Sample records for cued lever-press task

  1. Striatal dopamine release in the rat during a cued lever-press task for food reward and the development of changes over time measured using high-speed voltammetry. (United States)

    Nakazato, Taizo


    Substantia nigra dopamine neuronal activity in the primate is thought to be related to the error in predicting reward delivery. Dopamine release in rat nucleus accumbens has been shown to increase in relation to drug/food-seeking behaviour. It is not known how the release of dopamine in the striatum corresponds to the many distinct steps of a rewarded, cued task (e.g. recognizing the cue, executing the behaviour, anticipating the reward, receiving the reward) and how dopamine release then changes over time as task performance improves. To investigate dopamine release during a rewarded, cued task and the development of changes in dopamine release over time, changes in extracellular striatal dopamine concentration during a rewarded, cued lever-press task were measured a few days every week for 5 months using high-speed in vivo voltammetry. Rats were trained to press a lever after a tone to obtain a food reward. The reaction time for the lever press decreased gradually as training continued. Changes in dopamine concentration were measured in the anterior striatum (ventral portion) during the task performance after an initial 6-day familiarization period, in which the animals learned that a lever press yielded food, and a 5-week period for surgery, recovery, and electrode preparation. During the task performance, dopamine concentration started to increase just after the cue, peaked near the time of the lever press, and returned to basal levels 1-2 s after the lever press. This pattern of changes in dopamine concentration was observed over the 5 months of testing, the peak dopamine concentration increasing steadily until peaking at week 7, at which time the task performance had not yet improved significantly from week 2. By week 13, task performance had significantly improved and peak dopamine concentration had begun to subside. Thus, the increase in dopamine concentration after the cue was highest while the task was not yet perfected and subsided toward the end of the

  2. Differential Suppression by Punishment of Nonconsummatory Licking and Lever Pressing (United States)

    Walters, Gary C.; Herring, Barbara


    Five experiments investigated the differential effects of shock punishment on nonconsummatory licking (dry licking) and lever pressing. Results support a motivationally based theory of punishment involving the role of incentive stimuli associated with the particular responses studied. (Editor/RK)

  3. Effects of prenatal stress on lever-press acquisition with delayed reinforcement in male and female rats. (United States)

    Bruner, Natalie R; Salm, A K; Anderson, Karen G


    The prenatally stressed (PS) rat shows enhanced conditioned fear and increased behavioral inhibition in response to footshock compared to control (CON) rats. It is unclear whether this facilitated learning will occur only with aversive stimulation, or if it will also be observed in the context of positive reinforcement. There are limited and inconsistent data regarding sex differences and the impact of prenatal stress on learning. The present study was designed to examine lever-press acquisition with a 10-s delay to food reinforcement in male and female PS and CON rats. Overall, twice as many PS male rats acquired the lever-press response than the PS female rats, CON male rats, and CON female rats. PS male rats also earned significantly more reinforcers and responded on the operative lever at a significantly greater rate than the other three rat groups. These findings suggest that PS rats exhibit altered learning with a task involving positive reinforcement, and this effect of PS is sex specific for male rats.

  4. Effects of psychotropic agents on extinction of lever-press avoidance in a rat model of anxiety vulnerability

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    Xilu eJiao


    Full Text Available Avoidance and its perseveration represent key features of anxiety disorders. Both pharmacological and behavioral approaches (i.e. anxiolytics and extinction therapy have been utilized to modulate avoidance behavior in patients. However, the outcome has not always been desirable. Part of the reason is attributed to the diverse neuropathology of anxiety disorders. Here, we investigated the effect of psychotropic drugs that target various monoamine systems on extinction of avoidance behavior using lever-press avoidance task. Here we used the Wistar-Kyoto (WKY rat, a unique rat model that exhibits facilitated avoidance and extinction resistance along with malfunction of the dopamine (DA system. Sprague Dawley (SD and WKY rats were trained to acquire lever-press avoidance. WKY rats acquired avoidance faster and to a higher level compared to SD rats. During pharmacological treatment, bupropion, and desipramine significantly reduced avoidance response selectively in WKY rats. However, after the discontinuation of drug treatment, only those WKY rats that were previously treated with desipramine exhibited lower avoidance response compared to the control group. In contrast, none of the psychotropic drugs facilitated avoidance extinction in SD rats. Instead, desipramine impaired avoidance extinction and increased non-reinforced response in SD rats. Interestingly, paroxetine, a widely used antidepressant and anxiolytic, exhibited the weakest effect in WKY rats and no effects at all in SD rats. Thus, our data suggest that malfunctions in brain catecholamine system could be one of the underlying etiologies of anxiety-like behavior, particularly avoidance perseveration. Pharmacological manipulation targeting DA and norepinephrine is more effective to facilitate extinction learning in this strain. The data from the present study may shed light on new pharmacological approaches to treat patients with anxiety disorders who are not responding to serotonin re

  5. Effects of free-food and continuous reinforcement schedule presentation on lever pressing for food by rats


    Raul Avila; Gonzalez, Juan C.; Patricia Miranda


    Six food-deprived rats were each exposed to a procedure in which lever pressingproduced food in the presence and absence of free food. Although the highestfrequency of lever pressing was observed when each lever press was reinforcedwith food in the absence of any supplementary free food, all six rats continuedto press the lever when free food was available. The rats consumed approximatelythe same amount of food when free food was available, whether or not leverpressing was also reinforced. Wh...

  6. Differential activation of accumbens shell and core dopamine by sucrose reinforcement with nose poking and with lever pressing. (United States)

    Bassareo, V; Cucca, F; Frau, R; Di Chiara, G


    In order to investigate the role of modus operandi in the changes of nucleus accumbens (NAc) dopamine (DA) transmission in sucrose reinforcement, extracellular DA was monitored by microdialysis in the NAc shell and core of rats trained on a fixed-ratio 1 schedule to respond for sucrose pellets by nose poking and lever pressing respectively. After training, rats were tested on three different sessions: sucrose reinforcement, extinction and passive sucrose presentation. In rats responding by nose poking dialysate DA increased in the shell but not in the core under reinforced as well as under extinction sessions. In contrast, in rats responding by lever pressing dialysate DA increased both in the accumbens shell and core under reinforced and extinction sessions. Response non-contingent sucrose presentation increased dialysate DA in the shell and core of rats trained to respond for sucrose by nose poking as well as in those trained by lever pressing. In rats trained to respond for sucrose by nose poking on a FR5 schedule dialysate DA also increased selectively in the NAc shell during reinforced responding and in both the shell and core under passive sucrose presentation. These findings, while provide an explanation for the discrepancies existing in the literature over the responsiveness of shell and core DA in rats responding for food, are consistent with the notion that NAc shell and core DA encode different aspects of reinforcement.

  7. [Effects of variable-interval punishment on lever pressing maintained by variable-ratio reinforcement in the rat]. (United States)

    Iida, Naritoshi; Kimura, Hiroshi


    The effects of reinforcement and punishment on response suppression under variable-ratio reinforcement and variable-interval punishment schedules were investigated. In the baseline period, lever pressing in rats was maintained by a variable-ratio food reinforcement schedule. In the punishment condition, responding was punished by a grid shock under a variable-interval schedule. Baseline and punishment conditions alternated, and were continued until the response stabilized. Three rats were given five or six punishment rates with a fixed reinforcement rate and another three rats were given four or five reinforcement rates with a fixed punishment rate. The results indicated that the responses were either completely suppressed or not suppressed at all. When the punishment rate increased or the reinforcement rate decreased, the response was suppressed completely. Whereas when the punishment rate decreased or the reinforcement rate increased, the responses were not suppressed. These results agree with the predictions of the molar theory.

  8. Detailed analysis of food-reinforced operant lever pressing distinguishes effects of a cannabinoid CB1 inverse agonist and dopamine D1 and D2 antagonists. (United States)

    McLaughlin, P J; Winston, K M; Swezey, L A; Vemuri, V K; Makriyannis, A; Salamone, J D


    Overt similarities exist between the effects of systemic cannabinoid CB1 inverse agonists and dopamine (DA) antagonists on appetitive behavior. The present set of studies was undertaken to apply a fine-grained analysis of food-reinforced operant lever pressing in rats in order to compare the pattern of effects produced by administration of the CB1 inverse agonist AM 251 and those induced by the DA D1 antagonist SKF 83566, and the D2 antagonist raclopride. Three groups of rats were trained on a fixed-ratio 5 (FR5) schedule and administered these compounds over a range of doses expected to suppress responding. All three drugs produced a dose-related suppression of total lever pressing. In addition to main effects of dose, regression analyses were performed to determine which of several response timing- and rate-related variables correlated most strongly with overall responding in each group. It was found that total session time spent pausing from responding was significantly better at predicting responding in the AM 251 group, while both DA antagonists produced significantly stronger regression coefficients (versus AM 251) from fast responding measures. These results suggest that, while several similarities exist, CB1, D1, and D2 antagonists are not identical in their pattern of suppression of food-maintained lever pressing.

  9. A novel variable delay Go/No-Go task to study attention, motivation and working memory in the head-fixed rodent [v2; ref status: indexed,

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    Samuel D Dolzani


    Full Text Available In order to parse the causal elements underlying complex behaviors and decision-making processes, appropriate behavioral methods must be developed and used in concurrence with molecular, pharmacological, and electrophysiological approaches. Presented is a protocol for a novel Go/No-Go behavioral paradigm to study the brain attention and motivation/reward circuitry in awake, head-restrained rodents. This experimental setup allows: (1 Pharmacological and viral manipulation of various brain regions via targeted guide cannula; (2 Optogenetic cell-type specific activation and silencing with simultaneous electrophysiological recording and; (3 Repeated electrophysiological single and multiple unit recordings during ongoing behavior. The task consists of three components. The subject first makes an observing response by initiating a trial by lever pressing in response to distinctive Go or No-Go tones.  Then, after a variable delay period, the subject is presented with a challenge period cued by white noise during which they must respond with a lever press for the Go condition or withhold from lever pressing for the duration of the cue in the No-Go condition. After correctly responding during the challenge period (Challenge and a brief delay, a final reward tone of the same frequency as the initiation tone is presented and sucrose reward delivery is available and contingent upon lever pressing. Here, we provide a novel procedure and validating data set that allows researchers to study and manipulate components of behavior such as attention, motivation, impulsivity, and reward-related working memory during an ongoing operant behavioral task while limiting interference from non task-related behaviors.

  10. Is Performance in Task-Cuing Experiments Mediated by Task Set Selection or Associative Compound Retrieval? (United States)

    Forrest, Charlotte L. D.; Monsell, Stephen; McLaren, Ian P. L.


    Task-cuing experiments are usually intended to explore control of task set. But when small stimulus sets are used, they plausibly afford learning of the response associated with a combination of cue and stimulus, without reference to tasks. In 3 experiments we presented the typical trials of a task-cuing experiment: a cue (colored shape) followed,…

  11. Is performance in task-cuing experiments mediated by task set selection or associative compound retrieval? (United States)

    Forrest, Charlotte L D; Monsell, Stephen; McLaren, Ian P L


    Task-cuing experiments are usually intended to explore control of task set. But when small stimulus sets are used, they plausibly afford learning of the response associated with a combination of cue and stimulus, without reference to tasks. In 3 experiments we presented the typical trials of a task-cuing experiment: a cue (colored shape) followed, after a short or long interval, by a digit to which 1 of 2 responses was required. In a tasks condition, participants were (as usual) directed to interpret the cue as an instruction to perform either an odd/even or a high/low classification task. In a cue + stimulus → response (CSR) condition, to induce learning of mappings between cue-stimulus compound and response, participants were, in Experiment 1, given standard task instructions and additionally encouraged to learn the CSR mappings; in Experiment 2, informed of all the CSR mappings and asked to learn them, without standard task instructions; in Experiment 3, required to learn the mappings by trial and error. The effects of a task switch, response congruence, preparation, and transfer to a new set of stimuli differed substantially between the conditions in ways indicative of classification according to task rules in the tasks condition, and retrieval of responses specific to stimulus-cue combinations in the CSR conditions. Qualitative features of the latter could be captured by an associative learning network. Hence associatively based compound retrieval can serve as the basis for performance with a small stimulus set. But when organization by tasks is apparent, control via task set selection is the natural and efficient strategy.

  12. Differences in performance between Sprague-Dawley and Fischer 344 rats in positive reinforcement tasks. (United States)

    Rodriguez, Jesse S; Boctor, Sherin Y; Phelix, Clyde F; Martinez, Joe L


    This experimental investigation tested two different strains of rat, Sprague-Dawley (SD) and Fischer 344 (F344), in their ability to learn lever pressing for food (autoshaping) or intracranial self-administration (ICSA) of dextroamphetamine (AMPH) into the nucleus accumbens (NAcc). Additionally, a unique method of intracranial drug delivery was utilized, via reverse dialysis, by the use of a microdiaylsis probe. The experiments revealed definite behavioral differences between SD and F344 animals. The autoshaping data indicated that SD rats, on average, acquired lever pressing for food in fewer training days than F344 rats. Also, the ICSA experiment revealed that SD rats self-administered AMPH at a 30 mug/mul concentration. Lever pressing was significantly greater in those SD rats receiving AMPH than in the F344 drug group. Furthermore, the F344 rats never acquired lever pressing for intra-NAcc delivery of AMPH under our testing regime. These data reveal differences in performance of positively reinforced operant tasks between the inbred F344 rats as compared to the outbred SD strain.

  13. Dopaminergic modulation of effort-related choice behavior as assessed by a progressive ratio chow feeding choice task: pharmacological studies and the role of individual differences.

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    Patrick A Randall

    Full Text Available Mesolimbic dopamine (DA is involved in behavioral activation and effort-related processes. Rats with impaired DA transmission reallocate their instrumental behavior away from food-reinforced tasks with high response requirements, and instead select less effortful food-seeking behaviors. In the present study, the effects of several drug treatments were assessed using a progressive ratio (PROG/chow feeding concurrent choice task. With this task, rats can lever press on a PROG schedule reinforced by a preferred high-carbohydrate food pellet, or alternatively approach and consume the less-preferred but concurrently available laboratory chow. Rats pass through each ratio level 15 times, after which the ratio requirement is incremented by one additional response. The DA D(2 antagonist haloperidol (0.025-0.1 mg/kg reduced number of lever presses and highest ratio achieved but did not reduce chow intake. In contrast, the adenosine A(2A antagonist MSX-3 increased lever presses and highest ratio achieved, but decreased chow consumption. The cannabinoid CB1 inverse agonist and putative appetite suppressant AM251 decreased lever presses, highest ratio achieved, and chow intake; this effect was similar to that produced by pre-feeding. Furthermore, DA-related signal transduction activity (pDARPP-32(Thr34 expression was greater in nucleus accumbens core of high responders (rats with high lever pressing output compared to low responders. Thus, the effects of DA antagonism differed greatly from those produced by pre-feeding or reduced CB1 transmission, and it appears unlikely that haloperidol reduces PROG responding because of a general reduction in primary food motivation or the unconditioned reinforcing properties of food. Furthermore, accumbens core signal transduction activity is related to individual differences in work output.

  14. Effects of caffeine on anticipatory control processes : Evidence from a cued task-switch paradigm

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    Tieges, Zoe; Snel, Jan; Kok, Albert; Plat, Niels; Ridderinkhof, Richard


    Effects of caffeine on task switching were studied using ERPs in a cued task-switch paradigm. The need for advance preparation was manipulated by varying the number of task-set aspects that required switching. In a double-blind, within-subjects experiment, caffeine reduced shift costs compared to pl

  15. Prefrontal cortex lesions and scopolamine impair attention performance of C57BL/6 mice in a novel 2-choice visual discrimination task. (United States)

    Dillon, Gregory M; Shelton, Delia; McKinney, A P; Caniga, Michael; Marcus, Jacob N; Ferguson, Mitchell T; Kornecook, Thomas J; Dodart, Jean-Cosme


    Sustained attention is defined as the ability or capacity to remain focused on the occurrence of rare events over long periods of time. We describe here the development of a novel, operant-based attention task that can be learned by mice in 8-10 days. Mice were trained on a 2-choice visual discrimination task in an operant chamber, wherein the correct response on any given trial was a lever-press cued by a stimulus light. Upon reaching a criterion of greater than 80% correct responses, all subjects were tested in a mixed-trial attention paradigm combining four different stimulus durations within a single session (0.5, 1, 2, or 10 s). During attention testing, the percentage of correct responses decreased as a function of stimulus duration, indicating a performance decrement which parallels increasing attentional demand within the task. Pretreatment with the muscarinic-receptor antagonist scopolamine yielded a reliable, dose-dependent performance deficit whereas nicotine treatment improved the percentage of correct responses during trials with the greatest attentional demand. Moreover, medial prefrontal cortex lesions impaired attention performance without affecting acquisition or retention of the discrimination rule. These results underscore the utility of this task as a novel means of assessing attentional processes in mice in a relatively high-throughput manner.

  16. Exposing the cuing task: the case of gaze and arrow cues. (United States)

    Hayward, Dana A; Ristic, Jelena


    The prevailing theoretical accounts of social cognitive processes propose that attention is preferentially engaged by social information. However, empirical investigations report virtually indistinguishable attention effects for social (e.g., gaze) and nonsocial (e.g., arrow) stimuli when a cuing task is used. Here, we show that this discrepancy between theory and data reflects a difference in how the extraneous processes induced by the cuing task's parameters (i.e., tonic alertness and voluntary temporal preparation) modulate cue-specific attentional effects. Overall, we found that tonic alertness and voluntary temporal preparation interacted within the cuing task, resulting in underadditive magnitudes of spatial orienting and superadditive magnitudes of the foreperiod effect. However, those interactions differentially affected social and nonsocial attention. While typical rapid social orienting was resilient to changing task parameters, sustained social orienting was eliminated only when the contribution of both extraneous processes was reduced. In contrast, orienting elicited by nonsocial arrows grew in magnitude with the reduction of voluntary temporal preparation and was delayed by the joint reduction of tonic alertness and voluntary temporal preparation. Together, these data indicate that cue-specific attention effects are masked by task dynamics of the cuing paradigm and highlight a pivotal role of the cuing task parameters in both the measurement and the theoretical attribution of spatial attention effects.

  17. Quantitative Analysis of Language Production in Parkinson's Disease Using a Cued Sentence Generation Task (United States)

    Vanhoutte, Sarah; De Letter, Miet; Corthals, Paul; Van Borsel, John; Santens, Patrick


    The present study examined language production skills in Parkinson's disease (PD) patients. A unique cued sentence generation task was created in order to reduce demands on memory and attention. Differences in sentence production abilities according to disease severity and cognitive impairments were assessed. Language samples were obtained from 20…

  18. Effects of aging and dual tasking on step adjustments to perturbations in visually cued walking. (United States)

    Mazaheri, Masood; Hoogkamer, Wouter; Potocanac, Zrinka; Verschueren, Sabine; Roerdink, Melvyn; Beek, Peter J; Peper, C E; Duysens, Jacques


    Making step adjustments is an essential component of walking. However, the ability to make step adjustments may be compromised when the walker's attentional capacity is limited. This study compared the effects of aging and dual tasking on step adjustments in response to stepping-target perturbations during visually cued treadmill walking. Fifteen older adults (69.4 ± 5.0 years; mean ± SD) and fifteen young adults (25.4 ± 3.0 years) walked at a speed of 3 km/h on a treadmill. Both groups performed visually cued step adjustments in response to unpredictable shifts of projected stepping targets in forward (FW), backward (BW) or sideward (SW) directions, at different levels of task difficulty [which increased as the available response distance (ARD) decreased], and with and without dual tasking (auditory Stroop task). In both groups, step adjustments were smaller than required. For FW and BW shifts, older adults undershot more under dual-task conditions. For these shifts, ARD affected the age groups differentially. For SW shifts, larger errors were found for older adults, dual tasking and the most difficult ARD. Stroop task performance did not differ between groups in all conditions. Older adults have more difficulty than young adults to make corrective step adjustments while walking, especially under dual-tasking conditions. Furthermore, they seemed to prioritize the cognitive task over the step adjustment task, a strategy that may pose aging populations at a greater fall risk. For comparable task difficulty, the older adults performed considerably worse than the young adults, indicating a decreased ability to adjust steps under time pressure.

  19. Genetic influences on free and cued recall in long-term memory tasks. (United States)

    Volk, Heather E; McDermott, Kathleen B; Roediger, Henry L; Todd, Richard D


    Long-term memory (LTM) problems are associated with many psychiatric and neurological illnesses and are commonly measured using free and cued recall tasks. Although LTM has been linked with biologic mechanisms, the etiology of distinct LTM tasks is unknown. We studied LTM in 95 healthy female twin pairs identified through birth records in the state of Missouri. Performance on tasks of free recall of unrelated words, free and cued recall of categorized words, and the vocabulary section of the Wechsler Adult Intelligence Scale (WAIS-R) were examined using structural equation modeling. Additive genetic and unique environmental factors influenced LTM and intelligence. Free recall of unrelated and categorized words, and cued recall of categorized words, were moderately heritable (55%, 38%, and 37%). WAIS-R vocabulary score was highly heritable (77%). Controlling for verbal intelligence in multivariate analyses of recall, two components of genetic influence on LTM were found; one for all three recall scores and one for free and cued categorized word recall. Recall of unrelated and categorized words is influenced by different genetic and environmental factors indicating heterogeneity in LTM. Verbal intelligence is etiologically different from LTM indicating that these two abilities utilize different brain functions.

  20. Investigating a method for reducing residual switch costs in cued task switching. (United States)

    Schneider, Darryl W


    Residual switch costs in cued task switching are performance decrements that occur despite a long cue-target interval (CTI) to prepare for a task switch. Verbruggen, Liefooghe, Vandierendonck, and Demanet (Journal of Experimental Psychology: Learning, Memory, and Cognition, 33; 342-356, 2007) showed that briefly presenting the cue during the CTI and leaving it absent after target onset yielded smaller residual switch costs than those obtained when the cue was available for the full CTI and remained present after target onset. The potential effects of cue availability during the CTI (full or partial) and cue status after target onset (present or absent) on residual switch costs were investigated in the present study. In Experiments 1 and 2, cue status was manipulated while holding cue availability constant. In Experiments 3 and 4, cue status and cue availability were manipulated factorially. Residual switch costs were obtained, but they were not modulated consistently by cue status or cue availability across experiments. In Experiment 5, a direct replication of one of Verbruggen and colleagues' experiments yielded divergent results. Implications for understanding task switching are discussed.

  1. Anticipatory processes in brain state switching - evidence from a novel cued-switching task implicating default mode and salience networks. (United States)

    Sidlauskaite, Justina; Wiersema, Jan R; Roeyers, Herbert; Krebs, Ruth M; Vassena, Eliana; Fias, Wim; Brass, Marcel; Achten, Eric; Sonuga-Barke, Edmund


    The default mode network (DMN) is the core brain system supporting internally oriented cognition. The ability to attenuate the DMN when switching to externally oriented processing is a prerequisite for effective performance and adaptive self-regulation. Right anterior insula (rAI), a core hub of the salience network (SN), has been proposed to control the switching from DMN to task-relevant brain networks. Little is currently known about the extent of anticipatory processes subserved by DMN and SN during switching. We investigated anticipatory DMN and SN modulation using a novel cued-switching task of between-state (rest-to-task/task-to-rest) and within-state (task-to-task) transitions. Twenty healthy adults performed the task implemented in an event-related functional magnetic resonance imaging (fMRI) design. Increases in activity were observed in the DMN regions in response to cues signalling upcoming rest. DMN attenuation was observed for rest-to-task switch cues. Obversely, DMN was up-regulated by task-to-rest cues. The strongest rAI response was observed to rest-to-task switch cues. Task-to-task switch cues elicited smaller rAI activation, whereas no significant rAI activation occurred for task-to-rest switches. Our data provide the first evidence that DMN modulation occurs rapidly and can be elicited by short duration cues signalling rest- and task-related state switches. The role of rAI appears to be limited to certain switch types - those implicating transition from a resting state and to tasks involving active cognitive engagement.

  2. The VMAT-2 inhibitor tetrabenazine affects effort-related decision making in a progressive ratio/chow feeding choice task: reversal with antidepressant drugs.

