more as a rough estimate and a rhetorical device than as a real capacity limit. Others have since suggested that there is a more precise capacity limit, but that it is only three to five chunks. The present target article brings together a wide variety of data on capacity limits suggesting that the smaller capacity limit is real. Capacity limits will be useful in analyses of information processing only if the boundary conditions for observing them can be carefully described. Four basic conditions in which chunks can be identified and capacity limits can accordingly be observed are: (1) when information overload limits chunks to individual stimulus items, (2) when other steps are taken specifically to block the recording of stimulus items into larger chunks, (3) in performance discontinuities caused by the capacity limit, and (4) in various indirect effects of the capacity limit. Under these conditions, rehearsal and long-term memory cannot be used to combine stimulus items into chunks of an unknown size; nor can storage mechanisms that are not capacity-limited, such as sensory memory, allow the capacity-limited storage mechanism to be refilled during recall. A single, central capacity limit averaging about four chunks is implicated along with other, noncapacity-limited sources. The pure STM capacity limit expressed in chunks is distinguished from compound STM limits obtained when the number of separately held chunks is unclear. Reasons why pure capacity estimates fall within a narrow range are discussed and a capacity limit for the focus of attention is proposed.

The Demonstration of Short-Term Consolidation.

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Jolicoeur, Pierre; Dell'Acqua, Roberto

1998-01-01

Results of seven experiments involving 112 college students or staff using a dual-task approach provide evidence that encoding information into short-term memory involves a distinct process termed short-term consolidation (STC). Results suggest that STC has limited capacity and that it requires central processing mechanisms. (SLD)

Computer Simulations of Developmental Change: The Contributions of Working Memory Capacity and Long-Term Knowledge

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Jones, Gary; Gobet, Fernand; Pine, Julian M.

2008-01-01

Increasing working memory (WM) capacity is often cited as a major influence on children's development and yet WM capacity is difficult to examine independently of long-term knowledge. A computational model of children's nonword repetition (NWR) performance is presented that independently manipulates long-term knowledge and WM capacity to determine…

Magnetic stimulation of the dorsolateral prefrontal cortex dissociates fragile visual short-term memory from visual working memory.

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Sligte, Ilja G; Wokke, Martijn E; Tesselaar, Johannes P; Scholte, H Steven; Lamme, Victor A F

2011-05-01

To guide our behavior in successful ways, we often need to rely on information that is no longer in view, but maintained in visual short-term memory (VSTM). While VSTM is usually broken down into iconic memory (brief and high-capacity store) and visual working memory (sustained, yet limited-capacity store), recent studies have suggested the existence of an additional and intermediate form of VSTM that depends on activity in extrastriate cortex. In previous work, we have shown that this fragile form of VSTM can be dissociated from iconic memory. In the present study, we provide evidence that fragile VSTM is different from visual working memory as magnetic stimulation of the right dorsolateral prefrontal cortex (DLPFC) disrupts visual working memory, while leaving fragile VSTM intact. In addition, we observed that people with high DLPFC activity had superior working memory capacity compared to people with low DLPFC activity, and only people with high DLPFC activity really showed a reduction in working memory capacity in response to magnetic stimulation. Altogether, this study shows that VSTM consists of three stages that have clearly different characteristics and rely on different neural structures. On the methodological side, we show that it is possible to predict individual susceptibility to magnetic stimulation based on functional MRI activity. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

Sentence Processing as a Function of Syntax, Short Term Memory Capacity, the Meaningfulness of the Stimulus and Age

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Gamlin, Peter J.

1971-01-01

Examines the effects of short term memory (STM) capacity, meaningfulness of stimuli, and age upon listeners' structuring of sentences. Results show that the interaction between STM capacity and meaningfulness (1) approached significance when data were collapsed over both age levels, and (2) was significant for one age level. Tables and references.…

No Clear Association between Impaired Short-Term or Working Memory Storage and Time Reproduction Capacity in Adult ADHD Patients.

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Mette, Christian; Grabemann, Marco; Zimmermann, Marco; Strunz, Laura; Scherbaum, Norbert; Wiltfang, Jens; Kis, Bernhard

2015-01-01

Altered time reproduction is exhibited by patients with adult attention deficit hyperactivity disorder (ADHD). It remains unclear whether memory capacity influences the ability of adults with ADHD to reproduce time intervals. We conducted a behavioral study on 30 ADHD patients who were medicated with methylphenidate, 29 unmedicated adult ADHD patients and 32 healthy controls (HCs). We assessed time reproduction using six time intervals (1 s, 4 s, 6 s, 10 s, 24 s and 60 s) and assessed memory performance using the Wechsler memory scale. The patients with ADHD exhibited lower memory performance scores than the HCs. No significant differences in the raw scores for any of the time intervals (p > .05), with the exception of the variability at the short time intervals (1 s, 4 s and 6 s) (p memory performance (p > .05). We detected no findings indicating that working memory might influence time reproduction in adult patients with ADHD. Therefore, further studies concerning time reproduction and memory capacity among adult patients with ADHD must be performed to verify and replicate the present findings.

No Clear Association between Impaired Short-Term or Working Memory Storage and Time Reproduction Capacity in Adult ADHD Patients.

Directory of Open Access Journals (Sweden)

Christian Mette

Full Text Available Altered time reproduction is exhibited by patients with adult attention deficit hyperactivity disorder (ADHD. It remains unclear whether memory capacity influences the ability of adults with ADHD to reproduce time intervals.We conducted a behavioral study on 30 ADHD patients who were medicated with methylphenidate, 29 unmedicated adult ADHD patients and 32 healthy controls (HCs. We assessed time reproduction using six time intervals (1 s, 4 s, 6 s, 10 s, 24 s and 60 s and assessed memory performance using the Wechsler memory scale.The patients with ADHD exhibited lower memory performance scores than the HCs. No significant differences in the raw scores for any of the time intervals (p > .05, with the exception of the variability at the short time intervals (1 s, 4 s and 6 s (p .05.We detected no findings indicating that working memory might influence time reproduction in adult patients with ADHD. Therefore, further studies concerning time reproduction and memory capacity among adult patients with ADHD must be performed to verify and replicate the present findings.

Beyond the magic number four: Remapping high-capacity, pre-attentive, fragile working memory

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Zerr, P.; Gayet, S.; Mulder, K.T.; Sligte, I.G.; Stigchel, S. van der

2017-01-01

Visual short term memory allows us to access visual information after termination of its retinal input. Generally, a distinction is made between a robust, capacity-limited form (working memory, WM) and high-capacity, pre-attentive, maskable forms (sensory memory, e.g. fragile memory, FM). Eye

Short term memory and working memory in blind versus sighted children.

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Withagen, Ans; Kappers, Astrid M L; Vervloed, Mathijs P J; Knoors, Harry; Verhoeven, Ludo

2013-07-01

There is evidence that blind people may strengthen their memory skills to compensate for absence of vision. However, which aspects of memory are involved is open to debate and a developmental perspective is generally lacking. In the present study, we compared the short term memory (STM) and working memory (WM) of 10-year-old blind children and sighted children. STM was measured using digit span forward, name learning, and word span tasks; WM was measured using listening span and digit span backward tasks. The blind children outperformed their sighted peers on both STM and WM tasks. The enhanced capacity of the blind children on digit span and other STM tasks confirms the results of earlier research; the significantly better performance of the blind children relative to their sighted peers on verbal WM tasks is a new interesting finding. Task characteristics, including the verbal nature of the WM tasks and strategies used to perform these tasks, are discussed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Capacity and precision in an animal model of visual short-term memory.

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Lara, Antonio H; Wallis, Jonathan D

2012-03-14

Temporary storage of information in visual short-term memory (VSTM) is a key component of many complex cognitive abilities. However, it is highly limited in capacity. Understanding the neurophysiological nature of this capacity limit will require a valid animal model of VSTM. We used a multiple-item color change detection task to measure macaque monkeys' VSTM capacity. Subjects' performance deteriorated and reaction times increased as a function of the number of items in memory. Additionally, we measured the precision of the memory representations by varying the distance between sample and test colors. In trials with similar sample and test colors, subjects made more errors compared to trials with highly discriminable colors. We modeled the error distribution as a Gaussian function and used this to estimate the precision of VSTM representations. We found that as the number of items in memory increases the precision of the representations decreases dramatically. Additionally, we found that focusing attention on one of the objects increases the precision with which that object is stored and degrades the precision of the remaining. These results are in line with recent findings in human psychophysics and provide a solid foundation for understanding the neurophysiological nature of the capacity limit of VSTM.

Hippocampal and posterior parietal contributions to developmental increases in visual short-term memory capacity.

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von Allmen, David Yoh; Wurmitzer, Karoline; Klaver, Peter

2014-10-01

Developmental increases in visual short-term memory (VSTM) capacity have been associated with changes in attention processing limitations and changes in neural activity within neural networks including the posterior parietal cortex (PPC). A growing body of evidence suggests that the hippocampus plays a role in VSTM, but it is unknown whether the hippocampus contributes to the capacity increase across development. We investigated the functional development of the hippocampus and PPC in 57 children, adolescents and adults (age 8-27 years) who performed a visuo-spatial change detection task. A negative relationship between age and VSTM related activity was found in the right posterior hippocampus that was paralleled by a positive age-activity relationship in the right PPC. In the posterior hippocampus, VSTM related activity predicted individual capacity in children, whereas neural activity in the right anterior hippocampus predicted individual capacity in adults. The findings provide first evidence that VSTM development is supported by an integrated neural network that involves hippocampal and posterior parietal regions.

Working Memory and Short-Term Memory Abilities in Accomplished Multilinguals

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Biedron, Adriana; Szczepaniak, Anna

2012-01-01

The role of short-term memory and working memory in accomplished multilinguals was investigated. Twenty-eight accomplished multilinguals were compared to 36 mainstream philology students. The following instruments were used in the study: three memory subtests of the Wechsler Intelligence Scale (Digit Span, Digit-Symbol Coding, and Arithmetic,…

Visual working memory capacity and the medial temporal lobe.

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Jeneson, Annette; Wixted, John T; Hopkins, Ramona O; Squire, Larry R

2012-03-07

Patients with medial temporal lobe (MTL) damage are sometimes impaired at remembering visual information across delays as short as a few seconds. Such impairments could reflect either impaired visual working memory capacity or impaired long-term memory (because attention has been diverted or because working memory capacity has been exceeded). Using a standard change-detection task, we asked whether visual working memory capacity is intact or impaired after MTL damage. Five patients with hippocampal lesions and one patient with large MTL lesions saw an array of 1, 2, 3, 4, or 6 colored squares, followed after 3, 4, or 8 s by a second array where one of the colored squares was cued. The task was to decide whether the cued square had the same color as the corresponding square in the first array or a different color. At the 1 s delay typically used to assess working memory capacity, patients performed as well as controls at all array sizes. At the longer delays, patients performed as well as controls at small array sizes, thought to be within the capacity limit, and worse than controls at large array sizes, thought to exceed the capacity limit. The findings suggest that visual working memory capacity in humans is intact after damage to the MTL structures and that damage to these structures impairs performance only when visual working memory is insufficient to support performance.

The many faces of working memory and short-term storage.

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Cowan, Nelson

2017-08-01

The topic of working memory (WM) is ubiquitous in research on cognitive psychology and on individual differences. According to one definition, it is a small amount of information kept in a temporary state of heightened accessibility; it is used in most types of communication and problem solving. Short-term storage has been defined as the passive (i.e., non-attention-based, nonstrategic) component of WM or, alternatively, as a passive store separate from an attention-based WM. Here I note that much confusion has been created by the use by various investigators of many, subtly different definitions of WM and short-term storage. The definitions are sometimes made explicit and sometimes implied. As I explain, the different definitions may have stemmed from the use of a wide variety of techniques to explore WM, along with differences in theoretical orientation. By delineating nine previously used definitions of WM and explaining how additional ones may emerge from combinations of these nine, I hope to improve scientific discourse on WM. The potential advantages of clarity about definitions of WM and short-term storage are illustrated with respect to several ongoing research controversies.

Dissociating Measures of Consciousness from Measures of Short-Term Memory

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Sørensen, Thomas Alrik; Ásgeirsson, Árni Gunnar; Staugaard, Camilla Funch

Often, the contents of consciousness are equated with the contents of short-term memory (or working memory), sometimes to a point where they are treated as identical entities. In the present study we aimed to investigate whether they may be modulated independently and thus dissociated from each...... if conscious content simply can be reduced to a cognitive process like short-term memory. In two experiments, we combined two different measures of short-term memory capacity to investigate how manipulations of set-size affect performance in observers with the Perceptual Awareness Scale (PAS) to measure...... conscious experience of the stimulus in every trial (Ramsøy & Overgaard, 2004; Overgaard & Sørensen, 2004). We trained observers to report their experience of a visual target stimulus on the four-point PAS scale; ranging from “no experience” to “clear experience”. To measure short-term memory we used...

Dynamical Origin of the Effective Storage Capacity in the Brain's Working Memory

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Bick, Christian; Rabinovich, Mikhail I.

2009-11-01

The capacity of working memory (WM), a short-term buffer for information in the brain, is limited. We suggest a model for sequential WM that is based upon winnerless competition amongst representations of available informational items. Analytical results for the underlying mathematical model relate WM capacity and relative lateral inhibition in the corresponding neural network. This implies an upper bound for WM capacity, which is, under reasonable neurobiological assumptions, close to the “magical number seven.”

Remembering over the short-term: the case against the standard model.

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Nairne, James S

2002-01-01

Psychologists often assume that short-term storage is synonymous with activation, a mnemonic property that keeps information in an immediately accessible form. Permanent knowledge is activated, as a result of on-line cognitive processing, and an activity trace is established "in" short-term (or working) memory. Activation is assumed to decay spontaneously with the passage of time, so a refreshing process-rehearsal-is needed to maintain availability. Most of the phenomena of immediate retention, such as capacity limitations and word length effects, are assumed to arise from trade-offs between rehearsal and decay. This "standard model" of how we remember over the short-term still enjoys considerable popularity, although recent research questions most of its main assumptions. In this chapter I review the recent research and identify the empirical and conceptual problems that plague traditional conceptions of short-term memory. Increasingly, researchers are recognizing that short-term retention is cue driven, much like long-term memory, and that neither rehearsal nor decay is likely to explain the particulars of short-term forgetting.

The interaction of short-term and long-term memory in phonetic category formation

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Harnsberger, James D.

2002-05-01

This study examined the role that short-term memory capacity plays in the relationship between novel stimuli (e.g., non-native speech sounds, native nonsense words) and phonetic categories in long-term memory. Thirty native speakers of American English were administered five tests: categorial AXB discrimination using nasal consonants from Malayalam; categorial identification, also using Malayalam nasals, which measured the influence of phonetic categories in long-term memory; digit span; nonword span, a short-term memory measure mediated by phonetic categories in long-term memory; and paired-associate word learning (word-word and word-nonword pairs). The results showed that almost all measures were significantly correlated with one another. The strongest predictor for the discrimination and word-nonword learning results was nonword (r=+0.62) and digit span (r=+0.51), respectively. When the identification test results were partialed out, only nonword span significantly correlated with discrimination. The results show a strong influence of short-term memory capacity on the encoding of phonetic detail within phonetic categories and suggest that long-term memory representations regulate the capacity of short-term memory to preserve information for subsequent encoding. The results of this study will also be discussed with regards to resolving the tension between episodic and abstract models of phonetic category structure.

An Agent-Based Model for the Role of Short-Term Memory Enhancement in the Emergence of Grammatical Agreement.

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Vera, Javier

2018-01-01

What is the influence of short-term memory enhancement on the emergence of grammatical agreement systems in multi-agent language games? Agreement systems suppose that at least two words share some features with each other, such as gender, number, or case. Previous work, within the multi-agent language-game framework, has recently proposed models stressing the hypothesis that the emergence of a grammatical agreement system arises from the minimization of semantic ambiguity. On the other hand, neurobiological evidence argues for the hypothesis that language evolution has mainly related to an increasing of short-term memory capacity, which has allowed the online manipulation of words and meanings participating particularly in grammatical agreement systems. Here, the main aim is to propose a multi-agent language game for the emergence of a grammatical agreement system, under measurable long-range relations depending on the short-term memory capacity. Computer simulations, based on a parameter that measures the amount of short-term memory capacity, suggest that agreement marker systems arise in a population of agents equipped at least with a critical short-term memory capacity.

Individual differences in rate of encoding predict estimates of visual short-term memory capacity (K).

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Jannati, Ali; McDonald, John J; Di Lollo, Vincent

2015-06-01

The capacity of visual short-term memory (VSTM) is commonly estimated by K scores obtained with a change-detection task. Contrary to common belief, K may be influenced not only by capacity but also by the rate at which stimuli are encoded into VSTM. Experiment 1 showed that, contrary to earlier conclusions, estimates of VSTM capacity obtained with a change-detection task are constrained by temporal limitations. In Experiment 2, we used change-detection and backward-masking tasks to obtain separate within-subject estimates of K and of rate of encoding, respectively. A median split based on rate of encoding revealed significantly higher K estimates for fast encoders. Moreover, a significant correlation was found between K and the estimated rate of encoding. The present findings raise the prospect that the reported relationships between K and such cognitive concepts as fluid intelligence may be mediated not only by VSTM capacity but also by rate of encoding. (c) 2015 APA, all rights reserved).

Short-term memory of movements at the children age 11 and 12

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Marjanović Anka

2006-01-01

Full Text Available Pantomimed actions recall has been examined on the sample of 11-12 years old school children, employing the standard technique that requires reproduction of pantomimed meaningful and meaningless actions. Forward and backward digit span tasks have been used in the same experimental session to provide a rough estimate of the short-term storage and working memory capacity. Correlation between meaningless actions reproduction and backward digit span has been established, while the difference in meaningful and meaningless actions reproduction remained insignificant. The examined data have been discussed in the frame of short-term working memory role in actions remembering debate.

Short-term memory

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Toulouse, G.

This is a rather bold attempt to bridge the gap between neuron structure and psychological data. We try to answer the question: Is there a relation between the neuronal connectivity in the human cortex (around 5,000) and the short-term memory capacity (7±2)? Our starting point is the Hopfield model (Hopfield 1982), presented in this volume by D.J. Amit.

Proactive interference does not meaningfully distort visual working memory capacity estimates in the canonical change detection task

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Po-Han eLin

2012-02-01

Full Text Available The change detection task has become a standard method for estimating the storage capacity of visual working memory. Most researchers assume that this task isolates the properties of an active short-term storage system that can be dissociated from long-term memory systems. However, long-term memory storage may influence performance on this task. In particular, memory traces from previous trials may create proactive interference that sometimes leads to errors, thereby reducing estimated capacity. Consequently, the capacity of visual working memory may be higher than is usually thought, and correlations between capacity and other measures of cognition may reflect individual differences in proactive interference rather than individual differences in the capacity of the short-term storage system. Indeed, previous research has shown that change detection performance can be influenced by proactive interference under some conditions. The purpose of the present study was to determine whether the canonical version of the change detection task—in which the to-be-remembered information consists of simple, briefly presented features—is influenced by proactive interference. Two experiments were conducted using methods that ordinarily produce substantial evidence of proactive interference, but no proactive interference was observed. Thus, the canonical version of the change detection task can be used to assess visual working memory capacity with no meaningful influence of proactive interference.

Proactive interference does not meaningfully distort visual working memory capacity estimates in the canonical change detection task.

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Lin, Po-Han; Luck, Steven J

2012-01-01

The change detection task has become a standard method for estimating the storage capacity of visual working memory. Most researchers assume that this task isolates the properties of an active short-term storage system that can be dissociated from long-term memory systems. However, long-term memory storage may influence performance on this task. In particular, memory traces from previous trials may create proactive interference that sometimes leads to errors, thereby reducing estimated capacity. Consequently, the capacity of visual working memory may be higher than is usually thought, and correlations between capacity and other measures of cognition may reflect individual differences in proactive interference rather than individual differences in the capacity of the short-term storage system. Indeed, previous research has shown that change detection performance can be influenced by proactive interference under some conditions. The purpose of the present study was to determine whether the canonical version of the change detection task - in which the to-be-remembered information consists of simple, briefly presented features - is influenced by proactive interference. Two experiments were conducted using methods that ordinarily produce substantial evidence of proactive interference, but no proactive interference was observed. Thus, the canonical version of the change detection task can be used to assess visual working memory capacity with no meaningful influence of proactive interference.

About the distinction between working memory and short-term memory

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Bart eAben

2012-08-01

Full Text Available The theoretical concepts short-term memory (STM and working memory (WM have been used to refer to the maintenance and the maintenance plus manipulation of memory, respectively. Although they are conceptually different, the use of the terms STM and WM in literature is not always strict. Short-term memory and WM are different theoretical concepts that are assumed to reflect different cognitive functions. However, correlational studies have not been able to separate both constructs consistently and there is evidence for a large or even complete overlap. The emerging view from neurobiological studies is partly different, although there are conceptual problems troubling the interpretation of findings. In this regard, there is a crucial role for the tasks that are used to measure STM or WM (simple and complex span tasks, respectively and for the cognitive load reflected by factors like attention and processing speed that may covary between and within these tasks. These conceptual issues are discussed based on several abstract models for the relation between STM and WM.

A shared, flexible neural map architecture reflects capacity limits in both visual short-term memory and enumeration.

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Knops, André; Piazza, Manuela; Sengupta, Rakesh; Eger, Evelyn; Melcher, David

2014-07-23

Human cognition is characterized by severe capacity limits: we can accurately track, enumerate, or hold in mind only a small number of items at a time. It remains debated whether capacity limitations across tasks are determined by a common system. Here we measure brain activation of adult subjects performing either a visual short-term memory (vSTM) task consisting of holding in mind precise information about the orientation and position of a variable number of items, or an enumeration task consisting of assessing the number of items in those sets. We show that task-specific capacity limits (three to four items in enumeration and two to three in vSTM) are neurally reflected in the activity of the posterior parietal cortex (PPC): an identical set of voxels in this region, commonly activated during the two tasks, changed its overall response profile reflecting task-specific capacity limitations. These results, replicated in a second experiment, were further supported by multivariate pattern analysis in which we could decode the number of items presented over a larger range during enumeration than during vSTM. Finally, we simulated our results with a computational model of PPC using a saliency map architecture in which the level of mutual inhibition between nodes gives rise to capacity limitations and reflects the task-dependent precision with which objects need to be encoded (high precision for vSTM, lower precision for enumeration). Together, our work supports the existence of a common, flexible system underlying capacity limits across tasks in PPC that may take the form of a saliency map. Copyright © 2014 the authors 0270-6474/14/349857-10$15.00/0.

Episodic Short-Term Recognition Requires Encoding into Visual Working Memory: Evidence from Probe Recognition after Letter Report.

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Poth, Christian H; Schneider, Werner X

2016-01-01

Human vision is organized in discrete processing episodes (e.g., eye fixations or task-steps). Object information must be transmitted across episodes to enable episodic short-term recognition: recognizing whether a current object has been seen in a previous episode. We ask whether episodic short-term recognition presupposes that objects have been encoded into capacity-limited visual working memory (VWM), which retains visual information for report. Alternatively, it could rely on the activation of visual features or categories that occurs before encoding into VWM. We assessed the dependence of episodic short-term recognition on VWM by a new paradigm combining letter report and probe recognition. Participants viewed displays of 10 letters and reported as many as possible after a retention interval (whole report). Next, participants viewed a probe letter and indicated whether it had been one of the 10 letters (probe recognition). In Experiment 1, probe recognition was more accurate for letters that had been encoded into VWM (reported letters) compared with non-encoded letters (non-reported letters). Interestingly, those letters that participants reported in their whole report had been near to one another within the letter displays. This suggests that the encoding into VWM proceeded in a spatially clustered manner. In Experiment 2, participants reported only one of 10 letters (partial report) and probes either referred to this letter, to letters that had been near to it, or far from it. Probe recognition was more accurate for near than for far letters, although none of these letters had to be reported. These findings indicate that episodic short-term recognition is constrained to a small number of simultaneously presented objects that have been encoded into VWM.

Episodic Short-Term Recognition Requires Encoding into Visual Working Memory: Evidence from Probe Recognition after Letter Report

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Christian H. Poth

2016-09-01

Full Text Available Human vision is organized in discrete processing episodes (e.g. eye fixations or task-steps. Object information must be transmitted across episodes to enable episodic short-term recognition: recognizing whether a current object has been seen in a previous episode. We ask whether episodic short-term recognition presupposes that objects have been encoded into capacity-limited visual working memory (VWM, which retains visual information for report. Alternatively, it could rely on the activation of visual features or categories that occurs before encoding into VWM. We assessed the dependence of episodic short-term recognition on VWM by a new paradigm combining letter report and probe recognition. Participants viewed displays of ten letters and reported as many as possible after a retention interval (whole report. Next, participants viewed a probe letter and indicated whether it had been one of the ten letters (probe recognition. In Experiment 1, probe recognition was more accurate for letters that had been encoded into VWM (reported letters compared with non-encoded letters (non-reported letters. Interestingly, those letters that participants reported in their whole report had been near to one another within the letter displays. This suggests that the encoding into VWM proceeded in a spatially clustered manner. In Experiment 2 participants reported only one of ten letters (partial report and probes either referred to this letter, to letters that had been near to it, or far from it. Probe recognition was more accurate for near than for far letters, although none of these letters had to be reported. These findings indicate that episodic short-term recognition is constrained to a small number of simultaneously presented objects that have been encoded into VWM.

Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater.

Science.gov (United States)

Potter, Mary C

2016-01-01

Rapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

The sensory components of high-capacity iconic memory and visual working memory.

Science.gov (United States)

Bradley, Claire; Pearson, Joel

2012-01-01

EARLY VISUAL MEMORY CAN BE SPLIT INTO TWO PRIMARY COMPONENTS: a high-capacity, short-lived iconic memory followed by a limited-capacity visual working memory that can last many seconds. Whereas a large number of studies have investigated visual working memory for low-level sensory features, much research on iconic memory has used more "high-level" alphanumeric stimuli such as letters or numbers. These two forms of memory are typically examined separately, despite an intrinsic overlap in their characteristics. Here, we used a purely sensory paradigm to examine visual short-term memory for 10 homogeneous items of three different visual features (color, orientation and motion) across a range of durations from 0 to 6 s. We found that the amount of information stored in iconic memory is smaller for motion than for color or orientation. Performance declined exponentially with longer storage durations and reached chance levels after ∼2 s. Further experiments showed that performance for the 10 items at 1 s was contingent on unperturbed attentional resources. In addition, for orientation stimuli, performance was contingent on the location of stimuli in the visual field, especially for short cue delays. Overall, our results suggest a smooth transition between an automatic, high-capacity, feature-specific sensory-iconic memory, and an effortful "lower-capacity" visual working memory.

Differences in the verbal fluency, working memory and executive functions in alcoholics: Short-term vs. long-term abstainers.

Science.gov (United States)

Nowakowska-Domagała, Katarzyna; Jabłkowska-Górecka, Karolina; Mokros, Łukasz; Koprowicz, Jacek; Pietras, Tadeusz

2017-03-01

The aim of the study was to assess differences in verbal fluency, working memory and executive functions in two subgroups of alcohol-dependent patients, those undergoing short-term abstinence (STA) and those undergoing long-term abstinence (LTA), and to compare the level of cognitive functions in patients after long-term abstinence with healthy subjects. The study group consisted of 106 alcohol-dependent patients (53 immediately after drinking at least 3 days and 53 after at least one-year abstinence). The control group comprised 53 subjects, whose age, sex and education levels matched those of the patients in the experimental group. The dependence intensity was assessed using SADD and MAST scales. The neuropsychological assessment was based on the FAS Test, Stroop Test and TMT A&B Test. The results obtained for alcohol-dependent patients revealed significant disturbances of cognitive functions. Such results indicate the presence of severe frontal cerebral cortex dysfunctions. Frontal cortex dysfunctions affecting the verbal fluency and working memory subsystems and the executive functions also persisted during long-term abstinence periods. No significant correlations between the duration of dependence, quantity of alcohol consumed and efficiency of the working memory and executive functions were observed in alcohol-dependent subjects after short-term or long-term abstinence. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

A concept of psychological work capacity demands: First evaluation in rehabilitation patients with and without mental disorders.

Science.gov (United States)

Muschalla, Beate

2018-01-01

Work capacity demands are a concept to describe which psychological capacities are required in a job. Assessing psychological work capacity demands is of specific importance when mental health problems at work endanger work ability. Exploring psychological work capacity demands is the basis for mental hazard analysis or rehabilitative action, e.g. in terms of work adjustmentOBJECTIVE:This is the first study investigating psychological work capacity demands in rehabilitation patients with and without mental disorders. A structured interview on psychological work capacity demands (Mini-ICF-Work; Muschalla, 2015; Linden et al., 2015) was done with 166 rehabilitation patients of working age. All interviews were done by a state-licensed socio-medically trained psychotherapist. Inter-rater-reliability was assessed by determining agreement in independent co-rating in 65 interviews. For discriminant validity purposes, participants filled in the Short Questionnaire for Work Analysis (KFZA, Prümper et al., 1994). In different professional fields, different psychological work capacity demands were of importance. The Mini-ICF-Work capacity dimensions reflect different aspects than the KFZA. Patients with mental disorders were longer on sick leave and had worse work ability prognosis than patients without mental disorders, although both groups reported similar work capacity demands. Psychological work demands - which are highly relevant for work ability prognosis and work adjustment processes - can be explored and differentiated in terms of psychological capacity demands.

Short-term facilitation may stabilize parametric working memory trace

Directory of Open Access Journals (Sweden)

Vladimir eItskov

2011-10-01

Full Text Available Networks with continuous set of attractors are considered to be a paradigmatic model for parametric working memory, but require fine-tuning of connections and are thus structurally unstable. Here we analyzed the network with ring attractor, where connections are not perfectly tuned and the activity state therefore drifts in the absence of the stabilizing stimulus. We derive an analytical expression for the drift dynamics and conclude that the network cannot function as working memory for a period of several seconds, a typical delay time in monkey memory experiments. We propose that short-term synaptic facilitation in recurrent connections significantly improves the robustness of the model by slowing down the drift of activity bump. Extending the calculation of the drift velocity to network with synaptic facilitation, we conclude that facilitation can slow down the drift by a large factor, rendering the network suitable as a model of working memory.

Increase in short-term memory capacity induced by down-regulating individual theta frequency via transcranial alternating current stimulation.

Science.gov (United States)

Vosskuhl, Johannes; Huster, René J; Herrmann, Christoph S

2015-01-01

Working memory (WM) and short-term memory (STM) supposedly rely on the phase-amplitude coupling (PAC) of neural oscillations in the theta and gamma frequency ranges. The ratio between the individually dominant gamma and theta frequencies is believed to determine an individual's memory capacity. The aim of this study was to establish a causal relationship between the gamma/theta ratio and WM/STM capacity by means of transcranial alternating current stimulation (tACS). To achieve this, tACS was delivered at a frequency below the individual theta frequency. Thereby the individual ratio of gamma to theta frequencies was changed, resulting in an increase of STM capacity. Healthy human participants (N = 33) were allocated to two groups, one receiving verum tACS, the other underwent a sham control protocol. The electroencephalogram (EEG) was measured before stimulation and analyzed with regard to the properties of PAC between theta and gamma frequencies to determine individual stimulation frequencies. After stimulation, EEG was recorded again in order to find after-effects of tACS in the oscillatory features of the EEG. Measures of STM and WM were obtained before, during and after stimulation. Frequency spectra and behavioral data were compared between groups and different measurement phases. The tACS- but not the sham stimulated group showed an increase in STM capacity during stimulation. WM was not affected in either groups. An increase in task-related theta amplitude after stimulation was observed only for the tACS group. These augmented theta amplitudes indicated that the manipulation of individual theta frequencies was successful and caused the increase in STM capacity.

Short-term memory and dual task performance

Science.gov (United States)

Regan, J. E.

1982-01-01

Two hypotheses concerning the way in which short-term memory interacts with another task in a dual task situation are considered. It is noted that when two tasks are combined, the activity of controlling and organizing performance on both tasks simultaneously may compete with either task for a resource; this resource may be space in a central mechanism or general processing capacity or it may be some task-specific resource. If a special relationship exists between short-term memory and control, especially if there is an identity relationship between short-term and a central controlling mechanism, then short-term memory performance should show a decrement in a dual task situation. Even if short-term memory does not have any particular identity with a controlling mechanism, but both tasks draw on some common resource or resources, then a tradeoff between the two tasks in allocating resources is possible and could be reflected in performance. The persistent concurrence cost in memory performance in these experiments suggests that short-term memory may have a unique status in the information processing system.

Visual Short-Term Memory Complexity

DEFF Research Database (Denmark)

Sørensen, Thomas Alrik

Several recent studies have explored the nature and limits of visual short-term memory (VSTM) (e.g. Luck & Vogel, 1997). A general VSTM capacity limit of about 3 to 4 letters has been found, thus confirming results from earlier studies (e.g. Cattell, 1885; Sperling, 1960). However, Alvarez...

Qualitative similarities in the visual short-term memory of pigeons and people

OpenAIRE

Gibson, Brett; Wasserman, Edward; Luck, Steven J.

2011-01-01

Visual short-term memory plays a key role in guiding behavior, and individual differences in visual short-term memory capacity are strongly predictive of higher cognitive abilities. To provide a broader evolutionary context for understanding this memory system, we directly compared the behavior of pigeons and humans on a change detection task. Although pigeons had a lower storage capacity and a higher lapse rate than humans, both species stored multiple items in short-term memory and conforme...

Qualitative similarities in the visual short-term memory of pigeons and people.

Science.gov (United States)

Gibson, Brett; Wasserman, Edward; Luck, Steven J

2011-10-01

Visual short-term memory plays a key role in guiding behavior, and individual differences in visual short-term memory capacity are strongly predictive of higher cognitive abilities. To provide a broader evolutionary context for understanding this memory system, we directly compared the behavior of pigeons and humans on a change detection task. Although pigeons had a lower storage capacity and a higher lapse rate than humans, both species stored multiple items in short-term memory and conformed to the same basic performance model. Thus, despite their very different evolutionary histories and neural architectures, pigeons and humans have functionally similar visual short-term memory systems, suggesting that the functional properties of visual short-term memory are subject to similar selective pressures across these distant species.

Short-term cessation of sex work and injection drug use: evidence from a recurrent event survival analysis.

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Gaines, Tommi L; Urada, Lianne A; Martinez, Gustavo; Goldenberg, Shira M; Rangel, Gudelia; Reed, Elizabeth; Patterson, Thomas L; Strathdee, Steffanie A

2015-06-01

This study quantitatively examined the prevalence and correlates of short-term sex work cessation among female sex workers who inject drugs (FSW-IDUs) and determined whether injection drug use was independently associated with cessation. We used data from FSW-IDUs (n=467) enrolled into an intervention designed to increase condom use and decrease sharing of injection equipment but was not designed to promote sex work cessation. We applied a survival analysis that accounted for quit-re-entry patterns of sex work over 1-year stratified by city, Tijuana and Ciudad Juarez, Mexico. Overall, 55% of participants stopped sex work at least once during follow-up. Controlling for other characteristics and intervention assignment, injection drug use was inversely associated with short-term sex work cessation in both cities. In Ciudad Juarez, women receiving drug treatment during follow-up had a 2-fold increase in the hazard of stopping sex work. In both cities, income from sources other than sex work, police interactions and healthcare access were independently and significantly associated with shorter-term cessation. Short-term sex work cessation was significantly affected by injection drug use. Expanded drug treatment and counseling coupled with supportive services such as relapse prevention, job training, and provision of alternate employment opportunities may promote longer-term cessation among women motivated to leave the sex industry. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of emotional content on working memory capacity.

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Garrison, Katie E; Schmeichel, Brandon J

2018-02-13

Emotional events tend to be remembered better than neutral events, but emotional states and stimuli may also interfere with cognitive processes that underlie memory performance. The current study investigated the effects of emotional content on working memory capacity (WMC), which involves both short term storage and executive attention control. We tested competing hypotheses in a preregistered experiment (N = 297). The emotional enhancement hypothesis predicts that emotional stimuli attract attention and additional processing resources relative to neutral stimuli, thereby making it easier to encode and store emotional information in WMC. The emotional impairment hypothesis, by contrast, predicts that emotional stimuli interfere with attention control and the active maintenance of information in working memory. Participants completed a common measure of WMC (the operation span task; Turner, M. L., & Engle, R. W. [1989]. Is working memory capacity task dependent? Journal of Memory and Language, 28, 127-154) that included either emotional or neutral words. Results revealed that WMC was reduced for emotional words relative to neutral words, consistent with the emotional impairment hypothesis.

Pigeon visual short-term memory directly compared to primates.

Science.gov (United States)

Wright, Anthony A; Elmore, L Caitlin

2016-02-01

Three pigeons were trained to remember arrays of 2-6 colored squares and detect which of two squares had changed color to test their visual short-term memory. Procedures (e.g., stimuli, displays, viewing times, delays) were similar to those used to test monkeys and humans. Following extensive training, pigeons performed slightly better than similarly trained monkeys, but both animal species were considerably less accurate than humans with the same array sizes (2, 4 and 6 items). Pigeons and monkeys showed calculated memory capacities of one item or less, whereas humans showed a memory capacity of 2.5 items. Despite the differences in calculated memory capacities, the pigeons' memory results, like those from monkeys and humans, were all well characterized by an inverse power-law function fit to d' values for the five display sizes. This characterization provides a simple, straightforward summary of the fundamental processing of visual short-term memory (how visual short-term memory declines with memory load) that emphasizes species similarities based upon similar functional relationships. By closely matching pigeon testing parameters to those of monkeys and humans, these similar functional relationships suggest similar underlying processes of visual short-term memory in pigeons, monkeys and humans. Copyright © 2015 Elsevier B.V. All rights reserved.

The sensory components of high-capacity iconic memory and visual working memory

Directory of Open Access Journals (Sweden)

Claire eBradley

2012-09-01

Full Text Available Early visual memory can be split into two primary components: a high-capacity, short-lived iconic memory followed by a limited-capacity visual working memory that can last many seconds. Whereas a large number of studies have investigated visual working memory for low-level sensory features, much research on iconic memory has used more high-level alphanumeric stimuli such as letters or numbers. These two forms of memory are typically examined separately, despite an intrinsic overlap in their characteristics. Here, we used a purely sensory paradigm to examine visual short-term memory for 10 homogeneous items of 3 different visual features (colour, orientation and motion across a range of durations from 0 to 6 seconds. We found that the amount of information stored in iconic memory is smaller for motion than for colour or orientation. Performance declined exponentially with longer storage durations and reached chance levels after ~2 seconds. Further experiments showed that performance for the 10 items at 1 second was contingent on unperturbed attentional resources. In addition, for orientation stimuli, performance was contingent on the location of stimuli in the visual field, especially for short cue delays. Overall, our results suggest a smooth transition between an automatic, high-capacity, feature-specific sensory-iconic memory and an effortful ‘lower-capacity’ visual working memory.

Short-Term Contract Work in Adult Education (I) and (II).

Science.gov (United States)

Hall, Dorothea; McMath, Patricia

1986-01-01

This two-part article discusses short-term project contracts for adult education staff. Part one covers implications of this trend for the service and for the staff involved. Part two looks at short-term contracts from the management viewpoint. (CH)

Maternal scaffolding in a disadvantaged global context: The influence of working memory and cognitive capacities.

Science.gov (United States)

Obradović, Jelena; Portilla, Ximena A; Tirado-Strayer, Nicole; Siyal, Saima; Rasheed, Muneera A; Yousafzai, Aisha K

2017-03-01

The current study focuses on maternal cognitive capacities as determinants of parenting in a highly disadvantaged global context, where children's experiences at home are often the 1st and only opportunity for learning and intellectual growth. In a large sample of 1,291 biological mothers of preschool-aged children in rural Pakistan, we examined the unique association of maternal working memory skills (independent of related cognitive capacities) with cognitively stimulating parenting behaviors. Path analysis revealed that directly assessed working memory, short-term memory, and verbal intelligence independently predicted greater levels of observed maternal scaffolding behaviors. Mothers from poorer families demonstrated lower levels of working memory, short-term memory, and verbal intelligence. However, mothers' participation in an early childhood parenting intervention that ended 2 years prior to this study contributed to greater levels of working memory skills and verbal intelligence. Further, all 3 domains of maternal cognitive capacity mediated the effect of family economic resources on maternal scaffolding, and verbal intelligence also mediated the effect of early parenting intervention exposure on maternal scaffolding. The study demonstrates the unique relevance of maternal working memory for scaffolding behaviors that required continuously monitoring the child's engagement, providing assistance, and minimizing external distractions. These results highlight the importance of directly targeting maternal cognitive capacities in poor women with little or no formal education, using a 2-generation intervention approach that includes activities known to promote parental executive functioning and literacy. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

An integrated unscented kalman filter and relevance vector regression approach for lithium-ion battery remaining useful life and short-term capacity prediction

International Nuclear Information System (INIS)

Zheng, Xiujuan; Fang, Huajing

2015-01-01

The gradual decreasing capacity of lithium-ion batteries can serve as a health indicator for tracking the degradation of lithium-ion batteries. It is important to predict the capacity of a lithium-ion battery for future cycles to assess its health condition and remaining useful life (RUL). In this paper, a novel method is developed using unscented Kalman filter (UKF) with relevance vector regression (RVR) and applied to RUL and short-term capacity prediction of batteries. A RVR model is employed as a nonlinear time-series prediction model to predict the UKF future residuals which otherwise remain zero during the prediction period. Taking the prediction step into account, the predictive value through the RVR method and the latest real residual value constitute the future evolution of the residuals with a time-varying weighting scheme. Next, the future residuals are utilized by UKF to recursively estimate the battery parameters for predicting RUL and short-term capacity. Finally, the performance of the proposed method is validated and compared to other predictors with the experimental data. According to the experimental and analysis results, the proposed approach has high reliability and prediction accuracy, which can be applied to battery monitoring and prognostics, as well as generalized to other prognostic applications. - Highlights: • An integrated method is proposed for RUL prediction as well as short-term capacity prediction. • Relevance vector regression model is employed as a nonlinear time-series prediction model. • Unscented Kalman filter is used to recursively update the states for battery model parameters during the prediction. • A time-varying weighting scheme is utilized to improve the accuracy of the RUL prediction. • The proposed method demonstrates high reliability and prediction accuracy.

