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Sample records for local elements distractor

  1. Localizing semantic interference from distractor sounds in picture naming: A dual-task study.

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    Mädebach, Andreas; Kieseler, Marie-Luise; Jescheniak, Jörg D

    2017-10-13

    In this study we explored the locus of semantic interference in a novel picture-sound interference task in which participants name pictures while ignoring environmental distractor sounds. In a previous study using this task (Mädebach, Wöhner, Kieseler, & Jescheniak, in Journal of Experimental Psychology: Human Perception and Performance, 43, 1629-1646, 2017), we showed that semantically related distractor sounds (e.g., BARKING dog ) interfere with a picture-naming response (e.g., "horse") more strongly than unrelated distractor sounds do (e.g., DRUMMING drum ). In the experiment reported here, we employed the psychological refractory period (PRP) approach to explore the locus of this effect. We combined a geometric form classification task (square vs. circle; Task 1) with the picture-sound interference task (Task 2). The stimulus onset asynchrony (SOA) between the tasks was systematically varied (0 vs. 500 ms). There were three central findings. First, the semantic interference effect from distractor sounds was replicated. Second, picture naming (in Task 2) was slower with the short than with the long task SOA. Third, both effects were additive-that is, the semantic interference effects were of similar magnitude at both task SOAs. This suggests that the interference arises during response selection or later stages, not during early perceptual processing. This finding corroborates the theory that semantic interference from distractor sounds reflects a competitive selection mechanism in word production.

  2. Distractor inhibition: Evidence from lateralized readiness potentials.

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    Pramme, Lisa; Dierolf, Angelika M; Naumann, Ewald; Frings, Christian

    2015-08-01

    The present study investigated distractor inhibition on the level of stimulus representation. In a sequential distractor-to-distractor priming task participants had to respond to target letters flanked by distractor digits. Reaction time and stimulus-locked lateralized readiness potentials (S-LRPs) of probe responses were measured. Distractor-target onset asynchrony was varied. For RTs responses to probe targets were faster in the case of prime-distractor repetition compared to distractor changes indicating distractor inhibition. Benefits in RTs and the latency of S-LRP onsets for distractor repetition were also modulated by distractor-target onset asynchrony. For S-LRPs distractor inhibition was only present with a simultaneous onset of distractors and target. The results confirm previous results indicating inhibitory mechanisms of object-based selective attention on the level of distractor representations. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Low cognitive load strengthens distractor interference while high load attenuates when cognitive load and distractor possess similar visual characteristics.

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    Minamoto, Takehiro; Shipstead, Zach; Osaka, Naoyuki; Engle, Randall W

    2015-07-01

    Studies on visual cognitive load have reported inconsistent effects of distractor interference when distractors have visual characteristic that are similar to the cognitive load. Some studies have shown that the cognitive load enhances distractor interference, while others reported an attenuating effect. We attribute these inconsistencies to the amount of cognitive load that a person is required to maintain. Lower amounts of cognitive load increase distractor interference by orienting attention toward visually similar distractors. Higher amounts of cognitive load attenuate distractor interference by depleting attentional resources needed to process distractors. In the present study, cognitive load consisted of faces (Experiments 1-3) or scenes (Experiment 2). Participants performed a selective attention task in which they ignored face distractors while judging a color of a target dot presented nearby, under differing amounts of load. Across these experiments distractor interference was greater in the low-load condition and smaller in the high-load condition when the content of the cognitive load had similar visual characteristic to the distractors. We also found that when a series of judgments needed to be made, the effect was apparent for the first trial but not for the second. We further tested an involvement of working memory capacity (WMC) in the load effect (Experiment 3). Interestingly, both high and low WMC groups received an equivalent effect of the cognitive load in the first distractor, suggesting these effects are fairly automatic.

  4. Saccadic distractor effects: the remote distractor effect (RDE) and saccadic inhibition (SI): A response to McIntosh and Buonocore (2014).

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    Walker, Robin; Benson, Valerie

    2015-02-04

    We (Walker & Benson, 2013) reported studies in which the spatial effects of distractors on the remote distractor effect (RDE) and saccadic inhibition (SI) were examined. Distractors remote from the target increased mean latency and the skew of the distractor-related distributions, without the presence of dips that are regarded as the hallmark of SI. We further showed that early onset distractors had similar effects although these would not be consistent with existing estimates of the duration of SI (of around 60-70 ms). McIntosh and Buonocore (2014) report a simulation showing that skewed latency distributions can arise from the putative SI mechanism and they also highlighted a number of methodological considerations regarding the RDE and SI as measures of saccadic distractor effects (SDEs). Here we evaluate these claims and note that the measures of SI obtained by subtracting latency distributions (specifically the decrease in saccade frequency--or dip duration) are no more diagnostic of a single inhibitory process, or more sensitive indicators of it, than is median latency. Furthermore the evidence of inhibitory influences of small distractors presented close to the target is incompatible with the explanations of both the RDE and SI. We conclude that saccadic distractor effects may be a more inclusive term to encompass the different characteristics of behavioral effects of underlying saccade target selection. © 2015 ARVO.

  5. Predictive distractor context facilitates attentional selection of high, but not intermediate and low, salience targets.

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    Töllner, Thomas; Conci, Markus; Müller, Hermann J

    2015-03-01

    It is well established that we can focally attend to a specific region in visual space without shifting our eyes, so as to extract action-relevant sensory information from covertly attended locations. The underlying mechanisms that determine how fast we engage our attentional spotlight in visual-search scenarios, however, remain controversial. One dominant view advocated by perceptual decision-making models holds that the times taken for focal-attentional selection are mediated by an internal template that biases perceptual coding and selection decisions exclusively through target-defining feature coding. This notion directly predicts that search times remain unaffected whether or not participants can anticipate the upcoming distractor context. Here we tested this hypothesis by employing an illusory-figure localization task that required participants to search for an invariant target amongst a variable distractor context, which gradually changed--either randomly or predictably--as a function of distractor-target similarity. We observed a graded decrease in internal focal-attentional selection times--correlated with external behavioral latencies--for distractor contexts of higher relative to lower similarity to the target. Critically, for low but not intermediate and high distractor-target similarity, these context-driven effects were cortically and behaviorally amplified when participants could reliably predict the type of distractors. This interactive pattern demonstrates that search guidance signals can integrate information about distractor, in addition to target, identities to optimize distractor-target competition for focal-attentional selection. © 2014 Wiley Periodicals, Inc.

  6. Remote distractor effects and saccadic inhibition: spatial and temporal modulation.

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    Walker, Robin; Benson, Valerie

    2013-09-12

    The onset of a visual distractor remote from a saccade target is known to increase saccade latency (the remote distractor effect [RDE]). In addition, distractors may also selectively inhibit saccades that would be initiated about 90 ms after distractor onset (termed saccadic inhibition [SI]). Recently, it has been proposed that the transitory inhibition of saccades (SI) may underlie the increase in mean latency (RDE). In a first experiment, the distractor eccentricity was manipulated, and a robust RDE that was strongly modulated by distractor eccentricity was observed. However, the underlying latency distributions did not reveal clear evidence of SI. A second experiment manipulated distractor spatial location and the timing of the distractor onset in relation to the target. An RDE was again observed with remote distractors away from the target axis and under conditions with early-onset distractors that would be unlikely to produce SI, whereas later distractor onsets produced an RDE along with some evidence of an SI effect. A third experiment using a mixed block of target-distractor stimulus-onset asynchronies (SOAs) revealed an RDE that varied with both distractor eccentricity and SOA and changes to latency distributions consistent with the timing of SI. We argue that the notion that SI underpins the RDE is similar to the earlier argument that express saccades underlie the fixation offset (gap) effect and that changes in mean latency and to the shape of the underlying latency distributions following a visual onset may involve more than one inhibitory process.

  7. Adaptability and specificity of inhibition processes in distractor-induced blindness.

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    Winther, Gesche N; Niedeggen, Michael

    2017-12-01

    In a rapid serial visual presentation task, inhibition processes cumulatively impair processing of a target possessing distractor properties. This phenomenon-known as distractor-induced blindness-has thus far only been elicited using dynamic visual features, such as motion and orientation changes. In three ERP experiments, we used a visual object feature-color-to test for the adaptability and specificity of the effect. In Experiment I, participants responded to a color change (target) in the periphery whose onset was signaled by a central cue. Presentation of irrelevant color changes prior to the cue (distractors) led to reduced target detection, accompanied by a frontal ERP negativity that increased with increasing number of distractors, similar to the effects previously found for dynamic targets. This suggests that distractor-induced blindness is adaptable to color features. In Experiment II, the target consisted of coherent motion contrasting the color distractors. Correlates of distractor-induced blindness were found neither in the behavioral nor in the ERP data, indicating a feature specificity of the process. Experiment III confirmed the strict distinction between congruent and incongruent distractors: A single color distractor was embedded in a stream of motion distractors with the target consisting of a coherent motion. While behavioral performance was affected by the distractors, the color distractor did not elicit a frontal negativity. The experiments show that distractor-induced blindness is also triggered by visual stimuli predominantly processed in the ventral stream. The strict specificity of the central inhibition process also applies to these stimulus features. © 2017 Society for Psychophysiological Research.

  8. Using environmental distractors in the diagnosis of ADHD

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    Hanoch eCassuto

    2013-11-01

    Full Text Available This study examined the effect of the incorporation of environmental distractors in computerized continuous performance test (CPT on the ability of the test in distinguishing ADHD from non-ADHD children. It was hypothesized that children with ADHD would display more distractibility than controls while performing CPT as measured by omission errors in the presence of pure visual, pure auditory, and a combination of visual and auditory distracting stimuli. Participants were 663 children aged 7-12 years, of them 345 diagnosed with ADHD and 318 without ADHD. Results showed that ADHD children demonstrated more omission errors than their healthy peers in all CPT conditions (no distractors, pure visual or auditory distractors and combined distractors. However, ADHD and non- ADHD children differed in their reaction to distracting stimuli; while all types of distracting stimuli increased the rate of omission errors in ADHD children, only combined visual and auditory distractors increased it in non-ADHD children. Given the low ecological validity of many CPT, these findings suggest that incorporating distractors in CPT improves the ability to distinguish ADHD from non-ADHD children.

  9. Distractor interference during a choice limb reaching task.

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    Matthew Ray

    Full Text Available According to action-centered models of attention, the patterns of distractor interference that emerge in selective reaching tasks are related to the time and effort required to resolve a race for activation between competing target and non-target response producing processes. Previous studies have only used unimanual aiming tasks and, as such, only examined the effects of competition that occurs within a limb. The results of studies using unimanual aiming movements often reveal an "ipsilateral effect"--distractors on the same side of space as the effector cause greater interference than distractors on the opposite side of space. The cost of the competition when response selection is between the limbs has yet to be addressed. Participants in the present study executed reaching movements to 1 of 4 (2 left, 2 right possible target locations with and without a distractor. Participants made ipsilateral reaches (left hand to left targets, right hand to right targets. In contrast to studies using unimanual aiming movements, a "contralateral effect" was observed; distractors affording responses for the other hand (in contralateral space caused more interference than distractors affording responses for the same hand. The findings from the present research demonstrate that when certain portions of response planning must be resolved prior to response initiation, distractors that code for that dimension cause the greatest interference.

  10. Low level perceptual, not attentional, processes modulate distractor interference in high perceptual load displays: evidence from neglect/extinction.

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    Mevorach, Carmel; Tsal, Yehoshua; Humphreys, Glyn W

    2014-01-10

    According to perceptual load theory (Lavie, 2005) distractor interference is determined by the availability of attentional resources. If target processing does not exhaust resources (with low perceptual load) distractor processing will take place resulting in interference with a primary task; however, when target processing uses-up attentional capacity (with high perceptual load) interference can be avoided. An alternative account (Tsal and Benoni, 2010a) suggests that perceptual load effects can be based on distractor dilution by the mere presence of additional neutral items in high-load displays so that the effect is not driven by the amount of attention resources required for target processing. Here we tested whether patients with unilateral neglect or extinction would show dilution effects from neutral items in their contralesional (neglected/extinguished) field, even though these items do not impose increased perceptual load on the target and at the same time attract reduced attentional resources compared to stimuli in the ipsilesional field. Thus, such items do not affect the amount of attention resources available for distractor processing. We found that contralesional neutral elements can eliminate distractor interference as strongly as centrally presented ones in neglect/extinction patients, despite contralesional items being less well attended. The data are consistent with an account in terms of perceptual dilution of distracters rather than available resources for distractor processing. We conclude that distractor dilution can underlie the elimination of distractor interference in visual displays.

  11. Low level perceptual, not attentional, processes modulate distractor interference in high perceptual Load displays: evidence from neglect/extinction

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    Carmel eMevorach

    2014-01-01

    Full Text Available According to perceptual load theory (Lavie, 2005 distractor interference is determined by the availability of attentional resources. If target processing does not exhaust resources (with low perceptual load distractor processing will take place resulting in interference with a primary task; however when target processing uses-up attentional capacity (with high perceptual load interference can be avoided. An alternative account (Tsal & Benoni, 2010 suggests that perceptual load effects can be based on distractor dilution by the mere presence of additional neutral items in high load displays so that the effect is not driven by the amount of attention resources required for target processing. Here we tested whether patients with unilateral neglect or extinction would show dilution effects from neutral items in their contralesional (neglected/extinguished field, even though these items do not impose increased perceptual load on the target and at the same time attract reduced attentional resources compared to stimuli in the ipsilesional field. Thus, such items do not affect the amount of attention resources available for distractor processing. We found that contralesional neutral elements can eliminate distractor interference as strongly as centrally presented ones in neglect/extinction patients, despite contralesional items being less well attended. The data are consistent with an account in terms of perceptual dilution of distracters rather than available resources for distractor processing. We conclude that distractor dilution can underlie the elimination of distractor interference in visual displays.

  12. The antisaccade task: visual distractors elicit a location-independent planning 'cost'.

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    DeSimone, Jesse C; Everling, Stefan; Heath, Matthew

    2015-01-01

    The presentation of a remote - but not proximal - distractor concurrent with target onset increases prosaccade reaction times (RT) (i.e., the remote distractor effect: RDE). The competitive integration model asserts that the RDE represents the time required to resolve the conflict for a common saccade threshold between target- and distractor-related saccade generating commands in the superior colliculus. To our knowledge however, no previous research has examined whether remote and proximal distractors differentially influence antisaccade RTs. This represents a notable question because antisaccades require decoupling of the spatial relations between stimulus and response (SR) and therefore provide a basis for determining whether the sensory- and/or motor-related features of a distractor influence response planning. Participants completed pro- and antisaccades in a target-only condition and conditions wherein the target was concurrently presented with a proximal or remote distractor. As expected, prosaccade RTs elicited a reliable RDE. In contrast, antisaccade RTs were increased independent of the distractor's spatial location and the magnitude of the effect was comparable across each distractor location. Thus, distractor-related antisaccade RT costs are not accounted for by a competitive integration between conflicting saccade generating commands. Instead, we propose that a visual distractor increases uncertainty related to the evocation of the response-selection rule necessary for decoupling SR relations.

  13. Probability cueing of distractor locations: both intertrial facilitation and statistical learning mediate interference reduction.

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    Goschy, Harriet; Bakos, Sarolta; Müller, Hermann J; Zehetleitner, Michael

    2014-01-01

    Targets in a visual search task are detected faster if they appear in a probable target region as compared to a less probable target region, an effect which has been termed "probability cueing." The present study investigated whether probability cueing cannot only speed up target detection, but also minimize distraction by distractors in probable distractor regions as compared to distractors in less probable distractor regions. To this end, three visual search experiments with a salient, but task-irrelevant, distractor ("additional singleton") were conducted. Experiment 1 demonstrated that observers can utilize uneven spatial distractor distributions to selectively reduce interference by distractors in frequent distractor regions as compared to distractors in rare distractor regions. Experiments 2 and 3 showed that intertrial facilitation, i.e., distractor position repetitions, and statistical learning (independent of distractor position repetitions) both contribute to the probability cueing effect for distractor locations. Taken together, the present results demonstrate that probability cueing of distractor locations has the potential to serve as a strong attentional cue for the shielding of likely distractor locations.

  14. Prolonged disengagement from distractors near the hands

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    Daniel B Vatterott

    2013-08-01

    Full Text Available Because items near our hands are often more important than items far from our hands, the brain processes visual items near our hands differently than items far from our hands. Multiple experiments have attributed this processing difference to spatial attention, but the exact mechanism behind how spatial attention near our hands changes is still under investigation. The current experiments sought to differentiate between two of the proposed mechanisms: a prioritization of the space near the hands and a prolonged disengagement of spatial attention near the hands. To differentiate between these two accounts, we used the additional singleton paradigm in which observers searched for a shape singleton among homogenously shaped distractors. On half the trials, one of the distractors was a different color. Both the prioritization and disengagement accounts predict differently colored distractors near the hands will slow target responses more than differently colored distractors far from the hands, but the prioritization account also predicts faster responses to targets near the hands than far from the hands. The disengagement account does not make this prediction, because attention does not need to be disengaged when the target appears near the hand. We found support for the disengagement account: Salient distractors near the hands slowed responses more than those far from the hands, yet observers did not respond faster to targets near the hands.

  15. Dissociated effects of distractors on saccades and manual aiming.

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    McIntosh, Robert D; Buonocore, Antimo

    2012-08-01

    The remote distractor effect (RDE) is a robust phenomenon whereby target-directed saccades are delayed by the appearance of a distractor. This effect persists even when the target location is perfectly predictable. The RDE has been studied extensively in the oculomotor domain but it is unknown whether it generalises to other spatially oriented responses. In three experiments, we tested whether the RDE generalises to manual aiming. Experiment 1 required participants to move their hand or eyes to predictable targets presented alone or accompanied by a distractor in the opposite hemifield. The RDE was observed for the eyes but not for the hand. Experiment 2 replicated this dissociation in a more naturalistic task in which eye movements were not constrained during manual aiming. Experiment 3 confirmed the lack of manual RDE across a wider range of distractor delays (0, 50, 100, and 150 ms). Our data imply that the RDE is specific to the oculomotor system, at least for non-foveal distractors. We suggest that the oculomotor RDE reflects competitive interactions between target and distractor representations in the superior colliculus, which are not necessarily shared by manual aiming.

  16. Different Neuroplasticity for Task Targets and Distractors

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    Spingath, Elsie Y.; Kang, Hyun Sug; Plummer, Thane; Blake, David T.

    2011-01-01

    Adult learning-induced sensory cortex plasticity results in enhanced action potential rates in neurons that have the most relevant information for the task, or those that respond strongly to one sensory stimulus but weakly to its comparison stimulus. Current theories suggest this plasticity is caused when target stimulus evoked activity is enhanced by reward signals from neuromodulatory nuclei. Prior work has found evidence suggestive of nonselective enhancement of neural responses, and suppression of responses to task distractors, but the differences in these effects between detection and discrimination have not been directly tested. Using cortical implants, we defined physiological responses in macaque somatosensory cortex during serial, matched, detection and discrimination tasks. Nonselective increases in neural responsiveness were observed during detection learning. Suppression of responses to task distractors was observed during discrimination learning, and this suppression was specific to cortical locations that sampled responses to the task distractor before learning. Changes in receptive field size were measured as the area of skin that had a significant response to a constant magnitude stimulus, and these areal changes paralleled changes in responsiveness. From before detection learning until after discrimination learning, the enduring changes were selective suppression of cortical locations responsive to task distractors, and nonselective enhancement of responsiveness at cortical locations selective for target and control skin sites. A comparison of observations in prior studies with the observed plasticity effects suggests that the non-selective response enhancement and selective suppression suffice to explain known plasticity phenomena in simple spatial tasks. This work suggests that differential responsiveness to task targets and distractors in primary sensory cortex for a simple spatial detection and discrimination task arise from nonselective

  17. Different neuroplasticity for task targets and distractors.

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    Elsie Y Spingath

    2011-01-01

    Full Text Available Adult learning-induced sensory cortex plasticity results in enhanced action potential rates in neurons that have the most relevant information for the task, or those that respond strongly to one sensory stimulus but weakly to its comparison stimulus. Current theories suggest this plasticity is caused when target stimulus evoked activity is enhanced by reward signals from neuromodulatory nuclei. Prior work has found evidence suggestive of nonselective enhancement of neural responses, and suppression of responses to task distractors, but the differences in these effects between detection and discrimination have not been directly tested. Using cortical implants, we defined physiological responses in macaque somatosensory cortex during serial, matched, detection and discrimination tasks. Nonselective increases in neural responsiveness were observed during detection learning. Suppression of responses to task distractors was observed during discrimination learning, and this suppression was specific to cortical locations that sampled responses to the task distractor before learning. Changes in receptive field size were measured as the area of skin that had a significant response to a constant magnitude stimulus, and these areal changes paralleled changes in responsiveness. From before detection learning until after discrimination learning, the enduring changes were selective suppression of cortical locations responsive to task distractors, and nonselective enhancement of responsiveness at cortical locations selective for target and control skin sites. A comparison of observations in prior studies with the observed plasticity effects suggests that the non-selective response enhancement and selective suppression suffice to explain known plasticity phenomena in simple spatial tasks. This work suggests that differential responsiveness to task targets and distractors in primary sensory cortex for a simple spatial detection and discrimination task arise from

  18. Perceptual load-dependent neural correlates of distractor interference inhibition.

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    Jiansong Xu

    2011-01-01

    Full Text Available The load theory of selective attention hypothesizes that distractor interference is suppressed after perceptual processing (i.e., in the later stage of central processing at low perceptual load of the central task, but in the early stage of perceptual processing at high perceptual load. Consistently, studies on the neural correlates of attention have found a smaller distractor-related activation in the sensory cortex at high relative to low perceptual load. However, it is not clear whether the distractor-related activation in brain regions linked to later stages of central processing (e.g., in the frontostriatal circuits is also smaller at high rather than low perceptual load, as might be predicted based on the load theory.We studied 24 healthy participants using functional magnetic resonance imaging (fMRI during a visual target identification task with two perceptual loads (low vs. high. Participants showed distractor-related increases in activation in the midbrain, striatum, occipital and medial and lateral prefrontal cortices at low load, but distractor-related decreases in activation in the midbrain ventral tegmental area and substantia nigra (VTA/SN, striatum, thalamus, and extensive sensory cortices at high load.Multiple levels of central processing involving midbrain and frontostriatal circuits participate in suppressing distractor interference at either low or high perceptual load. For suppressing distractor interference, the processing of sensory inputs in both early and late stages of central processing are enhanced at low load but inhibited at high load.

  19. Perceptual load-dependent neural correlates of distractor interference inhibition.

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    Xu, Jiansong; Monterosso, John; Kober, Hedy; Balodis, Iris M; Potenza, Marc N

    2011-01-18

    The load theory of selective attention hypothesizes that distractor interference is suppressed after perceptual processing (i.e., in the later stage of central processing) at low perceptual load of the central task, but in the early stage of perceptual processing at high perceptual load. Consistently, studies on the neural correlates of attention have found a smaller distractor-related activation in the sensory cortex at high relative to low perceptual load. However, it is not clear whether the distractor-related activation in brain regions linked to later stages of central processing (e.g., in the frontostriatal circuits) is also smaller at high rather than low perceptual load, as might be predicted based on the load theory. We studied 24 healthy participants using functional magnetic resonance imaging (fMRI) during a visual target identification task with two perceptual loads (low vs. high). Participants showed distractor-related increases in activation in the midbrain, striatum, occipital and medial and lateral prefrontal cortices at low load, but distractor-related decreases in activation in the midbrain ventral tegmental area and substantia nigra (VTA/SN), striatum, thalamus, and extensive sensory cortices at high load. Multiple levels of central processing involving midbrain and frontostriatal circuits participate in suppressing distractor interference at either low or high perceptual load. For suppressing distractor interference, the processing of sensory inputs in both early and late stages of central processing are enhanced at low load but inhibited at high load.

  20. The Rapid Perceptual Impact of Emotional Distractors.

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    Briana L Kennedy

    Full Text Available The brief presentation of an emotional distractor can temporarily impair perception of a subsequent, rapidly presented target, an effect known as emotion-induced blindness (EIB. How rapidly does this impairment unfold? To probe this question, we examined EIB for targets that immediately succeeded ("lag-1" emotional distractors in a rapid stream of items relative to EIB for targets at later serial positions. Experiments 1 and 2 suggested that emotional distractors interfere with items presented very soon after them, with impaired target perception emerging as early as lag-1. Experiment 3 included an exploratory examination of individual differences, which suggested that EIB onsets more rapidly among participants scoring high in measures linked to negative affect.

  1. The role of size constancy for the integration of local elements into a global shape

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    Johannes eRennig

    2013-07-01

    Full Text Available Visual perception depends on the visual context and is likely to be influenced by size constancy, which predicts a size and distance invariant perception of objects. However, size constancy can also result in optical illusions that allow the manipulation of the perceived size. We thus asked whether the integration of local elements into a global object can be influenced by manipulations of the visual context and size constancy? A set of stimuli was applied in healthy individuals that took advantage of the ‘Kanizsa’ illusion, in which three circles with open wedges oriented towards a center point are placed to form an illusionary perception of a triangle. In addition, a 3D-perspective view was implemented in which the global target (‘Kanizsa’ triangle was placed in combination with several distractor circles either in a close or a distant position. Subjects were engaged in a global recognition task on the location of the ‘Kanizsa’ triangle. Global recognition of ‘Kanizsa’ triangles improved with a decreasing length of the illusory contour. Interestingly, recognition of ‘Kanizsa’ triangles decreased when they were perceived as if they were located further away. We conclude that the integration of local elements into a global object is dependent on the visual context and dominated by size constancy.

  2. Distractor Inhibition: Principles of Operation during Selective Attention

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    Wyatt, Natalie; Machado, Liana

    2013-01-01

    Research suggests that although target amplification acts as the main determinant of the efficacy of selective attention, distractor inhibition contributes under some circumstances. Here we aimed to gain insight into the operating principles that regulate the use of distractor inhibition during selective attention. The results suggest that, in…

  3. Neural correlates of an early attentional capture by positive distractor words.

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    Hinojosa, José A; Mercado, Francisco; Albert, Jacobo; Barjola, Paloma; Peláez, Irene; Villalba-García, Cristina; Carretié, Luis

    2015-01-01

    Exogenous or automatic attention to emotional distractors has been observed for emotional scenes and faces. In the language domain, however, automatic attention capture by emotional words has been scarcely investigated. In the current event-related potentials study we explored distractor effects elicited by positive, negative and neutral words in a concurrent but distinct target distractor paradigm. Specifically, participants performed a digit categorization task in which task-irrelevant words were flanked by numbers. The results of both temporo-spatial principal component and source location analyses revealed the existence of early distractor effects that were specifically triggered by positive words. At the scalp level, task-irrelevant positive compared to neutral and negative words elicited larger amplitudes in an anterior negative component that peaked around 120 ms. Also, at the voxel level, positive distractor words increased activity in orbitofrontal regions compared to negative words. These results suggest that positive distractor words quickly and automatically capture attentional resources diverting them from the task where attention was voluntarily directed.

  4. Neural correlates of an early attentional capture by positive distractor words

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    José Antonio Hinojosa

    2015-01-01

    Full Text Available Exogenous or automatic attention to emotional distractors has been observed for emotional scenes and faces. In the language domain, however, automatic attention capture by emotional words has been scarcely investigated. In the current event-related potentials study we explored distractor effects elicited by positive, negative and neutral words in a concurrent but distinct target distractor paradigm. Specifically, participants performed a digit categorization task in which task-irrelevant words were flanked by numbers. The results of both temporo-spatial principal component and source location analyses revealed the existence of early distractor effects that were specifically triggered by positive words. At the scalp level, task-irrelevant positive compared to neutral and negative words elicited larger amplitudes in an anterior negative component that peaked around 120 ms. Also, at the voxel level, positive distractor words increased activity in orbitofrontal regions compared to negative words. These results suggest that positive distractor words quickly and automatically capture attentional resources diverting them from the task where attention was voluntarily directed.

  5. Congruency effects in the remote distractor paradigm: evidence for top-down modulation.

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    Born, Sabine; Kerzel, Dirk

    2009-08-10

    In three experiments, we examined effects of target-distractor similarity in the remote distractor effect (RDE). Observers made saccades to peripheral targets that were either gray or green. Foveal or peripheral distractors were presented at the same time. The distractors could either share the target's defining property (congruent) or be different from the target (incongruent). Congruent distractors slowed down saccadic reaction times more than incongruent distractors. The increase of the RDE with target-distractor congruency depended on task demands. The more participants had to rely on the target property to locate the target, the larger the congruency effect. We conclude that the RDE can be modulated in a top-down manner. Alternative explanations such as persisting memory traces for the target property or differences in stimulus arrangement were considered but discarded. Our claim is in line with models of saccade generation which assume that the structures underlying the RDE (e.g. the superior colliculus) receive bottom-up as well as top-down information.

  6. Rapid accumulation of inhibition accounts for saccades curved away from distractors.

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    Kehoe, Devin H; Fallah, Mazyar

    2017-08-01

    Saccades curved toward a distractor are accompanied by a burst of neuronal activation at the distractor locus in the intermediate layers of the superior colliculus (SCi) ~30 ms before the initiation of a saccade. Although saccades curve away from inactivated SCi loci, whether inhibition is restricted to a similar critical epoch for saccades curved away from a distractor remains unclear. We examined this possibility by modeling human saccade curvature as a function of the time between onset of a task irrelevant luminance- or color-modulated distractor and initiation of an impending saccade, referred to as saccade distractor onset asynchrony (SDOA). Our results demonstrated that 70 ms of luminance-modulated distractor processing or 90 ms of color-modulated distractor processing was required to modulate saccade trajectories. As these behavioral, feature-based differences were temporally consistent with the cortically mediated neurophysiological differences in visual onset latencies between luminance and color stimuli observed in the oculomotor and visual system, this method provides a noninvasive means to estimate the timing of peak activation in the oculomotor system. As such, we modeled SDOA functions separately for saccades curved toward and away from distractors and observed that a similar temporal process determined the magnitude of saccade curvatures in both contexts, suggesting that saccades deviate away from a distractor due to a rapid accumulation of inhibition in the critical epoch before saccade initiation. NEW & NOTEWORTHY In this research article, we propose a novel, noninvasive approach to behaviorally model the time course of competitive oculomotor processing. Our results highly resembled those from previously published neurophysiological experiments utilizing similar oculomotor processing contexts, thus validating our approach. Furthermore, this methodology provided new insights into the underlying neural mechanism subserving oculomotor processing

  7. Psychology of computer use: XXXII. Computer screen-savers as distractors.

    Science.gov (United States)

    Volk, F A; Halcomb, C G

    1994-12-01

    The differences in performance of 16 male and 16 female undergraduates on three cognitive tasks were investigated in the presence of visual distractors (computer-generated dynamic graphic images). These tasks included skilled and unskilled proofreading and listening comprehension. The visually demanding task of proofreading (skilled and unskilled) showed no significant decreases in performance in the distractor conditions. Results showed significant decrements, however, in performance on listening comprehension in at least one of the distractor conditions.

  8. Selective attention supports working memory maintenance by modulating perceptual processing of distractors.

    Science.gov (United States)

    Sreenivasan, Kartik K; Jha, Amishi P

    2007-01-01

    Selective attention has been shown to bias sensory processing in favor of relevant stimuli and against irrelevant or distracting stimuli in perceptual tasks. Increasing evidence suggests that selective attention plays an important role during working memory maintenance, possibly by biasing sensory processing in favor of to-be-remembered items. In the current study, we investigated whether selective attention may also support working memory by biasing processing against irrelevant and potentially distracting information. Event-related potentials (ERPs) were recorded while subjects (n = 22) performed a delayed-recognition task for faces and shoes. The delay period was filled with face or shoe distractors. Behavioral performance was impaired when distractors were congruent with the working memory domain (e.g., face distractor during working memory for faces) relative to when distractors were incongruent with the working memory domain (e.g., face distractor during shoe working memory). If attentional biasing against distractor processing is indeed functionally relevant in supporting working memory maintenance, perceptual processing of distractors is predicted to be attenuated when distractors are more behaviorally intrusive relative to when they are nonintrusive. As such, we predicted that perceptual processing of distracting faces, as measured by the face-sensitive N170 ERP component, would be reduced in the context of congruent (face) working memory relative to incongruent (shoe) working memory. The N170 elicited by distracting faces demonstrated reduced amplitude during congruent versus incongruent working memory. These results suggest that perceptual processing of distracting faces may be attenuated due to attentional biasing against sensory processing of distractors that are most behaviorally intrusive during working memory maintenance.

  9. Distractor inhibition predicts individual differences in recovery from the attentional blink.

    Directory of Open Access Journals (Sweden)

    Heleen A Slagter

    Full Text Available BACKGROUND: The attentional blink (AB refers to an impairment in detecting the second of two target stimuli presented in close succession in a rapid stream of distractors. Recent studies indicate that the AB results, in part, from distractor suppression mechanisms, that may be mediated by striatal dopamine. Yet, it is currently unclear how distractor suppression ability may contribute to the AB. Here, we examined whether distractor suppression ability is predictive of an individual's AB depth and/or recovery. In addition, we investigated the relationship between individual spontaneous eye blink rate (sEBR, a marker of striatal dopaminergic functioning, and AB performance. METHODOLOGY/PRINCIPAL FINDINGS: Subjects were presented with rapid streams of letters containing white distractors, a red T1 and a green T2. T2 was presented either at Lag2, Lag4 or Lag10, and preceded by a distractor that shared the same identity as T2 (T2 primed or not (T2 not primed. Replicating previous work [1], we found that slow AB recovery (poor T2 performance in Lag4 vs. Lag10 was associated with a failure to inhibit distractors, as indexed by greater positive priming. However, no relationship was observed between a subject's ability to suppress distractors and AB depth (Lag10 vs. Lag2. Moreover, no relationship between sEBR and AB performance was observed. RESULTS/SIGNIFICANCE: These results indicate that a failure to inhibit distracting information impairs AB recovery, possibly by interfering with target encoding in working memory - but does not affect AB magnitude. The absence of a relationship between individual sEBR and AB performance may be explained by task specifics.

  10. Breakage of internal maxillary distractor: considerable complication of maxillary distraction osteogenesis.

    Science.gov (United States)

    Aikawa, Tomonao; Iida, Seiji; Isomura, Emiko T; Namikawa, Mari; Matsuoka, Yudai; Yamada, Chiaki; Yamamoto, Taku; Takigawa, Yoko

    2008-07-01

    Maxillary distraction osteogenesis using intraoral distractors is now one of the standard treatments of maxillary retrusion. This report shows 2 cases of breakage of this internal maxillary distractor in patients with cleft lip and palate; one was observed during the distraction period and the other was during the retention period. The first case required a rotational movement of the distraction segment, and this movement caused the laterally dislocation of the posterior part of the distractor, where the distractor suffered some mechanical forces by mouth opening. In the latter case, breakage of distractor was observed on the radiographs taken 3 months after distraction and this complication may have been caused by mechanical force by occlusion and mastication. Both breakages were found at the joint of the anchorage plate and the extension rod, which has some flexibility for adjusting the plate to the bone surface. Therefore, surgeons should pay special attention for this mechanical weak area in this distractor not only during the advancement period, but also during the retention period and should avoid unnecessary frequent bending for adopting the bone surface, which directly weakens the joint.

  11. Control of information in working memory: Encoding and removal of distractors in the complex-span paradigm.

    Science.gov (United States)

    Oberauer, Klaus; Lewandowsky, Stephan

    2016-11-01

    The article reports four experiments with complex-span tasks in which encoding of memory items alternates with processing of distractors. The experiments test two assumptions of a computational model of complex span, SOB-CS: (1) distractor processing impairs memory because distractors are encoded into working memory, thereby interfering with memoranda; and (2) free time following distractors is used to remove them from working memory by unbinding their representations from list context. Experiment 1 shows that distractors are erroneously chosen for recall more often than not-presented stimuli, demonstrating that distractors are encoded into memory. Distractor intrusions declined with longer free time, as predicted by distractor removal. Experiment 2 shows these effects even when distractors precede the memory list, ruling out an account based on selective rehearsal of memoranda during free time. Experiments 3 and 4 test the notion that distractors decay over time. Both experiments show that, contrary to the notion of distractor decay, the chance of a distractor intruding at test does not decline with increasing time since encoding of that distractor. Experiment 4 provides additional evidence against the prediction from distractor decay that distractor intrusions decline over an unfilled retention interval. Taken together, the results support SOB-CS and rule out alternative explanations. Data and simulation code are available on Open Science Framework: osf.io/3ewh7. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Steady-state signatures of visual perceptual load, multimodal distractor filtering, and neural competition.

    Science.gov (United States)

    Parks, Nathan A; Hilimire, Matthew R; Corballis, Paul M

    2011-05-01

    The perceptual load theory of attention posits that attentional selection occurs early in processing when a task is perceptually demanding but occurs late in processing otherwise. We used a frequency-tagged steady-state evoked potential paradigm to investigate the modality specificity of perceptual load-induced distractor filtering and the nature of neural-competitive interactions between task and distractor stimuli. EEG data were recorded while participants monitored a stream of stimuli occurring in rapid serial visual presentation (RSVP) for the appearance of previously assigned targets. Perceptual load was manipulated by assigning targets that were identifiable by color alone (low load) or by the conjunction of color and orientation (high load). The RSVP task was performed alone and in the presence of task-irrelevant visual and auditory distractors. The RSVP stimuli, visual distractors, and auditory distractors were "tagged" by modulating each at a unique frequency (2.5, 8.5, and 40.0 Hz, respectively), which allowed each to be analyzed separately in the frequency domain. We report three important findings regarding the neural mechanisms of perceptual load. First, we replicated previous findings of within-modality distractor filtering and demonstrated a reduction in visual distractor signals with high perceptual load. Second, auditory steady-state distractor signals were unaffected by manipulations of visual perceptual load, consistent with the idea that perceptual load-induced distractor filtering is modality specific. Third, analysis of task-related signals revealed that visual distractors competed with task stimuli for representation and that increased perceptual load appeared to resolve this competition in favor of the task stimulus.

  13. Neural correlates of an early attentional capture by positive distractor words

    OpenAIRE

    Hinojosa, Jos? A.; Mercado, Francisco; Albert, Jacobo; Barjola, Paloma; Pel?ez, Irene; Villalba-Garc?a, Cristina; Carreti?, Luis

    2015-01-01

    Exogenous or automatic attention to emotional distractors has been observed for emotional scenes and faces. In the language domain, however, automatic attention capture by emotional words has been scarcely investigated. In the current event-related potentials study we explored distractor effects elicited by positive, negative and neutral words in a concurrent but distinct target distractor paradigm. Specifically, participants performed a digit categorization task in which task-irrelevant words...

  14. Neural correlates of an early attentional capture by positive distractor words

    OpenAIRE

    José Antonio Hinojosa; Francisco eMercado; Jacobo eAlbert; Jacobo eAlbert; Paloma eBarjola; Irene ePeláez; Cristina eVillalba-García; Luis eCarretié

    2015-01-01

    Exogenous or automatic attention to emotional distractors has been observed for emotional scenes and faces. In the language domain, however, automatic attention capture by emotional words has been scarcely investigated. In the current event-related potentials study we explored distractor effects elicited by positive, negative and neutral words in a concurrent but distinct target distractor paradigm. Specifically, participants performed a digit categorization task in which task-irrelevant wor...

  15. Focal Suppression of Distractor Sounds by Selective Attention in Auditory Cortex.

    Science.gov (United States)

    Schwartz, Zachary P; David, Stephen V

    2018-01-01

    Auditory selective attention is required for parsing crowded acoustic environments, but cortical systems mediating the influence of behavioral state on auditory perception are not well characterized. Previous neurophysiological studies suggest that attention produces a general enhancement of neural responses to important target sounds versus irrelevant distractors. However, behavioral studies suggest that in the presence of masking noise, attention provides a focal suppression of distractors that compete with targets. Here, we compared effects of attention on cortical responses to masking versus non-masking distractors, controlling for effects of listening effort and general task engagement. We recorded single-unit activity from primary auditory cortex (A1) of ferrets during behavior and found that selective attention decreased responses to distractors masking targets in the same spectral band, compared with spectrally distinct distractors. This suppression enhanced neural target detection thresholds, suggesting that limited attention resources serve to focally suppress responses to distractors that interfere with target detection. Changing effort by manipulating target salience consistently modulated spontaneous but not evoked activity. Task engagement and changing effort tended to affect the same neurons, while attention affected an independent population, suggesting that distinct feedback circuits mediate effects of attention and effort in A1. © The Author 2017. Published by Oxford University Press.

  16. Bounded elements in Locally C*-algebras

    International Nuclear Information System (INIS)

    El Harti, Rachid

    2001-09-01

    In order to get more useful information about Locally C*-algebras, we introduce in this paper the notion of bounded elements. First, we study the connection between bounded elements and spectrally bounded elements. Some structural results of Locally C*-algebras are established in Theorems 1 , 2 and 3. As an immediate consequence of Theorem 3, we give a characterization of the connected component of the identity in the group of unitary elements for a Locally C*-algebra. (author)

  17. Development of visual working memory and distractor resistance in relation to academic performance.

    Science.gov (United States)

    Tsubomi, Hiroyuki; Watanabe, Katsumi

    2017-02-01

    Visual working memory (VWM) enables active maintenance of goal-relevant visual information in a readily accessible state. The storage capacity of VWM is severely limited, often as few as 3 simple items. Thus, it is crucial to restrict distractor information from consuming VWM capacity. The current study investigated how VWM storage and distractor resistance develop during childhood in relation to academic performance in the classroom. Elementary school children (7- to 12-year-olds) and adults (total N=140) completed a VWM task with and without visual/verbal distractors during the retention period. The results showed that VWM performance with and without distractors developed at similar rates until reaching adult levels at 10years of age. In addition, higher VWM performance without distractors was associated with higher academic scores in literacy (reading and writing), mathematics, and science for the younger children (7- to 9-year-olds), whereas these academic scores for the older children (10- to 12-year-olds) were associated with VWM performance with visual distractors. Taken together, these results suggest that VWM storage and distractor resistance develop at a similar rate, whereas their contributions to academic performance differ with age. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Distractor dwelling, skipping, and revisiting determine target absent performance in difficult visual search

    Directory of Open Access Journals (Sweden)

    Gernot Horstmann

    2016-08-01

    Full Text Available Some targets in visual search are more difficult to find than others. In particular, a target that is similar to the distractors is more difficult to find than a target that is dissimilar to the distractors. Efficiency differences between easy and difficult searches are manifest not only in target-present trials but also in target-absent trials. In fact, even physically identical displays are searched through with different efficiency depending on the searched-for target. Here, we monitored eye movements in search for a target similar to the distractors (difficult search versus a target dissimilar to the distractors (easy search. We aimed to examine three hypotheses concerning the causes of differential search efficiencies in target-absent trials: (a distractor dwelling (b distractor skipping, and (c distractor revisiting. Reaction times increased with target similarity which is consistent with existing theories and replicates earlier results. Eye movement data indicated guidance in target trials, even though search was very slow. Dwelling, skipping, and revisiting contributed to low search efficiency in difficult search, with dwelling being the strongest factor. It is argued that differences in dwell time account for a large amount of total search time differences.

  19. Distractor Dwelling, Skipping, and Revisiting Determine Target Absent Performance in Difficult Visual Search

    Science.gov (United States)

    Horstmann, Gernot; Herwig, Arvid; Becker, Stefanie I.

    2016-01-01

    Some targets in visual search are more difficult to find than others. In particular, a target that is similar to the distractors is more difficult to find than a target that is dissimilar to the distractors. Efficiency differences between easy and difficult searches are manifest not only in target-present trials but also in target-absent trials. In fact, even physically identical displays are searched through with different efficiency depending on the searched-for target. Here, we monitored eye movements in search for a target similar to the distractors (difficult search) versus a target dissimilar to the distractors (easy search). We aimed to examine three hypotheses concerning the causes of differential search efficiencies in target-absent trials: (a) distractor dwelling (b) distractor skipping, and (c) distractor revisiting. Reaction times increased with target similarity which is consistent with existing theories and replicates earlier results. Eye movement data indicated guidance in target trials, even though search was very slow. Dwelling, skipping, and revisiting contributed to low search efficiency in difficult search, with dwelling being the strongest factor. It is argued that differences in dwell time account for a large amount of total search time differences. PMID:27574510

  20. Dissociating distractor inhibition and episodic retrieval processes in children: No evidence for developmental deficits.

    Science.gov (United States)

    Giesen, Carina; Weissmann, Francesca; Rothermund, Klaus

    2018-02-01

    It is often assumed that children show reduced or absent inhibition of distracting material due to pending cognitive maturation, although empirical findings do not provide strong support for the idea of an "inhibitory deficit" in children. Most of this evidence, however, is based on findings from the negative priming paradigm, which confounds distractor inhibition and episodic retrieval processes. To resolve this confound, we adopted a sequential distractor repetition paradigm of Giesen, Frings, and Rothermund (2012), which provides independent estimates of distractor inhibition and episodic retrieval processes. Children (aged 7-9years) and young adults (aged 18-29years) identified centrally presented target fruit stimuli among two flanking distractor fruits that were always response incompatible. Children showed both reliable distractor inhibition effects as well as robust episodic retrieval effects of distractor-response bindings. Age group comparisons suggest that processes of distractor inhibition and episodic retrieval are already present and functionally intact in children and are comparable to those of young adults. The current findings highlight that the sequential distractor repetition paradigm of Giesen et al. (2012) is a versatile tool to investigate distractor inhibition and episodic retrieval separately and in an unbiased way and is also of merit for the examination of age differences with regard to these processes. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Entirely irrelevant distractors can capture and captivate attention.

    Science.gov (United States)

    Forster, Sophie; Lavie, Nilli

    2011-12-01

    The question of whether a stimulus onset may capture attention when it is entirely irrelevant to the task and even in the absence of any attentional settings for abrupt onset or any dynamic changes has been highly controversial. In the present study, we designed a novel irrelevant capture task to address this question. Participants engaged in a continuous task making sequential forced choice (letter or digit) responses to each item in an alphanumeric matrix that remained on screen throughout many responses. This task therefore involved no attentional settings for onset or indeed any dynamic changes, yet the brief onset of an entirely irrelevant distractor (a cartoon picture) resulted in significant slowing of the two (Experiment 1) or three (Experiment 2) responses immediately following distractor appearance These findings provide a clear demonstration of attention being captured and captivated by a distractor that is entirely irrelevant to any attentional settings of the task.

  2. Looking away: distractor influences on saccadic trajectory and endpoint in prosaccade and antisaccade tasks.

    Science.gov (United States)

    Laidlaw, Kaitlin E W; Zhu, Mona J H; Kingstone, Alan

    2016-06-01

    Successful target selection often occurs concurrently with distractor inhibition. A better understanding of the former thus requires a thorough study of the competition that arises between target and distractor representations. In the present study, we explore whether the presence of a distractor influences saccade processing via interfering with visual target and/or saccade goal representations. To do this, we asked participants to make either pro- or antisaccade eye movements to a target and measured the change in their saccade trajectory and landing position (collectively referred to as deviation) in response to distractors placed near or far from the saccade goal. The use of an antisaccade paradigm may help to distinguish between stimulus- and goal-related distractor interference, as unlike with prosaccades, these two features are dissociated in space when making a goal-directed antisaccade response away from a visual target stimulus. The present results demonstrate that for both pro- and antisaccades, distractors near the saccade goal elicited the strongest competition, as indicated by greater saccade trajectory deviation and landing position error. Though distractors far from the saccade goal elicited, on average, greater deviation away in antisaccades than in prosaccades, a time-course analysis revealed a significant effect of far-from-goal distractors in prosaccades as well. Considered together, the present findings support the view that goal-related representations most strongly influence the saccade metrics tested, though stimulus-related representations may play a smaller role in determining distractor-based interference effects on saccade execution under certain circumstances. Further, the results highlight the advantage of considering temporal changes in distractor-based interference.

  3. An assessment of functioning and non-functioning distractors in multiple-choice questions: a descriptive analysis.

    Science.gov (United States)

    Tarrant, Marie; Ware, James; Mohammed, Ahmed M

    2009-07-07

    Four- or five-option multiple choice questions (MCQs) are the standard in health-science disciplines, both on certification-level examinations and on in-house developed tests. Previous research has shown, however, that few MCQs have three or four functioning distractors. The purpose of this study was to investigate non-functioning distractors in teacher-developed tests in one nursing program in an English-language university in Hong Kong. Using item-analysis data, we assessed the proportion of non-functioning distractors on a sample of seven test papers administered to undergraduate nursing students. A total of 514 items were reviewed, including 2056 options (1542 distractors and 514 correct responses). Non-functioning options were defined as ones that were chosen by fewer than 5% of examinees and those with a positive option discrimination statistic. The proportion of items containing 0, 1, 2, and 3 functioning distractors was 12.3%, 34.8%, 39.1%, and 13.8% respectively. Overall, items contained an average of 1.54 (SD = 0.88) functioning distractors. Only 52.2% (n = 805) of all distractors were functioning effectively and 10.2% (n = 158) had a choice frequency of 0. Items with more functioning distractors were more difficult and more discriminating. The low frequency of items with three functioning distractors in the four-option items in this study suggests that teachers have difficulty developing plausible distractors for most MCQs. Test items should consist of as many options as is feasible given the item content and the number of plausible distractors; in most cases this would be three. Item analysis results can be used to identify and remove non-functioning distractors from MCQs that have been used in previous tests.

  4. Impaired Attentional Control in Pedophiles in a Sexual Distractor Task

    Science.gov (United States)

    Jordan, Kirsten; Fromberger, Peter; von Herder, Jakob; Steinkrauss, Henrike; Nemetschek, Rebekka; Witzel, Joachim; Müller, Jürgen L.

    2016-01-01

    Pedophilic disorder, a subtype of paraphilia, is defined as a recurrent sexual interest in prepubescent children, which is characterized by persistent thoughts, fantasies, urges, sexual arousal, or behavior. Besides a deviant sexual preference, sexual preoccupation was found to be a dynamic risk factor for reoffending. Thus, it is conceivable that sex offenders and especially sex offenders against children have difficulties to control their responses to sexual stimuli. In the current study pedophiles, forensic and non-forensic control subjects had to solve a cognitive task, while sexual distractors were presented simultaneously. This kind of task also requires control functions. Therefore, data were analyzed with respect to attentional control while comparing eye movements toward sexual distractors and toward the cognitive task. We were mainly interested in how early (fixation latency) and late (relative fixation time) attentional processes were allocated to both, the cognitive target stimuli and the sexual distractors. Pedophiles demonstrated significantly lower attentional control in the sexual distractor task than both control groups (non-pedophiles). They showed a shorter fixation latency and longer fixation time for sexual distractors than non-pedophiles. Furthermore, pedophiles demonstrated a longer fixation latency and shorter fixation time for cognitive target stimuli. For classification analyses, an attentional control index (ACI) was built, i.e., the difference between eye movements on cognitive target stimuli and sexual distractors. For the ACI of early attentional processes, i.e., fixation latency, a good classification between pedophiles and non-pedophiles was found. We assumed that the measured attentional control represents inhibitory executive functions, specifically interference control. Further studies should examine if low attentional control in pedophiles is due to low motivation to solve the task or rather to a lack of ability to control

  5. An assessment of functioning and non-functioning distractors in multiple-choice questions: a descriptive analysis

    Directory of Open Access Journals (Sweden)

    Mohammed Ahmed M

    2009-07-01

    Full Text Available Abstract Background Four- or five-option multiple choice questions (MCQs are the standard in health-science disciplines, both on certification-level examinations and on in-house developed tests. Previous research has shown, however, that few MCQs have three or four functioning distractors. The purpose of this study was to investigate non-functioning distractors in teacher-developed tests in one nursing program in an English-language university in Hong Kong. Methods Using item-analysis data, we assessed the proportion of non-functioning distractors on a sample of seven test papers administered to undergraduate nursing students. A total of 514 items were reviewed, including 2056 options (1542 distractors and 514 correct responses. Non-functioning options were defined as ones that were chosen by fewer than 5% of examinees and those with a positive option discrimination statistic. Results The proportion of items containing 0, 1, 2, and 3 functioning distractors was 12.3%, 34.8%, 39.1%, and 13.8% respectively. Overall, items contained an average of 1.54 (SD = 0.88 functioning distractors. Only 52.2% (n = 805 of all distractors were functioning effectively and 10.2% (n = 158 had a choice frequency of 0. Items with more functioning distractors were more difficult and more discriminating. Conclusion The low frequency of items with three functioning distractors in the four-option items in this study suggests that teachers have difficulty developing plausible distractors for most MCQs. Test items should consist of as many options as is feasible given the item content and the number of plausible distractors; in most cases this would be three. Item analysis results can be used to identify and remove non-functioning distractors from MCQs that have been used in previous tests.

  6. Music and speech distractors disrupt sensorimotor synchronization: effects of musical training.

    Science.gov (United States)

    Białuńska, Anita; Dalla Bella, Simone

    2017-12-01

    Humans display a natural tendency to move to the beat of music, more than to the rhythm of any other auditory stimulus. We typically move with music, but rarely with speech. This proclivity is apparent early during development and can be further developed over the years via joint dancing, singing, or instrument playing. Synchronization of movement to the beat can thus improve with age, but also with musical experience. In a previous study, we found that music perturbed synchronization with a metronome more than speech fragments; music superiority disappeared when distractors shared isochrony and the same meter (Dalla Bella et al., PLoS One 8(8):e71945, 2013). Here, we examined if the interfering effect of music and speech distractors in a synchronization task is influenced by musical training. Musicians and non-musicians synchronized by producing finger force pulses to the sounds of a metronome while music and speech distractors were presented at one of various phase relationships with respect to the target. Distractors were familiar musical excerpts and fragments of children poetry comparable in terms of beat/stress isochrony. Music perturbed synchronization with the metronome more than speech did in both groups. However, the difference in synchronization error between music and speech distractors was smaller for musicians than for non-musicians, especially when the peak force of movement is reached. These findings point to a link between musical training and timing of sensorimotor synchronization when reacting to music and speech distractors.

  7. Role of Frontal Cortex in Attentional Capture by Singleton Distractors

    Science.gov (United States)

    de Fockert, Jan W.; Theeuwes, Jan

    2012-01-01

    The role of frontal cortex in selective attention to visual distractors was examined in an attentional capture task in which participants searched for a unique shape in the presence or absence of an additional colour singleton distractor. The presence of the additional singleton was associated with slower behavioural responses to the shape target,…

  8. When increasing distraction helps learning: Distractor number and content interact in their effects on memory.

    Science.gov (United States)

    Nussenbaum, Kate; Amso, Dima; Markant, Julie

    2017-11-01

    Previous work has demonstrated that increasing the number of distractors in a search array can reduce interference from distractor content during target processing. However, it is unclear how this reduced interference influences learning of target information. Here, we investigated how varying the amount and content of distraction present in a learning environment affects visual search and subsequent memory for target items. In two experiments, we demonstrate that the number and content of competing distractors interact in their influence on target selection and memory. Specifically, while increasing the number of distractors present in a search array made target detection more effortful, it did not impair learning and memory for target content. Instead, when the distractors contained category information that conflicted with the target, increasing the number of distractors from one to three actually benefitted learning and memory. These data suggest that increasing numbers of distractors may reduce interference from conflicting conceptual information during encoding.

  9. Semantic interference from distractor pictures in single-picture naming: evidence for competitive lexical selection.

    Science.gov (United States)

    Jescheniak, Jörg D; Matushanskaya, Asya; Mädebach, Andreas; Müller, Matthias M

    2014-10-01

    Picture-naming studies have demonstrated interference from semantic-categorically related distractor words, but not from corresponding distractor pictures, and the lack of generality of the interference effect has been argued to challenge theories viewing lexical selection in speech production as a competitive process. Here, we demonstrate that semantic interference from context pictures does become visible, if sufficient attention is allocated to them. We combined picture naming with a spatial-cuing procedure. When participants' attention was shifted to the distractor, semantically related distractor pictures interfered with the response, as compared with unrelated distractor pictures. This finding supports models conceiving lexical retrieval as competitive (Levelt, Roelofs, & Meyer, 1999) but is difficult to reconcile with the response exclusion hypothesis (Finkbeiner & Caramazza, 2006b) proposed as an alternative.

  10. Selective Attention and Distractor Frequency in Naming Performance: Comment on Dhooge and Hartsuiker (2010)

    Science.gov (United States)

    Roelofs, Ardi; Piai, Vitoria; Schriefers, Herbert

    2011-01-01

    E. Dhooge and R. J. Hartsuiker (2010) reported experiments showing that picture naming takes longer with low- than high-frequency distractor words, replicating M. Miozzo and A. Caramazza (2003). In addition, they showed that this distractor-frequency effect disappears when distractors are masked or preexposed. These findings were taken to refute…

  11. Opposite effects of capacity load and resolution load on distractor processing.

    Science.gov (United States)

    Zhang, Weiwei; Luck, Steven J

    2015-02-01

    According to the load theory of attention, an increased perceptual load reduces distractor processing whereas an increased working memory load facilitates distractor processing. Here we raise the possibility that the critical distinction may instead be between an emphasis on resolution and an emphasis on capacity. That is, perceptual load manipulations typically emphasize resolution (fine-grained discriminations), whereas working memory load manipulations typically emphasize capacity (simultaneous processing of multiple relevant stimuli). To test the plausibility of this hypothesis, we used a visual working memory task that emphasized either the number of items to be stored (capacity load, retaining 2 vs. 4 colors) or the precision of the representations (resolution load, detecting small vs. large color changes). We found that an increased capacity load led to increased flanker interference (a measure of distractor processing), whereas an increased resolution load led to reduced flanker interference. These opposite effects of capacity load and resolution load on distractor processing mirror the previously described opposite effects of perceptual load and working memory load.

  12. Endogenous attention modulates attentional and motor interference from distractors: Evidence from behavioral and electrophysiological results.

    Directory of Open Access Journals (Sweden)

    Elisa eMartín-Arévalo

    2015-02-01

    Full Text Available Selective visual attention enhances the processing of relevant stimuli and filters out irrelevant stimuli and/or distractors. However, irrelevant information is sometimes processed, as demonstrated by the Simon effect (Simon & Rudell, 1967. We examined whether fully irrelevant distractors (task and target-irrelevant produce interference (measured as the Simon effect, and whether endogenous orienting modulated this interference. Despite being fully irrelevant, distractors were attentionally coded (as reflected by the distractor-related N2pc component, and interfered with the processing of the target response (as reflected by the target-related LRP component. Distractor’s attentional capture depended on endogenous attention, and their interference with target responses was modulated by both endogenous attention and distractor location repetition. These results demonstrate both endogenous attentional and motor modulations over the Simon effect produced by fully irrelevant distractors.

  13. The attentional white bear phenomenon: the mandatory allocation of attention to expected distractor locations.

    Science.gov (United States)

    Tsal, Yehoshua; Makovski, Tal

    2006-04-01

    The authors devised a prestimulus-probe method to assess the allocation of attention as a function of participants' top-down expectancies concerning distractor and target locations. Participants performed the flanker task, and distractor locations remained fixed. On some trials, instead of the flanker display, either 2 simultaneous dots or a horizontal line appeared. The dot in the expected distractor location was perceived to occur before the dot in the expected empty location, and the line appeared to extend from the expected distractor location to the expected empty location, suggesting that attention is allocated to expected distractor locations prior to stimulus onset. The authors propose that a process-all mechanism guides attention to expected locations of all stimuli regardless of task demands and that this constitutes a major cause for failures of selective attention.

  14. Contingent orienting or contingent capture: a size singleton matching the target-distractor size relation cannot capture attention.

    Science.gov (United States)

    Du, Feng; Yin, Yue; Qi, Yue; Zhang, Kan

    2014-08-01

    In the present study, we examined whether a peripheral size-singleton distractor that matches the target-distractor size relation can capture attention and disrupt central target identification. Three experiments consistently showed that a size singleton that matches the target-distractor size relation cannot capture attention when it appears outside of the attentional window, even though the same size singleton produces a cuing effect. In addition, a color singleton that matches the target color, instead of a size singleton that matches the target-distractor size relation, captures attention when it is outside of the attentional window. Thus, a size-relation-matched distractor is much weaker than a color-matched distractor in capturing attention and cannot capture attention when the distractor appears outside of the attentional window.

  15. Attentional Capture to a Singleton Distractor Degrades Visual Marking in Visual Search

    Directory of Open Access Journals (Sweden)

    Kenji Yamauchi

    2017-05-01

    Full Text Available Visual search is easier after observing some distractors in advance; it is as if the previewed distractors were excluded from the search. This effect is referred to as the preview benefit, and a memory template that visually marks the old locations of the distractors is thought to help in prioritizing the locations of newly presented items. One remaining question is whether the presence of a conspicuous item during the sequential shift of attention within the new items reduces this preview benefit. To address this issue, we combined the above preview search and a conventional visual search paradigm using a singleton distractor and examined whether the search performance was affected by the presence of the singleton. The results showed that the slope of reaction time as a function of set size became steeper in the presence of a singleton, indicating that the singleton distractor reduced the preview benefit. Furthermore, this degradation effect was positively correlated with the degree of conventional attentional capture to a singleton measured in a separate experiment with simultaneous search. These findings suggest that the mechanism of visual marking shares common attentional resources with the search process.

  16. Developmental trends in the facilitation of multisensory objects with distractors

    Directory of Open Access Journals (Sweden)

    Harriet eDowning

    2015-01-01

    Full Text Available Sensory integration and the ability to discriminate target objects from distractors are critical to survival, yet the developmental trajectories of these abilities are unknown. This study investigated developmental changes in 9- (n=18 and 11-year-old (n=20 children, adolescents (n=19 and adults (n=22 using an audiovisual object discrimination task with uni- and multisensory distractors. Reaction times (RTs were slower with visual/audiovisual distractors, and although all groups demonstrated facilitation of multisensory RTs in these conditions, children’s and adolescents’ responses corresponded to fewer race model violations than adults’, suggesting protracted maturation of multisensory processes. Multisensory facilitation could not be explained by changes in RT variability, suggesting that tests of race model violations may still have theoretical value at least for familiar multisensory stimuli.

  17. Interference between Maintenance and Processing in Working Memory: The Effect of Item-Distractor Similarity in Complex Span

    Science.gov (United States)

    Oberauer, Klaus; Farrell, Simon; Jarrold, Christopher; Pasiecznik, Kazimir; Greaves, Martin

    2012-01-01

    Four experiments examined the effect of phonological similarity between items and distractors on complex span performance. Item-distractor similarity benefited serial recall when distractors followed the items they were similar to, but not when distractors preceded the items they were similar to. These findings are predicted by C-SOB (contextual…

  18. Task-irrelevant distractors in the delay period interfere selectively with visual short-term memory for spatial locations.

    Science.gov (United States)

    Marini, Francesco; Scott, Jerry; Aron, Adam R; Ester, Edward F

    2017-07-01

    Visual short-term memory (VSTM) enables the representation of information in a readily accessible state. VSTM is typically conceptualized as a form of "active" storage that is resistant to interference or disruption, yet several recent studies have shown that under some circumstances task-irrelevant distractors may indeed disrupt performance. Here, we investigated how task-irrelevant visual distractors affected VSTM by asking whether distractors induce a general loss of remembered information or selectively interfere with memory representations. In a VSTM task, participants recalled the spatial location of a target visual stimulus after a delay in which distractors were presented on 75% of trials. Notably, the distractor's eccentricity always matched the eccentricity of the target, while in the critical conditions the distractor's angular position was shifted either clockwise or counterclockwise relative to the target. We then computed estimates of recall error for both eccentricity and polar angle. A general interference model would predict an effect of distractors on both polar angle and eccentricity errors, while a selective interference model would predict effects of distractors on angle but not on eccentricity errors. Results showed that for stimulus angle there was an increase in the magnitude and variability of recall errors. However, distractors had no effect on estimates of stimulus eccentricity. Our results suggest that distractors selectively interfere with VSTM for spatial locations.

  19. Altering spatial priority maps via statistical learning of target selection and distractor filtering.

    Science.gov (United States)

    Ferrante, Oscar; Patacca, Alessia; Di Caro, Valeria; Della Libera, Chiara; Santandrea, Elisa; Chelazzi, Leonardo

    2018-05-01

    The cognitive system has the capacity to learn and make use of environmental regularities - known as statistical learning (SL), including for the implicit guidance of attention. For instance, it is known that attentional selection is biased according to the spatial probability of targets; similarly, changes in distractor filtering can be triggered by the unequal spatial distribution of distractors. Open questions remain regarding the cognitive/neuronal mechanisms underlying SL of target selection and distractor filtering. Crucially, it is unclear whether the two processes rely on shared neuronal machinery, with unavoidable cross-talk, or they are fully independent, an issue that we directly addressed here. In a series of visual search experiments, participants had to discriminate a target stimulus, while ignoring a task-irrelevant salient distractor (when present). We systematically manipulated spatial probabilities of either one or the other stimulus, or both. We then measured performance to evaluate the direct effects of the applied contingent probability distribution (e.g., effects on target selection of the spatial imbalance in target occurrence across locations) as well as its indirect or "transfer" effects (e.g., effects of the same spatial imbalance on distractor filtering across locations). By this approach, we confirmed that SL of both target and distractor location implicitly bias attention. Most importantly, we described substantial indirect effects, with the unequal spatial probability of the target affecting filtering efficiency and, vice versa, the unequal spatial probability of the distractor affecting target selection efficiency across locations. The observed cross-talk demonstrates that SL of target selection and distractor filtering are instantiated via (at least partly) shared neuronal machinery, as further corroborated by strong correlations between direct and indirect effects at the level of individual participants. Our findings are compatible

  20. Phase attraction in sensorimotor synchronization with auditory sequences: effects of single and periodic distractors on synchronization accuracy.