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    Patrick A Randall

    Full Text Available Behavioral activation is a fundamental feature of motivation, and organisms frequently make effort-related decisions based upon evaluations of reinforcement value and response costs. Furthermore, people with major depression and other disorders often show anergia, psychomotor retardation, fatigue, and alterations in effort-related decision making. Tasks measuring effort-based decision making can be used as animal models of the motivational symptoms of depression, and the present studies characterized the effort-related effects of the vesicular monoamine transport (VMAT-2 inhibitor tetrabenazine. Tetrabenazine induces depressive symptoms in humans, and also preferentially depletes dopamine (DA. Rats were assessed using a concurrent progressive ratio (PROG/chow feeding task, in which they can either lever press on a PROG schedule for preferred high-carbohydrate food, or approach and consume a less-preferred lab chow that is freely available in the chamber. Previous work has shown that the DA antagonist haloperidol reduced PROG work output on this task, but did not reduce chow intake, effects that differed substantially from those of reinforcer devaluation or appetite suppressant drugs. The present work demonstrated that tetrabenazine produced an effort-related shift in responding on the PROG/chow procedure, reducing lever presses, highest ratio achieved and time spent responding, but not reducing chow intake. Similar effects were produced by administration of the subtype selective DA antagonists ecopipam (D1 and eticlopride (D2, but not by the cannabinoid CB1 receptor neutral antagonist and putative appetite suppressant AM 4413, which suppressed both lever pressing and chow intake. The adenosine A2A antagonist MSX-3, the antidepressant and catecholamine uptake inhibitor bupropion, and the MAO-B inhibitor deprenyl, all reversed the impairments induced by tetrabenazine. This work demonstrates the potential utility of the PROG/chow procedure as a

  3. Differential effects of emotionally versus neutrally cued autobiographical memories on performance of a subsequent cognitive task: Effects of task difficulty

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    Kymberly eYoung


    Full Text Available Attention is a limited resource, and in order to improve processing of the attended information, competing processes must be suppressed. Although it is well established that an experimentally induced change in mood state comprises one type of competing process that can impair performance on a subsequent task, no study has investigated whether an emotionally valenced autobiographical memory (AM also can alter performance on a subsequent task. We therefore examined the effects of AM recall on cognitive performance. Healthy participants (n=20 per experiment recalled AMs in response to positive, negative, and neutral cue words. Following each AM participants completed a simple perceptual task (Experiment 1 or solved moderately difficult subtraction problems (Experiment 2. In Experiment 1 participants performed less accurately following exposure to positive or negative versus neutral cue words (ps<0.001, and also were less accurate following negative versus positive cue words (p<0.001. In Experiment 2, in contrast, no difference in accuracy or response times reached statistical significance. Performance accuracy even trended towards being higher following exposure to negative versus neutral cue words (p=0.08. The results of Experiment 1 suggested that recalling emotionally salient AMs reduces the attention directed toward a simple continuous performance task administered immediately following the AM task, conceivably due to persistent contemplation of the AM. The negative results of Experiment 2 suggested that the effect of AMs on attention was attenuated, however, by increasing the difficulty of the subsequent task. Our results have implications for patients with MDD, as performing cognitively demanding tasks may allow them to attenuate the impairing effects of negative rumination on cognition.

  4. Functional Roles of Neural Preparatory Processes in a Cued Stroop Task Revealed by Linking Electrophysiology with Behavioral Performance.

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    Chao Wang

    Full Text Available It is well established that cuing facilitates behavioral performance and that different aspects of instructional cues evoke specific neural preparatory processes in cued task-switching paradigms. To deduce the functional role of these neural preparatory processes the majority of studies vary aspects of the experimental paradigm and describe how these variations alter markers of neural preparatory processes. Although these studies provide important insights, they also have notable limitations, particularly in terms of understanding the causal or functional relationship of neural markers to cognitive and behavioral processes. In this study, we sought to address these limitations and uncover the functional roles of neural processes by examining how variability in the amplitude of neural preparatory processes predicts behavioral performance to subsequent stimuli. To achieve this objective 16 young adults were recruited to perform a cued Stroop task while their brain activity was measured using high-density electroencephalography. Four temporally overlapping but functionally and topographically distinct cue-triggered event related potentials (ERPs were identified: 1 A left-frontotemporal negativity (250-700 ms that was positively associated with word-reading performance; 2 a midline-frontal negativity (450-800 ms that was positively associated with color-naming and incongruent performance; 3 a left-frontal negativity (450-800 ms that was positively associated with switch trial performance; and 4 a centroparietal positivity (450-800 ms that was positively associated with performance for almost all trial types. These results suggest that at least four dissociable cognitive processes are evoked by instructional cues in the present task, including: 1 domain-specific task facilitation; 2 switch-specific task-set reconfiguration; 3 preparation for response conflict; and 4 proactive attentional control. Examining the relationship between ERPs and behavioral

  5. The effects of priming in a cued dot-probe task on appearance-related attentional biases in women. (United States)

    Lane, Ben R; Mulgrew, Kate E; Mahar, Doug; White, Melanie J; Loughnan, Siobhan A


    The dot-probe task (DPT) is a reaction time measure of attentional bias. Research using this task has found inconsistent patterns of appearance-related attentional biases in women. This study examined the effects of a novel priming variation of the DPT, which incorporated additional cues into each trial of the task, on measurement of such biases. The study also examined associations between these biases and body image, a component of eating disorder symptomatology. A convenience sample of women from the general community (N = 103) completed body image measures online and attended a laboratory session to complete one of four DPTs: (1) an appearance-cued DPT containing images of thin-ideal models between each trial; (2) neutral-cued DPT containing images of forests; (3) time-delayed DPT controlling for time in place of an image; or (4) typical DPT containing only word stimuli. Women who completed the appearance-cued DPT demonstrated a stronger attentional bias for positive, but not negative, appearance words than women who completed the other DPT versions. Furthermore, for the appearance-cued and time-delayed DPTs, this bias correlated with poorer body image across several indicators (appearance evaluation, body dissatisfaction, self-evaluative salience of appearance, and state body satisfaction). Although it was unexpected that no attentional bias for negative-appearance words was found, the attentional bias for positive-appearance words may suggest that effects were driven by the ego-threat of positive-appearance words. Further research is warranted to determine whether such biases contribute to and maintain body image disturbance and disordered eating. © 2017 Wiley Periodicals, Inc.

  6. Inefficient cognitive control in adult ADHD: evidence from trial-by-trial Stroop test and cued task switching performance

    Directory of Open Access Journals (Sweden)

    Heuser Isabella


    Full Text Available Abstract Background Contemporary neuropsychological models of ADHD implicate impaired cognitive control as contributing to disorder characteristic behavioral deficiencies and excesses; albeit to varying degrees. While the traditional view of ADHD postulates a core deficiency in cognitive control processes, alternative dual-process models emphasize the dynamic interplay of bottom-up driven factors such as activation, arousal, alerting, motivation, reward and temporal processing with top-down cognitive control. However, neuropsychological models of ADHD are child-based and have yet to undergo extensive empirical scrutiny with respect to their application to individuals with persistent symptoms in adulthood. Furthermore, few studies of adult ADHD samples have investigated two central cognitive control processes: interference control and task-set coordination. The current study employed experimental chronometric Stroop and task switching paradigms to investigate the efficiency of processes involved in interference control and task-set coordination in ADHD adults. Methods 22 adults diagnosed with persistent ADHD (17 males and 22 matched healthy control subjects performed a manual trial-by-trial Stroop color-word test and a blocked explicitly cued task switching paradigm. Performance differences between neutral and incongruent trials of the Stroop task measured interference control. Task switching paradigm manipulations allowed for measurement of transient task-set updating, sustained task-set maintenance, preparatory mechanisms and interference control. Control analyses tested for the specificity of group × condition interactions. Results Abnormal processing of task-irrelevant stimulus features was evident in ADHD group performance on both tasks. ADHD group interference effects on the task switching paradigm were found to be dependent on the time allotted to prepare for an upcoming task. Group differences in sustained task-set maintenance and

  7. Long-lasting effects of performance-contingent unconscious and conscious reward incentives during cued task-switching. (United States)

    Capa, Rémi L; Bouquet, Cédric A; Dreher, Jean-Claude; Dufour, André


    Motivation is often thought to interact consciously with executive control, although recent studies have indicated that motivation can also be unconscious. To date, however, the effects of unconscious motivation on high-order executive control functions have not been explored. Only a few studies using subliminal stimuli (i.e., those not related to motivation, such as an arrow to prime a response) have reported short-lived effects on high-order executive control functions. Here, building on research on unconscious motivation, in which a behavior of perseverance is induced to attain a goal, we hypothesized that subliminal motivation can have long-lasting effects on executive control processes. We investigated the impact of unconscious/conscious monetary reward incentives on evoked potentials and neural activity dynamics during cued task-switching performance. Participants performed long runs of task-switching. At the beginning of each run, a reward (50 cents or 1 cent) was displayed, either subliminally or supraliminally. Participants earned the reward contingent upon their correct responses to each trial of the run. A higher percentage of runs was achieved with higher (conscious and unconscious) than lower rewards, indicating that unconscious high rewards have long-lasting behavioral effects. Event-related potential (ERP) results indicated that unconscious and conscious rewards influenced preparatory effort in task preparation, as suggested by a greater fronto-central contingent negative variation (CNV) starting at cue-onset. However, a greater parietal P3 associated with better reaction times (RTs) was observed only under conditions of conscious high reward, suggesting a larger amount of working memory invested during task performance. Together, these results indicate that unconscious and conscious motivations are similar at early stages of task-switching preparation but differ during task performance. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Adult age differences in learning on a sequentially cued prediction task. (United States)

    Seaman, Kendra L; Howard, Darlene V; Howard, James H


    Much of adaptive behavior relies on the ability to learn and generate predictions about relationships in the environment. Research on aging suggests both that there is an age deficit in the ability to learn sequential relationships and that this deficit in learning could underlie age differences reported in many decision-making tasks. This article introduces the Triplets Prediction Task (TPT) to investigate the learning of sequential relationships that underlies adaptive behavior. In the TPT, participants see 2 successive visual cues and then predict which target will follow. Unknown to participants, there is a predictive relationship between the first cue and the target such that each of 4 cues predicts 1 of 4 targets 85% of the time. Although both age groups demonstrated learning on this task, an age deficit in learning appeared early and performance differences persisted throughout training. There was also evidence of age differences in the learning systems engaged during the task. These results are consistent with previous studies of learning and prediction, and they support the growing literature showing adult age differences in decision making from experience. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail:

  9. Hand Movement Deviations in a Visual Search Task with Cross Modal Cuing (United States)

    Aslan, Asli; Aslan, Hurol


    The purpose of this study is to demonstrate the cross-modal effects of an auditory organization on a visual search task and to investigate the influence of the level of detail in instructions describing or hinting at the associations between auditory stimuli and the possible locations of a visual target. In addition to measuring the participants'…

  10. Structure of Enhanced Cued Recall Task in the 7 Minute Screen Test. (United States)

    Mora-Simon, Sara; Ladera-Fernandez, Valentina; Garcia-Garcia, Ricardo; Patino-Alonso, María C; Perea-Bartolome, M Victoria; Unzueta-Arce, Jaime; Perez-Arechaederra, Diana; Rodriguez-Sanchez, Emiliano


    Episodic memory in the 7 Minute Screen is assessed by the Enhanced Cued Recall (ECR) test. The ECR test is composed of three phases, Identification, Immediate Recall, and Free and Cued Recall. However, just the last phase is considered for the total score. We believe that collecting the performance data of the Identification and Immediate Recall phases could provide information regarding possible difficulties or impairments in the different aspects involved in the temporal mnesic process of acquisition of new information, such as in working memory or visual identification. The objective was to assess the goodness of fit for the three phases of the ECR test using a Confirmatory Factor Analysis (CFA) to show if each phase is separated from each other as a different aspect that participates in the mnesic process. A total of 311 participants greater than 65 years were included in this study. Confirmatory factor analyses were conducted for each individual phase. The analyses show that the ECR test consists of three separate phases that identify different steps of the mnesic process. Individual scores for each phase could allow for investigation of patient performance in different aspects of the memory process and could help in further neuropsychological assessment.

  11. Hand movement deviations in a visual search task with cross modal cuing

    Directory of Open Access Journals (Sweden)

    Hürol Aslan


    Full Text Available The purpose of this study is to demonstrate the cross-modal effects of an auditory organization on a visual search task and to investigate the influence of the level of detail in instructions describing or hinting at the associations between auditory stimuli and the possible locations of a visual target. In addition to measuring the participants’ reaction times, we paid special attention to tracking the hand movements toward the target. According to the results, the auditory stimuli unassociated with the target locations slightly –but significantly- increased the deviation of the hand movement from the path leading to the target location. The increase in the deviation depended on the degree of association between auditory stimuli and target locations, albeit not on the level of detail in the instructions about the task.

  12. Hand movement deviations in a visual search task with cross modal cuing


    Hürol Aslan; Asli Aslan


    The purpose of this study is to demonstrate the cross-modal effects of an auditory organization on a visual search task and to investigate the influence of the level of detail in instructions describing or hinting at the associations between auditory stimuli and the possible locations of a visual target. In addition to measuring the participants reaction times, we paid special attention to tracking the hand movements toward the target. According to the results, t...

  13. Dispatching the wandering mind? Toward a laboratory method for cuing "spontaneous" off-task thought

    Directory of Open Access Journals (Sweden)

    Jennifer C. McVay


    Full Text Available Cognitive psychologists and neuroscientists study most phenomena of attention by measuring subjects’ overt responses to discrete environmental stimuli that can be manipulated to test competing theories. The mind-wandering experience, however, cannot be locally instigated by cleverly engineered stimuli. Investigators must therefore rely on correlational and observational methods to understand subjects’ flow of thought, which is only occasionally and indirectly monitored. In an effort toward changing this state of affairs, we present four experiments that develop a method for inducing mind-wandering episodes – on demand – in response to task-embedded cues. In an initial laboratory session, subjects described their personal goals and concerns across several life domains (amid some filler questionnaires. In a second session, 48 hours later, subjects completed a go/no-go task in which they responded to the perceptual features of words; unbeknownst to subjects, some stimulus words were presented in triplets to represent the personal concerns they had described in session 1. Thought probes appearing shortly after these personal-goal triplets indicated that, compared to control triplets, priming subjects’ concerns increased mind-wandering rate by about 3 – 4%. We argue that this small effect is, nonetheless, a promising development toward the pursuit of an experimentally informed, theory-driven science of mind wandering.

  14. Dispatching the wandering mind? Toward a laboratory method for cuing "spontaneous" off-task thought. (United States)

    McVay, Jennifer C; Kane, Michael J


    Cognitive psychologists and neuroscientists study most phenomena of attention by measuring subjects' overt responses to discrete environmental stimuli that can be manipulated to test competing theories. The mind wandering experience, however, cannot be locally instigated by cleverly engineered stimuli. Investigators must therefore rely on correlational and observational methods to understand subjects' flow of thought, which is only occasionally and indirectly monitored. In an effort toward changing this state of affairs, we present four experiments that develop a method for inducing mind wandering episodes-on demand-in response to task-embedded cues. In an initial laboratory session, subjects described their personal goals and concerns across several life domains (amid some filler questionnaires). In a second session, 48 h later, subjects completed a go/no-go task in which they responded to the perceptual features of words; unbeknownst to subjects, some stimulus words were presented in triplets to represent the personal concerns they had described in session 1. Thought probes appearing shortly after these personal-goal triplets indicated that, compared to control triplets, priming subjects' concerns increased mind wandering rate by about 3-4%. We argue that this small effect is, nonetheless, a promising development toward the pursuit of an experimentally informed, theory-driven science of mind wandering.

  15. Learning strategy preference of 5XFAD transgenic mice depends on the sequence of place/spatial and cued training in the water maze task. (United States)

    Cho, Woo-Hyun; Park, Jung-Cheol; Chung, ChiHye; Jeon, Won Kyung; Han, Jung-Soo


    Learning strategy preference was assessed in 5XFAD mice, which carry 5 familial Alzheimer's disease (AD) mutations. Mice were sequentially trained in cued and place/spatial versions of the water maze task. After training, a strategy preference test was conducted in which mice were required to choose between the spatial location where the platform had previously been during the place/spatial training, and a visible platform in a new location. 5XFAD and non-transgenic control mice showed equivalent escape performance in both training tasks. However, in the strategy preference test, 5XFAD mice preferred a cued strategy relative to control mice. When the training sequence was presented in the reverse order (i.e., place/spatial training before cued training), 5XFAD mice showed impairments in place/spatial training, but no differences in cued training or in the strategy preference test comparing to control. Analysis of regional Aβ42 deposition in brains of 5XFAD mice showed that the hippocampus, which is involved in the place/spatial learning strategy, had the highest levels of Aβ42 and the dorsal striatum, which is involved in cued learning strategy, showed a small increase in Aβ42 levels. The effect of training protocol order on performance, and regional differences in Aβ42 deposition observed in 5XFAD mice, suggest differential functional recruitment of brain structures related to learning in healthy and AD individuals.

  16. Behavioral, Cognitive, and Motor Preparation Deficits in a Visual Cued Spatial Attention Task in Autism Spectrum Disorder. (United States)

    Sokhadze, Estate M; Tasman, Allan; Sokhadze, Guela E; El-Baz, Ayman S; Casanova, Manuel F


    Abnormalities in motor skills have been regarded as part of the symptomatology characterizing autism spectrum disorder (ASD). It has been estimated that 80 % of subjects with autism display "motor dyspraxia" or clumsiness that are not readily identified in a routine neurological examination. In this study we used behavioral measures, event-related potentials (ERP), and lateralized readiness potential (LRP) to study cognitive and motor preparation deficits contributing to the dyspraxia of autism. A modified Posner cueing task was used to analyze motor preparation abnormalities in children with autism and in typically developing children (N = 30/per group). In this task, subjects engage in preparing motor response based on a visual cue, and then execute a motor movement based on the subsequent imperative stimulus. The experimental conditions, such as the validity of the cue and the spatial location of the target stimuli were manipulated to influence motor response selection, preparation, and execution. Reaction time and accuracy benefited from validly cued targets in both groups, while main effects of target spatial position were more obvious in the autism group. The main ERP findings were prolonged and more negative early frontal potentials in the ASD in incongruent trials in both types of spatial location. The LRP amplitude was larger in incongruent trials and had stronger effect in the children with ASD. These effects were better expressed at the earlier stages of LRP, specifically those related to response selection, and showed difficulties at the cognitive phase of stimulus processing rather that at the motor execution stage. The LRP measures at different stages reflect the chronology of cognitive aspects of movement preparation and are sensitive to manipulations of cue correctness, thus representing very useful biomarker in autism dyspraxia research. Future studies may use more advance and diverse manipulations of movement preparation demands in testing more

  17. A visual, position-independent instrumental reinforcer devaluation task for rats. (United States)

    West, Elizabeth A; Forcelli, Patrick A; Murnen, Alice; Gale, Karen; Malkova, Ludise


    Flexible goal-directed behavior has been studied across species using reinforcer devaluation tasks, in which subjects form associations between specific stimuli (cues) and specific reinforcer(s). The reinforcer is subsequently devalued by selective satiation or taste aversion. Following devaluation, subjects adjust their responding to the cues reflecting the new value of the reinforcer. Tasks currently used in rats differ in several ways from tasks used in monkeys and this may explain contrasting results between the two species. To address one of the differences, we developed a rat task independent of spatial cues. It employs two visual cues presented simultaneously, changing left and right positions pseudorandomly. Each cue predicts one of two food reinforcers. Rats were trained to lever press in response to the two visual cues. Subsequently, they were satiated on one of the foods followed by an extinction test where in each trial they could choose to respond to one of the two cues, one predicting the devalued reinforcer and the other the non-devalued. This procedure was repeated later with the alternative food devalued. The rats adjusted their responding by choosing the cue predicting the devalued food significantly less (pdevalue two different foods by selective satiation, and transfer the new value to the visual cues. Discrimination of the visual cues is not aided by spatial cues, thereby eliminating a major difference between the instrumental tasks used in rats and the task used in monkeys.

  18. The Ease-of-task and Part-list Cuing Effect%任务难度与部分线索效应

    Institute of Scientific and Technical Information of China (English)

    唐卫海; 谢思源; 刘湍丽; 刘希平


    -list cuing effect exists in Chinese vocabulary memory task whatever the study words are difficult or not and no matter whether the orders of presenting the study words are random or in the way of category ; second, the size of the part-list cuing effect is reduced while the degrees difficulties of study items are getting lower and lower.%部分线索效应是指在学习一个词表后,呈现已学项目中的一部分作为回忆线索去回忆其他项目时,回忆效果反而不如没有线索组的效果好。研究通过三个实验探讨了不同任务难度的部分线索效应。结果表明:①在中文词表记忆中存在部分线索效应;②随着学习材料难度的提高由部分线索造成的提取成绩的削减量降低。这一研究结果支持了部分线索效应的策略破坏假说。

  19. Kinematic strategies underlying improvement in the acquisition of a sequential finger task with self-generated vs. Cued repetition training.

    Directory of Open Access Journals (Sweden)

    Jason Friedman

    Full Text Available Many motor skills, such as typing, consist of articulating simple movements into novel sequences that are executed faster and smoother with practice. Dynamics of re-organization of these movement sequences with multi-session training and its dependence on the amount of self-regulation of pace during training is not yet fully understood. In this study, participants practiced a sequence of key presses. Training sessions consisted of either externally (Cued or self-initiated (Uncued training. Long-term improvements in performance speed were mainly due to reducing gaps between finger movements in both groups, but Uncued training induced higher gains. The underlying kinematic strategies producing these changes and the representation of the trained sequence differed significantly across subjects, although net gains in speed were similar. The differences in long-term memory due to the type of training and the variation in strategies between subjects, suggest that the different neural mechanisms may subserve the improvements observed in overall performance.

  20. Lever attacking and pressing as a function of conditioning and extinguishing a lever-press avoidance response in rats. (United States)

    Pear, J J; Hemingway, M J; Keizer, P


    Six experimental rats were conditioned to press one of two available levers to avoid shock. The levers registered bites as well as presses. For four of these rats, shock was contingent on lever bites when a specified time period had elapsed after the previous shock. An extinction period, in which only periodic noncontingent shocks were presented, followed avoidance training. Six yoked-control rats received the same sequence of shocks as did the corresponding experimental rats in both the conditioning and extinction phases. All six experimental rats repeatedly bit the avoidance lever. Four bit it more than the nonavoidance lever during conditioning, and five bit it more during extinction. Five of the six experimental rats consistently bit the levers many more times during each session than did their respective control rats, suggesting that avoidance conditioning facilitated lever biting. Rates of lever biting and pressing by all of the experimental rats and by some of the control rats were highest immediately following shock throughout both phases. During later portions of the intervals following shock, characteristic effects of conditioning and extinction were observed. This finding suggests that extinction of avoidance behavior by unavoidable shock presentations can be demonstrated more readily when shock-elicited responding is extricated from the data.

  1. Status of ITER task T213 collaborative irradiation screening experiment on Cu/SS joints in the Russian Federation SM-2-reactor

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, D.J. [Pacific Northwest National Lab., Richland, WA (United States); Fabritsiev, S.A. [D.V. Efremov Inst., St. Petersburg (Russian Federation); Pokrovsky, A.S. [SRIAR, Dimitrovgrad (Russian Federation); Zinkle, S.J. [Oak Ridge National Lab., TN (United States)] [and others


    Specimen fabrication is underway for an irradiation screening experiment planned to start in January 1996 in the SM-2 reactor in Dimitrovgrad, Russia. The purpose of the experiment is to evaluate the effects of neutron irradiation at ITER-relevant temperatures on the bond integrity performance of Cu/SS and Be/Cu joints, as well as to further investigate the base metal properties of irradiated copper alloys. Specimens from each of the four ITER parties (U.S., EU, japan, and RF) will be irradiated to a dose of {approx}0.2 dpa at two different temperatures, 150 and 300{degrees}C. The specimens will consist of Cu/SS and Be/Cu joints in several different geometries, as well as a large number of specimens from the base materials. Fracture toughness data on base metal and Cu/SS bonded specimens will be obtained from specimens supplied by the U.S. Due to lack of material, the Be/Cu specimens supplied by the U.S will only be irradiated as TEM disks.