A Spiking Working Memory Model Based on Hebbian Short-Term Potentiation

Science.gov (United States)

Fiebig, Florian

2017-01-01

A dominant theory of working memory (WM), referred to as the persistent activity hypothesis, holds that recurrently connected neural networks, presumably located in the prefrontal cortex, encode and maintain WM memory items through sustained elevated activity. Reexamination of experimental data has shown that prefrontal cortex activity in single units during delay periods is much more variable than predicted by such a theory and associated computational models. Alternative models of WM maintenance based on synaptic plasticity, such as short-term nonassociative (non-Hebbian) synaptic facilitation, have been suggested but cannot account for encoding of novel associations. Here we test the hypothesis that a recently identified fast-expressing form of Hebbian synaptic plasticity (associative short-term potentiation) is a possible mechanism for WM encoding and maintenance. Our simulations using a spiking neural network model of cortex reproduce a range of cognitive memory effects in the classical multi-item WM task of encoding and immediate free recall of word lists. Memory reactivation in the model occurs in discrete oscillatory bursts rather than as sustained activity. We relate dynamic network activity as well as key synaptic characteristics to electrophysiological measurements. Our findings support the hypothesis that fast Hebbian short-term potentiation is a key WM mechanism. SIGNIFICANCE STATEMENT Working memory (WM) is a key component of cognition. Hypotheses about the neural mechanism behind WM are currently under revision. Reflecting recent findings of fast Hebbian synaptic plasticity in cortex, we test whether a cortical spiking neural network model with such a mechanism can learn a multi-item WM task (word list learning). We show that our model can reproduce human cognitive phenomena and achieve comparable memory performance in both free and cued recall while being simultaneously compatible with experimental data on structure, connectivity, and

Ordered short-term memory differs in signers and speakers: Implications for models of short-term memory

OpenAIRE

Bavelier, Daphne; Newport, Elissa L.; Hall, Matt; Supalla, Ted; Boutla, Mrim

2008-01-01

Capacity limits in linguistic short-term memory (STM) are typically measured with forward span tasks in which participants are asked to recall lists of words in the order presented. Using such tasks, native signers of American Sign Language (ASL) exhibit smaller spans than native speakers (Boutla, Supalla, Newport, & Bavelier, 2004). Here, we test the hypothesis that this population difference reflects differences in the way speakers and signers maintain temporal order information in short-te...

Identifying Early Links between Temperament, Short-Term and Working Memory in Preschoolers

Science.gov (United States)

Visu-Petra, Laura; Cheie, Lavinia; Câmpan, Maria; Scutelnicu, Ioana; Benga, Oana

2018-01-01

The present study aimed to investigate early interrelationships between temperament, short-term memory (STM) and working memory (WM), while also relating them to incipient anxious traits in a sample of 4-7-year-olds. Preschoolers were evaluated using verbal and visuospatial STM and WM tasks, while parental reports were used to assess children's…

Increase in short-term memory capacity induced by down-regulating individual theta frequency via transcranial alternating current stimulation

Directory of Open Access Journals (Sweden)

Johannes eVosskuhl

2015-05-01

Full Text Available Working memory (WM and short-term memory (STM supposedly rely on the phase-amplitude coupling of neural oscillations in the theta and gamma frequency ranges. The ratio between the individually dominant gamma and theta frequencies is believed to determine an individual’s memory capacity. The aim of this study was to establish a causal relationship between the gamma/theta ratio and WM/STM capacity by means of transcranial alternating current stimulation (tACS. To achieve this, tACS was delivered at a frequency below the individual theta frequency. Thereby the individual ratio of gamma to theta frequencies was changed, resulting in an increase of STM capacity. Healthy human participants (N=33 were allocated to two groups, one receiving verum tACS, the other underwent a sham control protocol. The electroencephalogram (EEG was measured before stimulation and analyzed with regard to the properties of phase-amplitude coupling between theta and gamma frequencies to determine individual stimulation frequencies. After stimulation, EEG was recorded again in order to find after-effects of tACS in the oscillatory features of the EEG. Measures of STM and WM were obtained before, during and after stimulation. Frequency spectra and behavioral data were compared between groups and different measurement phases. The tACS- but not the sham stimulated group showed an increase in STM capacity during stimulation. WM was not affected in either groups. An increase in task-related theta amplitude after stimulation was observed only for the tACS group. These augmented theta amplitudes indicated that the manipulation of individual theta frequencies was successful and caused the increase in STM capacity.

Geopathic stress zones: short-term effects on work performance and well-being?

Science.gov (United States)

Augner, Christoph; Hacker, Gerhard W; Jekel, Ilse

2010-06-01

The aim of the study was to evaluate whether two different locations in the same room as tested by dowsers ("geopathic stress zone" [GSZ] versus "more neutral zone" [NZ]) would show significant short-term effects on work performance and well-being. It was also tested whether a device reported to "neutralize" GSZ would influence results obtained with the specific setup used in this study. This was a blinded, randomized, short-term laboratory experiment using a within-subject design. The study was conducted in the laboratory of the Research Institute for Frontier Questions of Medicine and Biotechnology at Salzburg Federal Hospital. The subjects were 26 persons, aged 20-57. Participants had to accomplish reaction tasks during three different conditions: GSZ, NZ, and GSZ with a device reported to "neutralize" GSZ. These conditions were counterbalanced into six different sequences and randomized to the subjects. At the end of each condition, a standardized well-being questionnaire had to be completed. Dependent variables were reactive stress tolerance (reaction time, timely right answers, right answers, false answers, left out) and well-being (described by six adjectives). No location-dependent effects on performance during reactive stress tolerance test were seen. For well-being, analysis of variance revealed a trend (p = 0.07) and showed significantly poorer well-being during the GSZ condition compared to NZ (p = 0.01). This study shows that well-being can be location dependent and that this might be caused by a so-called GSZ. However, in our short-term experiment, factors of work performance tested remained unaffected.

Working memory, long-term memory, and medial temporal lobe function

Science.gov (United States)

Jeneson, Annette; Squire, Larry R.

2012-01-01

Early studies of memory-impaired patients with medial temporal lobe (MTL) damage led to the view that the hippocampus and related MTL structures are involved in the formation of long-term memory and that immediate memory and working memory are independent of these structures. This traditional idea has recently been revisited. Impaired performance in patients with MTL lesions on tasks with short retention intervals, or no retention interval, and neuroimaging findings with similar tasks have been interpreted to mean that the MTL is sometimes needed for working memory and possibly even for visual perception itself. We present a reappraisal of this interpretation. Our main conclusion is that, if the material to be learned exceeds working memory capacity, if the material is difficult to rehearse, or if attention is diverted, performance depends on long-term memory even when the retention interval is brief. This fundamental notion is better captured by the terms subspan memory and supraspan memory than by the terms short-term memory and long-term memory. We propose methods for determining when performance on short-delay tasks must depend on long-term (supraspan) memory and suggest that MTL lesions impair performance only when immediate memory and working memory are insufficient to support performance. In neuroimaging studies, MTL activity during encoding is influenced by the memory load and correlates positively with long-term retention of the material that was presented. The most parsimonious and consistent interpretation of all the data is that subspan memoranda are supported by immediate memory and working memory and are independent of the MTL. PMID:22180053

Impaired Verbal Short-Term Memory in down Syndrome Reflects a Capacity Limitation Rather than Atypically Rapid Forgetting

Science.gov (United States)

M. Purser, H.R.; Jarrold, C.

2005-01-01

Individuals with Down syndrome suffer from relatively poor verbal short-term memory. Recent work has indicated that this deficit is not caused by problems of audition, speech, or articulatory rehearsal within the phonological loop component of Baddeley and Hitch's working memory model. Given this, two experiments were conducted to investigate…

The short- and long-term consequences of directed forgetting in a working memory task.

Science.gov (United States)

Festini, Sara B; Reuter-Lorenz, Patricia A

2013-01-01

Directed forgetting requires the voluntary control of memory. Whereas many studies have examined directed forgetting in long-term memory (LTM), the mechanisms and effects of directed forgetting within working memory (WM) are less well understood. The current study tests how directed forgetting instructions delivered in a WM task influence veridical memory, as well as false memory, over the short and long term. In a modified item recognition task Experiment 1 tested WM only and demonstrated that directed forgetting reduces false recognition errors and semantic interference. Experiment 2 replicated these WM effects and used a surprise LTM recognition test to assess the long-term effects of directed forgetting in WM. Long-term veridical memory for to-be-remembered lists was better than memory for to-be-forgotten lists-the directed forgetting effect. Moreover, fewer false memories emerged for to-be-forgotten information than for to-be-remembered information in LTM as well. These results indicate that directed forgetting during WM reduces semantic processing of to-be-forgotten lists over the short and long term. Implications for theories of false memory and the mechanisms of directed forgetting within working memory are discussed.

A Spiking Working Memory Model Based on Hebbian Short-Term Potentiation.

Science.gov (United States)

Fiebig, Florian; Lansner, Anders

2017-01-04

A dominant theory of working memory (WM), referred to as the persistent activity hypothesis, holds that recurrently connected neural networks, presumably located in the prefrontal cortex, encode and maintain WM memory items through sustained elevated activity. Reexamination of experimental data has shown that prefrontal cortex activity in single units during delay periods is much more variable than predicted by such a theory and associated computational models. Alternative models of WM maintenance based on synaptic plasticity, such as short-term nonassociative (non-Hebbian) synaptic facilitation, have been suggested but cannot account for encoding of novel associations. Here we test the hypothesis that a recently identified fast-expressing form of Hebbian synaptic plasticity (associative short-term potentiation) is a possible mechanism for WM encoding and maintenance. Our simulations using a spiking neural network model of cortex reproduce a range of cognitive memory effects in the classical multi-item WM task of encoding and immediate free recall of word lists. Memory reactivation in the model occurs in discrete oscillatory bursts rather than as sustained activity. We relate dynamic network activity as well as key synaptic characteristics to electrophysiological measurements. Our findings support the hypothesis that fast Hebbian short-term potentiation is a key WM mechanism. Working memory (WM) is a key component of cognition. Hypotheses about the neural mechanism behind WM are currently under revision. Reflecting recent findings of fast Hebbian synaptic plasticity in cortex, we test whether a cortical spiking neural network model with such a mechanism can learn a multi-item WM task (word list learning). We show that our model can reproduce human cognitive phenomena and achieve comparable memory performance in both free and cued recall while being simultaneously compatible with experimental data on structure, connectivity, and neurophysiology of the underlying

Ordered Short-Term Memory Differs in Signers and Speakers: Implications for Models of Short-Term Memory

Science.gov (United States)

Bavelier, Daphne; Newport, Elissa L.; Hall, Matt; Supalla, Ted; Boutla, Mrim

2008-01-01

Capacity limits in linguistic short-term memory (STM) are typically measured with forward span tasks in which participants are asked to recall lists of words in the order presented. Using such tasks, native signers of American Sign Language (ASL) exhibit smaller spans than native speakers ([Boutla, M., Supalla, T., Newport, E. L., & Bavelier, D.…

Worrying Thoughts Limit Working Memory Capacity in Math Anxiety.

Science.gov (United States)

Shi, Zhan; Liu, Peiru

2016-01-01

Sixty-one high-math-anxious persons and sixty-one low-math-anxious persons completed a modified working memory capacity task, designed to measure working memory capacity under a dysfunctional math-related context and working memory capacity under a valence-neutral context. Participants were required to perform simple tasks with emotionally benign material (i.e., lists of letters) over short intervals while simultaneously reading and making judgments about sentences describing dysfunctional math-related thoughts or sentences describing emotionally-neutral facts about the world. Working memory capacity for letters under the dysfunctional math-related context, relative to working memory capacity performance under the valence-neutral context, was poorer overall in the high-math-anxious group compared with the low-math-anxious group. The findings show a particular difficulty employing working memory in math-related contexts in high-math-anxious participants. Theories that can provide reasonable interpretations for these findings and interventions that can reduce anxiety-induced worrying intrusive thoughts or improve working memory capacity for math anxiety are discussed.

Short-term effects of implemented high intensity shoulder elevation during computer work

DEFF Research Database (Denmark)

Larsen, Mette K.; Samani, Afshin; Madeleine, Pascal

2009-01-01

computer work to prevent neck-shoulder pain may be possible without affecting the working routines. However, the unexpected reduction in clavicular trapezius rest during a pause with preceding high intensity contraction requires further investigation before high intensity shoulder elevations can......BACKGROUND: Work-site strength training sessions are shown effective to prevent and reduce neck-shoulder pain in computer workers, but difficult to integrate in normal working routines. A solution for avoiding neck-shoulder pain during computer work may be to implement high intensity voluntary...... contractions during the computer work. However, it is unknown how this may influence productivity, rate of perceived exertion (RPE) as well as activity and rest of neck-shoulder muscles during computer work. The aim of this study was to investigate short-term effects of a high intensity contraction...

Visual working memory capacity and proactive interference.

Science.gov (United States)

Hartshorne, Joshua K

2008-07-23

Visual working memory capacity is extremely limited and appears to be relatively immune to practice effects or the use of explicit strategies. The recent discovery that visual working memory tasks, like verbal working memory tasks, are subject to proactive interference, coupled with the fact that typical visual working memory tasks are particularly conducive to proactive interference, suggests that visual working memory capacity may be systematically under-estimated. Working memory capacity was probed behaviorally in adult humans both in laboratory settings and via the Internet. Several experiments show that although the effect of proactive interference on visual working memory is significant and can last over several trials, it only changes the capacity estimate by about 15%. This study further confirms the sharp limitations on visual working memory capacity, both in absolute terms and relative to verbal working memory. It is suggested that future research take these limitations into account in understanding differences across a variety of tasks between human adults, prelinguistic infants and nonlinguistic animals.

Resuming growth in Latin America: short and long term policies

Directory of Open Access Journals (Sweden)

Julio Lopez G.

2008-09-01

Full Text Available The authors of this paper assert that the paralysis of the state generated by the crises of the 1970s and 1980s deprived the economies of the region of an important lever to resume and sustain growth. They thus maintain that to overcome stagnation it will be necessary to reconstruct the state's capacity to implement pro-growth policies. Following Keynes and Kalecki's ideas, but also classical development economists, the authors argue, first, that short-term macroeconomic policies, to reduce unemployment and to increase the degree of capacity utilization, should be used to promote the generation of profits to firms and to wake up entrepreneurs' animal spirits. Short-term expansionary policies should be coupled with measures to improve competitiveness and avoid balance of payments problems. They also claim that alternatives to the liberal programme will fail unless a pro-growth strategy is adopted which includes both short- and long-term policies. They thus propose that long-term policies must complete the package, signaling: a sustained increases of effective demand in the future; and b investment priorities to ensure that capacities will be created in strategic sectors and branches of the economy.

Short-Term Forecasting of Loads and Wind Power for Latvian Power System: Accuracy and Capacity of the Developed Tools

Directory of Open Access Journals (Sweden)

Radziukynas V.

2016-04-01

Full Text Available The paper analyses the performance results of the recently developed short-term forecasting suit for the Latvian power system. The system load and wind power are forecasted using ANN and ARIMA models, respectively, and the forecasting accuracy is evaluated in terms of errors, mean absolute errors and mean absolute percentage errors. The investigation of influence of additional input variables on load forecasting errors is performed. The interplay of hourly loads and wind power forecasting errors is also evaluated for the Latvian power system with historical loads (the year 2011 and planned wind power capacities (the year 2023.

Short-Term Forecasting of Loads and Wind Power for Latvian Power System: Accuracy and Capacity of the Developed Tools

Science.gov (United States)

Radziukynas, V.; Klementavičius, A.

2016-04-01

The paper analyses the performance results of the recently developed short-term forecasting suit for the Latvian power system. The system load and wind power are forecasted using ANN and ARIMA models, respectively, and the forecasting accuracy is evaluated in terms of errors, mean absolute errors and mean absolute percentage errors. The investigation of influence of additional input variables on load forecasting errors is performed. The interplay of hourly loads and wind power forecasting errors is also evaluated for the Latvian power system with historical loads (the year 2011) and planned wind power capacities (the year 2023).

Short-term effects of night shift work on breast cancer risk

DEFF Research Database (Denmark)

Vistisen, H. T.; Garde, A. H.; Frydenberg, M.

2017-01-01

.80-1.01] was observed for workers ever working night shifts during the follow-up period compared with workers only working day shifts after adjustment for age, age at first child, parity, family history of breast or ovarian cancer, sex hormones, medications related to alcoholism, family educational level, mammography......Objectives: The objective was to examine if night shift work is a short-term risk factor for breast cancer, including combined estrogen receptor (ER) and human epidermal growth factor 2 (HER2) breast cancer subtypes. Methods: The cohort comprised 155 540 public sector female workers in Denmark who...... were followed from 2007-2012. Day-to-day work-hour information was available from payroll registers and 1245 incident cases of breast cancer were identified in national cancer registries together with receptor subtype information. Results: A rate ratio (RR) of 0.90 [95% confidence interval (95% CI) 0...

INCAP - Applying short-term flexibility to control inventories

OpenAIRE

Lödding , Hermann; Lohmann , Steffen

2011-01-01

Abstract Inventory Based Capacity Control (INCAP) is a very simple method that allows inventory levels to be effectively controlled by using short-term capacity flexibility in make-to-stock settings. Moreover, INCAP can be used for finished goods inventories as well as for semi-finished goods inventories. The basic idea is to define upper and lower inventory limits and to adjust capacities if the inventory level reaches either limit. Should the inventory fall below the lower limit,...

Worrying Thoughts Limit Working Memory Capacity in Math Anxiety.

Directory of Open Access Journals (Sweden)

Zhan Shi

Full Text Available Sixty-one high-math-anxious persons and sixty-one low-math-anxious persons completed a modified working memory capacity task, designed to measure working memory capacity under a dysfunctional math-related context and working memory capacity under a valence-neutral context. Participants were required to perform simple tasks with emotionally benign material (i.e., lists of letters over short intervals while simultaneously reading and making judgments about sentences describing dysfunctional math-related thoughts or sentences describing emotionally-neutral facts about the world. Working memory capacity for letters under the dysfunctional math-related context, relative to working memory capacity performance under the valence-neutral context, was poorer overall in the high-math-anxious group compared with the low-math-anxious group. The findings show a particular difficulty employing working memory in math-related contexts in high-math-anxious participants. Theories that can provide reasonable interpretations for these findings and interventions that can reduce anxiety-induced worrying intrusive thoughts or improve working memory capacity for math anxiety are discussed.

Long vs. short-term energy storage:sensitivity analysis.

Energy Technology Data Exchange (ETDEWEB)

Schoenung, Susan M. (Longitude 122 West, Inc., Menlo Park, CA); Hassenzahl, William V. (,Advanced Energy Analysis, Piedmont, CA)

2007-07-01

This report extends earlier work to characterize long-duration and short-duration energy storage technologies, primarily on the basis of life-cycle cost, and to investigate sensitivities to various input assumptions. Another technology--asymmetric lead-carbon capacitors--has also been added. Energy storage technologies are examined for three application categories--bulk energy storage, distributed generation, and power quality--with significant variations in discharge time and storage capacity. Sensitivity analyses include cost of electricity and natural gas, and system life, which impacts replacement costs and capital carrying charges. Results are presented in terms of annual cost, $/kW-yr. A major variable affecting system cost is hours of storage available for discharge.

Measuring Short-term Energy Security

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-07-01

Ensuring energy security has been at the centre of the IEA mission since its inception, following the oil crises of the early 1970s. While the security of oil supplies remains important, contemporary energy security policies must address all energy sources and cover a comprehensive range of natural, economic and political risks that affect energy sources, infrastructures and services. In response to this challenge, the IEA is currently developing a Model Of Short-term Energy Security (MOSES) to evaluate the energy security risks and resilience capacities of its member countries. The current version of MOSES covers short-term security of supply for primary energy sources and secondary fuels among IEA countries. It also lays the foundation for analysis of vulnerabilities of electricity and end-use energy sectors. MOSES contains a novel approach to analysing energy security, which can be used to identify energy security priorities, as a starting point for national energy security assessments and to track the evolution of a country's energy security profile. By grouping together countries with similar 'energy security profiles', MOSES depicts the energy security landscape of IEA countries. By extending the MOSES methodology to electricity security and energy services in the future, the IEA aims to develop a comprehensive policy-relevant perspective on global energy security. This Brochure provides and overview of the analysis and results. Readers interested in an in-depth discussion of methodology are referred to the MOSES Working Paper.

Visual working memory capacity and proactive interference.

Directory of Open Access Journals (Sweden)

Joshua K Hartshorne

Full Text Available BACKGROUND: Visual working memory capacity is extremely limited and appears to be relatively immune to practice effects or the use of explicit strategies. The recent discovery that visual working memory tasks, like verbal working memory tasks, are subject to proactive interference, coupled with the fact that typical visual working memory tasks are particularly conducive to proactive interference, suggests that visual working memory capacity may be systematically under-estimated. METHODOLOGY/PRINCIPAL FINDINGS: Working memory capacity was probed behaviorally in adult humans both in laboratory settings and via the Internet. Several experiments show that although the effect of proactive interference on visual working memory is significant and can last over several trials, it only changes the capacity estimate by about 15%. CONCLUSIONS/SIGNIFICANCE: This study further confirms the sharp limitations on visual working memory capacity, both in absolute terms and relative to verbal working memory. It is suggested that future research take these limitations into account in understanding differences across a variety of tasks between human adults, prelinguistic infants and nonlinguistic animals.

Do Children with Phonological Delay Have Phonological Short-Term and Phonological Working Memory Deficits?

Science.gov (United States)

Waring, Rebecca; Eadie, Patricia; Liow, Susan Rickard; Dodd, Barbara

2017-01-01

While little is known about why children make speech errors, it has been hypothesized that cognitive-linguistic factors may underlie phonological speech sound disorders. This study compared the phonological short-term and phonological working memory abilities (using immediate memory tasks) and receptive vocabulary size of 14 monolingual preschool…

Short-term LNG-markets

International Nuclear Information System (INIS)

Eldegard, Tom; Lund, Arne-Christian; Miltersen, Kristian; Rud, Linda

2005-01-01

The global Liquefied Natural Gas (LNG) industry has experienced substantial growth in the past decades. In the traditional trade patterns of LNG the product has typically been handled within a dedicated chain of plants and vessels fully committed by long term contracts or common ownership, providing risk sharing of large investments in a non-liquid market. Increasing gas prices and substantial cost reductions in all parts of the LNG chain have made LNG projects viable even if only part of the capacity is secured by long-term contracts, opening for more flexible trade of the remainder. Increasing gas demand, especially in power generation, combined with cost reductions in the cost of LNG terminals, open new markets for LNG. For the LNG supplier, the flexibility of shifting volumes between regions represents an additional value. International trade in LNG has been increasing, now accounting for more than one fifth of the world's cross-border gas trade. Despite traditional vertical chain bonds, increased flexibility has contributed in fact to an increasing LNG spot trade, representing 8% of global trade in 2002. The focus of this paper is on the development of global short-term LNG markets, and their role with respect to efficiency and security of supply in European gas markets. Arbitrage opportunities arising from price differences between regional markets (such as North America versus Europe) are important impetuses for flexible short-term trade. However, the short-term LNG trade may suffer from problems related to market access, e.g. limited access to terminals and regulatory issues, as well as rigidities connected to vertical binding within the LNG chain. Important issues related to the role of short-term LNG-trade in the European gas market are: Competition, flexibility in meeting peak demand, security of supply and consequences of differences in pricing policies (oil-linked prices in Europe and spot market prices in North America). (Author)

The Role of Short-term Consolidation in Memory Persistence

OpenAIRE

Timothy J. Ricker

2015-01-01

Short-term memory, often described as working memory, is one of the most fundamental information processing systems of the human brain. Short-term memory function is necessary for language, spatial navigation, problem solving, and many other daily activities. Given its importance to cognitive function, understanding the architecture of short-term memory is of crucial importance to understanding human behavior. Recent work from several laboratories investigating the entry of information into s...

Task-evoked pupillometry provides a window into the development of short-term memory capacity.

Science.gov (United States)

Johnson, Elizabeth L; Miller Singley, Alison T; Peckham, Andrew D; Johnson, Sheri L; Bunge, Silvia A

2014-01-01

The capacity to keep multiple items in short-term memory (STM) improves over childhood and provides the foundation for the development of multiple cognitive abilities. The goal of this study was to measure the extent to which age differences in STM capacity are related to differences in task engagement during encoding. Children (n = 69, mean age = 10.6 years) and adults (n = 54, mean age = 27.5 years) performed two STM tasks: the forward digit span test from the Wechsler Intelligence Scale for Children (WISC) and a novel eyetracking digit span task designed to overload STM capacity. Building on prior research showing that task-evoked pupil dilation can be used as a real-time index of task engagement, we measured changes in pupil dilation while participants encoded long sequences of digits for subsequent recall. As expected, adults outperformed children on both STM tasks. We found similar patterns of pupil dilation while children and adults listened to the first six digits on our STM overload task, after which the adults' pupils continued to dilate and the children's began to constrict, suggesting that the children had reached their cognitive limits and that they had begun to disengage from the task. Indeed, the point at which pupil dilation peaked at encoding was a significant predictor of WISC forward span, and this relationship held even after partialing out recall performance on the STM overload task. These findings indicate that sustained task engagement at encoding is an important component of the development of STM.

Task-evoked pupillometry provides a window into the development of short-term memory capacity

Directory of Open Access Journals (Sweden)

Elizabeth L. Johnson

2014-03-01

Full Text Available The capacity to keep multiple items in short-term memory (STM improves over childhood and provides the foundation for the development of multiple cognitive abilities. The goal of this study was to measure the extent to which age differences in STM capacity are related to differences in task engagement during encoding. Children (n = 69, mean age = 10.5 years and adults (n = 54, mean age = 27.5 years performed two STM tasks: the forward digit span test from the Wechsler Intelligence Scale for Children (WISC and a novel eyetracking digit span task designed to overload STM capacity. Building on prior research showing that task-evoked pupil dilation can be used as a real-time index of task engagement, we measured changes in pupil dilation while participants encoded long sequences of digits for subsequent recall. As expected, adults outperformed children on both STM tasks. We found similar patterns of pupil dilation while children and adults listened to the first six digits on our STM Overload task, after which the adults’ pupils continued to dilate and the children’s began to constrict, suggesting that the children had reached their cognitive limits and that they had begun to disengage attention from the task. Indeed, the point at which pupil dilation peaked at encoding was a significant predictor of WISC forward span, and this relationship held even after partialing out recall performance on the STM Overload task. These findings indicate that sustained task engagement at encoding is an important component of the development of STM.

Task-evoked pupillometry provides a window into the development of short-term memory capacity

Science.gov (United States)

Johnson, Elizabeth L.; Miller Singley, Alison T.; Peckham, Andrew D.; Johnson, Sheri L.; Bunge, Silvia A.

2014-01-01

The capacity to keep multiple items in short-term memory (STM) improves over childhood and provides the foundation for the development of multiple cognitive abilities. The goal of this study was to measure the extent to which age differences in STM capacity are related to differences in task engagement during encoding. Children (n = 69, mean age = 10.6 years) and adults (n = 54, mean age = 27.5 years) performed two STM tasks: the forward digit span test from the Wechsler Intelligence Scale for Children (WISC) and a novel eyetracking digit span task designed to overload STM capacity. Building on prior research showing that task-evoked pupil dilation can be used as a real-time index of task engagement, we measured changes in pupil dilation while participants encoded long sequences of digits for subsequent recall. As expected, adults outperformed children on both STM tasks. We found similar patterns of pupil dilation while children and adults listened to the first six digits on our STM overload task, after which the adults' pupils continued to dilate and the children's began to constrict, suggesting that the children had reached their cognitive limits and that they had begun to disengage from the task. Indeed, the point at which pupil dilation peaked at encoding was a significant predictor of WISC forward span, and this relationship held even after partialing out recall performance on the STM overload task. These findings indicate that sustained task engagement at encoding is an important component of the development of STM. PMID:24659980

Short-Term Memory and Its Biophysical Model

Science.gov (United States)

Wang, Wei; Zhang, Kai; Tang, Xiao-wei

1996-12-01

The capacity of short-term memory has been studied using an integrate-and-fire neuronal network model. It is found that the storage of events depend on the manner of the correlation between the events, and the capacity is dominated by the value of after-depolarization potential. There is a monotonic increasing relationship between the value of after-depolarization potential and the memory numbers. The biophysics relevance of the network model is discussed and different kinds of the information processes are studied too.

Estimated capacity of object files in visual short-term memory is not improved by retrieval cueing.

Science.gov (United States)

Saiki, Jun; Miyatsuji, Hirofumi

2009-03-23

Visual short-term memory (VSTM) has been claimed to maintain three to five feature-bound object representations. Some results showing smaller capacity estimates for feature binding memory have been interpreted as the effects of interference in memory retrieval. However, change-detection tasks may not properly evaluate complex feature-bound representations such as triple conjunctions in VSTM. To understand the general type of feature-bound object representation, evaluation of triple conjunctions is critical. To test whether interference occurs in memory retrieval for complete object file representations in a VSTM task, we cued retrieval in novel paradigms that directly evaluate the memory for triple conjunctions, in comparison with a simple change-detection task. In our multiple object permanence tracking displays, observers monitored for a switch in feature combination between objects during an occlusion period, and we found that a retrieval cue provided no benefit with the triple conjunction tasks, but significant facilitation with the change-detection task, suggesting that low capacity estimates of object file memory in VSTM reflect a limit on maintenance, not retrieval.

TMS over the right precuneus reduces the bilateral field advantage in visual short term memory capacity.

Science.gov (United States)

Kraft, Antje; Dyrholm, Mads; Kehrer, Stefanie; Kaufmann, Christian; Bruening, Jovita; Kathmann, Norbert; Bundesen, Claus; Irlbacher, Kerstin; Brandt, Stephan A

2015-01-01

Several studies have demonstrated a bilateral field advantage (BFA) in early visual attentional processing, that is, enhanced visual processing when stimuli are spread across both visual hemifields. The results are reminiscent of a hemispheric resource model of parallel visual attentional processing, suggesting more attentional resources on an early level of visual processing for bilateral displays [e.g. Sereno AB, Kosslyn SM. Discrimination within and between hemifields: a new constraint on theories of attention. Neuropsychologia 1991;29(7):659-75.]. Several studies have shown that the BFA extends beyond early stages of visual attentional processing, demonstrating that visual short term memory (VSTM) capacity is higher when stimuli are distributed bilaterally rather than unilaterally. Here we examine whether hemisphere-specific resources are also evident on later stages of visual attentional processing. Based on the Theory of Visual Attention (TVA) [Bundesen C. A theory of visual attention. Psychol Rev 1990;97(4):523-47.] we used a whole report paradigm that allows investigating visual attention capacity variability in unilateral and bilateral displays during navigated repetitive transcranial magnetic stimulation (rTMS) of the precuneus region. A robust BFA in VSTM storage capacity was apparent after rTMS over the left precuneus and in the control condition without rTMS. In contrast, the BFA diminished with rTMS over the right precuneus. This finding indicates that the right precuneus plays a causal role in VSTM capacity, particularly in bilateral visual displays. Copyright © 2015 Elsevier Inc. All rights reserved.

Fragile visual short-term memory is an object-based and location-specific store.

Science.gov (United States)

Pinto, Yaïr; Sligte, Ilja G; Shapiro, Kimron L; Lamme, Victor A F

2013-08-01

Fragile visual short-term memory (FM) is a recently discovered form of visual short-term memory. Evidence suggests that it provides rich and high-capacity storage, like iconic memory, yet it exists, without interference, almost as long as visual working memory. In the present study, we sought to unveil the functional underpinnings of this memory storage. We found that FM is only completely erased when the new visual scene appears at the same location and consists of the same objects as the to-be-recalled information. This result has two important implications: First, it shows that FM is an object- and location-specific store, and second, it suggests that FM might be used in everyday life when the presentation of visual information is appropriately designed.

Verbal short-term memory and vocabulary learning in polyglots.

Science.gov (United States)

Papagno, C; Vallar, G

1995-02-01

Polyglot and non-polyglot Italian subjects were given tests assessing verbal (phonological) and visuo-spatial short-term and long-term memory, general intelligence, and vocabulary knowledge in their native language. Polyglots had a superior level of performance in verbal short-term memory tasks (auditory digit span and nonword repetition) and in a paired-associate learning test, which assessed the subjects' ability to acquire new (Russian) words. By contrast, the two groups had comparable performance levels in tasks assessing general intelligence, visuo-spatial short-term memory and learning, and paired-associate learning of Italian words. These findings, which are in line with neuropsychological and developmental evidence, as well as with data from normal subjects, suggest a close relationship between the capacity of phonological memory and the acquisition of foreign languages.

Understanding phonological memory deficits in boys with attention-deficit/hyperactivity disorder (ADHD): dissociation of short-term storage and articulatory rehearsal processes.

Science.gov (United States)

Bolden, Jennifer; Rapport, Mark D; Raiker, Joseph S; Sarver, Dustin E; Kofler, Michael J

2012-08-01

The current study dissociated and examined the two primary components of the phonological working memory subsystem--the short-term store and articulatory rehearsal mechanism--in boys with ADHD (n = 18) relative to typically developing boys (n = 15). Word lists of increasing length (2, 4, and 6 words per trial) were presented to and recalled by children following a brief (3 s) interval to assess their phonological short-term storage capacity. Children's ability to utilize the articulatory rehearsal mechanism to actively maintain information in the phonological short-term store was assessed using word lists at their established memory span but with extended rehearsal times (12 s and 21 s delays). Results indicate that both phonological shortterm storage capacity and articulatory rehearsal are impaired or underdeveloped to a significant extent in boys with ADHD relative to typically developing boys, even after controlling for age, SES, IQ, and reading speed. Larger magnitude deficits, however, were apparent in short-term storage capacity (ES = 1.15 to 1.98) relative to articulatory rehearsal (ES = 0.47 to 1.02). These findings are consistent with previous reports of deficient phonological short-term memory in boys with ADHD, and suggest that future attempts to develop remedial cognitive interventions for children with ADHD will need to include active components that require children to hold increasingly more information over longer time intervals.

Short-term storage evaluation of quality and antioxidant capacity in chestnut-wheat bread.

Science.gov (United States)

Rinaldi, Massimiliano; Paciulli, Maria; Dall'Asta, Chiara; Cirlini, Martina; Chiavaro, Emma

2015-01-01

Bread traditionally made from wheat is now often supplemented with alternative functional ingredients as chestnut flours; no data have been previously published about the staling of chestnut-containing bread. Thus short-term storage (3 days) for chestnut flour-supplemented soft wheat bread is evaluated by means of selected physicochemical properties (i.e. water dynamics, texture, colour, crumb grain characteristic, total antioxidant capacity). Bread prepared with a 20:80 ratio of chestnut:soft wheat flours maintained its moisture content in both crust and crumb. Crumb hardness, after baking, was found to be significantly higher than that of the soft wheat bread; it did not change during storage, whereas it significantly increased in the control bread until the end of the shelf life. The supplemented bread presented a heterogeneous crumb structure, with a significant decrease in the largest pores during shelf life, relative to the shrinkage of crumb grain. The control exhibited a significant redistribution of crumb holes, with a decrease in the smallest grain classes and an increase in the intermediate ones, most likely caused by cell wall thickening. The colour of the crumb remained unaltered in both breads. The crust of the control presented a significant decrease of a* (redness) and that of the supplemented bread exhibited a decrease of b* (yellowness). The antioxidant capacity was detected after day 1 of storage in the chestnut flour bread only. Chestnut flour supplementation could represent a feasible way of producing bread with improved characteristics, not only just after baking but also during shelf life. © 2014 Society of Chemical Industry.

Gummed-up memory: chewing gum impairs short-term recall.

Science.gov (United States)

Kozlov, Michail D; Hughes, Robert W; Jones, Dylan M

2012-01-01

Several studies have suggested that short-term memory is generally improved by chewing gum. However, we report the first studies to show that chewing gum impairs short-term memory for both item order and item identity. Experiment 1 showed that chewing gum reduces serial recall of letter lists. Experiment 2 indicated that chewing does not simply disrupt vocal-articulatory planning required for order retention: Chewing equally impairs a matched task that required retention of list item identity. Experiment 3 demonstrated that manual tapping produces a similar pattern of impairment to that of chewing gum. These results clearly qualify the assertion that chewing gum improves short-term memory. They also pose a problem for short-term memory theories asserting that forgetting is based on domain-specific interference given that chewing does not interfere with verbal memory any more than tapping. It is suggested that tapping and chewing reduce the general capacity to process sequences.

What part of working memory is not working in ADHD? Short-term memory, the central executive and effects of reinforcement

NARCIS (Netherlands)

Dovis, S.; van der Oord, S.; Wiers, R.W.; Prins, P.J.M.

2013-01-01

Deficits in Working Memory (WM) are related to symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD). In children with ADHD visuospatial WM is most impaired. WM is composed of Short-Term Memory (STM) and a Central Executive (CE). Therefore, deficits in either or both STM and the CE may account

A severe capacity limit in the consolidation of orientation information into visual short-term memory.

Science.gov (United States)

Becker, Mark W; Miller, James R; Liu, Taosheng

2013-04-01

Previous research has suggested that two color patches can be consolidated into visual short-term memory (VSTM) via an unlimited parallel process. Here we examined whether the same unlimited-capacity parallel process occurs for two oriented grating patches. Participants viewed two gratings that were presented briefly and masked. In blocks of trials, the gratings were presented either simultaneously or sequentially. In Experiments 1 and 2, the presentation of the stimuli was followed by a location cue that indicated the grating on which to base one's response. In Experiment 1, participants responded whether the target grating was oriented clockwise or counterclockwise with respect to vertical. In Experiment 2, participants indicated whether the target grating was oriented along one of the cardinal directions (vertical or horizontal) or was obliquely oriented. Finally, in Experiment 3, the location cue was replaced with a third grating that appeared at fixation, and participants indicated whether either of the two test gratings matched this probe. Despite the fact that these responses required fairly coarse coding of the orientation information, across all methods of responding we found superior performance for sequential over simultaneous presentations. These findings suggest that the consolidation of oriented gratings into VSTM is severely limited in capacity and differs from the consolidation of color information.

Evaluation of Short Term Memory Span Function In Children

OpenAIRE

Barış ERGÜL; Arzu ALTIN YAVUZ; Ebru GÜNDOĞAN AŞIK

2016-01-01

Although details of the information encoded in the short-term memory where it is stored temporarily be recorded in the working memory in the next stage. Repeating the information mentally makes it remain in memory for a long time. Studies investigating the relationship between short-term memory and reading skills that are carried out to examine the relationship between short-term memory processes and reading comprehension. In this study information coming to short-term memory and the factors ...

The scope and control of attention: Sources of variance in working memory capacity.

Science.gov (United States)

Chow, Michael; Conway, Andrew R A

2015-04-01

Working memory capacity is a strong positive predictor of many cognitive abilities, across various domains. The pattern of positive correlations across domains has been interpreted as evidence for a unitary source of inter-individual differences in behavior. However, recent work suggests that there are multiple sources of variance contributing to working memory capacity. The current study (N = 71) investigates individual differences in the scope and control of attention, in addition to the number and resolution of items maintained in working memory. Latent variable analyses indicate that the scope and control of attention reflect independent sources of variance and each account for unique variance in general intelligence. Also, estimates of the number of items maintained in working memory are consistent across tasks and related to general intelligence whereas estimates of resolution are task-dependent and not predictive of intelligence. These results provide insight into the structure of working memory, as well as intelligence, and raise new questions about the distinction between number and resolution in visual short-term memory.

Insensitivity of visual short-term memory to irrelevant visual information.

Science.gov (United States)

Andrade, Jackie; Kemps, Eva; Werniers, Yves; May, Jon; Szmalec, Arnaud

2002-07-01

Several authors have hypothesized that visuo-spatial working memory is functionally analogous to verbal working memory. Irrelevant background speech impairs verbal short-term memory. We investigated whether irrelevant visual information has an analogous effect on visual short-term memory, using a dynamic visual noise (DVN) technique known to disrupt visual imagery (Quinn & McConnell, 1996b). Experiment I replicated the effect of DVN on pegword imagery. Experiments 2 and 3 showed no effect of DVN on recall of static matrix patterns, despite a significant effect of a concurrent spatial tapping task. Experiment 4 showed no effect of DVN on encoding or maintenance of arrays of matrix patterns, despite testing memory by a recognition procedure to encourage visual rather than spatial processing. Serial position curves showed a one-item recency effect typical of visual short-term memory. Experiment 5 showed no effect of DVN on short-term recognition of Chinese characters, despite effects of visual similarity and a concurrent colour memory task that confirmed visual processing of the characters. We conclude that irrelevant visual noise does not impair visual short-term memory. Visual working memory may not be functionally analogous to verbal working memory, and different cognitive processes may underlie visual short-term memory and visual imagery.

A short-term neural network memory

Energy Technology Data Exchange (ETDEWEB)

Morris, R.J.T.; Wong, W.S.

1988-12-01

Neural network memories with storage prescriptions based on Hebb's rule are known to collapse as more words are stored. By requiring that the most recently stored word be remembered precisely, a new simple short-term neutral network memory is obtained and its steady state capacity analyzed and simulated. Comparisons are drawn with Hopfield's method, the delta method of Widrow and Hoff, and the revised marginalist model of Mezard, Nadal, and Toulouse.

The role of inhibition for working memory processes: ERP evidence from a short-term storage task.

Science.gov (United States)

Getzmann, Stephan; Wascher, Edmund; Schneider, Daniel

2018-05-01

Human working memory is the central unit for short-term storage of information. In addition to the selection and adequate storage of relevant information, the suppression of irrelevant stimuli from the environment seems to be of importance for working memory processes. To learn more about the interplay of information uptake and inhibition of irrelevant information, the present study used ERP measures and a short-term storage and retrieval task, in which pairs of either numbers or letters had to be compared. Random sequences of four stimuli (two numbers and two letters) were presented, with either the numbers or the letters being relevant for comparison. The analysis of ERPs to each of the four stimuli indicated more pronounced P2 and P3b amplitudes for relevant than irrelevant stimuli. In contrast, the N2 (reflecting inhibitory control) was only elicited by irrelevant stimuli. Moreover, the N2 amplitude of the second irrelevant stimulus was associated with behavioral performance, indicating the importance of inhibition of task-irrelevant stimuli for working memory processes. In sum, the findings demonstrate the role of cognitive control mechanisms for protecting relevant contents in working memory against irrelevant information. © 2017 Society for Psychophysiological Research.

Working Memory Capacity and Its Relation to Stroop Interference and Facilitation Effects in Individuals with Mild Cognitive Impairment

Science.gov (United States)

Sung, Jee Eun; Kim, Jin Hee; Jeong, Jee Hyang; Kang, Heejin

2012-01-01

Purpose: The purposes of the study were to investigate (a) the task-specific differences in short-term memory (STM) and working memory capacity (WMC) in individuals with mild cognitive impairment (MCI) and normal elderly adults (NEAs), (b) the Stroop interference and facilitation effects, and (c) the relationship of STM and WMC to the Stroop…

Interactions between Attention and Visual Short-Term Memory (VSTM): What Can Be Learnt from Individual and Developmental Differences?

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Astle, Duncan E.; Scerif, Gaia

2011-01-01

An ever increasing amount of research in the fields of developmental psychology and adult cognitive neuroscience explores attentional control as a driver of visual short-term and working memory capacity limits ("VSTM" and "VWM", respectively). However, these literatures have thus far been disparate: they use different measures or different labels,…

Short- and long-term memory contributions to immediate serial recognition: evidence from serial position effects.