    Science.gov (United States)

    Repp, Bruno H

    2003-04-01

    Four experiments showed that both single and periodic distractor tones affected the timing of finger taps produced in synchrony with an isochronous auditory target sequence. Single distractors had only small effects, but periodic distractors occurring at various fixed or changing phase relationships exerted strong phase attraction. The attraction was asymmetric, being stronger when distractors preceded target tones than when they lagged behind. A large pitch difference between target and distractor tones (20 vs. 3 semitones) did not reduce phase attraction substantially, although in the case of continuously changing phase relationships it did prevent complete capture of the taps by the distractors. The results support the hypothesis that phase attraction is an automatic process that is sensitive primarily to event onsets.

  1. A Single Unexpected Change in Target- but Not Distractor Motion Impairs Multiple Object Tracking

    Directory of Open Access Journals (Sweden)

    Hauke S. Meyerhoff

    2013-02-01

    Full Text Available Recent research addresses the question whether motion information of multiple objects contributes to maintaining a selection of objects across a period of motion. Here, we investigate whether target and/or distractor motion information is used during attentive tracking. We asked participants to track four objects and changed either the motion direction of targets, the motion direction of distractors, neither, or both during a brief flash in the middle of a tracking interval. We observed that a single direction change of targets is sufficient to impair tracking performance. In contrast, changing the motion direction of distractors had no effect on performance. This indicates that target- but not distractor motion information is evaluated during tracking.

  2. How to inhibit a distractor location? Statistical learning versus active, top-down suppression.

    Science.gov (United States)

    Wang, Benchi; Theeuwes, Jan

    2018-05-01

    Recently, Wang and Theeuwes (Journal of Experimental Psychology: Human Perception and Performance, 44(1), 13-17, 2018a) demonstrated the role of lingering selection biases in an additional singleton search task in which the distractor singleton appeared much more often in one location than in all other locations. For this location, there was less capture and selection efficiency was reduced. It was argued that statistical learning induces plasticity within the spatial priority map such that particular locations that are high likely to contain a distractor are suppressed relative to all other locations. The current study replicated these findings regarding statistical learning (Experiment 1) and investigated whether similar effects can be obtained by cueing the distractor location in a top-down way on a trial-by-trial basis. The results show that top-down cueing of the distractor location with long (1,500 ms; Experiment 2) and short stimulus-onset symmetries (SOAs) (600 ms; Experiment 3) does not result in suppression: The amount of capture nor the efficiency of selection was affected by the cue. If anything, we found an attentional benefit (instead of the suppression) for the short SOA. We argue that through statistical learning, weights within the attentional priority map are changed such that one location containing a salient distractor is suppressed relative to all other locations. Our cueing experiments show that this effect cannot be accomplished by active, top-down suppression. Consequences for recent theories of distractor suppression are discussed.

  3. Social exclusion impairs distractor suppression but not target enhancement in selective attention.

    Science.gov (United States)

    Xu, Mengsi; Li, Zhiai; Diao, Liuting; Fan, Lingxia; Zhang, Lijie; Yuan, Shuge; Yang, Dong

    2017-11-01

    Social exclusion has been thought to weaken one's ability to exert inhibitory control. Existing studies have primarily focused on the relationship between exclusion and behavioral inhibition, and have reported that exclusion impairs behavioral inhibition. However, whether exclusion also affects selective attention, another important aspect of inhibitory control, remains unknown. Therefore, the current study aimed to explore whether social exclusion impairs selective attention, and to specifically examine its effect on two hypothesized mechanisms of selective attention: target enhancement and distractor suppression. The Cyberball game was used to manipulate social exclusion. Participants then performed a visual search task while event-related potentials were recorded. In the visual search task, target and salient distractor were either both presented laterally or one was presented on the vertical midline and the other laterally. Results showed that social exclusion differentially affected target and distractor processing. While exclusion impaired distractor suppression, reflected as smaller distractor-positivity (Pd) amplitudes for the exclusion group compared to the inclusion group, it did not affect target enhancement, reflected as similar target-negativity (Nt) amplitudes for both the exclusion and inclusion groups. Together, these results extend our understanding of the relationship between exclusion and inhibitory control, and suggest that social exclusion affects selective attention in a more complex manner than previously thought. Copyright © 2017. Published by Elsevier B.V.

  4. Impaired distractor inhibition on a selective attention task in unmedicated, depressed subjects.

    Science.gov (United States)

    MacQueen, G M; Tipper, S P; Young, L T; Joffe, R T; Levitt, A J

    2000-05-01

    Impaired distractor inhibition may contribute to the selective attention deficits observed in depressed patients, but studies to date have not tested the distractor inhibition theory against the possibility that processes such as transient memory review processes may account for the observed deficits. A negative priming paradigm can dissociate inhibition from such a potentially confounding process called object review. The negative priming task also isolates features of the distractor such as colour and location for independent examination. A computerized negative priming task was used in which colour, identification and location features of a stimulus and distractor were systematically manipulated across successive prime and probe trials. Thirty-two unmedicated subjects with DSM-IV diagnoses of non-psychotic unipolar depression were compared with 32 age, sex and IQ matched controls. Depressed subjects had reduced levels of negative priming for conditions where the colour feature of the stimulus was repeated across prime and probe trials but not when identity or location was the repeated feature. When both the colour and location feature were the repeated feature across trials, facilitation in response was apparent. The pattern of results supports studies that found reduced distractor inhibition in depressed subjects, and suggests that object review is intact in these subjects. Greater impairment in negative priming for colour versus location suggests that subjects may have greater impairment in the visual stream associated with processing colour features.

  5. Opposite Effects of Capacity Load and Resolution Load on Distractor Processing

    OpenAIRE

    Zhang, Weiwei; Luck, Steven J.

    2014-01-01

    According to the load theory of attention, an increased perceptual load reduces distractor processing whereas an increased working memory load facilitates distractor processing. Here we raise the possibility that the critical distinction may instead be between an emphasis on resolution and an emphasis on capacity. That is, perceptual load manipulations typically emphasize resolution (fine-grained discriminations), whereas working memory load manipulations typically emphasize capacity (simulta...

  6. Phonological processing of ignored distractor pictures, an fMRI investigation.

    Science.gov (United States)

    Bles, Mart; Jansma, Bernadette M

    2008-02-11

    Neuroimaging studies of attention often focus on interactions between stimulus representations and top-down selection mechanisms in visual cortex. Less is known about the neural representation of distractor stimuli beyond visual areas, and the interactions between stimuli in linguistic processing areas. In the present study, participants viewed simultaneously presented line drawings at peripheral locations, while in the MRI scanner. The names of the objects depicted in these pictures were either phonologically related (i.e. shared the same consonant-vowel onset construction), or unrelated. Attention was directed either at the linguistic properties of one of these pictures, or at the fixation point (i.e. away from the pictures). Phonological representations of unattended pictures could be detected in the posterior superior temporal gyrus, the inferior frontal gyrus, and the insula. Under some circumstances, the name of ignored distractor pictures is retrieved by linguistic areas. This implies that selective attention to a specific location does not completely filter out the representations of distractor stimuli at early perceptual stages.

  7. Memory guidance in distractor suppression is governed by the availability of cognitive control.

    Science.gov (United States)

    Wen, Wen; Hou, Yin; Li, Sheng

    2018-03-26

    Information stored in the memory systems can affect visual search. Previous studies have shown that holding the to-be-ignored features of distractors in working memory (WM) could accelerate target selection. However, such facilitation effect was only observed when the cued to-be-ignored features remained unchanged within an experimental block (i.e., the fixed cue condition). No search benefit was obtained if the to-be-ignored features varied from trial to trial (i.e., the varied cue condition). In the present study, we conducted three behavioral experiments to investigate whether the WM and long-term memory (LTM) representations of the to-be-ignored features could facilitate visual search in the fixed cue (Experiment 1) and varied cue (Experiments 2 and 3) conditions. Given the importance of the processing time of cognitive control in distractor suppression, we divided visual search trials into five quintiles based on their reaction times (RTs) and examined the temporal characteristics of the suppression effect. Results showed that both the WM and LTM representations of the to-be-ignored features could facilitate distractor suppression in the fixed cue condition, and the facilitation effects were evident across the quintiles in the RT distribution. However, in the varied cue condition, the RT benefits of the WM-matched distractors occurred only in the trials with the longest RTs, whereas no advantage of the LTM-matched distractors was observed. These results suggest that the effective WM-guided distractor suppression depends on the availability of cognitive control and the LTM-guided suppression occurs only if sufficient WM resource is accessible by LTM reactivation.

  8. Same-gender distractors are not so easy to reject: ERP evidence of gender categorization.

    Science.gov (United States)

    Rakić, Tamara; Steffens, Melanie C; Wiese, Holger

    2018-05-07

    Social categorization appears to be an automatic process that occurs during person perception. Understanding social categorization better is important because mere categorization can lead to stereotype activation and, in turn, to discrimination. In the present study we used a novel approach to examine event-related potentials (ERPs) of gender categorization in the "Who said what?" memory paradigm, thus allowing for a more in-depth understanding of the specific mechanisms underlying identity versus categorization processing. After observing video clips showing a "discussion" among female and male targets, participants were shown individual statements, each accompanied by one of the discussants' faces. While we measured ERPs, participants had to decide whether or not a given statement had previously been made by the person with the accompanying face. In same-person trials, statements were paired with the correct person, whereas in the distractor trials, either a same-gender or a different-gender distractor was shown. As expected, participants were able to reject different-gender distractors faster than same-gender distractors, and they were more likely to falsely choose yes for a same-gender than for a different-gender distractor. Both findings indicate gender-based categorization. ERPs, analyzed in a 300- to 400-ms time window at occipito-temporal channels, indicated more negative amplitudes for yes responses both for the same person and for same-gender distractors, relative to different-gender distractors. Overall, these results show gender-based categorization even when the task was to assess the identifying information in a gender-neutral context. These findings are interpreted as showing that gender categorization occurs automatically during person perception, but later than race- or age-based categorization.

  9. Assessing distractors and teamwork during surgery: developing an event-based method for direct observation.

    Science.gov (United States)

    Seelandt, Julia C; Tschan, Franziska; Keller, Sandra; Beldi, Guido; Jenni, Nadja; Kurmann, Anita; Candinas, Daniel; Semmer, Norbert K

    2014-11-01

    To develop a behavioural observation method to simultaneously assess distractors and communication/teamwork during surgical procedures through direct, on-site observations; to establish the reliability of the method for long (>3 h) procedures. Observational categories for an event-based coding system were developed based on expert interviews, observations and a literature review. Using Cohen's κ and the intraclass correlation coefficient, interobserver agreement was assessed for 29 procedures. Agreement was calculated for the entire surgery, and for the 1st hour. In addition, interobserver agreement was assessed between two tired observers and between a tired and a non-tired observer after 3 h of surgery. The observational system has five codes for distractors (door openings, noise distractors, technical distractors, side conversations and interruptions), eight codes for communication/teamwork (case-relevant communication, teaching, leadership, problem solving, case-irrelevant communication, laughter, tension and communication with external visitors) and five contextual codes (incision, last stitch, personnel changes in the sterile team, location changes around the table and incidents). Based on 5-min intervals, Cohen's κ was good to excellent for distractors (0.74-0.98) and for communication/teamwork (0.70-1). Based on frequency counts, intraclass correlation coefficient was excellent for distractors (0.86-0.99) and good to excellent for communication/teamwork (0.45-0.99). After 3 h of surgery, Cohen's κ was 0.78-0.93 for distractors, and 0.79-1 for communication/teamwork. The observational method developed allows a single observer to simultaneously assess distractors and communication/teamwork. Even for long procedures, high interobserver agreement can be achieved. Data collected with this method allow for investigating separate or combined effects of distractions and communication/teamwork on surgical performance and patient outcomes. Published by the

  10. Phonological processing of ignored distractor pictures, an fMRI investigation

    Directory of Open Access Journals (Sweden)

    Bles Mart

    2008-02-01

    Full Text Available Abstract Background Neuroimaging studies of attention often focus on interactions between stimulus representations and top-down selection mechanisms in visual cortex. Less is known about the neural representation of distractor stimuli beyond visual areas, and the interactions between stimuli in linguistic processing areas. In the present study, participants viewed simultaneously presented line drawings at peripheral locations, while in the MRI scanner. The names of the objects depicted in these pictures were either phonologically related (i.e. shared the same consonant-vowel onset construction, or unrelated. Attention was directed either at the linguistic properties of one of these pictures, or at the fixation point (i.e. away from the pictures. Results Phonological representations of unattended pictures could be detected in the posterior superior temporal gyrus, the inferior frontal gyrus, and the insula. Conclusion Under some circumstances, the name of ignored distractor pictures is retrieved by linguistic areas. This implies that selective attention to a specific location does not completely filter out the representations of distractor stimuli at early perceptual stages.

  11. Stronger interference from distractors in the right hemifield during visual search.

    Science.gov (United States)

    Carlei, Christophe; Kerzel, Dirk

    2018-03-01

    The orientation-bias hypothesis states that there is a bias to attend to the right visual hemifield (RVF) when there is spatial competition between stimuli in the left and right hemifield [Pollmann, S. (1996). A pop-out induced extinction-like phenomenon in neurologically intact subjects. Neuropsychologia, 34(5), 413-425. doi: 10.1016/0028-3932(95)00125-5 ]. In support of this hypothesis, stronger interference was reported for RVF distractors with contralateral targets. In contrast, previous studies using rapid serial visual presentation (RSVP) found stronger interference from distractors in the left visual hemifield (LVF). We used the additional singleton paradigm to test whether this discrepancy was due to the different distractor features that were employed (colour vs. orientation). Interference from the colour distractor with contralateral targets was larger in the RVF than in the LVF. However, the asymmetrical interference disappeared when observers had to search for an inconspicuous colour target instead of the inconspicuous shape target. We suggest that the LVF orienting-bias is limited to situations where search is driven by bottom-up saliency (singleton search) instead of top-down search goals (feature search). In contrast, analysis of the literature suggests the opposite for the LVF bias in RSVP tasks. Thus, the attentional asymmetry may depend on whether the task involves temporal or spatial competition, and whether search is based on bottom-up or top-down signals.

  12. Saccadic inhibition can cause the remote distractor effect, but the remote distractor effect may not be a useful concept.

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    McIntosh, Robert D; Buonocore, Antimo

    2014-05-30

    We have suggested that the remote distractor effect (RDE), the elevation of average saccadic reaction time (SRT) induced by a task-irrelevant distractor, may be explained as a statistical consequence of a characteristic reshaping of the SRT distribution known as saccadic inhibition (SI; Buonocore & McIntosh, 2008). In a recent paper, Walker and Benson (2013) argue against this idea and claim that the RDE and SI are partly dissociable. Here, we examine this claim, taking the opportunity to clarify potential ambiguities about how SI affects average SRT, and how the presence of SI can be inferred from SRT distributions.We highlight what we consider to be the most interesting aspects of Walker and Benson’s data, and suggest that a more flexible and nuanced view of SI can account for them. In considering the relation between SI and the RDE, we conclude that the RDE may no longer be a useful concept for eye movement researchers. © 2014 ARVO.

  13. Neural evidence that inhibition is linked to the affective devaluation of distractors that match the contents of working memory.

    Science.gov (United States)

    De Vito, David; Al-Aidroos, Naseem; Fenske, Mark J

    2017-05-01

    Stimuli appearing as visual distractors subsequently receive more negative affective evaluations than novel items or prior targets of attention. Leading accounts question whether this distractor devaluation effect occurs through evaluative codes that become associated with distractors as a mere artefact of attention-task instructions, or through affective consequences of attentional inhibition when applied to prevent distractor interference. Here we test opposing predictions arising from the evaluative-coding and devaluation-by-inhibition hypotheses using an electrophysiological marker of attentional inhibition in a task that requires participants to avoid interference from abstract-shape distractors presented while maintaining a uniquely-colored stimulus in memory. Consistent with prior research, distractors that matched the colour of the stimulus being held in memory elicited a Pd component of the event-related potential waveform, indicating that their processing was being actively suppressed. Subsequent affective evaluations revealed that memory-matching distractors also received more negative ratings than non-matching distractors or previously-unseen shapes. Moreover, Pd magnitude was greater on trials in which the memory-matching distractors were later rated negatively than on trials preceding positive ratings. These results support the devaluation-by-inhibition hypothesis and strongly suggest that fluctuations in stimulus inhibition are closely associated with subsequent affective evaluations. In contrast, none of the evaluative-coding based predictions were confirmed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Augmenting distractor filtering via transcranial magnetic stimulation of the lateral occipital cortex.

    Science.gov (United States)

    Eštočinová, Jana; Lo Gerfo, Emanuele; Della Libera, Chiara; Chelazzi, Leonardo; Santandrea, Elisa

    2016-11-01

    Visual selective attention (VSA) optimizes perception and behavioral control by enabling efficient selection of relevant information and filtering of distractors. While focusing resources on task-relevant information helps counteract distraction, dedicated filtering mechanisms have recently been demonstrated, allowing neural systems to implement suitable policies for the suppression of potential interference. Limited evidence is presently available concerning the neural underpinnings of these mechanisms, and whether neural circuitry within the visual cortex might play a causal role in their instantiation, a possibility that we directly tested here. In two related experiments, transcranial magnetic stimulation (TMS) was applied over the lateral occipital cortex of healthy humans at different times during the execution of a behavioral task which entailed varying levels of distractor interference and need for attentional engagement. While earlier TMS boosted target selection, stimulation within a restricted time epoch close to (and in the course of) stimulus presentation engendered selective enhancement of distractor suppression, by affecting the ongoing, reactive instantiation of attentional filtering mechanisms required by specific task conditions. The results attest to a causal role of mid-tier ventral visual areas in distractor filtering and offer insights into the mechanisms through which TMS may have affected ongoing neural activity in the stimulated tissue. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Distractor Interference during Smooth Pursuit Eye Movements

    Science.gov (United States)

    Spering, Miriam; Gegenfurtner, Karl R.; Kerzel, Dirk

    2006-01-01

    When 2 targets for pursuit eye movements move in different directions, the eye velocity follows the vector average (S. G. Lisberger & V. P. Ferrera, 1997). The present study investigates the mechanisms of target selection when observers are instructed to follow a predefined horizontal target and to ignore a moving distractor stimulus. Results show…

  16. What determines auditory distraction? On the roles of local auditory changes and expectation violations.

    Directory of Open Access Journals (Sweden)

    Jan P Röer

    Full Text Available Both the acoustic variability of a distractor sequence and the degree to which it violates expectations are important determinants of auditory distraction. In four experiments we examined the relative contribution of local auditory changes on the one hand and expectation violations on the other hand in the disruption of serial recall by irrelevant sound. We present evidence for a greater disruption by auditory sequences ending in unexpected steady state distractor repetitions compared to auditory sequences with expected changing state endings even though the former contained fewer local changes. This effect was demonstrated with piano melodies (Experiment 1 and speech distractors (Experiment 2. Furthermore, it was replicated when the expectation violation occurred after the encoding of the target items (Experiment 3, indicating that the items' maintenance in short-term memory was disrupted by attentional capture and not their encoding. This seems to be primarily due to the violation of a model of the specific auditory distractor sequences because the effect vanishes and even reverses when the experiment provides no opportunity to build up a specific neural model about the distractor sequence (Experiment 4. Nevertheless, the violation of abstract long-term knowledge about auditory regularities seems to cause a small and transient capture effect: Disruption decreased markedly over the course of the experiments indicating that participants habituated to the unexpected distractor repetitions across trials. The overall pattern of results adds to the growing literature that the degree to which auditory distractors violate situation-specific expectations is a more important determinant of auditory distraction than the degree to which a distractor sequence contains local auditory changes.

  17. Validity and Reliability of Scores Obtained on Multiple-Choice Questions: Why Functioning Distractors Matter

    Science.gov (United States)

    Ali, Syed Haris; Carr, Patrick A.; Ruit, Kenneth G.

    2016-01-01

    Plausible distractors are important for accurate measurement of knowledge via multiple-choice questions (MCQs). This study demonstrates the impact of higher distractor functioning on validity and reliability of scores obtained on MCQs. Freeresponse (FR) and MCQ versions of a neurohistology practice exam were given to four cohorts of Year 1 medical…

  18. Reward association facilitates distractor suppression in human visual search.

    Science.gov (United States)

    Gong, Mengyuan; Yang, Feitong; Li, Sheng

    2016-04-01

    Although valuable objects are attractive in nature, people often encounter situations where they would prefer to avoid such distraction while focusing on the task goal. Contrary to the typical effect of attentional capture by a reward-associated item, we provide evidence for a facilitation effect derived from the active suppression of a high reward-associated stimulus when cuing its identity as distractor before the display of search arrays. Selection of the target is shown to be significantly faster when the distractors were in high reward-associated colour than those in low reward-associated or non-rewarded colours. This behavioural reward effect was associated with two neural signatures before the onset of the search display: the increased frontal theta oscillation and the strengthened top-down modulation from frontal to anterior temporal regions. The former suggests an enhanced working memory representation for the reward-associated stimulus and the increased need for cognitive control to override Pavlovian bias, whereas the latter indicates that the boost of inhibitory control is realized through a frontal top-down mechanism. These results suggest a mechanism in which the enhanced working memory representation of a reward-associated feature is integrated with task demands to modify attentional priority during active distractor suppression and benefit behavioural performance. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  19. Effects of cognitive load on neural and behavioral responses to smoking cue distractors

    Science.gov (United States)

    MacLean, R. Ross; Nichols, Travis T.; LeBreton, James M.; Wilson, Stephen J.

    2017-01-01

    Smoking cessation failures are frequently thought to reflect poor top-down regulatory control over behavior. Previous studies suggest that smoking cues occupy limited working memory resources, an effect that may contribute to difficulty achieving abstinence. Few studies have evaluated the effects of cognitive load on the ability to actively maintain information in the face of distracting smoking cues. The current study adapted an fMRI probed recall task under low and high cognitive load with three distractor conditions: control, neutral images, or smoking-related images. Consistent with a limited-resource model of cue reactivity, we predicted that performance of daily smokers (n=17) would be most impaired when high load was paired with smoking distractors. Results demonstrated a main effect of load, with decreased accuracy under high, compared to low, cognitive load. Surprisingly, an interaction revealed the effect of load was weakest in the smoking cue distractor condition. Along with this behavioral effect, we observed significantly greater activation of the right inferior frontal gyrus (rIFG) in the low load condition relative to the high load condition for trials containing smoking cue distractors. Furthermore, load-related changes in rIFG activation partially mediated the effects of load on task accuracy in the smoking cue distractor condition. These findings are discussed in the context of prevailing cognitive and cue reactivity theories. Results suggest that high cognitive load does not necessarily make smokers more susceptible to interference from smoking-related stimuli, and that elevated load may even have a buffering effect in the presence of smoking cues under certain conditions. PMID:27012714

  20. Segmental Maxillary Distraction Osteogenesis With a Hybrid-Type Distractor in the Management of Wide Alveolar Cleft.

    Science.gov (United States)

    Zhang, Jianfei; Zhang, Wenbin; Shen, Steve Guofang

    2018-01-01

    To investigate segmental maxillary distraction osteogenesis (DO) with hybrid-type distractor in the management of wide alveolar cleft. Six patients underwent segmental DO with a hybrid-type distractor. After the success of DO and 3-month consolidation period, removal of the distractor was accompanied by alveolar bone graft with iliac bone. Panoramic radiograph and computed tomography scanning were taken preoperatively (T0) and the day after distractor removal (T1). The crest distance between the long axis of cleft nearby teeth was measured. All patients completed the DO period, and the succeeding alveolar bone graft healing was uneventful. The mean cleft distance decrease was 12.05 mm (range: 10.1-13.5 mm). As for the mobility degree record of abutment tooth in the transport segment recorded, 6 patients were grading I° at T0, while 5 patients were grading I° and 1 patient was grading II° at T1. Segmental maxillary DO with the hybrid-type distractor is successful to reduce the cleft width in these cases, and it is promising in the treatment of wide dental alveolar cleft, especially for the adult patient.

  1. Effects of cognitive load on neural and behavioral responses to smoking-cue distractors.

    Science.gov (United States)

    MacLean, R Ross; Nichols, Travis T; LeBreton, James M; Wilson, Stephen J

    2016-08-01

    Smoking cessation failures are frequently thought to reflect poor top-down regulatory control over behavior. Previous studies have suggested that smoking cues occupy limited working memory resources, an effect that may contribute to difficulty achieving abstinence. Few studies have evaluated the effects of cognitive load on the ability to actively maintain information in the face of distracting smoking cues. For the present study, we adapted an fMRI probed recall task under low and high cognitive load with three distractor conditions: control, neutral images, or smoking-related images. Consistent with a limited-resource model of cue reactivity, we predicted that the performance of daily smokers (n = 17) would be most impaired when high load was paired with smoking distractors. The results demonstrated a main effect of load, with decreased accuracy under high, as compared to low, cognitive load. Surprisingly, an interaction revealed that the effect of load was weakest in the smoking cue distractor condition. Along with this behavioral effect, we observed significantly greater activation of the right inferior frontal gyrus (rIFG) in the low-load condition than in the high-load condition for trials containing smoking cue distractors. Furthermore, load-related changes in rIFG activation partially mediated the effects of load on task accuracy in the smoking-cue distractor condition. These findings are discussed in the context of prevailing cognitive and cue reactivity theories. These results suggest that high cognitive load does not necessarily make smokers more susceptible to interference from smoking-related stimuli, and that elevated load may even have a buffering effect in the presence of smoking cues under certain conditions.

  2. Effects of working memory contents and perceptual load on distractor processing: When a response-related distractor is held in working memory.

    Science.gov (United States)

    Koshino, Hideya

    2017-01-01

    Working memory and attention are closely related. Recent research has shown that working memory can be viewed as internally directed attention. Working memory can affect attention in at least two ways. One is the effect of working memory load on attention, and the other is the effect of working memory contents on attention. In the present study, an interaction between working memory contents and perceptual load in distractor processing was investigated. Participants performed a perceptual load task in a standard form in one condition (Single task). In the other condition, a response-related distractor was maintained in working memory, rather than presented in the same stimulus display as a target (Dual task). For the Dual task condition, a significant compatibility effect was found under high perceptual load; however, there was no compatibility effect under low perceptual load. These results suggest that the way the contents of working memory affect visual search depends on perceptual load. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Auditory Attentional Capture: Effects of Singleton Distractor Sounds

    Science.gov (United States)

    Dalton, Polly; Lavie, Nilli

    2004-01-01

    The phenomenon of attentional capture by a unique yet irrelevant singleton distractor has typically been studied in visual search. In this article, the authors examine whether a similar phenomenon occurs in the auditory domain. Participants searched sequences of sounds for targets defined by frequency, intensity, or duration. The presence of a…

  4. Investigating the flow of information during speaking: The impact of morpho-phonological, associative and categorical picture distractors on picture naming

    Directory of Open Access Journals (Sweden)

    Jens eBölte

    2015-10-01

    Full Text Available In three experiments, participants named target pictures by means of German compound words (e.g., Gartenstuhl - garden chair, each accompanied by two different distractor pictures (e.g., lawn mower and swimming pool.Targets and distractor pictures were semantically related, either associatively (garden chair and lawn mower or by a shared semantic category (garden chair and wardrobe. Within each type of semantic relation, target and distractor pictures either shared morpho-phonological (word-form information (Gartenstuhl with Gartenzwerg, garden gnome, and Gartenschlauch, garden hose or not. A condition with two completely unrelated pictures served as baseline. Target naming was facilitated when distractor and target pictures were morpho-phonologically related. This is clear evidence for the activation of lexical information of distractor pictures. Effects were larger for associatively than for categorically related distractors and targets, which constitutes evidence for lexical competition. Mere categorical relatedness, in the absence of morpho-phonological overlap, resulted in null effects (Experiments 1 and 2, and only speeded target naming when effects reflect only conceptual, not lexical processing (Experiment 3. Given that distractor pictures activate their word forms, the data cannot be easily reconciled with discrete serial models. The results fit well with models that allow information to cascade forward from conceptual to word-form levels.

  5. Investigating the flow of information during speaking: the impact of morpho-phonological, associative, and categorical picture distractors on picture naming.

    Science.gov (United States)

    Bölte, Jens; Böhl, Andrea; Dobel, Christian; Zwitserlood, Pienie

    2015-01-01

    In three experiments, participants named target pictures by means of German compound words (e.g., Gartenstuhl-garden chair), each accompanied by two different distractor pictures (e.g., lawn mower and swimming pool). Targets and distractor pictures were semantically related either associatively (garden chair and lawn mower) or by a shared semantic category (garden chair and wardrobe). Within each type of semantic relation, target and distractor pictures either shared morpho-phonological (word-form) information (Gartenstuhl with Gartenzwerg, garden gnome, and Gartenschlauch, garden hose) or not. A condition with two completely unrelated pictures served as baseline. Target naming was facilitated when distractor and target pictures were morpho-phonologically related. This is clear evidence for the activation of word-form information of distractor pictures. Effects were larger for associatively than for categorically related distractors and targets, which constitute evidence for lexical competition. Mere categorical relatedness, in the absence of morpho-phonological overlap, resulted in null effects (Experiments 1 and 2), and only speeded target naming when effects reflect only conceptual, but not lexical processing (Experiment 3). Given that distractor pictures activate their word forms, the data cannot be easily reconciled with discrete serial models. The results fit well with models that allow information to cascade forward from conceptual to word-form levels.

  6. The occipital place area represents the local elements of scenes.

    Science.gov (United States)

    Kamps, Frederik S; Julian, Joshua B; Kubilius, Jonas; Kanwisher, Nancy; Dilks, Daniel D

    2016-05-15

    Neuroimaging studies have identified three scene-selective regions in human cortex: parahippocampal place area (PPA), retrosplenial complex (RSC), and occipital place area (OPA). However, precisely what scene information each region represents is not clear, especially for the least studied, more posterior OPA. Here we hypothesized that OPA represents local elements of scenes within two independent, yet complementary scene descriptors: spatial boundary (i.e., the layout of external surfaces) and scene content (e.g., internal objects). If OPA processes the local elements of spatial boundary information, then it should respond to these local elements (e.g., walls) themselves, regardless of their spatial arrangement. Indeed, we found that OPA, but not PPA or RSC, responded similarly to images of intact rooms and these same rooms in which the surfaces were fractured and rearranged, disrupting the spatial boundary. Next, if OPA represents the local elements of scene content information, then it should respond more when more such local elements (e.g., furniture) are present. Indeed, we found that OPA, but not PPA or RSC, responded more to multiple than single pieces of furniture. Taken together, these findings reveal that OPA analyzes local scene elements - both in spatial boundary and scene content representation - while PPA and RSC represent global scene properties. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Influence of COMT genotype and affective distractors on the processing of self-generated thought.

    Science.gov (United States)

    Kilford, Emma J; Dumontheil, Iroise; Wood, Nicholas W; Blakemore, Sarah-Jayne

    2015-06-01

    The catechol-O-methyltransferase (COMT) enzyme is a major determinant of prefrontal dopamine levels. The Val(158)Met polymorphism affects COMT enzymatic activity and has been associated with variation in executive function and affective processing. This study investigated the effect of COMT genotype on the flexible modulation of the balance between processing self-generated and processing stimulus-oriented information, in the presence or absence of affective distractors. Analyses included 124 healthy adult participants, who were also assessed on standard working memory (WM) tasks. Relative to Val carriers, Met homozygotes made fewer errors when selecting and manipulating self-generated thoughts. This effect was partly accounted for by an association between COMT genotype and visuospatial WM performance. We also observed a complex interaction between the influence of affective distractors, COMT genotype and sex on task accuracy: male, but not female, participants showed a sensitivity to the affective distractors that was dependent on COMT genotype. This was not accounted for by WM performance. This study provides novel evidence of the role of dopaminergic genetic variation on the ability to select and manipulate self-generated thoughts. The results also suggest sexually dimorphic effects of COMT genotype on the influence of affective distractors on executive function. © The Author (2014). Published by Oxford University Press.

  8. Subthalamic nucleus deep brain stimulation affects distractor interference in auditory working memory.

    Science.gov (United States)

    Camalier, Corrie R; Wang, Alice Y; McIntosh, Lindsey G; Park, Sohee; Neimat, Joseph S

    2017-03-01

    Computational and theoretical accounts hypothesize the basal ganglia play a supramodal "gating" role in the maintenance of working memory representations, especially in preservation from distractor interference. There are currently two major limitations to this account. The first is that supporting experiments have focused exclusively on the visuospatial domain, leaving questions as to whether such "gating" is domain-specific. The second is that current evidence relies on correlational measures, as it is extremely difficult to causally and reversibly manipulate subcortical structures in humans. To address these shortcomings, we examined non-spatial, auditory working memory performance during reversible modulation of the basal ganglia, an approach afforded by deep brain stimulation of the subthalamic nucleus. We found that subthalamic nucleus stimulation impaired auditory working memory performance, specifically in the group tested in the presence of distractors, even though the distractors were predictable and completely irrelevant to the encoding of the task stimuli. This study provides key causal evidence that the basal ganglia act as a supramodal filter in working memory processes, further adding to our growing understanding of their role in cognition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Local anaphor licensing in an SOV language: implications for retrieval strategies

    Science.gov (United States)

    Kush, Dave; Phillips, Colin

    2014-01-01

    Because morphological and syntactic constraints govern the distribution of potential antecedents for local anaphors, local antecedent retrieval might be expected to make equal use of both syntactic and morphological cues. However, previous research (e.g., Dillon et al., 2013) has shown that local antecedent retrieval is not susceptible to the same morphological interference effects observed during the resolution of morphologically-driven grammatical dependencies, such as subject-verb agreement checking (e.g., Pearlmutter et al., 1999). Although this lack of interference has been taken as evidence that syntactic cues are given priority over morphological cues in local antecedent retrieval, the absence of interference could also be the result of a confound in the materials used: the post-verbal position of local anaphors in prior studies may obscure morphological interference that would otherwise be visible if the critical anaphor were in a different position. We investigated the licensing of local anaphors (reciprocals) in Hindi, an SOV language, in order to determine whether pre-verbal anaphors are subject to morphological interference from feature-matching distractors in a way that post-verbal anaphors are not. Computational simulations using a version of the ACT-R parser (Lewis and Vasishth, 2005) predicted that a feature-matching distractor should facilitate the processing of an unlicensed reciprocal if morphological cues are used in antecedent retrieval. In a self-paced reading study we found no evidence that distractors eased processing of an unlicensed reciprocal. However, the presence of a distractor increased difficulty of processing following the reciprocal. We discuss the significance of these results for theories of cue selection in retrieval. PMID:25414680

  10. Local Anaphor Licensing in an SOV Language: Implications for Retrieval Strategies

    Directory of Open Access Journals (Sweden)

    Dave eKush

    2014-11-01

    Full Text Available Because morphological and syntactic constraints govern the distribution of potential antecedents for local anaphors, local antecedent retrieval might be expected to make equal use of both syntactic and morphological cues. However, previous research (e.g., Dillon et al., 2013 has shown that local antecedent retrieval is not susceptible to the same morphological interference effects observed during the resolution of morphologically-driven grammatical dependencies, such as subject-verb agreement checking (e.g., Pearlmutter, Garnsey and Bock, 1999. Although this lack of interference has been taken as evidence that syntactic cues are given priority over morphological cues in local antecedent retrieval, the absence of interference could also be the result of a confound in the materials used: the post-verbal position of local anaphors in prior studies may obscure morphological interference that would otherwise be visible if the critical anaphor were in a different position. We investigated the licensing of local anaphors (reciprocals in Hindi, an SOV language, in order to determine whether pre-verbal anaphors are subject to morphological interference from feature-matching distractors in a way that post-verbal anaphors are not. Computational simulations using a version of the ACT-R parser (Lewis and Vasishth, 2005 predicted that a feature-matching distractor should facilitate the processing of an unlicensed reciprocal if morphological cues are used in antecedent retrieval. In a self-paced reading study we found no evidence that distractors eased processing of an unlicensed reciprocal. However, the presence of a distractor increased difficulty of processing following the reciprocal. We discuss the significance of these results for theories of cue selection in retrieval.

  11. Maxillary anterior segmental distraction osteogenesis with 2 different types of distractors.

    Science.gov (United States)

    Choi, Hye-Young; Hwang, Chung-Ju; Kim, Hee-Jin; Yu, Hyung-Seog; Cha, Jung-Yul

    2012-05-01

    Maxillary anterior segmental distraction osteogenesis (DO) has been the alternative treatment option for patients with midfacial retrusion. To investigate a potentially more effective maxillary anterior segmental DO, a newly designed intraoral alveolar distractor was applied. The objectives of this study were to investigate the skeletal and dental effects of maxillary anterior segmental DO and the relapse pattern. The study was carried out for 8 patients with unilateral cleft lip and palate (mean age, 16 years 7 months). Four patients were treated with an intraoral appliance (IA), and the remaining with a rigid external distractor (RED). Dental and skeletal measurements were obtained for both groups. These measurements were compared for different time points including pre-DO (T1), post-DO (T2), postconsolidation (T3), and 1-year follow-up (T4). Horizontal change of A point was significantly larger after distraction period (T2) in the RED group (mean, 11.0 mm; median, 10.1 mm) than in the IA group (mean, 6.6 mm; median, 7.4 mm) (P distraction, showing a significant difference between groups (P Maxillary anterior segmental DO is effective for the treatment of patients with cleft lip and palate. The alveolar space is regained, and the facial profile is improved without velopharyngeal problems. Superior results are obtained using the RED appliance for maxillary anterior segmental DO relative to the use of the intraoral distractor appliance.

  12. Combined Electrophysiological and Behavioral Evidence for the Suppression of Salient Distractors.

    Science.gov (United States)

    Gaspelin, Nicholas; Luck, Steven J

    2018-05-15

    Researchers have long debated how salient-but-irrelevant features guide visual attention. Pure stimulus-driven theories claim that salient stimuli automatically capture attention irrespective of goals, whereas pure goal-driven theories propose that an individual's attentional control settings determine whether salient stimuli capture attention. However, recent studies have suggested a hybrid model in which salient stimuli attract visual attention but can be actively suppressed by top-down attentional mechanisms. Support for this hybrid model has primarily come from ERP studies demonstrating that salient stimuli, which fail to capture attention, also elicit a distractor positivity (P D ) component, a putative neural index of suppression. Other support comes from a handful of behavioral studies showing that processing at the salient locations is inhibited compared with other locations. The current study was designed to link the behavioral and neural evidence by combining ERP recordings with an experimental paradigm that provides a behavioral measure of suppression. We found that, when a salient distractor item elicited the P D component, processing at the location of this distractor was suppressed below baseline levels. Furthermore, the magnitude of behavioral suppression and the magnitude of the P D component covaried across participants. These findings provide a crucial connection between the behavioral and neural measures of suppression, which opens the door to using the P D component to assess the timing and neural substrates of the behaviorally observed suppression.

  13. Open and closed cortico-subcortical loops: A neuro-computational account of access to consciousness in the distractor-induced blindness paradigm.

    Science.gov (United States)

    Ebner, Christian; Schroll, Henning; Winther, Gesche; Niedeggen, Michael; Hamker, Fred H

    2015-09-01

    How the brain decides which information to process 'consciously' has been debated over for decades without a simple explanation at hand. While most experiments manipulate the perceptual energy of presented stimuli, the distractor-induced blindness task is a prototypical paradigm to investigate gating of information into consciousness without or with only minor visual manipulation. In this paradigm, subjects are asked to report intervals of coherent dot motion in a rapid serial visual presentation (RSVP) stream, whenever these are preceded by a particular color stimulus in a different RSVP stream. If distractors (i.e., intervals of coherent dot motion prior to the color stimulus) are shown, subjects' abilities to perceive and report intervals of target dot motion decrease, particularly with short delays between intervals of target color and target motion. We propose a biologically plausible neuro-computational model of how the brain controls access to consciousness to explain how distractor-induced blindness originates from information processing in the cortex and basal ganglia. The model suggests that conscious perception requires reverberation of activity in cortico-subcortical loops and that basal-ganglia pathways can either allow or inhibit this reverberation. In the distractor-induced blindness paradigm, inadequate distractor-induced response tendencies are suppressed by the inhibitory 'hyperdirect' pathway of the basal ganglia. If a target follows such a distractor closely, temporal aftereffects of distractor suppression prevent target identification. The model reproduces experimental data on how delays between target color and target motion affect the probability of target detection. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Conventional bone-anchored palatal distractor using an orthodontic palatal expander for the transverse maxillary distraction osteogenesis: technical note.

    Science.gov (United States)

    Iida, Seiji; Haraguchi, Seiji; Aikawa, Tomonao; Yashiro, Kohtaro; Okura, Masaya; Kogo, Mikihiko

    2008-02-01

    Surgical-assisted rapid palatal expansion includes various treatment procedures for solving transverse maxillary deficiencies, especially in cases with a matured palatal suture. Recent introduction of the concept of distraction osteogenesis has contributed to generalize this useful treatment and to develop some bone-borne devices that will not cause the problems found in cases treated by tooth-supported palatal expander. This report shows a conventional bone-borne distractor using commercially available orthodontic palatal expansion screws. The distractor consists of 2 parts: one is a commercially available orthodontic palatal expansion screw (Hyrax type, Fan style) and another is a screw-ring, which is one of the attached parts of the mandibular distraction system. The bone screws are inserted transmucosally to the palatal bone via the screw-rings. The palatal distractor can be applied to varied palatal shapes and can expand the palate without any trouble. This conventional palatal distractor may contribute to generalize the transpalatal maxillary distraction osteogenesis for cases with maxillary teeth problems.

  15. Functional imaging correlates of impaired distractor suppression following sleep deprivation.

    Science.gov (United States)

    Kong, Danyang; Soon, Chun Siong; Chee, Michael W L

    2012-05-15

    Sleep deprivation (SD) has been shown to affect selective attention but it is not known how two of its component processes: target enhancement and distractor suppression, are affected. To investigate, young volunteers either attended to houses or were obliged to ignore them (when attending to faces) while viewing superimposed face-house pictures. MR signal enhancement and suppression in the parahippocampal place area (PPA) were determined relative to a passive viewing control condition. Sleep deprivation was associated with lower PPA activation across conditions. Critically SD specifically impaired distractor suppression in selective attention, leaving target enhancement relatively preserved. These findings parallel some observations in cognitive aging. Additionally, following SD, attended houses were not significantly better recognized than ignored houses in a post-experiment test of recognition memory contrasting with the finding of superior recognition of attended houses in the well-rested state. These results provide evidence for co-encoding of distracting information with targets into memory when one is sleep deprived. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. [An adjustable distractor for transverse maxillary distraction osteogenesis].

    Science.gov (United States)

    Leyder, P; Wycisk, G; Quilichini, J

    2013-06-01

    The posterior skeletal widening in conventional distractions (Surgical Assisted Rapid Maxillary Expansion) is often modest, in contrast with a predominant anterior expansion. Until recently, it was not possible to consider transverse palatal distraction osteogenesis and Le Fort I impaction or advancement in the same procedure, as the osteosynthesis plates impeded maxillary anterior opening. We developed new sliding osteosynthesis plates allowing to perform an advancement or impaction Le Fort I osteotomy associated with a low-resistance bipartite palatal distraction osteogenesis. We had for aim to describe the device and to determine its clinical applications. This new palatal distractor is made up of two independent stainless steel jacks allowing for an adjustable distraction in the anterior or posterior area as needed. Bone-borne and tooth-borne versions are available. This new distractor can be adjusted sagittally. The distraction can be angular or parallel, and the distraction mode can be modified during post-operative distraction. This device should be adapted to all clinical presentations. It can be used in combination with sliding osteosynthesis to perform a Le Fort 1 osteotomy and at the same time a complete correction of vertical, horizontal, and sagittal deficiencies. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  17. Perceptual load modulates anterior cingulate cortex response to threat distractors in generalized social anxiety disorder.

    Science.gov (United States)

    Wheaton, Michael G; Fitzgerald, Daniel A; Phan, K Luan; Klumpp, Heide

    2014-09-01

    Generalized social anxiety disorder (gSAD) is associated with impoverished anterior cingulate cortex (ACC) engagement during attentional control. Attentional Control Theory proposes such deficiencies may be offset when demands on resources are increased to execute goals. To test the hypothesis attentional demands affect ACC response 23 patients with gSAD and 24 matched controls performed an fMRI task involving a target letter in a string of identical targets (low load) or a target letter in a mixed letter string (high load) superimposed on fearful, angry, and neutral face distractors. Regardless of load condition, groups were similar in accuracy and reaction time. Under low load gSAD patients showed deficient rostral ACC recruitment to fearful (vs. neutral) distractors. For high load, increased activation to fearful (vs. neutral) distractors was observed in gSAD suggesting a compensatory function. Results remained after controlling for group differences in depression level. Findings indicate perceptual demand modulates ACC in gSAD. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Vision affects tactile target and distractor processing even when space is task-irrelevant

    Directory of Open Access Journals (Sweden)

    Ann-Katrin eWesslein

    2014-02-01

    Full Text Available The human brain is adapted to integrate the information from multiple sensory modalities into coherent, robust representations of the objects and events in the external world. A large body of empirical research has demonstrated the ubiquitous nature of the interactions that take place between vision and touch, with the former typically dominating over the latter. Many studies have investigated the influence of visual stimuli on the processing of tactile stimuli (and vice versa. Other studies, meanwhile, have investigated the effect of directing a participant’s gaze either toward or else away from the body-part receiving the target tactile stimulation. Other studies, by contrast, have compared performance in those conditions in which the participant’s eyes have been open versus closed. We start by reviewing the research that has been published to date demonstrating the influence of vision on the processing of tactile targets, that is, on those stimuli that have to be attended or responded to. We outline that many – but not all – of the visuotactile interactions that have been observed to date may be attributable to the direction of spatial attention. We then move on to focus on the crossmodal influence of vision, as well as of the direction of gaze, on the processing of tactile distractors. We highlight the results of those studies demonstrating the influence of vision, rather than gaze direction (i.e., the direction of overt spatial attention, on tactile distractor processing (e.g., tactile variants of the negative-priming or flanker task. The conclusion is that no matter how vision of a tactile distractor is engaged, the result would appear to be the same, namely that tactile distractors are processed more thoroughly.

  19. Adults with dyslexia demonstrate large effects of crowding and detrimental effects of distractors in a visual tilt discrimination task.

    Directory of Open Access Journals (Sweden)

    Rizan Cassim

    Full Text Available Previous research has shown that adults with dyslexia (AwD are disproportionately impacted by close spacing of stimuli and increased numbers of distractors in a visual search task compared to controls [1]. Using an orientation discrimination task, the present study extended these findings to show that even in conditions where target search was not required: (i AwD had detrimental effects of both crowding and increased numbers of distractors; (ii AwD had more pronounced difficulty with distractor exclusion in the left visual field and (iii measures of crowding and distractor exclusion correlated significantly with literacy measures. Furthermore, such difficulties were not accounted for by the presence of covarying symptoms of ADHD in the participant groups. These findings provide further evidence to suggest that the ability to exclude distracting stimuli likely contributes to the reported visual attention difficulties in AwD and to the aetiology of literacy difficulties. The pattern of results is consistent with weaker and asymmetric attention in AwD.

  20. Is It Working? Distractor Analysis Results from the Test Of Astronomy STandards (TOAST) Assessment Instrument

    Science.gov (United States)

    Slater, Stephanie

    2009-05-01

    The Test Of Astronomy STandards (TOAST) assessment instrument is a multiple-choice survey tightly aligned to the consensus learning goals stated by the American Astronomical Society - Chair's Conference on ASTRO 101, the American Association of the Advancement of Science's Project 2061 Benchmarks, and the National Research Council's National Science Education Standards. Researchers from the Cognition in Astronomy, Physics and Earth sciences Research (CAPER) Team at the University of Wyoming's Science and Math Teaching Center (UWYO SMTC) have been conducting a question-by-question distractor analysis procedure to determine the sensitivity and effectiveness of each item. In brief, the frequency each possible answer choice, known as a foil or distractor on a multiple-choice test, is determined and compared to the existing literature on the teaching and learning of astronomy. In addition to having statistical difficulty and discrimination values, a well functioning assessment item will show students selecting distractors in the relative proportions to how we expect them to respond based on known misconceptions and reasoning difficulties. In all cases, our distractor analysis suggests that all items are functioning as expected. These results add weight to the validity of the Test Of Astronomy STandards (TOAST) assessment instrument, which is designed to help instructors and researchers measure the impact of course-length duration instructional strategies for undergraduate science survey courses with learning goals tightly aligned to the consensus goals of the astronomy education community.

  1. The role of modality : Auditory and visual distractors in Stroop interference

    NARCIS (Netherlands)

    Elliott, Emily M.; Morey, Candice C.; Morey, Richard D.; Eaves, Sharon D.; Shelton, Jill Talley; Lutfi-Proctor, Danielle A.

    2014-01-01

    As a commonly used measure of selective attention, it is important to understand the factors contributing to interference in the Stroop task. The current research examined distracting stimuli in the auditory and visual modalities to determine whether the use of auditory distractors would create

  2. A finite element study on the effects of midsymphyseal distraction osteogenesis on the mandible and articular disc.

    Science.gov (United States)

    Kim, Ki-Nam; Cha, Bong-Kuen; Choi, Dong-Soon; Jang, Insan; Yi, Yang-Jin; Jost-Brinkmann, Paul-Georg

    2012-05-01

    To evaluate the biomechanical effect of midsymphyseal distraction osteogenesis with three types of distractors on the mandible and articular disc using a three-dimensional finite element model analysis. A virtual model of the mandible was produced from computed tomography scan images of a healthy 27-year-old man. On the finite element model of the mandible, expansion of the bone-borne, tooth-borne, and hybrid type distractors were simulated with the jaw-closing muscles. The displacement and stress distribution of the mandible and articular disc were analyzed. With the bone-borne appliance the alveolar process area was displaced more than the basal bone area. The tooth-borne appliance displaced the mandibular body in a parallel manner and showed high level of the von Mises stress in the alveolar process and the ramal region as well as in the condylar neck area. The hybrid type showed medium amount of displacement and stress distribution compared with the bone-borne and tooth-borne type. At the articular disc the compressive stress was concentrated in the anteromedial and posterolateral area, and it was highest in the tooth-borne distractor, followed by hybrid appliance and bone-borne appliance. The tooth-borne distractor produced more parallel bony widening in the midsymphyseal area and larger expansion in the molar region; however, it induced higher stress concentration on the articular disc than the hybrid appliance and bone-borne appliance. Whether any long-term side effects on the temporomandibular joint are anticipated, especially in tooth-borne distractor, remains to be investigated.

  3. Ground-based inhibition: Suppressive perceptual mechanisms interact with top-down attention to reduce distractor interference.

    Science.gov (United States)

    Wager, Erica; Peterson, Mary A; Folstein, Jonathan R; Scalf, Paige E

    2015-01-01

    Successful attentional function requires inhibition of distracting information (e.g., Deutsch & Deutsch, 1963). Similarly, perceptual segregation of the visual world into figure and ground entails ground suppression (e.g., Likova & Tyler, 2008; Peterson & Skow, 2008). Here, we ask whether the suppressive processes of attention and perception-distractor inhibition and ground suppression-interact to more effectively insulate task performance from interfering information. We used a variant of the Eriksen flanker paradigm to assess the efficacy of distractor inhibition. Participants indicated the right/left orientation of a central arrow, which could be flanked by congruent, neutral, or incongruent stimuli. We manipulated the degree to which the ground region of a display was suppressed and measured the influence of this manipulation on the efficacy with which participants could inhibit responses from incongruent flankers. Greater ground suppression reduced the influence on target identification of interfering, incongruent information, but not that of facilitative, congruent information. These data are the first to show that distractor inhibition interacts with ground suppression to improve attentional function.

  4. Early, but not late visual distractors affect movement synchronization to a temporal-spatial visual cue

    Directory of Open Access Journals (Sweden)

    Ashley J Booth

    2015-06-01

    Full Text Available The ease of synchronising movements to a rhythmic cue is dependent on the modality of the cue presentation: timing accuracy is much higher when synchronising with discrete auditory rhythms than an equivalent visual stimulus presented through flashes. However, timing accuracy is improved if the visual cue presents spatial as well as temporal information (e.g. a dot following an oscillatory trajectory. Similarly, when synchronising with an auditory target metronome in the presence of a second visual distracting metronome, the distraction is stronger when the visual cue contains spatial-temporal information rather than temporal only. The present study investigates individuals’ ability to synchronise movements to a temporal-spatial visual cue in the presence of same-modality temporal-spatial distractors. Moreover, we investigated how increasing the number of distractor stimuli impacted on maintaining synchrony with the target cue. Participants made oscillatory vertical arm movements in time with a vertically oscillating white target dot centred on a large projection screen. The target dot was surrounded by 2, 8 or 14 distractor dots, which had an identical trajectory to the target but at a phase lead or lag of 0, 100 or 200ms. We found participants’ timing performance was only affected in the phase-lead conditions and when there were large numbers of distractors present (8 and 14. This asymmetry suggests participants still rely on salient events in the stimulus trajectory to synchronise movements. Subsequently, distractions occurring in the window of attention surrounding those events have the maximum impact on timing performance.

  5. The Effect of Using a Modified Dentoalveolar Distractor on Canine Angulation following Rapid Canine Retraction: A Split-mouth Design Randomized Controlled Trial.

    Science.gov (United States)

    Al-Ainawi, Khaled I; Al-Mdalal, Yaser; Hajeer, Mohammad Y

    2016-01-01

    New studies have been published and aimed to retract canines by means of distraction osteogenesis to reduce treatment time. Although a great care has been given to achieve a bodily movement of the canines, a significant amount of tipping of the canines has been observed. This trial aimed to assess the effect of applying a modified distractor on canine angulation. The sample of the study consisted of 14 canines in seven patients (16-25 years). After the osteotomy procedure, two distractors were applied (one distractor on each side). After 5 days of a latency period, the two distractors were activated at a rate of 1 mm/day. There was a significant difference between the two distractors regarding the time required to retract the canines (p = 0.008) and the observed change in canine angulation following retraction (p = 0.028). The change in the overjet and the mandibular plane angle was statistically insignificant. Eight out of 14 distracted canines reacted positively to the pulp vitality tester after 3 months of completion of distraction. There was no clinical sign of discoloration or pulpal pain in any canine. Within the limits of this study, the modified distractor caused a bodily movement of the canine with a minimal tipping. Further research is required on a long-term basis on a larger group of patients to gain more insight on the observed changes.

  6. Task demands affect spatial reference frame weighting during tactile localization in sighted and congenitally blind adults.

    Directory of Open Access Journals (Sweden)

    Jonathan T W Schubert

    Full Text Available Task demands modulate tactile localization in sighted humans, presumably through weight adjustments in the spatial integration of anatomical, skin-based, and external, posture-based information. In contrast, previous studies have suggested that congenitally blind humans, by default, refrain from automatic spatial integration and localize touch using only skin-based information. Here, sighted and congenitally blind participants localized tactile targets on the palm or back of one hand, while ignoring simultaneous tactile distractors at congruent or incongruent locations on the other hand. We probed the interplay of anatomical and external location codes for spatial congruency effects by varying hand posture: the palms either both faced down, or one faced down and one up. In the latter posture, externally congruent target and distractor locations were anatomically incongruent and vice versa. Target locations had to be reported either anatomically ("palm" or "back" of the hand, or externally ("up" or "down" in space. Under anatomical instructions, performance was more accurate for anatomically congruent than incongruent target-distractor pairs. In contrast, under external instructions, performance was more accurate for externally congruent than incongruent pairs. These modulations were evident in sighted and blind individuals. Notably, distractor effects were overall far smaller in blind than in sighted participants, despite comparable target-distractor identification performance. Thus, the absence of developmental vision seems to be associated with an increased ability to focus tactile attention towards a non-spatially defined target. Nevertheless, that blind individuals exhibited effects of hand posture and task instructions in their congruency effects suggests that, like the sighted, they automatically integrate anatomical and external information during tactile localization. Moreover, spatial integration in tactile processing is, thus, flexibly

  7. Task demands affect spatial reference frame weighting during tactile localization in sighted and congenitally blind adults.

    Science.gov (United States)

    Schubert, Jonathan T W; Badde, Stephanie; Röder, Brigitte; Heed, Tobias

    2017-01-01

    Task demands modulate tactile localization in sighted humans, presumably through weight adjustments in the spatial integration of anatomical, skin-based, and external, posture-based information. In contrast, previous studies have suggested that congenitally blind humans, by default, refrain from automatic spatial integration and localize touch using only skin-based information. Here, sighted and congenitally blind participants localized tactile targets on the palm or back of one hand, while ignoring simultaneous tactile distractors at congruent or incongruent locations on the other hand. We probed the interplay of anatomical and external location codes for spatial congruency effects by varying hand posture: the palms either both faced down, or one faced down and one up. In the latter posture, externally congruent target and distractor locations were anatomically incongruent and vice versa. Target locations had to be reported either anatomically ("palm" or "back" of the hand), or externally ("up" or "down" in space). Under anatomical instructions, performance was more accurate for anatomically congruent than incongruent target-distractor pairs. In contrast, under external instructions, performance was more accurate for externally congruent than incongruent pairs. These modulations were evident in sighted and blind individuals. Notably, distractor effects were overall far smaller in blind than in sighted participants, despite comparable target-distractor identification performance. Thus, the absence of developmental vision seems to be associated with an increased ability to focus tactile attention towards a non-spatially defined target. Nevertheless, that blind individuals exhibited effects of hand posture and task instructions in their congruency effects suggests that, like the sighted, they automatically integrate anatomical and external information during tactile localization. Moreover, spatial integration in tactile processing is, thus, flexibly adapted by top

  8. Effects of distractors on upright balance performance in school-aged children with attention deficit hyperactivity disorder, preliminary study.

    Science.gov (United States)

    Aydinli, Fatma Esen; Çak, Tuna; Kirazli, Meltem Çiğdem; Çinar, Betül Çiçek; Pektaş, Alev; Çengel, Ebru Kültür; Aksoy, Songül

    2016-11-17

    Attention deficit hyperactivity disorder is a common impairing neuropsychiatric disorder with onset in early childhood. Almost half of the children with attention deficit hyperactivity disorder also experience a variety of motor-related dysfunctions ranging from fine/gross motor control problems to difficulties in maintaining balance. The main purpose of this study was to investigate the effects of distractors two different auditory distractors namely, relaxing music and white noise on upright balance performance in children with attention deficit hyperactivity disorder. We compared upright balance performance and the involvement of different sensory systems in the presence of auditory distractors between school-aged children with attention deficit hyperactivity disorder (n=26) and typically developing controls (n=20). Neurocom SMART Balance Master Dynamic Posturography device was used for the sensory organization test. Sensory organization test was repeated three times for each participant in three different test environments. The balance scores in the silence environment were lower in the attention deficit hyperactivity disorder group but the differences were not statistically significant. In addition to lower balance scores the visual and vestibular ratios were also lower. Auditory distractors affected the general balance performance positively for both groups. More challenging conditions, using an unstable platform with distorted somatosensory signals were more affected. Relaxing music was more effective in the control group, and white noise was more effective in the attention deficit hyperactivity disorder group and the positive effects of white noise became more apparent in challenging conditions. To the best of our knowledge, this is the first study evaluating balance performance in children with attention deficit hyperactivity disorder under the effects of auditory distractors. Although more studies are needed, our results indicate that auditory distractors

  9. Social Groups Prioritize Selective Attention to Faces: How Social Identity Shapes Distractor Interference.

    Directory of Open Access Journals (Sweden)

    Gewnhi Park

    Full Text Available Human faces automatically attract visual attention and this process appears to be guided by social group memberships. In two experiments, we examined how social groups guide selective attention toward in-group and out-group faces. Black and White participants detected a target letter among letter strings superimposed on faces (Experiment 1. White participants were less accurate on trials with racial out-group (Black compared to in-group (White distractor faces. Likewise, Black participants were less accurate on trials with racial out-group (White compared to in-group (Black distractor faces. However, this pattern of out-group bias was only evident under high perceptual load-when the task was visually difficult. To examine the malleability of this pattern of racial bias, a separate sample of participants were assigned to mixed-race minimal groups (Experiment 2. Participants assigned to groups were less accurate on trials with their minimal in-group members compared to minimal out-group distractor faces, regardless of race. Again, this pattern of out-group bias was only evident under high perceptual load. Taken together, these results suggest that social identity guides selective attention toward motivationally relevant social groups-shifting from out-group bias in the domain of race to in-group bias in the domain of minimal groups-when perceptual resources are scarce.

  10. Scopolamine Reduces Electrophysiological Indices of Distractor Suppression: Evidence from a Contingent Capture Task

    Directory of Open Access Journals (Sweden)

    Inga Laube

    2017-12-01

    Full Text Available Limited resources for the in-depth processing of external stimuli make it necessary to select only relevant information from our surroundings and to ignore irrelevant stimuli. Attentional mechanisms facilitate this selection via top-down modulation of stimulus representations in the brain. Previous research has indicated that acetylcholine (ACh modulates this influence of attention on stimulus processing. However, the role of muscarinic receptors as well as the specific mechanism of cholinergic modulation remains unclear. Here we investigated the influence of ACh on feature-based, top-down control of stimulus processing via muscarinic receptors by using a contingent capture paradigm which specifically tests attentional shifts toward uninformative cue stimuli which display one of the target defining features In a double-blind, placebo controlled study we measured the impact of the muscarinic receptor antagonist scopolamine on behavioral and electrophysiological measures of contingent attentional capture. The results demonstrated all the signs of functional contingent capture, i.e., attentional shifts toward cued locations reflected in increased amplitudes of N1 and N2Pc components, under placebo conditions. However, scopolamine did not affect behavioral or electrophysiological measures of contingent capture. Instead, scopolamine reduced the amplitude of the distractor-evoked Pd component which has recently been associated with active suppression of irrelevant distractor information. The findings suggest a general cholinergic modulation of top-down control during distractor processing.

  11. Dynamics Modeling and Analysis of Local Fault of Rolling Element Bearing

    Directory of Open Access Journals (Sweden)

    Lingli Cui

    2015-01-01

    Full Text Available This paper presents a nonlinear vibration model of rolling element bearings with 5 degrees of freedom based on Hertz contact theory and relevant bearing knowledge of kinematics and dynamics. The slipping of ball, oil film stiffness, and the nonlinear time-varying stiffness of the bearing are taken into consideration in the model proposed here. The single-point local fault model of rolling element bearing is introduced into the nonlinear model with 5 degrees of freedom according to the loss of the contact deformation of ball when it rolls into and out of the local fault location. The functions of spall depth corresponding to defects of different shapes are discussed separately in this paper. Then the ode solver in Matlab is adopted to perform a numerical solution on the nonlinear vibration model to simulate the vibration response of the rolling elements bearings with local fault. The simulation signals analysis results show a similar behavior and pattern to that observed in the processed experimental signals of rolling element bearings in both time domain and frequency domain which validated the nonlinear vibration model proposed here to generate typical rolling element bearings local fault signals for possible and effective fault diagnostic algorithms research.

  12. Elemental transport coefficients in viscous plasma flows near local thermodynamic equilibrium

    International Nuclear Information System (INIS)

    Orsini, Alessio; Kustova, Elena V.

    2009-01-01

    We propose a convenient formulation of elemental transport coefficients in chemically reacting and plasma flows locally approaching thermodynamic equilibrium. A set of transport coefficients for elemental diffusion velocities, heat flux, and electric current is introduced. These coefficients relate the transport fluxes with the electric field and with the spatial gradients of elemental fractions, pressure, and temperature. The proposed formalism based on chemical elements and fully symmetric with the classical transport theory based on chemical species, is particularly suitable to model mixing and demixing phenomena due to diffusion of chemical elements. The aim of this work is threefold: to define a simple and rigorous framework suitable for numerical implementation, to allow order of magnitude estimations and qualitative predictions of elemental transport phenomena, and to gain a deeper insight into the physics of chemically reacting flows near local equilibrium.

  13. Attentional bias to briefly presented emotional distractors follows a slow time course in visual cortex.

    Science.gov (United States)

    Müller, Matthias M; Andersen, Søren K; Hindi Attar, Catherine

    2011-11-02

    A central controversy in the field of attention is how the brain deals with emotional distractors and to what extent they capture attentional processing resources reflexively due to their inherent significance for guidance of adaptive behavior and survival. Especially, the time course of competitive interactions in early visual areas and whether masking of briefly presented emotional stimuli can inhibit biasing of processing resources in these areas is currently unknown. We recorded frequency-tagged potentials evoked by a flickering target detection task in the foreground of briefly presented emotional or neutral pictures that were followed by a mask in human subjects. We observed greater competition for processing resources in early visual cortical areas with shortly presented emotional relative to neutral pictures ~275 ms after picture offset. This was paralleled by a reduction of target detection rates in trials with emotional pictures ~400 ms after picture offset. Our finding that briefly presented emotional distractors are able to bias attention well after their offset provides evidence for a rather slow feedback or reentrant neural competition mechanism for emotional distractors that continues after the offset of the emotional stimulus.

  14. Finite element analysis of the equivalent stress distribution in Schanz screws during the use of a femoral fracture distractor

    Directory of Open Access Journals (Sweden)

    Vincenzo Giordano

    Full Text Available ABSTRACT To evaluate the mechanical stress and elastic deformation exercised in the thread/shaft transition of Schanz screws in assemblies with different screw anchorage distances in the entrance to the bone cortex, through the distribution and location of tension in the samples. An analysis of 3D finite elements was performed to evaluate the distribution of the equivalent stress (triple stress state in a Schanz screw fixed bicortically and orthogonally to a tubular bone, using two mounting patterns: (1 thread/shaft transition located 20 mm from the anchorage of the Schanz screws in the entrance to the bone cortex and (2 thread/shaft transition located 3 mm from the anchorage of the Schanz screws in entrance to the bone cortex. The simulations were performed maintaining the same direction of loading and the same distance from the force vector in relation to the center of the hypothetical bone. The load applied, its direction, and the distance to the center of the bone were constant during the simulations in order to maintain the moment of flexion equally constant. The present calculations demonstrated linear behavior during the experiment. It was found that the model with a distance of 20 mm between the Schanz screws anchorage in the entrance to the bone cortex and the thread/shaft transition reduces the risk of breakage or fatigue of the material during the application of constant static loads; in this model, the maximum forces observed were higher (350 MPa. The distance between the Schanz screws anchorage at the entrance to the bone cortex and the smooth thread/shaft transition of the screws used in a femoral distractor during acute distraction of a fracture must be farther from the entrance to the bone cortex, allowing greater degree of elastic deformation of the material, lower mechanical stress in the thread/shaft transition, and minimized breakage or fatigue. The suggested distance is 20 mm.