  2. The effects of brief visual interruption tasks on drivers' ability to resume their visual search for a pre-cued hazard. (United States)

    Borowsky, Avinoam; Horrey, William J; Liang, Yulan; Garabet, Angela; Simmons, Lucinda; Fisher, Donald L


    Driver visual distraction is known to increase the likelihood of being involved in a crash, especially for long glances inside the vehicle. The detrimental impact of these in-vehicle glances may carry over and disrupt the ongoing processing of information after the driver glances back up on the road. This study explored the effect of different types of visual tasks inside the vehicle on the top-down processes that guide the detection and monitoring of road hazards after the driver glances back towards the road. Using a driving simulator, 56 participants were monitored with an eye tracking system while they navigated various hazardous scenarios in one of four experimental conditions. In all conditions, a potential hazard was visible 4-5s before the driver could strike the potential hazard were it to materialize. All interruptions were exactly two seconds in length. After the interruption the potential hazard again became visible for about a half-second after which the driver passed by the hazard. The nature of the in-vehicle visual interruption presented to the participants was varied across conditions: (1) Visual interruptions comprised of spatial, driving unrelated, tasks; (2) visual interruptions comprised of non-spatial, driving unrelated, tasks; (3) visual interruptions with no tasks added; and (4) no visual interruptions. In the first three conditions drivers glancing on the forward roadway was momentarily interrupted (either with or without a task) just after the potential hazard first became visible by the occurrence of an in-vehicle task lasting two seconds. In the last condition (no interruptions) the driver could not see the potential hazard after it just became visible because of obstructions in the built or natural environment. The obstruction (like the interruption) lasted for two seconds. In other words, across all conditions the hazard was visible, then became invisible, and finally became visible again. Importantly, the results show that the

  3. Reinforcing effect for corn oil stimulus was concentration dependent in an operant task in mice. (United States)

    Yoneda, Takeshi; Taka, Yuichi; Okamura, Maya; Mizushige, Takafumi; Matsumura, Shigenobu; Manabe, Yasuko; Tsuzuki, Satoshi; Inoue, Kazuo; Fushiki, Tohru


    Corn oil is reported to elicit a conditioned place preference (CPP) in a CPP test in mice. To further investigate a reinforcing effect of corn oil, we studied whether the corn oil acts as a reinforcer under a progressive ratio (PR) schedule in the operant task. BALB/c mice were trained to lever press for sucrose and corn oil. After reaching a stable break-point for 100% corn oil, the PR test was conducted for various concentrations of corn oil (0%-100%). The reinforcing effect of corn oil was increased in a concentration-dependent manner under the PR schedule. A mineral oil and 0.3% xanthan gum as vehicles did not show any reinforcing effect in the PR test, suggesting that oily and viscous texture was not related to the reinforcing property of corn oil. The break-point for corn oil was attenuated by pretreatment with (-)-sulpiride, a D(2) antagonist, in the PR test. On the other hand, SCH23390, a D(1) antagonist, did not influence the break-point. Furthermore, the pretreatment with (-)-sulpiride or SCH23390 did not influence the intake of corn oil in a one-bottle test for 30 min, suggesting that the dopaminergic system is involved in the reinforcing effect but not the consumption of corn oil in mice. In conclusion, operant response to corn oil is concentration-dependently enhanced under the PR schedule. This reinforcing effect of corn oil is at least partly mediated through the dopaminergic systems via D(2) receptors.

  4. Performance on a strategy set shifting task during adolescence in a genetic model of attention deficit/hyperactivity disorder: Methylphenidate vs. atomoxetine treatments (United States)

    Harvey, Roxann C; Jordan, Chloe J; Tassin, David H; Moody, Kayla R; Dwoskin, Linda P; Kantak, Kathleen M


    Research examining medication effects on set shifting in teens with attention deficit/hyperactivity disorder (ADHD) is lacking. An animal model of ADHD may be useful for exploring this gap. The Spontaneously Hypertensive Rat (SHR) is a commonly used animal model of ADHD. SHR and two comparator strains, Wistar-Kyoto (WKY) and Wistar (WIS), were evaluated during adolescence in a strategy set shifting task under conditions of a 0-sec or 15-sec delay to reinforcer delivery. The task had three phases: initial discrimination, set shift and reversal learning. Under 0-sec delays, SHR performed as well as or better than WKY and WIS. Treatment with 0.3 mg/kg/day atomoxetine had little effect, other than to modestly increase trials to criterion during set shifting in all strains. Under 15-sec delays, SHR had longer lever press reaction times, longer latencies to criterion and more trial omissions than WKY during set shifting and reversal learning. These deficits were not reduced systematically by 1.5 mg/kg/day methylphenidate or 0.3 mg/kg/day atomoxetine. Regarding learning in SHR, methylphenidate improved initial discrimination, whereas atomoxetine improved set shifting but disrupted initial discrimination. During reversal learning, both drugs were ineffective in SHR, and atomoxetine made reaction time and trial omissions greater in WKY. Overall, WIS performance differed from SHR or WKY, depending on phase. Collectively, a genetic model of ADHD in adolescent rats revealed that neither methylphenidate nor atomoxetine mitigated all deficits in SHR during the set shifting task. Thus, methylphenidate or atomoxetine monotherapy may not mitigate all set shift task-related deficits in teens with ADHD. PMID:23376704

  5. Generation and associative encoding in young and old adults: the effect of the strength of association between cues and targets on a cued recall task. (United States)

    Taconnat, Laurence; Froger, Charlotte; Sacher, Mathilde; Isingrini, Michel


    The generation effect (i.e., better recall of the generated items than the read items) was investigated with a between-list design in young and elderly participants. The generation task difficulty was manipulated by varying the strength of association between cues and targets. Overall, strong associates were better recalled than weak associates. However, the results showed different generation effect patterns according to strength of association and age, with a greater generation effect for weak associates in younger adults only. These findings suggest that generating weak associates leads to more elaborated encoding, but that elderly adults cannot use this elaborated encoding as well as younger adults to recall the target words at test.

  6. Sequential modulation of cue use in the task switching paradigm

    Directory of Open Access Journals (Sweden)

    Mike eWendt


    Full Text Available In task switching studies, pre-cuing of the upcoming task improves performance, indicating preparatory activation of the upcoming task set and/or inhibition of the previous task set. To further investigate cue-based task preparation, the authors presented both valid and invalid task cues in a task switching experiment involving three tasks. Consistent with previous findings, a validity effect in terms of higher reaction times on invalidly compared to validly cued tasks was obtained. However, this validity effect was reduced following invalidly cued trials, suggesting dynamic adjustment in terms of decreased cue-based preparation after being misled. Performance was particularly impaired when the current task was the one that was invalidly cued on the preceding trial. This finding may reflect either particular reluctance to prepare or persisting inhibition of the erroneously prepared task set from the pre-trial.

  7. Sequential Modulation of Cue Use in the Task Switching Paradigm (United States)

    Wendt, Mike; Luna-Rodriguez, Aquiles; Reisenauer, Renate; Jacobsen, Thomas; Dreisbach, Gesine


    In task switching studies, pre-cuing of the upcoming task improves performance, indicating preparatory activation of the upcoming task-set, and/or inhibition of the previous task-set. To further investigate cue-based task preparation, the authors presented both valid and invalid task cues in a task switching experiment involving three tasks. Consistent with previous findings, a validity effect in terms of higher reaction times on invalidly compared to validly cued tasks was obtained. However, this validity effect was reduced following invalidly cued trials, suggesting dynamic adjustment in terms of decreased cue-based preparation after being misled. Performance was particularly impaired when the current task was the one that was invalidly cued on the preceding trial. This finding may reflect either particular reluctance to prepare or persisting inhibition of the erroneously prepared task-set from the pre-trial. PMID:22908004

  8. Ethanol exposure interacts with training conditions to influence behavioral adaptation to a negative instrumental contingency

    Directory of Open Access Journals (Sweden)

    Regina A. Mangieri


    Full Text Available We previously reported that, in male, Long Evans rats, instrumental lever pressing that had been reinforced during limited training under a variable interval (VI schedule by oral self-administration of a 10% sucrose/10% ethanol (10S10E solution was insensitive to devaluation of 10S10E. In contrast, lever pressing that had been reinforced under a variable ratio (VR schedule, or by self-administration of 10% sucrose (10S alone, was sensitive to outcome devaluation. The relative insensitivity to outcome devaluation indicated that seeking of 10S10E by the VI-trained rats had become an instrumental habit. In the present study we employed an alternative operational definition of an instrumental habit and compared the effect of reversing the action-outcome contingency on lever press performance by rats trained under the same experimental conditions. Male Long Evans rats received daily operant training, in which lever presses were reinforced by 10S10E or 10S, under VI or VR schedules. After nine sessions of VI or VR training, rats were tested over four sessions in which the instrumental contingency was changed so that a lever press would prevent reinforcer delivery for 120 seconds. We found that rats that had been trained to lever press for 10S10E under the VR schedule showed a greater change in lever pressing across testing sessions than those that had received 10S10E reinforcement under the VI schedule. There was no such interaction with reinforcement schedule for rats that had received only 10S reinforcement during training. These findings are consistent with those of our previous study, and provide further evidence that addition of ethanol to sucrose may promote habitual responding in an instrumental task.

  9. Bond strength of W-Cu/CuCr integrated material

    Institute of Scientific and Technical Information of China (English)

    范志康; 梁淑华; 薛旭


    The bond strength of W-Cu/CuCr integrated material was investigated. The results show that the fracture of W-Cu/CuCr integrated material often takes place at W-Cu/CuCr interface. Some alloying elements enhance the bond of W and CuCr alloy, which results in the increase of the strength of the W-Cu/CuCr interface. And the fracture of the WCu/CuCr integrated material occurs in the CuCr alloy part, not at the W-Cu/CuCr interface. Chromium in CuCr alloy part of the integrated material can improve Cr diffusing from the CuCr alloy to W-Cu composite and can be alloyed (near the W-Cu/CuCr interface) in the W-Cu composite. Thus the strength of W-Cu/CuCr interface is also increased.

  10. The Effect of Composition of Different Ecotoxicological Test Media on Free and Bioavailable Copper from CuSO4 and CuO Nanoparticles: Comparative Evidence from a Cu-Selective Electrode and a Cu-Biosensor

    Directory of Open Access Journals (Sweden)

    Angela Ivask


    Full Text Available The analysis of (bioavailable copper in complex environmental settings, including biological test media, is a challenging task. In this study, we demonstrated the potential of a recombinant Pseudomonas fluorescens-based biosensor for bioavailability analysis of CuSO4 and CuO nanoparticles (nano-CuO in seventeen different ecotoxicological and microbiologial test media. In parallel, free Cu in these test media was analysed using Cu-ion selective electrode (Cu-ISE. In the case of CuSO4, both free and bioavailable Cu decreased greatly with increasing concentration of organics and phosphates in the tested media. A good correlation between free and bioavailable Cu was observed (r = 0.854, p < 0.01 indicating that the free Cu content in biological test media may be a reasonably good predictor for the toxicity of CuSO4. As a proof, it was demonstrated that when eleven EC50 values for CuSO4 from different organisms in different test media were normalized for the free Cu in these media, the difference in these EC50 values was decreased from 4 to 1.8 orders of magnitude. Thus, toxicity of CuSO4 to these organisms was attributed to the properties of the test media rather than to inherent differences in sensitivity between the test organisms. Differently from CuSO4, the amount of free and bioavailable Cu in nano-CuO spiked media was not significantly correlated with the concentration of organics in the test media. Thus, the speciation of nano-CuO in toxicological test systems was not only determined by the complexation of Cu ions but also by differential dissolution of nano-CuO in different test conditions leading to a new speciation equilibrium. In addition, a substantial fraction of nano-CuO that was not detectable by Cu-ISE (i.e., not present as free Cu-ions was bioavailable to Cu-biosensor bacteria. Thus, in environmental hazard analysis of (nano particulate materials, biosensor analysis may be more informative than other analytical techniques. Our

  11. Components of competitor priming in task switching. (United States)

    Teskey, Morgan L; Masson, Michael E J


    Executing an action in response to a stimulus is thought to result in the creation of an event code that integrates stimulus and action features (Allport, 1987; Hommel in Visual Cognition 5: 183-216, 1998). When switching between tasks, competitor priming occurs if a distractor stimulus cues the retrieval of a previously established event code in which that distractor is bound to a competing task, creating a source of interference with the current task whereby the observer is encouraged to apply the competing task to the distractor. We propose a second aspect of competitor priming: the misapplication of the retrieved competing task to the target stimulus. We report two task-switching experiments in which tasks applied to picture-word compound stimuli were manipulated to create conditions in which this second aspect of competitor priming could be revealed and distinguished from other sources of task- and stimulus-based priming. A substantial increase in competitor priming was observed when subjects switched between tasks that required very different processing operations and the competing task was highly relevant to the target stimulus. These results are consistent with our claim that competitor priming can result from applying the competing task either to the distractor that cued it or to the target stimulus.

  12. Modeling Cognitive Strategies during Complex Task Performing Process (United States)

    Mazman, Sacide Guzin; Altun, Arif


    The purpose of this study is to examine individuals' computer based complex task performing processes and strategies in order to determine the reasons of failure by cognitive task analysis method and cued retrospective think aloud with eye movement data. Study group was five senior students from Computer Education and Instructional Technologies…

  13. The influence of action effects in task switching

    Directory of Open Access Journals (Sweden)

    Sarah eLukas


    Full Text Available According to ideomotor theories, intended effects caused by a certain action are anticipated before action execution. In the present study, we examined the question of whether action effects play a role in cued task switching. In our study, the participants practiced task-response-effect mappings in an acquisition phase, in which action effects occur after a response in a certain task context. In the ensuing transfer phase, the previously practiced mappings were changed in a random, unpredictable task-response-effect mapping. When changed into unpredictable action effects, RT as well as switch costs increased, but this occurred mainly in trials with short preparation time and not with long preparation time. Moreover, switch costs were generally smaller with predictable action effects than with unpredictable action effects. This suggests that anticipated task-specific action effects help to activate the relevant task set before task execution when the task is not yet already prepared based on the cue.

  14. "Task" as Research Construct (United States)

    Seedhouse, Paul


    The article examines "task" as research construct as predominantly conceived in terms of task-as-workplan in the task-based learning/second language acquisition literature. It is suggested that "task" has weak construct validity and ontology in an overwhelmingly quantitative paradigm because the construct has a "split personality."…

  15. Examination of the Role of Expectancies on Task Performance in College Students Concerned about ADHD. (United States)

    Wei, Christina; Suhr, Julie A


    Prior research has shown that performance on cognitive tasks can be influenced by expectations (Smith & Sullivan, 2003 ; Suhr & Gunstad, 2002 , 2005 ). The current study examined whether cuing a belief about the diagnostic saliency of a cognitive task among young adults who expressed concern about having attention-deficit hyperactivity disorder (ADHD) influenced task performance. Participants were randomly assigned to either receive neutral directions or be cued to a belief that the task had diagnostic saliency prior to completing a working-memory task. Supporting our hypothesis, college students with higher prestudy report of ADHD symptoms who were cued with a belief about the diagnostic saliency of the task performed worse compared with students who received neutral instructions. As many researchers and clinicians currently rely exclusively on self-reported symptoms and neuropsychological tests to diagnose ADHD, our findings highlight the importance of comprehensive assessment for provision of appropriate clinical services to adults presenting with ADHD concerns.

  16. Recalling academic tasks (United States)

    Draper, Franklin Gno

    This study was focused on what students remembered about five middle school science tasks when they were juniors and seniors in high school. Descriptions of the five tasks were reconstructed from available artifacts and teachers' records, notes and recollections. Three of the five tasks were "authentic" in the sense that students were asked to duplicate the decisions practitioners make in the adult world. The other two tasks were more typical school tasks involving note taking and preparation for a quiz. All five tasks, however, involved use of computers. Students were interviewed to examine what and how well they recalled the tasks and what forms or patterns of recall existed. Analysis of their responses indicated that different kinds of tasks produced different levels of recall. Authentically situated tasks were remembered much better than routine school tasks. Further, authentic tasks centered on design elements were recalled better than those for which design was not as pivotal. Patterns of recall indicated that participants most often recalled the decisions they made, the scenarios of the authentically situated tasks, the consequences of their tasks and the social contexts of the classroom. Task events, in other words, appeared to form a framework upon which students constructed stories of the tasks. The more salient the events, the richer the story, the deeper and more detailed the recall of the task. Thus, authentic tasks appeared to lend themselves to creating stories better than regular school tasks and therefore such tasks were recalled better. Implications of these patterns of recall are discussed with respect to issues of school learning and assessment.

  17. Kokkos? Task DAG Capabilities.

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Harold C.; Ibanez, Daniel Alejandro


    This report documents the ASC/ATDM Kokkos deliverable "Production Portable Dy- namic Task DAG Capability." This capability enables applications to create and execute a dynamic task DAG ; a collection of heterogeneous computational tasks with a directed acyclic graph (DAG) of "execute after" dependencies where tasks and their dependencies are dynamically created and destroyed as tasks execute. The Kokkos task scheduler executes the dynamic task DAG on the target execution resource; e.g. a multicore CPU, a manycore CPU such as Intel's Knights Landing (KNL), or an NVIDIA GPU. Several major technical challenges had to be addressed during development of Kokkos' Task DAG capability: (1) portability to a GPU with it's simplified hardware and micro- runtime, (2) thread-scalable memory allocation and deallocation from a bounded pool of memory, (3) thread-scalable scheduler for dynamic task DAG, (4) usability by applications.

  18. Set shifting training with categorization tasks.

    Directory of Open Access Journals (Sweden)

    Anna Soveri

    Full Text Available The very few cognitive training studies targeting an important executive function, set shifting, have reported performance improvements that also generalized to untrained tasks. The present randomized controlled trial extends set shifting training research by comparing previously used cued training with uncued training. A computerized adaptation of the Wisconsin Card Sorting Test was utilized as the training task in a pretest-posttest experimental design involving three groups of university students. One group received uncued training (n = 14, another received cued training (n = 14 and the control group (n = 14 only participated in pre- and posttests. The uncued training group showed posttraining performance increases on their training task, but neither training group showed statistically significant transfer effects. Nevertheless, comparison of effect sizes for transfer effects indicated that our results did not differ significantly from the previous studies. Our results suggest that the cognitive effects of computerized set shifting training are mostly task-specific, and would preclude any robust generalization effects with this training.

  19. Cu-67 Photonuclear Production (United States)

    Starovoitova, Valeriia; Foote, Davy; Harris, Jason; Makarashvili, Vakhtang; Segebade, Christian R.; Sinha, Vaibhav; Wells, Douglas P.


    Cu-67 is considered as one of the most promising radioisotopes for cancer therapy with monoclonal antibodies. Current production schemes using high-flux reactors and cyclotrons do not meet potential market need. In this paper we discuss Cu-67 photonuclear production through the reaction Zn-68(γ,p)Cu-67. Computer simulations were done together with experiments to study and optimize Cu-67 yield in natural Zn target. The data confirms that the photonuclear method has potential to produce large quantities of the isotope with sufficient purity to be used in medical field.

  20. Cu(I)/Cu(II) templated functional pseudorotaxanes and rotaxanes

    Indian Academy of Sciences (India)

    Subrata Saha; Pradyut Ghosh


    Threaded complexes like pseudorotaxanes, rotaxanes based on Cu(I)/Cu(II) ions have shown to be promising for the construction of mechanically interlocked molecular-level architectures. In this short review, we focus on the synthetic strategies developed to construct pseudorotaxanes and rotaxanes using Cu(I)/Cu(II) ions as template. Further, brief discussions on chemical and mechanical properties associated with some of the selected to Cu(I)/Cu(II) based pseudorotaxanes and rotaxanes are presented.

  1. Project Tasks in Robotics

    DEFF Research Database (Denmark)

    Sørensen, Torben; Hansen, Poul Erik


    Description of the compulsary project tasks to be carried out as a part of DTU course 72238 Robotics......Description of the compulsary project tasks to be carried out as a part of DTU course 72238 Robotics...

  2. Launching Complex Tasks (United States)

    Jackson, Kara J.; Shahan, Emily C.; Gibbons, Lynsey K.; Cobb, Paul A.


    Mathematics lessons can take a variety of formats. In this article, the authors discuss lessons organized around complex mathematical tasks. These lessons usually unfold in three phases. First, the task is introduced to students. Second, students work on solving the task. Third, the teacher "orchestrates" a concluding whole-class discussion in…

  3. Task assignment and coaching

    NARCIS (Netherlands)

    Dominguez-Martinez, S.


    An important task of a manager is to motivate her subordinates. One way in which a manager can give incentives to junior employees is through the assignment of tasks. How a manager allocates tasks in an organization, provides information to the junior employees about his ability. Without coaching fr

  4. A Task Analytic Process to Define Future Concepts in Aviation (United States)

    Gore, Brian Francis; Wolter, Cynthia A.


    A necessary step when developing next generation systems is to understand the tasks that operators will perform. One NextGen concept under evaluation termed Single Pilot Operations (SPO) is designed to improve the efficiency of airline operations. One SPO concept includes a Pilot on Board (PoB), a Ground Station Operator (GSO), and automation. A number of procedural changes are likely to result when such changes in roles and responsibilities are undertaken. Automation is expected to relieve the PoB and GSO of some tasks (e.g. radio frequency changes, loading expected arrival information). A major difference in the SPO environment is the shift to communication-cued crosschecks (verbal / automated) rather than movement-cued crosschecks that occur in a shared cockpit. The current article highlights a task analytic process of the roles and responsibilities between a PoB, an approach-phase GSO, and automation.

  5. Heimdall System for MSSS Sensor Tasking (United States)

    Herz, A.; Jones, B.; Herz, E.; George, D.; Axelrad, P.; Gehly, S.

    In Norse Mythology, Heimdall uses his foreknowledge and keen eyesight to keep watch for disaster from his home near the Rainbow Bridge. Orbit Logic and the Colorado Center for Astrodynamics Research (CCAR) at the University of Colorado (CU) have developed the Heimdall System to schedule observations of known and uncharacterized objects and search for new objects from the Maui Space Surveillance Site. Heimdall addresses the current need for automated and optimized SSA sensor tasking driven by factors associated with improved space object catalog maintenance. Orbit Logic and CU developed an initial baseline prototype SSA sensor tasking capability for select sensors at the Maui Space Surveillance Site (MSSS) using STK and STK Scheduler, and then added a new Track Prioritization Component for FiSST-inspired computations for predicted Information Gain and Probability of Detection, and a new SSA-specific Figure-of-Merit (FOM) for optimized SSA sensor tasking. While the baseline prototype addresses automation and some of the multi-sensor tasking optimization, the SSA-improved prototype addresses all of the key elements required for improved tasking leading to enhanced object catalog maintenance. The Heimdall proof-of-concept was demonstrated for MSSS SSA sensor tasking for a 24 hour period to attempt observations of all operational satellites in the unclassified NORAD catalog, observe a small set of high priority GEO targets every 30 minutes, make a sky survey of the GEO belt region accessible to MSSS sensors, and observe particular GEO regions that have a high probability of finding new objects with any excess sensor time. This Heimdall prototype software paves the way for further R&D that will integrate this technology into the MSSS systems for operational scheduling, improve the software's scalability, and further tune and enhance schedule optimization. The Heimdall software for SSA sensor tasking provides greatly improved performance over manual tasking, improved

  6. What Task Designers Do. (United States)

    Johnson, Keith


    Describes a research project that is concerned with the design procedures followed by those engaged in designing pedagogic tasks for use in classrooms. Focuses on the part of the project that involves actual observation of designers in the process of developing one specific task for class use. Findings are presented under three headers: control…

  7. Supporting complex search tasks

    DEFF Research Database (Denmark)

    Gäde, Maria; Hall, Mark; Huurdeman, Hugo


    There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks, is fragme......There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks......, and recommendations, and supporting exploratory search to sensemaking and analytics, UI and UX design pose an overconstrained challenge. How do we know that our approach is any good? Supporting complex search task requires new collaborations across the whole field of IR, and the proposed workshop will bring together...

  8. Supporting complex search tasks

    DEFF Research Database (Denmark)

    Gäde, Maria; Hall, Mark; Huurdeman, Hugo;


    There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks......, is fragmented at best. The workshop addressed the many open research questions: What are the obvious use cases and applications of complex search? What are essential features of work tasks and search tasks to take into account? And how do these evolve over time? With a multitude of information, varying from...... introductory to specialized, and from authoritative to speculative or opinionated, when to show what sources of information? How does the information seeking process evolve and what are relevant differences between different stages? With complex task and search process management, blending searching, browsing...

  9. Reading Comprehension of an Inferential Text by Deaf Students with Cochlear Implants Using Cued Speech (United States)

    Torres, Santiago; Rodriguez, Jose-Miguel; Garcia-Orza, Javier; Calleja, Marina


    The aim of this study was to explore the ability of children who are profoundly deaf to reach high levels of reading proficiency on an inferential reading task. In an experimental narrative reading task, four children with prelingual hearing loss who used cued speech (MOC group) were compared with 58 students with typical hearing: 30 peers at the…

  10. Task-baseret kommunikativ sprogundervisning

    DEFF Research Database (Denmark)

    Pedersen, Michael Svendsen


    Definition af task-baseret sprogundervisning, kriterier for task. Forskning i Second Language Acquisition med brug af task, tilrettelæggelse af task-baseret kommunikativ undervisning. Begrænsninger i og perspektiver for videreudvikling af task-baseret sprogundervising-......Definition af task-baseret sprogundervisning, kriterier for task. Forskning i Second Language Acquisition med brug af task, tilrettelæggelse af task-baseret kommunikativ undervisning. Begrænsninger i og perspektiver for videreudvikling af task-baseret sprogundervising-...

  11. /Cu-Al System (United States)

    Kish, Orel; Froumin, Natalya; Aizenshtein, Michael; Frage, Nachum


    Wettability and interfacial interaction of the Ta2O5/Cu-Al system were studied. Pure Cu does not wet the Ta2O5 substrate, and improved spreading is achieved when relatively a high fraction of the active element (~40 at.% Al) was added. The Al2O3 and AlTaO4 phases were observed at the Ta2O5/Cu-Al interface. A thermodynamic evaluation allowed us to suggest that the lack of wetting bellow 40 at.% Al is due to the presence of a native oxide, which covers the drop. The conditions of the native oxide decomposition and the formation of the volatile Al2O suboxide strongly depend on the vacuum level during sessile drop experiments and the composition of the Cu-Al alloy. In our case, Al contents greater than 40% provides thermodynamic conditions for the formation of Al2O (as a result of Al reaction with Al2O3) and the drop spreading. It was suggested that the final contact angle in the Ta2O5/Cu-Al system (50°) is determined by Ta adsorption on the newly formed alumina interlayer.