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Purser, Harry; Jarrold, Christopher

2010-04-01

A long-standing body of research supports the existence of separable short- and long-term memory systems, relying on phonological and semantic codes, respectively. The aim of the current study was to measure the contribution of long-term knowledge to short-term memory performance by looking for evidence of phonologically and semantically coded storage within a short-term recognition task, among developmental samples. Each experimental trial presented 4-item lists. In Experiment 1 typically developing children aged 5 to 6 years old showed evidence of phonologically coded storage across all 4 serial positions, but evidence of semantically coded storage at Serial Positions 1 and 2. In a further experiment, a group of individuals with Down syndrome was investigated as a test case that might be expected to use semantic coding to support short-term storage, but these participants showed no evidence of semantically coded storage and evidenced phonologically coded storage only at Serial Position 4, suggesting that individuals with Down syndrome have a verbal short-term memory capacity of 1 item. Our results suggest that previous evidence of semantic effects on "short-term memory performance" does not reflect semantic coding in short-term memory itself, and provide an experimental method for researchers wishing to take a relatively pure measure of verbal short-term memory capacity, in cases where rehearsal is unlikely.

Making short-term international medical volunteer placements work: a qualitative study.

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Elnawawy, Omnia; Lee, Andrew C K; Pohl, Gerda

2014-06-01

International medical volunteering has grown in recent decades. It has the potential to benefit and harm the volunteer and host countries; but there is a paucity of literature on the impacts of international medical volunteering and a need to find ways to optimise the benefits of such placements. In this study, one example of international medical volunteering was examined involving British GPs on short-term placements in Nepal. The intention was to explore the expectations and experiences of the local health workers, volunteers, and host organisation to try and understand what makes volunteer placements work. Qualitative study of key informant interviews. Stakeholders of a short-term international medical volunteer (IMV) placement programme in Nepal. Key informant interviews were carried out via face-to-face or telephone/internet interviews with five previous volunteers, three representatives from a non-governmental organisation providing placements, and five local health workers in Nepal who had had contact with the IMVs. Interviews were recorded, transcribed, and analysed using standard thematic framework approaches. All the stakeholders had their own specific motives for participating in the IMV programme. The relationship between volunteers and the Nepalese health workers was complex and characterised by discrepant and occasionally unrealistic expectations. Managing these different expectations was challenging. Contextual issues and cultural differences are important considerations in medical volunteer programmes, and this study highlights the importance of robust preparation pre-placement for the volunteer and host to ensure positive outcomes. © British Journal of General Practice 2014.

Neural Correlates of Visual Short-term Memory Dissociate between Fragile and Working Memory Representations.

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Vandenbroucke, Annelinde R E; Sligte, Ilja G; de Vries, Jade G; Cohen, Michael X; Lamme, Victor A F

2015-12-01

Evidence is accumulating that the classic two-stage model of visual STM (VSTM), comprising iconic memory (IM) and visual working memory (WM), is incomplete. A third memory stage, termed fragile VSTM (FM), seems to exist in between IM and WM [Vandenbroucke, A. R. E., Sligte, I. G., & Lamme, V. A. F. Manipulations of attention dissociate fragile visual STM from visual working memory. Neuropsychologia, 49, 1559-1568, 2011; Sligte, I. G., Scholte, H. S., & Lamme, V. A. F. Are there multiple visual STM stores? PLoS One, 3, e1699, 2008]. Although FM can be distinguished from IM using behavioral and fMRI methods, the question remains whether FM is a weak expression of WM or a separate form of memory with its own neural signature. Here, we tested whether FM and WM in humans are supported by dissociable time-frequency features of EEG recordings. Participants performed a partial-report change detection task, from which individual differences in FM and WM capacity were estimated. These individual FM and WM capacities were correlated with time-frequency characteristics of the EEG signal before and during encoding and maintenance of the memory display. FM capacity showed negative alpha correlations over peri-occipital electrodes, whereas WM capacity was positively related, suggesting increased visual processing (lower alpha) to be related to FM capacity. Furthermore, FM capacity correlated with an increase in theta power over central electrodes during preparation and processing of the memory display, whereas WM did not. In addition to a difference in visual processing characteristics, a positive relation between gamma power and FM capacity was observed during both preparation and maintenance periods of the task. On the other hand, we observed that theta-gamma coupling was negatively correlated with FM capacity, whereas it was slightly positively correlated with WM. These data show clear differences in the neural substrates of FM versus WM and suggest that FM depends more on

Short-term synaptic plasticity and heterogeneity in neural systems

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Mejias, J. F.; Kappen, H. J.; Longtin, A.; Torres, J. J.

2013-01-01

We review some recent results on neural dynamics and information processing which arise when considering several biophysical factors of interest, in particular, short-term synaptic plasticity and neural heterogeneity. The inclusion of short-term synaptic plasticity leads to enhanced long-term memory capacities, a higher robustness of memory to noise, and irregularity in the duration of the so-called up cortical states. On the other hand, considering some level of neural heterogeneity in neuron models allows neural systems to optimize information transmission in rate coding and temporal coding, two strategies commonly used by neurons to codify information in many brain areas. In all these studies, analytical approximations can be made to explain the underlying dynamics of these neural systems.

Attentional Demands Predict Short-Term Memory Load Response in Posterior Parietal Cortex

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Magen, Hagit; Emmanouil, Tatiana-Aloi; McMains, Stephanie A.; Kastner, Sabine; Treisman, Anne

2009-01-01

Limits to the capacity of visual short-term memory (VSTM) indicate a maximum storage of only 3 or 4 items. Recently, it has been suggested that activity in a specific part of the brain, the posterior parietal cortex (PPC), is correlated with behavioral estimates of VSTM capacity and might reflect a capacity-limited store. In three experiments that…

Verbal Short-Term Memory Span in Children: Long-Term Modality Dependent Effects of Intrauterine Growth Restriction

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Geva, R.; Eshel, R.; Leitner, Y.; Fattal-Valevski, A.; Harel, S.

2008-01-01

Background: Recent reports showed that children born with intrauterine growth restriction (IUGR) are at greater risk of experiencing verbal short-term memory span (STM) deficits that may impede their learning capacities at school. It is still unknown whether these deficits are modality dependent. Methods: This long-term, prospective design study…

Strengthened effective connectivity underlies transfer of working memory training to tests of short-term memory and attention.

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Kundu, Bornali; Sutterer, David W; Emrich, Stephen M; Postle, Bradley R

2013-05-15

Although long considered a natively endowed and fixed trait, working memory (WM) ability has recently been shown to improve with intensive training. What remains controversial and poorly understood, however, are the neural bases of these training effects and the extent to which WM training gains transfer to other cognitive tasks. Here we present evidence from human electrophysiology (EEG) and simultaneous transcranial magnetic stimulation and EEG that the transfer of WM training to other cognitive tasks is supported by changes in task-related effective connectivity in frontoparietal and parieto-occipital networks that are engaged by both the trained and transfer tasks. One consequence of this effect is greater efficiency of stimulus processing, as evidenced by changes in EEG indices of individual differences in short-term memory capacity and in visual search performance. Transfer to search-related activity provides evidence that something more fundamental than task-specific strategy or stimulus-specific representations has been learned. Furthermore, these patterns of training and transfer highlight the role of common neural systems in determining individual differences in aspects of visuospatial cognition.

The temporal evolution of electromagnetic markers sensitive to the capacity limits of visual short-term memory.

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Mitchell, Daniel J; Cusack, Rhodri

2011-01-01

An electroencephalographic (EEG) marker of the limited contents of human visual short-term memory (VSTM) has previously been described. Termed contralateral delay activity, this consists of a sustained, posterior, negative potential that correlates with memory load and is greatest contralateral to the remembered hemifield. The current investigation replicates this finding and uses magnetoencephalography (MEG) to characterize its magnetic counterparts and their neural generators as they evolve throughout the memory delay. A parametric manipulation of memory load, within and beyond capacity limits, allows separation of signals that asymptote with behavioral VSTM performance from additional responses that contribute to a linear increase with set-size. Both EEG and MEG yielded bilateral signals that track the number of objects held in memory, and contralateral signals that are independent of memory load. In MEG, unlike EEG, the contralateral interaction between hemisphere and item load is much weaker, suggesting that bilateral and contralateral markers of memory load reflect distinct sources to which EEG and MEG are differentially sensitive. Nonetheless, source estimation allowed both the bilateral and the weaker contralateral capacity-limited responses to be localized, along with a load-independent contralateral signal. Sources of global and hemisphere-specific signals all localized to the posterior intraparietal sulcus during the early delay. However the bilateral load response peaked earlier and its generators shifted later in the delay. Therefore the hemifield-specific response may be more closely tied to memory maintenance while the global load response may be involved in initial processing of a limited number of attended objects, such as their individuation or consolidation into memory.

The temporal evolution of electromagnetic markers sensitive to the capacity limits of visual short-term memory

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Daniel James Mitchell

2011-02-01

Full Text Available An electroencephalographic (EEG marker of the limited contents of human visual short-term memory (VSTM has previously been described. Termed contralateral delay activity (CDA, this consists of a sustained, posterior, negative potential that correlates with memory load and is greatest contralateral to the remembered hemifield. The current investigation replicates this finding and uses magnetoencephalography (MEG to characterise its magnetic counterparts and their neural generators as they evolve throughout the memory delay. A parametric manipulation of memory load, within and beyond capacity limits, allows separation of signals that asymptote with behavioural VSTM performance from additional responses that contribute to a linear increase with set-size. Both EEG and MEG yielded bilateral signals that track the number of objects held in memory, and contralateral signals that are independent of memory load. In MEG, unlike EEG, the contralateral interaction between hemisphere and item load is much weaker, suggesting that bilateral and contralateral markers of memory load reflect distinct sources to which EEG and MEG are differentially sensitive. Nonetheless, source estimation allowed both the bilateral and the weaker contralateral capacity-limited responses to be localised, along with a load-independent contralateral signal. Sources of global and hemisphere-specific signals all localised to the posterior intraparietal sulcus during the early delay. However the bilateral load response peaked earlier and its generators shifted later in the delay. Therefore the hemifield-specific response may be more closely tied to memory maintenance while the global load response may be involved in initial processing of a limited number of attended objects, such as their individuation or consolidation into memory.

A direct comparison of short-term audiomotor and visuomotor memory.

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Ward, Amanda M; Loucks, Torrey M; Ofori, Edward; Sosnoff, Jacob J

2014-04-01

Audiomotor and visuomotor short-term memory are required for an important variety of skilled movements but have not been compared in a direct manner previously. Audiomotor memory capacity might be greater to accommodate auditory goals that are less directly related to movement outcome than for visually guided tasks. Subjects produced continuous isometric force with the right index finger under auditory and visual feedback. During the first 10 s of each trial, subjects received continuous auditory or visual feedback. For the following 15 s, feedback was removed but the force had to be maintained accurately. An internal effort condition was included to test memory capacity in the same manner but without external feedback. Similar decay times of ~5-6 s were found for vision and audition but the decay time for internal effort was ~4 s. External feedback thus provides an advantage in maintaining a force level after feedback removal, but may not exclude some contribution from a sense of effort. Short-term memory capacity appears longer than certain previous reports but there may not be strong distinctions in capacity across different sensory modalities, at least for isometric force.

The Development of Visual Short-Term Memory for Multifeature Items during Middle childhood

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Riggs, Kevin J.; Simpson, Andrew; Potts, Thomas

2011-01-01

Visual short-term memory (VSTM) research suggests that the adult capacity is limited to three or four multifeature object representations. Despite evidence supporting a developmental increase in capacity, it remains unclear what the unit of capacity is in children. The current study employed the change detection paradigm to investigate both the…

Modeling the Effects of Trait Diversity on Short-term Adaptive Capacity and Long-term Productivity of Phytoplankton Communities

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Smith, S. L.; Vallina, S. M.; Merico, A.

2016-02-01

We examine Biodiversity and Ecosystem Function (BEF) in a model phytoplankton community, using two recently developed mechanisms for sustaining diversity. The Trait Diffusion (TD) formulation represents the maintenance of diversity via endogenous mechanisms, such as inter-generational trait plasticity and rapid evolution. The 'Kill-the-Winner' (KTW) formulation for grazing sustains prey biodiversity via the exogenous mechanism of active prey switching. We implement both TD and KTW in a continuous trait-distribution model using simplified size-scalings to define a gleaner-opportunist trade-off for a phytoplankton community. By simulating semi-continuous culture experiments with periodic external dilutions, we test the dynamic response of the phytoplankton community to different scenarios of pulsed nutrient supply. We quantify the short-term Adaptive Capacity (AC) of the community by the specific growth rate averaged over the first 3 days of perturbations, and the Long-term Productivity (LP) by its average over the entire 120 day period of perturbations. When either the frequency or intensity of pulses is low, both AC and LP tend to decrease with diversity (and vice versa). Trait diversity has more impact on AC, particularly for pulses of high frequency or intensity, for which it tends to increase gradually at first, then steeply, and then to saturate with increasing diversity. For pulses of moderate intensity and frequency, increasing trait diversity from low to moderate levels leads to a trade-off between enhancing AC while slightly decreasing LP. Ultimately, we find that sustaining diversity increases the speed at which the phytoplankton community changes its composition in terms of size and hence nutrient acquisition traits, which may have implications for the transfer of productivity through the foodweb.

Short-term and long-term deflection of reinforced hollow core ...

African Journals Online (AJOL)

This paper presents a study on different methods of analysis that are currently used by design codes to predict the short-term and long-term deflection of reinforced concrete slab systems and compares the predicted deflections with measured deflections. The experimental work to measure deflections involved the testing of ...

Visual short-term memory for sequential arrays.

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Kumar, Arjun; Jiang, Yuhong

2005-04-01

The capacity of visual short-term memory (VSTM) for a single visual display has been investigated in past research, but VSTM for multiple sequential arrays has been explored only recently. In this study, we investigate the capacity of VSTM across two sequential arrays separated by a variable stimulus onset asynchrony (SOA). VSTM for spatial locations (Experiment 1), colors (Experiments 2-4), orientations (Experiments 3 and 4), and conjunction of color and orientation (Experiment 4) were tested, with the SOA across the two sequential arrays varying from 100 to 1,500 msec. We find that VSTM for the trailing array is much better than VSTM for the leading array, but when averaged across the two arrays VSTM has a constant capacity independent of the SOA. We suggest that multiple displays compete for retention in VSTM and that separating information into two temporally discrete groups does not enhance the overall capacity of VSTM.

Assessment and Treatment of Short-Term and Working Memory Impairments in Stroke Aphasia: A Practical Tutorial

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Salis, Christos; Kelly, Helen; Code, Chris

2015-01-01

Background: Aphasia following stroke refers to impairments that affect the comprehension and expression of spoken and/or written language, and co-occurring cognitive deficits are common. In this paper we focus on short-term and working memory impairments that impact on the ability to retain and manipulate auditory-verbal information. Evidence from…

Optimization of Highway Work Zone Decisions Considering Short-Term and Long-Term Impacts

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2010-01-01

year when rehabilitation is conducted c0 vph Maximum discharge rate without work zone cw vph Maximum discharge rate with work zone CT $/project...vehicle class Q(t) vph Time-varying traffic flow volume Qp,max vph Maximum allowed diverted volume q(t) veh Time-varying number of vehicles in queue...and road capacity=1600 vph . Unlike single-regime Greenshield’s model, the traffic flow model converted from CORSIM car-following logic is multi

On some verbal short-term and working memory properties in patients suffering from clinical depression

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Lalović Dejan

2012-01-01

Full Text Available Clinical depression with verbal short-term memory relation research does not yield unequivocal results. While short-term memory (STM deficits in depressed patients are consistently displayed in working memory (WM and executive attention tasks, for STM passive memorizing tasks this holds less correct. Objective. Primary goal was to collect initial data on depressed patients treated in Serbian institutions WM/ STM. In addition, we estimated the power of WAIS IV WM subtests to discriminate depressed patients from normal subjects. Method. Depressed patients' sample was contrasted with the parallel group in WAIS' IV Arithmetic, Digit Span, and Letter- Number Sequencing; free word recall task, semantic fluency task, without and with category switching. Results. All the WM measures, with the exception of Digit Span Backward score, discriminate depressed from no depressed subjects. On the other hand, STM tasks, with the exception of short-term word free recall, fail to do the same. We suggest explanation for both the exceptions in terms of WM efficiency. WAIS IV Arithmetic, Digit Span Sequencing and Letter-Number Sequencing can be used to discriminate depressed from control subjects. Performance in STM/WM tasks is in moderate to strong negative correlation with depression severity as assessed with the Hamilton scale. Conclusion. STM deficits in the depressed are likely to be observed in tasks requiring executive attention and WM efficiency rather than in standard STM span tasks. The deficits are inertly related to depression severity.

Do Short-Term Managerial Objectives Lead to Under- or Over-Investment in Long-Term Projects

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Lucian Arye Bebchuk; Lars A. Stole

1994-01-01

This paper studies managerial decisions about investment in long-run projects in the presence of imperfect information (the market knows less about such investments than the firm's managers) and short-term managerial objectives (the managers are concerned about the short-term stock price as well as the long-term stock price). Prior work has suggested that imperfect information and short-term managerial objectives induce managers to underinvest in long-run projects. We show that either underin...

L2 Working Memory Capacity and L2 Reading Skill.

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Harrington, Mike; Sawyer, Mark

1992-01-01

Examines the sensitivity of second-language (L2) working memory (ability to store and process information simultaneously) to differences in reading skills among advanced L2 learners. Subjects with larger L2 working memory capacities scored higher on measures of L2 reading skills, but no correlation was found between reading and passive short-term…

Audit of long-term and short-term liabilities

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Korinko M.D.

2017-03-01

Full Text Available The article determines the importance of long-term and short-term liabilities for the management of financial and material resources of an enterprise. It reviews the aim, objects and information generators for realization of audit of short-term and long-term obligations. The organizing and methodical providing of audit of long-term and short-term liabilities of an enterprise are generalized. The authors distinguish the stages of realization of audit of long-term and short-term liabilities, the aim of audit on each of the presented stages, and recommend methodical techniques. It is fixed that it is necessary to conduct the estimation of the systems of internal control and record-keeping of an enterprise by implementation of public accountant procedures for determination of volume and maintenance of selection realization. After estimating the indicated systems, a public accountant determines the methodology for realization of public accountant verification of long-term and short-term liabilities. The analytical procedures that public accountants are expedient to use for realization of audit of short-term and long-term obligations are determined. The authors suggest the classification of the educed defects on the results of the conducted public accountant verification of short-term and long-term obligations.

Visual Working Memory Capacity for Emotional Facial Expressions

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Domagoj Švegar

2011-12-01

Full Text Available The capacity of visual working memory is limited to no more than four items. At the same time, it is limited not only by the number of objects, but also by the total amount of information that needs to be memorized, and the relation between the information load per object and the number of objects that can be stored into visual working memory is inverse. The objective of the present experiment was to compute visual working memory capacity for emotional facial expressions, and in order to do so, change detection tasks were applied. Pictures of human emotional facial expressions were presented to 24 participants in 1008 experimental trials, each of which began with a presentation of a fixation mark, which was followed by a short simultaneous presentation of six emotional facial expressions. After that, a blank screen was presented, and after such inter-stimulus interval, one facial expression was presented at one of previously occupied locations. Participants had to answer if the facial expression presented at test is different or identical as the expression presented at that same location before the retention interval. Memory capacity was estimated through accuracy of responding, by the formula constructed by Pashler (1988, adopted from signal detection theory. It was found that visual working memory capacity for emotional facial expressions equals 3.07, which is high compared to capacity for facial identities and other visual stimuli. The obtained results were explained within the framework of evolutionary psychology.

Retrospective attention in short-term memory has a lasting effect on long-term memory across age.

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Strunk, Jonathan; Morgan, Lauren; Reaves, Sarah; Verhaeghen, Paul; Duarte, Audrey

2018-04-13

Declines in both short- and long-term memory are typical of healthy aging. Recent findings suggest that retrodictive attentional cues ("retro-cues") that indicate the location of to-be-probed items in short-term memory (STM) have a lasting impact on long-term memory (LTM) performance in young adults. Whether older adults can also use retro-cues to facilitate both STM and LTM is unknown. Young and older adults performed a visual STM task in which spatially informative retro-cues or non-informative neutral-cues were presented during STM maintenance of real-world objects. We tested participants' memory at both STM and LTM delays for objects that were previously cued with retrodictive or neutral cues during STM order to measure the lasting impact of retrospective attention on LTM. Older adults showed reduced STM and LTM capacity compared to young adults. However, they showed similar magnitude retro-cue memory benefits as young adults at both STM and LTM delays. To the best of our knowledge, this is the first study to investigate whether retro-cues in STM facilitate the encoding of objects into LTM such that they are more likely to be subsequently retrieved by older adults. Our results support the idea that retrospective attention can be an effective means by which older adults can improve their short and long-term memory performance, even in the context of reduced memory capacity.

Vocabulary learning in primary school children: working memory and long-term memory components.

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Morra, Sergio; Camba, Roberta

2009-10-01

The goal of this study was to investigate which working memory and long-term memory components predict vocabulary learning. We used a nonword learning paradigm in which 8- to 10-year-olds learned picture-nonword pairs. The nonwords varied in length (two vs. four syllables) and phonology (native sounding vs. including one Russian phoneme). Short, phonologically native nonwords were learned best, whereas learning long nonwords leveled off after a few presentation cycles. Linear structural equation analyses showed an influence of three constructs-phonological sensitivity, vocabulary knowledge, and central attentional resources (M capacity)-on nonword learning, but the extent of their contributions depended on specific characteristics of the nonwords to be learned. Phonological sensitivity predicted learning of all nonword types except short native nonwords, vocabulary predicted learning of only short native nonwords, and M capacity predicted learning of short nonwords but not long nonwords. The discussion considers three learning processes-effortful activation of phonological representations, lexical mediation, and passive associative learning-that use different cognitive resources and could be involved in learning different nonword types.

Working memory is not fixed-capacity: More active storage capacity for real-world objects than for simple stimuli.

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Brady, Timothy F; Störmer, Viola S; Alvarez, George A

2016-07-05

Visual working memory is the cognitive system that holds visual information active to make it resistant to interference from new perceptual input. Information about simple stimuli-colors and orientations-is encoded into working memory rapidly: In under 100 ms, working memory ‟fills up," revealing a stark capacity limit. However, for real-world objects, the same behavioral limits do not hold: With increasing encoding time, people store more real-world objects and do so with more detail. This boost in performance for real-world objects is generally assumed to reflect the use of a separate episodic long-term memory system, rather than working memory. Here we show that this behavioral increase in capacity with real-world objects is not solely due to the use of separate episodic long-term memory systems. In particular, we show that this increase is a result of active storage in working memory, as shown by directly measuring neural activity during the delay period of a working memory task using EEG. These data challenge fixed-capacity working memory models and demonstrate that working memory and its capacity limitations are dependent upon our existing knowledge.

Holding multiple items in short term memory: a neural mechanism.

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Edmund T Rolls

Full Text Available Human short term memory has a capacity of several items maintained simultaneously. We show how the number of short term memory representations that an attractor network modeling a cortical local network can simultaneously maintain active is increased by using synaptic facilitation of the type found in the prefrontal cortex. We have been able to maintain 9 short term memories active simultaneously in integrate-and-fire simulations where the proportion of neurons in each population, the sparseness, is 0.1, and have confirmed the stability of such a system with mean field analyses. Without synaptic facilitation the system can maintain many fewer memories active in the same network. The system operates because of the effectively increased synaptic strengths formed by the synaptic facilitation just for those pools to which the cue is applied, and then maintenance of this synaptic facilitation in just those pools when the cue is removed by the continuing neuronal firing in those pools. The findings have implications for understanding how several items can be maintained simultaneously in short term memory, how this may be relevant to the implementation of language in the brain, and suggest new approaches to understanding and treating the decline in short term memory that can occur with normal aging.

Holding multiple items in short term memory: a neural mechanism.

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Rolls, Edmund T; Dempere-Marco, Laura; Deco, Gustavo

2013-01-01

Human short term memory has a capacity of several items maintained simultaneously. We show how the number of short term memory representations that an attractor network modeling a cortical local network can simultaneously maintain active is increased by using synaptic facilitation of the type found in the prefrontal cortex. We have been able to maintain 9 short term memories active simultaneously in integrate-and-fire simulations where the proportion of neurons in each population, the sparseness, is 0.1, and have confirmed the stability of such a system with mean field analyses. Without synaptic facilitation the system can maintain many fewer memories active in the same network. The system operates because of the effectively increased synaptic strengths formed by the synaptic facilitation just for those pools to which the cue is applied, and then maintenance of this synaptic facilitation in just those pools when the cue is removed by the continuing neuronal firing in those pools. The findings have implications for understanding how several items can be maintained simultaneously in short term memory, how this may be relevant to the implementation of language in the brain, and suggest new approaches to understanding and treating the decline in short term memory that can occur with normal aging.

Holding Multiple Items in Short Term Memory: A Neural Mechanism

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Rolls, Edmund T.; Dempere-Marco, Laura; Deco, Gustavo

2013-01-01

Human short term memory has a capacity of several items maintained simultaneously. We show how the number of short term memory representations that an attractor network modeling a cortical local network can simultaneously maintain active is increased by using synaptic facilitation of the type found in the prefrontal cortex. We have been able to maintain 9 short term memories active simultaneously in integrate-and-fire simulations where the proportion of neurons in each population, the sparseness, is 0.1, and have confirmed the stability of such a system with mean field analyses. Without synaptic facilitation the system can maintain many fewer memories active in the same network. The system operates because of the effectively increased synaptic strengths formed by the synaptic facilitation just for those pools to which the cue is applied, and then maintenance of this synaptic facilitation in just those pools when the cue is removed by the continuing neuronal firing in those pools. The findings have implications for understanding how several items can be maintained simultaneously in short term memory, how this may be relevant to the implementation of language in the brain, and suggest new approaches to understanding and treating the decline in short term memory that can occur with normal aging. PMID:23613789

The Roles of Phonological Short-Term Memory and Working Memory in L2 Grammar and Vocabulary Learning

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Martin, Katherine I.; Ellis, Nick C.

2012-01-01

This study analyzed phonological short-term memory (PSTM) and working memory (WM) and their relationship with vocabulary and grammar learning in an artificial foreign language. Nonword repetition, nonword recognition, and listening span were used as memory measures. Participants learned the singular forms of vocabulary for an artificial foreign…

Conceptual Short Term Memory in perception and thought

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Mary C. Potter

2012-04-01

Full Text Available Conceptual short term memory (CSTM is a theoretical construct that provides one answer to the question of how perceptual and conceptual processes are related. CSTM is a mental buffer and processor in which current perceptual stimuli and their associated concepts from long term memory (LTM are represented briefly, allowing meaningful patterns or structures to be identified (Potter, 1993, 1999, 2009. CSTM is different from and complementary to other proposed forms of working memory: it is engaged extremely rapidly, has a large but ill-defined capacity, is largely unconscious, and is the basis for the unreflective understanding that is characteristic of everyday experience. The key idea behind CSTM is that most cognitive processing occurs without review or rehearsal of material in standard working memory and with little or no conscious reasoning. When one perceives a meaningful stimulus such as a word, picture, or object, it is rapidly identified at a conceptual level and in turn activates associated information from long term memory. New links among concurrently active concepts are formed in CSTM, shaped by parsing mechanisms of language or grouping principles in scene perception and by higher-level knowledge and current goals. The resulting structure represents the gist of a picture or the meaning of a sentence, and it is this structure that we are conscious of and that can be maintained in standard working memory and consolidated into long term memory. Momentarily activated information that is not incorporated into such structures either never becomes conscious or is rapidly forgotten. This whole cycle--identification of perceptual stimuli, memory recruitment, structuring, consolidation in long term memory, and forgetting of nonstructured material--may occur in less than 1 second when viewing a pictured scene or reading a sentence. The evidence for such a process is reviewed and its implications for the relation of perception and cognition are

Neuroticism and conscientiousness respectively constrain and facilitate short-term plasticity within the working memory neural network.

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Dima, Danai; Friston, Karl J; Stephan, Klaas E; Frangou, Sophia

2015-10-01

Individual differences in cognitive efficiency, particularly in relation to working memory (WM), have been associated both with personality dimensions that reflect enduring regularities in brain configuration, and with short-term neural plasticity, that reflects task-related changes in brain connectivity. To elucidate the relationship of these two divergent mechanisms, we tested the hypothesis that personality dimensions, which reflect enduring aspects of brain configuration, inform about the neurobiological framework within which short-term, task-related plasticity, as measured by effective connectivity, can be facilitated or constrained. As WM consistently engages the dorsolateral prefrontal (DLPFC), parietal (PAR), and anterior cingulate cortex (ACC), we specified a WM network model with bidirectional, ipsilateral, and contralateral connections between these regions from a functional magnetic resonance imaging dataset obtained from 40 healthy adults while performing the 3-back WM task. Task-related effective connectivity changes within this network were estimated using Dynamic Causal Modelling. Personality was evaluated along the major dimensions of Neuroticism, Extraversion, Openness to Experience, Agreeableness, and Conscientiousness. Only two dimensions were relevant to task-dependent effective connectivity. Neuroticism and Conscientiousness respectively constrained and facilitated neuroplastic responses within the WM network. These results suggest individual differences in cognitive efficiency arise from the interplay between enduring and short-term plasticity in brain configuration. © 2015 Wiley Periodicals, Inc.

Evaluation of Short Term Memory Span Function In Children

Directory of Open Access Journals (Sweden)

Barış ERGÜL

2016-12-01

Full Text Available Although details of the information encoded in the short-term memory where it is stored temporarily be recorded in the working memory in the next stage. Repeating the information mentally makes it remain in memory for a long time. Studies investigating the relationship between short-term memory and reading skills that are carried out to examine the relationship between short-term memory processes and reading comprehension. In this study information coming to short-term memory and the factors affecting operation of short term memory are investigated with regression model. The aim of the research is to examine the factors (age, IQ and reading skills that are expected the have an effect on short-term memory in children through regression analysis. One of the assumptions of regression analysis is to examine which has constant variance and normal distribution of the error term. In this study, because the error term is not normally distributed, robust regression techniques were applied. Also, for each technique; coefficient of determination is determined. According to the findings, the increase in age, IQ and reading skills caused the increase in short term memory in children. After applying robust regression techniques, the Winsorized Least Squares (WLS technique gives the highest coefficient of determination.

Short-term robustness of production management systems

NARCIS (Netherlands)

Kleijnen, J.P.C.; Gaury, E.G.A.

1998-01-01

Short-term performance of a production management system for make-to-stock factories may be quantified through the service rate per shift; long-term performance through the average monthly work in process (WIP). This may yield, for example, that WIP is minimized, while the probability of the service

Short-term effects of night shift work on breast cancer risk: a cohort study of payroll data.

Science.gov (United States)

Vistisen, Helene Tilma; Garde, Anne Helene; Frydenberg, Morten; Christiansen, Peer; Hansen, Åse Marie; Andersen, Johnni; Bonde, Jens Peter E; Kolstad, Henrik A

2017-01-01

Objectives The objective was to examine if night shift work is a short-term risk factor for breast cancer, including combined estrogen receptor (ER) and human epidermal growth factor 2 (HER2) breast cancer subtypes. Methods The cohort comprised 155 540 public sector female workers in Denmark who were followed from 2007-2012. Day-to-day work-hour information was available from payroll registers and 1245 incident cases of breast cancer were identified in national cancer registries together with receptor subtype information. Results A rate ratio (RR) of 0.90 [95% confidence interval (95% CI) 0.80-1.01] was observed for workers ever working night shifts during the follow-up period compared with workers only working day shifts after adjustment for age, age at first child, parity, family history of breast or ovarian cancer, sex hormones, medications related to alcoholism, family educational level, mammography screening, and other potential confounders. Comparable results were seen for the inception population of employees with first recorded employment after 2007. Modestly increased RR were suggested for breast cancer subtypes characterized by a positive HER2 status irrespective of ER status. Conclusions These findings do not support an overall short-term effect of night shift work on breast cancer risk. Future studies should explore further the impact of HER2 status.

The Structure and Content of Long-Term and Short-Term Mate Preferences

Directory of Open Access Journals (Sweden)

Peter K. Jonason

2013-12-01

Full Text Available This study addresses two limitations in the mate preferences literature. First, research all-too-often relies on single-item assessments of mate preferences precluding more advanced statistical techniques like factor analysis. Second, when factor analysis could be done, it exclusively has done for long-term mate preferences, at the exclusion of short-term mate preferences. In this study (N = 401, we subjected 20 items designed to measure short- and long-term mate preferences to both principle components (n = 200 and confirmatory factor analysis (n = 201. In the long-term context, we replicated previous findings that there are three different categories of preferences: physical attractiveness, interpersonal warmth, and social status. In the short-term context, physical attractiveness occupied two parts of the structure, social status dropped out, and interpersonal warmth remained. Across short- and long-term contexts, there were slight changes in what defined the shared dimensions (i.e., physical attractiveness and interpersonal warmth, suggesting prior work that applies the same inventory to each context might be flawed. We also replicated sex differences and similarities in mate preferences and correlates with sociosexuality and mate value. We adopt an evolutionary paradigm to understand our results.

Strengthening health workforce capacity through work-based training

Directory of Open Access Journals (Sweden)

Matovu Joseph KB

2013-01-01

Full Text Available Abstract Background Although much attention has been given to increasing the number of health workers, less focus has been directed at developing models of training that address real-life workplace needs. Makerere University School of Public Health (MakSPH with funding support from the Centers for Disease Control and Prevention (CDC developed an eight-month modular, in-service work-based training program aimed at strengthening the capacity for monitoring and evaluation (M&E and continuous quality improvement (CQI in health service delivery. Methods This capacity building program, initiated in 2008, is offered to in-service health professionals working in Uganda. The purpose of the training is to strengthen the capacity to provide quality health services through hands-on training that allows for skills building with minimum work disruptions while encouraging greater involvement of other institutional staff to enhance continuity and sustainability. The hands-on training uses practical gaps and challenges at the workplace through a highly participatory process. Trainees work with other staff to design and implement ‘projects’ meant to address work-related priority problems, working closely with mentors. Trainees’ knowledge and skills are enhanced through short courses offered at specific intervals throughout the course. Results Overall, 143 trainees were admitted between 2008 and 2011. Of these, 120 (84% from 66 institutions completed the training successfully. Of the trainees, 37% were Social Scientists, 34% were Medical/Nursing/Clinical Officers, 5.8% were Statisticians, while 23% belonged to other professions. Majority of the trainees (80% were employed by Non-Government Organizations while 20% worked with the public health sector. Trainees implemented 66 projects which addressed issues such as improving access to health care services; reducing waiting time for patients; strengthening M&E systems; and improving data collection and

As the world turns: short-term human spatial memory in egocentric and allocentric coordinates.

Science.gov (United States)

Banta Lavenex, Pamela; Lecci, Sandro; Prêtre, Vincent; Brandner, Catherine; Mazza, Christian; Pasquier, Jérôme; Lavenex, Pierre

2011-05-16

We aimed to determine whether human subjects' reliance on different sources of spatial information encoded in different frames of reference (i.e., egocentric versus allocentric) affects their performance, decision time and memory capacity in a short-term spatial memory task performed in the real world. Subjects were asked to play the Memory game (a.k.a. the Concentration game) without an opponent, in four different conditions that controlled for the subjects' reliance on egocentric and/or allocentric frames of reference for the elaboration of a spatial representation of the image locations enabling maximal efficiency. We report experimental data from young adult men and women, and describe a mathematical model to estimate human short-term spatial memory capacity. We found that short-term spatial memory capacity was greatest when an egocentric spatial frame of reference enabled subjects to encode and remember the image locations. However, when egocentric information was not reliable, short-term spatial memory capacity was greater and decision time shorter when an allocentric representation of the image locations with respect to distant objects in the surrounding environment was available, as compared to when only a spatial representation encoding the relationships between the individual images, independent of the surrounding environment, was available. Our findings thus further demonstrate that changes in viewpoint produced by the movement of images placed in front of a stationary subject is not equivalent to the movement of the subject around stationary images. We discuss possible limitations of classical neuropsychological and virtual reality experiments of spatial memory, which typically restrict the sensory information normally available to human subjects in the real world. Copyright © 2011 Elsevier B.V. All rights reserved.

The Sensory Components of High-Capacity Iconic Memory and Visual Working Memory

OpenAIRE

Bradley, Claire; Pearson, Joel

2012-01-01

Early visual memory can be split into two primary components: a high-capacity, short-lived iconic memory followed by a limited-capacity visual working memory that can last many seconds. Whereas a large number of studies have investigated visual working memory for low-level sensory features, much research on iconic memory has used more “high-level” alphanumeric stimuli such as letters or numbers. These two forms of memory are typically examined separately, despite an intrinsic overlap in their...

The sensory components of high-capacity iconic memory and visual working memory

OpenAIRE

Claire eBradley; Claire eBradley; Joel ePearson

2012-01-01

Early visual memory can be split into two primary components: a high-capacity, short-lived iconic memory followed by a limited-capacity visual working memory that can last many seconds. Whereas a large number of studies have investigated visual working memory for low-level sensory features, much research on iconic memory has used more high-level alphanumeric stimuli such as letters or numbers. These two forms of memory are typically examined separately, despite an intrinsic overlap in their c...

A Visual Short-Term Memory Advantage for Objects of Expertise

Science.gov (United States)

Curby, Kim M.; Glazek, Kuba; Gauthier, Isabel

2009-01-01

Visual short-term memory (VSTM) is limited, especially for complex objects. Its capacity, however, is greater for faces than for other objects; this advantage may stem from the holistic nature of face processing. If the holistic processing explains this advantage, object expertise--which also relies on holistic processing--should endow experts…

The IEA Model of Short-term Energy Security

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-07-01

Ensuring energy security has been at the centre of the IEA mission since its inception, following the oil crises of the early 1970s. While the security of oil supplies remains important, contemporary energy security policies must address all energy sources and cover a comprehensive range of natural, economic and political risks that affect energy sources, infrastructures and services. In response to this challenge, the IEA is currently developing a Model Of Short-term Energy Security (MOSES) to evaluate the energy security risks and resilience capacities of its member countries. The current version of MOSES covers short-term security of supply for primary energy sources and secondary fuels among IEA countries. It also lays the foundation for analysis of vulnerabilities of electricity and end-use energy sectors. MOSES contains a novel approach to analysing energy security, which can be used to identify energy security priorities, as a starting point for national energy security assessments and to track the evolution of a country's energy security profile. By grouping together countries with similar 'energy security profiles', MOSES depicts the energy security landscape of IEA countries. By extending the MOSES methodology to electricity security and energy services in the future, the IEA aims to develop a comprehensive policy-relevant perspective on global energy security. This Working Paper is intended for readers who wish to explore the MOSES methodology in depth; there is also a brochure which provides an overview of the analysis and results.

V4 activity predicts the strength of visual short-term memory representations

NARCIS (Netherlands)

Sligte, I.G.; Scholte, H.S.; Lamme, V.A.F.

2009-01-01

Recent studies have shown the existence of a form of visual memory that lies intermediate of iconic memory and visual short-term memory (VSTM), in terms of both capacity (up to 15 items) and the duration of the memory trace (up to 4 s). Because new visual objects readily overwrite this intermediate

Insensitivity of visual short-term memory to irrelevant visual information

OpenAIRE

Andrade, Jackie; Kemps, Eva; Werniers, Yves; May, Jon; Szmalec, Arnaud

2002-01-01

Several authors have hypothesised that visuo-spatial working memory is functionally analogous to verbal working memory. Irrelevant background speech impairs verbal short-term memory. We investigated whether irrelevant visual information has an analogous effect on visual short-term memory, using a dynamic visual noise (DVN) technique known to disrupt visual imagery (Quinn & McConnell, 1996a). Experiment 1 replicated the effect of DVN on pegword imagery. Experiments 2 and 3 showed no effect of ...

Inhibition of connexin43 hemichannels impairs spatial short-term memory without affecting spatial working memory

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Laura Walrave

2016-12-01

Full Text Available Astrocytes are active players in higher brain function as they can release gliotransmitters, which are essential for synaptic plasticity. Various mechanisms have been proposed for gliotransmission, including vesicular mechanisms as well as non-vesicular ones, for example by passive diffusion via connexin hemichannels (HCs. We here investigated whether interfering with connexin43 (Cx43 HCs influenced hippocampal spatial memory. We made use of the peptide Gap19 that blocks HCs but not gap junction channels and is specific for Cx43. To this end, we microinfused transactivator of transcription linked Gap19 (TAT-Gap19 into the brain ventricle of male NMRI mice and assessed spatial memory in a Y maze. We found that the in vivo blockade of Cx43 HCs did not affect the locomotor activity or spatial working memory in a spontaneous alternation Y maze task. Cx43 blockade did however significantly impair the spatial short-term memory in a delayed spontaneous alternation Y maze task. These results indicate that Cx43 HCs play a role in spatial short-term memory.

Decay uncovered in nonverbal short-term memory.

Science.gov (United States)

Mercer, Tom; McKeown, Denis

2014-02-01

Decay theory posits that memory traces gradually fade away over the passage of time unless they are actively rehearsed. Much recent work exploring verbal short-term memory has challenged this theory, but there does appear to be evidence for trace decay in nonverbal auditory short-term memory. Numerous discrimination studies have reported a performance decline as the interval separating two tones is increased, consistent with a decay process. However, most of this tone comparison research can be explained in other ways, without reference to decay, and these alternative accounts were tested in the present study. In Experiment 1, signals were employed toward the end of extended retention intervals to ensure that listeners were alert to the presence and frequency content of the memoranda. In Experiment 2, a mask stimulus was employed in an attempt to distinguish between a highly detailed sensory trace and a longer-lasting short-term memory, and the distinctiveness of the stimuli was varied. Despite these precautions, slow-acting trace decay was observed. It therefore appears that the mere passage of time can lead to forgetting in some forms of short-term memory.

Impact of short-term severe accident management actions in a long-term perspective. Final Report

International Nuclear Information System (INIS)

2000-03-01

The present systems for severe accident management are focused on mitigating the consequences of special severe accident phenomena and to reach a safe plant state. However, in the development of strategies and procedures for severe accident management, it is also important to consider the long-term perspective of accident management and especially to secure the safe state of the plant. The main reason for this is that certain short-term actions have an impact on the long-term scenario. Both positive and negative effects from short-term actions on the accident management in the long-term perspective have been included in this paper. Short-term actions are accident management measures taken within about 24 hours after the initiating event. The purpose of short-term actions is to reach a stable status of the plant. The main goal in the long-term perspective is to maintain the reactor in a stable state and prevent uncontrolled releases of activity. The purpose of this short Technical Note, deliberately limited in scope, is to draw attention to potential long-term problems, important to utilities and regulatory authorities, arising from the way a severe accident would be managed during the first hours. Its objective is to encourage discussions on the safest - and maybe also most economical - way to manage a severe accident in the long term by not making the situation worse through inappropriate short-term actions, and on the identification of short-term actions likely to make long-term management easier and safer. The Note is intended as a contribution to the knowledge base put at the disposal of Member countries through international collaboration. The scope of the work has been limited to a literature search. Useful further activities have been identified. However, there is no proposal, at this stage, for more detailed work to be undertaken under the auspices of the CSNI. Plant-specific applications would need to be developed by utilities

The reliability and stability of visual working memory capacity.

