Communication Games Reveal Preparation Contextuality

NASA Astrophysics Data System (ADS)

Hameedi, Alley; Tavakoli, Armin; Marques, Breno; Bourennane, Mohamed

2017-12-01

A communication game consists of distributed parties attempting to jointly complete a task with restricted communication. Such games are useful tools for studying limitations of physical theories. A theory exhibits preparation contextuality whenever its predictions cannot be explained by a preparation noncontextual model. Here, we show that communication games performed in operational theories reveal the preparation contextuality of that theory. For statistics obtained in a particular family of communication games, we show a direct correspondence with correlations in spacelike separated events obeying the no-signaling principle. Using this, we prove that all mixed quantum states of any finite dimension are preparation contextual. We report on an experimental realization of a communication game involving three-level quantum systems from which we observe a strong violation of the constraints of preparation noncontextuality.

1. West portal of Tunnel 1, contextual view to north, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. West portal of Tunnel 1, contextual view to north, 135mm lens. The Central Pacific originally built Tunnel 1 in 1868; Southern Pacific widened it in 1913 to accommodate both the original and new mainline as it continued its double-tracking efforts east from Colfax to Blue CaÏon. - Central Pacific Transcontinental Railroad, Tunnel No. 1, Milepost 164.34, Blue Canyon, Placer County, CA

Inhibition of Rac1 Activity in the Hippocampus Impairs the Forgetting of Contextual Fear Memory.

PubMed

Jiang, Lizhu; Mao, Rongrong; Zhou, Qixin; Yang, Yuexiong; Cao, Jun; Ding, Yuqiang; Yang, Yuan; Zhang, Xia; Li, Lingjiang; Xu, Lin

2016-03-01

Fear is crucial for survival, whereas hypermnesia of fear can be detrimental. Inhibition of the Rac GTPase is recently reported to impair the forgetting of initially acquired memory in Drosophila. Here, we investigated whether inhibition of Rac1 activity in rat hippocampus could contribute to the hypermnesia of contextual fear. We found that spaced but not massed training of contextual fear conditioning caused inhibition of Rac1 activity in the hippocampus and heightened contextual fear. Furthermore, intrahippocampal injection of the Rac1 inhibitor NSC23766 heightened contextual fear in massed training, while Rac1 activator CN04-A weakened contextual fear in spaced training rats. Our study firstly demonstrates that contextual fear memory in rats is actively regulated by Rac1 activity in the hippocampus, which suggests that the forgetting impairment of traumatic events in posttraumatic stress disorder may be contributed to the pathological inhibition of Rac1 activity in the hippocampus.

Contextual and social influences on valuation and choice.

PubMed

Engelmann, Jan B; Hein, Grit

2013-01-01

To survive in our complex environment, we have to adapt to changing contexts. Prior research that investigated how contextual changes are processed in the human brain has demonstrated important modulatory influences on multiple cognitive processes underlying decision-making, including perceptual judgments, working memory, as well as cognitive and attentional control. However, in everyday life, the importance of context is even more obvious during economic and social interactions, which often have implicit rule sets that need to be recognized by a decision-maker. Here, we review recent evidence from an increasing number of studies in the fields of Neuroeconomics and Social Neuroscience that investigate the neurobiological basis of contextual effects on valuation and social choice. Contrary to the assumptions of rational choice theory, multiple contextual factors, such as the availability of alternative choice options, shifts in reference point, and social context, have been shown to modulate behavior, as well as signals in task-relevant neural networks. A consistent picture that emerges from neurobiological results is that valuation-related activity in striatum and ventromedial prefrontal cortex is highly context dependent during both social and nonsocial choice. Alternative approaches to model and explain choice behavior, such as comparison-based choice models, as well as implications for future research are discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

Cultural and Contextual Influences on Parenting in Mexican American Families

ERIC Educational Resources Information Center

White, Rebecca M. B.; Roosa, Mark W.; Weaver, Scott R.; Nair, Rajni L.

2009-01-01

Family stress theory can explain associations between contextual stressors and parenting. The theory, however, has not been tested among Mexican Americans or expanded to include cultural-contextual risks. This study examined associations between neighborhood, economic, and acculturative stressors and parenting behaviors in a sample of 570…

Secondary Students' Stable and Unstable Optics Conceptions Using Contextualized Questions

ERIC Educational Resources Information Center

Chu, Hye-Eun; Treagust, David F.

2014-01-01

This study focuses on elucidating and explaining reasons for the stability of and interrelationships between students' conceptions about "Light Propagation" and "Visibility of Objects" using contextualized questions across 3 years of secondary schooling from Years 7 to 9. In a large-scale quantitative study involving 1,233…

Type 1 Adenylyl Cyclase is Essential for Maintenance of Remote Contextual Fear Memory

PubMed Central

Shan, Qiang; Chan, Guy C.-K.; Storm, Daniel R.

2008-01-01

Although molecular mechanisms for hippocampus-dependent memory have been extensively studied, much less is known about signaling events important for remote memory. Here we report that mice lacking type 1 adenylyl cyclase (AC1) are able to establish and retrieve remote contextual memory but unable to sustain it as long as wild type mice. Interestingly, mice over-expressing AC1 show superior remote contextual memory even though they exhibit normal hippocampus-dependent contextual memory. These data illustrate that calcium coupling to cAMP contributes to the stability of remote memory and identifies AC1 as a potential drug target site to improve long-term remote memory. PMID:19036980

The Influence of Contextual and Psychosocial Factors on Handwashing.

PubMed

Seimetz, Elisabeth; Boyayo, Anne-Marie; Mosler, Hans-Joachim

2016-06-01

Even though washing hands with soap is among the most effective measures to reduce the risk of infection, handwashing rates in infrastructure-restricted settings remain seriously low. Little is known about how context alone and in interaction with psychosocial factors influence hand hygiene behavior. The aim of this article was to explore how both contextual and psychosocial factors affect handwashing practices. A cross-sectional survey was conducted with 660 caregivers of primary school children in rural Burundi. Hierarchical regression analyses revealed that household wealth, the amount of water per person, and having a designated place for washing hands were contextual factors significantly predicting handwashing frequency, whereas the contextual factors, time spent collecting water and amount of money spent on soap, were not significant predictors. The contextual factors explained about 13% of the variance of reported handwashing frequency. The addition of the psychosocial factors to the regression model resulted in a significant 41% increase of explained variation in handwashing frequency. In this final model, the amount of water was the only contextual factor that remained a significant predictor. The most important predictors were a belief of self-efficacy, planning how, when, and where to wash hands, and always remembering to do so. The findings suggest that contextual constraints might be perceived rather than actual barriers and highlight the role of psychosocial factors in understanding hygiene behaviors. © The American Society of Tropical Medicine and Hygiene.

A Key Role for Nectin-1 in the Ventral Hippocampus in Contextual Fear Memory

PubMed Central

Grosse, Jocelyn; Krummenacher, Claude; Sandi, Carmen

2013-01-01

Nectins are cell adhesion molecules that are widely expressed in the brain. Nectin expression shows a dynamic spatiotemporal regulation, playing a role in neural migratory processes during development. Nectin-1 and nectin-3 and their heterophilic trans-interactions are important for the proper formation of synapses. In the hippocampus, nectin-1 and nectin-3 localize at puncta adherentia junctions and may play a role in synaptic plasticity, a mechanism essential for memory and learning. We evaluated the potential involvement of nectin-1 and nectin-3 in memory consolidation using an emotional learning paradigm. Rats trained for contextual fear conditioning showed transient nectin-1—but not nectin-3—protein upregulation in synapse-enriched hippocampal fractions at about 2 h posttraining. The upregulation of nectin-1 was found exclusively in the ventral hippocampus and was apparent in the synaptoneurosomal fraction. This upregulation was induced by contextual fear conditioning but not by exposure to context or shock alone. When an antibody against nectin-1, R165, was infused in the ventral-hippocampus immediately after training, contextual fear memory was impaired. However, treatment with the antibody in the dorsal hippocampus had no effect in contextual fear memory formation. Similarly, treatment with the antibody in the ventral hippocampus did not interfere with acoustic memory formation. Further control experiments indicated that the effects of ventral hippocampal infusion of the nectin-1 antibody in contextual fear memory cannot be ascribed to memory non-specific effects such as changes in anxiety-like behavior or locomotor behavior. Therefore, we conclude that nectin-1 recruitment to the perisynaptic environment in the ventral hippocampus plays an important role in the formation of contextual fear memories. Our results suggest that these mechanisms could be involved in the connection of emotional and contextual information processed in the amygdala and dorsal

Contextual mediation of perceptions in hauntings and poltergeist-like experiences.

PubMed

Lange, R; Houran, J; Harte, T M; Havens, R A

1996-06-01

The content of perceived apparitions, e.g., bereavement hallucinations, cannot be explained entirely in terms of electromagnetically induced neurochemical processes. It was shown that contextual variables influential in hallucinatory and hypnotic states also structured reported haunting experiences. As predicted, high congruency was found between the experiential content and the nature of the contextual variables. Further, the number of contextual variables involved in an experience was related to the type of experience and the state or arousal preceding the experience. Based on these findings we argue that a more complete explanation of haunting experiences should take into account both electromagnetically induced neurochemical processes and factors related to contextual mediation.

Consequences of contextual factors on clinical reasoning in resident physicians.

PubMed

McBee, Elexis; Ratcliffe, Temple; Picho, Katherine; Artino, Anthony R; Schuwirth, Lambert; Kelly, William; Masel, Jennifer; van der Vleuten, Cees; Durning, Steven J

2015-12-01

Context specificity and the impact that contextual factors have on the complex process of clinical reasoning is poorly understood. Using situated cognition as the theoretical framework, our aim was to evaluate the verbalized clinical reasoning processes of resident physicians in order to describe what impact the presence of contextual factors have on their clinical reasoning. Participants viewed three video recorded clinical encounters portraying straightforward diagnoses in internal medicine with select patient contextual factors modified. After watching each video recording, participants completed a think-aloud protocol. Transcripts from the think-aloud protocols were analyzed using a constant comparative approach. After iterative coding, utterances were analyzed for emergent themes with utterances grouped into categories, themes and subthemes. Ten residents participated in the study with saturation reached during analysis. Participants universally acknowledged the presence of contextual factors in the video recordings. Four categories emerged as a consequence of the contextual factors: (1) emotional reactions (2) behavioral inferences (3) optimizing the doctor patient relationship and (4) difficulty with closure of the clinical encounter. The presence of contextual factors may impact clinical reasoning performance in resident physicians. When confronted with the presence of contextual factors in a clinical scenario, residents experienced difficulty with closure of the encounter, exhibited as diagnostic uncertainty. This finding raises important questions about the relationship between contextual factors and clinical reasoning activities and how this relationship might influence the cost effectiveness of care. This study also provides insight into how the phenomena of context specificity may be explained using situated cognition theory.

Contextual Admissions and Affirmative Action: Developments in Higher Education Policy in England

ERIC Educational Resources Information Center

Lane, Laura; Birds, Rachel

2013-01-01

This paper explores the value of explaining contextual admissions policy directives through the conceptual lenses of meritocracy and social reproduction. It is suggested that examining these concepts can assist in highlighting some of the ideological and practical complexities associated with contextual admissions whilst providing opportunities to…

Stimulus homogeneity enhances implicit learning: evidence from contextual cueing.

PubMed

Feldmann-Wüstefeld, Tobias; Schubö, Anna

2014-04-01

Visual search for a target object is faster if the target is embedded in a repeatedly presented invariant configuration of distractors ('contextual cueing'). It has also been shown that the homogeneity of a context affects the efficiency of visual search: targets receive prioritized processing when presented in a homogeneous context compared to a heterogeneous context, presumably due to grouping processes at early stages of visual processing. The present study investigated in three Experiments whether context homogeneity also affects contextual cueing. In Experiment 1, context homogeneity varied on three levels of the task-relevant dimension (orientation) and contextual cueing was most pronounced for context configurations with high orientation homogeneity. When context homogeneity varied on three levels of the task-irrelevant dimension (color) and orientation homogeneity was fixed, no modulation of contextual cueing was observed: high orientation homogeneity led to large contextual cueing effects (Experiment 2) and low orientation homogeneity led to low contextual cueing effects (Experiment 3), irrespective of color homogeneity. Enhanced contextual cueing for homogeneous context configurations suggest that grouping processes do not only affect visual search but also implicit learning. We conclude that memory representation of context configurations are more easily acquired when context configurations can be processed as larger, grouped perceptual units. However, this form of implicit perceptual learning is only improved by stimulus homogeneity when stimulus homogeneity facilitates grouping processes on a dimension that is currently relevant in the task. Copyright © 2014 Elsevier B.V. All rights reserved.

Preserved local but disrupted contextual figure-ground influences in an individual with abnormal function of intermediate visual areas

PubMed Central

Brooks, Joseph L.; Gilaie-Dotan, Sharon; Rees, Geraint; Bentin, Shlomo; Driver, Jon

2012-01-01

Visual perception depends not only on local stimulus features but also on their relationship to the surrounding stimulus context, as evident in both local and contextual influences on figure-ground segmentation. Intermediate visual areas may play a role in such contextual influences, as we tested here by examining LG, a rare case of developmental visual agnosia. LG has no evident abnormality of brain structure and functional neuroimaging showed relatively normal V1 function, but his intermediate visual areas (V2/V3) function abnormally. We found that contextual influences on figure-ground organization were selectively disrupted in LG, while local sources of figure-ground influences were preserved. Effects of object knowledge and familiarity on figure-ground organization were also significantly diminished. Our results suggest that the mechanisms mediating contextual and familiarity influences on figure-ground organization are dissociable from those mediating local influences on figure-ground assignment. The disruption of contextual processing in intermediate visual areas may play a role in the substantial object recognition difficulties experienced by LG. PMID:22947116

The impact of cue learning, trait anxiety and genetic variation in the serotonin 1A receptor on contextual fear.

PubMed

Baas, Johanna M P; Heitland, Ivo

2015-12-01

In everyday life, aversive events are usually associated with certain predictive cues. Normally, the acquisition of these contingencies enables organisms to appropriately respond to threat. Presence of a threat cue clearly signals 'danger', whereas absence of such cues signals a period of 'safety'. Failure to identify threat cues may lead to chronic states of anxious apprehension in the context in which the threat has been imminent, which may be instrumental in the pathogenesis of anxiety disorders. In this study, existing data from 150 healthy volunteers in a cue and context virtual reality fear conditioning paradigm were reanalyzed. The aim was to further characterize the impact of cue acquisition and trait anxiety, and of a single nucleotide polymorphism in the serotonin 1A receptor gene (5-HTR1A, rs6295), on cued fear and contextual anxiety before and after fear contingencies were explicitly introduced. Fear conditioned responding was quantified with fear potentiation of the eyeblink startle reflex and subjective fear ratings. First, we replicated previous findings that the inability to identify danger cues during acquisition leads to heightened anxious apprehension in the threat context. Second, in subjects who did not identify the danger cue initially, contextual fear was associated with trait anxiety after the contingencies were explicitly instructed. Third, genetic variability within 5-HTR1A (rs6295) was associated with contextual fear independent of awareness or trait anxiety. These findings confirm that failure to acquire cue contingencies impacts contextual fear responding, in association with trait anxiety. The observed 5-HTR1A effect is in line with models of anxiety, but needs further replication. Copyright © 2014 Elsevier B.V. All rights reserved.

Global Repetition Influences Contextual Cueing

PubMed Central

Zang, Xuelian; Zinchenko, Artyom; Jia, Lina; Li, Hong

2018-01-01

Our visual system has a striking ability to improve visual search based on the learning of repeated ambient regularities, an effect named contextual cueing. Whereas most of the previous studies investigated contextual cueing effect with the same number of repeated and non-repeated search displays per block, the current study focused on whether a global repetition frequency formed by different presentation ratios between the repeated and non-repeated configurations influence contextual cueing effect. Specifically, the number of repeated and non-repeated displays presented in each block was manipulated: 12:12, 20:4, 4:20, and 4:4 in Experiments 1–4, respectively. The results revealed a significant contextual cueing effect when the global repetition frequency is high (≥1:1 ratio) in Experiments 1, 2, and 4, given that processing of repeated displays was expedited relative to non-repeated displays. Nevertheless, the contextual cueing effect reduced to a non-significant level when the repetition frequency reduced to 4:20 in Experiment 3. These results suggested that the presentation frequency of repeated relative to the non-repeated displays could influence the strength of contextual cueing. In other words, global repetition statistics could be a crucial factor to mediate contextual cueing effect. PMID:29636716

Global Repetition Influences Contextual Cueing.

PubMed

Zang, Xuelian; Zinchenko, Artyom; Jia, Lina; Assumpção, Leonardo; Li, Hong

2018-01-01

Our visual system has a striking ability to improve visual search based on the learning of repeated ambient regularities, an effect named contextual cueing. Whereas most of the previous studies investigated contextual cueing effect with the same number of repeated and non-repeated search displays per block, the current study focused on whether a global repetition frequency formed by different presentation ratios between the repeated and non-repeated configurations influence contextual cueing effect. Specifically, the number of repeated and non-repeated displays presented in each block was manipulated: 12:12, 20:4, 4:20, and 4:4 in Experiments 1-4, respectively. The results revealed a significant contextual cueing effect when the global repetition frequency is high (≥1:1 ratio) in Experiments 1, 2, and 4, given that processing of repeated displays was expedited relative to non-repeated displays. Nevertheless, the contextual cueing effect reduced to a non-significant level when the repetition frequency reduced to 4:20 in Experiment 3. These results suggested that the presentation frequency of repeated relative to the non-repeated displays could influence the strength of contextual cueing. In other words, global repetition statistics could be a crucial factor to mediate contextual cueing effect.

A model to explain human voice production

NASA Astrophysics Data System (ADS)

Vilas Bôas, C. S. N.; Gobara, S. T.

2018-05-01

This article presents a device constructed with low-cost material to demonstrate and explain voice production. It also provides a contextualized, interdisciplinary approach to introduce the study of sound waves.

1. West portal of Tunnel 25, contextual view to northeast ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. West portal of Tunnel 25, contextual view to northeast from Tunnel 24 (HAER CA-200), 135mm lens. - Central Pacific Transcontinental Railroad, Tunnel No. 25, Milepost 133.09, Applegate, Placer County, CA

Hypobaric hypoxia impairs cued and contextual fear memory in rats.

PubMed

Kumari, Punita; Kauser, Hina; Wadhwa, Meetu; Roy, Koustav; Alam, Shahnawaz; Sahu, Surajit; Kishore, Krishna; Ray, Koushik; Panjwani, Usha

2018-04-26

Fear memory is essential for survival, and its dysregulation leads to disorders. High altitude hypobaric hypoxia (HH) is known to induce cognitive decline. However, its effect on fear memory is still an enigma. We aimed to investigate the temporal effect of HH on fear conditioning and the underlying mechanism. Adult male Sprague-Dawley rats were trained for fear conditioning and exposed to simulated HH equivalent to 25,000 ft for different durations (1, 3, 7, 14 and 21 days). Subsequently, rats were tested for cued and contextual fear conditioning. Neuronal morphology, apoptosis and DNA fragmentation were studied in the medial prefrontal cortex (mPFC), hippocampus and basolateral amygdala (BLA). We observed significant deficit in cued and contextual fear acquisition (at 1, 3 and 7 days) and consolidation (cued at 1 and 3 days and contextual fear at 1, 3 and 7 days) under HH. HH exposure with retraining showed the earlier restoration of contextual fear memory. Further, we found a gradual increase in the number of pyknotic and apoptotic neurons together with the increase in DNA fragmentation in mPFC, hippocampus, and BLA up to 7 days of HH exposure. The present study concludes that HH exposure equivalent to 25000 ft induced cued and contextual fear memory deficit (acquisition and consolidation) which is found to be correlated with the neurodegenerative changes in the limbic brain regions. Copyright © 2018. Published by Elsevier B.V.

The effect of patient and contextual characteristics on racial/ethnic disparity in breast cancer mortality

PubMed Central

Sposto, Richard; Keegan, Theresa H. M.; Vigen, Cheryl; Kwan, Marilyn L.; Bernstein, Leslie; John, Esther M.; Cheng, Iona; Yang, Juan; Koo, Jocelyn; Kurian, Allison W.; Caan, Bette J.; Lu, Yani; Monroe, Kristine R.; Shariff-Marco, Salma; Gomez, Scarlett Lin; Wu, Anna H.

2016-01-01

Background Racial/ethnic disparity in breast cancer-specific mortality in the U.S. is well documented. We examined whether accounting for racial/ethnic differences in the prevalence of clinical, patient, and lifestyle and contextual factors that are associated with breast cancer-specific mortality can explain this disparity. Methods The California Breast Cancer Survivorship Consortium combined interview data from six California-based breast cancer studies with cancer registry data to create a large racially diverse cohort of women with primary invasive breast cancer. We examined the contribution of variables in a previously reported Cox regression baseline model plus additional contextual, physical activity, body size, and comorbidity variables to the racial/ethnic disparity in breast cancer-specific mortality. Results The cohort comprised 12,098 women. Fifty-four percent were non-Latina Whites, 17% African Americans, 17% Latinas, and 12% Asian Americans. In a model adjusting only for age and study, breast cancer-specific hazard ratios relative to Whites were 1.69 (95% CI 1.46 -1.96), 1.00 (0.84 - 1.19), and 0.52 (0.33 - 0.85) for African Americans, Latinas, and Asian Americans respectively. Adjusting for baseline-model variables decreased disparity primarily by reducing the hazard ratio for African Americans to 1.13 (0.96 - 1.33). The most influential variables were related to disease characteristics, neighborhood socioeconomic status, and smoking status at diagnosis. Other variables had negligible impact on disparity. Conclusions While contextual, physical activity, body size, and comorbidity variables may influence breast cancer-specific mortality, they do not explain racial/ethnic mortality disparity. Impact Other factors besides those investigated here may explain the existing racial/ethnic disparity in mortality. PMID:27197297

Contextual Risk Profiles and Trajectories of Adolescent Dating Violence Perpetration.

PubMed

Reyes, H Luz McNaughton; Foshee, Vangie A; Markiewitz, Nathan; Chen, May S; Ennett, Susan T

2018-04-09

Social ecological and developmental system perspectives suggest that interactions among factors within and across multiple contexts (e.g., neighborhood, peer, family) must be considered in explaining dating violence perpetration. Yet, to date, most extant research on dating violence has focused on individual, rather than contextual predictors, and used variable-centered approaches that fail to capture the configurations of factors that may jointly explain involvement in dating violence. The current study used a person-centered approach, latent profile analysis, to identify key configurations (or profiles) of contextual risk and protective factors for dating violence perpetration across the neighborhood, school, friend and family contexts. We then examine the longitudinal associations between these contextual risk profiles, assessed during middle school, and trajectories of psychological and physical dating violence perpetration across grades 8 through 12. Five contextual risk profiles were identified: school, neighborhood, and family risk; school and family risk; school and friend risk; school and neighborhood risk; and low risk. The highest levels of psychological and physical perpetration across grades 8 through 12 were among adolescents in the profile characterized by high levels of school, neighborhood, and family risk. Results suggest that early interventions to reduce violence exposure and increase social regulation across multiple social contexts may be effective in reducing dating violence perpetration across adolescence.

Short-term inhibition of 11β-hydroxysteroid dehydrogenase type 1 reversibly improves spatial memory but persistently impairs contextual fear memory in aged mice.

PubMed

Wheelan, Nicola; Webster, Scott P; Kenyon, Christopher J; Caughey, Sarah; Walker, Brian R; Holmes, Megan C; Seckl, Jonathan R; Yau, Joyce L W

2015-04-01

High glucocorticoid levels induced by stress enhance the memory of fearful events and may contribute to the development of anxiety and posttraumatic stress disorder. In contrast, elevated glucocorticoids associated with ageing impair spatial memory. We have previously shown that pharmacological inhibition of the intracellular glucocorticoid-amplifying enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) improves spatial memory in aged mice. However, it is not known whether inhibition of 11β-HSD1 will have any beneficial effects on contextual fear memories in aged mice. Here, we examined the effects of UE2316, a selective 11β-HSD1 inhibitor which accesses the brain, on both spatial and contextual fear memories in aged mice using a vehicle-controlled crossover study design. Short-term UE2316 treatment improved spatial memory in aged mice, an effect which was reversed when UE2316 was substituted with vehicle. In contrast, contextual fear memory induced by foot-shock conditioning was significantly reduced by UE2316 in a non-reversible manner. When the order of treatment was reversed following extinction of the original fear memory, and a second foot-shock conditioning was given in a novel context, UE2316 treated aged mice (previously on vehicle) now showed increased fear memory compared to vehicle-treated aged mice (previously on UE2316). Renewal of the original extinguished fear memory triggered by exposure to a new environmental context may explain these effects. Thus 11β-HSD1 inhibition reverses spatial memory impairments with ageing while reducing the strength and persistence of new contextual fear memories. Potentially this could help prevent anxiety-related disorders in vulnerable elderly individuals. Copyright © 2014 Elsevier Ltd. All rights reserved.

Contextual modulation and stimulus selectivity in extrastriate cortex.

PubMed

Krause, Matthew R; Pack, Christopher C

2014-11-01

Contextual modulation is observed throughout the visual system, using techniques ranging from single-neuron recordings to behavioral experiments. Its role in generating feature selectivity within the retina and primary visual cortex has been extensively described in the literature. Here, we describe how similar computations can also elaborate feature selectivity in the extrastriate areas of both the dorsal and ventral streams of the primate visual system. We discuss recent work that makes use of normalization models to test specific roles for contextual modulation in visual cortex function. We suggest that contextual modulation renders neuronal populations more selective for naturalistic stimuli. Specifically, we discuss contextual modulation's role in processing optic flow in areas MT and MST and for representing naturally occurring curvature and contours in areas V4 and IT. We also describe how the circuitry that supports contextual modulation is robust to variations in overall input levels. Finally, we describe how this theory relates to other hypothesized roles for contextual modulation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ethnic disparities in adolescent body mass index in the United States: The role of parental socioeconomic status and economic contextual factors

PubMed Central

Powell, Lisa M.; Wada, Roy; Krauss, Ramona C.; Wang, Youfa

2013-01-01

This paper examined the importance of household and economic contextual factors as determinants of ethnic disparities in adolescent body mass index (BMI). Individual-level data from the National Longitudinal Survey of Youth 1997 for the years 1997 through 2000 were combined with economic contextual data on food prices, outlet density and median household income. The Oaxaca–Blinder decomposition method was used to examine the factors that could help explain ethnic disparities in BMI. Ethnic differences in household demographic, parental socioeconomic status (SES), and economic contextual factors explained the majority of the male black–white (63%), male Hispanic–white (78%) and female Hispanic–white (62%) BMI gaps but less than one-half of the female black–white BMI gap (44%). We found that adding the economic contextual factors increased the explained portion of the ethnic BMI gap for both female and male adolescents: the economic contextual factors explained 28% and 38% of the black–white and Hispanic–white BMI gaps for males and 13% and 8% of the black–white and Hispanic–white BMI gaps for females, respectively. Parental SES was more important in explaining the Hispanic–white BMI gap than the black–white BMI gap for both genders, whereas neighborhood economic contextual factors were more important in explaining the male BMI gap than the female BMI gap for both black–white and Hispanic–white ethnic disparities. A significantly large portion of the ethnic BMI gap, however, remained unexplained between black and white female adolescents. PMID:22607746

1. West portal of Tunnel 34, contextual view to northeast ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. West portal of Tunnel 34, contextual view to northeast from inside east end of Tunnel 33 (Cape Horn Tunnel), 135mm lens with electronic flash fill. - Central Pacific Transcontinental Railroad, Tunnel No. 34, Milepost 145.4, Colfax, Placer County, CA

Effects of S(+)-efonidipine on the rabbit sinus node action potential and calcium channel subunits Ca(V)1.2, Ca(V)1.3 and Ca(V)3.1.

PubMed

Tanaka, Hikaru; Namekata, Iyuki; Ogawa, Toru; Tsuneoka, Yayoi; Komikado, Chisa; Takahara, Akira; Iida-Tanaka, Naoko; Izumi-Nakaseko, Hiroko; Tsuru, Hiromichi; Adachi-Akahane, Satomi

2010-12-15

The effect of S(+)-efonidipine on sinus node action potential and calcium channel α-subunits was examined. The slope of the phase 4 depolarization of isolated rabbit sinus node tissue was significantly reduced by S(+)-efonidipine (1 μM), slightly reduced by nifedipine (1 μM), but was not affected by R(-)-efonidipine. S(+)-efonidipine (1 μM), inhibited the expressed Ca(V)1.2, Ca(V)1.3 and Ca(V)3.1 channel currents by 75.7%, 75.3% and 94.0%, nifedipine 84.0%, 43.2% and 14.9%, and R(-)-efonidipine 30.0%, 19.6% and 92.8%, respectively. Thus, the prolongation of the phase 4 depolarization of the rabbit sinus node by S(+)-efonidipine may be explained by blockade of the Ca(V)1.3 channel current. Copyright © 2010 Elsevier B.V. All rights reserved.

Dopamine D1-like receptor signalling in the hippocampus and amygdala modulates the acquisition of contextual fear conditioning.

PubMed

Heath, Florence C; Jurkus, Regimantas; Bast, Tobias; Pezze, Marie A; Lee, Jonathan L C; Voigt, J Peter; Stevenson, Carl W

2015-07-01

Dopamine D1-like receptor signalling is involved in contextual fear conditioning, but the brain regions involved and its role in other contextual fear memory processes remain unclear. The objective of this study was to investigate (1) the effects of SCH 23390, a dopamine D1/D5 receptor antagonist, on contextual fear memory encoding, retrieval and reconsolidation, and (2) if the effects of SCH 23390 on conditioning involve the dorsal hippocampus (DH) and/or basolateral amygdala (BLA). Rats were used to examine the effects of systemically administering SCH 23390 on the acquisition, consolidation, retrieval and reconsolidation of contextual fear memory, and on locomotor activity and shock sensitivity. We also determined the effects of MK-801, an NMDA receptor antagonist, on contextual fear memory reconsolidation. The effects of infusing SCH 23390 locally into DH or BLA on contextual fear conditioning and locomotor activity were also examined. Systemic administration of SCH 23390 impaired contextual fear conditioning but had no effects on fear memory consolidation, retrieval or reconsolidation. MK-801 was found to impair reconsolidation, suggesting that the behavioural parameters used allowed for the pharmacological disruption of memory reconsolidation. The effects of SCH 23390 on conditioning were unlikely the result of any lasting drug effects on locomotor activity at memory test or any acute drug effects on shock sensitivity during conditioning. SCH 23390 infused into either DH or BLA impaired contextual fear conditioning and decreased locomotor activity. These findings suggest that dopamine D1-like receptor signalling in DH and BLA contributes to the acquisition of contextual fear memory.

Contextual Fraction as a Measure of Contextuality.

PubMed

Abramsky, Samson; Barbosa, Rui Soares; Mansfield, Shane

2017-08-04

We consider the contextual fraction as a quantitative measure of contextuality of empirical models, i.e., tables of probabilities of measurement outcomes in an experimental scenario. It provides a general way to compare the degree of contextuality across measurement scenarios; it bears a precise relationship to violations of Bell inequalities; its value, and a witnessing inequality, can be computed using linear programing; it is monotonic with respect to the "free" operations of a resource theory for contextuality; and it measures quantifiable advantages in informatic tasks, such as games and a form of measurement-based quantum computing.

Contextual Fraction as a Measure of Contextuality

NASA Astrophysics Data System (ADS)

Abramsky, Samson; Barbosa, Rui Soares; Mansfield, Shane

2017-08-01

We consider the contextual fraction as a quantitative measure of contextuality of empirical models, i.e., tables of probabilities of measurement outcomes in an experimental scenario. It provides a general way to compare the degree of contextuality across measurement scenarios; it bears a precise relationship to violations of Bell inequalities; its value, and a witnessing inequality, can be computed using linear programing; it is monotonic with respect to the "free" operations of a resource theory for contextuality; and it measures quantifiable advantages in informatic tasks, such as games and a form of measurement-based quantum computing.

Short-term inhibition of 11β-hydroxysteroid dehydrogenase type 1 reversibly improves spatial memory but persistently impairs contextual fear memory in aged mice

PubMed Central

Wheelan, Nicola; Webster, Scott P.; Kenyon, Christopher J.; Caughey, Sarah; Walker, Brian R.; Holmes, Megan C.; Seckl, Jonathan R.; Yau, Joyce L.W.

2015-01-01

High glucocorticoid levels induced by stress enhance the memory of fearful events and may contribute to the development of anxiety and posttraumatic stress disorder. In contrast, elevated glucocorticoids associated with ageing impair spatial memory. We have previously shown that pharmacological inhibition of the intracellular glucocorticoid-amplifying enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) improves spatial memory in aged mice. However, it is not known whether inhibition of 11β-HSD1 will have any beneficial effects on contextual fear memories in aged mice. Here, we examined the effects of UE2316, a selective 11β-HSD1 inhibitor which accesses the brain, on both spatial and contextual fear memories in aged mice using a vehicle-controlled crossover study design. Short-term UE2316 treatment improved spatial memory in aged mice, an effect which was reversed when UE2316 was substituted with vehicle. In contrast, contextual fear memory induced by foot-shock conditioning was significantly reduced by UE2316 in a non-reversible manner. When the order of treatment was reversed following extinction of the original fear memory, and a second foot-shock conditioning was given in a novel context, UE2316 treated aged mice (previously on vehicle) now showed increased fear memory compared to vehicle-treated aged mice (previously on UE2316). Renewal of the original extinguished fear memory triggered by exposure to a new environmental context may explain these effects. Thus 11β-HSD1 inhibition reverses spatial memory impairments with ageing while reducing the strength and persistence of new contextual fear memories. Potentially this could help prevent anxiety-related disorders in vulnerable elderly individuals. PMID:25497454

A unifying Bayesian account of contextual effects in value-based choice

PubMed Central

Friston, Karl J.; Dolan, Raymond J.

2017-01-01

Empirical evidence suggests the incentive value of an option is affected by other options available during choice and by options presented in the past. These contextual effects are hard to reconcile with classical theories and have inspired accounts where contextual influences play a crucial role. However, each account only addresses one or the other of the empirical findings and a unifying perspective has been elusive. Here, we offer a unifying theory of context effects on incentive value attribution and choice based on normative Bayesian principles. This formulation assumes that incentive value corresponds to a precision-weighted prediction error, where predictions are based upon expectations about reward. We show that this scheme explains a wide range of contextual effects, such as those elicited by other options available during choice (or within-choice context effects). These include both conditions in which choice requires an integration of multiple attributes and conditions where a multi-attribute integration is not necessary. Moreover, the same scheme explains context effects elicited by options presented in the past or between-choice context effects. Our formulation encompasses a wide range of contextual influences (comprising both within- and between-choice effects) by calling on Bayesian principles, without invoking ad-hoc assumptions. This helps clarify the contextual nature of incentive value and choice behaviour and may offer insights into psychopathologies characterized by dysfunctional decision-making, such as addiction and pathological gambling. PMID:28981514

1. CONTEXTUAL VIEW OF THE NINE MILE HYDROELECTRIC DEVELOPMENT (HED), ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. CONTEXTUAL VIEW OF THE NINE MILE HYDROELECTRIC DEVELOPMENT (HED), SHOWING DAM AND POWERHOUSE IN FOREGROUND, VILLAGE COMPLEX IN RIGHT BACKGROUND, LOOKING WEST FROM ABOVE STATE HIGHWAY 291 - Nine Mile Hydroelectric Development, State Highway 291 along Spokane River, Nine Mile Falls, Spokane County, WA

1. CONTEXTUAL VIEW OF THE UPPER FALLS GATE HOUSE, FOREBAY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. CONTEXTUAL VIEW OF THE UPPER FALLS GATE HOUSE, FOREBAY IN FOREGROUND, LOOKING NORTH. - Washington Water Power Spokane River Upper Falls Hydroelectric Development, Gate House, Spokane River, approximately 0.5 mile northeast of intersection of Spokane Falls Boulevard & Post Street, Spokane, Spokane County, WA

An update on contextual fear memory mechanisms: Transition between Amygdala and Hippocampus.

PubMed

Chaaya, Nicholas; Battle, Andrew R; Johnson, Luke R

2018-05-09

Context is an ever-present combination of discrete environmental elements capable of influencing many psychological processes. When context is associated with an aversive stimulus, a permanent contextual fear memory is formed. Context is hypothesized to greatly influence the treatability of various fear-based pathologies, in particular, post-traumatic stress disorder (PTSD). In order to understand how contextual fear memories are encoded and impact underlying fear pathology, delineation of the underlying neural circuitry of contextual fear memory consolidation and maintenance is essential. Past understandings of contextual fear suggest that the hippocampus only creates a unitary, or single, representation of context. This representation is sent to the amygdala, which creates the associative contextual fear memory. In contrast, here we review new evidence from the literature showing contextual fear memories to be consolidated and maintained by both amygdala and hippocampus. Based on this evidence, we revise the current model of contextual fear memory consolidation, highlighting a larger role for hippocampus. This new model may better explain the role of the hippocampus in PTSD. Copyright © 2018 Elsevier Ltd. All rights reserved.

Assessment of the magnitude of geographical variations in the duration of non-work-related sickness absence by individual and contextual factors.

PubMed

Torá-Rocamora, Isabel; Martínez, José Miguel; Gimeno, David; Alberti, Constança; Jardí, Josefina; Manzanera, Rafael; Benavides, Fernando G; Delclos, George

2015-01-01

To examine variation in the duration of non-work-related sickness absence (NWRSA) across geographical areas and the degree to which this variation can be explained by individual and/or contextual factors. All first NWRSA episodes ending in 2007 and 2010 were analyzed. Individual (diagnosis, age, sex) and contextual factors (healthcare resources, socioeconomic factors) were analyzed to assess how much of the geographical variation was explained by these factors. Median NWRSA durations in quartiles were mapped by counties in Catalonia. Multilevel Cox proportional hazard regression models with episodes nested within counties were fitted to quantify the magnitude of this variation. The proportional change in variance (PCV), median hazard ratios (MHR) and interquartile hazard ratios (IHR) were calculated. We found a geographical pattern in the duration of NWRSA, with longer duration in northwestern Catalonia. There was a small, but statistically significant, geographical variation in the duration of NWRSA, which mostly decreased after adjustment for individual factors in both women (PCV=34.98%, MHR=1.09, IHR=1.13 in 2007; PCV=34.68%, MHR=1.11, IHR=1.28 in 2010) and men (PCV=39.88%, MHR=1.10, IHR=1.27 in 2007; PCV=45.93%, MHR=1.10, IHR=1.25 in 2010); only in the case of women in 2010 was there a reduction in county-level variance due to contextual covariates (PCV=16.18%, MHR=1.12, IHR=1.32). County-level variation in the duration of NWRSA was small and was explained more by individual than by contextual variables. Knowledge of geographic differences in NWRSA duration is needed to plan specific programs and interventions to minimize these differences. Copyright © 2014 SESPAS. Published by Elsevier Espana. All rights reserved.

1. West portal of Tunnel 27 in distance, contextual view ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. West portal of Tunnel 27 in distance, contextual view to northeast looking past Tunnel 26 (HAER CA-202) from atop east portal of Tunnel 25 (HAER CA-201), 380mm lens. - Central Pacific Transcontinental Railroad, Tunnel No. 27, Milepost 133.9, Applegate, Placer County, CA

Correlates of Depressed Mothers' Sensitivity toward Their Infants: The Role of Maternal, Child, and Contextual Characteristics

ERIC Educational Resources Information Center

van Doesum, Karin T. M.; Hosman, Clemens M. H.; Riksen-Walraven, J. Marianne; Hoefnagels, Cees

2007-01-01

Objective: To examine various maternal, child, and contextual characteristics, as well as the number of risk factors present, to distinguish which factors explain variance in the sensitivity of depressed mothers toward their infants. Method: Participants were depressed mothers (n = 84) with their infants ages 1 month up to 1 year. Mothers were…

1. CONTEXTUAL VIEW OF BRIDGE IN SETTING, LOOKING SOUTHWEST, FROM ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. CONTEXTUAL VIEW OF BRIDGE IN SETTING, LOOKING SOUTHWEST, FROM DOWNSTREAM. Crew, vehicles, boats, and equipment are from the California Department of Transportation's Transportation Laboratory conducting test borings for the replacement bridge. - Smith River Bridge, CA State Highway 199 Spanning Smith River, Crescent City, Del Norte County, CA

Contextual predictability shapes signal autonomy.

PubMed

Winters, James; Kirby, Simon; Smith, Kenny

2018-07-01

Aligning on a shared system of communication requires senders and receivers reach a balance between simplicity, where there is a pressure for compressed representations, and informativeness, where there is a pressure to be communicatively functional. We investigate the extent to which these two pressures are governed by contextual predictability: the amount of contextual information that a sender can estimate, and therefore exploit, in conveying their intended meaning. In particular, we test the claim that contextual predictability is causally related to signal autonomy: the degree to which a signal can be interpreted in isolation, without recourse to contextual information. Using an asymmetric communication game, where senders and receivers are assigned fixed roles, we manipulate two aspects of the referential context: (i) whether or not a sender shares access to the immediate contextual information used by the receiver in interpreting their utterance; (ii) the extent to which the relevant solution in the immediate referential context is generalisable to the aggregate set of contexts. Our results demonstrate that contextual predictability shapes the degree of signal autonomy: when the context is highly predictable (i.e., the sender has access to the context in which their utterances will be interpreted, and the semantic dimension which discriminates between meanings in context is consistent across communicative episodes), languages develop which rely heavily on the context to reduce uncertainty about the intended meaning. When the context is less predictable, senders favour systems composed of autonomous signals, where all potentially relevant semantic dimensions are explicitly encoded. Taken together, these results suggest that our pragmatic faculty, and how it integrates information from the context in reducing uncertainty, plays a central role in shaping language structure. Copyright © 2018 Elsevier B.V. All rights reserved.

1. CONTEXTUAL VIEW OF WASTE CALCINING FACILITY. CAMERA FACING NORTHEAST. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. CONTEXTUAL VIEW OF WASTE CALCINING FACILITY. CAMERA FACING NORTHEAST. ON RIGHT OF VIEW IS PART OF EARTH/GRAVEL SHIELDING FOR BIN SET. AERIAL STRUCTURE MOUNTED ON POLES IS PNEUMATIC TRANSFER SYSTEM FOR DELIVERY OF SAMPLES BEING SENT FROM NEW WASTE CALCINING FACILITY TO THE CPP REMOTE ANALYTICAL LABORATORY. INEEL PROOF NUMBER HD-17-1. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

Memory retrieval after contextual fear conditioning induces c-Fos and JunB expression in CA1 hippocampus.

PubMed

Strekalova, T; Zörner, B; Zacher, C; Sadovska, G; Herdegen, T; Gass, P

2003-02-01

Using specific polyclonal antisera against c-Fos, JunB, c-Jun and JunD, we tried to identify the candidate transcription factors of the immediate early gene family which may contribute to the molecular processes during contextual memory reconsolidation. For that purpose we analyzed the expression of these proteins in the hippocampus after contextual memory retrieval in a mouse model of fear conditioning. A single exposure to a foot shock of 0.8 mA was sufficient to induce robust contextual fear conditioning in C57BI/6N mice. In these mice context dependent memory retrieval evoked a marked induction of c-Fos and JunB, but not of c-Jun and JunD, in pyramidal CA1 neurons of the dorsal hippocampus. In contrast, mice exposed and re-exposed only to the context, without foot shock, did not show behavioral signs of contextual fear conditioning and exhibited significantly less expression of c-Fos and JunB in CA1 neurons. Mice which received a foot shock but were not re-exposed to the context revealed no immediate early gene induction. These results demonstrate that contextual memory retrieval is associated with de novo synthesis of specific members of the Fos/Jun transcription factor family. Therefore we suggest that these genes may contribute to plasticity and reconsolidation accompanying the retrieval process. The specific activation of CA1 neurons during the retrieval of contextual fear associations supports the postulated concept of a mnemonic role of this hippocampal subsector during the retrieval of contextual informations.

1. West portal of Tunnel 23, contextual view to the ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. West portal of Tunnel 23, contextual view to the west-northwest, 380mm lens. Tunnel 22 pierces the toe of Lookout Point. Note that the tracks have been realigned toward the Willamette River to bypass Tunnel 23. - Southern Pacific Railroad Natron Cutoff, Tunnel 23, Milepost 584.5, Westfir, Lane County, OR

1. CONTEXTUAL VIEW OF DRY DOCK NO. 4, LOOKING NORTHEAST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. CONTEXTUAL VIEW OF DRY DOCK NO. 4, LOOKING NORTHEAST FROM ROOF OF BUILDING NO. 620. NOTE OVERHEAD CRANE (STRUCTURE NO. 1043) AND STRUCTURAL ASSEMBLY SHOP (BUILDING NO. 541) IN LEFT BACKGROUND. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Dry Dock No. 4, Broad Street south of Government Avenue, Philadelphia, Philadelphia County, PA

Impairment of contextual conditioned fear extinction after microinjection of alpha-1-adrenergic blocker prazosin into the medial prefrontal cortex.

PubMed

Do-Monte, Fabrício H M; Allensworth, Melody; Carobrez, Antônio P

2010-07-29

Long-lasting memories of aversive or stressful events have been associated with the noradrenergic system activation. Alpha-1-adrenergic antagonist prazosin has successfully been used in the last years to treat anxiety disorders related to aversive memories recurrence in humans. Contextual conditioned fear extinction paradigm in rats has been used to better understand the mechanisms involved in the attenuation of defensive behaviour after a traumatic situation. Here we investigated the effects of systemic administration of prazosin in the fear extinction processes. Rats were previously paired in a contextual fear conditioning box (1 footshock, 1 mA, 2s duration), further returning to the same box during three consecutive days receiving an intraperitoneal injection of vehicle or prazosin 30 min before (acquisition of extinction; 0.1 or 0.5mg/kg) or immediately after (consolidation of extinction, 0.5 or 1.5mg/kg) each extinction session (10 min). On the last day, all animals were re-exposed undrugged to the apparatus. Since the medial prefrontal cortex (mPFC) has been described as a key structure in the modulation of conditioned fear extinction, the effects of intra-mPFC microinjection (0.2 microl per side) of vehicle (PBS) or prazosin (0.75 or 2.5 nmol) in the acquisition of fear extinction (10 min before extinction session 1) were further evaluated. Subjects were drug-free re-exposed to the same box in the next day (extinction session 2). The percentage of freezing time was used as the memory retention parameter. The results showed that either systemic or intra-mPFC-alpha-1-adrenergic blockade increased the freezing time in the last extinction sessions, suggesting impairment of the extinction of contextual conditioned fear in rats. Copyright 2010 Elsevier B.V. All rights reserved.

Individual and contextual factors associated with verbal bullying among Brazilian adolescents.

PubMed

Azeredo, Catarina Machado; Levy, Renata Bertazzi; Araya, Ricardo; Menezes, Paulo Rossi

2015-05-01

Few studies have been carried out in low- middle-income countries assessing contextual characteristics associated with bullying. This study aimed to assess the relative importance of contextual (school and city) and individual-level factors to explain the variance in verbal bullying among a nationally representative sample of Brazilian adolescents. 59,348 students from 1,453 schools and 26 state capitals and the Federal District participated in the National Survey of School Health among 9th Grade Students (PeNSE, 2009). We performed multilevel logistic regression in a three level model (individual, school and city). The 30-day prevalence of verbal bullying among these students was 14.2%. We found that 1.8% and 0.3% of the total variance in bullying occurred at school-level and city-level, respectively, and 97.9% at individual-level. At city-level, all factors included failed to demonstrate a significant association with bullying (p < 0.05) whereas at school-level, private schools presented more bullying than public schools (OR = 1.17, CI 1.04-1.31). At individual-level, male gender, younger age, not living with both parents, exposed to domestic violence, under or overweight were all associated with bullying. All socioeconomic indicators assessed contributed little to explain the variance in bullying at individual, school or city-level. Population subgroups at risk identified according to their individual profile could be targeted in future interventions in Brazil.

Neural representations of contextual guidance in visual search of real-world scenes.

PubMed

Preston, Tim J; Guo, Fei; Das, Koel; Giesbrecht, Barry; Eckstein, Miguel P

2013-05-01

Exploiting scene context and object-object co-occurrence is critical in guiding eye movements and facilitating visual search, yet the mediating neural mechanisms are unknown. We used functional magnetic resonance imaging while observers searched for target objects in scenes and used multivariate pattern analyses (MVPA) to show that the lateral occipital complex (LOC) can predict the coarse spatial location of observers' expectations about the likely location of 213 different targets absent from the scenes. In addition, we found weaker but significant representations of context location in an area related to the orienting of attention (intraparietal sulcus, IPS) as well as a region related to scene processing (retrosplenial cortex, RSC). Importantly, the degree of agreement among 100 independent raters about the likely location to contain a target object in a scene correlated with LOC's ability to predict the contextual location while weaker but significant effects were found in IPS, RSC, the human motion area, and early visual areas (V1, V3v). When contextual information was made irrelevant to observers' behavioral task, the MVPA analysis of LOC and the other areas' activity ceased to predict the location of context. Thus, our findings suggest that the likely locations of targets in scenes are represented in various visual areas with LOC playing a key role in contextual guidance during visual search of objects in real scenes.

[Prediction of mathematics achievement: effect of personal, socioeducational and contextual variables].

PubMed

Rosário, Pedro; Lourenço, Abílio; Paiva, Olímpia; Rodrigues, Adriana; Valle, Antonio; Tuero-Herrero, Ellián

2012-05-01

Based upon the self-regulated learning theoretical framework this study examined to what extent students' Math school achievement (fifth to ninth graders from compulsory education) can be explained by different cognitive-motivational, social, educational, and contextual variables. A sample of 571 students (10 to 15 year old) enrolled in the study. Findings suggest that Math achievement can be predicted by self-efficacy in Math, school success and self-regulated learning and that these same variables can be explained by other motivational (ej., achievement goals) and contextual variables (school disruption) stressing this way the main importance of self-regulated learning processes and the role context can play in the promotion of school success. The educational implications of the results to the school levels taken are also discussed in the present paper.

1. CONTEXTUAL VIEW OF THE POST FALLS POWERHOUSE LOOKING DOWNSTREAM. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. CONTEXTUAL VIEW OF THE POST FALLS POWERHOUSE LOOKING DOWNSTREAM. POWER PLANT AND INTAKE GATES ARE IN THE LEFT FOREGROUND, AND THE ATTACHED 'OLD SWITCHING BUILDING' (NOW ABANDONED) IS IN THE RIGHT BACKGROUND, LOOKING NORTHWEST. - Washington Water Power Company Post Falls Power Plant, Middle Channel Powerhouse & Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

BJUT at TREC 2015 Contextual Suggestion Track

DTIC Science & Technology

2015-11-20

BJUT at TREC 2015 Contextual Suggestion Track Weitong Chen1,2,3, Hanchen Li1,2,3, Zhen Yang1,2,3,⇤ 1. College of Computer Science, Beijing University...CTISCP, Beijing 100124, China ⇤yangzhen@bjut.edu.cn Abstract In this paper we described our efforts for TREC contextual suggestion task. Our goal of this...experiments to evaluate the proposed framework on TREC 2015 Contextual Suggestion data set, and, as would be expected, the results demonstrate its generality

Contextual factors related to implementation of classroom physical activity breaks.

PubMed

Carlson, Jordan A; Engelberg, Jessa K; Cain, Kelli L; Conway, Terry L; Geremia, Carrie; Bonilla, Edith; Kerner, Jon; Sallis, James F

2017-09-01

Brief structured physical activity in the classroom is effective for increasing student physical activity. The present study investigated the association between implementation-related contextual factors and intervention implementation after adoption of a structured classroom physical activity intervention. Six elementary-school districts adopted structured classroom physical activity programs in 2013-2014. Implementation contextual factors and intervention implementation (structured physical activity provided in past week or month, yes/no) were assessed using surveys of 337 classroom teachers from 24 schools. Mixed-effects models accounted for the nested design. Availability of resources (yes/no, ORs = 1.91-2.93) and implementation climate z-scores (ORs = 1.36-1.47) were consistently associated with implementation. Teacher-perceived classroom behavior benefits (OR = 1.29) but not student enjoyment or health benefits, and time (OR = 2.32) and academic (OR = 1.63) barriers but not student cooperation barriers were associated with implementation (all z-scores). Four implementation contextual factor composites had an additive association with implementation (OR = 1.64 for each additional favorable composite). Training and technical assistance alone may not support a large proportion of teachers to implement structured classroom physical activity. In addition to lack of time and interference with academic lessons, school climate related to whether administrators and other teachers were supportive of the intervention were key factors explaining whether teachers implemented the intervention. Evidence-based implementation strategies are needed for effectively communicating the benefits of classroom physical activity on student behavior and improving teacher and administrator climate/attitudes around classroom physical activity.

The importance of context: evidence that contextual representations increase intrusive memories.

PubMed

Pearson, David G; Ross, Fiona D C; Webster, Victoria L

2012-03-01

Intrusive memories appear to enter consciousness via involuntary rather than deliberate recollection. Some clinical accounts of PTSD seek to explain this phenomenon by making a clear distinction between the encoding of sensory-based and contextual representations. Contextual representations have been claimed to actively reduce intrusions by anchoring encoded perceptual data for an event in memory. The current analogue trauma study examined this hypothesis by manipulating contextual information independently from encoded sensory-perceptual information. Participants' viewed images selected from the International Affective Picture System that depicted scenes of violence and bodily injury. Images were viewed either under neutral conditions or paired with contextual information. Two experiments revealed a significant increase in memory intrusions for images paired with contextual information in comparison to the same images viewed under neutral conditions. In contrast to the observed increase in intrusion frequency there was no effect of contextual representations on voluntary memory for the images. The vividness and emotionality of memory intrusions were also unaffected. The analogue trauma paradigm may fail to replicate the effect of extreme stress on encoding postulated to occur during PTSD. These findings question the assertion that intrusive memories develop from a lack of integration between sensory-based and contextual representations in memory. Instead it is argued contextual representations play a causal role in increasing the frequency of intrusions by increasing the sensitivity of memory to involuntary retrieval by associated internal and external cues. Copyright © 2011 Elsevier Ltd. All rights reserved.