  15. Managing a grossly comminuted and infected mandibular fracture using a maxillary extra-oral distractor as stabilizing agent: A clinical case report

    Directory of Open Access Journals (Sweden)

    Ding Ming Chao

    2017-06-01

    Full Text Available Facial fracture management dates as early as Hippocratic era. Comminuted mandibular fractures are one of the challenging clinical condition requiring high surgical expertise to achieve a good functional and esthetic outcome. In presence of infection and other facial fractures managing comminuted mandibular fracture becomes more challenging.Here we present a case of grossly comminuted and infected mandibular fracture with delayed presentation managed by using maxillary distractor as stabilizing agent. Using a maxillary distractor for managing a fractured mandible has been seldom reported in literature. Current case report gives idea to practicing clinician about the possibility of treatment beyond the established principles. Keywords: Mandibular fracture, Maxillary distractor, Infection

  16. Phonological processing of ignored distractor pictures, an fMRI investigation

    OpenAIRE

    Bles Mart; Jansma Bernadette M

    2008-01-01

    Abstract Background Neuroimaging studies of attention often focus on interactions between stimulus representations and top-down selection mechanisms in visual cortex. Less is known about the neural representation of distractor stimuli beyond visual areas, and the interactions between stimuli in linguistic processing areas. In the present study, participants viewed simultaneously presented line drawings at peripheral locations, while in the MRI scanner. The names of the objects depicted in the...

  17. Determination of Essential Elements in Local Foodstuffs of Saudi Arabian Kingdom

    International Nuclear Information System (INIS)

    Eissa, M.W.A.; Al-ahmary, Kh.M.A.

    2004-01-01

    Vegetable and fruit samples were collected from their major area of Saudi Arabian Kingdom (KSA), together with locally bred, fish and meat and local manufacture products as cheese and macaroni. These samples were analyzed for Na, K, Mg, Ca, Fe, Zn, Cu and Mn using flame photometer and atomic absorption spectrometer. The results showed that the level of Na and K in local foodstuffs not vary greatly from the reported values. But Mg showed much higher concentration than that the reported value. On the contrary the levels of Ca, Fe, Zn, Cu and Mn lower than the reported values. The daily intake of essential elements was calculated taking into account the concentration of these elements in the edible part and the daily consumption data which were derived from two sources a- the food balance sheet of Kingdom of Saudi Arabian (KSA) given by Food Agriculture Organization FAO and b-daily intake of these essential elements according to FAO are satisfy the daily requirements except Ca and Zn, But according to the questionnaire the daily intake of these elements is less than the requirements daily intake except for Mg

  18. Response of the Pre-oriented Goal-directed Attention to Usual and Unusual Distractors: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Golnaz Baghdadi

    2017-03-01

    Full Text Available Introduction: In this study, we investigated the distraction power of the unusual and usual images on the attention of 20 healthy primary school children. Methods: Our study was different from previous ones in that the participants were asked to fix the initial position of their attention on a pre-defined location after being presented with unusual images as distractors. The goals were presented in locations, which were far from the attraction basin of distractors. Our expectation was that the pre-orienting of the attention to the position of targets can reduce the attractive effect of unusual images compared to the usual ones. The percentage of correct responses and the reaction time have been measured as behavioral indicators of attention performance. Results: Results showed that using the goal-directed attention, subjects ignored both kinds of distractors nearly the same way. Conclusion: With regard to previous reports about the more attraction towards the unusual images, it is suggested that the dynamics of the visual attention system be sensitive to the initial condition. That is, changing the initial position of the attention can lead to the decrement of the unusual images’ effects. However, several other possibilities such as a probable delay in processing unusual features could explain this observation, too. 

  19. Local Refinement of the Super Element Model of Oil Reservoir

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    A.B. Mazo

    2017-12-01

    Full Text Available In this paper, we propose a two-stage method for petroleum reservoir simulation. The method uses two models with different degrees of detailing to describe hydrodynamic processes of different space-time scales. At the first stage, the global dynamics of the energy state of the deposit and reserves is modeled (characteristic scale of such changes is km / year. The two-phase flow equations in the model of global dynamics operate with smooth averaged pressure and saturation fields, and they are solved numerically on a large computational grid of super-elements with a characteristic cell size of 200-500 m. The tensor coefficients of the super-element model are calculated using special procedures of upscaling of absolute and relative phase permeabilities. At the second stage, a local refinement of the super-element model is constructed for calculating small-scale processes (with a scale of m / day, which take place, for example, during various geological and technical measures aimed at increasing the oil recovery of a reservoir. Then we solve the two-phase flow problem in the selected area of the measure exposure on a detailed three-dimensional grid, which resolves the geological structure of the reservoir, and with a time step sufficient for describing fast-flowing processes. The initial and boundary conditions of the local problem are formulated on the basis of the super-element solution. This approach allows us to reduce the computational costs in order to solve the problems of designing and monitoring the oil reservoir. To demonstrate the proposed approach, we give an example of the two-stage modeling of the development of a layered reservoir with a local refinement of the model during the isolation of a water-saturated high-permeability interlayer. We show a good compliance between the locally refined solution of the super-element model in the area of measure exposure and the results of numerical modeling of the whole history of reservoir

  20. The Effect of Task-Irrelevant Fearful-Face Distractor on Working Memory Processing in Mild Cognitive Impairment versus Healthy Controls: An Exploratory fMRI Study in Female Participants

    Directory of Open Access Journals (Sweden)

    Amer M. Burhan

    2016-01-01

    Full Text Available In mild cognitive impairment (MCI, a risk state for Alzheimer’s disease, patients have objective cognitive deficits with relatively preserved functioning. fMRI studies have identified anomalies during working memory (WM processing in individuals with MCI. The effect of task-irrelevant emotional face distractor on WM processing in MCI remains unclear. We aim to explore the impact of fearful-face task-irrelevant distractor on WM processing in MCI using fMRI. Hypothesis. Compared to healthy controls (HC, MCI patients will show significantly higher BOLD signal in a priori identified regions of interest (ROIs during a WM task with a task-irrelevant emotional face distractor. Methods. 9 right-handed female participants with MCI and 12 matched HC performed a WM task with standardized task-irrelevant fearful versus neutral face distractors randomized and counterbalanced across WM trials. MRI images were acquired during the WM task and BOLD signal was analyzed using statistical parametric mapping (SPM to identify signal patterns during the task response phase. Results. Task-irrelevant fearful-face distractor resulted in higher activation in the amygdala, anterior cingulate, and frontal areas, in MCI participants compared to HC. Conclusions. This exploratory study suggests altered WM processing as a result of fearful-face distractor in MCI.

  1. Protecting visual short-term memory during maintenance : Attentional modulation of target and distractor representations

    NARCIS (Netherlands)

    Vissers, M.E.; Gulbinaite, R.; van den Bos, T.; Slagter, H.A.

    2017-01-01

    In the presence of distraction, attentional filtering is a key predictor of efficient information storage in visual short-term memory (VSTM). Yet, the role of attention in distractor filtering, and the extent to which attentional filtering continues to protect information during post-perceptual

  2. Developmental Differences in the Influence of Distractors on Maintenance in Spatial Working Memory

    Science.gov (United States)

    Schutte, Anne R.; Keiser, Brian A.; Beattie, Heidi L.

    2017-01-01

    This study examined whether attention to a location plays a role in the maintenance of locations in spatial working memory in young children as it does in adults. This study was the first to investigate whether distractors presented during the delay of a spatial working-memory task influenced young children's memory responses. Across 2…

  3. Working-memory capacity predicts the executive control of visual search among distractors: the influences of sustained and selective attention.

    Science.gov (United States)

    Poole, Bradley J; Kane, Michael J

    2009-07-01

    Variation in working-memory capacity (WMC) predicts individual differences in only some attention-control capabilities. Whereas higher WMC subjects outperform lower WMC subjects in tasks requiring the restraint of prepotent but inappropriate responses, and the constraint of attentional focus to target stimuli against distractors, they do not differ in prototypical visual-search tasks, even those that yield steep search slopes and engender top-down control. The present three experiments tested whether WMC, as measured by complex memory span tasks, would predict search latencies when the 1-8 target locations to be searched appeared alone, versus appearing among distractor locations to be ignored, with the latter requiring selective attentional focus. Subjects viewed target-location cues and then fixated on those locations over either long (1,500-1,550 ms) or short (300 ms) delays. Higher WMC subjects identified targets faster than did lower WMC subjects only in the presence of distractors and only over long fixation delays. WMC thus appears to affect subjects' ability to maintain a constrained attentional focus over time.

  4. Comparison of Subset-Based Local and Finite Element-Based Global Digital Image Correlation

    KAUST Repository

    Pan, Bing; Wang, B.; Lubineau, Gilles; Moussawi, Ali

    2015-01-01

    Digital image correlation (DIC) techniques require an image matching algorithm to register the same physical points represented in different images. Subset-based local DIC and finite element-based (FE-based) global DIC are the two primary image matching methods that have been extensively investigated and regularly used in the field of experimental mechanics. Due to its straightforward implementation and high efficiency, subset-based local DIC has been used in almost all commercial DIC packages. However, it is argued by some researchers that FE-based global DIC offers better accuracy because of the enforced continuity between element nodes. We propose a detailed performance comparison between these different DIC algorithms both in terms of measurement accuracy and computational efficiency. Then, by measuring displacements of the same calculation points using the same calculation algorithms (e.g., correlation criterion, initial guess estimation, subpixel interpolation, optimization algorithm and convergence conditions) and identical calculation parameters (e.g., subset or element size), the performances of subset-based local DIC and two FE-based global DIC approaches are carefully compared in terms of measurement error and computational efficiency using both numerical tests and real experiments. A detailed examination of the experimental results reveals that, when subset (element) size is not very small and the local deformation within a subset (element) can be well approximated by the shape function used, standard subset-based local DIC approach not only provides better results in measured displacements, but also demonstrates much higher computation efficiency. However, several special merits of FE-based global DIC approaches are indicated.

  5. Comparison of Subset-Based Local and Finite Element-Based Global Digital Image Correlation

    KAUST Repository

    Pan, Bing

    2015-02-12

    Digital image correlation (DIC) techniques require an image matching algorithm to register the same physical points represented in different images. Subset-based local DIC and finite element-based (FE-based) global DIC are the two primary image matching methods that have been extensively investigated and regularly used in the field of experimental mechanics. Due to its straightforward implementation and high efficiency, subset-based local DIC has been used in almost all commercial DIC packages. However, it is argued by some researchers that FE-based global DIC offers better accuracy because of the enforced continuity between element nodes. We propose a detailed performance comparison between these different DIC algorithms both in terms of measurement accuracy and computational efficiency. Then, by measuring displacements of the same calculation points using the same calculation algorithms (e.g., correlation criterion, initial guess estimation, subpixel interpolation, optimization algorithm and convergence conditions) and identical calculation parameters (e.g., subset or element size), the performances of subset-based local DIC and two FE-based global DIC approaches are carefully compared in terms of measurement error and computational efficiency using both numerical tests and real experiments. A detailed examination of the experimental results reveals that, when subset (element) size is not very small and the local deformation within a subset (element) can be well approximated by the shape function used, standard subset-based local DIC approach not only provides better results in measured displacements, but also demonstrates much higher computation efficiency. However, several special merits of FE-based global DIC approaches are indicated.

  6. On the electron density localization in elemental cubic ceramic and FCC transition metals by means of a localized electrons detector.

    Science.gov (United States)

    Aray, Yosslen; Paredes, Ricardo; Álvarez, Luis Javier; Martiz, Alejandro

    2017-06-14

    The electron density localization in insulator and semiconductor elemental cubic materials with diamond structure, carbon, silicon, germanium, and tin, and good metallic conductors with face centered cubic structure such as α-Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au, was studied using a localized electrons detector defined in the local moment representation. Our results clearly show an opposite pattern of the electron density localization for the cubic ceramic and transition metal materials. It was found that, for the elemental ceramic materials, the zone of low electron localization is very small and is mainly localized on the atomic basin edges. On the contrary, for the transition metals, there are low-valued localized electrons detector isocontours defining a zone of highly delocalized electrons that extends throughout the material. We have found that the best conductors are those in which the electron density at this low-value zone is the lowest.

  7. Infants' Selective Attention to Reliable Visual Cues in the Presence of Salient Distractors

    Science.gov (United States)

    Tummeltshammer, Kristen Swan; Mareschal, Denis; Kirkham, Natasha Z.

    2014-01-01

    With many features competing for attention in their visual environment, infants must learn to deploy attention toward informative cues while ignoring distractions. Three eye tracking experiments were conducted to investigate whether 6- and 8-month-olds (total N = 102) would shift attention away from a distractor stimulus to learn a cue-reward…

  8. A new palatal distractor device for bodily movement of maxillary bones by rigid self-locking miniplates and screws system.

    Science.gov (United States)

    Cortese, Antonio; Savastano, Mauro; Cantone, Antonio; Claudio, Pier Paolo

    2013-07-01

    A new palatal distractor device for bodily movement of the maxillary bones after complete segmented Le Fort I osteotomy for 1-stage transversal distraction and tridimensional repositioning on 1 patient is presented. The new distractor has an intrinsic tridimensional rigidity also in the fixation system by self-locking miniplates and screws for better control of the 2 maxillary fragments during distraction. Le Fort I distraction and repositioning procedure in association with a bilateral sagittal split osteotomy were performed on 1 patient with complete solution of the cross-bite and class III malocclusion. Results of dental and cephalometric analysis performed before surgery (T1), after surgery and distraction time (T2), and 18 months after surgery and orthodontic appliance removal (T3) are reported. No complications were encountered using the new distractor device. Advantages of this device and technique are presented including improved rigidity of both distraction (jackscrew) and fixation (4 self-locking miniplates and screws) systems resulting in complete control of the position of the 2 maxillary fragments during distraction and surgery. In addition, this new device allows resuming palatal distraction in the event of cross-bite relapse without causing dental-related problems or the risks of screw slackening.

  9. Selective attention to task-irrelevant emotional distractors is unaffected by the perceptual load associated with a foreground task.

    Science.gov (United States)

    Hindi Attar, Catherine; Müller, Matthias M

    2012-01-01

    A number of studies have shown that emotionally arousing stimuli are preferentially processed in the human brain. Whether or not this preference persists under increased perceptual load associated with a task at hand remains an open question. Here we manipulated two possible determinants of the attentional selection process, perceptual load associated with a foreground task and the emotional valence of concurrently presented task-irrelevant distractors. As a direct measure of sustained attentional resource allocation in early visual cortex we used steady-state visual evoked potentials (SSVEPs) elicited by distinct flicker frequencies of task and distractor stimuli. Subjects either performed a detection (low load) or discrimination (high load) task at a centrally presented symbol stream that flickered at 8.6 Hz while task-irrelevant neutral or unpleasant pictures from the International Affective Picture System (IAPS) flickered at a frequency of 12 Hz in the background of the stream. As reflected in target detection rates and SSVEP amplitudes to both task and distractor stimuli, unpleasant relative to neutral background pictures more strongly withdrew processing resources from the foreground task. Importantly, this finding was unaffected by the factor 'load' which turned out to be a weak modulator of attentional processing in human visual cortex.

  10. Selective attention to task-irrelevant emotional distractors is unaffected by the perceptual load associated with a foreground task.

    Directory of Open Access Journals (Sweden)

    Catherine Hindi Attar

    Full Text Available A number of studies have shown that emotionally arousing stimuli are preferentially processed in the human brain. Whether or not this preference persists under increased perceptual load associated with a task at hand remains an open question. Here we manipulated two possible determinants of the attentional selection process, perceptual load associated with a foreground task and the emotional valence of concurrently presented task-irrelevant distractors. As a direct measure of sustained attentional resource allocation in early visual cortex we used steady-state visual evoked potentials (SSVEPs elicited by distinct flicker frequencies of task and distractor stimuli. Subjects either performed a detection (low load or discrimination (high load task at a centrally presented symbol stream that flickered at 8.6 Hz while task-irrelevant neutral or unpleasant pictures from the International Affective Picture System (IAPS flickered at a frequency of 12 Hz in the background of the stream. As reflected in target detection rates and SSVEP amplitudes to both task and distractor stimuli, unpleasant relative to neutral background pictures more strongly withdrew processing resources from the foreground task. Importantly, this finding was unaffected by the factor 'load' which turned out to be a weak modulator of attentional processing in human visual cortex.

  11. Classification of Targets and Distractors Present in Visual Hemifields Using Time-Frequency Domain EEG Features

    Directory of Open Access Journals (Sweden)

    Sweeti

    2018-01-01

    Full Text Available This paper presents a classification system to classify the cognitive load corresponding to targets and distractors present in opposite visual hemifields. The approach includes the study of EEG (electroencephalogram signal features acquired in a spatial attention task. The process comprises of EEG feature selection based on the feature distribution, followed by the stepwise discriminant analysis- (SDA- based channel selection. Repeated measure analysis of variance (rANOVA is applied to test the statistical significance of the selected features. Classifiers are developed and compared using the selected features to classify the target and distractor present in visual hemifields. The results provide a maximum classification accuracy of 87.2% and 86.1% and an average classification accuracy of 76.5 ± 4% and 76.2 ± 5.3% over the thirteen subjects corresponding to the two task conditions. These correlates present a step towards building a feature-based neurofeedback system for visual attention.

  12. Errorless learning and working memory: the impact of errors, distractors, and memory span load on immediate recall in healthy adults.

    Science.gov (United States)

    Nordvik, Jan E; Schanke, Anne-Kristine; Landro, Nils I

    2011-06-01

    Errorless learning represents an important contribution to current neuropsychological rehabilitation. Previous research has mainly explained the benefits of errorless learning through properties of long-term memory. This study aims to explore how errors affect immediate recall performance. A new, supplementary perspective focusing on the role of working memory in errorless learning is introduced. Sixty university students participated in a within-subject design experiment measuring the effect of errors, memory span load, and attentional distractors on a digit recall task. Errors were found to have significant negative impact on immediate recall, while distractors had an effect only in interaction with errors.

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

    Science.gov (United States)

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

    2014-01-01

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

  14. Distractor Effect of Auditory Rhythms on Self-Paced Tapping in Chimpanzees and Humans.

    Science.gov (United States)

    Hattori, Yuko; Tomonaga, Masaki; Matsuzawa, Tetsuro

    2015-01-01

    Humans tend to spontaneously align their movements in response to visual (e.g., swinging pendulum) and auditory rhythms (e.g., hearing music while walking). Particularly in the case of the response to auditory rhythms, neuroscientific research has indicated that motor resources are also recruited while perceiving an auditory rhythm (or regular pulse), suggesting a tight link between the auditory and motor systems in the human brain. However, the evolutionary origin of spontaneous responses to auditory rhythms is unclear. Here, we report that chimpanzees and humans show a similar distractor effect in perceiving isochronous rhythms during rhythmic movement. We used isochronous auditory rhythms as distractor stimuli during self-paced alternate tapping of two keys of an electronic keyboard by humans and chimpanzees. When the tempo was similar to their spontaneous motor tempo, tapping onset was influenced by intermittent entrainment to auditory rhythms. Although this effect itself is not an advanced rhythmic ability such as dancing or singing, our results suggest that, to some extent, the biological foundation for spontaneous responses to auditory rhythms was already deeply rooted in the common ancestor of chimpanzees and humans, 6 million years ago. This also suggests the possibility of a common attentional mechanism, as proposed by the dynamic attending theory, underlying the effect of perceiving external rhythms on motor movement.

  15. Lumped Mass Modeling for Local-Mode-Suppressed Element Connectivity

    DEFF Research Database (Denmark)

    Joung, Young Soo; Yoon, Gil Ho; Kim, Yoon Young

    2005-01-01

    connectivity parameterization (ECP) is employed. On the way to the ultimate crashworthy structure optimization, we are now developing a local mode-free topology optimization formulation that can be implemented in the ECP method. In fact, the local mode-freeing strategy developed here can be also used directly...... experiencing large structural changes, appears to be still poor. In ECP, the nodes of the domain-discretizing elements are connected by zero-length one-dimensional elastic links having varying stiffness. For computational efficiency, every elastic link is now assumed to have two lumped masses at its ends....... Choosing appropriate penalization functions for lumped mass and link stiffness is important for local mode-free results. However, unless the objective and constraint functions are carefully selected, it is difficult to obtain clear black-and-white results. It is shown that the present formulation is also...

  16. Difference in Perseverative Errors during a Visual Attention Task with Auditory Distractors in Alpha-9 Nicotinic Receptor Subunit Wild Type and Knock-Out Mice.

    Science.gov (United States)

    Jorratt, Pascal; Delano, Paul H; Delgado, Carolina; Dagnino-Subiabre, Alexies; Terreros, Gonzalo

    2017-01-01

    The auditory efferent system is a neural network that originates in the auditory cortex and projects to the cochlear receptor through olivocochlear (OC) neurons. Medial OC neurons make cholinergic synapses with outer hair cells (OHCs) through nicotinic receptors constituted by α9 and α10 subunits. One of the physiological functions of the α9 nicotinic receptor subunit (α9-nAChR) is the suppression of auditory distractors during selective attention to visual stimuli. In a recent study we demonstrated that the behavioral performance of alpha-9 nicotinic receptor knock-out (KO) mice is altered during selective attention to visual stimuli with auditory distractors since they made less correct responses and more omissions than wild type (WT) mice. As the inhibition of the behavioral responses to irrelevant stimuli is an important mechanism of the selective attention processes, behavioral errors are relevant measures that can reflect altered inhibitory control. Errors produced during a cued attention task can be classified as premature, target and perseverative errors. Perseverative responses can be considered as an inability to inhibit the repetition of an action already planned, while premature responses can be considered as an index of the ability to wait or retain an action. Here, we studied premature, target and perseverative errors during a visual attention task with auditory distractors in WT and KO mice. We found that α9-KO mice make fewer perseverative errors with longer latencies than WT mice in the presence of auditory distractors. In addition, although we found no significant difference in the number of target error between genotypes, KO mice made more short-latency target errors than WT mice during the presentation of auditory distractors. The fewer perseverative error made by α9-KO mice could be explained by a reduced motivation for reward and an increased impulsivity during decision making with auditory distraction in KO mice.

  17. Distractor Effect of Auditory Rhythms on Self-Paced Tapping in Chimpanzees and Humans

    Science.gov (United States)

    Hattori, Yuko; Tomonaga, Masaki; Matsuzawa, Tetsuro

    2015-01-01

    Humans tend to spontaneously align their movements in response to visual (e.g., swinging pendulum) and auditory rhythms (e.g., hearing music while walking). Particularly in the case of the response to auditory rhythms, neuroscientific research has indicated that motor resources are also recruited while perceiving an auditory rhythm (or regular pulse), suggesting a tight link between the auditory and motor systems in the human brain. However, the evolutionary origin of spontaneous responses to auditory rhythms is unclear. Here, we report that chimpanzees and humans show a similar distractor effect in perceiving isochronous rhythms during rhythmic movement. We used isochronous auditory rhythms as distractor stimuli during self-paced alternate tapping of two keys of an electronic keyboard by humans and chimpanzees. When the tempo was similar to their spontaneous motor tempo, tapping onset was influenced by intermittent entrainment to auditory rhythms. Although this effect itself is not an advanced rhythmic ability such as dancing or singing, our results suggest that, to some extent, the biological foundation for spontaneous responses to auditory rhythms was already deeply rooted in the common ancestor of chimpanzees and humans, 6 million years ago. This also suggests the possibility of a common attentional mechanism, as proposed by the dynamic attending theory, underlying the effect of perceiving external rhythms on motor movement. PMID:26132703

  18. Visual Working Memory Capacity Can Be Increased by Training on Distractor Filtering Efficiency.

    Science.gov (United States)

    Li, Cui-Hong; He, Xu; Wang, Yu-Juan; Hu, Zhe; Guo, Chun-Yan

    2017-01-01

    It is generally considered that working memory (WM) capacity is limited and that WM capacity affects cognitive processes. Distractor filtering efficiency has been suggested to be an important factor in determining the visual working memory (VWM) capacity of individuals. In the present study, we investigated whether training in visual filtering efficiency (FE) could improve VWM capacity, as measured by performance on the change detection task (CDT) and changes of contralateral delay activity (CDA) (contralateral delay activity) of different conditions, and evaluated the transfer effect of visual FE training on verbal WM and fluid intelligence, as indexed by performance on the verbal WM span task and Raven's Standard Progressive Matrices (RSPM) test, respectively. Participants were divided into high- and low-capacity groups based on their performance in a CDT designed to test VWM capacity, and then the low-capacity individuals received 20 days of FE training. The training significantly improved the group's performance in the CDT, and their CDA models of different conditions became more similar with high capacity group, and the effect generalized to improve verbal WM span. These gains were maintained at a 3-month follow-up test. Participants' RSPM scores were not changed by the training. These findings support the notion that WM capacity is determined, at least in part, by distractor FE and can be enhanced through training.

  19. Distractor Effect of Auditory Rhythms on Self-Paced Tapping in Chimpanzees and Humans.

    Directory of Open Access Journals (Sweden)

    Yuko Hattori

    Full Text Available Humans tend to spontaneously align their movements in response to visual (e.g., swinging pendulum and auditory rhythms (e.g., hearing music while walking. Particularly in the case of the response to auditory rhythms, neuroscientific research has indicated that motor resources are also recruited while perceiving an auditory rhythm (or regular pulse, suggesting a tight link between the auditory and motor systems in the human brain. However, the evolutionary origin of spontaneous responses to auditory rhythms is unclear. Here, we report that chimpanzees and humans show a similar distractor effect in perceiving isochronous rhythms during rhythmic movement. We used isochronous auditory rhythms as distractor stimuli during self-paced alternate tapping of two keys of an electronic keyboard by humans and chimpanzees. When the tempo was similar to their spontaneous motor tempo, tapping onset was influenced by intermittent entrainment to auditory rhythms. Although this effect itself is not an advanced rhythmic ability such as dancing or singing, our results suggest that, to some extent, the biological foundation for spontaneous responses to auditory rhythms was already deeply rooted in the common ancestor of chimpanzees and humans, 6 million years ago. This also suggests the possibility of a common attentional mechanism, as proposed by the dynamic attending theory, underlying the effect of perceiving external rhythms on motor movement.

  20. Energy-time entanglement, elements of reality, and local realism

    Science.gov (United States)

    Jogenfors, Jonathan; Larsson, Jan-Åke

    2014-10-01

    The Franson interferometer, proposed in 1989 (Franson 1989 Phys. Rev. Lett. 62 2205-08), beautifully shows the counter-intuitive nature of light. The quantum description predicts sinusoidal interference for specific outcomes of the experiment, and these predictions can be verified in experiment. In the spirit of Einstein, Podolsky, and Rosen it is possible to ask if the quantum-mechanical description (of this setup) can be considered complete. This question will be answered in detail in this paper, by delineating the quite complicated relation between energy-time entanglement experiments and Einstein-Podolsky-Rosen (EPR) elements of reality. The mentioned sinusoidal interference pattern is the same as that giving a violation in the usual Bell experiment. Even so, depending on the precise requirements made on the local realist model, this can imply (a) no violation, (b) smaller violation than usual, or (c) full violation of the appropriate statistical bound. Alternatives include (a) using only the measurement outcomes as EPR elements of reality, (b) using the emission time as EPR element of reality, (c) using path realism, or (d) using a modified setup. This paper discusses the nature of these alternatives and how to choose between them. The subtleties of this discussion needs to be taken into account when designing and setting up experiments intended to test local realism. Furthermore, these considerations are also important for quantum communication, for example in Bell-inequality-based quantum cryptography, especially when aiming for device independence. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘50 years of Bell’s theorem’.

  1. Energy-time entanglement, elements of reality, and local realism

    International Nuclear Information System (INIS)

    Jogenfors, Jonathan; Larsson, Jan-Åke

    2014-01-01

    The Franson interferometer, proposed in 1989 (Franson 1989 Phys. Rev. Lett. 62 2205–08), beautifully shows the counter-intuitive nature of light. The quantum description predicts sinusoidal interference for specific outcomes of the experiment, and these predictions can be verified in experiment. In the spirit of Einstein, Podolsky, and Rosen it is possible to ask if the quantum-mechanical description (of this setup) can be considered complete. This question will be answered in detail in this paper, by delineating the quite complicated relation between energy-time entanglement experiments and Einstein–Podolsky–Rosen (EPR) elements of reality. The mentioned sinusoidal interference pattern is the same as that giving a violation in the usual Bell experiment. Even so, depending on the precise requirements made on the local realist model, this can imply (a) no violation, (b) smaller violation than usual, or (c) full violation of the appropriate statistical bound. Alternatives include (a) using only the measurement outcomes as EPR elements of reality, (b) using the emission time as EPR element of reality, (c) using path realism, or (d) using a modified setup. This paper discusses the nature of these alternatives and how to choose between them. The subtleties of this discussion needs to be taken into account when designing and setting up experiments intended to test local realism. Furthermore, these considerations are also important for quantum communication, for example in Bell-inequality-based quantum cryptography, especially when aiming for device independence. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘50 years of Bell’s theorem’. (paper)

  2. Difference in Perseverative Errors during a Visual Attention Task with Auditory Distractors in Alpha-9 Nicotinic Receptor Subunit Wild Type and Knock-Out Mice

    Directory of Open Access Journals (Sweden)

    Pascal Jorratt

    2017-11-01

    Full Text Available The auditory efferent system is a neural network that originates in the auditory cortex and projects to the cochlear receptor through olivocochlear (OC neurons. Medial OC neurons make cholinergic synapses with outer hair cells (OHCs through nicotinic receptors constituted by α9 and α10 subunits. One of the physiological functions of the α9 nicotinic receptor subunit (α9-nAChR is the suppression of auditory distractors during selective attention to visual stimuli. In a recent study we demonstrated that the behavioral performance of alpha-9 nicotinic receptor knock-out (KO mice is altered during selective attention to visual stimuli with auditory distractors since they made less correct responses and more omissions than wild type (WT mice. As the inhibition of the behavioral responses to irrelevant stimuli is an important mechanism of the selective attention processes, behavioral errors are relevant measures that can reflect altered inhibitory control. Errors produced during a cued attention task can be classified as premature, target and perseverative errors. Perseverative responses can be considered as an inability to inhibit the repetition of an action already planned, while premature responses can be considered as an index of the ability to wait or retain an action. Here, we studied premature, target and perseverative errors during a visual attention task with auditory distractors in WT and KO mice. We found that α9-KO mice make fewer perseverative errors with longer latencies than WT mice in the presence of auditory distractors. In addition, although we found no significant difference in the number of target error between genotypes, KO mice made more short-latency target errors than WT mice during the presentation of auditory distractors. The fewer perseverative error made by α9-KO mice could be explained by a reduced motivation for reward and an increased impulsivity during decision making with auditory distraction in KO mice.

  3. Development of geological disposal system; localization of element cost data and cost evaluation on the HLW repository

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byung Sik; Kim, Kil Jung; Yang, Young Jin; Kim, Sung Chun [KOPEC, Taejeon (Korea)

    2002-03-01

    To estimate Total Life Cycle Cost (TSLCC) for Korea HLW Repository through localization of element cost data, we review and re-organize each basic element cost data for reference repository system, localize various element cost and finally estimate TSLCC considering economic parameters. As results of the study, TSLCC is estimated as 17,167,689 million won, which includes costs for site preparation, surface facilities, underground facilities and management/integration. Since HLW repository Project is an early stage of pre-conceptual design at present, the information of design and project information are not enough to perform cost estimate and cost localization for the Project. However, project cost structure is re-organized based on the local condition and Total System Life Cycle Cost is estimated using the previous cost data gathered from construction experience of the local nuclear power plant. Project results can be used as basic reference data to assume total construction cost for the local HLW repository and should be revised to more reliable cost data with incorporating detail project design information into the cost estimate in a future. 20 refs. (Author)

  4. Towards a unified solution of localization failure with mixed finite elements

    Science.gov (United States)

    Benedetti, Lorenzo; Cervera, Miguel; Chiumenti, Michele; Zeidler, Antonia; Fischer, Jan-Thomas

    2015-04-01

    Notwithstanding computational scientists made significant steps in the numerical simulation of failure in last three decades, the strain localization problem is still an open question. Especially in a geotechnical setting, when dealing with stability analysis of slopes, it is necessary to provide correct distribution of displacements, to evaluate the stresses in the ground and, therefore, to be able to identify the slip lines that brings to progressive collapse of the slope. Finite elements are an attractive method of solution thanks to profound mathematical foundations and the possibility of describing generic geometries. In order to account for the onset of localization band, the smeared crack approach [1] is introduced, that is the strain localization is assumed to occur in a band of finite width where the displacements are continuous and the strains are discontinuous but bounded. It is well known that this kind of approach poses some challenges. The standard irreducible formulation of FEM is known to be heavily affected by spurious mesh dependence when softening behavior occurs and, consequently, slip lines evolution is biased by the orientation of the mesh. Moreover, in the case of isochoric behavior, unbounded pressure oscillations arise and the consequent locking of the stresses pollutes the numerical solution. Both problems can be shown not to be related to the mathematical statement of the continuous problem but instead to its discrete (FEM) counterpart. Mixed finite element formulations represent a suitable alternative to mitigate these drawbacks. As it has been shown in previous works by Cervera [2], a mixed formulation in terms of displacements and pressure not only provides a propitious solution to the problem of incompressibility, but also it was found to possess the needed robustness in case of strain concentration. This presentation introduces a (stabilized) mixed finite element formulation with continuous linear strain and displacement

  5. Precise positioning of an intraoral distractor using augmented reality in patients with hemifacial microsomia.

    Science.gov (United States)

    Qu, Miao; Hou, Yikang; Xu, Yourong; Shen, Congcong; Zhu, Ming; Xie, Le; Wang, Hao; Zhang, Yan; Chai, Gang

    2015-01-01

    Through three-dimensional real time imaging, augmented reality (AR) can provide an overlay of the anatomical structure, or visual cues for specific landmarks. In this study, an AR Toolkit was used for distraction osteogenesis with hemifacial microsomia to define the mandibular osteotomy line and assist with intraoral distractor placement. 20 patients with hemifacial microsomia were studied and were randomly assigned to experimental and control groups. Pre-operative computed tomography was used in both groups, whereas AR was used in the experimental group. Afterwards, pre- and post-operative computed tomographic scans of both groups were superimposed, and several measurements were made and analysed. Both the conventional method and AR technique achieved proper positioning of the osteotomy planes, although the AR was more accurate. The difference in average vertical distance from the coronoid and condyle process to the pre- and post-operative cutting planes was significant (p 0.05) was observed in the average angle between the two planes. The difference in deviations between the intersection points of the overlaid mandible across two cutting planes was also significant (p Augmented reality tools such as the AR Toolkit may be helpful for precise positioning of intraoral distractors in patients with hemifacial microsomia in craniofacial surgery. Copyright © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  6. Genetic local search algorithm for optimization design of diffractive optical elements.

    Science.gov (United States)

    Zhou, G; Chen, Y; Wang, Z; Song, H

    1999-07-10

    We propose a genetic local search algorithm (GLSA) for the optimization design of diffractive optical elements (DOE's). This hybrid algorithm incorporates advantages of both genetic algorithm (GA) and local search techniques. It appears better able to locate the global minimum compared with a canonical GA. Sample cases investigated here include the optimization design of binary-phase Dammann gratings, continuous surface-relief grating array generators, and a uniform top-hat focal plane intensity profile generator. Two GLSA's whose incorporated local search techniques are the hill-climbing method and the simulated annealing algorithm are investigated. Numerical experimental results demonstrate that the proposed algorithm is highly efficient and robust. DOE's that have high diffraction efficiency and excellent uniformity can be achieved by use of the algorithm we propose.

  7. Reward Draws the Eye, Uncertainty Holds the Eye: Associative Learning Modulates Distractor Interference in Visual Search

    Directory of Open Access Journals (Sweden)

    Stephan Koenig

    2017-07-01

    Full Text Available Stimuli in our sensory environment differ with respect to their physical salience but moreover may acquire motivational salience by association with reward. If we repeatedly observed that reward is available in the context of a particular cue but absent in the context of another cue the former typically attracts more attention than the latter. However, we also may encounter cues uncorrelated with reward. A cue with 50% reward contingency may induce an average reward expectancy but at the same time induces high reward uncertainty. In the current experiment we examined how both values, reward expectancy and uncertainty, affected overt attention. Two different colors were established as predictive cues for low reward and high reward respectively. A third color was followed by high reward on 50% of the trials and thus induced uncertainty. Colors then were introduced as distractors during search for a shape target, and we examined the relative potential of the color distractors to capture and hold the first fixation. We observed that capture frequency corresponded to reward expectancy while capture duration corresponded to uncertainty. The results may suggest that within trial reward expectancy is represented at an earlier time window than uncertainty.

  8. The role of trauma-related distractors on neural systems for working memory and emotion processing in posttraumatic stress disorder.

    Science.gov (United States)

    Morey, Rajendra A; Dolcos, Florin; Petty, Christopher M; Cooper, Debra A; Hayes, Jasmeet Pannu; LaBar, Kevin S; McCarthy, Gregory

    2009-05-01

    The relevance of emotional stimuli to threat and survival confers a privileged role in their processing. In PTSD, the ability of trauma-related information to divert attention is especially pronounced. Information unrelated to the trauma may also be highly distracting when it shares perceptual features with trauma material. Our goal was to study how trauma-related environmental cues modulate working memory networks in PTSD. We examined neural activity in participants performing a visual working memory task while distracted by task-irrelevant trauma and non-trauma material. Recent post-9/11 veterans were divided into a PTSD group (n=22) and a trauma-exposed control group (n=20) based on the Davidson trauma scale. Using fMRI, we measured hemodynamic change in response to emotional (trauma-related) and neutral distraction presented during the active maintenance period of a delayed-response working memory task. The goal was to examine differences in functional networks associated with working memory (dorsolateral prefrontal cortex and lateral parietal cortex) and emotion processing (amygdala, ventrolateral prefrontal cortex, and fusiform gyrus). The PTSD group showed markedly different neural activity compared to the trauma-exposed control group in response to task-irrelevant visual distractors. Enhanced activity in ventral emotion processing regions was associated with trauma distractors in the PTSD group, whereas activity in brain regions associated with working memory and attention regions was disrupted by distractor stimuli independent of trauma content. Neural evidence for the impact of distraction on working memory is consistent with PTSD symptoms of hypervigilance and general distractibility during goal-directed cognitive processing.

  9. Determination of toxic and essential element concentrations in foodstuffs from local market

    International Nuclear Information System (INIS)

    Surtipanti; Suwirma; Yumiarti; June, M.; Syaifudin, S.

    1989-01-01

    Determination of toxic and essential elements concentrations in foodstuffs from local market in Jakarta. Concentration of toxic essential elements, such as, As, Hg, Cr, Pb, Cu, and Zn, in rice, corn bean, small green peas, wheat, vegetables, fruits, tea and coffee, have been determined. As, Hg, Sb, Cr, Se, and Zn, were determined using neutron activation analysis, after being irradiated at TRIGA-MARK II reactor, while Pb and Cu were determined using atomic absorption spectrophotometer. The results obtained were lower than the maximum permissible concentration allowed. (author). 8 refs

  10. A locally conservative stabilized continuous Galerkin finite element method for two-phase flow in poroelastic subsurfaces

    Science.gov (United States)

    Deng, Q.; Ginting, V.; McCaskill, B.; Torsu, P.

    2017-10-01

    We study the application of a stabilized continuous Galerkin finite element method (CGFEM) in the simulation of multiphase flow in poroelastic subsurfaces. The system involves a nonlinear coupling between the fluid pressure, subsurface's deformation, and the fluid phase saturation, and as such, we represent this coupling through an iterative procedure. Spatial discretization of the poroelastic system employs the standard linear finite element in combination with a numerical diffusion term to maintain stability of the algebraic system. Furthermore, direct calculation of the normal velocities from pressure and deformation does not entail a locally conservative field. To alleviate this drawback, we propose an element based post-processing technique through which local conservation can be established. The performance of the method is validated through several examples illustrating the convergence of the method, the effectivity of the stabilization term, and the ability to achieve locally conservative normal velocities. Finally, the efficacy of the method is demonstrated through simulations of realistic multiphase flow in poroelastic subsurfaces.

  11. LMFBR operational and experimental local-fault experience, primarily with oxide fuel elements

    International Nuclear Information System (INIS)

    Warinner, D.K.

    1980-01-01

    Case-by-case reviews of selective world experience with severe local faults, particularly fuel failure and fuel degradation, are reviewed for two sodium-cooled thermal reactors, several LMFBRs, and LMFBR-fuels experiments. The review summarizes fuel-failure frequency and illustrates the results of the most damaging LMFBR local-fault experiences of the last 20 years beginning with BR-5 and including DFR, BOR-60, BR2's MFBS- and Mol-loops experiments, Fermi, KNK, Rapsodie, EBR-II, and TREAT-D2. Local-fault accommodation is demonstrated and a need to more thoroughly investigate delayed-neutron and gaseous-fission-product signals is highlighted in view of uranate formation, observed blockages, and slow fuel-element failure-propagation

  12. Brain circuitries involved in semantic interference by demands of emotional and non-emotional distractors.

    Directory of Open Access Journals (Sweden)

    Natalia Chechko

    Full Text Available BACKGROUND: Previous studies have indicated that the processes leading to the resolution of emotional and non-emotional interference conflicts are unrelated, involving separate networks. It is also known that conflict resolution itself suggests a considerable overlap of the networks. Our study is an attempt to examine how these findings may be related. METHODOLOGY/PRINCIPAL FINDINGS: We used functional magnetic resonance imaging (fMRI to study neural responses of 24 healthy subjects to emotional and non-emotional conflict paradigms involving the presentation of congruent and incongruent word-face pairs based on semantic incompatibility between targets and distractors. In the emotional task, the behavioral interference conflict was greater (compared to the non-emotional task and was paralleled by involvement of the extrastriate visual and posterodorsal medial frontal cortices. In both tasks, we also observed a common network including the dorsal anterior cingulate, the supplemental motor area, the anterior insula and the inferior prefrontal cortex, indicating that these brain structures are markers of experienced conflict. However, the emotional task involved conflict-triggered networks to a considerably higher degree. CONCLUSIONS/SIGNIFICANCE: Our findings indicate that responses to emotional and non-emotional distractors involve the same systems, which are capable of flexible adjustments based on conflict demands. The function of systems related to conflict resolution is likely to be adjusted on the basis of an evaluation process that primarily involves the extrastriate visual cortex, with target playing a significant role.

  13. Trace elements content of sudanese local snuff and its agricultural soil

    International Nuclear Information System (INIS)

    Hassan, R. E.; Eltayeb, M. A.

    2003-01-01

    Toombak is a local form of snuff widely used in Sudan. Dipping snuff is a common habit in Sudanese male subject. Many reports have related at the high incidence rate of oral cancer and other types of cancer in Sudanese subjects to this habit. trace elements such as Cu, Co, Cd, Cr, Fe, Mn, Pb, and Zn were measured using atomic absorption spectrometry in soil on which toombak is grown and toombak eaves. The average concentration (μg/g) of these elements in soil and toombak leaves were found to be 60.8 and 18.1 (Cu), 72.2 and 50.9 (Zn), 48.4 and 19.9 (Co), 398.6 and 211.7 (Mn), 17391.9 and 6410.7 (Fe), 16.1 and 5.3 (Cr), 27.7 and 7.9 (Pb), 7.2 and 4.8 (Cd), respectively. Soil to plant transfer factor was determined and found to be less than unity. The correlation coefficient between concentrations of trace elements in soils, and their soil-to-toombak transfer factors divided the elements into two groups, first group have inverse correlation while the second group is independent of their soil concentration. (Author)

  14. Local deformation method for measuring element tension in space deployable structures

    Directory of Open Access Journals (Sweden)

    Belov Sergey

    2017-01-01

    Full Text Available The article describes the local deformation method to determine the tension of cord and thin membrane elements in space deployable structure as antenna reflector. Possible measuring instrument model, analytical and numerical solutions and experimental results are presented. The boundary effects on measurement results of metallic mesh reflector surface tension are estimated. The study case depicting non-uniform reflector surface tension is considered.

  15. MAIN LAND USE PLANNING APPROACHES TO STRUCTURAL ELEMENTS LOCAL ECOLOGICAL NETWORK

    Directory of Open Access Journals (Sweden)

    TretiakV.M.

    2016-08-01

    Full Text Available In modern conditions of social development, changes in land eco-system of economic relations in Ukraine, the problem of providing conditions for the creation of sustainable land use and creation of protected areas get the status of special urgency. Ideology establishment of ecological networks became logical continuation of environmental thought in general. Considering the methodological approach to the establishment of ecological networks we can constitute, that it is an environmental frame of spatial infrastructure, land conservation and environmental areas, major part of land is the basis of the structural elements of ecological network. Designing an ecological network is made through developing regional schemes of Econet formation, regional and local schemes for establishing an ecological network areas, settlements and other areas. Land Management uses design of structural elements of the ecological network in the village council, as a rule, begins with ecological and landscape mikrozonationof the village council, held during the preparatory work for the land drafting and finishing the formation of environmentally homogeneous regions, which represents the tied system components of ecological network, environmental measures in the form of local environmental restrictions (encumbrances to use land and other natural resources. Additionally, there are some project organization and territorial measures that increase the sustainability area, such as: key, binders, buffer areas and renewable ecological network. Land management projects on the formation of structural elements of ecological network as territorial restrictions (encumbrances in land are used within the territories Councils determined the location and size of land: - Protection zones around especially valuable natural objects of cultural heritage, meteorological stations, etc. in order to protect them from adverse human impacts; - Protection zones along telecommunication lines, power

  16. Massive 3-loop ladder diagrams for quarkonic local operator matrix elements

    Energy Technology Data Exchange (ETDEWEB)

    Ablinger, Jakob; Schneider, Carsten [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation; Bluemlein, Johannes; Hasselhuhn, Alexander; Wissbrock, Fabian [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Klein, Sebastian [Technische Hochschule Aachen (Germany). Inst. fuer Theoretische Physik

    2012-06-15

    3-loop diagrams of the ladder-type, which emerge for local quarkonic twist-2 operator matrix elements, are computed directly for general values of the Mellin variable N using Appell-function representations and applying modern summation technologies provided by the package Sigma and the method of hyperlogarithms. In some of the diagrams generalized harmonic sums with {xi} element of {l_brace}1,1/2,2{r_brace} emerge beyond the usual nested harmonic sums. As the asymptotic representation of the corresponding integrals shows, the generalized sums conspire giving well behaved expressions for large values of N. These diagrams contribute to the 3-loop heavy flavor Wilson coefficients of the structure functions in deep-inelastic scattering in the region Q{sup 2} >> m{sup 2}.

  17. Massive 3-loop ladder diagrams for quarkonic local operator matrix elements

    Energy Technology Data Exchange (ETDEWEB)

    Ablinger, Jakob [Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz (Austria); Bluemlein, Johannes, E-mail: johannes.bluemlein@desy.de [Deutsches Elektronen-Synchrotron, DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Hasselhuhn, Alexander [Deutsches Elektronen-Synchrotron, DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Klein, Sebastian [Research Institut fuer Theoretische Physik E, RWTH Aachen University, D-52056 Aachen (Germany); Schneider, Carsten [Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz (Austria); Wissbrock, Fabian [Deutsches Elektronen-Synchrotron, DESY, Platanenallee 6, D-15738 Zeuthen (Germany)

    2012-11-01

    3-loop diagrams of the ladder-type, which emerge for local quarkonic twist-2 operator matrix elements, are computed directly for general values of the Mellin variable N using Appell-function representations and applying modern summation technologies provided by the package Sigma and the method of hyperlogarithms. In some of the diagrams generalized harmonic sums with {xi} Element-Of {l_brace}1,1/2,2{r_brace} emerge beyond the usual nested harmonic sums. As the asymptotic representation of the corresponding integrals shows, the generalized sums conspire giving well behaved expressions for large values of N. These diagrams contribute to the 3-loop heavy flavor Wilson coefficients of the structure functions in deep-inelastic scattering in the region Q{sup 2} Much-Greater-Than m{sup 2}.

  18. Differential Distractor Functioning as a Method for Explaining DIF: The Case of a National Admissions Test in Saudi Arabia

    Science.gov (United States)

    Tsaousis, Ioannis; Sideridis, Georgios; Al-Saawi, Fahad

    2018-01-01

    The aim of the present study was to examine Differential Distractor Functioning (DDF) as a means of improving the quality of a measure through understanding biased responses across groups. A DDF analysis could shed light on the potential sources of construct-irrelevant variance by examining whether the differential selection of incorrect choices…

  19. A locally conservative non-negative finite element formulation for anisotropic advective-diffusive-reactive systems

    Science.gov (United States)

    Mudunuru, M. K.; Shabouei, M.; Nakshatrala, K.

    2015-12-01

    Advection-diffusion-reaction (ADR) equations appear in various areas of life sciences, hydrogeological systems, and contaminant transport. Obtaining stable and accurate numerical solutions can be challenging as the underlying equations are coupled, nonlinear, and non-self-adjoint. Currently, there is neither a robust computational framework available nor a reliable commercial package known that can handle various complex situations. Herein, the objective of this poster presentation is to present a novel locally conservative non-negative finite element formulation that preserves the underlying physical and mathematical properties of a general linear transient anisotropic ADR equation. In continuous setting, governing equations for ADR systems possess various important properties. In general, all these properties are not inherited during finite difference, finite volume, and finite element discretizations. The objective of this poster presentation is two fold: First, we analyze whether the existing numerical formulations (such as SUPG and GLS) and commercial packages provide physically meaningful values for the concentration of the chemical species for various realistic benchmark problems. Furthermore, we also quantify the errors incurred in satisfying the local and global species balance for two popular chemical kinetics schemes: CDIMA (chlorine dioxide-iodine-malonic acid) and BZ (Belousov--Zhabotinsky). Based on these numerical simulations, we show that SUPG and GLS produce unphysical values for concentration of chemical species due to the violation of the non-negative constraint, contain spurious node-to-node oscillations, and have large errors in local and global species balance. Second, we proposed a novel finite element formulation to overcome the above difficulties. The proposed locally conservative non-negative computational framework based on low-order least-squares finite elements is able to preserve these underlying physical and mathematical properties

  20. Local Projection-Based Stabilized Mixed Finite Element Methods for Kirchhoff Plate Bending Problems

    Directory of Open Access Journals (Sweden)

    Xuehai Huang

    2013-01-01

    Full Text Available Based on stress-deflection variational formulation, we propose a family of local projection-based stabilized mixed finite element methods for Kirchhoff plate bending problems. According to the error equations, we obtain the error estimates of the approximation to stress tensor in energy norm. And by duality argument, error estimates of the approximation to deflection in H1-norm are achieved. Then we design an a posteriori error estimator which is closely related to the equilibrium equation, constitutive equation, and nonconformity of the finite element spaces. With the help of Zienkiewicz-Guzmán-Neilan element spaces, we prove the reliability of the a posteriori error estimator. And the efficiency of the a posteriori error estimator is proved by standard bubble function argument.

  1. LMFBR fuel-design environment for endurance testing, primarily of oxide fuel elements with local faults

    International Nuclear Information System (INIS)

    Warinner, D.K.

    1980-01-01

    The US Department of Energy LMFBR Lines-of-Assurance are briefly stated and local faults are given perspective with an historical review and definition to help define the constraints of LMFBR fuel-element designs. Local-fault-propagation (fuel-element failure-propagation and blockage propagation) perceptions are reviewed. Fuel pin designs and major LMFBR parameters affecting pin performance are summarized. The interpretation of failed-fuel data is aided by a discussion of the effects of nonprototypicalities. The fuel-pin endurance expected in the US, USSR, France, UK, Japan, and West Germany is outlined. Finally, fuel-failure detection and location by delayed-neutron and gaseous-fission-product monitors are briefly discussed to better realize the operational limits

  2. When Seeing Doesn't Matter: Assessing the After-Effects of Tactile Distractor Processing in the Blind and the Sighted

    Science.gov (United States)

    Frings, Christian; Amendt, Anna; Spence, Charles

    2011-01-01

    Negative priming (NP) refers to the finding that people's responses to probe targets previously presented as prime distractors are usually slower than to unrepeated stimuli. Intriguingly, the effect sizes of tactile NP were much larger than the effect sizes for visual NP. We analyzed whether the large tactile NP effect is just a side effect of the…

  3. Enhancement in statistical and image analysis for in situ µSXRF studies of elemental distribution and co-localization, using Dioscorea balcanica

    International Nuclear Information System (INIS)

    Dučić, Tanja; Borchert, Manuela; Savić, Aleksandar; Kalauzi, Aleksandar; Mitrović, Aleksandra; Radotić, Ksenija

    2013-01-01

    Synchrotron-radiation-based X-ray microfluorescence has been used for in situ investigation of the distribution of micronutrient and macronutrient elements in an unstained cross section of a stem of monocotyledonous liana plant Dioscorea balcanica Košanin. The elemental allocation has been quantified and the grouping/co-localization in straight and twisted stem internodes has been analysed. Synchrotron-based X-ray microfluorescence (µSXRF) is an analytical method suitable for in situ investigation of the distribution of micronutrient and macronutrient elements in several-micrometres-thick unstained biological samples, e.g. single cells and tissues. Elements are mapped and quantified at sub-p.p.m. concentrations. In this study the quantity, distribution and grouping/co-localization of various elements have been identified in straight and twisted internodes of the stems of the monocotyledonous climber D. balcanica Košanin. Three different statistical methods were employed to analyse the macro-nutrient and micronutrient distributions and co-localization. Macronutrient elements (K, P, Ca, Cl) are distributed homogeneously in both straight and twisted internodes. Micronutrient elements are mostly grouped in the vasculature and in the sclerenchyma cell layer. In addition, co-localization of micronutrient elements is much more prominent in twisted than in straight internodes. These image analyses and statistical methods provided very similar outcomes and could be applied to various types of biological samples imaged by µSXRF

  4. Global and local approaches to population analysis: Bonding patterns in superheavy element compounds

    Science.gov (United States)

    Oleynichenko, Alexander; Zaitsevskii, Andréi; Romanov, Stepan; Skripnikov, Leonid V.; Titov, Anatoly V.

    2018-03-01

    Relativistic effective atomic configurations of superheavy elements Cn, Nh and Fl and their lighter homologues (Hg, Tl and Pb) in their simple compounds with fluorine and oxygen are determined using the analysis of local properties of molecular Kohn-Sham density matrices in the vicinity of heavy nuclei. The difference in populations of atomic spinors with the same orbital angular momentum and different total angular momenta is demonstrated to be essential for understanding the peculiarities of chemical bonding in superheavy element compounds. The results are fully compatible with those obtained by the relativistic iterative version of conventional projection analysis of global density matrices.

  5. Obtaining local reciprocal lattice vectors from finite-element analysis.

    Science.gov (United States)

    Sutter, John P; Connolley, Thomas; Hill, Tim P; Huang, Houcheng; Sharp, Doug W; Drakopoulos, Michael

    2008-11-01

    Finite-element analysis is frequently used by engineers at synchrotron beamlines to calculate the elastic deformation of a single crystal undergoing mechanical bending or thermal load. ANSYS Workbench software is widely used for such simulations. However, although ANSYS Workbench software provides useful information on the displacements, strains and stresses within the crystal, it does not yield the local reciprocal lattice vectors that would be required for X-ray diffraction calculations. To bridge this gap, a method based on the shape functions and interpolation procedures of the software itself has been developed. An application to the double-crystal bent Laue monochromator being designed for the I12 (JEEP) wiggler beamline at the Diamond Light Source is presented.

  6. Atom-scale depth localization of biologically important chemical elements in molecular layers.

    Science.gov (United States)

    Schneck, Emanuel; Scoppola, Ernesto; Drnec, Jakub; Mocuta, Cristian; Felici, Roberto; Novikov, Dmitri; Fragneto, Giovanna; Daillant, Jean

    2016-08-23

    In nature, biomolecules are often organized as functional thin layers in interfacial architectures, the most prominent examples being biological membranes. Biomolecular layers play also important roles in context with biotechnological surfaces, for instance, when they are the result of adsorption processes. For the understanding of many biological or biotechnologically relevant phenomena, detailed structural insight into the involved biomolecular layers is required. Here, we use standing-wave X-ray fluorescence (SWXF) to localize chemical elements in solid-supported lipid and protein layers with near-Ångstrom precision. The technique complements traditional specular reflectometry experiments that merely yield the layers' global density profiles. While earlier work mostly focused on relatively heavy elements, typically metal ions, we show that it is also possible to determine the position of the comparatively light elements S and P, which are found in the most abundant classes of biomolecules and are therefore particularly important. With that, we overcome the need of artificial heavy atom labels, the main obstacle to a broader application of high-resolution SWXF in the fields of biology and soft matter. This work may thus constitute the basis for the label-free, element-specific structural investigation of complex biomolecular layers and biological surfaces.

  7. Localized spin-wave modes in a triangular magnetic element studied by micro-focused Brillouin light scattering

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, S.; Kwon, J.-H. [School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of); Grünberg, P. [Grünberg Center for Magnetic Nanomaterials, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of); Cho, B.K., E-mail: chobk@gist.ac.kr [School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of)

    2017-09-01

    Highlights: • Direct evidence of localized mode in a triangular nano-magnet using μ-BLS. • Localized regions are identified by the internal field distribution. • The spatially resolved measurement was performed to obtain 2-D intensity map. • Spin modes in same positions can be distinguish comparing with simulated spectrum. • Localized modes were identified by comparing with the simulated spatial profiles. - Abstract: Localized spin-wave modes, which were thermally excited at a specific position in a triangular magnetic element, were investigated using micro-focused Brillouin light scattering in two saturated states, the buckle and Y-states, with an applied magnetic field of 0.24 T parallel and perpendicular to the basal edge, respectively. The measured frequency spectrum at a specific beam spot position, rather than an integrated spectrum, was analyzed by comparing it with the simulation data at a precisely selected position within the beam spot area. The analyzed results were used to plot a two-dimensional intensity map and simulation spatial profile to verify the validity of the analysis. From the analysis process, two localized spin-wave modes in a triangular magnetic element were successfully identified near the apex region in the buckle state and near the basal edge region in the Y-state.

  8. Strain Localization during Equal-Channel Angular Pressing Analyzed by Finite Element Simulations

    Directory of Open Access Journals (Sweden)

    Tobias Daniel Horn

    2018-01-01

    Full Text Available Equal-Channel Angular Pressing (ECAP is a method used to introduce severe plastic deformation into a metallic billet without changing its geometry. In special cases, strain localization occurs and a pattern consisting of regions with high and low deformation (so-called shear and matrix bands can emerge. This paper studies this phenomenon numerically adopting two-dimensional finite element simulations of one ECAP pass. The mechanical behavior of aluminum is modeled using phenomenological plasticity theory with isotropic or kinematic hardening. The effects of the two different strain hardening types are investigated numerically by systematic parameter studies: while isotropic hardening only causes minor fluctuations in the plastic strain fields, a material with high initial hardening rate and sufficient strain hardening capacity can exhibit pronounced localized deformation after ECAP. The corresponding finite element simulation results show a regular pattern of shear and matrix bands. This result is confirmed experimentally by ECAP-processing of AA6060 material in a severely cold worked condition, where microstructural analysis also reveals the formation of shear and matrix bands. Excellent agreement is found between the experimental and numerical results in terms of shear and matrix band width and length scale. The simulations provide additional insights regarding the evolution of the strain and stress states in shear and matrix bands.

  9. Numerical Modeling of Local Penetration of Chloride-Containing Medium into Construction Elements Made of Reinforced Concrete

    Science.gov (United States)

    Ovchinnikov, I. I.; Snezhkina, O. V.; Ovchinnikov, I. G.

    2017-11-01

    The task of modeling the kinetics of chloride-containing medium penetration into construction elements out of reinforced concrete that have partially damaged anti-corrosion protective coatings is being discussed. As a result, chlorides penetrate the construction element via local surface areas which leads to irregularities between chloride dispersion volumes. The kinetics of chloride penetration is described by the equation of diffusion to solve which the CONDUCT software complex by professor S. Patankar was used. The methodology used to solve the diffusional equation is described. The results of the evaluation of concentration field in the axial section of a cylindrical construction element, which was centrally reinforced, are given. The chloride diffusion was symmetrical to the axis, the medium was applied through the central ring area equal to one third of the side surface area while the rest of the surface was isolated. It was shown that the methodology of evaluation and its algorithm allow one to evaluate the concentration field of chlorides in reinforced concrete structural elements under local or asymmetrical action of the chloride - containing medium. The example given illustrates that after a certain time interval critical the concentration of chlorides develops even in protected areas which are located far from the initial damaged area. This means that the corrosion destruction of reinforced elements develops not only in the immediate damage area, but also further away from it.

  10. LMFBR operational and experimental in-core local-fault experience, primarily with oxide fuel elements

    International Nuclear Information System (INIS)

    Warinner, D.K.

    Case-by-case reviews of selective world experience with severe local faults, particularly fuel failure and fuel degradation, are reviewed for two sodium-cooled thermal reactors, several LMFBRs, and LMFBR-fuels experiments. The review summarizes fuel-failure frequency and illustrates the results of the most damaging LMFBR local-fault experiences of the last 20 years beginning with BR-5 and including DFR, BOR-60, BR2's MFBS-and Mol-loops experiments, Fermi, KNK, Rapsodie, EBR-II, and TREAT-D2. Local-fault accommodation is demonstrated and a need to more thoroughly investigate delayed-neutron and gaseous-fission-product signals is highlighted in view of uranate formation, observed blockages, and slow fuel-element failure-propagation

  11. When Distractors and To-Be-Remembered Items Compete for the Control of Action: A New Perspective on Serial Memory for Spatial Information

    Science.gov (United States)

    Guerard, Katherine; Tremblay, Sebastien

    2011-01-01

    In serial memory for spatial information, performance is impaired when distractors are interpolated between to-be-remembered (TBR) stimuli (Tremblay, Nicholls, Parmentier, & Jones, 2005). The so-called sandwich effect, combined with the use of eye tracking, served as a tool for examining the role of the oculomotor system in serial memory for…

  12. Solution of free-boundary problems using finite-element/Newton methods and locally refined grids - Application to analysis of solidification microstructure

    Science.gov (United States)

    Tsiveriotis, K.; Brown, R. A.

    1993-01-01

    A new method is presented for the solution of free-boundary problems using Lagrangian finite element approximations defined on locally refined grids. The formulation allows for direct transition from coarse to fine grids without introducing non-conforming basis functions. The calculation of elemental stiffness matrices and residual vectors are unaffected by changes in the refinement level, which are accounted for in the loading of elemental data to the global stiffness matrix and residual vector. This technique for local mesh refinement is combined with recently developed mapping methods and Newton's method to form an efficient algorithm for the solution of free-boundary problems, as demonstrated here by sample calculations of cellular interfacial microstructure during directional solidification of a binary alloy.

  13. Selective Attention to Visual Stimuli Using Auditory Distractors Is Altered in Alpha-9 Nicotinic Receptor Subunit Knock-Out Mice.

    Science.gov (United States)

    Terreros, Gonzalo; Jorratt, Pascal; Aedo, Cristian; Elgoyhen, Ana Belén; Delano, Paul H

    2016-07-06

    During selective attention, subjects voluntarily focus their cognitive resources on a specific stimulus while ignoring others. Top-down filtering of peripheral sensory responses by higher structures of the brain has been proposed as one of the mechanisms responsible for selective attention. A prerequisite to accomplish top-down modulation of the activity of peripheral structures is the presence of corticofugal pathways. The mammalian auditory efferent system is a unique neural network that originates in the auditory cortex and projects to the cochlear receptor through the olivocochlear bundle, and it has been proposed to function as a top-down filter of peripheral auditory responses during attention to cross-modal stimuli. However, to date, there is no conclusive evidence of the involvement of olivocochlear neurons in selective attention paradigms. Here, we trained wild-type and α-9 nicotinic receptor subunit knock-out (KO) mice, which lack cholinergic transmission between medial olivocochlear neurons and outer hair cells, in a two-choice visual discrimination task and studied the behavioral consequences of adding different types of auditory distractors. In addition, we evaluated the effects of contralateral noise on auditory nerve responses as a measure of the individual strength of the olivocochlear reflex. We demonstrate that KO mice have a reduced olivocochlear reflex strength and perform poorly in a visual selective attention paradigm. These results confirm that an intact medial olivocochlear transmission aids in ignoring auditory distraction during selective attention to visual stimuli. The auditory efferent system is a neural network that originates in the auditory cortex and projects to the cochlear receptor through the olivocochlear system. It has been proposed to function as a top-down filter of peripheral auditory responses during attention to cross-modal stimuli. However, to date, there is no conclusive evidence of the involvement of olivocochlear

  14. Implied Spatial Meaning and Visuospatial Bias: Conceptual Processing Influences Processing of Visual Targets and Distractors.

    Directory of Open Access Journals (Sweden)

    Davood G Gozli

    Full Text Available Concepts with implicit spatial meaning (e.g., "hat", "boots" can bias visual attention in space. This result is typically found in experiments with a single visual target per trial, which can appear at one of two locations (e.g., above vs. below. Furthermore, the interaction is typically found in the form of speeded responses to targets appearing at the compatible location (e.g., faster responses to a target above fixation, after reading "hat". It has been argued that these concept-space interactions could also result from experimentally-induced associations between the binary set of locations and the conceptual categories with upward and downward meaning. Thus, rather than reflecting a conceptually driven spatial bias, the effect could reflect a benefit for compatible cue-target sequences that occurs only after target onset. We addressed these concerns by going beyond a binary set of locations and employing a search display consisting of four items (above, below, left, and right. Within each search trial, before performing a visual search task, participants performed a conceptual task involving concepts with implicit upward or downward meaning. The search display, in addition to including a target, could also include a salient distractor. Assuming a conceptually driven visual bias, we expected to observe, first, a benefit for target processing at the compatible location and, second, an increase in the cost of the salient distractor. The findings confirmed both predictions, suggesting that concepts do indeed generate a spatial bias. Finally, results from a control experiment, without the conceptual task, suggest the presence of an axis-specific effect, in addition to the location-specific effect, suggesting that concepts might cause both location-specific and axis-specific spatial bias. Taken together, our findings provide additional support for the involvement of spatial processing in conceptual understanding.