Science.gov (United States)

Xu, Z; Adam, K C S; Fang, X; Vogel, E K

2018-04-01

Because of the central role of working memory capacity in cognition, many studies have used short measures of working memory capacity to examine its relationship to other domains. Here, we measured the reliability and stability of visual working memory capacity, measured using a single-probe change detection task. In Experiment 1, the participants (N = 135) completed a large number of trials of a change detection task (540 in total, 180 each of set sizes 4, 6, and 8). With large numbers of both trials and participants, reliability estimates were high (α > .9). We then used an iterative down-sampling procedure to create a look-up table for expected reliability in experiments with small sample sizes. In Experiment 2, the participants (N = 79) completed 31 sessions of single-probe change detection. The first 30 sessions took place over 30 consecutive days, and the last session took place 30 days later. This unprecedented number of sessions allowed us to examine the effects of practice on stability and internal reliability. Even after much practice, individual differences were stable over time (average between-session r = .76).

Errors in nonword repetition: bridging short- and long-term memory

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F.H. Santos

2006-03-01

Full Text Available According to the working memory model, the phonological loop is the component of working memory specialized in processing and manipulating limited amounts of speech-based information. The Children's Test of Nonword Repetition (CNRep is a suitable measure of phonological short-term memory for English-speaking children, which was validated by the Brazilian Children's Test of Pseudoword Repetition (BCPR as a Portuguese-language version. The objectives of the present study were: i to investigate developmental aspects of the phonological memory processing by error analysis in the nonword repetition task, and ii to examine phoneme (substitution, omission and addition and order (migration errors made in the BCPR by 180 normal Brazilian children of both sexes aged 4-10, from preschool to 4th grade. The dominant error was substitution [F(3,525 = 180.47; P < 0.0001]. The performance was age-related [F(4,175 = 14.53; P < 0.0001]. The length effect, i.e., more errors in long than in short items, was observed [F(3,519 = 108.36; P < 0.0001]. In 5-syllable pseudowords, errors occurred mainly in the middle of the stimuli, before the syllabic stress [F(4,16 = 6.03; P = 0.003]; substitutions appeared more at the end of the stimuli, after the stress [F(12,48 = 2.27; P = 0.02]. In conclusion, the BCPR error analysis supports the idea that phonological loop capacity is relatively constant during development, although school learning increases the efficiency of this system. Moreover, there are indications that long-term memory contributes to holding memory trace. The findings were discussed in terms of distinctiveness, clustering and redintegration hypotheses.

Stuttering interneurons generate fast and robust inhibition onto projection neurons with low capacity of short term modulation in mouse lateral amygdala.

Directory of Open Access Journals (Sweden)

Chen Song

Full Text Available The stuttering interneurons (STi represent one minor subset of interneuron population and exhibit characteristic stuttering firing upon depolarization current injection. While it has been long held that the GABAergic inhibitory transmission largely varies with the subtype identity of presynaptic interneurons, whether such a rule also applies to STi is largely unknown. Here, by paired recording of interneuron and their neighboring projection neuron in lateral amygdala, we found that relative to the fast spiking and late spiking interneurons, the STi-evoked unitary postsynaptic currents onto the projection neurons had markedly larger amplitude, shorter onset latency and faster rising and decay kinetics. The quantal content and the number of vesicles in the readily releasable pool were also larger in synapses made by STi versus other interneurons. Moreover, the short-term plasticity, as reflected by the paired pulse depression and depolarization-induced suppression of inhibition, was the least prominent in the output synapses of STi. Thus, the fast and robust inhibition together with its low capacity of short term modulation may suggest an important role for STi in preventing the overexcitation of the projection neurons and thus gating the information traffic in amygdala.

Verbal short-term memory in individuals with chromosome 22q11.2 deletion: specific deficit in serial order retention capacities?

Science.gov (United States)

Majerus, Steve; Van der Linden, Martial; Braissand, Vérane; Eliez, Stephan

2007-03-01

Many researchers have recently explored the cognitive profile of velocardiofacial syndrome (VCFS), a neurodevelopmental disorder linked to a 22q11.2 deletion. However, verbal short-term memory has not yet been systematically investigated. We explored verbal short-term memory abilities in a group of 11 children and adults presenting with VCFS and two control groups, matched on either CA or vocabulary knowledge, by distinguishing short-term memory for serial order and item information. The VCFS group showed impaired performance on the serial order short-term memory tasks compared to both control groups. Relative to the vocabulary-matched control group, item short-term memory was preserved. The implication of serial order short-term memory deficits on other aspects of cognitive development in VCFS (e.g., language development, numerical cognition) is discussed.

Exposure to and recall of violence reduce short-term memory and cognitive control.

Science.gov (United States)

Bogliacino, Francesco; Grimalda, Gianluca; Ortoleva, Pietro; Ring, Patrick

2017-08-08

Previous research has investigated the effects of violence and warfare on individuals' well-being, mental health, and individual prosociality and risk aversion. This study establishes the short- and long-term effects of exposure to violence on short-term memory and aspects of cognitive control. Short-term memory is the ability to store information. Cognitive control is the capacity to exert inhibition, working memory, and cognitive flexibility. Both have been shown to affect positively individual well-being and societal development. We sampled Colombian civilians who were exposed either to urban violence or to warfare more than a decade earlier. We assessed exposure to violence through either the urban district-level homicide rate or self-reported measures. Before undertaking cognitive tests, a randomly selected subset of our sample was asked to recall emotions of anxiety and fear connected to experiences of violence, whereas the rest recalled joyful or emotionally neutral experiences. We found that higher exposure to violence was associated with lower short-term memory abilities and lower cognitive control in the group recalling experiences of violence, whereas it had no effect in the other group. This finding demonstrates that exposure to violence, even if a decade earlier, can hamper cognitive functions, but only among individuals actively recalling emotional states linked with such experiences. A laboratory experiment conducted in Germany aimed to separate the effect of recalling violent events from the effect of emotions of fear and anxiety. Both factors had significant negative effects on cognitive functions and appeared to be independent from each other.

Relationship between short and long term radon measurements

International Nuclear Information System (INIS)

Martinez, T.; Ramirez, D.; Navarrete, M.; Cabrera, L.; Ramirez, A.; Gonzalez, P.

2000-01-01

In this work the radon group of the Faculty of Chemistry at the National University of Mexico presents the results obtained in the establishment of a relation between the short and long term radon measures made with passive electret detectors E-PERM type LLT and HST. The measures were carried out inside single family dwellings (open house condition) located in the southeast of Mexico City (in Xochimilco) during the four seasons of the year 1997. A correlation was established between the short term measures (five days) and those of a long term for every season as well as an annual average, with an equation that relates them. The objective and advantage of this correlation are that with a short term measure it is possible to predict the annual mean radon concentration, that represents a saving of human and economic resources. (author)

Supply security and short-run capacity markets for electricity

International Nuclear Information System (INIS)

Creti, Anna; Fabra, Natalia

2007-01-01

The creation of electricity markets has raised the fundamental question as to whether markets create the right incentives for the provision of the reserves needed to maintain supply security in the short-run, or whether some form of regulation is required. In some states in the US, electricity distributors have been made responsible for providing such reserves by contracting capacity in excess of their forecasted peak demand. The so-called Installed Capacity Markets provide one means of contracting reserves, and are the subject of this paper. Under monopoly as well as under perfect competition, we identify firms' short-run opportunity costs of committing resources in the capacity market and the costs of inducing full capacity commitment. The long-run investment problem is not considered. From a welfare viewpoint, we also compare the desirability of providing reserves either through capacity markets or through the demand side (i.e. power curtailments). At the optimum, capacity obligations equal peak demand (plus expected outages) and the capacity deficiency rate (which serves as a price cap) is set at firms' opportunity costs of providing full capacity commitment. (Author)

Statistical mechanics of neocortical interactions. Derivation of short-term-memory capacity

Science.gov (United States)

Ingber, Lester

1984-06-01

A theory developed by the author to describe macroscopic neocortical interactions demonstrates that empirical values of chemical and electrical parameters of synaptic interactions establish several minima of the path-integral Lagrangian as a function of excitatory and inhibitory columnar firings. The number of possible minima, their time scales of hysteresis and probable reverberations, and their nearest-neighbor columnar interactions are all consistent with well-established empirical rules of human short-term memory. Thus, aspects of conscious experience are derived from neuronal firing patterns, using modern methods of nonlinear nonequilibrium statistical mechanics to develop realistic explicit synaptic interactions.

Order Short-Term Memory Capacity Predicts Nonword Reading and Spelling in First and Second Grade

Science.gov (United States)

Binamé, Florence; Poncelet, Martine

2016-01-01

Recent theories of short-term memory (STM) distinguish between item information, which reflects the temporary activation of long-term representations stored in the language system, and serial-order information, which is encoded in a specific representational system that is independent of the language network. Some studies examining the…

Concrete/Febex Bentonite Interaction: Results On Short-Term Column Experiments

International Nuclear Information System (INIS)

Escribano, A.; Turrero, M.J.; Torres, E.; Martin, P.L.

2008-01-01

Interaction between the alkaline pore fluids from the concrete engineered barriers and the bentonite at the repository conditions may generate products that can diffuse through the porous structure of the bentonite affecting their properties. A comprehensive study based on series of short term experiments is being performed to provide experimental evidences on the physical, chemical and mineralogical changes during the concrete-compacted bentonite interaction. Samples were analyzed by XRD, SEM-EDS and FTIR. Measurements of swelling capacity, specific surface area and chemical analysis for cation exchange capacity and soluble salts analyses were also performed. (authors)

Concrete/Febex Bentonite Interaction: Results On Short-Term Column Experiments

Energy Technology Data Exchange (ETDEWEB)

Escribano, A.; Turrero, M.J.; Torres, E.; Martin, P.L. [CIEMAT, Environmental Department, Avda. Complutense, 22, 28040 Madrid (Spain)

2008-07-01

Interaction between the alkaline pore fluids from the concrete engineered barriers and the bentonite at the repository conditions may generate products that can diffuse through the porous structure of the bentonite affecting their properties. A comprehensive study based on series of short term experiments is being performed to provide experimental evidences on the physical, chemical and mineralogical changes during the concrete-compacted bentonite interaction. Samples were analyzed by XRD, SEM-EDS and FTIR. Measurements of swelling capacity, specific surface area and chemical analysis for cation exchange capacity and soluble salts analyses were also performed. (authors)

Pediatric polytrauma : Short-term and long-term outcomes

NARCIS (Netherlands)

vanderSluis, CK; Kingma, J; Eisma, WH; tenDuis, HJ

Objective: To assess the short-term and long-term outcomes of pediatric polytrauma patients and to analyze the extent to which short-term outcomes can predict long-term outcomes. Materials and Methods: Ail pediatric polytrauma patients (Injury Severity Score of greater than or equal to 16, less than

Is visual short-term memory depthful?

Science.gov (United States)

Reeves, Adam; Lei, Quan

2014-03-01

Does visual short-term memory (VSTM) depend on depth, as it might be if information was stored in more than one depth layer? Depth is critical in natural viewing and might be expected to affect retention, but whether this is so is currently unknown. Cued partial reports of letter arrays (Sperling, 1960) were measured up to 700 ms after display termination. Adding stereoscopic depth hardly affected VSTM capacity or decay inferred from total errors. The pattern of transposition errors (letters reported from an uncued row) was almost independent of depth and cue delay. We conclude that VSTM is effectively two-dimensional. Copyright © 2014 Elsevier Ltd. All rights reserved.

Attentional control constrains visual short-term memory: Insights from developmental and individual differences

Science.gov (United States)

Astle, D.E.; Nobre, A.C.; Scerif, G.

2014-01-01

The mechanisms by which attentional control biases mnemonic representations have attracted much interest but remain poorly understood. As attention and memory develop gradually over childhood and variably across individuals, assessing how participants of different ages and ability attend to mnemonic contents can elucidate their interplay. In Experiment 1, 7-, 10-year-olds and adults were asked to report whether a probe item had been part of a previously presented four-item array. The initial array could either be uncued, preceded (“pre-cued”) or followed (“retro-cued”) by a spatial cue orienting attention to one of the potential item locations. Performance across groups was significantly improved by both cue types and individual differences in children’s retrospective attentional control predicted their visual short-term and working memory span, whereas their basic ability to remember in the absence of cues did not. Experiment 2 imposed a variable delay between the array and the subsequent orienting cue. Cueing benefits were greater in adults compared to 10-year-olds, but they persisted even when cues followed the array by nearly 3 seconds, suggesting that orienting operated on durable short-term representations for both age groups. The findings indicate that there are substantial developmental and individual differences in the ability to control attention to memory and that in turn these differences constrain visual short-term memory capacity. PMID:20680889

Complexities of short-term mobility for sex work and migration among sex workers: violence and sexual risks, barriers to care, and enhanced social and economic opportunities.

Science.gov (United States)

Goldenberg, Shira M; Chettiar, Jill; Nguyen, Paul; Dobrer, Sabina; Montaner, Julio; Shannon, Kate

2014-08-01

Despite research on the health and safety of mobile and migrant populations in the formal and informal sectors globally, limited information is available regarding the working conditions, health, and safety of sex workers who engage in short-term mobility and migration. The objective of this study was to longitudinally examine work environment, health, and safety experiences linked to short-term mobility/migration (i.e., worked or lived in another city, province, or country) among sex workers in Vancouver, Canada, over a 2.5-year study period (2010-2012). We examined longitudinal correlates of short-term mobility/migration (i.e., worked or lived in another city, province, or country over the 3-year follow-up period) among 646 street and off-street sex workers in a longitudinal community-based study (AESHA). Of 646 sex workers, 10.84 % (n = 70) worked or lived in another city, province, or country during the study. In a multivariate generalized estimating equations (GEE) model, short-term mobility/migration was independently correlated with older age (adjusted odds ratio (AOR) 0.95, 95 % confidence interval (CI) 0.92-0.98), soliciting clients in indoor (in-call) establishments (AOR 2.25, 95 % CI 1.27-3.96), intimate partner condom refusal (AOR 3.00, 1.02-8.84), and barriers to health care (AOR 1.77, 95 % CI 1.08-2.89). In a second multivariate GEE model, short-term mobility for sex work (i.e., worked in another city, province, or country) was correlated with client physical/sexual violence (AOR 1.92, 95 % CI 1.02-3.61). In this study, mobile/migrant sex workers were more likely to be younger, work in indoor sex work establishments, and earn higher income, suggesting that short-term mobility for sex work and migration increase social and economic opportunities. However, mobility and migration also correlated with reduced control over sexual negotiation with intimate partners and reduced health care access, and mobility for sex work was associated with

Seat Capacity Selection for an Advanced Short-Haul Aircraft Design

Science.gov (United States)

Marien, Ty V.

2016-01-01

A study was performed to determine the target seat capacity for a proposed advanced short-haul aircraft concept projected to enter the fleet by 2030. This analysis projected the potential demand in the U.S. for a short-haul aircraft using a transportation theory approach, rather than selecting a target seat capacity based on recent industry trends or current market demand. A transportation systems model was used to create a point-to-point network of short-haul trips and then predict the number of annual origin-destination trips on this network. Aircraft of varying seat capacities were used to meet the demand on this network, assuming a single aircraft type for the entire short-haul fleet. For each aircraft size, the ticket revenue and operational costs were used to calculate a total market profitability metric for all feasible flights. The different aircraft sizes were compared, based on this market profitability metric and also the total number of annual round trips and markets served. Sensitivity studies were also performed to determine the effect of changing the aircraft cruise speed and maximum trip length. Using this analysis, the advanced short-haul aircraft design team was able to select a target seat capacity for their design.

Impaired visual short-term memory capacity is distinctively associated with structural connectivity of the posterior thalamic radiation and the splenium of the corpus callosum in preterm-born adults.

Science.gov (United States)

Menegaux, Aurore; Meng, Chun; Neitzel, Julia; Bäuml, Josef G; Müller, Hermann J; Bartmann, Peter; Wolke, Dieter; Wohlschläger, Afra M; Finke, Kathrin; Sorg, Christian

2017-04-15

Preterm birth is associated with an increased risk for lasting changes in both the cortico-thalamic system and attention; however, the link between cortico-thalamic and attention changes is as yet little understood. In preterm newborns, cortico-cortical and cortico-thalamic structural connectivity are distinctively altered, with increased local clustering for cortico-cortical and decreased integrity for cortico-thalamic connectivity. In preterm-born adults, among the various attention functions, visual short-term memory (vSTM) capacity is selectively impaired. We hypothesized distinct associations between vSTM capacity and the structural integrity of cortico-thalamic and cortico-cortical connections, respectively, in preterm-born adults. A whole-report paradigm of briefly presented letter arrays based on the computationally formalized Theory of Visual Attention (TVA) was used to quantify parameter vSTM capacity in 26 preterm- and 21 full-term-born adults. Fractional anisotropy (FA) of posterior thalamic radiations and the splenium of the corpus callosum obtained by diffusion tensor imaging were analyzed by tract-based spatial statistics and used as proxies for cortico-thalamic and cortico-cortical structural connectivity. The relationship between vSTM capacity and cortico-thalamic and cortico-cortical connectivity, respectively, was significantly modified by prematurity. In full-term-born adults, the higher FA in the right posterior thalamic radiation the higher vSTM capacity; in preterm-born adults this FA-vSTM-relationship was inversed. In the splenium, higher FA was correlated with higher vSTM capacity in preterm-born adults, whereas no significant relationship was evident in full-term-born adults. These results indicate distinct associations between cortico-thalamic and cortico-cortical integrity and vSTM capacity in preterm-and full-term-born adults. Data suggest compensatory cortico-cortical fiber re-organization for attention deficits after preterm delivery

The relationship between masking and short-term consolidation during recall from visual working memory.

Science.gov (United States)

Ricker, Timothy J; Sandry, Joshua

2018-04-10

The presentation of a similar but irrelevant stimulus immediately following presentation of a memory item is called masking. Masking is known to reduce performance on working memory tests. This is the type of memory used to hold information in mind for brief periods of time for use in ongoing cognition. Two approaches to understanding masking effects have been proposed in different literatures. Working memory researchers often assume that the reduction in working memory performance after masking is because masking interferes with a transient sensory representation that is needed to complete consolidation into a working memory state. Researchers focused on the attentional blink, a finding that attention cannot be directed to new stimuli during working memory consolidation, have an alternative theory. Attentional blink researchers assume that masking slows the short-term consolidation process, thereby extending the length of the attentional blink. In two experiments, we contrast these two approaches to explaining masking effects and investigate the validity of both hypotheses. Some aspects of both approaches are validated, but neither theoretical perspective alone sufficiently explains the entire pattern of results. © 2018 New York Academy of Sciences.

Long-term associative learning predicts verbal short-term memory performance

OpenAIRE

Jones, Gary; Macken, Bill

2017-01-01

Studies using tests such as digit span and nonword repetition have implicated short-term memory across a range of developmental domains. Such tests ostensibly assess specialized processes for the short-term manipulation and maintenance of information that are often argued to enable long-term learning. However, there is considerable evidence for an influence of long-term linguistic learning on performance in short-term memory tasks that brings into question the role of a specialized short-term...

Long-term associative learning predicts verbal short-term memory performance.

Science.gov (United States)

Jones, Gary; Macken, Bill

2018-02-01

Studies using tests such as digit span and nonword repetition have implicated short-term memory across a range of developmental domains. Such tests ostensibly assess specialized processes for the short-term manipulation and maintenance of information that are often argued to enable long-term learning. However, there is considerable evidence for an influence of long-term linguistic learning on performance in short-term memory tasks that brings into question the role of a specialized short-term memory system separate from long-term knowledge. Using natural language corpora, we show experimentally and computationally that performance on three widely used measures of short-term memory (digit span, nonword repetition, and sentence recall) can be predicted from simple associative learning operating on the linguistic environment to which a typical child may have been exposed. The findings support the broad view that short-term verbal memory performance reflects the application of long-term language knowledge to the experimental setting.

Psychological Mindedness and Psychotherapy Process in Short-Term Group Therapy.

Science.gov (United States)

Kealy, David; Sierra-Hernandez, Carlos A; Piper, William E; Joyce, Anthony S; Weideman, Rene; Ogrodniczuk, John S

2017-01-01

Psychological mindedness is regarded as an important patient characteristic that can influence the course of psychotherapy. The purpose of this study was to investigate the relationship between patients' capacity for psychological mindedness and aspects of the group psychotherapy process as experienced and rated by therapists and other group members. Participants were 110 patients who completed two forms of short-term group therapy for the treatment of complicated grief. Psychological mindedness was assessed at pretreatment by external raters using a video-interview procedure. Group therapists assessed patients' therapeutic work and therapeutic alliance following each group therapy session. Therapists and other group members rated each patient's expression of emotion and provided appraisals of their cohesion to each patient throughout the course of therapy. Psychological mindedness was found to be positively associated with several group process variables as rated by the therapist and other group members.

The strengths and weaknesses in verbal short-term memory and visual working memory in children with hearing impairment and additional language learning difficulties.

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Willis, Suzi; Goldbart, Juliet; Stansfield, Jois

2014-07-01

To compare verbal short-term memory and visual working memory abilities of six children with congenital hearing-impairment identified as having significant language learning difficulties with normative data from typically hearing children using standardized memory assessments. Six children with hearing loss aged 8-15 years were assessed on measures of verbal short-term memory (Non-word and word recall) and visual working memory annually over a two year period. All children had cognitive abilities within normal limits and used spoken language as the primary mode of communication. The language assessment scores at the beginning of the study revealed that all six participants exhibited delays of two years or more on standardized assessments of receptive and expressive vocabulary and spoken language. The children with hearing-impairment scores were significantly higher on the non-word recall task than the "real" word recall task. They also exhibited significantly higher scores on visual working memory than those of the age-matched sample from the standardized memory assessment. Each of the six participants in this study displayed the same pattern of strengths and weaknesses in verbal short-term memory and visual working memory despite their very different chronological ages. The children's poor ability to recall single syllable words in relation to non-words is a clinical indicator of their difficulties in verbal short-term memory. However, the children with hearing-impairment do not display generalized processing difficulties and indeed demonstrate strengths in visual working memory. The poor ability to recall words, in combination with difficulties with early word learning may be indicators of children with hearing-impairment who will struggle to develop spoken language equal to that of their normally hearing peers. This early identification has the potential to allow for target specific intervention that may remediate their difficulties. Copyright © 2014. Published

The prediction of the level of personality organization on reduction of psychiatric symptoms and improvement of work ability in short- versus long-term psychotherapies during a 5-year follow-up.

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Knekt, Paul; Lindfors, Olavi; Keinänen, Matti; Heinonen, Erkki; Virtala, Esa; Härkänen, Tommi

2017-09-01

How level of personality organization (LPO) predicts psychiatric symptoms and work ability in short- versus long-term psychotherapies is poorly known. We investigated the importance of the LPO on the benefits of short-term versus long-term psychotherapies. A cohort study based on 326 outpatients with mood or anxiety disorder was allocated to long-term (LPP) and short-term (SPP) psychodynamic psychotherapy, and solution-focused therapy (SFT). The LPO was assessed by interview at baseline and categorized into neuroses and higher level borderline. Outcome was assessed at baseline and 4-9 times during a 5-year follow-up, using self-report and interview-based measures of symptoms and work ability. For patients receiving SPP, improvement in work ability, symptom reduction, and the remission rate were more considerable in patients with neuroses than in higher level borderline patients, whereas LPP or SFT showed no notable differences in effectiveness in the two LPO groups. In patients with neuroses, improvement was more considerable in the short-term therapy groups during the first year of follow-up, and in higher level borderline patients LPP was more effective after 3 years of follow-up. The remission rate, defined as both symptom reduction and lack of auxiliary treatment, was higher in LPP than in SPP for both the LPO groups considered. In neuroses, short-term psychotherapy was associated with a more rapid reduction of symptoms and increase in work ability, whereas LPP was more effective for longer follow-ups in both LPO groups. Further large-scale studies are needed. Level of personality organization is relevant for selection between short- and long-term psychotherapies. Short-term therapy gives faster benefits for neurotic patients but not for patients with higher level borderline personality organization. Sustained remission from symptoms is more probable after long-term than short-term therapy. © 2016 The British Psychological Society.

Declarative and Procedural Working Memory: Common Principles, Common Capacity Limits?

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Klus Oberauer

2010-10-01

Full Text Available Working memory is often described as a system for simultaneous storage and processing. Much research – and most measures of working-memory capacity – focus on the storage component only, that is, people's ability to recall or recognize items after short retention intervals. The mechanisms of processing information are studied in a separate research tradition, concerned with the selection and control of actions in simple choice situations, dual-task constellations, or task-switching setups. both research traditions investigate performance based on representations that are temporarily maintained in an active, highly accessible state, and constrained by capacity limits. In this article an integrated theoretical framework of declarative and procedural working memory is presented that relates the two domains of research to each other. Declarative working memory is proposed to hold representations available for processing (including recall and recognition, whereas procedural working memory holds representations that control processing (i. e., task sets, stimulus-response mappings, and executive control settings. The framework motivates two hypotheses: Declarative and procedural working memory have separate capacity limits, and they operate by analogous principles. The framework also suggests a new characterization of executive functions as the subset of processes governed by procedural working memory that has as its output a change in the conditions of operation of the working-memory system.

Left TPJ activity in verbal working memory: implications for storage- and sensory-specific models of short term memory.

Science.gov (United States)

Ravizza, Susan M; Hazeltine, Eliot; Ruiz, Sandra; Zhu, David C

2011-04-15

Patients with damage to the left temporoparietal junction (TPJ) have a low verbal span without concomitant deficits in speech perception. This pattern of cognitive impairment is taken as evidence for a dedicated phonological buffer that plays little role in perception (storage-specific account). In contrast, other research suggests that items are maintained and perceived in the same regions (sensory-specific account). In an fMRI study, we demonstrate that the left TPJ does not respond in a way predicted of a phonological buffer; that is, activity in this region is not sustained during encoding or maintenance. Instead, a region in the superior temporal gyrus that has been associated with both speech perception and production demonstrated the expected profile of a store: it was more active in the verbal condition than the object condition and was active during both encoding and maintenance. These results support the sensory-specific account of short term memory rather than the storage-specific account. Based on the pattern of activity in the left TPJ, we suggest that the impairment of verbal working memory observed in patients with TPJ damage may be due to diminished attentional processes rather than reduced storage capacity. Copyright © 2010 Elsevier Inc. All rights reserved.

Mental Capacity and Working Memory in Chemistry: Algorithmic "versus" Open-Ended Problem Solving

Science.gov (United States)

St Clair-Thompson, Helen; Overton, Tina; Bugler, Myfanwy

2012-01-01

Previous research has revealed that problem solving and attainment in chemistry are constrained by mental capacity and working memory. However, the terms mental capacity and working memory come from different theories of cognitive resources, and are assessed using different tasks. The current study examined the relationships between mental…

Effective visual short-term storage capacity and speed of encoding are affected by arousal

DEFF Research Database (Denmark)

Sørensen, Thomas Alrik; Bundesen, Claus

2011-01-01

of encoding into visual short-term memory (VSTM) increased with the level of arousal in a single-stimulus identification experiment. Here we present a whole-report experiment corroborating the finding that speed of encoding stimulus items (letters) into VSTM increases with the level of arousal. However....... Thus, in terms of the TVA model (Bundesen, 1990), partial report experiments should show that, at high levels of arousal, parameter a (the ratio of the attentional weight of a distractor to the attentional weight of a target) increases....

The effect of spatial organization of targets and distractors on the capacity to selectively memorize objects in visual short-term memory.

Science.gov (United States)

Abbes, Aymen Ben; Gavault, Emmanuelle; Ripoll, Thierry

2014-01-01

We conducted a series of experiments to explore how the spatial configuration of objects influences the selection and the processing of these objects in a visual short-term memory task. We designed a new experiment in which participants had to memorize 4 targets presented among 4 distractors. Targets were cued during the presentation of distractor objects. Their locations varied according to 4 spatial configurations. From the first to the last configuration, the distance between targets' locations was progressively increased. The results revealed a high capacity to select and memorize targets embedded among distractors even when targets were extremely distant from each other. This capacity is discussed in relation to the unitary conception of attention, models of split attention, and the competitive interaction model. Finally, we propose that the spatial dispersion of objects has different effects on attentional allocation and processing stages. Thus, when targets are extremely distant from each other, attentional allocation becomes more difficult while processing becomes easier. This finding implicates that these 2 aspects of attention need to be more clearly distinguished in future research.

Visual Short-Term Memory: is Capacity Dependent on Stimulus Complexity?

DEFF Research Database (Denmark)

Sørensen, Thomas Alrik

complexity - which is dependent on the familiarity of a given stimulus - plays a more important role than the objective visual complexity of the objects stored. In several studies, we explored how familiarity influences the capacity of VSTM and our results indicate that VSTM capacity for familiar items...

Are there multiple visual short-term memory stores?

Science.gov (United States)

Sligte, Ilja G; Scholte, H Steven; Lamme, Victor A F

2008-02-27

Classic work on visual short-term memory (VSTM) suggests that people store a limited amount of items for subsequent report. However, when human observers are cued to shift attention to one item in VSTM during retention, it seems as if there is a much larger representation, which keeps additional items in a more fragile VSTM store. Thus far, it is not clear whether the capacity of this fragile VSTM store indeed exceeds the traditional capacity limits of VSTM. The current experiments address this issue and explore the capacity, stability, and duration of fragile VSTM representations. We presented cues in a change-detection task either just after off-set of the memory array (iconic-cue), 1,000 ms after off-set of the memory array (retro-cue) or after on-set of the probe array (post-cue). We observed three stages in visual information processing 1) iconic memory with unlimited capacity, 2) a four seconds lasting fragile VSTM store with a capacity that is at least a factor of two higher than 3) the robust and capacity-limited form of VSTM. Iconic memory seemed to depend on the strength of the positive after-image resulting from the memory display and was virtually absent under conditions of isoluminance or when intervening light masks were presented. This suggests that iconic memory is driven by prolonged retinal activation beyond stimulus duration. Fragile VSTM representations were not affected by light masks, but were completely overwritten by irrelevant pattern masks that spatially overlapped the memory array. We find that immediately after a stimulus has disappeared from view, subjects can still access information from iconic memory because they can see an after-image of the display. After that period, human observers can still access a substantial, but somewhat more limited amount of information from a high-capacity, but fragile VSTM that is overwritten when new items are presented to the eyes. What is left after that is the traditional VSTM store, with a limit of

Are there multiple visual short-term memory stores?

Directory of Open Access Journals (Sweden)

Ilja G Sligte

Full Text Available BACKGROUND: Classic work on visual short-term memory (VSTM suggests that people store a limited amount of items for subsequent report. However, when human observers are cued to shift attention to one item in VSTM during retention, it seems as if there is a much larger representation, which keeps additional items in a more fragile VSTM store. Thus far, it is not clear whether the capacity of this fragile VSTM store indeed exceeds the traditional capacity limits of VSTM. The current experiments address this issue and explore the capacity, stability, and duration of fragile VSTM representations. METHODOLOGY/PRINCIPAL FINDINGS: We presented cues in a change-detection task either just after off-set of the memory array (iconic-cue, 1,000 ms after off-set of the memory array (retro-cue or after on-set of the probe array (post-cue. We observed three stages in visual information processing 1 iconic memory with unlimited capacity, 2 a four seconds lasting fragile VSTM store with a capacity that is at least a factor of two higher than 3 the robust and capacity-limited form of VSTM. Iconic memory seemed to depend on the strength of the positive after-image resulting from the memory display and was virtually absent under conditions of isoluminance or when intervening light masks were presented. This suggests that iconic memory is driven by prolonged retinal activation beyond stimulus duration. Fragile VSTM representations were not affected by light masks, but were completely overwritten by irrelevant pattern masks that spatially overlapped the memory array. CONCLUSIONS/SIGNIFICANCE: We find that immediately after a stimulus has disappeared from view, subjects can still access information from iconic memory because they can see an after-image of the display. After that period, human observers can still access a substantial, but somewhat more limited amount of information from a high-capacity, but fragile VSTM that is overwritten when new items are presented

Ocean Dredged Material Disposal Site (ODMDS) Authorization and Short-Term FATE (STFATE) Model Analysis: 2014-2015 Working Group Findings Report

Science.gov (United States)

2016-03-01

fractions A grain size or sieve analysis typically yields the mass fraction of each particle size class after dispersing all of the material. However...ER D C TR -1 6- 2 Ocean Dredged Material Disposal Site (ODMDS) Authorization and Short-Term FATE (STFATE) Model Analysis 2014 – 2015...Term FATE (STFATE) Model Analysis 2014 – 2015 Working Group Findings Report Jase D. Ousley Coastal and Hydraulics Laboratory U.S. Army Engineer

Impaired short-term memory for pitch in congenital amusia.

Science.gov (United States)

Tillmann, Barbara; Lévêque, Yohana; Fornoni, Lesly; Albouy, Philippe; Caclin, Anne

2016-06-01

Congenital amusia is a neuro-developmental disorder of music perception and production. The hypothesis is that the musical deficits arise from altered pitch processing, with impairments in pitch discrimination (i.e., pitch change detection, pitch direction discrimination and identification) and short-term memory. The present review article focuses on the deficit of short-term memory for pitch. Overall, the data discussed here suggest impairments at each level of processing in short-term memory tasks; starting with the encoding of the pitch information and the creation of the adequate memory trace, the retention of the pitch traces over time as well as the recollection and comparison of the stored information with newly incoming information. These impairments have been related to altered brain responses in a distributed fronto-temporal network, associated with decreased connectivity between these structures, as well as in abnormalities in the connectivity between the two auditory cortices. In contrast, amusic participants׳ short-term memory abilities for verbal material are preserved. These findings show that short-term memory deficits in congenital amusia are specific to pitch, suggesting a pitch-memory system that is, at least partly, separated from verbal memory. This article is part of a Special Issue entitled SI: Auditory working memory. Copyright © 2015 Elsevier B.V. All rights reserved.

Impact of long-term and short-term therapies on seminal parameters

Directory of Open Access Journals (Sweden)

Jlenia Elia

2013-04-01

Full Text Available Aim: The aim of this work was: i to evaluate the prevalence of male partners of subfertile couples being treated with long/short term therapies for non andrological diseases; ii to study their seminal profile for the possible effects of their treatments on spermatogenesis and/or epididymal maturation. Methods: The study group was made up of 723 subjects, aged between 25 and 47 years. Semen analysis was performed according to World Health Organization (WHO guidelines (1999. The Superimposed Image Analysis System (SIAS, which is based on the computerized superimposition of spermatozoa images, was used to assess sperm motility parameters. Results: The prevalence of subjects taking pharmacological treatments was 22.7% (164/723. The prevalence was 3.7% (27/723 for the Short-Term Group and 18.9% (137/723 for the Long-Term Group. The subjects of each group were also subdivided into subgroups according to the treatments being received. Regarding the seminal profile, we did not observe a significant difference between the Long-Term, Short-Term or the Control Group. However, regarding the subgroups, we found a significant decrease in sperm number and progressive motility percentage in the subjects receiving treatment with antihypertensive drugs compared with the other subgroups and the Control Group. Conclusions: In the management of infertile couples, the potential negative impact on seminal parameters of any drugs being taken as Long-Term Therapy should be considered. The pathogenic mechanism needs to be clarified.

Tone Series and the Nature of Working Memory Capacity Development

Science.gov (United States)

Clark, Katherine M.; Hardman, Kyle O.; Schachtman, Todd R.; Saults, J. Scott; Glass, Bret A.; Cowan, Nelson

2018-01-01

Recent advances in understanding visual working memory, the limited information held in mind for use in ongoing processing, are extended here to examine auditory working memory development. Research with arrays of visual objects has shown how to distinguish the capacity, in terms of the "number" of objects retained, from the…

Haploinsufficiency of the 22q11.2 microdeletion gene Mrpl40 disrupts short-term synaptic plasticity and working memory through dysregulation of mitochondrial calcium.

Science.gov (United States)

Devaraju, P; Yu, J; Eddins, D; Mellado-Lagarde, M M; Earls, L R; Westmoreland, J J; Quarato, G; Green, D R; Zakharenko, S S

2017-09-01

Hemizygous deletion of a 1.5- to 3-megabase region on chromosome 22 causes 22q11.2 deletion syndrome (22q11DS), which constitutes one of the strongest genetic risks for schizophrenia. Mouse models of 22q11DS have abnormal short-term synaptic plasticity that contributes to working-memory deficiencies similar to those in schizophrenia. We screened mutant mice carrying hemizygous deletions of 22q11DS genes and identified haploinsufficiency of Mrpl40 (mitochondrial large ribosomal subunit protein 40) as a contributor to abnormal short-term potentiation (STP), a major form of short-term synaptic plasticity. Two-photon imaging of the genetically encoded fluorescent calcium indicator GCaMP6, expressed in presynaptic cytosol or mitochondria, showed that Mrpl40 haploinsufficiency deregulates STP via impaired calcium extrusion from the mitochondrial matrix through the mitochondrial permeability transition pore. This led to abnormally high cytosolic calcium transients in presynaptic terminals and deficient working memory but did not affect long-term spatial memory. Thus, we propose that mitochondrial calcium deregulation is a novel pathogenic mechanism of cognitive deficiencies in schizophrenia.

Functional connectivity among multi-channel EEGs when working memory load reaches the capacity.

Science.gov (United States)

Zhang, Dan; Zhao, Huipo; Bai, Wenwen; Tian, Xin

2016-01-15

Evidence from behavioral studies has suggested a capacity existed in working memory. As the concept of functional connectivity has been introduced into neuroscience research in the recent years, the aim of this study is to investigate the functional connectivity in the brain when working memory load reaches the capacity. 32-channel electroencephalographs (EEGs) were recorded for 16 healthy subjects, while they performed a visual working memory task with load 1-6. Individual working memory capacity was calculated according to behavioral results. Short-time Fourier transform was used to determine the principal frequency band (theta band) related to working memory. The functional connectivity among EEGs was measured by the directed transform function (DTF) via spectral Granger causal analysis. The capacity was 4 calculated from the behavioral results. The power was focused in the frontal midline region. The strongest connectivity strengths of EEG theta components from load 1 to 6 distributed in the frontal midline region. The curve of DTF values vs load numbers showed that DTF increased from load 1 to 4, peaked at load 4, then decreased after load 4. This study finds that the functional connectivity between EEGs, described quantitatively by DTF, became less strong when working memory load exceeded the capacity. Copyright © 2015 Elsevier B.V. All rights reserved.

Massed versus Spaced Practice in Vocology: Effect of a Short-Term Intensive Voice Training versus a Longer-Term Traditional Voice Training

Science.gov (United States)

Meerschman, Iris; Van Lierde, Kristiane; Van Puyvelde, Caro; Bostyn, Astrid; Claeys, Sofie; D'haeseleer, Evelien

2018-01-01

Background: In contrast with most medical and pharmaceutical therapies, the optimal dosage for voice therapy or training is unknown. Aims: The aim of this study was to compare the effect of a short-term intensive voice training (IVT) with a longer-term traditional voice training (TVT) on the vocal quality and vocal capacities of vocally healthy…

Verbal short-term memory in individuals with chromosome 22q11.2 deletion: Specific deficit in serial order retention capacities?

OpenAIRE

Majerus, Steve; Van der Linden, Martial; Braissand, V.; Eliez, S.

2007-01-01

Many researchers have recently explored the cognitive profile of velocardiofacial syndrome (VCFS), a neurodevelopmental disorder linked to a 22q11.2 deletion. However, verbal short-term memory has not yet been systematically investigated. We explored verbal short-term memory abilities in a group of 11 children and adults presenting with VCFS and two control groups, matched on either CA or vocabulary knowledge, by distinguishing short-term memory for serial order and item information. The VCFS...

Prevalence and diagnostic validity of motivational impairments and deficits in visuospatial short-term memory and working memory in ADHD subtypes

NARCIS (Netherlands)

Dovis, S.; van der Oord, S.; Huizenga, H.M.; Wiers, R.W.; Prins, P.J.M.

2015-01-01

Deficits in working memory (WM) and reinforcement sensitivity are thought to give rise to symptoms in the combined (ADHD-C) and inattentive subtype (ADHD-I) of ADHD. Children with ADHD are especially impaired on visuospatial WM, which is composed of short-term memory (STM) and a central executive.

Aspects if stochastic models for short-term hydropower scheduling and bidding

Energy Technology Data Exchange (ETDEWEB)

Belsnes, Michael Martin [Sintef Energy, Trondheim (Norway); Follestad, Turid [Sintef Energy, Trondheim (Norway); Wolfgang, Ove [Sintef Energy, Trondheim (Norway); Fosso, Olav B. [Dep. of electric power engineering NTNU, Trondheim (Norway)

2012-07-01

This report discusses challenges met when turning from deterministic to stochastic decision support models for short-term hydropower scheduling and bidding. The report describes characteristics of the short-term scheduling and bidding problem, different market and bidding strategies, and how a stochastic optimization model can be formulated. A review of approaches for stochastic short-term modelling and stochastic modelling for the input variables inflow and market prices is given. The report discusses methods for approximating the predictive distribution of uncertain variables by scenario trees. Benefits of using a stochastic over a deterministic model are illustrated by a case study, where increased profit is obtained to a varying degree depending on the reservoir filling and price structure. Finally, an approach for assessing the effect of using a size restricted scenario tree to approximate the predictive distribution for stochastic input variables is described. The report is a summary of the findings of Work package 1 of the research project #Left Double Quotation Mark#Optimal short-term scheduling of wind and hydro resources#Right Double Quotation Mark#. The project aims at developing a prototype for an operational stochastic short-term scheduling model. Based on the investigations summarized in the report, it is concluded that using a deterministic equivalent formulation of the stochastic optimization problem is convenient and sufficient for obtaining a working prototype. (author)

EEG markers of reduced visual short-term memory capacity in adult attention deficit/hyperactivity disorder

DEFF Research Database (Denmark)

Wiegand, Iris Michaela; Kilian, Beate; Hennig-Fast, Kristina

2015-01-01

Attention deficit hyperactivity disorder (ADHD) persists frequently into adulthood. The disease is associated with difficulties in many cognitive tasks, which are assumed to be caused by neurobiologically-based basal dysfunctions. A reduction in visual working memory storage capacity has recently...... been claimed a testable endophenotype of ADHD. This study aimed at identifying brain abnormalities underlying this deficit by combining parameter-based assessment with electrophysiology. We compared unmedicated adult ADHD patients and demographically matched, healthy controls. We found reduced storage...... capacity in the patient group and delineated neural correlates of the deficit by analyzing ERP amplitudes according to (1) differences between patients and controls and (2) individual’s performance level of storage capacity K: First, the contralateral delay activity (CDA) was higher for individuals...

Pro short-term procurement - Broker/trader

International Nuclear Information System (INIS)

Hoellen, E.E.

1990-01-01

The author presents his opinion on the issue of short-term versus long-term procurement of uranium and enrichment and the impact on reliability of supply. The progression of the market has been one of increasing commoditization. Utility buyers have moved towards purchasing uranium on the spot market and linking long-term contracts to spot-market pricing. There is some logic to the argument that utilities and the industry in general would be best served by this approach. Inventories would be worked off much more quickly, and unnecessary supply would be shut off until prices recovered to profitable levels. The result would be a healthier market with no detriment to the reliability of supply

Verbal short-term memory span in children: long-term modality dependent effects of intrauterine growth restriction.