Encoding, consolidation, and retrieval of contextual memory: differential involvement of dorsal CA3 and CA1 hippocampal subregions.

PubMed

Daumas, Stéphanie; Halley, Hélène; Francés, Bernard; Lassalle, Jean-Michel

2005-01-01

Studies on human and animals shed light on the unique hippocampus contributions to relational memory. However, the particular role of each hippocampal subregion in memory processing is still not clear. Hippocampal computational models and theories have emphasized a unique function in memory for each hippocampal subregion, with the CA3 area acting as an autoassociative memory network and the CA1 area as a critical output structure. In order to understand the respective roles of the CA3- and CA1-hippocampal areas in the formation of contextual memory, we studied the effects of the reversible inactivation by lidocaine of the CA3 or CA1 areas of the dorsal hippocampus on acquisition, consolidation, and retrieval of a contextual fear conditioning. Whereas infusions of lidocaine never impaired elementary tone conditioning, their effects on contextual conditioning provided interesting clues about the role of these two hippocampal regions. They demonstrated first that the CA3 area is necessary for the rapid elaboration of a unified representation of the context. Secondly, they suggested that the CA1 area is rather involved in the consolidation process of contextual memory. Third, they showed that CA1 or CA3 inactivation during retention test has no effect on contextual fear retrieval when a recognition memory procedure is used. In conclusion, our findings point as evidence that CA1 and CA3 subregions of the dorsal hippocampus play important and different roles in the acquisition and consolidation of contextual fear memory, whereas they are not required for context recognition.

Contextual view showing H1 on left and H270 in background; ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Contextual view showing H1 on left and H270 in background; camera facing north. - Mare Island Naval Shipyard, Hospital Headquarters, Johnson Lane, west side at intersection of Johnson Lane & Cossey Street, Vallejo, Solano County, CA

1. West portal of Tunnel 26, contextual view to northeast ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. West portal of Tunnel 26, contextual view to northeast from atop Tunnel 25 (HAER CA-201), with Tunnel 27 (HAER CA-203) visible in distance, 210mm lens. View is along new line, with original Central Pacific Transcontinental line crossing over the top above Tunnel 26. - Central Pacific Transcontinental Railroad, Tunnel No. 26, Milepost 133.29, Applegate, Placer County, CA

Sexual behavior modulates contextual fear memory through dopamine D1/D5 receptors.

PubMed

Bai, Hua-Yi; Cao, Jun; Liu, Na; Xu, Lin; Luo, Jian-Hong

2009-03-01

Traumatic events always lead to aversive emotional memory, i.e., fear memory. In contrast, positive events in daily life such as sex experiences seem to reduce aversive memory after aversive events. Thus, we hypothesized that post-traumatic pleasurable experiences, especially instinctive behaviors such as sex, might modulate traumatic memory through a memory competition mechanism. Here, we first report that male rats persistently expressed much lower fear responses when exposed to females, but not when exposed to males, for 24 h immediately after contextual fear conditioning. Remarkably, this effect of sexual behavior was blocked by either systemic or intrahippocampal injection of the dopamine D1/D5 receptor antagonist R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (SCH23390) and was mimicked by systemic but not intrahippocampal injection of the D1/D5 receptor agonist R(+)-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-7,8-diol hydrochloride (SKF39393). Furthermore, as a candidate mechanism underlying contextual fear memory, the impaired induction of hippocampal long-term potentiation (LTP) elicited by conditioned fear was rescued in male rats immediately exposed to female but not male rats for 24 h. Systemic injection of the dopamine D1/D5 receptor antagonist SCH23390 or agonist SKF38393 prevented or mimicked the effect of sexual behavior on the impaired induction of hippocampal LTP. Thus, our finding suggests that dopaminergic functions may, at least partially, govern competition between contextual fear and enjoyable memories through the modulation of hippocampal LTP.

Leaked GeV CRs from a Broken Shell: Explaining 9 Years of Fermi-LAT Data of SNR W28

NASA Astrophysics Data System (ADS)

Cui, Yudong; Yeung, Paul K. H.; Tam, P. H. Thomas; Pühlhofer, Gerd

2018-06-01

Supernova remnant (SNR)W28 is well known for its classic hadronic scenario, in which the TeV cosmic rays (CRs) released at the early stage of this intermediate-age SNR illuminate nearby molecular clouds (MCs). Overwhelming evidence has shown that the northeastern part of the SNR (W28-North) has already encountered the MC clumps. Through this broken shell W28-North, CRs with an energy down to <1 GeV may be able to be injected into nearby MCs. To further verify this hadronic scenario, we first analyze nine years of Fermi-LAT data in/around W28 with energies down to 0.3 GeV. Our Fermi-LAT analysis displays a 10–200 GeV skymap that spatially matches the known TeV sources HESS J1801–233 (W28-North) and HESS J1800–240 A, B, and C (240 A B and C) well. At low energy bands, we have discovered a 0.5–1 GeV blob located to the south of 240 B and C, and a low flux of 0.3–1 GeV at 240 A. A hadronic model is build to explain our analysis results and previous multiwavelength observations of W28. Our model consists of three CR sources: the run-away CRs escaped from a strong shock, the leaked GeV CRs from the broken shell W28-North, and the local CR sea. Through modeling the SNR evolution and the CR acceleration and release, we explain the GeV–TeV emission in/around SNR W28 (except for 240 A) in one model. The damping of the magnetic waves by the neutrals and the decreased acceleration efficiency are both taken into account in our model due to the intermediate age of SNR W28.

Racial/Ethnic and Socio-Contextual Correlates of Chronic Sleep Curtailment in Childhood

PubMed Central

Peña, Michelle-Marie; Rifas-Shiman, Sheryl L.; Gillman, Matthew W.; Redline, Susan; Taveras, Elsie M.

2016-01-01

Study Objectives: To examine the association between race/ethnicity and sleep curtailment from infancy to mid-childhood, and to determine the extent to which socioeconomic and contextual factors both explain racial/ethnic differences and are independently associated with sleep curtailment. Methods: We studied 1,288 children longitudinally in Project Viva, a pre-birth cohort study, from 6 months to 7 years of age. The main exposure was the child's race/ethnicity. The main outcome was a sleep curtailment score from 6 months to 7 years. The score ranged from 0–13, where 0 indicated maximal sleep curtailment and 13 indicated never having curtailed sleep. Results: The mean (standard deviation) sleep curtailment score was 10.2 (2.7) points. In adjusted models (β [95% CI]), black (−1.92, [−2.39, −1.45] points), Hispanic (−1.58, [−2.43, −0.72] points), and Asian (−1.71, [−2.55, −0.86] points) children had lower sleep scores than white children. Adjustment for sociodemographic covariates attenuated racial/ethnic differences in sleep scores for black (by 24%) and Hispanic children (by 32%) but strengthened the differences for Asian children by 14%. Further adjustment for environmental and behavioral variables did not substantially change these differences. Independently, low maternal education, living in households with incomes < $70,000, viewing more TV, and having a TV in the child's bedroom were associated with lower sleep scores. Conclusions: Chronic sleep curtailment from infancy to mid-childhood was more prevalent among black, Hispanic, and Asian children. These differences were partially but not entirely explained by socio-contextual variables. Independently, children from lower socioeconomic status and those with greater exposures to TV also had greater sleep curtailment. Citation: Peña MM, Rifas-Shiman SL, Gillman MW, Redline S, Taveras EM. Racial/ethnic and socio-contextual correlates of chronic sleep curtailment in childhood. SLEEP 2016

Contextually Aided Recovery (CARe): a scientific theory for innate healing.

PubMed

Newell, Dave; Lothe, Lise R; Raven, Timothy J L

2017-01-01

The chiropractic profession emerged when scientific explanations for causes of health and disease were still in infancy and the co-existence of notions such as innate healing and vitalism were perhaps admissible within such a historical context. Notwithstanding, within the scientific culture of the 21 st Century all healthcare paradigms require evidential support which in regard these early concepts are in large part, absent. Nevertheless, a large body of emerging scientific evidence supports the existence of innate healing phenomena that may explain a plethora of clinical outcomes observed during chiropractic care. However, in contrast to the notion that removing the putative subluxation constitutes the mechanism by which this healing is initiated, the evidentially supported explanation is one that invokes the impact of contextual factors inherent in the skilful care and authority of the healthcare provider. This perspective is presented here as the scientific model of Contextually Aided Recovery (CARe). This paper contends that;Contextual effects are powerful and desirable and are triggered by contextual factors present in all therapeutic encounters including those encountered in chiropractic practice.These factors can elicit large clinical effects with substantive evidence supporting pain, immune and motor modulation.The compartmentalisation of specific and non-specific effects is a biologically and scientifically false dichotomy, erroneously invoked to de-legitimise treatment approaches that expertly construct contextual healing scenarios.The use of factors to construct contextual healing scenarios that maximise positive (placebo) and minimize negative (nocebo) effects is a skilful clinical art within the multimodal approach that describes modern chiropractic care and should be presented and defended as a legitimate component of orthodox healthcare Clinical improvement during chiropractic care, beyond any biologically specific treatment effects of manipulation

1. West portal of Tunnel 23, contextual view to northnortheast, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. West portal of Tunnel 23, contextual view to north-northeast, 135mm lens. Camera position is approximately centerline of original Central Pacific Transcontinental line, and bypassed Tunnel '0' (1873) (HAER CA-199) is hidden behind vegetation at center; original line was relocated to present position at right during construction of new line at left in 1909. - Central Pacific Transcontinental Railroad, Tunnel No. 23, Milepost 132.69, Applegate, Placer County, CA

Contextual interference effects on the acquisition of skill and strength of the bench press.

PubMed

Naimo, Marshall A; Zourdos, Michael C; Wilson, Jacob M; Kim, Jeong-Su; Ward, Emery G; Eccles, David W; Panton, Lynn B

2013-06-01

The purpose of this study was to investigate contextual interference effects on skill acquisition and strength gains during the learning of the bench press movement. Twenty-four healthy, college-aged males and females were stratified to control, high contextual interference (HCI), and low contextual interference (LCI) groups. Treatment groups were provided with written and visual instruction on proper bench press form and practiced the bench press and dart throwing for four weeks. Within each session, LCI performed all bench press sets before undertaking dart-throws. HCI undertook dart-throws immediately following each set of bench press. Control only did testing. Measurements, including one repetition maximum (1RM), checklist scores based on video recordings of participants' 1RM's, and dart-throw test scores were taken at pre-test, 1 week, 2 week, post-test, and retention test. Results were consistent with the basic premise of the contextual interference effect. LCI had significant improvements in percent 1RM and checklist scores during training, but were mostly absent after training (post-test and retention test). HCI had significant improvements in percent 1RM and checklist scores both during and after training. Thus, HCI may augment strength and movement skill on the bench press since proper technique is an important component of resistance exercise movements. Copyright © 2013 Elsevier B.V. All rights reserved.

Predicted contextual modulation varies with distance from pinwheel centers in the orientation preference map

PubMed Central

Okamoto, Tsuyoshi; Ikezoe, Koji; Tamura, Hiroshi; Watanabe, Masataka; Aihara, Kazuyuki; Fujita, Ichiro

2011-01-01

In the primary visual cortex (V1) of some mammals, columns of neurons with the full range of orientation preferences converge at the center of a pinwheel-like arrangement, the ‘pinwheel center' (PWC). Because a neuron receives abundant inputs from nearby neurons, the neuron's position on the cortical map likely has a significant impact on its responses to the layout of orientations inside and outside its classical receptive field (CRF). To understand the positional specificity of responses, we constructed a computational model based on orientation preference maps in monkey V1 and hypothetical neuronal connections. The model simulations showed that neurons near PWCs displayed weaker but detectable orientation selectivity within their CRFs, and strongly reduced contextual modulation from extra-CRF stimuli, than neurons distant from PWCs. We suggest that neurons near PWCs robustly extract local orientation within their CRF embedded in visual scenes, and that contextual information is processed in regions distant from PWCs. PMID:22355631

1. West end of Bridge Number 210.52, oblique contextual view ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. West end of Bridge Number 210.52, oblique contextual view to northwest showing the downstream side, 90mm lens. The long trestle approach to the west end of this bridge precluded safe accessibility for axial photography of the west portal. - Southern Pacific Railroad Shasta Route, Bridge No. 210.52, Milepost 210.52, Tehama, Tehama County, CA

Testing conditions in shock-based contextual fear conditioning influence both the behavioral responses and the activation of circuits potentially involved in contextual avoidance.

PubMed

Viellard, Juliette; Baldo, Marcus Vinicius C; Canteras, Newton Sabino

2016-12-15

Previous studies from our group have shown that risk assessment behaviors are the primary contextual fear responses to predatory and social threats, whereas freezing is the main contextual fear response to physically harmful events. To test contextual fear responses to a predator or aggressive conspecific threat, we developed a model that involves placing the animal in an apparatus where it can avoid the threat-associated environment. Conversely, in studies that use shock-based fear conditioning, the animals are usually confined inside the conditioning chamber during the contextual fear test. In the present study, we tested shock-based contextual fear responses using two different behavioral testing conditions: confining the animal in the conditioning chamber or placing the animal in an apparatus with free access to the conditioning compartment. Our results showed that during the contextual fear test, the animals confined to the shock chamber exhibited significantly more freezing. In contrast, the animals that could avoid the conditioning compartment displayed almost no freezing and exhibited risk assessment responses (i.e., crouch-sniff and stretch postures) and burying behavior. In addition, the animals that were able to avoid the shock chamber had increased Fos expression in the juxtadorsomedial lateral hypothalamic area, the dorsomedial part of the dorsal premammillary nucleus and the lateral and dorsomedial parts of the periaqueductal gray, which are elements of a septo/hippocampal-hypothalamic-brainstem circuit that is putatively involved in mediating contextual avoidance. Overall, the present findings show that testing conditions significantly influence both behavioral responses and the activation of circuits involved in contextual avoidance. Copyright © 2016 Elsevier B.V. All rights reserved.

Contextual behavior and neural circuits

PubMed Central

Lee, Inah; Lee, Choong-Hee

2013-01-01

Animals including humans engage in goal-directed behavior flexibly in response to items and their background, which is called contextual behavior in this review. Although the concept of context has long been studied, there are differences among researchers in defining and experimenting with the concept. The current review aims to provide a categorical framework within which not only the neural mechanisms of contextual information processing but also the contextual behavior can be studied in more concrete ways. For this purpose, we categorize contextual behavior into three subcategories as follows by considering the types of interactions among context, item, and response: contextual response selection, contextual item selection, and contextual item–response selection. Contextual response selection refers to the animal emitting different types of responses to the same item depending on the context in the background. Contextual item selection occurs when there are multiple items that need to be chosen in a contextual manner. Finally, when multiple items and multiple contexts are involved, contextual item–response selection takes place whereby the animal either chooses an item or inhibits such a response depending on item–context paired association. The literature suggests that the rhinal cortical regions and the hippocampal formation play key roles in mnemonically categorizing and recognizing contextual representations and the associated items. In addition, it appears that the fronto-striatal cortical loops in connection with the contextual information-processing areas critically control the flexible deployment of adaptive action sets and motor responses for maximizing goals. We suggest that contextual information processing should be investigated in experimental settings where contextual stimuli and resulting behaviors are clearly defined and measurable, considering the dynamic top-down and bottom-up interactions among the neural systems for contextual behavior

Individual and contextual factors related to binge drinking among adolescents in Spain: a multilevel approach.

PubMed

Teixidó-Compañó, Ester; Sordo, Luis; Bosque-Prous, Marina; Puigcorbé, Susanna; Barrio, Gregorio; Brugal, M Teresa; Belza, María José J; Espelt, Albert

2018-01-15

The aim of this study was to estimate the prevalence of binge drinking by regions in Spain and assess the effect of individual and contextual factors related to this drinking pattern in adolescents. A cross-sectional study was performed with data from the 2014 Spanish School Survey on Drug Use (ESTUDES) in students aged 14-18 years (N = 34,259). The outcome was binge drinking in adolescents during the last 30 days. Individual independent variables were socioeconomic variables and variables related to access to alcohol and its availability. Contextual variables consisted of adult alcohol consumption, public policies on alcohol, and socioeconomic factors. Multilevel Poisson regression models with robust variance were estimated, obtaining prevalence ratios (PR) and their 95% confidence intervals.  The results showed that the prevalence of youth binge drinking by region of residence was similar for both sexes (r = 0.72). At the individual level, binge drinking was mainly associated with the perception of easy access to alcohol (PR: 1.38; 95% CI: 1.23-1.55), consumption in open areas [(PR: 3.82; 95% CI: 3.44-4.24) < once a month and (PR: 6.57; 95% CI: 5.85-7.37) ≥ once a month], at least one parent allowing alcohol consumption (PR: 1.42; 95% CI: 1.37-1.47), and receiving >30 euros weekly (PR :1.51; 95% CI: 1.37-1.67). Contextual variables were not associated with youth binge drinking when individual variables were considered. In conclusion, youth binge drinking was associated with individual variables related to high alcohol accessibility and availability, regardless of contextual variables. These variables explained the variability in binge drinking among Spanish regions.

Contextual determinants of induced abortion: a panel analysis.

PubMed

Llorente-Marrón, Mar; Díaz-Fernández, Montserrat; Méndez-Rodríguez, Paz

2016-01-01

Analyze the contextual and individual characteristics that explain the differences in the induced abortion rate, temporally and territorially. We conducted an econometric analysis with panel data of the influence of public investment in health and per capita income on induced abortion as well as a measurement of the effect of social and economic factors related to the labor market and reproduction: female employment, immigration, adolescent fertility and marriage rate. The empirical exercise was conducted with a sample of 22 countries in Europe for the 2001-2009 period. The great territorial variability of induced abortion was the result of contextual and individual socioeconomic factors. Higher levels of national income and investments in public health reduce its incidence. The following sociodemographic characteristics were also significant regressors of induced abortion: female employment, civil status, migration, and adolescent fertility. Induced abortion responds to sociodemographic patterns, in which the characteristics of each country are essential. The individual and contextual socioeconomic inequalities impact significantly on its incidence. Further research on the relationship between economic growth, labor market, institutions and social norms is required to better understand its transnational variability and to reduce its incidence.

Contextual determinants of induced abortion: a panel analysis

PubMed Central

Llorente-Marrón, Mar; Díaz-Fernández, Montserrat; Méndez-Rodríguez, Paz

2016-01-01

ABSTRACT OBJECTIVE Analyze the contextual and individual characteristics that explain the differences in the induced abortion rate, temporally and territorially. METHODS We conducted an econometric analysis with panel data of the influence of public investment in health and per capita income on induced abortion as well as a measurement of the effect of social and economic factors related to the labor market and reproduction: female employment, immigration, adolescent fertility and marriage rate. The empirical exercise was conducted with a sample of 22 countries in Europe for the 2001-2009 period. RESULTS The great territorial variability of induced abortion was the result of contextual and individual socioeconomic factors. Higher levels of national income and investments in public health reduce its incidence. The following sociodemographic characteristics were also significant regressors of induced abortion: female employment, civil status, migration, and adolescent fertility. CONCLUSIONS Induced abortion responds to sociodemographic patterns, in which the characteristics of each country are essential. The individual and contextual socioeconomic inequalities impact significantly on its incidence. Further research on the relationship between economic growth, labor market, institutions and social norms is required to better understand its transnational variability and to reduce its incidence. PMID:27007684

Overexpression of SIRT6 in the hippocampal CA1 impairs the formation of long-term contextual fear memory

PubMed Central

Yin, Xi; Gao, Yuan; Shi, Hai-Shui; Song, Li; Wang, Jie-Chao; Shao, Juan; Geng, Xu-Hong; Xue, Gai; Li, Jian-Li; Hou, Yan-Ning

2016-01-01

Histone modifications have been implicated in learning and memory. Our previous transcriptome data showed that expression of sirtuins 6 (SIRT6), a member of Histone deacetylases (HDACs) family in the hippocampal cornu ammonis 1 (CA1) was decreased after contextual fear conditioning. However, the role of SIRT6 in the formation of memory is still elusive. In the present study, we found that contextual fear conditioning inhibited translational expression of SIRT6 in the CA1. Microinfusion of lentiviral vector-expressing SIRT6 into theCA1 region selectively enhanced the expression of SIRT6 and impaired the formation of long-term contextual fear memory without affecting short-term fear memory. The overexpression of SIRT6 in the CA1 had no effect on anxiety-like behaviors or locomotor activity. Also, we also found that SIRT6 overexpression significantly inhibited the expression of insulin-like factor 2 (IGF2) and amounts of proteins and/or phosphoproteins (e.g. Akt, pAkt, mTOR and p-mTOR) related to the IGF2 signal pathway in the CA1. These results demonstrate that the overexpression of SIRT6 in the CA1 impaired the formation of long-term fear memory, and SIRT6 in the CA1 may negatively modulate the formation of contextual fear memory via inhibiting the IGF signaling pathway. PMID:26732053

Region segmentation and contextual cuing in visual search.

PubMed

Conci, Markus; von Mühlenen, Adrian

2009-10-01

Contextual information provides an important source for behavioral orienting. For instance, in the contextual-cuing paradigm, repetitions of the spatial layout of elements in a search display can guide attention to the target location. The present study explored how this contextual-cuing effect is influenced by the grouping of search elements. In Experiment 1, four nontarget items could be arranged collinearly to form an imaginary square. The presence of such a square eliminated the contextual-cuing effect, despite the fact that the square's location still had a predictive value for the target location. Three follow-up experiments demonstrated that other types of grouping abolished contextual cuing in a similar way and that the mere presence of a task-irrelevant singleton had only a diminishing effect (by half) on contextual cuing. These findings suggest that a segmented, salient region can interfere with contextual cuing, reducing its predictive impact on search.

Cotinine enhances the extinction of contextual fear memory and reduces anxiety after fear conditioning.

PubMed

Zeitlin, Ross; Patel, Sagar; Solomon, Rosalynn; Tran, John; Weeber, Edwin J; Echeverria, Valentina

2012-03-17

Posttraumatic stress disorder (PTSD) is an anxiety disorder triggered by traumatic events. Symptoms include anxiety, depression and deficits in fear memory extinction (FE). PTSD patients show a higher prevalence of cigarette smoking than the general population. The present study investigated the effects of cotinine, a tobacco-derived compound, over anxiety and contextual fear memory after fear conditioning (FC) in mice, a model for inducing PTSD-like symptoms. Two-month-old C57BL/6J mice were separated into three experimental groups. These groups were used to investigate the effect of pretreatment with cotinine on contextual fear memory and posttreatment on extinction and stability or retrievability of the fear memory. Also, changes induced by cotinine on the expression of extracellular signal-regulated kinase (ERK)1/2 were assessed after extinction in the hippocampus. An increase in anxiety and corticosterone levels were found after fear conditioning. Cotinine did not affect corticosterone levels but enhanced the extinction of contextual fear, decreased anxiety and the stability and/or retrievability of contextual fear memory. Cotinine-treated mice showed higher levels of the active forms of ERK1/2 than vehicle-treated mice after FC. This evidence suggests that cotinine is a potential new pharmacological treatment to reduce symptoms in individuals with PTSD. Published by Elsevier B.V.

Pigeons exhibit contextual cueing to both simple and complex backgrounds.

PubMed

Wasserman, Edward A; Teng, Yuejia; Castro, Leyre

2014-05-01

Repeated pairings of a particular visual context with a specific location of a target stimulus facilitate target search in humans. We explored an animal model of this contextual cueing effect using a novel Cueing-Miscueing design. Pigeons had to peck a target which could appear in one of four possible locations on four possible color backgrounds or four possible color photographs of real-world scenes. On 80% of the trials, each of the contexts was uniquely paired with one of the target locations; on the other 20% of the trials, each of the contexts was randomly paired with the remaining target locations. Pigeons came to exhibit robust contextual cueing when the context preceded the target by 2s, with reaction times to the target being shorter on correctly-cued trials than on incorrectly-cued trials. Contextual cueing proved to be more robust with photographic backgrounds than with uniformly colored backgrounds. In addition, during the context-target delay, pigeons predominately pecked toward the location of the upcoming target, suggesting that attentional guidance contributes to contextual cueing. These findings confirm the effectiveness of animal models of contextual cueing and underscore the important part played by associative learning in producing the effect. This article is part of a Special Issue entitled: SQAB 2013: Contextual Con. Copyright © 2014 Elsevier B.V. All rights reserved.

Towards explaining the health impacts of residential energy efficiency interventions - A realist review. Part 1: Pathways.

PubMed

Willand, Nicola; Ridley, Ian; Maller, Cecily

2015-05-01

This paper is Part 1 of a realist review that tries to explain the impacts of residential energy efficiency interventions (REEIs) on householder health. According to recent systematic reviews residential energy efficiency interventions may benefit health. It is argued that home energy improvement are complex interventions and that a better understanding of the latent mechanisms and contextual issues that may shape the outcome of interventions is needed for effective intervention design. This realist review synthesises the results of 28 energy efficiency improvement programmes. This first part provides a review of the explanatory factors of the three key pathways, namely warmth in the home, affordability of fuel and psycho-social factors, and the pitfall of inadequate indoor air quality. The review revealed that REEIs improved winter warmth and lowered relative humidity with benefits for cardiovascular and respiratory health. In addition, residential energy efficiency improvements consolidated the meaning of the home as a safe haven, strengthened the householder's perceived autonomy and enhanced social status. Although satisfaction with the home proved to be an important explanation for positive mental health outcomes, financial considerations seemed to have played a secondary role. Evidence for negative impacts was rare but the risk should not be dismissed. Comprehensive refurbishments were not necessarily more effective than thermal retrofits or upgrades. A common protocol for the quantitative and qualitative evaluation of interventions would facilitate the synthesis of future studies. Householder and contextual influences are addressed in Part 2. Copyright © 2015 Elsevier Ltd. All rights reserved.

Network model of top-down influences on local gain and contextual interactions in visual cortex.

PubMed

Piëch, Valentin; Li, Wu; Reeke, George N; Gilbert, Charles D

2013-10-22

The visual system uses continuity as a cue for grouping oriented line segments that define object boundaries in complex visual scenes. Many studies support the idea that long-range intrinsic horizontal connections in early visual cortex contribute to this grouping. Top-down influences in primary visual cortex (V1) play an important role in the processes of contour integration and perceptual saliency, with contour-related responses being task dependent. This suggests an interaction between recurrent inputs to V1 and intrinsic connections within V1 that enables V1 neurons to respond differently under different conditions. We created a network model that simulates parametrically the control of local gain by hypothetical top-down modification of local recurrence. These local gain changes, as a consequence of network dynamics in our model, enable modulation of contextual interactions in a task-dependent manner. Our model displays contour-related facilitation of neuronal responses and differential foreground vs. background responses over the neuronal ensemble, accounting for the perceptual pop-out of salient contours. It quantitatively reproduces the results of single-unit recording experiments in V1, highlighting salient contours and replicating the time course of contextual influences. We show by means of phase-plane analysis that the model operates stably even in the presence of large inputs. Our model shows how a simple form of top-down modulation of the effective connectivity of intrinsic cortical connections among biophysically realistic neurons can account for some of the response changes seen in perceptual learning and task switching.

Implicit motives, explicit traits, and task and contextual performance at work.

PubMed

Lang, Jonas W B; Zettler, Ingo; Ewen, Christian; Hülsheger, Ute R

2012-11-01

Personality psychologists have long argued that explicit traits (as measured by questionnaires) channel the expression of implicit motives (as measured by coding imaginative verbal behavior) such that both interact in the prediction of relevant life outcome variables. In the present research, we apply these ideas in the context of industrial and organizational psychology and propose that 2 explicit traits work as channels for the expression of 3 core implicit motives in task and contextual job performance (extraversion for implicit affiliation and implicit power; explicit achievement for implicit achievement). As a test of these theoretical ideas, we report a study in which employees (N = 241) filled out a questionnaire booklet and worked on an improved modern implicit motive measure, the operant motive test. Their supervisors rated their task and contextual performance. Results support 4 of the 6 theoretical predictions and show that interactions between implicit motives and explicit traits increase the explained criterion variance in both task and contextual performance. (c) 2012 APA, all rights reserved.

1. West portal of Tunnel 3, contextual view to north ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. West portal of Tunnel 3, contextual view to north from milepost 537.6, 210mm lens. The single-lens searchlight-type block signals are Southern Pacific Common Standard signals, a type in use since the 1920s. Many of these have been replaced system-wide as a result of various mergers since the 1980s. Located in the Diamond Peak Wilderness of Willamette National Forest, Tunnel 3 passes beneath Pengra Pass. - Southern Pacific Railroad Natron Cutoff, Tunnel 3, Milepost 537.77, Odell Lake, Klamath County, OR

A Contextual Fire Detection Algorithm for Simulated HJ-1B Imagery.

PubMed

Qian, Yonggang; Yan, Guangjian; Duan, Sibo; Kong, Xiangsheng

2009-01-01

The HJ-1B satellite, which was launched on September 6, 2008, is one of the small ones placed in the constellation for disaster prediction and monitoring. HJ-1B imagery was simulated in this paper, which contains fires of various sizes and temperatures in a wide range of terrestrial biomes and climates, including RED, NIR, MIR and TIR channels. Based on the MODIS version 4 contextual algorithm and the characteristics of HJ-1B sensor, a contextual fire detection algorithm was proposed and tested using simulated HJ-1B data. It was evaluated by the probability of fire detection and false alarm as functions of fire temperature and fire area. Results indicate that when the simulated fire area is larger than 45 m(2) and the simulated fire temperature is larger than 800 K, the algorithm has a higher probability of detection. But if the simulated fire area is smaller than 10 m(2), only when the simulated fire temperature is larger than 900 K, may the fire be detected. For fire areas about 100 m(2), the proposed algorithm has a higher detection probability than that of the MODIS product. Finally, the omission and commission error were evaluated which are important factors to affect the performance of this algorithm. It has been demonstrated that HJ-1B satellite data are much sensitive to smaller and cooler fires than MODIS or AVHRR data and the improved capabilities of HJ-1B data will offer a fine opportunity for the fire detection.

A Contextual Fire Detection Algorithm for Simulated HJ-1B Imagery

PubMed Central

Qian, Yonggang; Yan, Guangjian; Duan, Sibo; Kong, Xiangsheng

2009-01-01

The HJ-1B satellite, which was launched on September 6, 2008, is one of the small ones placed in the constellation for disaster prediction and monitoring. HJ-1B imagery was simulated in this paper, which contains fires of various sizes and temperatures in a wide range of terrestrial biomes and climates, including RED, NIR, MIR and TIR channels. Based on the MODIS version 4 contextual algorithm and the characteristics of HJ-1B sensor, a contextual fire detection algorithm was proposed and tested using simulated HJ-1B data. It was evaluated by the probability of fire detection and false alarm as functions of fire temperature and fire area. Results indicate that when the simulated fire area is larger than 45 m2 and the simulated fire temperature is larger than 800 K, the algorithm has a higher probability of detection. But if the simulated fire area is smaller than 10 m2, only when the simulated fire temperature is larger than 900 K, may the fire be detected. For fire areas about 100 m2, the proposed algorithm has a higher detection probability than that of the MODIS product. Finally, the omission and commission error were evaluated which are important factors to affect the performance of this algorithm. It has been demonstrated that HJ-1B satellite data are much sensitive to smaller and cooler fires than MODIS or AVHRR data and the improved capabilities of HJ-1B data will offer a fine opportunity for the fire detection. PMID:22399950

Neural responses in the macaque v1 to bar stimuli with various lengths presented on the blind spot.

PubMed

Matsumoto, Masayuki; Komatsu, Hidehiko

2005-05-01

Although there is no retinal input within the blind spot, it is filled with the same visual attributes as its surround. Earlier studies showed that neural responses are evoked at the retinotopic representation of the blind spot in the primary visual cortex (V1) when perceptual filling-in of a surface or completion of a bar occurs. To determine whether these neural responses correlate with perception, we recorded from V1 neurons whose receptive fields overlapped the blind spot. Bar stimuli of various lengths were presented at the blind spots of monkeys while they performed a fixation task. One end of the bar was fixed at a position outside the blind spot, and the position of the other end was varied. Perceived bar length was measured using a similar set of bar stimuli in human subjects. As long as one end of the bar was inside the blind spot, the perceived bar length remained constant, and when the bar exceeded the blind spot, perceptual completion occurred, and the perceived bar length increased substantially. Some V1 neurons of the monkey exhibited a significant increase in their activity when the bar exceeded the blind spot, even though the amount of the retinal stimulation increased only slightly. These response increases coincided with perceptual completion observed in human subjects and were much larger than would be expected from simple spatial summation and could not be explained by contextual modulation. We conclude that the completed bar appearing on the part of the receptive field embedded within the blind spot gave rise to the observed increase in neuronal activity.

Local hidden-variable model for a recent experimental test of quantum nonlocality and local contextuality

NASA Astrophysics Data System (ADS)

La Cour, Brian R.

2017-07-01

An experiment has recently been performed to demonstrate quantum nonlocality by establishing contextuality in one of a pair of photons encoding four qubits; however, low detection efficiencies and use of the fair-sampling hypothesis leave these results open to possible criticism due to the detection loophole. In this Letter, a physically motivated local hidden-variable model is considered as a possible mechanism for explaining the experimentally observed results. The model, though not intrinsically contextual, acquires this quality upon post-selection of coincident detections.

Empathy and contextual social cognition.

PubMed

Melloni, Margherita; Lopez, Vladimir; Ibanez, Agustin

2014-03-01

Empathy is a highly flexible and adaptive process that allows for the interplay of prosocial behavior in many different social contexts. Empathy appears to be a very situated cognitive process, embedded with specific contextual cues that trigger different automatic and controlled responses. In this review, we summarize relevant evidence regarding social context modulation of empathy for pain. Several contextual factors, such as stimulus reality and personal experience, affectively link with other factors, emotional cues, threat information, group membership, and attitudes toward others to influence the affective, sensorimotor, and cognitive processing of empathy. Thus, we propose that the frontoinsular-temporal network, the so-called social context network model (SCNM), is recruited during the contextual processing of empathy. This network would (1) update the contextual cues and use them to construct fast predictions (frontal regions), (2) coordinate the internal (body) and external milieus (insula), and (3) consolidate the context-target associative learning of empathic processes (temporal sites). Furthermore, we propose these context-dependent effects of empathy in the framework of the frontoinsular-temporal network and examine the behavioral and neural evidence of three neuropsychiatric conditions (Asperger syndrome, schizophrenia, and the behavioral variant of frontotemporal dementia), which simultaneously present with empathy and contextual integration impairments. We suggest potential advantages of a situated approach to empathy in the assessment of these neuropsychiatric disorders, as well as their relationship with the SCNM.

Semantic contextual cuing and visual attention.

PubMed

Goujon, Annabelle; Didierjean, André; Marmèche, Evelyne

2009-02-01

Since M. M. Chun and Y. Jiang's (1998) original study, a large body of research based on the contextual cuing paradigm has shown that the visuocognitive system is capable of capturing certain regularities in the environment in an implicit way. The present study investigated whether regularities based on the semantic category membership of the context can be learned implicitly and whether that learning depends on attention. The contextual cuing paradigm was used with lexical displays in which the semantic category of the contextual words either did or did not predict the target location. Experiments 1 and 2 revealed that implicit contextual cuing effects can be extended to semantic category regularities. Experiments 3 and 4 indicated an implicit contextual cuing effect when the predictive context appeared in an attended color but not when the predictive context appeared in an ignored color. However, when the previously ignored context suddenly became attended, it immediately facilitated performance. In contrast, when the previously attended context suddenly became ignored, no benefit was observed. Results suggest that the expression of implicit semantic knowledge depends on attention but that latent learning can nevertheless take place outside the attentional field. Copyright 2009 APA, all rights reserved.

Oxytocin receptor antagonist atosiban impairs consolidation, but not reconsolidation of contextual fear memory in rats.

PubMed

Abdullahi, Payman Rasise; Eskandarian, Sharaf; Ghanbari, Ali; Rashidy-Pour, Ali

2018-05-23

There is increasing evidence that oxytocin is involved in learning and memory process. This study investigated the effects of blockade of oxytocin receptors using the selective oxytocin receptor antagonist atosiban (ATO) on contextual fear memory consolidation and reconsolidation in male rats. Post-training injections of different doses of ATO (1, 10, 100 or 1000 µg/kg) impaired the 48 h retention performance in a dose-dependent manner. The same doses of ATO following memory reactivation did not impair subsequent expression of contextual fear memories which formed under low or high shock intensities and tested 24 h or one week following memory reactivation. Also, no effect was found when ATO was administrated in the absence of memory reactivation. Our finding is the first report that indicates endogenous oxytocin released during training play an important role in the consolidation, but not reconsolidation of contextual fear memory in rats. Copyright © 2018. Published by Elsevier B.V.

Long-term adaptation to change in implicit contextual learning.

PubMed

Zellin, Martina; von Mühlenen, Adrian; Müller, Hermann J; Conci, Markus

2014-08-01

The visual world consists of spatial regularities that are acquired through experience in order to guide attentional orienting. For instance, in visual search, detection of a target is faster when a layout of nontarget items is encountered repeatedly, suggesting that learned contextual associations can guide attention (contextual cuing). However, scene layouts sometimes change, requiring observers to adapt previous memory representations. Here, we investigated the long-term dynamics of contextual adaptation after a permanent change of the target location. We observed fast and reliable learning of initial context-target associations after just three repetitions. However, adaptation of acquired contextual representations to relocated targets was slow and effortful, requiring 3 days of training with overall 80 repetitions. A final test 1 week later revealed equivalent effects of contextual cuing for both target locations, and these were comparable to the effects observed on day 1. That is, observers learned both initial target locations and relocated targets, given extensive training combined with extended periods of consolidation. Thus, while implicit contextual learning efficiently extracts statistical regularities of our environment at first, it is rather insensitive to change in the longer term, especially when subtle changes in context-target associations need to be acquired.

1. Contextual view to west of the Southern Pacific Railroad ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Contextual view to west of the Southern Pacific Railroad Carlin Shops buildings at Carlin, Nevada. Visible beneath the pedestrian bridge are the Engine Stores Building (HAER NV-26-A) left, Oil House (HAER NV-26-B) left center, and Roundhouse Machine Shop Extension (HAER NV-26-C) center background. The work train cars at right consist of the Boom Tender normally coupled to the wrecking crane and over which the crane's boom hung during travel, and a former Harriman standard-design Railway Post Office car (90mm lens). - Southern Pacific Railroad, Carlin Shops, Foot of Sixth Street, Carlin, Elko County, NV

Scene-Based Contextual Cueing in Pigeons

PubMed Central

Wasserman, Edward A.; Teng, Yuejia; Brooks, Daniel I.

2014-01-01

Repeated pairings of a particular visual context with a specific location of a target stimulus facilitate target search in humans. We explored an animal model of such contextual cueing. Pigeons had to peck a target which could appear in one of four locations on color photographs of real-world scenes. On half of the trials, each of four scenes was consistently paired with one of four possible target locations; on the other half of the trials, each of four different scenes was randomly paired with the same four possible target locations. In Experiments 1 and 2, pigeons exhibited robust contextual cueing when the context preceded the target by 1 s to 8 s, with reaction times to the target being shorter on predictive-scene trials than on random-scene trials. Pigeons also responded more frequently during the delay on predictive-scene trials than on random-scene trials; indeed, during the delay on predictive-scene trials, pigeons predominately pecked toward the location of the upcoming target, suggesting that attentional guidance contributes to contextual cueing. In Experiment 3, involving left-right and top-bottom scene reversals, pigeons exhibited stronger control by global than by local scene cues. These results attest to the robustness and associative basis of contextual cueing in pigeons. PMID:25546098

Effects of normal aging on memory for multiple contextual features.

PubMed

Gagnon, Sylvain; Soulard, Kathleen; Brasgold, Melissa; Kreller, Joshua

2007-08-01

Twenty-four younger (18-35 years) and 24 older adult participants (65 or older) were exposed to three experimental conditions involving the memorization words and their associated contextual features, with contextual feature complexity increasing from Conditions 1 to 3. In Condition 1, words presented varied only on one binary feature (color, size, or character), while in Conditions 2 and 3, words presented varied on two and three binary features, respectively. Each condition was carried out as follows: (1) learning of a word list; (2) encoding of words and their contextual features; (3) delay; and (4) memory for contextual features through a discrimination task. Results indicated that young adults discriminated more features than older adults on all conditions. In both age groups, contextual feature discrimination accuracy decreased as the number of features increased. Moreover, older adults demonstrated near floor performance when tested with two or more binary features. We conclude that increasing context complexity strains attentional resources.

The influence of group membership on cross-contextual imitation.

PubMed

Genschow, Oliver; Schindler, Simon

2016-08-01

Research on mimicry has demonstrated that individuals imitate in-group members more strongly than out-group members. In the present study, we tested whether such top-down modulation also applies for more extreme forms of direct mapping, such as for cross-contextual imitation settings, in which individuals imitate others' movements without sharing a common goal or context. Models on self-other control suggest that top-down modulations are based merely on a direct link between social sensory processing and imitation. That is, perceived similarities between oneself and another person is sufficient to amplify a shared representation between own and others' actions, which then trigger imitation. However, motivational accounts explain such findings with the assumption that individuals are motivated to affiliate with others. Because imitation is linked to positive social consequences, individuals should imitate in-group members more strongly than out-group members. We tested these two theoretical accounts against each other by applying a cross-contextual imitation paradigm. The results demonstrate that in-group members are more strongly cross-contextually imitated than out-group members the higher individuals' motivation to affiliate with the in-group is. This supports motivational models but not self-other control accounts. Further theoretical implications are discussed.

Investigating implicit statistical learning mechanisms through contextual cueing.

PubMed

Goujon, Annabelle; Didierjean, André; Thorpe, Simon

2015-09-01

Since its inception, the contextual cueing (CC) paradigm has generated considerable interest in various fields of cognitive sciences because it constitutes an elegant approach to understanding how statistical learning (SL) mechanisms can detect contextual regularities during a visual search. In this article we review and discuss five aspects of CC: (i) the implicit nature of learning, (ii) the mechanisms involved in CC, (iii) the mediating factors affecting CC, (iv) the generalization of CC phenomena, and (v) the dissociation between implicit and explicit CC phenomena. The findings suggest that implicit SL is an inherent component of ongoing processing which operates through clustering, associative, and reinforcement processes at various levels of sensory-motor processing, and might result from simple spike-timing-dependent plasticity. Copyright © 2015 Elsevier Ltd. All rights reserved.

1. West portal of Snowshed 29, contextual view to east, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. West portal of Snowshed 29, contextual view to east, 135mm lens. This is perhaps the last section of timber snowshed on this line. Integral with the east end of Tunnel 41, Snowshed 29 provides protection leading to the west portal of the tunnel. The snowshed today consists of (west to east) 199 feet of timber type T4 shed built in 1954, 365 feet of timber type T7 built in 1954, 85 feet of timber type T1 built in 1951, four feet of timber type T7 built in 1925 concurrent with Tunnel 41, and 41 feet of recent prefabricated concrete panel shed. - Central Pacific Transcontinental Railroad, Tunnel No. 41, Milepost 193.3, Donner, Placer County, CA

Dopamine D1-like receptor in lateral habenula nucleus affects contextual fear memory and long-term potentiation in hippocampal CA1 in rats.

PubMed

Chan, Jiangping; Guan, Xin; Ni, Yiling; Luo, Lilu; Yang, Liqiang; Zhang, Pengyue; Zhang, Jichuan; Chen, Yanmei

2017-03-15

The Lateral Habenula (LHb) plays an important role in emotion and cognition. Recent experiments suggest that LHb has functional interaction with the hippocampus and plays an important role in spatial learning. LHb is reciprocally connected with midbrain monoaminergic brain areas such as the ventral tegmental area (VTA). However, the role of dopamine type 1 receptor (D1R) in LHb in learning and memory is not clear yet. In the present study, D1R agonist or antagonist were administered bilaterally into the LHb in rats. We found that both D1R agonist and antagonist impaired the acquisition of contextual fear memory in rats. D1R agonist or antagonist also impaired long term potentiation (LTP) in hippocampal CA3-CA1 synapses in freely moving rats and attenuated learning induced phosphorylation of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) subunit 1 (GluA1) at Ser831 and Ser845 in hippocampus. Taken together, our results suggested that dysfunction of D1R in LHb affected the function of hippocampus. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluative conditioning of positive and negative valence affects P1 and N1 in verbal processing.

PubMed

Kuchinke, Lars; Fritsch, Nathalie; Müller, Christina J

2015-10-22

The present study examined the effect of contextual learning on the neural processing of previously meaningless pseudowords. During an evaluative conditioning session on 5 consecutive days, participants learned to associate 120 pseudowords with either positive, neutral or negative pictures. In a second session, participants were presented all conditioned pseudowords again together with 40 new pseudowords in a recognition memory task while their event-related potentials (ERPs) were recorded. The behavioral data confirm successful learning of pseudoword valence. At the neural level, early modulations of the ERPs are visible at the P1 and the N1 components discriminating between positively and negatively conditioned pseudowords. Differences to new pseudowords were visible at later processing stages as indicated by modulations of the LPC. These results support a contextual learning hypothesis that is able to explain very early emotional ERP modulations in visual word recognition. Source localization indicates a role of medial-frontal brain regions as a likely origin of these early valence discrimination signals which are discussed to promote top-down signals to sensory processing. Copyright © 2015. Published by Elsevier B.V.

Extreme variability among mammalian V1R gene families.

PubMed

Young, Janet M; Massa, Hillary F; Hsu, Li; Trask, Barbara J

2010-01-01

We report an evolutionary analysis of the V1R gene family across 37 mammalian genomes. V1Rs comprise one of three chemosensory receptor families expressed in the vomeronasal organ, and contribute to pheromone detection. We first demonstrate that Trace Archive data can be used effectively to determine V1R family sizes and to obtain sequences of most V1R family members. Analyses of V1R sequences from trace data and genome assemblies show that species-specific expansions previously observed in only eight species were prevalent throughout mammalian evolution, resulting in "semi-private" V1R repertoires for most mammals. The largest families are found in mouse and platypus, whose V1R repertoires have been published previously, followed by mouse lemur and rabbit (approximately 215 and approximately 160 intact V1Rs, respectively). In contrast, two bat species and dolphin possess no functional V1Rs, only pseudogenes, and suffered inactivating mutations in the vomeronasal signal transduction gene Trpc2. We show that primate V1R decline happened prior to acquisition of trichromatic vision, earlier during evolution than was previously thought. We also show that it is extremely unlikely that decline of the dog V1R repertoire occurred in response to selective pressures imposed by humans during domestication. Functional repertoire sizes in each species correlate roughly with anatomical observations of vomeronasal organ size and quality; however, no single ecological correlate explains the very diverse fates of this gene family in different mammalian genomes. V1Rs provide one of the most extreme examples observed to date of massive gene duplication in some genomes, with loss of all functional genes in other species.

Semantic Relationships between Contextual Synonyms

ERIC Educational Resources Information Center

Zeng, Xian-mo

2007-01-01

Contextual synonym is a linguistic phenomenon often applied but rarely discussed. This paper is to discuss the semantic relationships between contextual synonyms and the requirements under which words can be used as contextual synonyms between each other. The three basic relationships are embedment, intersection and non-coherence. The requirements…

Understanding and Interpreting Japanese NP1 "wa" NP2 "da" Sentences: Mechanism and Contextual Factors

ERIC Educational Resources Information Center

Yoshida, Megumi

2013-01-01

This dissertation investigates the contextual factors that affect the understanding and interpretation of one Japanese topicalized construction, NP[subscript 1] wa NP[subscript 2] da sentences, by native speakers of Japanese. The construction allows two possibilities in the relation between the NP[subscript 1] and the NP[subscript 2]. When the two…

The influence of contextual diversity on eye movements in reading.

PubMed

Plummer, Patrick; Perea, Manuel; Rayner, Keith

2014-01-01

Recent research has shown contextual diversity (i.e., the number of passages in which a given word appears) to be a reliable predictor of word processing difficulty. It has also been demonstrated that word-frequency has little or no effect on word recognition speed when accounting for contextual diversity in isolated word processing tasks. An eye-movement experiment was conducted wherein the effects of word-frequency and contextual diversity were directly contrasted in a normal sentence reading scenario. Subjects read sentences with embedded target words that varied in word-frequency and contextual diversity. All 1st-pass and later reading times were significantly longer for words with lower contextual diversity compared to words with higher contextual diversity when controlling for word-frequency and other important lexical properties. Furthermore, there was no difference in reading times for higher frequency and lower frequency words when controlling for contextual diversity. The results confirm prior findings regarding contextual diversity and word-frequency effects and demonstrate that contextual diversity is a more accurate predictor of word processing speed than word-frequency within a normal reading task. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

Capturing contextual effects in spectro-temporal receptive fields.

PubMed

Westö, Johan; May, Patrick J C

2016-09-01

Spectro-temporal receptive fields (STRFs) are thought to provide descriptive images of the computations performed by neurons along the auditory pathway. However, their validity can be questioned because they rely on a set of assumptions that are probably not fulfilled by real neurons exhibiting contextual effects, that is, nonlinear interactions in the time or frequency dimension that cannot be described with a linear filter. We used a novel approach to investigate how a variety of contextual effects, due to facilitating nonlinear interactions and synaptic depression, affect different STRF models, and if these effects can be captured with a context field (CF). Contextual effects were incorporated in simulated networks of spiking neurons, allowing one to define the true STRFs of the neurons. This, in turn, made it possible to evaluate the performance of each STRF model by comparing the estimations with the true STRFs. We found that currently used STRF models are particularly poor at estimating inhibitory regions. Specifically, contextual effects make estimated STRFs dependent on stimulus density in a contrasting fashion: inhibitory regions are underestimated at lower densities while artificial inhibitory regions emerge at higher densities. The CF was found to provide a solution to this dilemma, but only when it is used together with a generalized linear model. Our results therefore highlight the limitations of the traditional STRF approach and provide useful recipes for how different STRF models and stimuli can be used to arrive at reliable quantifications of neural computations in the presence of contextual effects. The results therefore push the purpose of STRF analysis from simply finding an optimal stimulus toward describing context-dependent computations of neurons along the auditory pathway. Copyright © 2016 Elsevier B.V. All rights reserved.

Contextual Variability in Free Recall

ERIC Educational Resources Information Center

Lohnas, Lynn J.; Polyn, Sean M.; Kahana, Michael J.

2011-01-01

According to contextual-variability theory, experiences encoded at different times tend to be associated with different contextual states. The gradual evolution of context implies that spaced items will be associated with more distinct contextual states, and thus have more unique retrieval cues, than items presented in proximity. Ross and Landauer…

Does contextual cuing guide the deployment of attention?

PubMed

Kunar, Melina A; Flusberg, Stephen; Horowitz, Todd S; Wolfe, Jeremy M

2007-08-01

Contextual cuing experiments show that when displays are repeated, reaction times to find a target decrease over time even when observers are not aware of the repetition. It has been thought that the context of the display guides attention to the target. The authors tested this hypothesis by comparing the effects of guidance in a standard search task with the effects of contextual cuing. First, in standard search, an improvement in guidance causes search slopes (derived from Reaction Time x Set Size functions) to decrease. In contrast, the authors found that search slopes in contextual cuing did not become more efficient over time (Experiment 1). Second, when guidance was optimal (e.g., in easy feature search), they still found a small but reliable contextual cuing effect (Experiments 2a and 2b), suggesting that other factors, such as response selection, contribute to the effect. Experiment 3 supported this hypothesis by showing that the contextual cuing effect disappeared when the authors added interference to the response selection process. Overall, the data suggest that the relationship between guidance and contextual cuing is weak and that response selection can account for part of the effect. (c) 2007 APA, all rights reserved

Does Contextual Cueing Guide the Deployment of Attention?

PubMed Central

Kunar, Melina A.; Flusberg, Stephen; Horowitz, Todd S.; Wolfe, Jeremy M.

2008-01-01

Contextual cueing experiments show that when displays are repeated, reaction times (RTs) to find a target decrease over time even when observers are not aware of the repetition. It has been thought that the context of the display guides attention to the target. We tested this hypothesis by comparing the effects of guidance in a standard search task to the effects of contextual cueing. Firstly, in standard search, an improvement in guidance causes search slopes (derived from RT × Set Size functions) to decrease. In contrast, we found that search slopes in contextual cueing did not become more efficient over time (Experiment 1). Secondly, when guidance is optimal (e.g. in easy feature search) we still found a small, but reliable contextual cueing effect (Experiments 2a and 2b), suggesting that other factors, such as response selection, contribute to the effect. Experiment 3 supported this hypothesis by showing that the contextual cueing effect disappeared when we added interference to the response selection process. Overall, our data suggest that the relationship between guidance and contextual cueing is weak and that response selection can account for part of the effect. PMID:17683230

Contextual Cueing Effects Across the Lifespan

PubMed Central

MERRILL, EDWARD C.; CONNERS, FRANCES A.; ROSKOS, BEVERLY; KLINGER, MARK R.; KLINGER, LAURA GROFER

2018-01-01

The authors evaluated age-related variations in contextual cueing, which reflects the extent to which visuospatial regularities can facilitate search for a target. Previous research produced inconsistent results regarding contextual cueing effects in young children and in older adults, and no study has investigated the phenomenon across the life span. Three groups (6, 20, and 70 years old) were compared. Participants located a designated target stimulus embedded in a context of distractor stimuli. During exposure, the location of the target could be predicted from the location of the distracters in each display. During test, these predictable displays were intermixed with new displays that did not predict the target location. Response times to locating predictable relative to unpredictable targets were compared. All groups exhibited facilitation effects greater than 0 (95% CIs [.02, .11], d = .4; [.01, .12], d = .4; and [.01, .10], d = .4, for the children, young adults, and older adults, respectively) indicating that contextual cueing is robust across a wide age range. The relative magnitude of contextual cueing effects was essentially identical across the age range tested, F(2, 103) = 1.71,ηρ2 = .02. The authors argue that a mechanism that uses environmental covariation is available to all age ranges, but the expression of the contextual cueing may depend on the way it is measured. PMID:23991612

Graph-theoretic strengths of contextuality

NASA Astrophysics Data System (ADS)

de Silva, Nadish

2017-03-01

Cabello-Severini-Winter and Abramsky-Hardy (building on the framework of Abramsky-Brandenburger) both provide classes of Bell and contextuality inequalities for very general experimental scenarios using vastly different mathematical techniques. We review both approaches, carefully detail the links between them, and give simple, graph-theoretic methods for finding inequality-free proofs of nonlocality and contextuality and for finding states exhibiting strong nonlocality and/or contextuality. Finally, we apply these methods to concrete examples in stabilizer quantum mechanics relevant to understanding contextuality as a resource in quantum computation.