  12. Effects of state anxiety on performance using a task-switching paradigm: an investigation of attentional control theory. (United States)

    Derakshan, Nazanin; Smyth, Sinéad; Eysenck, Michael W


    Low- and high-anxious participants performed arithmetical tasks under task-switching or nontask-switching conditions. These tasks were low or high in complexity. The task on each trial was either explicitly cued or not cued. We assumed that demands on attentional control would be greater in the task-switching condition than in the nontask-switching condition, and would be greater with high-complexity tasks than with low-complexity ones. We also assumed that demands on attentional control would be greater when cues were absent rather than present. According to attentional control theory (Eysenck, Derakshan, Santos, & Calvo, 2007), anxiety impairs attentional control processes required to shift attention optimally within and between tasks. We predicted that there would be greater negative effects of high state anxiety in the task-switching condition than in the nontask-switching condition. Our theoretical predictions were supported, suggesting that state anxiety reduces attentional control.

  13. Energy Efficient Task Light

    DEFF Research Database (Denmark)

    Logadottir, Asta; Ardkapan, Siamak Rahimi; Johnsen, Kjeld


    The objectives of this work is to develop a task light for office lighting that fulfils the minimum requirements of the European standard EN12464 - 1 : Light and lighting – Lighting of work places, Part 1: Indoor workplaces and the Danish standard DS 700 : Lys og belysning I arbejdsrum , or more...... specifically the requirements that apply to the work area and the immediate surrounding area. By providing a task light that fulfils the requirements for task lighting and the immediate surrounding area, the general lighting only needs to provide the illuminance levels required for background lighting...... and thereby a reduction in installed power for general lighting of about 40 % compared to the way illuminance levels are designed in an office environment in Denmark today. This lighting strategy is useful when the placement of the task area is not defined in the space before the lighting is design ed...

  14. Organizing Core Tasks

    DEFF Research Database (Denmark)

    Boll, Karen

    Civil servants conduct the work which makes welfare states functions on an everyday bases: Police men police, school teachers teach, and tax inspectors inspect. Focus in this paper is on the core tasks of tax inspectors. The paper argues that their core task of securing the collection of revenue...... has remained much the same within the last 10 years. However, how the core task has been organized has changed considerable under the influence of various “organizing devices”. The paper focusses on how organizing devices such as risk assessment, output-focus, effect orientation, and treatment...... projects influence the organization of core tasks within the tax administration. The paper shows that the organizational transformations based on the use of these devices have had consequences both for the overall collection of revenue and for the employees’ feeling of “making a difference”. All in all...

  15. PRR performance of Cu- and CuBr-vapor lasers (United States)

    Fedorov, V. F.; Evtushenko, Gennadiy S.; Klimkin, Vladimir M.; Polunin, Yu. P.; Soldatov, Anatoly N.; Sukhanov, Viktor B.


    Results obtained from comparative analysis of the pulse repetition rate performance of Cu- and CuBr-vapor lasers operated at high pump pulse repetitions (approximately 100 kHz) are reported. For a CuBr laser with a 8 mm diameter discharge tube the laser pulse repetition rate as high as 270 kHz was realized.

  16. Cu Diffusion in Co/Cu/TiN Films for Cu Metallization

    Institute of Scientific and Technical Information of China (English)

    Xiuhua CHEN; Xinghui WU; Jinzhong XIANG; Zhenlai ZHOU; Heyun ZHAO; Liqiang CHEN


    Some information on how to use in-situ determined diffusion coefficient of Cu to make barrier layer of Cu metallization in ultra large scale integrations (ULSIs) was provided. Diffusion coefficients of Cu in Co at low temperature were determined to analyze Cu migration to Co surface layer. The diffusion depths were analyzed using X-ray photoelectron spectroscopy (XPS) depth profile to investigate the diffusion effect of Cu in Co at different temperatures. The possible pretreatment temperature and time of barrier layer can be predicted according to the diffusion coefficients of Cu in Co.

  17. What are task-sets: a single, integrated representation or a collection of multiple control representations?

    Directory of Open Access Journals (Sweden)

    Dragan eRangelov


    Full Text Available Performing two randomly alternating tasks typically results in higher reaction times (RTs following a task switch, relative to a task repetition. These task switch costs (TSC reflect processes of switching between control settings for different tasks. The present study investigated whether task sets operate as a single, integrated representation or as an agglomeration of relatively independent components. In a cued task switch paradigm, target detection (present/absent and discrimination (blue/green/right-/left-tilted tasks alternated randomly across trials. The target was either a color or an orientation singleton among homogeneous distractors. Across two trials, the task and target-defining dimension repeated or changed randomly. For task switch trials, agglomerated task sets predict a difference between dimension changes and repetitions: joint task and dimension switches require full task set reconfiguration, while dimension repetitions permit re-using some control settings from the previous trial. By contrast, integrated task sets always require full switches, predicting dimension repetition effects (DREs to be absent across task switches. RT analyses showed significant DREs across task switches as well as repetitions supporting the notion of agglomerated task sets. Additionally, two event-related potentials (ERP were analyzed: the Posterior-Contralateral-Negativity (PCN indexing spatial selection dynamics, and the Sustained-Posterior-Contralateral-Negativity (SPCN indexing post-selective perceptual/semantic analysis. Significant DREs across task switches were observed for both the PCN and SPCN components. Together, DREs across task switches for RTs and two functionally distinct ERP components suggest that re-using control settings across different tasks is possible. The results thus support the ‘agglomerated-task-set’ hypothesis, and are inconsistent with ‘integrated task sets’.

  18. Task Switching in a Hierarchical Task Structure: Evidence for the Fragility of the Task Repetition Benefit (United States)

    Lien, Mei-Ching; Ruthruff, Eric


    This study examined how task switching is affected by hierarchical task organization. Traditional task-switching studies, which use a constant temporal and spatial distance between each task element (defined as a stimulus requiring a response), promote a flat task structure. Using this approach, Experiment 1 revealed a large switch cost of 238 ms.…

  19. Board Task Performance

    DEFF Research Database (Denmark)

    Minichilli, Alessandro; Zattoni, Alessandro; Nielsen, Sabina


    This paper addresses recent calls to narrow the micro–macro gap in management research (Bamberger, 2008), by incorporating a macro-level context variable (country) in exploring micro-level determinants of board effectiveness. Following the integrated model proposed by Forbes and Milliken (1999), we...... identify three board processes as micro-level determinants of board effectiveness. Specifically, we focus on effort norms, cognitive conflicts and the use of knowledge and skills as determinants of board control and advisory task performance. Further, we consider how two different institutional settings...... influence board tasks, and how the context moderates the relationship between processes and tasks. Our hypotheses are tested on a survey-based dataset of 535 medium-sized and large industrial firms in Italy and Norway, which are considered to substantially differ along legal and cultural dimensions...

  20. Goal orientation, perceived task outcome and task demands in mathematics tasks: effects on students' attitude in actual task settings. (United States)

    Seegers, Gerard; van Putten, Cornelis M; de Brabander, Cornelis J


    In earlier studies, it has been found that students' domain-specific cognitions and personal learning goals (goal orientation) influence task-specific appraisals of actual learning tasks. The relations between domain-specific and task-specific variables have been specified in the model of adaptive learning. In this study, additional influences, i.e., perceived task outcome on a former occasion and variations in task demands, were investigated. The purpose of this study was to identify personality and situational variables that mediate students' attitude when confronted with a mathematics task. Students worked on a mathematics task in two subsequent sessions. Effects of perceived task outcome at the first session on students' attitude at the second session were investigated. In addition, we investigated how differences in task demands influenced students' attitude. Variations in task demands were provoked by different conditions in task-instruction. In one condition, students were told that the result on the test would add to their mark on mathematics. This outcome orienting condition was contrasted with a task-orienting condition where students were told that the results on the test would not be used to give individual grades. Participants were sixth grade students (N = 345; aged 11-12 years) from 14 primary schools. Multivariate and univariate analyses of (co)variance were applied to the data. Independent variables were goal orientation, task demands, and perceived task outcome, with task-specific variables (estimated competence for the task, task attraction, task relevance, and willingness to invest effort) as the dependent variables. The results showed that previous perceived task outcome had a substantial impact on students' attitude. Additional but smaller effects were found for variation in task demands. Furthermore, effects of previous perceived task outcome and task demands were related to goal orientation. The resulting pattern confirmed that, in general

  1. Disentangling attention from action in the emotional spatial cueing task. (United States)

    Mulckhuyse, Manon; Crombez, Geert


    In the emotional spatial cueing task, a peripheral cue--either emotional or non-emotional--is presented before target onset. A stronger cue validity effect with an emotional relative to a non-emotional cue (i.e., more efficient responding to validly cued targets relative to invalidly cued targets) is taken as an indication of emotional modulation of attentional processes. However, results from previous emotional spatial cueing studies are not consistent. Some studies find an effect at the validly cued location (shorter reaction times compared to a non-emotional cue), whereas other studies find an effect at the invalidly cued location (longer reaction times compared to a non-emotional cue). In the current paper, we explore which parameters affect emotional modulation of the cue validity effect in the spatial cueing task. Results from five experiments in healthy volunteers led to the conclusion that a threatening spatial cue did not affect attention processes but rather indicate that motor processes are affected. A possible mechanism might be that a strong aversive cue stimulus decreases reaction times by means of stronger action preparation. Consequently, in case of a spatially congruent response with the peripheral cue, a stronger cue validity effect could be obtained due to stronger response priming. The implications for future research are discussed.

  2. Algebra task & drill sheets

    CERN Document Server

    Reed, Nat


    For grades 6-8, our State Standards-based combined resource meets the algebraic concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. The task sheets introduce the mathematical concepts to the students around a central problem taken from real-life experiences, while the drill sheets provide warm-up and timed practice questions for the students to strengthen their procedural proficiency skills. Included are opportunities for problem-solving, patterning, algebraic graphing, equations and determining averages. The combined task & drill sheets

  3. Algebra task & drill sheets

    CERN Document Server

    Reed, Nat


    For grades 3-5, our State Standards-based combined resource meets the algebraic concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. The task sheets introduce the mathematical concepts to the students around a central problem taken from real-life experiences, while the drill sheets provide warm-up and timed practice questions for the students to strengthen their procedural proficiency skills. Included are opportunities for problem-solving, patterning, algebraic graphing, equations and determining averages. The combined task & drill sheets

  4. Task-Based Learning: The Interaction between Tasks and Learners. (United States)

    Murphy, Jacky


    Investigates the relationship between tasks and learners in task-based learning. Findings suggest that manipulation of task characteristics and conditions may not achieve the intended pedagogic outcomes, and that new ways are needed to focus learners' attention of form without sacrificing the meaning-driven principles of task-based learning.…

  5. A Daunting Task Still

    Institute of Scientific and Technical Information of China (English)



    @@ Despite steady economic growth for three decades, China is still a developing country facing daunting poverty alleviation tasks. According to the poverty line of 1,196 yuan ($176) per capita net income in a year set in March 2009, the country still has a poverty population of more than 40 million, mainly living in rural areas.

  6. Task 1 quarternary tectonics

    Energy Technology Data Exchange (ETDEWEB)

    Bell, J.W.


    Activities on the task of quarternary tectonics for the Yucca Mountain Site investigations are described. Technical topics include: A preliminary reveiw of Bare Mountain Trench; A preliminary detailed lineament map of the Southwestern part of the proposed repository; A discussion on the 1994 Double Spring Flat, Nevada earthquake; and evidence for temporal clustering.

  7. Can tasks be inherently boring? (United States)

    Charney, Evan


    Kurzban et al. argue that the experiences of "effort," "boredom," and "fatigue" are indications that the costs of a task outweigh its benefits. Reducing the costs of tasks to "opportunity costs" has the effect of rendering tasks costless and of denying that they can be inherently boring or tedious, something that "vigilance tasks" were intentionally designed to be.

  8. Parietal lesion effects on cued recall following pair associate learning. (United States)

    Ben-Zvi, Shir; Soroker, Nachum; Levy, Daniel A


    We investigated the involvement of the posterior parietal cortex in episodic memory in a lesion-effects study of cued recall following pair-associate learning. Groups of patients who had experienced first-incident stroke, generally in middle cerebral artery territory, and exhibited damage that included lateral posterior parietal regions, were tested within an early post-stroke time window. In three experiments, patients and matched healthy comparison groups executed repeated study and cued recall test blocks of pairs of words (Experiment 1), pairs of object pictures (Experiment 2), or pairs of object pictures and environmental sounds (Experiment 3). Patients' brain CT scans were subjected to quantitative analysis of lesion volumes. Behavioral and lesion data were used to compute correlations between area lesion extent and memory deficits, and to conduct voxel-based lesion-symptom mapping. These analyses implicated lateral ventral parietal cortex, especially the angular gyrus, in cued recall deficits, most pronouncedly in the cross-modal picture-sound pairs task, though significant parietal lesion effects were also found in the unimodal word pairs and picture pairs tasks. In contrast to an earlier study in which comparable parietal lesions did not cause deficits in item recognition, these results indicate that lateral posterior parietal areas make a substantive contribution to demanding forms of recollective retrieval as represented by cued recall, especially for complex associative representations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Structure-dependent size effects in CuTa/Cu nanolaminates

    Energy Technology Data Exchange (ETDEWEB)

    Gu, C. [State-Key Laboratory for Mechanical Behavior of Material, Xi’an Jiaotong University Xi’an, 710049 (China); Wang, F., E-mail: [State Key Laboratory for Strength and Vibration of Mechanical Structures, Xian Jiaotong University Xi’an, 710049 (China); Huang, P., E-mail: [State-Key Laboratory for Mechanical Behavior of Material, Xi’an Jiaotong University Xi’an, 710049 (China); Xu, K.W. [State-Key Laboratory for Mechanical Behavior of Material, Xi’an Jiaotong University Xi’an, 710049 (China); Lu, T.J. [State Key Laboratory for Strength and Vibration of Mechanical Structures, Xian Jiaotong University Xi’an, 710049 (China)


    CuTa monolayers with different Ta contents (34 at% and 37 at%) and CuTa/Cu multilayers with varying nanoscale Cu layer thickness (3–24 nm) were prepared by magnetron sputtering. Their microstructure and mechanical properties were investigated by means of high resolution transmission electron microscopy (HRTEM) and nanoindentation testing. The microstructure of CuTa34 was pure amorphous phase while that of CuTa37 was amorphous phase embedded with nanoparticles. Adding Cu layers into the two different CuTa monolayers led to CuTa-Cu interfaces with different microstructures. For CuTa34/Cu, the interface was relatively straight and the Cu layers exhibited textured growth. For CuTa37/Cu, the interface was wavy and GBs (grain boundaries) were formed in the Cu layers. To investigate the influence of the two different microstructures on multilayer deformation, the residue indentation morphologies of CuTa/Cu were observed under scanning electronic microscope (SEM). For both CuTa34/Cu and CuTa37/Cu, SBs (shear bands) could be effectively inhibited if the Cu layers had a proper thickness. Dominant deformation mechanisms and size effects were proposed and discussed for CuTa/Cu thin films possessing different interfaces and Cu layer structures.

  10. More Attention to Attention? An Eye-Tracking Investigation of Selection of Perceptual Attributes during a Task Switch (United States)

    Longman, Cai S.; Lavric, Aureliu; Monsell, Stephen


    Switching tasks prolongs response times, an effect reduced but not eliminated by active preparation. To explore the role of attentional selection of the relevant stimulus attribute in these task-switch costs, we measured eye fixations in participants cued to identify either a face or a letter displayed on its forehead. With only 200 ms between cue…

  11. Magnetic Moment of $^{59}$Cu

    CERN Multimedia


    Experiment IS358 uses the intense and pure beams of copper isotopes provided by the ISOLDE RILIS (resonance ionization laser ion source). The isotopes are implanted and oriented in the low temperature nuclear orientation set-up NICOLE. Magnetic moments are measured by $\\beta$-NMR. Copper (Z=29), with a single proton above the proton-magic nickel isotopes provides an ideal testground for precise shell model calculations of magnetic moments and their experimental verification. In the course of our experiments we already determined the magnetic moments of $^{67}$Ni, $^{67}$Cu, $^{68g}$Cu, $^{69}$Cu and $^{71}$Cu which provide important information on the magicity of the N=40 subshell closure. In 2001 we plan to conclude our systematic investigations by measuring the magnetic moment of the neutron-deficient isotope $^{59}$Cu. This will pave the way for a subsequent study of the magnetic moment of $^{57}$Cu with a complementary method.

  12. Performing Task Integration

    DEFF Research Database (Denmark)

    Elkjaer, Bente; Nickelsen, Niels Christian Mossfeldt

    . Here cross-professional coordination of work was done by scheduled communication twice a day. When we proposed a way for further integration of tasks through an all-inclusive team organization, we were met with resistance. We use the study to discuss whether relational coordination theory is able to do......In the paper, we deal with how to organize work for cross-professional knowledge sharing. We do so inspired by relational coordination theory, which is affiliated with positive organizational scholarship. Relational coordination theory is constituted by a combination of relationships marked...... away with differences regarding task definitions and working conditions as well as professional knowledge hierarchies and responsibilities for parts and wholes....

  13. Features or tasks?

    DEFF Research Database (Denmark)

    Heilesen, Simon

    In this paper for the Workshop on Human-computer interaction and e-learning, NordiCHI 2002, the author argues that in developing innovative E-learning systems, especially if constructivist pedagogy is to be applied, it will be useful to model the user interface on the often complex tasks...... that the user has to perform rather than just focusing on technical features (and adapting system use to them)....

  14. Gap Task Force

    CERN Multimedia

    Lissuaer, D

    One of the more congested areas in the ATLAS detector is the GAP region (the area between the Barrel Calorimeter and the End Cap calorimeter) where Inner Detector services, LAr Services and some Tile services all must co-habitat in a very limited area. It has been clear for some time that the space in the GAP region is not sufficient to accommodate all that is needed. In the last few month additional problems of routing all the services to Z=0 have been encountered due to the very limited space between the Tile Calorimeter and the first layer of Muon chambers. The Technical Management Board (TMB) and the Executive Board (EB) decided in the middle of March to establish a Task Force to look at this problem and come up with a solution within well-specified guidelines. The task force consisted of experts from the ID, Muon, Liquid Argon and Tile systems in addition to experts from the Technical Coordination team and the Physics coordinator. The task force held many meetings and in general there were some very l...

  15. Mobile Thread Task Manager (United States)

    Clement, Bradley J.; Estlin, Tara A.; Bornstein, Benjamin J.


    The Mobile Thread Task Manager (MTTM) is being applied to parallelizing existing flight software to understand the benefits and to develop new techniques and architectural concepts for adapting software to multicore architectures. It allocates and load-balances tasks for a group of threads that migrate across processors to improve cache performance. In order to balance-load across threads, the MTTM augments a basic map-reduce strategy to draw jobs from a global queue. In a multicore processor, memory may be "homed" to the cache of a specific processor and must be accessed from that processor. The MTTB architecture wraps access to data with thread management to move threads to the home processor for that data so that the computation follows the data in an attempt to avoid L2 cache misses. Cache homing is also handled by a memory manager that translates identifiers to processor IDs where the data will be homed (according to rules defined by the user). The user can also specify the number of threads and processors separately, which is important for tuning performance for different patterns of computation and memory access. MTTM efficiently processes tasks in parallel on a multiprocessor computer. It also provides an interface to make it easier to adapt existing software to a multiprocessor environment.

  16. Low-frequency transcranial magnetic stimulation over left dorsal premotor cortex improves the dynamic control of visuospatially cued actions

    DEFF Research Database (Denmark)

    Ward, Nick S; Bestmann, Sven; Hartwigsen, Gesa


    responses in invalidly cued trials. After real rTMS, task-related activity of the stimulated left rPMd showed increased task-related coupling with activity in ipsilateral SMG and the adjacent anterior intraparietal area (AIP). Individuals who showed a stronger increase in left-hemispheric premotor-parietal...

  17. Animal neuropsychology: validation of the Intra-Dimensional Extra-Dimensional set shifting task for mice. (United States)

    Garner, Joseph P; Thogerson, Collette M; Würbel, Hanno; Murray, James D; Mench, Joy A


    Research in animal neuropsychology is providing an exciting new generation of behavioral tests for mice that promise to overcome many of the limitations of current high-throughput testing, and provide direct animal homologues of clinically important measures in human research. Set shifting tasks are some of the best understood and widely used human neuropsychological tasks, with clinical relevance to traumatic brain injury, schizophrenia, autism, obsessive compulsive disorder, trichotillomania, and many other disorders. Here we report the first successful modification of a human set shifting neuropsychological task, the Intra-Dimensional Extra-Dimensional (IDED) task, for use with mice. We presented mice with a series of compound discrimination and reversal tasks where one stimulus dimension consistently cued reward. Task performance improved with a new set of compound stimuli, as did reversal performance--indicating the formation of a cognitive-attentional set. We then overtrained a subset of the mice, and presented control and overtrained mice with a new compound discrimination where a novel stimulus dimension cued reward. As is the case in human control subjects, control mice persisted in responding to the now-incorrect stimulus dimension, performing poorly on this extra-dimensional shift compared with the previous intra-dimensional shift, thereby validating the task as a measure of set shifting. Furthermore, overtrained mice were impaired on this extra-dimensional shift compared with controls, further validating the task. The advantages and disadvantages of the IDED task compared to high-throughput approaches are discussed.

  18. Task Dominance Determines Backward Inhibition in Task Switching

    Directory of Open Access Journals (Sweden)

    Kerstin Jost


    Full Text Available Switching between tasks is assumed to be accompanied by inhibiting currently irrelevant, but competing tasks. A dominant task that strongly interferes with performing a weaker task may receive especially strong inhibition. We tested this prediction by letting participants switch among three tasks that differ in dominance: a location discrimination task with strong stimulus–response bindings (responding with left-hand and right-hand button presses to stimuli presented left or right to the fixation cross was combined with a color/pattern and a shape discrimination task, for which stimulus–response mappings were arbitrary (e.g., left-hand button press mapped to a red stimulus. Across three experiments, the dominance of the location task was documented by faster and more accurate responses than in the other tasks. This even held for incompatible stimulus–response mappings (i.e., right-hand response to a left-presented stimulus and vice versa, indicating that set-level compatibility (i.e., “dimension overlap” was sufficient for making this location task dominant. As a behavioral marker for backward inhibition, we utilized n-2 repetition costs that are defined by higher reaction times for a switch back to a just abandoned and thus just inhibited task (ABA sequence than for a switch to a less recently inhibited task (CBA, n-2 non-repetition. Reliable n-2 task repetition costs were obtained for all three tasks. Importantly, these costs were largest for the location task, suggesting that inhibition indeed was stronger for the dominant task. This finding adds to other evidence that the amount of inhibition is adjusted in a context-sensitive way.

  19. Calorimetry Task Force Report

    CERN Document Server

    Abdullin, Salavat; Banerjee, Sunanda; Beauceron, Stephanie; Beaudette, Florian; Bhatti, Anwar; Chlebana, Frank; Cossutti, Fabio; Hirschauer, James; Ivanchenko, V; Jang, Dong Wook; Jun, Soon Yung; Kunori, Shuichi; Kroeger, Rob; Liu, Yanwen; Moeller, Anthony; Paulini, Manfred; Piperov, Stefan; Rahmat, Rahmat; Rovelli, Chiara; Safronov, Grigory; Sharma, Seema; Spiropulu, Maria; Yetkin, Taylan


    In this note we summarize the progress made by the calorimeter simulation task force (CaloTF) over the past year. The CaloTF was established in February 2008 in order to understand and reconcile the discrepancies observed between the CMS calorimetry simulation and test beam data recorded during 2004 and 2006. The simulation has been significantly improved by using a newer version of Geant4 and an improved physics list for the full CMS detector simulation. Simulation times have been reduced by introducing flexible parameterizations to describe showering in the calorimeter (using a Gflash-like approach) which have been tuned to the test beam data.

  20. Quarternary tectonics, Task 1

    Energy Technology Data Exchange (ETDEWEB)

    Bell, J.W.


    Activities conducted for the evaluation of the geology and seismotectonics stability of Yucca Mountain as a potential site for the underground disposal of high-level radioactive wastes continued. Tasks concerned with quaternary tectonics include: scheduling of photography of Little Skull Mountain area; the collection and dating of rock varnish samples from the 1932 Cedar Mountain earthquake area for carbon 14 AMS and cation-ratio analysis; collection of samples for thermoluminescence dating from the 1932 Cedar Mountain earthquake area; mapping of the northern area of Crater Flat; and surveying of the May 17, 1993 Eureka the Valley earthquake area.