Science.gov (United States)

Geva, R; Eshel, R; Leitner, Y; Fattal-Valevski, A; Harel, S

2008-12-01

Recent reports showed that children born with intrauterine growth restriction (IUGR) are at greater risk of experiencing verbal short-term memory span (STM) deficits that may impede their learning capacities at school. It is still unknown whether these deficits are modality dependent. This long-term, prospective design study examined modality-dependent verbal STM functions in children who were diagnosed at birth with IUGR (n = 138) and a control group (n = 64). Their STM skills were evaluated individually at 9 years of age with four conditions of the Visual-Aural Digit Span Test (VADS; Koppitz, 1981): auditory-oral, auditory-written, visuospatial-oral and visuospatial-written. Cognitive competence was evaluated with the short form of the Wechsler Intelligence Scales for Children--revised (WISC-R95; Wechsler, 1998). We found IUGR-related specific auditory-oral STM deficits (p long-term relationship between prenatal aberrant head growth and auditory verbal STM deficits by the end of the first decade of life. Empirical, clinical and educational implications are presented.

Memory for relations in the short term and the long term after medial temporal lobe damage.

Science.gov (United States)

Squire, Larry R

2017-05-01

A central idea about the organization of declarative memory and the function of the hippocampus is that the hippocampus provides for the coding of relationships between items. A question arises whether this idea refers to the process of forming long-term memory or whether, as some studies have suggested, memory for relations might depend on the hippocampus even at short retention intervals and even when the task falls within the province of short-term (working) memory. The latter formulation appears to place the operation of relational memory into conflict with the idea that working memory is independent of medial temporal lobe (MTL) structures. In this report, the concepts of relational memory and working memory are discussed in the light of a simple demonstration experiment. Patients with MTL lesions successfully learned and recalled two word pairs when tested directly after learning but failed altogether when tested after a delay. The results do not contradict the idea that the hippocampus has a fundamental role in relational memory. However, there is a need for further elaboration and specification of the idea in order to explain why patients with MTL lesions can establish relational memory in the short term but not in long-term memory. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Effects of aging on muscle mechanical function and muscle fiber morphology during short-term immobilization and subsequent retraining

DEFF Research Database (Denmark)

Hvid, Lars; Aagaard, Per; Justesen, Lene

2010-01-01

Very little attention has been given to the combined effects of aging and disuse as separate factors causing deterioration in muscle mechanical function. Thus the purpose of this study was to investigate the effects of 2 wk of immobilization followed by 4 wk of retraining on knee extensor muscle...... to the deleterious effects of short-term muscle disuse on muscle fiber size and rapid force capacity than YM. Furthermore, OM seems to require longer time to recover and regain rapid muscle force capacity, which may lead to a larger risk of falling in aged individuals after periods of short-term disuse....

Short-term visual memory properties sheet secondary school age with different levels of physical development

Directory of Open Access Journals (Sweden)

E.E. Menshikh

2013-12-01

Full Text Available Purpose . The results presented properties of short-term visual memory with different levels of physical development. Materials and methods. The study included 405 boys and girls Cherkassy school 11 in age from 13 to 16 years. Study of short-term visual memory was carried out using tables with 10 characters ( numbers and ambiguous geometric shapes . Indicator memory was the higher, the more information was displayed. Measured the length and body weight was recorded cardiorespiratory indicators - heart rate at rest and after 20 squats, lung capacity, breath-hold inspiration and expiration. Physical development factor was calculated by taking into account actual and average population indices. Results . Found that the volume of short-term visual memory, the boys and girls high school age does not depend on the level of their physical development. Despite the fact that the trend towards higher performance memory in groups of persons with a high level of physical development compared to their same age with medium and low levels, significant differences between the mean values for the most part have been identified. No significant differences between the values of the investigated cognitive function in groups by sex. Conclusions . Growth pattern memory with age in this period of ontogenesis preserved that coincides with the data presented in the scientific works of scientists.

Auditory short-term memory in the primate auditory cortex

OpenAIRE

Scott, Brian H.; Mishkin, Mortimer

2015-01-01

Sounds are fleeting, and assembling the sequence of inputs at the ear into a coherent percept requires auditory memory across various time scales. Auditory short-term memory comprises at least two components: an active ���working memory��� bolstered by rehearsal, and a sensory trace that may be passively retained. Working memory relies on representations recalled from long-term memory, and their rehearsal may require phonological mechanisms unique to humans. The sensory component, passive sho...

The effect of zinc supplementation of lactating rats on short-term and long-term memory of their male offspring.

Science.gov (United States)

Karami, Mohammad; Ehsanivostacolaee, Simin; Moazedi, Ali Ahmad; Nosrati, Anahita

2013-01-01

In this study the effect of zinc chloride (ZnCl2) administration on the short-term and long-term memory of rats were assessed. We enrolled six groups of adult female and control group of eight Wistar rats in each group. One group was control group with free access to food and water, and five groups drunk zinc chloride in different doses (20, 30, 50, 70 and 100 mg/kg/day) in drinking water for two weeks during lactation .One month after birth, a shuttle box used to short- term and long-term memory and the latency in entering the dark chamber as well. This experiment showed that maternal 70 mg/kg dietary zinc during lactation influenced the working memory of rats' offspring in all groups. Rats received 100 mg/kg/day zinc during lactation so they had significant impairment in working memory (short-term) of their offspring (Plong-term) memory of all groups. Drug consumption below70 mg/kg/day zinc chloride during lactation had no effect. While enhanced 100 mg/ kg/ day zinc in lactating rats could cause short-term memory impairment.

The working memory networks of the human brain.

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Linden, David E J

2007-06-01

Working memory and short-term memory are closely related in their cognitive architecture, capacity limitations, and functional neuroanatomy, which only partly overlap with those of long-term memory. The author reviews the functional neuroimaging literature on the commonalities and differences between working memory and short-term memory and the interplay of areas with modality-specific and supramodal representations in the brain networks supporting these fundamental cognitive processes. Sensory stores in the visual, auditory, and somatosensory cortex play a role in short-term memory, but supramodal parietal and frontal areas are often recruited as well. Classical working memory operations such as manipulation, protection against interference, or updating almost certainly require at least some degree of prefrontal support, but many pure maintenance tasks involve these areas as well. Although it seems that activity shifts from more posterior regions during encoding to more anterior regions during delay, some studies reported sustained delay activity in sensory areas as well. This spatiotemporal complexity of the short-term memory/working memory networks is mirrored in the activation patterns that may explain capacity constraints, which, although most prominent in the parietal cortex, seem to be pervasive across sensory and premotor areas. Finally, the author highlights open questions for cognitive neuroscience research of working memory, such as that of the mechanisms for integrating different types of content (binding) or those providing the link to long-term memory.

Conceptual short term memory in perception and thought.

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Potter, Mary C

2012-01-01

Conceptual short term memory (CSTM) is a theoretical construct that provides one answer to the question of how perceptual and conceptual processes are related. CSTM is a mental buffer and processor in which current perceptual stimuli and their associated concepts from long term memory (LTM) are represented briefly, allowing meaningful patterns or structures to be identified (Potter, 1993, 1999, 2009). CSTM is different from and complementary to other proposed forms of working memory: it is engaged extremely rapidly, has a large but ill-defined capacity, is largely unconscious, and is the basis for the unreflective understanding that is characteristic of everyday experience. The key idea behind CSTM is that most cognitive processing occurs without review or rehearsal of material in standard working memory and with little or no conscious reasoning. When one perceives a meaningful stimulus such as a word, picture, or object, it is rapidly identified at a conceptual level and in turn activates associated information from LTM. New links among concurrently active concepts are formed in CSTM, shaped by parsing mechanisms of language or grouping principles in scene perception and by higher-level knowledge and current goals. The resulting structure represents the gist of a picture or the meaning of a sentence, and it is this structure that we are conscious of and that can be maintained in standard working memory and consolidated into LTM. Momentarily activated information that is not incorporated into such structures either never becomes conscious or is rapidly forgotten. This whole cycle - identification of perceptual stimuli, memory recruitment, structuring, consolidation in LTM, and forgetting of non-structured material - may occur in less than 1 s when viewing a pictured scene or reading a sentence. The evidence for such a process is reviewed and its implications for the relation of perception and cognition are discussed.

Differences in brain morphology and working memory capacity across childhood.

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Bathelt, Joe; Gathercole, Susan E; Johnson, Amy; Astle, Duncan E

2018-05-01

Working memory (WM) skills are closely associated with learning progress in key areas such as reading and mathematics across childhood. As yet, however, little is known about how the brain systems underpinning WM develop over this critical developmental period. The current study investigated whether and how structural brain correlates of components of the working memory system change over development. Verbal and visuospatial short-term and working memory were assessed in 153 children between 5.58 and 15.92 years, and latent components of the working memory system were derived. Fractional anisotropy and cortical thickness maps were derived from T1-weighted and diffusion-weighted MRI and processed using eigenanatomy decomposition. There was a greater involvement of the corpus callosum and posterior temporal white matter in younger children for performance associated with the executive part of the working memory system. For older children, this was more closely linked with the thickness of the occipitotemporal cortex. These findings suggest that increasing specialization leads to shifts in the contribution of neural substrates over childhood, moving from an early dependence on a distributed system supported by long-range connections to later reliance on specialized local circuitry. Our findings demonstrate that despite the component factor structure being stable across childhood, the underlying brain systems supporting working memory change. Taking the age of the child into account, and not just their overall score, is likely to be critical for understanding the nature of the limitations on their working memory capacity. © 2017 The Authors. Developmental Science Published by John Wiley & Sons Ltd.

The left superior temporal gyrus is a shared substrate for auditory short-term memory and speech comprehension: evidence from 210 patients with stroke

OpenAIRE

Leff, Alexander P.; Schofield, Thomas M.; Crinion, Jennifer T.; Seghier, Mohamed L.; Grogan, Alice; Green, David W.; Price, Cathy J.

2009-01-01

Competing theories of short-term memory function make specific predictions about the functional anatomy of auditory short-term memory and its role in language comprehension. We analysed high-resolution structural magnetic resonance images from 210 stroke patients and employed a novel voxel based analysis to test the relationship between auditory short-term memory and speech comprehension. Using digit span as an index of auditory short-term memory capacity we found that the structural integrit...

Effect of zinc supplementation of pregnant rats on short-term and long-term memory of their offspring

International Nuclear Information System (INIS)

Ali, M.A.; Ghotbeddin, Z.; Parham, G.H.

2007-01-01

To see the dose dependent effects of zinc chloride on the short-term and long-term memory in a shuttle box (rats). Six pair adult wistar rats were taken for this experiment. One group of pregnant rats received a daily oral dose of 20 mg/kg Zn as zinc chloride and the remaining groups received a daily oral dose of (30, 50, 70,100 mg/kg) zinc chloride for two weeks by gavage. One month after birth, a shuttle box was used to test short-term and long-term memory. Two criteria were considered to behavioral test, including latency in entering dark chamber and time spent in the dark chamber. This experiment showed that oral administration of ZnCl/sub 2/ with (20, 30, 50 mg/kg/day) doses after 2 weeks at the stage of pregnancy, can improve the working memory of their offspring (p<0.05). Where as ZnCl/sub 2/ with 30 mg/kg/day dose has been more effective than other doses (p<0.001). But rat which received ZnCl/sub 2/ with 100 mg/kg/day at the stage of pregnancy, has shown significant impairment in working (short-term) memory of their offspring (p<0.05) and there was no significant difference in reference (long-term) memory 3 for any of groups. This study has demonstrated that zinc chloride consumption with 30 mg/kg/day dose for two weeks at the stage of pregnancy in rats, has positive effect on short-term memory on their offspring. But consumption of enhanced zinc 100 mg/kg/day in pregnant rats can cause short-term memory impairment. On the other hand, zinc supplementation such as zinc chloride has no effect on long-term memory. (author)

Short-term effects of night shift work on breast cancer risk; a cohort study of payroll data

DEFF Research Database (Denmark)

Vistisen, Helene Tilma; Garde, Anne Helene; Frydenberg, Morten

2017-01-01

were followed from 2007-2012. Day-to-day work-hour information was available from payroll registers and 1245 incident cases of breast cancer were identified in national cancer registries together with receptor subtype information. Results: A rate ratio (RR) of 0.90 [95% confidence interval (95% CI) 0......Objectives: The objective was to examine if night shift work is a short-term risk factor for breast cancer, including combined estrogen receptor (ER) and human epidermal growth factor 2 (HER2) breast cancer subtypes. Methods: The cohort comprised 155 540 public sector female workers in Denmark who.......80-1.01] was observed for workers ever working night shifts during the follow-up period compared with workers only working day shifts after adjustment for age, age at first child, parity, family history of breast or ovarian cancer, sex hormones, medications related to alcoholism, family educational level, mammography...

Are there multiple visual short-term memory stores?

NARCIS (Netherlands)

Sligte, I.G.; Scholte, H.S.; Lamme, V.A.F.

2008-01-01

Background: Classic work on visual short-term memory (VSTM) suggests that people store a limited amount of items for subsequent report. However, when human observers are cued to shift attention to one item in VSTM during retention, it seems as if there is a much larger representation, which keeps

Short- and long-term changes in perceived work ability after interdisciplinary rehabilitation of chronic musculoskeletal disorders: prospective cohort study among 854 rehabilitants.

Science.gov (United States)

Saltychev, Mikhail; Laimi, Katri; Pentti, Jaana; Kivimäki, Mika; Vahtera, Jussi

2014-06-01

To investigate the changes in rehabilitants' perceived work ability after rehabilitation for chronic musculoskeletal disorders with respect to the baseline characteristics. Prospective cohort study based on register and repeated survey data. Public sector employees in ten towns and five hospital districts. A total of 854 employees who participated in the rehabilitation programme owing to common chronic musculoskeletal disorders between 1997 and 2009. Interdisciplinary, biopsychosocial, inpatient rehabilitation programme targeting people of working age with common chronic musculoskeletal disorders. The programme was executed in different rehabilitation centres across the country and funded by the Social Insurance Institution of Finland. Differences in perceived work ability level before and after rehabilitation. Data were derived from repeated surveys on average 2.1 years before rehabilitation, and 1.5 years (short-term follow-up) and 6.0 years (long-term follow-up) after rehabilitation. Before the rehabilitation, perceived work ability was 7.13 (SD 1.84) among the rehabilitants and 7.27 (SD 1.72) in the matched reference population. Among rehabilitants, this figure decreased by 0.82 (95% confidence interval -0.98 to -0.67) in the short-term and by 1.26 (95% confidence interval -1.45 to -1.07) in the long-term follow-up. Only slight differences in steepness of this deterioration were observed between subgroups, created based on the participants' baseline characteristics. Perceived work ability of participants, in an interdisciplinary biopsychosocial rehabilitation programme for common musculoskeletal disorders, deteriorated regardless of any studied pretreatment characteristics. The improvement of work ability may be an unrealistic goal for participants in this type of rehabilitation. © The Author(s) 2014.

The Effect of Zinc Supplementation of Lactating Rats on Short-Term and Long-Term Memory of Their Male Offspring

Directory of Open Access Journals (Sweden)

Mohammad Karami

2013-12-01

Full Text Available Background: In this study the effect of zinc chloride (ZnCl2 administration on the short-term and long-term memory of rats were assessed. Methods: We enrolled six groups of adult female and control group of eight Wistar rats in each group. One group was control group with free access to food and water, and five groups drunk zinc chloride in different doses (20, 30, 50, 70 and 100 mg/kg/day in drinking water for two weeks during lactation .One month after birth, a shuttle box used to short- term and long-term memory and the latency in entering the dark chamber as well. Results: This experiment showed that maternal 70 mg/kg dietary zinc during lactation influenced the working memory of rats’ offspring in all groups. Rats received 100 mg/kg/day zinc during lactation so they had significant impairment in working memory (short-term of their offspring (P<0.05. There was no significant difference in reference (long-term memory of all groups. Conclusion: Drug consumption below70 mg/kg/day zinc chloride during lactation had no effect. While enhanced 100 mg/ kg/ day zinc in lactating rats could cause short-term memory impairment.

Spatiotemporal Proximity Effects in Visual Short-Term Memory Examined by Target-Nontarget Analysis

Science.gov (United States)

Sapkota, Raju P.; Pardhan, Shahina; van der Linde, Ian

2016-01-01

Visual short-term memory (VSTM) is a limited-capacity system that holds a small number of objects online simultaneously, implying that competition for limited storage resources occurs (Phillips, 1974). How the spatial and temporal proximity of stimuli affects this competition is unclear. In this 2-experiment study, we examined the effect of the…

Impact of Auditory Selective Attention on Verbal Short-Term Memory and Vocabulary Development

Science.gov (United States)

Majerus, Steve; Heiligenstein, Lucie; Gautherot, Nathalie; Poncelet, Martine; Van der Linden, Martial

2009-01-01

This study investigated the role of auditory selective attention capacities as a possible mediator of the well-established association between verbal short-term memory (STM) and vocabulary development. A total of 47 6- and 7-year-olds were administered verbal immediate serial recall and auditory attention tasks. Both task types probed processing…

Effects of aging on muscle mechanical function and muscle fiber morphology during short-term immobilization and subsequent retraining

DEFF Research Database (Denmark)

Hvid, Lars; Aagaard, Per; Justesen, Lene

2010-01-01

to the deleterious effects of short-term muscle disuse on muscle fiber size and rapid force capacity than YM. Furthermore, OM seems to require longer time to recover and regain rapid muscle force capacity, which may lead to a larger risk of falling in aged individuals after periods of short-term disuse.......Very little attention has been given to the combined effects of aging and disuse as separate factors causing deterioration in muscle mechanical function. Thus the purpose of this study was to investigate the effects of 2 wk of immobilization followed by 4 wk of retraining on knee extensor muscle...... mechanical function (e.g., maximal strength and rapid force capacity) and muscle fiber morphology in 9 old (OM: 67.3 ± 1.3 yr) and 11 young healthy men (YM: 24.4 ± 0.5 yr) with comparable levels of physical activity. Following immobilization, OM demonstrated markedly larger decreases in rapid force capacity...

Working Memory Capacity and Recall from Long-Term Memory: Examining the Influences of Encoding Strategies, Study Time Allocation, Search Efficiency, and Monitoring Abilities

Science.gov (United States)

Unsworth, Nash

2016-01-01

The relation between working memory capacity (WMC) and recall from long-term memory (LTM) was examined in the current study. Participants performed multiple measures of delayed free recall varying in presentation duration and self-reported their strategy usage after each task. Participants also performed multiple measures of WMC. The results…

Short-term forecasting model for aggregated regional hydropower generation

International Nuclear Information System (INIS)

Monteiro, Claudio; Ramirez-Rosado, Ignacio J.; Fernandez-Jimenez, L. Alfredo

2014-01-01

Highlights: • Original short-term forecasting model for the hourly hydropower generation. • The use of NWP forecasts allows horizons of several days. • New variable to represent the capacity level for generating hydroelectric energy. • The proposed model significantly outperforms the persistence model. - Abstract: This paper presents an original short-term forecasting model of the hourly electric power production for aggregated regional hydropower generation. The inputs of the model are previously recorded values of the aggregated hourly production of hydropower plants and hourly water precipitation forecasts using Numerical Weather Prediction tools, as well as other hourly data (load demand and wind generation). This model is composed of three modules: the first one gives the prediction of the “monthly” hourly power production of the hydropower plants; the second module gives the prediction of hourly power deviation values, which are added to that obtained by the first module to achieve the final forecast of the hourly hydropower generation; the third module allows a periodic adjustment of the prediction of the first module to improve its BIAS error. The model has been applied successfully to the real-life case study of the short-term forecasting of the aggregated hydropower generation in Spain and Portugal (Iberian Peninsula Power System), achieving satisfactory results for the next-day forecasts. The model can be valuable for agents involved in electricity markets and useful for power system operations

Effect of Short-Term Hypergravity Treatment on Mouse 2-Cell Embryo Development

Science.gov (United States)

Ning, Li-Na; Lei, Xiao-Hua; Cao, Yu-Jing; Zhang, Yun-Fang; Cao, Zhong-Hong; Chen, Qi; Duan, En-Kui

2015-11-01

Though there are numerous biological experiments, which have been performed in a space environment, to study the physiological effect of space travel on living organisms, while the potential effect of weightlessness or short-term hypergravity on the reproductive system in most species, particularly in mammalian is still controversial and unclear. In our previous study, we investigated the effect of space microgravity on the development of mouse 4-cell embryos by using Chinese SJ-8. .Unexpectedly, we did not get any developed embryo during the space-flight. Considering that the process of space experiment is quite different from most experiments done on earth in several aspects such as, the vibration and short-term hypergravity during the rock launching and landing. Thus we want to know whether the short-term hypergravity produced by the launch process affect the early embryo development in mice, and howthe early embryos respond to the hypergravity. In present study, we are mimicking the short-term hypergravity during launch by using a centrifuge to investigate its influence on the development of early embryo (2-cell) in mice. We also examined the actin filament distribution in 2-cell embryos by immunostaining to test their potential capacity of development under short-term hypergravity exposure. Our results showed that most 2-cell embryos in the hypergravity exposure groups developed into blastocysts with normal morphology after 72h cultured in vitro, and there is no obvious difference in the development rate of blastocyst formation compared to the control. Moreover, there were no statistically significant differences in birth rates after oviduct transfer of 2-cell mouse embryos exposed on short-term hypergravity compared with 1 g condition. In addition, the well-organized actin distribution appeared in 2-cell embryos after exposed on hypergravity and also in the subsequent developmental blastocysts. Taken together, our data shows that short-term exposure in

Guidelines for responsible short-term global health activities: developing common principles.

Science.gov (United States)

Lasker, Judith N; Aldrink, Myron; Balasubramaniam, Ramaswami; Caldron, Paul; Compton, Bruce; Evert, Jessica; Loh, Lawrence C; Prasad, Shailendra; Siegel, Shira

2018-02-07

Growing concerns about the value and effectiveness of short-term volunteer trips intending to improve health in underserved Global South communities has driven the development of guidelines by multiple organizations and individuals. These are intended to mitigate potential harms and maximize benefits associated with such efforts. This paper analyzes 27 guidelines derived from a scoping review of the literature available in early 2017, describing their authorship, intended audiences, the aspects of short term medical missions (STMMs) they address, and their attention to guideline implementation. It further considers how these guidelines relate to the desires of host communities, as seen in studies of host country staff who work with volunteers. Existing guidelines are almost entirely written by and addressed to educators and practitioners in the Global North. There is broad consensus on key principles for responsible, effective, and ethical programs--need for host partners, proper preparation and supervision of visitors, needs assessment and evaluation, sustainability, and adherence to pertinent legal and ethical standards. Host country staff studies suggest agreement with the main elements of this guideline consensus, but they add the importance of mutual learning and respect for hosts. Guidelines must be informed by research and policy directives from host countries that is now mostly absent. Also, a comprehensive strategy to support adherence to best practice guidelines is needed, given limited regulation and enforcement capacity in host country contexts and strong incentives for involved stakeholders to undertake or host STMMs that do not respect key principles.

Investigating Executive Working Memory and Phonological Short-Term Memory in Relation to Fluency and Self-Repair Behavior in L2 Speech

Science.gov (United States)

Georgiadou, Effrosyni; Roehr-Brackin, Karen

2017-01-01

This paper reports the findings of a study investigating the relationship of executive working memory (WM) and phonological short-term memory (PSTM) to fluency and self-repair behavior during an unrehearsed oral task performed by second language (L2) speakers of English at two levels of proficiency, elementary and lower intermediate. Correlational…

Short-term Mobility and Increased Partnership Concurrency among Men in Zimbabwe.

Directory of Open Access Journals (Sweden)

Susan Cassels

Full Text Available Migration has long been understood as an underlying factor for HIV transmission, and sexual partner concurrency has been increasingly studied as an important component of HIV transmission dynamics. However, less work has examined the role of short-term mobility in sexual partner concurrency using a network approach. Short-term mobility may be a risk for HIV for the migrant's partner as well either through the partner's risk behaviors while the migrant is away, such as the partner having additional partners, or via exposure to the return migrant.Using data from the 2010-11 Zimbabwe Demographic and Health Survey, weighted generalized linear regression models were used to investigate the associations between short-term mobility and partnership concurrency at the individual and partnership levels.At the individual level, we find strong evidence of an association between short-term mobility and concurrency. Men who traveled were more likely to have concurrent partnerships compared to men who did not travel and the relationship was non-linear: each trip was associated with a 2% higher probability of concurrency, with a diminishing risk at 60 trips (p<0.001. At the partnership level, short-term mobility by the male only or both partners was associated with male concurrency. Couples in which the female only traveled exhibited less male concurrency.Short-term mobility has the ability to impact population-level transmission dynamics by facilitating partnership concurrency and thus onward HIV transmission. Short-term migrants may be an important population to target for HIV testing, treatment, or social and behavioral interventions to prevent the spread of HIV.

Why chunking should be considered as an explanation for developmental change before short-term memory capacity and processing speed

Directory of Open Access Journals (Sweden)

Gary eJones

2012-06-01

Full Text Available The chunking hypothesis suggests that during the repeated exposure of stimulus material, information is organized into increasingly larger chunks. Many researchers have not considered the full power of the chunking hypothesis as both a learning mechanism and as an explanation of human behavior. Indeed, in developmental psychology there is relatively little mention of chunking and yet it can be the underlying cause of some of the mechanisms of development that have been proposed. This paper illustrates the chunking hypothesis in the domain of nonword repetition, a task that is a strong predictor of a child’s language learning. A computer simulation of nonword repetition that instantiates the chunking mechanism shows that: (1 chunking causes task behavior to improve over time, consistent with children’s performance; and (2 chunking causes perceived changes in areas such as short-term memory capacity and processing speed that are often cited as mechanisms of child development. Researchers should be cautious when considering explanations of developmental data, since chunking may be able to explain differences in performance without the need for additional mechanisms of development.

Adult neurogenesis supports short-term olfactory memory.

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Arenkiel, Benjamin R

2010-06-01

Adult neurogenesis has captivated neuroscientists for decades, with hopes that understanding the programs underlying this phenomenon may provide unique insight toward avenues for brain repair. Interestingly, however, despite intense molecular and cellular investigation, the evolutionary roles and biological functions for ongoing neurogenesis have remained elusive. Here I review recent work published in the Journal of Neuroscience that reveals a functional role for continued neurogenesis toward forming short-term olfactory memories.

Errors in nonword repetition: bridging short- and long-term memory.

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Santos, F H; Bueno, O F A; Gathercole, S E

2006-03-01

According to the working memory model, the phonological loop is the component of working memory specialized in processing and manipulating limited amounts of speech-based information. The Children's Test of Nonword Repetition (CNRep) is a suitable measure of phonological short-term memory for English-speaking children, which was validated by the Brazilian Children's Test of Pseudoword Repetition (BCPR) as a Portuguese-language version. The objectives of the present study were: i) to investigate developmental aspects of the phonological memory processing by error analysis in the nonword repetition task, and ii) to examine phoneme (substitution, omission and addition) and order (migration) errors made in the BCPR by 180 normal Brazilian children of both sexes aged 4-10, from preschool to 4th grade. The dominant error was substitution [F(3,525) = 180.47; P long than in short items, was observed [F(3,519) = 108.36; P long-term memory contributes to holding memory trace. The findings were discussed in terms of distinctiveness, clustering and redintegration hypotheses.

Short-term incentive schemes for hospital managers

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Lucas Malambe

2013-10-01

Full Text Available Orientation: Short-term incentives, considered to be an extrinsic motivation, are commonly used to motivate performance. This study explored hospital managers’ perceptions of short term incentives in maximising performance and retention. Research purpose: The study explored the experiences, views and perceptions of private hospital managers in South Africa regarding the use of short-term incentives to maximise performance and retention, as well as the applicability of the findings to public hospitals. Motivation for the study: Whilst there is an established link between performance reward schemes and organisational performance, there is little understanding of the effects of short term incentives on the performance and retention of hospital managers within the South African context. Research design, approach, and method: The study used a qualitative research design: interviews were conducted with a purposive sample of 19 hospital managers, and a thematic content analysis was performed. Main findings: Short-term incentives may not be the primary motivator for hospital managers, but they do play a critical role in sustaining motivation. Participants indicated that these schemes could also be applicable to public hospitals. Practical/managerial implications: Hospital managers are inclined to be more motivated by intrinsic than extrinsic factors. However, hospital managers (as middle managers also seem to be motivated by short-term incentives. A combination of intrinsic and extrinsic motivators should thus be used to maximise performance and retention. Contribution/value-add: Whilst the study sought to explore hospital managers’ perceptions of short-term incentives, it also found that an adequate balance between internal and external motivators is key to implementing an effective short-term incentive scheme.

Short-Term Intercultural Psychotherapy: Ethnographic Inquiry

Science.gov (United States)

Seeley, Karen M.

2004-01-01

This article examines the challenges specific to short-term intercultural treatments and recently developed approaches to intercultural treatments based on notions of cultural knowledge and cultural competence. The article introduces alternative approaches to short-term intercultural treatments based on ethnographic inquiry adapted for clinical…

Relation between working memory and self-control capacity in participants with mild intellectual disability

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Dučić Bojan

2017-01-01

Full Text Available Working memory is activated in situations which require active control of directing attention, processing information and making it available for a short time. Its content is limited in capacity and changes with regard to the context of a performed activity. Self-control is the capacity of a voluntary conscious effort to persist in achieving a previously set goal. The aim of this research was to determine the relation of verbal and visuospatial aspects of working memory with self-control skills in persons with mild intellectual disability (ID. The sample included 40 participants 8-12 years of age (M=10.65, SD=1.19. Memorizing a Maze task, adapted for participants with ID, was used to determine the capacity of visuospatial aspect of working memory. Memorizing Animals task was used to assess verbal aspect of working memory, and Self-Control Rating Scale was used to determine the acquisition level of self-control skills. It was determined that verbal aspects of working memory were significantly related to the acquired level of self-control skills (p=0.002. There was no significant relation between the results of tasks assessing the capacity of visuospatial working memory and the success on the scale assessing self-control capacity (p=0.089. The relation between self-control and verbal aspect of working memory may be explained by close links between using speech and applying self-regulation strategies.

Why do short term workers have high mortality?

DEFF Research Database (Denmark)

Kolstad, Henrik; Olsen, Jørn

1999-01-01

or violence, the rate ratios for short term employment were 2.30 (95% Cl 1.74-3.06) and 1.86 (95% Cl 1.35-2.56), respectively. An unhealthy lifestyle may also be a determinant of short term employment. While it is possible in principle to adjust for lifestyle factors if proper data are collected, the health......Increased mortality is often reported among workers in short term employment. This may indicate either a health-related selection process or the presence of different lifestyle or social conditions among short term workers. The authors studied these two aspects of short term employment among 16...

Serial-order short-term memory predicts vocabulary development: evidence from a longitudinal study.

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Leclercq, Anne-Lise; Majerus, Steve

2010-03-01

Serial-order short-term memory (STM), as opposed to item STM, has been shown to be very consistently associated with lexical learning abilities in cross-sectional study designs. This study investigated longitudinal predictions between serial-order STM and vocabulary development. Tasks maximizing the temporary retention of either serial-order or item information were administered to kindergarten children aged 4 and 5. At age 4, age 5, and from age 4 to age 5, serial-order STM capacities, but not item STM capacities, were specifically associated with vocabulary development. Moreover, the increase of serial-order STM capacity from age 4 to age 5 predicted the increase of vocabulary knowledge over the same time period. These results support a theoretical position that assumes an important role for serial-order STM capacities in vocabulary acquisition.

Emulating short-term synaptic dynamics with memristive devices

Science.gov (United States)

Berdan, Radu; Vasilaki, Eleni; Khiat, Ali; Indiveri, Giacomo; Serb, Alexandru; Prodromakis, Themistoklis

2016-01-01

Neuromorphic architectures offer great promise for achieving computation capacities beyond conventional Von Neumann machines. The essential elements for achieving this vision are highly scalable synaptic mimics that do not undermine biological fidelity. Here we demonstrate that single solid-state TiO2 memristors can exhibit non-associative plasticity phenomena observed in biological synapses, supported by their metastable memory state transition properties. We show that, contrary to conventional uses of solid-state memory, the existence of rate-limiting volatility is a key feature for capturing short-term synaptic dynamics. We also show how the temporal dynamics of our prototypes can be exploited to implement spatio-temporal computation, demonstrating the memristors full potential for building biophysically realistic neural processing systems.

Characterizing short-term stability for Boolean networks over any distribution of transfer functions

International Nuclear Information System (INIS)

Seshadhri, C.; Smith, Andrew M.; Vorobeychik, Yevgeniy; Mayo, Jackson R.; Armstrong, Robert C.

2016-01-01

Here we present a characterization of short-term stability of random Boolean networks under arbitrary distributions of transfer functions. Given any distribution of transfer functions for a random Boolean network, we present a formula that decides whether short-term chaos (damage spreading) will happen. We provide a formal proof for this formula, and empirically show that its predictions are accurate. Previous work only works for special cases of balanced families. Finally, it has been observed that these characterizations fail for unbalanced families, yet such families are widespread in real biological networks.

Capacity for work researching method in animal experiment

International Nuclear Information System (INIS)

Pul'nov, V.N.; Mashneva, N.I.

1978-01-01

The existing methods of examining the work capacity of animals are discussed with reference to extrapolation of animal data to man. A modified procedure for measuring maximal physical strength is proposed, whereby static endurance of animals at a given exercise rate can be measured. For an integrated evaluation of work capacity, a formula of absolute work capacity is suggested. The proposed procedure may be used to study the working capacity of animals exposed to unfavorable factors of radiation or nonradiation nature

Non Temporal Determinants of Bilingual Memory Capacity: The Role of Long-Term Representations and Fluency.

Science.gov (United States)

Chincotta, Dino; Underwood, Geoffrey

1998-01-01

Examined the view that the variation in bilingual short-term memory capacity is determined by differential rates of subvocal rehearsal between the languages. Auditory memory span and articulation time were measured for three bilingual groups who spoke Finnish at home and Swedish at school, and either Finnish of Swedish in both the home and the…

Short-term mechanisms influencing volumetric brain dynamics

Directory of Open Access Journals (Sweden)

Nikki Dieleman

2017-01-01

Full Text Available With the use of magnetic resonance imaging (MRI and brain analysis tools, it has become possible to measure brain volume changes up to around 0.5%. Besides long-term brain changes caused by atrophy in aging or neurodegenerative disease, short-term mechanisms that influence brain volume may exist. When we focus on short-term changes of the brain, changes may be either physiological or pathological. As such determining the cause of volumetric dynamics of the brain is essential. Additionally for an accurate interpretation of longitudinal brain volume measures by means of neurodegeneration, knowledge about the short-term changes is needed. Therefore, in this review, we discuss the possible mechanisms influencing brain volumes on a short-term basis and set-out a framework of MRI techniques to be used for volumetric changes as well as the used analysis tools. 3D T1-weighted images are the images of choice when it comes to MRI of brain volume. These images are excellent to determine brain volume and can be used together with an analysis tool to determine the degree of volume change. Mechanisms that decrease global brain volume are: fluid restriction, evening MRI measurements, corticosteroids, antipsychotics and short-term effects of pathological processes like Alzheimer's disease, hypertension and Diabetes mellitus type II. Mechanisms increasing the brain volume include fluid intake, morning MRI measurements, surgical revascularization and probably medications like anti-inflammatory drugs and anti-hypertensive medication. Exercise was found to have no effect on brain volume on a short-term basis, which may imply that dehydration caused by exercise differs from dehydration by fluid restriction. In the upcoming years, attention should be directed towards studies investigating physiological short-term changes within the light of long-term pathological changes. Ultimately this may lead to a better understanding of the physiological short-term effects of

Real-time energy resources scheduling considering short-term and very short-term wind forecast

Energy Technology Data Exchange (ETDEWEB)

Silva, Marco; Sousa, Tiago; Morais, Hugo; Vale, Zita [Polytechnic of Porto (Portugal). GECAD - Knowledge Engineering and Decision Support Research Center

2012-07-01

This paper proposes an energy resources management methodology based on three distinct time horizons: day-ahead scheduling, hour-ahead scheduling, and real-time scheduling. In each scheduling process the update of generation and consumption operation and of the storage and electric vehicles storage status are used. Besides the new operation conditions, the most accurate forecast values of wind generation and of consumption using results of short-term and very short-term methods are used. A case study considering a distribution network with intensive use of distributed generation and electric vehicles is presented. (orig.)

The Mind and Brain of Short-Term Memory

OpenAIRE

Jonides, John; Lewis, Richard L.; Nee, Derek Evan; Lustig, Cindy A.; Berman, Marc G.; Moore, Katherine Sledge

2008-01-01

The past 10 years have brought near-revolutionary changes in psychological theories about short-term memory, with similarly great advances in the neurosciences. Here, we critically examine the major psychological theories (the “mind”) of short-term memory and how they relate to evidence about underlying brain mechanisms. We focus on three features that must be addressed by any satisfactory theory of short-term memory. First, we examine the evidence for the architecture of short-term memory, w...

Very-long-term and short-term chromatic adaptation: are their influences cumulative?

Science.gov (United States)

Belmore, Suzanne C; Shevell, Steven K

2011-02-09

Very-long-term (VLT) chromatic adaptation results from exposure to an altered chromatic environment for days or weeks. Color shifts from VLT adaptation are observed hours or days after leaving the altered environment. Short-term chromatic adaptation, on the other hand, results from exposure for a few minutes or less, with color shifts measured within seconds or a few minutes after the adapting light is extinguished; recovery to the pre-adapted state is complete in less than an hour. Here, both types of adaptation were combined. All adaptation was to reddish-appearing long-wavelength light. Shifts in unique yellow were measured following adaptation. Previous studies demonstrate shifts in unique yellow due to VLT chromatic adaptation, but shifts from short-term chromatic adaptation to comparable adapting light can be far greater than from VLT adaptation. The question considered here is whether the color shifts from VLT adaptation are cumulative with large shifts from short-term adaptation or, alternatively, does simultaneous short-term adaptation eliminate color shifts caused by VLT adaptation. The results show the color shifts from VLT and short-term adaptation together are cumulative, which indicates that both short-term and very-long-term chromatic adaptation affect color perception during natural viewing. Copyright © 2010 Elsevier Ltd. All rights reserved.

On the Option Effects of Short-Time Work Arrangements

NARCIS (Netherlands)

Huisman, Kuno; Thijssen, J.J.J.

2018-01-01

We analyse the short term work (STW) regulations that several OECD countries introduced after the 2007 financial crisis. We view these measures as a collection of real options and study the dynamic effect of STW on the endogenous liquidation decision of the firm. While STW delays a firm’s

Visual Working Memory Capacity and Proactive Interference

OpenAIRE

Hartshorne, Joshua

2008-01-01

BACKGROUND: Visual working memory capacity is extremely limited and appears to be relatively immune to practice effects or the use of explicit strategies. The recent discovery that visual working memory tasks, like verbal working memory tasks, are subject to proactive interference, coupled with the fact that typical visual working memory tasks are particularly conducive to proactive interference, suggests that visual working memory capacity may be systematically under-estimated. METHODOLOGY/P...

Statistical mechanics of neocortical interactions: Constraints on 40-Hz models of short-term memory

Science.gov (United States)

Ingber, Lester

1995-10-01

Calculations presented in L. Ingber and P.L. Nunez, Phys. Rev. E 51, 5074 (1995) detailed the evolution of short-term memory in the neocortex, supporting the empirical 7+/-2 rule of constraints on the capacity of neocortical processing. These results are given further support when other recent models of 40-Hz subcycles of low-frequency oscillations are considered.

Fundamental bound on the persistence and capacity of short-term memory stored as graded persistent activity.

Science.gov (United States)

Koyluoglu, Onur Ozan; Pertzov, Yoni; Manohar, Sanjay; Husain, Masud; Fiete, Ila R

2017-09-07

It is widely believed that persistent neural activity underlies short-term memory. Yet, as we show, the degradation of information stored directly in such networks behaves differently from human short-term memory performance. We build a more general framework where memory is viewed as a problem of passing information through noisy channels whose degradation characteristics resemble those of persistent activity networks. If the brain first encoded the information appropriately before passing the information into such networks, the information can be stored substantially more faithfully. Within this framework, we derive a fundamental lower-bound on recall precision, which declines with storage duration and number of stored items. We show that human performance, though inconsistent with models involving direct (uncoded) storage in persistent activity networks, can be well-fit by the theoretical bound. This finding is consistent with the view that if the brain stores information in patterns of persistent activity, it might use codes that minimize the effects of noise, motivating the search for such codes in the brain.

Access to long-term capacity for electric interconnections: towards a single European set of rules

International Nuclear Information System (INIS)

2010-05-01

Guaranteeing firmness of interconnection capacity (or compensating curtailments based on the daily market prices) is a key element to the design of the integrated European electricity market. However, although the European energy regulators are on the way to reaching a consensus on the target to be met in terms of firmness, there is less consensus on how this target can be reached, which means the two following key questions will have to be duly addressed: - How can we improve confidence in the daily price references used to compensate interconnection capacity holders in cases of curtailment? - How can we encourage transmission system operators to allocate a maximum of financially firm capacity, at a lesser cost for network users? In the short-term, in the absence of appropriate incentive mechanisms to maximise capacity, the regulators have no other choice but to guarantee transmission system operators that costs related to firmness of capacity allocated at the different time frames will be covered. In this perspective, transitory solutions can be implemented by regulators in order to limit the risk borne by network users (for example, by introducing caps on price differentials and/or on the budget available for compensating curtailments). The choices in terms of capacity and how it is distributed between the different time frames (daily, monthly, annual and multi-annual) are also important decision variables, as these could limit the risk borne by network users. In such, as they are responsible for guaranteeing the interests of network users, the regulators should decide what level of capacity should be made available to the market. This decision should be taken in close collaboration with the network operators, who have all the expertise needed in terms of calculating capacity. Finally, on the interconnections where a market-coupling mechanism exists, the regulators should ask the transmission system operators to allocate the long-term interconnection capacity in

Investigating domain-general short-term memory for order versus specific item memory in developmental dyslexia

OpenAIRE

Hachmann, Wibke Maria

2012-01-01

Recent findings suggest that people with dyslexia experience difficulties with the learning of serial order information during the transition from short- to long-term memory. At the same time, models of short-term memory increasingly incorporate a distinction of order and item processing. This work aims to investigate whether serial order processing deficiencies in dyslexia can be traced back to a selective impairment of short-term memory for serial order, and whether this impairment also aff...

Working Memory Capacity, Confidence and Scientific Thinking

Science.gov (United States)

Al-Ahmadi, Fatheya; Oraif, Fatima

2009-01-01

Working memory capacity is now well established as a rate determining factor in much learning and assessment, especially in the sciences. Most of the research has focussed on performance in tests and examinations in subject areas. This paper outlines some exploratory work in which other outcomes are related to working memory capacity. Confidence…

Estimating the net benefit of a specialized return-to-work program for workers on short-term disability related to a mental disorder: an example exploring investment in collaborative care.