TRPC3 channels critically regulate hippocampal excitability and contextual fear memory.

PubMed

Neuner, Sarah M; Wilmott, Lynda A; Hope, Kevin A; Hoffmann, Brian; Chong, Jayhong A; Abramowitz, Joel; Birnbaumer, Lutz; O'Connell, Kristen M; Tryba, Andrew K; Greene, Andrew S; Savio Chan, C; Kaczorowski, Catherine C

2015-03-15

Memory formation requires de novo protein synthesis, and memory disorders may result from misregulated synthesis of critical proteins that remain largely unidentified. Plasma membrane ion channels and receptors are likely candidates given their role in regulating neuron excitability, a candidate memory mechanism. Here we conduct targeted molecular monitoring and quantitation of hippocampal plasma membrane proteins from mice with intact or impaired contextual fear memory to identify putative candidates. Here we report contextual fear memory deficits correspond to increased Trpc3 gene and protein expression, and demonstrate TRPC3 regulates hippocampal neuron excitability associated with memory function. These data provide a mechanistic explanation for enhanced contextual fear memory reported herein following knockdown of TRPC3 in hippocampus. Collectively, TRPC3 modulates memory and may be a feasible target to enhance memory and treat memory disorders. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

High-resolution infrared studies of the v 10, v 11, v 14, and v 18 levels of [1.1.1]propellane

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

Kirkpatrick, Robynne W.; Masiello, Tony; Martin, Matthew A.

2012-11-15

This paper is a continuation of earlier work for which the high resolution infrared spectrum of [1.1.1]propellane was measured and its k and l structure resolved for the first time. Here we present results from an analysis of more than 16,000 transitions involving three fundamental bands v 10 (E'-A1'), v 11 (E'-A1'), v 14 (A2''-A1') and two difference bands (v 10- v 18) (E'-E'') and (v 11-v 18) (E'-E"). Additional information about v18 was also obtained from the difference band (v 15+v 18)-v 18 (E'-E") and the binary combination band (v 15+v 18) (E'-A1'). Through the use of the groundmore » state constants reported in an earlier paper [1], rovibrational constants have been determined for all the vibrational states involved in these bands. The rovibrational parameters for the v 18(E'') state were obtained from combination-differences and showed no need to include interactions with other states. The v 10(E') state analysis was also straight-forward, with only a weak Coriolis interaction with the levels of the v 14(A2'') state. The latter levels are much more affected by a strong Coriolis interaction with the levels of the nearby v 11(E') state and also by a small but significant interaction with another state, presumably the v16(E'') state, that is not directly observed. Gaussian calculations (B3LYP/cc-pVTZ) computed at the anharmonic level aided the analyses by providing initial values for many of the parameters. These theoretical results generally compare favorably with the final parameter values deduced from the spectral analyses. Finally, evidence was obtained for several level crossings between the rotational levels of the v 11 and v 14 states and, using a weak coupling term corresponding to a Δk = ±5, Δl = ∓1 matrix element, it was possible to find transitions from the ground state that, combined with transitions to the same upper state, give a value of C 0 = 0.1936519(4) cm -1. This result, combined with the value of B 0 = 0.28755833(14) cm-1 reported

Interaction between scene-based and array-based contextual cueing.

PubMed

Rosenbaum, Gail M; Jiang, Yuhong V

2013-07-01

Contextual cueing refers to the cueing of spatial attention by repeated spatial context. Previous studies have demonstrated distinctive properties of contextual cueing by background scenes and by an array of search items. Whereas scene-based contextual cueing reflects explicit learning of the scene-target association, array-based contextual cueing is supported primarily by implicit learning. In this study, we investigated the interaction between scene-based and array-based contextual cueing. Participants searched for a target that was predicted by both the background scene and the locations of distractor items. We tested three possible patterns of interaction: (1) The scene and the array could be learned independently, in which case cueing should be expressed even when only one cue was preserved; (2) the scene and array could be learned jointly, in which case cueing should occur only when both cues were preserved; (3) overshadowing might occur, in which case learning of the stronger cue should preclude learning of the weaker cue. In several experiments, we manipulated the nature of the contextual cues present during training and testing. We also tested explicit awareness of scenes, scene-target associations, and arrays. The results supported the overshadowing account: Specifically, scene-based contextual cueing precluded array-based contextual cueing when both were predictive of the location of a search target. We suggest that explicit, endogenous cues dominate over implicit cues in guiding spatial attention.

Effects of whole body (56)Fe radiation on contextual freezing and Arc-positive cells in the dentate gyrus.

PubMed

Raber, Jacob; Allen, Antiño R; Rosi, Susanna; Sharma, Sourabh; Dayger, Catherine; Davis, Matthew J; Fike, John R

2013-06-01

The space radiation environment contains high-energy charged particles such as (56)Fe, which could pose a significant hazard to hippocampal function in astronauts during and after the mission(s). The mechanisms underlying impairments in cognition are not clear but might involve alterations in the percentage of neurons in the dentate gyrus expressing the plasticity-related immediate early gene Arc. Previously, we showed effects of cranial (56)Fe irradiation on hippocampus-dependent contextual freezing and on the percentage of Arc-positive cells in the enclosed, but not free, blade. Because it is unclear whether whole body (56)Fe irradiation causes similar effects on these markers of hippocampal function, in the present study we quantified the effects of whole body (56)Fe irradiation (600MeV, 0.5 or 1Gy) on hippocampus-dependent and hippocampus-independent cognitive performance and determined whether these effects were associated with changes in Arc expression in the enclosed and free blades of the dentate gyrus. Whole body (56)Fe irradiation impacted contextual but not cued fear freezing and the percentage of Arc-positive cells in the enclosed and free blades. In mice tested for contextual freezing, there was a correlation between Arc-positive cells in the enclosed and free blades. In addition, in mice irradiated with 0.5Gy, contextual freezing in the absence of aversive stimuli correlated with the percentage of Arc-positive cells in the enclosed blade. In mice tested for cued freezing, there was no correlation between Arc-positive cells in the enclosed and free blades. In contrast, cued freezing in the presence or absence of aversive stimuli correlated with Arc-positive cells in the free blade. In addition, in mice irradiated with 1Gy cued freezing in the absence of aversive stimuli correlated with the percentage of Arc-positive neurons in the free blade. These data indicate that while whole body (56)Fe radiation affects contextual freezing and Arc-positive cells

Extinction of Contextual Cocaine Memories Requires Cav1.2 within D1R-Expressing Cells and Recruits Hippocampal Cav1.2-Dependent Signaling Mechanisms

PubMed Central

Lee, Anni S.; Fischer, Delaney K.; Van Kempen, Tracey A.; Mudragel, Vladimir; Glass, Michael J.

2017-01-01

Exposure to cocaine-associated contextual cues contributes significantly to relapse. Extinction of these contextual associations, which involves a new form of learning, reduces cocaine-seeking behavior; however, the molecular mechanisms underlying this process remain largely unknown. We report that extinction, but not acquisition, of cocaine conditioned place preference (CPP) in male mice increased Cav1.2 L-type Ca2+ channel mRNA and protein in postsynaptic density (PSD) fractions of the hippocampus, a brain region involved in drug–context associations. Moreover, viral-mediated deletion of Cav1.2 in the dorsal hippocampus attenuated extinction of cocaine CPP. Molecular studies examining downstream Cav1.2 targets revealed that extinction recruited calcium/calmodulin (Ca2+/CaMK)-dependent protein kinase II (CaMKII) to the hippocampal PSD. This occurred in parallel with an increase in phosphorylation of the AMPA GluA1 receptor subunit at serine 831 (S831), a CaMKII site, along with an increase in total PSD GluA1. The necessity of S831 GluA1 was further demonstrated by the lack of extinction in S831A GluA1 phosphomutant mice. Of note hippocampal GluA1 levels remained unaltered at the PSD, but were reduced near the PSD and at perisynaptic sites of dendritic spines in extinction-resistant S831A mutant mice. Finally, conditional knock-out of Cav1.2 in dopamine D1 receptor (D1R)-expressing cells resulted in attenuation of cocaine CPP extinction and lack of extinction-dependent changes in hippocampal PSD CaMKII expression and S831 GluA1 phosphorylation. In summary, we demonstrate an essential role for the hippocampal Cav1.2/CaMKII/S831 GluA1 pathway in cocaine CPP extinction, with data supporting contribution of hippocampal D1R-expressing cells in this process. These findings demonstrate a novel role for Cav1.2 channels in extinction of contextual cocaine-associated memories. SIGNIFICANCE STATEMENT Continued drug-seeking behavior, a defining characteristic of cocaine

Prostaglandins are necessary and sufficient to induce contextual fear learning impairments after interleukin-1 beta injections into the dorsal hippocampus

PubMed Central

Hein, A.M.; Stutzman, D.L.; Bland, S.T.; Barrientos, R.M.; Watkins, L.R.; Rudy, J.W.; Maier, S.F.

2008-01-01

The intra-hippocampal administration of interleukin-1β (IL-1β) as well as the induction of elevated but physiological levels of IL-1β within the hippocampus interferes with the formation of long-term memory. There is evidence suggesting that the induction of prostaglandin (PG) formation by IL-1β is involved in impairments in working and spatial memory following IL-1β. The present experiments extend these findings by showing that PGs are responsible for memory deficits in contextual fear conditioning that occur following IL-1β injection into the dorsal hippocampus. Cyclooxygenase (COX) inhibition blocked the disruption in contextual fear conditioning produced by IL-1β and COX inhibition alone also disrupted contextual memory, suggesting an inverted U-shaped relationship between PG levels and memory. In addition to demonstrating the necessity of PGs in IL-1β mediated memory deficits, we also show that PGs injected directly into the dorsal hippocampus are sufficient to impair context memory and significantly reduce post-conditioning levels of BDNF within the hippocampus, suggesting a possible mechanism for the memory-impairing effects of PGs. PMID:18035502

Temporal and peripheral extraction of contextual cues from scenes during visual search.

PubMed

Koehler, Kathryn; Eckstein, Miguel P

2017-02-01

Scene context is known to facilitate object recognition and guide visual search, but little work has focused on isolating image-based cues and evaluating their contributions to eye movement guidance and search performance. Here, we explore three types of contextual cues (a co-occurring object, the configuration of other objects, and the superordinate category of background elements) and assess their joint contributions to search performance in the framework of cue-combination and the temporal unfolding of their extraction. We also assess whether observers' ability to extract each contextual cue in the visual periphery is a bottleneck that determines the utilization and contribution of each cue to search guidance and decision accuracy. We find that during the first four fixations of a visual search task observers first utilize the configuration of objects for coarse eye movement guidance and later use co-occurring object information for finer guidance. In the absence of contextual cues, observers were suboptimally biased to report the target object as being absent. The presence of the co-occurring object was the only contextual cue that had a significant effect in reducing decision bias. The early influence of object-based cues on eye movements is corroborated by a clear demonstration of observers' ability to extract object cues up to 16° into the visual periphery. The joint contributions of the cues to decision search accuracy approximates that expected from the combination of statistically independent cues and optimal cue combination. Finally, the lack of utilization and contribution of the background-based contextual cue to search guidance cannot be explained by the availability of the contextual cue in the visual periphery; instead it is related to background cues providing the least inherent information about the precise location of the target in the scene.

Textural-Contextual Labeling and Metadata Generation for Remote Sensing Applications

NASA Technical Reports Server (NTRS)

Kiang, Richard K.

1999-01-01

Despite the extensive research and the advent of several new information technologies in the last three decades, machine labeling of ground categories using remotely sensed data has not become a routine process. Considerable amount of human intervention is needed to achieve a level of acceptable labeling accuracy. A number of fundamental reasons may explain why machine labeling has not become automatic. In addition, there may be shortcomings in the methodology for labeling ground categories. The spatial information of a pixel, whether textural or contextual, relates a pixel to its surroundings. This information should be utilized to improve the performance of machine labeling of ground categories. Landsat-4 Thematic Mapper (TM) data taken in July 1982 over an area in the vicinity of Washington, D.C. are used in this study. On-line texture extraction by neural networks may not be the most efficient way to incorporate textural information into the labeling process. Texture features are pre-computed from cooccurrence matrices and then combined with a pixel's spectral and contextual information as the input to a neural network. The improvement in labeling accuracy with spatial information included is significant. The prospect of automatic generation of metadata consisting of ground categories, textural and contextual information is discussed.

Contextual cuing: the effects of stimulus variation, intentionality, and aging.

PubMed

Lyon, John; Scialfa, Charles; Cordazzo, Scheila; Bubric, Katherine

2014-06-01

Three experiments investigated the generalisation of contextual cuing and whether the effect is incidental or intentional in nature. Experiment 1 assessed contextual cuing across variations in display contrast, homogeneity, and spatial separation. Cuing effects were found with all display types and reaction-time disruption was manifested for repeated displays when consistent configurations had their target locations altered. Recognition memory for repeated displays was at chance levels. Experiment 2 showed that contextual cuing was insensitive to instructions to search for and remember repeated displays. Experiment 2A found that there were no age differences in contextual cuing or effects of intentional instructions, and no memory for repeated displays. Future research questions concern the generalisation of contextual cuing to a wider variety of display conditions and naturalistic tasks.

Contextual fear conditioning depresses infralimbic excitability.

PubMed

Soler-Cedeño, Omar; Cruz, Emmanuel; Criado-Marrero, Marangelie; Porter, James T

2016-04-01

Patients with posttraumatic stress disorder (PTSD) show hypo-active ventromedial prefrontal cortices (vmPFC) that correlate with their impaired ability to discriminate between safe and dangerous contexts and cues. Previously, we found that auditory fear conditioning depresses the excitability of neurons populating the homologous structure in rodents, the infralimbic cortex (IL). However, it is undetermined if IL depression was mediated by the cued or contextual information. The objective of this study was to examine whether contextual information was sufficient to depress IL neuronal excitability. After exposing rats to context-alone, pseudoconditioning, or contextual fear conditioning, we used whole-cell current-clamp recordings to examine the excitability of IL neurons in prefrontal brain slices. We found that contextual fear conditioning reduced IL neuronal firing in response to depolarizing current steps. In addition, neurons from contextual fear conditioned animals showed increased slow afterhyperpolarization potentials (sAHPs). Moreover, the observed changes in IL excitability correlated with contextual fear expression, suggesting that IL depression may contribute to the encoding of contextual fear. Copyright © 2016 Elsevier Inc. All rights reserved.

Hierarchical acquisition of visual specificity in spatial contextual cueing.

PubMed

Lie, Kin-Pou

2015-01-01

Spatial contextual cueing refers to visual search performance's being improved when invariant associations between target locations and distractor spatial configurations are learned incidentally. Using the instance theory of automatization and the reverse hierarchy theory of visual perceptual learning, this study explores the acquisition of visual specificity in spatial contextual cueing. Two experiments in which detailed visual features were irrelevant for distinguishing between spatial contexts found that spatial contextual cueing was visually generic in difficult trials when the trials were not preceded by easy trials (Experiment 1) but that spatial contextual cueing progressed to visual specificity when difficult trials were preceded by easy trials (Experiment 2). These findings support reverse hierarchy theory, which predicts that even when detailed visual features are irrelevant for distinguishing between spatial contexts, spatial contextual cueing can progress to visual specificity if the stimuli remain constant, the task is difficult, and difficult trials are preceded by easy trials. However, these findings are inconsistent with instance theory, which predicts that when detailed visual features are irrelevant for distinguishing between spatial contexts, spatial contextual cueing will not progress to visual specificity. This study concludes that the acquisition of visual specificity in spatial contextual cueing is more plausibly hierarchical, rather than instance-based.

[Evaluation of Contextual Factors in Psychosomatic Rehabilitation].

PubMed

Bülau, N I; Kessemeier, F; Petermann, F; Bassler, M; Kobelt, A

2016-12-01

Objectives: Although individualized and ICF-oriented implementation of rehabilitation treatment requires knowledge of relevant contextual factors, there is a lack of operationalized documentation and measurement tools to evaluate these factors. Therefore, an ICF-oriented semi-structured interview was designed. Methods: 20 contextual factors were externally assessed whether they negatively affected mental functioning and participation of psychosomatic patients. Additionally, psychometric scales were applied. Results: Six relevant impairing contextual factors were identified. Contextual factors significantly correlated with psychometric scales. Patients with higher contextual impairment showed significantly higher psychological stress levels. Conclusions: Anamnesis of contextual factors at the beginning of psychosomatic rehabilitation yields important information for therapy planning. Further research on contextual factors in medical rehabilitation is needed. © Georg Thieme Verlag KG Stuttgart · New York.

Contextualizing symbol, symbolizing context

NASA Astrophysics Data System (ADS)

Maudy, Septiani Yugni; Suryadi, Didi; Mulyana, Endang

2017-08-01

When students learn algebra for the first time, inevitably they are experiencing transition from arithmetic to algebraic thinking. Once students could apprehend this essential mathematical knowledge, they are cultivating their ability in solving daily life problems by applying algebra. However, as we dig into this transitional stage, we identified possible students' learning obstacles to be dealt with seriously in order to forestall subsequent hindrance in studying more advance algebra. We come to realize this recurring problem as we undertook the processes of re-personalization and re-contextualization in which we scrutinize the very basic questions: 1) what is variable, linear equation with one variable and their relationship with the arithmetic-algebraic thinking? 2) Why student should learn such concepts? 3) How to teach those concepts to students? By positioning ourselves as a seventh grade student, we address the possibility of children to think arithmetically when confronted with the problems of linear equation with one variable. To help them thinking algebraically, Bruner's modes of representation developed contextually from concrete to abstract were delivered to enhance their interpretation toward the idea of variables. Hence, from the outset we designed the context for student to think symbolically initiated by exploring various symbols that could be contextualized in order to bridge student traversing the arithmetic-algebraic fruitfully.

A More Efficient Contextuality Distillation Protocol

NASA Astrophysics Data System (ADS)

Meng, Hui-xian; Cao, Huai-xin; Wang, Wen-hua; Fan, Ya-jing; Chen, Liang

2018-03-01

Based on the fact that both nonlocality and contextuality are resource theories, it is natural to ask how to amplify them more efficiently. In this paper, we present a contextuality distillation protocol which produces an n-cycle box B ∗ B ' from two given n-cycle boxes B and B '. It works efficiently for a class of contextual n-cycle ( n ≥ 4) boxes which we termed as "the generalized correlated contextual n-cycle boxes". For any two generalized correlated contextual n-cycle boxes B and B ', B ∗ B ' is more contextual than both B and B '. Moreover, they can be distilled toward to the maximally contextual box C H n as the times of iteration goes to infinity. Among the known protocols, our protocol has the strongest approximate ability and is optimal in terms of its distillation rate. What is worth noting is that our protocol can witness a larger set of nonlocal boxes that make communication complexity trivial than the protocol in Brunner and Skrzypczyk (Phys. Rev. Lett. 102, 160403 2009), this might be helpful for exploring the problem that why quantum nonlocality is limited.

A More Efficient Contextuality Distillation Protocol

NASA Astrophysics Data System (ADS)

Meng, Hui-xian; Cao, Huai-xin; Wang, Wen-hua; Fan, Ya-jing; Chen, Liang

2017-12-01

Based on the fact that both nonlocality and contextuality are resource theories, it is natural to ask how to amplify them more efficiently. In this paper, we present a contextuality distillation protocol which produces an n-cycle box B ∗ B ' from two given n-cycle boxes B and B '. It works efficiently for a class of contextual n-cycle (n ≥ 4) boxes which we termed as "the generalized correlated contextual n-cycle boxes". For any two generalized correlated contextual n-cycle boxes B and B ', B ∗ B ' is more contextual than both B and B '. Moreover, they can be distilled toward to the maximally contextual box C H n as the times of iteration goes to infinity. Among the known protocols, our protocol has the strongest approximate ability and is optimal in terms of its distillation rate. What is worth noting is that our protocol can witness a larger set of nonlocal boxes that make communication complexity trivial than the protocol in Brunner and Skrzypczyk (Phys. Rev. Lett. 102, 160403 2009), this might be helpful for exploring the problem that why quantum nonlocality is limited.

Effects of Normal Aging on Memory for Multiple Contextual Features

ERIC Educational Resources Information Center

Gagnon, Sylvain; Soulard, Kathleen; Brasgold, Melissa; Kreller, Joshua

2007-01-01

Twenty-four younger (18-35 years) and 24 older adult participants (65 or older) were exposed to three experimental conditions involving the memorization words and their associated contextual features, with contextual feature complexity increasing from Conditions 1 to 3. In Condition 1, words presented varied only on one binary feature (color,…

Different implications of the dorsal and ventral hippocampus on contextual memory retrieval after stress.

PubMed

Pierard, C; Dorey, R; Henkous, N; Mons, N; Béracochéa, D

2017-09-01

This study assessed the relative contributions of dorsal (dHPC) and ventral (vHPC) hippocampus regions in mediating the rapid effects of an acute stress on contextual memory retrieval. Indeed, we previously showed that an acute stress (3 electric footschocks; 0.9 mA each) delivered 15 min before the 24 h-test inversed the memory retrieval pattern in a contextual discrimination task. Specifically, mice learned in a four-hole board two successive discriminations (D1 and D2) varying by the color and texture of the floor. Twenty-four hours later, nonstressed animals remembered accurately D1 but not D2 whereas stressed mice showed an opposite memory retrieval pattern, D2 being more accurately remembered than D1. We showed here that, at the time of memory testing in that task, stressed animals exhibited no significant changes neither in pCREB activity nor in the time-course evolution of corticosterone into the vHPC; in contrast, a significant decrease in pCREB activity and a significant increase in corticosterone were observed in the dHPC as compared to nonstressed mice. Moreover, local infusion of the anesthetic lidocaine into the vHPC 15 min before the onset of the stressor did not modify the memory retrieval pattern in nonstress and stress conditions whereas lidocaine infusion into the dHPC induced in nonstressed mice an memory retrieval pattern similar to that observed in stressed animals. The overall set of data shows that memory retrieval in nonstress condition involved primarily the dHPC and that the inversion of memory retrieval pattern after stress is linked to a dHPC but not vHPC dysfunction. © 2017 Wiley Periodicals, Inc.

Contextual sensitivity in scientific reproducibility

PubMed Central

Van Bavel, Jay J.; Mende-Siedlecki, Peter; Brady, William J.; Reinero, Diego A.

2016-01-01

In recent years, scientists have paid increasing attention to reproducibility. For example, the Reproducibility Project, a large-scale replication attempt of 100 studies published in top psychology journals found that only 39% could be unambiguously reproduced. There is a growing consensus among scientists that the lack of reproducibility in psychology and other fields stems from various methodological factors, including low statistical power, researcher’s degrees of freedom, and an emphasis on publishing surprising positive results. However, there is a contentious debate about the extent to which failures to reproduce certain results might also reflect contextual differences (often termed “hidden moderators”) between the original research and the replication attempt. Although psychologists have found extensive evidence that contextual factors alter behavior, some have argued that context is unlikely to influence the results of direct replications precisely because these studies use the same methods as those used in the original research. To help resolve this debate, we recoded the 100 original studies from the Reproducibility Project on the extent to which the research topic of each study was contextually sensitive. Results suggested that the contextual sensitivity of the research topic was associated with replication success, even after statistically adjusting for several methodological characteristics (e.g., statistical power, effect size). The association between contextual sensitivity and replication success did not differ across psychological subdisciplines. These results suggest that researchers, replicators, and consumers should be mindful of contextual factors that might influence a psychological process. We offer several guidelines for dealing with contextual sensitivity in reproducibility. PMID:27217556

Contextual sensitivity in scientific reproducibility.

PubMed

Van Bavel, Jay J; Mende-Siedlecki, Peter; Brady, William J; Reinero, Diego A

2016-06-07

In recent years, scientists have paid increasing attention to reproducibility. For example, the Reproducibility Project, a large-scale replication attempt of 100 studies published in top psychology journals found that only 39% could be unambiguously reproduced. There is a growing consensus among scientists that the lack of reproducibility in psychology and other fields stems from various methodological factors, including low statistical power, researcher's degrees of freedom, and an emphasis on publishing surprising positive results. However, there is a contentious debate about the extent to which failures to reproduce certain results might also reflect contextual differences (often termed "hidden moderators") between the original research and the replication attempt. Although psychologists have found extensive evidence that contextual factors alter behavior, some have argued that context is unlikely to influence the results of direct replications precisely because these studies use the same methods as those used in the original research. To help resolve this debate, we recoded the 100 original studies from the Reproducibility Project on the extent to which the research topic of each study was contextually sensitive. Results suggested that the contextual sensitivity of the research topic was associated with replication success, even after statistically adjusting for several methodological characteristics (e.g., statistical power, effect size). The association between contextual sensitivity and replication success did not differ across psychological subdisciplines. These results suggest that researchers, replicators, and consumers should be mindful of contextual factors that might influence a psychological process. We offer several guidelines for dealing with contextual sensitivity in reproducibility.

Contextual control using a go/no-go procedure with compound abstract stimuli.

PubMed

Modenesi, Rafael Diego; Debert, Paula

2015-05-01

Contextual control has been described as (1) a five-term contingency, in which the contextual stimulus exerts conditional control over conditional discriminations, and (2) allowing one stimulus to be a member of different equivalence classes without merging them into one. Matching-to-sample is the most commonly employed procedure to produce and study contextual control. The present study evaluated whether the go/no-go procedure with compound stimuli produces equivalence classes that share stimuli. This procedure does not allow the identification of specific stimulus functions (e.g., contextual, conditional, or discriminative functions). If equivalence classes were established with this procedure, then only the latter part of the contextual control definition (2) would be met. Six undergraduate students participated in the present study. In the training phases, responses to AC, BD, and XY compounds with stimuli from the same classes were reinforced, and responses to AC, BD, and XY compounds with stimuli from different classes were not. In addition, responses to X1A1B1, X1A2B2, X2A1B2, and X2A2B1 compounds were reinforced and responses to the other combinations were not. During the tests, the participants had to respond to new combinations of stimuli compounds YCD to indicate the formation of four equivalence classes that share stimuli: X1A1B1Y1C1D1, X1A2B2Y1C2D2, X2A1B2Y2C1D2, and X2A2B1Y2C2D1. Four of the six participants showed the establishment of these classes. These results indicate that establishing contextual stimulus functions is unnecessary to produce equivalence classes that share stimuli. Therefore, these results are inconsistent with the first part of the definition of contextual control. © Society for the Experimental Analysis of Behavior.

Distinct Contributions of Median Raphe Nucleus to Contextual Fear Conditioning and Fear-Potentiated Startle

PubMed Central

Silva, R. C. B.; Cruz, A. P. M.; Avanzi, V.; Landeira-Fernandez, J.; Brandão, M. L.

2002-01-01

Ascending 5-HT projections from the median raphe nucleus (MRN), probably to the hippocampus, are implicated in the acquisition of contextual fear (background stimuli), as assessed by freezing behavior. Foreground cues like light, used as a conditioned stimulus (CS) in classical fear conditioning, also cause freezing through thalamic transmission to the amygdala. As the MRN projects to the hippocampus and amygdala, the role of this raphe nucleus in fear conditioning to explicit cues remains to be explained. Here we analyzed the behavior of rats with MRN electrolytic lesions in a contextual conditioning situation and in a fear-potentiated startle procedure. The animals received MRN electrolytic lesions either before or on the day after two consecutive training sessions in which they were submitted to 10 conditioning trials, each in an experimental chamber (same context) where they. received foot-shocks (0.6 mA, 1 sec) paired to a 4-sec light CS. Seven to ten days later, the animals were submitted to testing sessions for assessing conditioned fear when they were placed for five shocks, and the duration of contextual freezing was recorded. The animals were then submitted to a fear-potentiated startle in response to a 4-sec light-CS, followed by white noise (100 dB, 50 ms). Control rats (sham) tested in the same context showed more freezing than did rats with pre- or post-training MRN lesions. Startle was clearly potentiated in the presence of light CS in the sham-lesioned animals. Whereas pretraining lesions reduced both freezing and fear-potentiated startle, the post-training lesions reduced only freezing to context, without changing the fear-potentiated startle. In a second experiment, neurotoxic lesions of the MRN with local injections of N-methyl-D-aspartate or the activation of 5-HT1A somatodendritic auto-receptors of the MRN by microinjections of the 5-HT1A receptor agonist 8-hydroxy- 2-(di-n-propylamino)tetralin (8-OH-DPAT) before the training sessions also

The Personal and Contextual Contributors to School Belongingness among Primary School Students

PubMed Central

Vaz, Sharmila; Falkmer, Marita; Ciccarelli, Marina; Passmore, Anne; Parsons, Richard; Tan, Tele; Falkmer, Torbjorn

2015-01-01

School belongingness has gained currency among educators and school health professionals as an important determinant of adolescent health. The current cross-sectional study presents the 15 most significant personal and contextual factors that collectively explain 66.4% (two-thirds) of the variability in 12-year old students’ perceptions of belongingness in primary school. The study is part of a larger longitudinal study investigating the factors associated with student adjustment in the transition from primary to secondary school. The study found that girls and students with disabilities had higher school belongingness scores than boys, and their typically developing counterparts respectively; and explained 2.5% of the variability in school belongingness. The majority (47.1% out of 66.4%) of the variability in school belongingness was explained by student personal factors, such as social acceptance, physical appearance competence, coping skills, and social affiliation motivation; followed by parental expectations (3% out of 66.4%), and school-based factors (13.9% out of 66.4%) such as, classroom involvement, task-goal structure, autonomy provision, cultural pluralism, and absence of bullying. Each of the identified contributors of primary school belongingness can be shaped through interventions, system changes, or policy reforms. PMID:25876074

Acidosis Differentially Modulates Inactivation in NaV1.2, NaV1.4, and NaV1.5 Channels

PubMed Central

Vilin, Yury Y.; Peters, Colin H.; Ruben, Peter C.

2012-01-01

NaV channels play a crucial role in neuronal and muscle excitability. Using whole-cell recordings we studied effects of low extracellular pH on the biophysical properties of NaV1.2, NaV1.4, and NaV1.5, expressed in cultured mammalian cells. Low pH produced different effects on different channel subtypes. Whereas NaV1.4 exhibited very low sensitivity to acidosis, primarily limited to partial block of macroscopic currents, the effects of low pH on gating in NaV1.2 and NaV1.5 were profound. In NaV1.2 low pH reduced apparent valence of steady-state fast inactivation, shifted the τ(V) to depolarizing potentials and decreased channels availability during onset to slow and use-dependent inactivation (UDI). In contrast, low pH delayed open-state inactivation in NaV1.5, right-shifted the voltage-dependence of window current, and increased channel availability during onset to slow and UDI. These results suggest that protons affect channel availability in an isoform-specific manner. A computer model incorporating these results demonstrates their effects on membrane excitability. PMID:22701426

The time course of attentional deployment in contextual cueing.

PubMed

Jiang, Yuhong V; Sigstad, Heather M; Swallow, Khena M

2013-04-01

The time course of attention is a major characteristic on which different types of attention diverge. In addition to explicit goals and salient stimuli, spatial attention is influenced by past experience. In contextual cueing, behaviorally relevant stimuli are more quickly found when they appear in a spatial context that has previously been encountered than when they appear in a new context. In this study, we investigated the time that it takes for contextual cueing to develop following the onset of search layout cues. In three experiments, participants searched for a T target in an array of Ls. Each array was consistently associated with a single target location. In a testing phase, we manipulated the stimulus onset asynchrony (SOA) between the repeated spatial layout and the search display. Contextual cueing was equivalent for a wide range of SOAs between 0 and 1,000 ms. The lack of an increase in contextual cueing with increasing cue durations suggests that as an implicit learning mechanism, contextual cueing cannot be effectively used until search begins.

Contextual Influences on Children's Mental Health and School Performance: The Moderating Effects of Family Immigrant Status

ERIC Educational Resources Information Center

Georgiades, Katholiki; Boyle, Michael H.; Duku, Eric

2007-01-01

Data from a nationally representative sample of 13,470 children aged 4-11 years were used to study contextual influences on children's mental health and school performance, the moderating effects of family immigrant status and underlying family processes that might explain these relationships. Despite greater socioeconomic disadvantage, children…

SModelS v1.1 user manual: Improving simplified model constraints with efficiency maps

NASA Astrophysics Data System (ADS)

Ambrogi, Federico; Kraml, Sabine; Kulkarni, Suchita; Laa, Ursula; Lessa, Andre; Magerl, Veronika; Sonneveld, Jory; Traub, Michael; Waltenberger, Wolfgang

2018-06-01

SModelS is an automatized tool for the interpretation of simplified model results from the LHC. It allows to decompose models of new physics obeying a Z2 symmetry into simplified model components, and to compare these against a large database of experimental results. The first release of SModelS, v1.0, used only cross section upper limit maps provided by the experimental collaborations. In this new release, v1.1, we extend the functionality of SModelS to efficiency maps. This increases the constraining power of the software, as efficiency maps allow to combine contributions to the same signal region from different simplified models. Other new features of version 1.1 include likelihood and χ2 calculations, extended information on the topology coverage, an extended database of experimental results as well as major speed upgrades for both the code and the database. We describe in detail the concepts and procedures used in SModelS v1.1, explaining in particular how upper limits and efficiency map results are dealt with in parallel. Detailed instructions for code usage are also provided.

Post-training gamma irradiation-enhanced contextual fear memory associated with reduced neuronal activation of the infralimbic cortex.

PubMed

Kugelman, Tara; Zuloaga, Damian G; Weber, Sydney; Raber, Jacob

2016-02-01

The brain might be exposed to irradiation under a variety of situations, including clinical treatments, nuclear accidents, dirty bomb scenarios, and military and space missions. Correctly recalling tasks learned prior to irradiation is important but little is known about post-learning effects of irradiation. It is not clear whether exposure to X-ray irradiation during memory consolidation, a few hours following training, is associated with altered contextual fear conditioning 24h after irradiation and which brain region(s) might be involved in these effects. Brain immunoreactivity patterns of the immediately early gene c-Fos, a marker of cellular activity was used to determine which brain areas might be altered in post-training irradiation memory retention tasks. In this study, we show that post-training gamma irradiation exposure (1 Gy) enhanced contextual fear memory 24h later and is associated with reduced cellular activation in the infralimbic cortex. Reduced GABA-ergic neurotransmission in parvalbumin-positive cells in the infralimbic cortex might play a role in this post-training radiation-enhanced contextual fear memory. Copyright © 2015 Elsevier B.V. All rights reserved.

Multilevel Mediation: Cumulative Contextual Risk, Maternal Differential Treatment, and Children's Behavior within Families

ERIC Educational Resources Information Center

Meunier, Jean Christophe; Boyle, Michael; O'Connor, Thomas G.; Jenkins, Jennifer M.

2013-01-01

This study tests the hypothesis that links between contextual risk and children's outcomes are partially explained by differential parenting. Using multi-informant measurement and including up to four children per family (M[subscript age] = 3.51, SD = 2.38) in a sample of 397 families, indirect effects (through maternal differential…

Activity of the anterior cingulate cortex and ventral hippocampus underlie increases in contextual fear generalization.

PubMed

Cullen, Patrick K; Gilman, T Lee; Winiecki, Patrick; Riccio, David C; Jasnow, Aaron M

2015-10-01

Memories for context become less specific with time resulting in animals generalizing fear from training contexts to novel contexts. Though much attention has been given to the neural structures that underlie the long-term consolidation of a context fear memory, very little is known about the mechanisms responsible for the increase in fear generalization that occurs as the memory ages. Here, we examine the neural pattern of activation underlying the expression of a generalized context fear memory in male C57BL/6J mice. Animals were context fear conditioned and tested for fear in either the training context or a novel context at recent and remote time points. Animals were sacrificed and fluorescent in situ hybridization was performed to assay neural activation. Our results demonstrate activity of the prelimbic, infralimbic, and anterior cingulate (ACC) cortices as well as the ventral hippocampus (vHPC) underlie expression of a generalized fear memory. To verify the involvement of the ACC and vHPC in the expression of a generalized fear memory, animals were context fear conditioned and infused with 4% lidocaine into the ACC, dHPC, or vHPC prior to retrieval to temporarily inactivate these structures. The results demonstrate that activity of the ACC and vHPC is required for the expression of a generalized fear memory, as inactivation of these regions returned the memory to a contextually precise form. Current theories of time-dependent generalization of contextual memories do not predict involvement of the vHPC. Our data suggest a novel role of this region in generalized memory, which should be incorporated into current theories of time-dependent memory generalization. We also show that the dorsal hippocampus plays a prolonged role in contextually precise memories. Our findings suggest a possible interaction between the ACC and vHPC controls the expression of fear generalization. Copyright © 2015 Elsevier Inc. All rights reserved.

Strong Recurrent Networks Compute the Orientation-Tuning of Surround Modulation in Primate V1

PubMed Central

Shushruth, S.; Mangapathy, Pradeep; Ichida, Jennifer M.; Bressloff, Paul C.; Schwabe, Lars; Angelucci, Alessandra

2012-01-01

In macaque primary visual cortex (V1) neuronal responses to stimuli inside the receptive field (RF) are modulated by stimuli in the RF surround. This modulation is orientation-specific. Previous studies suggested that for some cells this specificity may not be fixed, but changes with the stimulus orientation presented to the RF. We demonstrate, in recording studies, that this tuning behavior is instead highly prevalent in V1 and, in theoretical work, that it arises only if V1 operates in a regime of strong local recurrence. Strongest surround suppression occurs when the stimuli in the RF and the surround are iso-oriented, and strongest facilitation when the stimuli are cross-oriented. This is the case even when the RF is sub-optimally activated by a stimulus of non-preferred orientation, but only if this stimulus can activate the cell when presented alone. This tuning behavior emerges from the interaction of lateral inhibition (via the surround pathways), which is tuned to the RF’s preferred orientation, with weakly-tuned, but strong, local recurrent connections, causing maximal withdrawal of recurrent excitation at the feedforward input orientation. Thus, horizontal and feedback modulation of strong recurrent circuits allows the tuning of contextual effects to change with changing feedforward inputs. PMID:22219292

Contextual Cueing Effect in Spatial Layout Defined by Binocular Disparity

PubMed Central

Zhao, Guang; Zhuang, Qian; Ma, Jie; Tu, Shen; Liu, Qiang; Sun, Hong-jin

2017-01-01

Repeated visual context induces higher search efficiency, revealing a contextual cueing effect, which depends on the association between the target and its visual context. In this study, participants performed a visual search task where search items were presented with depth information defined by binocular disparity. When the 3-dimensional (3D) configurations were repeated over blocks, the contextual cueing effect was obtained (Experiment 1). When depth information was in chaos over repeated configurations, visual search was not facilitated and the contextual cueing effect largely crippled (Experiment 2). However, when we made the search items within a tiny random displacement in the 2-dimentional (2D) plane but maintained the depth information constant, the contextual cueing was preserved (Experiment 3). We concluded that the contextual cueing effect was robust in the context provided by 3D space with stereoscopic information, and more importantly, the visual system prioritized stereoscopic information in learning of spatial information when depth information was available. PMID:28912739

Contextual Cueing Effect in Spatial Layout Defined by Binocular Disparity.

PubMed

Zhao, Guang; Zhuang, Qian; Ma, Jie; Tu, Shen; Liu, Qiang; Sun, Hong-Jin

2017-01-01

Repeated visual context induces higher search efficiency, revealing a contextual cueing effect, which depends on the association between the target and its visual context. In this study, participants performed a visual search task where search items were presented with depth information defined by binocular disparity. When the 3-dimensional (3D) configurations were repeated over blocks, the contextual cueing effect was obtained (Experiment 1). When depth information was in chaos over repeated configurations, visual search was not facilitated and the contextual cueing effect largely crippled (Experiment 2). However, when we made the search items within a tiny random displacement in the 2-dimentional (2D) plane but maintained the depth information constant, the contextual cueing was preserved (Experiment 3). We concluded that the contextual cueing effect was robust in the context provided by 3D space with stereoscopic information, and more importantly, the visual system prioritized stereoscopic information in learning of spatial information when depth information was available.

Reduced Contextual Discrimination following Alcohol Consumption or MDMA Administration in Mice.

PubMed

Johansson, Emily M; García-Gutiérrez, María S; Moscoso-Castro, María; Manzanares, Jorge; Valverde, Olga

2015-01-01

The recreational drugs, alcohol and 3,4-Methylenedioxymethamphetamine (MDMA, "Ecstasy") have both been shown to cause immune activation in vivo, and they are linked to cognitive impairment and anxiety-like behaviors in rodents. The neuronal effects of these drugs in the hippocampal area, an area that has been a focus of studies aiming to explain the mechanisms underlying anxiety related-disorders, remains poorly understood. Therefore we investigated the specific inflammatory impact of alcohol and MDMA on this area of the brain and on a hippocampal-related behavioral task. We centered our study on two inflammatory factors linked to anxiety-related disorders, namely Interleukin-1β (IL-1β) and brain-derived neurotrophic factor (BDNF). We subjected drug-consuming mice to a battery of behavioral tests to evaluate general activity, anxiety-like and depressive-live behaviors. We then introduced them to a contextual fear discrimination task and immune-related effects were examined by immunohistochemical and biochemical studies. Our results suggest that there is a relationship between the induction of immune activated pathways by voluntary alcohol consumption and a high-dose MDMA. Furthermore, the ability of mice to perform a contextual fear discrimination task was impaired by drug consumption and we report long term inflammatory alterations in the hippocampus even several weeks after drug intake. This information will be helpful for discovering new selective drug targets, and to develop treatments and preventive approaches for patients with anxiety-related disorders.

Reduced Contextual Discrimination following Alcohol Consumption or MDMA Administration in Mice

PubMed Central

Johansson, Emily M.; García-Gutiérrez, María S.; Moscoso-Castro, María; Manzanares, Jorge; Valverde, Olga

2015-01-01

The recreational drugs, alcohol and 3,4-Methylenedioxymethamphetamine (MDMA, “Ecstasy”) have both been shown to cause immune activation in vivo, and they are linked to cognitive impairment and anxiety-like behaviors in rodents. The neuronal effects of these drugs in the hippocampal area, an area that has been a focus of studies aiming to explain the mechanisms underlying anxiety related-disorders, remains poorly understood. Therefore we investigated the specific inflammatory impact of alcohol and MDMA on this area of the brain and on a hippocampal-related behavioral task. We centered our study on two inflammatory factors linked to anxiety-related disorders, namely Interleukin-1β (IL-1β) and brain-derived neurotrophic factor (BDNF). We subjected drug-consuming mice to a battery of behavioral tests to evaluate general activity, anxiety-like and depressive-live behaviors. We then introduced them to a contextual fear discrimination task and immune-related effects were examined by immunohistochemical and biochemical studies. Our results suggest that there is a relationship between the induction of immune activated pathways by voluntary alcohol consumption and a high-dose MDMA. Furthermore, the ability of mice to perform a contextual fear discrimination task was impaired by drug consumption and we report long term inflammatory alterations in the hippocampus even several weeks after drug intake. This information will be helpful for discovering new selective drug targets, and to develop treatments and preventive approaches for patients with anxiety-related disorders. PMID:26566284

Impact of explained v. unexplained front-of-package nutrition labels on parent and child food choices: a randomized trial.

PubMed

Graham, Dan J; Lucas-Thompson, Rachel G; Mueller, Megan P; Jaeb, Melanie; Harnack, Lisa

2017-04-01

The present study investigated whether parent/child pairs would select more healthful foods when: (i) products were labelled with front-of-package (FOP) nutrition labels relative to packages without labels; (ii) products were labelled with colour-coded Multiple Traffic Light (MTL) FOP labels relative to monochromatic Facts up Front (FuF) FOP labels; and (iii) FOP labels were explained via in-aisle signage v. unexplained. Participants were randomly assigned to one of five conditions: (i) FuF labels with in-aisle signs explaining the labels; (ii) FuF labels, no signage; (iii) MTL labels with in-aisle signage; (iv) MTL labels, no signage; (v) control group, no labels/signage. Saturated fat, sodium, sugar and energy (calorie) content were compared across conditions. The study took place in a laboratory grocery aisle. Parent/child pairs (n 153) completed the study. Results did not support the hypothesis that MTL labels would lead to more healthful choices than FuF labels. The presence of FOP labels did little to improve the healthfulness of selected foods, with few exceptions (participants with v. without access to FOP labels selected lower-calorie cereals, participants with access to both FOP labels and in-aisle explanatory signage selected products with less saturated fat v. participants without explanatory signage). Neither MTL nor FuF FOP labels led to food choices with significantly lower saturated fat, sodium or sugar. In-aisle signs explaining the FOP labels were somewhat helpful to consumers in making more healthful dietary decisions. New FOP labelling programmes could benefit from campaigns to increase consumer awareness and understanding of the labels.

Promoting Historical Contextualization: The Development and Testing of a Pedagogy

ERIC Educational Resources Information Center

Huijgen, Tim; van de Grift, Wim; van Boxtel, Carla; Holthuis, Paul

2018-01-01

The aim of this explorative study was to develop and test a pedagogy aimed at promoting students' ability to perform historical contextualization. Teaching historical contextualization was conceptualized in terms of four pedagogical design principles: (1) making students aware of the consequences of a present-oriented perspective when examining…

Mice with a fra-1 knock-in into the c-fos locus show impaired spatial but regular contextual learning and normal LTP.

PubMed

Gass, Peter; Fleischmann, Alexander; Hvalby, Oivind; Jensen, Vidar; Zacher, Christiane; Strekalova, Tatyana; Kvello, Ane; Wagner, Erwin F; Sprengel, Rolf

2004-11-04

The immediate early gene c-fos is part of the AP-1 transcription factor complex, which is involved in molecular mechanisms underlying learning and memory. Mice that lack c-Fos in the brain show impairments in spatial reference and contextual learning, and also exhibit a reduced long-term potentiation of synaptic transmission (LTP) at CA3-to-CA1 synapses. In the present study, we investigated mice in which c-fos was deleted and replaced by fra-1 (c-fos(fra-1) mice) to determine whether other members of the c-fos gene family can substitute for the functions of the c-fos gene. In c-fos(fra-1) mice, both CA3-to-CA1 LTP and contextual learning in a Pavlovian fear conditioning task were similar to wild-type littermates, indicating that Fra-1 expression restored the impairments caused by brain-specific c-Fos depletion. However, c-Fos-mediated learning deficits in a reference memory task of the Morris watermaze were also present in c-fos(fra-1) mice. These findings suggest that different c-Fos target genes are involved in LTP, contextual learning, and spatial reference memory formation.

Contextualized science? An Indian experience

NASA Astrophysics Data System (ADS)

Koul, Ravinder

1997-11-01

This study asserts that science is contextualized and should therefore be taught as contextualized. Works of major philosophers in 20th century history, philosophy and sociology of science and recent developments in cognition are discussed in developing a foundation and outlining three themes for contextualized science: (a) science curriculum should emphasize scientific methodology through the generation and testing of knowledge in a specific context, (b) it should validate and evaluate everyday contextual experiences, and (c) develop a context for action by engaging in science, technology and society issues. School science is a major instrument for diffusion and utilization of scientific knowledge. In India, textbooks are often the only classroom source of information for students other than the teacher. The most widely used standard curriculum materials in Indian schools are the National Council of Educational Research and Training (NCERT) textbooks. For schools in the Hoshingabad district of Madhya Pradesh, the state prescribes NCERT materials and materials developed for the Hoshingabad Science Teaching Program (HSTP), a grassroots science education initiative. In this study, the investigation of these curriculum materials and interviews with educators (curriculum developers/textbook authors/teachers at New Delhi and Hoshingabad) are used to establish criteria for both the need and the feasibility of contextualized science. Results of the investigation indicate that the centralized NCERT system of curriculum development has undermined context specific treatment of subject matter in their textbooks. While HSTP attempted to contextualize science in rural schools, the present status of the program may be interpreted as either development and legitimization of another standardized curriculum, or, as the culmination of a gradual erosion and dissipation of conceptually valid and concrete educational practices. There are major situational and institutional constraints

Explaining the 3.5 keV X-ray line in a Lμ‑Lτ extension of the inert doublet model

NASA Astrophysics Data System (ADS)

Biswas, Anirban; Choubey, Sandhya; Covi, Laura; Khan, Sarif

2018-02-01

We explain the existence of neutrino masses and their flavour structure, dark matter relic abundance and the observed 3.5 keV X-ray line within the framework of a gauged U(1)Lμ ‑ Lτ extension of the "scotogenic" model. In the U(1)Lμ ‑ Lτ symmetric limit, two of the RH neutrinos are degenerate in mass, while the third is heavier. The U(1)Lμ ‑ Lτ symmetry is broken spontaneously. Firstly, this breaks the μ‑τ symmetry in the light neutrino sector. Secondly, this results in mild splitting of the two degenerate RH neutrinos, with their mass difference given in terms of the U(1)Lμ ‑ Lτ breaking parameter. Finally, we get a massive Zμτ gauge boson. Due to the added Z2 symmetry under which the RH neutrinos and the inert doublet are odd, the canonical Type-I seesaw is forbidden and the tiny neutrino masses are generated radiatively at one loop. The same Z2 symmetry also ensures that the lightest RH neutrino is stable and the other two can only decay into the lightest one. This makes the two nearly-degenerate lighter neutrinos a two-component dark matter, which in our model are produced by the freeze-in mechanism via the decay of the Zμτ gauge boson in the early universe. We show that the next-to-lightest RH neutrino has a very long lifetime and decays into the lightest one at the present epoch explaining the observed 3.5 keV line.

A Case for Contextual Learning.

ERIC Educational Resources Information Center

Souders, John; Prescott, Carolyn

1999-01-01

Establishing schooling/larger world connections is critical for adolescents. The contextual learning approach views learning as most effective when information is presented within a familiar framework. Employing puzzles, hands-on learning activities, project-based learning, contextual connections, applied math, mentoring, and wider audiences…

Prefrontal neuronal circuits of contextual fear conditioning.

PubMed

Rozeske, R R; Valerio, S; Chaudun, F; Herry, C

2015-01-01

Over the past years, numerous studies have provided a clear understanding of the neuronal circuits and mechanisms involved in the formation, expression and extinction phases of conditioned cued fear memories. Yet, despite a strong clinical interest, a detailed understanding of these memory phases for contextual fear memories is still missing. Besides the well-known role of the hippocampus in encoding contextual fear behavior, growing evidence indicates that specific regions of the medial prefrontal cortex differentially regulate contextual fear acquisition and storage in both animals and humans that ultimately leads to expression of contextual fear memories. In this review, we provide a detailed description of the recent literature on the role of distinct prefrontal subregions in contextual fear behavior and provide a working model of the neuronal circuits involved in the acquisition, expression and generalization of contextual fear memories. © 2014 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

Attention and normalization circuits in macaque V1

PubMed Central

Sanayei, M; Herrero, J L; Distler, C; Thiele, A

2015-01-01

Attention affects neuronal processing and improves behavioural performance. In extrastriate visual cortex these effects have been explained by normalization models, which assume that attention influences the circuit that mediates surround suppression. While normalization models have been able to explain attentional effects, their validity has rarely been tested against alternative models. Here we investigate how attention and surround/mask stimuli affect neuronal firing rates and orientation tuning in macaque V1. Surround/mask stimuli provide an estimate to what extent V1 neurons are affected by normalization, which was compared against effects of spatial top down attention. For some attention/surround effect comparisons, the strength of attentional modulation was correlated with the strength of surround modulation, suggesting that attention and surround/mask stimulation (i.e. normalization) might use a common mechanism. To explore this in detail, we fitted multiplicative and additive models of attention to our data. In one class of models, attention contributed to normalization mechanisms, whereas in a different class of models it did not. Model selection based on Akaike's and on Bayesian information criteria demonstrated that in most cells the effects of attention were best described by models where attention did not contribute to normalization mechanisms. This demonstrates that attentional influences on neuronal responses in primary visual cortex often bypass normalization mechanisms. PMID:25757941

Contextual Effect of Wealth on Independence: An Examination through Regional Differences in China.

PubMed

Takemura, Kosuke; Hamamura, Takeshi; Guan, Yanjun; Suzuki, Satoko

2016-01-01

The current study disentangled two different effects of wealth on psychological tendency toward independence: one is an effect exerted at the individual level (i.e., being rich) and the other one is a contextual effect (i.e., being surrounded by rich individuals). Past research has found a stronger tendency toward independence among people in economically developed societies. This association has often been explained as a result of a greater amount of choices, and thus more opportunities to express individuality that wealth affords individuals. In addition to this individual-level process, theories in cultural psychology imply that the wealth-independence link also reflects social processes-living in a rich society, regardless of one's own wealth, promotes independence (contextual effect of wealth on independence). Through a large-scale survey in China, using multilevel analyses, we found that wealth had both the individual-level effect and contextual effect on independence as well as related psychological tendencies (influence orientation and generalized trust), suggesting that individuals are more likely to be independent with greater personal wealth and when surrounded by wealthy others. Possible processes through which independence is promoted by liing in a wealthy area are discussed.