  15. Fuel-element temperature nonstationary distribution caused by local pulsations of the factor of heat transfer to a coolant

    International Nuclear Information System (INIS)

    Pupko, V.Ya.

    1978-01-01

    The equation of nonstationary heat transfer caused by the appearance of a local pulse jump in the factor of heat transfer to a coolant is solved analytically for a cylindrical fuel element. The problem solution is generalized to a case of the periodically pulsating factor of heat transfer according to its value in an arbitrary point of the fuel element surface

  16. Planing of land use of structural elements of ecological network at local level

    OpenAIRE

    Tretiak V.; Hun'ko L.

    2016-01-01

    and Management projecting of structural elements of land use of the ecological network on the territory of the village council begins with ecological and landscape micro zoning of the territory of village council, held during the preparatory work for the drafting of land and are finished by the formation of environmentally homogeneous regions, to which the system components of ecological network are tied, as well as environmental measures in the form of local environmental restrictions (encum...

  17. Comparative analysis of elements and models of implementation in local-level spatial plans in Serbia

    Directory of Open Access Journals (Sweden)

    Stefanović Nebojša

    2017-01-01

    Full Text Available Implementation of local-level spatial plans is of paramount importance to the development of the local community. This paper aims to demonstrate the importance of and offer further directions for research into the implementation of spatial plans by presenting the results of a study on models of implementation. The paper describes the basic theoretical postulates of a model for implementing spatial plans. A comparative analysis of the application of elements and models of implementation of plans in practice was conducted based on the spatial plans for the local municipalities of Arilje, Lazarevac and Sremska Mitrovica. The analysis includes four models of implementation: the strategy and policy of spatial development; spatial protection; the implementation of planning solutions of a technical nature; and the implementation of rules of use, arrangement and construction of spaces. The main results of the analysis are presented and used to give recommendations for improving the elements and models of implementation. Final deliberations show that models of implementation are generally used in practice and combined in spatial plans. Based on the analysis of how models of implementation are applied in practice, a general conclusion concerning the complex character of the local level of planning is presented and elaborated. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR 36035: Spatial, Environmental, Energy and Social Aspects of Developing Settlements and Climate Change - Mutual Impacts and Grant no. III 47014: The Role and Implementation of the National Spatial Plan and Regional Development Documents in Renewal of Strategic Research, Thinking and Governance in Serbia

  18. All Small Nuclear RNAs (snRNAs) of the [U4/U6.U5] Tri-snRNP Localize to Nucleoli; Identification of the Nucleolar Localization Element of U6 snRNA

    Science.gov (United States)

    Gerbi, Susan A.; Lange, Thilo Sascha

    2002-01-01

    Previously, we showed that spliceosomal U6 small nuclear RNA (snRNA) transiently passes through the nucleolus. Herein, we report that all individual snRNAs of the [U4/U6.U5] tri-snRNP localize to nucleoli, demonstrated by fluorescence microscopy of nucleolar preparations after injection of fluorescein-labeled snRNA into Xenopus oocyte nuclei. Nucleolar localization of U6 is independent from [U4/U6] snRNP formation since sites of direct interaction of U6 snRNA with U4 snRNA are not nucleolar localization elements. Among all regions in U6, the only one required for nucleolar localization is its 3′ end, which associates with the La protein and subsequently during maturation of U6 is bound by Lsm proteins. This 3′-nucleolar localization element of U6 is both essential and sufficient for nucleolar localization and also required for localization to Cajal bodies. Conversion of the 3′ hydroxyl of U6 snRNA to a 3′ phosphate prevents association with the La protein but does not affect U6 localization to nucleoli or Cajal bodies. PMID:12221120

  19. A local level set method based on a finite element method for unstructured meshes

    International Nuclear Information System (INIS)

    Ngo, Long Cu; Choi, Hyoung Gwon

    2016-01-01

    A local level set method for unstructured meshes has been implemented by using a finite element method. A least-square weighted residual method was employed for implicit discretization to solve the level set advection equation. By contrast, a direct re-initialization method, which is directly applicable to the local level set method for unstructured meshes, was adopted to re-correct the level set function to become a signed distance function after advection. The proposed algorithm was constructed such that the advection and direct reinitialization steps were conducted only for nodes inside the narrow band around the interface. Therefore, in the advection step, the Gauss–Seidel method was used to update the level set function using a node-by-node solution method. Some benchmark problems were solved by using the present local level set method. Numerical results have shown that the proposed algorithm is accurate and efficient in terms of computational time

  20. A local level set method based on a finite element method for unstructured meshes

    Energy Technology Data Exchange (ETDEWEB)

    Ngo, Long Cu; Choi, Hyoung Gwon [School of Mechanical Engineering, Seoul National University of Science and Technology, Seoul (Korea, Republic of)

    2016-12-15

    A local level set method for unstructured meshes has been implemented by using a finite element method. A least-square weighted residual method was employed for implicit discretization to solve the level set advection equation. By contrast, a direct re-initialization method, which is directly applicable to the local level set method for unstructured meshes, was adopted to re-correct the level set function to become a signed distance function after advection. The proposed algorithm was constructed such that the advection and direct reinitialization steps were conducted only for nodes inside the narrow band around the interface. Therefore, in the advection step, the Gauss–Seidel method was used to update the level set function using a node-by-node solution method. Some benchmark problems were solved by using the present local level set method. Numerical results have shown that the proposed algorithm is accurate and efficient in terms of computational time.

  1. Massive 3-loop ladder diagrams for quarkonic local operator matrix elements

    International Nuclear Information System (INIS)

    Ablinger, Jakob; Blümlein, Johannes; Hasselhuhn, Alexander; Klein, Sebastian; Schneider, Carsten; Wißbrock, Fabian

    2012-01-01

    3-loop diagrams of the ladder-type, which emerge for local quarkonic twist-2 operator matrix elements, are computed directly for general values of the Mellin variable N using Appell-function representations and applying modern summation technologies provided by the package Sigma and the method of hyperlogarithms. In some of the diagrams generalized harmonic sums with ξ∈{1,1/2,2} emerge beyond the usual nested harmonic sums. As the asymptotic representation of the corresponding integrals shows, the generalized sums conspire giving well behaved expressions for large values of N. These diagrams contribute to the 3-loop heavy flavor Wilson coefficients of the structure functions in deep-inelastic scattering in the region Q 2 ≫m 2 .

  2. Memoria de trabajo en niños escolarizados: efecto de intervalos de presentación y distractores en la prueba computarizada Memonum

    Directory of Open Access Journals (Sweden)

    Carlos Arturo Conde Cotes

    2013-06-01

    Full Text Available La presente investigación evaluó la memoria de trabajo visual a través de la prueba computarizada Memonum en niños escolarizados. Se evaluaron los efectos de tres tiempos de exposición (1, 4 y 8 segundos y de la presentación de un distractor sobre el desempeño mnemónico en la prueba Memonum en 72 niños pertenecientes a un colegio del área metropolitana de Bucaramanga, Colombia, con edades entre 8 y 11 años de los grados tercero, cuarto y quinto de primaria. Se encontró una diferencia significativa entre los tiempos de exposición en las variables número de aciertos y aciertos acumulados, demostrandoun mejor desempeño mnemónico en los participantes que presentaron la prueba en el tiempo de 8 segundos en comparación con los niños pertenecientes al grupo de 1 segundo; además, la presencia del distractor demostró una diferencia significativa en los aciertos y aciertos acumulados, considerándose como un estímulo generador de interferencia que perturba la capacidad de almacenamiento de la memoria de trabajo en niños. Adicionalmente, se halló una diferencia significativa en cuanto al uso de la estrategia de repetición mental, indicando que los participantes de los grupos de 4 y 8 segundos leasignaron mayor puntaje que los niños del grupo de 1 segundo. Un amplio tiempo de exposición de estímulos en la prueba Memonum aumenta la capacidad de retención; asimismo, el empleo de un distractor afecta en los participantes la capacidad de almacenamiento y esta, a suvez, aumenta de acuerdo a la progresión escolar, debidoal uso de las estrategias mnemónicas que los niños utilizan para garantizar el recuerdo de las series numéricas.

  3. Text localization using standard deviation analysis of structure elements and support vector machines

    Directory of Open Access Journals (Sweden)

    Zagoris Konstantinos

    2011-01-01

    Full Text Available Abstract A text localization technique is required to successfully exploit document images such as technical articles and letters. The proposed method detects and extracts text areas from document images. Initially a connected components analysis technique detects blocks of foreground objects. Then, a descriptor that consists of a set of suitable document structure elements is extracted from the blocks. This is achieved by incorporating an algorithm called Standard Deviation Analysis of Structure Elements (SDASE which maximizes the separability between the blocks. Another feature of the SDASE is that its length adapts according to the requirements of the application. Finally, the descriptor of each block is used as input to a trained support vector machines that classify the block as text or not. The proposed technique is also capable of adjusting to the text structure of the documents. Experimental results on benchmarking databases demonstrate the effectiveness of the proposed method.

  4. Attentional Capture by Salient Distractors during Visual Search Is Determined by Temporal Task Demands

    DEFF Research Database (Denmark)

    Kiss, Monika; Grubert, Anna; Petersen, Anders

    2012-01-01

    The question whether attentional capture by salient but taskirrelevant visual stimuli is triggered in a bottom–up fashion or depends on top–down task settings is still unresolved. Strong support for bottom–up capture was obtained in the additional singleton task, in which search arrays were visible...... until response onset. Equally strong evidence for top–down control of attentional capture was obtained in spatial cueing experiments in which display durations were very brief. To demonstrate the critical role of temporal task demands on salience-driven attentional capture, we measured ERP indicators...... component that was followed by a late Pd component, suggesting that they triggered attentional capture, which was later replaced by location-specific inhibition. When search arrays were visible for only 200 msec, the distractor-elicited N2pc was eliminated and was replaced by a Pd component in the same time...

  5. Dietary intake of trace elements and magnesium by local population around tailings pond at Jaduguda

    International Nuclear Information System (INIS)

    Jha, V.N.; Sethy, N.K.; Sahoo, S.K.; Shukla, A.K.; Tripathi, R.M.; Puranik, V.D.

    2007-01-01

    Dietary intake of trace elements by local population residing within 0.5 Kms from tailings pond was assessed. Intake of Zn, Cu and Fe through processed whole meal vegetarian was estimated to be 28%, 45% and 18% of the Indian national average intake. Intake of manganese is more than the national average. This can be attributed to its elevated concentration in abiotic components of the ecosystem and easy bioavailability in the concerned environment. Intake of trace elements through non-veg meal is Zn: 0.94%, Cu: 0.75%, Mn: 1.83%, Fe: 0.72% whereas, intake through total vegetable is Zn: 1.85%, Cu: 1.8%, Mn: 4.5%, Fe 1% of the national average. (author)

  6. Effects of adult attachment and emotional distractors on brain mechanisms of cognitive control.

    Science.gov (United States)

    Warren, Stacie L; Bost, Kelly K; Roisman, Glenn I; Silton, Rebecca Levin; Spielberg, Jeffrey M; Engels, Anna S; Choi, Eunsil; Sutton, Bradley P; Miller, Gregory A; Heller, Wendy

    2010-12-01

    Using data from 34 participants who completed an emotion-word Stroop task during functional magnetic resonance imaging, we examined the effects of adult attachment on neural activity associated with top-down cognitive control in the presence of emotional distractors. Individuals with lower levels of secure-base-script knowledge--reflected in an adult's inability to generate narratives in which attachment-related threats are recognized, competent help is provided, and the problem is resolved--demonstrated more activity in prefrontal cortical regions associated with emotion regulation (e.g., right orbitofrontal cortex) and with top-down cognitive control (left dorsolateral prefrontal cortex, anterior cingulate cortex, and superior frontal gyrus). Less efficient performance and related increases in brain activity suggest that insecure attachment involves a vulnerability to distraction by attachment-relevant emotional information and that greater cognitive control is required to attend to task-relevant, nonemotional information. These results contribute to the understanding of mechanisms through which attachment-related experiences may influence developmental adaptation.

  7. Retranslocation and localization of nutrient elements in various organs of moso bamboo (Phyllostachys pubescens)

    Energy Technology Data Exchange (ETDEWEB)

    Umemura, Mitsutoshi, E-mail: mitsutoshi.ume@gmail.com; Takenaka, Chisato, E-mail: chisato@agr.nagoya-u.ac.jp

    2014-09-15

    Moso bamboo (Phyllostachys pubescens) is one of the major giant bamboo species growing in Japan, and the invasion of mismanaged bamboo populations into contiguous forests has been a serious problem. To understand expansion mechanisms of the bamboo, it is important to obtain some first insights into the plant's rapid growth from the viewpoints of the nutrient dynamics in bamboo organs. We have investigated seasonal changes in the concentrations of several nutrient elements in leaves of the plants from three P. pubescens forests and the distributions of those elements in both mature (culms, branches, leaves, roots, and rhizomes) and growing organs (shoots and rhizomes). Among all elements analyzed, boron (B) concentrations in leaves showed a specific seasonal variation that was synchronous across all study sites. Boron was detected at high concentrations in the younger parts of growing rhizomes and shoots, and in mature leaves. These results indicate that P. pubescens could actively utilize B for vegetative reproduction by the retranslocation and the local accumulation behaving as mobile B. Silicon (Si) was found in high concentrations in surface parts of culms and in the mature sheaths of growing rhizomes and shoots following those in mature leaves. P. pubescens, a plant known to accumulate Si, accumulated only low levels of Ca and B in the leaves, indicating that it is possible to utilize more Si for cell wall enhancement than Ca or B. In both mature culms and rhizomes, zinc (Zn) was found at much higher concentrations in the nodes with meristematic tissue than those in internodes, indicating that Zn might play a role in promoting culm and rhizome elongation. We suggest that specific and local utilization of B, Si, and Zn in P. pubescens might support the vegetative reproduction and rapid growth. - Highlights: • The bamboo efficiently utilizes boron by the retranslocation and local accumulation. • Zinc found in nodes at high concentrations may support

  8. Retranslocation and localization of nutrient elements in various organs of moso bamboo (Phyllostachys pubescens)

    International Nuclear Information System (INIS)

    Umemura, Mitsutoshi; Takenaka, Chisato

    2014-01-01

    Moso bamboo (Phyllostachys pubescens) is one of the major giant bamboo species growing in Japan, and the invasion of mismanaged bamboo populations into contiguous forests has been a serious problem. To understand expansion mechanisms of the bamboo, it is important to obtain some first insights into the plant's rapid growth from the viewpoints of the nutrient dynamics in bamboo organs. We have investigated seasonal changes in the concentrations of several nutrient elements in leaves of the plants from three P. pubescens forests and the distributions of those elements in both mature (culms, branches, leaves, roots, and rhizomes) and growing organs (shoots and rhizomes). Among all elements analyzed, boron (B) concentrations in leaves showed a specific seasonal variation that was synchronous across all study sites. Boron was detected at high concentrations in the younger parts of growing rhizomes and shoots, and in mature leaves. These results indicate that P. pubescens could actively utilize B for vegetative reproduction by the retranslocation and the local accumulation behaving as mobile B. Silicon (Si) was found in high concentrations in surface parts of culms and in the mature sheaths of growing rhizomes and shoots following those in mature leaves. P. pubescens, a plant known to accumulate Si, accumulated only low levels of Ca and B in the leaves, indicating that it is possible to utilize more Si for cell wall enhancement than Ca or B. In both mature culms and rhizomes, zinc (Zn) was found at much higher concentrations in the nodes with meristematic tissue than those in internodes, indicating that Zn might play a role in promoting culm and rhizome elongation. We suggest that specific and local utilization of B, Si, and Zn in P. pubescens might support the vegetative reproduction and rapid growth. - Highlights: • The bamboo efficiently utilizes boron by the retranslocation and local accumulation. • Zinc found in nodes at high concentrations may support

  9. Finite Element Analysis of the Amontons-Coulomb's Model using Local and Global Friction Tests

    International Nuclear Information System (INIS)

    Oliveira, M. C.; Menezes, L. F.; Ramalho, A.; Alves, J. L.

    2011-01-01

    In spite of the abundant number of experimental friction tests that have been reported, the contact with friction modeling persists to be one of the factors that determine the effectiveness of sheet metal forming simulation. This difficulty can be understood due to the nature of the friction phenomena, which comprises the interaction of different factors connected to both sheet and tools' surfaces. Although in finite element numerical simulations friction models are commonly applied at the local level, they normally rely on parameters identified based on global experimental tests results. The aim of this study is to analyze the applicability of the Amontons-Coulomb's friction coefficient identified using complementary tests: (i) load-scanning, at the local level and (ii) draw-bead, at the global level; to the numerical simulation of sheet metal forming processes.

  10. Monitoring and source apportionment of trace elements in PM2.5: Implications for local air quality management.

    Science.gov (United States)

    Li, Yueyan; Chang, Miao; Ding, Shanshan; Wang, Shiwen; Ni, Dun; Hu, Hongtao

    2017-07-01

    Fine particulate matter (PM 2.5 ) samples were collected simultaneously every hour in Beijing between April 2014 and April 2015 at five sites. Thirteen trace elements (TEs) in PM 2.5 were analyzed by online X-ray fluorescence (XRF). The annual average PM 2.5 concentrations ranged from 76.8 to 102.7 μg m -3 . TEs accounted for 5.9%-8.7% of the total PM 2.5 mass with Cl, S, K, and Si as the most dominant elements. Spearman correlation coefficients of PM 2.5 or TE concentrations between the background site and other sites showed that PM 2.5 and some element loadings were affected by regional and local sources, whereas Cr, Si, and Ni were attributed to substantial local emissions. Temporal variations of TEs in PM 2.5 were significant and provided information on source profiles. The PM 2.5 concentrations were highest in autumn and lowest in summer. Mn and Cr showed similar variation. Fe, Ca, Si, and Ti tended to show higher concentrations in spring, whereas concentrations of S peaked in summer. Concentrations of Cl, K, Pb, Zn, Cu, and Ni peaked in winter. PM 2.5 and TE median concentrations were higher on Saturdays than on weekdays. The diurnal pattern of PM 2.5 and TE median concentrations yielded similar bimodal patterns. Five dominant sources of PM 2.5 mass were identified via positive matrix factorization (PMF). These sources included the regional and local secondary aerosols, traffic, coal burning, soil dust, and metal processing. Air quality management strategies, including regional environmental coordination and collaboration, reduction in secondary aerosol precursors, restrictive vehicle emission standards, promotion of public transport, and adoption of clean energy, should be strictly implemented. High time-resolution measurements of TEs provided detailed source profiles, which can greatly improve precision in interpreting source apportionment calculations; the PMF analysis of online XRF data is a powerful tool for local air quality management. Copyright

  11. Reward acts on the pFC to enhance distractor resistance of working memory representations.

    Science.gov (United States)

    Fallon, Sean James; Cools, Roshan

    2014-12-01

    Working memory and reward processing are often thought to be separate, unrelated processes. However, most daily activities involve integrating these two types of information, and the two processes rarely, if ever, occur in isolation. Here, we show that working memory and reward interact in a task-dependent manner and that this task-dependent interaction involves modulation of the pFC by the ventral striatum. Specifically, BOLD signal during gains relative to losses in the ventral striatum and pFC was associated not only with enhanced distractor resistance but also with impairment in the ability to update working memory representations. Furthermore, the effect of reward on working memory was accompanied by differential coupling between the ventral striatum and ignore-related regions in the pFC. Together, these data demonstrate that reward-related signals modulate the balance between cognitive stability and cognitive flexibility by altering functional coupling between the ventral striatum and the pFC.

  12. Synthesis and crystal chemistry of transuranium element chalcogenides. Contribution to the study of the 5f electron localization

    International Nuclear Information System (INIS)

    Damien, Daniel.

    1976-09-01

    The synthesis and crystal chemistry of Np, Pu, Am and Cm transuranium element chalcogenides are described. From plutonium, transuranium element chalcogenides exhibit the same crystal structure as their rare-earth homologues. The variations of the lattice constants of these compounds in terms of the atomic number are characterized by the lack of the 5f contraction and are interpreted by a localization of the 5f electrons depending upon the considered transuranium element, the nature of the ligand and the crystal structure. To compare the degree of magnitude of the 5f electron delocalization in various compounds, a delocalization scale is proposed based on a comparison between the molar volumes of actinide and isostructural lanthanide compounds. This scale provides a delocalization coefficient for each compound under study. Examination of these coefficients shows that the 5f electrons, in series of actinide compounds, become localized when going from neptunium to curium and that the delocalization process does not only depend upon overlaps between 5f-6d orbitals of neighbouring actinide atoms; the delocalization coefficients show the existence of a secondary delocalization effect due to overlaps between the p anion and f actinide orbitals which are more important for the Vb anion group (N, P, As, Sb) than for the Vib one (S,Se,Te) [fr

  13. Local and regional anthropogenic influence on PM 2.5 elements in Hong Kong

    Science.gov (United States)

    Hagler, G. S. W.; Bergin, M. H.; Salmon, L. G.; Yu, J. Z.; Wan, E. C. H.; Zheng, M.; Zeng, L. M.; Kiang, C. S.; Zhang, Y. H.; Schauer, J. J.

    Hong Kong's persistent unhealthy level of fine particulate matter is a current public health challenge, complicated by the city being located in the rapidly industrializing Pearl River Delta Region of China. While the sources of the region's fine particulate matter (PM 2.5) are still not well understood, this study provides new source information through ground measurements and statistical analysis of 24 elements associated with particulate matter collected on filters. Field measurements took place over 4 months (October 2002, December 2002, March 2003, and June 2003) at seven sites throughout the Pearl River Delta, with three sites located in Hong Kong and four sites in the neighboring province, Guangdong. The 4-month average element concentrations show significant variation throughout the region, with higher levels of nearly every species seen among the northern Guangdong sites in comparison to Hong Kong. The high correlation (Pearson r>0.8) and similar magnitudes of 11 species (Al, Si, S, K, Ca, Mn, Fe, Zn, Br, Rb, and Pb) at three contrasting sites in Hong Kong indicate that sources external to Hong Kong dominate the regional levels of these elements. Further correlative analysis compared Hong Kong against potential source areas in Guangdong Province (Shenzhen, Zhongshan, and Guangzhou). Moderate correlation of sulfur for all pairings of Hong Kong sites with three Guangdong sites in developed areas (average Pearson r of 0.52-0.94) supports the importance of long-distance transport impacting the region as a whole, although local sources also clearly impact observed concentrations. Varying correlative characteristics for zinc when Hong Kong sites are paired with Shenzhen (average r=0.86), Guangzhou (average r=-0.65) and Zhongshan (average r=0.45) points to a source area located south of Guangzhou and locally impacting Zhongshan. The concentration distribution and correlative characteristics of bromide point to sources located within the Pearl River Delta, but the

  14. Broadband Acoustic Transmission Enhancement through a Structured Stiff Plate with Locally Resonant Elements

    International Nuclear Information System (INIS)

    Li Yong; Liang Bin; Zou Xin-Ye; Cheng Jian-Chun

    2012-01-01

    Broadband acoustic transmission enhancement (ATE) is realized for a periodically structured stiff plate without any opening that is conventionally thought to be only capable of supporting narrowband ATE, by introducing locally resonant (LR) elements. This exotic phenomenon is interpreted by analyzing the vibration pattern of the structure-induced LR modes, and is well modeled by a simple 'spring-mass' system which reveals the contribution of the LR effect to the important broadband performance. Our findings should help to better understand the physical mechanism of ATE and may have potential impact on ultrasonic applications such as broadband acoustic filters or compact acoustic devices in subwavelength scale

  15. Copper localization, elemental content, and thallus colour in the copper hyperaccumulator lichen Lecanora sierra from California

    Science.gov (United States)

    Purvis, O.W.; Bennett, J.P.; Spratt, J.

    2011-01-01

    An unusual dark blue-green lichen, Lecanora sierrae, was discovered over 30 years ago by Czehura near copper mines in the Lights Creek District, Plumas County, Northern California. Using atomic absorption spectroscopy, Czehura found that dark green lichen samples from Warren Canyon contained 4% Cu in ash and suggested that its colour was due to copper accumulation in the cortex. The present study addressed the hypothesis that the green colour in similar material we sampled from Warren Canyon in 2008, is caused by copper localization in the thallus. Optical microscopy and electron microprobe analysis of specimens of L. sierrae confirmed that copper localization took place in the cortex. Elemental analyses of L. sierrae and three other species from the same localities showed high enrichments of copper and selenium, suggesting that copper selenates or selenites might occur in these lichens and be responsible for the unusual colour.

  16. Copper localization, elemental content, and thallus colour in the copper hyperaccumulator lichen Lecanora sierrae from California

    Science.gov (United States)

    Purvis, O.W.; Bennett, J.P.; Spratt, J.

    2011-01-01

    An unusual dark blue-green lichen, Lecanora sierrae, was discovered over 30 years ago by Czehura near copper mines in the Lights Creek District, Plumas County, Northern California. Using atomic absorption spectroscopy, Czehura found that dark green lichen samples from Warren Canyon contained 4% Cu in ash and suggested that its colour was due to copper accumulation in the cortex. The present study addressed the hypothesis that the green colour in similar material we sampled from Warren Canyon in 2008, is caused by copper localization in the thallus. Optical microscopy and electron microprobe analysis of specimens of L. sierrae confirmed that copper localization took place in the cortex. Elemental analyses of L. sierrae and three other species from the same localities showed high enrichments of copper and selenium, suggesting that copper selenates or selenites might occur in these lichens and be responsible for the unusual colour. Copyright ?? 2011 British Lichen Society.

  17. Local network assessment

    Science.gov (United States)

    Glen, D. V.

    1985-04-01

    Local networks, related standards activities of the Institute of Electrical and Electronics Engineers the American National Standards Institute and other elements are presented. These elements include: (1) technology choices such as topology, transmission media, and access protocols; (2) descriptions of standards for the 802 local area networks (LAN's); high speed local networks (HSLN's) and military specification local networks; and (3) intra- and internetworking using bridges and gateways with protocols Interconnection (OSI) reference model. The convergence of LAN/PBX technology is also described.

  18. The Impact of a Nickel-Copper Smelter on Concentrations of Toxic Elements in Local Wild Food from the Norwegian, Finnish, and Russian Border Regions.

    Science.gov (United States)

    Hansen, Martine D; Nøst, Therese H; Heimstad, Eldbjørg S; Evenset, Anita; Dudarev, Alexey A; Rautio, Arja; Myllynen, Päivi; Dushkina, Eugenia V; Jagodic, Marta; Christensen, Guttorm N; Anda, Erik E; Brustad, Magritt; Sandanger, Torkjel M

    2017-06-28

    Toxic elements emitted from the Pechenganickel complex on the Kola Peninsula have caused concern about potential effects on local wild food in the border regions between Norway, Finland and Russia. The aim of this study was to assess Ni, Cu, Co, As, Pb, Cd, and Hg concentrations in local wild foods from these border regions. During 2013-2014, we collected samples of different berry, mushroom, fish, and game species from sites at varying distances from the Ni-Cu smelter in all three border regions. Our results indicate that the Ni-Cu smelter is the main source of Ni, Co, and As in local wild foods, whereas the sources of Pb and Cd are more complex. We observed no consistent trends for Cu, one of the main toxic elements emitted by the Ni-Cu smelter; nor did we find any trend for Hg in wild food. Concentrations of all investigated toxic elements were highest in mushrooms, except for Hg, which was highest in fish. EU maximum levels of Pb, Cd, and Hg were exceeded in some samples, but most had levels considered safe for human consumption. No international thresholds exist for the other elements under study.

  19. Elements of Terrorism Preparedness in Local Police Agencies, 2003-2007: Impact of Vulnerability, Organizational Characteristics, and Contagion in the Post-9/11 Era

    Science.gov (United States)

    Roberts, Aki; Roberts, John M., Jr.; Liedka, Raymond V.

    2012-01-01

    Different elements of local police agencies' terrorism preparedness may be associated with different organizational/environmental variables. We use 2003-2007 data (showing considerable adoption and desistance of practices) on medium-to-large-sized local agencies to examine relationships between contingency (vulnerability, organizational…

  20. Global-Local Finite Element Analysis of Bonded Single-Lap Joints

    Science.gov (United States)

    Kilic, Bahattin; Madenci, Erdogan; Ambur, Damodar R.

    2004-01-01

    Adhesively bonded lap joints involve dissimilar material junctions and sharp changes in geometry, possibly leading to premature failure. Although the finite element method is well suited to model the bonded lap joints, traditional finite elements are incapable of correctly resolving the stress state at junctions of dissimilar materials because of the unbounded nature of the stresses. In order to facilitate the use of bonded lap joints in future structures, this study presents a finite element technique utilizing a global (special) element coupled with traditional elements. The global element includes the singular behavior at the junction of dissimilar materials with or without traction-free surfaces.

  1. A search asymmetry reversed by figure-ground assignment.

    Science.gov (United States)

    Humphreys, G W; Müller, H

    2000-05-01

    We report evidence demonstrating that a search asymmetry favoring concave over convex targets can be reversed by altering the figure-ground assignment of edges in shapes. Visual search for a concave target among convex distractors is faster than search for a convex target among concave distractors (a search asymmetry). By using shapes with ambiguous local figure-ground relations, we demonstrated that search can be efficient (with search slopes around 10 ms/item) or inefficient (with search slopes around 30-40 ms/item) with the same stimuli, depending on whether edges are assigned to concave or convex "figures." This assignment process can operate in a top-down manner, according to the task set. The results suggest that attention is allocated to spatial regions following the computation of figure-ground relations in parallel across the elements present. This computation can also be modulated by top-down processes.

  2. Multiscale finite element methods for high-contrast problems using local spectral basis functions

    KAUST Repository

    Efendiev, Yalchin

    2011-02-01

    In this paper we study multiscale finite element methods (MsFEMs) using spectral multiscale basis functions that are designed for high-contrast problems. Multiscale basis functions are constructed using eigenvectors of a carefully selected local spectral problem. This local spectral problem strongly depends on the choice of initial partition of unity functions. The resulting space enriches the initial multiscale space using eigenvectors of local spectral problem. The eigenvectors corresponding to small, asymptotically vanishing, eigenvalues detect important features of the solutions that are not captured by initial multiscale basis functions. Multiscale basis functions are constructed such that they span these eigenfunctions that correspond to small, asymptotically vanishing, eigenvalues. We present a convergence study that shows that the convergence rate (in energy norm) is proportional to (H/Λ*)1/2, where Λ* is proportional to the minimum of the eigenvalues that the corresponding eigenvectors are not included in the coarse space. Thus, we would like to reach to a larger eigenvalue with a smaller coarse space. This is accomplished with a careful choice of initial multiscale basis functions and the setup of the eigenvalue problems. Numerical results are presented to back-up our theoretical results and to show higher accuracy of MsFEMs with spectral multiscale basis functions. We also present a hierarchical construction of the eigenvectors that provides CPU savings. © 2010.

  3. Examining Auditing as an Essential Element of Financial Management and Good Governance in Local Government

    Directory of Open Access Journals (Sweden)

    Sindisile Maclean

    2014-06-01

    Full Text Available The purpose of the article is to address issues of auditing in the context of financial management as a contribution to good governance. Generally, not all local governments have effective and operational audit units and committees. As a result, auditing is not used as an essential element of good governance and this leads to bad audit outcomes like disclaimers and adverse opinions. The bad audit outcomes in local government have motivated the researcher to conduct the study on auditing. There are internal factors within the municipalities as well as external factors that are of interest and directed the researcher to have desire and commitment to make a contribution in this particular field of research. The key issues, amongst others, are principles of financial management, financial strategy, auditing functions such as forensic auditing, fraud auditing, forensic accounting and detection of fraud, including accounting systems and auditor’s role. This article will also attempt to reinforce existing theories and add value to local government financial discourse and good governance.

  4. Atomic adsorption on pristine graphene along the Periodic Table of Elements - From PBE to non-local functionals

    Science.gov (United States)

    Pašti, Igor A.; Jovanović, Aleksandar; Dobrota, Ana S.; Mentus, Slavko V.; Johansson, Börje; Skorodumova, Natalia V.

    2018-04-01

    The understanding of atomic adsorption on graphene is of high importance for many advanced technologies. Here we present a complete database of the atomic adsorption energies for the elements of the Periodic Table up to the atomic number 86 (excluding lanthanides) on pristine graphene. The energies have been calculated using the projector augmented wave (PAW) method with PBE, long-range dispersion interaction corrected PBE (PBE+D2, PBE+D3) as well as non-local vdW-DF2 approach. The inclusion of dispersion interactions leads to an exothermic adsorption for all the investigated elements. Dispersion interactions are found to be of particular importance for the adsorption of low atomic weight earth alkaline metals, coinage and s-metals (11th and 12th groups), high atomic weight p-elements and noble gases. We discuss the observed adsorption trends along the groups and rows of the Periodic Table as well some computational aspects of modelling atomic adsorption on graphene.

  5. Evaluation of a finite-element reciprocity method for epileptic EEG source localization: Accuracy, computational complexity and noise robustness

    DEFF Research Database (Denmark)

    Shirvany, Yazdan; Rubæk, Tonny; Edelvik, Fredrik

    2013-01-01

    The aim of this paper is to evaluate the performance of an EEG source localization method that combines a finite element method (FEM) and the reciprocity theorem.The reciprocity method is applied to solve the forward problem in a four-layer spherical head model for a large number of test dipoles...... noise and electrode misplacement.The results show approximately 3% relative error between numerically calculated potentials done by the reciprocity theorem and the analytical solutions. When adding EEG noise with SNR between 5 and 10, the mean localization error is approximately 4.3 mm. For the case...... with 10 mm electrode misplacement the localization error is 4.8 mm. The reciprocity EEG source localization speeds up the solution of the inverse problem with more than three orders of magnitude compared to the state-of-the-art methods.The reciprocity method has high accuracy for modeling the dipole...

  6. Use of a Multivector Mandibular Distractor for Treatment of Pediatric Proximal Interphalangeal Joint Pilon Fractures: A Case-Based Review.

    Science.gov (United States)

    Pedreira, Rachel; Cho, Brian H; Geer, Angela; DeJesus, Ramon A

    2018-04-01

    The difficulties in surgical treatment of pilon fractures of the finger include fragment reconstitution and posthealing stiffness. In adults, external fixation with traction and early active range of motion (AROM)/passive range of motion (PROM) during healing is considered necessary for avoiding joint stiffness and attaining realignment. The authors present a unique approach to pediatric pilon fractures that uses open reduction and multivector external fixation with delayed AROM/PROM. Initial immobilization and significant traction allowed for joint realignment and prevented noncompliance with staged distraction. The authors believe this immobilization leads to a superior outcome because, unlike adults, children tend to avoid stiffness and a larger distraction force allowed for sufficient joint realignment to regain range of motion (ROM). A right-handed 13-year-old boy sustained a right ring finger fracture and presented 12 days later. Radiographs revealed a comminuted Salter-Harris 4 fracture of the middle phalanx. The patient underwent open reduction and placement of multivector external fixation using a pediatric mandibular distractor/fixator. Significant traction was applied to distract the finger to length. Hardware was removed 6 weeks postoperatively and AROM was initiated after splinting. The patient started PROM 8 weeks postoperatively. Strengthening was initiated 2 weeks later. ROM improved and rehabilitation was continued. The patient exhibited nearly equal grip strength 12 weeks postoperatively. At 14 months follow-up, radiographs showed complete healing and joint realignment. There was no deformity or pain and finger length was restored. Management of pediatric pilon fractures is rarely described and presents unique considerations. Early-stage traction and immobilization using a multivector mandibular fixator/distractor is suitable in a child because noncompliance is avoided and there is a decreased risk for stiffness. Combining early immobilization

  7. Finite element calculations illustrating a method of model reduction for the dynamics of structures with localized nonlinearities.

    Energy Technology Data Exchange (ETDEWEB)

    Griffith, Daniel Todd; Segalman, Daniel Joseph

    2006-10-01

    A technique published in SAND Report 2006-1789 ''Model Reduction of Systems with Localized Nonlinearities'' is illustrated in two problems of finite element structural dynamics. That technique, called here the Method of Locally Discontinuous Basis Vectors (LDBV), was devised to address the peculiar difficulties of model reduction of systems having spatially localized nonlinearities. It's illustration here is on two problems of different geometric and dynamic complexity, but each containing localized interface nonlinearities represented by constitutive models for bolted joint behavior. As illustrated on simple problems in the earlier SAND report, the LDBV Method not only affords reduction in size of the nonlinear systems of equations that must be solved, but it also facilitates the use of much larger time steps on problems of joint macro-slip than would be possible otherwise. These benefits are more dramatic for the larger problems illustrated here. The work of both the original SAND report and this one were funded by the LDRD program at Sandia National Laboratories.

  8. Real-space local polynomial basis for solid-state electronic-structure calculations: A finite-element approach

    International Nuclear Information System (INIS)

    Pask, J.E.; Klein, B.M.; Fong, C.Y.; Sterne, P.A.

    1999-01-01

    We present an approach to solid-state electronic-structure calculations based on the finite-element method. In this method, the basis functions are strictly local, piecewise polynomials. Because the basis is composed of polynomials, the method is completely general and its convergence can be controlled systematically. Because the basis functions are strictly local in real space, the method allows for variable resolution in real space; produces sparse, structured matrices, enabling the effective use of iterative solution methods; and is well suited to parallel implementation. The method thus combines the significant advantages of both real-space-grid and basis-oriented approaches and so promises to be particularly well suited for large, accurate ab initio calculations. We develop the theory of our approach in detail, discuss advantages and disadvantages, and report initial results, including electronic band structures and details of the convergence of the method. copyright 1999 The American Physical Society

  9. Strength Reduction Method for Stability Analysis of Local Discontinuous Rock Mass with Iterative Method of Partitioned Finite Element and Interface Boundary Element

    Directory of Open Access Journals (Sweden)

    Tongchun Li

    2015-01-01

    element is proposed to solve the safety factor of local discontinuous rock mass. Slope system is divided into several continuous bodies and local discontinuous interface boundaries. Each block is treated as a partition of the system and contacted by discontinuous joints. The displacements of blocks are chosen as basic variables and the rigid displacements in the centroid of blocks are chosen as motion variables. The contact forces on interface boundaries and the rigid displacements to the centroid of each body are chosen as mixed variables and solved iteratively using the interface boundary equations. Flexibility matrix is formed through PFE according to the contact states of nodal pairs and spring flexibility is used to reflect the influence of weak structural plane so that nonlinear iteration is only limited to the possible contact region. With cohesion and friction coefficient reduced gradually, the states of all nodal pairs at the open or slip state for the first time are regarded as failure criterion, which can decrease the effect of subjectivity in determining safety factor. Examples are used to verify the validity of the proposed method.

  10. A Tale of Three Cell Types: Alkaloid Biosynthesis Is Localized to Sieve Elements in Opium Poppy

    Science.gov (United States)

    Bird, David A.; Franceschi, Vincent R.; Facchini, Peter J.

    2003-01-01

    Opium poppy produces a diverse array of pharmaceutical alkaloids, including the narcotic analgesics morphine and codeine. The benzylisoquinoline alkaloids of opium poppy accumulate in the cytoplasm, or latex, of specialized laticifers that accompany vascular tissues throughout the plant. However, immunofluorescence labeling using affinity-purified antibodies showed that three key enzymes, (S)-N-methylcoclaurine 3′-hydroxylase (CYP80B1), berberine bridge enzyme (BBE), and codeinone reductase (COR), involved in the biosynthesis of morphine and the related antimicrobial alkaloid sanguinarine, are restricted to the parietal region of sieve elements adjacent or proximal to laticifers. The localization of laticifers was demonstrated using antibodies specific to the major latex protein (MLP), which is characteristic of the cell type. In situ hybridization showed that CYP80B1, BBE, and COR gene transcripts were found in the companion cell paired with each sieve element, whereas MLP transcripts were restricted to laticifers. The biosynthesis and accumulation of alkaloids in opium poppy involves cell types not implicated previously in plant secondary metabolism and dramatically extends the function of sieve elements beyond the transport of solutes and information macromolecules in plants. PMID:14508000

  11. Attention induced neural response trade-off in retinotopic cortex under load.

    Science.gov (United States)

    Torralbo, Ana; Kelley, Todd A; Rees, Geraint; Lavie, Nilli

    2016-09-14

    The effects of perceptual load on visual cortex response to distractors are well established and various phenomena of 'inattentional blindness' associated with elimination of visual cortex response to unattended distractors, have been documented in tasks of high load. Here we tested an account for these effects in terms of a load-induced trade-off between target and distractor processing in retinotopic visual cortex. Participants were scanned using fMRI while performing a visual-search task and ignoring distractor checkerboards in the periphery. Retinotopic responses to target and distractors were assessed as a function of search load (comparing search set-sizes two, three and five). We found that increased load not only increased activity in frontoparietal network, but also had opposite effects on retinotopic responses to target and distractors. Target-related signals in areas V2-V3 linearly increased, while distractor response linearly decreased, with increased load. Critically, the slopes were equivalent for both load functions, thus demonstrating resource trade-off. Load effects were also found in displays with the same item number in the distractor hemisphere across different set sizes, thus ruling out local intrahemispheric interactions as the cause. Our findings provide new evidence for load theory proposals of attention resource sharing between target and distractor leading to inattentional blindness.

  12. Search asymmetry and eye movements in infants and adults.

    Science.gov (United States)

    Adler, Scott A; Gallego, Pamela

    2014-08-01

    Search asymmetry is characterized by the detection of a feature-present target amidst feature-absent distractors being efficient and unaffected by the number of distractors, whereas detection of a feature-absent target amidst feature-present distractors is typically inefficient and affected by the number of distractors. Although studies have attempted to investigate this phenomenon with infants (e.g., Adler, Inslicht, Rovee-Collier, & Gerhardstein in Infant Behavioral Development, 21, 253-272, 1998; Colombo, Mitchell, Coldren, & Atwater in Journal of Experimental Psychology: Learning, Memory and Cognition, 19, 98-109, 1990), due to methodological limitations, their findings have been unable to definitively establish the development of visual search mechanisms in infants. The present study assessed eye movements as a means to examine an asymmetry in responding to feature-present versus feature-absent targets in 3-month-olds, relative to adults. Saccade latencies to localize a target (or a distractor, as in the homogeneous conditions) were measured as infants and adults randomly viewed feature-present (R among Ps), feature-absent (P among Rs), and homogeneous (either all Rs or all Ps) arrays at set sizes of 1, 3, 5, and 8. Results indicated that neither infants' nor adults' saccade latencies to localize the target in the feature-present arrays were affected by increasing set sizes, suggesting that localization of the target was efficient. In contrast, saccade latencies to localize the target in the feature-absent arrays increased with increasing set sizes for both infants and adults, suggesting an inefficient localization. These findings indicate that infants exhibit an asymmetry consistent with that found with adults, providing support for functional bottom-up selective attention mechanisms in early infancy.

  13. Peridynamic Multiscale Finite Element Methods

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Timothy [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bond, Stephen D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Littlewood, David John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Moore, Stan Gerald [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    The problem of computing quantum-accurate design-scale solutions to mechanics problems is rich with applications and serves as the background to modern multiscale science research. The prob- lem can be broken into component problems comprised of communicating across adjacent scales, which when strung together create a pipeline for information to travel from quantum scales to design scales. Traditionally, this involves connections between a) quantum electronic structure calculations and molecular dynamics and between b) molecular dynamics and local partial differ- ential equation models at the design scale. The second step, b), is particularly challenging since the appropriate scales of molecular dynamic and local partial differential equation models do not overlap. The peridynamic model for continuum mechanics provides an advantage in this endeavor, as the basic equations of peridynamics are valid at a wide range of scales limiting from the classical partial differential equation models valid at the design scale to the scale of molecular dynamics. In this work we focus on the development of multiscale finite element methods for the peridynamic model, in an effort to create a mathematically consistent channel for microscale information to travel from the upper limits of the molecular dynamics scale to the design scale. In particular, we first develop a Nonlocal Multiscale Finite Element Method which solves the peridynamic model at multiple scales to include microscale information at the coarse-scale. We then consider a method that solves a fine-scale peridynamic model to build element-support basis functions for a coarse- scale local partial differential equation model, called the Mixed Locality Multiscale Finite Element Method. Given decades of research and development into finite element codes for the local partial differential equation models of continuum mechanics there is a strong desire to couple local and nonlocal models to leverage the speed and state of the

  14. Self-Orientation Modulates the Neural Correlates of Global and Local Processing.

    Science.gov (United States)

    Liddell, Belinda J; Das, Pritha; Battaglini, Eva; Malhi, Gin S; Felmingham, Kim L; Whitford, Thomas J; Bryant, Richard A

    2015-01-01

    Differences in self-orientation (or "self-construal") may affect how the visual environment is attended, but the neural and cultural mechanisms that drive this remain unclear. Behavioral studies have demonstrated that people from Western backgrounds with predominant individualistic values are perceptually biased towards local-level information; whereas people from non-Western backgrounds that support collectivist values are preferentially focused on contextual and global-level information. In this study, we compared two groups differing in predominant individualistic (N = 15) vs collectivistic (N = 15) self-orientation. Participants completed a global/local perceptual conflict task whilst undergoing functional Magnetic Resonance Imaging (fMRI) scanning. When participants high in individualistic values attended to the global level (ignoring the local level), greater activity was observed in the frontoparietal and cingulo-opercular networks that underpin attentional control, compared to the match (congruent) baseline. Participants high in collectivistic values activated similar attentional control networks o only when directly compared with global processing. This suggests that global interference was stronger than local interference in the conflict task in the collectivistic group. Both groups showed increased activity in dorsolateral prefrontal regions involved in resolving perceptual conflict during heightened distractor interference. The findings suggest that self-orientation may play an important role in driving attention networks to facilitate interaction with the visual environment.

  15. Efficient Linear and Non-Linear Finite Element Formulation using a New Local Enhancement of Displacement Fields for Triangular Elements

    DEFF Research Database (Denmark)

    Damkilde, Lars; Pedersen, Ronnie

    2012-01-01

    This paper describes a new triangular plane element which can be considered as a linear strain triangular element (LST) extended with incompatible displacement modes. The extended element will have a full cubic interpolation of strains and stresses. The extended LST-element is connected with other...... elements similar to the LST-element i.e. through three corner nodes and three mid-side nodes. The incompatible modes are associated with two displacement gradients at each mid-side node and displacements in the central node. The element passes the patch test and converges to the exact solution. The element...... often show a very slow convergence, and the numerical solutions will in general overestimate the bearing capacity and underestimate the displacements. The examples show that the extended incompatible element behaves much better than the corresponding compatible elements especially for coarse meshes....

  16. Finite element modeling of temperature load effects on the vibration of local modes in multi-cable structures

    Science.gov (United States)

    Treyssède, Fabien

    2018-01-01

    Understanding thermal effects on the vibration of local (cable-dominant) modes in multi-cable structures is a complicated task. The main difficulty lies in the modification by temperature change of cable tensions, which are then undetermined. This paper applies a finite element procedure to investigate the effects of thermal loads on the linear dynamics of prestressed self-weighted multi-cable structures. Provided that boundary conditions are carefully handled, the discretization of cables with nonlinear curved beam elements can properly represent the thermoelastic behavior of cables as well as their linearized dynamics. A three-step procedure that aims to replace applied pretension forces with displacement continuity conditions is used. Despite an increase in the computational cost related to beam rotational degrees of freedom, such an approach has several advantages. Nonlinear beam finite elements are usually available in commercial codes. The overall method follows a thermoelastic geometrically non-linear analysis and hereby includes the main sources of non-linearities in multi-cable structures. The effects of cable bending stiffness, which can be significant, are also naturally accounted for. The accuracy of the numerical approach is assessed thanks to an analytical model for the vibration of a single inclined cable under temperature change. Then, the effects of thermal loads are investigated for two cable bridges, highlighting how natural frequencies can be affected by temperature. Although counterintuitive, a reverse relative change of natural frequency may occur for certain local modes. This phenomenon can be explained by two distinct mechanisms, one related to the physics intrinsic to cables and the other related to the thermal deflection of the superstructure. Numerical results show that cables cannot be isolated from the rest of the structure and the importance of modeling the whole structure for a quantitative analysis of temperature effects on the

  17. CoCrMo cellular structures made by Electron Beam Melting studied by local tomography and finite element modelling

    Energy Technology Data Exchange (ETDEWEB)

    Petit, Clémence [INSA de Lyon, MATEIS CNRS UMR5510, Université de Lyon, 69621 Villeurbanne (France); Maire, Eric, E-mail: eric.maire@insa-lyon.fr [INSA de Lyon, MATEIS CNRS UMR5510, Université de Lyon, 69621 Villeurbanne (France); Meille, Sylvain; Adrien, Jérôme [INSA de Lyon, MATEIS CNRS UMR5510, Université de Lyon, 69621 Villeurbanne (France); Kurosu, Shingo; Chiba, Akihiko [Institute for Materials Research, Tohoku University, Sendai 980-0812 (Japan)

    2016-06-15

    The work focuses on the structural and mechanical characterization of Co-Cr-Mo cellular samples with cubic pore structure made by Electron Beam Melting (EBM). X-ray tomography was used to characterize the architecture of the sample. High resolution images were also obtained thanks to local tomography in which the specimen is placed close to the X-ray source. These images enabled to observe some defects due to the fabrication process: small pores in the solid phase, partially melted particles attached to the surface. Then, in situ compression tests were performed in the tomograph. The images of the deformed sample show a progressive buckling of the vertical struts leading to final fracture. The deformation initiated where the defects were present in the strut i.e. in regions with reduced local thickness. The finite element modelling confirmed the high stress concentrations of these weak points leading to the fracture of the sample. - Highlights: • CoCrMo samples fabricated by Electron Beam Melting (EBM) process are considered. • X-ray Computed Tomography is used to observe the structure of the sample. • The mechanical properties are tested thanks to an in situ test in the tomograph. • A finite element model is developed to model the mechanical behaviour.

  18. Gaze Behavior in a Natural Environment with a Task-Relevant Distractor: How the Presence of a Goalkeeper Distracts the Penalty Taker

    Directory of Open Access Journals (Sweden)

    Johannes Kurz

    2018-01-01

    Full Text Available Gaze behavior in natural scenes has been shown to be influenced not only by top–down factors such as task demands and action goals but also by bottom–up factors such as stimulus salience and scene context. Whereas gaze behavior in the context of static pictures emphasizes spatial accuracy, gazing in natural scenes seems to rely more on where to direct the gaze involving both anticipative components and an evaluation of ongoing actions. Not much is known about gaze behavior in far-aiming tasks in which multiple task-relevant targets and distractors compete for the allocation of visual attention via gaze. In the present study, we examined gaze behavior in the far-aiming task of taking a soccer penalty. This task contains a proximal target, the ball; a distal target, an empty location within the goal; and a salient distractor, the goalkeeper. Our aim was to investigate where participants direct their gaze in a natural environment with multiple potential fixation targets that differ in task relevance and salience. Results showed that the early phase of the run-up seems to be driven by both the salience of the stimulus setting and the need to perform a spatial calibration of the environment. The late run-up, in contrast, seems to be controlled by attentional demands of the task with penalty takers having habitualized a visual routine that is not disrupted by external influences (e.g., the goalkeeper. In addition, when trying to shoot a ball as accurately as possible, penalty takers directed their gaze toward the ball in order to achieve optimal foot-ball contact. These results indicate that whether gaze is driven by salience of the stimulus setting or by attentional demands depends on the phase of the actual task.

  19. Unconscious Local Motion Alters Global Image Speed

    Science.gov (United States)

    Khuu, Sieu K.; Chung, Charles Y. L.; Lord, Stephanie; Pearson, Joel

    2014-01-01

    Accurate motion perception of self and object speed is crucial for successful interaction in the world. The context in which we make such speed judgments has a profound effect on their accuracy. Misperceptions of motion speed caused by the context can have drastic consequences in real world situations, but they also reveal much about the underlying mechanisms of motion perception. Here we show that motion signals suppressed from awareness can warp simultaneous conscious speed perception. In Experiment 1, we measured global speed discrimination thresholds using an annulus of 8 local Gabor elements. We show that physically removing local elements from the array attenuated global speed discrimination. However, removing awareness of the local elements only had a small effect on speed discrimination. That is, unconscious local motion elements contributed to global conscious speed perception. In Experiment 2 we measured the global speed of the moving Gabor patterns, when half the elements moved at different speeds. We show that global speed averaging occurred regardless of whether local elements were removed from awareness, such that the speed of invisible elements continued to be averaged together with the visible elements to determine the global speed. These data suggest that contextual motion signals outside of awareness can both boost and affect our experience of motion speed, and suggest that such pooling of motion signals occurs before the conscious extraction of the surround motion speed. PMID:25503603

  20. Limitless Analytic Elements

    Science.gov (United States)

    Strack, O. D. L.

    2018-02-01

    We present equations for new limitless analytic line elements. These elements possess a virtually unlimited number of degrees of freedom. We apply these new limitless analytic elements to head-specified boundaries and to problems with inhomogeneities in hydraulic conductivity. Applications of these new analytic elements to practical problems involving head-specified boundaries require the solution of a very large number of equations. To make the new elements useful in practice, an efficient iterative scheme is required. We present an improved version of the scheme presented by Bandilla et al. (2007), based on the application of Cauchy integrals. The limitless analytic elements are useful when modeling strings of elements, rivers for example, where local conditions are difficult to model, e.g., when a well is close to a river. The solution of such problems is facilitated by increasing the order of the elements to obtain a good solution. This makes it unnecessary to resort to dividing the element in question into many smaller elements to obtain a satisfactory solution.

  1. Fundamental Dimensions and Essential Elements of Exemplary Local Extension Units

    Science.gov (United States)

    Terry, Bryan D.; Osborne, Edward

    2015-01-01

    Collaborative efforts between federal, state, and local government agencies enable local Extension units to deliver a high level of educational opportunities to local citizens. These units represent land-grant institutions by delivering non-formal education that aim to address local, regional, and state concerns. The purpose of this study was to…

  2. A robust frame element with cyclic plasticity and local joint effects

    DEFF Research Database (Denmark)

    Tidemann, Lasse; Krenk, Steen

    2018-01-01

    A robust elasto-plastic element is developed for analysis of frame structures. The element consists of a beam member with end joints with properties permitting representation of the effect of section forces in adjoining members, like axial forces. By use of the equilibrium formulation...... is developed, using a mid-step state to obtain representative information about the return path. The element is implemented in a co-rotational large-deformation computer program for frame structures. The formulation is illustrated by application to a couple of typical offshore frame structures, and comparison...... of different representations of the plastic effects illustrates the importance of a robust element with realistic representation of the cyclic plastic mechanisms....

  3. Proximate and mineral elements composition of five locally ...

    African Journals Online (AJOL)

    The proximate composition of the studied fruits were determined by the standard methods of Official Analytical Chemists, while the Mineral Elements (Ca and Mg) were analyzed using Atomic Absorption Spectrophotometry. The levels of Na+ and K+ were determined using Flame photometry and the level of P was ...

  4. Local and Regional Food Aid Procurement: An Assessment of Experience in Africa and Elements of Good Donor Practice

    OpenAIRE

    Tschirley, David L.; del Castillo, Anne Marie

    2008-01-01

    This Policy Synthesis is a summary of a longer report that discusses the procurement of food aid within the country or region where it is needed. Referred to as local and regional procurement – LRP – this practice has become a major element in multilateral food aid response over the past decade1. The paper examines the relevance and the rationale for using LRP, reviews the efficiency of World Food Program (WFP) LRP activities in Africa relative to inkind food aid and to prices in the markets ...

  5. Identifying and representing elements of local contexts in Namibia

    DEFF Research Database (Denmark)

    Rodil, Kasper; Jensen, Kasper Løvborg; Rehm, Matthias

    2013-01-01

    In an attempt to represent local context in a 3D visualisa- tionfor rural elders in Namibia we have foundmajor dierences in thecon- ceptualizationof this context between external and local partners in the co-creation process. Through the evaluation of a mobile context capture tool we found a clea...

  6. The mechanical heterogeneity of the hard callus influences local tissue strains during bone healing: a finite element study based on sheep experiments.

    Science.gov (United States)

    Vetter, A; Liu, Y; Witt, F; Manjubala, I; Sander, O; Epari, D R; Fratzl, P; Duda, G N; Weinkamer, R

    2011-02-03

    During secondary fracture healing, various tissue types including new bone are formed. The local mechanical strains play an important role in tissue proliferation and differentiation. To further our mechanobiological understanding of fracture healing, a precise assessment of local strains is mandatory. Until now, static analyses using Finite Elements (FE) have assumed homogenous material properties. With the recent quantification of both the spatial tissue patterns (Vetter et al., 2010) and the development of elastic modulus of newly formed bone during healing (Manjubala et al., 2009), it is now possible to incorporate this heterogeneity. Therefore, the aim of this study is to investigate the effect of this heterogeneity on the strain patterns at six successive healing stages. The input data of the present work stemmed from a comprehensive cross-sectional study of sheep with a tibial osteotomy (Epari et al., 2006). In our FE model, each element containing bone was described by a bulk elastic modulus, which depended on both the local area fraction and the local elastic modulus of the bone material. The obtained strains were compared with the results of hypothetical FE models assuming homogeneous material properties. The differences in the spatial distributions of the strains between the heterogeneous and homogeneous FE models were interpreted using a current mechanobiological theory (Isakson et al., 2006). This interpretation showed that considering the heterogeneity of the hard callus is most important at the intermediate stages of healing, when cartilage transforms to bone via endochondral ossification. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. Crowded visual search in children with normal vision and children with visual impairment.

    Science.gov (United States)

    Huurneman, Bianca; Cox, Ralf F A; Vlaskamp, Björn N S; Boonstra, F Nienke

    2014-03-01

    This study investigates the influence of oculomotor control, crowding, and attentional factors on visual search in children with normal vision ([NV], n=11), children with visual impairment without nystagmus ([VI-nys], n=11), and children with VI with accompanying nystagmus ([VI+nys], n=26). Exclusion criteria for children with VI were: multiple impairments and visual acuity poorer than 20/400 or better than 20/50. Three search conditions were presented: a row with homogeneous distractors, a matrix with homogeneous distractors, and a matrix with heterogeneous distractors. Element spacing was manipulated in 5 steps from 2 to 32 minutes of arc. Symbols were sized 2 times the threshold acuity to guarantee visibility for the VI groups. During simple row and matrix search with homogeneous distractors children in the VI+nys group were less accurate than children with NV at smaller spacings. Group differences were even more pronounced during matrix search with heterogeneous distractors. Search times were longer in children with VI compared to children with NV. The more extended impairments during serial search reveal greater dependence on oculomotor control during serial compared to parallel search. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. The morphing method as a flexible tool for adaptive local/non-local simulation of static fracture

    KAUST Repository

    Azdoud, Yan

    2014-04-19

    We introduce a framework that adapts local and non-local continuum models to simulate static fracture problems. Non-local models based on the peridynamic theory are promising for the simulation of fracture, as they allow discontinuities in the displacement field. However, they remain computationally expensive. As an alternative, we develop an adaptive coupling technique based on the morphing method to restrict the non-local model adaptively during the evolution of the fracture. The rest of the structure is described by local continuum mechanics. We conduct all simulations in three dimensions, using the relevant discretization scheme in each domain, i.e., the discontinuous Galerkin finite element method in the peridynamic domain and the continuous finite element method in the local continuum mechanics domain. © 2014 Springer-Verlag Berlin Heidelberg.

  9. 47 CFR 69.106 - Local switching.

    Science.gov (United States)

    2010-10-01

    ... foreign services that use local exchange switching facilities. (c) If end users of an interstate or... local exchange carriers shall establish rate elements for local switching as follows: (1) Price cap... use local exchange switching facilities for the provision of interstate or foreign services. The...

  10. Toxic trace elements in solid airborne particles and ecological risk assessment in the vicinity of local boiler house plants

    Science.gov (United States)

    Talovskaya, Anna V.; Osipova, Nina A.; Yazikov, Egor G.; Shakhova, Tatyana S.

    2017-11-01

    The article deals with assessment of anthropogenic pollution in vicinity of local boilers using the data on microelement composition of solid airborne particles deposited in snow. The anthropogenic feature of elevated accumulation levels of solid airborne particles deposited in snow in the vicinity of coal-fired boiler house is revealed in elevated concentrations (3-25 higher than background) of Cd, Sb, Mo, Pb, Sr, Ba, Ni, Mo, Zn and Co. In the vicinity oil-fired boiler house the specific elements as parts of solid airborne particles deposited in snow are V, Ni and Sb, as their content exceeds the background from 3 to 8 times. It is determined that the maximum shares in non-carcinogenic human health risk from chronic inhalation of trace elements to the human body in the vicinity of coal-fired boiler house belong to Al, Mn, Cu, Ba, Co, Pb, whereas in the vicinity of oil-fired boiler house - Al, Mn, Cu, Ni, V.

  11. Structural modeling techniques by finite element method

    International Nuclear Information System (INIS)

    Kang, Yeong Jin; Kim, Geung Hwan; Ju, Gwan Jeong

    1991-01-01

    This book includes introduction table of contents chapter 1 finite element idealization introduction summary of the finite element method equilibrium and compatibility in the finite element solution degrees of freedom symmetry and anti symmetry modeling guidelines local analysis example references chapter 2 static analysis structural geometry finite element models analysis procedure modeling guidelines references chapter 3 dynamic analysis models for dynamic analysis dynamic analysis procedures modeling guidelines and modeling guidelines.

  12. High-pressure on f-element materials

    International Nuclear Information System (INIS)

    Haire, R.G.

    1991-01-01

    540Studies of the f-elements under pressure provide important insights into their solid state chemistry and physics. From such studies of the elements and their alloys, it has been established that the normally localized f-electrons of several of these elements can become involved in bonding under pressure. The electronic behavior of f-element compounds under pressure tend to be more difficult to interpret, due to the variety and the nature of electronic orbitals that are present. The 4f-elements and some 60% of the 5f-elements have been studied under pressure. The systematic comparisons that have been established for these materials are discussed. 76 refs., 3 figs

  13. Finite element analysis of tibial fractures

    DEFF Research Database (Denmark)

    Wong, Christian Nai En; Mikkelsen, Mikkel Peter W; Hansen, Leif Berner

    2010-01-01

    Project. The data consisted of 21,219 3D elements with a cortical shell and a trabecular core. Three types of load of torsion, a direct lateral load and axial compression were applied. RESULTS: The finite element linear static analysis resulted in relevant fracture localizations and indicated relevant...

  14. Quadrature representation of finite element variational forms

    DEFF Research Database (Denmark)

    Ølgaard, Kristian Breum; Wells, Garth N.

    2012-01-01

    This chapter addresses the conventional run-time quadrature approach for the numerical integration of local element tensors associated with finite element variational forms, and in particular automated optimizations that can be performed to reduce the number of floating point operations...

  15. Passive Acoustic Source Localization at a Low Sampling Rate Based on a Five-Element Cross Microphone Array

    Directory of Open Access Journals (Sweden)

    Yue Kan

    2015-06-01

    Full Text Available Accurate acoustic source localization at a low sampling rate (less than 10 kHz is still a challenging problem for small portable systems, especially for a multitasking micro-embedded system. A modification of the generalized cross-correlation (GCC method with the up-sampling (US theory is proposed and defined as the US-GCC method, which can improve the accuracy of the time delay of arrival (TDOA and source location at a low sampling rate. In this work, through the US operation, an input signal with a certain sampling rate can be converted into another signal with a higher frequency. Furthermore, the optimal interpolation factor for the US operation is derived according to localization computation time and the standard deviation (SD of target location estimations. On the one hand, simulation results show that absolute errors of the source locations based on the US-GCC method with an interpolation factor of 15 are approximately from 1/15- to 1/12-times those based on the GCC method, when the initial same sampling rates of both methods are 8 kHz. On the other hand, a simple and small portable passive acoustic source localization platform composed of a five-element cross microphone array has been designed and set up in this paper. The experiments on the established platform, which accurately locates a three-dimensional (3D near-field target at a low sampling rate demonstrate that the proposed method is workable.

  16. Many-body-localization: strong disorder perturbative approach for the local integrals of motion

    Science.gov (United States)

    Monthus, Cécile

    2018-05-01

    For random quantum spin models, the strong disorder perturbative expansion of the local integrals of motion around the real-spin operators is revisited. The emphasis is on the links with other properties of the many-body-localized phase, in particular the memory in the dynamics of the local magnetizations and the statistics of matrix elements of local operators in the eigenstate basis. Finally, this approach is applied to analyze the many-body-localization transition in a toy model studied previously from the point of view of the entanglement entropy.

  17. Examining the effects of testwiseness in conceptual physics evaluations

    Science.gov (United States)

    DeVore, Seth; Stewart, John; Stewart, Gay

    2016-12-01

    Testwiseness is defined as the set of cognitive strategies used by a student that is intended to improve his or her score on a test regardless of the test's subject matter. Questions with elements that may be affected by testwiseness are common in physics assessments, even in those which have been extensively validated and widely used as evaluation tools in physics education research. The potential effect of several elements of testwiseness were analyzed for questions in the Force Concept Inventory (FCI) and Conceptual Survey on Electricity and Magnetism that contain distractors that are predicted to be influenced by testwiseness. This analysis was performed using data sets collected between fall 2001 and spring 2014 at one midwestern U.S. university (including over 9500 students) and between Spring 2011 and Spring 2015 at a second eastern U.S. university (including over 2500 students). Student avoidance of "none of the above" or "zero" distractors was statistically significant. The effect of the position of a distractor on its likelihood to be selected was also significant. The effects of several potential positive and negative testwiseness effects on student scores were also examined by developing two modified versions of the FCI designed to include additional elements related to testwiseness; testwiseness produced little effect post-instruction in student performance on the modified instruments.