Science.gov (United States)

Dewa, Carolyn S; Hoch, Jeffrey S

2014-06-01

This article estimates the net benefit for a company incorporating a collaborative care model into its return-to-work program for workers on short-term disability related to a mental disorder. Employing a simple decision model, the net benefit and uncertainty were explored. The breakeven point occurs when the average short-term disability episode is reduced by at least 7 days. In addition, 85% of the time, benefits could outweigh costs. Model results and sensitivity analyses indicate that organizational benefits can be greater than the costs of incorporating a collaborative care model into a return-to-work program for workers on short-term disability related to a mental disorder. The results also demonstrate how the probability of a program's effectiveness and the magnitude of its effectiveness are key factors that determine whether the benefits of a program outweigh its costs.

Short-term natural gas consumption forecasting

International Nuclear Information System (INIS)

Potocnik, P.; Govekar, E.; Grabec, I.

2007-01-01

Energy forecasting requirements for Slovenia's natural gas market were investigated along with the cycles of natural gas consumption. This paper presented a short-term natural gas forecasting approach where the daily, weekly and yearly gas consumption were analyzed and the information obtained was incorporated into the forecasting model for hourly forecasting for the next day. The natural gas market depends on forecasting in order to optimize the leasing of storage capacities. As such, natural gas distribution companies have an economic incentive to accurately forecast their future gas consumption. The authors proposed a forecasting model with the following properties: two submodels for the winter and summer seasons; input variables including past consumption data, weather data, weather forecasts and basic cycle indexes; and, a hierarchical forecasting structure in which a daily model was used as the basis, with the hourly forecast obtained by modeling the relative daily profile. This proposed method was illustrated by a forecasting example for Slovenia's natural gas market. 11 refs., 11 figs

What's Magic about Magic Numbers? Chunking and Data Compression in Short-Term Memory

Science.gov (United States)

Mathy, Fabien; Feldman, Jacob

2012-01-01

Short term memory is famously limited in capacity to Miller's (1956) magic number 7 plus or minus 2--or, in many more recent studies, about 4 plus or minus 1 "chunks" of information. But the definition of "chunk" in this context has never been clear, referring only to a set of items that are treated collectively as a single unit. We propose a new…

Short-term energy outlook, quarterly projections, second quarter 1998

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-04-01

The Energy Information Administration (EIA) prepares quarterly short-term energy supply, demand, and price projections. The details of these projections, as well as monthly updates, are available on the Internet at: www.eia.doe.gov/emeu/steo/pub/contents.html. The paper discusses outlook assumptions; US energy prices; world oil supply and the oil production cutback agreement of March 1998; international oil demand and supply; world oil stocks, capacity, and net trade; US oil demand and supply; US natural gas demand and supply; US coal demand and supply; US electricity demand and supply; US renewable energy demand; and US energy demand and supply sensitivities. 29 figs., 19 tabs.

Estimation of work capacity and work ability among plantation workers in South India

OpenAIRE

Anbazhagan, Suguna; Ramesh, Naveen; Surekha, A; Fathima, Farah N.; Melina,; Anjali,

2016-01-01

Background: Work capacity is the ability to perform real physical work, and work ability is a result of interaction of worker to his or her work that is how good a worker is at present, in near future, and how able is he or she to do his or her work with respect to work demands and health and mental resources. Objective: To assess the work capacity and work ability and to study the factors associated with work capacity and work ability of workers at a tea plantation in South India. Materials ...

Attending to unrelated targets boosts short-term memory for color arrays.

Science.gov (United States)

Makovski, Tal; Swallow, Khena M; Jiang, Yuhong V

2011-05-01

Detecting a target typically impairs performance in a second, unrelated task. It has been recently reported however, that detecting a target in a stream of distractors can enhance long-term memory of faces and scenes that were presented concurrently with the target (the attentional boost effect). In this study we ask whether target detection also enhances performance in a visual short-term memory task, where capacity limits are severe. Participants performed two tasks at once: a one shot, color change detection task and a letter-detection task. In Experiment 1, a central letter appeared at the same time as 3 or 5 color patches (memory display). Participants encoded the colors and pressed the spacebar if the letter was a T (target). After a short retention interval, a probe display of color patches appeared. Performance on the change detection task was enhanced when a target, rather than a distractor, appeared with the memory display. This effect was not modulated by memory load or the frequency of trials in which a target appeared. However, there was no enhancement when the target appeared at the same time as the probe display (Experiment 2a) or during the memory retention interval (Experiment 2b). Together these results suggest that detecting a target facilitates the encoding of unrelated information into visual short-term memory. Copyright © 2010 Elsevier Ltd. All rights reserved.

Estimation of work capacity and work ability among plantation workers in South India.

Science.gov (United States)

Anbazhagan, Suguna; Ramesh, Naveen; Surekha, A; Fathima, Farah N; Melina; Anjali

2016-01-01

Work capacity is the ability to perform real physical work, and work ability is a result of interaction of worker to his or her work that is how good a worker is at present, in near future, and how able is he or she to do his or her work with respect to work demands and health and mental resources. To assess the work capacity and work ability and to study the factors associated with work capacity and work ability of workers at a tea plantation in South India. A cross-sectional study was conducted at a tea plantation in Annamalai, South India, from March to May 2015. Data were collected using a structured interview schedule comprising of three parts as follows: sociodemographic data, work ability questionnaire, and work capacity assessment. Of the 199 subjects participated in the study, majority [90 (45.3%)] were in the age group of 46-55 years, and 128 (64.3%) were females. Of the 199 workers, 12.6% had poor aerobic capacity (by Harvard Step test), 88.4% had an endurance of more than 1 h, 70.9% had better work productivity and energetic efficiency, and the voluntary activity workers spent most time on household chores. Of the 199 workers assessed, only 9.6% had good work ability. There is negative correlation between work ability and body mass index (BMI). Our study found 12.6% workers with poor aerobic capacity and 9.6% of workers with good work ability. Periodic health examinations and other screening procedures should be made as routine in workplace to improve work ability and capacity.

Recombinant growth differentiation factor 11 influences short-term memory and enhances Sox2 expression in middle-aged mice.

Science.gov (United States)

Zhang, Min; Jadavji, Nafisa M; Yoo, Hyung-Suk; Smith, Patrice D

2018-04-02

Previous evidence suggests that a significant decline in cognitive ability begins during middle-age and continues to deteriorate with increase in age. Recent work has demonstrated the potential rejuvenation impact of growth differentiation factor-11 (GDF-11) in aged mice. We carried out experiments to evaluate the impact of a single dose of recombinant (rGDF-11) on short-term visual and spatial memory in middle-aged male mice. On the novel object recognition task, we observed middle-aged mice treated rGDF-11 showed improved performance on the novel object recognition task. However, middle-aged mice did not show increased expression of phosphorylated-Smad2/3, a downstream effector of GDF-11. We noted however that the expression of the transcription factor, Sox2 was increased within the dentate gyrus. Our data suggest that a single injection of rGDF-11 contributes to improvements in cognitive function of middle-aged animals, which may be critical in the preservation of short-term memory capacity in old age. Copyright © 2017 Elsevier B.V. All rights reserved.

No effect of transcranial direct current stimulation of the dorsolateral prefrontal cortex on short-term memory.

Science.gov (United States)

Wang, Jing; Wen, Jian-Bing; Li, Xiao-Li

2018-01-01

Short-term memory refers to the capacity for holding information in mind for a short period of time with conscious memorization. It is an important ability for daily life and is impaired in several neurological and psychiatric disorders. Anodal transcranial direct current stimulation (tDCS) applied to the dorsolateral prefrontal cortex (DLPFC) was reported to enhance the capability of short-term memory in healthy subjects. However, results were not consistent and what is the possible impact factor is not known. One important factor that may significantly influence the effect of tDCS is the timing of tDCS administration. In order to explore whether tDCS impact short-term memory and the optimal timing of tDCS administration, we applied anodal tDCS to the left DLPFC to explore the modulatory effect of online and off-line tDCS on digit span as well as visual short-term memory performance in healthy subjects. Results showed tDCS of the left DLPFC did not influence intentional digit span memory performance, whether before the task or during the task. In addition, tDCS of the DLPFC administered before the task showed no effect on visual short-term memory, while there was a trend of increase in false alarm when tDCS of the DLPFC administered during the task. These results did not provide evidence for the enhancement of short-term memory by tDCS of the left DLPFC in healthy subjects, but it suggested an importance of administration time for visual short-term memory. Further studies are required to taking into account the baseline performance of subjects and time-dependence feature of tDCS. © 2017 John Wiley & Sons Ltd.

Short-term indicators. Intensities as a proxy for savings

Energy Technology Data Exchange (ETDEWEB)

Boonekamp, P.G.M.; Gerdes, J. [ECN Policy Studies, Petten (Netherlands); Faberi, S. [Institute of Studies for the Integration of Systems ISIS, Rome (Italy)

2013-12-15

The ODYSSEE database on energy efficiency indicators (www.odyssee-indicators.org) has been set up to enable the monitoring and evaluation of realised energy efficiency improvements and related energy savings. The database covers the 27 EU countries as well as Norway and Croatia and data are available from 1990 on. This work contributes to the growing need for quantitative monitoring and evaluation of the impacts of energy policies and measures, both at the EU and national level, e.g. due to the Energy Services Directive and the proposed Energy Efficiency Directive. Because the underlying data become available only after some time, the savings figures are not always timely available. This is especially true for the ODEX efficiency indices per sector that rely on a number of indicators. Therefore, there is a need for so-called short-term indicators that become available shortly after the year has passed for which data are needed. The short term indicators do not replace the savings indicators but function as a proxy for the savings in the most recent year. This proxy value is faster available, but will be less accurate than the saving indicators themselves. The short term indicators have to be checked regularly with the ODEX indicators in order to see whether they can function still as a proxy.

Working memory training may increase working memory capacity but not fluid intelligence.

Science.gov (United States)

Harrison, Tyler L; Shipstead, Zach; Hicks, Kenny L; Hambrick, David Z; Redick, Thomas S; Engle, Randall W

2013-12-01

Working memory is a critical element of complex cognition, particularly under conditions of distraction and interference. Measures of working memory capacity correlate positively with many measures of real-world cognition, including fluid intelligence. There have been numerous attempts to use training procedures to increase working memory capacity and thereby performance on the real-world tasks that rely on working memory capacity. In the study reported here, we demonstrated that training on complex working memory span tasks leads to improvement on similar tasks with different materials but that such training does not generalize to measures of fluid intelligence.

Short term and medium term power distribution load forecasting by neural networks

International Nuclear Information System (INIS)

Yalcinoz, T.; Eminoglu, U.

2005-01-01

Load forecasting is an important subject for power distribution systems and has been studied from different points of view. In general, load forecasts should be performed over a broad spectrum of time intervals, which could be classified into short term, medium term and long term forecasts. Several research groups have proposed various techniques for either short term load forecasting or medium term load forecasting or long term load forecasting. This paper presents a neural network (NN) model for short term peak load forecasting, short term total load forecasting and medium term monthly load forecasting in power distribution systems. The NN is used to learn the relationships among past, current and future temperatures and loads. The neural network was trained to recognize the peak load of the day, total load of the day and monthly electricity consumption. The suitability of the proposed approach is illustrated through an application to real load shapes from the Turkish Electricity Distribution Corporation (TEDAS) in Nigde. The data represents the daily and monthly electricity consumption in Nigde, Turkey

Working memory capacity as a dynamic process

Directory of Open Access Journals (Sweden)

Vanessa R Simmering

2013-01-01

Full Text Available A well-known characteristic of working memory is its limited capacity. The source of such limitations, however, is a continued point of debate. Developmental research is positioned to address this debate by jointly identifying the source(s of limitations and the mechanism(s underlying capacity increases. Here we provide a cross-domain survey of studies and theories of working memory capacity development, which reveals a complex picture: dozens of studies from 50 papers show nearly universal increases in capacity estimates with age, but marked variation across studies, tasks, and domains. We argue that the full pattern of performance cannot be captured through traditional approaches emphasizing single causes, or even multiple separable causes, underlying capacity development. Rather, we consider working memory capacity as a dynamic process that emerges from a unified cognitive system flexibly adapting to the context and demands of each task. We conclude by enumerating specific challenges for researchers and theorists that will need to be met in order to move our understanding forward.

Short-term memory, executive control, and children's route learning

OpenAIRE

Purser, H. R.; Farran, E. K.; Courbois, Y.; Lemahieu, A.; Mellier, D.; Sockeel, P.; Blades, M.

2012-01-01

The aim of this study was to investigate route-learning ability in 67 children aged 5 to 11years and to relate route-learning performance to the components of Baddeley's model of working memory. Children carried out tasks that included measures of verbal and visuospatial short-term memory and executive control and also measures of verbal and visuospatial long-term memory; the route-learning task was conducted using a maze in a virtual environment. In contrast to previous research, correlation...

Swarm Intelligence-Based Hybrid Models for Short-Term Power Load Prediction

Directory of Open Access Journals (Sweden)

Jianzhou Wang

2014-01-01

Full Text Available Swarm intelligence (SI is widely and successfully applied in the engineering field to solve practical optimization problems because various hybrid models, which are based on the SI algorithm and statistical models, are developed to further improve the predictive abilities. In this paper, hybrid intelligent forecasting models based on the cuckoo search (CS as well as the singular spectrum analysis (SSA, time series, and machine learning methods are proposed to conduct short-term power load prediction. The forecasting performance of the proposed models is augmented by a rolling multistep strategy over the prediction horizon. The test results are representative of the out-performance of the SSA and CS in tuning the seasonal autoregressive integrated moving average (SARIMA and support vector regression (SVR in improving load forecasting, which indicates that both the SSA-based data denoising and SI-based intelligent optimization strategy can effectively improve the model’s predictive performance. Additionally, the proposed CS-SSA-SARIMA and CS-SSA-SVR models provide very impressive forecasting results, demonstrating their strong robustness and universal forecasting capacities in terms of short-term power load prediction 24 hours in advance.

Short-Term Memory, Executive Control, and Children's Route Learning

Science.gov (United States)

Purser, Harry R. M.; Farran, Emily K.; Courbois, Yannick; Lemahieu, Axelle; Mellier, Daniel; Sockeel, Pascal; Blades, Mark

2012-01-01

The aim of this study was to investigate route-learning ability in 67 children aged 5 to 11 years and to relate route-learning performance to the components of Baddeley's model of working memory. Children carried out tasks that included measures of verbal and visuospatial short-term memory and executive control and also measures of verbal and…

The Effect of Perceptual Expertise on Visual Short-Term Memory

Directory of Open Access Journals (Sweden)

Wei Zhang

2011-05-01

Full Text Available Visual working memory (VWM capacity is larger for faces than other complex objects. Inversion reduces capacity for faces more than nonfaces (Curby and Gauthier, 2007. These findings suggest that VWM is influenced by the encoding processes employed by face experts. Scolari, Vogel and Awh (2008 found that perceptual expertise enables a more detailed memory, instead of a larger WM capacity, for faces than nonfaces. Since people are more expert at recognizing own-race than other-race faces, we investigated whether this advantage is due to a higher resolution of own-race face representations. Six study items (Chinese and Caucasian faces, shaded cubes were simultaneously shown on screen on each trial. After a short delay, a single image was presented. Participants were asked to judge whether this image was the same or different from the item that originally appeared in that location. Neither own-race nor other-race faces showed an inversion effect when stimuli changed between categories (face to cube, cube to face. However, an inversion effect was found for both own-race and other-race faces when changes occurred within a category (face to face, cube to cube. These results suggest that both own-race and other-race faces are stored with high resolution in working memory.

Adolescent Development of Global Competencies through a Short-Term International Study-Travel Experience to China

Science.gov (United States)

Gould, Rachel Zucker

2012-01-01

The capacity of adolescents to develop global competencies was examined by collecting and analyzing data from 62 student-travelers before, during, and after a short-term study-travel experience to China. The Global Perspectives Inventory was used to compare the student-travelers' perspectives before and after travel with a comparison group of 60…

An adaptive short-term prediction scheme for wind energy storage management

International Nuclear Information System (INIS)

Blonbou, Ruddy; Monjoly, Stephanie; Dorville, Jean-Francois

2011-01-01

Research highlights: → We develop a real time algorithm for grid-connected wind energy storage management. → The method aims to guarantee, with ±5% error margin, the power sent to the grid. → Dynamic scheduling of energy storage is based on short-term energy prediction. → Accurate predictions reduce the need in storage capacity. -- Abstract: Efficient forecasting scheme that includes some information on the likelihood of the forecast and based on a better knowledge of the wind variations characteristics along with their influence on power output variation is of key importance for the optimal integration of wind energy in island's power system. In the Guadeloupean archipelago (French West-Indies), with a total wind power capacity of 25 MW; wind energy can represent up to 5% of the instantaneous electricity production. At this level, wind energy contribution can be equivalent to the current network primary control reserve, which causes balancing difficult. The share of wind energy is due to grow even further since the objective is set to reach 118 MW by 2020. It is an absolute evidence for the network operator that due to security concerns of the electrical grid, the share of wind generation should not increase unless solutions are found to solve the prediction problem. The University of French West-Indies and Guyana has developed a short-term wind energy prediction scheme that uses artificial neural networks and adaptive learning procedures based on Bayesian approach and Gaussian approximation. This paper reports the results of the evaluation of the proposed approach; the improvement with respect to the simple persistent prediction model was globally good. A discussion on how such a tool combined with energy storage capacity could help to smooth the wind power variation and improve the wind energy penetration rate into island utility network is also proposed.

Short-Term Memory and Aphasia: From Theory to Treatment.

Science.gov (United States)

Minkina, Irene; Rosenberg, Samantha; Kalinyak-Fliszar, Michelene; Martin, Nadine

2017-02-01

This article reviews existing research on the interactions between verbal short-term memory and language processing impairments in aphasia. Theoretical models of short-term memory are reviewed, starting with a model assuming a separation between short-term memory and language, and progressing to models that view verbal short-term memory as a cognitive requirement of language processing. The review highlights a verbal short-term memory model derived from an interactive activation model of word retrieval. This model holds that verbal short-term memory encompasses the temporary activation of linguistic knowledge (e.g., semantic, lexical, and phonological features) during language production and comprehension tasks. Empirical evidence supporting this model, which views short-term memory in the context of the processes it subserves, is outlined. Studies that use a classic measure of verbal short-term memory (i.e., number of words/digits correctly recalled in immediate serial recall) as well as those that use more intricate measures (e.g., serial position effects in immediate serial recall) are discussed. Treatment research that uses verbal short-term memory tasks in an attempt to improve language processing is then summarized, with a particular focus on word retrieval. A discussion of the limitations of current research and possible future directions concludes the review. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

High visual working memory capacity in trait social anxiety.

Science.gov (United States)

Moriya, Jun; Sugiura, Yoshinori

2012-01-01

Working memory capacity is one of the most important cognitive functions influencing individual traits, such as attentional control, fluid intelligence, and also psychopathological traits. Previous research suggests that anxiety is associated with impaired cognitive function, and studies have shown low verbal working memory capacity in individuals with high trait anxiety. However, the relationship between trait anxiety and visual working memory capacity is still unclear. Considering that people allocate visual attention more widely to detect danger under threat, visual working memory capacity might be higher in anxious people. In the present study, we show that visual working memory capacity increases as trait social anxiety increases by using a change detection task. When the demand to inhibit distractors increased, however, high visual working memory capacity diminished in individuals with social anxiety, and instead, impaired filtering of distractors was predicted by trait social anxiety. State anxiety was not correlated with visual working memory capacity. These results indicate that socially anxious people could potentially hold a large amount of information in working memory. However, because of an impaired cognitive function, they could not inhibit goal-irrelevant distractors and their performance decreased under highly demanding conditions.

Saturation of auditory short-term memory causes a plateau in the sustained anterior negativity event-related potential.

Science.gov (United States)

Alunni-Menichini, Kristelle; Guimond, Synthia; Bermudez, Patrick; Nolden, Sophie; Lefebvre, Christine; Jolicoeur, Pierre

2014-12-10

The maintenance of information in auditory short-term memory (ASTM) is accompanied by a sustained anterior negativity (SAN) in the event-related potential measured during the retention interval of simple auditory memory tasks. Previous work on ASTM showed that the amplitude of the SAN increased in negativity as the number of maintained items increases. The aim of the current study was to measure the SAN and observe its behavior beyond the point of saturation of auditory short-term memory. We used atonal pure tones in sequences of 2, 4, 6, or 8t. Our results showed that the amplitude of SAN increased in negativity from 2 to 4 items and then levelled off from 4 to 8 items. Behavioral results suggested that the average span in the task was slightly below 3, which was consistent with the observed plateau in the electrophysiological results. Furthermore, the amplitude of the SAN predicted individual differences in auditory memory capacity. The results support the hypothesis that the SAN is an electrophysiological index of brain activity specifically related to the maintenance of auditory information in ASTM. Copyright © 2014 Elsevier B.V. All rights reserved.

A fuzzy inference model for short-term load forecasting

International Nuclear Information System (INIS)

Mamlook, Rustum; Badran, Omar; Abdulhadi, Emad

2009-01-01

This paper is concerned with the short-term load forecasting (STLF) in power system operations. It provides load prediction for generation scheduling and unit commitment decisions, and therefore precise load forecasting plays an important role in reducing the generation cost and the spinning reserve capacity. Short-term electricity demand forecasting (i.e., the prediction of hourly loads (demand)) is one of the most important tools by which an electric utility/company plans, dispatches the loading of generating units in order to meet system demand. The accuracy of the dispatching system, which is derived from the accuracy of the forecasting algorithm used, will determine the economics of the operation of the power system. The inaccuracy or large error in the forecast simply means that load matching is not optimized and consequently the generation and transmission systems are not being operated in an efficient manner. In the present study, a proposed methodology has been introduced to decrease the forecasted error and the processing time by using fuzzy logic controller on an hourly base. Therefore, it predicts the effect of different conditional parameters (i.e., weather, time, historical data, and random disturbances) on load forecasting in terms of fuzzy sets during the generation process. These parameters are chosen with respect to their priority and importance. The forecasted values obtained by fuzzy method were compared with the conventionally forecasted ones. The results showed that the STLF of the fuzzy implementation have more accuracy and better outcomes

Short-term treatment with flumazenil restores long-term object memory in a mouse model of Down syndrome.

Science.gov (United States)

Colas, Damien; Chuluun, Bayarsaikhan; Garner, Craig C; Heller, H Craig

2017-04-01

Down syndrome (DS) is a common genetic cause of intellectual disability yet no pro-cognitive drug therapies are approved for human use. Mechanistic studies in a mouse model of DS (Ts65Dn mice) demonstrate that impaired cognitive function is due to excessive neuronal inhibitory tone. These deficits are normalized by chronic, short-term low doses of GABA A receptor (GABA A R) antagonists in adult animals, but none of the compounds investigated are approved for human use. We explored the therapeutic potential of flumazenil (FLUM), a GABA A R antagonist working at the benzodiazepine binding site that has FDA approval. Long-term memory was assessed by the Novel Object Recognition (NOR) testing in Ts65Dn mice after acute or short-term chronic treatment with FLUM. Short-term, low, chronic dose regimens of FLUM elicit long-lasting (>1week) normalization of cognitive function in both young and aged mice. FLUM at low dosages produces long lasting cognitive improvements and has the potential of fulfilling an unmet therapeutic need in DS. Copyright © 2017. Published by Elsevier Inc.

Short-term memories with a stochastic perturbation

International Nuclear Information System (INIS)

Pontes, Jose C.A. de; Batista, Antonio M.; Viana, Ricardo L.; Lopes, Sergio R.

2005-01-01

We investigate short-term memories in linear and weakly nonlinear coupled map lattices with a periodic external input. We use locally coupled maps to present numerical results about short-term memory formation adding a stochastic perturbation in the maps and in the external input

V4 activity predicts the strength of visual short-term memory representations.

Science.gov (United States)

Sligte, Ilja G; Scholte, H Steven; Lamme, Victor A F

2009-06-10

Recent studies have shown the existence of a form of visual memory that lies intermediate of iconic memory and visual short-term memory (VSTM), in terms of both capacity (up to 15 items) and the duration of the memory trace (up to 4 s). Because new visual objects readily overwrite this intermediate visual store, we believe that it reflects a weak form of VSTM with high capacity that exists alongside a strong but capacity-limited form of VSTM. In the present study, we isolated brain activity related to weak and strong VSTM representations using functional magnetic resonance imaging. We found that activity in visual cortical area V4 predicted the strength of VSTM representations; activity was low when there was no VSTM, medium when there was a weak VSTM representation regardless of whether this weak representation was available for report or not, and high when there was a strong VSTM representation. Altogether, this study suggests that the high capacity yet weak VSTM store is represented in visual parts of the brain. Allegedly, only some of these VSTM traces are amplified by parietal and frontal regions and as a consequence reside in traditional or strong VSTM. The additional weak VSTM representations remain available for conscious access and report when attention is redirected to them yet are overwritten as soon as new visual stimuli hit the eyes.

Detailed sensory memory, sloppy working memory

NARCIS (Netherlands)

Sligte, I.G.; Vandenbroucke, A.R.E.; Scholte, H.S.; Lamme, V.A.F.

2010-01-01

Visual short-term memory (VSTM) enables us to actively maintain information in mind for a brief period of time after stimulus disappearance. According to recent studies, VSTM consists of three stages - iconic memory, fragile VSTM, and visual working memory - with increasingly stricter capacity

Investigating Executive Working Memory and Phonological Short-Term Memory in Relation to Fluency and Self-Repair Behavior in L2 Speech.

Science.gov (United States)

Georgiadou, Effrosyni; Roehr-Brackin, Karen

2017-08-01

This paper reports the findings of a study investigating the relationship of executive working memory (WM) and phonological short-term memory (PSTM) to fluency and self-repair behavior during an unrehearsed oral task performed by second language (L2) speakers of English at two levels of proficiency, elementary and lower intermediate. Correlational analyses revealed a negative relationship between executive WM and number of pauses in the lower intermediate L2 speakers. However, no reliable association was found in our sample between executive WM or PSTM and self-repair behavior in terms of either frequency or type of self-repair. Taken together, our findings suggest that while executive WM may enhance performance at the conceptualization and formulation stages of the speech production process, self-repair behavior in L2 speakers may depend on factors other than working memory.

Competitive short-term and long-term memory processes in spatial habituation.

Science.gov (United States)

Sanderson, David J; Bannerman, David M

2011-04-01

Exposure to a spatial location leads to habituation of exploration such that, in a novelty preference test, rodents subsequently prefer exploring a novel location to the familiar location. According to Wagner's (1981) theory of memory, short-term and long-term habituation are caused by separate and sometimes opponent processes. In the present study, this dual-process account of memory was tested. Mice received a series of exposure training trials to a location before receiving a novelty preference test. The novelty preference was greater when tested after a short, rather than a long, interval. In contrast, the novelty preference was weaker when exposure training trials were separated by a short, rather than a long interval. Furthermore, it was found that long-term habituation was determined by the independent effects of the amount of exposure training and the number of exposure training trials when factors such as the intertrial interval and the cumulative intertrial interval were controlled. A final experiment demonstrated that a long-term reduction of exploration could be caused by a negative priming effect due to associations formed during exploration. These results provide evidence against a single-process account of habituation and suggest that spatial habituation is determined by both short-term, recency-based memory and long-term, incrementally strengthened memory.

Retrieval-Induced Inhibition in Short-Term Memory.

Science.gov (United States)

Kang, Min-Suk; Choi, Joongrul

2015-07-01

We used a visual illusion called motion repulsion as a model system for investigating competition between two mental representations. Subjects were asked to remember two random-dot-motion displays presented in sequence and then to report the motion directions for each. Remembered motion directions were shifted away from the actual motion directions, an effect similar to the motion repulsion observed during perception. More important, the item retrieved second showed greater repulsion than the item retrieved first. This suggests that earlier retrieval exerted greater inhibition on the other item being held in short-term memory. This retrieval-induced motion repulsion could be explained neither by reduced cognitive resources for maintaining short-term memory nor by continued inhibition between short-term memory representations. These results indicate that retrieval of memory representations inhibits other representations in short-term memory. We discuss mechanisms of retrieval-induced inhibition and their implications for the structure of memory. © The Author(s) 2015.

Consequence of preterm birth in early adolescence: the role of language on auditory short-term memory.

Science.gov (United States)

Fraello, David; Maller-Kesselman, Jill; Vohr, Betty; Katz, Karol H; Kesler, Shelli; Schneider, Karen; Reiss, Allan; Ment, Laura; Spann, Marisa N

2011-06-01

This study tested the hypothesis that preterm early adolescents' short-term memory is compromised when presented with increasingly complex verbal information and that associated neuroanatomical volumes would differ between preterm and term groups. Forty-nine preterm and 20 term subjects were evaluated at age 12 years with neuropsychological measures and magnetic resonance imaging (MRI). There were no differences between groups in simple short-term and working memory. Preterm subjects performed lower on learning and short-term memory tests that included increased verbal complexity. They had reduced right parietal, left temporal, and right temporal white matter volumes and greater bilateral frontal gray and right frontal white matter volumes. There was a positive association between complex working memory and the left hippocampus and frontal white matter in term subjects. While not correlated, memory scores and volumes of cortical regions known to subserve language and memory were reduced in preterm subjects. This study provides evidence of possible mechanisms for learning problems in former preterm infants.

Short-term Memory as a Processing Shift

Science.gov (United States)

Lewis-Smith, Marion Quinn

1975-01-01

The series of experiments described here examined the predictions for free recall from sequential models and the shift formulation, focusing on the roles of short- and long-term memory in the primacy/recency shift and on the effects of expectancies on short- and long-term memory. (Author/RK)

Nurses' contribution to short-term humanitarian care in low- to middle-income countries: An integrative review of the literature.

Science.gov (United States)

Dawson, Sonja; Elliott, Doug; Jackson, Debra

2017-12-01

To appraise the literature related to voluntary humanitarian work provided by international nurses in low- to middle-income countries. Nurses and other health professionals are engaged with both governmental and nongovernmental organisations to provide care within international humanitarian relief and development contexts. Current literature describes accounts of charitable health professional activity within short-term health-focused humanitarian trips; however, there is minimal research describing the care that nurses provide and the professional roles and tasks they fulfil whilst participating in international volunteer healthcare service. Integrative review. A search of articles published between 1995-2015 was conducted using seven bibliographic databases. Inclusion criteria incorporated nurses and allied health professionals' involvement in a volunteer short-term medical team capacity. Papers describing military and/or disaster response with a service-learning focus were excluded. Nineteen papers were selected for review, description and discussion of findings. Findings revealed limited data describing the care nurses provide and the professional roles and tasks they fulfil within the context of international humanitarian short-term medical trips. Issues raised included a description of demographic data regarding participants and sending agencies, motivation for volunteer participation, perceptions of effectiveness of particular programmes and sustainability issues related to cultural, ethical or moral obligations of foreign health professionals working in a low- to middle-income countries. Study findings highlighted that although nurses are recruited and participate in health-focused humanitarian activities in low- to middle-income countries, there is extremely limited documented research about the amount and type of care that nurses specifically provide in this context. Furthermore, when identified, it is most often hidden within studies outlining services

Procedure for the delivering of personal short-term visitor dosimeters

CERN Document Server

2016-01-01

Update of the administrative procedure for delivering a personal short-term visitor dosimeter to associated members of CERN’s personnel.   Associated members of the CERN personnel may request a short term visitor dosimeter if working only in Supervised Radiation Areas and for a period of less than two months in a calendar year. Such a dosimeter is delivered without the need to provide the usual regular documents: radiation passport, certificate from the home institute or medical certificate. Periodic verification will ensure that holders of these personal dosimeters do not exceed the maximum allowed personal dose for this type of dosimeter, which is the same as the limit for members of the public at 1 mSv per year. From now on, the two-month period can be spread over a calendar year, offering greater flexibility to users coming to CERN for multiple short periods. Please return unused dosimeters Persons leaving CERN for a period of more than one month should return their dosimeter to the D...

On the relationship between short- and long-term memory

DEFF Research Database (Denmark)

Sørensen, Thomas Alrik

James (1890) divided memory into separate stores; primary and secondary – or short-term and long-term memory. The interaction between the two stores often assumes that information initially is represented in volatile short-term store before entering and consolidating in the more durable long-term......, accepted). Counter to popular beliefs this suggest that long-term memory precedes short-term memory and not vice versa....... memory system (e.g. Atkinson & Shiffrin, 1968). Short-term memory seems to provide a surprising processing bottleneck where only a very limited amount of information can be represented at any given moment (Miller, 1956; Cowan, 2001). A number of studies have investigated the nature of this processing...

Short-Term Monocular Deprivation Enhances Physiological Pupillary Oscillations

Directory of Open Access Journals (Sweden)

Paola Binda

2017-01-01

Full Text Available Short-term monocular deprivation alters visual perception in adult humans, increasing the dominance of the deprived eye, for example, as measured with binocular rivalry. This form of plasticity may depend upon the inhibition/excitation balance in the visual cortex. Recent work suggests that cortical excitability is reliably tracked by dilations and constrictions of the pupils of the eyes. Here, we ask whether monocular deprivation produces a systematic change of pupil behavior, as measured at rest, that is independent of the change of visual perception. During periods of minimal sensory stimulation (in the dark and task requirements (minimizing body and gaze movements, slow pupil oscillations, “hippus,” spontaneously appear. We find that hippus amplitude increases after monocular deprivation, with larger hippus changes in participants showing larger ocular dominance changes (measured by binocular rivalry. This tight correlation suggests that a single latent variable explains both the change of ocular dominance and hippus. We speculate that the neurotransmitter norepinephrine may be implicated in this phenomenon, given its important role in both plasticity and pupil control. On the practical side, our results indicate that measuring the pupil hippus (a simple and short procedure provides a sensitive index of the change of ocular dominance induced by short-term monocular deprivation, hence a proxy for plasticity.

The suitability of short-term measurements of radon in the built environment

International Nuclear Information System (INIS)

Denman, A.R.; Groves-Kirkby, C.J.; Phillips, P.S.; Crockett, R.G.M.; Woolridge, A.C.

2008-01-01

Although domestic and workplace radon concentration levels often show marked diurnal/short-term variation, overall health risk is determined by the long-term average level, and many national protocols advocate the use of long exposure periods, usually three months, to assess long-term risk. Simple passive measurement techniques, e.g. track-etch, activated charcoal and electret, can, however, provide reasonably accurate determinations with exposures as short as one week, and there is pressure from users and stake holders for assessments within this time period. We report evaluation of the effectiveness of one-week, one-month and three-month exposures over a period of one year in a designated Radon Affected Area in the United Kingdom (UK). Although short-term exposures did not compromise measurement accuracy, short-term radon variability rendered one-week measurements less reliable in predicting annual average radon levels via the conventional methodology. Analysis permitted estimation of the maximum and minimum short-term measured domestic radon concentrations at which there was 95% probability of the predicted annual average being below or above the UK Action Level of 200 Bq·m -3 respectively. Between these limits, the short-term result is equivocal, requiring repetition, and the 'equivocal range' for one-week measurements is significantly wider than for three-month exposures. In any geographical area, domestic radon concentrations are distributed log normally, with many properties having low average levels; a small number exhibit excessive levels, and this distribution must be considered when defining exposures for a radon measurement programme. In low-radon areas, where 1% of houses might exceed the Action Level, a one-week assessment will find that fewer outcomes are equivocal. For high-radon areas, with 20% or more houses over the Action Level, more than 50% of one-week outcomes will be equivocal, requiring repeats. The results of this work will be presented

Self-concept and quality of object relations as predictors of outcome in short- and long-term psychotherapy.

Science.gov (United States)

Lindfors, Olavi; Knekt, Paul; Heinonen, Erkki; Virtala, Esa

2014-01-01

Quality of object relations and self-concept reflect clinically relevant aspects of personality functioning, but their prediction as suitability factors for psychotherapies of different lengths has not been compared. This study compared their prediction on psychiatric symptoms and work ability in short- and long-term psychotherapy. Altogether 326 patients, 20-46 years of age, with mood and/or anxiety disorder, were randomized to short-term (solution-focused or short-term psychodynamic) psychotherapy and long-term psychodynamic psychotherapy. The Quality of Object Relations Scale (QORS) and the Structural Analysis of Social Behavior (SASB) self-concept questionnaire were measured at baseline, and their prediction on outcome during the 3-year follow-up was assessed by the Symptom Check List Global Severity Index and the Anxiety Scale, the Beck Depression Inventory and by the Work Ability Index, Social Adjustment Scale work subscale and the Perceived Psychological Functioning scale. Negative self-concept strongly and self-controlling characteristics modestly predicted better 3-year outcomes in long-term therapy, after faster early gains in short-term therapy. Patients with a more positive or self-emancipating self-concept, or more mature object relations, experienced more extensive benefits after long-term psychotherapy. The importance of length vs. long-term therapy technique on the differences found is not known. Patients with mild to moderate personality pathology, indicated by poor self-concept, seem to benefit more from long-term than short-term psychotherapy, in reducing risk of depression. Long-term therapy may also be indicated for patients with relatively good psychological functioning. More research is needed on the relative importance of these characteristics in comparison with other patient-related factors. © 2013 Published by Elsevier B.V.

WORKING MEMORY CAPACITY TEST REVEALS SUBJECTS DIFFICULTIES MANAGING LIMITED CAPACITY

Directory of Open Access Journals (Sweden)

R V Ershova

2016-12-01

Full Text Available Free recall consists of two separate stages: the emptying of working memory and reactivation [5]. The Tarnow Unchunkable Test (TUT, [7] uses double integer items to separate out only the first stage by making it difficult to reactivate items due to the lack of intra-item relationships.193 Russian college students were tested via the internet version of the TUT. The average number of items remembered in the 3 item test was 2.54 items. In the 4 item test, the average number of items decreased to 2.38. This, and a number of other qualitative distribution differences between the 3 and 4 item tests, indicate that the average capacity limit of working memory has been reached at 3 items. This provides the first direct measurement of the unchunkable capacity limit of number items.Difficulties in managing working memory occurred as most subjects remembered less as the number of items increased beyond capacity and failed to remember a single item in at least one out of three 4 item trials. The Pearson correlation between the total recall of 3 and 4 items was a small 38%.

Short-term memory and long-term memory are still different.

Science.gov (United States)

Norris, Dennis

2017-09-01

A commonly expressed view is that short-term memory (STM) is nothing more than activated long-term memory. If true, this would overturn a central tenet of cognitive psychology-the idea that there are functionally and neurobiologically distinct short- and long-term stores. Here I present an updated case for a separation between short- and long-term stores, focusing on the computational demands placed on any STM system. STM must support memory for previously unencountered information, the storage of multiple tokens of the same type, and variable binding. None of these can be achieved simply by activating long-term memory. For example, even a simple sequence of digits such as "1, 3, 1" where there are 2 tokens of the digit "1" cannot be stored in the correct order simply by activating the representations of the digits "1" and "3" in LTM. I also review recent neuroimaging data that has been presented as evidence that STM is activated LTM and show that these data are exactly what one would expect to see based on a conventional 2-store view. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Serial consolidation of orientation information into visual short-term memory.

Science.gov (United States)

Liu, Taosheng; Becker, Mark W

2013-06-01

Previous research suggests that there is a limit to the rate at which items can be consolidated in visual short-term memory (VSTM). This limit could be due to either a serial or a limited-capacity parallel process. Historically, it has proven difficult to distinguish between these two types of processes. In the present experiment, we took a novel approach that allowed us to do so. Participants viewed two oriented gratings either sequentially or simultaneously and reported one of the gratings' orientation via method of adjustment. Performance was worse for the simultaneous than for the sequential condition. We fit the data with a mixture model that assumes performance is limited by a noisy memory representation plus random guessing. Critically, the serial and limited-capacity parallel processes made distinct predictions regarding the model's guessing and memory-precision parameters. We found strong support for a serial process, which implies that one can consolidate only a single orientation into VSTM at a time.

Electrophysiological indices of altered working memory processes in long-term ecstasy users.

Science.gov (United States)

Nulsen, Claire; Fox, Allison; Hammond, Geoff

2011-10-01

The aim of this study was to determine the effect of light long-term ecstasy consumption on verbal short-term and working memory and to identify the cognitive processes contributing to task performance. Electroencephalogram was recorded while ecstasy users (N = 11), polydrug users (N = 13), and non-users (N = 13) completed forward and backward serial recognition tasks designed to engage verbal short-term memory and verbal working memory, respectively. All three groups displayed significantly lower digit-backward span than digit-forward span with ecstasy users displaying the greatest difference. The parietally distributed P3b was significantly smaller in the digits backward task than in the digits forward task in non-ecstasy-using controls. Ecstasy users did not show the reduced P3b component in the backward task that was seen in both non-ecstasy-using control groups. Ecstasy users' performance was suppressed more by the concurrent processing demands of the working memory task than that of the non-ecstasy-using controls. Non-ecstasy-using controls showed differential event-related potential wave forms in the short-term and working memory tasks, and this pattern was not seen in the ecstasy users. This is consistent with a reduction in the cognitive resources allocated to processing in working memory in ecstasy users. Copyright © 2011 John Wiley & Sons, Ltd.

How do verbal short-term memory and working memory relate to the acquisition of vocabulary and grammar? : A comparison between first and second language learners

NARCIS (Netherlands)

Verhagen, Josje; Leseman, Paul

Previous studies show that verbal short-term memory (VSTM) is related to vocabulary learning, whereas verbal working memory (VWM) is related to grammar learning in children learning a second language (L2) in the classroom. In this study, we investigated whether the same relationships apply to

Performance of batteries for electric vehicles on short and longer term

NARCIS (Netherlands)

Gerssen - Gondelach, Sarah|info:eu-repo/dai/nl/355262436; Faaij, André P C|info:eu-repo/dai/nl/10685903X

2012-01-01

In this work, the prospects of available and new battery technologies for battery electric vehicles (BEVs) are examined. Five selected battery technologies are assessed on battery performance and cost in the short, medium and long term. Driving cycle simulations are carried out to assess the

Short-term power plant operation scheduling in thermal systems with long-term boundary conditions

International Nuclear Information System (INIS)

Wolter, H.

1990-01-01

For the first time, the modeling of long-term quantitative conditions within the short-term planning of the application of power stations is made via their shadow prices. It corresponds to a decomposition of the quantitative conditions by means of the method of the Langrange relaxation. The shadow prices determined by the planning for energy application regarding long- term quantitative conditions pass into the short-term planning for power station application and subsidize or rather punish the application of limited amounts as for as they are not claimed for sufficiently or excessively. The clear advantage of this modeling is that the short-term planning of power station application can deviate from the envisioned energy application regarding the total optimum, because the shadow prices contain all information about the cost effect of the energy shifts in the residual total period, which become necessary due to the deviations in the short-term period to be planned in the current short-term period. (orig./DG) [de

Improving creativity performance by short-term meditation

Science.gov (United States)

2014-01-01

Background One form of meditation intervention, the integrative body-mind training (IBMT) has been shown to improve attention, reduce stress and change self-reports of mood. In this paper we examine whether short-term IBMT can improve performance related to creativity and determine the role that mood may play in such improvement. Methods Forty Chinese undergraduates were randomly assigned to short-term IBMT group or a relaxation training (RT) control group. Mood and creativity performance were assessed by the Positive and Negative Affect Schedule (PANAS) and Torrance Tests of Creative Thinking (TTCT) questionnaire respectively. Results As predicted, the results indicated that short-term (30 min per day for 7 days) IBMT improved creativity performance on the divergent thinking task, and yielded better emotional regulation than RT. In addition, cross-lagged analysis indicated that both positive and negative affect may influence creativity in IBMT group (not RT group). Conclusions Our results suggested that emotion-related creativity-promoting mechanism may be attributed to short-term meditation. PMID:24645871

Testing visual short-term memory of pigeons (Columba livia) and a rhesus monkey (Macaca mulatta) with a location change detection task.