Contextual Effect of Wealth on Independence: An Examination through Regional Differences in China

PubMed Central

Takemura, Kosuke; Hamamura, Takeshi; Guan, Yanjun; Suzuki, Satoko

2016-01-01

The current study disentangled two different effects of wealth on psychological tendency toward independence: one is an effect exerted at the individual level (i.e., being rich) and the other one is a contextual effect (i.e., being surrounded by rich individuals). Past research has found a stronger tendency toward independence among people in economically developed societies. This association has often been explained as a result of a greater amount of choices, and thus more opportunities to express individuality that wealth affords individuals. In addition to this individual-level process, theories in cultural psychology imply that the wealth-independence link also reflects social processes—living in a rich society, regardless of one’s own wealth, promotes independence (contextual effect of wealth on independence). Through a large-scale survey in China, using multilevel analyses, we found that wealth had both the individual-level effect and contextual effect on independence as well as related psychological tendencies (influence orientation and generalized trust), suggesting that individuals are more likely to be independent with greater personal wealth and when surrounded by wealthy others. Possible processes through which independence is promoted by liing in a wealthy area are discussed. PMID:27014175

Culture and personality disorder: from a fragmented literature to a contextually grounded alternative.

PubMed

Ryder, Andrew G; Sunohara, Momoka; Kirmayer, Laurence J

2015-01-01

The aim of this review is twofold: to review recent literature on personality disorders, published in 2013 and the first half of 2014; and to use recent theoretical work to argue for a contextually grounded approach to culture and personality disorder. Recent large-sample studies suggest that U.S. ethnoracial groups differ in personality disorder diagnostic rates, but also that minority groups are less likely to receive treatment for personality disorder. Most of these studies do not test explanations for these differences. However, two studies demonstrate that socioeconomic status partly explains group differences between African-Americans and European Americans. Several new studies test the psychometric properties of instruments relevant to personality disorder research in various non-Western samples. Ongoing theoretical work advocates much more attention to cultural context. Recent investigations of hikikomori, a Japanese social isolation syndrome with similarities to some aspects of personality disorder, are used to demonstrate approaches to contextually grounded personality disorder research. Studies of personality disorder must understand patients in sociocultural context considering the dynamic interactions between personality traits, developmental histories of adversity and current social context. Research examining these interactions can guide contextually grounded clinical work with patients with personality disorder.

Influence of organic ions on DNA damage induced by 1 eV to 60 keV electrons.

PubMed

Zheng, Yi; Sanche, Léon

2010-10-21

We report the results of a study on the influence of organic salts on the induction of single strand breaks (SSBs) and double strand breaks (DSBs) in DNA by electrons of 1 eV to 60 keV. Plasmid DNA films are prepared with two different concentrations of organic salts, by varying the amount of the TE buffer (Tris-HCl and EDTA) in the films with ratio of 1:1 and 6:1 Tris ions to DNA nucleotide. The films are bombarded with electrons of 1, 10, 100, and 60 000 eV under vacuum. The damage to the 3197 base-pair plasmid is analyzed ex vacuo by agarose gel electrophoresis. The highest yields are reached at 100 eV and the lowest ones at 60 keV. The ratios of SSB to DSB are surprisingly low at 10 eV (∼4.3) at both salt concentrations, and comparable to the ratios measured with 100 eV electrons. At all characteristic electron energies, the yields of SSB and DSB are found to be higher for the DNA having the lowest salt concentration. However, the organic salts are more efficient at protecting DNA against the damage induced by 1 and 10 eV electrons. DNA damage and protection by organic ions are discussed in terms of mechanisms operative at each electron energy. It is suggested that these ions create additional electric fields within the groove of DNA, which modify the resonance parameter of 1 and 10 eV electrons, namely, by reducing the electron capture cross-section of basic DNA units and the lifetime of corresponding transient anions. An interstrand electron transfer mechanism is proposed to explain the low ratios for the yields of SSB to those of DSB produced by 10 eV electrons.

Influence of organic ions on DNA damage induced by 1 eV to 60 keV electrons

PubMed Central

Zheng, Yi; Sanche, Léon

2011-01-01

We report the results of a study on the influence of organic salts on the induction of single strand breaks (SSBs) and double strand breaks (DSBs) in DNA by electrons of 1 eV to 60 keV. Plasmid DNA films are prepared with two different concentrations of organic salts, by varying the amount of the TE buffer (Tris-HCl and EDTA) in the films with ratio of 1:1 and 6:1 Tris ions to DNA nucleotide. The films are bombarded with electrons of 1, 10, 100, and 60 000 eV under vacuum. The damage to the 3197 base-pair plasmid is analyzed ex vacuo by agarose gel electrophoresis. The highest yields are reached at 100 eV and the lowest ones at 60 keV. The ratios of SSB to DSB are surprisingly low at 10 eV (~4.3) at both salt concentrations, and comparable to the ratios measured with 100 eV electrons. At all characteristic electron energies, the yields of SSB and DSB are found to be higher for the DNA having the lowest salt concentration. However, the organic salts are more efficient at protecting DNA against the damage induced by 1 and 10 eV electrons. DNA damage and protection by organic ions are discussed in terms of mechanisms operative at each electron energy. It is suggested that these ions create additional electric fields within the groove of DNA, which modify the resonance parameter of 1 and 10 eV electrons, namely, by reducing the electron capture cross-section of basic DNA units and the lifetime of corresponding transient anions. An interstrand electron transfer mechanism is proposed to explain the low ratios for the yields of SSB to those of DSB produced by 10 eV electrons. PMID:20969428

Attentional and Contextual Priors in Sound Perception.

PubMed

Wolmetz, Michael; Elhilali, Mounya

2016-01-01

Behavioral and neural studies of selective attention have consistently demonstrated that explicit attentional cues to particular perceptual features profoundly alter perception and performance. The statistics of the sensory environment can also provide cues about what perceptual features to expect, but the extent to which these more implicit contextual cues impact perception and performance, as well as their relationship to explicit attentional cues, is not well understood. In this study, the explicit cues, or attentional prior probabilities, and the implicit cues, or contextual prior probabilities, associated with different acoustic frequencies in a detection task were simultaneously manipulated. Both attentional and contextual priors had similarly large but independent impacts on sound detectability, with evidence that listeners tracked and used contextual priors for a variety of sound classes (pure tones, harmonic complexes, and vowels). Further analyses showed that listeners updated their contextual priors rapidly and optimally, given the changing acoustic frequency statistics inherent in the paradigm. A Bayesian Observer model accounted for both attentional and contextual adaptations found with listeners. These results bolster the interpretation of perception as Bayesian inference, and suggest that some effects attributed to selective attention may be a special case of contextual prior integration along a feature axis.

28Silicon Irradiation Impairs Contextual Fear Memory in B6D2F1 Mice.

PubMed

Raber, Jacob; Marzulla, Tessa; Stewart, Blair; Kronenberg, Amy; Turker, Mitchell S

2015-06-01

The space radiation environment consists of multiple species of charged particles, including (28)Si, (48)Ti and protons that may impact cognition, but their damaging effects have been poorly defined. In mouse studies, C57Bl6/J homozygous wild-type mice and genetic mutant mice on a C57Bl6/J background have typically been used for assessing effects of space radiation on cognition. In contrast, little is known about the radiation response of mice on a heterozygous background. Therefore, in the current study we tested the effects of (28)Si, (48)Ti and proton radiation on hippocampus-dependent contextual fear memory and hippocampus-independent cued fear memory in C57Bl6/J × DBA2/J F1 (B6D2F1) mice three months after irradiation. Contextual fear memory was impaired at a 1.6 Gy dose of (28)Si radiation, but not cued fear memory. (48)Ti or proton irradiation did not affect either type of memory. Based on earlier space radiation cognitive data in C57Bl6/J mice, these data highlight the importance of including different genetic backgrounds in studies aimed at assessing cognitive changes after exposure to space radiation.

Explaining the R_K and R_{K^*} anomalies

NASA Astrophysics Data System (ADS)

Ghosh, Diptimoy

2017-10-01

Recent LHCb results on R_{K^*}, the ratio of the branching fractions of B → K^* μ ^+ μ ^- to that of B → K^* e^+ e^-, for the dilepton invariant mass bins q^2 ≡ m_{ℓ ℓ }^2 = [0.045-1.1] GeV^2 and [1.1-6] GeV^2 show approximately 2.5 σ deviations from the corresponding Standard Model prediction in each of the bins. This, when combined with the measurement of R_K (q^2=[1-6] GeV^2), a similar ratio for the decay to a pseudo-scalar meson, highly suggests lepton non-universal new physics in semi-leptonic B meson decays. In this work, we perform a model independent analysis of these potential new physics signals and identify the operators that do the best job in satisfying all these measurements. We show that heavy new physics, giving rise to q^2 independent local 4-Fermi operators of scalar, pseudo-scalar, vector or axial-vector type, is unable to explain all the three measurements simultaneously, in particular R_{K^*} in the bin [0.045-1.1], within their experimental 1σ regions. We point out the possibility to explain R_{K^*} in the low bin by an additional light (≲ 20 {MeV}) vector boson with appropriate coupling strengths to (\\bar{b} s) and (\\bar{e} e).

Contextual determinants of neonatal mortality using two analysis methods, Rio Grande do Sul, Brazil.

PubMed

Zanini, Roselaine Ruviaro; Moraes, Anaelena Bragança de; Giugliani, Elsa Regina Justo; Riboldi, João

2011-02-01

To analyze neonatal mortality determinants using multilevel logistic regression and classic hierarchical models. Cohort study including 138,407 live births with birth certificates and 1,134 neonatal deaths recorded in 2003, in the state of Rio Grande do Sul, Southern Brazil. The Information System on Live Births and mortality records were linked for gathering information on individual-level exposures. Sociodemographic data and information on the pregnancy, childbirth care and characteristics of the children at birth were collected. The associated factors were estimated and compared by traditional and multilevel logistic regression analysis. The neonatal mortality rate was 8.19 deaths per 1,000 live births. Low birth weight, 1- and 5-minute Apgar score below eight, congenital malformation, pre-term birth and previous fetal loss were associated with neonatal death in the traditional model. Elective cesarean section had a protective effect. Previous fetal loss did not remain significant in the multilevel model, but the inclusion of a contextual variable (poverty rate) showed that 15% of neonatal mortality variation can be explained by varying poverty rates in the microregions. The use of multilevel models showed a small effect of contextual determinants on the neonatal mortality rate. There was found a positive association with the poverty rate in the general model, and the proportion of households with water supply among preterm newborns.

Attentional and Contextual Priors in Sound Perception

PubMed Central

Wolmetz, Michael; Elhilali, Mounya

2016-01-01

Behavioral and neural studies of selective attention have consistently demonstrated that explicit attentional cues to particular perceptual features profoundly alter perception and performance. The statistics of the sensory environment can also provide cues about what perceptual features to expect, but the extent to which these more implicit contextual cues impact perception and performance, as well as their relationship to explicit attentional cues, is not well understood. In this study, the explicit cues, or attentional prior probabilities, and the implicit cues, or contextual prior probabilities, associated with different acoustic frequencies in a detection task were simultaneously manipulated. Both attentional and contextual priors had similarly large but independent impacts on sound detectability, with evidence that listeners tracked and used contextual priors for a variety of sound classes (pure tones, harmonic complexes, and vowels). Further analyses showed that listeners updated their contextual priors rapidly and optimally, given the changing acoustic frequency statistics inherent in the paradigm. A Bayesian Observer model accounted for both attentional and contextual adaptations found with listeners. These results bolster the interpretation of perception as Bayesian inference, and suggest that some effects attributed to selective attention may be a special case of contextual prior integration along a feature axis. PMID:26882228

Measuring Contextual Characteristics for Community Health

PubMed Central

Hillemeier, Marianne M; Lynch, John; Harper, Sam; Casper, Michele

2003-01-01

Objective To conceptualize and measure community contextual influences on population health and health disparities. Data Sources We use traditional and nontraditional secondary sources of data comprising a comprehensive array of community characteristics. Study Design Using a consultative process, we identify 12 overarching dimensions of contextual characteristics that may affect community health, as well as specific subcomponents relating to each dimension. Data Collection An extensive geocoded library of data indicators relating to each dimension and subcomponent for metropolitan areas in the United States is assembled. Principal Findings We describe the development of community contextual health profiles, present the rationale supporting each of the profile dimensions, and provide examples of relevant data sources. Conclusions Our conceptual framework for community contextual characteristics, including a specified set of dimensions and components, can provide practical ways to monitor health-related aspects of the economic, social, and physical environments in which people live. We suggest several guiding principles useful for understanding how aspects of contextual characteristics can affect health and health disparities. PMID:14727793

Selective neuronal degeneration in the retrosplenial cortex impairs the recall of contextual fear memory.

PubMed

Sigwald, Eric L; Genoud, Manuel E; Giachero, Marcelo; de Olmos, Soledad; Molina, Víctor A; Lorenzo, Alfredo

2016-05-01

The retrosplenial cortex (RSC) is one of the largest cortical areas in rodents, and is subdivided in two main regions, A29 and A30, according to their cytoarchitectural organization and connectivities. However, very little is known about the functional activity of each RSC subdivision during the execution of complex cognitive tasks. Here, we used a well-established fear learning protocol that induced long-lasting contextual fear memory and showed that during evocation of the fear memory, the expression of early growth response gene 1 was up-regulated in A30, and in other brain areas implicated in fear and spatial memory, however, was down-regulated in A29, including layers IV and V. To search for the participation of A29 on fear memory, we triggered selective degeneration of neurons within cortical layers IV and V of A29 by using a non-invasive protocol that takes advantage of the vulnerability that these neurons have MK801-toxicity and the modulation of this neurodegeneration by testosterone. Application of 5 mg/kg MK801 in intact males induced negligible neuronal degeneration of A29 neurons and had no impact on fear memory retrieval. However, in orchiectomized rats, 5 mg/kg MK801 induced overt degeneration of layers IV-V neurons of A29, significantly impairing fear memory recall. Degeneration of A29 neurons did not affect exploratory or anxiety-related behavior nor altered unconditioned freezing. Importantly, protecting A29 neurons from MK801-toxicity by testosterone preserved fear memory recall in orchiectomized rats. Thus, neurons within cortical layers IV-V of A29 are critically required for efficient retrieval of contextual fear memory.

SPERT1. Contextual aerial view of SPERTI Reactor Pit Building (PER605) ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

SPERT-1. Contextual aerial view of SPERT-I Reactor Pit Building (PER-605) at top of view, and its accessories: the earth-shielded instrument cell (PER-606) immediately adjacent to it; the Guard House (PER-607) to its right; and the Terminal Building in lower center of view (PER-604). Camera faces west. Road and buried line leaving view at right lead to Control Building (PER-601) out of view. Sagebrush vegetation has been scraped from around buildings. Photographer: R.G. Larsen. Date: June 6, 1955. INEEL negative no. 55-1477. - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

Quantifying Contextual Interference and Its Effect on Skill Transfer in Skilled Youth Tennis Players

PubMed Central

Buszard, Tim; Reid, Machar; Krause, Lyndon; Kovalchik, Stephanie; Farrow, Damian

2017-01-01

The contextual interference effect is a well-established motor learning phenomenon. Most of the contextual interference effect literature has addressed simple skills, while less is known about the role of contextual interference in complex sport skill practice, particularly with respect to skilled performers. The purpose of this study was to assess contextual interference when practicing the tennis serve. Study 1 evaluated tennis serve practice of nine skilled youth tennis players using a novel statistical metric developed specifically to measure between-skill and within-skill variability as sources of contextual interference. This metric highlighted that skilled tennis players typically engaged in serve practice that featured low contextual interference. In Study 2, 16 skilled youth tennis players participated in 10 practice sessions that aimed to improve serving “down the T.” Participants were stratified into a low contextual interference practice group (Low CI) and a moderate contextual interference practice group (Moderate CI). Pre- and post-tests were conducted 1 week before and 1 week after the practice period. Testing involved a skill test, which assessed serving performance in a closed setting, and a transfer test, which assessed serving performance in a match-play setting. No significant contextual interference differences were observed with respect to practice performance. However, analysis of pre- and post-test serve performance revealed significant Group × Time interactions. The Moderate CI group showed no change in serving performance (service displacement from the T) from pre- to post-test in the skill test, but did display improvements in the transfer test. Conversely, the Low CI group improved serving performance (service displacement from the T) in the skill test but not the transfer test. Results suggest that the typical contextual interference effect is less clear when practicing a complex motor skill, at least with the tennis serve skill

Contextually Mediated Spontaneous Retrieval Is Specific to the Hippocampus

PubMed Central

Long, Nicole M.; Sperling, Michael R.; Worrell, Gregory A.; Davis, Kathryn A.; Gross, Robert E.; Lega, Bradley C.; Jobst, Barbara C.; Sheth, Sameer A.; Zaghloul, Kareem; Stein, Joel M.; Kahana, Michael J.

2018-01-01

SUMMARY Although it is now well established that the hippocampus supports memory encoding [1, 2], little is known about hippocampal activity during spontaneous memory retrieval. Recent intracranial electroencephalographic (iEEG) work has shown that hippocampal activity during encoding predicts subsequent temporal organization of memories [3], supporting a role in contextual binding. It is an open question, however, whether the hippocampus similarly supports contextually mediated processes during retrieval. Here, we analyzed iEEG recordings obtained from 215 epilepsy patients as they performed a free recall task. To identify neural activity specifically associated with contextual retrieval, we compared correct recalls, intrusions (incorrect recall of either items from prior lists or items not previously studied), and deliberations (matched periods during recall when no items came to mind). Neural signals that differentiate correct recalls from both other retrieval classes reflect contextual retrieval, as correct recalls alone arise from the correct context. We found that in the hippocampus, high-frequency activity (HFA, 44–100 Hz), a proxy for neural activation [4], was greater prior to correct recalls relative to the other retrieval classes, with no differentiation between intrusions and deliberations. This pattern was not observed in other memory-related cortical regions, including DLPFC, thus supporting a specific hippocampal contribution to contextually mediated memory retrieval. PMID:28343962

Facilitating Student Learning through Contextualization: A Review of Evidence

ERIC Educational Resources Information Center

Perin, Dolores

2011-01-01

This is a review of evidence for contextualization, defined here as an instructional approach connecting foundational skills and college-level content. Two forms of contextualization are identified, "contextualized" and "integrated" instruction. Despite methodological limitations, the available studies suggest that contextualization has the…

Attention and normalization circuits in macaque V1.

PubMed

Sanayei, M; Herrero, J L; Distler, C; Thiele, A

2015-04-01

Attention affects neuronal processing and improves behavioural performance. In extrastriate visual cortex these effects have been explained by normalization models, which assume that attention influences the circuit that mediates surround suppression. While normalization models have been able to explain attentional effects, their validity has rarely been tested against alternative models. Here we investigate how attention and surround/mask stimuli affect neuronal firing rates and orientation tuning in macaque V1. Surround/mask stimuli provide an estimate to what extent V1 neurons are affected by normalization, which was compared against effects of spatial top down attention. For some attention/surround effect comparisons, the strength of attentional modulation was correlated with the strength of surround modulation, suggesting that attention and surround/mask stimulation (i.e. normalization) might use a common mechanism. To explore this in detail, we fitted multiplicative and additive models of attention to our data. In one class of models, attention contributed to normalization mechanisms, whereas in a different class of models it did not. Model selection based on Akaike's and on Bayesian information criteria demonstrated that in most cells the effects of attention were best described by models where attention did not contribute to normalization mechanisms. This demonstrates that attentional influences on neuronal responses in primary visual cortex often bypass normalization mechanisms. © 2015 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

The impact of contextualization on immersion in healthcare simulation.

PubMed

Engström, Henrik; Andersson Hagiwara, Magnus; Backlund, Per; Lebram, Mikael; Lundberg, Lars; Johannesson, Mikael; Sterner, Anders; Maurin Söderholm, Hanna

2016-01-01

The aim of this paper is to explore how contextualization of a healthcare simulation scenarios impacts immersion, by using a novel objective instrument, the Immersion Score Rating Instrument. This instrument consists of 10 triggers that indicate reduced or enhanced immersion among participants in a simulation scenario. Triggers refer to events such as jumps in time or space (sign of reduced immersion) and natural interaction with the manikin (sign of enhanced immersion) and can be used to calculate an immersion score. An experiment using a randomized controlled crossover design was conducted to compare immersion between two simulation training conditions for prehospital care: one basic and one contextualized. The Immersion Score Rating Instrument was used to compare the total immersion score for the whole scenario, the immersion score for individual mission phases, and to analyze differences in trigger occurrences. A paired t test was used to test for significance. The comparison shows that the overall immersion score for the simulation was higher in the contextualized condition. The average immersion score was 2.17 (sd = 1.67) in the contextualized condition and -0.77 (sd = 2.01) in the basic condition ( p  < .001). The immersion score was significantly higher in the contextualized condition in five out of six mission phases. Events that might be disruptive for the simulation participants' immersion, such as interventions of the instructor and illogical jumps in time or space, are present to a higher degree in the basic scenario condition; while events that signal enhanced immersion, such as natural interaction with the manikin, are more frequently observed in the contextualized condition. The results suggest that contextualization of simulation training with respect to increased equipment and environmental fidelity as well as functional task alignment might affect immersion positively and thus contribute to an improved training experience.

Contextual factors and clinical reasoning: differences in diagnostic and therapeutic reasoning in board certified versus resident physicians.

PubMed

McBee, Elexis; Ratcliffe, Temple; Picho, Katherine; Schuwirth, Lambert; Artino, Anthony R; Yepes-Rios, Ana Monica; Masel, Jennifer; van der Vleuten, Cees; Durning, Steven J

2017-11-15

The impact of context on the complex process of clinical reasoning is not well understood. Using situated cognition as the theoretical framework and videos to provide the same contextual "stimulus" to all participants, we examined the relationship between specific contextual factors on diagnostic and therapeutic reasoning accuracy in board certified internists versus resident physicians. Each participant viewed three videotaped clinical encounters portraying common diagnoses in internal medicine. We explicitly modified the context to assess its impact on performance (patient and physician contextual factors). Patient contextual factors, including English as a second language and emotional volatility, were portrayed in the videos. Physician participant contextual factors were self-rated sleepiness and burnout.. The accuracy of diagnostic and therapeutic reasoning was compared with covariates using Fisher Exact, Mann-Whitney U tests and Spearman Rho's correlations as appropriate. Fifteen board certified internists and 10 resident physicians participated from 2013 to 2014. Accuracy of diagnostic and therapeutic reasoning did not differ between groups despite residents reporting significantly higher rates of sleepiness (mean rank 20.45 vs 8.03, U = 0.5, p < .001) and burnout (mean rank 20.50 vs 8.00, U = 0.0, p < .001). Accuracy of diagnosis and treatment were uncorrelated (r = 0.17, p = .65). In both groups, the proportion scoring correct responses for treatment was higher than the proportion scoring correct responses for diagnosis. This study underscores that specific contextual factors appear to impact clinical reasoning performance. Further, the processes of diagnostic and therapeutic reasoning, although related, may not be interchangeable. This raises important questions about the impact that contextual factors have on clinical reasoning and provides insight into how clinical reasoning processes in more authentic settings may be explained by situated

Contextual cueing improves attentional guidance, even when guidance is supposedly optimal.

PubMed

Harris, Anthony M; Remington, Roger W

2017-05-01

Visual search through previously encountered contexts typically produces reduced reaction times compared with search through novel contexts. This contextual cueing benefit is well established, but there is debate regarding its underlying mechanisms. Eye-tracking studies have consistently shown reduced number of fixations with repetition, supporting improvements in attentional guidance as the source of contextual cueing. However, contextual cueing benefits have been shown in conditions in which attentional guidance should already be optimal-namely, when attention is captured to the target location by an abrupt onset, or under pop-out conditions. These results have been used to argue for a response-related account of contextual cueing. Here, we combine eye tracking with response time to examine the mechanisms behind contextual cueing in spatially cued and pop-out conditions. Three experiments find consistent response time benefits with repetition, which appear to be driven almost entirely by a reduction in number of fixations, supporting improved attentional guidance as the mechanism behind contextual cueing. No differences were observed in the time between fixating the target and responding-our proxy for response related processes. Furthermore, the correlation between contextual cueing magnitude and the reduction in number of fixations on repeated contexts approaches 1. These results argue strongly that attentional guidance is facilitated by familiar search contexts, even when guidance is near-optimal. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

A Pilot Study of a Functional Contextual Treatment for Bulimia Nervosa

ERIC Educational Resources Information Center

Anderson, Drew A.; Simmons, Angela M.

2008-01-01

This paper describes the initial development of a treatment for bulimia nervosa using a functional contextual treatment approach. Seven women (6 with a diagnosis of bulimia nervosa and 1 with a diagnosis of eating disorder not otherwise specified) completed 12 sessions of functional contextual treatment. Participants were assessed with the Eating…

Survey of NASA V and V Processes/Methods

NASA Technical Reports Server (NTRS)

Pecheur, Charles; Nelson, Stacy

2002-01-01

The purpose of this report is to describe current NASA Verification and Validation (V&V) techniques and to explain how these techniques are applicable to 2nd Generation RLV Integrated Vehicle Health Management (IVHM) software. It also contains recommendations for special V&V requirements for IVHM. This report is divided into the following three sections: 1) Survey - Current NASA V&V Processes/Methods; 2) Applicability of NASA V&V to 2nd Generation RLV IVHM; and 3) Special 2nd Generation RLV IVHM V&V Requirements.

Properties of Contextual Memory Formed in the Absence of αCaMKII Autophosphorylation

PubMed Central

2011-01-01

The alpha-isoform of calcium/calmodulin-dependent kinase II (αCaMKII) is a major synaptic kinase that undergoes autophosphorylation after NMDA receptor activation, switching the kinase into a calcium-independent activity state. This αCaMKII autophosphorylation is essential for NMDA receptor-dependent long-term potentiation (LTP), induced by a single tetanus, in hippocampal area CA1 and in neocortex. Furthermore, the αCaMKII autophosphorylation is essential for contextual long-term memory (LTM) formation after a single training trial but not after a massed training session. Here, we show that in the absence of αCaMKII autophosphorylation contextual fear conditioning is hippocampus dependent and that multi-tetanus-dependent late-LTP cannot be induced in hippocampal area CA1. Furthermore, we show that in the absence of αCaMKII autophosphorylation contextual LTM persists for 30 days, the latest time point tested. Additionally, contextual, but not cued, LTM formation in the absence of αCaMKII autophosphorylation appears to be impaired in 18 month-old mice. Taken together, our findings suggest that αCaMKII autophosphorylation-independent plasticity in the hippocampus is sufficient for contextual LTM formation and that αCaMKII autophosphorylation may be important for delaying age-related impairments in hippocampal memory formation. Furthermore, they propose that NMDA receptor-dependent LTP in hippocampal area CA1 is essential for contextual LTM formation after a single trial but not after massed training. Finally, our results challenge the proposal that NMDA receptor-dependent LTP in neocortex is required for remote contextual LTM. PMID:21276220

Acute stress blocks the caffeine-induced enhancement of contextual memory retrieval in mice.

PubMed

Pierard, Chistophe; Krazem, Ali; Henkous, Nadia; Decorte, Laurence; Béracochéa, Daniel

2015-08-15

This study investigated in mice the dose-effect of caffeine on memory retrieval in non-stress and stress conditions. C57 Bl/6 Jico mice learned two consecutive discriminations (D1 and D2) in a four-hole board which involved either distinct contextual (CSD) or similar contextual (SSD) cues. All mice received an i.p. injection of vehicle or caffeine (8, 16 or 32mg/kg) 30min before the test session. Results showed that in non-stress conditions, the 16mg/kg caffeine dose induced a significant enhancement of D1 performance in CSD but not in SSD. Hence, we studied the effect of an acute stress (electric footshocks) administered 15min before the test session on D1 performance in caffeine-treated mice. Results showed that stress significantly decreased D1 performance in vehicle-treated controls and the memory-enhancing effect induced by the 16mg/kg caffeine dose in non-stress condition is no longer observed. Interestingly, whereas caffeine-treated mice exhibited weaker concentrations of plasma corticosterone as compared to vehicles in non-stress condition, stress significantly increased plasma corticosterone concentrations in caffeine-treated mice which reached similar level to that of controls. Overall, the acute stress blocked both the endocrinological and memory retrieval enhancing effects of caffeine. Copyright © 2015 Elsevier B.V. All rights reserved.

Electrolytic lesions of the bilateral ventrolateral orbital cortex inhibit methamphetamine-associated contextual memory formation in rats.

PubMed

Zhao, Yan; Liu, Peng; Chu, Zheng; Liu, Fei; Han, Wei; Xun, Xi; Dang, Yong-Hui

2015-10-22

The memories that are formed between rewarding and drug-associated contextual cues have been suggested to contribute to drug addiction relapse. Recent evidence has indicated that the ventrolateral orbital cortex (VLO) plays important roles in reward-based learning and reversal learning. However, whether the VLO is required for methamphetamine-induced contextual memory formation is not well understood. In the present study, a three-phase methamphetamine-induced conditioned place preference (CPP) model was used to investigate the effects of VLO lesions on the formation of drug-associated contextual memories in rats. We found that the VLO lesions themselves elicited no observable effects on place preferences. However, the VLO lesions delayed the acquisition and extinction phases of CPP without affecting the expression level. Furthermore, the VLO lesions did not have an obvious influence on CPP reinstatement. These results indicate that electrolytic lesions of the bilateral ventrolateral orbital cortex can inhibit the formation of methamphetamine-induced contextual memories in rats. Moreover, VLO may not be critically involved in memory storage and retrieval. Copyright © 2015 Elsevier B.V. All rights reserved.

Unilateral hippocampal inactivation or lesion selectively impairs remote contextual fear memory.

PubMed

Zhou, Heng; Zhou, Qixin; Xu, Lin

2016-10-01

Contextual fear memory depends on the hippocampus, but the role of unilateral hippocampus in this type of memory remains unclear. Herein, pharmacological inactivation or excitotoxic lesions were used to study the role of unilateral hippocampus in the stages of contextual fear memory. The pharmacological experiments revealed that compared with the control groups, unilateral hippocampal blockade did not impair 1-day recent memory following learning, whereas bilateral hippocampal blockade significantly impaired this memory. The lesion experiments showed that compared with the control groups, the formed contextual fear memory was retained for 7 days and that 30-day remote memory was markedly reduced in unilateral hippocampal lesion groups. These results indicate that an intact bilateral hippocampus is required for the formation of remote memory and that unilateral hippocampus is sufficient for recent contextual fear memory.

Is there contextuality in behavioural and social systems?

PubMed

Dzhafarov, E N; Zhang, Ru; Kujala, Janne

2016-01-13

Most behavioural and social experiments aimed at revealing contextuality are confined to cyclic systems with binary outcomes. In quantum physics, this broad class of systems includes as special cases Klyachko-Can-Binicioglu-Shumovsky-type, Einstein-Podolsky-Rosen-Bell-type and Suppes-Zanotti-Leggett-Garg-type systems. The theory of contextuality known as contextuality-by-default allows one to define and measure contextuality in all such systems, even if there are context-dependent errors in measurements, or if something in the contexts directly interacts with the measurements. This makes the theory especially suitable for behavioural and social systems, where direct interactions of 'everything with everything' are ubiquitous. For cyclic systems with binary outcomes, the theory provides necessary and sufficient conditions for non-contextuality, and these conditions are known to be breached in certain quantum systems. We review several behavioural and social datasets (from polls of public opinion to visual illusions to conjoint choices to word combinations to psychophysical matching), and none of these data provides any evidence for contextuality. Our working hypothesis is that this may be a broadly applicable rule: behavioural and social systems are non-contextual, i.e. all 'contextual effects' in them result from the ubiquitous dependence of response distributions on the elements of contexts other than the ones to which the response is presumably or normatively directed. © 2015 The Author(s).

Chronic nicotine differentially alters spontaneous recovery of contextual fear in male and female mice.

PubMed

Tumolo, Jessica M; Kutlu, Munir Gunes; Gould, Thomas J

2018-04-02

Post-traumatic stress disorder (PTSD) is a devastating disorder with symptoms such as flashbacks, hyperarousal, and avoidance of reminders of the traumatic event. Exposure therapy, which attempts to extinguish fear responses, is a commonly used treatment for PTSD but relapse following successful exposure therapy is a frequent problem. In rodents, spontaneous recovery (SR), where extinguished fear responses resurface following extinction treatment, is used as a model of fear relapse. Previous studies from our lab showed that chronic nicotine impaired fear extinction and acute nicotine enhanced SR of contextual fear in adult male mice. In addition, we showed that acute nicotine's effects were specific to SR as acute nicotine did not affect recall of contextual fear conditioning in the absence of extinction. However, effects of chronic nicotine administration on SR are not known. Therefore, in the present study, we investigated if chronic nicotine administration altered SR or recall of contextual fear in adult male and female C57BL/6J mice. Our results showed that chronic nicotine significantly enhanced SR in female mice and significantly decreased SR in males. Chronic nicotine had no effect on recall of contextual fear in males or females. Female sham mice also had significantly less baseline SR than male sham mice. Overall, these results demonstrate sex differences in SR of fear memories and that chronic nicotine modulates these effects on SR but nicotine does not alter recall of contextual fear. Copyright © 2018 Elsevier B.V. All rights reserved.

Long-term contextual memory in infant rats as evidenced by an ethanol conditioned tolerance procedure.

PubMed

Castelló, Stefanía; Molina, Juan Carlos; Arias, Carlos

2017-08-14

Conditioned tolerance can be conceptualized as a particular case of Pavlovian conditioning in which contextual cues play the role of the conditioned stimulus. Although the evidence is contradictory, it is frequently assumed that long-term contextual conditioning in pre-weanling rats is weak or even absent. This hypothesis comes from and is sustained mainly by behavioral studies that explored different contextual effects in 16-18day-old rats using a fear-conditioning paradigm, but their conclusions are stated in terms of an immature (hippocampal-dependent) declarative memory system. The main goal of the present manuscript was based on a recent antecedent from our laboratory, to analyze whether context-dependent tolerance induced by ethanol during the pre-weanling period persists over time. Results showed that the context was able to modulate ethanol-induced tolerance in 2- and 3-week-old rats. Interestingly, contextual conditioned tolerance was stronger (in terms of persistence) during the third than during the second postnatal week. When subjects were tested 8days after training, when the context presumably lost its influence over tolerance, the opposite effect emerged (sensitization). These results are important for the ethanol literature, adding new evidence of long-term retention of ethanol effects acquired during infancy, whilst also showing striking ontogenetic differences in the sensitivity to ethanol between the 2nd and 3rd postnatal weeks. Importantly, contextual information modulates the expression of these ethanol effects even eight days after training, a result that is particularly relevant to the discussion of the ontogeny of contextual memory. Copyright © 2017 Elsevier B.V. All rights reserved.

Contextual fear conditioning in zebrafish.

PubMed

Kenney, Justin W; Scott, Ian C; Josselyn, Sheena A; Frankland, Paul W

2017-10-01

Zebrafish are a genetically tractable vertebrate that hold considerable promise for elucidating the molecular basis of behavior. Although numerous recent advances have been made in the ability to precisely manipulate the zebrafish genome, much less is known about many aspects of learning and memory in adult fish. Here, we describe the development of a contextual fear conditioning paradigm using an electric shock as the aversive stimulus. We find that contextual fear conditioning is modulated by shock intensity, prevented by an established amnestic agent (MK-801), lasts at least 14 d, and exhibits extinction. Furthermore, fish of various background strains (AB, Tu, and TL) are able to acquire fear conditioning, but differ in fear extinction rates. Taken together, we find that contextual fear conditioning in zebrafish shares many similarities with the widely used contextual fear conditioning paradigm in rodents. Combined with the amenability of genetic manipulation in zebrafish, we anticipate that our paradigm will prove to be a useful complementary system in which to examine the molecular basis of vertebrate learning and memory. © 2017 Kenney et al.; Published by Cold Spring Harbor Laboratory Press.

Contextual information and perceptual-cognitive expertise in a dynamic, temporally-constrained task.

PubMed

Murphy, Colm P; Jackson, Robin C; Cooke, Karl; Roca, André; Benguigui, Nicolas; Williams, A Mark

2016-12-01

Skilled performers extract and process postural information from an opponent during anticipation more effectively than their less-skilled counterparts. In contrast, the role and importance of contextual information in anticipation has received only minimal attention. We evaluate the importance of contextual information in anticipation and examine the underlying perceptual-cognitive processes. We present skilled and less-skilled tennis players with normal video or animated footage of the same rallies. In the animated condition, sequences were created using player movement and ball trajectory data, and postural information from the players was removed, constraining participants to anticipate based on contextual information alone. Participants judged ball bounce location of the opponent's final occluded shot. The 2 groups were more accurate than chance in both display conditions with skilled being more accurate than less-skilled (Exp. 1) participants. When anticipating based on contextual information alone, skilled participants employed different gaze behaviors to less-skilled counterparts and provided verbal reports of thoughts which were indicative of more thorough evaluation of contextual information (Exp. 2). Findings highlight the importance of both postural and contextual information in anticipation and indicate that perceptual-cognitive expertise is underpinned by processes that facilitate more effective processing of contextual information, in the absence of postural information. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

The Missing Link: Deficits of Country-Level Studies. A Review of 22 Articles Explaining Life Satisfaction

ERIC Educational Resources Information Center

Nonnenmacher, Alexandra; Friedrichs, Jurgen

2013-01-01

To explain country differences in an analytical or structural dependent variable, the application of a macro-micro-model containing contextual hypotheses is necessary. Our methodological study examines whether empirical studies apply such a model. We propose that a theoretical base for country differences is well described in multilevel studies,…

Semantic Image Segmentation with Contextual Hierarchical Models.

PubMed

Seyedhosseini, Mojtaba; Tasdizen, Tolga

2016-05-01

Semantic segmentation is the problem of assigning an object label to each pixel. It unifies the image segmentation and object recognition problems. The importance of using contextual information in semantic segmentation frameworks has been widely realized in the field. We propose a contextual framework, called contextual hierarchical model (CHM), which learns contextual information in a hierarchical framework for semantic segmentation. At each level of the hierarchy, a classifier is trained based on downsampled input images and outputs of previous levels. Our model then incorporates the resulting multi-resolution contextual information into a classifier to segment the input image at original resolution. This training strategy allows for optimization of a joint posterior probability at multiple resolutions through the hierarchy. Contextual hierarchical model is purely based on the input image patches and does not make use of any fragments or shape examples. Hence, it is applicable to a variety of problems such as object segmentation and edge detection. We demonstrate that CHM performs at par with state-of-the-art on Stanford background and Weizmann horse datasets. It also outperforms state-of-the-art edge detection methods on NYU depth dataset and achieves state-of-the-art on Berkeley segmentation dataset (BSDS 500).

Contextual Factors Impacting a Pain Management Intervention.

PubMed

Alaloul, Fawwaz; Williams, Kimberly; Myers, John; Jones, Kayla Dlauren; Sullivan, Katelyn; Logsdon, M Cynthia

2017-09-01

To determine if findings from our preliminary study related to patient and nursing satisfaction with a pain management intervention could be replicated in a changed environment, and if contextual factors could impact the effectiveness of a pain management intervention on patient satisfaction with nursing staff's management of pain. A prospective, experimental design was used with six monthly assessments before, during, and after the intervention. Data were collected from 540 patients admitted to eight medical surgical and progressive care units and nurses that worked in these units at an academic health sciences center in the southern United States, from March to July 2015. The script-based, pain management communication intervention included three specific tactics: script-based communication, use of white boards, and hourly rounding. The Hospital Consumer Assessment of Healthcare Providers and Systems survey was used to assess two items: "pain is well controlled" and "staff did everything they could to help with pain." Contextual factors focused on the practice setting. Both scores for "pain is well controlled" (β = .028, p = 0.651) and scores for "staff did everything they could to help with pain" (β = .057,p = .385) did not change initially but then increased significantly and were sustained over time. Nurses had high levels of satisfaction with the intervention (M = 7.9, SD = 2.1) and compliance with the intervention (M = 8.0, SD = 1.9), and had little difficulty in implementing the intervention (M = 8.3, SD = 1.4). In terms of contextual factors, the number of beds on the unit and the number of patients being discharged negatively impacted scores for "pain is well controlled" and "staff did everything they could to help with pain." Hospital length of stay positively impacted scores for "pain is well controlled" by staff. Despite challenging contextual variables, the study extended the findings of an early preliminary study in showing the effectiveness of

The price of access: capitalization of neighborhood contextual factors

PubMed Central

2013-01-01

Background Studies of neighborhood context on health behavior have not considered that the health benefits of context may be ‘capitalized’ into, or included in, higher housing values. This study examines the associations of better neighborhood context with neighborhood housing values. Methods We use the third wave of Add Health (2000-2001) to estimate the association of neighborhood contextual variables and housing values first across then within income types. This is a census block group-level analysis. Results We find that neighborhood context, especially access to fruit and vegetable outlets, is capitalized into, or associated with, higher housing values. Fast food and convenience store access are associated with lower housing values. Capitalization differs by income quartile of the neighborhood. Even those in the poorest neighborhoods value access to fresh fruits and vegetables, and those in the wealthier neighborhoods value activity resources. All neighborhood incomes types place negative value on fast food access and convenience store access. Conclusions Access to health-related contextual attributes is capitalized into higher housing prices. Access to fresh fruits and vegetables is valued in neighborhoods of all income levels. Modeling these associations by neighborhood income levels helps explain the mixed results in the literature on the built environment in terms of linking health outcomes to access. PMID:23927010

Facets of contextual realism in quantum mechanics

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

Pan, Alok Kumar; Home, Dipankar

2011-09-23

In recent times, there is an upsurge of interest in demonstrating the quantum contextuality. In this proceedings, we explore the two different forms of arguments that have been used for showing the contextual character of quantum mechanics. First line of study concerns the violations of the noncontextual realist models by quantum mechanics, where second line of study that is qualitatively distinct from the earlier one, demonstrates the contextuality within the formalism of quantum mechanics.

The L-type voltage-gated calcium channel CaV1.2 mediates fear extinction and modulates synaptic tone in the lateral amygdala.

PubMed

Temme, Stephanie J; Murphy, Geoffrey G

2017-11-01

L-type voltage-gated calcium channels (LVGCCs) have been implicated in both the formation and the reduction of fear through Pavlovian fear conditioning and extinction. Despite the implication of LVGCCs in fear learning and extinction, studies of the individual LVGCC subtypes, Ca V 1.2 and Ca V 1.3, using transgenic mice have failed to find a role of either subtype in fear extinction. This discontinuity between the pharmacological studies of LVGCCs and the studies investigating individual subtype contributions could be due to the limited neuronal deletion pattern of the Ca V 1.2 conditional knockout mice previously studied to excitatory neurons in the forebrain. To investigate the effects of deletion of Ca V 1.2 in all neuronal populations, we generated Ca V 1.2 conditional knockout mice using the synapsin1 promoter to drive Cre recombinase expression. Pan-neuronal deletion of Ca V 1.2 did not alter basal anxiety or fear learning. However, pan-neuronal deletion of Ca V 1.2 resulted in a significant deficit in extinction of contextual fear, implicating LVGCCs, specifically Ca V 1.2, in extinction learning. Further exploration on the effects of deletion of Ca V 1.2 on inhibitory and excitatory input onto the principle neurons of the lateral amygdala revealed a significant shift in inhibitory/excitatory balance. Together these data illustrate an important role of Ca V 1.2 in fear extinction and the synaptic regulation of activity within the amygdala. © 2017 Temme and Murphy; Published by Cold Spring Harbor Laboratory Press.

Contextual Hub Analysis Tool (CHAT): A Cytoscape app for identifying contextually relevant hubs in biological networks.

PubMed

Muetze, Tanja; Goenawan, Ivan H; Wiencko, Heather L; Bernal-Llinares, Manuel; Bryan, Kenneth; Lynn, David J

2016-01-01

Highly connected nodes (hubs) in biological networks are topologically important to the structure of the network and have also been shown to be preferentially associated with a range of phenotypes of interest. The relative importance of a hub node, however, can change depending on the biological context. Here, we report a Cytoscape app, the Contextual Hub Analysis Tool (CHAT), which enables users to easily construct and visualize a network of interactions from a gene or protein list of interest, integrate contextual information, such as gene expression or mass spectrometry data, and identify hub nodes that are more highly connected to contextual nodes (e.g. genes or proteins that are differentially expressed) than expected by chance. In a case study, we use CHAT to construct a network of genes that are differentially expressed in Dengue fever, a viral infection. CHAT was used to identify and compare contextual and degree-based hubs in this network. The top 20 degree-based hubs were enriched in pathways related to the cell cycle and cancer, which is likely due to the fact that proteins involved in these processes tend to be highly connected in general. In comparison, the top 20 contextual hubs were enriched in pathways commonly observed in a viral infection including pathways related to the immune response to viral infection. This analysis shows that such contextual hubs are considerably more biologically relevant than degree-based hubs and that analyses which rely on the identification of hubs solely based on their connectivity may be biased towards nodes that are highly connected in general rather than in the specific context of interest. CHAT is available for Cytoscape 3.0+ and can be installed via the Cytoscape App Store ( http://apps.cytoscape.org/apps/chat).

Contextual modulation of primary visual cortex by auditory signals.

PubMed

Petro, L S; Paton, A T; Muckli, L

2017-02-19

Early visual cortex receives non-feedforward input from lateral and top-down connections (Muckli & Petro 2013 Curr. Opin. Neurobiol. 23, 195-201. (doi:10.1016/j.conb.2013.01.020)), including long-range projections from auditory areas. Early visual cortex can code for high-level auditory information, with neural patterns representing natural sound stimulation (Vetter et al. 2014 Curr. Biol. 24, 1256-1262. (doi:10.1016/j.cub.2014.04.020)). We discuss a number of questions arising from these findings. What is the adaptive function of bimodal representations in visual cortex? What type of information projects from auditory to visual cortex? What are the anatomical constraints of auditory information in V1, for example, periphery versus fovea, superficial versus deep cortical layers? Is there a putative neural mechanism we can infer from human neuroimaging data and recent theoretical accounts of cortex? We also present data showing we can read out high-level auditory information from the activation patterns of early visual cortex even when visual cortex receives simple visual stimulation, suggesting independent channels for visual and auditory signals in V1. We speculate which cellular mechanisms allow V1 to be contextually modulated by auditory input to facilitate perception, cognition and behaviour. Beyond cortical feedback that facilitates perception, we argue that there is also feedback serving counterfactual processing during imagery, dreaming and mind wandering, which is not relevant for immediate perception but for behaviour and cognition over a longer time frame.This article is part of the themed issue 'Auditory and visual scene analysis'. © 2017 The Authors.

Contextual modulation of primary visual cortex by auditory signals

PubMed Central

Paton, A. T.

2017-01-01

Early visual cortex receives non-feedforward input from lateral and top-down connections (Muckli & Petro 2013 Curr. Opin. Neurobiol. 23, 195–201. (doi:10.1016/j.conb.2013.01.020)), including long-range projections from auditory areas. Early visual cortex can code for high-level auditory information, with neural patterns representing natural sound stimulation (Vetter et al. 2014 Curr. Biol. 24, 1256–1262. (doi:10.1016/j.cub.2014.04.020)). We discuss a number of questions arising from these findings. What is the adaptive function of bimodal representations in visual cortex? What type of information projects from auditory to visual cortex? What are the anatomical constraints of auditory information in V1, for example, periphery versus fovea, superficial versus deep cortical layers? Is there a putative neural mechanism we can infer from human neuroimaging data and recent theoretical accounts of cortex? We also present data showing we can read out high-level auditory information from the activation patterns of early visual cortex even when visual cortex receives simple visual stimulation, suggesting independent channels for visual and auditory signals in V1. We speculate which cellular mechanisms allow V1 to be contextually modulated by auditory input to facilitate perception, cognition and behaviour. Beyond cortical feedback that facilitates perception, we argue that there is also feedback serving counterfactual processing during imagery, dreaming and mind wandering, which is not relevant for immediate perception but for behaviour and cognition over a longer time frame. This article is part of the themed issue ‘Auditory and visual scene analysis’. PMID:28044015

The transfer of Cfunc contextual control through equivalence relations.

PubMed

Perez, William F; Fidalgo, Adriana P; Kovac, Roberta; Nico, Yara C

2015-05-01

Derived relational responding is affected by contextual stimuli (Cfunc) that select specific stimulus functions. The present study investigated the transfer of Cfunc contextual control through equivalence relations by evaluating both (a) the maintenance of Cfunc contextual control after the expansion of a relational network, and (b) the establishment of novel contextual stimuli by the transfer of Cfunc contextual control through equivalence relations. Initially, equivalence relations were established and contingencies were arranged so that colors functioned as Cfunc stimuli controlling participants' key-pressing responses in the presence of any stimulus from a three-member equivalence network. To investigate the first research question, the three-member equivalence relations were expanded to five members and the novel members were presented with the Cfunc stimuli in the key-pressing task. To address the second goal of this study, the colors (Cfunc) were established as equivalent to certain line patterns. The transfer of contextual cue function (Cfunc) was tested replacing the colored backgrounds with line patterns in the key-pressing task. Results suggest that the Cfunc contextual control was transferred to novel stimuli that were added to the relational network. In addition, the line patterns indirectly acquired the contextual cue function (Cfunc) initially established for the colored backgrounds. The conceptual and applied implications of Cfunc contextual control are discussed. © Society for the Experimental Analysis of Behavior.

Contextual Sensing: Integrating Contextual Information with Human and Technical Geo-Sensor Information for Smart Cities

PubMed Central

Sagl, Günther; Resch, Bernd; Blaschke, Thomas

2015-01-01

In this article we critically discuss the challenge of integrating contextual information, in particular spatiotemporal contextual information, with human and technical sensor information, which we approach from a geospatial perspective. We start by highlighting the significance of context in general and spatiotemporal context in particular and introduce a smart city model of interactions between humans, the environment, and technology, with context at the common interface. We then focus on both the intentional and the unintentional sensing capabilities of today’s technologies and discuss current technological trends that we consider have the ability to enrich human and technical geo-sensor information with contextual detail. The different types of sensors used to collect contextual information are analyzed and sorted into three groups on the basis of names considering frequently used related terms, and characteristic contextual parameters. These three groups, namely technical in situ sensors, technical remote sensors, and human sensors are analyzed and linked to three dimensions involved in sensing (data generation, geographic phenomena, and type of sensing). In contrast to other scientific publications, we found a large number of technologies and applications using in situ and mobile technical sensors within the context of smart cities, and surprisingly limited use of remote sensing approaches. In this article we further provide a critical discussion of possible impacts and influences of both technical and human sensing approaches on society, pointing out that a larger number of sensors, increased fusion of information, and the use of standardized data formats and interfaces will not necessarily result in any improvement in the quality of life of the citizens of a smart city. This article seeks to improve our understanding of technical and human geo-sensing capabilities, and to demonstrate that the use of such sensors can facilitate the integration of different

Contextual Sensing: Integrating Contextual Information with Human and Technical Geo-Sensor Information for Smart Cities.

PubMed

Sagl, Günther; Resch, Bernd; Blaschke, Thomas

2015-07-14

In this article we critically discuss the challenge of integrating contextual information, in particular spatiotemporal contextual information, with human and technical sensor information, which we approach from a geospatial perspective. We start by highlighting the significance of context in general and spatiotemporal context in particular and introduce a smart city model of interactions between humans, the environment, and technology, with context at the common interface. We then focus on both the intentional and the unintentional sensing capabilities of today's technologies and discuss current technological trends that we consider have the ability to enrich human and technical geo-sensor information with contextual detail. The different types of sensors used to collect contextual information are analyzed and sorted into three groups on the basis of names considering frequently used related terms, and characteristic contextual parameters. These three groups, namely technical in situ sensors, technical remote sensors, and human sensors are analyzed and linked to three dimensions involved in sensing (data generation, geographic phenomena, and type of sensing). In contrast to other scientific publications, we found a large number of technologies and applications using in situ and mobile technical sensors within the context of smart cities, and surprisingly limited use of remote sensing approaches. In this article we further provide a critical discussion of possible impacts and influences of both technical and human sensing approaches on society, pointing out that a larger number of sensors, increased fusion of information, and the use of standardized data formats and interfaces will not necessarily result in any improvement in the quality of life of the citizens of a smart city. This article seeks to improve our understanding of technical and human geo-sensing capabilities, and to demonstrate that the use of such sensors can facilitate the integration of different

Contextual Cueing Effects across the Lifespan

ERIC Educational Resources Information Center

Merrill, Edward C.; Conners, Frances A.; Roskos, Beverly; Klinger, Mark R.; Klinger, Laura Grofer

2013-01-01

The authors evaluated age-related variations in contextual cueing, which reflects the extent to which visuospatial regularities can facilitate search for a target. Previous research produced inconsistent results regarding contextual cueing effects in young children and in older adults, and no study has investigated the phenomenon across the life…

Contextual Factors in Adolescent Substance Use.

ERIC Educational Resources Information Center

Hochhauser, Mark; And Others

Research on adolescent substance use has focused on prevalence and incidence; however, contextual factors have been largely ignored. A survey of 155 adolescents from a Minneapolis suburb was conducted to assess contextual factors affecting adolescent substance use. Subjects reported their use of alcohol, cigarettes, and marihuana with respect to…

Race Differences in Cardiac Catheterization: The Role of Social Contextual Variables

PubMed Central

Kressin, Nancy R.