  18. Stress recovery techniques for natural element method in 2-D solid mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jin Rae [Dept. of Naval Architecture and Ocean Engineering, Hongik University, Sejong (Korea, Republic of)

    2016-11-15

    This paper is concerned with the stress recovery for the natural element method in which the problem domain is discretized with Delaunay triangles and the structural behavior is approximated with Laplace interpolation functions. Basically, the global and local patch recovery techniques based on the L2-projection method are adopted. For the local patch recovery, the local element patches are defined by the supports of each Laplace interpolation function. For the comparison purpose, the local stress recovery is also performed using Lagrange-type basis functions that are used for 3- and 6-node triangular elements. The stresses that are recovered by the present global and local recovery techniques are compared each other and compared with the available analytic solution, in terms of their spatial distributions and the convergence rates. As well, the dependence of the recovered stress field on the type of test basis functions that are used forbnov-Galerkin (BG) and Petrov-Galerkin (PG) natural element methods is also investigated.

  19. 40 CFR 1400.6 - Enhanced local access.

    Science.gov (United States)

    2010-07-01

    ... INFORMATION Public Access § 1400.6 Enhanced local access. (a) OCA data elements. Consistent with 42 U.S.C..., may convey to the public OCA data elements orally or in writing, as long as the data elements are not... Administrator from those sections. Disseminating OCA data elements to the public in a manner consistent with...

  20. New Communication Technologies, Local Journalism and the Perception of Locality

    Directory of Open Access Journals (Sweden)

    Ali ÖZCAN

    2016-12-01

    Full Text Available Studies on local journalism as an important element of participatory democracy generally focus on the history of the local press, the financial insufficiencies of local newspapers as well as technical/ technological incompetency that occurs as a result of these factors. This research analyzes local newspapers with a new scientific point of view by focusing on the perception of locality as a mental projection of geographical constraint. Perspectives regarding the transformations on perceptions of locality as a result of the disappearance of time and space constraints due to new communication technologies, and the opportunities that new communication environments offer to local newspapers will be provided. Moreover, the ways in which local newspapers reflect on locality with their printed versions under time and space constraints will be analyzed. The research scope of the study has been limited to 15 newspapers in Konya. Structured interviews and content analysis methods were used for data collection and analysis.

  1. Finite element model for heat conduction in jointed rock masses

    International Nuclear Information System (INIS)

    Gartling, D.K.; Thomas, R.K.

    1981-01-01

    A computatonal procedure for simulating heat conduction in a fractured rock mass is proposed and illustrated in the present paper. The method makes use of a simple local model for conduction in the vicinity of a single open fracture. The distributions of fractures and fracture properties within the finite element model are based on a statistical representation of geologic field data. Fracture behavior is included in the finite element computation by locating local, discrete fractures at the element integration points

  2. A unified architecture of transcriptional regulatory elements

    DEFF Research Database (Denmark)

    Andersson, Robin; Sandelin, Albin Gustav; Danko, Charles G.

    2015-01-01

    Gene expression is precisely controlled in time and space through the integration of signals that act at gene promoters and gene-distal enhancers. Classically, promoters and enhancers are considered separate classes of regulatory elements, often distinguished by histone modifications. However...... and enhancers are considered a single class of functional element, with a unified architecture for transcription initiation. The context of interacting regulatory elements and the surrounding sequences determine local transcriptional output as well as the enhancer and promoter activities of individual elements....

  3. Global and Local Mechanical Responses for Necking of Rectangular Bars Using Updated and Total Lagrangian Finite Element Formulations

    Directory of Open Access Journals (Sweden)

    Claudio A. Careglio

    2016-01-01

    Full Text Available In simulations of forged and stamping processes using the finite element method, load displacement paths and three-dimensional stress and strains states should be well and reliably represented. The simple tension test is a suitable and economical tool to calibrate constitutive equations with finite strains and plasticity for those simulations. A complex three-dimensional stress and strain states are developed when this test is done on rectangular bars and the necking phenomenon appears. In this work, global and local numerical results of the mechanical response of rectangular bars subjected to simple tension test obtained from two different finite element formulations are compared and discussed. To this end, Updated and Total Lagrangian formulations are used in order to get the three-dimensional stress and strain states. Geometric changes together with strain and stress distributions at the cross section where necking occurs are assessed. In particular, a detailed analysis of the effective plastic strain, stress components in axial and transverse directions and pressure, and deviatoric stress components is presented. Specific numerical results are also validated with experimental measurements comparing, in turn, the performance of the two numerical approaches used in this study.

  4. Assessment of chemical element migration in soil-plant complex of Urov endemic localities of East Transbaikalia

    Science.gov (United States)

    Vadim V., Ermakov; Valentina, Danilova; Sabsbakhor, Khushvakhtova; Aklexander, Degtyarev; Sergey, Tyutikov; Victor, Berezkin; Elena, Karpova

    2014-05-01

    The comparative evaluation of the levels of biologically active chemical elements and their migration in the soil-plant complex of two Urov endemic locations in East Transbaikalia (Zolinsky and Uryumkansky) and background areas (Western Baikal region and the western area of the Trans-Baikal region) was conducted. The predominant soil-forming rocks in East Transbaikalia are weathering products of Proterozoic carbonated granitoids PR2. The surface rocks consist from granite, granodiorite, diorite quartz diorite, gabbro, norite, gabbro-norite and other. Soils - mountain and cryogenic meadow forests, mountain permafrost taiga podzolised, meadow alluvial, peaty meadow [2]. The paludification of narrow valleys and thermokarst phenomena are typical in Urov endemic localities. It reflects on the spotted of soil and differentiation of chemical composition of soils and plants. Most of the chemical elements in soils were determined by means of X-ray fluorescence, and trace elements in soils and plants - by atomic absorption spectrometry. The selenium content was measured by spectrofluorimetric method [3]. The research processed by methods of variation statistics. It was found that the soils of two locations of the Urov subregion of the biosphere were more enriched with iron, barium, calcium, uranium, thorium, phosphorus, and to a lesser extent strontium compared to background soils. The ratio of Ca: P was significantly higher in the soil of background areas, and Ca: Sr, on the contrary, in endemic soils. In assessing the migration of trace elements in soil-plant complex by means of the total content of trace elements and biological absorption coefficient found a marked accumulation by plants manganese, chromium, arsenic and weak plants accumulation of cobalt and nickel. Soil landscape is not much different in content of selenium, but its migration in plants was reduced in places of spread of Urov disease [1]. The concentrators of cadmium (leaves of different species of willow

  5. Effects of task-irrelevant grouping on visual selection in partial report

    DEFF Research Database (Denmark)

    Lunau, Rasmus; Habekost, Thomas

    2017-01-01

    and the selection criterion was luminance. This effect was accompanied by impaired selectivity in unsorted-color trials. Overall, the results suggest that the benefit of task-irrelevant color grouping of targets is contingent on the processing locus of the selection criterion....... the color of the elements in these trials. In the sorted-color condition, the color of the display elements was arranged according to the selection criterion, and in the unsorted-color condition, colors were randomly assigned. The distractor cost was inferred by subtracting performance in partial......-report trials from performance in a control condition that had no distractors in the display. Across five experiments, we manipulated trial order, selection criterion, and exposure duration, and found that attentional selectivity was improved in sorted-color trials when the exposure duration was 200 ms...

  6. Relativistic local quantum field theory for m=0 particles; Campos cuanticos locales relativos a particulas de masa no nula

    Energy Technology Data Exchange (ETDEWEB)

    Morales Villasevil, A

    1965-07-01

    A method is introduced ta deal with relativistic quantum field theory for particles with m=0. Two mappings I and J, giving rise respectively to particle and anti particle states, are defined between a test space and the physical Hilbert space. The intrinsic field operator is then defined as the minimal causal linear combinations of operators belonging to the annihilation-creation algebra associated to the germ and antigerm parts of the element. Local elements are introduced as improper test elements and local field operators are constructed in the same way as the intrinsic ones. Commutation rules are given. (Author) 17 refs.

  7. Overlapping Schwarz for Nonlinear Problems. An Element Agglomeration Nonlinear Additive Schwarz Preconditioned Newton Method for Unstructured Finite Element Problems

    Energy Technology Data Exchange (ETDEWEB)

    Cai, X C; Marcinkowski, L; Vassilevski, P S

    2005-02-10

    This paper extends previous results on nonlinear Schwarz preconditioning ([4]) to unstructured finite element elliptic problems exploiting now nonlocal (but small) subspaces. The non-local finite element subspaces are associated with subdomains obtained from a non-overlapping element partitioning of the original set of elements and are coarse outside the prescribed element subdomain. The coarsening is based on a modification of the agglomeration based AMGe method proposed in [8]. Then, the algebraic construction from [9] of the corresponding non-linear finite element subproblems is applied to generate the subspace based nonlinear preconditioner. The overall nonlinearly preconditioned problem is solved by an inexact Newton method. Numerical illustration is also provided.

  8. Visual search in Alzheimer's disease: a deficiency in processing conjunctions of features.

    Science.gov (United States)

    Tales, A; Butler, S R; Fossey, J; Gilchrist, I D; Jones, R W; Troscianko, T

    2002-01-01

    Human vision often needs to encode multiple characteristics of many elements of the visual field, for example their lightness and orientation. The paradigm of visual search allows a quantitative assessment of the function of the underlying mechanisms. It measures the ability to detect a target element among a set of distractor elements. We asked whether Alzheimer's disease (AD) patients are particularly affected in one type of search, where the target is defined by a conjunction of features (orientation and lightness) and where performance depends on some shifting of attention. Two non-conjunction control conditions were employed. The first was a pre-attentive, single-feature, "pop-out" task, detecting a vertical target among horizontal distractors. The second was a single-feature, partly attentive task in which the target element was slightly larger than the distractors-a "size" task. This was chosen to have a similar level of attentional load as the conjunction task (for the control group), but lacked the conjunction of two features. In an experiment, 15 AD patients were compared to age-matched controls. The results suggested that AD patients have a particular impairment in the conjunction task but not in the single-feature size or pre-attentive tasks. This may imply that AD particularly affects those mechanisms which compare across more than one feature type, and spares the other systems and is not therefore simply an 'attention-related' impairment. Additionally, these findings show a double dissociation with previous data on visual search in Parkinson's disease (PD), suggesting a different effect of these diseases on the visual pathway.

  9. Determination of toxic elements in foodstuffs from local market in Jakarta

    International Nuclear Information System (INIS)

    Surtipanti Sadjirun; Suwirma Safri; Endang Rosadi; Yumiarti; Yune Mellawati; Saifudin Simon; Minarni Ak

    1988-01-01

    The main foodstuffs of Indonesian people are, rice, bean, corn, wheat, vegetables, fruits, meat, fish, milk, tea, and coffee. The problem of the control of toxic elements in foodstuffs have not been carried out such as many countries, so there is no established maximum permissible concentration in the Indonesian national legislation, and that is why Indonesia participates in the Co-ordinated Research Program organized by the International Atomic Energy Agency. This program will allow exchange of experience among the participants, especially in the determination of low level toxic elements in foodstuffs using nuclear techniques. 6 refs, 9 tabs

  10. Steady State Shift Damage Localization

    DEFF Research Database (Denmark)

    Sekjær, Claus; Bull, Thomas; Markvart, Morten Kusk

    2017-01-01

    The steady state shift damage localization (S3DL) method localizes structural deterioration, manifested as either a mass or stiffness perturbation, by interrogating the damage-induced change in the steady state vibration response with damage patterns cast from a theoretical model. Damage is, thus...... the required accuracy when examining complex structures, an extensive amount of degrees of freedom (DOF) must often be utilized. Since the interrogation matrix for each damage pattern depends on the size of the system matrices constituting the FE-model, the computational time quickly becomes of first......-order importance. The present paper investigates two sub-structuring approaches, in which the idea is to employ Craig-Bampton super-elements to reduce the amount of interrogation distributions while still providing an acceptable localization resolution. The first approach operates on a strict super-element level...

  11. The informal recycling in the international and local context: theoretical Elements

    International Nuclear Information System (INIS)

    Yepes P, Dora Luz

    2002-01-01

    This article is a synthesis of the theoretical aspects related with the urban problem of the informal recycling in our means, and it is framed inside the denominated investigation project alternatives for their invigoration of the informal recycling in Medellin, which is a thesis of the grade that looks for to strengthen the informal recycling through the study of the factors associated to the labor productivity of the informal recycle. Specifically, the study will identify options of improvement of its work y points to propose alternatives to dignify the labor of these people integrally by the light of environmental precepts, technicians, normative, institutional social and of sustainability. This document describe the theoretical elements in which this investigation will be based, showing the informal recycling inside of an international context, and their situation in a national and local environment. As a result of the bibliographical revision carried out, can be said, that it glimpses a low interest in to improve the conditions of work a International level of the informal recycle, unless the strategies that it outlines the international labor organization, with regard to the strengthening of the informal economy; in Latin America, it has not been possible to go further of the official rhetoric and the pro motion of the groups environmentalists, but in the issue of the recovery policies, reuse, and the recycling of solid wastes, if there. Has been a sustained advance; at national level clear strategies to improve the informal work of the recycle are being identified, however, lacks many efforts to develop the committed actions with these strategies, in spite of the fact that has been advancing the creation of recycle organizations little by little

  12. From elements to perception: local and global processing in visual neurons.

    Science.gov (United States)

    Spillmann, L

    1999-01-01

    Gestalt psychologists in the early part of the century challenged psychophysical notions that perceptual phenomena can be understood from a punctate (atomistic) analysis of the elements present in the stimulus. Their ideas slowed later attempts to explain vision in terms of single-cell recordings from individual neurons. A rapprochement between Gestalt phenomenology and neurophysiology seemed unlikely when the first ECVP was held in Marburg, Germany, in 1978. Since that time, response properties of neurons have been discovered that invite an interpretation of visual phenomena (including illusions) in terms of neuronal processing by long-range interactions, as first proposed by Mach and Hering in the last century. This article traces a personal journey into the early days of neurophysiological vision research to illustrate the progress that has taken place from the first attempts to correlate single-cell responses with visual perceptions. Whereas initially the receptive-field properties of individual classes of cells--e.g., contrast, wavelength, orientation, motion, disparity, and spatial-frequency detectors--were used to account for relatively simple visual phenomena, nowadays complex perceptions are interpreted in terms of long-range interactions, involving many neurons. This change in paradigm from local to global processing was made possible by recent findings, in the cortex, on horizontal interactions and backward propagation (feedback loops) in addition to classical feedforward processing. These mechanisms are exemplified by studies of the tilt effect and tilt aftereffect, direction-specific motion adaptation, illusory contours, filling-in and fading, figure--ground segregation by orientation and motion contrast, and pop-out in dynamic visual-noise patterns. Major questions for future research and a discussion of their epistemological implications conclude the article.

  13. Evaluation of local trace element status and 8-Iso-prostaglandin F2α concentrations in patients with Tinea pedis.

    Science.gov (United States)

    Miraloglu, Meral; Kurutas, Ergul Belge; Ozturk, Perihan; Arican, Ozer

    2016-01-01

    Tinea pedis (TP) is an infection of the feet caused by fungi. The infectious diseases caused by dermatophytes are mainly related to the enzymes produced by these fungi. Up to the now, the local 8-iso-prostaglandin F2α (8-iso-PGF2α), concentration as oxidative stress biomarker and trace elements status have not been published in patients with TP. The aim of this study is to evaluate the relationship between oxidative stress and trace elements (Cu, Zn, Se), and to evaluate the ratios of Cu/Zn and Cu/Se in this disorder. Forty-three consecutive patients with a diagnosis of unilateral interdigital TP were enrolled in this study. The samples were obtained by scraping the skin surface. 8-iso-PGF2α concentrations in scraping samples were determined by ELISA. In addition, the levels of Se, Zn and Cu in scraping samples were determined on flame and furnace atomic absorption spectrophotometer using Zeeman background correction. Oxidative stress was confirmed by the significant elevation in 8-iso-PGF2α concentrations (p iso-PGF2α parameters, but negative correlations between Se-Cu; Se-8-iso-PGF2α parameters in lesional area. Furthermore, the ratios of Cu/Zn and Cu/Se were significantly higher on the lesional area than the non-lesional area (p iso-PGF2α and trace elements in patients with TP (p > 0.05). Our results showed that there is a possible link between oxidative stress (increased 8-iso-PGF2α concentrations) and imbalanced of trace elements status in lesional area of TP patients. The use of antifungal agents together with both Zn and Se drugs could be helpful in the both regression of disease and in shortening the duration of disease.

  14. ELEMENTS OF SAFETY IN PARAGLIDING

    OpenAIRE

    Janez Mekinc; Katarina Mušič

    2016-01-01

    Paragliding is an opportunity for tourism development, depending on what position the sport has place in the local community, the restrictions for paragliders and the safety components of the region. The paper explores the phenomenon of paragliding and safety elements in the Upper Soča region, one of ten best paragliding sites in the world (Placestoseeinyourlifetime, 2015). The purpose of the research is to analyse the safety elements, the development and the risk of paragliding.The goals of ...

  15. Discontinuous finite element solution of the radiation diffusion equation on arbitrary polygonal meshes and locally adapted quadrilateral grids

    International Nuclear Information System (INIS)

    Ragusa, Jean C.

    2015-01-01

    In this paper, we propose a piece-wise linear discontinuous (PWLD) finite element discretization of the diffusion equation for arbitrary polygonal meshes. It is based on the standard diffusion form and uses the symmetric interior penalty technique, which yields a symmetric positive definite linear system matrix. A preconditioned conjugate gradient algorithm is employed to solve the linear system. Piece-wise linear approximations also allow a straightforward implementation of local mesh adaptation by allowing unrefined cells to be interpreted as polygons with an increased number of vertices. Several test cases, taken from the literature on the discretization of the radiation diffusion equation, are presented: random, sinusoidal, Shestakov, and Z meshes are used. The last numerical example demonstrates the application of the PWLD discretization to adaptive mesh refinement

  16. The analysis of cultural architectural trends in Crisan locality

    Directory of Open Access Journals (Sweden)

    SELA Florentina

    2010-09-01

    Full Text Available The paper presents data about the identification and analyse of the traditional architectural elements in Crisan locality knowing that the tourism activity is in a continuous development. The field research (during November 2007 enabled us to develop a qualitative and quantitative analysis in terms of identification of traditional architecture elements, their conservation status, and frequency of traditional building materials use, decorative elements and specificcolors used in construction architecture. Further, based on collected data, was realized the chart - Distribution for TraditionalArchitecture Index (TAI on the distance from the center of Crisan locality, showing that in Crisan locality the houses were and are built without taking into account any rule, destroying thus traditional architecture.

  17. IMMATERIAL CULTURAL ELEMENTS PATRIMONIAZATION AND LOCAL SUSTAINABLE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Alejandro Martínez-de la Rosa

    2015-07-01

    Full Text Available Tourism and heritage studies in Mexico are mainly focused on two major areas: specific ecological areas and historical edifications. However, in the last ten years they have proposed initiatives to consider the practices related to the state and federal levels immaterial. Until today there are seven elements in the UNESCO’s Representative List of Intangible Cultural Heritage belonging to Mexico. From conceptual review of the terms used to justify the safeguarding of intangible cultural heritage in international conventions of the past fifty years, it will reflect on the relationship between processed of patrimonialization and sustainable development projects, first from a general point of view about specific problems of application in Mexico for later review.

  18. Metabolite Regulation of Nuclear Localization of Carbohydrate-response Element-binding Protein (ChREBP): ROLE OF AMP AS AN ALLOSTERIC INHIBITOR.

    Science.gov (United States)

    Sato, Shogo; Jung, Hunmin; Nakagawa, Tsutomu; Pawlosky, Robert; Takeshima, Tomomi; Lee, Wan-Ru; Sakiyama, Haruhiko; Laxman, Sunil; Wynn, R Max; Tu, Benjamin P; MacMillan, John B; De Brabander, Jef K; Veech, Richard L; Uyeda, Kosaku

    2016-05-13

    The carbohydrate-response element-binding protein (ChREBP) is a glucose-responsive transcription factor that plays an essential role in converting excess carbohydrate to fat storage in the liver. In response to glucose levels, ChREBP is regulated by nuclear/cytosol trafficking via interaction with 14-3-3 proteins, CRM-1 (exportin-1 or XPO-1), or importins. Nuclear localization of ChREBP was rapidly inhibited when incubated in branched-chain α-ketoacids, saturated and unsaturated fatty acids, or 5-aminoimidazole-4-carboxamide ribonucleotide. Here, we discovered that protein-free extracts of high fat-fed livers contained, in addition to ketone bodies, a new metabolite, identified as AMP, which specifically activates the interaction between ChREBP and 14-3-3. The crystal structure showed that AMP binds directly to the N terminus of ChREBP-α2 helix. Our results suggest that AMP inhibits the nuclear localization of ChREBP through an allosteric activation of ChREBP/14-3-3 interactions and not by activation of AMPK. AMP and ketone bodies together can therefore inhibit lipogenesis by restricting localization of ChREBP to the cytoplasm during periods of ketosis. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. Glueball Spectrum and Matrix Elements on Anisotropic Lattices

    Energy Technology Data Exchange (ETDEWEB)

    Y. Chen; A. Alexandru; S.J. Dong; T. Draper; I. Horvath; F.X. Lee; K.F. Liu; N. Mathur; C. Morningstar; M. Peardon; S. Tamhankar; B.L. Young; J.B. Zhang

    2006-01-01

    The glueball-to-vacuum matrix elements of local gluonic operators in scalar, tensor, and pseudoscalar channels are investigated numerically on several anisotropic lattices with the spatial lattice spacing ranging from 0.1fm - 0.2fm. These matrix elements are needed to predict the glueball branching ratios in J/{psi} radiative decays which will help identify the glueball states in experiments. Two types of improved local gluonic operators are constructed for a self-consistent check and the finite volume effects are studied. We find that lattice spacing dependence of our results is very weak and the continuum limits are reliably extrapolated, as a result of improvement of the lattice gauge action and local operators. We also give updated glueball masses with various quantum numbers.

  20. Some peculiarities of radioactive elements metabolism in body according to the indices of activity of blood and urine in malignant neoplasms of different localization

    International Nuclear Information System (INIS)

    Gelashvili, K.D.

    1988-01-01

    Background beta-radioactivity of blood and day urine in 115 patients (36 healthy ones and 79 suffering from malignant tumor of different localization) taking into account age was determined. It is shown that changes in background radioactivity of blood and urine both in healthy and oncologic patients are mostly presented in old age. Increase of background radioactivity of blood and urine takes place mainly not due to 40 K, but other beta-active elements - in healthy persons. Activity of blood and day urine in patients with malignant tumors decreases due to other beta-emittor, but not 40 K. Some changes in metabolic processes of beta-active elements of an organism both with the growth increase and when developing malignant tumors are established. 1 tab

  1. Maxillary Distraction Osteogenesis Using a Rigid External Distractor: Which Clinical Factors Are Related With Relapse?

    Science.gov (United States)

    Kim, Jeenam; Uhm, Ki-Il; Shin, Donghyeok; Lee, Jina; Choi, Hyungon

    2015-06-01

    Maxillary distraction osteogenesis is a reliable treatment for cleft lip and palate with midfacial retrusion. The purpose of this study was to evaluate the results of long-term follow-up in patients with cleft lip and palate after maxillary distraction osteogenesis and to find clinical factors related to relapse. From February 2002 to June 2008, 21 patients with severe class III malocclusion were treated at our hospital. We performed distraction osteotomy with a rigid external distractor device. The distraction length was more than 15 mm in all patients. Preoperative and postoperative lateral cephalometric radiographs were used for analysis. The sella-nasion-subnasale, sella-nasion-supramentale, and point-A-point-B-nasion (sella-nasion-subnasale-sella-nasion-supramentale) angles were recorded. The timelines for follow-up were preoperatively, after distraction, after consolidation, at 3 years, and once fully grown (5- to 8-year follow-ups). A comparative analysis of clinical factors was performed for the relapsing and nonrelapsing groups. Of the 21 patients, 14 had relapsed. The mean age in the relapsing group was 9.1 years (7 boys and 7 girls) with 9 patients with unilateral cleft palate and 5 c bilateral cleft palate. The mean age in the nonrelapsing group was 11.7 years (4 boys and 3 girls) with 5 patients with unilateral cleft palate and 2 patients with bilateral cleft palate. Despite greater anterior overcorrection, relapse occurred owing to scar tissue retraction and mandibular compensatory hypertrophy. The results suggest that the younger the patient, the more likely relapse will occur.

  2. Dynamic eye tracking based metrics for infant gaze patterns in the face-distractor competition paradigm.

    Directory of Open Access Journals (Sweden)

    Eero Ahtola

    Full Text Available To develop new standardized eye tracking based measures and metrics for infants' gaze dynamics in the face-distractor competition paradigm.Eye tracking data were collected from two samples of healthy 7-month-old (total n = 45, as well as one sample of 5-month-old infants (n = 22 in a paradigm with a picture of a face or a non-face pattern as a central stimulus, and a geometric shape as a lateral stimulus. The data were analyzed by using conventional measures of infants' initial disengagement from the central to the lateral stimulus (i.e., saccadic reaction time and probability and, additionally, novel measures reflecting infants gaze dynamics after the initial disengagement (i.e., cumulative allocation of attention to the central vs. peripheral stimulus.The results showed that the initial saccade away from the centrally presented stimulus is followed by a rapid re-engagement of attention with the central stimulus, leading to cumulative preference for the central stimulus over the lateral stimulus over time. This pattern tended to be stronger for salient facial expressions as compared to non-face patterns, was replicable across two independent samples of 7-month-old infants, and differentiated between 7 and 5 month-old infants.The results suggest that eye tracking based assessments of infants' cumulative preference for faces over time can be readily parameterized and standardized, and may provide valuable techniques for future studies examining normative developmental changes in preference for social signals.Standardized measures of early developing face preferences may have potential to become surrogate biomarkers of neurocognitive and social development.

  3. Artistic elements in the Rivers State Carnival: An emblemic attraction ...

    African Journals Online (AJOL)

    Amongst these groups are various masquerade groups, dance troupes, comedians and local government areas floats. These floats host sculptures and other artistic elements. This paper is a documentation and analysis of the artistic elements in the carnival of the Rivers State of Nigeria. Keywords: Arts, artistic, elements, ...

  4. Characterization and localization of metal-responsive-element-binding transcription factors from tilapia

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, Andrew Pok-Lap; Au, Candy Yee-Man; Chan, William Wai-Lun [Department of Biochemistry, Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong (Hong Kong); Chan, King Ming, E-mail: kingchan@cuhk.edu.hk [Department of Biochemistry, Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong (Hong Kong)

    2010-08-01

    Two isoforms of MTF-1, MTF-1L (long form) and MTF-1S (short form), were cloned in tilapia (Ti) and characterized in a tilapia liver cell line, Hepa-T1. The cloned tiMTF-1L has the characteristics of all of the tiMTF-1S identified so far with the zinc finger domain having six fingers, the acidic-rich, proline-rich, and serine/threonine-rich domains; however, the short form encodes for the zinc finger domain with five zinc fingers only and no other domains. The transient transfection of tiMTF-1L into human HepG2 cells showed both constitutive and zinc-induced metal-responsive-element (MRE)-driven reporter gene expression. However, the transfection of tiMTF-1S (which lacks all three transactivation domains) into a human cell line showed reduced transcriptional activities compared with an endogenous control in both basal- and Zn{sup 2+}-induced conditions. The tiMTF-1 isoforms were tagged with GFP and transfected into Hepa-T1 cells (tilapia hepatocytes). The nuclear translocation of tiMTF-1L was observed when the cells were exposed to a sufficient concentration of metals for 6 h. However, tiMTF-1S, was localized in the nucleus with or without metal treatment. Electrophoretic mobility shift assay (EMSA) confirmed that both of the isoforms were able to bind to the MRE specifically in vitro. Tissue distribution studies showed that tiMTF-1L was more abundant than tiMTF-1S in all of the tissues tested.

  5. Characterization and localization of metal-responsive-element-binding transcription factors from tilapia

    International Nuclear Information System (INIS)

    Cheung, Andrew Pok-Lap; Au, Candy Yee-Man; Chan, William Wai-Lun; Chan, King Ming

    2010-01-01

    Two isoforms of MTF-1, MTF-1L (long form) and MTF-1S (short form), were cloned in tilapia (Ti) and characterized in a tilapia liver cell line, Hepa-T1. The cloned tiMTF-1L has the characteristics of all of the tiMTF-1S identified so far with the zinc finger domain having six fingers, the acidic-rich, proline-rich, and serine/threonine-rich domains; however, the short form encodes for the zinc finger domain with five zinc fingers only and no other domains. The transient transfection of tiMTF-1L into human HepG2 cells showed both constitutive and zinc-induced metal-responsive-element (MRE)-driven reporter gene expression. However, the transfection of tiMTF-1S (which lacks all three transactivation domains) into a human cell line showed reduced transcriptional activities compared with an endogenous control in both basal- and Zn 2+ -induced conditions. The tiMTF-1 isoforms were tagged with GFP and transfected into Hepa-T1 cells (tilapia hepatocytes). The nuclear translocation of tiMTF-1L was observed when the cells were exposed to a sufficient concentration of metals for 6 h. However, tiMTF-1S, was localized in the nucleus with or without metal treatment. Electrophoretic mobility shift assay (EMSA) confirmed that both of the isoforms were able to bind to the MRE specifically in vitro. Tissue distribution studies showed that tiMTF-1L was more abundant than tiMTF-1S in all of the tissues tested.

  6. Determination of elemental distribution in green micro-algae using synchrotron radiation nano X-ray fluorescence (SR-nXRF) and electron microscopy techniques--subcellular localization and quantitative imaging of silver and cobalt uptake by Coccomyxa actinabiotis.

    Science.gov (United States)

    Leonardo, T; Farhi, E; Boisson, A-M; Vial, J; Cloetens, P; Bohic, S; Rivasseau, C

    2014-02-01

    The newly discovered unicellular micro-alga Coccomyxa actinabiotis proves to be highly radio-tolerant and strongly concentrates radionuclides, as well as large amounts of toxic metals. This study helps in the understanding of the mechanisms involved in the accumulation and detoxification of silver and cobalt. Elemental distribution inside Coccomyxa actinabiotis cells was determined using synchrotron nano X-ray fluorescence spectroscopy at the ID22 nano fluorescence imaging beamline of the European Synchrotron Radiation Facility. The high resolution and high sensitivity of this technique enabled the assessment of elemental associations and exclusions in subcellular micro-algae compartments. A quantitative treatment of the scans was implemented to yield absolute concentrations of each endogenous and exogenous element with a spatial resolution of 100 nm and compared to the macroscopic content in cobalt and silver determined using inductively coupled plasma-mass spectrometry. The nano X-ray fluorescence imaging was complemented by transmission electron microscopy coupled to X-ray microanalysis (TEM-EDS), yielding differential silver distribution in the cell wall, cytosol, nucleus, chloroplast and mitochondria with unique resolution. The analysis of endogenous elements in control cells revealed that iron had a unique distribution; zinc, potassium, manganese, molybdenum, and phosphate had their maxima co-localized in the same area; and sulfur, copper and chlorine were almost homogeneously distributed among the whole cell. The subcellular distribution and quantification of cobalt and silver in micro-alga, assessed after controlled exposure to various concentrations, revealed that exogenous metals were mainly sequestered inside the cell rather than on mucilage or the cell wall, with preferential compartmentalization. Cobalt was homogeneously distributed outside of the chloroplast. Silver was localized in the cytosol at low concentration and in the whole cell excluding the

  7. Design Transformation based on Nature and Identity Formation in the Design of Landscape Elements

    Directory of Open Access Journals (Sweden)

    Zulkifli Muslim

    2016-01-01

    Full Text Available There is a lack of initiative from the designers to integrate the environmental resources in the material and design production of local urban landscape elements that reflects human culture and lifestyle. Based on criteria and principles of symbol design and transformation process, this paper describes the symbiotic relationship between local plants (flower and designs of landscape elements. Using visual analysis, the researcher manipulated shapes and forms of local plant images in producing possible shapes and forms for a design of landscape element (lamp post. The results indicate that the design transformation is a systematic process that allows for variations in design without losing the core characteristics and identity of the basic elements of nature.

  8. Higher levels of depression are associated with reduced global bias in visual processing.

    Science.gov (United States)

    de Fockert, Jan W; Cooper, Andrew

    2014-04-01

    Negative moods have been associated with a tendency to prioritise local details in visual processing. The current study investigated the relation between depression and visual processing using the Navon task, a standard task of local and global processing. In the Navon task, global stimuli are presented that are made up of many local parts, and the participants are instructed to report the identity of either a global or a local target shape. Participants with a low self-reported level of depression showed evidence of the expected global processing bias, and were significantly faster at responding to the global, compared with the local level. By contrast, no such difference was observed in participants with high levels of depression. The reduction of the global bias associated with high levels of depression was only observed in the overall speed of responses to global (versus local) targets, and not in the level of interference produced by the global (versus local) distractors. These results are in line with recent findings of a dissociation between local/global processing bias and interference from local/global distractors, and support the claim that depression is associated with a reduction in the tendency to prioritise global-level processing.

  9. Urban soil geochemistry in Athens, Greece: The importance of local geology in controlling the distribution of potentially harmful trace elements.

    Science.gov (United States)

    Argyraki, Ariadne; Kelepertzis, Efstratios

    2014-06-01

    Understanding urban soil geochemistry is a challenging task because of the complicated layering of the urban landscape and the profound impact of large cities on the chemical dispersion of harmful trace elements. A systematic geochemical soil survey was performed across Greater Athens and Piraeus, Greece. Surface soil samples (0-10cm) were collected from 238 sampling sites on a regular 1×1km grid and were digested by a HNO3-HCl-HClO4-HF mixture. A combination of multivariate statistics and Geographical Information System approaches was applied for discriminating natural from anthropogenic sources using 4 major elements, 9 trace metals, and 2 metalloids. Based on these analyses the lack of heavy industry in Athens was demonstrated by the influence of geology on the local soil chemistry with this accounting for 49% of the variability in the major elements, as well as Cr, Ni, Co, and possibly As (median values of 102, 141, 16 and 24mg kg(-1) respectively). The contribution to soil chemistry of classical urban contaminants including Pb, Cu, Zn, Sn, Sb, and Cd (medians of 45, 39, 98, 3.6, 1.7 and 0.3mg kg(-1) respectively) was also observed; significant correlations were identified between concentrations and urbanization indicators, including vehicular traffic, urban land use, population density, and timing of urbanization. Analysis of soil heterogeneity and spatial variability of soil composition in the Greater Athens and Piraeus area provided a representation of the extent of anthropogenic modifications on natural element loadings. The concentrations of Ni, Cr, and As were relatively high compared to those in other cities around the world, and further investigation should characterize and evaluate their geochemical reactivity. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Relativistic local quantum field theory for m=0 particles

    International Nuclear Information System (INIS)

    Morales Villasevil, A.

    1965-01-01

    A method is introduced ta deal with relativistic quantum field theory for particles with m=0. Two mappings I and J, giving rise respectively to particle and anti particle states, are defined between a test space and the physical Hilbert space. The intrinsic field operator is then defined as the minimal causal linear combinations of operators belonging to the annihilation-creation algebra associated to the germ and antigerm parts of the element. Local elements are introduced as improper test elements and local field operators are constructed in the same way as the intrinsic ones. Commutation rules are given. (Author) 17 refs

  11. Dynamic Eye Tracking Based Metrics for Infant Gaze Patterns in the Face-Distractor Competition Paradigm

    Science.gov (United States)

    Ahtola, Eero; Stjerna, Susanna; Yrttiaho, Santeri; Nelson, Charles A.; Leppänen, Jukka M.; Vanhatalo, Sampsa

    2014-01-01

    Objective To develop new standardized eye tracking based measures and metrics for infants’ gaze dynamics in the face-distractor competition paradigm. Method Eye tracking data were collected from two samples of healthy 7-month-old (total n = 45), as well as one sample of 5-month-old infants (n = 22) in a paradigm with a picture of a face or a non-face pattern as a central stimulus, and a geometric shape as a lateral stimulus. The data were analyzed by using conventional measures of infants’ initial disengagement from the central to the lateral stimulus (i.e., saccadic reaction time and probability) and, additionally, novel measures reflecting infants gaze dynamics after the initial disengagement (i.e., cumulative allocation of attention to the central vs. peripheral stimulus). Results The results showed that the initial saccade away from the centrally presented stimulus is followed by a rapid re-engagement of attention with the central stimulus, leading to cumulative preference for the central stimulus over the lateral stimulus over time. This pattern tended to be stronger for salient facial expressions as compared to non-face patterns, was replicable across two independent samples of 7-month-old infants, and differentiated between 7 and 5 month-old infants. Conclusion The results suggest that eye tracking based assessments of infants’ cumulative preference for faces over time can be readily parameterized and standardized, and may provide valuable techniques for future studies examining normative developmental changes in preference for social signals. Significance Standardized measures of early developing face preferences may have potential to become surrogate biomarkers of neurocognitive and social development. PMID:24845102

  12. Newmark local time stepping on high-performance computing architectures

    KAUST Repository

    Rietmann, Max

    2016-11-25

    In multi-scale complex media, finite element meshes often require areas of local refinement, creating small elements that can dramatically reduce the global time-step for wave-propagation problems due to the CFL condition. Local time stepping (LTS) algorithms allow an explicit time-stepping scheme to adapt the time-step to the element size, allowing near-optimal time-steps everywhere in the mesh. We develop an efficient multilevel LTS-Newmark scheme and implement it in a widely used continuous finite element seismic wave-propagation package. In particular, we extend the standard LTS formulation with adaptations to continuous finite element methods that can be implemented very efficiently with very strong element-size contrasts (more than 100×). Capable of running on large CPU and GPU clusters, we present both synthetic validation examples and large scale, realistic application examples to demonstrate the performance and applicability of the method and implementation on thousands of CPU cores and hundreds of GPUs.

  13. Newmark local time stepping on high-performance computing architectures

    KAUST Repository

    Rietmann, Max; Grote, Marcus; Peter, Daniel; Schenk, Olaf

    2016-01-01

    In multi-scale complex media, finite element meshes often require areas of local refinement, creating small elements that can dramatically reduce the global time-step for wave-propagation problems due to the CFL condition. Local time stepping (LTS) algorithms allow an explicit time-stepping scheme to adapt the time-step to the element size, allowing near-optimal time-steps everywhere in the mesh. We develop an efficient multilevel LTS-Newmark scheme and implement it in a widely used continuous finite element seismic wave-propagation package. In particular, we extend the standard LTS formulation with adaptations to continuous finite element methods that can be implemented very efficiently with very strong element-size contrasts (more than 100×). Capable of running on large CPU and GPU clusters, we present both synthetic validation examples and large scale, realistic application examples to demonstrate the performance and applicability of the method and implementation on thousands of CPU cores and hundreds of GPUs.

  14. Newmark local time stepping on high-performance computing architectures

    Energy Technology Data Exchange (ETDEWEB)

    Rietmann, Max, E-mail: max.rietmann@erdw.ethz.ch [Institute for Computational Science, Università della Svizzera italiana, Lugano (Switzerland); Institute of Geophysics, ETH Zurich (Switzerland); Grote, Marcus, E-mail: marcus.grote@unibas.ch [Department of Mathematics and Computer Science, University of Basel (Switzerland); Peter, Daniel, E-mail: daniel.peter@kaust.edu.sa [Institute for Computational Science, Università della Svizzera italiana, Lugano (Switzerland); Institute of Geophysics, ETH Zurich (Switzerland); Schenk, Olaf, E-mail: olaf.schenk@usi.ch [Institute for Computational Science, Università della Svizzera italiana, Lugano (Switzerland)

    2017-04-01

    In multi-scale complex media, finite element meshes often require areas of local refinement, creating small elements that can dramatically reduce the global time-step for wave-propagation problems due to the CFL condition. Local time stepping (LTS) algorithms allow an explicit time-stepping scheme to adapt the time-step to the element size, allowing near-optimal time-steps everywhere in the mesh. We develop an efficient multilevel LTS-Newmark scheme and implement it in a widely used continuous finite element seismic wave-propagation package. In particular, we extend the standard LTS formulation with adaptations to continuous finite element methods that can be implemented very efficiently with very strong element-size contrasts (more than 100x). Capable of running on large CPU and GPU clusters, we present both synthetic validation examples and large scale, realistic application examples to demonstrate the performance and applicability of the method and implementation on thousands of CPU cores and hundreds of GPUs.

  15. Building local participation and support for ALFRED project

    International Nuclear Information System (INIS)

    Apostol, M.; Constantin, M.; Diaconu, D.

    2016-01-01

    At the beginning of 2015, a Local Dialog Group (LDG) was set-up under the FP7 ARCADIA project, as an interface between the implementer of ALFRED demonstrator (Fostering ALfred CONstruction - FALCON consortium) and local community from Mioveni town. The paper discusses the current situation and the possible evolution of the group beyond the ARCADIA project (November 2016). The possible evolution could be the transformation in a Local Committee (LC), this fact leading to the extension of LDG.s actual role, towards a larger participation in decision making process (DMP). Aspects regarding LC construction elements as local context, mission and role, legitimacy, funding and resources, organizing mode, products and outputs, the interaction with other stakeholders, are presented in the paper. In order to describe the context, some general elements concerning the Local Committees (LCs) as tools for the communities. involvement in the DMP are also introduced. (authors)

  16. Fluorescence detection of white-beam X-ray absorption anisotropy: towards element-sensitive projections of local atomic structure

    Science.gov (United States)

    Korecki, P.; Tolkiehn, M.; Dąbrowski, K. M.; Novikov, D. V.

    2011-01-01

    Projections of the atomic structure around Nb atoms in a LiNbO3 single crystal were obtained from a white-beam X-ray absorption anisotropy (XAA) pattern detected using Nb K fluorescence. This kind of anisotropy results from the interference of X-rays inside a sample and, owing to the short coherence length of a white beam, is visible only at small angles around interatomic directions. Consequently, the main features of the recorded XAA corresponded to distorted real-space projections of dense-packed atomic planes and atomic rows. A quantitative analysis of XAA was carried out using a wavelet transform and allowed well resolved projections of Nb atoms to be obtained up to distances of 10 Å. The signal of nearest O atoms was detected indirectly by a comparison with model calculations. The measurement of white-beam XAA using characteristic radiation indicates the possibility of obtaining element-sensitive projections of the local atomic structure in more complex samples. PMID:21997909

  17. Fluid-structure finite-element vibrational analysis

    Science.gov (United States)

    Feng, G. C.; Kiefling, L.

    1974-01-01

    A fluid finite element has been developed for a quasi-compressible fluid. Both kinetic and potential energy are expressed as functions of nodal displacements. Thus, the formulation is similar to that used for structural elements, with the only differences being that the fluid can possess gravitational potential, and the constitutive equations for fluid contain no shear coefficients. Using this approach, structural and fluid elements can be used interchangeably in existing efficient sparse-matrix structural computer programs such as SPAR. The theoretical development of the element formulations and the relationships of the local and global coordinates are shown. Solutions of fluid slosh, liquid compressibility, and coupled fluid-shell oscillation problems which were completed using a temporary digital computer program are shown. The frequency correlation of the solutions with classical theory is excellent.

  18. Planing of land use of structural elements of ecological network at local level

    Directory of Open Access Journals (Sweden)

    Tretiak V.

    2016-05-01

    Full Text Available and Management projecting of structural elements of land use of the ecological network on the territory of the village council begins with ecological and landscape micro zoning of the territory of village council, held during the preparatory work for the drafting of land and are finished by the formation of environmentally homogeneous regions, to which the system components of ecological network are tied, as well as environmental measures in the form of local environmental restrictions (encumbrances in land usage and other natural resources. Additionally organization and territorial measures are projected that increase the ecological sustainability of the area: key, binders, buffer areas and renewable ecological network. The regional scheme of ecological network is intended for usage while projecting of creation of new territories that fall under special protection, for defining the tasks as for changing the category of land in the land use planning documents, for development of specifications regarding the reproduction of natural systems on conservation ready lands withdrawn from agricultural use, for accounting the problems of formation the areas of ecological network in forest management and land management projects, while development of the projects of areas organization of natural - reserve fund, in the definition of wetlands of international importance, in determining the habitats of various plants and animals of various categories of protection in accordance with international conventions and national laws - regulations, in planning targeted actions in the conservation of landscape and biological diversity. The main stages of designing local ecological network are: • inventory and identification of rights for land and other natural resources, drawing created territories and objects of natural reserve fund and other areas of natural systems on the planning and cartographic materials, which are under special protection; • rationale of

  19. Concentration of stable elements in food products

    International Nuclear Information System (INIS)

    Montford, M.A.; Shank, K.E.; Hendricks, C.; Oakes, T.W.

    1980-01-01

    Food samples were taken from commercial markets and analyzed for stable element content. The concentrations of most stable elements (Ag, Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, K, La, Mg, Mn, Mo, Na, Rb, Sb, Sc, Se, Sr, Ta, Th, Ti, V, Zn, Zr) were determined using multiple-element neutron activation analysis, while the concentrations of other elements (Cd, Hg, Ni, Pb) were determined using atomic absorption. The relevance of the concentrations found are noted in relation to other literature values. An earlier study was extended to include the determination of the concentration of stable elements in home-grown products in the vicinity of the Oak Ridge National Laboratory. Comparisons between the commercial and local food-stuff values are discussed

  20. Local pharmacological effects of tungstate on the color-pattern determination of butterfly wings: a possible relationship between the eyespot and parafocal element.

    Science.gov (United States)

    Dhungel, Bidur; Otaki, Joji M

    2009-11-01

    Butterfly wing color patterns can be changed by the application of a temperature shock or pharmacological agents such as tungstate, producing a distinctive type of elemental modification called the TS (temperature shock) type. Heterochronic uncoupling between the signaling and reception steps during the color-pattern determination process has been proposed as a mechanism for TS-type changes. As an extension of this hypothesis, both the parafocal element (PFE) and the eyespot in the same wing compartment are considered to be determined by morphogenic signal(s) emitted from the same eyespot focus. However, these models need to be examined with additional experimental data. Furthermore, there is controversy as to whether the action of tungstate on wing color patterns is direct or Indirect. Using a species of nymphalid butterfly (Junonia orithya), we have devised a simple method for the local application of pharmacological agents directly on developing wings of pupae. Local tungstate application resulted in reduced eyespots and circular dislocated PFEs in the eyespot-less compartments only on the treated wing, demonstrating that tungstate directly induces color-pattern changes on wings. We further examined the eyespot-PFE relationship in normal and cold-shocked Individuals, showing that an eyespot can be superimposed on a PFE and vice versa, probably depending on the timing of their fate determination. Taken together, we propose a two-morphogen model for the normal color-pattern determination, in which the morphogenic signals for the eyespot and PFE are different from each other despite their Identical origin. This two-morphogen model is compatible with the heterochronic uncoupling model for TS-type changes.

  1. Accuracy improvement in the TDR-based localization of water leaks

    Directory of Open Access Journals (Sweden)

    Andrea Cataldo

    Full Text Available A time domain reflectometry (TDR-based system for the localization of water leaks has been recently developed by the authors. This system, which employs wire-like sensing elements to be installed along the underground pipes, has proven immune to the limitations that affect the traditional, acoustic leak-detection systems.Starting from the positive results obtained thus far, in this work, an improvement of this TDR-based system is proposed. More specifically, the possibility of employing a low-cost, water-absorbing sponge to be placed around the sensing element for enhancing the accuracy in the localization of the leak is addressed.To this purpose, laboratory experiments were carried out mimicking a water leakage condition, and two sensing elements (one embedded in a sponge and one without sponge were comparatively used to identify the position of the leak through TDR measurements. Results showed that, thanks to the water retention capability of the sponge (which maintains the leaked water more localized, the sensing element embedded in the sponge leads to a higher accuracy in the evaluation of the position of the leak. Keywords: Leak localization, TDR, Time domain reflectometry, Water leaks, Underground water pipes

  2. An effective attentional set for a specific colour does not prevent capture by infrequently presented motion distractors.

    Science.gov (United States)

    Retell, James D; Becker, Stefanie I; Remington, Roger W

    2016-01-01

    An organism's survival depends on the ability to rapidly orient attention to unanticipated events in the world. Yet, the conditions needed to elicit such involuntary capture remain in doubt. Especially puzzling are spatial cueing experiments, which have consistently shown that involuntary shifts of attention to highly salient distractors are not determined by stimulus properties, but instead are contingent on attentional control settings induced by task demands. Do we always need to be set for an event to be captured by it, or is there a class of events that draw attention involuntarily even when unconnected to task goals? Recent results suggest that a task-irrelevant event will capture attention on first presentation, suggesting that salient stimuli that violate contextual expectations might automatically capture attention. Here, we investigated the role of contextual expectation by examining whether an irrelevant motion cue that was presented only rarely (∼3-6% of trials) would capture attention when observers had an active set for a specific target colour. The motion cue had no effect when presented frequently, but when rare produced a pattern of interference consistent with attentional capture. The critical dependence on the frequency with which the irrelevant motion singleton was presented is consistent with early theories of involuntary orienting to novel stimuli. We suggest that attention will be captured by salient stimuli that violate expectations, whereas top-down goals appear to modulate capture by stimuli that broadly conform to contextual expectations.

  3. Distinguishing the elements of a full product basis set needs only projective measurements and classical communication

    International Nuclear Information System (INIS)

    Chen Pingxing; Li Chengzu

    2004-01-01

    Nonlocality without entanglement is an interesting field. A manifestation of quantum nonlocality without entanglement is the possible local indistinguishability of orthogonal product states. In this paper we analyze the character of operators to distinguish the elements of a full product basis set in a multipartite system, and show that distinguishing perfectly these product bases needs only local projective measurements and classical communication, and these measurements cannot damage each product basis. Employing these conclusions one can discuss local distinguishability of the elements of any full product basis set easily. Finally we discuss the generalization of these results to the locally distinguishability of the elements of incomplete product basis set

  4. Writing analytic element programs in Python.

    Science.gov (United States)

    Bakker, Mark; Kelson, Victor A

    2009-01-01

    The analytic element method is a mesh-free approach for modeling ground water flow at both the local and the regional scale. With the advent of the Python object-oriented programming language, it has become relatively easy to write analytic element programs. In this article, an introduction is given of the basic principles of the analytic element method and of the Python programming language. A simple, yet flexible, object-oriented design is presented for analytic element codes using multiple inheritance. New types of analytic elements may be added without the need for any changes in the existing part of the code. The presented code may be used to model flow to wells (with either a specified discharge or drawdown) and streams (with a specified head). The code may be extended by any hydrogeologist with a healthy appetite for writing computer code to solve more complicated ground water flow problems. Copyright © 2009 The Author(s). Journal Compilation © 2009 National Ground Water Association.

  5. Survey of chemical speciation of trace elements using synchrotron radiation

    International Nuclear Information System (INIS)

    Gordon, B.M.

    1985-01-01

    Information concerning the chemical state of trace elements in biological systems generally has not been available. Such information for toxic elements and metals in metalloproteins could prove extremely valuable in the elucidation of their metabolism and other biological processes. The shielding of core electrons by binding electrons affect the energy required for creating inner-shell holes. Furthermore, the molecular binding and the symmetry of the local environment of an atom affect the absorption spectrum in the neighborhood of the absorption edge. X-ray absorption near-edge structure (XANES) using synchrotron radiation excitation can be used to provide chemical speciation information for trace elements at concentrations as low as 10 ppM. The structure and position of the absorption curve in the region of an edge can yield vital data about the local structure and oxidation state of the trace element in question. Data are most easily interpreted by comparing the observed edge structure and position with those of model compounds of the element covering the entire range of possible oxidation states. Examples of such analyses are reviewed. 14 refs., 1 fig

  6. Elemental evaluation in plastic garbage bags purchased from local markets in Piracicaba, Sao Paulo state, using the EDXRF technique

    International Nuclear Information System (INIS)

    Almeida, Eduardo de; Nascimento Filho, Virgilio F.; Cavagis, Alexandre D.M.; Menegario, Amauri A.

    2011-01-01

    Plastic garbage bags have been used for packing household waste in Piracicaba city and nearby cities broadly. Many of these bags are made from recycled polymers and the presence of harmful elements is a matter of concern. In this work fourteen plastic garbage bags of different brands and colors were purchased from local markets in Piracicaba, State of Sao Paulo. For the analysis, the samples in triplicate were cut into 47 mm diameter circle and attached into acrylic holder and analyzed directly by Energy Dispersive X-Ray Fluorescence - EDXRF. The excitation was carried out using an X-ray tube Mo target and Zr filter (15 kV / 25 mA) under non-vacuum. The characteristic X-rays were detected by a semiconductor detector Si(Li), coupled to a multichannel analyzer system. The acquisition time was 500 s and the X-ray spectra were deconvulated by the AXIL software. For quantification it was used a standard set produced by the MicroMatter/USA and the absorption effect was corrected by the known chemical composition matrix technique, in which allowed the determination of K, Ca Ti, Cr, Mn, Fe, Cu, Zn, Sr by Kα lines and Pb by the line Lα simultaneously. The trueness of the method was verified by analyzing a certified reference material (NIST air particulate on filter media, SRM2783). The limits of detection (LD) for these elements were: K - 38.9; Ca - 19.4; Ti - 7.1; Cr - 3.1; Mn - 2.1; Fe - 1.5; Cu - 0.86; Zn - 0.85; Sr - 4.6 and Pb - 2.8 μg g -1 . Some elements showed minimum and/or maximum concentrations well above the LDs, as K: -1 . (author)

  7. Source localization of rhythmic ictal EEG activity

    DEFF Research Database (Denmark)

    Beniczky, Sándor; Lantz, Göran; Rosenzweig, Ivana

    2013-01-01

    Although precise identification of the seizure-onset zone is an essential element of presurgical evaluation, source localization of ictal electroencephalography (EEG) signals has received little attention. The aim of our study was to estimate the accuracy of source localization of rhythmic ictal...... EEG activity using a distributed source model....

  8. Adaptive local surface refinement based on LR NURBS and its application to contact

    Science.gov (United States)

    Zimmermann, Christopher; Sauer, Roger A.

    2017-12-01

    A novel adaptive local surface refinement technique based on Locally Refined Non-Uniform Rational B-Splines (LR NURBS) is presented. LR NURBS can model complex geometries exactly and are the rational extension of LR B-splines. The local representation of the parameter space overcomes the drawback of non-existent local refinement in standard NURBS-based isogeometric analysis. For a convenient embedding into general finite element codes, the Bézier extraction operator for LR NURBS is formulated. An automatic remeshing technique is presented that allows adaptive local refinement and coarsening of LR NURBS. In this work, LR NURBS are applied to contact computations of 3D solids and membranes. For solids, LR NURBS-enriched finite elements are used to discretize the contact surfaces with LR NURBS finite elements, while the rest of the body is discretized by linear Lagrange finite elements. For membranes, the entire surface is discretized by LR NURBS. Various numerical examples are shown, and they demonstrate the benefit of using LR NURBS: Compared to uniform refinement, LR NURBS can achieve high accuracy at lower computational cost.

  9. Histological and elemental changes in the rat brain after local irradiation with carbon ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Sentaro; Sun, Xue-Zhi; Kubota, Yoshihisa; Takai, Nobuhiko; Nojima, Kumie [National Inst. of Radiological Sciences, Chiba (Japan)

    2002-06-01

    The left cerebral hemispheres of adult Sprague-Dawley rat brains were irradiated at doses of 30, 50, or 100 Gy with charged carbon particles (290 MeV/nucleon; 5 mm spread-out Bragg peak). The spread-out Bragg peak used here successfully and satisfactorily retained its high-dose localization in the defined region. A histological examination showed that necrotic tissue damage, hemorrhage in the thalamus, and vasodilatations around the necrotic region were induced at 8 weeks after 100 Gy irradiation. The regions with tissue damage correlated well with those expected from the radiation-dose distribution, indicating an advantage of charged carbon particles for irradiating restricted brain regions. An X-ray fluorescent analysis demonstrated a decrease in the concentrations of K and P, and an increase in the concentrations of Cl, Fe, Zn in the damaged region at 8 weeks post-irradiation, though no significant changes were observed before 4 weeks of post-irradiation. This may indicate that even the very high radiation doses used here did not induce acute and immediate neuronal cell death, in contrast with ischemic brain injury where acute neuronal cell death occurred and the elemental concentrations changed within a day after the induction of ischemia. (author)

  10. Element bow profiles from new and irradiated CANDU fuel bundles

    International Nuclear Information System (INIS)

    Dennier, D.; Manzer, A.M.; Ryz, M.A.

    1996-01-01

    Improved methods of measuring element profiles on new CANDU fuel bundles were developed at the Sheridan Park Engineering Laboratory, and have now been applied in the hot cells at Whiteshell Laboratories. For the first time, the outer element profiles have been compared between new, out-reactor tested, and irradiated fuel elements. The comparison shows that irradiated element deformation is similar to that observed on elements in out-reactor tested bundles. In addition to the restraints applied to the element via appendages, the element profile appears to be strongly influenced by gravity and the end loads applied by local deformation of the endplate. Irradiation creep in the direction of gravity also tends to be a dominant factor. (author)

  11. A finite element solution method for quadrics parallel computer

    International Nuclear Information System (INIS)

    Zucchini, A.

    1996-08-01

    A distributed preconditioned conjugate gradient method for finite element analysis has been developed and implemented on a parallel SIMD Quadrics computer. The main characteristic of the method is that it does not require any actual assembling of all element equations in a global system. The physical domain of the problem is partitioned in cells of n p finite elements and each cell element is assigned to a different node of an n p -processors machine. Element stiffness matrices are stored in the data memory of the assigned processing node and the solution process is completely executed in parallel at element level. Inter-element and therefore inter-processor communications are required once per iteration to perform local sums of vector quantities between neighbouring elements. A prototype implementation has been tested on an 8-nodes Quadrics machine in a simple 2D benchmark problem

  12. Strategies for local community wind energy projects

    International Nuclear Information System (INIS)

    Jenkins, Garry

    1993-01-01

    This paper sets out some near term actions and policies which may improve the prospects for 'local group owned' wind turbines in the UK. Topics covered briefly include the advantages and disadvantages of local group owned wind projects, legal and institutional structures, the scale of projects and investment, subsidies and the NFFO, debt guarantees, public electricity supply franchises and finally the elements of a local ownership strategy for the UK. (UK)

  13. LOCAL WEATHER CLASSIFICATIONS FOR ENVIRONMENTAL APPLICATIONS

    Directory of Open Access Journals (Sweden)

    Katarzyna PIOTROWICZ

    2013-03-01

    Full Text Available Two approaches of local weather type definitions are presented and illustrated for selected stations of Poland and Hungary. The subjective classification, continuing long traditions, especially in Poland, relies on diurnal values of local weather elements. The main types are defined according to temperature with some sub-types considering relative sunshine duration, diurnal precipitation totals, relative humidity and wind speed. The classification does not make a difference between the seasons of the year, but the occurrence of the classes obviously reflects the annual cycle. Another important feature of this classification is that only a minor part of the theoretically possible combination of the various types and sub-types occurs in all stations of both countries. The objective version of the classification starts from ten possible weather element which are reduced to four according to factor analysis, based on strong correlation between the elements. This analysis yields 3 to 4 factors depending on the specific criteria of selection. The further cluster analysis uses four selected weather elements belonging to different rotated factors. They are the diurnal mean values of temperature, of relative humidity, of cloudiness and of wind speed. From the possible ways of hierarchical cluster analysis (i.e. no a priori assumption on the number of classes, the method of furthest neighbours is selected, indicating the arguments of this decision in the paper. These local weather types are important tools in understanding the role of weather in various environmental indicators, in climatic generalisation of short samples by stratified sampling and in interpretation of the climate change.

  14. Comparison of the skeletal and dental changes of tooth-borne vs. bone-borne expansion devices in surgically assisted rapid palatal expansion: A finite element study

    Directory of Open Access Journals (Sweden)

    Azita Tehranchi

    2013-01-01

    Conclusion: Closer teeth feel more stress and undergo more displacement than the farther ones. Moreover, skeletal effects of the Smile distractor were greater than of Hyrax in all different positions.

  15. Working memory load can both improve and impair selective attention: evidence from the Navon paradigm.

    Science.gov (United States)

    Ahmed, Lubna; de Fockert, Jan W

    2012-10-01

    Selective attention to relevant targets has been shown to depend on the availability of working memory (WM). Under conditions of high WM load, processing of irrelevant distractors is enhanced. Here we showed that this detrimental effect of WM load on selective attention efficiency is reversed when the task requires global- rather than local-level processing. Participants were asked to attend to either the local or the global level of a hierarchical Navon stimulus while keeping either a low or a high load in WM. In line with previous findings, during attention to the local level, distractors at the global level produced more interference under high than under low WM load. By contrast, loading WM had the opposite effect of improving selective attention during attention to the global level. The findings demonstrate that the impact of WM load on selective attention is not invariant, but rather is dependent on the level of the to-be-attended information.

  16. Finite Element Simulation of Sheet Metal Forming Process Using Local Interpolation for Tool Surfaces

    International Nuclear Information System (INIS)

    Hama, Takayuki; Takuda, Hirohiko; Takamura, Masato; Makinouchi, Akitake; Teodosiu, Cristian

    2005-01-01

    Treatment of contact between a sheet and tools is one of the most difficult problems to deal with in finite-element simulations of sheet forming processes. In order to obtain more accurate tool models without increasing the number of elements, this paper describes a new formulation for contact problems using interpolation proposed by Nagata for tool surfaces. A contact search algorithm between sheet nodes and the interpolated tool surfaces was developed and was introduced into the static-explicit elastoplastic finite-element method code STAMP3D. Simulations of a square cup deep drawing process with a very coarsely discretized punch model were carried out. The simulated results showed that the proposed algorithm gave the proper drawn shape, demonstrating the validity of the proposed algorithm

  17. Local Material as a Character of Contemporary Interior Design in Indonesia

    Science.gov (United States)

    Susanto, Dalhar; Puti Angelia, Dini; Ningsih, Tria Amalia

    2017-12-01

    Excellent design needs to fulfill universal requirements (utility, aesthetic, ergonomic, durability, and safe). Besides of all the requirements, an excellent design has to be shown its distinctiveness, uniqueness, and identity. To create an excellent design, we can use one of locality approach, it means local material utilization. From time to time, the material is linking each other in unity with environment context, human, knowledge, culture, social, economy, user needs and material availability. The aspects are the important part to get the reflective identity and local values in architecture and interior design work in Indonesia. It can be proofed by some of the architecture and interior work precedent, like traditional or vernacular in Nusantara or contemporary interior design work from Indonesian designer who has recognized to promote the locality value. However interior design works in Indonesia cannot be shown the characteristic of Indonesia identity and locality currently, it is different than another country work, like Japan, Italy, or Scandinavia. Interior design work from these countries can be easily known with accentuating of characteristic their places, such as material, color, detail, or geometry pattern in the product that has been produced. Meanwhile, some of the region in Indonesia are tropical climate and brought about much of local material and it has potential to make a unique work which has the local identity. This paper will discuss the result of a searching potential of local material usefulness as interior design identity in Indonesia. This research is done by typology method, which means discover the presence of some of the architecture elements appears to be related material. The elements are the pattern, color, craftsmanship, building element, object, and type of material in some of the contemporary interior design work in Indonesia were considered superior and capable of lifting elements recognized locality.

  18. ELEMENTS OF SAFETY IN PARAGLIDING

    Directory of Open Access Journals (Sweden)

    Janez Mekinc

    2016-06-01

    Full Text Available Paragliding is an opportunity for tourism development, depending on what position the sport has place in the local community, the restrictions for paragliders and the safety components of the region. The paper explores the phenomenon of paragliding and safety elements in the Upper Soča region, one of ten best paragliding sites in the world (Placestoseeinyourlifetime, 2015. The purpose of the research is to analyse the safety elements, the development and the risk of paragliding.The goals of the research are to propose solutions in order to improve the safety conditions for paragliding and to make suggestions on the further development of paragliding within the framework of tourism in the Upper Soča destination. According to the interviewees, paragliding is becoming safer from year to year. This is also supported with the ever-growing numbers of pilots, and on the other hand, the number of accidents that do not follow the same trend. The identified causes for the accidents are human errors or weather conditions. The statistical data confirmed the paragliding in the Upper Soča region, with its unique geographical location, has a positive impact on local tourism and its development. The results of the study are useful for paragliders, local tourism stakeholders, researchers of sport tourism, as well to municipalities in the Upper Soča region.

  19. Biomonitoring of trace metal elements by lichens of the Western Pyrenees.Study of elemental and isotopic signature of mercury

    OpenAIRE

    Queipo Abad, Silvia

    2012-01-01

    The lichens, organisms originated by symbiotic relationship between an algae and a fungus, have shown good properties as biomonitors of pollution from Trace Metal Elements. They can be used as indicators of local and long-range atmospheric pollution. The assessment of deposition of atmospheric pollutants results difficult to know their long term impact. This happens specially when the study is focalized in remote areas. In this project it has been developed the elemental and isotopic analy...

  20. Science & Technology, Development and Local Power: Elements for Analysis of the Brazilian Context

    Directory of Open Access Journals (Sweden)

    Sueli Goulart

    2007-03-01

    Full Text Available This paper discusses the theoretical aspects of the relationship between scientific and technological production of universities and local development. The central argument is that this relationship is potentialized when produced knowledge permits the occupation of a position in the scientific field and is linked to specific forms of local insertion. In the context of globalization, which keeps the center-periphery structure of the world economic system practically intact, articulation is proposed between global and local dimensions of the environment. The recovery of theoretical-empirical categories formulated by Economic Commission for Latin-America and the Caribbean helps to place the discussion in a political sphere, and to characterize local development as an expression of social change on territorially demarcated scales.