Science.gov (United States)

Leising, Kenneth J; Elmore, L Caitlin; Rivera, Jacquelyne J; Magnotti, John F; Katz, Jeffrey S; Wright, Anthony A

2013-09-01

Change detection is commonly used to assess capacity (number of objects) of human visual short-term memory (VSTM). Comparisons with the performance of non-human animals completing similar tasks have shown similarities and differences in object-based VSTM, which is only one aspect ("what") of memory. Another important aspect of memory, which has received less attention, is spatial short-term memory for "where" an object is in space. In this article, we show for the first time that a monkey and pigeons can be accurately trained to identify location changes, much as humans do, in change detection tasks similar to those used to test object capacity of VSTM. The subject's task was to identify (touch/peck) an item that changed location across a brief delay. Both the monkey and pigeons showed transfer to delays longer than the training delay, to greater and smaller distance changes than in training, and to novel colors. These results are the first to demonstrate location-change detection in any non-human species and encourage comparative investigations into the nature of spatial and visual short-term memory.

Models of verbal working memory capacity: what does it take to make them work?

Science.gov (United States)

Cowan, Nelson; Rouder, Jeffrey N; Blume, Christopher L; Saults, J Scott

2012-07-01

Theories of working memory (WM) capacity limits will be more useful when we know what aspects of performance are governed by the limits and what aspects are governed by other memory mechanisms. Whereas considerable progress has been made on models of WM capacity limits for visual arrays of separate objects, less progress has been made in understanding verbal materials, especially when words are mentally combined to form multiword units or chunks. Toward a more comprehensive theory of capacity limits, we examined models of forced-choice recognition of words within printed lists, using materials designed to produce multiword chunks in memory (e.g., leather brief case). Several simple models were tested against data from a variety of list lengths and potential chunk sizes, with test conditions that only imperfectly elicited the interword associations. According to the most successful model, participants retained about 3 chunks on average in a capacity-limited region of WM, with some chunks being only subsets of the presented associative information (e.g., leather brief case retained with leather as one chunk and brief case as another). The addition to the model of an activated long-term memory component unlimited in capacity was needed. A fixed-capacity limit appears critical to account for immediate verbal recognition and other forms of WM. We advance a model-based approach that allows capacity to be assessed despite other important processing contributions. Starting with a psychological-process model of WM capacity developed to understand visual arrays, we arrive at a more unified and complete model. Copyright 2012 APA, all rights reserved.

Simple Predictions Fueled by Capacity Limitations: When Are They Successful?

Science.gov (United States)

Gaissmaier, Wolfgang; Schooler, Lael J.; Rieskamp, Jorg

2006-01-01

Counterintuitively, Y. Kareev, I. Lieberman, and M. Lev (1997) found that a lower short-term memory capacity benefits performance on a correlation detection task. They assumed that people with low short-term memory capacity (low spans) perceived the correlations as more extreme because they relied on smaller samples, which are known to exaggerate…

Using electrophysiology to demonstrate that cueing affects long-term memory storage over the short term.

Science.gov (United States)

Maxcey, Ashleigh M; Fukuda, Keisuke; Song, Won S; Woodman, Geoffrey F

2015-10-01

As researchers who study working memory, we often assume that participants keep a representation of an object in working memory when we present a cue that indicates that the object will be tested in a couple of seconds. This intuitively accounts for how well people can remember a cued object, relative to their memory for that same object presented without a cue. However, it is possible that this superior memory does not purely reflect storage of the cued object in working memory. We tested the hypothesis that cues presented during a stream of objects, followed by a short retention interval and immediate memory test, can change how information is handled by long-term memory. We tested this hypothesis by using a family of frontal event-related potentials believed to reflect long-term memory storage. We found that these frontal indices of long-term memory were sensitive to the task relevance of objects signaled by auditory cues, even when the objects repeated frequently, such that proactive interference was high. Our findings indicate the problematic nature of assuming process purity in the study of working memory, and demonstrate that frequent stimulus repetitions fail to isolate the role of working memory mechanisms.

Development of verbal short-term memory and working memory in children with epilepsy: Developmental delay and impact of time-related variables. A cross-sectional study.

Science.gov (United States)

van Iterson, Loretta; de Jong, Peter F

2018-01-01

While short-term memory (STM) and working memory (WM) are understood as being crucial for learning, and children with epilepsy often experience learning difficulties, little is known about the age-related development of memory span tasks in children with epilepsy. Short-term memory and WM, operationalized as digit span forwards (DSF) or digit span backwards (DSB), respectively, were studied. Participants were 314 children with epilepsy and 327 typically developing children in ages between 5 and 15years and full scale intelligence quotient (FS-IQ)≥75. Cross-sectional analyses of the data were done with analyses of variance and analyses of covariance ((M)ANCOVAs) and generalized linear analyses. The analyses revealed that STM problems in epilepsy were mediated by age-related gains in WM as well as by differences in IQ. Working memory developed at a quick pace in the younger children, the pace slowed down to some extent in the later primary school years and resumed again later on. Working memory problems prevailed in epilepsy, independent of IQ and development of STM. Timing of the epilepsy in terms of age at onset and duration determined memory development. The youngest children with epilepsy showed age-appropriate development in STM but were the most vulnerable in terms of WM development. Later in the course of the epilepsy, the WM problems of the young children attenuated. In later onset epilepsy, WM problems were smaller but persisted over time. Copyright © 2017 Elsevier Inc. All rights reserved.

Evaluation of a brief anti-stigma campaign in Cambridge: do short-term campaigns work?

Science.gov (United States)

Evans-Lacko, Sara; London, Jillian; Little, Kirsty; Henderson, Claire; Thornicroft, Graham

2010-06-14

In view of the high costs of mass-media campaigns, it is important to understand whether it is possible for a media campaign to have significant population effects over a short period of time. This paper explores this question specifically in reference to stigma and discrimination against people with mental health problems using the Time to Change Cambridge anti-stigma campaign as an example. 410 face-to-face interviews were performed pre, during and post campaign activity to assess campaign awareness and mental health-related knowledge, attitudes and behaviours. Although campaign awareness was not sustained following campaign activity, significant and sustained shifts occurred for mental health-related knowledge items. Specifically, there was a 24% (p mental health problem, I know what advice to give them to get professional help, following the campaign. Additionally, for the statement: Medication can be an effective treatment for people with mental health problems, there was a 10% rise (p = 0.05) in the proportion of interviewees responding 'agree' or 'strongly agree' following the campaign. These changes, however, were not evident for attitudinal or behaviour related questions. Although these results only reflect the impact of one small scale campaign, these preliminary findings suggest several considerations for mass-media campaign development and evaluation strategies such as: (1) Aiming to influence outcomes pertaining to knowledge in the short term; (2) Planning realistic and targeted outcomes over the short, medium and long term during sustained campaigns; and (3) Monitoring indirect campaign effects such as social discourse or other social networking/contact in the evaluation.

Standardizing the performance evaluation of short-term wind prediction models

DEFF Research Database (Denmark)

Madsen, Henrik; Pinson, Pierre; Kariniotakis, G.

2005-01-01

Short-term wind power prediction is a primary requirement for efficient large-scale integration of wind generation in power systems and electricity markets. The choice of an appropriate prediction model among the numerous available models is not trivial, and has to be based on an objective...... evaluation of model performance. This paper proposes a standardized protocol for the evaluation of short-term wind-poser preciction systems. A number of reference prediction models are also described, and their use for performance comparison is analysed. The use of the protocol is demonstrated using results...... from both on-shore and off-shore wind forms. The work was developed in the frame of the Anemos project (EU R&D project) where the protocol has been used to evaluate more than 10 prediction systems....

Short-term energy outlook, annual supplement 1994

International Nuclear Information System (INIS)

1994-08-01

The Short-Term Energy Outlook Annual Supplement (Supplement) is published once a year as a complement to the Short-Term Energy Outlook (Outlook), Quarterly Projections. The purpose of the Supplement is to review the accuracy of the forecasts published in the Outlook, make comparisons with other independent energy forecasts, and examine current energy topics that affect the forecasts

Short-term energy outlook annual supplement, 1993

Energy Technology Data Exchange (ETDEWEB)

NONE

1993-08-06

The Short-Term Energy Outlook Annual Supplement (supplement) is published once a year as a complement to the Short-Term Energy Outlook (Outlook), Quarterly Projections. The purpose of the Supplement is to review the accuracy of the forecasts published in the Outlook, make comparisons with other independent energy forecasts, and examine current energy topics that affect the forecasts.

The Performance of Short-Term Heart Rate Variability in the Detection of Congestive Heart Failure

Directory of Open Access Journals (Sweden)

Fausto Lucena

2016-01-01

Full Text Available Congestive heart failure (CHF is a cardiac disease associated with the decreasing capacity of the cardiac output. It has been shown that the CHF is the main cause of the cardiac death around the world. Some works proposed to discriminate CHF subjects from healthy subjects using either electrocardiogram (ECG or heart rate variability (HRV from long-term recordings. In this work, we propose an alternative framework to discriminate CHF from healthy subjects by using HRV short-term intervals based on 256 RR continuous samples. Our framework uses a matching pursuit algorithm based on Gabor functions. From the selected Gabor functions, we derived a set of features that are inputted into a hybrid framework which uses a genetic algorithm and k-nearest neighbour classifier to select a subset of features that has the best classification performance. The performance of the framework is analyzed using both Fantasia and CHF database from Physionet archives which are, respectively, composed of 40 healthy volunteers and 29 subjects. From a set of nonstandard 16 features, the proposed framework reaches an overall accuracy of 100% with five features. Our results suggest that the application of hybrid frameworks whose classifier algorithms are based on genetic algorithms has outperformed well-known classifier methods.

Effect of a participatory organizational-level occupational health intervention on short-term sickness absence

DEFF Research Database (Denmark)

Framke, Elisabeth; Sørensen, Ole Henning; Pedersen, Jacob

2016-01-01

with a crude RR of 0.83 (95% CI 0.69–0.99) and an adjusted RR of 0.84 (95% CI 0.69–1.01). Conclusions: Pre-school employees participating in an organizational-level occupational health intervention focusing on the core task at work had a lower incidence of short-term sickness absence during a 29-month follow......Objectives: The aim of this study was to examine whether employees in pre-schools that implemented a participatory organizational-level intervention focusing on the core task at work had a lower incidence of short-term sickness absence compared to employees in the control group. Methods...

Short Term Memory, Working Memory, and Syntactic Comprehension in Aphasia

Science.gov (United States)

Caplan, David; Michaud, Jennifer; Hufford, Rebecca

2013-01-01

Sixty one people with aphasia were tested on ten tests of short term memory (STM) and for the ability to use syntactic structure to determine the meanings of eleven types of sentences in three tasks – object manipulation, picture matching and picture matching with self-paced listening. Multilevel models showed relationships between measures of the ability to retain and manipulate item and order information in STM and accuracy and RT, and a greater relationship between these STM measures and accuracy and RT for several more complex sentence types in individual tasks. There were no effects of measures of STM that reflect the use of phonological codes or rehearsal on comprehension. There was only one effect of STM measures on self-paced listening times. There were double dissociations between performance on STM and individual comprehension tasks, indicating that normal STM is not necessary to perform normally on these tasks. The results are most easily related to the view that STM plays a facilitatory role in supporting the use of the products of the comprehension process to accomplish operations related to tasks. PMID:23865692

Variation in Working Memory Capacity and Temporal-Contextual Retrieval from Episodic Memory

Science.gov (United States)

Spillers, Gregory J.; Unsworth, Nash

2011-01-01

Unsworth and Engle (2007) recently proposed a model of working memory capacity characterized by, among other things, the ability to conduct a strategic, cue-dependent search of long-term memory. Although this ability has been found to mediate individual variation in a number of higher order cognitive tasks, the component processes involved remain…

Short-Term Memory in Mathematics-Proficient and Mathematics-Disabled Students as a Function of Input-Modality/Output-Modality Pairings.

Science.gov (United States)

Webster, Raymond E.

1980-01-01

A significant two-way input modality by output modality interaction suggested that short term memory capacity among the groups differed as a function of the modality used to present the items in combination with the output response required. (Author/CL)

The influence of working memory capacity on experimental heat pain.

Science.gov (United States)

Nakae, Aya; Endo, Kaori; Adachi, Tomonori; Ikeda, Takashi; Hagihira, Satoshi; Mashimo, Takashi; Osaka, Mariko

2013-10-01

Pain processing and attention have a bidirectional interaction that depends upon one's relative ability to use limited-capacity resources. However, correlations between the size of limited-capacity resources and pain have not been evaluated. Working memory capacity, which is a cognitive resource, can be measured using the reading span task (RST). In this study, we hypothesized that an individual's potential working memory capacity and subjective pain intensity are related. To test this hypothesis, we evaluated 31 healthy participants' potential working memory capacity using the RST, and then applied continuous experimental heat stimulation using the listening span test (LST), which is a modified version of the RST. Subjective pain intensities were significantly lower during the challenging parts of the RST. The pain intensity under conditions where memorizing tasks were performed was compared with that under the control condition, and it showed a correlation with potential working memory capacity. These results indicate that working memory capacity reflects the ability to process information, including precise evaluations of changes in pain perception. In this work, we present data suggesting that changes in subjective pain intensity are related, depending upon individual potential working memory capacities. Individual working memory capacity may be a phenotype that reflects sensitivity to changes in pain perception. Copyright © 2013 American Pain Society. Published by Elsevier Inc. All rights reserved.

Short-term mindfulness intervention reduces the negative attentional effects associated with heavy media multitasking.

Science.gov (United States)

Gorman, Thomas E; Green, C Shawn

2016-04-18

Recent research suggests that frequently switching between various forms of media (i.e. 'media multitasking') is associated with diminished attentional abilities, a disconcerting result given the prevalence of media multitasking in today's society. In the present study, we sought to investigate the extent to which the deficits associated with frequent media multitasking can be temporarily ameliorated via a short-term mindfulness intervention previously shown to produce beneficial effects on the attentional abilities of normally functioning individuals. Consistent with previous work, we found: (1) that heavy media multitaskers showed generally poorer attentional abilities than light media multitaskers and (2) that all participants showed benefits from the short-term mindfulness intervention. Furthermore, we found that the benefits of the short-term mindfulness intervention were not equivalently large across participants. Instead, these benefits were disproportionately large in the heavy media multitaskers. While the positive outcomes were short-lived, this opens the possibility of performing long-term interventions with the goal of realizing lasting gains in this population.

In Search of Decay in Verbal Short-Term Memory

Science.gov (United States)

Berman, Marc G.; Jonides, John; Lewis, Richard L.

2009-01-01

Is forgetting in the short term due to decay with the mere passage of time, interference from other memoranda, or both? Past research on short-term memory has revealed some evidence for decay and a plethora of evidence showing that short-term memory is worsened by interference. However, none of these studies has directly contrasted decay and…

Short-Term and Long-Term Outcomes of a Vocational Rehabilitation Program for Patients with Acquired Brain Injury in The Netherlands

NARCIS (Netherlands)

van Dongen, Caroline H.; Goossens, Paulien H.; van Zee, Inge E.; Verpoort, Kirsten N.; Vliet Vlieland, Thea P. M.; van Velzen, Judith M.

2017-01-01

Purpose To describe short-term and long-term work status after a vocational rehabilitation (VR) program in patients with acquired brain injury (ABI) in the Netherlands. Methods Patients with ABI who participated in a VR program between 2007 and 2010 were included in this study. The 4-month VR

Attention Problems, Phonological Short-Term Memory, and Visuospatial Short-Term Memory: Differential Effects on Near- and Long-Term Scholastic Achievement

Science.gov (United States)

Sarver, Dustin E.; Rapport, Mark D.; Kofler, Michael J.; Scanlan, Sean W.; Raiker, Joseph S.; Altro, Thomas A.; Bolden, Jennifer

2012-01-01

The current study examined individual differences in children's phonological and visuospatial short-term memory as potential mediators of the relationship among attention problems and near- and long-term scholastic achievement. Nested structural equation models revealed that teacher-reported attention problems were associated negatively with…

Cognitive aging on latent constructs for visual processing capacity

DEFF Research Database (Denmark)

Nielsen, Simon; Wilms, Inge Linda

2015-01-01

processing speed compared to visual short-term memory (VSTM) capacity (Model 2). These results are consistent with some studies reporting selective ageing effects on processing speed, and inconsistent with other studies reporting ageing effects on both processing speed and VSTM capacity. In the discussion we......We examined the effects of normal ageing on visual cognition in a sample of 112 healthy adults aged 60-75. A testbattery was designed to capture high-level measures of visual working memory and low-level measures of visuospatial attention and memory. To answer questions of how cognitive ageing...

Musicians' and nonmusicians' short-term memory for verbal and musical sequences: comparing phonological similarity and pitch proximity.

Science.gov (United States)

Williamson, Victoria J; Baddeley, Alan D; Hitch, Graham J

2010-03-01

Language-music comparative studies have highlighted the potential for shared resources or neural overlap in auditory short-term memory. However, there is a lack of behavioral methodologies for comparing verbal and musical serial recall. We developed a visual grid response that allowed both musicians and nonmusicians to perform serial recall of letter and tone sequences. The new method was used to compare the phonological similarity effect with the impact of an operationalized musical equivalent-pitch proximity. Over the course of three experiments, we found that short-term memory for tones had several similarities to verbal memory, including limited capacity and a significant effect of pitch proximity in nonmusicians. Despite being vulnerable to phonological similarity when recalling letters, however, musicians showed no effect of pitch proximity, a result that we suggest might reflect strategy differences. Overall, the findings support a limited degree of correspondence in the way that verbal and musical sounds are processed in auditory short-term memory.

A short-term study of the state of surface water acidification at Semenyih dam

International Nuclear Information System (INIS)

Kantasamy, Nesamalar; Sumari, S.M.; Salam, S.M.; Riniswani Aziz

2007-01-01

A short-term study was done to analyze the state of acidification of surface water at Semenyih Dam. This study is part of a continuous monitoring programme for Malaysia as a participatory country of EANET (Acid Monitoring Network in East Asia). Surface water samples were taken at selected points of the dam from February to December 2005. Temperature, electrical conductivity, pH, alkalinity, acid neutralizing capacity (ANC) as well as concentration of specific ionic species were measured, determined and analysed in this study. Present available sort-term study data indicates Semenyih Dam surface water is currently not undergoing acidification. (author)

Reduced volume and increased training intensity elevate muscle Na+/K+ pump {alpha}2-subunit expression as well as short- and long-term work capacity in humans

DEFF Research Database (Denmark)

Bangsbo, Jens; Gunnarsson, Thomas Petursson; Wendell, Jesper

2009-01-01

was unaltered, but the 3-K (3,000 m) time was reduced (Pexpression and performance remained unaltered in CON. The present data suggest that both short- and long-term......% reduction in the amount of training but including speed endurance training consisting of 6-12 30-s sprint runs 3-4 times a week (SET, n=12) or a control group (CON, n=5), which continued the endurance training (about 55 km(.)wk(-1)). For SET the expression of the muscle Na(+)/K(+) pump alpha2-subunit was 68...

The Contribution of Short-Term Memory for Serial Order to Early Reading Acquisition: Evidence from a Longitudinal Study

Science.gov (United States)

Perez, Trecy Martinez; Majerus, Steve; Poncelet, Martine

2012-01-01

Early reading acquisition skills have been linked to verbal short-term memory (STM) capacity. However, the nature of this relationship remains controversial because verbal STM, like reading acquisition, depends on the complexity of underlying phonological processing skills. This longitudinal study addressed the relation between STM and reading…

Auditory short-term memory in the primate auditory cortex.

Science.gov (United States)

Scott, Brian H; Mishkin, Mortimer

2016-06-01

Sounds are fleeting, and assembling the sequence of inputs at the ear into a coherent percept requires auditory memory across various time scales. Auditory short-term memory comprises at least two components: an active ׳working memory' bolstered by rehearsal, and a sensory trace that may be passively retained. Working memory relies on representations recalled from long-term memory, and their rehearsal may require phonological mechanisms unique to humans. The sensory component, passive short-term memory (pSTM), is tractable to study in nonhuman primates, whose brain architecture and behavioral repertoire are comparable to our own. This review discusses recent advances in the behavioral and neurophysiological study of auditory memory with a focus on single-unit recordings from macaque monkeys performing delayed-match-to-sample (DMS) tasks. Monkeys appear to employ pSTM to solve these tasks, as evidenced by the impact of interfering stimuli on memory performance. In several regards, pSTM in monkeys resembles pitch memory in humans, and may engage similar neural mechanisms. Neural correlates of DMS performance have been observed throughout the auditory and prefrontal cortex, defining a network of areas supporting auditory STM with parallels to that supporting visual STM. These correlates include persistent neural firing, or a suppression of firing, during the delay period of the memory task, as well as suppression or (less commonly) enhancement of sensory responses when a sound is repeated as a ׳match' stimulus. Auditory STM is supported by a distributed temporo-frontal network in which sensitivity to stimulus history is an intrinsic feature of auditory processing. This article is part of a Special Issue entitled SI: Auditory working memory. Published by Elsevier B.V.

Short-Term Reciprocity in Late Parent-Child Relationships

Science.gov (United States)

Leopold, Thomas; Raab, Marcel

2011-01-01

Long-term concepts of parent-child reciprocity assume that the amount of support given and received is only balanced in a generalized fashion over the life course. We argue that reciprocity in parent-child relationships also operates in the short term. Our analysis of short-term reciprocity focuses on concurrent exchange in its main upward and…

Short-Term Memory for Serial Order: A Recurrent Neural Network Model

Science.gov (United States)

Botvinick, Matthew M.; Plaut, David C.

2006-01-01

Despite a century of research, the mechanisms underlying short-term or working memory for serial order remain uncertain. Recent theoretical models have converged on a particular account, based on transient associations between independent item and context representations. In the present article, the authors present an alternative model, according…

Implementing a short-term loyalty program : case: Bosch Lawn & Garden and the Ventum short-term loyalty program

OpenAIRE

Logvinova, Veronika

2015-01-01

In 2015, one of the Bosch Home and Garden divisions, Bosch Lawn and Garden, has made a strategic decision to adopt a points-based short-term loyalty program called Ventum LG in the German supermarkets and petrol stations. It was decided that the base of this program will be completed Ventum PT short-term loyalty program which was managed by another division, Bosch Power Tools, and proved to be successful. This thesis aims to evaluate the worthiness of the Ventum LG loyalty program for Bosch L...

Short-term energy outlook annual supplement, 1993

International Nuclear Information System (INIS)

1993-01-01

The Energy Information Administration (EIA) prepares quarterly, short-term energy supply, demand, and price projections for publication in February, May, August, and November in the Short-Term Energy Outlook (Outlook). An annual supplement analyzes the performance of previous forecasts, compares recent cases with those of other forecasting services, and discusses current topics related to the short-term energy markets. (See Short-Term Energy Outlook Annual Supplement, DOE/EIA-0202.) The forecast period for this issue of the Outlook extends from the third quarter of 1993 through the fourth quarter of 1994. Values for the second quarter of 1993, however, are preliminary EIA estimates (for example, some monthly values for petroleum supply and disposition are derived in part from weekly data reported in the Weekly Petroleum Status Report) or are calculated from model simulations using the latest exogenous information available (for example, electricity sales and generation are simulated using actual weather data). The historical energy data are EIA data published in the Monthly Energy Review, Petroleum Supply Monthly, and other EIA publications. Minor discrepancies between the data in these publications and the historical data in this Outlook are due to independent rounding

Working memory, long-term memory and language processing : issues and future directions

OpenAIRE

Collette, Fabienne; Van der Linden, Martial; Poncelet, Martine

2000-01-01

We examined different views of the relationships between working memory, long-term memory and language processing : working memory considered as a gateway between sensory input and long-term memory or rather as a workspace; working memory considered as not strictly tied to any particular cognitive system (and consequently viewed as separated from the language system) or rather as drawing on the operation and storage capacities of a subset of components involved in language processing. It is a...

Working memory capacity and task goals modulate error-related ERPs.

Science.gov (United States)

Coleman, James R; Watson, Jason M; Strayer, David L

2018-03-01

The present study investigated individual differences in information processing following errant behavior. Participants were initially classified as high or as low working memory capacity using the Operation Span Task. In a subsequent session, they then performed a high congruency version of the flanker task under both speed and accuracy stress. We recorded ERPs and behavioral measures of accuracy and response time in the flanker task with a primary focus on processing following an error. The error-related negativity was larger for the high working memory capacity group than for the low working memory capacity group. The positivity following an error (Pe) was modulated to a greater extent by speed-accuracy instruction for the high working memory capacity group than for the low working memory capacity group. These data help to explicate the neural bases of individual differences in working memory capacity and cognitive control. © 2017 Society for Psychophysiological Research.

Long-term effects of interference on short-term memory performance in the rat.

Science.gov (United States)

Missaire, Mégane; Fraize, Nicolas; Joseph, Mickaël Antoine; Hamieh, Al Mahdy; Parmentier, Régis; Marighetto, Aline; Salin, Paul Antoine; Malleret, Gaël

2017-01-01

A distinction has always been made between long-term and short-term memory (also now called working memory, WM). The obvious difference between these two kinds of memory concerns the duration of information storage: information is supposedly transiently stored in WM while it is considered durably consolidated into long-term memory. It is well acknowledged that the content of WM is erased and reset after a short time, to prevent irrelevant information from proactively interfering with newly stored information. In the present study, we used typical WM radial maze tasks to question the brief lifespan of spatial WM content in rodents. Groups of rats were submitted to one of two different WM tasks in a radial maze: a WM task involving the repetitive presentation of a same pair of arms expected to induce a high level of proactive interference (PI) (HIWM task), or a task using a different pair in each trial expected to induce a low level of PI (LIWM task). Performance was effectively lower in the HIWM group than in LIWM in the final trial of each training session, indicative of a "within-session/short-term" PI effect. However, we also observed a different "between-session/long-term" PI effect between the two groups: while performance of LIWM trained rats remained stable over days, the performance of HIWM rats dropped after 10 days of training, and this impairment was visible from the very first trial of the day, hence not attributable to within-session PI. We also showed that a 24 hour-gap across training sessions known to allow consolidation processes to unfold, was a necessary and sufficient condition for the long-term PI effect to occur. These findings suggest that in the HIWM task, WM content was not entirely reset between training sessions and that, in specific conditions, WM content can outlast its purpose by being stored more permanently, generating a long-term deleterious effect of PI. The alternative explanation is that WM content could be transferred and stored

Long-term effects of interference on short-term memory performance in the rat.

Directory of Open Access Journals (Sweden)

Mégane Missaire

Full Text Available A distinction has always been made between long-term and short-term memory (also now called working memory, WM. The obvious difference between these two kinds of memory concerns the duration of information storage: information is supposedly transiently stored in WM while it is considered durably consolidated into long-term memory. It is well acknowledged that the content of WM is erased and reset after a short time, to prevent irrelevant information from proactively interfering with newly stored information. In the present study, we used typical WM radial maze tasks to question the brief lifespan of spatial WM content in rodents. Groups of rats were submitted to one of two different WM tasks in a radial maze: a WM task involving the repetitive presentation of a same pair of arms expected to induce a high level of proactive interference (PI (HIWM task, or a task using a different pair in each trial expected to induce a low level of PI (LIWM task. Performance was effectively lower in the HIWM group than in LIWM in the final trial of each training session, indicative of a "within-session/short-term" PI effect. However, we also observed a different "between-session/long-term" PI effect between the two groups: while performance of LIWM trained rats remained stable over days, the performance of HIWM rats dropped after 10 days of training, and this impairment was visible from the very first trial of the day, hence not attributable to within-session PI. We also showed that a 24 hour-gap across training sessions known to allow consolidation processes to unfold, was a necessary and sufficient condition for the long-term PI effect to occur. These findings suggest that in the HIWM task, WM content was not entirely reset between training sessions and that, in specific conditions, WM content can outlast its purpose by being stored more permanently, generating a long-term deleterious effect of PI. The alternative explanation is that WM content could be

Evaluation of a brief anti-stigma campaign in Cambridge: do short-term campaigns work?

Directory of Open Access Journals (Sweden)

Henderson Claire

2010-06-01

Full Text Available Abstract Background In view of the high costs of mass-media campaigns, it is important to understand whether it is possible for a media campaign to have significant population effects over a short period of time. This paper explores this question specifically in reference to stigma and discrimination against people with mental health problems using the Time to Change Cambridge anti-stigma campaign as an example. Methods 410 face-to-face interviews were performed pre, during and post campaign activity to assess campaign awareness and mental health-related knowledge, attitudes and behaviours. Results Although campaign awareness was not sustained following campaign activity, significant and sustained shifts occurred for mental health-related knowledge items. Specifically, there was a 24% (p If a friend had a mental health problem, I know what advice to give them to get professional help, following the campaign. Additionally, for the statement: Medication can be an effective treatment for people with mental health problems, there was a 10% rise (p = 0.05 in the proportion of interviewees responding 'agree' or 'strongly agree' following the campaign. These changes, however, were not evident for attitudinal or behaviour related questions. Conclusions Although these results only reflect the impact of one small scale campaign, these preliminary findings suggest several considerations for mass-media campaign development and evaluation strategies such as: (1 Aiming to influence outcomes pertaining to knowledge in the short term; (2 Planning realistic and targeted outcomes over the short, medium and long term during sustained campaigns; and (3 Monitoring indirect campaign effects such as social discourse or other social networking/contact in the evaluation.

Music Learning with Long Short Term Memory Networks

OpenAIRE

Colombo, Florian François

2015-01-01

Humans are able to learn and compose complex, yet beautiful, pieces of music as seen in e.g. the highly complicated works of J.S. Bach. However, how our brain is able to store and produce these very long temporal sequences is still an open question. Long short-term memory (LSTM) artificial neural networks have been shown to be efficient in sequence learning tasks thanks to their inherent ability to bridge long time lags between input events and their target signals. Here, I investigate the po...

Measuring, Predicting and Visualizing Short-Term Change in Word Representation and Usage in VKontakte Social Network

Energy Technology Data Exchange (ETDEWEB)

Stewart, Ian B.; Arendt, Dustin L.; Bell, Eric B.; Volkova, Svitlana

2017-05-17

Language in social media is extremely dynamic: new words emerge, trend and disappear, while the meaning of existing words can fluctuate over time. This work addresses several important tasks of visualizing and predicting short term text representation shift, i.e. the change in a word’s contextual semantics. We study the relationship between short-term concept drift and representation shift on a large social media corpus – VKontakte collected during the Russia-Ukraine crisis in 2014 – 2015. We visualize short-term representation shift for example keywords and build predictive models to forecast short-term shifts in meaning from previous meaning as well as from concept drift. We show that short-term representation shift can be accurately predicted up to several weeks in advance and that visualization provides insight into meaning change. Our approach can be used to explore and characterize specific aspects of the streaming corpus during crisis events and potentially improve other downstream classification tasks including real-time event forecasting in social media.

Strengthening capacity for monitoring and evaluation through short course training in Kenya

Directory of Open Access Journals (Sweden)

Hesborn Wao

2017-04-01

Conclusions: This study provides preliminary evidence of potential of the use of short course training as an approach to strengthening capacity in M&E in less-developed countries such as Kenya. It underscores the importance of participants’ self-stated objective(s as an element to be considered in the enhancement of knowledge, attitudes and skills needed for acceptable capacity building in M&E.

Visual working memory buffers information retrieved from visual long-term memory.

Science.gov (United States)

Fukuda, Keisuke; Woodman, Geoffrey F

2017-05-16

Human memory is thought to consist of long-term storage and short-term storage mechanisms, the latter known as working memory. Although it has long been assumed that information retrieved from long-term memory is represented in working memory, we lack neural evidence for this and need neural measures that allow us to watch this retrieval into working memory unfold with high temporal resolution. Here, we show that human electrophysiology can be used to track information as it is brought back into working memory during retrieval from long-term memory. Specifically, we found that the retrieval of information from long-term memory was limited to just a few simple objects' worth of information at once, and elicited a pattern of neurophysiological activity similar to that observed when people encode new information into working memory. Our findings suggest that working memory is where information is buffered when being retrieved from long-term memory and reconcile current theories of memory retrieval with classic notions about the memory mechanisms involved.

Parent-Offspring Conflict over Short-Term Mating Strategies

Directory of Open Access Journals (Sweden)

Spyroulla Georgiou

2011-12-01

Full Text Available Individuals engage in short-term mating strategies that enable them to obtain fitness benefits from casual relationships. These benefits, however, count for less and cost more to their parents. On this basis three hypotheses are tested. First, parents and offspring are likely to disagree over short-term mating strategies, with the former considering these as less acceptable than the latter. Second, parents are more likely to disapprove of the short-term mating strategies of their daughters than of their sons. Finally, mothers and fathers are expected to agree on how much they disagree over the short-term mating strategies of their children. Evidence from a sample of 148 Greek-Cypriot families (140 mothers, 105 fathers, 119 daughters, 77 sons provides support for the first two hypotheses and partial support for the third hypothesis. The implications of these findings for understanding family dynamics are further discussed.

Effects of strategy on visual working memory capacity.

Science.gov (United States)

Bengson, Jesse J; Luck, Steven J

2016-02-01

Substantial evidence suggests that individual differences in estimates of working memory capacity reflect differences in how effectively people use their intrinsic storage capacity. This suggests that estimated capacity could be increased by instructions that encourage more effective encoding strategies. The present study tested this by giving different participants explicit strategy instructions in a change detection task. Compared to a condition in which participants were simply told to do their best, we found that estimated capacity was increased for participants who were instructed to remember the entire visual display, even at set sizes beyond their capacity. However, no increase in estimated capacity was found for a group that was told to focus on a subset of the items in supracapacity arrays. This finding confirms the hypothesis that encoding strategies may influence visual working memory performance, and it is contrary to the hypothesis that the optimal strategy is to filter out any items beyond the storage capacity.

Social cohesiveness and absenteeism: The relationship between characteristics of employees and short-term absenteeism

NARCIS (Netherlands)

Sanders, Karin; Nauta, Aukje

2004-01-01

This study tries to explain the relationship between characteristics of the employees (e.g., gender and working hours) and short-term absenteeism by examining the social cohesiveness of a team. Hypotheses are formulated concerning gender and working hours of employees, social cohesiveness, and

The short-term impacts of Earned Income Tax Credit disbursement on health.

Science.gov (United States)

Rehkopf, David H; Strully, Kate W; Dow, William H

2014-12-01

There are conflicting findings regarding long- and short-term effects of income on health. Whereas higher average income is associated with better health, there is evidence that health behaviours worsen in the short-term following income receipt.Prior studies revealing such negative short-term effects of income receipt focus on specific subpopulations and examine a limited set of health outcomes. The United States Earned Income Tax Credit (EITC) is an income supplement tied to work, and is the largest poverty reduction programme in the USA. We utilize the fact that EITC recipients typically receive large cash transfers in the months of February,March and April, in order to examine associated changes in health outcomes that can fluctuate on a monthly basis. We examine associations with 30 outcomes in the categories of diet, food security, health behaviours, cardiovascular biomarkers, metabolic biomarkers and infection and immunity among 6925 individuals from the U.S. National Health and Nutrition Survey. Our research design approximates a natural experiment,since whether individuals were sampled during treatment or non-treatment months is independent of social, demographic and health characteristics that do not vary with time. There are both beneficial and detrimental short-term impacts of income receipt.Although there are detrimental impacts on metabolic factors among women, most other impacts are beneficial, including those for food security, smoking and trying to lose weight. The short-term impacts of EITC income receipt are not universally health promoting, but on balance there are more health benefits than detriments.

Circadian modulation of short-term memory in Drosophila.

Science.gov (United States)

Lyons, Lisa C; Roman, Gregg

2009-01-01

Endogenous biological clocks are widespread regulators of behavior and physiology, allowing for a more efficient allocation of efforts and resources over the course of a day. The extent that different processes are regulated by circadian oscillators, however, is not fully understood. We investigated the role of the circadian clock on short-term associative memory formation using a negatively reinforced olfactory-learning paradigm in Drosophila melanogaster. We found that memory formation was regulated in a circadian manner. The peak performance in short-term memory (STM) occurred during the early subjective night with a twofold performance amplitude after a single pairing of conditioned and unconditioned stimuli. This rhythm in memory is eliminated in both timeless and period mutants and is absent during constant light conditions. Circadian gating of sensory perception does not appear to underlie the rhythm in short-term memory as evidenced by the nonrhythmic shock avoidance and olfactory avoidance behaviors. Moreover, central brain oscillators appear to be responsible for the modulation as cryptochrome mutants, in which the antennal circadian oscillators are nonfunctional, demonstrate robust circadian rhythms in short-term memory. Together these data suggest that central, rather than peripheral, circadian oscillators modulate the formation of short-term associative memory and not the perception of the stimuli.

The generalizability of working-memory capacity in the sport domain.

Science.gov (United States)

Buszard, Tim; Masters, Rich Sw; Farrow, Damian

2017-08-01

Working-memory capacity has been implicated as an influential variable when performing and learning sport-related skills. In this review, we critically evaluate evidence linking working-memory capacity with performing under pressure, tactical decision making, motor skill acquisition, and sport expertise. Laboratory experiments link low working-memory capacity with poorer performance under pressure and poorer decision making when required to inhibit distractions or resolve conflict. However, the generalizability of these findings remains unknown. While working-memory capacity is associated with the acquisition of simple motor skills, there is no such evidence from the available data for complex motor skills. Likewise, currently there is no evidence to suggest that a larger working-memory capacity facilitates the attainment of sport expertise. Copyright © 2017 Elsevier Ltd. All rights reserved.

Semantic and phonological contributions to short-term repetition and long-term cued sentence recall.

Science.gov (United States)

Meltzer, Jed A; Rose, Nathan S; Deschamps, Tiffany; Leigh, Rosie C; Panamsky, Lilia; Silberberg, Alexandra; Madani, Noushin; Links, Kira A

2016-02-01

The function of verbal short-term memory is supported not only by the phonological loop, but also by semantic resources that may operate on both short and long time scales. Elucidation of the neural underpinnings of these mechanisms requires effective behavioral manipulations that can selectively engage them. We developed a novel cued sentence recall paradigm to assess the effects of two factors on sentence recall accuracy at short-term and long-term stages. Participants initially repeated auditory sentences immediately following a 14-s retention period. After this task was complete, long-term memory for each sentence was probed by a two-word recall cue. The sentences were either concrete (high imageability) or abstract (low imageability), and the initial 14-s retention period was filled with either an undemanding finger-tapping task or a more engaging articulatory suppression task (Exp. 1, counting backward by threes; Exp. 2, repeating a four-syllable nonword). Recall was always better for the concrete sentences. Articulatory suppression reduced accuracy in short-term recall, especially for abstract sentences, but the sentences initially recalled following articulatory suppression were retained better at the subsequent cued-recall test, suggesting that the engagement of semantic mechanisms for short-term retention promoted encoding of the sentence meaning into long-term memory. These results provide a basis for using sentence imageability and subsequent memory performance as probes of semantic engagement in short-term memory for sentences.

The case against specialized visual-spatial short-term memory.

Science.gov (United States)

Morey, Candice C

2018-05-24

The dominant paradigm for understanding working memory, or the combination of the perceptual, attentional, and mnemonic processes needed for thinking, subdivides short-term memory (STM) according to whether memoranda are encoded in aural-verbal or visual formats. This traditional dissociation has been supported by examples of neuropsychological patients who seem to selectively lack STM for either aural-verbal, visual, or spatial memoranda, and by experimental research using dual-task methods. Though this evidence is the foundation of assumptions of modular STM systems, the case it makes for a specialized visual STM system is surprisingly weak. I identify the key evidence supporting a distinct verbal STM system-patients with apparent selective damage to verbal STM and the resilience of verbal short-term memories to general dual-task interference-and apply these benchmarks to neuropsychological and experimental investigations of visual-spatial STM. Contrary to the evidence on verbal STM, patients with apparent visual or spatial STM deficits tend to experience a wide range of additional deficits, making it difficult to conclude that a distinct short-term store was damaged. Consistently with this, a meta-analysis of dual-task visual-spatial STM research shows that robust dual-task costs are consistently observed regardless of the domain or sensory code of the secondary task. Together, this evidence suggests that positing a specialized visual STM system is not necessary. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Short-term and long-term sick-leave in Sweden

DEFF Research Database (Denmark)

Blank, N; Diderichsen, Finn

1995-01-01

The primary aim of the study was to analyse similarities and differences between repeated spells of short-term sick-leave (more than 3 spells of less than 7 days' duration in a 12-month period) and long-term absence through sickness (at least 1 spell of more than 59 days' duration in a 12-month p...

Keeping it together: Semantic coherence stabilizes phonological sequences in short-term memory.

Science.gov (United States)

Savill, Nicola; Ellis, Rachel; Brooke, Emma; Koa, Tiffany; Ferguson, Suzie; Rojas-Rodriguez, Elena; Arnold, Dominic; Smallwood, Jonathan; Jefferies, Elizabeth

2018-04-01

Our ability to hold a sequence of speech sounds in mind, in the correct configuration, supports many aspects of communication, but the contribution of conceptual information to this basic phonological capacity remains controversial. Previous research has shown modest and inconsistent benefits of meaning on phonological stability in short-term memory, but these studies were based on sets of unrelated words. Using a novel design, we examined the immediate recall of sentence-like sequences with coherent meaning, alongside both standard word lists and mixed lists containing words and nonwords. We found, and replicated, substantial effects of coherent meaning on phoneme-level accuracy: The phonemes of both words and nonwords within conceptually coherent sequences were more likely to be produced together and in the correct order. Since nonwords do not exist as items in long-term memory, the semantic enhancement of phoneme-level recall for both item types cannot be explained by a lexically based item reconstruction process employed at the point of retrieval ("redintegration"). Instead, our data show, for naturalistic input, that when meaning emerges from the combination of words, the phonological traces that support language are reinforced by a semantic-binding process that has been largely overlooked by past short-term memory research.

Lexical Learning in Bilingual Adults: The Relative Importance of Short-Term Memory for Serial Order and Phonological Knowledge

Science.gov (United States)

Majerus, Steve; Poncelet, Martine; Van der Linden, Martial; Weekes, Brendan S.