2010-01-01

BACKGROUND Race differences in the receipt of invasive cardiac procedures are well-documented but the etiology remains poorly understood. OBJECTIVE We examined how social contextual variables were related to race differences in the likelihood of receiving cardiac catheterization in a sample of veterans who were recommended to undergo the procedure by a physician. DESIGN Prospective observational cohort study. PARTICIPANTS A subsample from a study examining race disparities in cardiac catheterization of 48 Black/African American and 189 White veterans who were recommended by a physician to undergo cardiac catheterization. MEASURES We assessed social contextual variables (e.g., knowing somebody who had the procedure, being encouraged by family or friends), clinical variables (e.g., hypertension, maximal medical therapy), and if participants received cardiac catheterization at any point during the study. KEY RESULTS Blacks/African Americans were less likely to undergo cardiac catheterization compared to Whites even after controlling for age, education, and clinical variables (OR = 0.31; 95% CI, 0.13, 0.75). After controlling for demographic and clinical variables, three social contextual variables were significantly related to increased likelihood of receiving catheterization: knowing someone who had undergone the procedure (OR = 3.14; 95% CI, 1.70, 8.74), social support (OR = 2.05; 95% CI, 1.17, 2.78), and being encouraged by family to have procedure (OR = 1.45; 95% CI, 1.08, 1.90). After adding the social contextual variables, race was no longer significantly related to the likelihood of receiving catheterization, thus suggesting that social context plays an important role in the relationship between race and cardiac catheterization. CONCLUSIONS Our results suggest that social contextual factors are related to the likelihood of receiving recommended care. In addition, accounting for these relationships attenuated the observed race disparities between

Stimulus Equivalence, Generalization, and Contextual Stimulus Control in Verbal Classes

PubMed Central

Sigurðardóttir, Zuilma Gabriela; Mackay, Harry A; Green, Gina

2012-01-01

Stimulus generalization and contextual control affect the development of equivalence classes. Experiment 1 demonstrated primary stimulus generalization from the members of trained equivalence classes. Adults were taught to match six spoken Icelandic nouns and corresponding printed words and pictures to one another in computerized three-choice matching-to-sample tasks. Tests confirmed that six equivalence classes had formed. Without further training, plural forms of the stimuli were presented in tests for all matching performances. All participants demonstrated virtually errorless performances. In Experiment 2, classifications of the nouns used in Experiment 1 were brought under contextual control. Three nouns were feminine and three were masculine. The match-to-sample training taught participants to select a comparison of the same number as the sample (i.e., singular or plural) in the presence of contextual stimulus A regardless of noun gender. Concurrently, in the presence of contextual stimulus B, participants were taught to select a comparison of the same gender as the sample (i.e., feminine or masculine), regardless of number. Generalization was assessed using a card-sorting test. All participants eventually sorted the cards correctly into gender and number stimulus classes. When printed words used in training were replaced by their picture equivalents, participants demonstrated almost errorless performances. PMID:22754102

Contextual Factors and Effective School Improvement

ERIC Educational Resources Information Center

Sun, Hechuan; Creemers, Bert P. M.; de Jong, Rob

2007-01-01

This research provides policy-makers, researchers, and educators at all levels with a glimpse of the contextual influence on effective school improvement (ESI) in 8 European countries. What are the factors at the contextual level, particularly at the national level, which influence ESI? Are there any similarities or differences between the…

Contextual control of conditioning is not affected by extinction in a behavioral task with humans.

PubMed

Nelson, James Byron; Lamoureux, Jeffrey A

2015-06-01

The Attentional Theory of Context Processing (ATCP) states that extinction will arouse attention to contexts resulting in learning becoming contextually controlled. Participants learned to suppress responding to colored sensors in a video-game task where contexts were provided by different gameplay backgrounds. Four experiments assessed the contextual control of simple excitatory learning acquired to a test stimulus (T) after (Exp. 1) or during (Exp. 2-4) extinction of another stimulus (X). Experiment 1 produced no evidence of contextual control of T, though renewal to X was present both at the time T was trained and tested. In Experiment 2 no contextual control of T was evident when X underwent extensive conditioning and extinction. In Experiment 3 no contextual control of T was evident after extensive conditioning and extinction of X, and renewal to X was present. In Experiment 4 contextual control was evident to T, but it neither depended upon nor was enhanced by extinction of X. The results presented here appear to limit the generality of ATCP.

Contextual Advantage for State Discrimination

NASA Astrophysics Data System (ADS)

Schmid, David; Spekkens, Robert W.

2018-02-01

Finding quantitative aspects of quantum phenomena which cannot be explained by any classical model has foundational importance for understanding the boundary between classical and quantum theory. It also has practical significance for identifying information processing tasks for which those phenomena provide a quantum advantage. Using the framework of generalized noncontextuality as our notion of classicality, we find one such nonclassical feature within the phenomenology of quantum minimum-error state discrimination. Namely, we identify quantitative limits on the success probability for minimum-error state discrimination in any experiment described by a noncontextual ontological model. These constraints constitute noncontextuality inequalities that are violated by quantum theory, and this violation implies a quantum advantage for state discrimination relative to noncontextual models. Furthermore, our noncontextuality inequalities are robust to noise and are operationally formulated, so that any experimental violation of the inequalities is a witness of contextuality, independently of the validity of quantum theory. Along the way, we introduce new methods for analyzing noncontextuality scenarios and demonstrate a tight connection between our minimum-error state discrimination scenario and a Bell scenario.

Contextual cost: when a visual-search target is not where it should be.

PubMed

Makovski, Tal; Jiang, Yuhong V

2010-02-01

Visual search is often facilitated when the search display occasionally repeats, revealing a contextual-cueing effect. According to the associative-learning account, contextual cueing arises from associating the display configuration with the target location. However, recent findings emphasizing the importance of local context near the target have given rise to the possibility that low-level repetition priming may account for the contextual-cueing effect. This study distinguishes associative learning from local repetition priming by testing whether search is directed toward a target's expected location, even when the target is relocated. After participants searched for a T among Ls in displays that repeated 24 times, they completed a transfer session where the target was relocated locally to a previously blank location (Experiment 1) or to an adjacent distractor location (Experiment 2). Results revealed that contextual cueing decreased as the target appeared farther away from its expected location, ultimately resulting in a contextual cost when the target swapped locations with a local distractor. We conclude that target predictability is a key factor in contextual cueing.

Facilitating Student Learning through Contextualization. CCRC Working Paper No. 29

ERIC Educational Resources Information Center

Perin, Dolores

2011-01-01

This paper is a literature review that explores the nature and effectiveness of contextualization as a way to improve outcomes for academically underprepared college students. Two forms of contextualization have been studied: "contextualized" and "integrated" instruction. There is more descriptive work on the contextualization of basic skills than…

Effect of glycosylation on an immunodominant region in the V1V2 variable domain of the HIV-1 envelope gp120 protein

DOE PAGES

Tian, Jianhui; Lopez, Cesar Augusto; Derdeyn, Cynthia A.; ...

2016-10-07

Heavy glycosylation of the envelope (Env) surface subunit, gp120, is a key adaptation of HIV-1; however, the precise effects of glycosylation on the folding, conformation and dynamics of this protein are poorly understood. Here we explore the patterns of HIV-1 Env gp120 glycosylation, and particularly the enrichment in glycosylation sites proximal to the disulfide linkages at the base of the surface-exposed variable domains. To dissect the influence of glycans on the conformation these regions, we focused on an antigenic peptide fragment from a disulfide bridge-bounded region spanning the V1 and V2 hyper-variable domains of HIV-1 gp120. We used replica exchangemore » molecular dynamics (MD) simulations to investigate how glycosylation influences its conformation and stability. Simulations were performed with and without N-linked glycosylation at two sites that are highly conserved across HIV-1 isolates (N156 and N160); both are contacts for recognition by V1V2-targeted broadly neutralizing antibodies against HIV-1. Glycosylation stabilized the pre-existing conformations of this peptide construct, reduced its propensity to adopt other secondary structures, and provided resistance against thermal unfolding. Simulations performed in the context of the Env trimer also indicated that glycosylation reduces flexibility of the V1V2 region, and provided insight into glycan-glycan interactions in this region. These stabilizing effects were influenced by a combination of factors, including the presence of a disulfide bond between the Cysteines at 131 and 157, which increased the formation of beta-strands. Together, these results provide a mechanism for conservation of disulfide linkage proximal glycosylation adjacent to the variable domains of gp120 and begin to explain how this could be exploited to enhance the immunogenicity of those regions. Furthermore, these studies suggest that glycopeptide immunogens can be designed to stabilize the most relevant Env conformations to

Effect of glycosylation on an immunodominant region in the V1V2 variable domain of the HIV-1 envelope gp120 protein

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

Tian, Jianhui; Lopez, Cesar Augusto; Derdeyn, Cynthia A.

Heavy glycosylation of the envelope (Env) surface subunit, gp120, is a key adaptation of HIV-1; however, the precise effects of glycosylation on the folding, conformation and dynamics of this protein are poorly understood. Here we explore the patterns of HIV-1 Env gp120 glycosylation, and particularly the enrichment in glycosylation sites proximal to the disulfide linkages at the base of the surface-exposed variable domains. To dissect the influence of glycans on the conformation these regions, we focused on an antigenic peptide fragment from a disulfide bridge-bounded region spanning the V1 and V2 hyper-variable domains of HIV-1 gp120. We used replica exchangemore » molecular dynamics (MD) simulations to investigate how glycosylation influences its conformation and stability. Simulations were performed with and without N-linked glycosylation at two sites that are highly conserved across HIV-1 isolates (N156 and N160); both are contacts for recognition by V1V2-targeted broadly neutralizing antibodies against HIV-1. Glycosylation stabilized the pre-existing conformations of this peptide construct, reduced its propensity to adopt other secondary structures, and provided resistance against thermal unfolding. Simulations performed in the context of the Env trimer also indicated that glycosylation reduces flexibility of the V1V2 region, and provided insight into glycan-glycan interactions in this region. These stabilizing effects were influenced by a combination of factors, including the presence of a disulfide bond between the Cysteines at 131 and 157, which increased the formation of beta-strands. Together, these results provide a mechanism for conservation of disulfide linkage proximal glycosylation adjacent to the variable domains of gp120 and begin to explain how this could be exploited to enhance the immunogenicity of those regions. Furthermore, these studies suggest that glycopeptide immunogens can be designed to stabilize the most relevant Env conformations to

Thalamic nuclei convey diverse contextual information to layer 1 of visual cortex

PubMed Central

Imhof, Fabia; Martini, Francisco J.; Hofer, Sonja B.

2017-01-01

Sensory perception depends on the context within which a stimulus occurs. Prevailing models emphasize cortical feedback as the source of contextual modulation. However, higher-order thalamic nuclei, such as the pulvinar, interconnect with many cortical and subcortical areas, suggesting a role for the thalamus in providing sensory and behavioral context – yet the nature of the signals conveyed to cortex by higher-order thalamus remains poorly understood. Here we use axonal calcium imaging to measure information provided to visual cortex by the pulvinar equivalent in mice, the lateral posterior nucleus (LP), as well as the dorsolateral geniculate nucleus (dLGN). We found that dLGN conveys retinotopically precise visual signals, while LP provides distributed information from the visual scene. Both LP and dLGN projections carry locomotion signals. However, while dLGN inputs often respond to positive combinations of running and visual flow speed, LP signals discrepancies between self-generated and external visual motion. This higher-order thalamic nucleus therefore conveys diverse contextual signals that inform visual cortex about visual scene changes not predicted by the animal’s own actions. PMID:26691828

On Contextuality.

ERIC Educational Resources Information Center

Thayer-Bacon, Barbara J.

This exploration of what feminism has to contribute to pragmatism, and vice versa, considers the idea of contextuality through an examination of the role of current pragmatists, such as Cornel West and Richard Rorty, and current feminists, including Charlene Haddock Siegfried, Maxine Greene, and Seyla Benhabib. To set the stage historically for…

Divergent biophysical properties, gating mechanisms, and possible functions of the two skeletal muscle Ca(V)1.1 calcium channel splice variants.

PubMed

Tuluc, Petronel; Flucher, Bernhard E

2011-12-01

Voltage-gated calcium channels are multi-subunit protein complexes that specifically allow calcium ions to enter the cell in response to membrane depolarization. But, for many years it seemed that the skeletal muscle calcium channel Ca(V)1.1 is the exception. The classical splice variant Ca(V)1.1a activates slowly, has a very small current amplitude and poor voltage sensitivity. In fact adult muscle fibers work perfectly well even in the absence of calcium influx. Recently a new splice variant of the skeletal muscle calcium channel Ca(V)1.1e has been characterized. The lack of the 19 amino acid exon 29 in this splice variant results in a rapidly activating calcium channel with high current amplitude and good voltage sensitivity. Ca(V)1.1e is the dominant channel in embryonic muscle, where the expression of this high calcium-conducting Ca(V)1.1 isoform readily explains developmental processes depending on L-type calcium currents. Moreover, the availability of these two structurally similar but functionally distinct channel variants facilitates the analysis of the molecular mechanisms underlying the unique current properties of the classical Ca(V)1.1a channel.

Extending the Trans-Contextual Model in Physical Education and Leisure-Time Contexts: Examining the Role of Basic Psychological Need Satisfaction

ERIC Educational Resources Information Center

Barkoukis, Vassilis; Hagger, Martin S.; Lambropoulos, George; Tsorbatzoudis, Haralambos

2010-01-01

Background: The trans-contextual model (TCM) is an integrated model of motivation that aims to explain the processes by which agentic support for autonomous motivation in physical education promotes autonomous motivation and physical activity in a leisure-time context. It is proposed that perceived support for autonomous motivation in physical…

Simple method for experimentally testing any form of quantum contextuality

NASA Astrophysics Data System (ADS)

Cabello, Adán

2016-03-01

Contextuality provides a unifying paradigm for nonclassical aspects of quantum probabilities and resources of quantum information. Unfortunately, most forms of quantum contextuality remain experimentally unexplored due to the difficulty of performing sequences of projective measurements on individual quantum systems. Here we show that two-point correlations between binary compatible observables are sufficient to reveal any form of contextuality. This allows us to design simple experiments that are more robust against imperfections and easier to analyze, thus opening the door for observing interesting forms of contextuality, including those requiring quantum systems of high dimensions. In addition, it allows us to connect contextuality to communication complexity scenarios and reformulate a recent result relating contextuality and quantum computation.

A dissociation between renewal and contextual fear conditioning in juvenile rats.

PubMed

Park, Chun Hui J; Ganella, Despina E; Kim, Jee Hyun

2017-05-01

We investigated whether juvenile rats do not express renewal following extinction of conditioned fear due to their inability to form a long-term contextual fear memory. In experiment 1, postnatal day (P) 18 and 25 rats received 3 white-noise and footshock pairings, followed by 60 white-noise alone presentations the next day. When tested in a different context to extinction, P25 rats displayed renewal whereas P18 rats did not. Experiments 2A and 2B surprisingly showed that P18 and P25 rats do not show differences in contextual and cued fear, regardless of the conditioning-test intervals and the number of white-noise-footshock pairings received. Finally, we observed age differences in contextual fear when P25 rats were weaned at P21 in experiment 3. These results indicate that the developmental dissociation observed in renewal of extinguished fear is not related to the widely believed late emergence of contextual fear learning. © 2017 Wiley Periodicals, Inc.

Chronic fluoxetine dissociates contextual from auditory fear memory.

PubMed

Sanders, Jeff; Mayford, Mark

2016-10-06

Fluoxetine is a medication used to treat Major Depressive Disorder and other psychiatric conditions. These experiments studied the effects of chronic fluoxetine treatment on the contextual versus auditory fear memory of mice. We found that chronic fluoxetine treatment of adult mice impaired their contextual fear memory, but spared auditory fear memory. Hippocampal perineuronal nets, which are involved in contextual fear memory plasticity, were unaltered by fluoxetine treatment. These data point to a selective inability to form contextual fear memory as a result of fluoxetine treatment, and they suggest that a blunting of hippocampal-mediated aversive memory may be a therapeutic action for this medication. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Rapid contextual conditioning in autoshaping.

PubMed

Balsam, P D; Schwartz, A L

1981-10-01

Two experiments are reported which investigate the speed of contextual conditioning in autoshaping. In both experiments, a procedure was employed in which ring doves were magazine trained in one context prior to the manipulation of background values in a second context. In Experiment 1, subjects were exposed to 4, 8, 64, 128, or 256 US-only presentations prior to autoshaping. Acquisition speed and maintained response measures were monotonically related to the number of pretraining trials. Subjects in Group 4 acquired the key-peck response fastest, and retardation was maximal within 64 pretraining trials. In Experiment 2, subjects given 20 pretraining trials were significantly more retarded than subjects given 2 pretraining trials, but only when pretraining and testing were conducted in the same context. Overall, the results of these experiments show that in autoshaping, contextual conditioning is very rapid; this demonstrates the plausibility of theoretical accounts of Pavlovian conditioning which assert that the development of the conditioned response depends on the associative values of both the CS and background stimuli.

Contextual interference processing during fast categorisations of facial expressions.

PubMed

Frühholz, Sascha; Trautmann-Lengsfeld, Sina A; Herrmann, Manfred

2011-09-01

We examined interference effects of emotionally associated background colours during fast valence categorisations of negative, neutral and positive expressions. According to implicitly learned colour-emotion associations, facial expressions were presented with colours that either matched the valence of these expressions or not. Experiment 1 included infrequent non-matching trials and Experiment 2 a balanced ratio of matching and non-matching trials. Besides general modulatory effects of contextual features on the processing of facial expressions, we found differential effects depending on the valance of target facial expressions. Whereas performance accuracy was mainly affected for neutral expressions, performance speed was specifically modulated by emotional expressions indicating some susceptibility of emotional expressions to contextual features. Experiment 3 used two further colour-emotion combinations, but revealed only marginal interference effects most likely due to missing colour-emotion associations. The results are discussed with respect to inherent processing demands of emotional and neutral expressions and their susceptibility to contextual interference.

The role of meaning in contextual cueing: evidence from chess expertise.

PubMed

Brockmole, James R; Hambrick, David Z; Windisch, David J; Henderson, John M

2008-01-01

In contextual cueing, the position of a search target is learned over repeated exposures to a visual display. The strength of this effect varies across stimulus types. For example, real-world scene contexts give rise to larger search benefits than contexts composed of letters or shapes. We investigated whether such differences in learning can be at least partially explained by the degree of semantic meaning associated with a context independently of the nature of the visual information available (which also varies across stimulus types). Chess boards served as the learning context as their meaningfulness depends on the observer's knowledge of the game. In Experiment 1, boards depicted actual game play, and search benefits for repeated boards were 4 times greater for experts than for novices. In Experiment 2, search benefits among experts were halved when less meaningful randomly generated boards were used. Thus, stimulus meaningfulness independently contributes to learning context-target associations.

Contextual cueing in 3D visual search depends on representations in planar-, not depth-defined space.

PubMed

Zang, Xuelian; Shi, Zhuanghua; Müller, Hermann J; Conci, Markus

2017-05-01

Learning of spatial inter-item associations can speed up visual search in everyday life, an effect referred to as contextual cueing (Chun & Jiang, 1998). Whereas previous studies investigated contextual cueing primarily using 2D layouts, the current study examined how 3D depth influences contextual learning in visual search. In two experiments, the search items were presented evenly distributed across front and back planes in an initial training session. In the subsequent test session, the search items were either swapped between the front and back planes (Experiment 1) or between the left and right halves (Experiment 2) of the displays. The results showed that repeated spatial contexts were learned efficiently under 3D viewing conditions, facilitating search in the training sessions, in both experiments. Importantly, contextual cueing remained robust and virtually unaffected following the swap of depth planes in Experiment 1, but it was substantially reduced (to nonsignificant levels) following the left-right side swap in Experiment 2. This result pattern indicates that spatial, but not depth, inter-item variations limit effective contextual guidance. Restated, contextual cueing (even under 3D viewing conditions) is primarily based on 2D inter-item associations, while depth-defined spatial regularities are probably not encoded during contextual learning. Hence, changing the depth relations does not impact the cueing effect.

Object based implicit contextual learning: a study of eye movements.

PubMed

van Asselen, Marieke; Sampaio, Joana; Pina, Ana; Castelo-Branco, Miguel

2011-02-01

Implicit contextual cueing refers to a top-down mechanism in which visual search is facilitated by learned contextual features. In the current study we aimed to investigate the mechanism underlying implicit contextual learning using object information as a contextual cue. Therefore, we measured eye movements during an object-based contextual cueing task. We demonstrated that visual search is facilitated by repeated object information and that this reduction in response times is associated with shorter fixation durations. This indicates that by memorizing associations between objects in our environment we can recognize objects faster, thereby facilitating visual search.

Social Salience Discriminates Learnability of Contextual Cues in an Artificial Language.

PubMed

Rácz, Péter; Hay, Jennifer B; Pierrehumbert, Janet B

2017-01-01

We investigate the learning of contextual meaning by adults in an artificial language. Contextual meaning here refers to the non-denotative contextual information that speakers attach to a linguistic construction. Through a series of short games, played online, we test how well adults can learn different contextual meanings for a word-formation pattern in an artificial language. We look at whether learning contextual meanings depends on the social salience of the context, whether our players interpret these contexts generally, and whether the learned meaning is generalized to new words. Our results show that adults are capable of learning contextual meaning if the context is socially salient, coherent, and interpretable. Once a contextual meaning is recognized, it is readily generalized to related forms and contexts.

Social Salience Discriminates Learnability of Contextual Cues in an Artificial Language

PubMed Central

Rácz, Péter; Hay, Jennifer B.; Pierrehumbert, Janet B.

2017-01-01

We investigate the learning of contextual meaning by adults in an artificial language. Contextual meaning here refers to the non-denotative contextual information that speakers attach to a linguistic construction. Through a series of short games, played online, we test how well adults can learn different contextual meanings for a word-formation pattern in an artificial language. We look at whether learning contextual meanings depends on the social salience of the context, whether our players interpret these contexts generally, and whether the learned meaning is generalized to new words. Our results show that adults are capable of learning contextual meaning if the context is socially salient, coherent, and interpretable. Once a contextual meaning is recognized, it is readily generalized to related forms and contexts. PMID:28194122

The impact of distracter-target similarity on contextual cueing effects of children and adults.

PubMed

Yang, Yingying; Merrill, Edward C

2014-05-01

Contextual cueing reflects a memory-based attentional guidance process that develops through repeated exposure to displays in which a target location has been consistently paired with a specific context. In two experiments, we compared 20 younger children's (6-7 years old), 20 older children's (9-10 years old), and 20 young adults' (18-21 years old) abilities to acquire contextual cueing effects from displays in which half of the distracters predicted the location of the target and half did not. Across experiments, we varied the similarity between the predictive and nonpredictive distracters and the target. In Experiment 1, the predictive distracters were visually similar to the target and dissimilar from the nonpredictive distracters. In Experiment 2, the nonpredictive distracters were also similar to the target and predictive distracters. All three age groups exhibited contextual cueing in Experiment 1, although the effect was not as strong for the younger children relative to older children and adults. All participants exhibited weaker contextual cueing effects in Experiment 2, with the younger children not exhibiting significant contextual cueing at all. Apparently, when search processes could not be guided to the predictive distracters on the basis of salient stimulus features, younger children in particular experienced difficulty in implicitly identifying and using aspects of the context to facilitate with the acquisition of contextual cueing effects. Copyright © 2013 Elsevier Inc. All rights reserved.

Sex- and dose-dependent effects of calcium ion irradiation on behavioral performance of B6D2F1 mice during contextual fear conditioning training

NASA Astrophysics Data System (ADS)

Raber, Jacob; Weber, Sydney J.; Kronenberg, Amy; Turker, Mitchell S.

2016-06-01

The space radiation environment includes energetic charged particles that may impact behavioral and cognitive performance. The relationship between the dose and the ionization density of the various types of charged particles (expressed as linear energy transfer or LET), and cognitive performance is complex. In our earlier work, whole body exposure to 28Si ions (263 MeV/n, LET = 78keV / μ m ; 1.6 Gy) affected contextual fear memory in C57BL/6J × DBA2/J F1 (B6D2F1) mice three months following irradiation but this was not the case following exposure to 48Ti ions (1 GeV/n, LET = 107keV / μ m ; 0.2 or 0.4 Gy). As an increased understanding of the impact of charged particle exposures is critical for assessment of risk to the CNS of astronauts during and following missions, in this study we used 40Ca ion beams (942 MeV/n, LET = 90keV / μm) to determine the behavioral and cognitive effects for the LET region between that of Si ions and Ti ions. 40Ca ion exposure reduced baseline activity in a novel environment in a dose-dependent manner, which suggests reduced motivation to explore and/or a diminished level of curiosity in a novel environment. In addition, exposure to 40Ca ions had sex-dependent effects on response to shock. 40Ca ion irradiation reduced the response to shock in female, but not male, mice. In contrast, 40Ca ion irradiation did not affect fear learning, memory, or extinction of fear memory for either gender at the doses employed in this study. Thus 40Ca ion irradiation affected behavioral, but not cognitive, performance. The effects of 40Ca ion irradiation on behavioral performance are relevant, as a combination of novelty and aversive environmental stimuli is pertinent to conditions experienced by astronauts during and following space missions.

Sex- and dose-dependent effects of calcium ion irradiation on behavioral performance of B6D2F1 mice during contextual fear conditioning training.

PubMed

Raber, Jacob; Weber, Sydney J; Kronenberg, Amy; Turker, Mitchell S

2016-06-01

The space radiation environment includes energetic charged particles that may impact behavioral and cognitive performance. The relationship between the dose and the ionization density of the various types of charged particles (expressed as linear energy transfer or LET), and cognitive performance is complex. In our earlier work, whole body exposure to (28)Si ions (263 MeV/n, LET=78keV/μm; 1.6 Gy) affected contextual fear memory in C57BL/6J × DBA2/J F1 (B6D2F1) mice three months following irradiation but this was not the case following exposure to (48)Ti ions (1 GeV/n, LET=107keV/μm; 0.2 or 0.4 Gy). As an increased understanding of the impact of charged particle exposures is critical for assessment of risk to the CNS of astronauts during and following missions, in this study we used (40)Ca ion beams (942 MeV/n, LET=90keV/μm) to determine the behavioral and cognitive effects for the LET region between that of Si ions and Ti ions. (40)Ca ion exposure reduced baseline activity in a novel environment in a dose-dependent manner, which suggests reduced motivation to explore and/or a diminished level of curiosity in a novel environment. In addition, exposure to (40)Ca ions had sex-dependent effects on response to shock. (40)Ca ion irradiation reduced the response to shock in female, but not male, mice. In contrast, (40)Ca ion irradiation did not affect fear learning, memory, or extinction of fear memory for either gender at the doses employed in this study. Thus (40)Ca ion irradiation affected behavioral, but not cognitive, performance. The effects of (40)Ca ion irradiation on behavioral performance are relevant, as a combination of novelty and aversive environmental stimuli is pertinent to conditions experienced by astronauts during and following space missions. Copyright © 2016 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.

HYDRATE v1.5 OPTION OF TOUGH+ v1.5

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

Moridis, George

HYDRATE v1.5 is a numerical code that for the simulation of the behavior of hydrate-bearing geologic systems, and represents the third update of the code since its first release [Moridis et al., 2008]. It is an option of TOUGH+ v1.5 [Moridis and Pruess, 2014], a successor to the TOUGH2 [Pruess et al., 1999, 2012] family of codes for multi-component, multiphase fluid and heat flow developed at the Lawrence Berkeley National Laboratory. HYDRATE v1.5 needs the TOUGH+ v1.5 core code in order to compile and execute. It is written in standard FORTRAN 95/2003, and can be run on any computational platformmore » (workstation, PC, Macintosh) for which such compilers are available. By solving the coupled equations of mass and heat balance, the fully operational TOUGH+HYDRATE code can model the non-isothermal gas release, phase behavior and flow of fluids and heat under conditions typical of common natural CH 4-hydrate deposits (i.e., in the permafrost and in deep ocean sediments) in complex geological media at any scale (from laboratory to reservoir) at which Darcy's law is valid. TOUGH+HYDRATE v1.5 includes both an equilibrium and a kinetic model of hydrate formation and dissociation. The model accounts for heat and up to four mass components, i.e., water, CH 4, hydrate, and water-soluble inhibitors such as salts or alcohols. These are partitioned among four possible phases (gas phase, liquid phase, ice phase and hydrate phase). Hydrate dissociation or formation, phase changes and the corresponding thermal effects are fully described, as are the effects of inhibitors. The model can describe all possible hydrate dissociation mechanisms, i.e., depressurization, thermal stimulation, salting-out effects and inhibitor-induced effects.« less

The effects of acute nicotine on contextual safety discrimination.

PubMed

Kutlu, Munir G; Oliver, Chicora; Gould, Thomas J

2014-11-01

Anxiety disorders, such as post-traumatic stress disorder (PTSD), may be related to an inability to distinguish safe versus threatening environments and to extinguish fear memories. Given the high rate of cigarette smoking in patients with PTSD, as well as the recent finding that an acute dose of nicotine impairs extinction of contextual fear memory, we conducted a series of experiments to investigate the effect of acute nicotine in an animal model of contextual safety discrimination. Following saline or nicotine (at 0.0275, 0.045, 0.09 and 0.18 mg/kg) administration, C57BL/6J mice were trained in a contextual discrimination paradigm, in which the subjects received presentations of conditioned stimuli (CS) that co-terminated with a foot-shock in one context (context A (CXA)) and only CS presentations without foot-shock in a different context (context B (CXB)). Therefore, CXA was designated as the 'dangerous context', whereas CXB was designated as the 'safe context'. Our results suggested that saline-treated animals showed a strong discrimination between dangerous and safe contexts, while acute nicotine dose-dependently impaired contextual safety discrimination (Experiment 1). Furthermore, our results demonstrate that nicotine-induced impairment of contextual safety discrimination learning was not a result of increased generalized freezing (Experiment 2) or contingent on the common CS presentations in both contexts (Experiment 3). Finally, our results show that increasing the temporal gap between CXA and CXB during training abolished the impairing effects of nicotine (Experiment 4). The findings of this study may help link nicotine exposure to the safety learning deficits seen in anxiety disorder and PTSD patients. © The Author(s) 2014.

Time-dependent effects of cortisol on the contextualization of emotional memories.

PubMed

van Ast, Vanessa A; Cornelisse, Sandra; Meeter, Martijn; Joëls, Marian; Kindt, Merel

2013-12-01

The inability to store fearful memories into their original encoding context is considered to be an important vulnerability factor for the development of anxiety disorders like posttraumatic stress disorder. Altered memory contextualization most likely involves effects of the stress hormone cortisol, acting via receptors located in the memory neurocircuitry. Cortisol via these receptors induces rapid nongenomic effects followed by slower genomic effects, which are thought to modulate cognitive function in opposite, complementary ways. Here, we targeted these time-dependent effects of cortisol during memory encoding and tested subsequent contextualization of emotional and neutral memories. In a double-blind, placebo-controlled design, 64 men were randomly assigned to one of three groups: 1) received 10 mg hydrocortisone 30 minutes (rapid cortisol effects) before a memory encoding task; 2) received 10 mg hydrocortisone 210 minutes (slow cortisol) before a memory encoding task; or 3) received placebo at both times. During encoding, participants were presented with neutral and emotional words in unique background pictures. Approximately 24 hours later, context dependency of their memories was assessed. Recognition data revealed that cortisol's rapid effects impair emotional memory contextualization, while cortisol's slow effects enhance it. Neutral memory contextualization remained unaltered by cortisol, irrespective of the timing of the drug. This study shows distinct time-dependent effects of cortisol on the contextualization of specifically emotional memories. The results suggest that rapid effects of cortisol may lead to impaired emotional memory contextualization, while slow effects of cortisol may confer protection against emotional memory generalization. © 2013 Society of Biological Psychiatry.

CONTEXTUAL INTERFERENCE AND INTROVERSION/EXTRAVERSION IN MOTOR LEARNING.

PubMed

Meira, Cassio M; Fairbrother, Jeffrey T; Perez, Carlos R

2015-10-01

The Introversion/Extraversion dimension may interact with contextual interference, as random and blocked practice schedules imply distinct levels of variation. This study investigated the effect of different practice schedules in the acquisition of a motor skill in extraverts and introverts. Forty male undergraduate students (M = 24.3 yr., SD = 5.6) were classified as extraverts (n = 20) and introverts (n = 20) by the Eysenck Personality Questionnaire and allocated in one of two practice schedules with different levels of contextual interference: blocked (low contextual interference) and random (high contextual interference). Half of each group was assigned to a blocked practice schedule, and the other half was assigned to a random practice schedule. The design had two phases: acquisition and transfer (5 min. and 24 hr.). The participants learned variations of a sequential timing keypressing task. Each variation required the same sequence but different timing; three variations were used in acquisition, and one variation of intermediate length was used in transfer. Results for absolute error and overall timing error (root mean square error) indicated that the contextual interference effect was more pronounced for introverts. In addition, introverts who practiced according to the blocked schedule committed more errors during the 24-hr. transfer, suggesting that introverts did not appear to be challenged by a low contextual interference practice schedule.

Self-verification and contextualized self-views.

PubMed

Chen, Serena; English, Tammy; Peng, Kaiping

2006-07-01

Whereas most self-verification research has focused on people's desire to verify their global self-conceptions, the present studies examined self-verification with regard to contextualized selfviews-views of the self in particular situations and relationships. It was hypothesized that individuals whose core self-conceptions include contextualized self-views should seek to verify these self-views. In Study 1, the more individuals defined the self in dialectical terms, the more their judgments were biased in favor of verifying over nonverifying feedback about a negative, situation-specific self-view. In Study 2, consistent with research on gender differences in the importance of relationships to the self-concept, women but not men showed a similar bias toward feedback about a negative, relationship-specific self-view, a pattern not seen for global self-views. Together, the results support the notion that self-verification occurs for core self-conceptions, whatever form(s) they may take. Individual differences in self-verification and the nature of selfhood and authenticity are discussed.

Explaining the DAMPE data with scalar dark matter and gauged U(1)_{L_e-L_μ } interaction

NASA Astrophysics Data System (ADS)

Cao, Junjie; Feng, Lei; Guo, Xiaofei; Shang, Liangliang; Wang, Fei; Wu, Peiwen; Zu, Lei

2018-03-01

Inspired by the peak structure observed by recent DAMPE experiment in e^+e^- cosmic-ray spectrum, we consider a scalar dark matter (DM) model with gauged U(1)_{L_e-L_μ } symmetry, which is the most economical anomaly-free theory to potentially explain the peak by DM annihilation in nearby subhalo. We utilize the process χ χ → Z^' Z^' → l \\bar{l} l^' \\bar{l}^' , where χ , Z^' , l^{(' )} denote the scalar DM, the new gauge boson and l^{(' )} =e, μ , respectively, to generate the e^+e^- spectrum. By fitting the predicted spectrum to the experimental data, we obtain the favored DM mass range m_χ ˜eq 3060^{+80}_{-100} GeV and Δ m ≡ m_χ - m_{Z^' } ≲ 14 GeV at 68% Confidence Level (C.L.). Furthermore, we determine the parameter space of the model which can explain the peak and meanwhile satisfy the constraints from DM relic abundance, DM direct detection and the collider bounds. We conclude that the model we consider can account for the peak, although there exists a tension with the constraints from the LEP-II bound on m_{Z^' } arising from the cross section measurement of e^+e^- → Z^' *} → e^+ e^-.

76 FR 20835 - Amendment of VOR Federal Airways V-1, V-7, V-11 and V-20; Kona, HI

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-14

...; Airspace Docket No. 10-AWP-20] Amendment of VOR Federal Airways V-1, V-7, V-11 and V-20; Kona, HI AGENCY..., HI; V-1, V-7, V-11 and V-20. The FAA is taking this action due to procedural changes requiring..., (76 FR 13082), amends VOR Federal Airways V-1, V-7 V-11 and V-20; Kona, HI. These VHF Omnidirectional...

Comparison of Oral Reading Errors between Contextual Sentences and Random Words among Schoolchildren

ERIC Educational Resources Information Center

Khalid, Nursyairah Mohd; Buari, Noor Halilah; Chen, Ai-Hong

2017-01-01

This paper compares the oral reading errors between the contextual sentences and random words among schoolchildren. Two sets of reading materials were developed to test the oral reading errors in 30 schoolchildren (10.00±1.44 years). Set A was comprised contextual sentences while Set B encompassed random words. The schoolchildren were asked to…

The transfer of Crel contextual control (same, opposite, less than, more than) through equivalence relations.

PubMed

Perez, William F; Kovac, Roberta; Nico, Yara C; Caro, Daniel M; Fidalgo, Adriana P; Linares, Ila; de Almeida, João Henrique; de Rose, Júlio C

2017-11-01

According to Relational Frame Theory (RFT) C rel denotes a contextual stimulus that controls a particular type of relational response (sameness, opposition, comparative, temporal, hierarchical etc.) in a given situation. Previous studies suggest that contextual functions may be indirectly acquired via transfer of function. The present study investigated the transfer of C rel contextual control through equivalence relations. Experiment 1 evaluated the transfer of C rel contextual functions for relational responses based on sameness and opposition. Experiment 2 extended these findings by evaluating transfer of function using comparative C rel stimuli. Both experiments followed a similar sequence of phases. First, abstract forms were established as C rel stimuli via multiple exemplar training (Phase 1). The contextual cues were then applied to establish arbitrary relations among nonsense words and to test derived relations (Phase 2). After that, equivalence relations involving the original C rel stimuli and other abstract forms were trained and tested (Phase 3). Transfer of function was evaluated by replacing the directly established C rel stimuli with their equivalent stimuli in the former experimental tasks (Phases 1 and 2). Results from both experiments suggest that C rel contextual control may be extended via equivalence relations, allowing other arbitrarily related stimuli to indirectly acquire C rel functions and regulate behavior by evoking appropriate relational responses in the presence of both previously known and novel stimuli. © 2017 Society for the Experimental Analysis of Behavior.

The Formation of Conservation-Based Behaviour of Mechanical Engineering Students through Contextual Learning Approach

ERIC Educational Resources Information Center

Sudarman; Djuniadi; Sutopo, Yeri

2017-01-01

This study was aimed to figure out: (1) the implementation of contextual learning approaches; (2) the learning outcome of conservation education using contextual approach on the internship program preparation class; (3) the conservation-based behaviour of the internship program participants; (4) the contribution of conservation education results…

The V1V2 EOS for Detonation Products

NASA Astrophysics Data System (ADS)

Partom, Yehuda

2010-10-01

Many equations of state (EOS) for detonation products have been proposed and used. Some of them are in analytical form and some in tabular form. The most popular is the Jones-Wilkins-Lee (JWL) EOS. One of the main parameters of a product's EOS is the so-called adiabatic gamma along its main isentrope (γs). For JWL EOSs γs(V) varies in a nonmonotonic way. Going down from the CJ point along the main isentrope, it first increases to create a hump, and then, as V goes to infinity, gamma decreases to perfect gas-like behavior with gamma around 1.3. But according to Davis [1], γs(V) should decrease monotonically with V. Accordingly, in this article we investigate the following: (1) Is the hump in γs(V) necessary? and (2) Is it possible to construct a product's EOS with a monotonic γs(V) that is consistent with experimental data? We find that (1) it is possible to construct a product's EOS without a hump in γs(V); and (2) without a hump in γs(V) there are not enough degrees of freedom to reproduce cylinder test data.

Contextual Information and Verifying Inferences from Conversations.

ERIC Educational Resources Information Center

Dubitsky, Tony

Research was conducted to investigate the effects of contextual information on the speed and accuracy with which two general classes of inferences were verified by readers. These types of inferences were based on information in conversations that were or were not topically ambiguous, depending upon the amount of available contextual information.…

Intertrial Temporal Contextual Cuing: Association across Successive Visual Search Trials Guides Spatial Attention

ERIC Educational Resources Information Center

Ono, Fuminori; Jiang, Yuhong; Kawahara, Jun-ichiro

2005-01-01

Contextual cuing refers to the facilitation of performance in visual search due to the repetition of the same displays. Whereas previous studies have focused on contextual cuing within single-search trials, this study tested whether 1 trial facilitates visual search of the next trial. Participants searched for a T among Ls. In the training phase,…

Entering into dialogue about the mathematical value of contextual mathematising tasks

NASA Astrophysics Data System (ADS)

Yoon, Caroline; Chin, Sze Looi; Moala, John Griffith; Choy, Ban Heng

2018-03-01

Our project seeks to draw attention to the rich mathematical thinking that is generated when students work on contextual mathematising tasks. We use a design-based research approach to create ways of reporting that raise the visibility of this rich mathematical thinking while retaining and respecting its complexity. These reports will be aimed for three classroom stakeholders: (1) students, who wish to reflect on and enhance their mathematical learning; (2) teachers, who wish to integrate contextual mathematising tasks into their teaching practice and (3) researchers, who seek rich tasks for generating observable instances of mathematical thinking and learning. We anticipate that these reports and the underlying theoretical framework for creating them will contribute to greater awareness of and appreciation for the mathematical value of contextual mathematising tasks in learning, teaching and research.

Cat odor causes long-lasting contextual fear conditioning and increased pituitary-adrenal activation, without modifying anxiety.

PubMed

Muñoz-Abellán, Cristina; Daviu, Nuria; Rabasa, Cristina; Nadal, Roser; Armario, Antonio

2009-10-01

A single exposure to a cat or cat odors has been reported by some groups to induce contextual and auditory fear conditioning and long-lasting changes in anxiety-like behaviour, but there is no evidence for parallel changes in biological stress markers. In the present study we demonstrated in male rats that exposure to a novel environment containing a cloth impregnated with cat fur odor resulted in avoidance of the odor, lower levels of activity and higher pituitary-adrenal (PA) response as compared to those exposed to the novel environment containing a clean cloth, suggesting increased levels of stress in the former animals. When re-exposed 9 days later to the same environment with a clean cloth, previously cat fur exposed rats again showed avoidance of the cloth area and lower levels of activity, suggesting development of contextual fear conditioning, which again was associated with a higher PA activation. In contrast, unaltered both anxiety-like behaviour and PA responsiveness to an elevated plus-maze were found 7 days after cat odor exposure. It is concluded that: (i) PA activation is able to reflect both the stressful properties of cat fur odor and odor-induced contextual fear conditioning; (ii) development of cat odor-induced contextual fear conditioning is independent of the induction of long-lasting changes in anxiety-like behaviour; and (iii) greater PA activation during exposure to the odor context is not explained by non-specific sensitization of the PA axis caused by previous exposure to cat fur odor.

TNO and RUN at the TREC 2012 Contextual Suggestion Track: Recommending Personalized Touristic Sights Using Google Places

DTIC Science & Technology

2012-11-01

TNO and RUN at the TREC 2012 Contextual Suggestion Track: Recommending personalized touristic sights using Google Places Maya Sappelli∗1, Suzan...quite conservative . Figure 1: Accuracies on the ratings and contextual fits (0, 1 and 2) A more detailed look on the distribution of positive, neutral

The role of attention in figure-ground segregation in areas V1 and V4 of the visual cortex.

PubMed

Poort, Jasper; Raudies, Florian; Wannig, Aurel; Lamme, Victor A F; Neumann, Heiko; Roelfsema, Pieter R

2012-07-12

Our visual system segments images into objects and background. Figure-ground segregation relies on the detection of feature discontinuities that signal boundaries between the figures and the background and on a complementary region-filling process that groups together image regions with similar features. The neuronal mechanisms for these processes are not well understood and it is unknown how they depend on visual attention. We measured neuronal activity in V1 and V4 in a task where monkeys either made an eye movement to texture-defined figures or ignored them. V1 activity predicted the timing and the direction of the saccade if the figures were task relevant. We found that boundary detection is an early process that depends little on attention, whereas region filling occurs later and is facilitated by visual attention, which acts in an object-based manner. Our findings are explained by a model with local, bottom-up computations for boundary detection and feedback processing for region filling. Copyright © 2012 Elsevier Inc. All rights reserved.

Inhaled Lavandula angustifolia essential oil inhibits consolidation of contextual- but not tone-fear conditioning in rats.

PubMed

Coelho, Laura Segismundo; Correa-Netto, Nelson Francisco; Masukawa, Marcia Yuriko; Lima, Ariadiny Caetano; Maluf, Samia; Linardi, Alessandra; Santos-Junior, Jair Guilherme

2018-04-06

Although the current treatment for anxiety is effective, it promotes a number of adverse reactions and medical interactions. Inhaled essential oils have a prominent action on the central nervous system, with minimal systemic effects, primarily because of reduced systemic bioavailability. The effects of drugs on the consolidation of fear conditioning reflects its clinical efficacy in preventing a vicious cycle of anticipatory anxiety leading to fearful cognition and anxiety symptoms. In this study, we investigated the effects of inhaled Lavandula angustifolia essential oil on the consolidation of aversive memories and its influence on c-Fos expression. Adult male Wistar rats were subjected to a fear conditioning protocol. Immediately after the training session, the rats were exposed to vaporized water or essential oil (1%, 2.5% and 5% solutions) for 4h. The next day, the rats underwent contextual- or tone-fear tests and 90min after the test they were euthanized and their brains processed for c-Fos immunohistochemistry. In the contextual-fear test, essential oil at 2.5% and 5% (but not 1%) reduced the freezing response and its respective c-Fos expression in the ventral hippocampus and amygdala. In the tone-fear test, essential oil did not reduce the freezing response during tone presentation. However, rats that inhaled essential oil at 2.5% and 5% (but not 1%) showed decreased freezing in the three minutes after tone presentation, as well as reduced c-Fos expression in the prefrontal cortex and amygdala. These results show that the inhalation of L. angustifolia essential oil inhibited the consolidation of contextual- but not tone-fear conditioning and had an anxiolytic effect in a conditioned animal model of anxiety. Copyright © 2018 Elsevier B.V. All rights reserved.

X-ray Photoelectron Spectroscopy study of CaV1-xMoxO3-δ

NASA Astrophysics Data System (ADS)

Belyakov, S. A.; Kuznetsov, M. V.; Shkerin, S. N.

2018-06-01

An investigation was carried out on perovskite-based derivatives of CaV1-xMoxO3-δ using X-ray Photoelectron Spectroscopy (XPS). According to the XRD pattern, the area of homogeneity covers the region from x = 0 to x = 0.6. Wide XPS-peaks of Ca, V, Mo and O are observed, signalling that elements are presented in multiple states. A model for explaining the large chemical shifts of XPS peaks due to different charging effects on different parts of the sample surface is proposed.

Validating Domains of Patient Contextual Factors Essential to Preventing Contextual Errors: A Qualitative Study Conducted at Chicago Area Veterans Health Administration Sites.

PubMed

Binns-Calvey, Amy E; Malhiot, Alex; Kostovich, Carol T; LaVela, Sherri L; Stroupe, Kevin; Gerber, Ben S; Burkhart, Lisa; Weiner, Saul J; Weaver, Frances M

2017-09-01

"Patient context" indicates patient circumstances and characteristics or states that are essential to address when planning patient care. Specific patient "contextual factors," if overlooked, result in an inappropriate plan of care, a medical error termed a "contextual error." The myriad contextual factors that constitute patient context have been grouped into broad domains to create a taxonomy of challenges to consider when planning care. This study sought to validate a previously identified list of contextual domains. This qualitative study used directed content analysis. In 2014, 19 Department of Veterans Affairs (VA) providers (84% female) and 49 patients (86% male) from two VA medical centers and four outpatient clinics in the Chicago area participated in semistructured interviews and focus groups. Topics included patient-specific, community, and resource-related factors that affect patients' abilities to manage their care. Transcripts were analyzed with a previously identified list of contextual domains as a framework. Analysis of responses revealed that patients and providers identified the same 10 domains previously published, plus 3 additional ones. Based on comments made by patients and providers, the authors created a revised list of 12 domains from themes that emerged. Six pertain to patient circumstances such as access to care and financial situation, and 6 to patient characteristics/states including skills, abilities, and knowledge. Contextual factors in patients' lives may be essential to address for effective care planning. The rubric developed can serve as a "contextual differential" for clinicians to consider when addressing challenges patients face when planning their care.

Contextuality in canonical systems of random variables

NASA Astrophysics Data System (ADS)

Dzhafarov, Ehtibar N.; Cervantes, Víctor H.; Kujala, Janne V.

2017-10-01

Random variables representing measurements, broadly understood to include any responses to any inputs, form a system in which each of them is uniquely identified by its content (that which it measures) and its context (the conditions under which it is recorded). Two random variables are jointly distributed if and only if they share a context. In a canonical representation of a system, all random variables are binary, and every content-sharing pair of random variables has a unique maximal coupling (the joint distribution imposed on them so that they coincide with maximal possible probability). The system is contextual if these maximal couplings are incompatible with the joint distributions of the context-sharing random variables. We propose to represent any system of measurements in a canonical form and to consider the system contextual if and only if its canonical representation is contextual. As an illustration, we establish a criterion for contextuality of the canonical system consisting of all dichotomizations of a single pair of content-sharing categorical random variables. This article is part of the themed issue `Second quantum revolution: foundational questions'.

Contextual remapping in visual search after predictable target-location changes.

PubMed

Conci, Markus; Sun, Luning; Müller, Hermann J

2011-07-01

Invariant spatial context can facilitate visual search. For instance, detection of a target is faster if it is presented within a repeatedly encountered, as compared to a novel, layout of nontargets, demonstrating a role of contextual learning for attentional guidance ('contextual cueing'). Here, we investigated how context-based learning adapts to target location (and identity) changes. Three experiments were performed in which, in an initial learning phase, observers learned to associate a given context with a given target location. A subsequent test phase then introduced identity and/or location changes to the target. The results showed that contextual cueing could not compensate for target changes that were not 'predictable' (i.e. learnable). However, for predictable changes, contextual cueing remained effective even immediately after the change. These findings demonstrate that contextual cueing is adaptive to predictable target location changes. Under these conditions, learned contextual associations can be effectively 'remapped' to accommodate new task requirements.

Contextual Learning Issues.

ERIC Educational Resources Information Center

1999

This document contains four symposium papers on contextual learning issues. "Learning to Learn Strategies of Successful Real Estate Professionals: Implications for Learning in the Workplace" (Margot B. Weinstein) describes a multicase study in which a model called the Individual Learning System was used to identify the strategies and…

Contextual cueing in multiconjunction visual search is dependent on color- and configuration-based intertrial contingencies.

PubMed

Geyer, Thomas; Shi, Zhuanghua; Müller, Hermann J

2010-06-01

Three experiments examined memory-based guidance of visual search using a modified version of the contextual-cueing paradigm (Jiang & Chun, 2001). The target, if present, was a conjunction of color and orientation, with target (and distractor) features randomly varying across trials (multiconjunction search). Under these conditions, reaction times (RTs) were faster when all items in the display appeared at predictive ("old") relative to nonpredictive ("new") locations. However, this RT benefit was smaller compared to when only one set of items, namely that sharing the target's color (but not that in the alternative color) appeared in predictive arrangement. In all conditions, contextual cueing was reliable on both target-present and -absent trials and enhanced if a predictive display was preceded by a predictive (though differently arranged) display, rather than a nonpredictive display. These results suggest that (1) contextual cueing is confined to color subsets of items, that (2) retrieving contextual associations for one color subset of items can be impeded by associations formed within the alternative subset ("contextual interference"), and (3) that contextual cueing is modulated by intertrial priming.

Task-relevant information is prioritized in spatiotemporal contextual cueing.

PubMed

Higuchi, Yoko; Ueda, Yoshiyuki; Ogawa, Hirokazu; Saiki, Jun

2016-11-01

Implicit learning of visual contexts facilitates search performance-a phenomenon known as contextual cueing; however, little is known about contextual cueing under situations in which multidimensional regularities exist simultaneously. In everyday vision, different information, such as object identity and location, appears simultaneously and interacts with each other. We tested the hypothesis that, in contextual cueing, when multiple regularities are present, the regularities that are most relevant to our behavioral goals would be prioritized. Previous studies of contextual cueing have commonly used the visual search paradigm. However, this paradigm is not suitable for directing participants' attention to a particular regularity. Therefore, we developed a new paradigm, the "spatiotemporal contextual cueing paradigm," and manipulated task-relevant and task-irrelevant regularities. In four experiments, we demonstrated that task-relevant regularities were more responsible for search facilitation than task-irrelevant regularities. This finding suggests our visual behavior is focused on regularities that are relevant to our current goal.

The problem of contextuality and the impossibility of experimental metaphysics thereof

NASA Astrophysics Data System (ADS)

Hermens, Ronnie

Recently a new impulse has been given to the experimental investigation of contextuality. In this paper we show that for a widely used definition of contextuality there can be no decisive experiment on the existence of contextuality. To this end, we give a clear presentation of the hidden variable models due to Meyer, Kent and Clifton (MKC), which would supposedly nullify the Kochen-Specker theorem. Although we disagree with this last statement, the models do play a significant role in the discussion on the meaning of contextuality. In fact, we introduce a specific MKC-model of which we show that it is non-contextual and completely in agreement with quantum mechanical predictions. We also investigate the possibility of other definitions of non-contextuality-with an emphasis on operational definitions-and argue that any useful definition relies on the specification of a theoretical framework. It is therefore concluded that no experimental test can yield any conclusions about contextuality on a metaphysical level.

Contextual and Non-Contextual Knowledge in Emergent Literacy Development: A Comparison between Children from Low Ses and Middle Ses Communities

ERIC Educational Resources Information Center

Korat, O.

2005-01-01

This research had three aims: first, to examine the relationship between two components of emergent literacy: contextual (environmental print, print functions, identifying literacy activities) and non-contextual knowledge (e.g., letters' names, phonemic awareness, concept of print, etc.); second, to explore the relationship between children's…

Early Adolescents' Emotional Well-Being in the Classroom: The Role of Personal and Contextual Assets.