  1. A compilation of necessary elements for a local government continuity of operations plan

    OpenAIRE

    Cashen, Kevin M.

    2006-01-01

    CHDS State/Local National and state homeland security strategies call for continuity of operations plan development. The 2006 Nationwide Plan Review Phase II Report identifies continuity of operations plan development as a state and local goal with a federal goal of providing continuity of operations plan development support. Most local governments do not have a continuity of operation plan or it needs to be updated. Continuity of operations plan guidance is provided by a variety of intern...

  2. Numerical Investigations on Several Stabilized Finite Element Methods for the Stokes Eigenvalue Problem

    Directory of Open Access Journals (Sweden)

    Pengzhan Huang

    2011-01-01

    Full Text Available Several stabilized finite element methods for the Stokes eigenvalue problem based on the lowest equal-order finite element pair are numerically investigated. They are penalty, regular, multiscale enrichment, and local Gauss integration method. Comparisons between them are carried out, which show that the local Gauss integration method has good stability, efficiency, and accuracy properties, and it is a favorite method among these methods for the Stokes eigenvalue problem.

  3. An object-oriented decomposition of the adaptive-hp finite element method

    Energy Technology Data Exchange (ETDEWEB)

    Wiley, J.C.

    1994-12-13

    Adaptive-hp methods are those which use a refinement control strategy driven by a local error estimate to locally modify the element size, h, and polynomial order, p. The result is an unstructured mesh in which each node may be associated with a different polynomial order and which generally require complex data structures to implement. Object-oriented design strategies and languages which support them, e.g., C++, help control the complexity of these methods. Here an overview of the major classes and class structure of an adaptive-hp finite element code is described. The essential finite element structure is described in terms of four areas of computation each with its own dynamic characteristics. Implications of converting the code for a distributed-memory parallel environment are also discussed.

  4. MESHREF, Finite Elements Mesh Combination with Renumbering

    International Nuclear Information System (INIS)

    1973-01-01

    1 - Nature of physical problem solved: The program can assemble different meshes stored on tape or cards. Renumbering is performed in order to keep band width low. Voids and/ or local refinement are possible. 2 - Method of solution: Topology and geometry are read according to input specifications. Abundant nodes and elements are eliminated. The new topology and geometry are stored on tape. 3 - Restrictions on the complexity of the problem: Maximum number of nodes = 2000. Maximum number of elements = 1500

  5. Evidence inhibition responds reactively to the salience of distracting information during focused attention.

    Directory of Open Access Journals (Sweden)

    Natalie Wyatt

    Full Text Available Along with target amplification, distractor inhibition is regarded as a major contributor to selective attention. Some theories suggest that the strength of inhibitory processing is proportional to the salience of the distractor (i.e., inhibition reacts to the distractor intensity. Other theories suggest that the strength of inhibitory processing does not depend on the salience of the distractor (i.e., inhibition does not react to the distractor intensity. The present study aimed to elucidate the relationship between the intensity of a distractor and its subsequent inhibition during focused attention. A flanker task with a variable distractor-target stimulus-onset asynchrony (SOA was used to measure both distractor interference and distractor inhibition. We manipulated the intensity of the distractor in two separate ways, by varying its distance from the target (Experiment 1 and by varying its brightness (Experiment 2. The results indicate that more intense distractors were associated with both increased interference and stronger distractor inhibition. The latter outcome provides novel support for the reactive inhibition hypothesis, which posits that inhibition reacts to the strength of distractor input, such that more salient distractors elicit stronger inhibition.

  6. Topology Optimization Using Multiscale Finite Element Method for High-Contrast Media

    DEFF Research Database (Denmark)

    Lazarov, Boyan Stefanov

    2014-01-01

    The focus of this paper is on the applicability of multiscale finite element coarse spaces for reducing the computational burden in topology optimization. The coarse spaces are obtained by solving a set of local eigenvalue problems on overlapping patches covering the computational domain. The app......The focus of this paper is on the applicability of multiscale finite element coarse spaces for reducing the computational burden in topology optimization. The coarse spaces are obtained by solving a set of local eigenvalue problems on overlapping patches covering the computational domain...

  7. A Laser Induced Breakdown Spectroscopy application based on Local Thermodynamic Equilibrium assumption for the elemental analysis of alexandrite gemstone and copper-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    De Giacomo, A. [Department of Chemistry, University of Bari, Via Orabona 4, 70126 Bari (Italy); Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Dell' Aglio, M. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Gaudiuso, R., E-mail: rosalba.gaudiuso@ba.imip.cnr.it [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Santagata, A. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Potenza, Via S. Loja, Zona Ind., 85050 Tito Scalo (PZ) (Italy); Senesi, G.S. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Rossi, M.; Ghiara, M.R. [Department of Earth Sciences, University of Naples ' Federico II' , Via Mezzocannone 8, 80134 Naples (Italy); Capitelli, F. [Institute of Crystallography - CNR, Via Salaria Km 29.300, 00015 Monterotondo (Roma) (Italy); De Pascale, O. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy)

    2012-04-04

    Graphical abstract: Self-calibrated analytical techniques based on the approximation of Local Thermodynamic Equilibrium (LTE) have been employed for the analysis of gemstones and copper-based alloys by LIBS (Laser Induced Breakdown Spectroscopy), with a special focus on LTE conditions in laser induced plasmas. Highlights: Black-Right-Pointing-Pointer Discussion of Local Thermodynamic Equilibrium (LTE) condition in laser-induced plasmas. Black-Right-Pointing-Pointer LIBS enables elemental analysis with self-calibrated LTE-based methods. Black-Right-Pointing-Pointer Be detection in alexandrite gemstone is made possible by LIBS. - Abstract: Laser Induced Breakdown Spectroscopy (LIBS) is an appealing technique to study laser-induced plasmas (LIPs), both from the basic diagnostics point of view and for analytical applications. LIPs are complex dynamic systems, expanding at supersonic velocities and undergoing a transition between different plasma regimes. If the Local Thermodynamic Equilibrium (LTE) condition is valid for such plasmas, several analytical methods can be employed and fast quantitative analyses can be performed on a variety of samples. In the present paper, a discussion about LTE is carried out and an innovative application to the analysis of the alexandrite gemstone is presented. In addition, a study about the influence of plasma parameters on the performance of LTE-based methods is reported for bronze and brass targets.

  8. Local defect correction for boundary integral equation methods

    NARCIS (Netherlands)

    Kakuba, G.; Anthonissen, M.J.H.

    2014-01-01

    The aim in this paper is to develop a new local defect correction approach to gridding for problems with localised regions of high activity in the boundary element method. The technique of local defect correction has been studied for other methods as finite difference methods and finite volume

  9. Experimental characterization and numerical simulation of riveted lap-shear joints using Rivet Element

    Science.gov (United States)

    Vivio, Francesco; Fanelli, Pierluigi; Ferracci, Michele

    2018-03-01

    In aeronautical and automotive industries the use of rivets for applications requiring several joining points is now very common. In spite of a very simple shape, a riveted junction has many contact surfaces and stress concentrations that make the local stiffness very difficult to be calculated. To overcome this difficulty, commonly finite element models with very dense meshes are performed for single joint analysis because the accuracy is crucial for a correct structural analysis. Anyhow, when several riveted joints are present, the simulation becomes computationally too heavy and usually significant restrictions to joint modelling are introduced, sacrificing the accuracy of local stiffness evaluation. In this paper, we tested the accuracy of a rivet finite element presented in previous works by the authors. The structural behaviour of a lap joint specimen with a rivet joining is simulated numerically and compared to experimental measurements. The Rivet Element, based on a closed-form solution of a reference theoretical model of the rivet joint, simulates local and overall stiffness of the junction combining high accuracy with low degrees of freedom contribution. In this paper the Rivet Element performances are compared to that of a FE non-linear model of the rivet, built with solid elements and dense mesh, and to experimental data. The promising results reported allow to consider the Rivet Element able to simulate, with a great accuracy, actual structures with several rivet connections.

  10. CMPO-calix[4]arenes with spacer containing intramolecular hydrogen bonding: Effect of local rigidification on solvent extraction toward f-block elements

    International Nuclear Information System (INIS)

    Chu, Hongzhu; He, Lutao; Jiang, Qian; Fang, Yuyu; Jia, Yiming; Yuan, Xiangyang; Zou, Shuliang; Li, Xianghui; Feng, Wen; Yang, Yuanyou; Liu, Ning; Luo, Shunzhong; Yang, Yanqiu; Yang, Liang; Yuan, Lihua

    2014-01-01

    Highlights: • Three CMPO-calix[4]arenes with spacer containing intramolecular hydrogen bonds were designed and synthesized. • The influence of local rigidification caused by intramolecular hydrogen bonds upon extraction of f-elements was investigated. • Selective extraction is realized via tuning local chelating surroundings by aid of intramolecular hydrogen bonds. -- Abstract: To understand intramolecular hydrogen bonding in effecting liquid–liquid extraction behavior of CMPO-calixarenes, three CMPO-modified calix[4]arenes (CMPO-CA) 5a–5c with hydrogen-bonded spacer were designed and synthesized. The impact of spacer rotation that is hindered by introduction of intramolecular hydrogen bonding upon extraction of La 3+ , Eu 3+ , Yb 3+ , Th 4+ , and UO 2 2+ has been examined. The results show that 5b and 5c containing only one hydrogen bond with a less hindered rotation spacer extract La 3+ more efficiently than 5a containing two hydrogen bonds with a more hindered rotation spacer, demonstrating the importance of local rigidification of spacer in the design of extractants in influencing the coordination environment. The large difference in extractability between La 3+ and Yb 3+ (or Eu 3+ ) by 5b (or 5c), and the small difference by 5a, suggests intramolecular hydrogen bonding do exert pronounced influence upon selective extraction of light and heavy lanthanides. Log–log plot analysis indicates a 1:1, 2:1 and 1:1 stoichiometry (ligand/metal) for the extracted complex formed between 5b and La 3+ , Th 4+ , UO 2 2+ , respectively. Additionally, their corresponding acyclic analogs 7a–7c exhibit negligible extraction toward these metal ions. These results reveal the possibility of selective extraction via tuning local chelating surroundings of CMPO-CA by aid of intramolecular hydrogen bonding

  11. Phase-Field Relaxation of Topology Optimization with Local Stress Constraints

    DEFF Research Database (Denmark)

    Stainko, Roman; Burger, Martin

    2006-01-01

    inequality constraints. We discretize the problem by finite elements and solve the arising finite-dimensional programming problems by a primal-dual interior point method. Numerical experiments for problems with local stress constraints based on different criteria indicate the success and robustness......We introduce a new relaxation scheme for structural topology optimization problems with local stress constraints based on a phase-field method. In the basic formulation we have a PDE-constrained optimization problem, where the finite element and design analysis are solved simultaneously...

  12. A digital local studies collection

    Directory of Open Access Journals (Sweden)

    Simona Resman

    2005-01-01

    Full Text Available Local studies and local studies departments reflect the entire spectrum of knowledge within the local community. Transition to the new digital environment means just continuing the basic functions of local studies collections: acquisition, cataloguing and preservation of materials in different formats on different media. The background of each digital library is the technical architecture of system that enables interaction between the user and the library, saving digital material and building a platform for searching and indexing digital objects. Using advanced ICT requests from librarians, designers of digital local studies collections a reflection about traditional roles. A digital local studies collection with new technology enlarges local boarders, local contents become more and more interesting for a wider sphere of people. In collecting of local materials a collaboration with archives and museums, with academic community, with community groups and with individuals comes in forefront. Digital local studies collections with their contents support local diversity, lifelong learning and social inclusion. The crucial elements of a digital local studies collection are attractive local contents with fast and simple access from one place – a portal. In the digital age public libraries become managers of knowledge also by establishing digital local studies collections.

  13. A consistent partly cracked XFEM element for cohesive crack growth

    DEFF Research Database (Denmark)

    Asferg, Jesper L.; Poulsen, Peter Noe; Nielsen, Leif Otto

    2007-01-01

    Present extended finite element method (XFEM) elements for cohesive crack growth may often not be able to model equal stresses on both sides of the discontinuity when acting as a crack-tip element. The authors have developed a new partly cracked XFEM element for cohesive crack growth with extra...... enrichments to the cracked elements. The extra enrichments are element side local and were developed by superposition of the standard nodal shape functions for the element and standard nodal shape functions for a sub-triangle of the cracked element. With the extra enrichments, the crack-tip element becomes...... capable of modelling variations in the discontinuous displacement field on both sides of the crack and hence also capable of modelling the case where equal stresses are present on each side of the crack. The enrichment was implemented for the 3-node constant strain triangle (CST) and a standard algorithm...

  14. Tightening the rules for local expenditure in Denmark

    DEFF Research Database (Denmark)

    Sørensen, Eva Moll

    was established in reaction to the 1970s economic crisis, and it has developed into a central element in central-local government relations. For example, the agreements are also used to formulate common performance targets in policy areas such as education or social policy. Originally, it was up to local...

  15. A finite element method for solving the shallow water equations on the sphere

    Science.gov (United States)

    Comblen, Richard; Legrand, Sébastien; Deleersnijder, Eric; Legat, Vincent

    Within the framework of ocean general circulation modeling, the present paper describes an efficient way to discretize partial differential equations on curved surfaces by means of the finite element method on triangular meshes. Our approach benefits from the inherent flexibility of the finite element method. The key idea consists in a dialog between a local coordinate system defined for each element in which integration takes place, and a nodal coordinate system in which all local contributions related to a vectorial degree of freedom are assembled. Since each element of the mesh and each degree of freedom are treated in the same way, the so-called pole singularity issue is fully circumvented. Applied to the shallow water equations expressed in primitive variables, this new approach has been validated against the standard test set defined by [Williamson, D.L., Drake, J.B., Hack, J.J., Jakob, R., Swarztrauber, P.N., 1992. A standard test set for numerical approximations to the shallow water equations in spherical geometry. Journal of Computational Physics 102, 211-224]. Optimal rates of convergence for the P1NC-P1 finite element pair are obtained, for both global and local quantities of interest. Finally, the approach can be extended to three-dimensional thin-layer flows in a straightforward manner.

  16. Local variances in biomonitoring

    International Nuclear Information System (INIS)

    Wolterbeek, H.Th; Verburg, T.G.

    2001-01-01

    The present study was undertaken to explore possibilities to judge survey quality on basis of a limited and restricted number of a-priori observations. Here, quality is defined as the ratio between survey and local variance (signal-to-noise ratio). The results indicate that the presented surveys do not permit such judgement; the discussion also suggests that the 5-fold local sampling strategies do not merit any sound judgement. As it stands, uncertainties in local determinations may largely obscure possibilities to judge survey quality. The results further imply that surveys will benefit from procedures, controls and approaches in sampling and sample handling, to assess both average, variance and the nature of the distribution of elemental concentrations in local sites. This reasoning is compatible with the idea of the site as a basic homogeneous survey unit, which is implicitly and conceptually underlying any survey performed. (author)

  17. Asynchronous variational integration using continuous assumed gradient elements.

    Science.gov (United States)

    Wolff, Sebastian; Bucher, Christian

    2013-03-01

    Asynchronous variational integration (AVI) is a tool which improves the numerical efficiency of explicit time stepping schemes when applied to finite element meshes with local spatial refinement. This is achieved by associating an individual time step length to each spatial domain. Furthermore, long-term stability is ensured by its variational structure. This article presents AVI in the context of finite elements based on a weakened weak form (W2) Liu (2009) [1], exemplified by continuous assumed gradient elements Wolff and Bucher (2011) [2]. The article presents the main ideas of the modified AVI, gives implementation notes and a recipe for estimating the critical time step.

  18. Localized magnetic fields in arbitrary directions using patterned nanomagnets

    DEFF Research Database (Denmark)

    McNeil, Robert P G; Schneble, Jeff; Kataoka, Masaya

    2010-01-01

    Control of the local magnetic fields desirable for spintronics and quantum information technology is not well developed. Existing methods produce either moderately small local fields or one held orientation. We present designs of patterned magnetic elements that produce remanent fields of 50 mT (...

  19. Simulation of strain localization in polycrystals

    International Nuclear Information System (INIS)

    Deryugin, Ye.Ye.; Payuk, V.A.; Lasko, G.V.

    2002-01-01

    In the work simulation of plastic deformation evolution is presented for the case of polycrystals under external loading. Strain localization in polycrystal is simulated analytically following an unconventional method. The model is based on new progressive relaxation elements methods. Emphasis of the model is combining of discrete methods and continual approach. It makes possible to present local sites of plastic deformation analytically in a continuous medium and to calculate their respective no uniform stress field

  20. Cleavage mechanoluminescence in elemental and III-V semiconductors

    International Nuclear Information System (INIS)

    Chandra, B.P.; Patel, R.P.; Gour, Anubha S.; Chandra, V.K.; Gupta, R.K.

    2003-01-01

    The present paper reports the theory of mechanoluminescence (ML) produced during cleavage of elemental and III-V semiconductors. It seems that the formation of crack-induced localized states is responsible for the ML excitation produced during the cleavage of elemental and III-V semiconductors. According to this mechanism, as the atoms are drawn away from each other in an advancing crack tip, the decreasing wave function overlap across the crack may result in localized states which is associated with increasing electron energy. If the energy of these localized states approach that of the conduction band, transition to the conduction band via tunnelling would be possible, creating minority carriers, and consequently the electron-hole recombination may give rise to mechanoluminescence. When an elemental or III-V semiconductor is cleaved, initially the ML intensity increases with time, attains a peak value I m at the time t m corresponding to completion of the cleavage of the semiconductor, and then it decreases following power law decay. Expressions are derived for the ML intensity I m corresponding to the peak of the ML intensity versus time curve and for the total ML intensity I T . It is shown that both I m and I T should increase directly with the area of the newly created surfaces of the crystals. From the measurements of the ML intensity, the velocity of crack propagation in material can be determined by using the relation v=H/t m

  1. A study on the nonlinear finite element analysis of reinforced concrete structures: shell finite element formulation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Jin; Seo, Jeong Moon

    2000-08-01

    The main goal of this research is to establish a methodology of finite element analysis of containment building predicting not only global behaviour but also local failure mode. In this report, we summerize some existing numerical analysis techniques to be improved for containment building. In other words, a complete description of the standard degenerated shell finite element formulation is provided for nonlinear stress analysis of nuclear containment structure. A shell finite element is derived using the degenerated solid concept which does not rely on a specific shell theory. Reissner-Mindlin assumptions are adopted to consider the transverse shear deformation effect. In order to minimize the sensitivity of the constitutive equation to structural types, microscopic material model is adopted. The four solution algorithms based on the standard Newton-Raphson method are discussed. Finally, two numerical examples are carried out to test the performance of the adopted shell medel.

  2. A study on the nonlinear finite element analysis of reinforced concrete structures: shell finite element formulation

    International Nuclear Information System (INIS)

    Lee, Sang Jin; Seo, Jeong Moon

    2000-08-01

    The main goal of this research is to establish a methodology of finite element analysis of containment building predicting not only global behaviour but also local failure mode. In this report, we summerize some existing numerical analysis techniques to be improved for containment building. In other words, a complete description of the standard degenerated shell finite element formulation is provided for nonlinear stress analysis of nuclear containment structure. A shell finite element is derived using the degenerated solid concept which does not rely on a specific shell theory. Reissner-Mindlin assumptions are adopted to consider the transverse shear deformation effect. In order to minimize the sensitivity of the constitutive equation to structural types, microscopic material model is adopted. The four solution algorithms based on the standard Newton-Raphson method are discussed. Finally, two numerical examples are carried out to test the performance of the adopted shell medel

  3. [Nodules on localized scleroderma or morphea].

    Science.gov (United States)

    Bayle, P; Bazex, J; Marguery, M-C; Lamant, L

    2005-02-01

    Localized scleroderma or morphea usually appears as flat or depressed lesions. We report 3 cases of morphea with atypical appearance, alternating pigmented and depigmented patches with nodules or sclerous bands, occurring in adult men. The occurrence of nodular elements on generalized or localized scleroderma, although rare, was first reported in the literature by Addisson in 1884. These nodules usually appear during evolution. These scleroderma are then described as being keloidal or nodular. We report 3 cases of nodules on localized scleroderma which appeared at the beginning of the dermatosis and where the scleroderma had a similar unusual irregularly pigmented appearance.

  4. Biomechanical evaluation of sagittal maxillary internal distraction osteogenesis in unilateral cleft lip and palate patient and noncleft patients: a three-dimensional finite element analysis.

    Science.gov (United States)

    Olmez, Sultan; Dogan, Servet; Pekedis, Mahmut; Yildiz, Hasan

    2014-09-01

    To compare the pattern and amount of stress and displacement during maxillary sagittal distraction osteogenesis (DO) between a patient with unilateral cleft lip and palate (UCLP) and a noncleft patient. Three-dimensional finite element models for both skulls were constructed. Displacements of the surface landmarks and stress distributions in the circummaxillary sutures were analyzed after an anterior displacement of 6 mm was loaded to the elements where the inferior plates of the distractor were assumed to be fixed and were below the Le Fort I osteotomy line. In sagittal plane, more forward movement was found on the noncleft side in the UCLP model (-6.401 mm on cleft side and -6.651 mm on noncleft side for the central incisor region). However, similar amounts of forward movement were seen in the control model. In the vertical plane, a clockwise rotation occurred in the UCLP model, whereas a counterclockwise rotation was seen in the control model. The mathematical UCLP model also showed higher stress values on the sutura nasomaxillaris, frontonasalis, and zygomatiomaxillaris on the cleft side than on the normal side. Not only did the sagittal distraction forces produce advancement forces at the intermaxillary sutures, but more stress was also present on the sutura nasomaxillaris, sutura frontonasalis, and sutura zygomaticomaxillaris on the cleft side than on the noncleft side.

  5. Two-dimensional finite element neutron diffusion analysis using hierarchic shape functions

    International Nuclear Information System (INIS)

    Carpenter, D.C.

    1997-01-01

    Recent advances have been made in the use of p-type finite element method (FEM) for structural and fluid dynamics problems that hold promise for reactor physics problems. These advances include using hierarchic shape functions, element-by-element iterative solvers and more powerful mapping techniques. Use of the hierarchic shape functions allows greater flexibility and efficiency in implementing energy-dependent flux expansions and incorporating localized refinement of the solution space. The irregular matrices generated by the p-type FEM can be solved efficiently using element-by-element conjugate gradient iterative solvers. These solvers do not require storage of either the global or local stiffness matrices and can be highly vectorized. Mapping techniques based on blending function interpolation allow exact representation of curved boundaries using coarse element grids. These features were implemented in a developmental two-dimensional neutron diffusion program based on the use of hierarchic shape functions (FEM2DH). Several aspects in the effective use of p-type analysis were explored. Two choices of elemental preconditioning were examined--the proper selection of the polynomial shape functions and the proper number of functions to use. Of the five shape function polynomials tested, the integral Legendre functions were the most effective. The serendipity set of functions is preferable over the full tensor product set. Two global preconditioners were also examined--simple diagonal and incomplete Cholesky. The full effectiveness of the finite element methodology was demonstrated on a two-region, two-group cylindrical problem but solved in the x-y coordinate space, using a non-structured element grid. The exact, analytic eigenvalue solution was achieved with FEM2DH using various combinations of element grids and flux expansions

  6. The Local Agenda 21 Planning Guide: An Introduction to ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    The Local Agenda 21 Planning Guide is an introductory guide on the planning elements, methods, and tools being used by local governments to implement Agenda ... International Water Resources Association, in close collaboration with IDRC, is holding a webinar titled “Climate change and adaptive water management: ...

  7. Bending Response of Cross-Ply Laminated Composite Plates with Diagonally Perturbed Localized Interfacial Degeneration

    Directory of Open Access Journals (Sweden)

    Chee Zhou Kam

    2013-01-01

    Full Text Available A laminated composite plate element with an interface description is developed using the finite element approach to investigate the bending performance of two-layer cross-ply laminated composite plates in presence of a diagonally perturbed localized interfacial degeneration between laminae. The stiffness of the laminate is expressed through the assembly of the stiffnesses of lamina sub-elements and interface element, the latter of which is formulated adopting the well-defined virtually zero-thickness concept. To account for the extent of both shear and axial weak bonding, a degeneration ratio is introduced in the interface formulation. The model has the advantage of simulating a localized weak bonding at arbitrary locations, with various degeneration areas and intensities, under the influence of numerous boundary conditions since the interfacial description is expressed discretely. Numerical results show that the bending behavior of laminate is significantly affected by the aforementioned parameters, the greatest effect of which is experienced by those with a localized total interface degeneration, representing the case of local delamination.

  8. Thaumatin-like proteins are differentially expressed and localized in phloem tissues of hybrid poplar

    Directory of Open Access Journals (Sweden)

    Dafoe Nicole J

    2010-08-01

    Full Text Available Abstract Background Two thaumatin-like proteins (TLPs were previously identified in phloem exudate of hybrid poplar (Populus trichocarpa × P. deltoides using proteomics methods, and their sieve element localization confirmed by immunofluorescence. In the current study, we analyzed different tissues to further understand TLP expression and localization in poplar, and used immunogold labelling to determine intracellular localization. Results Immunofluorescence using a TLP antiserum confirmed the presence of TLP in punctate, organelle-like structures within sieve elements. On western blots, the antiserum labeled two constitutively expressed proteins with distinct expression patterns. Immunogold labelling suggested that TLPs are associated with starch granules and starch-containing plastids in sieve elements and phloem parenchyma cells. In addition, the antiserum recognized TLPs in the inner cell wall and sieve plate region of sieve elements. Conclusions TLP localization in poplar cells and tissues is complex. TLP1 is expressed predominantly in tissues with a prominent vascular system such as midveins, petioles and stems, whereas the second TLP is primarily expressed in starch-storing plastids found in young leaves and the shoot apex.

  9. Trace elemental imaging of rare earth elements discriminates tissues at microscale in flat fossils.

    Science.gov (United States)

    Gueriau, Pierre; Mocuta, Cristian; Dutheil, Didier B; Cohen, Serge X; Thiaudière, Dominique; Charbonnier, Sylvain; Clément, Gaël; Bertrand, Loïc

    2014-01-01

    The interpretation of flattened fossils remains a major challenge due to compression of their complex anatomies during fossilization, making critical anatomical features invisible or hardly discernible. Key features are often hidden under greatly preserved decay prone tissues, or an unpreparable sedimentary matrix. A method offering access to such anatomical features is of paramount interest to resolve taxonomic affinities and to study fossils after a least possible invasive preparation. Unfortunately, the widely-used X-ray micro-computed tomography, for visualizing hidden or internal structures of a broad range of fossils, is generally inapplicable to flattened specimens, due to the very high differential absorbance in distinct directions. Here we show that synchrotron X-ray fluorescence spectral raster-scanning coupled to spectral decomposition or a much faster Kullback-Leibler divergence based statistical analysis provides microscale visualization of tissues. We imaged exceptionally well-preserved fossils from the Late Cretaceous without needing any prior delicate preparation. The contrasting elemental distributions greatly improved the discrimination of skeletal elements material from both the sedimentary matrix and fossilized soft tissues. Aside content in alkaline earth elements and phosphorus, a critical parameter for tissue discrimination is the distinct amounts of rare earth elements. Local quantification of rare earths may open new avenues for fossil description but also in paleoenvironmental and taphonomical studies.

  10. Utility-based early modulation of processing distracting stimulus information.

    Science.gov (United States)

    Wendt, Mike; Luna-Rodriguez, Aquiles; Jacobsen, Thomas

    2014-12-10

    Humans are selective information processors who efficiently prevent goal-inappropriate stimulus information to gain control over their actions. Nonetheless, stimuli, which are both unnecessary for solving a current task and liable to cue an incorrect response (i.e., "distractors"), frequently modulate task performance, even when consistently paired with a physical feature that makes them easily discernible from target stimuli. Current models of cognitive control assume adjustment of the processing of distractor information based on the overall distractor utility (e.g., predictive value regarding the appropriate response, likelihood to elicit conflict with target processing). Although studies on distractor interference have supported the notion of utility-based processing adjustment, previous evidence is inconclusive regarding the specificity of this adjustment for distractor information and the stage(s) of processing affected. To assess the processing of distractors during sensory-perceptual phases we applied EEG recording in a stimulus identification task, involving successive distractor-target presentation, and manipulated the overall distractor utility. Behavioral measures replicated previously found utility modulations of distractor interference. Crucially, distractor-evoked visual potentials (i.e., posterior N1) were more pronounced in high-utility than low-utility conditions. This effect generalized to distractors unrelated to the utility manipulation, providing evidence for item-unspecific adjustment of early distractor processing to the experienced utility of distractor information. Copyright © 2014 the authors 0270-6474/14/3416720-06$15.00/0.

  11. Local strains in waste tank deflagration analysis

    International Nuclear Information System (INIS)

    Bryan, B.J.; Flanders, H.E. Jr.

    1993-01-01

    In recent years extensive effort has been expended to qualify buried nuclear waste storage tanks under accident conditions. One of these conditions is deflagration of the combustible gases which may build up over time. While much work has been done to calculate the general strain state, less effort has been made to address the local strains at structural discontinuities. An analytical method is presented for calculating these local strains and combining them with the general strain state. A closed form solution of the local strains is compared to a finite element solution

  12. Simple one-dimensional finite element algorithm with multi-dimensional capabilities

    International Nuclear Information System (INIS)

    Pepper, D.W.; Baker, A.J.

    1978-01-01

    The application of the finite element procedure for the solution of partial differential equations is gaining widespread acceptance. The ability of the finite element procedure to solve problems which are arbitrarily shaped as well as the alleviation of boundary condition problems is well known. By using local interpolation functionals over each subdomain, or element, a set of linearized algebraic equations are obtained which can be solved using any direct, iterative, or inverse numerical technique. Subsequent use of an explicit or implicit integration procedure permits closure of the solution over the global domain

  13. Elemental analysis of traditional medicinal seeds by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Khaled, S.; Mouzai, M.; Ararem, A.; Hamidatou, L.; Zouranen, B.

    2009-01-01

    Traditional medicinal seeds prescribed for specific treatment purposes, were purchased from local markets and analyzed by INAA. The samples were irradiated at Es-Salam research reactor, at a power of 5 MWfor 6 h. The accuracy of the method was established by analyzing reference materials. Twenty elements were measured, with good accuracy and reproducibility. The concentration of elements determined, was found to vary depending on the seeds. The daily intake of essential and toxic elements was determined, and compared with the recommended values. The probable cumulative intake of toxic elements is well below the tolerance limits. (author)

  14. Electron and Nucleon Localization Functions of Oganesson: Approaching the Thomas-Fermi Limit

    Science.gov (United States)

    Jerabek, Paul; Schuetrumpf, Bastian; Schwerdtfeger, Peter; Nazarewicz, Witold

    2018-02-01

    Fermion localization functions are used to discuss electronic and nucleonic shell structure effects in the superheavy element oganesson, the heaviest element discovered to date. Spin-orbit splitting in the 7 p electronic shell becomes so large (˜10 eV ) that Og is expected to show uniform-gas-like behavior in the valence region with a rather large dipole polarizability compared to the lighter rare gas elements. The nucleon localization in Og is also predicted to undergo a transition to the Thomas-Fermi gas behavior in the valence region. This effect, particularly strong for neutrons, is due to the high density of single-particle orbitals.

  15. Measures of skin conductance and heart rate in alcoholic men and women during memory performance

    Directory of Open Access Journals (Sweden)

    Kayle S. Sawyer

    2015-05-01

    Full Text Available We examined abnormalities in physiological responses to emotional stimuli associated with long-term chronic alcoholism. Skin conductance responses (SCR and heart rate (HR responses were measured in 32 abstinent alcoholic (ALC and 30 healthy nonalcoholic (NC men and women undergoing an emotional memory task in an MRI scanner. The task required participants to remember the identity of two emotionally-valenced faces presented at the onset of each trial during functional magnetic resonance imaging (fMRI scanning. After viewing the faces, participants saw a distractor image (an alcoholic beverage, nonalcoholic beverage, or scrambled image followed by a single probe face. The task was to decide whether the probe face matched one of the two encoded faces. Skin conductance measurements (before and after the encoded faces, distractor, and probe were obtained from electrodes on the index and middle fingers on the left hand. HR measurements (beats per minute before and after the encoded faces, distractor, and probe were obtained by a pulse oximeter placed on the little finger on the left hand. We expected that, relative to NC participants, the ALC participants would show reduced SCR and HR responses to the face stimuli, and that we would identify greater reactivity to the alcoholic beverage stimuli than to the distractor stimuli unrelated to alcohol. While the beverage type did not differentiate the groups, the ALC group did have reduced skin conductance and HR responses to elements of the task, as compared to the NC group.

  16. A Discrete Element Method Approach to Progressive Localization of Damage in Granular Rocks and Associated Seismicity

    Science.gov (United States)

    Vora, H.; Morgan, J.

    2017-12-01

    Brittle failure in rock under confined biaxial conditions is accompanied by release of seismic energy, known as acoustic emissions (AE). The objective our study is to understand the influence of elastic properties of rock and its stress state on deformation patterns, and associated seismicity in granular rocks. Discrete Element Modeling is used to simulate biaxial tests on granular rocks of defined grain size distribution. Acoustic Energy and seismic moments are calculated from microfracture events as rock is taken to conditions of failure under different confining pressure states. Dimensionless parameters such as seismic b-value and fractal parameter for deformation, D-value, are used to quantify seismic character and distribution of damage in rock. Initial results suggest that confining pressure has the largest control on distribution of induced microfracturing, while fracture energy and seismic magnitudes are highly sensitive to elastic properties of rock. At low confining pressures, localized deformation (low D-values) and high seismic b-values are observed. Deformation at high confining pressures is distributed in nature (high D-values) and exhibit low seismic b-values as shearing becomes the dominant mode of microfracturing. Seismic b-values and fractal D-values obtained from microfracturing exhibit a linear inverse relationship, similar to trends observed in earthquakes. Mode of microfracturing in our simulations of biaxial compression tests show mechanistic similarities to propagation of fractures and faults in nature.

  17. Structural analysis of reactor fuel elements

    International Nuclear Information System (INIS)

    Weeks, R.W.

    1977-01-01

    An overview of fuel-element modeling is presented that traces the development of codes for the prediction of light-water-reactor and fast-breeder-reactor fuel-element performance. It is concluded that although the mathematical analysis is now far advanced, the development and incorporation of mechanistic constitutive equations has not kept pace. The resultant reliance on empirical correlations severely limits the physical insight that can be gained from code extrapolations. Current efforts include modeling of alternate fuel systems, analysis of local fuel-cladding interactions, and development of a predictive capability for off-normal behavior. Future work should help remedy the current constitutive deficiencies and should include the development of deterministic failure criteria for use in design

  18. Two-Dimensional Nonlinear Finite Element Analysis of CMC Microstructures

    Science.gov (United States)

    Mital, Subodh K.; Goldberg, Robert K.; Bonacuse, Peter J.

    2012-01-01

    A research program has been developed to quantify the effects of the microstructure of a woven ceramic matrix composite and its variability on the effective properties and response of the material. In order to characterize and quantify the variations in the microstructure of a five harness satin weave, chemical vapor infiltrated (CVI) SiC/SiC composite material, specimens were serially sectioned and polished to capture images that detailed the fiber tows, matrix, and porosity. Open source quantitative image analysis tools were then used to isolate the constituents, from which two dimensional finite element models were generated which approximated the actual specimen section geometry. A simplified elastic-plastic model, wherein all stress above yield is redistributed to lower stress regions, is used to approximate the progressive damage behavior for each of the composite constituents. Finite element analyses under in-plane tensile loading were performed to examine how the variability in the local microstructure affected the macroscopic stress-strain response of the material as well as the local initiation and progression of damage. The macroscopic stress-strain response appeared to be minimally affected by the variation in local microstructure, but the locations where damage initiated and propagated appeared to be linked to specific aspects of the local microstructure.

  19. n-capture elements in the Sculptor dwarf spheroidal galaxy

    Science.gov (United States)

    Skúladóttir, Ása

    2018-06-01

    Sculptor is a well studied dwarf galaxy in the Local Group, which is dominated by an old stellar population (>10 Gyr) and is therefore an ideal system to study early chemical evolution. With high-resolution VLT/FLAMES spectra, R~20,000, we are able to get accurate abundances of several n-capture elements in ~100 stars, from both the lighter n-capture elements (Y) as well as the heavier ones, both tracers of the s-process (e.g. Ba) and the r-process (e.g. Eu). I will discuss the similarities and differences in the n-capture elements in Sculptor and the Milky Way, as well as other dwarf galaxies.

  20. Socially anxious individuals with low working memory capacity could not inhibit the goal-irrelevant information.

    Science.gov (United States)

    Moriya, Jun; Sugiura, Yoshinori

    2013-01-01

    Socially anxious individuals are interfered by distractors. Recent work has suggested that low working memory capacity and inappropriate temporary goal induce attention to distractors. We investigated the effects of working memory capacity and temporary goal on attention to distractors in social anxiety. Participants viewed a rapid serial visual presentation, in which participants reported the identity of a single target letter drawn in red. Distractors appeared before the target was presented. When the color of distractors was red (i.e., goal-relevant stimuli), low-capacity individuals were strongly interfered by the distractors compared to high-capacity individuals regardless of social anxiety. When the color of distractors was goal-irrelevant, low-capacity and high socially anxious individuals were strongly interfered by the distractors. These results suggest that socially anxious individuals with low working memory capacity could not inhibit the goal-irrelevant information and direct attention to distractors.

  1. Socially Anxious Individuals with Low Working Memory Capacity Could Not Inhibit the Goal-Irrelevant Information

    Directory of Open Access Journals (Sweden)

    Jun eMoriya

    2013-12-01

    Full Text Available Socially anxious individuals are interfered by distractors. Recent work has suggested that low working memory capacity and inappropriate temporary goal induce attentional capture to distractors. We investigated the effects of working memory capacity and temporary goal on attentional capture to distractors in social anxiety. Participants viewed a rapid serial visual presentation, in which participants reported the identity of a single target letter drawn in red. Distractors appeared before the target was presented. When the color of distractors was red (i.e., goal-relevant stimuli, low-capacity individuals were strongly interfered by the distractors compared to high-capacity individuals regardless of social anxiety. When the color of distractors was goal-irrelevant, low-capacity and high socially anxious individuals were strongly interfered by the distractors. These results suggest that socially anxious individuals with low working memory capacity could not inhibit the goal-irrelevant information and direct attention to distractors.

  2. Multivariate localization methods for ensemble Kalman filtering

    KAUST Repository

    Roh, S.; Jun, M.; Szunyogh, I.; Genton, Marc G.

    2015-01-01

    the Schur (element-wise) product of the ensemble-based sample covariance matrix and a correlation matrix whose entries are obtained by the discretization of a distance-dependent correlation function. While the proper definition of the localization function

  3. Critical elements in Carlin, epithermal, and orogenic gold deposits

    Science.gov (United States)

    Goldfarb, Richard J.; Hofstra, Albert H.; Simmons, Stuart F.

    2016-01-01

    Carlin, epithermal, and orogenic gold deposits, today mined almost exclusively for their gold content, have similar suites of anomalous trace elements that reflect similar low-salinity ore fluids and thermal conditions of metal transport and deposition. Many of these trace elements are commonly referred to as critical or near-critical elements or metals and have been locally recovered, although typically in small amounts, by historic mining activities. These elements include As, Bi, Hg, In, Sb, Se, Te, Tl, and W. Most of these elements are now solely recovered as by-products from the milling of large-tonnage, base metal-rich ore deposits, such as porphyry and volcanogenic massive sulfide deposits.A combination of dominance of the world market by a single country for a single commodity and a growing demand for many of the critical to near-critical elements could lead to future recovery of such elements from select epithermal, orogenic, or Carlin-type gold deposits. Antimony continues to be recovered from some orogenic gold deposits and tellurium could potentially be a primary commodity from some such deposits. Tellurium and indium in sphalerite-rich ores have been recovered in the past and could be future commodities recovered from epithermal ores. Carlin-type gold deposits in Nevada are enriched in and may be a future source for As, Hg, Sb, and/or Tl. Some of the Devonian carbonaceous host rocks in the Carlin districts are sufficiently enriched in many trace elements, including Hg, Se, and V, such that they also could become resources. Thallium may be locally enriched to economic levels in Carlin-type deposits and it has been produced from Carlin-like deposits elsewhere in the world (e.g., Alsar, southern Macedonia; Lanmuchang, Guizhou province, China). Mercury continues to be recovered from shallow-level epithermal deposits, as well as a by-product of many Carlin-type deposits where refractory ore is roasted to oxidize carbon and pyrite, and mercury is then

  4. Fluorescence detection of white-beam X-ray absorption anisotropy: towards element-sensitive projections of local atomic structure

    International Nuclear Information System (INIS)

    Korecki, P.; Tolkiehn, M.; Dąbrowski, K. M.; Novikov, D. V.

    2011-01-01

    A method for a direct measurement of X-ray projections of the atomic structure is described. Projections of the atomic structure around Nb atoms in a LiNbO 3 single crystal were obtained from a white-beam X-ray absorption anisotropy pattern detected using Nb K fluorescence. Projections of the atomic structure around Nb atoms in a LiNbO 3 single crystal were obtained from a white-beam X-ray absorption anisotropy (XAA) pattern detected using Nb K fluorescence. This kind of anisotropy results from the interference of X-rays inside a sample and, owing to the short coherence length of a white beam, is visible only at small angles around interatomic directions. Consequently, the main features of the recorded XAA corresponded to distorted real-space projections of dense-packed atomic planes and atomic rows. A quantitative analysis of XAA was carried out using a wavelet transform and allowed well resolved projections of Nb atoms to be obtained up to distances of 10 Å. The signal of nearest O atoms was detected indirectly by a comparison with model calculations. The measurement of white-beam XAA using characteristic radiation indicates the possibility of obtaining element-sensitive projections of the local atomic structure in more complex samples

  5. A local isotropic/global orthotropic finite element technique for modeling the crush of wood in impact limiters

    International Nuclear Information System (INIS)

    Attaway, S.W.; Yoshimura, H.R.

    1989-01-01

    Wood is often used as the energy absorbing material in impact limiters, because it begins to crush at low strains, then maintains a near constant crush stress up to nearly 60% volume reduction, and then locks up. Hill (Hill and Joseph, 1974) has performed tests that show that wood is an excellent absorber. However, wood's orthotropic behavior for large crush is difficult to model. In the past, analysts have used isotropic foam-like material models for modeling wood. A new finite element technique is presented in this paper that gives a better model of wood crush than the model currently in use. The orthotropic technique is based on locally isotropic, but globally orthotropic (LIGO) (Attaway, 1988) assumptions in which alternating layers of hard and soft crushable material are used. Each layer is isotropic; however, by alternating hard and soft thin layers, the resulting global behavior is orthotropic. In the remainder of this paper, the new technique for modeling orthotropic wood crush will be presented. The model is used to predict the crush behavior for different grain orientations of balsa wood. As an example problem, an impact limiter containing balsa wood as the crushable material is analyzed using both an isotropic model and the LIGO model

  6. Connecting the East and the West, the Local and the Universal: The Methodological Elements of a Transcultural Approach to Bioethics.

    Science.gov (United States)

    Nie, Jing-Bao; Fitzgerald, Ruth P

    From the outset, cross-cultural and transglobal bioethics has constituted a potent arena for a dynamic public discourse and academic debate alike. But prominent bioethical debates on such issues as the notion of common morality and a distinctive "Asian" bioethics in contrast to a "Western" one reveal some deeply rooted and still popular but seriously problematic methodological habits in approaching cultural differences, most notably, radically dichotomizing the East and the West, the local and the universal. In this paper, a "transcultural" approach to bioethics and cultural studies is proposed. It takes seriously the challenges offered by social sciences, anthropology in particular, towards the development of new methodologies for comparative and global bioethics. The key methodological elements of "transculturalism" include acknowledging the great internal plurality within every culture; highlighting the complexity of cultural differences; upholding the primacy of morality; incorporating a reflexive theory of social power; and promoting changes or progress towards shared and sometimes new moral values.

  7. The finite element response matrix method

    International Nuclear Information System (INIS)

    Nakata, H.; Martin, W.R.

    1983-02-01

    A new technique is developed with an alternative formulation of the response matrix method implemented with the finite element scheme. Two types of response matrices are generated from the Galerkin solution to the weak form of the diffusion equation subject to an arbitrary current and source. The piecewise polynomials are defined in two levels, the first for the local (assembly) calculations and the second for the global (core) response matrix calculations. This finite element response matrix technique was tested in two 2-dimensional test problems, 2D-IAEA benchmark problem and Biblis benchmark problem, with satisfatory results. The computational time, whereas the current code is not extensively optimized, is of the same order of the well estabilished coarse mesh codes. Furthermore, the application of the finite element technique in an alternative formulation of response matrix method permits the method to easily incorporate additional capabilities such as treatment of spatially dependent cross-sections, arbitrary geometrical configurations, and high heterogeneous assemblies. (Author) [pt

  8. Trace elements in termites by PIXE analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, T. E-mail: tsuyoshi@termite.kuwri.kyoto-u.ac.jp; Kagemori, N.; Kawai, S.; Sera, K.; Futatsugawa, S

    2002-04-01

    Trace elements in a Japanese subterranean xylophagous termite, Coptotermes formosanus Shiraki, were analyzed by the PIXE method. The total amount of the 14 predominant elements out of 27 detected in an intact termite was higher in a soldier termite (23 000 {mu}g/g) than in a worker termite (10 000 {mu}g/g). A block of wood (Pinus densiflora Sieb. et Zucc.) for termite feed had a much lower concentration (3600 {mu}g/g) compared with that in an intact termite. This probably relates the functional bio-condensation and/or bio-recycling of trace elements in C. formosanus. When a termite was separated into three anatomical parts, head, degutted body and gut, the worker gut contained the highest total amount of the 14 predominant measured elements (31 000 {mu}g/g). This might be correlated with the higher activity of food digestion and energy production in the worker gut. Moreover, the mandible of the soldier head, with an exoskeleton that is intensely hardened, showed a preferential distribution of Mn and Fe. These results suggest that the characteristic localization of elements will be closely related to the functional role of the individual anatomical part of C. formosanus.

  9. Trace elemental imaging of rare earth elements discriminates tissues at microscale in flat fossils.

    Directory of Open Access Journals (Sweden)

    Pierre Gueriau

    Full Text Available The interpretation of flattened fossils remains a major challenge due to compression of their complex anatomies during fossilization, making critical anatomical features invisible or hardly discernible. Key features are often hidden under greatly preserved decay prone tissues, or an unpreparable sedimentary matrix. A method offering access to such anatomical features is of paramount interest to resolve taxonomic affinities and to study fossils after a least possible invasive preparation. Unfortunately, the widely-used X-ray micro-computed tomography, for visualizing hidden or internal structures of a broad range of fossils, is generally inapplicable to flattened specimens, due to the very high differential absorbance in distinct directions. Here we show that synchrotron X-ray fluorescence spectral raster-scanning coupled to spectral decomposition or a much faster Kullback-Leibler divergence based statistical analysis provides microscale visualization of tissues. We imaged exceptionally well-preserved fossils from the Late Cretaceous without needing any prior delicate preparation. The contrasting elemental distributions greatly improved the discrimination of skeletal elements material from both the sedimentary matrix and fossilized soft tissues. Aside content in alkaline earth elements and phosphorus, a critical parameter for tissue discrimination is the distinct amounts of rare earth elements. Local quantification of rare earths may open new avenues for fossil description but also in paleoenvironmental and taphonomical studies.

  10. Magnetic elements for switching magnetization magnetic force microscopy tips

    International Nuclear Information System (INIS)

    Cambel, V.; Elias, P.; Gregusova, D.; Martaus, J.; Fedor, J.; Karapetrov, G.; Novosad, V.

    2010-01-01

    Using combination of micromagnetic calculations and magnetic force microscopy (MFM) imaging we find optimal parameters for novel magnetic tips suitable for switching magnetization MFM. Switching magnetization MFM is based on two-pass scanning atomic force microscopy with reversed tip magnetization between the scans. Within the technique the sum of the scanned data with reversed tip magnetization depicts local atomic forces, while their difference maps the local magnetic forces. Here we propose the design and calculate the magnetic properties of tips suitable for this scanning probe technique. We find that for best performance the spin-polarized tips must exhibit low magnetic moment, low switching fields, and single-domain state at remanence. The switching field of such tips is calculated and optimum shape of the Permalloy elements for the tips is found. We show excellent correspondence between calculated and experimental results for Py elements.

  11. Re-framing climate issue by listening to local actors: elements of propaedeutics

    International Nuclear Information System (INIS)

    Bredif, Herve; Bertrand, Francois; Tabeaud, Martine

    2015-01-01

    The disappointing outcomes of international negotiations on climate change are frequently associated with inaction and the consequences of a perceived disconnection between science and politics. However, our experiences and empirical findings based on research carried out in France in highly diverse situations and among very different operators invalidate this thesis. By analysing climate change from the standpoint of territories and local adaptation and mitigation strategies, our article contends that the problem stems instead from a still insufficient fit between local and global levels of expertise and action frameworks. Moreover, we also need to analyse climate change from a new angle and recognise its dual nature in material and objective terms as well as in its cultural, symbolic and subjective components

  12. Direct Democracy in Local Politics in Denmark

    DEFF Research Database (Denmark)

    Svensson, Palle

    2007-01-01

    Elements of  direct democracy at the local level does exist in Denmark, but it is little known, because no formal rules regulate this aspect of political life, because results from popular initiatives and referendums are not recorded in official statistics, and because few systematic analyses have...... been published. This paper, accordingly, has an explorative nature and asks two basic questions: What is the current state of direct democracy at the local level in Denmark, and what are the prospects for a further development of direct democracy at the local level in Denmark? The paper is based...

  13. Development and verification of local/global analysis techniques for laminated composites

    Science.gov (United States)

    Griffin, O. Hayden, Jr.

    1989-01-01

    Analysis and design methods for laminated composite materials have been the subject of considerable research over the past 20 years, and are currently well developed. In performing the detailed three-dimensional analyses which are often required in proximity to discontinuities, however, analysts often encounter difficulties due to large models. Even with the current availability of powerful computers, models which are too large to run, either from a resource or time standpoint, are often required. There are several approaches which can permit such analyses, including substructuring, use of superelements or transition elements, and the global/local approach. This effort is based on the so-called zoom technique to global/local analysis, where a global analysis is run, with the results of that analysis applied to a smaller region as boundary conditions, in as many iterations as is required to attain an analysis of the desired region. Before beginning the global/local analyses, it was necessary to evaluate the accuracy of the three-dimensional elements currently implemented in the Computational Structural Mechanics (CSM) Testbed. It was also desired to install, using the Experimental Element Capability, a number of displacement formulation elements which have well known behavior when used for analysis of laminated composites.

  14. Selling Academies: Local Democracy and the Management of "Consultation"

    Science.gov (United States)

    Hatcher, Richard

    2008-01-01

    Academies (state schools owned and run by private sponsors on a non-profit basis) are a key element in Labour's education agenda. Proposals to set up Academies, in most cases by taking over existing schools, have provoked local campaigns of opposition in many areas. Replacing a Local Authority with an Academy entails a process of consultation.…

  15. Comparison of subset-based local and FE-based global digital image correlation: Theoretical error analysis and validation

    KAUST Repository

    Pan, B.

    2016-03-22

    Subset-based local and finite-element-based (FE-based) global digital image correlation (DIC) approaches are the two primary image matching algorithms widely used for full-field displacement mapping. Very recently, the performances of these different DIC approaches have been experimentally investigated using numerical and real-world experimental tests. The results have shown that in typical cases, where the subset (element) size is no less than a few pixels and the local deformation within a subset (element) can be well approximated by the adopted shape functions, the subset-based local DIC outperforms FE-based global DIC approaches because the former provides slightly smaller root-mean-square errors and offers much higher computation efficiency. Here we investigate the theoretical origin and lay a solid theoretical basis for the previous comparison. We assume that systematic errors due to imperfect intensity interpolation and undermatched shape functions are negligibly small, and perform a theoretical analysis of the random errors or standard deviation (SD) errors in the displacements measured by two local DIC approaches (i.e., a subset-based local DIC and an element-based local DIC) and two FE-based global DIC approaches (i.e., Q4-DIC and Q8-DIC). The equations that govern the random errors in the displacements measured by these local and global DIC approaches are theoretically derived. The correctness of the theoretically predicted SD errors is validated through numerical translation tests under various noise levels. We demonstrate that the SD errors induced by the Q4-element-based local DIC, the global Q4-DIC and the global Q8-DIC are 4, 1.8-2.2 and 1.2-1.6 times greater, respectively, than that associated with the subset-based local DIC, which is consistent with our conclusions from previous work. © 2016 Elsevier Ltd. All rights reserved.

  16. A study on monitoring methodology for trace elements in the environment through chemical analysis of hair. Part of a coordinated programme on nuclear methods in health-related monitoring of trace element pollutants

    International Nuclear Information System (INIS)

    Fukushima, I.

    1981-06-01

    An attempt was made to monitor community exposure to environmental As, Cd, Cr, Hg, Mn, Pb and Se using hair analysis by instrumental neutron activation analysis and atomic absorption spectroscopy. Hair samples were collected from male and female subjects from six Japanese localities. Samples from each locality were respectively mixed and analysed for elements of interest. The results indicated that this approach was effective in revealing geographical differences of hair elemental levels. The method is suitable for a routine monitoring programme of community exposure to environmental metal pollutants

  17. Higher-order momentum distributions and locally affine LDDMM registration

    DEFF Research Database (Denmark)

    Sommer, Stefan Horst; Nielsen, Mads; Darkner, Sune

    2013-01-01

    description of affine transformations and subsequent compact description of non-translational movement in a globally nonrigid deformation. The resulting representation contains directly interpretable information from both mathematical and modeling perspectives. We develop the mathematical construction......To achieve sparse parametrizations that allow intuitive analysis, we aim to represent deformation with a basis containing interpretable elements, and we wish to use elements that have the description capacity to represent the deformation compactly. To accomplish this, we introduce in this paper...... higher-order momentum distributions in the large deformation diffeomorphic metric mapping (LDDMM) registration framework. While the zeroth-order moments previously used in LDDMM only describe local displacement, the first-order momenta that are proposed here represent a basis that allows local...

  18. Preliminary study of radioactive limonite localities in Colorado, Utah, and Wyoming

    Science.gov (United States)

    Lovering, T.G.; Beroni, E.P.

    1956-01-01

    Nine radioactive limonite localities of different types were sampled during the spring and fall of 1953 in an effort to establish criteria for differentiating limonite outcrops associated with uranium or thorium deposits from limonite outcrops not associated with such deposits. The samples were analyzed for uranium and thorium by standard chemical methods, for equivalent uranium by the radiometric method, and for a number of common metals by semiquantitative geochemical methods. Correlation coefficients were then calculated for each of the metals with respect to equivalent uranium, and to uranium where present, for all of the samples from each locality. The correlation coefficients may indicate a significant association between uranium or thorium and certain metals. Occurrences of specific that are interpreted as significant very considerably for different uranium localities but are more consistent for the thorium localities. Samples taken from radioactive outcrops in the vicinity of uranium or thorium deposits can be quickly analyzed by geochemical methods for various elements. Correlation coefficients can then be determined for the various elements with respect to uranium or thorium; if any significant correlations are obtained, the elements showing such correlation may be indicators of uranium or thorium. Soil samples of covered areas in the vicinity of the radioactive outcrop may then be analyzed for the indicator elements and any resulting anomalies used as a guide for prospecting where the depth of overburden is too great to allow the use of radiation-detecting instruments. Correlation coefficients of the associated indicator elements, used in conjunction with petrographic evidence, may also be useful in interpreting the origin and paragenesis of radioactive deposits. Changes in color of limonite stains on the outcrop may also be a useful guide to ore in some areas.

  19. Pure state consciousness and its local reduction to neuronal space

    Science.gov (United States)

    Duggins, A. J.

    2013-01-01

    The single neuronal state can be represented as a vector in a complex space, spanned by an orthonormal basis of integer spike counts. In this model a scalar element of experience is associated with the instantaneous firing rate of a single sensory neuron over repeated stimulus presentations. Here the model is extended to composite neural systems that are tensor products of single neuronal vector spaces. Depiction of the mental state as a vector on this tensor product space is intended to capture the unity of consciousness. The density operator is introduced as its local reduction to the single neuron level, from which the firing rate can again be derived as the objective correlate of a subjective element. However, the relational structure of perceptual experience only emerges when the non-local mental state is considered. A metric of phenomenal proximity between neuronal elements of experience is proposed, based on the cross-correlation function of neurophysiology, but constrained by the association of theoretical extremes of correlation/anticorrelation in inseparable 2-neuron states with identical and opponent elements respectively.

  20. 高校图书馆不同功能定位下对音乐元素运用的思考%Considerations about the Application of Musical Elements under Different Functional Localizations of University Library

    Institute of Scientific and Technical Information of China (English)

    陈艳艳

    2015-01-01

    在高校图书馆传统功能定位下,音乐元素的融入受到了极大的限制。音乐及阅读心理治疗等新功能的设置,则将音乐元素更广、更深地融入到高校图书馆的工作中,可更好地为高校广大师生的学习生活提供服务。从高校图书馆传统功能定位下音乐元素的融入和高校图书馆新功能定位下音乐元素的融入两个方面,提出了高校图书馆不同功能定位下对音乐元素运用的思考。%ABSTRACT:Under university library’s traditional functional localization, the integration of musical element is greatly limited. And the setting of new functions such as the music, and reading therapy, etc. integrates the musical elements into the work of university library in a broader and deeper way, which can provide better services for the study and life of university’s teachers and students. This paper considers the application of the music elements under university library’s traditional functional localization and under university library’s new functional localization.

  1. Micro-scale spatial expansion of microbial cells and mobile genetic elements

    DEFF Research Database (Denmark)

    Smets, Barth F.; Kreft, Jan-Ulrich; Or, Dani

    Microbes can actively explore their local spatial environment when sufficiently hydrated pathways are present - mobile gene elements can also travel in local environments when cellular density is sufficient. In this presentation, I will present our efforts at predicting the dynamics of these two...... processes, and how they are affected by physical and biological constraints, using spatially-explicit agent-based models....

  2. Ecopedagogy as an element of citizenship education: The dialectic of global/local spheres of citizenship and critical environmental pedagogies

    Science.gov (United States)

    Misiaszek, Greg William

    2016-10-01

    Emerging from popular education movements in Latin America, ecopedagogy is a critical environmental pedagogy which focuses on understanding the connections between social conflict and environmentally harmful acts carried out by humans. These connections are often politically hidden in education. Ecopedagogy, while being pluralistic, is in its essence defined as a critical, transformative environmental pedagogy centred on increasing social and environmental justice. Its ultimate aim is to find a sustainable balance between the conflicting goals of diverse notions of human progress and environmental wellbeing. This article is based on two comparative research projects. The first was a qualitative study on ecopedagogical models involving 31 expert ecopedagogues in Argentina, Brazil and the Appalachian region of the United States. They were asked for their perspectives on how successful ecopedagogy can be defined within the contexts in which they taught and conducted research. The second study analysed how 18 international expert scholars of citizenship and/or environmental pedagogy from six world continents regarded the ways in which citizenship intersects with environmental issues and the pedagogies of both in an increasingly globalised world, with specific focus on Global Citizenship Education. Results from the first study indicate the following two needs for effective environmental pedagogies: (1) for there to be an ecopedagogical paradigm shift in environmental teaching and research; and (2) for ecopedagogy to be an essential element of citizenship education (and vice versa). This article examines how conflicting processes of globalisation both help and hinder in achieving such a paradigm shift by decentring traditional nation-state citizenship. Results from the second study indicate how critical teaching within and between different spheres of citizenship (e.g. local, national, global, and planetary citizenship) is essential for ecopedagogy (and the

  3. Duration judgements over multiple elements

    Directory of Open Access Journals (Sweden)

    Inci eAyhan

    2012-11-01

    Full Text Available We investigated the limits of the number of events observers can simultaneously time. For single targets occurring in one of eight positions sensitivity to duration was improved for spatially pre-cued items as compared to post-cued items indicating that exogenous driven attention can improve duration discrimination. Sensitivity to duration for pre-cued items was also marginally better for single items as compared to eight items indicating that even after the allocation of focal attention, distracter items can interfere with the encoding of duration. For an eight item array discrimination was worse for post-cued locations as compared to pre-cued locations indicating both that attention can improve duration discrimination performance and that it was not possible to access a perfect memory trace of the duration of eight elements. The interference from the distracters in the pre-cued eight item array may reflect some mandatory averaging of target and distracter events. To further explore duration averaging we asked subjects to explicitly compare average durations of multiple item arrays against a single item standard duration. Duration discrimination thresholds were significantly lower for single elements as compared to multiple elements, showing that averaging, either automatically or intentionally, impairs duration discrimination. There was no set size effect. Performance was the same for averages of two and eight items, but performance with even an average of two items was worse than for one item. This was also true for sequential presentation indicating poor performance was not due to limits on the division of attention across items. Rather performance appears to be limited by an inability to remember or aggregate duration information from two or more items. Although it is possible to manipulate perceived duration locally, there appears to be no perceptual mechanisms for aggregating local durations across space.

  4. Trace element distribution in geochemical environment of the island Krk and its influence on the local population

    International Nuclear Information System (INIS)

    Kutle, A.; Orescanin, V.; Obhodas, J.; Valkovic, V.

    2004-01-01

    Samples of soil, plant material and water collected on the Croatian island Krk in northern Adriatic sea were analyzed for a number of elements (Ca, Ti, Mn, Fe, Ni, Cu, Zn, As, Br, Rb, Sr, Zr, Pb) by using energy dispersive X-ray fluorescence (EDXRF) as an analytical tool. Some of these data have been previously used to produce geochemical map of the island. In addition, trace element contents of hair from children, attending elementary and secondary schools, has been investigated using the same analytical method for Mg, S, Ca, Cr, Mn, Fe, Ni, Cu, Zn, As, Hg and Pb elements. Concentrations of the twelve elements and nine variables from the questionnaire, i.e., age, sex, living place, transportation, medication, hair colour, hair type, type of shampoo used and hair treatment, were considered in the statistical analysis. The observed differences for the seven island's communes have also been discussed. (author)

  5. College Binge Drinking Associated with Decreased Frontal Activation to Negative Emotional Distractors during Inhibitory Control

    Directory of Open Access Journals (Sweden)

    Julia E. Cohen-Gilbert

    2017-09-01

    Full Text Available The transition to college is associated with an increase in heavy episodic alcohol use, or binge drinking, during a time when the prefrontal cortex and prefrontal-limbic circuitry continue to mature. Traits associated with this immaturity, including impulsivity in emotional contexts, may contribute to risky and heavy episodic alcohol consumption. The current study used blood oxygen level dependent (BOLD multiband functional magnetic resonance imaging (fMRI to assess brain activation during a task that required participants to ignore background images with positive, negative, or neutral emotional valence while performing an inhibitory control task (Go-NoGo. Subjects were 23 college freshmen (seven male, 18–20 years who engaged in a range of drinking behavior (past 3 months’ binge episodes range = 0–19, mean = 4.6, total drinks consumed range = 0–104, mean = 32.0. Brain activation on inhibitory trials (NoGo was contrasted between negative and neutral conditions and between positive and neutral conditions using non-parametric testing (5000 permutations and cluster-based thresholding (z = 2.3, p ≤ 0.05 corrected. Results showed that a higher recent incidence of binge drinking was significantly associated with decreased activation of dorsolateral prefrontal cortex (DLPFC, dorsomedial prefrontal cortex (DMPFC, and anterior cingulate cortex (ACC, brain regions strongly implicated in executive functioning, during negative relative to neutral inhibitory trials. No significant associations between binge drinking and brain activation were observed for positive relative to neutral images. While task performance was not significantly associated with binge drinking in this sample, subjects with heavier recent binge drinking showed decreased recruitment of executive control regions under negative versus neutral distractor conditions. These findings suggest that in young adults with heavier recent binge drinking, processing of negative emotional

  6. Origin and Evolution of the Elements

    Science.gov (United States)

    McWilliam, Andrew; Rauch, Michael

    2004-09-01

    Introduction; List of participants; 1. Mount Wilson Observatory contributions to the study of cosmic abundances of the chemical elements George W. Preston; 2. Synthesis of the elements in stars: B2FH and beyond E. Margaret Burbidge; 3. Stellar nucleosynthesis: a status report 2003 David Arnett; 4. Advances in r-process nucleosynthesis John J. Cowan and Christopher Sneden; 5. Element yields of intermediate-mass stars Richard B. C. Henry; 6. The impact of rotation on chemical abundances in red giant branch stars Corinne Charbonnel; 7. s-processing in AGB stars and the composition of carbon stars Maurizio Busso, Oscar Straniero, Roberto Gallino, and Carlos Abia; 8. Models of chemical evolution Francesca Matteucci; 9. Model atmospheres and stellar abundance analysis Bengt Gustafsson; 10. The light elements: lithium, beryllium, and boron Ann Merchant Boesgaard; 11. Extremely metal-poor stars John E. Norris; 12. Thin and thick galactic disks Poul E. Nissen; 13. Globular clusters and halo field stars Christopher Sneden, Inese I. Ivans and Jon P. Fulbright; 14. Chemical evolution in ω Centauri Verne V. Smith; 15. Chemical composition of the Magellanic Clouds, from young to old stars Vanessa Hill; 16. Detailed composition of stars in dwarf spheroidal galaxies Matthew D. Shetrone; 17. The evolutionary history of Local Group irregular galaxies Eva K. Grebel; 18. Chemical evolution of the old stellar populations of M31 R. Michael Rich; 19. Stellar winds of hot massive stars nearby and beyond the Local Group Fabio Bresolin and Rolf P. Kudritzki; 20. Presolar stardust grains Donald D. Clayton and Larry R. Nittler; 21. Interstellar dust B. T. Draine; 22. Interstellar atomic abundances Edward B. Jenkins; 23. Molecules in the interstellar medium Tommy Wiklind; 24. Metal ejection by galactic winds Crystal L. Martin; 25. Abundances from the integrated light of globular clusters and galaxies Scott C. Trager; 26. Abundances in spiral and irregular galaxies Donald R. Garnett; 27

  7. Inhibition in movement plan competition: reach trajectories curve away from remembered and task-irrelevant present but not from task-irrelevant past visual stimuli.