  1. Beta decay of Cu-56

    NARCIS (Netherlands)

    Borcea, R; Aysto, J; Caurier, E; Dendooven, P; Doring, J; Gierlik, M; Gorska, M; Grawe, H; Hellstrom, M; Janas, Z; Jokinen, A; Karny, M; Kirchner, R; La Commara, M; Langanke, K; Martinez-Pinedo, G; Mayet, P; Nieminen, A; Nowacki, F; Penttila, H; Plochocki, A; Rejmund, M; Roeckl, E; Schlegel, C; Schmidt, K; Schwengner, R; Sawicka, M


    The proton-rich isotope Cu-56 was produced at the GSI On-Line Mass Separator by means of the Si-28(S-32, p3n) fusion-evaporation reaction. Its beta -decay properties were studied by detecting beta -delayed gamma rays and protons. A half-Life of 93 +/- 3 ms was determined for Cu-56. Compared to the p

  2. Reward Motivation Enhances Task Coding in Frontoparietal Cortex. (United States)

    Etzel, Joset A; Cole, Michael W; Zacks, Jeffrey M; Kay, Kendrick N; Braver, Todd S


    Reward motivation often enhances task performance, but the neural mechanisms underlying such cognitive enhancement remain unclear. Here, we used a multivariate pattern analysis (MVPA) approach to test the hypothesis that motivation-related enhancement of cognitive control results from improved encoding and representation of task set information. Participants underwent two fMRI sessions of cued task switching, the first under baseline conditions, and the second with randomly intermixed reward incentive and no-incentive trials. Information about the upcoming task could be successfully decoded from cue-related activation patterns in a set of frontoparietal regions typically associated with task control. More critically, MVPA classifiers trained on the baseline session had significantly higher decoding accuracy on incentive than non-incentive trials, with decoding improvement mediating reward-related enhancement of behavioral performance. These results strongly support the hypothesis that reward motivation enhances cognitive control, by improving the discriminability of task-relevant information coded and maintained in frontoparietal brain regions. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail:

  3. Novice supervisors' tasks and training

    DEFF Research Database (Denmark)

    Nielsen, Jan; Jacobsen, Claus Haugaard; Mathiesen, Birgit Bork


    were confronted with complicated jobs, e.g., group, internal and interdisciplinary supervision, but were not prepared, i.e. trained, prior to these tasks. These findings imply that more training is needed for novice supervisors. Preferably, this training should be introduced before, or at least...... parallel to, the first supervisor tasks, preparing the novice supervisors for the often complicated tasks they are meeting....

  4. Principles of Communicative Task Design. (United States)

    Nunan, David

    The use of the learning task as a basic planning and instructional tool for communicative second language instruction is discussed, and considerations and procedures for designing such tasks are outlined. A task is defined as a piece of classroom work that involves learners in comprehending, manipulating, producing, or interacting in the target…

  5. TASK: Let's Have a Party! (United States)

    Rees, James


    In this article, the author describes a creative way to demystify contemporary art for students. TASK is artist Oliver Herring's creation, where participants actively interpret instructions found on little pieces of paper--what he calls "tasks." An art classroom has all the key ingredients for a TASK event: (1) people; (2) materials; (3) space;…

  6. TASK: Let's Have a Party! (United States)

    Rees, James


    In this article, the author describes a creative way to demystify contemporary art for students. TASK is artist Oliver Herring's creation, where participants actively interpret instructions found on little pieces of paper--what he calls "tasks." An art classroom has all the key ingredients for a TASK event: (1) people; (2) materials; (3) space;…

  7. GMI in FeCuNbSiB/Cu multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Correa, M.A. [Departamento de Fisica, CCNE, UFSM, 97105-900, Santa Maria, RS (Brazil)]. E-mail:; Viegas, A.D.C. [Departamento de Fisica, CCNE, UFSM, 97105-900, Santa Maria, RS (Brazil); Silva, R.B. da [Departamento de Fisica, CCNE, UFSM, 97105-900, Santa Maria, RS (Brazil); Andrade, A.M.H. de [Departamento de Fisica, CCNE, UFSM, 97105-900, Santa Maria, RS (Brazil); Sommer, R.L. [Centro Brasileiro de Pesquisas Fisicas, 22290-180, Rio de Janeiro, RJ (Brazil)


    Very high magnetoimpedance (MI) measured at frequencies up to 1.8 GHz in single and multilayered thin films with composition Fe{sub 73.5}Cu{sub 1}Nb{sub 3}Si{sub 13.5}B{sub 9} and (Fe{sub 73.5}Cu{sub 1}Nb{sub 3}Si{sub 13.5}B{sub 9}+Cu) are reported. The magnetic properties of both systems are also compared. MI ratio as high as 300% for the multilayered samples were obtained.

  8. Cu-Cr Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Need, Ryan F. [Los Alamos National Laboratory


    Cu-Cr alloys are part of a class of face-centered cubic (FCC)-body-centered cubic (BCC) composites that includes similar alloys, such as Cu-Nb and Cu-Ta. When heavily deformed, these FCC-BCC materials create 'in situ' composites with a characteristic structure-nanoscale BCC filaments in a ductile FCC matrix. The strength of these composites is vastly greater than predicted by the rule of mixtures, and has been shown to be inversely proportional to the filament spacing. Lower raw materials costs suggest that Cu-Cr alloys may offer more economical solution to high-strength, high-conductivity wire than either their Nb or Ta counterparts. However, Cr is also more brittle and soluble in Cu than Nb or Ta. These qualities necessitate thermal treatments to remove solute atoms from the Cu matrix, improve conductivity, and maintain the ductility of the Cr filaments. Through the use of different thermomechanical processing routes or the addition of select dopants, alloys with strength in excess of 1 GPa at 70% IACS have been achieved. To date, previous research on Cu-Cr alloys has focused on a relatively small number of alloy compositions and processing methods while the effects of dopants and ageing treatments have only been studied independently. Consequently, there remains considerable opportunity for the development and optimization of these alloys as a leading high-strength, high-conductivity material.

  9. Cu-ZSM-5, Cu-ZSM-11, and Cu-ZSM-12 Catalysts for Direct NO Decomposition

    DEFF Research Database (Denmark)

    Kustova, Marina; Kustov, Arkadii; Christiansen, Sofie E.


    Cu-ZSM-5 has for many years been recognized as a unique catalyst for direct NO decomposition. Here, it is discovered that both Cu-ZSM-11 and Cu-ZSM-12 are about twice as active as Cu-ZSM-5. This difference is attributed to the active sites located almost exclusively in the straight zeolite pores...

  10. Possible mechanism of superconductivity in CuO-Cu interface

    CERN Document Server

    Amelin, I I


    The CuO two-dimensional lattice consisting of the Cu sup 2 sup + and O sup 1 sup - ions which form the narrow partially filled two-dimensional zone is apparently formed in the CuO-Cu interface on the copper oxide surface. In this case formation of local electron pairs (LEP) is possible in the plane oxygen subsystem due to the Shubin-Vonsovskii conditions. In this approximation rough evaluation of the LEP formation temperature results in the T* approx 10 sup 4 K value. The temperature of the initial Bose-Einstein condensation by the concentration in the interface layer n approx 1.6 x 10 sup 2 sup 0 cm sup - sup 3 and the carriers effective mass m* approx m sub e may have the value of T sub c approx 1000 K. The obtained evaluation of the T sub c temperature corresponds by the values order to the experimental value

  11. The influence of dietary Cu and diabetes on tissue sup 67 Cu retention kinetics in rats

    Energy Technology Data Exchange (ETDEWEB)

    Uriu-Hare, J.Y.; Rucker, R.B.; Keen, C.L. (Univ. of California, Davis (United States))


    Compared to controls, diabetes results in higher plasma, liver and kidney Cu concentrations. Since alterations in Cu metabolism may be associated with diabetic pathology, the authors investigated how Cu metabolism is affected by diabetes and dietary Cu intake. Nondiabetic and STZ diabetic rats were fed Cu suppl. or Cu def. diets for 5 wks. Rats were intubated with 28 {mu}Ci {sup 67}Cu and killed after 8, 16, 24, 32, 64, or 128 h. There were marked effects of both diet and diabetes on {sup 67}Cu metabolism. Independent of diabetes, deficient rats had a higher % of retained {sup 67}Cu, in liver, plasma, RBC, muscle, spleen, brain, lung, uterus, and intestine than adequate Cu rats. Independent of dietary Cu, diabetic rats had a lower % of retained {sup 67}Cu in liver, plasma, RBC, muscle, spleen, lung, bone, pancreas, skin, uterus and heart than controls. Differential effects were noted for kidney; adequate Cu diabetic rats had a higher % of retained {sup 67}Cu than all other groups. Marked effects of both diet and diabetes were evident when tissue Cu turnover was examined. Compared to Cu suppl. rats, Cu def. rats had a slower turnover of {sup 67}Cu, in liver, plasma, intestine, pancreas, eye, brain, muscle, spleen, lung and heart. Diabetic rats had a slower turnover of {sup 67}Cu than nondiabetic rats in liver, plasma, intestine, pancreas, eye, kidney, RBC and uterus. The data imply that a focus on Cu metabolism with regard to cellular Cu trafficking and pathology may be warranted.

  12. A formative evaluation of CU-SeeMe (United States)

    Bibeau, Michael


    CU-SeeMe is a video conferencing software package that was designed and programmed at Cornell University. The program works with the TCP/IP network protocol and allows two or more parties to conduct a real-time video conference with full audio support. In this paper we evaluate CU-SeeMe through the process of Formative Evaluation. We first perform a Critical Review of the software using a subset of the Smith and Mosier Guidelines for Human-Computer Interaction. Next, we empirically review the software interface through a series of benchmark tests that are derived directly from a set of scenarios. The scenarios attempt to model real world situations that might be encountered by an individual in the target user class. Designing benchmark tasks becomes a natural and straightforward process when they are derived from the scenario set. Empirical measures are taken for each task, including completion times and error counts. These measures are accompanied by critical incident analysis 2 7 13 which serves to identify problems with the interface and the cognitive roots of those problems. The critical incidents reported by participants are accompanied by explanations of what caused the problem and why This helps in the process of formulating solutions for observed usability problems. All the testing results are combined in the Appendix in an illustrated partial redesign of the CU-SeeMe Interface.

  13. Task Prioritization in Dual-Tasking: Instructions versus Preferences (United States)

    Jansen, Reinier J.; van Egmond, René; de Ridder, Huib


    The role of task prioritization in performance tradeoffs during multi-tasking has received widespread attention. However, little is known on whether people have preferences regarding tasks, and if so, whether these preferences conflict with priority instructions. Three experiments were conducted with a high-speed driving game and an auditory memory task. In Experiment 1, participants did not receive priority instructions. Participants performed different sequences of single-task and dual-task conditions. Task performance was evaluated according to participants’ retrospective accounts on preferences. These preferences were reformulated as priority instructions in Experiments 2 and 3. The results showed that people differ in their preferences regarding task prioritization in an experimental setting, which can be overruled by priority instructions, but only after increased dual-task exposure. Additional measures of mental effort showed that performance tradeoffs had an impact on mental effort. The interpretation of these findings was used to explore an extension of Threaded Cognition Theory with Hockey’s Compensatory Control Model. PMID:27391779

  14. Effect of simulator motion cuing on steering control performance : Driving simulator study

    NARCIS (Netherlands)

    Feenstra, P.J.; Horst, A.R.A. van der; Grácio, B.J.C.; Wentink, M.


    The goal of the present study was to explore how simulator motion cuing affects the driver's control performance of a car. Steering behavior was used as a measure of control performance. The experimental task was a slalom maneuver in which the velocity of the car was limited to 70 km/h. Subjective

  15. Uncovering the Problem-Solving Process: Cued Retrospective Reporting Versus Concurrent and Retrospective Reporting (United States)

    van Gog, Tamara; Paas, Fred; Merrienboer, Jeroen J. G.; Witte, Puk


    This study investigated the amounts of problem-solving process information ("action," "why," "how," and "metacognitive") elicited by means of concurrent, retrospective, and cued retrospective reporting. In a within-participants design, 26 participants completed electrical circuit troubleshooting tasks under different reporting conditions. The…

  16. Cu metabolism in the liver. (United States)

    McArdle, H J; Bingham, M J; Summer, K; Ong, T J


    This paper has, given some idea of our concepts of the processes involved in the transport of Cu across cell membranes in the liver, which we have summarised in Fig 1. Cu(II)His2 is reduced to Cu(I). This is transported across the membrane, re-oxidised, either before or after binding to glutathione (Freedman et al., 1989) or HAH1 (Klomp et al., 1997), binds to SAHH, and donates Cu(II) to the ATPase. It is very interesting that cells which are very diverse from an evolutionary point of view still use very similar methods to handle the metal. Whether regulation of transport is also the sam remains to be seen. We would guess that, although there will be strong similarities, there will also be very significant differences, reflecting the different environments seen by different tissues in mammalian cells and given the different requirements of the tissues.

  17. Cu influence on hens weight (United States)

    Afonina, I. A.; Kleptsyna, E. S.; Petukhov, V. L.; Patrashkov, S. A.


    Copper plays an important part in living being bodies. But, both high and low Cu levels may cause human and animal diseases. Some East Siberia areas are characterized by Cu pollution [1]. 5 group of hens were formed: 1 - control, 2-5 - experimental. For a month the hens from experimental groups were drunk with water where Cu content was 5, 10, 20 and 30 times higher than the upper limits (UL). Group 1 - 3 hens' weight was almost the same during the experiment. Weight decrease (from 2020 to 1656 g) was detected in group 4 (20 UL) for the first half a month. All the hens of group 4 except for 3 hens were died for the last 2 weeks. In group 5 (30 UL) all the hens died after 2 ... 14 days. Thus, high Cu concentrations (20 ... 30 UL) cause hens' weight reduction of and their death.

  18. Effect of grain orientations of Cu seed layers on the growth of -oriented nanotwinned Cu

    National Research Council Canada - National Science Library

    Liu, Chien-Min; Lin, Han-Wen; Lu, Chia-Ling; Chen, Chih


    .... It is found that densely-packed nanotwinned Cu (nt-Cu) can be grown by pulsed electroplating on the strong -oriented Cu seed layer without a randomly-oriented transition layer between the nt-Cu and the Cu seed layer...

  19. Peri-event cross-correlation over time for analysis of interactions in neuronal firing. (United States)

    Paiva, António R C; Park, Il; Sanchez, Justin C; Príncipe, José C


    Several methods have been described in the literature to verify the presence of couplings between neurons in the brain. In this paper we introduce the peri-event cross-correlation over time (PECCOT) to describe the interaction among the two neurons as a function of the event onset. Instead of averaging over time, the PECCOT averages the cross-correlation over instances of the event. As a consequence, the PECCOT is able to characterize with high temporal resolution the interactions over time among neurons. To illustrate the method, the PECCOT is applied to a simulated dataset and for analysis of synchrony in recordings of a rat performing a go/no go behavioral lever press task. We verify the presence of synchrony before the lever press time and its suppression afterwards.

  20. The Cu II Spectrum

    Directory of Open Access Journals (Sweden)

    Alexander Kramida


    Full Text Available New wavelength measurements in the vacuum ultraviolet (VUV, ultraviolet and visible spectral regions have been combined with available literature data to refine and extend the description of the spectrum of singly ionized copper (Cu II. In the VUV region, we measured 401 lines using a concave grating spectrograph and photographic plates. In the UV and visible regions, we measured 276 lines using a Fourier-transform spectrometer. These new measurements were combined with previously unpublished data from the thesis of Ross, with accurate VUV grating measurements of Kaufman and Ward, and with less accurate older measurements of Shenstone to construct a comprehensive list of ≈2440 observed lines, from which we derived a revised set of 379 optimized energy levels, complemented with 89 additional levels obtained using series formulas. Among the 379 experimental levels, 29 are new. Intensities of all lines observed in different experiments have been reduced to the same uniform scale by using newly calculated transition probabilities (A-values. We combined our calculations with published measured and calculated A-values to provide a set of 555 critically evaluated transition probabilities with estimated uncertainties, 162 of which are less than 20%.

  1. The impact of fluency on explicit memory tasks in amnesia. (United States)

    Hayes, Scott M; Verfaellie, Mieke


    Abstract Distinguishing implicit and explicit memory and delineating their relationship has haunted memory researchers for decades, and Voss et al. provide an impressive overview of their work examining these issues. We briefly comment on the following: (1) There is evidence indicating that implicit memory impacts cued recall, in addition to recognition; (2) Fluency can manifest as priming in implicit memory or it can be experienced as familiarity (in association with attribution processes) in recognition tasks; and (3) The impact of fluency on accuracy of "guess" responses during recognition memory in normal subjects is reminiscent of similar effects on recognition in amnesia.

  2. Task Analyses for Difficult-to-Assess Collective Tasks (United States)


    Counterintelligence and Human Intelligence Analysis and Production (34-4-1305) • Conduct Counterintelligence and Human Intelligence Analysis (34-4...Research Product 2014-05 Task Analyses for Difficult-to-Assess Collective Tasks Jonathan J. Bryson Rachel D. Barney...Christina K. Curnow Trevor M. Conrad Arnold L. Leonard Heidi Keller-Glaze ICF International Jennifer S. Tucker Christopher L. Vowels

  3. The effect of dietary Cu and diabetes on indices of Cu nutriture in the rat

    Energy Technology Data Exchange (ETDEWEB)

    Rucker, R.B.; Uriu-Hare, J.Y.; Tinker, D.; Keen, C.L. (Univ. of California, Davis (United States))


    The uptake-retention of 67Cu is affected by dietary Cu and diabetes. Consequently, the functional activities of select enzymes and tissue Cu status were assessed. STZ-diabetic and control rats were fed Cu suppl. or def. diets. Rats were gavaged with 28 {mu}Ci 67Cu, and killed 8, 16, 24, 32, 64, or 128 h later. Diabetic rats were hyperphagic, hyperglycemic and hypoinsulinemic; with no effect of diet. Plasma ceruloplasmin activity (Cp) was lower in Cu def. rats; diabetic rats tended to have higher Cp than controls. Cu def. rats had low Cu levels in liver, kidney and plasma. Cu suppl. diabetic rats had higher liver and kidney Cu compared to Cu def. diabetic rats. Gel chromatography of liver showed that with time, there was a transfer of 67Cu from low to higher MW ligands. In nondiabetic rats, more 67Cu was associated with the higher MW ligands. The converse was observed for diabetic rats. There was no effect of diabetes on liver 67Cu localization. Diabetic rats had higher metallothionein (MT) concentrations in liver and kidney compared to controls Cu deficiency lowered MT values in both diabetic and control rats. CuZn SOD Cu activity was lowered with Cu def. and diabetes, while Mn SOD activity was similar among groups. Plasma lipid peroxide levels were lower in diabetic rats than controls. The results show that Cu metabolism is affected in diabetes, and the changes are functionally significant.

  4. Predictability of Operant Behavior of Rats by Prefrontal Multiple Unit Activities (United States)

    Fujiwara, Sei-Etsu; Akema, Tatsuo; Izaki, Yoshinori

    To investigate the possibility of a brain computer interface (BCI) constructed using activities of the prefrontal cortex (PFC), we analyzed PFC multiple unit activities (MUAs) during a delayed reinforcement (DRF) lever press task in rats. In the DRF task, each trial consisted of two lever press responses (R1, R2): R1 as the trial initiation, R2 as a pre-conditioned response to a stimulus (buzzer) for a reward. Between R1 and the buzzer, rats were required to inhibit the lever press (waiting phase). The trial was evaluated as incorrect if rats pressed the lever during the waiting phase. Results show that the mean firing rate (MFR) was significantly lower around the time of R1 compared with the pre-trial time in correct trials, although no significant changes were found in incorrect trials. From a neuroengineering perspective, the MFR of each single trial was calculated. Most correct trials showed decreasing MFR around the time of R1. The PFC MUA might be useful for BCI.

  5. Phonon spectral densities of Cu surfaces: Application to Cu(211) (United States)

    Mărinică, M.-C.; Raşeev, G.; Smirnov, K. S.


    Power phonon spectra of vicinal stepped surfaces of Cu(211) have been calculated using a molecular dynamics method combined with a semiempirical potential. The potential is based on an analytic form of inverse powers proposed by Finnis and Sinclair with the parametrization of Sutton and Chen. One of the four independent parameters of the potential was rescaled to reproduce the bulk phonon spectrum of Cu while retaining other properties of the bulk Cu close to the experimental values. Using this potential, we calculated the power surface phonon spectra, projection of the spectra at the high-symmetry points of surface Brillouin zone (SBZ), and the mean square displacements (MSD's) of atoms of the Cu(211) surface. The calculated projected phonon spectra at Γ¯ and at two new SBZ points (at X¯ and Y¯) compare favorably with experiment and theory when available. The MSD of the Cu(211) surface is also well reproduced and its temperature dependence shows that anharmonicity of the atomic motion becomes important above 200 K.

  6. Caffeine improves anticipatory processes in task switching

    NARCIS (Netherlands)

    Tieges, Zoe; Snel, Jan; Kok, Albert; Wijnen, Jasper G.; Lorist, Monicque M.; Ridderinkhof, K. Richard

    We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials

  7. Caffeine improves anticipatory processes in task switching

    NARCIS (Netherlands)

    Tieges, Zoe; Snel, Jan; Kok, Albert; Wijnen, Jasper G.; Lorist, Monicque M.; Ridderinkhof, K. Richard


    We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials (e

  8. Decision paths in complex tasks (United States)

    Galanter, Eugene


    Complex real world action and its prediction and control has escaped analysis by the classical methods of psychological research. The reason is that psychologists have no procedures to parse complex tasks into their constituents. Where such a division can be made, based say on expert judgment, there is no natural scale to measure the positive or negative values of the components. Even if we could assign numbers to task parts, we lack rules i.e., a theory, to combine them into a total task representation. We compare here two plausible theories for the amalgamation of the value of task components. Both of these theories require a numerical representation of motivation, for motivation is the primary variable that guides choice and action in well-learned tasks. We address this problem of motivational quantification and performance prediction by developing psychophysical scales of the desireability or aversiveness of task components based on utility scaling methods (Galanter 1990). We modify methods used originally to scale sensory magnitudes (Stevens and Galanter 1957), and that have been applied recently to the measure of task 'workload' by Gopher and Braune (1984). Our modification uses utility comparison scaling techniques which avoid the unnecessary assumptions made by Gopher and Braune. Formula for the utility of complex tasks based on the theoretical models are used to predict decision and choice of alternate paths to the same goal.

  9. Putting Mathematical Tasks into Context (United States)

    Nagle, Courtney R.; Styers, Jodie L.


    Although many factors affect students' mathematical activity during a lesson, the teacher's selection and implementation of tasks is arguably the most influential in determining the level of student engagement. Mathematical tasks are intended to focus students' attention on a particular mathematical concept and it is the careful developing and…

  10. Human-System task integration

    NARCIS (Netherlands)

    Schraagen, J.M.C.


    The Dutch Ministry of Defence research programme Human-System Task Integration aims at acquiring knowledge for the optimal cooperation between human and computer, under the following constraints: freedom of choice in decisions to automate and multiple, dynamic task distributions. This paper describe

  11. Designing for dynamic task allocation

    NARCIS (Netherlands)

    Dongen, C.J.G. van; Maanen, P.P. van


    Future platforms are envisioned in which human-machine teams are able to share and trade tasks as demands in situations change. It seems that human-machine coordination has not received the attention it deserves by past and present approaches to task allocation. In this paper a simple way to make co

  12. Creativity, Overinclusion, and Everyday Tasks (United States)

    Ottemiller, Dylan D.; Elliott, Colette Seter; Giovannetti, Tania


    This study examined relations between creative thinking and performance on routine, everyday tasks. Results were considered in light of past research on the putative relation between creativity and schizophrenia/psychotic thinking. Thirty healthy undergraduates completed the Alternative Uses Task, a measure of divergent thinking, and the 2 × 3…

  13. Task modeling for collaborative authoring

    NARCIS (Netherlands)

    Veer, van der Gerrit; Kulyk, Olga; Vyas, Dhaval; Kubbe, Onno; Ebert, Achim; Dittmar, A.; Forbrig, P.


    Motivation –Task analysis for designing modern collaborative work needs a more fine grained approach. Especially in a complex task domain, like collaborative scientific authoring, when there is a single overall goal that can only be accomplished only by collaboration between multiple roles, each req

  14. EFFORTS Sub-task report on task 4.1: Experimental Techniques

    DEFF Research Database (Denmark)

    Andreasen, Jan Lasson; Bay, Niels


    Task 4.1 is a sub-task of task 4: Physical modelling validation. In sub-task 4.1 the existing experimental techniques has been conditioned to the tasks ahead in physical modelling.......Task 4.1 is a sub-task of task 4: Physical modelling validation. In sub-task 4.1 the existing experimental techniques has been conditioned to the tasks ahead in physical modelling....