PubMed

Oberle, Eva

2018-02-01

The objective was to predict early adolescents' emotional well-being from personal and contextual assets in the classroom. Emotional well-being is a key indicator of health. Aligned with the positive youth development (PYD) framework, a supportive classroom environment and positive relationships with teachers and peers were contextual assets in the present study; positive self-concept was a personal asset. The sample was 406 grade 4 to 7 public elementary school students from diverse backgrounds (mean = 11.27 years; SD = 0.89; 50% female). Data were self-, teacher-, and peer-reported. Structural equation modeling (SEM) analyses were used to evaluate model fit and identify significant pathways. SEM indicated a good model fit. Overall, 68% of variability in early adolescents' emotional well-being was explained. Positive self-concept directly predicted emotional well-being. Supportive classroom environment predicted emotional well-being directly and indirectly through increases in positive social relationships and self-concept. Positive social relationships predicted well-being only indirectly through positive self-concept. Contextual and personal assets are central for early adolescents' emotional well-being. The interrelation among assets needs to be considered when understanding, and ultimately promoting students' emotional well-being. The present findings extend previous research and inform school-based intervention and prevention programming and teacher professional development. © 2018, American School Health Association.

Contextual advertisement placement in printed media

NASA Astrophysics Data System (ADS)

Liu, Sam; Joshi, Parag

2010-02-01

Advertisements today provide the necessary revenue model supporting the WWW ecosystem. Targeted or contextual ad insertion plays an important role in optimizing the financial return of this model. Nearly all the current ads that appear on web sites are geared for display purposes such as banner and "pay-per-click". Little attention, however, is focused on deriving additional ad revenues when the content is repurposed for alternative mean of presentation, e.g. being printed. Although more and more content is moving to the Web, there are still many occasions where printed output of web content is desirable, such as maps and articles; thus printed ad insertion can potentially be lucrative. In this paper, we describe a contextual ad insertion network aimed to realize new revenue for print service providers for web printing. We introduce a cloud print service that enables contextual ads insertion, with respect to the main web page content, when a printout of the page is requested. To encourage service utilization, it would provide higher quality printouts than what is possible from current browser print drivers, which generally produce poor outputs, e.g. ill formatted pages. At this juncture we will limit the scope to only article-related web pages although the concept can be extended to arbitrary web pages. The key components of this system include (1) the extraction of article from web pages, (2) the extraction of semantics from article, (3) querying the ad database for matching advertisement or coupon, and (4) joint content and ad layout for print outputs.

Factor analysis of the contextual fine motor questionnaire in children.

PubMed

Lin, Chin-Kai; Meng, Ling-Fu; Yu, Ya-Wen; Chen, Che-Kuo; Li, Kuan-Hua

2014-02-01

Most studies treat fine motor as one subscale in a developmental test, hence, further factor analysis of fine motor has not been conducted. In fact, fine motor has been treated as a multi-dimensional domain from both clinical and theoretical perspectives, and therefore to know its factors would be valuable. The aim of this study is to analyze the internal consistency and factor validity of the Contextual Fine Motor Questionnaire (CFMQ). Based on the ecological observation and literature, the Contextual Fine Motor Questionnaire (CFMQ) was developed and includes 5 subscales: Pen Control, Tool Use During Handicraft Activities, the Use of Dining Utensils, Connecting and Separating during Dressing and Undressing, and Opening Containers. The main purpose of this study is to establish the factorial validity of the CFMQ through conducting this factor analysis study. Among 1208 questionnaires, 904 were successfully completed. Data from the children's CFMQ submitted by primary care providers was analyzed, including 485 females (53.6%) and 419 males (46.4%) from grades 1 to 5, ranging in age from 82 to 167 months (M=113.9, SD=16.3). Cronbach's alpha was used to measure internal consistency and explorative factor analysis was applied to test the five factor structures within the CFMQ. Results showed that Cronbach's alpha coefficient of the CFMQ for 5 subscales ranged from .77 to .92 and all item-total correlations with corresponding subscales were larger than .4 except one item. The factor loading of almost all items classified to their factor was larger than .5 except 3 items. There were five factors, explaining a total of 62.59% variance for the CFMQ. In conclusion, the remaining 24 items in the 5 subscales of the CFMQ had appropriate internal consistency, test-retest reliability and construct validity. Copyright © 2013 Elsevier Ltd. All rights reserved.

Acute nicotine disrupts consolidation of contextual fear extinction and alters long-term memory-associated hippocampal kinase activity.

PubMed

Kutlu, Munir Gunes; Garrett, Brendan; Gadiwalla, Sana; Tumolo, Jessica M; Gould, Thomas J

2017-11-01

Previous research has shown that acute nicotine, an agonist of nAChRs, impaired fear extinction. However, the effects of acute nicotine on consolidation of contextual fear extinction memories and associated cell signaling cascades are unknown. Therefore, we examined the effects of acute nicotine injections before (pre-extinction) and after (post-extinction) contextual fear extinction on behavior and the phosphorylation of dorsal and ventral hippocampal ERK1/2 and JNK1 and protein levels on the 1st and 3rd day of extinction. Our results showed that acute nicotine administered prior to extinction sessions downregulated the phosphorylated forms of ERK1/2 in the ventral hippocampus, but not dorsal hippocampus, and JNK1 in both dorsal and ventral hippocampus on the 3rd extinction day. These effects were absent on the 1st day of extinction. We also showed that acute nicotine administered immediately and 30 min, but not 6 h, following extinction impaired contextual fear extinction suggesting that acute nicotine disrupts consolidation of contextual fear extinction memories. Finally, acute nicotine injections immediately after extinction sessions upregulated the phosphorylated forms of ERK1/2 in the ventral hippocampus, but did not affect JNK1. These results show that acute nicotine impairs contextual fear extinction potentially by altering molecular processes responsible for the consolidation of extinction memories. Copyright © 2017 Elsevier Inc. All rights reserved.

Kinetics of the immune response to the (F1+V) vaccine in models of bubonic and pneumonic plague.

PubMed

Williamson, E D; Stagg, A J; Eley, S M; Taylor, R; Green, M; Jones, S M; Titball, R W

2007-01-22

Protection against aerosol challenge with > 300 MLD of Yersinia pestis was observed 7 days after a single immunisation of mice with the F1+V vaccine. At day 60, mice were protected against injected challenge (10(7)MLD) in a vaccine dose-related manner. Recall responses to rV in splenocytes ex vivo at day 98 correlated significantly (p<0.001) with the immunising dose-level of V antigen; no memory response or anti-V serum IgG was detected in killed whole cell vaccine (KWCV) recipients. This may explain the susceptibility of KWCV recipients to aerosol challenge and the enhanced protection conferred by the F1+V sub-unit vaccine, particularly since the anti-F1 responses induced by either vaccine were similarly IgG1-polarised.

Implicit sequence learning and contextual cueing do not compete for central cognitive resources.

PubMed

Jiménez, Luis; Vázquez, Gustavo A

2011-02-01

Sequence learning and contextual cueing explore different forms of implicit learning, arising from practice with a structured serial task, or with a search task with informative contexts. We assess whether these two learning effects arise simultaneously when both remain implicit. Experiments 1 and 2 confirm that a cueing effect can be observed under a continuous setting and that there is no interference between contextual cueing and sequence learning. Experiments 3a and 3b tested whether an interference arises specifically when the sequence becomes explicit. Results show that the expression of contextual cueing disappeared in those conditions but that context information is still acquired, and it affects performance when the sequence is removed. The results are discussed in relation to the current debates about the automaticity of implicit learning, and about the role of attention in the acquisition and expression of contextual cueing. (c) 2010 APA, all rights reserved.

Understanding contextual influences of community reintegration among injured servicemembers.

PubMed

Hawkins, Brent L; McGuire, Francis A; Linder, Sandra M; Britt, Thomas W

2015-01-01

As part of a larger mixed-methods research project investigating the influence of contextual factors on community reintegration (CR), this qualitative study sought to understand the subjective experiences of injured servicemembers and their perception of how contextual factors influenced their CR. More specifically, this article addresses how the influences of contextual factors differ between injured servicemembers with different levels of CR. Using a phenomenological framework, semistructured interviews were conducted with nine injured, community-dwelling servicemembers with low, moderate, and high levels of CR (three per category). Participants provided in-depth descriptions of the contextual barriers and facilitators of CR. Thematic analysis indicated the importance of social support and personal factors (e.g., self-efficacy, personal motivation) as the primary means for being reintegrated into their homes and communities. Other themes indicated factors that had an indirect but important influence on CR, including adapted sports, recreation, and other social programs; rehabilitation programs and therapists; school, work, and volunteering; and organizations and policies in developing social supports and personal factors. Comparisons between servicemembers indicated participants with low CR described many more contextual barriers and far fewer contextual facilitators to reintegration than those with high CR. Those with moderate CR were unique in that they described many facilitators and barriers to reintegration.

Contextual Learning Issues.

ERIC Educational Resources Information Center

1996

This document consists of four papers presented at a symposium on contextual learning issues moderated by John Henschke at the 1996 conference of the Academy of Human Resource Development (AHRD). "Self-Directed Learning in Organizations: An Analysis of Policies and Practices of Seven Resource Companies in Western Canada" (H. K. Morris…

Object-based implicit learning in visual search: perceptual segmentation constrains contextual cueing.

PubMed

Conci, Markus; Müller, Hermann J; von Mühlenen, Adrian

2013-07-09

In visual search, detection of a target is faster when it is presented within a spatial layout of repeatedly encountered nontarget items, indicating that contextual invariances can guide selective attention (contextual cueing; Chun & Jiang, 1998). However, perceptual regularities may interfere with contextual learning; for instance, no contextual facilitation occurs when four nontargets form a square-shaped grouping, even though the square location predicts the target location (Conci & von Mühlenen, 2009). Here, we further investigated potential causes for this interference-effect: We show that contextual cueing can reliably occur for targets located within the region of a segmented object, but not for targets presented outside of the object's boundaries. Four experiments demonstrate an object-based facilitation in contextual cueing, with a modulation of context-based learning by relatively subtle grouping cues including closure, symmetry, and spatial regularity. Moreover, the lack of contextual cueing for targets located outside the segmented region was due to an absence of (latent) learning of contextual layouts, rather than due to an attentional bias towards the grouped region. Taken together, these results indicate that perceptual segmentation provides a basic structure within which contextual scene regularities are acquired. This in turn argues that contextual learning is constrained by object-based selection.

Employment outcome for people with schizophrenia in rural v. urban China: population-based study

PubMed Central

Yang, Lawrence H.; Phillips, Michael R.; Li, Xianyun; Yu, Gary; Zhang, Jingxuan; Shi, Qichang; Song, Zhiqiang; Ding, Zhijie; Pang, Shutao; Susser, Ezra

2013-01-01

Background Although outcomes among people with schizophrenia differ by social context, this has rarely been examined across rural v. urban settings. For individuals with schizophrenia, employment is widely recognised as a critical ingredient of social integration. Aims To compare employment for people with schizophrenia in rural v. urban settings in China. Method In a large community-based study in four provinces representing 12% of China’s population, we identified 393 people with schizophrenia (112 never treated). We used adjusted Poisson regression models to compare employment for those living in rural (n = 297) v. urban (n = 96) settings. Results Although rural and urban residents had similar impairments due to symptoms, rural residents were three times more likely to be employed (adjusted relative risk 3.27, 95% CI 2.11–5.07, P<0.001). Conclusions People with schizophrenia have greater opportunities to use their capacities for productive work in rural than urban settings in China. Contextual mechanisms that may explain this result offer a useful focus for future research. PMID:23258768

Retrieving autobiographical memories: How different retrieval strategies associated with different cues explain reaction time differences.

PubMed

Uzer, Tugba

2016-02-01

Previous research has shown that memories cued by concrete concepts, such as objects, are retrieved faster than those cued by more abstract concepts, such as emotions. This effect has been explained by the fact that more memories are directly retrieved from object versus emotion cues. In the present study, we tested whether RT differences between memories cued by emotion versus object terms occur not only because object cues elicit direct retrieval of more memories (Uzer, Lee, & Brown, 2012), but also because of differences in memory generation in response to emotions versus objects. One hundred university students retrieved memories in response to basic-level (e.g. orange), superordinate-level (e.g. plant), and emotion (e.g. surprised) cues. Retrieval speed was measured and participants reported whether memories were directly retrieved or generated on each trial. Results showed that memories were retrieved faster in response to basic-level versus superordinate-level and emotion cues because a) basic-level cues elicited more directly retrieved memories, and b) generating memories was more difficult when cues were abstract versus concrete. These results suggest that generative retrieval is a cue generation process in which additional cues that provide contextual information including the target event are produced. Memories are retrieved more slowly in response to emotion cues in part because emotion labels are less effective cues of appropriate contextual information. This particular finding is inconsistent with the idea that emotion is a primary organizational unit for autobiographical memories. In contrast, the difficulty of emotional memory generation implies that emotions represent low-level event information in the organization of autobiographical memory. Copyright © 2016 Elsevier B.V. All rights reserved.

The portion size effect on food intake is robust to contextual size information.

PubMed

Reily, Natalie M; Vartanian, Lenny R

2016-10-01

Larger portion sizes have consistently been shown to lead to greater food intake. However, studies of the portion size effect typically provided participants with a single portion of food at a time without any objective information about the size of the portion, and hence failed to consider the potential significance of contextual size information. In order to investigate whether contextual size information moderates the portion size effect, participants were served small or large portions of pasta for lunch in the presence or absence of contextual size information. Study 1 found that the portion size effect on food intake was robust to contextual size information. Study 2 replicated this finding in an online paradigm, showing that contextual size information also had no influence on prospective intake, even when participants chose the portion size they preferred. Both studies also showed that participants' perceptions of how much was appropriate to eat mediated the effect of portion size on intake. A practical implication of our findings is that modifying consumption norms may be an effective way to promote healthier consumer food decisions. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Individual and contextual determinants of the prevalence of untreated caries in Brazil].

PubMed

Frias, Antônio Carlos; Antunes, José Leopoldo Ferreira; Junqueira, Simone Rennó; Narvai, Paulo Capel

2007-10-01

To describe the prevalence of untreated caries among adolescents in Brazil and to analyze the association between caries and individual and contextual factors in the municipalities where these adolescents live. A Ministry of Health database (projeto SB-Brasil) provided health records on 16 833 adolescents from 15-19 years of age. The study variable used was the presence of at least one permanent tooth having been lost to caries. The individual variables considered were: sex, ethnic group, living in an urban versus a rural area, and being a student or not. Contextual variables related to the municipality were: municipal human development index (MHDI), proportion of households connected to the water system, and water fluoridation for 5 years or more. Multilevel logistic regression analysis was carried out to adjust the outcome to the individual and contextual variables. Individual determinants related to a higher probability of untreated caries were: the ethnic group described as "black or brown," (adjusted odds ratio, OR(adjust) = 1.79; 1.68 to 1.92); and living in a rural area (OR(adjust) = 1.31; 1.19 to 1.45). Being a student was identified as a protective factor (OR(adjust) = 0.67; 0.62 to 0.73). Secondary variables identified as contextual determinants of caries were MHDI (adjusted coefficient beta = -0.213), water fluoridation (beta = -0.201), and households connected to the water system (beta = -0.197). The results show inequalities in the distribution of health services in the various Brazilian regions, and suggest that inequalities may also be present in the effectiveness of the services provided. Policies to increase access to fluoride-treated water and school enrollment may contribute to preventing caries in adolescents.

Configural learning in contextual cuing of visual search.

PubMed

Beesley, Tom; Vadillo, Miguel A; Pearson, Daniel; Shanks, David R

2016-08-01

Two experiments were conducted to explore the role of configural representations in contextual cuing of visual search. Repeating patterns of distractors (contexts) were trained incidentally as predictive of the target location. Training participants with repeating contexts of consistent configurations led to stronger contextual cuing than when participants were trained with contexts of inconsistent configurations. Computational simulations with an elemental associative learning model of contextual cuing demonstrated that purely elemental representations could not account for the results. However, a configural model of associative learning was able to simulate the ordinal pattern of data. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Quantum key distribution protocol based on contextuality monogamy

NASA Astrophysics Data System (ADS)

Singh, Jaskaran; Bharti, Kishor; Arvind

2017-06-01

The security of quantum key distribution (QKD) protocols hinges upon features of physical systems that are uniquely quantum in nature. We explore the role of quantumness, as qualified by quantum contextuality, in a QKD scheme. A QKD protocol based on the Klyachko-Can-Binicioğlu-Shumovsky (KCBS) contextuality scenario using a three-level quantum system is presented. We explicitly show the unconditional security of the protocol by a generalized contextuality monogamy relationship based on the no-disturbance principle. This protocol provides a new framework for QKD which has conceptual and practical advantages over other protocols.

Contextual control over task-set retrieval.

PubMed

Crump, Matthew J C; Logan, Gordon D

2010-11-01

Contextual cues signaling task likelihood or the likelihood of task repetition are known to modulate the size of switch costs. We follow up on the finding by Leboe, Wong, Crump, and Stobbe (2008) that location cues predictive of the proportion of switch or repeat trials modulate switch costs. Their design employed one cue per task, whereas our experiment employed two cues per task, which allowed separate assessment of modulations to the cue-repetition benefit, a measure of lower level cue-encoding processes, and to the task-alternation cost, a measure of higher level processes representing task-set information. We demonstrate that location information predictive of switch proportion modulates performance at the level of task-set representations. Furthermore, we demonstrate that contextual control occurs even when subjects are unaware of the associations between context and switch likelihood. We discuss the notion that contextual information provides rapid, unconscious control over the extent to which prior task-set representations are retrieved in the service of guiding online performance.

Hippocampal Regulation of Contextual Cue-Induced Reinstatement of Cocaine-Seeking Behavior

PubMed Central

Atkins, Alison L.; Mashhoon, Yasmin; Kantak, Kathleen M.

2008-01-01

Associations between cocaine and cues facilitate development and maintenance of addiction. We hypothesized that the ventral hippocampus is important for acquisition of these associations. Rats were trained to self-administer cocaine, with or without pre-exposure to distinct sets of cocaine- and saline-paired contextual cues. Next, rats were conditioned for 3 days with the distinct sets of contextual cues paired with cocaine and saline along with distinct discrete cues. Vehicle or lidocaine was infused into the ventral hippocampus prior to conditioning sessions. Following extinction, reinstatement of cocaine-seeking behavior was examined following exposure to contextual cues, discrete cues, or their combination. Inactivation of the ventral hippocampus during conditioning blocked acquisition of the association between cocaine and cocaine-paired contextual cues in that only lidocaine-treated rats with short-term cue exposure failed to reinstate responding in the presence of cocaine-paired contextual cues. Lidocaine also prevented rats in both cue exposure groups from discriminating between cocaine-and saline-paired contextual cues during reinstatement tests. Reinstatement induced by cocaine-paired discrete cues or by contextual and discrete cues together was not impaired for either cue exposure condition. The hippocampus is important for acquisition of the association between cocaine and context and in maintaining discrimination between cocaine-relevant and -irrelevant contextual cues. PMID:18499239

The effect of contextual sound cues on visual fidelity perception.

PubMed

Rojas, David; Cowan, Brent; Kapralos, Bill; Collins, Karen; Dubrowski, Adam

2014-01-01

Previous work has shown that sound can affect the perception of visual fidelity. Here we build upon this previous work by examining the effect of contextual sound cues (i.e., sounds that are related to the visuals) on visual fidelity perception. Results suggest that contextual sound cues do influence visual fidelity perception and, more specifically, our perception of visual fidelity increases with contextual sound cues. These results have implications for designers of multimodal virtual worlds and serious games that, with the appropriate use of contextual sounds, can reduce visual rendering requirements without a corresponding decrease in the perception of visual fidelity.

Contextual diversity facilitates learning new words in the classroom.

PubMed

Rosa, Eva; Tapia, José Luis; Perea, Manuel

2017-01-01

In the field of word recognition and reading, it is commonly assumed that frequently repeated words create more accessible memory traces than infrequently repeated words, thus capturing the word-frequency effect. Nevertheless, recent research has shown that a seemingly related factor, contextual diversity (defined as the number of different contexts [e.g., films] in which a word appears), is a better predictor than word-frequency in word recognition and sentence reading experiments. Recent research has shown that contextual diversity plays an important role when learning new words in a laboratory setting with adult readers. In the current experiment, we directly manipulated contextual diversity in a very ecological scenario: at school, when Grade 3 children were learning words in the classroom. The new words appeared in different contexts/topics (high-contextual diversity) or only in one of them (low-contextual diversity). Results showed that words encountered in different contexts were learned and remembered more effectively than those presented in redundant contexts. We discuss the practical (educational [e.g., curriculum design]) and theoretical (models of word recognition) implications of these findings.

Contextual diversity facilitates learning new words in the classroom

PubMed Central

Tapia, José Luis; Perea, Manuel

2017-01-01

In the field of word recognition and reading, it is commonly assumed that frequently repeated words create more accessible memory traces than infrequently repeated words, thus capturing the word-frequency effect. Nevertheless, recent research has shown that a seemingly related factor, contextual diversity (defined as the number of different contexts [e.g., films] in which a word appears), is a better predictor than word-frequency in word recognition and sentence reading experiments. Recent research has shown that contextual diversity plays an important role when learning new words in a laboratory setting with adult readers. In the current experiment, we directly manipulated contextual diversity in a very ecological scenario: at school, when Grade 3 children were learning words in the classroom. The new words appeared in different contexts/topics (high-contextual diversity) or only in one of them (low-contextual diversity). Results showed that words encountered in different contexts were learned and remembered more effectively than those presented in redundant contexts. We discuss the practical (educational [e.g., curriculum design]) and theoretical (models of word recognition) implications of these findings. PMID:28586354

Context matters: the experience of 14 research teams in systematically reporting contextual factors important for practice change.

PubMed

Tomoaia-Cotisel, Andrada; Scammon, Debra L; Waitzman, Norman J; Cronholm, Peter F; Halladay, Jacqueline R; Driscoll, David L; Solberg, Leif I; Hsu, Clarissa; Tai-Seale, Ming; Hiratsuka, Vanessa; Shih, Sarah C; Fetters, Michael D; Wise, Christopher G; Alexander, Jeffrey A; Hauser, Diane; McMullen, Carmit K; Scholle, Sarah Hudson; Tirodkar, Manasi A; Schmidt, Laura; Donahue, Katrina E; Parchman, Michael L; Stange, Kurt C

2013-01-01

We aimed to advance the internal and external validity of research by sharing our empirical experience and recommendations for systematically reporting contextual factors. Fourteen teams conducting research on primary care practice transformation retrospectively considered contextual factors important to interpreting their findings (internal validity) and transporting or reinventing their findings in other settings/situations (external validity). Each team provided a table or list of important contextual factors and interpretive text included as appendices to the articles in this supplement. Team members identified the most important contextual factors for their studies. We grouped the findings thematically and developed recommendations for reporting context. The most important contextual factors sorted into 5 domains: (1) the practice setting, (2) the larger organization, (3) the external environment, (4) implementation pathway, and (5) the motivation for implementation. To understand context, investigators recommend (1) engaging diverse perspectives and data sources, (2) considering multiple levels, (3) evaluating history and evolution over time, (4) looking at formal and informal systems and culture, and (5) assessing the (often nonlinear) interactions between contextual factors and both the process and outcome of studies. We include a template with tabular and interpretive elements to help study teams engage research participants in reporting relevant context. These findings demonstrate the feasibility and potential utility of identifying and reporting contextual factors. Involving diverse stakeholders in assessing context at multiple stages of the research process, examining their association with outcomes, and consistently reporting critical contextual factors are important challenges for a field interested in improving the internal and external validity and impact of health care research.

Contextual effects and cancer outcomes in the United States: a systematic review of characteristics in multilevel analyses.

PubMed

Zahnd, Whitney E; McLafferty, Sara L

2017-11-01

There is increasing call for the utilization of multilevel modeling to explore the relationship between place-based contextual effects and cancer outcomes in the United States. To gain a better understanding of how contextual factors are being considered, we performed a systematic review. We reviewed studies published between January 1, 2002 and December 31, 2016 and assessed the following attributes: (1) contextual considerations such as geographic scale and contextual factors used; (2) methods used to quantify contextual factors; and (3) cancer type and outcomes. We searched PubMed, Scopus, and Web of Science and initially identified 1060 studies. One hundred twenty-two studies remained after exclusions. Most studies utilized a two-level structure; census tracts were the most commonly used geographic scale. Socioeconomic factors, health care access, racial/ethnic factors, and rural-urban status were the most common contextual factors addressed in multilevel models. Breast and colorectal cancers were the most common cancer types, and screening and staging were the most common outcomes assessed in these studies. Opportunities for future research include deriving contextual factors using more rigorous approaches, considering cross-classified structures and cross-level interactions, and using multilevel modeling to explore understudied cancers and outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

Children with Physical Disabilities at School and Home: Physical Activity and Contextual Characteristics.

PubMed

Li, Ru; Sit, Cindy Hui-Ping; Yu, Jane Jie; Sum, Raymond Kim-Wai; Wong, Stephen Heung-Sang; Cheng, Kenneth Chik-Chi; McKenzie, Thomas L

2017-06-25

The purpose of this study was to assess the physical activity (PA) of children with physical disabilities (PD) in school and home settings and to simultaneously examine selected contextual characteristics in relation to PA in those settings. Children with PD (N = 35; Mean age = 15.67 ± 4.30 years; 26 boys) were systematically observed using BEACHES (Behaviors of Eating and Activity for Children's Health: Evaluation System) at school (before school, recess, lunch break, after class) and at home (before dinner) during four normal school days. The children spent most of their time in all five settings being physically inactive, but had slightly more PA during recess and lunch break periods. Hierarchical multiple regression revealed that selected contextual characteristics explained 18.9-56.0% ( p < 0.01) of the variance predicting moderate-to-vigorous physical activity (MVPA) after controlling for demographic variables. Prompts to be active were positively associated with MVPA at school and the presence of fathers and fathers being motivators at home. This study highlights how little PA that children with PD receive and identifies the importance of the provision of prompts for PA at both school and home with this special population.

Contextual Text Mining

ERIC Educational Resources Information Center

Mei, Qiaozhu

2009-01-01

With the dramatic growth of text information, there is an increasing need for powerful text mining systems that can automatically discover useful knowledge from text. Text is generally associated with all kinds of contextual information. Those contexts can be explicit, such as the time and the location where a blog article is written, and the…

Contextualized Instruction: Teaching Relevant Behaviors in Relevant Contexts.

ERIC Educational Resources Information Center

Reboy, Lisa M.; Semb, George B.

In contextualized instruction, the critical features of a context are considered important for the acquisition and transfer of a skill. Examples of contextualized instruction programs are Functional Context Education (FCE) and Anchored Instruction (AI). FCE involves the teaching of reading and mathematics skills in contexts that are relevant to…

Collinear integration affects visual search at V1.

PubMed

Chow, Hiu Mei; Jingling, Li; Tseng, Chia-huei

2013-08-29

Perceptual grouping plays an indispensable role in figure-ground segregation and attention distribution. For example, a column pops out if it contains element bars orthogonal to uniformly oriented element bars. Jingling and Tseng (2013) have reported that contextual grouping in a column matters to visual search behavior: When a column is grouped into a collinear (snakelike) structure, a target positioned on it became harder to detect than on other noncollinear (ladderlike) columns. How and where perceptual grouping interferes with selective attention is still largely unknown. This article contributes to this little-studied area by asking whether collinear contour integration interacts with visual search before or after binocular fusion. We first identified that the previously mentioned search impairment occurs with a distractor of five or nine elements but not one element in a 9 × 9 search display. To pinpoint the site of this effect, we presented the search display with a short collinear bar (one element) to one eye and the extending collinear bars to the other eye, such that when properly fused, the combined binocular collinear length (nine elements) exceeded the critical length. No collinear search impairment was observed, implying that collinear information before binocular fusion shaped participants' search behavior, although contour extension from the other eye after binocular fusion enhanced the effect of collinearity on attention. Our results suggest that attention interacts with perceptual grouping as early as V1.

Self-determined motivation in sport predicts anti-doping motivation and intention: a perspective from the trans-contextual model.

PubMed

Chan, D K C; Dimmock, J A; Donovan, R J; Hardcastle, S; Lentillon-Kaestner, V; Hagger, M S

2015-05-01

Motivation in sport has been frequently identified as a key factor of young athletes' intention of doping in sport, but there has not been any attempt in scrutinizing the motivational mechanism involved. The present study applied the trans-contextual model of motivation to explain the relationship between motivation in a sport context and motivation and the social-cognitive factors (attitude, subjective norm, perceived behavioral control, and intention) from the theory of planned behavior (TPB) in an anti-doping context. A cross-sectional survey was conducted. Questionnaire data was collected from 410 elite and sub-elite young athletes in Australia (Mean age [17.7±3.9 yr], 55.4% male, Years in sport [9.1±3.2]). We measured the key model variables of study in relation to sport motivation (Behavioral Regulation in Sport Questionnaire), and the motivation (adapted version of the Treatment Self-Regulation Questionnaire) and social cognitive patterns (the theory of planned behavior questionnaire) of doping avoidance. The data was analyzed by variance-based structural equation modeling with bootstrapping of 999 replications. The goodness-of-fit of the hypothesized model was acceptable. The bootstrapped parameter estimates revealed that autonomous motivation and amotivation in sport were positively associated with the corresponding types of motivation for the avoidance of doping. Autonomous motivation, subjective norm, and perceived behavioral control in doping avoidance fully mediated the relationship between autonomous motivation in sport and intention for doping avoidance. The findings support the tenets of the trans-contextual model, and explain how motivation in sport is related to athletes' motivation and intention with respect to anti-doping behaviors. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Contextual view of Johnson Ranch. Structures viewed from left to ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Contextual view of Johnson Ranch. Structures viewed from left to right; shop, barn 2 silo, residence, garage and residence 1, view to west. - Nunes Dairy, 9854 Bruceville Road, Elk Grove, Sacramento County, CA

Cultural, contextual, and intrapersonal predictors of risky sexual attitudes among urban African American girls in early adolescence.

PubMed

Belgrave, F Z; Van Oss Marin, B; Chambers, D B

2000-08-01

The role of cultural factors in explaining sexual attitudes among African American urban girls, aged 10-13 years, was investigated in this study. The authors predicted that girls with higher school interest, family cohesion, religiosity, and behavioral self-esteem would endorse less risky sexual attitudes. Also, older girls were expected to have more risky sexual attitudes than younger girls, and girls from 1- rather than 2-parent households were expected to have more risky sexual attitudes. The authors hypothesized that ethnic identity and gender role orientations would contribute to explaining variability in sexual attitudes after controlling for contextual and intrapersonal variables. A questionnaire containing measures of the study constructs was administered to 214 girls who were participants in a substance abuse prevention program. Pretest data were used in analyses. A final regression model accounted for 23% of the variance in sexual attitudes. Age and behavioral self-esteem were significant predictors, with younger teens and teens with higher behavioral self-esteem having less risky sexual attitudes. Cultural variables contributed to explaining variation in sexual attitudes after other variables were controlled for. Higher levels of ethnic identity were associated with less risky sexual attitudes. A masculine gender role orientation was associated with more risky sexual attitudes.

Stability of Recent and Remote Contextual Fear Memory

ERIC Educational Resources Information Center

Frankland, Paul W.; Ding, Hoi-Ki; Takahashi, Eiki; Suzuki, Akinobu; Kida, Satoshi; Silva, Alcino J.

2006-01-01

Following initial encoding, memories undergo a prolonged period of reorganization. While such reorganization may occur in many different memory systems, its purpose is not clear. Previously, we have shown that recall of recent contextual fear memories engages the dorsal hippocampus (dHPC). In contrast, recall of remote contextual fear memories…

Contextual cueing impairment in patients with age-related macular degeneration.

PubMed

Geringswald, Franziska; Herbik, Anne; Hoffmann, Michael B; Pollmann, Stefan

2013-09-12

Visual attention can be guided by past experience of regularities in our visual environment. In the contextual cueing paradigm, incidental learning of repeated distractor configurations speeds up search times compared to random search arrays. Concomitantly, fewer fixations and more direct scan paths indicate more efficient visual exploration in repeated search arrays. In previous work, we found that simulating a central scotoma in healthy observers eliminated this search facilitation. Here, we investigated contextual cueing in patients with age-related macular degeneration (AMD) who suffer from impaired foveal vision. AMD patients performed visual search using only their more severely impaired eye (n = 13) as well as under binocular viewing (n = 16). Normal-sighted controls developed a significant contextual cueing effect. In comparison, patients showed only a small nonsignificant advantage for repeated displays when searching with their worse eye. When searching binocularly, they profited from contextual cues, but still less than controls. Number of fixations and scan pattern ratios showed a comparable pattern as search times. Moreover, contextual cueing was significantly correlated with acuity in monocular search. Thus, foveal vision loss may lead to impaired guidance of attention by contextual memory cues.

Human cortical activity evoked by contextual processing in attentional orienting.

PubMed

Zhao, Shuo; Li, Chunlin; Uono, Shota; Yoshimura, Sayaka; Toichi, Motomi

2017-06-07

The ability to assess another person's direction of attention is paramount in social communication, many studies have reported a similar pattern between gaze and arrow cues in attention orienting. Neuroimaging research has also demonstrated no qualitative differences in attention to gaze and arrow cues. However, these studies were implemented under simple experiment conditions. Researchers have highlighted the importance of contextual processing (i.e., the semantic congruence between cue and target) in attentional orienting, showing that attentional orienting by social gaze or arrow cues could be modulated through contextual processing. Here, we examine the neural activity of attentional orienting by gaze and arrow cues in response to contextual processing using functional magnetic resonance imaging. The results demonstrated that the influence of neural activity through contextual processing to attentional orienting occurred under invalid conditions (when the cue and target were incongruent versus congruent) in the ventral frontoparietal network, although we did not identify any differences in the neural substrates of attentional orienting in contextual processing between gaze and arrow cues. These results support behavioural data of attentional orienting modulated by contextual processing based on the neurocognitive architecture.

26 CFR 1.414(v)-1 - Catch-up contributions.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 26 Internal Revenue 5 2014-04-01 2014-04-01 false Catch-up contributions. 1.414(v)-1 Section 1.414(v)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.414(v)-1 Catch-up...

26 CFR 1.414(v)-1 - Catch-up contributions.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 26 Internal Revenue 5 2013-04-01 2013-04-01 false Catch-up contributions. 1.414(v)-1 Section 1.414(v)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.414(v)-1 Catch-up...

26 CFR 1.414(v)-1 - Catch-up contributions.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 26 Internal Revenue 5 2012-04-01 2011-04-01 true Catch-up contributions. 1.414(v)-1 Section 1.414(v)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.414(v)-1 Catch-up...

26 CFR 1.414(v)-1 - Catch-up contributions.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 5 2011-04-01 2011-04-01 false Catch-up contributions. 1.414(v)-1 Section 1.414(v)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.414(v)-1 Catch-up...

26 CFR 1.414(v)-1 - Catch-up contributions.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 5 2010-04-01 2010-04-01 false Catch-up contributions. 1.414(v)-1 Section 1.414(v)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.414(v)-1 Catch-up contributions...

Experimental contextuality in classical light

NASA Astrophysics Data System (ADS)

Li, Tao; Zeng, Qiang; Song, Xinbing; Zhang, Xiangdong

2017-03-01

The Klyachko, Can, Binicioglu, and Shumovsky (KCBS) inequality is an important contextuality inequality in three-level system, which has been demonstrated experimentally by using quantum states. Using the path and polarization degrees of freedom of classical optics fields, we have constructed the classical trit (cetrit), tested the KCBS inequality and its geometrical form (Wright’s inequality) in this work. The projection measurement has been implemented, the clear violations of the KCBS inequality and its geometrical form have been observed. This means that the contextuality inequality, which is commonly used in test of the conflict between quantum theory and noncontextual realism, may be used as a quantitative tool in classical optical coherence to describe correlation characteristics of the classical fields.

V&V of MCNP 6.1.1 Beta Against Intermediate and High-Energy Experimental Data

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

Mashnik, Stepan G

This report presents a set of validation and verification (V&V) MCNP 6.1.1 beta results calculated in parallel, with MPI, obtained using its event generators at intermediate and high-energies compared against various experimental data. It also contains several examples of results using the models at energies below 150 MeV, down to 10 MeV, where data libraries are normally used. This report can be considered as the forth part of a set of MCNP6 Testing Primers, after its first, LA-UR-11-05129, and second, LA-UR-11-05627, and third, LA-UR-26944, publications, but is devoted to V&V with the latest, 1.1 beta version of MCNP6. The MCNP6more » test-problems discussed here are presented in the /VALIDATION_CEM/and/VALIDATION_LAQGSM/subdirectories in the MCNP6/Testing/directory. README files that contain short descriptions of every input file, the experiment, the quantity of interest that the experiment measures and its description in the MCNP6 output files, and the publication reference of that experiment are presented for every test problem. Templates for plotting the corresponding results with xmgrace as well as pdf files with figures representing the final results of our V&V efforts are presented. Several technical “bugs” in MCNP 6.1.1 beta were discovered during our current V&V of MCNP6 while running it in parallel with MPI using its event generators. These “bugs” are to be fixed in the following version of MCNP6. Our results show that MCNP 6.1.1 beta using its CEM03.03, LAQGSM03.03, Bertini, and INCL+ABLA, event generators describes, as a rule, reasonably well different intermediate- and high-energy measured data. This primer isn’t meant to be read from cover to cover. Readers may skip some sections and go directly to any test problem in which they are interested.« less

USEEIO v1.1-Matrices

EPA Science Inventory

This dataset provides the basic building blocks for the USEEIO v1.1 model and life cycle results per $1 (2013 USD) demand for all goods and services in the model in the producer's price (see BEA 2015). The methodology underlying USEEIO is described in Yang, Ingwersen et al., 2017...

Expert system verification and validation study: ES V/V Workshop

NASA Technical Reports Server (NTRS)

French, Scott; Hamilton, David

1992-01-01

The primary purpose of this document is to build a foundation for applying principles of verification and validation (V&V) of expert systems. To achieve this, some V&V as applied to conventionally implemented software is required. Part one will discuss the background of V&V from the perspective of (1) what is V&V of software and (2) V&V's role in developing software. Part one will also overview some common analysis techniques that are applied when performing V&V of software. All of these materials will be presented based on the assumption that the reader has little or no background in V&V or in developing procedural software. The primary purpose of part two is to explain the major techniques that have been developed for V&V of expert systems.

Context Matters: The Experience of 14 Research Teams in Systematically Reporting Contextual Factors Important for Practice Change

PubMed Central

Tomoaia-Cotisel, Andrada; Scammon, Debra L.; Waitzman, Norman J.; Cronholm, Peter F.; Halladay, Jacqueline R.; Driscoll, David L.; Solberg, Leif I.; Hsu, Clarissa; Tai-Seale, Ming; Hiratsuka, Vanessa; Shih, Sarah C.; Fetters, Michael D.; Wise, Christopher G.; Alexander, Jeffrey A.; Hauser, Diane; McMullen, Carmit K.; Scholle, Sarah Hudson; Tirodkar, Manasi A.; Schmidt, Laura; Donahue, Katrina E.; Parchman, Michael L.; Stange, Kurt C.

2013-01-01

PURPOSE We aimed to advance the internal and external validity of research by sharing our empirical experience and recommendations for systematically reporting contextual factors. METHODS Fourteen teams conducting research on primary care practice transformation retrospectively considered contextual factors important to interpreting their findings (internal validity) and transporting or reinventing their findings in other settings/situations (external validity). Each team provided a table or list of important contextual factors and interpretive text included as appendices to the articles in this supplement. Team members identified the most important contextual factors for their studies. We grouped the findings thematically and developed recommendations for reporting context. RESULTS The most important contextual factors sorted into 5 domains: (1) the practice setting, (2) the larger organization, (3) the external environment, (4) implementation pathway, and (5) the motivation for implementation. To understand context, investigators recommend (1) engaging diverse perspectives and data sources, (2) considering multiple levels, (3) evaluating history and evolution over time, (4) looking at formal and informal systems and culture, and (5) assessing the (often nonlinear) interactions between contextual factors and both the process and outcome of studies. We include a template with tabular and interpretive elements to help study teams engage research participants in reporting relevant context. CONCLUSIONS These findings demonstrate the feasibility and potential utility of identifying and reporting contextual factors. Involving diverse stakeholders in assessing context at multiple stages of the research process, examining their association with outcomes, and consistently reporting critical contextual factors are important challenges for a field interested in improving the internal and external validity and impact of health care research. PMID:23690380

Race Essentialism and Social Contextual Differences in Children’s Racial Stereotyping

PubMed Central

Pauker, Kristin; Xu, Yiyuan; Williams, Amanda; Biddle, Ashley Morris

2016-01-01

The authors explored the differential emergence and correlates of racial stereotyping in 136 children ages 4–11 years across two broad social contexts: Hawai‘i and Massachusetts. Children completed measures assessing race salience, race essentialism, and in-group and out-group stereotyping. Results indicated that the type of racial stereotypes emerging with age was context dependent. In both contexts in-group stereotyping increased with age. By contrast, there was only an age-related increase in out-group stereotyping in Massachusetts. Older children in Massachusetts reported more essentialist thinking (i.e., believing that race cannot change) than their counterparts in Hawai’i, which explained their higher out-group stereotyping. These results provide insight into the factors that may shape contextual differences in racial stereotyping. PMID:27684395

Serological Profile of Torque Teno Sus Virus Species 1 (TTSuV1) in Pigs and Antigenic Relationships between Two TTSuV1 Genotypes (1a and 1b), between Two Species (TTSuV1 and -2), and between Porcine and Human Anelloviruses

PubMed Central

Huang, Yao-Wei; Harrall, Kylie K.; Dryman, Barbara A.; Opriessnig, Tanja; Vaughn, Eric M.; Roof, Michael B.

2012-01-01

The family Anelloviridae includes human and animal torque teno viruses (TTVs) with extensive genetic diversity. The antigenic diversity among anelloviruses has never been assessed. Using torque teno sus virus (TTSuV) as a model, we describe here the first investigation of the antigenic relationships among different anelloviruses. Using a TTSuV genotype 1a (TTSuV1a) or TTSuV1b enzyme-linked immunosorbent assay (ELISA) based on the respective putative ORF1 capsid antigen and TTSuV1-specific real-time PCR, the combined serological and virological profile of TTSuV1 infection in pigs was determined and compared with that of TTSuV2. TTSuV1 is likely not associated with porcine circovirus-associated disease (PCVAD), because both the viral loads and antibody levels were not different between affected and unaffected pigs and because there was no synergistic effect of concurrent PCV2/TTSuV1 infections. We did observe a higher correlation of IgG antibody levels between anti-TTSuV1a and -TTSuV1b than between anti-TTSuV1a or -1b and anti-TTSuV2 antibodies in these sera, implying potential antigenic cross-reactivity. To confirm this, rabbit antisera against the putative capsid proteins of TTSuV1a, TTSuV1b, or TTSuV2 were generated, and the antigenic relationships among these TTSuVs were analyzed by an ELISA and by an immunofluorescence assay (IFA) using PK-15 cells transfected with one of the three TTSuV ORF1 constructs. The results demonstrate antigenic cross-reactivity between the two genotypes TTSuV1a and TTSuV1b but not between the two species TTSuV1a or -1b and TTSuV2. Furthermore, an anti-genogroup 1 human TTV antiserum did not react with any of the three TTSuV antigens. These results have important implications for an understanding of the diversity of anelloviruses as well as for the classification and vaccine development of TTSuVs. PMID:22811540

Contextual cueing in naturalistic scenes: Global and local contexts.

PubMed

Brockmole, James R; Castelhano, Monica S; Henderson, John M

2006-07-01

In contextual cueing, the position of a target within a group of distractors is learned over repeated exposure to a display with reference to a few nearby items rather than to the global pattern created by the elements. The authors contrasted the role of global and local contexts for contextual cueing in naturalistic scenes. Experiment 1 showed that learned target positions transfer when local information is altered but not when global information is changed. Experiment 2 showed that scene-target covariation is learned more slowly when local, but not global, information is repeated across trials than when global but not local information is repeated. Thus, in naturalistic scenes, observers are biased to associate target locations with global contexts. Copyright 2006 APA, all rights reserved.

Visual cues that are effective for contextual saccade adaptation.

PubMed

Azadi, Reza; Harwood, Mark R

2014-06-01

The accuracy of saccades, as maintained by saccade adaptation, has been shown to be context dependent: able to have different amplitude movements to the same retinal displacement dependent on motor contexts such as orbital starting location. There is conflicting evidence as to whether purely visual cues also effect contextual saccade adaptation and, if so, what function this might serve. We tested what visual cues might evoke contextual adaptation. Over 5 experiments, 78 naive subjects made saccades to circularly moving targets, which stepped outward or inward during the saccade depending on target movement direction, speed, or color and shape. To test if the movement or context postsaccade were critical, we stopped the postsaccade target motion (experiment 4) or neutralized the contexts by equating postsaccade target speed to an intermediate value (experiment 5). We found contextual adaptation in all conditions except those defined by color and shape. We conclude that some, but not all, visual cues before the saccade are sufficient for contextual adaptation. We conjecture that this visual contextuality functions to allow for different motor states for different coordinated movement patterns, such as coordinated saccade and pursuit motor planning. Copyright © 2014 the American Physiological Society.

Contextual knowledge reduces demands on working memory during reading.

PubMed

Miller, Lisa M Soederberg; Cohen, Jason A; Wingfield, Arthur

2006-09-01

An experiment is reported in which young, middle-aged, and older adults read and recalled ambiguous texts either with or without the topic title that supplied contextual knowledge. Within each of the age groups, the participants were divided into those with high or low working memory (WM) spans, with available WM capacity further manipulated by the presence or absence of an auditory target detection task concurrent with the reading task. Differences in reading efficiency (reading time per proposition recalled) between low WM span and high WM span groups were greater among readers who had access to contextual knowledge relative to those who did not, suggesting that contextual knowledge reduces demands on WM capacity. This position was further supported by the finding that increased age and attentional demands, two factors associated with reduced WM capacity, exaggerated the benefits of contextual knowledge on reading efficiency. The relative strengths of additional potential predictors of reading efficiency (e.g., interest, effort, and memory beliefs), along with knowledge, WM span, and age, are reported. Findings showed that contextual knowledge was the strongest predictor of reading efficiency even after controlling for the effects of all of the other predictors.

Visual cues that are effective for contextual saccade adaptation

PubMed Central

Azadi, Reza

2014-01-01

The accuracy of saccades, as maintained by saccade adaptation, has been shown to be context dependent: able to have different amplitude movements to the same retinal displacement dependent on motor contexts such as orbital starting location. There is conflicting evidence as to whether purely visual cues also effect contextual saccade adaptation and, if so, what function this might serve. We tested what visual cues might evoke contextual adaptation. Over 5 experiments, 78 naive subjects made saccades to circularly moving targets, which stepped outward or inward during the saccade depending on target movement direction, speed, or color and shape. To test if the movement or context postsaccade were critical, we stopped the postsaccade target motion (experiment 4) or neutralized the contexts by equating postsaccade target speed to an intermediate value (experiment 5). We found contextual adaptation in all conditions except those defined by color and shape. We conclude that some, but not all, visual cues before the saccade are sufficient for contextual adaptation. We conjecture that this visual contextuality functions to allow for different motor states for different coordinated movement patterns, such as coordinated saccade and pursuit motor planning. PMID:24647429

The strategic control of prospective memory monitoring in response to complex and probabilistic contextual cues.

PubMed

Bugg, Julie M; Ball, B Hunter

2017-07-01

Participants use simple contextual cues to reduce deployment of costly monitoring processes in contexts in which prospective memory (PM) targets are not expected. This study investigated whether this strategic monitoring pattern is observed in response to complex and probabilistic contextual cues. Participants performed a lexical decision task in which words or nonwords were presented in upper or lower locations on screen. The specific condition was informed that PM targets ("tor" syllable) would occur only in words in the upper location, whereas the nonspecific condition was informed that targets could occur in any location or word type. Context was blocked such that word type and location changed every 8 trials. In Experiment 1, the specific condition used the complex contextual cue to reduce monitoring in unexpected contexts relative to the nonspecific condition. This pattern largely was not evidenced when the complex contextual cue was probabilistic (Experiment 2). Experiment 3 confirmed that strategic monitoring is observed for a complex cue that is deterministic, but not one that is probabilistic. Additionally, Experiments 1 and 3 demonstrated a disadvantage associated with strategic monitoring-namely, that the specific condition was less likely to respond to a PM target in an unexpected context. Experiment 3 provided evidence that this disadvantage is attributable to impaired noticing of the target. The novel findings suggest use of a complex contextual cue per se is not a boundary condition for the strategic, context-specific allocation of monitoring processes to support prospective remembering; however, strategic monitoring is constrained by the predictive utility of the complex contextual cue.

Biphasic voltage-dependent inactivation of human NaV 1.3, 1.6 and 1.7 Na+ channels expressed in rodent insulin-secreting cells.

PubMed

Godazgar, Mahdieh; Zhang, Quan; Chibalina, Margarita V; Rorsman, Patrik

2018-05-01

explain the biphasic inactivation in Ins1 cells. In Ins1 cells, but never in the other cell types, widely different components of Na V inactivation (separated by 30 mV) were also observed following expression of a single type of Na V α-subunit. The more positive component exhibited a voltage dependence of inactivation similar to that found in HEK and CHO cells. We propose that biphasic Na V inactivation in insulin-secreting cells reflects insertion of channels in membrane domains that differ with regard to lipid and/or membrane protein composition. © 2018 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

Epinephrine increases contextual learning through activation of peripheral β2-adrenoceptors.

PubMed

Alves, Ester; Lukoyanov, Nikolay; Serrão, Paula; Moura, Daniel; Moreira-Rodrigues, Mónica

2016-06-01

Phenylethanolamine-N-methyltransferase knockout (Pnmt-KO) mice are unable to synthesize epinephrine and display reduced contextual fear. However, the precise mechanism responsible for impaired contextual fear learning in these mice is unknown. Our aim was to study the mechanism of epinephrine-dependent contextual learning. Wild-type (WT) or Pnmt-KO (129x1/SvJ) mice were submitted to a fear conditioning test either in the absence or in the presence of epinephrine, isoprenaline (non-selective β-adrenoceptor agonist), fenoterol (selective β2-adrenoceptor agonist), epinephrine plus sotalol (non-selective β-adrenoceptor antagonist), and dobutamine (selective β1-adrenoceptor agonist). Catecholamines were separated by reverse-phase HPLC and quantified by electrochemical detection. Blood glucose was measured by coulometry. Re-exposure to shock context induced higher freezing in WT and Pnmt-KO mice treated with epinephrine and fenoterol than in mice treated with vehicle. In addition, freezing response in Pnmt-KO mice was much lower than in WT mice. Freezing induced by epinephrine was blocked by sotalol in Pnmt-KO mice. Epinephrine and fenoterol treatment restored glycemic response in Pnmt-KO mice. Re-exposure to shock context did not induce a significant difference in freezing in Pnmt-KO mice treated with dobutamine and vehicle. Aversive memories are best retained if moderately high plasma epinephrine concentrations occur at the same moment as the aversive stimulus. In addition, epinephrine increases context fear learning by acting on peripheral β2-adrenoceptors, which may induce high levels of blood glucose. Since glucose crosses the blood-brain barrier, it may enhance hippocampal-dependent contextual learning.

The componential processing of fractions in adults and children: effects of stimuli variability and contextual interference

PubMed Central

Gabriel, Florence C.; Szücs, Dénes

2014-01-01

Recent studies have indicated that people have a strong tendency to compare fractions based on constituent numerators or denominators. This is called componential processing. This study explored whether componential processing was preferred in tasks involving high stimuli variability and high contextual interference, when fractions could be compared based either on the holistic values of fractions or on their denominators. Here, stimuli variability referred to the fact that fractions were not monotonous but diversiform. Contextual interference referred to the fact that the processing of fractions was interfered by other stimuli. To our ends, three tasks were used. In Task 1, participants compared a standard fraction 1/5 to unit fractions. This task was used as a low stimuli variability and low contextual interference task. In Task 2 stimuli variability was increased by mixing unit and non-unit fractions. In Task 3, high contextual interference was created by incorporating decimals into fractions. The RT results showed that the processing patterns of fractions were very similar for adults and children. In task 1 and task 3, only componential processing was utilzied. In contrast, both holistic processing and componential processing were utilized in task 2. These results suggest that, if individuals are presented with the opportunity to perform componential processing, both adults and children will tend to do so, even if they are faced with high variability of fractions or high contextual interference. PMID:25249995

The componential processing of fractions in adults and children: effects of stimuli variability and contextual interference.

PubMed

Zhang, Li; Fang, Qiaochu; Gabriel, Florence C; Szücs, Dénes

2014-01-01

Recent studies have indicated that people have a strong tendency to compare fractions based on constituent numerators or denominators. This is called componential processing. This study explored whether componential processing was preferred in tasks involving high stimuli variability and high contextual interference, when fractions could be compared based either on the holistic values of fractions or on their denominators. Here, stimuli variability referred to the fact that fractions were not monotonous but diversiform. Contextual interference referred to the fact that the processing of fractions was interfered by other stimuli. To our ends, three tasks were used. In Task 1, participants compared a standard fraction 1/5 to unit fractions. This task was used as a low stimuli variability and low contextual interference task. In Task 2 stimuli variability was increased by mixing unit and non-unit fractions. In Task 3, high contextual interference was created by incorporating decimals into fractions. The RT results showed that the processing patterns of fractions were very similar for adults and children. In task 1 and task 3, only componential processing was utilzied. In contrast, both holistic processing and componential processing were utilized in task 2. These results suggest that, if individuals are presented with the opportunity to perform componential processing, both adults and children will tend to do so, even if they are faced with high variability of fractions or high contextual interference.