    Science.gov (United States)

    Moehler, Tobias; Fiehler, Katja

    2017-11-01

    The current study investigated the role of automatic encoding and maintenance of remembered, past, and present visual distractors for reach movement planning. The previous research on eye movements showed that saccades curve away from locations actively kept in working memory and also from task-irrelevant perceptually present visual distractors, but not from task-irrelevant past distractors. Curvature away has been associated with an inhibitory mechanism resolving the competition between multiple active movement plans. Here, we examined whether reach movements underlie a similar inhibitory mechanism and thus show systematic modulation of reach trajectories when the location of a previously presented distractor has to be (a) maintained in working memory or (b) ignored, or (c) when the distractor is perceptually present. Participants performed vertical reach movements on a computer monitor from a home to a target location. Distractors appeared laterally and near or far from the target (equidistant from central fixation). We found that reaches curved away from the distractors located close to the target when the distractor location had to be memorized and when it was perceptually present, but not when the past distractor had to be ignored. Our findings suggest that automatically encoding present distractors and actively maintaining the location of past distractors in working memory evoke a similar response competition resolved by inhibition, as has been previously shown for saccadic eye movements.

  8. Two-loop operator matrix elements for massive fermionic local twist-2 operators in QED

    International Nuclear Information System (INIS)

    Bluemlein, J.; Freitas, A. de; Universidad Simon Bolivar, Caracas; Neerven, W.L. van

    2011-11-01

    We describe the calculation of the two--loop massive operator matrix elements with massive external fermions in QED. We investigate the factorization of the O(α 2 ) initial state corrections to e + e - annihilation into a virtual boson for large cms energies s >>m 2 e into massive operator matrix elements and the massless Wilson coefficients of the Drell-Yan process adapting the color coefficients to the case of QED, as proposed by F. A. Berends et. al. (Nucl. Phys. B 297 (1988)429). Our calculations show explicitly that the representation proposed there works at one-loop order and up to terms linear in ln (s/m 2 e ) at two-loop order. However, the two-loop constant part contains a few structural terms, which have not been obtained in previous direct calculations. (orig.)

  9. Construction of extremal local positive-operator-valued measures under symmetry

    International Nuclear Information System (INIS)

    Virmani, S.; Plenio, M.B.

    2003-01-01

    We study the local implementation of positive-operator-valued measures (POVMs) when we require only the faithful reproduction of the statistics of the measurement outcomes for all initial states. We first demonstrate that any POVM with separable elements can be implemented by a separable superoperator, and develop techniques for calculating the extreme points of POVMs under a certain class of constraint that includes separability and positive partial transposition. As examples we consider measurements that are invariant under various symmetry groups (Werner, isotropic, Bell diagonal, local orthogonal), and demonstrate that in these cases separability of the POVM elements is equivalent to implementability via local operations and classical communication (LOCC). We also calculate the extrema of these classes of measurement under the groups that we consider, and give explicit LOCC protocols for attaining them. These protocols are hence optimal methods for locally discriminating between states of these symmetries. One of many interesting consequences is that the best way to locally discriminate Bell-diagonal mixed states is to perform a two-outcome POVM using local von Neumann projections. This is true regardless of the cost function, the number of states being discriminated, or the prior probabilities. Our results give the first cases of local mixed-state discrimination that can be analyzed quantitatively in full, and may have application to other problems such as demonstrations of nonlocality, experimental entanglement witnesses, and perhaps even entanglement distillation

  10. Role of nuclear analytical probe techniques in biological trace element research

    International Nuclear Information System (INIS)

    Jones, K.W.; Pounds, J.G.

    1985-01-01

    Many biomedical experiments require the qualitative and quantitative localization of trace elements with high sensitivity and good spatial resolution. The feasibility of measuring the chemical form of the elements, the time course of trace elements metabolism, and of conducting experiments in living biological systems are also important requirements for biological trace element research. Nuclear analytical techniques that employ ion or photon beams have grown in importance in the past decade and have led to several new experimental approaches. Some of the important features of these methods are reviewed here along with their role in trace element research, and examples of their use are given to illustrate potential for new research directions. It is emphasized that the effective application of these methods necessitates a closely integrated multidisciplinary scientific team. 21 refs., 4 figs., 1 tab

  11. Levels of major and trace elements, including rare earth elements, and ²³⁸U in Croatian tap waters.

    Science.gov (United States)

    Fiket, Željka; Rožmarić, Martina; Krmpotić, Matea; Benedik, Ljudmila

    2015-05-01

    Concentrations of 46 elements, including major, trace, and rare earth elements, and (238)U in Croatian tap waters were investigated. Selected sampling locations include tap waters from various hydrogeological regions, i.e., different types of aquifers, providing insight into the range of concentrations of studied elements and (238)U activity concentrations in Croatian tap waters. Obtained concentrations were compared with the Croatian maximum contaminant levels for trace elements in water intended for human consumption, as well as WHO and EPA drinking water standards. Concentrations in all analyzed tap waters were found in accordance with Croatian regulations, except tap water from Šibenik in which manganese in concentration above maximum permissible concentration (MPC) was measured. Furthermore, in tap water from Osijek, levels of arsenic exceeded the WHO guidelines and EPA regulations. In general, investigated tap waters were found to vary considerably in concentrations of studied elements, including (238)U activity concentrations. Causes of variability were further explored using statistical methods. Composition of studied tap waters was found to be predominately influenced by hydrogeological characteristics of the aquifer, at regional and local level, the existing redox conditions, and the household plumbing system. Rare earth element data, including abundances and fractionation patterns, complemented the characterization and facilitated the interpretation of factors affecting the composition of the analyzed tap waters.

  12. Golgi bypass for local delivery of axonal proteins, fact or fiction?

    Science.gov (United States)

    González, Carolina; Cornejo, Víctor Hugo; Couve, Andrés

    2018-04-06

    Although translation of cytosolic proteins is well described in axons, much less is known about the synthesis, processing and trafficking of transmembrane and secreted proteins. A canonical rough endoplasmic reticulum or a stacked Golgi apparatus has not been detected in axons, generating doubts about the functionality of a local route. However, axons contain mRNAs for membrane and secreted proteins, translation factors, ribosomal components, smooth endoplasmic reticulum and post-endoplasmic reticulum elements that may contribute to local biosynthesis and plasma membrane delivery. Here we consider the evidence supporting a local secretory system in axons. We discuss exocytic elements and examples of autonomous axonal trafficking that impact development and maintenance. We also examine whether unconventional post-endoplasmic reticulum pathways may replace the canonical Golgi apparatus. Copyright © 2018. Published by Elsevier Ltd.

  13. Permittivity disorder induced Anderson localization in magnetophotonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Abdi-Ghaleh, R., E-mail: r.abdi@bonabu.ac.ir [Department of Laser and Optical Engineering, University of Bonab, 5551761167 Bonab (Iran, Islamic Republic of); Namdar, A. [Faculty of Physics, University of Tabriz, 5166614766 Tabriz (Iran, Islamic Republic of)

    2016-11-15

    This theoretical study was carried out to investigate the permittivity disorder induced Anderson localization of light in one-dimensional magnetophotonic crystals. It was shown that the disorder create the resonant transmittance modes associated with enhanced Faraday rotations inside the photonic band gap. The average localization length of the right- and left-handed circular polarizations (RCP and LCP), the total transmittance together with the ensemble average of the RCP and LCP phases, and the Faraday rotation of the structure were also investigated. For this purpose, the off-diagonal elements of the permittivity tensor were varied for various wavelengths of incident light. The obtained results revealed the nonreciprocal property of circular eigen modes. This study can potentially open up a new aspect for utilizing the disorder magnetophotonic structures in nonreciprocal systems such as isolators and circulators. - Highlights: • We theoretically investigated the permittivity disorder induced Anderson localization of light in magnetophotonic crystals. • The disorder considered in the diagonal elements of the permittivity tensor of magneto-optical layers. • The disorder create the resonant transmittance modes associated with enhanced Faraday rotations in the photonic band gap. • The average localization length of the circular polarizations and the ensemble average of their phases were investigated. • The obtained results revealed the nonreciprocal property of circular eigen modes.

  14. Statistical equilibrium equations for trace elements in stellar atmospheres

    OpenAIRE

    Kubat, Jiri

    2010-01-01

    The conditions of thermodynamic equilibrium, local thermodynamic equilibrium, and statistical equilibrium are discussed in detail. The equations of statistical equilibrium and the supplementary equations are shown together with the expressions for radiative and collisional rates with the emphasize on the solution for trace elements.

  15. Noise source localization on tyres using an inverse boundary element method

    DEFF Research Database (Denmark)

    Schuhmacher, Andreas; Saemann, E-U; Hald, J

    1998-01-01

    A dominating part of tyre noise is radiated from a region close to the tyre/road contact patch, where it is very difficult to measure both the tyre vibration and the acoustic near field. The approach taken in the present paper is to model the tyre and road surfaces with a Boundary Element Model...... (BEM), with unknown node vibration data on the tyre surface. The BEM model is used to calculate a set of transfer functions from the node vibrations to the sound pressure at a set of microphone positions around the tyre. By approximate inversion of the matrix of transfer functions, the surface...... from tyre noise measurements will be presented at the conference....

  16. Advanced solid elements for sheet metal forming simulation

    Science.gov (United States)

    Mataix, Vicente; Rossi, Riccardo; Oñate, Eugenio; Flores, Fernando G.

    2016-08-01

    The solid-shells are an attractive kind of element for the simulation of forming processes, due to the fact that any kind of generic 3D constitutive law can be employed without any additional hypothesis. The present work consists in the improvement of a triangular prism solid-shell originally developed by Flores[2, 3]. The solid-shell can be used in the analysis of thin/thick shell, undergoing large deformations. The element is formulated in total Lagrangian formulation, and employs the neighbour (adjacent) elements to perform a local patch to enrich the displacement field. In the original formulation a modified right Cauchy-Green deformation tensor (C) is obtained; in the present work a modified deformation gradient (F) is obtained, which allows to generalise the methodology and allows to employ the Pull-Back and Push-Forwards operations. The element is based in three modifications: (a) a classical assumed strain approach for transverse shear strains (b) an assumed strain approach for the in-plane components using information from neighbour elements and (c) an averaging of the volumetric strain over the element. The objective is to use this type of elements for the simulation of shells avoiding transverse shear locking, improving the membrane behaviour of the in-plane triangle and to handle quasi-incompressible materials or materials with isochoric plastic flow.

  17. Two gamma-ray detectors method for examination of fuel elements

    International Nuclear Information System (INIS)

    Kristof, E.; Pregl, G.

    1979-01-01

    Th initial experiment and method for the nondestructive determination of a fuel element burnup is given. The method eliminates the error which originates from the unknown local dependency of the attenuation coefficient for gamma rays in fuel. (author)

  18. Reduced Distractibility in a Remote Culture

    Science.gov (United States)

    de Fockert, Jan W.; Caparos, Serge; Linnell, Karina J.; Davidoff, Jules

    2011-01-01

    Background In visual processing, there are marked cultural differences in the tendency to adopt either a global or local processing style. A remote culture (the Himba) has recently been reported to have a greater local bias in visual processing than Westerners. Here we give the first evidence that a greater, and remarkable, attentional selectivity provides the basis for this local bias. Methodology/Principal Findings In Experiment 1, Eriksen-type flanker interference was measured in the Himba and in Western controls. In both groups, responses to the direction of a task-relevant target arrow were affected by the compatibility of task-irrelevant distractor arrows. However, the Himba showed a marked reduction in overall flanker interference compared to Westerners. The smaller interference effect in the Himba occurred despite their overall slower performance than Westerners, and was evident even at a low level of perceptual load of the displays. In Experiment 2, the attentional selectivity of the Himba was further demonstrated by showing that their attention was not even captured by a moving singleton distractor. Conclusions/Significance We argue that the reduced distractibility in the Himba is clearly consistent with their tendency to prioritize the analysis of local details in visual processing. PMID:22046275

  19. Keynesian Substantiation of the Marketing Policies in Local Development

    Directory of Open Access Journals (Sweden)

    Lucica MATEI

    2010-06-01

    Full Text Available The local development means the existence of several goods and services and their performance, expressed through adequate marketing policies, thus determining the overall development performance.The paper approaches the economic fundamental issues of local development and in this context it determines the basic components of public service marketing, relevant for local development: price, multiplier of revenues/expenditures, respectively the export multiplier.Those elements will express the ratios between resources and outcomes and their balance is based on a Keynesian model in an open economy.

  20. Salleles wind-farm: local residents' opinion; Parc de Salleles: l'avis des riverains

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2000-06-01

    This article presents a survey that has been led to study the acceptability of wind turbines by local populations. 11 families living in the neighbourhood of the Salleles wind farm (near Carcassonne, France) have been interviewed. A few recommendations can be drawn from this survey. It is necessary to organize information campaigns in order to make people consider wind farms as elements of the local economy. As for site choice any already visually polluted area should be barred, for wind turbines might be seen more as a supplementary negative element than as a positive element aimed at counterbalancing a dissatisfying situation. (A.C.)

  1. Generalized multiscale finite element method. Symmetric interior penalty coupling

    KAUST Repository

    Efendiev, Yalchin R.; Galvis, Juan; Lazarov, Raytcho D.; Moon, M.; Sarkis, Marcus V.

    2013-01-01

    Motivated by applications to numerical simulations of flows in highly heterogeneous porous media, we develop multiscale finite element methods for second order elliptic equations. We discuss a multiscale model reduction technique in the framework of the discontinuous Galerkin finite element method. We propose two different finite element spaces on the coarse mesh. The first space is based on a local eigenvalue problem that uses an interior weighted L2-norm and a boundary weighted L2-norm for computing the "mass" matrix. The second choice is based on generation of a snapshot space and subsequent selection of a subspace of a reduced dimension. The approximation with these multiscale spaces is based on the discontinuous Galerkin finite element method framework. We investigate the stability and derive error estimates for the methods and further experimentally study their performance on a representative number of numerical examples. © 2013 Elsevier Inc.

  2. Generalized multiscale finite element method. Symmetric interior penalty coupling

    KAUST Repository

    Efendiev, Yalchin R.

    2013-12-01

    Motivated by applications to numerical simulations of flows in highly heterogeneous porous media, we develop multiscale finite element methods for second order elliptic equations. We discuss a multiscale model reduction technique in the framework of the discontinuous Galerkin finite element method. We propose two different finite element spaces on the coarse mesh. The first space is based on a local eigenvalue problem that uses an interior weighted L2-norm and a boundary weighted L2-norm for computing the "mass" matrix. The second choice is based on generation of a snapshot space and subsequent selection of a subspace of a reduced dimension. The approximation with these multiscale spaces is based on the discontinuous Galerkin finite element method framework. We investigate the stability and derive error estimates for the methods and further experimentally study their performance on a representative number of numerical examples. © 2013 Elsevier Inc.

  3. Calculation methods' comparative analysis of monorail hoist crane local bending effects

    Directory of Open Access Journals (Sweden)

    Cvijović Goran M.

    2016-01-01

    Full Text Available The results of numerical and experimental researches of local bending problems, carried on classic and medium-wide I profiles, were a basis for the adoption of the current standards (EN 15011: 2014 which regulates the action of the local stress caused by the effect of cart wheels. Regarding the fact that IPB (HE-B wide flange profiles are largely used for production of the main carriers of monorail transport systems, this paper presents the results of the action of the local stress caused by the effect of cart wheels on the HE-A flange profile, using the methods and procedures of relevant researchers, the procedures prescribed by the standard EN 15011 as well as the results of calculations using finite element method. It has been revealed, based on comparative analysis of the results, that in the transition zone low flange / rib longitudinal local stress on the lower contour flange, determined using the above mentioned standards have tightening characteristic, while all other methods, including finite element method, give the pressing nature of the considered voltage. In addition, all of these procedures, except for the finite element method, adopt the assumption that absolute value of voltage, caused by local bending on upper and lower contour of the loaded flange, are the same, and there is no physical justification. Bearing in mind the fact that stress identification, caused by the flange local bending, is an extremely important phase proving the strength of monorail beams, we may conclude that the application of standard EN 15011 does not provide reliable results when it comes to wide flange profiles.

  4. SHAPE FROM TEXTURE USING LOCALLY SCALED POINT PROCESSES

    Directory of Open Access Journals (Sweden)

    Eva-Maria Didden

    2015-09-01

    Full Text Available Shape from texture refers to the extraction of 3D information from 2D images with irregular texture. This paper introduces a statistical framework to learn shape from texture where convex texture elements in a 2D image are represented through a point process. In a first step, the 2D image is preprocessed to generate a probability map corresponding to an estimate of the unnormalized intensity of the latent point process underlying the texture elements. The latent point process is subsequently inferred from the probability map in a non-parametric, model free manner. Finally, the 3D information is extracted from the point pattern by applying a locally scaled point process model where the local scaling function represents the deformation caused by the projection of a 3D surface onto a 2D image.

  5. Local versus global interactions in nonequilibrium transitions: A model of social dynamics

    Science.gov (United States)

    González-Avella, J. C.; Eguíluz, V. M.; Cosenza, M. G.; Klemm, K.; Herrera, J. L.; San Miguel, M.

    2006-04-01

    A nonequilibrium system of locally interacting elements in a lattice with an absorbing order-disorder phase transition is studied under the effect of additional interacting fields. These fields are shown to produce interesting effects in the collective behavior of this system. Both for autonomous and external fields, disorder grows in the system when the probability of the elements to interact with the field is increased. There exists a threshold value of this probability beyond which the system is always disordered. The domain of parameters of the ordered regime is larger for nonuniform local fields than for spatially uniform fields. However, the zero field limit is discontinous. In the limit of vanishingly small probability of interaction with the field, autonomous or external fields are able to order a system that would fall in a disordered phase under local interactions of the elements alone. We consider different types of fields which are interpreted as forms of mass media acting on a social system in the context of Axelrod’s model for cultural dissemination.

  6. Finite-volume effects due to spatially non-local operators arXiv

    CERN Document Server

    Briceño, Raúl A.; Hansen, Maxwell T.; Monahan, Christopher J.

    Spatially non-local matrix elements are useful lattice-QCD observables in a variety of contexts, for example in determining hadron structure. To quote credible estimates of the systematic uncertainties in these calculations, one must understand, among other things, the size of the finite-volume effects when such matrix elements are extracted from numerical lattice calculations. In this work, we estimate finite-volume effects for matrix elements of non-local operators, composed of two currents displaced in a spatial direction by a distance $\\xi$. We find that the finite-volume corrections depend on the details of the matrix element. If the external state is the lightest degree of freedom in the theory, e.g.~the pion in QCD, then the volume corrections scale as $ e^{-m_\\pi (L- \\xi)} $, where $m_\\pi$ is the mass of the light state. For heavier external states the usual $e^{- m_\\pi L}$ form is recovered, but with a polynomial prefactor of the form $L^m/|L - \\xi|^n$ that can lead to enhanced volume effects. These ...

  7. Wake Instabilities Behind Discrete Roughness Elements in High Speed Boundary Layers

    Science.gov (United States)

    Choudhari, Meelan; Li, Fei; Chang, Chau-Lyan; Norris, Andrew; Edwards, Jack

    2013-01-01

    Computations are performed to study the flow past an isolated, spanwise symmetric roughness element in zero pressure gradient boundary layers at Mach 3.5 and 5.9, with an emphasis on roughness heights of less than 55 percent of the local boundary layer thickness. The Mach 5.9 cases include flow conditions that are relevant to both ground facility experiments and high altitude flight ("cold wall" case). Regardless of the Mach number, the mean flow distortion due to the roughness element is characterized by long-lived streamwise streaks in the roughness wake, which can support instability modes that did not exist in the absence of the roughness element. The higher Mach number cases reveal a variety of instability mode shapes with velocity fluctuations concentrated in different localized regions of high base flow shear. The high shear regions vary from the top of a mushroom shaped structure characterizing the centerline streak to regions that are concentrated on the sides of the mushroom. Unlike the Mach 3.5 case with nearly same values of scaled roughness height k/delta and roughness height Reynolds number Re(sub kk), the odd wake modes in both Mach 5.9 cases are significantly more unstable than the even modes of instability. Additional computations for a Mach 3.5 boundary layer indicate that the presence of a roughness element can also enhance the amplification of first mode instabilities incident from upstream. Interactions between multiple roughness elements aligned along the flow direction are also explored.

  8. Gift from statistical learning: Visual statistical learning enhances memory for sequence elements and impairs memory for items that disrupt regularities.

    Science.gov (United States)

    Otsuka, Sachio; Saiki, Jun

    2016-02-01

    Prior studies have shown that visual statistical learning (VSL) enhances familiarity (a type of memory) of sequences. How do statistical regularities influence the processing of each triplet element and inserted distractors that disrupt the regularity? Given that increased attention to triplets induced by VSL and inhibition of unattended triplets, we predicted that VSL would promote memory for each triplet constituent, and degrade memory for inserted stimuli. Across the first two experiments, we found that objects from structured sequences were more likely to be remembered than objects from random sequences, and that letters (Experiment 1) or objects (Experiment 2) inserted into structured sequences were less likely to be remembered than those inserted into random sequences. In the subsequent two experiments, we examined an alternative account for our results, whereby the difference in memory for inserted items between structured and random conditions is due to individuation of items within random sequences. Our findings replicated even when control letters (Experiment 3A) or objects (Experiment 3B) were presented before or after, rather than inserted into, random sequences. Our findings suggest that statistical learning enhances memory for each item in a regular set and impairs memory for items that disrupt the regularity. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Rock’n’Roll as a Local Musical Phenomenon

    Directory of Open Access Journals (Sweden)

    Marija Ristivojević

    2016-02-01

    Full Text Available The paper considers the process of localization of a pop cultural and musical phenomenon – rock ’n’ roll. My basic premise is that rock ’n’ roll as a global music genre can be perceived as local, and hence represents a recognizable identification element for the local population. In this case the label r ’n’ r pertain to the phenomenon of Belgrade "new wave" music, which was popular during the 1980’s. Based on the analysis of narratives from relevant documentary films, it is my intention to find out whether "new wave" was initially perceived as a local phenomenon, and what the means of constructing this image are, as well as what it is that gives this phenomenon local legitimacy and credibility.

  10. GOVERNANCE FROM BELOW A Theory of Local Government With Two Empirical Tests

    OpenAIRE

    Jean-Paul Faguet

    2005-01-01

    I examine decentralization through the lens of the local dynamics that it unleashes. The national effects of decentralization are simply the sum of its local-level effects. Hence to understand decentralization we must first understand how local government works. This paper proposes a theory of local government as the confluence of two quasi-markets and one organizational dynamic. Good government results when these three elements - political, economic and civil - are in rough balance, and acto...

  11. Protective systems and its protective switching elements on local failures of large slow-capacitor bank system

    International Nuclear Information System (INIS)

    Hasegawa, Mitsuo; Inoue, Kunikazu; Ueno, Isao.

    1994-01-01

    In various applications of pulsed power technologies, large capacitor bank systems are used to feed high current impulse to different experimental devices. The accidental electric breakdown in one of the capacitors in a parallel connection of the large bank may result in serious damages such as mechanical explosion and oil effusion or fire. In most fast banks, each unit capacitor has an output gap switch, which is expected to decouple the capacitors one another. However, no such special element is adopted usually in the slow bank system, partly because of the economical consideration. We have developed a novel and inexpensive protective element for these relatively slow capacitor banks, utilizing a concept of the enclosed type of the fast breakers. The principle of the operation of the protection elements is verified by a simulation experiment. Their practical effectiveness is also successfully demonstrated in the application to the system of the pulsed high magnetic field generator. (author)

  12. Steepest descent method for set-valued locally accretive mappings

    International Nuclear Information System (INIS)

    Chidume, C.E.

    1993-05-01

    Let E be a real q-uniformly smooth Banach space. Suppose T is a set-valued locally strongly accretive map with open domain D(T) in E and that 0 is an element of Tx has a solution x* in D(T). Then there exists a neighbourhood B in D(T) of x* and a real number r 1 >0 such that for any r>r 1 and some real sequence {c n }, any initial guess x 1 is an element of B and any single-valued selection T 0 of T, the sequence {x n } generated from x 1 by x n+1 =x n -c n T 0 x n , n≥1, remains in D(T) and converges strongly to x* with ||x n -x*|| O(n -(q-1)/ q). A related result deals with iterative approximation of a solution of the equation f is an element of x+Ax when A is a locally accretive map. Our theorems generalize important known results and resolve a problem of interest. (author). 39 refs

  13. Industry and agriculture: Elements of the economic profile of Kladovo municipality

    Directory of Open Access Journals (Sweden)

    Miletić Radmila

    2006-01-01

    Full Text Available On the basis of spatial differentiation of the natural and socio-economic factors of development, we have seen the structural characteristics of the local industry and local agriculture, as two elements of the economy of Kladovo municipality, and the importance and role of these two elements in the spatial structure of the municipality. Particular attention was devoted in the course of this research, to the possibilities of intensifying the development of the less developed parts of the area. Activation of developmental potentials is directed towards a demographic revitalization and towards the establishment of a stable and progressive social-economic-ecological area, with an identity recognizable in the region. In that sense, we examine the inter-dependence of potentials limitations and risks for a more rapid future development of the municipality of Kladovo.

  14. Study of trace elements in milk by nuclear analytical techniques

    International Nuclear Information System (INIS)

    Gharib, A.; Rahimi, H.; Pyrovan, H.; Raoffi, N.J.; Taherpoor, H.

    1985-01-01

    This work is part of project with the IAEA in a coordinated program on 'Trace Elements in Human and Bio-environmental Systems' to evaluate their nutritional requierements, interrelations and the role of trace elements in health, metabolism, etc. Cow's milk is regarded to be one of the most important and most nutritious foodstuffs of mankind. Hence, as a first step, an elemental analysis for milk was carried out: a few samples of pasteurized milk and local samples were investigated for essential and toxic trace elements. The secondary aim of the project was the assessment of various analytical techniques involved. AAS, PIXE and NAA are presented here. The latter was applied both instrumentally and radiochemically. Although the results pertaining to the various methods employed are not in good agreement, there is, however, some justification to clarify this internal inconsistency. PIXE analysis is very fast and rather routine, but the technique for trace element analysis needs certain adaptations and improvement. (author)

  15. Global/local methods for probabilistic structural analysis

    Science.gov (United States)

    Millwater, H. R.; Wu, Y.-T.

    1993-04-01

    A probabilistic global/local method is proposed to reduce the computational requirements of probabilistic structural analysis. A coarser global model is used for most of the computations with a local more refined model used only at key probabilistic conditions. The global model is used to establish the cumulative distribution function (cdf) and the Most Probable Point (MPP). The local model then uses the predicted MPP to adjust the cdf value. The global/local method is used within the advanced mean value probabilistic algorithm. The local model can be more refined with respect to the g1obal model in terms of finer mesh, smaller time step, tighter tolerances, etc. and can be used with linear or nonlinear models. The basis for this approach is described in terms of the correlation between the global and local models which can be estimated from the global and local MPPs. A numerical example is presented using the NESSUS probabilistic structural analysis program with the finite element method used for the structural modeling. The results clearly indicate a significant computer savings with minimal loss in accuracy.

  16. Improved nuclear fuel element

    International Nuclear Information System (INIS)

    1980-01-01

    The invention is of a nuclear fuel element which comprises a central core of a body of nuclear fuel material selected from the group consisting of compounds of uranium, plutonium, thorium and mixtures thereof, and an elongated composite cladding container comprising a zirconium alloy tube containing constituents other than zirconium in an amount greater than about 5000 parts per million by weight and an undeformed metal barrier of moderate purity zirconium bonded to the inside surface of the alloy tube. The container encloses the core so as to leave a gap between the container and the core during use in a nuclear reactor. The metal barrier is of moderate purity zirconium with an impurity level on a weight basis of at least 1000ppm and less than 5000ppm. Impurity levels of specific elements are given. Variations of the invention are also specified. The composite cladding reduces chemical interaction, minimizes localized stress and strain corrosion and reduces the likelihood of a splitting failure in the zirconium alloy tube. Other benefits are claimed. (U.K.)

  17. Discontinuous Galerkin finite element method with anisotropic local grid refinement for inviscid compressible flows

    NARCIS (Netherlands)

    van der Vegt, Jacobus J.W.; van der Ven, H.

    1998-01-01

    A new discretization method for the three-dimensional Euler equations of gas dynamics is presented, which is based on the discontinuous Galerkin finite element method. Special attention is paid to an efficient implementation of the discontinuous Galerkin method that minimizes the number of flux

  18. Using the ion microprobe mass analyser for trace element analysis

    International Nuclear Information System (INIS)

    Schilling, J.H.

    1978-01-01

    Most techniques for the analysis of trace elements are capable of determining the concentrations in a bulk sample or solution, but without reflecting their distribution. In a bulk analysis therefore elements which occur in high concentration in a few precipitates would still be considered trace elements even though their local concentration greatly exceed the normally accepted trace elements concentration limit. Anomalous distribution is also shown by an oxide layer, a few hundred Angstrom thick, on an aluminium sample. A low oxide concentration would be reported if it were included in the bulk analysis, which contradicts the high surface concentration. The importance of a knowledge of the trace element distribution is therefore demonstrated. Distributional trace element analysis can be carried out using the ion microprobe mass analyser (IMMA). Since the analytical technique used in this instrument, namely secondary ion mass spectrometry (SIMS), is not universally appreciated, the instrument and its features will be described briefly followed by a discussion of quantitative analysis and the related subjects of detection limit and sample consumption. Finally, a few examples of the use of the instrument are given

  19. Design of horizontal-axis wind turbine using blade element momentum method

    Science.gov (United States)

    Bobonea, Andreea; Pricop, Mihai Victor

    2013-10-01

    The study of mathematical models applied to wind turbine design in recent years, principally in electrical energy generation, has become significant due to the increasing use of renewable energy sources with low environmental impact. Thus, this paper shows an alternative mathematical scheme for the wind turbine design, based on the Blade Element Momentum (BEM) Theory. The results from the BEM method are greatly dependent on the precision of the lift and drag coefficients. The basic of BEM method assumes the blade can be analyzed as a number of independent element in spanwise direction. The induced velocity at each element is determined by performing the momentum balance for a control volume containing the blade element. The aerodynamic forces on the element are calculated using the lift and drag coefficient from the empirical two-dimensional wind tunnel test data at the geometric angle of attack (AOA) of the blade element relative to the local flow velocity.

  20. Magnitude of pseudopotential localization errors in fixed node diffusion quantum Monte Carlo.

    Science.gov (United States)

    Krogel, Jaron T; Kent, P R C

    2017-06-28

    Growth in computational resources has lead to the application of real space diffusion quantum Monte Carlo to increasingly heavy elements. Although generally assumed to be small, we find that when using standard techniques, the pseudopotential localization error can be large, on the order of an electron volt for an isolated cerium atom. We formally show that the localization error can be reduced to zero with improvements to the Jastrow factor alone, and we define a metric of Jastrow sensitivity that may be useful in the design of pseudopotentials. We employ an extrapolation scheme to extract the bare fixed node energy and estimate the localization error in both the locality approximation and the T-moves schemes for the Ce atom in charge states 3+ and 4+. The locality approximation exhibits the lowest Jastrow sensitivity and generally smaller localization errors than T-moves although the locality approximation energy approaches the localization free limit from above/below for the 3+/4+ charge state. We find that energy minimized Jastrow factors including three-body electron-electron-ion terms are the most effective at reducing the localization error for both the locality approximation and T-moves for the case of the Ce atom. Less complex or variance minimized Jastrows are generally less effective. Our results suggest that further improvements to Jastrow factors and trial wavefunction forms may be needed to reduce localization errors to chemical accuracy when medium core pseudopotentials are applied to heavy elements such as Ce.

  1. Main-, minor- and trace elements distribution in human brain

    International Nuclear Information System (INIS)

    Zoeger, N.; Streli, C.; Wobrauschek, P.; Jokubonis, C.; Pepponi, G.; Roschger, P.; Bohic, S.; Osterode, W.

    2004-01-01

    Lead (Pb) is known to induce adverse health effects in humans. In fact, cognitive deficits are repeatedly described with Pb exposure, but little is known about the distribution of lead in brain. Measurements of the distribution of Pb in human brain and to study if Pb is associated with the distribution of other chemical elements such as zinc (Zn), iron (Fe) is of great interest and could reveal some hints about the metabolism of Pb in brain. To determine the local distribution of lead (Pb) and other trace elements x-ray fluorescence spectroscopy (XRF) measurements have been performed, using a microbeam setup and highest flux synchrotron radiation. Experiments have been carried out at ID-22, ESRF, Grenoble, France. The installed microprobe setup provides a monochromatic beam (17 keV) from an undulator station focused by Kirkpatrick-Baez x-ray optics to a spot size of 5 μm x 3μm. Brain slices (20 μm thickness, imbedded in paraffin and mounted on Kapton foils) from areas of the frontal cortex, thalamus and hippocampus have been investigated. Generally no significant increase in fluorescence intensities could be detected in one of the investigated brain compartments. However Pb and other (trace) elements (e.g. S, Ca, Fe, Cu, Zn, Br) could be detected in all samples and showed strong inhomogeneities across the analyzed areas. While S, Ca, Fe, Cu, Zn and Br could be clearly assigned to the investigated brain structures (vessels, etc.) Pb showed a very different behavior. In some cases (e.g. plexus choroidei) Pb was located at the walls of the vessel, whereas with other structures (e.g. blood vessel) this correlation was not found. Moreover, the detected Pb in different brain areas was individually correlated with various elements. The local distribution of the detected elements in various brain structures will be discussed in this work. (author)

  2. Chorus source region localization in the Earth's outer magnetosphere using THEMIS measurements

    Directory of Open Access Journals (Sweden)

    O. Agapitov

    2010-06-01

    Full Text Available Discrete ELF/VLF chorus emissions, the most intense electromagnetic plasma waves observed in the Earth's radiation belts and outer magnetosphere, are thought to propagate roughly along magnetic field lines from a localized source region near the magnetic equator towards the magnetic poles. THEMIS project Electric Field Instrument (EFI and Search Coil Magnetometer (SCM measurements were used to determine the spatial scale of the chorus source localization region on the day side of the Earth's outer magnetosphere. We present simultaneous observations of the same chorus elements registered onboard several THEMIS spacecraft in 2007 when all the spacecraft were in the same orbit. Discrete chorus elements were observed at 0.15–0.25 of the local electron gyrofrequency, which is typical for the outer magnetosphere. We evaluated the Poynting flux and wave vector distribution and obtained chorus wave packet quasi-parallel propagation to the local magnetic field. Amplitude and phase correlation data analysis allowed us to estimate the characteristic spatial correlation scale transverse to the local magnetic field to be in the 2800–3200 km range.

  3. Toxic Elements in Different Medicinal Plants and the Impact on Human Health.

    Science.gov (United States)

    Brima, Eid I

    2017-10-11

    Local medicinal plants from Madina, Saudi Arabia, are used to cure various diseases. However, some can cause adverse health effects. Five different medicinal plants were collected in the city of Madina: mahareeb ( Cymbopogon ), sheeh ( Artemisia ), harjal ( Cynanchum argel delile ), nabipoot ( Equisetum ), and kafmariam ( Vitex agnus-castus ). In total, four toxic elements including Al, Pb, As, and Cd were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The range of recoveries fell between 86.1 and 90.6% for all measured elements. Al levels were the highest of any of the studied elements in all plant samples, with Cymbopogon showing the highest levels. The range of concentrations of Al was 156-1609 mg/kg. Cd appeared at the lowest levels in all plants samples, with Vitex agnus-castus containing this element at the highest levels. Cd concentrations were in the range of 0.01-0.10 mg/kg. A washing process lowered the toxic elements in all plants; average % recoveries were Al (47.32%), As (59.1%), Cd (62.03%), and Pb (32.40%). The calculated human health risk assessment in one dose for toxic elements in all plants was as follows: Al (1.33 × 10 -3 -5.57 × 10 -2 mg/kg.bw), Pb (0-8.86 × 10 -5 mg/kg.bw), As (3.43 × 10 -7 -1.33 × 10 -5 mg/kg.bw), and Cd (0-3.14 × 10 -6 mg/kg.bw). Medicinal plants are a source of exposure to toxic elements. However, none of the plants in this study exceeded the daily guideline set by the WHO for any element based on conventional use by the local population. We may cautiously conclude that these medicinal plants pose no risk to users based on conventional use.

  4. Toxic Elements in Different Medicinal Plants and the Impact on Human Health

    Directory of Open Access Journals (Sweden)

    Eid I. Brima

    2017-10-01

    Full Text Available Local medicinal plants from Madina, Saudi Arabia, are used to cure various diseases. However, some can cause adverse health effects. Five different medicinal plants were collected in the city of Madina: mahareeb (Cymbopogon, sheeh (Artemisia, harjal (Cynanchum argel delile, nabipoot (Equisetum, and kafmariam (Vitex agnus-castus. In total, four toxic elements including Al, Pb, As, and Cd were analyzed using inductively coupled plasma mass spectrometry (ICP-MS. The range of recoveries fell between 86.1% and 90.6% for all measured elements. Al levels were the highest of any of the studied elements in all plant samples, with Cymbopogon showing the highest levels. The range of concentrations of Al was 156–1609 mg/kg. Cd appeared at the lowest levels in all plants samples, with Vitex agnus-castus containing this element at the highest levels. Cd concentrations were in the range of 0.01–0.10 mg/kg. A washing process lowered the toxic elements in all plants; average % recoveries were Al (47.32%, As (59.1%, Cd (62.03%, and Pb (32.40%. The calculated human health risk assessment in one dose for toxic elements in all plants was as follows: Al (1.33 × 10−3–5.57 × 10−2 mg/kg.bw, Pb (0–8.86 × 10−5 mg/kg.bw, As (3.43 × 10−7–1.33 × 10−5 mg/kg.bw, and Cd (0–3.14 × 10−6 mg/kg.bw. Medicinal plants are a source of exposure to toxic elements. However, none of the plants in this study exceeded the daily guideline set by the WHO for any element based on conventional use by the local population. We may cautiously conclude that these medicinal plants pose no risk to users based on conventional use.

  5. Toxic Elements in Different Medicinal Plants and the Impact on Human Health

    Science.gov (United States)

    Brima, Eid I.

    2017-01-01

    Local medicinal plants from Madina, Saudi Arabia, are used to cure various diseases. However, some can cause adverse health effects. Five different medicinal plants were collected in the city of Madina: mahareeb (Cymbopogon), sheeh (Artemisia), harjal (Cynanchum argel delile), nabipoot (Equisetum), and kafmariam (Vitex agnus-castus). In total, four toxic elements including Al, Pb, As, and Cd were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The range of recoveries fell between 86.1 and 90.6% for all measured elements. Al levels were the highest of any of the studied elements in all plant samples, with Cymbopogon showing the highest levels. The range of concentrations of Al was 156–1609 mg/kg. Cd appeared at the lowest levels in all plants samples, with Vitex agnus-castus containing this element at the highest levels. Cd concentrations were in the range of 0.01–0.10 mg/kg. A washing process lowered the toxic elements in all plants; average % recoveries were Al (47.32%), As (59.1%), Cd (62.03%), and Pb (32.40%). The calculated human health risk assessment in one dose for toxic elements in all plants was as follows: Al (1.33 × 10−3–5.57 × 10−2 mg/kg.bw), Pb (0–8.86 × 10−5 mg/kg.bw), As (3.43 × 10−7–1.33 × 10−5 mg/kg.bw), and Cd (0–3.14 × 10−6 mg/kg.bw). Medicinal plants are a source of exposure to toxic elements. However, none of the plants in this study exceeded the daily guideline set by the WHO for any element based on conventional use by the local population. We may cautiously conclude that these medicinal plants pose no risk to users based on conventional use. PMID:29019913

  6. Local rectification of heat flux

    Science.gov (United States)

    Pons, M.; Cui, Y. Y.; Ruschhaupt, A.; Simón, M. A.; Muga, J. G.

    2017-09-01

    We present a chain-of-atoms model where heat is rectified, with different fluxes from the hot to the cold baths located at the chain boundaries when the temperature bias is reversed. The chain is homogeneous except for boundary effects and a local modification of the interactions at one site, the “impurity”. The rectification mechanism is due here to the localized impurity, the only asymmetrical element of the structure, apart from the externally imposed temperature bias, and does not rely on putting in contact different materials or other known mechanisms such as grading or long-range interactions. The effect survives if all interaction forces are linear except the ones for the impurity.

  7. Trace elements in digestive cancer tissue by PIXE

    International Nuclear Information System (INIS)

    Ciortea, C.; Constantinescu, O.; Cata, I.; Dumitriu, D. E.; Enulescu, A.; Fluerasu, D.; Pantelica, A.; Penescu, L. C.; Piticu, I.; Radu, A. T.; Vargolici, M.; Ciortea, M.; Staniceanu, F.; Popescu, E.; Donciu, D.; Moldovan, A.; Popescu, L.; Burghelea, B.

    2004-01-01

    Elemental composition study of digestive cancer tissue with different localizations (esophagus, stomach, colon) by using PIXE analysis is presented. A number of 20 tumor and normal (control) tissue samples were analyzed. Thin targets were prepared by mineralization of the lyophilized tissue with nitric acid and dropping on 2 μm Mylar foil. The measurements were carried out in vacuum using 3 MeV protons delivered by the tandem accelerator in Bucharest, Romania. The following elements were identified: S, Cl, K, Ca, Cr, Mn, Fe, Cu and Zn. Although the results show relatively large variations from a sample to another there were obtained mean ratios of tumor/normal concentrations which are significantly greater than one, in the limit of the standard deviation for the following elements: K (1.45±0.28), Ca (1.30±0.21), Cr (2.33±0.56), and Zn (1.18±0.15). For the other determined elements, no significant difference between the tumor and normal tissues, in the limit of the present standard deviation, was found. (authors)

  8. Trace elements in digestive cancer tissue by PIXE

    International Nuclear Information System (INIS)

    Ciortea, Constantin; Constantinescu, Olimpiu; Filimon, Andrei

    2005-01-01

    Elemental composition study of digestive cancer tissue with different localizations (esophagus, stomach, colon), by using PIXE analysis, is presented. A number of 20 tumors and normal (control) tissue samples was analyzed. Thin targets were prepared by mineralization with nitric acid of the lyophilized tissue and dropping on 2 μm Mylar foil. The measurements were carried out in vacuum using 3 MeV protons delivered by the Tandem Accelerator in Bucharest, Romania. The following elements were determined: S, Cl, K, Ca, Cr, Mn, Fe, Cu and Zn. Although the results show relatively large variations from a sample to another, there were obtained mean ratios of tumor/normal concentrations which are significantly greater than one, in the limit of the standard deviation, for the following elements: K(1.45 ± 0.28), Ca(1.30 ± 0.21), Cr(2.33 ± 0.56), and Zn(1.18 ± 0.15). For other elements determined, no significant difference between the tumor and normal tissues , in the limit of the present standard deviation, was found. (authors)

  9. Lower bound element and submodel for modelling of joints between precast concrete panels

    DEFF Research Database (Denmark)

    Herfelt, Morten Andersen; Poulsen, Peter Noe; Hoang, Linh Cao

    2015-01-01

    In practice, precast concrete structures are designed using either analytical methods or linear finite element tools, and the in-situ cast joints between the precast panels are assessed using conservative empirical design formulas. This often leads to a suboptimal design, and local mechanisms ins....... The computational time and problem size of the joint element and detailed model will be discussed....

  10. Local polarization phenomena in In-doped CdTe x-ray detector arrays

    International Nuclear Information System (INIS)

    Sato, Toshiyuki; Sato, Kenji; Ishida, Shinichiro; Kiri, Motosada; Hirooka, Megumi; Yamada, Masayoshi; Kanamori, Hitoshi

    1995-01-01

    Local polarization phenomena have been studied in detector arrays with the detector element size of 500 microm x 500 microm, which are fabricated from high-resistivity In-doped CdTe crystals grown by the vertical Bridgman technique. It has been found for the first time that a polarization effect, which is characterized by a progressive decrease of the pulse counting rate with increasing photon fluence, strongly depends on the detector elements, that is, the portion of crystals used. The influence of several parameters, such as the applied electric field strength, time, and temperature, on this local polarization effect is also investigated. From the photoluminescence measurements of the inhomogeneity of In dopant, it is concluded that the local polarization effect observed here originates from a deep level associated with In dopant in CdTe crystals

  11. Numerical modeling of the dynamic behavior of structures under impact with a discrete elements / finite elements coupling

    International Nuclear Information System (INIS)

    Rousseau, J.

    2009-07-01

    That study focuses on concrete structures submitted to impact loading and is aimed at predicting local damage in the vicinity of an impact zone as well as the global response of the structure. The Discrete Element Method (DEM) seems particularly well suited in this context for modeling fractures. An identification process of DEM material parameters from macroscopic data (Young's modulus, compressive and tensile strength, fracture energy, etc.) will first be presented for the purpose of enhancing reproducibility and reliability of the simulation results with DE samples of various sizes. Then, a particular interaction, between concrete and steel elements, was developed for the simulation of reinforced concrete. The discrete elements method was validated on quasi-static and dynamic tests carried out on small samples of concrete and reinforced concrete. Finally, discrete elements were used to simulate impacts on reinforced concrete slabs in order to confront the results with experimental tests. The modeling of a large structure by means of DEM may lead to prohibitive computation times. A refined discretization becomes required in the vicinity of the impact, while the structure may be modeled using a coarse FE mesh further from the impact area, where the material behaves elastically. A coupled discrete-finite element approach is thus proposed: the impact zone is modeled by means of DE and elastic FE are used on the rest of the structure. An existing method for 3D finite elements was extended to shells. This new method was then validated on many quasi-static and dynamic tests. The proposed approach is then applied to an impact on a concrete structure in order to validate the coupled method and compare computation times. (author)

  12. Towards optimal design of locally resonant acoustic metamaterials

    NARCIS (Netherlands)

    Krushynska, A.O.; Kouznetsova, V.; Geers, M.G.D.

    2014-01-01

    The paper presents an in-depth analysis of solid locally resonant acoustic metamaterials (LRAMs) consisting of rubber-coated inclusions. Dispersion properties of two-dimensional LRAMs are studied by means of finite-element modal analysis. For an incompressible rubber, only one practically important

  13. Application of global elements to a reinforced concrete structure

    International Nuclear Information System (INIS)

    Morand, O.

    1994-01-01

    The dimensioning of nuclear facilities requires to take into account the possible risk of earthquakes. However such installations are generally complex structures with reinforced concrete poles, walls, beams and porches. In this study, a seismic analysis of such a structure is proposed. The use of the Castem 2000 global element code was attempted to dynamically simulate the behaviour of the reinforced concrete elements. However, no suitable modeling has been found for the storeys, the functioning of which being dominated by carrying walls. Concerning the porch-type storeys, monotonous static loads were simulated and provided information on the local and global behaviour of these structures. Thus, representative global elements could be realized for these structures. Results obtained are satisfactory for these storeys which essentially undergo a bending deformation. (J.S.)

  14. Simulation of air-heated evaporators using a method of local analysis

    International Nuclear Information System (INIS)

    Parise, J.A.R.; Cartwright, W.G.

    1983-01-01

    The development and application of an analytical method for the performance prediction of air-heated evaporators are presented. A local analysis is employed in which the evaporator is considered as a three dimensional matrix of elementary heat transfer modules. For each element, local film coefficients for both air and the evaporating fluid are determined appropriate to the local conditions, including the two-phase flow regime. An application of the method is considered. (Author) [pt

  15. Determination of essential and toxic elements in commercially available fruit juices

    International Nuclear Information System (INIS)

    Yawar, W.; Rahman, S.

    1997-01-01

    A study has been carried out for the determination of Cr, Pb, Fe in different varieties of commercially available packed fruit juices like apple, mango orange and mixed flavour by using flame and electrothermal atomic absorption spectrophotometric technique. These juices are available at a reasonable price and are commonly used by public. Like many other articles the baseline levels of essential and toxic elements in Pakistani fruit juices are generally not available. It was, therefore, considered to monitor the levels of essential as well toxic elements in the juices. Hence a variety of juices was collected from local market and measurements of the above mentioned elements were made. (author)

  16. Instrument for track linear element recognition

    International Nuclear Information System (INIS)

    Krupnov, V.E.; Fedotov, O.P.

    1977-01-01

    Described is the construction of instrument for recognizing linear elements of tracks. For designing this instrument use has been made of the algorithm for conversion of the point data into a set of linear elements. The flowsheet of the instrument shows its major units such as data converter, data representation register unit, local computers, interface with the central computer. The data representation register unit comprises sixteen registers and is capable of presenting data from sixteen lines when raster scanning of a picture taken from a track chamber. The maximum capacity of the code of the coordinate of a point recorded on a picture is up to 16 digits. The time of the inner operating cycle of the instrument is 1.3 μs. The average time required for processing data containing sixteen scanning lines is 250 μs

  17. The fabrication of nuclear fuel elements in Mexico

    International Nuclear Information System (INIS)

    Guerrero Morillo, H.L.

    1977-01-01

    The situation of nuclear electricity generation in Mexico in 1976 is described: two nuclear reactors were under construction but no definite programme on the type and start-up dates for the next power plants existed. However, the existence of a general plan on nuclear power plants is mentioned, which, according to the latest estimates, will provide 10,000MW installed by 1990. The national intention, as laid down in an appropriate Law, is to supply domestic nuclear fuel to the power reactors operating in the country, starting with the first reloading of the two BWRs at the first national station in Laguna Verde, required at the end of 1981 and 1982, respectively. Before this can be achieved and to provide the relatively small amounts of fuel elements for the two reactors, Mexico must adopt a strategy of fuel elements fabrication. The two main options are analysed: (1) to delay local fabrication until a national nuclear programme has been defined, meanwhile purchasing abroad the necessary initial cores and refuelling; (2) to start local fabrication of fuel elements as soon as possible in order to provide the first refuelling of the first unit of Laguna Verde, confronting the economic risks of such a decision with the advantages of immediate action. Both options are analysed in detail, comparing them especially from the economic point of view. Current information from potential licensors for design and manufacture are used in the analysis. (author)

  18. Local variances in biomonitoring

    International Nuclear Information System (INIS)

    Wolterbeek, H.T.

    1999-01-01

    The present study deals with the (larger-scaled) biomonitoring survey and specifically focuses on the sampling site. In most surveys, the sampling site is simply selected or defined as a spot of (geographical) dimensions which is small relative to the dimensions of the total survey area. Implicitly it is assumed that the sampling site is essentially homogeneous with respect to the investigated variation in survey parameters. As such, the sampling site is mostly regarded as 'the basic unit' of the survey. As a logical consequence, the local (sampling site) variance should also be seen as a basic and important characteristic of the survey. During the study, work is carried out to gain more knowledge of the local variance. Multiple sampling is carried out at a specific site (tree bark, mosses, soils), multi-elemental analyses are carried out by NAA, and local variances are investigated by conventional statistics, factor analytical techniques, and bootstrapping. Consequences of the outcomes are discussed in the context of sampling, sample handling and survey quality. (author)

  19. Determination of the elemental content in cigarettes by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Metwally, E.

    2001-01-01

    Cigarette smoking, a worldwide habit, has a very bad and hazardous effect on the human body. Neutron activation analysis technique is used in the present study. Different kinds of cigarette brands have been collected from local and foreign markets representing ten countries all over the world. All the selected samples are irradiated in first Ins has reactor, ER-1 in Egypt. A comprehensive study of the elemental content in cigarette samples under investigation has been carried out. Concentrations of the polluting elements, tracers' content and more than twenty elements have been determined. The obtained data resulting from the present work are discussed

  20. You look familiar, but I don’t care: Lure rejection in hybrid visual and memory search is not based on familiarity

    Science.gov (United States)

    Wolfe, Jeremy M.; Boettcher, Sage E. P.; Josephs, Emilie L.; Cunningham, Corbin A.; Drew, Trafton

    2015-01-01

    In “hybrid” search tasks, observers hold multiple possible targets in memory while searching for those targets amongst distractor items in visual displays. Wolfe (2012) found that, if the target set is held constant over a block of trials, RTs in such tasks were a linear function of the number of items in the visual display and a linear function of the log of the number of items held in memory. However, in such tasks, the targets can become far more familiar than the distractors. Does this “familiarity” – operationalized here as the frequency and recency with which an item has appeared – influence performance in hybrid tasks In Experiment 1, we compared searches where distractors appeared with the same frequency as the targets to searches where all distractors were novel. Distractor familiarity did not have any reliable effect on search. In Experiment 2, most distractors were novel but some critical distractors were as common as the targets while others were 4× more common. Familiar distractors did not produce false alarm errors, though they did slightly increase response times (RTs). In Experiment 3, observers successfully searched for the new, unfamiliar item among distractors that, in many cases, had been seen only once before. We conclude that when the memory set is held constant for many trials, item familiarity alone does not cause observers to mistakenly confuse target with distractors. PMID:26191615

  1. Multivariate localization methods for ensemble Kalman filtering

    KAUST Repository

    Roh, S.

    2015-12-03

    In ensemble Kalman filtering (EnKF), the small number of ensemble members that is feasible to use in a practical data assimilation application leads to sampling variability of the estimates of the background error covariances. The standard approach to reducing the effects of this sampling variability, which has also been found to be highly efficient in improving the performance of EnKF, is the localization of the estimates of the covariances. One family of localization techniques is based on taking the Schur (element-wise) product of the ensemble-based sample covariance matrix and a correlation matrix whose entries are obtained by the discretization of a distance-dependent correlation function. While the proper definition of the localization function for a single state variable has been extensively investigated, a rigorous definition of the localization function for multiple state variables that exist at the same locations has been seldom considered. This paper introduces two strategies for the construction of localization functions for multiple state variables. The proposed localization functions are tested by assimilating simulated observations experiments into the bivariate Lorenz 95 model with their help.

  2. Multivariate localization methods for ensemble Kalman filtering

    Science.gov (United States)

    Roh, S.; Jun, M.; Szunyogh, I.; Genton, M. G.

    2015-12-01

    In ensemble Kalman filtering (EnKF), the small number of ensemble members that is feasible to use in a practical data assimilation application leads to sampling variability of the estimates of the background error covariances. The standard approach to reducing the effects of this sampling variability, which has also been found to be highly efficient in improving the performance of EnKF, is the localization of the estimates of the covariances. One family of localization techniques is based on taking the Schur (element-wise) product of the ensemble-based sample covariance matrix and a correlation matrix whose entries are obtained by the discretization of a distance-dependent correlation function. While the proper definition of the localization function for a single state variable has been extensively investigated, a rigorous definition of the localization function for multiple state variables that exist at the same locations has been seldom considered. This paper introduces two strategies for the construction of localization functions for multiple state variables. The proposed localization functions are tested by assimilating simulated observations experiments into the bivariate Lorenz 95 model with their help.

  3. Levels of essential and non-essential elements in commercially ...

    African Journals Online (AJOL)

    The focus of this study was to assess the quality of commercially packaged moringa tea brands available in the retail markets in Nigerian cities on the basis of the essential and nonessential elemental content in their tissues. Four different brands of moringa tea comprising two locally processed teas and two imported teas ...

  4. Identifying Bottom-Up and Top-Down Components of Attentional Weight by Experimental Analysis and Computational Modeling

    DEFF Research Database (Denmark)

    Nordfang, Maria; Dyrholm, Mads; Bundesen, Claus

    2013-01-01

    effects of feature contrast (color singleton vs. nonsingleton) and relevance (target vs. distractor). A singleton target had a higher probability of being reported than did a nonsingleton target, and a singleton distractor interfered more strongly with report of targets than did a nonsingleton distractor...... stimuli but unspeeded responses. The task was to report the letters from a mixture of letters (targets) and digits (distractors). Color was irrelevant to the task, but many stimulus displays contained an item (target or distractor) in a deviant color (a color singleton). The results showed concurrent...

  5. Effective beam method for element concentrations

    International Nuclear Information System (INIS)

    Tolhurst, Thomas; Barbi, Mauricio; Tokaryk, Tim

    2015-01-01

    A method to evaluate chemical element concentrations in samples by generating an effective polychromatic beam using as initial input real monochromatic beam data is presented. There is a great diversity of research being conducted at synchrotron facilities around the world and a diverse set of beamlines to accommodate this research. Time is a precious commodity at synchrotron facilities; therefore, methods that can maximize the time spent collecting data are of value. At the same time the incident radiation spectrum, necessary for some research, may not be known on a given beamline. A preliminary presentation of a method applicable to X-ray fluorescence spectrocopic analyses that overcomes the lack of information about the incident beam spectrum that addresses both of these concerns is given here. The method is equally applicable for other X-ray sources so long as local conditions are considered. It relies on replacing the polychromatic spectrum in a standard fundamental parameters analysis with a set of effective monochromatic photon beams. A beam is associated with each element and can be described by an analytical function allowing extension to elements not included in the necessary calibration measurement(s)

  6. Airborne chemical elements in Spanish moss

    Energy Technology Data Exchange (ETDEWEB)

    Shacklette, H.T.; Connor, J.J.

    1973-01-01

    Spanish moss (Tillandsia usneoides L.), collected from its geographic range in Southern United States, was analyzed for 38 chemical elements in 123 samples. Analyses of Spanish moss samples collected at rural, residential, highway, and industrial locations reflected significant differences in concentrations of metals. Samples from industrial and highway locations are characterized as containing greater-than-average amounts of arsenic, cadmium, chromium, cobalt, copper, lead, nickel, and vanadium. The high levels of lead found in some samples from highway locations are especially noteworthy. Many samples from sites near the seashore contained greater-than-average amounts of sodium that is thought to have been derived from ocean spray. Samples from rural locations commonly contain low concentrations of the metal usually associated with industrial or urban activity but may contain large amounts of the elements that are ordinary constituents of soil dust. Four of six samples containing detectable amounts of tin were collected within 50 miles of the only tin smelter in the United States; this result suggests that elemental analyses of Spanish moss samples can provide an economical and rapid method of estimating the kind and relative degree of local atmospheric metal pollution.

  7. A collapse mode of failure in powder-filled fuel elements

    International Nuclear Information System (INIS)

    Feraday, M.A.; Chalder, G.H.

    1964-01-01

    Two swaged fuel elements containing crushed, fused UO 2 powder were irradiated in a pressurized water loop at high heat ratings (∫Kdθ = 48 w/cm). The fuel elements were 2.0 cm in diameter and were sheathed in nickel-free Zircaloy--2 of 0.038 cm thickness. One element failed when the sheath ruptured at the top of a longitudinal ridge in the sheath after a burn-up of approximately 2550 MWd/TeU. No evidence was found that outgassing of the UO 2 contributed to the failure. Dimensional and structural changes observed in the fuel elements led to the conclusion that ridging of the sheath resulted from the action of coolant pressure on the diametral clearance formed by sintering and shrinkage of the UO 2 . Failure resulted due to severe local deformation accompanying one or more power cycles following ridge formation. (author)

  8. Environmental mineralogy - Understanding element behavior in ecosystems; Mineralogie environnementale: comprendre le comportement des elements dans les ecosystemes

    Energy Technology Data Exchange (ETDEWEB)

    Brown Jr, G.E. [Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305-2115 (United States); Department of Photon Science and Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Calas, G. [Institut de mineralogie et de physique des milieux condenses (IMPMC), universite Paris-6 - universite Paris-7, IPGP, CNRS, case 115, 75252 Paris (France)

    2011-02-15

    Environmental Mineralogy has developed over the past decade in response to the recognition that minerals are linked in many important ways with the global ecosystem. Minerals are the main repositories of the chemical elements in Earth's crust and thus are the main sources of elements needed for the development of civilization, contaminant and pollutant elements that impact global and local ecosystems, and elements that are essential plant nutrients. These elements are released from minerals through natural processes, such as chemical weathering, and anthropogenic activities, such as mining and energy production, agriculture and industrial activities, and careless waste disposal. Minerals also play key roles in the biogeochemical cycling of the elements, sequestering elements and releasing them as the primary minerals in crustal rocks undergo various structural and compositional transformations in response to physical, chemical, and biological processes that produce secondary minerals and soils. These processes have resulted in the release of toxic elements such as arsenic in groundwater aquifers, which is having a major impact on the health of millions of people in South and Southeast Asia. The interfaces between mineral surfaces and aqueous solutions are the locations of most chemical reactions that control the composition of the natural environment, including the composition of natural waters. The nuclear fuel cycle, from uranium mining to the disposition of high-level nuclear waste, is also intimately related to minerals. A fundamental understanding of these processes requires molecular-scale information about minerals, their bulk structures and properties such as solubility, their surfaces, and their interactions with aqueous solutions, atmospheric and soil gases, natural organic matter, and biological organisms. Gaining this understanding is further complicated by the presence of natural, incidental, and manufactured nano-particles in the environment

  9. Training elements at different levels in the strategies for control of schistosomiasis

    DEFF Research Database (Denmark)

    Ørnbjerg, Niels; Simonsen, P. E.; Furu, Peter

    1989-01-01

    Recently acquired comprehensive knowledge concerning the epidemiology of schistosomiasis has provided the background for the establishment of schistosomiasis control strategies. However, the planning, implementation, and maintenance of such control programmes requires sufficient numbers of well t...... trained personnel at the local, district and central levels. Training of health personnel as well as motivation of the community are fundamental and essential elements in any schistosomiasis control programme. The training elements and approaches are discussed....

  10. Groundwater flow analysis using mixed hybrid finite element method for radioactive waste disposal facilities

    International Nuclear Information System (INIS)

    Aoki, Hiroomi; Shimomura, Masanori; Kawakami, Hiroto; Suzuki, Shunichi

    2011-01-01

    In safety assessments of radioactive waste disposal facilities, ground water flow analysis are used for calculating the radionuclide transport pathway and the infiltration flow rate of groundwater into the disposal facilities. For this type of calculations, the mixed hybrid finite element method has been used and discussed about the accuracy of ones in Europe. This paper puts great emphasis on the infiltration flow rate of groundwater into the disposal facilities, and describes the accuracy of results obtained from mixed hybrid finite element method by comparing of local water mass conservation and the reliability of the element breakdown numbers among the mixed hybrid finite element method, finite volume method and nondegenerated finite element method. (author)

  11. Generalized multiscale finite element methods: Oversampling strategies

    KAUST Repository

    Efendiev, Yalchin R.; Galvis, Juan; Li, Guanglian; Presho, Michael

    2014-01-01

    In this paper, we propose oversampling strategies in the generalized multiscale finite element method (GMsFEM) framework. The GMsFEM, which has been recently introduced in Efendiev et al. (2013b) [Generalized Multiscale Finite Element Methods, J. Comput. Phys., vol. 251, pp. 116-135, 2013], allows solving multiscale parameter-dependent problems at a reduced computational cost by constructing a reduced-order representation of the solution on a coarse grid. The main idea of the method consists of (1) the construction of snapshot space, (2) the construction of the offline space, and (3) construction of the online space (the latter for parameter-dependent problems). In Efendiev et al. (2013b) [Generalized Multiscale Finite Element Methods, J. Comput. Phys., vol. 251, pp. 116-135, 2013], it was shown that the GMsFEM provides a flexible tool to solve multiscale problems with a complex input space by generating appropriate snapshot, offline, and online spaces. In this paper, we develop oversampling techniques to be used in this context (see Hou and Wu (1997) where oversampling is introduced for multiscale finite element methods). It is known (see Hou and Wu (1997)) that the oversampling can improve the accuracy of multiscale methods. In particular, the oversampling technique uses larger regions (larger than the target coarse block) in constructing local basis functions. Our motivation stems from the analysis presented in this paper, which shows that when using oversampling techniques in the construction of the snapshot space and offline space, GMsFEM will converge independent of small scales and high contrast under certain assumptions. We consider the use of a multiple eigenvalue problems to improve the convergence and discuss their relation to single spectral problems that use oversampled regions. The oversampling procedures proposed in this paper differ from those in Hou and Wu (1997). In particular, the oversampling domains are partially used in constructing local

  12. Magnetic microscopy for characterization of local critical current in iron-sheathed MgB2 wires

    International Nuclear Information System (INIS)

    Higashikawa, K.; Yamamoto, A.; Kiss, T.; Ye, S.; Matsumoto, A.; Kumakura, H.

    2014-01-01

    Highlights: • We developed a characterization method of local critical current in MgB 2 wires. • Local homogeneity was visualized by the scanning Hall-probe microscopy (SHPM). • Local critical current value was quantified with the aid of the finite element method (FEM). • MgB 2 wire still has inhomogeneous distribution in local critical current. • Higher potential than that estimated by the four-probe transport method was suggested. - Abstract: We have developed a characterization method of local critical current in iron-sheathed MgB 2 wires. Local homogeneity was visualized by the scanning Hall-probe microscopy (SHPM). The value of local critical current was quantified with the aid of the finite element method (FEM) considering the ferromagnetic properties of the iron sheath. The results suggested that MgB 2 wires fabricated by internal Mg diffusion processes still have large longitudinal inhomogeneity and much higher potential than that estimated by the four-probe transport method. This will be very important information for making a correct strategy for further development of MgB 2 wires

  13. Local moments and electronic correlations in Fe-based Heusler alloys: Kα x-ray emission spectra measurements

    International Nuclear Information System (INIS)

    Svyazhin, Artem; Kurmaev, Ernst; Shreder, Elena; Shamin, Sergey; Sahle, Christoph J.