  15. Impaired dual tasking in Parkinson's disease is associated with reduced focusing of cortico-striatal activity. (United States)

    Nieuwhof, Freek; Bloem, Bastiaan R; Reelick, Miriam F; Aarts, Esther; Maidan, Inbal; Mirelman, Anat; Hausdorff, Jeffrey M; Toni, Ivan; Helmich, Rick C


    Impaired dual tasking, namely the inability to concurrently perform a cognitive and a motor task (e.g. 'stops walking while talking'), is a largely unexplained and frequent symptom of Parkinson's disease. Here we consider two circuit-level accounts of how striatal dopamine depletion might lead to impaired dual tasking in patients with Parkinson's disease. First, the loss of segregation between striatal territories induced by dopamine depletion may lead to dysfunctional overlaps between the motor and cognitive processes usually implemented in parallel cortico-striatal circuits. Second, the known dorso-posterior to ventro-anterior gradient of dopamine depletion in patients with Parkinson's disease may cause a funnelling of motor and cognitive processes into the relatively spared ventro-anterior putamen, causing a neural bottleneck. Using functional magnetic resonance imaging, we measured brain activity in 19 patients with Parkinson's disease and 26 control subjects during performance of a motor task (auditory-cued ankle movements), a cognitive task (implementing a switch-stay rule), and both tasks simultaneously (dual task). The distribution of task-related activity respected the known segregation between motor and cognitive territories of the putamen in both groups, with motor-related responses in the dorso-posterior putamen and task switch-related responses in the ventro-anterior putamen. During dual task performance, patients made more motor and cognitive errors than control subjects. They recruited a striatal territory (ventro-posterior putamen) not engaged during either the cognitive or the motor task, nor used by controls. Relatively higher ventro-posterior putamen activity in controls was associated with worse dual task performance. These observations suggest that dual task impairments in Parkinson's disease are related to reduced spatial focusing of striatal activity. This pattern of striatal activity may be explained by a loss of functional segregation

  16. Attentional costs of visually guided walking: effects of age, executive function and stepping-task demands. (United States)

    Mazaheri, Masood; Roerdink, Melvyn; Bood, Robert Jan; Duysens, Jacques; Beek, Peter J; Peper, C Lieke E


    During walking, attention needs to be flexibly allocated to deal with varying environmental constraints. This ability may be affected by aging and lower overall executive function. The present study examined the influence of aging and executive function on the attentional costs of visually guided walking under different task demands. Three groups, young adults (n=15) and elderly adults with higher (n=16) and lower (n=10) executive function, walked on a treadmill in three conditions: uncued walking and walking with regular and irregular patterns of visual stepping targets projected onto the belt. Attentional costs were assessed using a secondary probe reaction time task and corrected by subtracting baseline single-task reaction time, yielding an estimate of the additional attentional costs of each walking condition. We found that uncued walking was more attentionally demanding for elderly than for young participants. In young participants, the attentional costs increased significantly from uncued to regularly cued to irregularly cued walking, whereas for the higher executive function group, attentional costs only increased significantly from regularly cued to irregularly cued walking. For the group with lower executive function, no significant differences were observed. The observed decreased flexibility of elderly, especially those with lower executive function, to allocate additional attentional resources to more challenging walking conditions may be attributed to the already increased attentional costs of uncued walking, presumably required for visuomotor and/or balance control of walking.

  17. CuZn Alloy- Based Electrocatalyst for CO2 Reduction

    KAUST Repository

    Alazmi, Amira


    ABSTRACT CuZn Alloy- Based Electrocatalyst for CO2 Reduction Amira Alazmi Carbon dioxide (CO2) is one of the major greenhouse gases and its emission is a significant threat to global economy and sustainability. Efficient CO2 conversion leads to utilization of CO2 as a carbon feedstock, but activating the most stable carbon-based molecule, CO2, is a challenging task. Electrochemical conversion of CO2 is considered to be the beneficial approach to generate carbon-containing fuels directly from CO2, especially when the electronic energy is derived from renewable energies, such as solar, wind, geo-thermal and tidal. To achieve this goal, the development of an efficient electrocatalyst for CO2 reduction is essential. In this thesis, studies on CuZn alloys with heat treatments at different temperatures have been evaluated as electrocatalysts for CO2 reduction. It was found that the catalytic activity of these electrodes was strongly dependent on the thermal oxidation temperature before their use for electrochemical measurements. The polycrystalline CuZn electrode without thermal treatment shows the Faradaic efficiency for CO formation of only 30% at applied potential ~−1.0 V vs. RHE with current density of ~−2.55 mA cm−2. In contrast, the reduction of oxide-based CuZn alloy electrode exhibits 65% Faradaic efficiency for CO at lower applied potential about −1.0 V vs. RHE with current density of −2.55 mA cm−2. Furthermore, stable activity was achieved over several hours of the reduction reaction at the modified electrodes. Based on electrokinetic studies, this improvement could be attributed to further stabilization of the CO2•− on the oxide-based Cu-Zn alloy surface.

  18. Speciation of Cu in MSWI bottom ash and its relation to Cu leaching

    Energy Technology Data Exchange (ETDEWEB)

    Arickx, S. [Department of Chemical Engineering, Katholieke Universiteit Leuven, W. de Croylaan 46, B-3001 Leuven (Belgium)], E-mail:; Gerven, T. van [Department of Chemical Engineering, Katholieke Universiteit Leuven, W. de Croylaan 46, B-3001 Leuven (Belgium); Boydens, E.; L' Hoest, P.; Blanpain, B. [Department of Metallurgy and Materials Engineering, Katholieke Universiteit Leuven, Kasteelpark Arenberg 44, B-3001 Leuven (Belgium); Vandecasteele, C. [Department of Chemical Engineering, Katholieke Universiteit Leuven, W. de Croylaan 46, B-3001 Leuven (Belgium)], E-mail:


    In Flanders, recycling of bottom ash is mainly inhibited by the high leaching of Cu. Although it has been proved that dissolved organic C plays a major role in the Cu leaching, the possible role of inorganic Cu mineral speciation has never been experimentally examined. In this study the speciation of Cu is investigated using a combination of optical microscopy and electron microprobe -WDX/EDX. Several Cu species were determined. Metallic Cu (with or without an oxide shell), CuO and Cu{sub 2}O were the most abundant. These particles were most likely present in wire-like structures. Copper also occurred as alloy (brass, bronze, zamak), and was found frequently together with typical elements such as Ca, Cl and S. Finally, small metallic Cu particles seemed to be trapped in or precipitated on oxides and silicates. Based on this Cu speciation study, pure Cu minerals were selected and leached as a function of time. The solubility after equilibrium of all studied Cu minerals never exceeded 20 {mu}g/L (which equals 10% of the total Cu leaching). The effect of heating (2 h at 400 deg. C) on the speciation of Cu was investigated using the same combination of techniques. Results show that metallic Cu seemed to be converted to Cu oxide (mostly CuO) and that the particles were more porous after heating. These conclusions were verified by XRD analysis of the heated pure Cu minerals. After heating, the Cu minerals were also leached as a function of time, to study the impact on Cu leaching. Results indicate that their leaching had slightly increased in comparison with the non-heated Cu minerals. However, the major decrease in Cu leaching in heated bottom ash, more than neutralizes this effect and thus can be attributed to the destruction of organic matter and not to the (small) change in Cu speciation.

  19. Divergent Perceptions of Telecollaborative Language Learning Tasks: Task-as-Workplan vs. Task-as-Process

    National Research Council Canada - National Science Library

    Dooly, Melinda


    ... place. The task design and its implementation are key elements for efficient language learning to develop--a carefully designed task or activity that requires off- and online co-construction of knowledge not only provides opportunities for target language practice, it also helps integrate language use as the means for shared knowledge-build...

  20. Microfluidic reactor synthesis and photocatalytic behavior of Cu@Cu{sub 2}O nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Lei, E-mail: [National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Mechanical Engineering, University of Washington, Seattle, WA 98195 (United States); Srinivasakannan, C. [Chemical Engineering Program, The Petroleum Institute, PO Box 253, Abu Dhabi (United Arab Emirates); Peng, Jinhui, E-mail: [National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Yan, Mi [Faculty of Mathematical and Physical Sciences, University College London, London WC1E 6BT (United Kingdom); Zhang, Di [Mechanical Engineering, University of Washington, Seattle, WA 98195 (United States); Zhang, Libo [National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China)


    Highlights: • The Cu@Cu{sub 2}O nanocomposites were synthesized in microfluidic reactor followed by oxidation process. • The Cu@Cu{sub 2}O composite particle is on nanoscale exhibiting an open bicontinuous structure. • The amount of Cu{sub 2}O can be controlled by varying drying temperature. • The binary Cu@Cu{sub 2}O–H{sub 2}O{sub 2} systems exhibit an excellent photocatalyst for degradation methylene blue under UV irradiation. - Abstract: The Cu@Cu{sub 2}O nanocomposites were synthesized by solution-phase synthesis of Cu nanoparticles in microfluidic reactor at room temperature, followed by controlling the oxidation process. The size, morphology, elemental compositions, and the chemical composition on the surface of Cu@Cu{sub 2}O nanocomposite were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Experimental results demonstrated that the surface of the Cu nanoparticles was oxidized to Cu{sub 2}O which serves as the shell of nanoparticle. The amount of Cu{sub 2}O can be controlled by varying the drying temperature. Additionally the binary Cu@Cu{sub 2}O nanocomposite along with H{sub 2}O{sub 2} exhibited its potential as an excellent photocatalyst for degradation of methylene blue (MB) under UV irradiation.

  1. Visual Search and Attention in Blue Jays (Cyanocitta cristata): Associative Cuing and Sequential Priming (United States)

    Goto, Kazuhiro; Bond, Alan B.; Burks, Marianna; Kamil, Alan C.


    Visual search for complex natural targets requires focal attention, either cued by predictive stimulus associations or primed by a representation of the most recently detected target. Since both processes can focus visual attention, cuing and priming were compared in an operant search task to evaluate their relative impacts on performance and to determine the nature of their interaction in combined treatments. Blue jays were trained to search for pairs of alternative targets among distractors. Informative or ambiguous color cues were provided prior to each trial, and targets were presented either in homogeneous blocked sequences or in constrained random order. Initial task acquisition was facilitated by priming in general, but was significantly retarded when targets were both cued and primed, indicating that the two processes interfered with each other during training. At asymptote, attentional effects were manifested mainly in inhibition, increasing latency in miscued trials and decreasing accuracy on primed trials following an unexpected target switch. A combination of cuing and priming was found to interfere with performance in such unexpected trials, apparently a result of the limited capacity of working memory. Because the ecological factors that promote priming and cuing are rather disparate, it is not clear whether they ever jointly and simultaneously contribute to natural predatory search. PMID:24893217

  2. Ear advantage and attention: an ERP study of auditory cued attention. (United States)

    Ofek, E; Pratt, H


    The neurophysiological manifestations of left ear advantage to tonal stimuli and its interaction with attention have rarely been studied. Cued attention is a behavioral paradigm to assess the behavioral benefits and costs of allocating attention. In this task a cue predicts the location of a subsequent target to which the subject responds. In most cases the cue correctly predicts the target (valid cues) but at times it does not (invalid cues). Cued attention is a spatial paradigm with stimuli presented to either side. The objectives of this study were: (1) to find the neurophysiological correlates of the ear advantage phenomenon and (2) to assess the interaction of the stimulated side (right vs. left ear advantage) with attention, in a cued attention task. Significant effects on event-related potentials (ERPs) in the cued attention task indicated left ear and right hemisphere advantage. Effects were mostly confined to the right hemisphere. The results indicate interactions among left ear advantage, attention and dominant hand utilization. Ear advantage and attention may involve the same neural mechanisms. In spite of the left ear advantage effect on ERP components, hand dominance determines the final behavioral results (reaction times).

  3. Facile Synthesis of Colored and Conducting CuSCN Composite Coated with CuS Nanoparticles (United States)

    Premalal, E. V. A.; Kannangara, Yasun Y.; Ratnayake, S. P.; Nalin de Silva, K. M.


    Conductivity-tunable, different colored CuS nanoparticle-coated CuSCN composites were synthesized in a single pot using a mixture of copper sulfate and sodium thiosulfate in the presence of triethyl amine hydrothiocyanate (THT) at the ambient condition. When these reagents are mixed in 1:1:1 molar ratio, white-gray-colored CuSCN was produced. In the absence of THT, microsized dark blue-colored CuS particles were produced. However, when THT is present in the solution mixture by different amounts, colored conducting CuS nanoparticle-coated CuSCN composite was produced. CuS nanoparticles are not deposited on CuSCN soon after mixing these regents, but it takes nearly overnight to see the color change (CuS production) in the white CuSCN dispersed mixture. TEM analysis shows that composite consists of hexagonal CuS nanoparticles in the range of 3-10 nm in size. It is interesting to note that CuS-coated CuSCN possesses higher conductivity than neat CuS or CuSCN. Moreover, strong IR absorption was observed for CuS-coated CuSCN composite compared to neat CuS (absence of THT) or CuSCN. Lowest resistivity of 0.05 Ω cm was observed for annealed (250 °C) CuS-coated CuSCN particles (adding 10 ml of THT) under nitrogen atmosphere. Also, this simple method could be extended to be used in the synthesis of CuS-coated composites on the other nanomaterials such as metal oxides, polymers, and metal nanoparticles.

  4. Discrepancy of neural response between exogenous and endogenous task switching: an event-related potentials study. (United States)

    Miyajima, Maki; Toyomaki, Atsuhito; Hashimoto, Naoki; Kusumi, Ichiro; Murohashi, Harumitsu; Koyama, Tsukasa


    Task switching is a well-known cognitive paradigm to explore task-set reconfiguration processes such as rule shifting. In particular, endogenous task switching is thought to differ qualitatively from stimulus-triggered exogenous task switching. However, no previous study has examined the neural substrate of endogenous task switching. The purpose of the present study is to explore the differences between event-related potential responses to exogenous and endogenous rule switching at cue stimulus. We modified two patterns of cued switching tasks: exogenous (bottom-up) rule switching and endogenous (top-down) rule switching. In each task cue stimulus was configured to induce switching or maintaining rule. In exogenous switching tasks, late positive deflection was larger in the switch rule condition than in the maintain rule condition. However, in endogenous switching tasks late positive deflection was unexpectedly larger in the maintain-rule condition than in the switch-rule condition. These results indicate that exogenous rule switching is explicit stimulus-driven processes, whereas endogenous rule switching is implicitly parallel processes independent of external stimulus.

  5. Cu/Cu2O/CuO nanoparticles: Novel synthesis by exploding wire technique and extensive characterization (United States)

    Sahai, Anshuman; Goswami, Navendu; Kaushik, S. D.; Tripathi, Shilpa


    In this article, we explore potential of Exploding Wire Technique (EWT) to synthesize the copper nanoparticles using the copper metal in a plate and wire geometry. Rietveld refinement of X-ray diffraction (XRD) pattern of prepared material indicates presence of mixed phases of copper (Cu) and copper oxide (Cu2O). Agglomerates of copper and copper oxide comprised of ∼20 nm average size nanoparticles observed through high resolution transmission electron microscope (HRTEM) and energy dispersive x-ray (EDX) spectroscopy. Micro-Raman (μR) and Fourier transform infrared (FTIR) spectroscopies of prepared nanoparticles reveal existence of additional minority CuO phase, not determined earlier through XRD and TEM analysis. μR investigations vividly reveal cubic Cu2O and monoclinic CuO phases based on the difference of space group symmetries. In good agreement with μRaman analysis, FTIR stretching modes corresponding to Cu2-O and Cu-O were also distinguished. Investigations of μR and FTIR vibrational modes are in accordance and affirm concurrence of CuO phases besides predominant Cu and Cu2O phase. Quantum confinement effects along with increase of band gaps for direct and indirect optical transitions of Cu/Cu2O/CuO nanoparticles are reflected through UV-vis (UV-vis) spectroscopy. Photoluminescence (PL) spectroscopy spots the electronic levels of each phase and optical transitions processes occurring therein. Iterative X-ray photoelectron spectroscopy (XPS) fitting of core level spectra of Cu (2p3/2) and O (1s), divulges presence of Cu2+ and Cu+ in the lattice with an interesting evidence of O deficiency in the lattice structure and surface adsorption. Magnetic analysis illustrates that the prepared nanomaterial demonstrates ferromagnetic behaviour at room temperature.

  6. Electrochemical deposition and modification of Cu/Co-Cu multilayer

    Energy Technology Data Exchange (ETDEWEB)

    Uhlemann, M.; Gebert, A.; Herrich, M.; Krause, A.; Cziraki, A.; Schultz, L


    Multilayers of Cu/Co-Cu were electrodeposited from a citrate electrolyte on quartz with Au and Si substrates with a Permalloy/Cu seedlayer by means of the potentiostatic double-pulse technique simultaneously controlled by microgravimetric measurements. The influence of a superimposed magnetic field and of annealing conditions on the microstructure has been studied. When an external magnetic field is parallel-orientated toward the electrode, an increase of the Cu deposition rate was observed due to magnetohydrodynamic effects. In contrast, the deposition rate of Co decreases. Microstructural investigations have shown that both a superimposed uniform magnetic field up to 600 mT and an inhomogeneous field of an SmCo permanent magnet change the microstructure and improve the GMR effect. X-ray diffraction measurements revealed that all grains are arranged in the <1 1 1> direction in contrast to layers formed without magnetic field with only 75% of the grains having a (1 1 1) texture. Isothermal heat treatment at different temperatures increases the GMR effect corresponding to an increase of grain size with preferred (1 1 1) orientation.

  7. Task Space Tracking for Manipulators

    Directory of Open Access Journals (Sweden)

    Olav Egeland


    Full Text Available For the purpose of controlling a manipulator in the task space, a linear model with task space position and velocity as state variables can be developed. This is done by means of exact compensation of the state-space model non-linearities using non-linear feedback. In this paper, feedback control for this linear state space model is developed using optimal control theory. Integral action is included to compensate for unmodeled forces and torques. In the resulting control system, the problem of transforming the task space trajectory to the joint space is avoided, and the controller parameters can be chosen to satisfy requirements specified in the task space. Simulation experiments show promising results.

  8. Annual Progress report - General Task

    Energy Technology Data Exchange (ETDEWEB)

    Wesnousky, S.G.


    This report provides a summary of progress for the project {open_quotes}Evaluation of the Geologic Relations and Seismotectonic Stability of the Yucca Mountain Area, Nevada Nuclear Waste Site Investigation (NNWSI).{close_quotes} A similar report was previously provided for the period of 1 October 1991 to 30 September 1992. The report initially covers the activities of the General Task and is followed by sections that describe the progress of the other ongoing tasks.

  9. CuI Thiolate Reactivity with Dioxygen: The Formation of CuII Sulfinate and CuII Sulfonate Species via a CuII Thiolate Intermediate

    NARCIS (Netherlands)

    Ording-Wenker, E.C.M.; Siegler, M.A.M.; Lutz, M.; Bouwman, E.


    CuI(Py2NS) (1) is formed by addition of CuI to a solution of the pyridyl-thiol ligand N-(2-mercaptopropyl)- N,N-bis(2-pyridylmethyl)amine (Py2NSH). Oxidation of complex 1 by air leads to the formation of CuII sulfinate and CuII sulfonate complexes, providing a model for the oxidative degeneration of

  10. Punicalagin Green Functionalized Cu/Cu2O/ZnO/CuO Nanocomposite for Potential Electrochemical Transducer and Catalyst (United States)

    Fuku, X.; Kaviyarasu, K.; Matinise, N.; Maaza, M.


    A novel ternary Punica granatum L-Cu/Cu2O/CuO/ZnO nanocomposite was successfully synthesised via green route. In this work, we demonstrate that the green synthesis of metal oxides is more viable and facile compare to other methods, i.e., physical and chemical routes while presenting a potential electrode for energy applications. The prepared nanocomposite was characterised by both microscopic and spectroscopic techniques. High-resolution scanning electron microscopy (HRSEM) and X-ray diffraction (XRD) techniques revealed different transitional phases with an average nanocrystallite size of 29-20 mm. It was observed that the nanocomposites changed from amorphous-slightly crystalline Cu/Cu2O to polycrystalline Cu/Cu2O/CuO/ZnO at different calcination temperatures (room temperature-RT- 600 °C). The Cu/Cu2O/ZnO/CuO metal oxides proved to be highly crystalline and showed irregularly distributed particles with different sizes. Meanwhile, Fourier transform infrared (FTIR) spectroscopy confirmed the purity while together with ultraviolet-visible (UV-Vis) spectroscopy proved the proposed mechanism of the synthesised nanocomposite. UV-Vis showed improved catalytic activity of the prepared metal oxides, evident by narrow band gap energy. The redox and electrochemical properties of the prepared nanocomposite were achieved by cyclic voltammetry (CV), electrochemical impedance (EIS) and galvanostatic charge-discharge (GCD). The maximum specific capacitance ( C s) was calculated to be 241 F g-1 at 50 mV s-1 for Cu/Cu2O/CuO/ZnO nanoplatelets structured electrode. Moreover, all the CuO nanostructures reveal better power performance, excellent rate as well as long term cycling stability. Such a study will encourages a new design for a wide spectrum of materials for smart electronic device applications.

  11. Compound Cuing in Free Recall (United States)

    Lohnas, Lynn J.; Kahana, Michael J.


    According to the retrieved context theory of episodic memory, the cue for recall of an item is a weighted sum of recently activated cognitive states, including previously recalled and studied items as well as their associations. We show that this theory predicts there should be compound cuing in free recall. Specifically, the temporal contiguity…

  12. Barrier/Cu contact resistivity

    Energy Technology Data Exchange (ETDEWEB)

    Reid, J.S.; Nicolet, M.A. [California Inst. of Tech., Pasadena, CA (United States); Angyal, M.S.; Lilienfeld, D.; Shacham-Diamand, Y. [Cornell Univ., Ithaca, NY (United States); Smith, P.M. [Sandia National Labs., Albuquerque, NM (United States)


    The specific contact resistivity of Cu with ({alpha} + {beta})-Ta, TiN, {alpha}-W, and amorphous-Ta{sub 36}Si{sub 14}N{sub 50} barrier films is measured using a novel four-point-probe approach. Geometrically, the test structures consist of colinear sets of W-plugs to act as current and voltage probes that contact the bottom of a planar Cu/barrier/Cu stack. Underlying Al interconnects link the plugs to the current source and voltmeter. The center-to-center distance of the probes ranges from 3 to 200 {micro}m. Using a relation developed by Vu et al., a contact resistivity of roughly 7 {times} 10{sup {minus}9} {Omega} cm{sup 2} is obtained for all tested barrier/Cu combinations. By reflective-mode small-angle X-ray scattering, the similarity in contact resistivity among the barrier films may be related to interfacial impurities absorbed from the deposition process.

  13. Investigation of agglomerated Cu seed on Cu oxidation after chemical mechanical planarization

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jeng-Yu, E-mail: [Department of Chemical Engineering, Tatung University, Taipei 104, Taiwan (China); Chou, Shu-Wei [Department of Chemical Engineering, Tatung University, Taipei 104, Taiwan (China); Cheng, Min-Yuan [TSMC, No. 8, Li-Hsin Rd. 6, Science-Based Industrial Park, Hsinchu 300-77, Taiwan (China)


    After chemical mechanical planarization (CMP), the reason which caused the formation of Cu-oxide defects at the interface between Cu deposit and TaN barrier layer has been studied. The experimental results of atomic force microscopy, secondary ion mass spectroscopy, X-ray diffraction demonstrated that the agglomeration phenomenon was found on Cu seed in the thickness of only 10 nm, thus resulting in the electrodeposited Cu film with more abundant C impurities at Cu/TaN interface and lower (1 1 1)/(2 0 0) ratio compared to the thick one (30 nm). Therefore it caused the Cu deposit with poor corrosion resistance and then the Cu-oxide defects were easily formed after CMP. As a result, the correlation between Cu-oxide defects at the Cu/TaN interface and the agglomeration on Cu seed layer was proposed herein.


    Institute of Scientific and Technical Information of China (English)

    Y. Q. Ma; C.B. Jiang; H.B. Xu


    Cu-Al-Co and Cu-Al-Zr alloys were explored with Co or Zr additions in Cu-Al alloys for high temperature shape memory alloys. Samples were quenched after homogenized at 850℃ for 48h. It was found that both Cu-Al-Co and Cu-Al-Zr show AlCu3 martensitic phase at room temperature and exhibit martensitic transformation temperatures higher than 200℃, showing the potentials for developing as high temperature shape memory alloys. Thermal cycles were performed by DSC instrument on both Cu-Al-Co and Cu-Al-Zr alloys. The results show that Cu-Al-Co loses its martensitic transformation after five thermal cycles, and Cu-Al-Zr exhibits no martensitic transformation in the second thermal cycle.