Unfinished Student Answer in PISA Mathematics Contextual Problem

ERIC Educational Resources Information Center

Lutfianto, Moch.; Zulkardi; Hartono, Yusuf

2013-01-01

Solving mathematics contextual problems is one way that can be used to enable students to have the skills needed to live in the 21st century. Completion contextual problem requires a series of steps in order to properly answer the questions that are asked. The purpose of this study was to determine the steps performed students in solving…

A contextual perspective on talented female participants and their development in extracurricular STEM programs.

PubMed

Stoeger, Heidrun; Schirner, Sigrun; Laemmle, Lena; Obergriesser, Stefanie; Heilemann, Michael; Ziegler, Albert

2016-08-01

We advocate a more contextual perspective in giftedness research. In our view, doing so opens up three particularly interesting research areas, which we refer to as the participation issue, the effectiveness issue, and the interaction issue. To illustrate their utility, we examined characteristics of females participating in German high achiever-track secondary education who had applied for participation in a 1-year extracurricular e-mentoring program in science, technology, engineering, and mathematics (STEM) (n = 1237). Their characteristics were compared with male and female random-sample control groups. We assessed the effectiveness of the mentoring program by comparing the developmental trajectories of program participants with those of three control groups: applicants who were randomly chosen for later participation (waiting-list control group) and a female and a male control group. Finally, we examined whether differences in program effectiveness could be partially explained by characteristics of the interaction with the domain. Program applicants possessed more advantageous individual characteristics but, unexpectedly, less advantageous home and school environments than female and male members of the control groups. Program participation affected positive changes in certainty about career goals (independent of STEM) and in the number of STEM activities. The amount of STEM communication partially explained differences in program effectiveness. © 2016 New York Academy of Sciences.

Impaired contextual fear extinction and hippocampal synaptic plasticity in adult rats induced by prenatal morphine exposure.

PubMed

Tan, Ji-Wei; Duan, Ting-Ting; Zhou, Qi-Xin; Ding, Ze-Yang; Jing, Liang; Cao, Jun; Wang, Li-Ping; Mao, Rong-Rong; Xu, Lin

2015-07-01

Prenatal opiate exposure causes a series of neurobehavioral disturbances by affecting brain development. However, the question of whether prenatal opiate exposure increases vulnerability to memory-related neuropsychiatric disorders in adult offspring remains largely unknown. Here, we found that rats prenatally exposed to morphine (PM) showed impaired acquisition but enhanced maintenance of contextual fear memory compared with control animals that were prenatally exposed to saline (PS). The impairment of acquisition was rescued by increasing the intensity of footshocks (1.2 mA rather than 0.8 mA). Meanwhile, we also found that PM rats exhibited impaired extinction of contextual fear, which is associated with enhanced maintenance of fear memory. The impaired extinction lasted for 1 week following extinction training. Furthermore, PM rats exhibited reduced anxiety-like behavior in the elevated plus-maze and light/dark box test without differences in locomotor activity. These alterations in PM rats were mirrored by abnormalities in synaptic plasticity in the Schaffer collateral-CA1 synapses of the hippocampus in vivo. PS rats showed blocked long-term potentiation and enabled long-term depression in CA1 synapses following contextual fear conditioning, while prenatal morphine exposure restricted synaptic plasticity in CA1 synapses. The smaller long-term potentiation in PM rats was not further blocked by contextual fear conditioning, and the long-term depression enabled by contextual fear conditioning was abolished. Taken together, our results provide the first evidence suggesting that prenatal morphine exposure may increase vulnerability to fear memory-related neuropsychiatric disorders in adulthood. © 2014 Society for the Study of Addiction.

Hippocampal Mek/Erk signaling mediates extinction of contextual freezing behavior.

PubMed

Fischer, Andre; Radulovic, Marko; Schrick, Christina; Sananbenesi, Farahnaz; Godovac-Zimmermann, Jasminka; Radulovic, Jelena

2007-01-01

Fear memories elicit multiple behavioral responses, encompassing avoidance, or behavioral inhibition in response to threatening contexts. Context-specific freezing, reflecting fear-induced behavioral inhibition, has been proposed as one of the main risks factors for the development of anxiety disorders. We attempted to define the key hippocampal mediators of extinction in a mouse model of context-dependent freezing. Nine-week-old male C57BL/6J mice were trained and tested for contextual fear conditioning and extinction. Freezing behavior scored by unbiased sampling, was used as an index of fear. Proteomic, immunoblot, and immunohistochemical approaches were employed to identify, verify, and analyze the alterations of the hippocampal extracellular signal-regulated kinases 1 and 2 (Erk-1/2). Targeted pharmacological inhibition of the Erk-1/2 activating kinase, the mitogen activated and extracellular signal-regulated kinase (Mek), served to establish the role of Mek/Erk signaling in extinction. When compared to acquisition, extinction of contextual freezing triggered a rapid activation of Erk-1/2 showing a distinctive time-course, nuclear localization, and subcellular isoform distribution. These differences suggested that the upstream regulation and downstream effects of this pathway might be specific for each process. Dorsohippocampal injections of the Mek inhibitors U0126 (0.5 microg/site) and PD98059 (1.5 microg/site) immediately after the nonreinforced trials prevented Erk-1/2 activation and significantly impaired extinction. This effect was dissociable from potential actions on memory retrieval or reconsolidation. On the basis of these findings, we propose that hippocampal Mek/Erk signaling might serve as one of the key mediators of contextual fear extinction.

Contextual signals in visual cortex.

PubMed

Khan, Adil G; Hofer, Sonja B

2018-06-05

Vision is an active process. What we perceive strongly depends on our actions, intentions and expectations. During visual processing, these internal signals therefore need to be integrated with the visual information from the retina. The mechanisms of how this is achieved by the visual system are still poorly understood. Advances in recording and manipulating neuronal activity in specific cell types and axonal projections together with tools for circuit tracing are beginning to shed light on the neuronal circuit mechanisms of how internal, contextual signals shape sensory representations. Here we review recent work, primarily in mice, that has advanced our understanding of these processes, focusing on contextual signals related to locomotion, behavioural relevance and predictions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Negative emotional stimuli reduce contextual cueing but not response times in inefficient search.

PubMed

Kunar, Melina A; Watson, Derrick G; Cole, Louise; Cox, Angeline

2014-02-01

In visual search, previous work has shown that negative stimuli narrow the focus of attention and speed reaction times (RTs). This paper investigates these two effects by first asking whether negative emotional stimuli narrow the focus of attention to reduce the learning of a display context in a contextual cueing task and, second, whether exposure to negative stimuli also reduces RTs in inefficient search tasks. In Experiment 1, participants viewed either negative or neutral images (faces or scenes) prior to a contextual cueing task. In a typical contextual cueing experiment, RTs are reduced if displays are repeated across the experiment compared with novel displays that are not repeated. The results showed that a smaller contextual cueing effect was obtained after participants viewed negative stimuli than when they viewed neutral stimuli. However, in contrast to previous work, overall search RTs were not faster after viewing negative stimuli (Experiments 2 to 4). The findings are discussed in terms of the impact of emotional content on visual processing and the ability to use scene context to help facilitate search.

Contextual Risk and Parenting as Predictors of Effortful Control and Social Competence in Preschool Children

ERIC Educational Resources Information Center

Lengua, Liliana J.; Honorado, Elizabeth; Bush, Nicole R.

2007-01-01

Using a short-term longitudinal design (6 months), this study examined cumulative contextual risk as a predictor of effortful control (EC) and social competence in a community sample of children (N = 80, ages 33-40 months at time 1). Maternal parenting was examined as a mediator of contextual risk. EC was assessed using laboratory tasks, and…

Perceived participation and autonomy: aspects of functioning and contextual factors predicting participation after stroke.

PubMed

Fallahpour, Mandana; Tham, Kerstin; Joghataei, Mohammad Taghi; Jonsson, Hans

2011-04-01

To describe perceived participation and autonomy among a sample of persons with stroke in Iran and to identify different aspects of functioning and contextual factors predicting participation after stroke. A cross-sectional study. A total of 102 persons, between 27 and 75 years of age, diagnosed with first-ever stroke. Participants were assessed for different aspects of functioning, contextual factors and health conditions. Participation was assessed using the Persian version of the Impact on Participation and Autonomy questionnaire. This study demonstrated that the majority of the study population perceived their participation and autonomy to be good to fair in the different domains of their participation, but not with respect to the autonomy outdoors domain. In addition, physical function was found to be the most important variable predicting performance-based participation, whereas mood state was the most important variable predicting social-based participation. The results emphasize the importance of physical function, mood state and access to caregiving services as predictors of participation in everyday life after stroke. Whilst there are two dimensions of participation in this Persian sample of persons with stroke, the factors explaining participation seem to be the same across the cultures.

4. CONTEXTUAL VIEW OF THE VILLAGE COMPLEX, SHOWING COTTAGE NO. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. CONTEXTUAL VIEW OF THE VILLAGE COMPLEX, SHOWING COTTAGE NO. 1 IN FOREGROUND, LOOKING SOUTH ALONG THE ENTRANCE DRIVEWAY (OLD CHARLES ROAD) - Nine Mile Hydroelectric Development, State Highway 291 along Spokane River, Nine Mile Falls, Spokane County, WA

Contextual view looking down clubhouse drive. Showing west elevation of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Contextual view looking down clubhouse drive. Showing west elevation of H1 on right; camera facing east. - Mare Island Naval Shipyard, Hospital Headquarters, Johnson Lane, west side at intersection of Johnson Lane & Cossey Street, Vallejo, Solano County, CA

Do Contextual Effects Bias Kentucky School District Accountability Index Scores? Occasional Research Paper No. 1.

ERIC Educational Resources Information Center

Reeves, Edward B.

The system of high-stakes accountability in the Kentucky public schools raises the question of whether teachers and administrators should be held accountable if test scores are influenced by external factors over which educators have no control. This study investigates whether such external factors , or "contextual effects," bias the…

Exhibition of Monogamy Relations between Entropic Non-contextuality Inequalities

NASA Astrophysics Data System (ADS)

Zhu, Feng; Zhang, Wei; Huang, Yi-Dong

2017-06-01

We exhibit the monogamy relation between two entropic non-contextuality inequalities in the scenario where compatible projectors are orthogonal. We show the monogamy relation can be exhibited by decomposing the orthogonality graph into perfect induced subgraphs. Then we find two entropic non-contextuality inequalities are monogamous while the KCBS-type non-contextuality inequalities are not if the orthogonality graphs of the observable sets are two odd cycles with two shared vertices. Supported by 973 Programs of China under Grant Nos. 2011CBA00303 and 2013CB328700, Basic Research Foundation of Tsinghua National Laboratory for Information Science and Technology (TNList)

R-Ras contributes to LTP and contextual discrimination.

PubMed

Darcy, M J; Jin, S-X; Feig, L A

2014-09-26

The ability to discriminate between closely related contexts is a specific form of hippocampal-dependent learning that may be impaired in certain neurodegenerative disorders such as Alzheimer's and Down Syndrome. However, signaling pathways regulating this form of learning are poorly understood. Previous studies have shown that the calcium-dependent exchange factor Ras-GRF1, an activator of Rac, Ras and R-Ras GTPases, is important for this form of learning and memory. Moreover, the ability to discriminate contexts was linked to the ability of Ras-GRF1 to promote high-frequency stimulation long-term potentiation (HFS-LTP) via the activation of p38 Map kinase. Here, we show that R-Ras is involved in this form of learning by using virally-delivered miRNAs targeting R-Ras into the CA1 region of the dorsal hippocampus and observing impaired contextual discrimination. Like the loss of GRF1, knockdown of R-Ras in the CA1 also impairs the induction of HFS-LTP and p38 Map kinase. Nevertheless, experiments indicate that this involvement of R-Ras in HFS-LTP that is required for contextual discrimination is independent of Ras-GRF1. Thus, R-Ras is a novel regulator of a form of hippocampal-dependent LTP as well as learning and memory that is affected in certain forms of neurodegenerative diseases. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

R-Ras Contributes to LTP and Contextual Discrimination

PubMed Central

Darcy, Michael J.; Jin, Shan-Xue; Feig, Larry A.

2014-01-01

The ability to discriminate between closely related contexts is a specific form of hippocampal-dependent learning that may be impaired in certain neurodegenerative disorders such as Alzheimer's and Down Syndrome. However, signaling pathways regulating this form of learning are poorly understood. Previous studies have shown that the calcium-dependent exchange factor Ras-GRF1, an activator of Rac, Ras and R-Ras GTPases, is important for this form of learning and memory. Moreover, the ability to discriminate contexts was linked to the ability of Ras-GRF1 to promote high-frequency stimulation (HFS)-LTP via the activation of p38 Map kinase. Here, we show that R-Ras is involved in this form of learning by using virally-delivered miRNAs targeting R-Ras into the CA1 region of dorsal hippocampus and observing impaired contextual discrimination. Like the loss of GRF1, knockdown of R-Ras in the CA1 also impairs the induction of HFS-LTP and p38 Map kinase. Nevertheless, experiments indicate that this involvement of R-Ras in HFS-LTP that is required for contextual discrimination is independent of Ras-GRF1. Thus, R-Ras is a novel regulator of a form of hippocampal-dependent LTP as well as learning and memory that is affected in certain forms of neurodegenerative diseases. PMID:25043327

Periaqueductal gray knockdown of V2, not V1a and V1b receptor influences nociception in the rat. yj6676@yahoo.com.

PubMed

Yang, Jun; Yang, Yu; Chen, Jian-Min; Wang, Gen; Xu, Hong-Tao; Liu, Wen-Yan; Lin, Bao-Cheng

2007-01-01

Our pervious study has proved that arginine vasopressin (AVP) in periaqueductal gray (PAG) plays a role in antinociception. After establishing a model of local special gene knockdown, the nociceptive effect of vasopressin receptor subunit in PAG was investigated in the rat. Microinjection of short-interfering RNA (siRNA) into PAG, which targeted vasopressin receptor subtypes (V(1a), V(1b) and V(2)), locally weakened the associated mRNA expression and depressed the related receptor synthesis in a dose-dependent manner, in which the significant inhibitive effect occurred on from 7th day to 14th day following 1microg or 2microg siRNA administration. PAG knockdown of V(2) receptor gene markedly decreased pain threshold in from 6th day to 13th day after siRNA administration, whereas local knockdown of either V(1a) or V(1b) receptor gene could not influence pain threshold. The data suggest that V(2) rather than V(1a) and V(1b) receptor in PAG involves in nociception.

Visual Displays and Contextual Presentations in Computer-Based Instruction.

ERIC Educational Resources Information Center

Park, Ok-choon

1998-01-01

Investigates the effects of two instructional strategies, visual display (animation, and static graphics with and without motion cues) and contextual presentation, in the acquisition of electronic troubleshooting skills using computer-based instruction. Study concludes that use of visual displays and contextual presentation be based on the…

Race Essentialism and Social Contextual Differences in Children's Racial Stereotyping.

PubMed

Pauker, Kristin; Xu, Yiyuan; Williams, Amanda; Biddle, Ashley M

2016-09-01

The authors explored the differential emergence and correlates of racial stereotyping in 136 children ages 4-11 years across two broad social contexts: Hawai'i and Massachusetts. Children completed measures assessing race salience, race essentialism, and in-group and out-group stereotyping. Results indicated that the type of racial stereotypes emerging with age was context dependent. In both contexts in-group stereotyping increased with age. In contrast, there was only an age-related increase in out-group stereotyping in Massachusetts. Older children in Massachusetts reported more essentialist thinking (i.e., believing that race cannot change) than their counterparts in Hawai'i, which explained their higher out-group stereotyping. These results provide insight into the factors that may shape contextual differences in racial stereotyping. © 2016 The Authors. Child Development © 2016 Society for Research in Child Development, Inc.

Effects of Forward and Backward Contextual Elaboration on Lexical Inferences: Evidence from a Semantic Relatedness Judgment Task

ERIC Educational Resources Information Center

Hamada, Akira

2015-01-01

Three experiments examined whether the process of lexical inferences differs according to the direction of contextual elaboration using a semantic relatedness judgment task. In Experiment 1, Japanese university students read English sentences where target unknown words were semantically elaborated by prior contextual information (forward lexical…

Transfer of contextual cueing in full-icon display remapping.

PubMed

Shi, Zhuanghua; Zang, Xuelian; Jia, Lina; Geyer, Thomas; Müller, Hermann J

2013-02-25

Invariant spatial context can expedite visual search, an effect that is known as contextual cueing (e.g., Chun & Jiang, 1998). However, disrupting learned display configurations abolishes the effect. In current touch-based mobile devices, such as the iPad, icons are shuffled and remapped when the display mode is changed. However, such remapping also disrupts the spatial relationships between icons. This may hamper usability. In the present study, we examined the transfer of contextual cueing in four different methods of display remapping: position-order invariant, global rotation, local invariant, and central invariant. We used full-icon landscape mode for training and both landscape and portrait modes for testing, to check whether the cueing transfers to portrait mode. The results showed transfer of contextual cueing but only with the local invariant and the central invariant remapping methods. We take the results to mean that the predictability of target locations is a crucial factor for the transfer of contextual cueing and thus icon remapping design for mobile devices.

2. CONTEXTUAL VIEW OF THE NINE MILE HED, SHOWING DAM ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. CONTEXTUAL VIEW OF THE NINE MILE HED, SHOWING DAM AND POWERHOUSE IN FOREGROUND, AND COTTAGES NO. 1 AND 2 IN RIGHT BACKGROUND, LOOKING WEST - Nine Mile Hydroelectric Development, State Highway 291 along Spokane River, Nine Mile Falls, Spokane County, WA

Specificity of V1-V2 Orientation Networks in the Primate Visual Cortex

PubMed Central

Roe, Anna W.; Ts'o, Daniel Y.

2015-01-01

The computation of texture and shape involves integration of features of various orientations. Orientation networks within V1 tend to involve cells which share similar orientation selectivity. However, emergent properties in V2 require the integration of multiple orientations. We now show that, unlike interactions within V1, V1-V2 orientation interactions are much less synchronized and are not necessarily orientation dependent. We find V1-V2 orientation networks are of two types: a more tightly synchronized, orientation-preserving network and a less synchronized orientation-diverse network. We suggest that such diversity of V1-V2 interactions underlies the spatial and functional integration required for computation of higher order contour and shape in V2. PMID:26314798

Animacy-based predictions in language comprehension are robust: contextual cues modulate but do not nullify them.

PubMed

Muralikrishnan, R; Schlesewsky, Matthias; Bornkessel-Schlesewsky, Ina

2015-05-22

Couldn׳t a humble coconut hurt a gardener? At least in the first instance, the brain seems to assume that it should not: we perceive inanimate entities such as coconuts as poor event instigators ("Actors"). Ideally, entities causing a change in another entity should be animate and this assumption not only influences event perception but also carries over to language comprehension. We present three auditory event-related brain potential (ERP) studies on the processing of inanimate and animate subjects and objects in simple transitive sentences in Tamil. ERP responses were measured at the second argument (event participant) in all three studies. Experiment 1 employed all possible animacy combinations of Actors and Undergoers (affected participants) in Actor- and Undergoer-initial verb-final orders. Experiments 2 and 3 employed a fairly novel context design that enabled us to compare ERPs evoked by identical auditory material to differing contextual expectations: Experiment 2 focussed on constructions in which an inanimate Actor acts upon an inanimate Undergoer, whereas Experiment 3 examined whether and how a preceding context modulates the prediction for an ideal Actor. Results showed an N400 effect when the prediction for an ideal (animate) Actor following an Undergoer was not met, thus further supporting the cross-linguistically robust nature of animacy preferences. In addition, though specific contextual cues that are indicative of a forthcoming non-ideal Actor may reduce this negativity in comparison to when such cues are not available, they nevertheless do not nullify it, suggesting that animacy-based predictions are stronger than contextual cues in online language comprehension. Copyright © 2014 Elsevier B.V. All rights reserved.

Contextual Modulation is Related to Efficiency in a Spiking Network Model of Visual Cortex.

PubMed

Sharifian, Fariba; Heikkinen, Hanna; Vigário, Ricardo; Vanni, Simo

2015-01-01

In the visual cortex, stimuli outside the classical receptive field (CRF) modulate the neural firing rate, without driving the neuron by themselves. In the primary visual cortex (V1), such contextual modulation can be parametrized with an area summation function (ASF): increasing stimulus size causes first an increase and then a decrease of firing rate before reaching an asymptote. Earlier work has reported increase of sparseness when CRF stimulation is extended to its surroundings. However, there has been no clear connection between the ASF and network efficiency. Here we aimed to investigate possible link between ASF and network efficiency. In this study, we simulated the responses of a biomimetic spiking neural network model of the visual cortex to a set of natural images. We varied the network parameters, and compared the V1 excitatory neuron spike responses to the corresponding responses predicted from earlier single neuron data from primate visual cortex. The network efficiency was quantified with firing rate (which has direct association to neural energy consumption), entropy per spike and population sparseness. All three measures together provided a clear association between the network efficiency and the ASF. The association was clear when varying the horizontal connectivity within V1, which influenced both the efficiency and the distance to ASF, DAS. Given the limitations of our biophysical model, this association is qualitative, but nevertheless suggests that an ASF-like receptive field structure can cause efficient population response.

Any Ontological Model of the Single Qubit Stabilizer Formalism must be Contextual

NASA Astrophysics Data System (ADS)

Lillystone, Piers; Wallman, Joel J.

Quantum computers allow us to easily solve some problems classical computers find hard. Non-classical improvements in computational power should be due to some non-classical property of quantum theory. Contextuality, a more general notion of non-locality, is a necessary, but not sufficient, resource for quantum speed-up. Proofs of contextuality can be constructed for the classically simulable stabilizer formalism. Previous proofs of stabilizer contextuality are known for 2 or more qubits, for example the Mermin-Peres magic square. In the work presented we extend these results and prove that any ontological model of the single qubit stabilizer theory must be contextual, as defined by R. Spekkens, and give a relation between our result and the Mermin-Peres square. By demonstrating that contextuality is present in the qubit stabilizer formalism we provide further insight into the contextuality present in quantum theory. Understanding the contextuality of classical sub-theories will allow us to better identify the physical properties of quantum theory required for computational speed up. This research was supported by CIFAR, the Government of Ontario, and the Government of Canada through NSERC and Industry Canada.

The roles of Eph receptors in contextual fear conditioning memory formation.

PubMed

Dines, Monica; Grinberg, Svetlana; Vassiliev, Maria; Ram, Alon; Tamir, Tal; Lamprecht, Raphael

2015-10-01

Eph receptors regulate glutamate receptors functions, neuronal morphology and synaptic plasticity, cellular events believed to be involved in memory formation. In this study we aim to explore the roles of Eph receptors in learning and memory. Toward that end, we examined the roles of EphB2 and EphA4 receptors, key regulators of synaptic functions, in fear conditioning memory formation. We show that mice lacking EphB2 (EphB2(-/-)) are impaired in short- and long-term contextual fear conditioning memory. Mice that express a carboxy-terminally truncated form of EphB2 that lacks forward signaling, instead of the full EphB2, are impaired in long-term, but not short-term, contextual fear conditioning memory. Long-term contextual fear conditioning memory is attenuated in CaMKII-cre;EphA4(lx/-) mice where EphA4 is removed from all pyramidal neurons of the forebrain. Mutant mice with targeted kinase-dead EphA4 (EphA4(KD)) exhibit intact long-term contextual fear conditioning memory showing that EphA4 kinase-mediated forward signaling is not needed for contextual fear memory formation. The ability to form long-term conditioned taste aversion (CTA) memory is not impaired in the EphB2(-/-) and CaMKII-cre;EphA4(lx/-) mice. We conclude that EphB2 forward signaling is required for long-term contextual fear conditioning memory formation. In contrast, EphB2 mediates short-term contextual fear conditioning memory formation in a forward signaling-independent manner. EphA4 mediates long-term contextual fear conditioning memory formation in a kinase-independent manner. Copyright © 2015 Elsevier Inc. All rights reserved.

Improving Mathematical Problem-Solving Ability and Self-Confidence of High School Students through Contextual Learning Model

ERIC Educational Resources Information Center

Surya, Edy; Putri, Feria Andriana; Mukhtar

2017-01-01

The purposes of this study are: (1) to know if students' mathematical problem-solving ability taught by contextual learning model is higher than students taught by expository learning, (2) to know if students' self-confidence taught by contextual learning model is higher than students taught by expository learning, (3) to know if there is…

A Multiple Case Study of College-Contextualized Mathematics Curriculum

ERIC Educational Resources Information Center

Valenzuela, Hector

2018-01-01

Contextualization is a method used for mathematics curriculum design within lesson plans and as a pedagogical practice in face-to-face classes. Many researchers are studying the effects of using contextualization in the teaching and the learning process for mathematics (Bottge & Cho, 2013; Perin, 2011; Young, Hodge, Edwards, & Leising,…

A qualitative study of contextual factors' impact on measures to reduce surgery cancellations.

PubMed

Hovlid, Einar; Bukve, Oddbjørn

2014-05-13

Contextual factors influence quality improvement outcomes. Understanding this influence is important when adapting and implementing interventions and translating improvements into new settings. To date, there is limited knowledge about how contextual factors influence quality improvement processes. In this study, we explore how contextual factors affected measures to reduce surgery cancellations, which are a persistent problem in healthcare. We discuss the usefulness of the theoretical framework provided by the model for understanding success in quality (MUSIQ) for this kind of research. We performed a qualitative case study at Førde Hospital, Norway, where we had previously demonstrated a reduction in surgery cancellations. We interviewed 20 clinicians and performed content analysis to explore how contextual factors affected measures to reduce cancellations of planned surgeries. We identified three common themes concerning how contextual factors influenced the change process: 1) identifying a need to change, 2) facilitating system-wide improvement, and 3) leader involvement and support. Input from patients helped identify a need to change and contributed to the consensus that change was necessary. Reducing cancellations required improving the clinical system. This improvement process was based on a strategy that emphasized the involvement of frontline clinicians in detecting and improving system problems. Clinicians shared information about their work by participating in improvement teams to develop a more complete understanding of the clinical system and its interdependencies. This new understanding allowed clinicians to detect system problems and design adequate interventions. Middle managers' participation in the improvement teams and in regular work processes was important for successfully implementing and adapting interventions. Contextual factors interacted with one another and with the interventions to facilitate changes in the clinical system, reducing

MTR STACK, TRA710, CONTEXTUAL VIEW, CAMERA FACING SOUTH. PERIMETER SECURITY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

MTR STACK, TRA-710, CONTEXTUAL VIEW, CAMERA FACING SOUTH. PERIMETER SECURITY FENCE AND SECURITY LIGHTING IN VIEW AT LEFT. INL NEGATIVE NO. HD52-1-1. Mike Crane, Photographer, 5/2005 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Entourage: Visualizing Relationships between Biological Pathways using Contextual Subsets

PubMed Central

Lex, Alexander; Partl, Christian; Kalkofen, Denis; Streit, Marc; Gratzl, Samuel; Wassermann, Anne Mai; Schmalstieg, Dieter; Pfister, Hanspeter

2014-01-01

Biological pathway maps are highly relevant tools for many tasks in molecular biology. They reduce the complexity of the overall biological network by partitioning it into smaller manageable parts. While this reduction of complexity is their biggest strength, it is, at the same time, their biggest weakness. By removing what is deemed not important for the primary function of the pathway, biologists lose the ability to follow and understand cross-talks between pathways. Considering these cross-talks is, however, critical in many analysis scenarios, such as judging effects of drugs. In this paper we introduce Entourage, a novel visualization technique that provides contextual information lost due to the artificial partitioning of the biological network, but at the same time limits the presented information to what is relevant to the analyst’s task. We use one pathway map as the focus of an analysis and allow a larger set of contextual pathways. For these context pathways we only show the contextual subsets, i.e., the parts of the graph that are relevant to a selection. Entourage suggests related pathways based on similarities and highlights parts of a pathway that are interesting in terms of mapped experimental data. We visualize interdependencies between pathways using stubs of visual links, which we found effective yet not obtrusive. By combining this approach with visualization of experimental data, we can provide domain experts with a highly valuable tool. We demonstrate the utility of Entourage with case studies conducted with a biochemist who researches the effects of drugs on pathways. We show that the technique is well suited to investigate interdependencies between pathways and to analyze, understand, and predict the effect that drugs have on different cell types. Fig. 1Entourage showing the Glioma pathway in detail and contextual information of multiple related pathways. PMID:24051820

Affective theory of mind inferences contextually influence the recognition of emotional facial expressions.

PubMed

Stewart, Suzanne L K; Schepman, Astrid; Haigh, Matthew; McHugh, Rhian; Stewart, Andrew J

2018-03-14

The recognition of emotional facial expressions is often subject to contextual influence, particularly when the face and the context convey similar emotions. We investigated whether spontaneous, incidental affective theory of mind inferences made while reading vignettes describing social situations would produce context effects on the identification of same-valenced emotions (Experiment 1) as well as differently-valenced emotions (Experiment 2) conveyed by subsequently presented faces. Crucially, we found an effect of context on reaction times in both experiments while, in line with previous work, we found evidence for a context effect on accuracy only in Experiment 1. This demonstrates that affective theory of mind inferences made at the pragmatic level of a text can automatically, contextually influence the perceptual processing of emotional facial expressions in a separate task even when those emotions are of a distinctive valence. Thus, our novel findings suggest that language acts as a contextual influence to the recognition of emotional facial expressions for both same and different valences.

Fundamental monogamy relation between contextuality and nonlocality.

PubMed

Kurzyński, Paweł; Cabello, Adán; Kaszlikowski, Dagomir

2014-03-14

We show that the no-disturbance principle imposes a tradeoff between locally contextual correlations violating the Klyachko-Can-Biniciogˇlu-Shumovski inequality and spatially separated correlations violating the Clauser-Horne-Shimony-Holt inequality. The violation of one inequality forbids the violation of the other. We also obtain the corresponding monogamy relation imposed by quantum theory for a qutrit-qubit system. Our results show the existence of fundamental monogamy relations between contextuality and nonlocality that suggest that entanglement might be a particular form of a more fundamental resource.

Can the differences in the determinations of V(ub) and V(cb) be explained by new physics?

PubMed

Crivellin, Andreas; Pokorski, Stefan

2015-01-09

The precise determination of the Cabibbo-Kobayashi-Maskawa elements V(ub) and V(ub) is crucial for any new physics analysis in the flavor sector. Their values can be determined from several tree-level decays: V(ub) can be extracted from B→Dℓν and B→D(*)ℓν while V(ub) can be obtained from B→πℓν, B→ρℓν, and B→τν. In addition, for both V(ub) and V(ub) an inclusive determination is available. There is a long lasting discrepancy between the inclusive and exclusive determinations which recently even increased for V(ub) above the 3σ level. In this Letter we study the possible effect of new physics on the inclusive and exclusive determination of V(ub) and V(ub) in a model independent way. We find that there is only one operator corresponding to a modified W coupling which can achieve this. However, respecting SU(2) gauge invariance at the high scale this would lead to very large violations of the Z to bb̅ coupling not compatible with experiment. Therefore, we conclude that a new physics explanation of the difference between the inclusive and exclusive determination of V(ub) and V(ub) is currently ruled out. Therefore, the discrepancies must be due to underestimated uncertainties in the theoretical and/or the experimental analysis.

Impact of Contextual Factors on Prostate Cancer Risk and Outcomes

DTIC Science & Technology

2013-07-01

framework with random effects (“frailty models”) while the case-control analyses (Aim 4) will use multilevel unconditional logistic regression models...contextual-level SES on prostate cancer risk within racial/ethnic groups. The survival analyses (Aims 1-3) will utilize a proportional hazards regression

Contextual Compression of Large-Scale Wind Turbine Array Simulations

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

Gruchalla, Kenny M; Brunhart-Lupo, Nicholas J; Potter, Kristin C

Data sizes are becoming a critical issue particularly for HPC applications. We have developed a user-driven lossy wavelet-based storage model to facilitate the analysis and visualization of large-scale wind turbine array simulations. The model stores data as heterogeneous blocks of wavelet coefficients, providing high-fidelity access to user-defined data regions believed the most salient, while providing lower-fidelity access to less salient regions on a block-by-block basis. In practice, by retaining the wavelet coefficients as a function of feature saliency, we have seen data reductions in excess of 94 percent, while retaining lossless information in the turbine-wake regions most critical to analysismore » and providing enough (low-fidelity) contextual information in the upper atmosphere to track incoming coherent turbulent structures. Our contextual wavelet compression approach has allowed us to deliver interative visual analysis while providing the user control over where data loss, and thus reduction in accuracy, in the analysis occurs. We argue this reduced but contextualized representation is a valid approach and encourages contextual data management.« less

Orientation-specific contextual modulation of the fMRI BOLD response to luminance and chromatic gratings in human visual cortex.

PubMed

McDonald, J Scott; Seymour, Kiley J; Schira, Mark M; Spehar, Branka; Clifford, Colin W G

2009-05-01

The responses of orientation-selective neurons in primate visual cortex can be profoundly affected by the presence and orientation of stimuli falling outside the classical receptive field. Our perception of the orientation of a line or grating also depends upon the context in which it is presented. For example, the perceived orientation of a grating embedded in a surround tends to be repelled from the predominant orientation of the surround. Here, we used fMRI to investigate the basis of orientation-specific surround effects in five functionally-defined regions of visual cortex: V1, V2, V3, V3A/LO1 and hV4. Test stimuli were luminance-modulated and isoluminant gratings that produced responses similar in magnitude. Less BOLD activation was evident in response to gratings with parallel versus orthogonal surrounds across all the regions of visual cortex investigated. When an isoluminant test grating was surrounded by a luminance-modulated inducer, the degree of orientation-specific contextual modulation was no larger for extrastriate areas than for V1, suggesting that the observed effects might originate entirely in V1. However, more orientation-specific modulation was evident in extrastriate cortex when both test and inducer were luminance-modulated gratings than when the test was isoluminant; this difference was significant in area V3. We suggest that the pattern of results in extrastriate cortex may reflect a refinement of the orientation-selectivity of surround suppression specific to the colour of the surround or, alternatively, processes underlying the segmentation of test and inducer by spatial phase or orientation when no colour cue is available.

Individual and contextual factors related to dental caries in underprivileged Brazilian adolescents.

PubMed

Vazquez, Fabiana de Lima; Cortellazzi, Karine Laura; Kaieda, Armando Koichiro; Bulgareli, Jaqueline Vilela; Mialhe, Fabio Luiz; Ambrosano, Glaucia Maria Bovi; da Silva Tagliaferro, Elaine Pereira; Guerra, Luciane Miranda; de Castro Meneghim, Marcelo; Pereira, Antonio Carlos

2015-01-20

Investigate the individual and contextual variables related to caries in underprivileged adolescents, and the disparity in distribution of the disease. Cross-sectional analytical study, conducted in the city of Piracicaba, SP, Brazil, in 2012. The probabilistic sample was composed of 1,179 adolescents from 15-19 years of age, randomly selected from 21 state schools and 34 Primary Health Units--Family Health (PHU-FH). The dependent variables studied were number of decayed teeth and caries experience (DMFT). The independent variables were classified into individual (clinical, sociodemographic, psychosocial, self-perception, impact on oral health, access to services, and quality of life) and contextual (social exclusion index, total number of residents in suburb, literacy rate, and the following variables given in percentages: residences in the home ownership category, provision of domestic sewerage, trash collection, families with income of over 1 minimum wage per month, and families without monthly income) variables. The multilevel regression model was estimated by the PROC GLIMMIX (Generalized Linear Models-Mixed) procedure, considering the individual variables as Level 1 and the contextual variables of the suburbs as Level 2. Adjustment of the model was evaluated by -2 Res Log Likelihood with α = 0.05. As regards the individual variables, adolescents who declared having a prison inmate in the Family and resided in homes with a larger number of persons, showed a higher number of decayed teeth. There were a larger number of decayed teeth, a higher DMFT value, and worse self-perception as regards the health of their teeth and mouth. Other variables, such as being of the female gender, age and time since last visit to the dentist were related to the DMFT index. As regards the contextual variables, the DMFT was lower in suburbs with greater access to domestic sewage, and the number of decayed teeth was higher in suburbs with the worst social exclusion indices

Contextual Approach with Guided Discovery Learning and Brain Based Learning in Geometry Learning

NASA Astrophysics Data System (ADS)

Kartikaningtyas, V.; Kusmayadi, T. A.; Riyadi

2017-09-01

The aim of this study was to combine the contextual approach with Guided Discovery Learning (GDL) and Brain Based Learning (BBL) in geometry learning of junior high school. Furthermore, this study analysed the effect of contextual approach with GDL and BBL in geometry learning. GDL-contextual and BBL-contextual was built from the steps of GDL and BBL that combined with the principles of contextual approach. To validate the models, it uses quasi experiment which used two experiment groups. The sample had been chosen by stratified cluster random sampling. The sample was 150 students of grade 8th in junior high school. The data were collected through the student’s mathematics achievement test that given after the treatment of each group. The data analysed by using one way ANOVA with different cell. The result shows that GDL-contextual has not different effect than BBL-contextual on mathematics achievement in geometry learning. It means both the two models could be used in mathematics learning as the innovative way in geometry learning.

Perceiving speech in context: Compensation for contextual variability during acoustic cue encoding and categorization

NASA Astrophysics Data System (ADS)

Toscano, Joseph Christopher

Several fundamental questions about speech perception concern how listeners understand spoken language despite considerable variability in speech sounds across different contexts (the problem of lack of invariance in speech). This contextual variability is caused by several factors, including differences between individual talkers' voices, variation in speaking rate, and effects of coarticulatory context. A number of models have been proposed to describe how the speech system handles differences across contexts. Critically, these models make different predictions about (1) whether contextual variability is handled at the level of acoustic cue encoding or categorization, (2) whether it is driven by feedback from category-level processes or interactions between cues, and (3) whether listeners discard fine-grained acoustic information to compensate for contextual variability. Separating the effects of cue- and category-level processing has been difficult because behavioral measures tap processes that occur well after initial cue encoding and are influenced by task demands and linguistic information. Recently, we have used the event-related brain potential (ERP) technique to examine cue encoding and online categorization. Specifically, we have looked at differences in the auditory N1 as a measure of acoustic cue encoding and the P3 as a measure of categorization. This allows us to examine multiple levels of processing during speech perception and can provide a useful tool for studying effects of contextual variability. Here, I apply this approach to determine the point in processing at which context has an effect on speech perception and to examine whether acoustic cues are encoded continuously. Several types of contextual variability (talker gender, speaking rate, and coarticulation), as well as several acoustic cues (voice onset time, formant frequencies, and bandwidths), are examined in a series of experiments. The results suggest that (1) at early stages of speech

Contextualizing immigrant access to health resources.

PubMed

Yang, Joshua S

2010-06-01

A vast majority of our understanding of immigrant health centers around traits of individuals and groups. While useful, current approaches to research on immigrant health decontextualize the experience of immigrants in the United States. This paper uses a historical case study of the Chinese community in San Francisco to develop a contextual framework to understand the levels of influence that impact the availability of health resources in immigrant communities. International, transnational, transcommunity, and enclave contexts have shaped health care access for Chinese immigrants in San Francisco. The conceptual framework provides a basis for future research, programmatic, and policy work that integrates individual and contextual factors in assessing and improving immigrant access to health resources.

Familial Alzheimer A2 V mutation reduces the intrinsic disorder and completely changes the free energy landscape of the Aβ1-28 monomer.

PubMed

Nguyen, Phuong H; Tarus, Bogdan; Derreumaux, Philippe

2014-01-16

The self-assembly of the amyloid-β (Aβ) peptide of 39-43 amino acids into senile plaques is one hallmark of Alzheimer's disease (AD) pathology. While A2 V carriers remain healthy in the heterozygous state, they suffer from early onset AD in the homozygous state. As a first toward understanding the impact of A2 V on Aβ at its earlier stage, we characterized the equilibrium ensemble of the Aβ1-28 wild type and Aβ1-28 A2 V monomers by means of extensive atomistic replica exchange molecular dynamics simulations. While global conformational properties such as the radius of gyration and the average secondary structure content of the whole peptides are very similar, the population of β-hairpins is increased by a factor of 4 in A2 V, and this may explain the enhanced Aβ1-40 A2 V aggregation kinetics with respect to Aβ1-40 wild type. Both peptides display a non-negligible population of extended metastable conformations differing however in their atomic details that represent ideal seeds for polymerization. Remarkably, upon A2 V mutation, the intrinsic disorder of Aβ1-28 monomer is reduced by a factor of 2, and the free energy landscape is completely different. This difference in the conformational ensembles of the two peptides may explain in part why the mixture of the Aβ40 WT and A2 V peptides protects against AD.

Prenatal choline supplementation increases sensitivity to contextual processing of temporal information

PubMed Central

Buhusi, Catalin V.; Lamoureux, Jeffrey A.; Meck, Warren H.

2008-01-01

The effects of prenatal choline availability on contextual processing in a 30-s peak-interval (PI) procedure with gaps (1, 5, 10, and 15 s) were assessed in adult male rats. Neither supplementation nor deprivation of prenatal choline affected baseline timing performance in the PI procedure. However, prenatal choline availability significantly altered the contextual processing of gaps inserted into the to-be-timed signal (light on). Choline-supplemented rats displayed a high degree of context sensitivity as indicated by clock resetting when presented with a gap in the signal (light off). In contrast, choline-deficient rats showed no such effect and stopped their clocks during the gap. Control rats exhibited an intermediate level of contextual processing in between stop and full reset. When switched to a reversed gap condition in which rats timed the absence of the light and the presence of the light served as a gap, all groups reset their clocks following a gap. Furthermore, when filling the intertrial interval (ITI) with a distinctive stimulus (e.g., sound), both choline-supplemented and control rats rightward shifted their PI functions less on trials with gaps than choline-deficient rats, indicating greater contextual sensitivity and reduced clock resetting under these conditions. Overall, these data support the view that prenatal choline availability affects the sensitivity to the context in which gaps are inserted in the to-be-timed signal, thereby influencing whether rats run, stop, or reset their clocks. PMID:18778696

THE DEVELOPMENT OF A CLASSIFICATION SCHEME OF CONTEXTUAL AIDS.

ERIC Educational Resources Information Center

AMES, WILBUR S.

A STUDY WAS CONDUCTED TO DETERMINE FROM THE VERBAL RESPONSES OF READERS THE TYPES OF CONTEXTUAL AIDS THAT SERVE AS CLUES TO THE MEANINGS THAT MIGHT BE ATTACHED TO SIMULATED WORDS AND TO CLASSIFY THESE CONTEXTUAL AIDS ON THE BASIS OF THE ELEMENTS OF THE VERBAL CONTEXT THAT WAS UTILIZED BY THE READER. AN INTROSPECTIVE TECHNIQUE WAS USED IN…

Why Contextual Preference Reversals Maximize Expected Value

PubMed Central

2016-01-01

Contextual preference reversals occur when a preference for one option over another is reversed by the addition of further options. It has been argued that the occurrence of preference reversals in human behavior shows that people violate the axioms of rational choice and that people are not, therefore, expected value maximizers. In contrast, we demonstrate that if a person is only able to make noisy calculations of expected value and noisy observations of the ordinal relations among option features, then the expected value maximizing choice is influenced by the addition of new options and does give rise to apparent preference reversals. We explore the implications of expected value maximizing choice, conditioned on noisy observations, for a range of contextual preference reversal types—including attraction, compromise, similarity, and phantom effects. These preference reversal types have played a key role in the development of models of human choice. We conclude that experiments demonstrating contextual preference reversals are not evidence for irrationality. They are, however, a consequence of expected value maximization given noisy observations. PMID:27337391

Contextuality supplies the 'magic' for quantum computation.

PubMed

Howard, Mark; Wallman, Joel; Veitch, Victor; Emerson, Joseph

2014-06-19

Quantum computers promise dramatic advantages over their classical counterparts, but the source of the power in quantum computing has remained elusive. Here we prove a remarkable equivalence between the onset of contextuality and the possibility of universal quantum computation via 'magic state' distillation, which is the leading model for experimentally realizing a fault-tolerant quantum computer. This is a conceptually satisfying link, because contextuality, which precludes a simple 'hidden variable' model of quantum mechanics, provides one of the fundamental characterizations of uniquely quantum phenomena. Furthermore, this connection suggests a unifying paradigm for the resources of quantum information: the non-locality of quantum theory is a particular kind of contextuality, and non-locality is already known to be a critical resource for achieving advantages with quantum communication. In addition to clarifying these fundamental issues, this work advances the resource framework for quantum computation, which has a number of practical applications, such as characterizing the efficiency and trade-offs between distinct theoretical and experimental schemes for achieving robust quantum computation, and putting bounds on the overhead cost for the classical simulation of quantum algorithms.

On the role of working memory in spatial contextual cueing.

PubMed

Travis, Susan L; Mattingley, Jason B; Dux, Paul E

2013-01-01

The human visual system receives more information than can be consciously processed. To overcome this capacity limit, we employ attentional mechanisms to prioritize task-relevant (target) information over less relevant (distractor) information. Regularities in the environment can facilitate the allocation of attention, as demonstrated by the spatial contextual cueing paradigm. When observers are exposed repeatedly to a scene and invariant distractor information, learning from earlier exposures enhances the search for the target. Here, we investigated whether spatial contextual cueing draws on spatial working memory resources and, if so, at what level of processing working memory load has its effect. Participants performed 2 tasks concurrently: a visual search task, in which the spatial configuration of some search arrays occasionally repeated, and a spatial working memory task. Increases in working memory load significantly impaired contextual learning. These findings indicate that spatial contextual cueing utilizes working memory resources.

Subacute casemix classification for stroke rehabilitation in Australia. How well does AN-SNAP v2 explain variance in outcomes?

PubMed

Kohler, Friedbert; Renton, Roger; Dickson, Hugh G; Estell, John; Connolly, Carol E

2011-02-01

We sought the best predictors for length of stay, discharge destination and functional improvement for inpatients undergoing rehabilitation following a stroke and compared these predictors against AN-SNAP v2. The Oxfordshire classification subgroup, sociodemographic data and functional data were collected for patients admitted between 1997 and 2007, with a diagnosis of recent stroke. The data were factor analysed using Principal Components Analysis for categorical data (CATPCA). Categorical regression analyses was performed to determine the best predictors of length of stay, discharge destination, and functional improvement. A total of 1154 patients were included in the study. Principal components analysis indicated that the data were effectively unidimensional, with length of stay being the most important component. Regression analysis demonstrated that the best predictor was the admission motor FIM score, explaining 38.9% of variance for length of stay, 37.4%.of variance for functional improvement and 16% of variance for discharge destination. The best explanatory variable in our inpatient rehabilitation service is the admission motor FIM. AN- SNAP v2 classification is a less effective explanatory variable. This needs to be taken into account when using AN-SNAP v2 classification for clinical or funding purposes.

Differential effects of cannabinoid receptor agonist on social discrimination and contextual fear in amygdala and hippocampus.

PubMed

Segev, Amir; Akirav, Irit

2011-04-01

We examined whether the cannabinoid receptor agonist WIN55,212-2 (WIN; 5 µg/side) microinjected into the hippocampus or the amygdala would differentially affect memory processes in a neutral vs. an aversive task. In the aversive contextual fear task, WIN into the basolateral amygdala impaired fear acquisition/consolidation, but not retrieval. In the ventral subiculum (vSub), WIN impaired fear retrieval. In the neutral social discrimination task, WIN into the vSub impaired both acquisition/consolidation and retrieval, whereas in the medial amygdala WIN impaired acquisition. The results suggest that cannabinoid signaling differentially affects memory in a task-, region-, and memory stage-dependent manner.

A model explaining neutrino masses and the DAMPE cosmic ray electron excess

NASA Astrophysics Data System (ADS)

Fan, Yi-Zhong; Huang, Wei-Chih; Spinrath, Martin; Tsai, Yue-Lin Sming; Yuan, Qiang

2018-06-01

We propose a flavored U(1)eμ neutrino mass and dark matter (DM) model to explain the recent DArk Matter Particle Explorer (DAMPE) data, which feature an excess on the cosmic ray electron plus positron flux around 1.4 TeV. Only the first two lepton generations of the Standard Model are charged under the new U(1)eμ gauge symmetry. A vector-like fermion ψ, which is our DM candidate, annihilates into e± and μ± via the new gauge boson Z‧ exchange and accounts for the DAMPE excess. We have found that the data favors a ψ mass around 1.5 TeV and a Z‧ mass around 2.6 TeV, which can potentially be probed by the next generation lepton colliders and DM direct detection experiments.

Contextual Learning in Adult Education. Practice Application Brief No. 12.

ERIC Educational Resources Information Center

Imel, Susan

Contextual learning is rooted in a constructivist approach to teaching and learning. According to constructivist theory, individuals learn by constructing meaning through interacting with and interpreting their environments. Current perspectives on what it means for learning to be contextualized include the following: situated cognition, social…

Focal Event, Contextualization, and Effective Communication in the Mathematics Classroom

ERIC Educational Resources Information Center

Nilsson, Per; Ryve, Andreas

2010-01-01

The aim of this article is to develop analytical tools for studying mathematical communication in collaborative activities. The theoretical construct of contextualization is elaborated methodologically in order to study diversity in individual thinking in relation to effective communication. The construct of contextualization highlights issues of…

Individual and contextual factors influencing dental health care utilization by preschool children: a multilevel analysis

PubMed

Piovesan, Chaiana; Ardenghi, Thiago Machado; Mendes, Fausto Medeiros; Agostini, Bernardo Antonio; Michel-Crosato, Edgard

2017-03-30

The effect of contextual factors on dental care utilization was evaluated after adjustment for individual characteristics of Brazilian preschool children. This cross-sectional study assessed 639 preschool children aged 1 to 5 years from Santa Maria, a town in Rio Grande do Sul State, located in southern Brazil. Participants were randomly selected from children attending the National Children's Vaccination Day and 15 health centers were selected for this research. Visual examinations followed the ICDAS criteria. Parents answered a questionnaire about demographic and socioeconomic characteristics. Contextual influences on children's dental care utilization were obtained from two community-related variables: presence of dentists and presence of workers' associations in the neighborhood. Unadjusted and adjusted multilevel logistic regression models were used to describe the association between outcome and predictor variables. A prevalence of 21.6% was found for regular use of dental services. The unadjusted assessment of the associations of dental health care utilization with individual and contextual factors included children's ages, family income, parents' schooling, mothers' participation in their children's school activities, dental caries, and presence of workers' associations in the neighborhood as the main outcome covariates. Individual variables remained associated with the outcome after adding contextual variables in the model. In conclusion, individual and contextual variables were associated with dental health care utilization by preschool children.

Pigeons Exhibit Contextual Cueing to Both Simple and Complex Backgrounds

PubMed Central

Wasserman, Edward A.; Teng, Yuejia; Castro, Leyre

2014-01-01

Repeated pairings of a particular visual context with a specific location of a target stimulus facilitate target search in humans. We explored an animal model of this contextual cueing effect using a novel Cueing-Miscueing design. Pigeons had to peck a target which could appear in one of four possible locations on four possible color backgrounds or four possible color photographs of real-world scenes. On 80% of the trials, each of the contexts was uniquely paired with one of the target locations; on the other 20% of the trials, each of the contexts was randomly paired with the remaining target locations. Pigeons came to exhibit robust contextual cueing when the context preceded the target by 2 s, with reaction times to the target being shorter on correctly-cued trials than on incorrectly-cued trials. Contextual cueing proved to be more robust with photographic backgrounds than with uniformly colored backgrounds. In addition, during the context-target delay, pigeons predominately pecked toward the location of the upcoming target, suggesting that attentional guidance contributes to contextual cueing. These findings confirm the effectiveness of animal models of contextual cueing and underscore the important part played by associative learning in producing the effect. PMID:24491468

Independence of long-term contextual memory and short-term perceptual hypotheses: Evidence from contextual cueing of interrupted search.

PubMed

Schlagbauer, Bernhard; Mink, Maurice; Müller, Hermann J; Geyer, Thomas

2017-02-01

Observers are able to resume an interrupted search trial faster relative to responding to a new, unseen display. This finding of rapid resumption is attributed to short-term perceptual hypotheses generated on the current look and confirmed upon subsequent looks at the same display. It has been suggested that the contents of perceptual hypotheses are similar to those of other forms of memory acquired long-term through repeated exposure to the same search displays over the course of several trials, that is, the memory supporting "contextual cueing." In three experiments, we investigated the relationship between short-term perceptual hypotheses and long-term contextual memory. The results indicated that long-term, contextual memory of repeated displays neither affected the generation nor the confirmation of short-term perceptual hypotheses for these displays. Furthermore, the analysis of eye movements suggests that long-term memory provides an initial benefit in guiding attention to the target, whereas in subsequent looks guidance is entirely based on short-term perceptual hypotheses. Overall, the results reveal a picture of both long- and short-term memory contributing to reliable performance gains in interrupted search, while exerting their effects in an independent manner.

E&V Guidebook, Version 1.1

DTIC Science & Technology

1989-08-15

checklist 14.1] Chapter 3, Language-related issues, extracts from the Ada language reference manua! [,_D 1982] those features exp!icitly a!owcd to vay...welcome. Please send comments electronically (preferred) to szymansk~aja;po.sei.cmu.edu, or by regular mail to Mr. Raymond Szymanski , AFWAL/AAAF, Wright...of Tool Features for the Ada Programming Support Environment (APSE) 4-3 4.3 E&V Report: DoD APSE Analysis 4-4 4.4 Classification Schema/E&V Taxonomy

The Swift/Fermi GRB 080928 from 1 eV to 150 keV

NASA Technical Reports Server (NTRS)

Sonbas, Eda; Rossi, A.; Schulze, S.; Klose, S.; Kann, D. A.; Ferrero, P.; NicuesaGuelbenzu, A.; Rau, A.; Kruehler, T.; Greiner, J.;

Bupropion Dose-Dependently Reverses Nicotine Withdrawal Deficits in Contextual Fear Conditioning

PubMed Central

Portugal, George S.; Gould, Thomas J.