2008-01-01

Studies of monolingual speakers have shown a strong association between lexical learning and short-term memory (STM) capacity, especially STM for serial order information. At the same time, studies of bilingual speakers suggest that phonological knowledge is the main factor that drives lexical learning. This study tested these two hypotheses…

Oil price shocks and their short- and long-term effects on the Chinese economy

International Nuclear Information System (INIS)

Tang, Weiqi; Wu, Libo; Zhang, ZhongXiang

2010-01-01

A considerable body of economic literature shows the adverse economic impacts of oil-price shocks for the developed economies. However, there has been a lack of similar empirical study on China and other developing countries. This paper attempts to fill this gap by answering how and to what extent oil-price shocks impact China's economy, emphasizing on the price transmission mechanisms. To that end, we develop a structural vector auto-regressive model. Our results show that an oil-price increase negatively affects output and investment, but positively affects inflation rate and interest rate. However, with price control policies in China, the impact on real economy, represented by real output and real investment, lasts much longer than that to price/monetary variables. Our decomposition results also show that the short-term impact, namely output decrease induced by the cut in capacity-utilization rate, is greater in the first 6 periods (namely half a year), but the portion of the long-term impact, defined as the impact realized through an investment change, increases steadily and exceeds that of short-term impact in the 7th period. Afterwards, the long-term impact dominates, and maintains for quite some time. (author)

ASSERT: Augmentation Grant on Working Memory Capacity

National Research Council Canada - National Science Library

Engle, Randall

2000-01-01

.... That work has resulted in numerous publications and conference presentations demonstrating that individuals who score in the bottom quartile on measures of working memory capacity show more errors...

Variation in Parasympathetic Dysregulation Moderates Short-term Memory Problems in Childhood Attention-Deficit/Hyperactivity Disorder.

Science.gov (United States)

Ward, Anthony R; Alarcón, Gabriela; Nigg, Joel T; Musser, Erica D

2015-11-01

Although attention deficit/hyperactivity disorder (ADHD) is associated with impairment in working memory and short-term memory, up to half of individual children with ADHD perform within a normative range. Heterogeneity in other ADHD-related mechanisms, which may compensate for or combine with cognitive weaknesses, is a likely explanation. One candidate is the robustness of parasympathetic regulation (as indexed by respiratory sinus arrhythmia; RSA). Theory and data suggest that a common neural network is likely tied to both heart-rate regulation and certain cognitive functions (including aspects of working and short-term memory). Cardiac-derived indices of parasympathetic reactivity were collected during short-term memory (STM) storage and rehearsal tasks from 243 children (116 ADHD, 127 controls). ADHD was associated with lower STM performance, replicating previous work. In addition, RSA reactivity moderated the association between STM and ADHD - both as a category and a dimension - independent of comorbidity. Specifically, conditional effects revealed that high levels of withdrawal interacted with weakened STM but high levels of augmentation moderated a positive association predicting ADHD. Thus, variations in parasympathetic reactivity may help explain neuropsychological heterogeneity in ADHD.

Overwriting and intrusion in short-term memory.

Science.gov (United States)

Bancroft, Tyler D; Jones, Jeffery A; Ensor, Tyler M; Hockley, William E; Servos, Philip

2016-04-01

Studies of interference in working and short-term memory suggest that irrelevant information may overwrite the contents of memory or intrude into memory. While some previous studies have reported greater interference when irrelevant information is similar to the contents of memory than when it is dissimilar, other studies have reported greater interference for dissimilar distractors than for similar distractors. In the present study, we find the latter effect in a paradigm that uses auditory tones as stimuli. We suggest that the effects of distractor similarity to memory contents are mediated by the type of information held in memory, particularly the complexity or simplicity of information.

Short-term Consumer Benefits of Dynamic Pricing

OpenAIRE

Dupont, Benjamin; De Jonghe, Cedric; Kessels, Kris; Belmans, Ronnie

2011-01-01

Consumer benefits of dynamic pricing depend on a variety of factors. Consumer characteristics and climatic circumstances widely differ, which forces a regional comparison. This paper presents a general overview of demand response programs and focuses on the short-term benefits of dynamic pricing for an average Flemish residential consumer. It reaches a methodology to develop a cost reflective dynamic pricing program and to estimate short-term bill savings. Participating in a dynamic pricing p...

Pile Load Capacity – Calculation Methods

Directory of Open Access Journals (Sweden)

Wrana Bogumił

2015-12-01

Full Text Available The article is a review of the current problems of the foundation pile capacity calculations. The article considers the main principles of pile capacity calculations presented in Eurocode 7 and other methods with adequate explanations. Two main methods are presented: α – method used to calculate the short-term load capacity of piles in cohesive soils and β – method used to calculate the long-term load capacity of piles in both cohesive and cohesionless soils. Moreover, methods based on cone CPTu result are presented as well as the pile capacity problem based on static tests.

Short-term memory and working memory in children with blindness: support for a domain general or domain specific system?

Science.gov (United States)

Swanson, H Lee; Luxenberg, Diana

2009-05-01

The study explored the contribution of two component processes (phonological and executive) to blind children's memory performance. Children with blindness and sight were matched on gender, chronological age, and verbal intelligence and compared on measures of short-term memory (STM) and working memory (WM). Although the measures were highly correlated, the results from two experiments indicated that the blind children were superior to sighted children on measures of STM, but not on measures of WM. The results supported the notion that children with blindness have advantages on memory tasks that draw upon resources from the phonological loop. However, comparable performance between the ability groups on WM measures suggests there are domain specific aspects in the executive system.

Short-term Automated Quantification of Radiologic Changes in the Characterization of Idiopathic Pulmonary Fibrosis Versus Nonspecific Interstitial Pneumonia and Prediction of Long-term Survival.

Science.gov (United States)

De Giacomi, Federica; Raghunath, Sushravya; Karwoski, Ronald; Bartholmai, Brian J; Moua, Teng

2018-03-01

Fibrotic interstitial lung diseases presenting with nonspecific and overlapping radiologic findings may be difficult to diagnose without surgical biopsy. We hypothesized that baseline quantifiable radiologic features and their short-term interval change may be predictive of underlying histologic diagnosis as well as long-term survival in idiopathic pulmonary fibrosis (IPF) presenting without honeycombing versus nonspecific interstitial pneumonia (NSIP). Forty biopsy-confirmed IPF and 20 biopsy-confirmed NSIP patients with available high-resolution chest computed tomography 4 to 24 months apart were studied. CALIPER software was used for the automated characterization and quantification of radiologic findings. IPF subjects were older (66 vs. 48; P<0.0001) with lower diffusion capacity for carbon monoxide and higher volumes of baseline reticulation (193 vs. 83 mL; P<0.0001). Over the interval period, compared with NSIP, IPF patients experienced greater functional decline (forced vital capacity, -6.3% vs. -1.7%; P=0.02) and radiologic progression, as noted by greater increase in reticulation volume (24 vs. 1.74 mL; P=0.048), and decrease in normal (-220 vs. -37.7 mL; P=0.045) and total lung volumes (-198 vs. 58.1 mL; P=0.03). Older age, male gender, higher reticulation volumes at baseline, and greater interval decrease in normal lung volumes were predictive of IPF. Both baseline and short-term changes in quantitative radiologic findings were predictive of mortality. Baseline quantitative radiologic findings and assessment of short-term disease progression may help characterize underlying IPF versus NSIP in those with difficult to differentiate clinicoradiologic presentations. Our study supports the possible utility of assessing serial quantifiable high-resolution chest computed tomographic findings for disease differentiation in these 2 entities.

Musical and Verbal Memory in Alzheimer's Disease: A Study of Long-Term and Short-Term Memory

Science.gov (United States)

Menard, Marie-Claude; Belleville, Sylvie

2009-01-01

Musical memory was tested in Alzheimer patients and in healthy older adults using long-term and short-term memory tasks. Long-term memory (LTM) was tested with a recognition procedure using unfamiliar melodies. Short-term memory (STM) was evaluated with same/different judgment tasks on short series of notes. Musical memory was compared to verbal…

A least squares approach for efficient and reliable short-term versus long-term optimization

DEFF Research Database (Denmark)

Christiansen, Lasse Hjuler; Capolei, Andrea; Jørgensen, John Bagterp

2017-01-01

The uncertainties related to long-term forecasts of oil prices impose significant financial risk on ventures of oil production. To minimize risk, oil companies are inclined to maximize profit over short-term horizons ranging from months to a few years. In contrast, conventional production...... optimization maximizes long-term profits over horizons that span more than a decade. To address this challenge, the oil literature has introduced short-term versus long-term optimization. Ideally, this problem is solved by a posteriori multi-objective optimization methods that generate an approximation...... the balance between the objectives, leaving an unfulfilled potential to increase profits. To promote efficient and reliable short-term versus long-term optimization, this paper introduces a natural way to characterize desirable Pareto points and proposes a novel least squares (LS) method. Unlike hierarchical...

A novel TRNSYS type for short-term borehole heat exchanger simulation: B2G model

International Nuclear Information System (INIS)

De Rosa, Mattia; Ruiz-Calvo, Félix; Corberán, José M.; Montagud, Carla; Tagliafico, Luca A.

2015-01-01

Highlights: • A novel dynamic borehole heat exchanger model is presented. • Theoretical approach for model parameters calculation is described. • The short-term model is validated against experimental data of a real GSHP. • Strong dynamic conditions due to the ON–OFF regulation are investigated. - Abstract: Models of ground source heat pump (GSHP) systems are used as an aid for the correct design and optimization of the system. For this purpose, it is necessary to develop models which correctly reproduce the dynamic thermal behavior of each component in a short-term basis. Since the borehole heat exchanger (BHE) is one of the main components, special attention should be paid to ensuring a good accuracy on the prediction of the short-term response of the boreholes. The BHE models found in literature which are suitable for short-term simulations usually present high computational costs. In this work, a novel TRNSYS type implementing a borehole-to-ground (B2G) model, developed for modeling the short-term dynamic performance of a BHE with low computational cost, is presented. The model has been validated against experimental data from a GSHP system located at Universitat Politècnica de València, Spain. Validation results show the ability of the model to reproduce the short-term behavior of the borehole, both for a step-test and under normal operating conditions

Margins for uncertainties in Hydro-Quebec's short-term operations planning

International Nuclear Information System (INIS)

Beaumont, M.; Raymond, M.P.

1995-01-01

A method developed by Hydro-Quebec for establishing the short-term capacity margin requirements for dealing with uncertainties from 1 to 24 hours in advance, was presented. Hydro-Quebec's generating system and characterization of the problems associated with meeting load requirements were discussed. Factors accounted for included those concerning internal load forecast, unit forced outages, risks of not meeting firm load, risks of not meeting real-time reserves requirements, costs, time delays, and operating constraints of non-hydraulic resources. Each of these were described in detail, and methods for combining mathematical uncertainties were presented. Procedures used for selecting an appropriate risk level and building a margin policy were described. Improvements for more accurate modelling were discussed. 5 refs., 2 tabs., 5 figs

Familiarity speeds up visual short-term memory consolidation.

Science.gov (United States)

Xie, Weizhen; Zhang, Weiwei

2017-06-01

Existing long-term memory (LTM) can boost the number of retained representations over a short delay in visual short-term memory (VSTM). However, it is unclear whether and how prior LTM affects the initial process of transforming fragile sensory inputs into durable VSTM representations (i.e., VSTM consolidation). The consolidation speed hypothesis predicts faster consolidation for familiar relative to unfamiliar stimuli. Alternatively, the perceptual boost hypothesis predicts that the advantage in perceptual processing of familiar stimuli should add a constant boost for familiar stimuli during VSTM consolidation. To test these competing hypotheses, the present study examined how the large variance in participants' prior multimedia experience with Pokémon affected VSTM for Pokémon. In Experiment 1, the amount of time allowed for VSTM consolidation was manipulated by presenting consolidation masks at different intervals after the onset of to-be-remembered Pokémon characters. First-generation Pokémon characters that participants were more familiar with were consolidated faster into VSTM as compared with recent-generation Pokémon characters that participants were less familiar with. These effects were absent in participants who were unfamiliar with both generations of Pokémon. Although familiarity also increased the number of retained Pokémon characters when consolidation was uninterrupted but still incomplete due to insufficient encoding time in Experiment 1, this capacity effect was absent in Experiment 2 when consolidation was allowed to complete with sufficient encoding time. Together, these results support the consolidation speed hypothesis over the perceptual boost hypothesis and highlight the importance of assessing experimental effects on both processing and representation aspects of VSTM. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Social evolution and genetic interactions in the short and long term.

Science.gov (United States)

Van Cleve, Jeremy

2015-08-01

capture both weak and strong effects of social payoffs in a manner difficult to replicate with the short-term approach. Together, the results from the short and long-term approaches suggest both how Hamilton's insight may be robust in unexpected ways and how current analytical approaches can expand our understanding of social evolution far beyond Hamilton's original work. Copyright © 2015 Elsevier Inc. All rights reserved.

Creativity and working memory capacity in sports: working memory capacity is not a limiting factor in creative decision making amongst skilled performers.

Science.gov (United States)

Furley, Philip; Memmert, Daniel

2015-01-01

The goal of the study was to investigate the relationship between domain-general working memory capacity and domain-specific creativity amongst experienced soccer players. We administered the automated operation span task in combination with a domain-specific soccer creativity task to a group of 61 experienced soccer players to address the question whether an athlete's domain-specific creativity is restricted by their domain-general cognitive abilities (i.e., working memory capacity). Given that previous studies have either found a positive correlation, a negative correlation, or no correlation between working memory capacity and creativity, we analyzed the data in an exploratory manner by following recent recommendations to report effect-size estimations and their precision in form of 95% confidence intervals. The pattern of results provided evidence that domain-general working memory capacity is not associated with creativity in a soccer-specific creativity task. This pattern of results suggests that future research and theorizing on the role of working memory in everyday creative performance needs to distinguish between different types of creative performance while also taking the role of domain-specific experience into account.

Working Memory Capacity and Fluid Intelligence: Maintenance and Disengagement.

Science.gov (United States)

Shipstead, Zach; Harrison, Tyler L; Engle, Randall W

2016-11-01

Working memory capacity and fluid intelligence have been demonstrated to be strongly correlated traits. Typically, high working memory capacity is believed to facilitate reasoning through accurate maintenance of relevant information. In this article, we present a proposal reframing this issue, such that tests of working memory capacity and fluid intelligence are seen as measuring complementary processes that facilitate complex cognition. Respectively, these are the ability to maintain access to critical information and the ability to disengage from or block outdated information. In the realm of problem solving, high working memory capacity allows a person to represent and maintain a problem accurately and stably, so that hypothesis testing can be conducted. However, as hypotheses are disproven or become untenable, disengaging from outdated problem solving attempts becomes important so that new hypotheses can be generated and tested. From this perspective, the strong correlation between working memory capacity and fluid intelligence is due not to one ability having a causal influence on the other but to separate attention-demanding mental functions that can be contrary to one another but are organized around top-down processing goals. © The Author(s) 2016.

Sleep Quality, Short-Term and Long-Term CPAP Adherence

Science.gov (United States)

Somiah, Manya; Taxin, Zachary; Keating, Joseph; Mooney, Anne M.; Norman, Robert G.; Rapoport, David M.; Ayappa, Indu

2012-01-01

Study Objectives: Adherence to CPAP therapy is low in patients with obstructive sleep apnea/hypopnea syndrome (OSAHS). The purpose of the present study was to evaluate the utility of measures of sleep architecture and sleep continuity on the CPAP titration study as predictors of both short- and long-term CPAP adherence. Methods: 93 patients with OSAHS (RDI 42.8 ± 34.3/h) underwent in-laboratory diagnostic polysomnography, CPAP titration, and follow-up polysomnography (NPSG) on CPAP. Adherence to CPAP was objectively monitored. Short-term (ST) CPAP adherence was averaged over 14 days immediately following the titration study. Long-term (LT) CPAP adherence was obtained in 56/93 patients after approximately 2 months of CPAP use. Patients were grouped into CPAP adherence groups for ST ( 4 h) and LT adherence ( 4 h). Sleep architecture, sleep disordered breathing (SDB) indices, and daytime outcome variables from the diagnostic and titration NPSGs were compared between CPAP adherence groups. Results: There was a significant relationship between ST and LT CPAP adherence (r = 0.81, p CPAP adherence groups had significantly lower %N2 and greater %REM on the titration NPSG. A model combining change in sleep efficiency and change in sleep continuity between the diagnostic and titration NPSGs predicted 17% of the variance in LT adherence (p = 0.006). Conclusions: These findings demonstrate that characteristics of sleep architecture, even on the titration NPSG, may predict some of the variance in CPAP adherence. Better sleep quality on the titration night was related to better CPAP adherence, suggesting that interventions to improve sleep on/prior to the CPAP titration study might be used as a therapeutic intervention to improve CPAP adherence. Citation: Somiah M; Taxin Z; Keating J; Mooney AM; Norman RG; Rapoport DM; Ayappa I. Sleep quality, short-term and long-term CPAP adherence. J Clin Sleep Med 2012;8(5):489-500. PMID:23066359

Psychological Peculiarities of Teachers with Different Work Capacity Levels

Directory of Open Access Journals (Sweden)

O. I. Dorogina

2012-01-01

Full Text Available The paper considers the issue of teacher’s work capacity optimization. The research is aimed at defining teachers’ psychological peculiarities relating to their work capacity level and creating the assistance program for its optimization. In the course of the program implementation, its effectiveness has being proved, the low work capacity being optimized by developing self-control, emotional stability and decreasing the aggressive reactions in frustrating situations. The research findings can be applied while creating programs for teachers’ further training as well as for students training courses. 

Short Term Airing by Natural Ventilation

DEFF Research Database (Denmark)

Heiselberg, Per; Perino, M.

2010-01-01

The need to improve the energy efficiency of buildings requires new and more efficient ventilation systems. It has been demonstrated that innovative operating concepts that make use of natural ventilation seem to be more appreciated by occupants. Among the available ventilation strategies...... that are currently available, buoyancy driven, single-sided natural ventilation has proved to be very effective and can provide high air change rates for temperature and Indoor Air Quality (IAQ) control. However, to promote a wider distribution of these systems an improvement in the knowledge of their working...... airflow rate, ventilation efficiency, thermal comfort and dynamic temperature conditions. A suitable laboratory test rig was developed to perform extensive experimental analyses of the phenomenon under controlled and repeatable conditions. The results showed that short-term window airing is very effective...

Weighted integration of short-term memory and sensory signals in the oculomotor system.

Science.gov (United States)

Deravet, Nicolas; Blohm, Gunnar; de Xivry, Jean-Jacques Orban; Lefèvre, Philippe

2018-05-01

Oculomotor behaviors integrate sensory and prior information to overcome sensory-motor delays and noise. After much debate about this process, reliability-based integration has recently been proposed and several models of smooth pursuit now include recurrent Bayesian integration or Kalman filtering. However, there is a lack of behavioral evidence in humans supporting these theoretical predictions. Here, we independently manipulated the reliability of visual and prior information in a smooth pursuit task. Our results show that both smooth pursuit eye velocity and catch-up saccade amplitude were modulated by visual and prior information reliability. We interpret these findings as the continuous reliability-based integration of a short-term memory of target motion with visual information, which support modeling work. Furthermore, we suggest that saccadic and pursuit systems share this short-term memory. We propose that this short-term memory of target motion is quickly built and continuously updated, and constitutes a general building block present in all sensorimotor systems.

Goal-neglect links Stroop interference with working memory capacity

NARCIS (Netherlands)

Morey, C.C.; Elliott, E.M.; Wiggers, J.; Eaves, S.L.; Shelton, J.T.; Mall, Jonathan

2012-01-01

Relationships between Stroop interference and working memory capacity may reflect individual differences in resolving conflict, susceptibility to goal neglect, or both of these factors. We compared relationships between working memory capacity and three Stroop tasks: a classic, printed color-word

Stability analysis of roadway embankments supported by stone columns with the presence of water table under short-term and long-term conditions

Directory of Open Access Journals (Sweden)

Kadhim Shaymaa Tareq

2018-01-01

Full Text Available Use of stone column technique to improve soft foundation soils under roadway embankments has proven to increase the bearing capacity and reduce the potential settlement. The potential contribution of stone columns to the stability of roadway embankments against general (i.e. deep-seated failure needs to be thoroughly investigated. Therefore, a two-dimensional finite difference model implemented by FLAC/SLOPE 7.0 software, was employed in this study to assess the stability of a roadway embankment fill built on a soft soil deposit improved by stone column technique. The stability factor of safety was obtained numerically under both short-term and long-term conditions with the presence of water table. Two methods were adopted to convert the three-dimensional model into plane strain condition: column wall and equivalent improved ground methods. The effect of various parameters was studied to evaluate their influence on the factor of safety against embankment instability. For instance, the column diameter, columns’ spacing, soft soil properties for short-term and long-term conditions, and the height and friction angle of the embankment fill. The results of this study are developed in several design charts.

The pedagogy of Short-Term Study-Abroad Programs

Directory of Open Access Journals (Sweden)

Jude Gonsalvez

2013-10-01

Full Text Available This paper focuses on establishing guidelines on the pedagogy of short term study abroad programs. This study follows 33 students who participated in a short-term study-abroad program to India with the researcher from 2006 through 2011. The study relies heavily on the student reflections and expressions as they experienced them. It is qualitative in nature. Focus groups were the main method of data collection, where participants were invited to reflect, express, and share their experiences with one another. This provided an opportunity for the participants to come together, relive their experiences, and help provide information as to how and what type of an influence this short-term study-abroad program provided.

Verbal Short-Term Memory Shows a Specific Association with Receptive but Not Productive Vocabulary Measures in Down Syndrome

Science.gov (United States)

Majerus, S.; Barisnikov, K.

2018-01-01

Background: Verbal short-term memory (STM) capacity has been considered to support vocabulary learning in typical children and adults, but evidence for this link is inconsistent for studies in individuals with Down syndrome (DS). The aim of this study was explore the role of processing demands on the association between verbal STM and vocabulary…

Forest Growth Responses to Drought at Short- and Long-Term Scales in Spain: Squeezing the Stress Memory from Tree Rings

Directory of Open Access Journals (Sweden)

J. Julio Camarero

2018-02-01

Full Text Available Drought-triggered declines in forest productivity and associated die-off events have increased considerably due to climate warming in the last decades. There is an increasing interest in quantifying the resilience capacity of forests against climate warming and drought to uncover how different stands and tree species will resist and recover after more frequent and intense droughts. Trees form annual growth rings that represent an accurate record of how forest growth responded to past droughts. Here we use dendrochronology to quantify the radial growth of different forests subjected to contrasting climatic conditions in Spain during the last half century. Particularly, we considered four climatically contrasting areas where dominant forests showed clear signs of drought-induced dieback. Studied forests included wet sites dominated by silver fir (Abies alba in the Pyrenees and beech (Fagus sylvatica stands in northern Spain, and drought-prone sites dominated by Scots pine (Pinus sylvestris in eastern Spain and black pine (Pinus nigra in the semi-arid south-eastern Spain. We quantified the growth reduction caused by different droughts and assessed the short-and long-term resilience capacity of declining vs. non-declining trees in each forest. In all cases, drought induced a marked growth reduction regardless tree vigor. However, the capacity to recover after drought (resilience at short- and long-term scales varied greatly between declining and non-declining individuals. In the case of beech and silver fir, non-declining individuals presented greater growth rates and capacity to recover after drought than declining individuals. For Scots pine, the resilience to drought was found to be lower in recent years regardless the tree vigor, but the growth reduction caused by successive droughts was more pronounced in declining than in non-declining individuals. In the black pine forest an extreme drought induced a marked growth reduction in declining

Building adaptive capacity in Assam

Directory of Open Access Journals (Sweden)

Soumyadeep Banerjee

2015-05-01

Full Text Available A starting point for adapting to longer-term climate change could be adaptation to short-term climate variability and extreme events. Making more informed choices about the use of remittances can enhance the adaptive capacity of remittance-receiving households.

Working memory capacity and the spacing effect in cued recall.

Science.gov (United States)

Delaney, Peter F; Godbole, Namrata R; Holden, Latasha R; Chang, Yoojin

2018-07-01

Spacing repetitions typically improves memory (the spacing effect). In three cued recall experiments, we explored the relationship between working memory capacity and the spacing effect. People with higher working memory capacity are more accurate on memory tasks that require retrieval relative to people with lower working memory capacity. The experiments used different retention intervals and lags between repetitions, but were otherwise similar. Working memory capacity and spacing of repetitions both improved memory in most of conditions, but they did not interact, suggesting additive effects. The results are consistent with the ACT-R model's predictions, and with a study-phase recognition process underpinning the spacing effect in cued recall.

Genetic deletion of melanin-concentrating hormone neurons impairs hippocampal short-term synaptic plasticity and hippocampal-dependent forms of short-term memory.

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Le Barillier, Léa; Léger, Lucienne; Luppi, Pierre-Hervé; Fort, Patrice; Malleret, Gaël; Salin, Paul-Antoine

2015-11-01

The cognitive role of melanin-concentrating hormone (MCH) neurons, a neuronal population located in the mammalian postero-lateral hypothalamus sending projections to all cortical areas, remains poorly understood. Mainly activated during paradoxical sleep (PS), MCH neurons have been implicated in sleep regulation. The genetic deletion of the only known MCH receptor in rodent leads to an impairment of hippocampal dependent forms of memory and to an alteration of hippocampal long-term synaptic plasticity. By using MCH/ataxin3 mice, a genetic model characterized by a selective deletion of MCH neurons in the adult, we investigated the role of MCH neurons in hippocampal synaptic plasticity and hippocampal-dependent forms of memory. MCH/ataxin3 mice exhibited a deficit in the early part of both long-term potentiation and depression in the CA1 area of the hippocampus. Post-tetanic potentiation (PTP) was diminished while synaptic depression induced by repetitive stimulation was enhanced suggesting an alteration of pre-synaptic forms of short-term plasticity in these mice. Behaviorally, MCH/ataxin3 mice spent more time and showed a higher level of hesitation as compared to their controls in performing a short-term memory T-maze task, displayed retardation in acquiring a reference memory task in a Morris water maze, and showed a habituation deficit in an open field task. Deletion of MCH neurons could thus alter spatial short-term memory by impairing short-term plasticity in the hippocampus. Altogether, these findings could provide a cellular mechanism by which PS may facilitate memory encoding. Via MCH neuron activation, PS could prepare the day's learning by increasing and modulating short-term synaptic plasticity in the hippocampus. © 2015 Wiley Periodicals, Inc.

Folk music style modelling by recurrent neural networks with long short term memory units

OpenAIRE

Sturm, Bob; Santos, João Felipe; Korshunova, Iryna

2015-01-01

We demonstrate two generative models created by training a recurrent neural network (RNN) with three hidden layers of long short-term memory (LSTM) units. This extends past work in numerous directions, including training deeper models with nearly 24,000 high-level transcriptions of folk tunes. We discuss our on-going work.

Robust short-term memory without synaptic learning.

Directory of Open Access Journals (Sweden)

Samuel Johnson

Full Text Available Short-term memory in the brain cannot in general be explained the way long-term memory can--as a gradual modification of synaptic weights--since it takes place too quickly. Theories based on some form of cellular bistability, however, do not seem able to account for the fact that noisy neurons can collectively store information in a robust manner. We show how a sufficiently clustered network of simple model neurons can be instantly induced into metastable states capable of retaining information for a short time (a few seconds. The mechanism is robust to different network topologies and kinds of neural model. This could constitute a viable means available to the brain for sensory and/or short-term memory with no need of synaptic learning. Relevant phenomena described by neurobiology and psychology, such as local synchronization of synaptic inputs and power-law statistics of forgetting avalanches, emerge naturally from this mechanism, and we suggest possible experiments to test its viability in more biological settings.

Robust short-term memory without synaptic learning.

Science.gov (United States)

Johnson, Samuel; Marro, J; Torres, Joaquín J

2013-01-01

Short-term memory in the brain cannot in general be explained the way long-term memory can--as a gradual modification of synaptic weights--since it takes place too quickly. Theories based on some form of cellular bistability, however, do not seem able to account for the fact that noisy neurons can collectively store information in a robust manner. We show how a sufficiently clustered network of simple model neurons can be instantly induced into metastable states capable of retaining information for a short time (a few seconds). The mechanism is robust to different network topologies and kinds of neural model. This could constitute a viable means available to the brain for sensory and/or short-term memory with no need of synaptic learning. Relevant phenomena described by neurobiology and psychology, such as local synchronization of synaptic inputs and power-law statistics of forgetting avalanches, emerge naturally from this mechanism, and we suggest possible experiments to test its viability in more biological settings.

Robust Short-Term Memory without Synaptic Learning

Science.gov (United States)

Johnson, Samuel; Marro, J.; Torres, Joaquín J.

2013-01-01

Short-term memory in the brain cannot in general be explained the way long-term memory can – as a gradual modification of synaptic weights – since it takes place too quickly. Theories based on some form of cellular bistability, however, do not seem able to account for the fact that noisy neurons can collectively store information in a robust manner. We show how a sufficiently clustered network of simple model neurons can be instantly induced into metastable states capable of retaining information for a short time (a few seconds). The mechanism is robust to different network topologies and kinds of neural model. This could constitute a viable means available to the brain for sensory and/or short-term memory with no need of synaptic learning. Relevant phenomena described by neurobiology and psychology, such as local synchronization of synaptic inputs and power-law statistics of forgetting avalanches, emerge naturally from this mechanism, and we suggest possible experiments to test its viability in more biological settings. PMID:23349664

The relationship between sustained inattentional blindness and working memory capacity.

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Beanland, Vanessa; Chan, Esther Hiu Chung

2016-04-01

Inattentional blindness, whereby observers fail to detect unexpected stimuli, has been robustly demonstrated in a range of situations. Originally research focused primarily on how stimulus characteristics and task demands affect inattentional blindness, but increasingly studies are exploring the influence of observer characteristics on the detection of unexpected stimuli. It has been proposed that individual differences in working memory capacity predict inattentional blindness, on the assumption that higher working memory capacity confers greater attentional capacity for processing unexpected stimuli. Unfortunately, empirical investigations of the association between inattentional blindness and working memory capacity have produced conflicting findings. To help clarify this relationship, we examined the relationship between inattentional blindness and working memory capacity in two samples (Ns = 195, 147) of young adults. We used three common variants of sustained inattentional blindness tasks, systematically manipulating the salience of the unexpected stimulus and primary task practice. Working memory capacity, measured by automated operation span (both Experiments 1 & 2) and N-back (Experiment 1 only) tasks, did not predict detection of the unexpected stimulus in any of the inattentional blindness tasks tested. Together with previous research, this undermines claims that there is a robust relationship between inattentional blindness and working memory capacity. Rather, it appears that any relationship between inattentional blindness and working memory is either too small to have practical significance or is moderated by other factors and consequently varies with attributes such as the sample characteristics within a given study.

Calibration of short rate term structure models from bid-ask coupon bond prices

Science.gov (United States)

Gomes-Gonçalves, Erika; Gzyl, Henryk; Mayoral, Silvia

2018-02-01

In this work we use the method of maximum entropy in the mean to provide a model free, non-parametric methodology that uses only market data to provide the prices of the zero coupon bonds, and then, a term structure of the short rates. The data used consists of the prices of the bid-ask ranges of a few coupon bonds quoted in the market. The prices of the zero coupon bonds obtained in the first stage, are then used as input to solve a recursive set of equations to determine a binomial recombinant model of the short term structure of the interest rates.

A psychometric measure of working memory capacity for configured body movement.

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Ying Choon Wu

Full Text Available Working memory (WM models have traditionally assumed at least two domain-specific storage systems for verbal and visuo-spatial information. We review data that suggest the existence of an additional slave system devoted to the temporary storage of body movements, and present a novel instrument for its assessment: the movement span task. The movement span task assesses individuals' ability to remember and reproduce meaningless configurations of the body. During the encoding phase of a trial, participants watch short videos of meaningless movements presented in sets varying in size from one to five items. Immediately after encoding, they are prompted to reenact as many items as possible. The movement span task was administered to 90 participants along with standard tests of verbal WM, visuo-spatial WM, and a gesture classification test in which participants judged whether a speaker's gestures were congruent or incongruent with his accompanying speech. Performance on the gesture classification task was not related to standard measures of verbal or visuo-spatial working memory capacity, but was predicted by scores on the movement span task. Results suggest the movement span task can serve as an assessment of individual differences in WM capacity for body-centric information.

Intensive video gaming improves encoding speed to visual short-term memory in young male adults.

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Wilms, Inge L; Petersen, Anders; Vangkilde, Signe

2013-01-01

The purpose of this study was to measure the effect of action video gaming on central elements of visual attention using Bundesen's (1990) Theory of Visual Attention. To examine the cognitive impact of action video gaming, we tested basic functions of visual attention in 42 young male adults. Participants were divided into three groups depending on the amount of time spent playing action video games: non-players (15h/month, N=20). All participants were tested in three tasks which tap central functions of visual attention and short-term memory: a test based on the Theory of Visual Attention (TVA), an enumeration test and finally the Attentional Network Test (ANT). The results show that action video gaming does not seem to impact the capacity of visual short-term memory. However, playing action video games does seem to improve the encoding speed of visual information into visual short-term memory and the improvement does seem to depend on the time devoted to gaming. This suggests that intense action video gaming improves basic attentional functioning and that this improvement generalizes into other activities. The implications of these findings for cognitive rehabilitation training are discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

Slave systems in verbal short-term memory.

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Caplan, David; Waters, Gloria; Howard, David

2012-01-01

The model of performance in short-term memory (STM) tasks that has been most influential in cognitive neuropsychological work on deficits of STM is the "working memory" model mainly associated with the work of Alan Baddeley and his colleagues. This paper reviews the model. We examine the development of this theory in studies that account for STM performances in normal (non-brain-damaged) individuals, and then review the application of this theory to neuropsychological cases and specifications, modifications, and extensions of the theory that have been suggested on the basis of these cases. Our approach is to identify the major phenomena that have been discussed and to examine selected papers dealing with those phenomena in some detail. The main contribution is a review of the WM model that includes both normative and neuropsychological data. We conclude that the WM model has many inconsistencies and empirical inadequacies, and that cognitive neuropsychologists might benefit from considering other models when they attempt to describe and explain patients' performances on STM tasks.

Slave systems in verbal short-term memory

Science.gov (United States)

Caplan, David; Waters, Gloria; Howard, David

2013-01-01

Background The model of performance in short-term memory (STM) tasks that has been most influential in cognitive neuropsychological work on deficits of STM is the “working memory” model mainly associated with the work of Alan Baddeley and his colleagues. Aim This paper reviews the model. We examine the development of this theory in studies that account for STM performances in normal (non-brain-damaged) individuals, and then review the application of this theory to neuropsychological cases and specifications, modifications, and extensions of the theory that have been suggested on the basis of these cases. Our approach is to identify the major phenomena that have been discussed and to examine selected papers dealing with those phenomena in some detail. Main Contribution The main contribution is a review of the WM model that includes both normative and neuropsychological data. Conclusions We conclude that the WM model has many inconsistencies and empirical inadequacies, and that cognitive neuropsychologists might benefit from considering other models when they attempt to describe and explain patients’ performances on STM tasks. PMID:24347786

Short-term memory binding deficits in Alzheimer's disease

OpenAIRE

Parra, Mario; Abrahams, S.; Fabi, K.; Logie, R.; Luzzi, S.; Della Sala, Sergio

2009-01-01

Alzheimer's disease impairs long term memories for related events (e.g. faces with names) more than for single events (e.g. list of faces or names). Whether or not this associative or ‘binding’ deficit is also found in short-term memory has not yet been explored. In two experiments we investigated binding deficits in verbal short-term memory in Alzheimer's disease. Experiment 1 : 23 patients with Alzheimer's disease and 23 age and education matched healthy elderly were recruited. Participants...

Relationship between short-term sexual strategies and sexual jealousy.

Science.gov (United States)

Mathes, Eugene W

2005-02-01

In a classic study, Buss, Larson, Westen, and Semmelroth reported that men were more distressed by the thought of a partner's sexual infidelity (sexual jealousy) and women were more distressed by the thought of a partner's emotional infidelity (emotional jealousy). Initially, Buss and his associates explained these results by suggesting that men are concerned about uncertainty of paternity, that is, the possibility of raising another man's child while believing the child is their own. However, later they explained the results in terms of men's preference for short-term sexual strategies. The purpose of this research was to test the explanation of short-term sexual strategies. Men and women subjects were instructed to imagine themselves in a relationship which was either short-term (primarily sexual) or long-term (involving commitment) and then respond to Buss's jealousy items. It was hypothesized that, when both men and women imagined a short-term relationship, they would be more threatened by a partner's sexual infidelity, and, when they imagined a long-term relationship, they would be more threatened by a partner's emotional infidelity. Support was found for this hypothesis.

Dopamine Modulation of Reunion Behavior in Short and Long Term Marmoset Pairs

Directory of Open Access Journals (Sweden)

Sarah B. Carp

2018-05-01

rodents and primates, with the D1 system modulating the expression of behavior in long term pairs and the D2 system regulating behavior in short term pairs. Furthermore, these results supplement a large body of work suggestive of deep evolutionary roots of the DA system in regulating social behavior.

Model documentation report: Short-Term Hydroelectric Generation Model

International Nuclear Information System (INIS)

1993-08-01

The purpose of this report is to define the objectives of the Short- Term Hydroelectric Generation Model (STHGM), describe its basic approach, and to provide details on the model structure. This report is intended as a reference document for model analysts, users, and the general public. Documentation of the model is in accordance with the Energy Information Administration's (AYE) legal obligation to provide adequate documentation in support of its models (Public Law 94-385, Section 57.b.2). The STHGM performs a short-term (18 to 27- month) forecast of hydroelectric generation in the United States using an autoregressive integrated moving average (UREMIA) time series model with precipitation as an explanatory variable. The model results are used as input for the short-term Energy Outlook

Capacity planning and management

OpenAIRE

Boydell, Briony

2011-01-01

After reading this chapter you should be able to: • Define and measure capacity and appreciate the factors that influence it. • Assess the difficulties of matching capacity to demand. • Evaluate and apply the different strategies for matching capacity with demand in the short, medium and long term. • Analyse the impact of constraints and bottlenecks on a process and consider the Theory of Constraints. • Outline the different strategies available for both manufacturing and service operations. ...

Infant auditory short-term memory for non-linguistic sounds.

Science.gov (United States)

Ross-Sheehy, Shannon; Newman, Rochelle S

2015-04-01

This research explores auditory short-term memory (STM) capacity for non-linguistic sounds in 10-month-old infants. Infants were presented with auditory streams composed of repeating sequences of either 2 or 4 unique instruments (e.g., flute, piano, cello; 350 or 700 ms in duration) followed by a 500-ms retention interval. These instrument sequences either stayed the same for every repetition (Constant) or changed by 1 instrument per sequence (Varying). Using the head-turn preference procedure, infant listening durations were recorded for each stream type (2- or 4-instrument sequences composed of 350- or 700-ms notes). Preference for the Varying stream was taken as evidence of auditory STM because detection of the novel instrument required memory for all of the instruments in a given sequence. Results demonstrate that infants listened longer to Varying streams for 2-instrument sequences, but not 4-instrument sequences, composed of 350-ms notes (Experiment 1), although this effect did not hold when note durations were increased to 700 ms (Experiment 2). Experiment 3 replicates and extends results from Experiments 1 and 2 and provides support for a duration account of capacity limits in infant auditory STM. Copyright © 2014 Elsevier Inc. All rights reserved.

Impact of Spatial and Verbal Short-Term Memory Load on Auditory Spatial Attention Gradients.

Science.gov (United States)

Golob, Edward J; Winston, Jenna; Mock, Jeffrey R

2017-01-01

Short-term memory load can impair attentional control, but prior work shows that the extent of the effect ranges from being very general to very specific. One factor for the mixed results may be reliance on point estimates of memory load effects on attention. Here we used auditory attention gradients as an analog measure to map-out the impact of short-term memory load over space. Verbal or spatial information was maintained during an auditory spatial attention task and compared to no-load. Stimuli were presented from five virtual locations in the frontal azimuth plane, and subjects focused on the midline. Reaction times progressively increased for lateral stimuli, indicating an attention gradient. Spatial load further slowed responses at lateral locations, particularly in the left hemispace, but had little effect at midline. Verbal memory load had no (Experiment 1), or a minimal (Experiment 2) influence on reaction times. Spatial and verbal load increased switch costs between memory encoding and attention tasks relative to the no load condition. The findings show that short-term memory influences the distribution of auditory attention over space; and that the specific pattern depends on the type of information in short-term memory.

Impact of Spatial and Verbal Short-Term Memory Load on Auditory Spatial Attention Gradients

Directory of Open Access Journals (Sweden)

Edward J. Golob

2017-11-01

Full Text Available Short-term memory load can impair attentional control, but prior work shows that the extent of the effect ranges from being very general to very specific. One factor for the mixed results may be reliance on point estimates of memory load effects on attention. Here we used auditory attention gradients as an analog measure to map-out the impact of short-term memory load over space. Verbal or spatial information was maintained during an auditory spatial attention task and compared to no-load. Stimuli were presented from five virtual locations in the frontal azimuth plane, and subjects focused on the midline. Reaction times progressively increased for lateral stimuli, indicating an attention gradient. Spatial load further slowed responses at lateral locations, particularly in the left hemispace, but had little effect at midline. Verbal memory load had no (Experiment 1, or a minimal (Experiment 2 influence on reaction times. Spatial and verbal load increased switch costs between memory encoding and attention tasks relative to the no load condition. The findings show that short-term memory influences the distribution of auditory attention over space; and that the specific pattern depends on the type of information in short-term memory.

Letter in reference to: "Short-term effects of night shift work on breast cancer risk: a cohort study of payroll data".

Science.gov (United States)

Stevens, Richard G

2017-01-01

There are major flaws with the analyses in the Vistisen et al (1) cohort study examining if night shift work is a short-term risk factor for breast cancer. The crucial problem is the potential for exposure misclassification, which is very high. The authors' definition of day shift is "≥3 hours of work between 06:00-20:00 hours". This means that a worker on an 8-hour shift that begins at 03:00 hours would be classified as a day rather than night shift worker because he/she worked only two hours between 24:00-05:00 hours. Similarly, a second shifter might start work at 17:00 but not get off until 01:00 and yet still be classified as a "day shift" worker. This does not make sense as a baseline comparison group "unexposed" to work during the night hours. A sensible classification system would be to define "day shift" as any shift that begins after 07:00 and ends before 18:00 hours. This is straightforward and avoids all of the ambiguities inherent in the definition used by the authors. In addition, the authors claim that the "inception population" is less likely to have had past prior non-day work hours. However, this group has an average age of >35 years. It is inconceivable that all of these women were new graduates who started a public health sector job for the first time. Rather, the majority must surely have worked elsewhere for many years but then started in the regions covered only after 2006. This topic is too important, and this cohort too valuable, not to carefully define the baseline comparison group of "day workers" in a sensible manner. All the inferences rely crucially on this definition. The authors have the data to define the day-working baseline group in a way that avoids these obvious biases. That is why it is so frustrating that the authors chose to conduct the analyses as they did, with a highly flawed definition of "day work", when they could have done so much better. A highly flawed epidemiological report is worse than no report at all because

Looking good but doing harm? Perceptions of short-term medical missions in Nicaragua.

Science.gov (United States)

Nouvet, Elysée; Chan, Elizabeth; Schwartz, Lisa J

2018-04-01