  15. Ionic Conductivities of Molten CuI and AgI-CuI Mixtures (United States)

    Tahara, Shuta; Shimakura, Hironori; Ohno, Satoru; Fukami, Takanori


    Ionic conductivities σ for molten CuI and AgI-CuI mixtures were measured in the temperature ranges of approximately 580-800 and 500-850 °C, respectively. The value of σ for molten CuI in the range is smaller than that for molten CuBr and CuCl. σ for molten AgI-CuI mixtures decreases with increasing CuI-concentration. The activation energies Ea for molten AgI-CuI system were determined from the analysis of temperature dependence of σ by using the by Arrhenius type equation. Ea for molten AgI-CuI gradually increase with increasing CuIconcentration.

  16. Differential induction of c-Jun and Fos-like proteins in rat hippocampus and dorsal striatum after training in two water maze tasks. (United States)

    Teather, Lisa A; Packard, Mark G; Smith, Diane E; Ellis-Behnke, Rutledge G; Bazan, Nicolas G


    Research examining the neuroanatomical bases of memory in mammals suggests that the hippocampus and dorsal striatum are parts of independent memory systems that mediate "cognitive" and stimulus-response "habit" memory, respectively. At the molecular level, increasing evidence indicates a role for immediate early gene (IEG) expression in memory formation. The present experiment examined whether acquisition of cognitive and habit memory result in differential patterns of IEG protein product expression in these two brain structures. Adult male Long-Evans rats were trained in either a hippocampal-dependent spatial water maze task, or a dorsal striatal-dependent cued water maze task. Ninety minutes after task acquisition, brains were removed and processed for immunocytochemical procedures, and the number of cells expressing Fos-like immunoreactivity (Fos-like-IR) and c-Jun-IR in sections from the dorsal hippocampus and the dorsal striatum were counted. In the dorsal hippocampus of rats trained in the spatial task, there were significantly more c-Jun-IR pyramidal cells in the CA1 and CA3 regions, relative to rats that had acquired the cued task, yoked controls (free-swim), or naïve (home cage) rats. Relative to rats receiving cued task training and control conditions, increases in Fos-like IR were also observed in the CA1 region of rats trained in the spatial task. In rats that had acquired the cued task, patches of c-Jun-IR were observed in the posteroventral striatum; no such patches were evident in rats trained in the spatial task, yoked-control rats, or naïve rats. The results demonstrate that IEG protein product expression is up-regulated in a task-dependent and brain structure-specific manner shortly after acquisition of cognitive and habit memory tasks.

  17. Effects of a no-go Task 2 on Task 1 performance in dual - tasking: From benefits to costs. (United States)

    Janczyk, Markus; Huestegge, Lynn


    When two tasks are combined in a dual-task experiment, characteristics of Task 2 can influence Task 1 performance, a phenomenon termed the backward crosstalk effect (BCE). Besides instances depending on the (spatial) compatibility of both responses, a particularly interesting example was introduced by Miller (2006): If Task 2 was a no-go task (i.e., one not requiring any action at all), responses were slowed in Task 1. Subsequent work, however, also reported the opposite result-that is, faster Task 1 responses in cases of no-go Task 2 trials. We report three experiments aiming to more precisely identify the conditions under which a no-go Task 2 facilitates or impedes Task 1 performance. The results suggest that an adverse no-go BCE is only observed when the Task 2 response(s) are sufficiently prepared in advance, yielding strong inhibitory control demands for Task 2 that eventually hamper Task 1 processing as well (i.e., inhibitory costs). If this is not the case, encountering a no-go Task 2 trial facilitates Task 1 performance, suggesting that the underlying task representation is reduced to a single - task. These results are discussed in the context of other recent work on BCEs and of recently suggested accounts of the no-go BCE.

  18. Influence of Cu content on the cell biocompatibility of Ti–Cu sintered alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Erlin, E-mail: [Key Lab. for Anisotropy and Texture of Materials, Education Ministry of China, Northeastern University, Shenyang 110819 (China); Jiamusi University, Jiamusi 154007 (China); Zheng, Lanlan [Jiamusi University, Jiamusi 154007 (China); Liu, Jie [Key Lab. for Anisotropy and Texture of Materials, Education Ministry of China, Northeastern University, Shenyang 110819 (China); Dept. of Prosthodontics, The Affiliated Hospital of Medical College, Qingdao University, Qingdao 266003 (China); Bai, Bing [Dept. of Prosthodontics, School of Stomatology, China Medical University, Liaoning Institute of Dental Research, Shenyang 110001 (China); Liu, Cong [Jiamusi University, Jiamusi 154007 (China)


    The cell toxicity and the cell function of Ti–Cu sintered alloys with different Cu contents (2, 5, 10 and 25 wt.%, respectively) have been investigated in comparison with commercial pure titanium in order to assess the influence of Cu content on the cell biocompatibility of the Ti–Cu alloys. The cytotoxicity was studied by examining the MG63 cell response by CCK8 assessment. The cell morphology was evaluated by acridine orange/ethidium bromide (AO/EB) fluorescence and observed under scanning electronic microscopy (SEM). The cell function was monitored by measuring the AKP activity. It has been shown by the AO/EB morphology results that the cell death on both cp-Ti sample and Ti–Cu samples is due to apoptosis rather than necrosis. Although more apoptotic cells were found on the Ti–2Cu and Ti–5Cu samples, no evidence of Cu content dependent manner of apoptosis has been found. SEM observation indicated very good cell adhesion and spread on the cp-Ti sample and the Ti–Cu samples with different Cu contents. CCK8 results displayed that increase in the Cu content in Ti–Cu alloys does not bring about any difference in the cell viability. In addition, AKP test results indicated that no difference in the differentiation of MG63 was found between the cp-Ti and the Ti–Cu samples and among the Ti–Cu samples. All results indicated that Ti–Cu alloys exhibit very good cell biocompatibility and the Cu content up to 25 wt.% in the Ti–Cu alloys has no influence on the cell proliferation and differentiation. - Highlights: • The effect of Cu content on the cell biocompatibility has been investigated. • Cu content shows no influence on the cell proliferation. • Cu content shows no effect on the cell differentiation.

  19. Vacancy defects in epitaxial thin film CuGaSe2 and CuInSe2


    Korhonen, E.; Kuitunen, K.; Tuomisto, Filip; Urbaniak, A.; Igalson, M.; Larsen, J.; Gutay, L; Siebentritt, S; Tomm, Y.


    Epitaxial thin film CuGaSe2 and CuInSe2 samples grown on GaAs substrates with varying [Cu]/[Ga,In] ratios were studied using positron annihilation Doppler-broadening spectroscopy and were compared to bulk crystals. We find both Cu monovacancies and Cu-Se divacancies in CuInSe2, whereas, in CuGaSe2, the only observed vacancy defect is the Cu-Se divacancy. Peer reviewed

  20. Polishing a Data Task: Seeking Better Assessment. (United States)

    Zawojewski, Judith S.


    Shares a teacher's stages of selecting and revising a performance-assessment task focusing on data handling. Discusses selection and revision criteria, examining student work, reflecting on the task, and revising the final task. (MKR)

  1. Task-irrelevant perceptual expertise. (United States)

    Wong, Yetta K; Folstein, Jonathan R; Gauthier, Isabel


    Perceptual learning (PL) and perceptual expertise (PE) are two fields of visual training studies that investigate how practice improves visual performance. However, previous research suggests that PL can be acquired in a task-irrelevant manner while PE cannot and that PL is highly specific to the training objects and conditions while PE generalizes. These differences are difficult to interpret since PL and PE studies tend to differ on multiple dimensions. We designed a training study with novel objects to compare PL and PE while varying only the training task, such that the training objects, visual field, training duration, and type of learning assessment were kept constant. Manipulations of the training task sufficed to produce the standard effects obtained in PE and PL. In contrast to prior studies, we demonstrated that some degree of PE can be acquired in a task-irrelevant manner, similar to PL. Task-irrelevant PE resulted in similar shape matching ability compared to the directly trained PE. In addition, learning in both PE and PL generalizes to different untrained conditions, which does not support the idea that PE generalizes while PL is specific. Degrees of generalization can be explained by considering the psychological space of the stimuli used for training and the test of transfer.

  2. On Cu diffusion in ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Herklotz, F.; Lavrov, E.V.; Weber, J. [Technische Universitaet Dresden (Germany)


    Copper in ZnO is of special interest since recent theoretical and experimental studies found ferromagnetic behavior of ZnO:Cu at room temperature. In addition, Cu is a deep acceptor in ZnO and one of the causes of the green emission band. Experimental studies of Cu diffusion in bulk ZnO single crystals were carried out in the temperature range 1030 to 1180 C. Concentration profiles of substitutional Cu were determined via IR absorption at 5817 cm{sup -1}. Our findings reveal that the diffusion coefficient of Cu is 7.6 x 10{sup 7} exp(-4.56 eV/k{sub B}T) cm{sup 2}s{sup -1}. This is about a factor of 25 higher than reported in the earlier studies, which probed the total Cu concentration. The discrepancy is explained by the formation of Cu complexes, which occurs at high concentrations. Diffusion mechanisms are discussed.

  3. IEA Wind Task 36 Forecasting (United States)

    Giebel, Gregor; Cline, Joel; Frank, Helmut; Shaw, Will; Pinson, Pierre; Hodge, Bri-Mathias; Kariniotakis, Georges; Sempreviva, Anna Maria; Draxl, Caroline


    Wind power forecasts have been used operatively for over 20 years. Despite this fact, there are still several possibilities to improve the forecasts, both from the weather prediction side and from the usage of the forecasts. The new International Energy Agency (IEA) Task on Wind Power Forecasting tries to organise international collaboration, among national weather centres with an interest and/or large projects on wind forecast improvements (NOAA, DWD, UK MetOffice, …) and operational forecaster and forecast users. The Task is divided in three work packages: Firstly, a collaboration on the improvement of the scientific basis for the wind predictions themselves. This includes numerical weather prediction model physics, but also widely distributed information on accessible datasets for verification. Secondly, we will be aiming at an international pre-standard (an IEA Recommended Practice) on benchmarking and comparing wind power forecasts, including probabilistic forecasts aiming at industry and forecasters alike. This WP will also organise benchmarks, in cooperation with the IEA Task WakeBench. Thirdly, we will be engaging end users aiming at dissemination of the best practice in the usage of wind power predictions, especially probabilistic ones. The Operating Agent is Gregor Giebel of DTU, Co-Operating Agent is Joel Cline of the US Department of Energy. Collaboration in the task is solicited from everyone interested in the forecasting business. We will collaborate with IEA Task 31 Wakebench, which developed the Windbench benchmarking platform, which this task will use for forecasting benchmarks. The task runs for three years, 2016-2018. Main deliverables are an up-to-date list of current projects and main project results, including datasets which can be used by researchers around the world to improve their own models, an IEA Recommended Practice on performance evaluation of probabilistic forecasts, a position paper regarding the use of probabilistic forecasts

  4. Number & operations task & drill sheets

    CERN Document Server

    Reed, Nat


    For grades 6-8, our State Standards-based combined resource meets the number & operations concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. The task sheets introduce the mathematical concepts to the students around a central problem taken from real-life experiences, while the drill sheets provide warm-up and timed practice questions for the students to strengthen their procedural proficiency skills. Included are problems involving place value, fractions, addition, subtraction and using money. The combined task & drill sheets offer spac

  5. The Role of Reminding in the Effects of Spaced Repetitions on Cued Recall: Sufficient but Not Necessary (United States)

    Wahlheim, Christopher N.; Maddox, Geoffrey B.; Jacoby, Larry L.


    Three experiments examined the role of study-phase retrieval (reminding) in the effects of spaced repetitions on cued recall. Remindings were brought under task control to evaluate their effects. Participants studied 2 lists of word pairs containing 3 item types: single items that appeared once in List 2, within-list repetitions that appeared…

  6. Synthesis of Cu or Cu2O-polyimide nanocomposites using Cu powders and their optical properties (United States)

    Choi, Dong Joo; Maeng, Ju Sung; Ahn, Key-one; Jung, Myoung Jin; Song, Seok Ho; Kim, Young-Ho


    Nanocomposites consisting of Cu or Cu2O nanoparticles in various polyimide (PI) films were successfully prepared using polyamic acid (PAA) and Cu powders. Cu powders were dissolved into PAA solutions, and the solutions were spin-coated onto the substrates. Cu or Cu2O nanoparticles were formed in PI film by curing in a reducing or inert atmosphere, respectively. The Cu nanoparticles were transformed to Cu2O nanoparticles by post-heat treatment in an oxidizing atmosphere after curing in a reducing atmosphere. Transmission electron microscopy showed that uniform, round Cu2O nanoparticles 6.0 nm in diameter were dispersed in the PI film by post-heat treatment. The addition of Cu2O nanoparticles in the 4,4‧-(hexafluoroisopropylidene)diphthalic anhydride-4,4‧-oxydianiline (6FDA-ODA) PI film enhanced the refractive index of the 6FDA-ODA PI film from 1.60 to 1.72 at 633 nm, and the transparency of the nanocomposite film was about 70-90% in the visible region and remained around 90% beyond 550 nm.

  7. Effect of temperature on mechanical alloying of Cu-Zn and Cu-Cr system

    Institute of Scientific and Technical Information of China (English)

    ZUO Ke-sheng; XI Sheng-qi; ZHOU Jin-gen


    Cu-Zn and Cu-Cr powders were milled with an attritor mill at room temperature, -10, -20 and -30 ℃, respectively. Phase transformation and morphology evolution of the alloyed powder were investigated by X-ray diffractometry(XRD), X-ray photoelectron spectroscopy(XPS) and scanning electron microscopy(SEM). The results show that lowering temperature can delay mechanical alloying(MA) process of Cu-Zn system with negative mixing enthalpy, and promote MA process of Cu-Cr system with positive mixing enthalpy. As for Cu-Cr and Cu-Zn powders milled at -10 ℃, lamellar structures are firstly formed, while fewer lamellar particles can be found when the powder is milled at -20 ℃. When the alloyed powder is annealed at 1 000 ℃, Cu(Cr) solid solution is decomposed and Cr precipitates from Cu matrix, whereas Cu(Zn) solid solution keeps stable.

  8. New Production Routes for Medical Isotopes 64Cu and 67Cu Using Accelerator Neutrons (United States)

    Kin, Tadahiro; Nagai, Yasuki; Iwamoto, Nobuyuki; Minato, Futoshi; Iwamoto, Osamu; Hatsukawa, Yuichi; Segawa, Mariko; Harada, Hideo; Konno, Chikara; Ochiai, Kentaro; Takakura, Kosuke


    We have measured the activation cross sections producing 64Cu and 67Cu, promising medical radioisotopes for molecular imaging and radioimmunotherapy, by bombarding a natural zinc sample with 14 MeV neutrons. We estimated the production yields of 64Cu and 67Cu by fast neutrons from \\text{natC(d,n) with 40 MeV 5 mA deuterons. We used the present result together with the evaluated cross section of Zn isotopes. The calculated 64Cu yield is 1.8 TBq (175 g 64Zn) for 12 h of irradiation; the yields of 67Cu by 67Zn(n,p)67Cu and 68Zn(n,x)67Cu were 249 GBq (184 g 67Zn) and 287 GBq (186 g 68Zn) at the end of 2 days of irradiation, respectively. From the results, we proposed a new route to produce 67Cu with very little radionuclide impurity via the 68Zn(n,x)67Cu reaction, and showed the 64Zn(n,p)64Cu reaction to be a promising route to produce 64Cu. Both 67Cu and 64Cu are noted to be produced using fast neutrons.

  9. Bimetallic AgCu/Cu2O hybrid for the synergetic adsorption of iodide from solution. (United States)

    Mao, Ping; Liu, Ying; Liu, Xiaodong; Wang, Yuechan; Liang, Jie; Zhou, Qihang; Dai, Yuexuan; Jiao, Yan; Chen, Shouwen; Yang, Yi


    To further improve the capacity of Cu2O to absorb I(-) anions from solution, and to understand the difference between the adsorption mechanisms of Ag/Cu2O and Cu/Cu2O adsorbents, bimetallic AgCu was doped into Cu2O through a facile solvothermal route. Samples were characterized and employed to adsorb I(-) anions under different experimental conditions. The results show that the Cu content can be tuned by adding different volumes of Ag sols. After doping bimetallic AgCu, the adsorption capacity of the samples can be increased from 0.02 mmol g(-1) to 0.52 mmol g(-1). Moreover, the optimal adsorption is reached within only 240 min. Meanwhile, the difference between the adsorption mechanisms of Ag/Cu2O and Cu/Cu2O adsorbents was verified, and the cooperative adsorption mechanism of the AgCu/Cu2O hybrid was proposed and verified. In addition, the AgCu/Cu2O hybrid showed excellent selectivity, e.g., its adsorption efficiencies are 85.1%, 81.9%, 85.9% and 85.7% in the presence of the Cl(-), CO3(2-), SO4(2-) and NO3(-) competitive anions, respectively. Furthermore, the AgCu/Cu2O hybrid can worked well in other harsh environments (e.g., acidic, alkaline and seawater environments). Therefore, this study is expected to promote the development of Cu2O into a highly efficient adsorbent for the removal of iodide from solution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Effects of temporal trial-by-trial cuing on early and late stages of auditory processing: evidence from event-related potentials. (United States)

    Lampar, Alexa; Lange, Kathrin


    Temporal-cuing studies show faster responding to stimuli at an attended versus unattended time point. Whether the mechanisms involved in this temporal orienting of attention are located early or late in the processing stream has not been answered unequivocally. To address this question, we measured event-related potentials in two versions of an auditory temporal cuing task: Stimuli at the uncued time point either required a response (Experiment 1) or did not (Experiment 2). In both tasks, attention was oriented to the cued time point, but attention could be selectively focused on the cued time point only in Experiment 2. In both experiments, temporal orienting was associated with a late positivity in the timerange of the P3. An early enhancement in the timerange of the auditory N1 was observed only in Experiment 2. Thus, temporal attention improves auditory processing at early sensory levels only when it can be focused selectively.

  11. Modeling copper binding to the amyloid-β peptide at different pH: toward a molecular mechanism for Cu reduction. (United States)

    Furlan, Sara; Hureau, Christelle; Faller, Peter; La Penna, Giovanni


    Oxidative stress, including the production of reactive oxygen species (ROS), has been reported to be a key event in the etiology of Alzheimer's disease (AD). Cu has been found in high concentrations in amyloid plaques, a hallmark of AD, where it is bound to the main constituent amyloid-β (Aβ) peptide. Whereas it has been proposed that Cu-Aβ complexes catalyze the production of ROS via redox-cycling between the Cu(I) and Cu(II) state, the redox chemistry of Cu-Aβ and the precise mechanism of redox reactions are still unclear. Because experiments indicate different coordination environments for Cu(II) and Cu(I), it is expected that the electron is not transferred between Cu-Aβ and reactants in a straightforward manner but involves structural rearrangement. In this work the structures indicated by experimental data are modeled at the level of modern density-functional theory approximations. Possible pathways for Cu(II) reduction in different coordination sites are investigated by means of first-principles molecular dynamics simulations in the water solvent and at room temperature. The models of the ligand reorganization around Cu allow the proposal of a preferential mechanism for Cu-Aβ complex reduction at physiological pH. Models reveal that for efficient reduction the deprotonated amide N in the Ala 2-Glu 3 peptide bond has to be protonated and that interactions in the second coordination sphere make important contributions to the reductive pathway, in particular the interaction between COO(-) and NH(2) groups of Asp 1. The proposed mechanism is an important step forward to a clear understanding of the redox chemistry of Cu-Aβ, a difficult task for spectroscopic approaches as the Cu-peptide interactions are weak and dynamical in nature.

  12. A Population of Assessment Tasks (United States)

    Daro, Phil; Burkhardt, Hugh


    We propose the development of a "population" of high-quality assessment tasks that cover the performance goals set out in the "Common Core State Standards for Mathematics." The population will be published. Tests are drawn from this population as a structured random sample guided by a "balancing algorithm."

  13. Scientists and the Selection Task. (United States)

    Griggs, Richard A.; Ransdell, Sarah E.


    Presents findings of a study of scientists on the Wason four-card selection task, finding little understanding of the effect of disconfirmatory data in assessing conditionals. Found performance influenced by problem content. Explains performance as memory-cueing plus reasoning-by-analogy. (JM)

  14. Computer-Related Task Performance

    DEFF Research Database (Denmark)

    Longstreet, Phil; Xiao, Xiao; Sarker, Saonee


    The existing information system (IS) literature has acknowledged computer self-efficacy (CSE) as an important factor contributing to enhancements in computer-related task performance. However, the empirical results of CSE on performance have not always been consistent, and increasing an individua...

  15. A Population of Assessment Tasks (United States)

    Daro, Phil; Burkhardt, Hugh


    We propose the development of a "population" of high-quality assessment tasks that cover the performance goals set out in the "Common Core State Standards for Mathematics." The population will be published. Tests are drawn from this population as a structured random sample guided by a "balancing algorithm."

  16. Use cases versus task descriptions

    DEFF Research Database (Denmark)

    Lauesen, Søren; Kuhail, Mohammad Amin


    to specify require-ments for the same project: Acquire a new system to support a hotline. [Princi-pal ideas/results] Among the 15 replies, eight used traditional use cases that specified a dialog between users and system. Seven used a related technique, task description, which specified the customer's needs...

  17. Task-Based Writing Instruction (United States)

    Bantis, Alexandros


    The purpose of this study was to investigate the impact of task-based writing instruction, a communicative language-teaching method, on second language acquisition and differentiation of instruction for English language learners during the independent work time instructional component of the Open Court Reading program. Through student-teacher…

  18. On the Tasks of Translation

    Institute of Scientific and Technical Information of China (English)



      Many linguists, translators, and theorists have been arguing over the approaches on translation. While putting these into use a translator may experience many pleasure and problems as well. The purpose of this article is to discuss the tasks of translation and the way of choosing the proper translation approaches according to the author’s own experience of practice.

  19. Cu clustering stage before the crystallization in Fe-Si-B-Nb-Cu amorphous alloys

    DEFF Research Database (Denmark)

    Ohnuma, M.; Hono, K.; Onodera, H.


    The Cu clustering stage before the crystallization of Fe-Si-B-Nb-Cu amorphous alloys have been studied by three dimensional atom probe (3DAP) small-angle neutron scattering (SANS) and high sensitive differential calorimetry (DSC). Cu clustering occurs prior to the onset of the primary crystalliza......The Cu clustering stage before the crystallization of Fe-Si-B-Nb-Cu amorphous alloys have been studied by three dimensional atom probe (3DAP) small-angle neutron scattering (SANS) and high sensitive differential calorimetry (DSC). Cu clustering occurs prior to the onset of the primary...

  20. Lattice dynamics of La 2CuO 4 and YBa 2Cu 3O 7 (United States)

    Kimura, Shunji; Sota, Takayuki; Suzuki, Katsuo


    We report lattice dynamics calculations of La 2CuO 4 and YBa 2Cu 3O 7 where the mode assignment is fully performed. It is found that frequencies of the in-plane bond streching 0 vibration mode phonons are much higher than those of the bond bending 0 vibration mode phonons in La 2CuO 4 while they are close in YBa 2Cu 3O 7. The bond streching mode phonons and the bond bending mode phonons can couple to electrons near E F in YBa 2Cu 3O 7 but the latter can not in La 2CuO 4.

  1. Transition of Resistive Switching to Bidirectional Diode in Cu2O/Cu Nanowires (United States)

    Kim, Deok-kee; Shin, Ho Sun; Song, Jae Yong


    Cu2O/Cu nanowires of about 2 µm length were electrodeposited within anodized aluminum oxide templates in an aqueous acidic solution using template-assisted pulse-reverse electrolysis. In the virgin state, reversible copper filaments were formed by using the copper ions driven by an electric field towards the cathode. Initially, the resistive switching dominated the electrical characteristics of the Cu2O/Cu nanowires due to the low-resistance reversible copper filaments. After the permanent breakup of the copper filaments under the high current density, the Cu2O/Cu nanowire showed bipolar exponential characteristics, which was attributed to mixed ionic and electronic conduction.

  2. Assignment of Cu NQR frequencies and Cu spin-spin relaxation in YBa 2Cu 3O 7-δ (United States)

    Mali, M.; Roos, J.; Brinkmann, D.


    We have repeated and confirmed our previous assignment of the Cu NQR frequencies to the Cu sites 1 and 2 by measuring the intensities of the NQR signals at 31.5. and 22.05 MHz. The pulse spectrometer has been calibrated by means of the 19F NMR signal at the same frequencies. The lower Cu frequency is assigned to Cul. A point charge calculation of the electric field gradient at the Cu sites is in good agreement with experimental data. The ratio of the spin-lattice relaxation times of both Cu isotopes at either site has been determined. Unusual temperature dependences of the Cu spin-spin relaxation times have been measured.

  3. Immortality of Cu damascene interconnects (United States)

    Hau-Riege, Stefan P.