2007-01-01

Bupropion, a norepinephrine and dopamine reuptake inhibitor and nicotinic acetylcholine receptor antagonist, facilitates smoking cessation and reduces some symptoms of nicotine withdrawal. However, the effects of bupropion on nicotine withdrawal-associated deficits in learning remain unclear. The present study investigated whether bupropion has effects on contextual and cued fear conditioning following withdrawal from chronic nicotine or when administered alone. Bupropion was administered alone for a range of doses (2.5, 5, 10, 20 or 40 mg/kg), and dose-dependent impairments in contextual and cued fear conditioning were observed (20 or 40 mg/kg). Follow-up studies investigated if bupropion disrupted acquisition or expression of fear conditioning. Bupropion (40 mg/kg) administration on training day only produced deficits in contextual fear conditioning. Alternatively, bupropion (20 or 40 mg/kg) administration during testing dose-dependently produced deficits in contextual and cued fear conditioning. To test the effect of bupropion on nicotine withdrawal, mice were withdrawn from 12 days of chronic nicotine (6.3 mg/kg/day) or saline treatment. Withdrawal from chronic nicotine disrupted contextual fear conditioning; however, 5 mg/kg bupropion reversed this deficit. Overall, these results indicate that a low dose of bupropion can reverse nicotine withdrawal deficits in contextual fear conditioning, but that high doses of bupropion produce deficits in fear conditioning. PMID:17868796

Contextual view showing west elevations of building H81 on right ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Contextual view showing west elevations of building H81 on right and H1 in middle; camera facing northeast. - Mare Island Naval Shipyard, Hospital Headquarters, Johnson Lane, west side at intersection of Johnson Lane & Cossey Street, Vallejo, Solano County, CA

Survival of the Partial Reinforcement Extinction Effect after Contextual Shifts

ERIC Educational Resources Information Center

Boughner, Robert L.; Papini, Mauricio R.

2006-01-01

The effects of contextual shifts on the partial reinforcement extinction effect (PREE) were studied in autoshaping with rats. Experiment 1 established that the two contexts used subsequently were easily discriminable and equally salient. In Experiment 2, independent groups of rats received acquisition training under partial reinforcement (PRF) or…

Enhance placebo, avoid nocebo: How contextual factors affect physiotherapy outcomes.

PubMed

Testa, Marco; Rossettini, Giacomo

2016-08-01

Placebo and nocebo represent complex and distinct psychoneurobiological phenomena in which behavioural and neurophysiological modifications occur together with the application of a treatment. Despite a better understanding of this topic in the medical field, little is known about their role in physiotherapy. The aim of this review is: a) to elucidate the neurobiology behind placebo and nocebo effects, b) to describe the role of the contextual factors as modulators of the clinical outcomes in rehabilitation and c) to provide clinical and research guidelines on their uses. The physiotherapist's features, the patient's features, the patient-physiotherapist relationship, the characteristics of the treatment and the overall healthcare setting are all contextual factors influencing clinical outcomes. Since every physiotherapy treatment determines a specific and a contextual effect, physiotherapists should manage the contextual factors as a boosting element of any manual therapy to improve placebo effects and avoid detrimental nocebo effects. Copyright © 2016 Elsevier Ltd. All rights reserved.

Exploring the role of contextual information in bloodstain pattern analysis: A qualitative approach.

PubMed

Osborne, Nikola K P; Taylor, Michael C; Zajac, Rachel

2016-03-01

During Bloodstain Pattern Analysis (BPA), an analyst may encounter various sources of contextual information. Although contextual bias has emerged as a valid concern for the discipline, little is understood about how contextual information informs BPA. To address this issue, we asked 15 experienced bloodstain pattern analysts from New Zealand and Australia to think aloud as they classified bloodstain patterns from two homicide cases. Analysts could request items of contextual information, and were required to state how each item would inform their analysis. Pathology reports and additional photographs of the scene were the most commonly requested items of information. We coded analysts' reasons for requesting contextual information--and the way in which they integrated this information--according to thematic analysis. We identified considerable variation in both of these variables, raising important questions about the role and necessity of contextual information in decisions about bloodstain pattern evidence. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Developmental trajectory of contextual learning and 24-h acetylcholine release in the hippocampus

PubMed Central

Takase, Kenkichi; Sakimoto, Yuya; Kimura, Fukuko; Mitsushima, Dai

2014-01-01

To determine the developmental trajectory of hippocampal function in rats, we examined 24-h changes in extracellular acetylcholine (ACh) levels and contextual learning performance. Extracellular ACh significantly correlated with spontaneous behavior, exhibiting a 24-h rhythm in juvenile (4-week-old), pubertal (6-week-old), and adult (9- to 12-week-old) rats. Although juveniles of both sexes exhibited low ACh levels, adult males had higher ACh levels than adult females. Moreover, juveniles exhibited much more spontaneous activity than adults when they showed equivalent ACh levels. Similarly, juveniles of both sexes exhibited relatively low contextual learning performance. Because contextual learning performance was significantly increased only in males, adult males exhibited better performance than adult females. We also observed a developmental relationship between contextual learning and ACh levels. Scopolamine pretreatment blocked contextual learning and interrupted the correlation. Since long-term scopolamine treatment after weaning impaired contextual learning in juveniles, the cholinergic input may participate in the development of hippocampus. PMID:24435246

Contextual priming in semantic anomia: a case study.

PubMed

Renvall, Kati; Laine, Matti; Martin, Nadine

2005-11-01

The present case continues the series of anomia treatment studies with contextual priming (CP), being the second in-depth treatment study conducted for an individual suffering from semantically based anomia. Our aim was to acquire further evidence of the facilitation and interference effects of the CP treatment on semantic anomia. Based on the results of the study of , our hypothesis before the treatment was that our participant would show short-term interference and at most modest and short-term benefit from treatment. To acquire such evidence would not only be important for the choice of anomia treatment methods in individual patients, but would also prompt further development of the CP method. The CP technique used for our participant included cycles of repeating and naming items in three contextual conditions (semantic, phonological, and unrelated). As predicted, the overall improvement of naming was modest and short-term. Interestingly, the contextual condition that corresponded with the nature of our patient's underlying naming deficit (semantic) elicited immediate interference in the form of contextual naming errors, as well as short-term improvement of naming. Based on this and a recent study by , it appears that despite short-term positive effects, in its current form the CP treatment is not sufficient for those aphasics who have a semantic deficit underlying their anomia. The possible mechanism and directions for future research are discussed.

Contextual consistency facilitates long-term memory of perceptual detail in barely seen images.

PubMed

Gronau, Nurit; Shachar, Meytal

2015-08-01

It is long known that contextual information affects memory for an object's identity (e.g., its basic level category), yet it is unclear whether schematic knowledge additionally enhances memory for the precise visual appearance of an item. Here we investigated memory for visual detail of merely glimpsed objects. Participants viewed pairs of contextually related and unrelated stimuli, presented for an extremely brief duration (24 ms, masked). They then performed a forced-choice memory-recognition test for the precise perceptual appearance of 1 of 2 objects within each pair (i.e., the "memory-target" item). In 3 experiments, we show that memory-target stimuli originally appearing within contextually related pairs are remembered better than targets appearing within unrelated pairs. These effects are obtained whether the target is presented at test with its counterpart pair object (i.e., when reiterating the original context at encoding) or whether the target is presented alone, implying that the contextual consistency effects are mediated predominantly by processes occurring during stimulus encoding, rather than during stimulus retrieval. Furthermore, visual detail encoding is improved whether object relations involve implied action or not, suggesting that, contrary to some prior suggestions, action is not a necessary component for object-to-object associative "grouping" processes. Our findings suggest that during a brief glimpse, but not under long viewing conditions, contextual associations may play a critical role in reducing stimulus competition for attention selection and in facilitating rapid encoding of sensory details. Theoretical implications with respect to classic frame theories are discussed. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Exploration of Opinion-aware Approach to Contextual Suggestion

DTIC Science & Technology

2014-11-01

effectiveness of the proposed method. 1 Introduction TREC 1014 Contextual Suggestion Track gives researchers the chance to test their methods on providing...each category. Information including the name, average rating, address, business hour, all ratings and the associated text reviews of the candidate...Annals of Statistics , 29:1189–1232, 2000. 5. K. Ganesan, C. Zhai, and J. Han. Opinosis: a graph-based approach to abstractive summarization of highly

Contextual information management: An example of independent-checking in the review of laboratory-based bloodstain pattern analysis.

PubMed

Osborne, Nikola K P; Taylor, Michael C

2018-05-01

This article describes a New Zealand forensic agency's contextual information management protocol for bloodstain pattern evidence examined in the laboratory. In an effort to create a protocol that would have minimal impact on current work-flow, while still effectively removing task-irrelevant contextual information, the protocol was designed following an in-depth consultation with management and forensic staff. The resulting design was for a protocol of independent-checking (i.e. blind peer-review) where the checker's interpretation of the evidence is conducted in the absence of case information and the original examiner's notes or interpretation(s). At the conclusion of a ten-case trial period, there was widespread agreement that the protocol had minimal impact on the number of people required, the cost, or the time to complete an item examination. The agency is now looking to adopt the protocol into standard operating procedures and in some cases the protocol has been extended to cover other laboratory-based examinations (e.g. fabric damage, shoeprint examination, and physical fits). The protocol developed during this trial provides a useful example for agencies seeking to adopt contextual information management into their workflow. Copyright © 2018 The Chartered Society of Forensic Sciences. Published by Elsevier B.V. All rights reserved.

The acquisition of contextual cueing effects by persons with and without intellectual disability.

PubMed

Merrill, Edward C; Conners, Frances A; Yang, Yingying; Weathington, Dana

2014-10-01

Two experiments were conducted to compare the acquisition of contextual cueing effects of adolescents and young adults with intellectual disabilities (ID) relative to typically developing children and young adults. Contextual cueing reflects an implicit, memory based attention guidance mechanism that results in faster search for target locations that have been previously experienced in a predictable context. In the study, participants located a target stimulus embedded in a context of numerous distracter stimuli. During a learning phase, the location of the target was predictable from the location of the distracters in the search displays. We then compared response times to locating predictable relative to unpredictable targets presented in a test phase. In Experiment 1, all of the distracters predicted the location of the target. In Experiment 2, half of the distracters predicted the location of the target while the other half varied randomly. The participants with ID exhibited significant contextual facilitation in both experiments, with the magnitude of facilitation being similar to that of the typically developing (TD) children and adults. We concluded that deficiencies in contextual cueing are not necessarily associated with low measured intelligence that results in a classification of ID. Copyright © 2014 Elsevier Ltd. All rights reserved.

Optimal Jet Finder (v1.0 C++)

NASA Astrophysics Data System (ADS)

Chumakov, S.; Jankowski, E.; Tkachov, F. V.

2006-10-01

We describe a C++ implementation of the Optimal Jet Definition for identification of jets in hadronic final states of particle collisions. We explain interface subroutines and provide a usage example. The source code is available from http://www.inr.ac.ru/~ftkachov/projects/jets/. Program summaryTitle of program: Optimal Jet Finder (v1.0 C++) Catalogue identifier: ADSB_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADSB_v2_0 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer: any computer with a standard C++ compiler Tested with:GNU gcc 3.4.2, Linux Fedora Core 3, Intel i686; Forte Developer 7 C++ 5.4, SunOS 5.9, UltraSPARC III+; Microsoft Visual C++ Toolkit 2003 (compiler 13.10.3077, linker 7.10.30777, option /EHsc), Windows XP, Intel i686. Programming language used: C++ Memory required:˜1 MB (or more, depending on the settings) No. of lines in distributed program, including test data, etc.: 3047 No. of bytes in distributed program, including test data, etc.: 17 884 Distribution format: tar.gz Nature of physical problem: Analysis of hadronic final states in high energy particle collision experiments often involves identification of hadronic jets. A large number of hadrons detected in the calorimeter is reduced to a few jets by means of a jet finding algorithm. The jets are used in further analysis which would be difficult or impossible when applied directly to the hadrons. Grigoriev et al. [D.Yu. Grigoriev, E. Jankowski, F.V. Tkachov, Phys. Rev. Lett. 91 (2003) 061801] provide brief introduction to the subject of jet finding algorithms and a general review of the physics of jets can be found in [R. Barlow, Rep. Prog. Phys. 36 (1993) 1067]. Method of solution: The software we provide is an implementation of the so-called Optimal Jet Definition (OJD). The theory of OJD was developed in [F.V. Tkachov, Phys. Rev. Lett. 73 (1994) 2405; Erratum, Phys. Rev. Lett. 74 (1995) 2618; F.V. Tkachov, Int. J. Modern Phys

Memory consolidation and contextual interference effects with computer games.

PubMed

Shewokis, Patricia A

2003-10-01

Some investigators of the contextual interference effect contend that there is a direct relation between the amount of practice and the contextual interference effect based on the prediction that the improvement in learning tasks in a random practice schedule, compared to a blocked practice schedule, increases in magnitude as the amount of practice during acquisition on the tasks increases. Research using computer games in contextual interference studies has yielded a large effect (f = .50) with a random practice schedule advantage during transfer. These investigations had a total of 36 and 72 acquisition trials, respectively. The present study tested this prediction by having 72 college students, who were randomly assigned to a blocked or random practice schedule, practice 102 trials of three computer-game tasks across three days. After a 24-hr. interval, 6 retention and 5 transfer trials were performed. Dependent variables were time to complete an event in seconds and number of errors. No significant differences were found for retention and transfer. These results are discussed in terms of how the amount of practice, task-related factors, and memory consolidation mediate the contextual interference effect.

The Contextualized Technology Adaptation Process (CTAP): Optimizing Health Information Technology to Improve Mental Health Systems.

PubMed

Lyon, Aaron R; Wasse, Jessica Knaster; Ludwig, Kristy; Zachry, Mark; Bruns, Eric J; Unützer, Jürgen; McCauley, Elizabeth

2016-05-01

Health information technologies have become a central fixture in the mental healthcare landscape, but few frameworks exist to guide their adaptation to novel settings. This paper introduces the contextualized technology adaptation process (CTAP) and presents data collected during Phase 1 of its application to measurement feedback system development in school mental health. The CTAP is built on models of human-centered design and implementation science and incorporates repeated mixed methods assessments to guide the design of technologies to ensure high compatibility with a destination setting. CTAP phases include: (1) Contextual evaluation, (2) Evaluation of the unadapted technology, (3) Trialing and evaluation of the adapted technology, (4) Refinement and larger-scale implementation, and (5) Sustainment through ongoing evaluation and system revision. Qualitative findings from school-based practitioner focus groups are presented, which provided information for CTAP Phase 1, contextual evaluation, surrounding education sector clinicians' workflows, types of technologies currently available, and influences on technology use. Discussion focuses on how findings will inform subsequent CTAP phases, as well as their implications for future technology adaptation across content domains and service sectors.

Contextual Stress and Health Risk Behaviors among African American Adolescents

ERIC Educational Resources Information Center

Copeland-Linder, Nikeea; Lambert, Sharon F.; Chen, Yi-Fu; Ialongo, Nicholas S.

2011-01-01

This study examined the longitudinal association between contextual stress and health risk behaviors and the role of protective factors in a community epidemiologically-defined sample of urban African American adolescents (N = 500; 46.4% female). Structural equation modeling was used to create a latent variable measuring contextual stress…

A Contextual Behavior Science Framework for Understanding How Behavioral Flexibility Relates to Anxiety.

PubMed

Palm Reed, Kathleen M; Cameron, Amy Y; Ameral, Victoria E

2017-09-01

There is a growing literature focusing on the emerging idea that behavioral flexibility, rather than particular emotion regulation strategies per se, provides greater promise in predicting and influencing anxiety-related psychopathology. Yet this line of research and theoretical analysis appear to be plagued by its own challenges. For example, middle-level constructs, such as behavioral flexibility, are difficult to define, difficult to measure, and difficult to interpret in relation to clinical interventions. A key point that some researchers have made is that previous studies examining flexible use of emotion regulation strategies (or, more broadly, coping) have failed due to a lack of focus on context. That is, examining strategies in isolation of the context in which they are used provides limited information on the suitability, rigid adherence, or effectiveness of a given strategy in that situation. Several of these researchers have proposed the development of new models to define and measure various types of behavioral flexibility. We would like to suggest that an explanation of the phenomenon already exists and that we can go back to our behavioral roots to understand this phenomenon rather than focusing on defining and capturing a new process. Indeed, thorough contextual behavioral analyses already yield a useful account of what has been observed. We will articulate a model explaining behavioral flexibility using a functional, contextual framework, with anxiety-related disorders as an example.

Time to Guide: Evidence for Delayed Attentional Guidance in Contextual Cueing

PubMed Central

Kunar, Melina A.; Flusberg, Stephen J.; Wolfe, Jeremy M.

2008-01-01

Contextual cueing experiments show that, when displays are repeated, reaction times (RTs) to find a target decrease over time even when the observers are not aware of the repetition. Recent evidence suggests that this benefit in standard contextual cueing tasks is not likely to be due to an improvement in attentional guidance (Kunar, Flusberg, Horowitz & Wolfe, 2007). Nevertheless, we ask whether guidance can help participants find the target in a repeated display, if they are given sufficient time to encode the display. In Experiment 1 we increased the display complexity so that it took participants longer to find the target. Here we found a larger effect of guidance than in a condition with shorter RTs. Experiment 2 gave participants prior exposure to the display context. The data again showed that with more time participants could implement guidance to help find the target, provided that there was something in the search stimuli locations to guide attention to. The data suggest that although the benefit in a standard contextual cueing task is unlikely to be a result of guidance, guidance can play a role if it is given time to develop. PMID:18846248

Time to Guide: Evidence for Delayed Attentional Guidance in Contextual Cueing.

PubMed

Kunar, Melina A; Flusberg, Stephen J; Wolfe, Jeremy M

2008-01-01

Contextual cueing experiments show that, when displays are repeated, reaction times (RTs) to find a target decrease over time even when the observers are not aware of the repetition. Recent evidence suggests that this benefit in standard contextual cueing tasks is not likely to be due to an improvement in attentional guidance (Kunar, Flusberg, Horowitz & Wolfe, 2007). Nevertheless, we ask whether guidance can help participants find the target in a repeated display, if they are given sufficient time to encode the display. In Experiment 1 we increased the display complexity so that it took participants longer to find the target. Here we found a larger effect of guidance than in a condition with shorter RTs. Experiment 2 gave participants prior exposure to the display context. The data again showed that with more time participants could implement guidance to help find the target, provided that there was something in the search stimuli locations to guide attention to. The data suggest that although the benefit in a standard contextual cueing task is unlikely to be a result of guidance, guidance can play a role if it is given time to develop.

Featural and temporal attention selectively enhance task-appropriate representations in human V1

PubMed Central

Warren, Scott; Yacoub, Essa; Ghose, Geoffrey

2015-01-01

Our perceptions are often shaped by focusing our attention toward specific features or periods of time irrespective of location. We explore the physiological bases of these non-spatial forms of attention by imaging brain activity while subjects perform a challenging change detection task. The task employs a continuously varying visual stimulus that, for any moment in time, selectively activates functionally distinct subpopulations of primary visual cortex (V1) neurons. When subjects are cued to the timing and nature of the change, the mapping of orientation preference across V1 was systematically shifts toward the cued stimulus just prior to its appearance. A simple linear model can explain this shift: attentional changes are selectively targeted toward neural subpopulations representing the attended feature at the times the feature was anticipated. Our results suggest that featural attention is mediated by a linear change in the responses of task-appropriate neurons across cortex during appropriate periods of time. PMID:25501983

The Application of Contextual Approach in Learning Mathematics to Improve Students Motivation at SMPN 1 Kupang

ERIC Educational Resources Information Center

Ekowati, Ch. Krisnandari; Darwis, Muhammad; Upa, H. M. D. Pua; Tahmir, Suradi

2015-01-01

This research is an action research which aims to implement contextual teaching and learning (CTL) approach to learn mathematics, focus on the integration subjects. The approach utilizes the use of mathematics manipulative so that students can understand a mathematical concept to construct their own. The method which used in this research are…

Suffering: toward a contextual praxis.

PubMed

Georges, Jane M

2002-09-01

Janice M. Morse's article in Advances in Nursing Science (24:1) revised and summarized the major findings of a research program exploring the behavioral-experiential nature of suffering. Using a feminist critical theory stance, this article addresses Morse's conceptualization of a praxis of suffering. First, it identifies the strengths and contributions of Morse's body of research to nursing science. Next, it undertakes a critique situated in feminist critical theory in which the limitations of Morse's work are explored using exemplars from the Western literary tradition. Finally, the article proposes a new conceptualization of an alternative contextual praxis of suffering in which nurses' responses to suffering are situated in an emancipatory paradigm of authentic presence.

Temporal effect of manipulating NeuroD1 expression with the synthetic small molecule KHS101 on morphine contextual memory.

PubMed

Zhang, Yue; Kibaly, Cherkaouia; Xu, Chi; Loh, Horace H; Law, Ping-Yee

2017-11-01

The treatment of opioid addiction is challenging because addicts are highly prone to relapse when the memory of the former drug experience is triggered by emotional or environmental cues. An emerging and promising concept in addiction biology is that by manipulating adult hippocampal neurogenesis, a phenomenon involved in learning and memory, drug reward-like behaviors and relapse can be attenuated. We tested a new synthetic compound, KHS101, in an animal model of drug-associated contextual memory. KHS101 has been reported to increase the expression of neurogenic differentiation 1 (NeuroD1), a transcription factor involved in adult neurogenesis, and to specifically induce neuronal differentiation both in vitro and in vivo. Our results indicated that the subcutaneous injection of 3 mg/kg KHS101 for 7 days before conditioned place preference (CPP) training prolonged CPP extinction, while the same treatment after training accelerated extinction. This effect paralleled that observed following temporally controlled, tetracycline-induced NeuroD1 overexpression. Furthermore, the effect of KHS101 may occur via its induction of NeuroD1 expression as demonstrated by the abolition of the KHS101-mediated modulation of morphine-induced CPP extinction after the stereotaxic injection of lentiviral NeuroD1 small interfering RNA into the dentate gyrus (DG) of the hippocampus. These results suggest that the KHS101-mediated modulation of neurogenesis at a critical stage of the conditioning or the extinction of an opioid-associated experience may disrupt the memory trace of the existing opioid-associated experience to facilitate the extinction of drug-associated contextual memory. This implies that KHS101 has therapeutic potential for the treatment of opioid addiction. Copyright © 2017 Elsevier Ltd. All rights reserved.

The neurochemical basis of the contextual interference effect.

PubMed

Chalavi, Sima; Pauwels, Lisa; Heise, Kirstin-Friederike; Zivari Adab, Hamed; Maes, Celine; Puts, Nicolaas A J; Edden, Richard A E; Swinnen, Stephan P

2018-06-01

Efficient practice organization maximizes learning outcome. Although randomization of practice as compared to blocked practice damages training performance, it boosts retention performance, an effect called contextual interference. Motor learning modulates the GABAergic (gamma-aminobutyric acid) system within the sensorimotor cortex (SM); however, it is unclear whether different practice regimes differentially modulate this system and whether this is impacted by aging. Young and older participants were trained on 3 variations of a visuomotor task over 3 days, following either blocked or random practice schedule and retested 6 days later. Using magnetic resonance spectroscopy, SM and occipital cortex GABA+ levels were measured before and after training during the first and last training days. We found that (1) behavioral data confirmed the contextual interference effects, (2) within-day occipital cortex GABA+ levels decreased in random and increased in blocked group. This effect was more pronounced in older adults; and (3) baseline SM GABA+ levels predicted initial performance. These findings indicate a differential modulation of GABA levels across practice groups that is amplified by aging. Copyright © 2018 Elsevier Inc. All rights reserved.

Consequences of Contextual Factors on Clinical Reasoning in Resident Physicians

ERIC Educational Resources Information Center

McBee, Elexis; Ratcliffe, Temple; Picho, Katherine; Artino, Anthony R., Jr.; Schuwirth, Lambert; Kelly, William; Masel, Jennifer; van der Vleuten, Cees; Durning, Steven J.

2015-01-01

Context specificity and the impact that contextual factors have on the complex process of clinical reasoning is poorly understood. Using situated cognition as the theoretical framework, our aim was to evaluate the verbalized clinical reasoning processes of resident physicians in order to describe what impact the presence of contextual factors have…

No effect of glucose administration in a novel contextual fear generalization protocol in rats

PubMed Central

Luyten, L; Schroyens, N; Luyck, K; Fanselow, M S; Beckers, T

2016-01-01

The excessive transfer of fear acquired for one particular context to similar situations has been implicated in the development and maintenance of anxiety disorders, such as post-traumatic stress disorder. Recent evidence suggests that glucose ingestion improves the retention of context conditioning. It has been speculated that glucose might exert that effect by ameliorating hippocampal functioning, and may hold promise as a therapeutic add-on in traumatized patients because improved retention of contextual fear could help to restrict its generalization. However, direct data regarding the effect of glucose on contextual generalization are lacking. Here, we introduce a new behavioral protocol to study such contextual fear generalization in rats. In adult Wistar rats, our procedure yields a gradient of generalization, with progressively less freezing when going from the original training context, over a perceptually similar generalization context, to a markedly dissimilar context. Moreover, we find a flattening of the gradient when the training-test interval is prolonged with 1 week. We next examine the effect of systemic glucose administration on contextual generalization with this novel procedure. Our data do not sustain generalization-reducing effects of glucose and question its applicability in traumatic situations. In summary, we have developed a replicable contextual generalization procedure for rats and demonstrate how it is a valuable tool to examine the neurobiological correlates and test pharmacological interventions pertaining to an important mechanism in the etiology of pathological anxiety. PMID:27676444

Cortical and subcortical connections of V1 and V2 in early postnatal macaque monkeys.

PubMed

Baldwin, Mary K L; Kaskan, Peter M; Zhang, Bin; Chino, Yuzo M; Kaas, Jon H

2012-02-15

Connections of primary (V1) and secondary (V2) visual areas were revealed in macaque monkeys ranging in age from 2 to 16 weeks by injecting small amounts of cholera toxin subunit B (CTB). Cortex was flattened and cut parallel to the surface to reveal injection sites, patterns of labeled cells, and patterns of cytochrome oxidase (CO) staining. Projections from the lateral geniculate nucleus and pulvinar to V1 were present at 4 weeks of age, as were pulvinar projections to thin and thick CO stripes in V2. Injections into V1 in 4- and 8-week-old monkeys labeled neurons in V2, V3, middle temporal area (MT), and dorsolateral area (DL)/V4. Within V1 and V2, labeled neurons were densely distributed around the injection sites, but formed patches at distances away from injection sites. Injections into V2 labeled neurons in V1, V3, DL/V4, and MT of monkeys 2-, 4-, and 8-weeks of age. Injections in thin stripes of V2 preferentially labeled neurons in other V2 thin stripes and neurons in the CO blob regions of V1. A likely thick stripe injection in V2 at 4 weeks of age labeled neurons around blobs. Most labeled neurons in V1 were in superficial cortical layers after V2 injections, and in deep layers of other areas. Although these features of adult V1 and V2 connectivity were in place as early as 2 postnatal weeks, labeled cells in V1 and V2 became more restricted to preferred CO compartments after 2 weeks of age. Copyright © 2011 Wiley-Liss, Inc.

The effect of brain based learning with contextual approach viewed from adversity quotient

NASA Astrophysics Data System (ADS)

Kartikaningtyas, V.; Kusmayadi, T. A.; Riyadi, R.

2018-05-01

The aim of this research was to find out the effect of Brain Based Learning (BBL) with contextual approach viewed from adversity quotient (AQ) on mathematics achievement. BBL-contextual is the model to optimize the brain in the new concept learning and real life problem solving by making the good environment. Adversity Quotient is the ability to response and faces the problems. In addition, it is also about how to turn the difficulties into chances. This AQ classified into quitters, campers, and climbers. The research method used in this research was quasi experiment by using 2x3 factorial designs. The sample was chosen by using stratified cluster random sampling. The instruments were test and questionnaire for the data of AQ. The results showed that (1) BBL-contextual is better than direct learning on mathematics achievement, (2) there is no significant difference between each types of AQ on mathematics achievement, and (3) there is no interaction between learning model and AQ on mathematics achievement.

Strain-Specific V3 and CD4 Binding Site Autologous HIV-1 Neutralizing Antibodies Select Neutralization-Resistant Viruses.

PubMed

Moody, M Anthony; Gao, Feng; Gurley, Thaddeus C; Amos, Joshua D; Kumar, Amit; Hora, Bhavna; Marshall, Dawn J; Whitesides, John F; Xia, Shi-Mao; Parks, Robert; Lloyd, Krissey E; Hwang, Kwan-Ki; Lu, Xiaozhi; Bonsignori, Mattia; Finzi, Andrés; Vandergrift, Nathan A; Alam, S Munir; Ferrari, Guido; Shen, Xiaoying; Tomaras, Georgia D; Kamanga, Gift; Cohen, Myron S; Sam, Noel E; Kapiga, Saidi; Gray, Elin S; Tumba, Nancy L; Morris, Lynn; Zolla-Pazner, Susan; Gorny, Miroslaw K; Mascola, John R; Hahn, Beatrice H; Shaw, George M; Sodroski, Joseph G; Liao, Hua-Xin; Montefiori, David C; Hraber, Peter T; Korber, Bette T; Haynes, Barton F

2015-09-09

The third variable (V3) loop and the CD4 binding site (CD4bs) of the HIV-1 envelope are frequently targeted by neutralizing antibodies (nAbs) in infected individuals. In chronic infection, HIV-1 escape mutants repopulate the plasma, and V3 and CD4bs nAbs emerge that can neutralize heterologous tier 1 easy-to-neutralize but not tier 2 difficult-to-neutralize HIV-1 isolates. However, neutralization sensitivity of autologous plasma viruses to this type of nAb response has not been studied. We describe the development and evolution in vivo of antibodies distinguished by their target specificity for V3 and CD4bs epitopes on autologous tier 2 viruses but not on heterologous tier 2 viruses. A surprisingly high fraction of autologous circulating viruses was sensitive to these antibodies. These findings demonstrate a role for V3 and CD4bs antibodies in constraining the native envelope trimer in vivo to a neutralization-resistant phenotype, explaining why HIV-1 transmission generally occurs by tier 2 neutralization-resistant viruses. Copyright © 2015 Elsevier Inc. All rights reserved.

Action Centered Contextual Bandits.

PubMed

Greenewald, Kristjan; Tewari, Ambuj; Klasnja, Predrag; Murphy, Susan

2017-12-01

Contextual bandits have become popular as they offer a middle ground between very simple approaches based on multi-armed bandits and very complex approaches using the full power of reinforcement learning. They have demonstrated success in web applications and have a rich body of associated theoretical guarantees. Linear models are well understood theoretically and preferred by practitioners because they are not only easily interpretable but also simple to implement and debug. Furthermore, if the linear model is true, we get very strong performance guarantees. Unfortunately, in emerging applications in mobile health, the time-invariant linear model assumption is untenable. We provide an extension of the linear model for contextual bandits that has two parts: baseline reward and treatment effect. We allow the former to be complex but keep the latter simple. We argue that this model is plausible for mobile health applications. At the same time, it leads to algorithms with strong performance guarantees as in the linear model setting, while still allowing for complex nonlinear baseline modeling. Our theory is supported by experiments on data gathered in a recently concluded mobile health study.

Confronting the realities of implementing contextual learning ideas in a biology classroom

NASA Astrophysics Data System (ADS)

Akers, Julia B.

1999-10-01

The purpose of this study was to describe the implementation of contextual learning practices in a biology class. Research contends that contextual learning classrooms are active learning environments where students are involved in "hands-on" team projects and the teacher assumes a facilitator role. In this student-centered classroom, students take ownership and responsibility for their own learning. This study examined these assertions and other factors that emerged as the study developed. The research methods used were qualitative. The subject for this study was a biology teacher with twenty-six years of experience who implemented contextual learning practices in two of her biology classes in the 1997--98 school year. As the teacher confronted contextual learning, we engaged in collaborative research that included fourteen interviews transcribed verbatim for analysis, classroom observations and the teacher's written reports. Throughout the study, factors developed that adversely affected contextual learning practices. These factors were discipline, curriculum, and administrative decisions over which the teacher had no control. These are examined along with their consequences for implementing a contextual classroom. Successful practices that worked in the teacher's classroom were also determined and included the teacher's "failure is not an option" policy, mandatory tutoring, behavior contracts, high expectations and teamed projects. Besides contextual learning, a key component of the study was the collaborative research process and its meaning to the subject, the researcher and future researchers who attempt this collaborative approach. The study's conclusion indicate that scheduling, multiple repeaters, discipline and the state Standards of Learning moved the teacher away from contextual learning practices to a more teacher-directed classroom. Two recommendations of this study are that further research is needed to study how the state Standards of Learning have

The interplay of contextual elements in implementation: an ethnographic case study.

PubMed

McCullough, Megan B; Chou, Ann F; Solomon, Jeffrey L; Petrakis, Beth Ann; Kim, Bo; Park, Angela M; Benedict, Ashley J; Hamilton, Alison B; Rose, Adam J

2015-02-14

Contextual elements have significant impact on uptake of health care innovations. While existing conceptual frameworks in implementation science suggest contextual elements interact with each other, little research has described how this might look in practice. To bridge this gap, this study identifies the interconnected patterns among contextual elements that influence uptake of an anticoagulation clinic improvement initiative. We completed 51 semi-structured interviews and ethnographic observations across five case study sites involved in an evidence-based practice (EBP) quality improvement initiative. We analyzed data in NVivo 10 using an a priori approach based on the Promoting Action on Research Implementation in Health Services (PARIHS) model and an emergent thematic analysis. Key contextual elements, such as leadership, teamwork, and communication, interacted with each other in contributing to site-level uptake of the EBP, often yielding results that could not be predicted by looking at just one of these elements alone. Sites with context conducive to change in these areas predictably had high uptake, while sites with uniformly weak contextual elements had low uptake. Most sites presented a mixed picture, with contextual elements being strongly supportive of change in some areas and weak or moderate in others. In some cases, we found that sites with strong context in at least one area only needed to have adequate context in other areas to yield high uptake. At other sites, weak context in just one area had the potential to contribute to low uptake, despite countervailing strengths. Even a site with positive views of EBPs could not succeed when context was weak. Interrelationships among different contextual elements can act as barriers to uptake at some sites and as facilitators at others. Accounting for interconnections among elements enables PARIHS to more fully describe the determinants of successful implementation as they operate in real-world settings.

Personal and Contextual Factors Affecting the Functional Ability of Children and Adolescents with Chronic Pain: A Systematic Review.

PubMed

Sinclair, Cate M; Meredith, Pamela; Strong, Jenny; Feeney, Rachel

2016-05-01

Chronic pain can significantly impair functioning of children and adolescents; however, evidence suggests that current psychological approaches have limited effect on functioning post treatment. The objective of this review is to present the current evidence for the personal and contextual factors that affect functioning and disability of children and adolescents with chronic pain, to support the evolution of new treatments. Key word searches were conducted in PsycINFO, MEDLINE via Ovid, CINAHL, and PubMed from 1995 to October 2014. Studies were included if they (1) were written in English, (2) included children or adolescents with chronic pain (>3 mo), (3) had at least 1 personal attribute or 1 contextual factor, (4) had 1 measure of functional ability, and (5) had reported correlations between personal or contextual factors and functional measure. Thirty-three studies were identified which met all inclusion criteria. Several personal factors (depression, anxiety, pain intensity, and catastrophizing) and contextual/environmental factors (parenting characteristics) were consistently associated with higher levels of disability, whereas evidence for other factors was less consistent. Complex interactions between personal and contextual factors were reported. Child physical/cognitive capacities, teacher/peer behaviors, and broader cultural and environmental social systems, received little attention. Several parent and child factors were consistently linked with functional disability, whereas better family functioning was associated with functional ability. Applying an ecological framework, assisted identification of areas for further research, and provides direction for treatments that may be more effective in optimizing long-term functional outcomes, extending current psychological approaches.

Implicit contextual learning in prodromal and early stage Huntington's disease patients.

PubMed

van Asselen, Marieke; Almeida, Inês; Júlio, Filipa; Januário, Cristina; Campos, Elzbieta Bobrowicz; Simões, Mário; Castelo-Branco, Miguel

2012-07-01

Huntington's disease (HD) is a genetic neurodegenerative disorder affecting the basal ganglia. These subcortical structures are particularly important for motor functions, response selection and implicit learning. In the current study, we have assessed prodromal and symptomatic HD participants with an implicit contextual learning task that is not based on motor learning, but on a purely visual implicit learning mechanism. We used an implicit contextual learning task in which subjects need to locate a target among several distractors. In half of the trials, the positions of the distractors and target stimuli were repeated. By memorizing this contextual information, attention can be guided faster to the target stimulus. Nine symptomatic HD participants, 16 prodromal HD participants and 22 control subjects were included. We found that the responses of the control subjects were faster for the repeated trials than for the new trials, indicating that their visual search was facilitated when repeated contextual information was present. In contrast, no difference in response times between the repeated and new trials was found for the symptomatic and prodromal HD participants. The results of the current study indicate that both prodromal and symptomatic HD participants are impaired on an implicit contextual learning task.

What a Smile Means: Contextual Beliefs and Facial Emotion Expressions in a Non-verbal Zero-Sum Game

PubMed Central

Pádua Júnior, Fábio P.; Prado, Paulo H. M.; Roeder, Scott S.; Andrade, Eduardo B.

2016-01-01

Research into the authenticity of facial emotion expressions often focuses on the physical properties of the face while paying little attention to the role of beliefs in emotion perception. Further, the literature most often investigates how people express a pre-determined emotion rather than what facial emotion expressions people strategically choose to express. To fill these gaps, this paper proposes a non-verbal zero-sum game – the Face X Game – to assess the role of contextual beliefs and strategic displays of facial emotion expression in interpersonal interactions. This new research paradigm was used in a series of three studies, where two participants are asked to play the role of the sender (individual expressing emotional information on his/her face) or the observer (individual interpreting the meaning of that expression). Study 1 examines the outcome of the game with reference to the sex of the pair, where senders won more frequently when the pair was comprised of at least one female. Study 2 examines the strategic display of facial emotion expressions. The outcome of the game was again contingent upon the sex of the pair. Among female pairs, senders won the game more frequently, replicating the pattern of results from study 1. We also demonstrate that senders who strategically express an emotion incongruent with the valence of the event (e.g., smile after seeing a negative event) are able to mislead observers, who tend to hold a congruent belief about the meaning of the emotion expression. If sending an incongruent signal helps to explain why female senders win more frequently, it logically follows that female observers were more prone to hold a congruent, and therefore inaccurate, belief. This prospect implies that while female senders are willing and/or capable of displaying fake smiles, paired-female observers are not taking this into account. Study 3 investigates the role of contextual factors by manipulating female observers’ beliefs. When

UBVR observation of V1357 Cyg = Cyg X-1. Search of the optical radiation of the accretion disk

NASA Technical Reports Server (NTRS)

Shevchenko, V. S.

1979-01-01

Data from 30 nights of V 1357 Cyg observations in July, August, and September of 1977 are presented. The contribution of the disk to the optic brightness of the system is computed with regard for the heating of its surface by ultraviolet radiation from V 1357 Cyg and X-ray radiation from Cyg X-1. The disk radiation explains the irregular variability in the system brightness. The possibility of the eclipse of the star by the disk and the disk by the star is discussed.

Neural Correlates of Contextual Cueing Are Modulated by Explicit Learning

ERIC Educational Resources Information Center

Westerberg, Carmen E.; Miller, Brennan B.; Reber, Paul J.; Cohen, Neal J.; Paller, Ken A.

2011-01-01

Contextual cueing refers to the facilitated ability to locate a particular visual element in a scene due to prior exposure to the same scene. This facilitation is thought to reflect implicit learning, as it typically occurs without the observer's knowledge that scenes repeat. Unlike most other implicit learning effects, contextual cueing can be…

MetaBar - a tool for consistent contextual data acquisition and standards compliant submission.

PubMed

Hankeln, Wolfgang; Buttigieg, Pier Luigi; Fink, Dennis; Kottmann, Renzo; Yilmaz, Pelin; Glöckner, Frank Oliver

2010-06-30

Environmental sequence datasets are increasing at an exponential rate; however, the vast majority of them lack appropriate descriptors like sampling location, time and depth/altitude: generally referred to as metadata or contextual data. The consistent capture and structured submission of these data is crucial for integrated data analysis and ecosystems modeling. The application MetaBar has been developed, to support consistent contextual data acquisition. MetaBar is a spreadsheet and web-based software tool designed to assist users in the consistent acquisition, electronic storage, and submission of contextual data associated to their samples. A preconfigured Microsoft Excel spreadsheet is used to initiate structured contextual data storage in the field or laboratory. Each sample is given a unique identifier and at any stage the sheets can be uploaded to the MetaBar database server. To label samples, identifiers can be printed as barcodes. An intuitive web interface provides quick access to the contextual data in the MetaBar database as well as user and project management capabilities. Export functions facilitate contextual and sequence data submission to the International Nucleotide Sequence Database Collaboration (INSDC), comprising of the DNA DataBase of Japan (DDBJ), the European Molecular Biology Laboratory database (EMBL) and GenBank. MetaBar requests and stores contextual data in compliance to the Genomic Standards Consortium specifications. The MetaBar open source code base for local installation is available under the GNU General Public License version 3 (GNU GPL3). The MetaBar software supports the typical workflow from data acquisition and field-sampling to contextual data enriched sequence submission to an INSDC database. The integration with the megx.net marine Ecological Genomics database and portal facilitates georeferenced data integration and metadata-based comparisons of sampling sites as well as interactive data visualization. The ample export

Effects of contextual relevance on pragmatic inference during conversation: An fMRI study.

PubMed

Feng, Wangshu; Wu, Yue; Jan, Catherine; Yu, Hongbo; Jiang, Xiaoming; Zhou, Xiaolin

2017-08-01

Contextual relevance, which is vital for understanding conversational implicatures (CI), engages both the frontal-temporal language and theory-of-mind networks. Here we investigate how contextual relevance affects CI processing and regulates the connectivity between CI-processing-related brain regions. Participants listened to dialogues in which the level of contextual relevance to dialogue-final utterance (reply) was manipulated. This utterance was either direct, indirect but relevant, irrelevant with contextual hint, or irrelevant with no contextual hint. Results indicated that compared with direct replies, indirect replies showed increased activations in bilateral IFG, bilateral MTG, bilateral TPJ, dmPFC, and precuneus, and increased connectivity between rTPJ/dmPFC and both IFG and MTG. Moreover, irrelevant replies activated right MTG along an anterior-posterior gradient as a function of the level of irrelevance. Our study provides novel evidence concerning how the language and theory-of-mind networks interact for pragmatic inference and how the processing of CI is modulated by level of contextual relevance. Copyright © 2017 Elsevier Inc. All rights reserved.

From Foreground to Background: How Task-Neutral Context Influences Contextual Cueing of Visual Search.

PubMed

Zang, Xuelian; Geyer, Thomas; Assumpção, Leonardo; Müller, Hermann J; Shi, Zhuanghua

2016-01-01

Selective attention determines the effectiveness of implicit contextual learning (e.g., Jiang and Leung, 2005). Visual foreground-background segmentation, on the other hand, is a key process in the guidance of attention (Wolfe, 2003). In the present study, we examined the impact of foreground-background segmentation on contextual cueing of visual search in three experiments. A visual search display, consisting of distractor 'L's and a target 'T', was overlaid on a task-neutral cuboid on the same depth plane (Experiment 1), on stereoscopically separated depth planes (Experiment 2), or spread over the entire display on the same depth plane (Experiment 3). Half of the search displays contained repeated target-distractor arrangements, whereas the other half was always newly generated. The task-neutral cuboid was constant during an initial training session, but was either rotated by 90° or entirely removed in the subsequent test sessions. We found that the gains resulting from repeated presentation of display arrangements during training (i.e., contextual-cueing effects) were diminished when the cuboid was changed or removed in Experiment 1, but remained intact in Experiments 2 and 3 when the cuboid was placed in a different depth plane, or when the items were randomly spread over the whole display but not on the edges of the cuboid. These findings suggest that foreground-background segmentation occurs prior to contextual learning, and only objects/arrangements that are grouped as foreground are learned over the course of repeated visual search.

Sodium channel diversity in the vestibular ganglion: NaV1.5, NaV1.8, and tetrodotoxin-sensitive currents

PubMed Central

2016-01-01

Firing patterns differ between subpopulations of vestibular primary afferent neurons. The role of sodium (NaV) channels in this diversity has not been investigated because NaV currents in rodent vestibular ganglion neurons (VGNs) were reported to be homogeneous, with the voltage dependence and tetrodotoxin (TTX) sensitivity of most neuronal NaV channels. RT-PCR experiments, however, indicated expression of diverse NaV channel subunits in the vestibular ganglion, motivating a closer look. Whole cell recordings from acutely dissociated postnatal VGNs confirmed that nearly all neurons expressed NaV currents that are TTX-sensitive and have activation midpoints between −30 and −40 mV. In addition, however, many VGNs expressed one of two other NaV currents. Some VGNs had a small current with properties consistent with NaV1.5 channels: low TTX sensitivity, sensitivity to divalent cation block, and a relatively negative voltage range, and some VGNs showed NaV1.5-like immunoreactivity. Other VGNs had a current with the properties of NaV1.8 channels: high TTX resistance, slow time course, and a relatively depolarized voltage range. In two NaV1.8 reporter lines, subsets of VGNs were labeled. VGNs with NaV1.8-like TTX-resistant current also differed from other VGNs in the voltage dependence of their TTX-sensitive currents and in the voltage threshold for spiking and action potential shape. Regulated expression of NaV channels in primary afferent neurons is likely to selectively affect firing properties that contribute to the encoding of vestibular stimuli. PMID:26936982

A Model of How Different Biology Experts Explain Molecular and Cellular Mechanisms

PubMed Central

Trujillo, Caleb M.; Anderson, Trevor R.; Pelaez, Nancy J.

2015-01-01

Constructing explanations is an essential skill for all science learners. The goal of this project was to model the key components of expert explanation of molecular and cellular mechanisms. As such, we asked: What is an appropriate model of the components of explanation used by biology experts to explain molecular and cellular mechanisms? Do explanations made by experts from different biology subdisciplines at a university support the validity of this model? Guided by the modeling framework of R. S. Justi and J. K. Gilbert, the validity of an initial model was tested by asking seven biologists to explain a molecular mechanism of their choice. Data were collected from interviews, artifacts, and drawings, and then subjected to thematic analysis. We found that biologists explained the specific activities and organization of entities of the mechanism. In addition, they contextualized explanations according to their biological and social significance; integrated explanations with methods, instruments, and measurements; and used analogies and narrated stories. The derived methods, analogies, context, and how themes informed the development of our final MACH model of mechanistic explanations. Future research will test the potential of the MACH model as a guiding framework for instruction to enhance the quality of student explanations. PMID:25999313

V-1 regulates capping protein activity in vivo.

PubMed

Jung, Goeh; Alexander, Christopher J; Wu, Xufeng S; Piszczek, Grzegorz; Chen, Bi-Chang; Betzig, Eric; Hammer, John A

2016-10-25

Capping Protein (CP) plays a central role in the creation of the Arp2/3-generated branched actin networks comprising lamellipodia and pseudopodia by virtue of its ability to cap the actin filament barbed end, which promotes Arp2/3-dependent filament nucleation and optimal branching. The highly conserved protein V-1/Myotrophin binds CP tightly in vitro to render it incapable of binding the barbed end. Here we addressed the physiological significance of this CP antagonist in Dictyostelium, which expresses a V-1 homolog that we show is very similar biochemically to mouse V-1. Consistent with previous studies of CP knockdown, overexpression of V-1 in Dictyostelium reduced the size of pseudopodia and the cortical content of Arp2/3 and induced the formation of filopodia. Importantly, these effects scaled positively with the degree of V-1 overexpression and were not seen with a V-1 mutant that cannot bind CP. V-1 is present in molar excess over CP, suggesting that it suppresses CP activity in the cytoplasm at steady state. Consistently, cells devoid of V-1, like cells overexpressing CP described previously, exhibited a significant decrease in cellular F-actin content. Moreover, V-1-null cells exhibited pronounced defects in macropinocytosis and chemotactic aggregation that were rescued by V-1, but not by the V-1 mutant. Together, these observations demonstrate that V-1 exerts significant influence in vivo on major actin-based processes via its ability to sequester CP. Finally, we present evidence that V-1's ability to sequester CP is regulated by phosphorylation, suggesting that cells may manipulate the level of active CP to tune their "actin phenotype."

V1 projection zone signals in human macular degeneration depend on task, not stimulus.

PubMed

Masuda, Yoichiro; Dumoulin, Serge O; Nakadomari, Satoshi; Wandell, Brian A

2008-11-01

We used functional magnetic resonance imaging to assess abnormal cortical signals in humans with juvenile macular degeneration (JMD). These signals have been interpreted as indicating large-scale cortical reorganization. Subjects viewed a stimulus passively or performed a task; the task was either related or unrelated to the stimulus. During passive viewing, or while performing tasks unrelated to the stimulus, there were large unresponsive V1 regions. These regions included the foveal projection zone, and we refer to them as the lesion projection zone (LPZ). In 3 JMD subjects, we observed highly significant responses in the LPZ while they performed stimulus-related judgments. In control subjects, where we presented the stimulus only within the peripheral visual field, there was no V1 response in the foveal projection zone in any condition. The difference between JMD and control responses can be explained by hypotheses that have very different implications for V1 reorganization. In controls retinal afferents carry signals indicating the presence of a uniform (zero-contrast) region of the visual field. Deletion of retinal input may 1) spur the formation of new cortical pathways that carry task-dependent signals (reorganization), or 2) unmask preexisting task-dependent cortical signals that ordinarily are suppressed by the deleted signals (no reorganization).

V1 Projection Zone Signals in Human Macular Degeneration Depend on Task, not Stimulus

PubMed Central

Dumoulin, Serge O.; Nakadomari, Satoshi; Wandell, Brian A.

2008-01-01

We used functional magnetic resonance imaging to assess abnormal cortical signals in humans with juvenile macular degeneration (JMD). These signals have been interpreted as indicating large-scale cortical reorganization. Subjects viewed a stimulus passively or performed a task; the task was either related or unrelated to the stimulus. During passive viewing, or while performing tasks unrelated to the stimulus, there were large unresponsive V1 regions. These regions included the foveal projection zone, and we refer to them as the lesion projection zone (LPZ). In 3 JMD subjects, we observed highly significant responses in the LPZ while they performed stimulus-related judgments. In control subjects, where we presented the stimulus only within the peripheral visual field, there was no V1 response in the foveal projection zone in any condition. The difference between JMD and control responses can be explained by hypotheses that have very different implications for V1 reorganization. In controls retinal afferents carry signals indicating the presence of a uniform (zero-contrast) region of the visual field. Deletion of retinal input may 1) spur the formation of new cortical pathways that carry task-dependent signals (reorganization), or 2) unmask preexisting task-dependent cortical signals that ordinarily are suppressed by the deleted signals (no reorganization). PMID:18250083

Parallel processing implementations of a contextual classifier for multispectral remote sensing data

NASA Technical Reports Server (NTRS)

Siegel, H. J.; Swain, P. H.; Smith, B. W.

1980-01-01

Contextual classifiers are being developed as a method to exploit the spatial/spectral context of a pixel to achieve accurate classification. Classification algorithms such as the contextual classifier typically require large amounts of computation time. One way to reduce the execution time of these tasks is through the use of parallelism. The applicability of the CDC flexible processor system and of a proposed multimicroprocessor system (PASM) for implementing contextual classifiers is examined.

75 FR 6860 - Airworthiness Directives; International Aero Engines AG (IAE) V2500-A1, V2522-A5, V2524-A5, V2525...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-12

... Airworthiness Directives; International Aero Engines AG (IAE) V2500-A1, V2522-A5, V2524-A5, V2525-D5, V2527-A5, V2527E-A5, V2527M-A5, V2528-D5, V2530-A5, and V2533-A5 Turbofan Engines AGENCY: Federal Aviation... airworthiness directive (AD) for all International Aero Engines AG (IAE) V2500-A1, V2525-D5 and V2528-D5...

Recurrent connectivity can account for the dynamics of disparity processing in V1

PubMed Central

Samonds, Jason M.; Potetz, Brian R.; Tyler, Christopher W.; Lee, Tai Sing

2013-01-01

Disparity tuning measured in the primary visual cortex (V1) is described well by the disparity energy model, but not all aspects of disparity tuning are fully explained by the model. Such deviations from the disparity energy model provide us with insight into how network interactions may play a role in disparity processing and help to solve the stereo correspondence problem. Here, we propose a neuronal circuit model with recurrent connections that provides a simple account of the observed deviations. The model is based on recurrent connections inferred from neurophysiological observations on spike timing correlations, and is in good accord with existing data on disparity tuning dynamics. We further performed two additional experiments to test predictions of the model. First, we increased the size of stimuli to drive more neurons and provide a stronger recurrent input. Our model predicted sharper disparity tuning for larger stimuli. Second, we displayed anti-correlated stereograms, where dots of opposite luminance polarity are matched between the left- and right-eye images and result in inverted disparity tuning in the disparity energy model. In this case, our model predicted reduced sharpening and strength of inverted disparity tuning. For both experiments, the dynamics of disparity tuning observed from the neurophysiological recordings in macaque V1 matched model simulation predictions. Overall, the results of this study support the notion that, while the disparity energy model provides a primary account of disparity tuning in V1 neurons, neural disparity processing in V1 neurons is refined by recurrent interactions among elements in the neural circuit. PMID:23407952

Ecological theories of systems and contextual change in medical education.