    2016-01-01

    Heusler alloys are a property-rich class of materials, intensively investigated today from both theoretical and real-world application points of view. In this paper, we attempt to shed light on the role of electronic correlations in the Fe_2MeAl group (where Me represents all 3d elements from Ti to Ni) of Heusler alloys. For this purpose, we have investigated the local moments of iron by means of the x-ray emission spectroscopy technique. To obtain numerical values of local moments, the Kα-FWHM method has been employed for the first time. In every compound of the group, the presence of a local moment on the Fe atom was detected. As has been revealed, the values of these moments are temperature-independent, pointing to an insufficiency of a pure itinerant approach to magnetism in these alloys. We also comprehensively compare the usage of Kβ main lines and Kα spectra as tools for the probing of local moments and point out the significant advantages of the latter. - Highlights: • Local spin moments of iron in Fe_2MeAl (Me = Ti … Ni) Heusler alloys were investigated by means of x-ray emission spectroscopy. • Independence of the local moments from temperature confirms their localized nature. • A local moment value of iron in Fe_2MeAl raises with the atomic number of element Me. • The applicability of the Kα x-ray emission line for extracting local moment values of 3d elements was established.

  14. Influence of Global and Local Membrane Curvature on Mechanosensitive Ion Channels: A Finite Element Approach

    Directory of Open Access Journals (Sweden)

    Omid Bavi

    2016-02-01

    Full Text Available Mechanosensitive (MS channels are ubiquitous molecular force sensors that respond to a number of different mechanical stimuli including tensile, compressive and shear stress. MS channels are also proposed to be molecular curvature sensors gating in response to bending in their local environment. One of the main mechanisms to functionally study these channels is the patch clamp technique. However, the patch of membrane surveyed using this methodology is far from physiological. Here we use continuum mechanics to probe the question of how curvature, in a standard patch clamp experiment, at different length scales (global and local affects a model MS channel. Firstly, to increase the accuracy of the Laplace’s equation in tension estimation in a patch membrane and to be able to more precisely describe the transient phenomena happening during patch clamping, we propose a modified Laplace’s equation. Most importantly, we unambiguously show that the global curvature of a patch, which is visible under the microscope during patch clamp experiments, is of negligible energetic consequence for activation of an MS channel in a model membrane. However, the local curvature (RL < 50 and the direction of bending are able to cause considerable changes in the stress distribution through the thickness of the membrane. Not only does local bending, in the order of physiologically relevant curvatures, cause a substantial change in the pressure profile but it also significantly modifies the stress distribution in response to force application. Understanding these stress variations in regions of high local bending is essential for a complete understanding of the effects of curvature on MS channels.

  15. Macrodystrophia Lipomatosa: An Unusual Cause of Localized Gigantism.

    Science.gov (United States)

    Maheswari, S Uma; Sampath, V; Ramesh, A; Manoharan, K

    2016-01-01

    Macrodystrophia lipomatosa (MDL) is a rare congenital form of localized gigantism characterized by progressive overgrowth of all mesenchymal elements with a disproportionate increase in fibro adipose tissue. Here we report a case of 20 years old male who presented with history of painless gradual enlargement of entire left upper limb since childhood. Magnetic resonance imaging and histopathology confirmed the diagnosis of macrodystrophia lipomatosa. This condition has to be differentiated from other causes of localized gigantism, since these conditions differ in their course, prognosis, complications and treatment.

  16. Magnitude of localized magnetic moments in metals

    International Nuclear Information System (INIS)

    Kiwi, M.; Pestana, E.; Ramirez, R.

    1979-01-01

    The magnitude of the localized magnetic moment of a transition or rare earth element impurity in a metal is evaluated within the framework of the Anderson model. Rotational invariance is preserved throughout. Graphs of the magnitude of the magnetization as a function of the relevant parameters of the model are provided and discussed. (author)

  17. Three dimensional finite element linear analysis of reinforced concrete structures

    International Nuclear Information System (INIS)

    Inbasakaran, M.; Pandarinathan, V.G.; Krishnamoorthy, C.S.

    1979-01-01

    A twenty noded isoparametric reinforced concrete solid element for the three dimensional linear elastic stress analysis of reinforced concrete structures is presented. The reinforcement is directly included as an integral part of the element thus facilitating discretization of the structure independent of the orientation of reinforcement. Concrete stiffness is evaluated by taking 3 x 3 x 3 Gauss integration rule and steel stiffness is evaluated numerically by considering three Gaussian points along the length of reinforcement. The numerical integration for steel stiffness necessiates the conversion of global coordiantes of the Gaussian points to nondimensional local coordinates and this is done by Newton Raphson iterative method. Subroutines for the above formulation have been developed and added to SAP and STAP routines for solving the examples. The validity of the reinforced concrete element is verified by comparison of results from finite element analysis and analytical results. It is concluded that this finite element model provides a valuable analytical tool for the three dimensional elastic stress analysis of concrete structures like beams curved in plan and nuclear containment vessels. (orig.)

  18. Shape representation modulating the effect of motion on visual search performance.

    Science.gov (United States)

    Yang, Lindong; Yu, Ruifeng; Lin, Xuelian; Liu, Na

    2017-11-02

    The effect of motion on visual search has been extensively investigated, but that of uniform linear motion of display on search performance for tasks with different target-distractor shape representations has been rarely explored. The present study conducted three visual search experiments. In Experiments 1 and 2, participants finished two search tasks that differed in target-distractor shape representations under static and dynamic conditions. Two tasks with clear and blurred stimuli were performed in Experiment 3. The experiments revealed that target-distractor shape representation modulated the effect of motion on visual search performance. For tasks with low target-distractor shape similarity, motion negatively affected search performance, which was consistent with previous studies. However, for tasks with high target-distractor shape similarity, if the target differed from distractors in that a gap with a linear contour was added to the target, and the corresponding part of distractors had a curved contour, motion positively influenced search performance. Motion blur contributed to the performance enhancement under dynamic conditions. The findings are useful for understanding the influence of target-distractor shape representation on dynamic visual search performance when display had uniform linear motion.

  19. Local-field refinement of neutron scattering lengths

    International Nuclear Information System (INIS)

    Sears, V.F.

    1985-01-01

    We examine the way in which local field effects in the neutron refractive index affect the values of coherent scattering lengths determined by various kinds of neutron optical measurements. We find that under typical experimental conditions these effects are negligible for interferometry measurements but that they are significant for gravity refractometry measurements, producing changes in the effective scattering length of as much as two or three standard deviations in some cases. Refined values of the scattering length are obtained for the thirteen elements for which data are presently available. The special role of local field effects in neutron transmission is also discussed. (orig.)

  20. Local-field refinement of neutron scattering lengths

    Energy Technology Data Exchange (ETDEWEB)

    Sears, V F

    1985-06-01

    We examine the way in which local field effects in the neutron refractive index affect the values of coherent scattering lengths determined by various kinds of neutron optical measurements. We find that under typical experimental conditions these effects are negligible for interferometry measurements but that they are significant for gravity refractometry measurements, producing changes in the effective scattering length of as much as two or three standard deviations in some cases. Refined values of the scattering length are obtained for the thirteen elements for which data are presently available. The special role of local field effects in neutron transmission is also discussed.

  1. Focusing light through random photonic layers by four-element division algorithm

    Science.gov (United States)

    Fang, Longjie; Zhang, Xicheng; Zuo, Haoyi; Pang, Lin

    2018-02-01

    The propagation of waves in turbid media is a fundamental problem of optics with vast applications. Optical phase optimization approaches for focusing light through turbid media using phase control algorithm have been widely studied in recent years due to the rapid development of spatial light modulator. The existing approaches include element-based algorithms - stepwise sequential algorithm, continuous sequential algorithm and whole element optimization approaches - partitioning algorithm, transmission matrix approach and genetic algorithm. The advantage of element-based approaches is that the phase contribution of each element is very clear; however, because the intensity contribution of each element to the focal point is small especially for the case of large number of elements, the determination of the optimal phase for a single element would be difficult. In other words, the signal to noise ratio of the measurement is weak, leading to possibly local maximal during the optimization. As for whole element optimization approaches, all elements are employed for the optimization. Of course, signal to noise ratio during the optimization is improved. However, because more random processings are introduced into the processing, optimizations take more time to converge than the single element based approaches. Based on the advantages of both single element based approaches and whole element optimization approaches, we propose FEDA approach. Comparisons with the existing approaches show that FEDA only takes one third of measurement time to reach the optimization, which means that FEDA is promising in practical application such as for deep tissue imaging.

  2. On the nature of phase attraction in sensorimotor synchronization with interleaved auditory sequences.

    Science.gov (United States)

    Repp, Bruno H

    2004-10-01

    In a task that requires in-phase synchronization of finger taps with an isochronous sequence of target tones that is interleaved with a sequence of distractor tones at various fixed phase relationships, the taps tend to be attracted to the distractor tones, especially when the distractor tones closely precede the target tones [Repp, B. H. (2003a). Phase attraction in sensorimotor synchronization with auditory sequences: Effects of single and periodic distractors on synchronization accuracy. Journal of Experimental Psychology: Human Perception and Performance, 29, 290-309]. The present research addressed two related questions about this distractor effect: (1) Is it a function of the absolute temporal separation or of the relative phase of the two stimulus sequences? (2) Is it the result of perceptual grouping (integration) of target and distractor tones or of simultaneous attraction to two independent sequences? In three experiments, distractor effects were compared across two different sequence rates. The results suggest that absolute temporal separation, not relative phase, is the critical variable. Experiment 3 also included an anti-phase tapping task that addressed the second question directly. The results suggest that the attraction of taps to distractor tones is caused mainly by temporal integration of target and distractor tones within a fixed window of 100-150 ms duration, with the earlier-occurring tone being weighted more strongly than the later-occurring one.

  3. Conformational determinants of the intracellular localization of midkine

    International Nuclear Information System (INIS)

    Dai Lichen; Xu, Diyong; Yao Xing; Lu Yongliang; Xu Zhengping

    2005-01-01

    Midkine (MK) is a multifunctional growth factor and has been discovered to play important roles in carcinogenesis. MK has been reported to localize to the nucleus and nucleolus, however, the data are not consistent and the signals responsible for the localization are unknown. Here we reported that human MK exclusively localized to the nucleus and nucleolus in HepG2 cells by using GFP as a tracking molecule. In order to identify the motifs required for the nuclear localization and nucleolar accumulation, point- and deletion-mutations were introduced and the corresponding subcellular localizations were analyzed. Data revealed that (i) K79R81, K86K87, and the C-terminal tail of MK constitute the nuclear localization determinant of MK, and (ii) the C-terminal tail is the key element controlling MK nucleolar accumulation though the N-terminal tail, K79R81, and K86K87 also contribute to this process. Taken together, our results provide the first documentation about the determinants required for MK nuclear and nucleolar localization

  4. Experimental validation of finite element analysis of human vertebral collapse under large compressive strains.

    Science.gov (United States)

    Hosseini, Hadi S; Clouthier, Allison L; Zysset, Philippe K

    2014-04-01

    Osteoporosis-related vertebral fractures represent a major health problem in elderly populations. Such fractures can often only be diagnosed after a substantial deformation history of the vertebral body. Therefore, it remains a challenge for clinicians to distinguish between stable and progressive potentially harmful fractures. Accordingly, novel criteria for selection of the appropriate conservative or surgical treatment are urgently needed. Computer tomography-based finite element analysis is an increasingly accepted method to predict the quasi-static vertebral strength and to follow up this small strain property longitudinally in time. A recent development in constitutive modeling allows us to simulate strain localization and densification in trabecular bone under large compressive strains without mesh dependence. The aim of this work was to validate this recently developed constitutive model of trabecular bone for the prediction of strain localization and densification in the human vertebral body subjected to large compressive deformation. A custom-made stepwise loading device mounted in a high resolution peripheral computer tomography system was used to describe the progressive collapse of 13 human vertebrae under axial compression. Continuum finite element analyses of the 13 compression tests were realized and the zones of high volumetric strain were compared with the experiments. A fair qualitative correspondence of the strain localization zone between the experiment and finite element analysis was achieved in 9 out of 13 tests and significant correlations of the volumetric strains were obtained throughout the range of applied axial compression. Interestingly, the stepwise propagating localization zones in trabecular bone converged to the buckling locations in the cortical shell. While the adopted continuum finite element approach still suffers from several limitations, these encouraging preliminary results towards the prediction of extended vertebral

  5. Applications of X-ray fluorescence holography to determine local lattice distortions

    International Nuclear Information System (INIS)

    Hayashi, Kouichi; Happo, Naohisa; Hosokawa, Shinya

    2014-01-01

    Highlights: • We summarized topics of X-ray fluorescence holography focused on the local lattice distortions. • We found details of behaviors of nearest neighbor atoms around dopants. • We found the average distributions of the atoms at the individual sites in mixed crystals. • Distorted and undistorted sires sometimes coexist in a same mixed crystal. - Abstract: X-ray fluorescence holography (XFH) is a method for investigating atomic order up to the medium ranges, and can provide 3D atomic images around specific elements within a radius of nm order. In addition to these characteristics, XFH is sensitive to positional fluctuations of atoms, and therefore it is useful for characterizing the local lattice distortions around specific elements. We have applied XFH to dopants and mixed crystals. We found interesting features in local lattice distortions, such as the displacements of first-neighbor atoms around dopants, far-sighted views of the atomistic fluctuations in mixed crystals, and the coexistence of distorted/undistorted sites in the same material

  6. Radioactivity of local tobacco and some selected brands of cigarettes

    International Nuclear Information System (INIS)

    Agba, E.H.; Kungur, S.T.; Akaagerger, N.S.

    2011-01-01

    This study investigated the radioactivity levels of locally consumed tobacco and three (3) popular brands of cigarettes. The Ortec X-ray fluorescence spectroscopy (XRF) with model number XL 12170 was used to determine the elemental composition of each of the samples. Also, the Scintillation detection method using a Model ST360 Radiation Counter was used to determine the mean activity levels of all the samples as well as a Radiation meter (Inspector 06250 Model) to determine the radiation exposure levels of the samples. Eleven (11) radioactive elements viz-K, Ca, Ti, Cr, Mn, Fe, Pb, Rb, Sr, Zr, and Nb were detected in both the tobacco and cigarettes samples. The locally consumed tobaccos were found to have a higher mean activity and radiation exposure levels than the selected brands of cigarettes.

  7. A study of trace elements in the atmosphere of PINSTECH, Nilore

    International Nuclear Information System (INIS)

    Rusheed, A.; Ahmed, S.; Mannan, A.; Qureshi, I. H.

    1987-06-01

    Atmospheric aerosol particulates of inorganic elements are usually transported to long distances from their source of emmision. The measurement of these elements in air provides useful information for understanding aerosol effects. Therefore studies were undertaken to determine the atmospheric concentration of some inorganic elements, 23 air filter samples of 24 hour duration were collected at Nilore, Islamabad area and analysed for 16 elements by neutron activation analysis (NAA). The concentration of 9 elements were determined in more than 12 samples. Comparison of the average concentration of these elements with those observed at other sites in U.S.A and U.K., indicate a distribution pattern similar to a non-urban site with very little pollution from industerial sources. Binary collection coefficients were calculated using the data of 9 principal elements of identify particulate sources. Co, Cr, Cs, Eu, Fe, Sc and Rb were assigned a crustal source, whereas Sb could possible has an anthropogenic source. Zn was found to have a constant nearby source the exact nature of which could be ascertained after a complete analysis of local soil and other possible sources near the site. (orign./A.B.)

  8. Determination of several trace elements in Chinese herbs with epithermal neutral activation analysis

    International Nuclear Information System (INIS)

    Chen, Chien-Yi; Chang Lai, Sheng-Pin

    2002-01-01

    For purpose of medication and health, Chinese herbs have been long adopted throughout oriental communities. Thus, more than ten trace elements in herbal medicines that are frequently consumed by children in central Taiwan were analyzed herein to explore the importance of various herbs. These elements are considered beneficial to human health in many folds. INAA was applied to determine the concentrations of elements as Al, Cl and Sc, while ENAA analyzed As, Cd, Mn, and Sb in this work. Among various local herbs, the elemental concentrations varied from 10 4 to 10 -3 μg/g. The experimental results suggest that the ENAA method can be applied successfully to analyze trace elements of As, Cd, Mn, and Sb in herbs. Yet, thirteen elements were verified, and a quantified index AT was introduced to help classifying the elements. The ATs in various Chinese herbs are also discussed herein and the accuracy is in excellent agreement with values reported in previously published data. (author)

  9. Determination of several trace elements in Chinese herbs with epithermal neutral activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chien-Yi [Chung Shan Medical Univ., Inst. of Biochemistry, Taiwan (China); Chang Lai, Sheng-Pin [Chung Shan Medical Univ. Hospital, Dept. of Nuclear Medicine Chief, Taiwan (China)

    2002-04-01

    For purpose of medication and health, Chinese herbs have been long adopted throughout oriental communities. Thus, more than ten trace elements in herbal medicines that are frequently consumed by children in central Taiwan were analyzed herein to explore the importance of various herbs. These elements are considered beneficial to human health in many folds. INAA was applied to determine the concentrations of elements as Al, Cl and Sc, while ENAA analyzed As, Cd, Mn, and Sb in this work. Among various local herbs, the elemental concentrations varied from 10{sup 4} to 10{sup -3} {mu}g/g. The experimental results suggest that the ENAA method can be applied successfully to analyze trace elements of As, Cd, Mn, and Sb in herbs. Yet, thirteen elements were verified, and a quantified index AT was introduced to help classifying the elements. The ATs in various Chinese herbs are also discussed herein and the accuracy is in excellent agreement with values reported in previously published data. (author)

  10. FINITE ELEMENT MODELING OF THIN CIRCULAR SANDWICH PLATES DEFLECTION

    Directory of Open Access Journals (Sweden)

    K. S. Kurachka

    2014-01-01

    Full Text Available A mathematical model of a thin circular sandwich plate being under the vertical load is proposed. The model employs the finite element method and takes advantage of an axisymmetric finite element that leads to the small dimension of the resulting stiffness matrix and sufficient accuracy for practical calculations. The analytical expressions for computing local stiffness matrices are found, which can significantly speed up the process of forming the global stiffness matrix and increase the accuracy of calculations. A software is under development and verification. The discrepancy between the results of the mathematical model and those of analytical formulas for homogeneous thin circularsandwich plates does not exceed 7%.

  11. Modeling the properties of closed-cell cellular materials from tomography images using finite shell elements

    International Nuclear Information System (INIS)

    Caty, O.; Maire, E.; Youssef, S.; Bouchet, R.

    2008-01-01

    Closed-cell cellular materials exhibit several interesting properties. These properties are, however, very difficult to simulate and understand from the knowledge of the cellular microstructure. This problem is mostly due to the highly complex organization of the cells and to their very fine walls. X-ray tomography can produce three-dimensional (3-D) images of the structure, enabling one to visualize locally the damage of the cell walls that would result in the structure collapsing. These data could be used for meshing with continuum elements of the structure for finite element (FE) calculations. But when the density is very low, the walls are fine and the meshes based on continuum elements are not suitable to represent accurately the structure while preserving the representativeness of the model in terms of cell size. This paper presents a shell FE model obtained from tomographic 3-D images that allows bigger volumes of low-density closed-cell cellular materials to be calculated. The model is enriched by direct thickness measurement on the tomographic images. The values measured are ascribed to the shell elements. To validate and use the model, a structure composed of stainless steel hollow spheres is firstly compressed and scanned to observe local deformations. The tomographic data are also meshed with shells for a FE calculation. The convergence of the model is checked and its performance is compared with a continuum model. The global behavior is compared with the measures of the compression test. At the local scale, the model allows the local stress and strain field to be calculated. The calculated deformed shape is compared with the deformed tomographic images

  12. Elemental analysis of Scottish populations of the ectoparasitic copepod Lepeophtheirus salmonis

    NARCIS (Netherlands)

    Shinn, A.P.; Bron, J.E.; Gray, D.J.; Sommerville, C.

    2000-01-01

    Conventional nebulisation ICPMS (Inductively Coupled Plasma Mass Spectrometry), was used to determine the concentration of a broad range of elements in the salmon louse Lepeophtheirus salmonis. Lice samples were collected from Atlantic salmon in seven localities (4 fish farms and 3 wild salmon

  13. Fuel element for nuclear reactors

    International Nuclear Information System (INIS)

    Cadwell, D.J.

    1982-01-01

    The invention concerns a fuel element for nuclear reactors with fuel rods and control rod guide tubes, where the control rod guide tubes are provided with flat projections projecting inwards, in the form of local deformations of the guide tube wall, in order to reduce the radial play between the control rod concerned and the guide tube, and to improve control rod movement. This should ensure that wear on the guide tubes is largely prevented which would be caused by lateral vibration of the control rods in the guide tubes, induced by the flow of coolant. (orig.) [de

  14. Local defect correction for boundary integral equation methods

    NARCIS (Netherlands)

    Kakuba, G.; Anthonissen, M.J.H.

    2013-01-01

    This paper presents a new approach to gridding for problems with localised regions of high activity. The technique of local defect correction has been studied for other methods as ¿nite difference methods and ¿nite volume methods. In this paper we develop the technique for the boundary element

  15. Operational Alignment in Predator Training Research

    Science.gov (United States)

    2014-04-21

    to the SO and, down the road, the Mission Intelligence Coordinator ( MIC ). 2. X-Plane 9 is COTS software and serves as the aeronautical simulation...uses to communicate with ground forces, command and control (C2) elements, and the Mission Intelligence Coordinator ( MIC ), among others. 10. LNCS...because key events can be scripted and initiated as appropriate, while distractor events like a villager walking around a market can be controlled by

  16. RESEARCH OF THE FOUNDATION CONSOLIDATED BY DIFFERENT-SIZED HORIZONTAL ELEMENTS

    Directory of Open Access Journals (Sweden)

    Isakova Elena Aleksandrovna

    2016-05-01

    Full Text Available The article is dedicated to the problem of geotechnics. The problems of the weak soil base are topical. Also there sometimes happen severe accidents of soil mass. A great number of such emergencies is of a progressive character, when a local crash leads to the crash of the whole construction. Tarring the soil with epoxy can ensure geotechnical safety of the basis. That’s why the improvement of this method is needed in order to reduce yielding of the base, create ground water cutoff or create building hoisting. In the article new structural solutions for reduction of settlement are presented. The authors suggest using the manufactured plane elements containing epoxy. Such elements have different sizes and lie underneath the foundation. Similar structural scheme can be used to reduce soil settlement. The authors carried out two series of plate-bearing model tests with manufactured plane epoxy elements. In the first series of tests the biggest element was closer to the foundation, the smallest element was closer to the biggest element. In the second series of tests the smallest element was closer to the foundation, the biggest element was closer to the smallest element. After the end of plate-bearing model tests the authors received values of the base settlement and the dependency diagrams “base settlement-soil pressure”. The new structural solution for reducing soil settlement proved to be effective. Settlement of base decreased sevenfold.

  17. Essential Boundary Conditions with Straight C1 Finite Elements in Curved Domains

    International Nuclear Information System (INIS)

    Ferraro, N.M.; Jardin, S.C.; Luo, X.

    2010-01-01

    The implementation of essential boundary conditions in C1 finite element analysis requires proper treatment of both the boundary conditions on second-order differentials of the solution and the curvature of the domain boundary. A method for the imposition of essential boundary conditions using straight elements (where the elements are not deformed to approximate a curved domain) is described. It is shown that pre-multiplication of the matrix equation by the local rotation matrix at each boundary node is not the optimal transformation. The uniquely optimal transformation is found, which does not take the form of a similarity transformation due to the non-orthogonality of the transformation to curved coordinates.

  18. Generic Regional Development Strategies from Local Stakeholders' Scenarios - an Alpine Village Experience

    Directory of Open Access Journals (Sweden)

    Wolfgang Loibl

    2010-09-01

    Full Text Available The article discusses the participatory elaboration of strategies for sustainable regional development in an Alpine tourist region in Austria to cope with global change effects evolving locally, considering climate change, economic change as well as (local societal change. Local stakeholders in an Alpine village in the Montafon region contributed in workshops to achieve the final results: participant teams conducted system analyses of the regional system to explore key elements of the region. Narrative scenarios described possible positive and negative development trends and indicated the critical issues controlling future development; 3D-images of landscape transition simulations show the consequences of certain development directions. Alternative development directions supported the local stakeholders to elaborate regional development strategies. In the end, the scientist team derived generic strategies for Alpine regions based on the locally developed strategy bundle. The article presents the intention, progress and outcome of the participatory approach and elaborates the potential to derive generic strategies from local ones and discusses the possibly occurring conflicts regarding cross-scale transfers of these local strategies. Overall, tourism was seen as a key element for future regional development, which can on the one hand derogate Alpine regions and is on the other hand threatened by climate change and diminution of landscape attractiveness. The suggested development strategies will help to cope with global change issues mitigating the negative consequences on the local society and environment.

  19. RNA localization in Xenopus oocytes uses a core group of trans-acting factors irrespective of destination.

    Science.gov (United States)

    Snedden, Donald D; Bertke, Michelle M; Vernon, Dominic; Huber, Paul W

    2013-07-01

    The 3' untranslated region of mRNA encoding PHAX, a phosphoprotein required for nuclear export of U-type snRNAs, contains cis-acting sequence motifs E2 and VM1 that are required for localization of RNAs to the vegetal hemisphere of Xenopus oocytes. However, we have found that PHAX mRNA is transported to the opposite, animal, hemisphere. A set of proteins that cross-link to the localization elements of vegetally localized RNAs are also cross-linked to PHAX and An1 mRNAs, demonstrating that the composition of RNP complexes that form on these localization elements is highly conserved irrespective of the final destination of the RNA. The ability of RNAs to bind this core group of proteins is correlated with localization activity. Staufen1, which binds to Vg1 and VegT mRNAs, is not associated with RNAs localized to the animal hemisphere and may determine, at least in part, the direction of RNA movement in Xenopus oocytes.

  20. Accuracy of finite-element models for the stress analysis of multiple-holed moderator blocks

    International Nuclear Information System (INIS)

    Smith, P.D.; Sullivan, R.M.; Lewis, A.C.; Yu, H.J.

    1981-01-01

    Two steps have been taken to quantify and improve the accuracy in the analysis. First, the limitations of various approximation techniques have been studied with the aid of smaller benchmark problems containing fewer holes. Second, a new family of computer programs has been developed for handling such large problems. This paper describes the accuracy studies and the benchmark problems. A review is given of some proposed modeling techniques including local mesh refinement, homogenization, a special-purpose finite element, and substructuring. Some limitations of these approaches are discussed. The new finite element programs and the features that contribute to their efficiency are discussed. These include a standard architecture for out-of-core data processing and an equation solver that operates on a peripheral array processor. The central conclusions of the paper are: (1) modeling approximation methods such as local mesh refinement and homogenization tend to be unreliable, and they should be justified by a fine mesh benchmark analysis; and (2) finite element codes are now available that can achieve accurate solutions at a reasonable cost, and there is no longer a need to employ modeling approximations in the two-dimensional analysis of HTGR fuel elements. 10 figures

  1. A Kohn–Sham equation solver based on hexahedral finite elements

    International Nuclear Information System (INIS)

    Fang Jun; Gao Xingyu; Zhou Aihui

    2012-01-01

    We design a Kohn–Sham equation solver based on hexahedral finite element discretizations. The solver integrates three schemes proposed in this paper. The first scheme arranges one a priori locally-refined hexahedral mesh with appropriate multiresolution. The second one is a modified mass-lumping procedure which accelerates the diagonalization in the self-consistent field iteration. The third one is a finite element recovery method which enhances the eigenpair approximations with small extra work. We carry out numerical tests on each scheme to investigate the validity and efficiency, and then apply them to calculate the ground state total energies of nanosystems C 60 , C 120 , and C 275 H 172 . It is shown that our solver appears to be computationally attractive for finite element applications in electronic structure study.

  2. Macrodystrophia lipomatosa: An unusual cause of localized gigantism

    Directory of Open Access Journals (Sweden)

    S Uma Maheswari

    2016-01-01

    Full Text Available Macrodystrophia lipomatosa (MDL is a rare congenital form of localized gigantism characterized by progressive overgrowth of all mesenchymal elements with a disproportionate increase in fibro adipose tissue. Here we report a case of 20 years old male who presented with history of painless gradual enlargement of entire left upper limb since childhood. Magnetic resonance imaging and histopathology confirmed the diagnosis of macrodystrophia lipomatosa. This condition has to be differentiated from other causes of localized gigantism, since these conditions differ in their course, prognosis, complications and treatment.

  3. Toxic trace element content of local fruits using instrumental neutron activation analysis (INAA)

    International Nuclear Information System (INIS)

    Siddique, N.; Ahmed, S.; Rahman, A; Waheed, S.; Chaudhary, M.M.; Qureshi, I.H.

    1997-01-01

    An important route of entry of environmental contaminants into the human system is through food intake. To study the effect of environmental pollution on the food chain, base line levels of toxic element content of commonly available food articles must be established. This study was undertaken to determine the toxic meal content of Pakistani fruits. The techniques of instrumental Neutron Activation Analysis (INAA) and Atomic Absorption Spectrometry (AAS) were employed for this purpose. Fourteen fruits apple, apricot, banana, data guava, kino, mango, melon, orange, peach, pear, plum, pomegranate and watermelon, as well as, the peels of apple and pear have been investigated and the results are discussed in this paper. The results were found to lie within 95 % confidence limit using Student's t test. Hg, As and Sb were detected, using INAA, in pear, pomegranate and water melon in low amounts (ppb levels) but were not detected in orange, plum and melon. Lesser amounts of toxic elements were detected in the peels of pear and high amounts were detected in apple peel as compared to the edible part of the fruit. Cadmium and lead were determined using Graphite Furnace atomic absorption Spectrometry. Cadmium was found to lie in the range of 18-42 ppb, in most fruits, whereas the amount of lead varied between 39-128 ppb. Lead was below detection limit in melon, guava, mango, and peach contained the highest amount of As, Cd, Hg and Pb. (author)

  4. Essential and toxic elements in seaweeds for human consumption.

    Science.gov (United States)

    Desideri, D; Cantaluppi, C; Ceccotto, F; Meli, M A; Roselli, C; Feduzi, L

    2016-01-01

    Essential elements (K, Ca, P, S, Cl, Mn, Fe, Cu, Zn, Ni, Br, and I) and nonessential or toxic elements (Al, Ti, Si, Rb, Sr, As, Cd, Sn, and Pb) were determined by energy-dispersive polarized x-ray fluorescence spectrometry in 14 seaweeds purchased in local specialty stores in Italy and consumed by humans. The differences in elements between the algae species reached up to 2-4 orders of magnitude. Lithothamnium calcareum showed the highest levels of Ca, Al, Si, Fe, and Ti. Palmaria palmata showed the highest concentrations of K, Rb, and Cl. The highest content of S was in Chondrus crispus. Laminaria digitata contained the highest concentrations of total As, Cd, Sn, Br, and I. The highest concentration of Zn was in Chlorella pyrenoidosa. Ulva lactuca displayed the highest levels of Cu, Ni, Mn, and Pb. Iodine levels ranged from 3.4 in Chlorella pyrenoidosa to 7316 mg/kg(dry) in Laminaria digitata. The nutrimental importance of essential elements was assessed using nutritional requirements. The results showed that the consumption of algae might serve as an important source of the essential elements. Health risk due to the toxic elements present in seaweed was estimated using risk estimators. Total As, Cd, and Pb concentrations ranged from <1 to 67.6, to 7.2 and to 6.7 mg/kg(dry) respectively; therefore, their contribution to total elemental intake does not appear to pose any threat to the consumers, but the concentrations of these elements should be controlled to protect the consumer against potential adverse health risks.

  5. A high-order multiscale finite-element method for time-domain acoustic-wave modeling

    Science.gov (United States)

    Gao, Kai; Fu, Shubin; Chung, Eric T.

    2018-05-01

    Accurate and efficient wave equation modeling is vital for many applications in such as acoustics, electromagnetics, and seismology. However, solving the wave equation in large-scale and highly heterogeneous models is usually computationally expensive because the computational cost is directly proportional to the number of grids in the model. We develop a novel high-order multiscale finite-element method to reduce the computational cost of time-domain acoustic-wave equation numerical modeling by solving the wave equation on a coarse mesh based on the multiscale finite-element theory. In contrast to existing multiscale finite-element methods that use only first-order multiscale basis functions, our new method constructs high-order multiscale basis functions from local elliptic problems which are closely related to the Gauss-Lobatto-Legendre quadrature points in a coarse element. Essentially, these basis functions are not only determined by the order of Legendre polynomials, but also by local medium properties, and therefore can effectively convey the fine-scale information to the coarse-scale solution with high-order accuracy. Numerical tests show that our method can significantly reduce the computation time while maintain high accuracy for wave equation modeling in highly heterogeneous media by solving the corresponding discrete system only on the coarse mesh with the new high-order multiscale basis functions.

  6. Is blade element momentum theory (BEM) enough for smart rotor design

    NARCIS (Netherlands)

    Yu, W.; Simao Ferreira, C.J.; van Kuik, G.A.M.

    2014-01-01

    Smart rotor emerges as an innovation technique to reduce the impact of dynamic loading on wind turbines. Local movements of distributed aerodynamic devices will enhance the non-uniformity and dynamic effects of loading, which will challenge the applicability of the blade element momentum theory

  7. Construction of local boundary conditions for an eigenvalue problem using micro-local analysis: application to optical waveguide problems

    International Nuclear Information System (INIS)

    Barucq, Helene; Bekkey, Chokri; Djellouli, Rabia

    2004-01-01

    We present a general procedure based on the pseudo-differential calculus for deriving artificial boundary conditions for an eigenvalue problem that characterizes the propagation of guided modes in optical waveguides. This new approach allows the construction of local conditions that (a) are independent of the frequency regime, (b) preserve the sparsity pattern of the finite element discretization, and (c) are applicable to arbitrarily shaped convex artificial boundaries. The last feature has the potential for reducing the size of the computational domain. Numerical results are presented to highlight the potential of conditions of order 1/2 and 1, for improving significantly the computational efficiency of finite element methods for the solution of optical waveguide problems

  8. Trace element composition of hair in the Italian population

    International Nuclear Information System (INIS)

    Clemente, G.F.; Cigna Rossi, L.

    1979-01-01

    The content of the trace elements Ag, Co, Cr, Cs, Fe, Hg, Ni, Rb, Sb, Sc, Se and Zn has been evaluated in hair samples collected from five different groups of subjects in Italy. All the measurements were performed by means of non-destructive neutron activation analysis of the hair samples that were carefully washed before analysis. In most of the samples the Cs, Rb and Sc content was below the detection limit of the analytical method. Each population group was formed of about five individuals of each sex, selected to be representative of the adult population living in a well-defined community. The five groups were chosen from distinct regions with different socio-economical living habits in order to detect the variability, if any, of the trace element burden among the Italian population. The trace element hair concentration of each subject was correlated with the trace element blood concentration and daily urinary excretion in order to differentiate the trace element content due to exogenous deposition on hair from that due to endogenous absorption routes. The results obtained show that the variability of the hair content among the various groups is strongly linked to local environmental factors. The histograms of the individual values of the hair concentration are given for all trace elements measured, together with a statistical analysis of all data. (author)

  9. Oleotourism: Local Actors for Local Tourism Development

    Directory of Open Access Journals (Sweden)

    Marco Tregua

    2018-05-01

    Full Text Available Olive oil consumption has grown substantially in recent years, due in part to the fact that olive oil is healthy. Much of the global olive oil production comes from the rural areas of Jaén in southern Spain. Surrounding this industry, services such as oleotourism are increasing. This paper aims to identify the key elements supporting the development of oleotourism. After a preliminary exploratory analysis of the existing data, a qualitative analysis was performed with actors directly involved in the industry in Jaén. The results helped us define the level of the stakeholders’ involvement and the sustainability, the opportunities, and the constraints affecting oleotourism in this area. The practical implications of this investigation can be useful for governing agencies, local firms, and the tourism industry in support of oleotourism development.

  10. Development of local shear bands and orientation gradients in fcc polycrystals

    International Nuclear Information System (INIS)

    Beaudoin, A.J. Jr.; Mecking, H.; Kocks, U.F.

    1995-01-01

    A finite element formulation which derives constitutive response from crystal plasticity theory is used to examine localized deformation in fcc polycrystals. The polycrystals are simple, idealized arrangements of grains. Localized deformations within individual grains lead to the development of domains that are separated by boundaries of high misorientation. Shear banding is seen to occur on a microscopic scale of grain dimensions. The important consequences of these simulations are that the predicted local inhomogeneities are meeting various requirements which make them possible nucleation sites for recrystallization

  11. Low frequency torsional vibration gaps in the shaft with locally resonant structures

    International Nuclear Information System (INIS)

    Yu Dianlong; Liu Yaozong; Wang Gang; Cai Li; Qiu Jing

    2006-01-01

    The propagation of torsional wave in the shaft with periodically attached local resonators is studied with the transfer matrix theory and the finite element method. The analytical dispersion relation and the complex band structure of such a structure is presented for the first time, which indicates the existence of low frequency gaps. The effect of shaft material on the vibration attenuation in band gap is investigated. The frequency response function of the shaft with finite periodic locally resonant oscillators is simulated with finite element method, which shows large vibration attenuation in the frequency range of the gap as expected. The low frequency torsional gap in shafts provides a new idea for vibration control

  12. Analysis of elemental composition of porcelains unearthed from Waguantan kiln site by PIXE–RBS

    International Nuclear Information System (INIS)

    Zhou, Z.; Zhang, K.; Xia, C.D.; Liu, M.T.; Zhu, J.J.; An, Z.; Bai, B.

    2015-01-01

    Highlights: •We analyzed 61 unearthed porcelain shards in Yuan Dynasty by PIXE–RBS. •An electron gun was installed to solve the electric charge accumulations. •The factor analysis was performed for the element compositions. •The “exotic group” porcelain samples unearthed were produced locally. -- Abstract: A method combining proton-induced X-ray emission spectrometry (PIXE) and Rutherford backscattering spectrometry (RBS) was used to determine the composition of 61 porcelain shards from the Yuan Dynasty (1271–1368 A.D.) unearthed from the Waguantan kiln site at Tianzhu County in Guizhou Province, China. Based on our previous experimental setup, an electron gun device with a LaB 6 crystal cathode was installed to solve the problem created when the incident proton beams generated electric charge accumulations on the surfaces of the insulating porcelain samples, which induced a large bremsstrahlung background. The use of the electron gun has largely eliminated the large bremsstrahlung background and has therefore improved the detection limits for elements, especially for trace elements, and made it possible to determine the origin of the porcelains based on the trace elements. Major and trace elemental compositions of the porcelain bodies and glazes measured by PIXE and RBS were analyzed by the factor analysis method. The factor analysis showed that a few pieces of porcelain with a style similar to the porcelain of the Longquan kiln among the unearthed porcelains from the Waguantan kiln site did not have obvious differences in elemental compositions from other remaining porcelains unearthed from the Waguantan kiln site, indicating that the pieces of unearthed porcelain with the Longquan kiln style did in fact belong to the product fired locally by imitating the model of the Longquan celadon with local raw materials. This result therefore indicated that the Longquan kiln technology that originated from the Five Dynasties (907–960 A.D.) had been

  13. Analysis of elemental composition of porcelains unearthed from Waguantan kiln site by PIXE–RBS

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Z. [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 (China); Zhang, K. [School of History and Culture, Sichuan University, Chengdu 610064 (China); Xia, C.D.; Liu, M.T.; Zhu, J.J. [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 (China); An, Z., E-mail: anzhu@scu.edu.cn [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 (China); Bai, B., E-mail: baibin@scu.edu.cn [School of History and Culture, Sichuan University, Chengdu 610064 (China)

    2015-03-01

    Highlights: •We analyzed 61 unearthed porcelain shards in Yuan Dynasty by PIXE–RBS. •An electron gun was installed to solve the electric charge accumulations. •The factor analysis was performed for the element compositions. •The “exotic group” porcelain samples unearthed were produced locally. -- Abstract: A method combining proton-induced X-ray emission spectrometry (PIXE) and Rutherford backscattering spectrometry (RBS) was used to determine the composition of 61 porcelain shards from the Yuan Dynasty (1271–1368 A.D.) unearthed from the Waguantan kiln site at Tianzhu County in Guizhou Province, China. Based on our previous experimental setup, an electron gun device with a LaB{sub 6} crystal cathode was installed to solve the problem created when the incident proton beams generated electric charge accumulations on the surfaces of the insulating porcelain samples, which induced a large bremsstrahlung background. The use of the electron gun has largely eliminated the large bremsstrahlung background and has therefore improved the detection limits for elements, especially for trace elements, and made it possible to determine the origin of the porcelains based on the trace elements. Major and trace elemental compositions of the porcelain bodies and glazes measured by PIXE and RBS were analyzed by the factor analysis method. The factor analysis showed that a few pieces of porcelain with a style similar to the porcelain of the Longquan kiln among the unearthed porcelains from the Waguantan kiln site did not have obvious differences in elemental compositions from other remaining porcelains unearthed from the Waguantan kiln site, indicating that the pieces of unearthed porcelain with the Longquan kiln style did in fact belong to the product fired locally by imitating the model of the Longquan celadon with local raw materials. This result therefore indicated that the Longquan kiln technology that originated from the Five Dynasties (907–960 A.D.) had been

  14. AMP deaminase histochemical activity and immunofluorescent isozyme localization in rat skeletal muscle

    Science.gov (United States)

    Thompson, J. L.; Sabina, R. L.; Ogasawara, N.; Riley, D. A.

    1992-01-01

    The cellular distribution of AMP deaminase (AMPda) isozymes was documented for rat soleus and plantaris muscles, utilizing immunofluorescence microscopy and immunoprecipitation methods. AMPda is a ubiquitous enzyme existing as three distinct isozymes, A, B and C, which were initially purified from skeletal muscle, liver (and kidney), and heart, respectively. AMPda-A is primarily concentrated subsarcolemmally and intermyofibrillarly within muscle cells, while isozymes B and C are concentrated within non-myofiber elements of muscle tissue. AMPda-B is principally associated with connective tissues surrounding neural elements and the muscle spindle capsule, and AMPda-C is predominantly associated with circulatory elements, such as arterial and venous walls, capillary endothelium, and red blood cells. These specific localizations, combined with documented differences in kinetic properties, suggest multiple functional roles for the AMPda isozymes or temporal segregation of similar AMPda functions. Linkage of the AMPda substrate with adenosine production pathways at the AMP level and the localization of isozyme-C in vascular tissue suggest a regulatory role in the microcirculation.

  15. Local chemistry of Al and P impurities in silica

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Stokbro, Kurt

    2000-01-01

    The local structure around Al and P impurities in silica is investigated using density-functional theory. Two distinct cases are considered: impurities substituting for a Si atom in alpha quartz, and impurities implanted in a stoichiometric alpha-quartz crystal. Both impurity elements are found t...

  16. Heavy element affinities in Apollo 17 samples

    International Nuclear Information System (INIS)

    Allen, R.O. Jr.; Jovanovic, S.; Reed, G.W. Jr.

    1975-01-01

    204 Pb, Bi, Tl and Zn in samples from Apollo 17 exhibit relationships not found in samples from other sites. 204 Pb, Tl and Zn in residues remaining after dilute acid leaching are correlated with one another. Orange soil 74220, which is enriched in 204 Pb, Tl and Zn, is included in these relationships. In addition the submicron metallic phase generally associated with agglutinate formation is correlated with all three of these elements; this relationship has already been reported for 204 Pb in other samples. Thus, orange soil and agglutinates appear to be involved in concentrating heavy volatile metals. A process other than mixing is required to account for this. As a consequence of the isolation of the landing site by the surrounding massifs, local supply and recycling of volatile trace elements in soils may account for some of the interelement relations. (Auth.)

  17. Complete Subsurface Elemental Composition Measurements With PING

    Science.gov (United States)

    Parsons, A. M.

    2012-01-01

    The Probing In situ with Neutrons and Gamma rays (PING) instrument will measure the complete bulk elemental composition of the subsurface of Mars as well as any other solid planetary body. PING can thus be a highly effective tool for both detailed local geochemistry science investigations and precision measurements of Mars subsurface reSOurces in preparation for future human exploration. As such, PING is thus fully capable of meeting a majority of both ncar and far term elements in Challenge #1 presented for this conference. Measuring the ncar subsurface composition of Mars will enable many of the MEPAG science goals and will be key to filling an important Strategic Knowledge Gap with regard to In situ Resources Utilization (ISRU) needs for human exploration. [1, 2] PING will thus fill an important niche in the Mars Exploration Program.

  18. Neural correlates of conflict control on facial expressions with a flanker paradigm.

    Science.gov (United States)

    Liu, Tongran; Xiao, Tong; Shi, Jian-Nong

    2013-01-01

    Conflict control is an important cognitive control ability and it is also crucial for human beings to execute conflict control on affective information. To address the neural correlates of cognitive control on affective conflicts, the present study recorded event-related potentials (ERPs) during a revised Eriksen Flanker Task. Participants were required to indicate the valence of the central target expression while ignoring the flanker expressions in the affective congruent condition, affective incongruent condition and neutral condition (target expressions flanked by scramble blocks). Behavioral results manifested that participants exhibited faster response speed in identifying neutral target face when it was flanked by neutral distractors than by happy distractors. Electrophysiological results showed that happy target expression induced larger N2 amplitude when flanked by sad distractors than by happy distractors and scramble blocks during the conflict monitoring processing. During the attentional control processing, happy target expression induced faster P3 response when it was flanked by happy distractors than by sad distractors, and sad target expression evoked larger P3 amplitude when it was flanked by happy distractors comparing with sad distractors. Taken together, the current findings of temporal dynamic of brain activity during cognitive control on affective conflicts shed light on the essential relationship between cognitive control and affective information processing.

  19. Neural correlates of conflict control on facial expressions with a flanker paradigm.

    Directory of Open Access Journals (Sweden)

    Tongran Liu

    Full Text Available Conflict control is an important cognitive control ability and it is also crucial for human beings to execute conflict control on affective information. To address the neural correlates of cognitive control on affective conflicts, the present study recorded event-related potentials (ERPs during a revised Eriksen Flanker Task. Participants were required to indicate the valence of the central target expression while ignoring the flanker expressions in the affective congruent condition, affective incongruent condition and neutral condition (target expressions flanked by scramble blocks. Behavioral results manifested that participants exhibited faster response speed in identifying neutral target face when it was flanked by neutral distractors than by happy distractors. Electrophysiological results showed that happy target expression induced larger N2 amplitude when flanked by sad distractors than by happy distractors and scramble blocks during the conflict monitoring processing. During the attentional control processing, happy target expression induced faster P3 response when it was flanked by happy distractors than by sad distractors, and sad target expression evoked larger P3 amplitude when it was flanked by happy distractors comparing with sad distractors. Taken together, the current findings of temporal dynamic of brain activity during cognitive control on affective conflicts shed light on the essential relationship between cognitive control and affective information processing.

  20. Perceptual load vs. dilution: the roles of attentional focus, stimulus category, and target predictability.

    Science.gov (United States)

    Chen, Zhe; Cave, Kyle R

    2013-01-01

    Many studies have shown that increasing the number of neutral stimuli in a display decreases distractor interference. This result has been interpreted within two different frameworks; a perceptual load account, based on a reduction in spare resources, and a dilution account, based on a degradation in distractor representation and/or an increase in crosstalk between the distractor and the neutral stimuli that contain visually similar features. In four experiments, we systematically manipulated the extent of attentional focus, stimulus category, and preknowledge of the target to examine how these factors would interact with the display set size to influence the degree of distractor processing. Display set size did not affect the degree of distractor processing in all situations. Increasing the number of neutral items decreased distractor processing only when a task induced a broad attentional focus that included the neutral stimuli, when the neutral stimuli were in the same category as the target and distractor, and when the preknowledge of the target was insufficient to guide attention to the target efficiently. These results suggest that the effect of neutral stimuli on the degree of distractor processing is more complex than previously assumed. They provide new insight into the competitive interactions between bottom-up and top-down processes that govern the efficiency of visual selective attention.

  1. New functionalities in abundant element oxides: ubiquitous element strategy

    International Nuclear Information System (INIS)

    Hosono, Hideo; Hayashi, Katsuro; Kamiya, Toshio; Atou, Toshiyuki; Susaki, Tomofumi

    2011-01-01

    While most ceramics are composed of ubiquitous elements (the ten most abundant elements within the Earth's crust), many advanced materials are based on rare elements. A 'rare-element crisis' is approaching owing to the imbalance between the limited supply of rare elements and the increasing demand. Therefore, we propose a 'ubiquitous element strategy' for materials research, which aims to apply abundant elements in a variety of innovative applications. Creation of innovative oxide materials and devices based on conventional ceramics is one specific challenge. This review describes the concept of ubiquitous element strategy and gives some highlights of our recent research on the synthesis of electronic, thermionic and structural materials using ubiquitous elements. (topical review)

  2. The optimum shielding for a power reactor using local components

    International Nuclear Information System (INIS)

    AlHajali, S.; Kharita, M. H.; Yousef, S.; Naoom, B.; Al-Nassar, M.

    2009-07-01

    Some local concrete mixtures have been picked out (selected) to be studied as shielding concrete for prospective nuclear power reactor in Syria. This research has interested in the attenuation of gamma radiation and neutron fluxes by these local concretes in the ordinary conditions. In addition to the heat effect on the shielding and physical properties of local concrete. Furthermore the neutron activation of the elements of the local concrete mixtures have been studied that for selection the low-activation materials (low dose rate and short half life radioisotopes). In this way biological shielding for nuclear reactor can be safe during operation of nuclear power reactor, in addition to be low radioactive waste after decommissioning the reactor. (author)

  3. Local stress calculation in simulations of multicomponent systems

    International Nuclear Information System (INIS)

    Branicio, Paulo S.; Srolovitz, David J.

    2009-01-01

    The virial and Hardy methods provide accurate local stresses for single component materials such as monatomic metals. In contrast to the elemental material case, both methods provide poor estimates of the local stress for multicomponent materials. Using binary materials such as CaO, SiC and AlN and homogeneous strain, we demonstrate that there are several sources for the slow convergence of the virial and Hardy local stresses to the bulk values. Different approaches such as enforced stoichiometry, atomic localization functions and the atomic voronoi volume are used to improve the convergence and increase the spatial resolution of the local stress. The virial method with enforced stoichiometry and atomic voronoi volumes is the most accurate, giving exact stress values by the first atomic shell. In the general case, not assuming stoichiometry, the virial method with localization functions converge to 93% of the bulk value by the third atomic shell. This work may be particularly useful for the real-time description of stresses in simulations of shock waves and deformation dynamics.

  4. Where and how morphologically complex words interplay with naming pictures.

    Science.gov (United States)

    Zwitserlood, Pienie; Bölte, Jens; Dohmes, Petra

    2002-01-01

    Two picture-word experiments are reported in which a delay of 7 to 10 was introduced between distractor and picture. Distractor words were either derived words (Experiment 1) or compounds (Experiment 2), morphologically related to the picture name. In both experiments, the position of morphological overlap between distractor (e.g., rosebud vs tea-rose) and picture name (rose) was manipulated. Clear facilitation of picture naming latencies was obtained when pictures were paired with morphological distractors, and effects were independent of distractor type and position of overlap. The results are evaluated against "full listing" and "decomposition" approaches of morphological representation. Copyright 2002 Elsevier Science (USA).

  5. Environmental mineralogy - Understanding element behavior in ecosystems

    International Nuclear Information System (INIS)

    Brown Jr, G.E.; Calas, G.

    2011-01-01

    Environmental Mineralogy has developed over the past decade in response to the recognition that minerals are linked in many important ways with the global ecosystem. Minerals are the main repositories of the chemical elements in Earth's crust and thus are the main sources of elements needed for the development of civilization, contaminant and pollutant elements that impact global and local ecosystems, and elements that are essential plant nutrients. These elements are released from minerals through natural processes, such as chemical weathering, and anthropogenic activities, such as mining and energy production, agriculture and industrial activities, and careless waste disposal. Minerals also play key roles in the biogeochemical cycling of the elements, sequestering elements and releasing them as the primary minerals in crustal rocks undergo various structural and compositional transformations in response to physical, chemical, and biological processes that produce secondary minerals and soils. These processes have resulted in the release of toxic elements such as arsenic in groundwater aquifers, which is having a major impact on the health of millions of people in South and Southeast Asia. The interfaces between mineral surfaces and aqueous solutions are the locations of most chemical reactions that control the composition of the natural environment, including the composition of natural waters. The nuclear fuel cycle, from uranium mining to the disposition of high-level nuclear waste, is also intimately related to minerals. A fundamental understanding of these processes requires molecular-scale information about minerals, their bulk structures and properties such as solubility, their surfaces, and their interactions with aqueous solutions, atmospheric and soil gases, natural organic matter, and biological organisms. Gaining this understanding is further complicated by the presence of natural, incidental, and manufactured nano-particles in the environment, which

  6. Finite Element Calculation of Local Variation in the Driving Force for Austenite to Martensite Transformation

    International Nuclear Information System (INIS)

    Datta, K.; Geijselaers, H. J. M.; Huetink, J.; Post, J.; Dinsdale, A.

    2007-01-01

    The mechanics and thermodynamics of strain induced martensitic transformation are coupled for a metastable alloy steel and implemented in FE models of forming processes. The basic formulations are based on a fifty year old treaty by Patel and Cohen. The variation in Gibbs energy due to local variation in strain, strain rate, temperature and state of stress of a forming part is calculated by FE codes. The local variation in Gibbs energy gives a probabilistic image of the potential sites for strain induced martensitic transformations

  7. Telework centers as local development

    OpenAIRE

    Lorentzen, Anne

    2013-01-01

    This paper discusses the establishment of distant work centers as an element in local development strategies in rural areas with a particular view on two new telework centers in Region North DenmarkDistant work is a phenomenon on the rise, due to the development of the internet on the one hand and new flexible work functions on the other hand. Not only the exchange of documents, but also meetings can be organized virtually by still better video conference equipment and programs. An implicatio...

  8. Study of trace elements in milk by nuclear analytical techniques

    Energy Technology Data Exchange (ETDEWEB)

    Gharib, A.; Rahimi, H.; Peyrovan, H.; Raofei, H.N.J.; Taherpour, H. (Atomic Energy Organization of Iran, Teheran. Nuclear Research Centre)

    This work is part of a project with the IAEA, in a coordinated programme on ''trace elements in Human Nutrition and Bio-Environmental Systems'' to evaluate their nutritional requirements, interrelations and the role of trace elements in health, metabolism etc. Cow's milk is regarded as one of the most important and nutritious foodstuffs consumed by people. Hence, as a first step, an elemental analysis for milk was carried out for this purpose so a few samples of pasteurized milk and local samples were investigated for essential and toxic trace elements. The secondary aim of this project was the assessment of various analytical techniques involved. However, in the present work, the methods involved were AAS, PIXE and NAA. The latter method applied, both instrumentally and radiochemically. Although the results pertaining to the various methods employed are not in good agreement, there is however, some justification to clarify this internal inconsistency. The precision for NAA and AAS allows greater degree of acceptance respectively. Although PIXE is very fast and rather routine, the technique of trace element analysis needs certain adaptations and developments.

  9. THE VOCATIONAL EDUCATION AND TRAINING CENTERS: AN ALTERNATIVE TO LOCAL DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Vicente Palop-Esteban

    2014-06-01

    Full Text Available This paper presents an educational proposal of a technical nature but with bases rooted in popular education (Freire, 1970. It aims to provide lights on how vocational education, could have a link to the local development of the territory. Local development has its maximum exponents in the fields of the recovery of the endogenous sources and in the articulation of the associative network (Herrera, 2009, with the consequent benefit of enhancing participatory instruments that improve the democratic exchanges of territory. The educative centers may have a privileged territory view, converge in the same few elements, actors and actresses key, also if the Centre has the role of formative work development from the articulation of the productive elements, we have a resource of excellent characteristics for local development. The proposal is therefore, the linkage of the Centers for education and work with a perspective of local development, especially in areas with low social structuring communities, i.e., high rates of unemployment, schooling, economic difficulties, etc. These scenarios are very common in urban peripheries both in Europe and in America, but these fields, can also be found in certain rural communities, Latin American, although with different characteristics. The incidence in the local promotion, in these cases, will have a special responsibility, since the work by the unfinished schooling and educational inclusion, without doubt, work for community development (Torrent, 2012.

  10. The study of trace elements in milk by nuclear analytical techniques

    International Nuclear Information System (INIS)

    Gharib, A.; Rahimi, H.; Peyrovan, H.; Raofei, H.N.J.; Taherpour, H.

    1983-01-01

    This work is part of a project with the IAEA, in a coordinated programme on ''Trace Elements in Human Nutrition and Bio-Environmental Systems'' to evaluate their nutritional requirements, interrelations and the role of Trace Elements in health, metabolism etc. Cow's milk being regarded as one of the most important and nutritious foodstuffs consumed by people. Hence as a first step, an elemental analysis for milk was carried out for this purpose so a few samples of pasteurized milk and local samples were investigated for essential and toxic trace elements. The secondary aim of this project was the assessment of various analytical techniques involved. However, in the present work, the methods involved were AAS, PIXE and NAA. The latter method applied, both instrumentally and radiochemically. Although the results pertaining to the various methods employed are not in good agreement, there is however, some justification to clarify this internal inconsistency. The precision for NAA and AAS allows greater degree of acceptance respectively. Although PIXE is a very fast and rather a routine but the technique of trace element analysis needs certain adaptations and developments

  11. Being connected to the local community through a Festival mobile application

    Energy Technology Data Exchange (ETDEWEB)

    Han, Kyungsik; Wirth, Richard; Hanrahan, Benjamin; Chen, Jiawei; Lee, Sooyeon; Carroll, John M.

    2016-04-25

    In this paper we report our investigation into how using and interacting with a local festival mobile app enhanced users’ festival experiences and connected them to other local users and their community. We explored the relationship between users’ perceived basic affordances of mobile technology, perceived opportunities of the festival app, and three elements that sustain the local community — attachment, engagement, and social support networks. Based on the usage logs of 348 active users, as well as survey responses from 80 users, we present a mobile-mediated local community framework and found that engagement is a key mediator of mobile experiences and facets of community.

  12. Adaptive Multilevel Methods with Local Smoothing for $H^1$- and $H^{\\mathrm{curl}}$-Conforming High Order Finite Element Methods

    KAUST Repository

    Janssen, Bä rbel; Kanschat, Guido

    2011-01-01

    A multilevel method on adaptive meshes with hanging nodes is presented, and the additional matrices appearing in the implementation are derived. Smoothers of overlapping Schwarz type are discussed; smoothing is restricted to the interior of the subdomains refined to the current level; thus it has optimal computational complexity. When applied to conforming finite element discretizations of elliptic problems and Maxwell equations, the method's convergence rates are very close to those for the nonadaptive version. Furthermore, the smoothers remain efficient for high order finite elements. We discuss the implementation in a general finite element code using the example of the deal.II library. © 2011 Societ y for Industrial and Applied Mathematics.

  13. Relevance-based control over visual attention is fast and interdependent with stimulus-driven capture

    DEFF Research Database (Denmark)

    Nordfang, Maria; Bundesen, Claus

    2012-01-01

    or distractor) was a color singleton, but the probability that the singleton was a target was just the same as the probability that a nonsingleton was a target. Participants showed significant effects of both feature contrast and task relevance. The probability of correctly reporting a singleton target...... that high local feature contrast attracts attention independently of task-relevance. Yet, recent studies have provided evidence that effects of task-irrelevant feature contrast interact with the task-relevance of the object in question (Nordfang, 2011). In a new experiment, display size was kept constant...... was significantly higher than the probability of reporting a nonsingleton target. The probability of correctly reporting a given target also was significantly higher for the displays with 2 targets and 6 distractors than for the 8-target displays, revealing selectivity based on task-relevance. This effect...

  14. High-resolution seismic wave propagation using local time stepping

    KAUST Repository

    Peter, Daniel

    2017-03-13

    High-resolution seismic wave simulations often require local refinements in numerical meshes to accurately capture e.g. steep topography or complex fault geometry. Together with explicit time schemes, this dramatically reduces the global time step size for ground-motion simulations due to numerical stability conditions. To alleviate this problem, local time stepping (LTS) algorithms allow an explicit time stepping scheme to adapt the time step to the element size, allowing nearoptimal time steps everywhere in the mesh. This can potentially lead to significantly faster simulation runtimes.

  15. TRANSPARENCY OF LOCAL BUDGETS IN THE NORTH-WEST REGION OF ROMANIA

    Directory of Open Access Journals (Sweden)

    Pintea Mirela-Oana

    2013-07-01

    Full Text Available The central researched element in our paper is the local budgets, the basic component of local public finances. Local budgets, like any other budgets, are the most important tool for the management (of local governments planning, forecasting, implementing and monitoring the results of administrative-territorial units activity, also being an appropriate tool for enhancing performance. A budget is the government's plan regarding the use of public resources to meet the citizens' needs. The aim of this paper is to realize a research on budget transparency in local governments from the Nord-West Region of Romania, regarding the availability of the budget information on the websites of the county councils and the county residences. The key element of good governance in today global economic environment is transparency that can be defined as the openness of public authorities (central and local regarding their policy intention, formulation and implementation. For local governments budget transparency is an important issue, due to the growing role of administrative-territorial units, confirmed over time by the economic reality. The importance of local budgets has increased in recent years due to the need to improve management efficiency and accounting al the level of local governments. Not only policy makers but also the citizens need information regarding local government current activities, expenditures, development projects and policies. In this context of a growing need for information, the transparency of local budgets is a mandatory condition for any local government. The combination of budget transparency and public participation in budget processes has the potential to combat corruption, foster public accountability of government agencies and contribute to judicious use of public funds. In this context, budget transparency represents the mean through which ordinary citizens and civil society organizations can access information about the

  16. Development of Management, Child Development Centers Organization rule Local Government in Udon thani

    OpenAIRE

    Suriya Sukram; Chaiyot Ruangsuwan

    2017-01-01

    This research aims to study the composition and indications 1. The Child Development Centre under the local governments in UdonThani province 2. Study the current state and the desired operating child care centers under the jurisdiction of local governments in UdonThani province. 3. Develop the child development centers under the local governments in UdonThani province. The operation is divided. Phase one of the elements and indicators, the Child Development Center. By synthesi...

  17. New nuclear plant development - balancing localization with competitiveness

    International Nuclear Information System (INIS)

    Caplan, M.; Thompson, T.S.

    2014-01-01

    Nuclear power plants are large infrastructure projects that require government support and approval. This paper will highlight and contrast the larger, mostly government-desired, nuclear program localization objectives with the more utility-specific requirements for successful project implementation. Governments are concerned about sustainable industrial development, particularly manufacturing, and job creation while utilities are focused on delivering reliable electricity to consumers at the lowest cost. Numerous countries emphasize local content as a key requirement when procuring a station. For countries like China and Korea that have large programs, their strategy has been to localize to the point of having their own indigenous design. However, developing a workable localization strategy that truly benefits the local economy for others including existing nuclear markets like Canada, the UK, South Africa and Brazil as well as in newly developing markets such as Vietnam and Malaysia is more challenging. These countries may not look to indigenize a new design, rather they would localize elements of the nuclear program that best fit their strengths. The paper will discuss the issues related to developing successful localization and industrialization strategies in a changing nuclear world. (author)

  18. New nuclear plant development - balancing localization with competitiveness

    Energy Technology Data Exchange (ETDEWEB)

    Caplan, M.; Thompson, T.S. [MZ Consulting Inc., ON (Canada)

    2014-07-01

    Nuclear power plants are large infrastructure projects that require government support and approval. This paper will highlight and contrast the larger, mostly government-desired, nuclear program localization objectives with the more utility-specific requirements for successful project implementation. Governments are concerned about sustainable industrial development, particularly manufacturing, and job creation while utilities are focused on delivering reliable electricity to consumers at the lowest cost. Numerous countries emphasize local content as a key requirement when procuring a station. For countries like China and Korea that have large programs, their strategy has been to localize to the point of having their own indigenous design. However, developing a workable localization strategy that truly benefits the local economy for others including existing nuclear markets like Canada, the UK, South Africa and Brazil as well as in newly developing markets such as Vietnam and Malaysia is more challenging. These countries may not look to indigenize a new design, rather they would localize elements of the nuclear program that best fit their strengths. The paper will discuss the issues related to developing successful localization and industrialization strategies in a changing nuclear world. (author)

  19. Determination of toxic and essential elements in foodstuffs from local market in Jakarta

    International Nuclear Information System (INIS)

    Sadjirun, S.

    1994-01-01

    This report presents data on toxic and essential elements such as As, Cd, Cr, Cu, Hg, Pb, Sb, Se, and Zn in rice, corn, bean, wheat, small green pea, vegetables, fruits, tea, coffee, sea foods, meat, chicken, intestines and associated organs, and eggs as consumed in Jakarta. As, Hg, Sb, Cr, Se, and Zn were determined using instrumental neutron activation analysis (INAA) after being irradiated at TRIGA MARK II reactor, while Cd, Cu, and Pb were determined using atomic absorption spectrometry (AAS). The results obtained were lower than the maximum permissible concentrations allowed. (author). 6 refs, 9 tabs

  20. The role of high-energy synchrotron radiation in biomedical trace element research

    International Nuclear Information System (INIS)

    Pounds, J.G.; Long, G.J.; Kwiatek, W.M.; Jones, K.W.; Gordon, B.M.; Hanson, A.L.

    1987-01-01

    This paper will present the results of an investigation of the distribution of essential elements in the normal hepatic lobule. the liver is the organ responsible for metabolism and storage of most trace elements. Although parenchymal hepatocytes are rather uniform histologically, morphometry, histochemistry, immunohistochemistry, and microdissection with microchemical investigations have revealed marked heterogeneity on a functional and biochemical level. Hepatocytes from the periportal and perivenous zones of the liver parrenchyma differ in oxidative energy metabolism, glucose uptake and output, unreagenesis, biotransformation, bile acid secretion, and palsma protein synthesis and secretion. Although trace elements are intimately involved in the regulation and maintenance of these functions, little is known regarding the heterogeneity of trace element localization of the liver parenchyma. Histochemical techniques for trace elements generally give high spatial resolution, but lack specificity and stoichiometry. Microdissection has been of marginal usefulness for trace element analyses due to the very small size of the dissected parenchyma. The characteristics of the high-energy x-ray microscope provide an effective approach for elucidating the trace element content of these small biological structures or regions. 5 refs., 1 fig., 1 tab