    We have studied short-line effects in fully-integrated Cu damascene interconnects through electromigration experiments on lines of various lengths and embedded in different dielectric materials. We compare these results with results from analogous experiments on subtractively-etched Al-based interconnects. It is known that Al-based interconnects exhibit three different behaviors, depending on the magnitude of the product of current density, j, and line length, L: For small values of (jL), no void nucleation occurs, and the line is immortal. For intermediate values, voids nucleate, but the line does not fail because the current can flow through the higher-resistivity refractory-metal-based shunt layers. Here, the resistance of the line increases but eventually saturates, and the relative resistance increase is proportional to (jL/B), where B is the effective elastic modulus of the metallization system. For large values of (jL/B), voiding leads to an unacceptably high resistance increase, and the line is considered failed. By contrast, we observed only two regimes for Cu-based interconnects: Either the resistance of the line stays constant during the duration of the experiment, and the line is considered immortal, or the line fails due to an abrupt open-circuit failure. The absence of an intermediate regime in which the resistance saturates is due to the absence of a shunt layer that is able to support a large amount of current once voiding occurs. Since voids nucleate much more easily in Cu- than in Al-based interconnects, a small fraction of short Cu lines fails even at low current densities. It is therefore more appropriate to consider the probability of immortality in the case of Cu rather than assuming a sharp boundary between mortality and immortality. The probability of immortality decreases with increasing amount of material depleted from the cathode, which is proportional to (jL2/B) at steady state. By contrast, the immortality of Al-based interconnects is

  4. Who multi-tasks and why? Multi-tasking ability, perceived multi-tasking ability, impulsivity, and sensation seeking.

    Directory of Open Access Journals (Sweden)

    David M Sanbonmatsu

    Full Text Available The present study examined the relationship between personality and individual differences in multi-tasking ability. Participants enrolled at the University of Utah completed measures of multi-tasking activity, perceived multi-tasking ability, impulsivity, and sensation seeking. In addition, they performed the Operation Span in order to assess their executive control and actual multi-tasking ability. The findings indicate that the persons who are most capable of multi-tasking effectively are not the persons who are most likely to engage in multiple tasks simultaneously. To the contrary, multi-tasking activity as measured by the Media Multitasking Inventory and self-reported cell phone usage while driving were negatively correlated with actual multi-tasking ability. Multi-tasking was positively correlated with participants' perceived ability to multi-task ability which was found to be significantly inflated. Participants with a strong approach orientation and a weak avoidance orientation--high levels of impulsivity and sensation seeking--reported greater multi-tasking behavior. Finally, the findings suggest that people often engage in multi-tasking because they are less able to block out distractions and focus on a singular task. Participants with less executive control--low scorers on the Operation Span task and persons high in impulsivity--tended to report higher levels of multi-tasking activity.

  5. The Importance of Context in Task Selection (United States)

    Weiland, Travis


    Context is at the core of any statistical investigation, yet many statistics tasks barely require students to go beyond superficial consideration of the contexts the tasks are situated in. In this article, I discuss a framework for evaluating the level of interaction with context a task requires of students and how to modify tasks to increase the…

  6. Tasks for Easily Modifiable Virtual Environments (United States)

    Swier, Robert


    Recent studies of learner interaction in virtual worlds have tended to select basic tasks involving open-ended communication. There is evidence that such tasks are supportive of language acquisition, however it may also be beneficial to consider more complex tasks. Research in task-based learning has identified features such as non-linguistic…

  7. Cosmetology: Task Analyses. Competency-Based Education. (United States)

    Henrico County Public Schools, Glen Allen, VA. Virginia Vocational Curriculum Center.

    These task analyses are designed to be used in combination with the "Trade and Industrial Education Service Area Resource" in order to implement competency-based education in the cosmetology program in Virginia. The task analysis document contains the task inventory, suggested task sequence lists, and content outlines for the secondary…

  8. The Importance of Context in Task Selection (United States)

    Weiland, Travis


    Context is at the core of any statistical investigation, yet many statistics tasks barely require students to go beyond superficial consideration of the contexts the tasks are situated in. In this article, I discuss a framework for evaluating the level of interaction with context a task requires of students and how to modify tasks to increase the…

  9. Quantifying magnetic exchange in doubly-bridged Cu-X(2)-Cu (X = F, Cl, Br) chains enabled by solid state synthesis of CuF(2)(pyrazine). (United States)

    Lapidus, Saul H; Manson, Jamie L; Liu, Junjie; Smith, Matthew J; Goddard, Paul; Bendix, Jesper; Topping, Craig V; Singleton, John; Dunmars, Cortney; Mitchell, J F; Schlueter, John A


    Solid state techniques involving pressure and temperature have been used to synthesize the fluoride member of the CuX(2)(pyrazine) (X = F, Cl, Br) family of coordination polymers that cannot be crystallized by solution methods. CuF(2)(pyrazine) exhibits unique trans doubly-bridged Cu-F(2)-Cu chains that provide an opportunity to quantify magnetic superexchange in an isostructural Cu-X(2)-Cu series.

  10. Facile synthesis of dendritic Cu by electroless reaction of Cu-Al alloys in multiphase solution

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ying; Liang, Shuhua, E-mail:; Yang, Qing; Wang, Xianhui


    Highlights: • Nano- or micro-scale fractal dendritic copper (FDC) was synthesized by electroless immersing of Cu-Al alloys in CuCl{sub 2} + HCl. • FDC size increases with the increase of Al content in Cu-Al alloys immersed in CuCl{sub 2} + HCl solution. • Nanoscale Cu{sub 2}O was found at the edge of FDC. Nanoporous copper (NPC) can also be obtained by using Cu{sub 17}Al{sub 83} alloy. • The potential difference between CuAl{sub 2} and α-Al phase and the replacement reaction in multiphase solution are key factors. - Abstract: Two-dimensional nano- or micro-scale fractal dendritic coppers (FDCs) were synthesized by electroless immersing of Cu-Al alloys in hydrochloric acid solution containing copper chloride without any assistance of template or surfactant. The FDC size increases with the increase of Al content in Cu-Al alloys immersed in CuCl{sub 2} + HCl solution. Compared to Cu{sub 40}Al{sub 60} and Cu{sub 45}Al{sub 55} alloys, the FDC shows hierarchical distribution and homogeneous structures using Cu{sub 17}Al{sub 83} alloy as the starting alloy. The growth direction of the FDC is <110>, and all angles between the trunks and branches are 60°. Nanoscale Cu{sub 2}O was found at the edge of FDC. Interestingly, nanoporous copper (NPC) can also be obtained through Cu{sub 17}Al{sub 83} alloy. Studies showed that the formation of FDC depended on two key factors: the potential difference between CuAl{sub 2} intermetallic and α-Al phase of dual-phase Cu-Al alloys; a replacement reaction that usually occurs in multiphase solution. The electrochemical experiment further proved that the multi-branch dendritic structure is very beneficial to the proton transfer in the process of catalyzing methanol.

  11. Effect of Cu concentration on morphology of Sn-Ag-Cu solders by mechanical alloying (United States)

    Kao, Szu-Tsung; Duh, Jenq-Gong


    The mechanical alloying (MA) process is considered an alternative approach to produce solder materials. In this study, the effect of Cu concentration in the ternary Sn-3.5Ag-xCu (x=0.2, 0.7, and 1) solder by MA was investigated. The (Cu,Sn) solid solution was precipitated as the Cu6Sn5 intermetallic compound (IMC), which was distributed nonuniformly through the microstructure. The Cu6Sn5 IMC, which was present in the SnAgCu solder with high Cu composition, causes the as-milled MA particle to fracture to a smaller size. Appreciable distinction on morphology of as-milled MA powders with different Cu content was revealed. When the Cu concentration was low (x=0.2), MA particle aggregated to a spherical ingot with large particle size. For higher Cu concentration (x=0.7 and x=1), the MA particle turned to flakes with smaller particle size. The distinction of the milling mechanism of Sn-3.5Ag-xCu (x=0.2, 0.7, and 1) solder by the MA process was discussed. An effective approach was developed to reduce the particle size of the SnAgCu solder from 1 mm down to 10-100 µm by doping the Cu6Sn5 nanoparticle during the MA process. In addition, the differential scanning calorimetry (DSC) results also ensure the compatibility to apply the solder material for the reflow process.

  12. Functional indexes of reactive cognitive control: ERPs in cued go/no-go tasks. (United States)

    Kropotov, Juri D; Ponomarev, Valery A; Pronina, Marina; Jäncke, Lutz


    We aimed to determine the functional meaning of latent (hidden) components decomposed from ERPs, in the context of a go/no-go paradigm. To accomplish this, we used a new group blind source separation method, based on joint diagonalization of covariance matrices of ERPs. Four variants of a frequently used go/no-go paradigm were designed, in which operations of reactive cognitive control, such as conflict detection and action inhibition, were independently manipulated. The results showed that a latent component, generated in the anterior cingulate cortex, induced N2/P3 fluctuation only in conditions in which the prepotent model was violated, and thus can be associated with conflict detection operations. In contrast, the two latent components generated in the vicinity of the central sulcus induced P3-like fluctuations in conditions in which the prepared action was suppressed, and thus can be associated with action inhibition operations. The advantages and limitations of the new blind source separation method in relation to ERP research are also discussed. © 2017 Society for Psychophysiological Research.

  13. Task allocation in a distributed computing system (United States)

    Seward, Walter D.


    A conceptual framework is examined for task allocation in distributed systems. Application and computing system parameters critical to task allocation decision processes are discussed. Task allocation techniques are addressed which focus on achieving a balance in the load distribution among the system's processors. Equalization of computing load among the processing elements is the goal. Examples of system performance are presented for specific applications. Both static and dynamic allocation of tasks are considered and system performance is evaluated using different task allocation methodologies.

  14. Evolution of Task Partitioning in Swarm Robotics


    Ferrante, Eliseo,; Duenez-Guzman, E.; Turgut, A. E.; Wenseleers, Tom


    International audience; Task-partitioning refers to the process whereby a task is divided into two or more sub-tasks. Through task partitioning both efficiency and effectiveness can be improved provided the right environmental conditions. We synthesize self-organized task partitioning behaviors for a swarm of mobile robots using artificial evolution. Through validation experiments, we show that the synthesized behaviors exploits behavioral specialization despite being based on homogeneous ind...

  15. Individual Differences in Secondary Task Performance. (United States)


    task similar to that used by Atkinson and Shiffrin (1968). The spatial task in- volved holding in memory a random pattern of plus signs. In all cases...may serve to attenuate the easy-to-hard correlation. I *1,~ __ __ _ Secondary Task Performance 33 References Atkinson , R. C., & Shiffrin , R. M. Human...aIde if nec.eaar, and Identify by block number) ability, attention, dual task, information processing, individual differences memory , secondary task

  16. Reading and reading-related skills in children using cochlear implants: prospects for the influence of cued speech. (United States)

    Bouton, Sophie; Bertoncini, Josiane; Serniclaes, Willy; Colé, Pascale


    We assessed the reading and reading-related skills (phonemic awareness and phonological short-term memory) of deaf children fitted with cochlear implants (CI), either exposed to cued speech early (before 2 years old) (CS+) or never (CS-). Their performance was compared to that of 2 hearing control groups, 1 matched for reading level (RL), and 1 matched for chronological age (CA). Phonemic awareness and phonological short-term memory were assessed respectively through a phonemic similarity judgment task and through a word span task measuring phonological similarity effects. To assess the use of sublexical and lexical reading procedures, children read pseudowords and irregular words aloud. Results showed that cued speech improved performance on both the phonemic awareness and the reading tasks but not on the phonological short-term memory task. In phonemic awareness and reading, CS+ children obtained accuracy and rapidity scores similar to CA controls, whereas CS- children obtained lower scores than hearing controls. Nevertheless, in phonological short-term memory task, the phonological similarity effect of both CI groups was similar. Overall, these results support the use of cued speech to improve phonemic awareness and reading skills in CI children.

  17. Measuring attention using the Posner cuing paradigm: the role of across and within trial target probabilities (United States)

    Hayward, Dana A.; Ristic, Jelena


    Numerous studies conducted within the recent decades have utilized the Posner cuing paradigm for eliciting, measuring, and theoretically characterizing attentional orienting. However, the data from recent studies suggest that the Posner cuing task might not provide an unambiguous measure of attention, as reflexive spatial orienting has been found to interact with extraneous processes engaged by the task's typical structure, i.e., the probability of target presence across trials, which affects tonic alertness, and the probability of target presence within trials, which affects voluntary temporal preparation. To understand the contribution of each of these two processes to the measurement of attentional orienting we assessed their individual and combined effects on reflexive attention elicited by a spatially nonpredictive peripheral cue. Our results revealed that the magnitude of spatial orienting was modulated by joint changes in the global probability of target presence across trials and the local probability of target presence within trials, while the time course of spatial orienting was susceptible to changes in the probability of target presence across trials. These data thus raise important questions about the choice of task parameters within the Posner cuing paradigm and their role in both the measurement and theoretical attributions of the observed attentional effects. PMID:23730280

  18. Electrical conductivity of Cu-Li alloys

    Institute of Scientific and Technical Information of China (English)

    朱达川; 宋明昭; 陈家钊; 涂铭旌; 潘海滨


    The electrical conductivity of Cu-Li alloys was studied. And the distribution of electrons near Fermi surface was detected by synchrotron radiation instrument. The results show that the electrical conductivity of Cu-Li alloys decreases from 5. 22 × 10-9 S/m to 3. 69 × 10-9 S/m with the increase of Li content. Li can decrease the oxygen, sulfur and other impurities content in commercial Cu, but Li dissolved in Cu lattice leads to distortion of Cu lattice from 0. 005 %-0. 050 %, affects the valence band of Cu, increases the binding energy of surface electron, and decreases the electron density of Fermi surface simultaneously. So the electrical conductivity decreases gradually with the increase of Li content.

  19. Single-letter coloring and spatial cuing do not eliminate or reduce a semantic contribution to the Stroop effect. (United States)

    Augustinova, Maria; Flaudias, Valentin; Ferrand, Ludovic


    The automaticity of semantic activation in the Stroop task is still the subject of considerable debate (Augustinova & Ferrand, 2007; Manwell, Roberts, & Besner, 2004). The present experiments were designed to assess whether coloring and cuing a single letter (vs. all letters) in the Stroop task reliably eliminates semantically based Stroop interference or whether the elimination observed by Manwell et al. was due to insufficient statistical power. Experiment 1 was an exact replication of the experiment conducted by Manwell and colleagues and involved a large population. Experiment 2 replicated and extended Experiment 1 by controlling for initial fixation. In line with previous findings obtained by Augustinova and Ferrand, both experiments indicated that coloring and cuing a single letter failed to eliminate or even reduce the semantically based Stroop effect. Thus, these results add to the growing body of evidence suggesting that semantic activation in the Stroop task is automatic.

  20. Iotron development of Cu67 radioisotope

    Energy Technology Data Exchange (ETDEWEB)

    Ehst, David A. [Argonne National Lab. (ANL), Argonne, IL (United States)


    The collaboration has developed a method of producing the Cu-67 medical isotope for beta therapy of cancers such as non-Hodgkins melanoma. In particular we have used electron linac production of intense gamma ray beams to convert Zn-68 into Cu-67 in metal targets. The targets are subsequently processed by separating the Cu isotope from the Zn metal using sublimation, with ceramic components to avoid contamination of the final product.

  1. Purity of targets prepared on Cu substrates (United States)

    Méens, A.; Rossini, I.; Sens, J. C.


    The purity of several elemental self-supporting targets usually prepared by evaporation onto soluble Cu substrates has been studied. The targets were analysed by Rutherford backscattering and instrumental neutron activation analysis. Because of the high percentage of Cu observed in some Si targets, further measurements, including transmission electron microscopy, have been performed on Si targets deposited by e-gun bombardment onto Cu and ion-beam sputtering onto betaine.

  2. Analyses of crack growth along interface of patterned wafer-level Cu-Cu bonds

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Hutchinson, John W.


    A preliminary theoretical study is carried out of the role of micron-scale patterning on the interface toughness of bonded Cu-to-Cu nanometer-scale films. The work is motivated by the experimental studies of [Tadepalli, R., Turner. K.T., Thompson, C.V., 2008b. Effects of patterning on the interface...... toughness of wafer-level Cu-Cu bonds. Acta Materialia 56, 438-447; Tadepalli, R., Turner, K.T., Thompson, C.V., 2008c. Mixed-mode interface toughness of wafer-level Cu-Cu bonds using asymmetric chevron test. J. Mech. Phys. Solids 56, 707-718.] wherein 400 nm Cu films were deposited in a variety of patterns...... on Si wafer substrates. Specimens were then produced by bringing the Cu surfaces into contact creating thermo-compression bonds. Interface toughness of these specimens was experimentally measured. The present study focuses on interface patterns comprised of bonded strips, called lines, alternating...

  3. Novel Peritonsillar Abscess Task Simulator. (United States)

    Taylor, Steven R; Chang, C W David


    The management of peritonsillar abscesses is a skill developed early in residency training. Although drainage is not technically complicated, the procedure is intimidating to the neophyte. Task simulators have become increasingly common to provide training opportunities in a controlled environment. The authors designed a peritonsillar abscess simulator using a latex moulage of the oral cavity and other common materials. Twelve medical professionals of various levels of experience were instructed to expose, anesthetize, aspirate, and drain the simulated abscess. After completion, a questionnaire was completed by each volunteer. Initial impressions were positive that the model adequately replicated the tasks requisite for abscess drainage and was suitable as an instructional device. The initial construct cost was approximately 10 dollars, with disposables costing roughly 25 cents. Further research is under way to formally assess the simulator for face, content, and construct validity.

  4. Neural mechanisms underlying the cost of task switching: an ERP study.

    Directory of Open Access Journals (Sweden)

    Ling Li

    Full Text Available BACKGROUND: When switching from one task to a new one, reaction times are prolonged. This phenomenon is called switch cost (SC. Researchers have recently used several kinds of task-switching paradigms to uncover neural mechanisms underlying the SC. Task-set reconfiguration and passive dissipation of a previously relevant task-set have been reported to contribute to the cost of task switching. METHODOLOGY/PRINCIPAL FINDINGS: An unpredictable cued task-switching paradigm was used, during which subjects were instructed to switch between a color and an orientation discrimination task. Electroencephalography (EEG and behavioral measures were recorded in 14 subjects. Response-stimulus interval (RSI and cue-stimulus interval (CSI were manipulated with short and long intervals, respectively. Switch trials delayed reaction times (RTs and increased error rates compared with repeat trials. The SC of RTs was smaller in the long CSI condition. For cue-locked waveforms, switch trials generated a larger parietal positive event-related potential (ERP, and a larger slow parietal positivity compared with repeat trials in the short and long CSI condition. Neural SC of cue-related ERP positivity was smaller in the long RSI condition. For stimulus-locked waveforms, a larger switch-related central negative ERP component was observed, and the neural SC of the ERP negativity was smaller in the long CSI. Results of standardized low resolution electromagnetic tomography (sLORETA for both ERP positivity and negativity showed that switch trials evoked larger activation than repeat trials in dorsolateral prefrontal cortex (DLPFC and posterior parietal cortex (PPC. CONCLUSIONS/SIGNIFICANCE: The results provide evidence that both RSI and CSI modulate the neural activities in the process of task-switching, but that these have a differential role during task-set reconfiguration and passive dissipation of a previously relevant task-set.

  5. Spatial part-set cuing facilitation. (United States)

    Kelley, Matthew R; Parasiuk, Yuri; Salgado-Benz, Jennifer; Crocco, Megan


    Cole, Reysen, and Kelley [2013. Part-set cuing facilitation for spatial information. Journal of Experimental Psychology: Learning, Memory, & Cognition, 39, 1615-1620] reported robust part-set cuing facilitation for spatial information using snap circuits (a colour-coded electronics kit designed for children to create rudimentary circuit boards). In contrast, Drinkwater, Dagnall, and Parker [2006. Effects of part-set cuing on experienced and novice chess players' reconstruction of a typical chess midgame position. Perceptual and Motor Skills, 102(3), 645-653] and Watkins, Schwartz, and Lane [1984. Does part-set cuing test for memory organization? Evidence from reconstructions of chess positions. Canadian Journal of Psychology/Revue Canadienne de Psychologie, 38(3), 498-503] showed no influence of part-set cuing for spatial information when using chess boards. One key difference between the two procedures was that the snap circuit stimuli were explicitly connected to one another, whereas chess pieces were not. Two experiments examined the effects of connection type (connected vs. unconnected) and cue type (cued vs. uncued) on memory for spatial information. Using chess boards (Experiment 1) and snap circuits (Experiment 2), part-set cuing facilitation only occurred when the stimuli were explicitly connected; there was no influence of cuing with unconnected stimuli. These results are potentially consistent with the retrieval strategy disruption hypothesis, as well as the two- and three-mechanism accounts of part-set cuing.


    NARCIS (Netherlands)

    Berger, R


    In the Li-Cu-O system two new ternary phases have been found, tentatively described by the stoichiometries LiCu3O3 and LiCu2O2, and both containing Cu(I) and Cu(II). They exhibit p-type "hopping" conduction owing to localized charge carriers. Their powder patterns are successfully indexed on high-sy

  7. Biomarker validation of a cued recall memory deficit in prodromal Alzheimer disease. (United States)

    Wagner, M; Wolf, S; Reischies, F M; Daerr, M; Wolfsgruber, S; Jessen, F; Popp, J; Maier, W; Hüll, M; Frölich, L; Hampel, H; Perneczky, R; Peters, O; Jahn, H; Luckhaus, C; Gertz, H-J; Schröder, J; Pantel, J; Lewczuk, P; Kornhuber, J; Wiltfang, J


    To compare cued recall measures with other memory and nonmemory tests regarding their association with a biomarker profile indicative of Alzheimer disease (AD) in CSF among patients with mild cognitive impairment (MCI). Data were obtained by the German Dementia Competence Network. A total of 185 memory clinic patients fulfilling broad criteria for MCI (1 SD deficit in memory tests or in nonmemory tests) were assessed with an extended neuropsychological battery, which included the Free and Cued Selective Reminding Test (FCSRT), the word list learning task from the Consortium to Establish a Registry for Alzheimer's Disease neuropsychological battery (CERAD-NP), and the Logical Memory (LM) paragraph recall test from the Wechsler Memory Scale-Revised. CSF was obtained from all patients. A total of 74 out of 185 subjects with MCI (40%) had a CSF profile consistent with AD (Aβ(1-42)/tau ratio; CSF AD+ group). FCSRT measures reflecting both free and cued recall discriminated best between CSF AD+ and CSF AD- patients, and significantly improved CSF AD classification accuracy, as compared with CERAD delayed recall and LM delayed recall. Cued recall deficits are most closely associated with CSF biomarkers indicative of AD in subjects with MCI. This novel finding complements results from prospective clinical studies and provides further empirical support for cued recall as a specific indicator of prodromal AD, in line with recently proposed research criteria.

  8. Delocalized mixed-valence bi- and trinuclear complexes with short Cu-Cu bonds. (United States)

    Yang, Lei; Powell, Douglas R; Klein, Eric L; Grohmann, Andreas; Houser, Robert P


    Two mixed-valence copper complexes were synthesized with ligands N-(2-pyridylmethyl)acetamide (Hpmac) and N,N'-(2-methyl-2-pyridylpropan-1,3-diyl)bis(acetamide) (H2pp(ac)2). Dimer [Cu2(pmac)2]OTf and trimer [Cu3(pp(ac)2)2].NaOTf both contain fully delocalized, mixed-valence Cu(1.5)Cu(1.5) moieties.

  9. Synthesis, Characterization and Catalytic Activity of Cu/Cu2O Nanoparticles Prepared in Aqueous Medium

    Directory of Open Access Journals (Sweden)

    Sayed M. Badawy


    Full Text Available Copper/Copper oxide (Cu/Cu2O nanoparticles were synthesized by modified chemical reduction method in an aqueous medium using hydrazine as reducing agent and copper sulfate pentahydrate as precursor. The Cu/Cu2O nanoparticles were characterized by X-ray Diffraction (XRD, Energy Dispersive X-ray Fluorescence (EDXRF, Scanning Electron Microscope (SEM, and Transmission Electron Microscope (TEM. The analysis revealed the pattern of face-centered cubic (fcc crystal structure of copper Cu metal and cubic cuprites structure for Cu2O. The SEM result showed monodispersed and agglomerated particles with two micron sizes of about 180 nm and 800 nm, respectively. The TEM result showed few single crystal particles of face-centered cubic structures with average particle size about 11-14 nm. The catalytic activity of Cu/Cu2O nanoparticles for the decomposition of hydrogen peroxide was investigated and compared with manganese oxide MnO2. The results showed that the second-order equation provides the best correlation for the catalytic decomposition of H2O2 on Cu/Cu2O. The catalytic activity of hydrogen peroxide by Cu/Cu2O is less than the catalytic activity of MnO2 due to the presence of copper metal Cu with cuprous oxide Cu2O. © 2015 BCREC UNDIP. All rights reservedReceived: 6th January 2015; Revised: 14th March 2015; Accepted: 15th March 2015How to Cite: Badawy, S.M., El-Khashab, R.A., Nayl, A.A. (2015. Synthesis, Characterization and Catalytic Activity of Cu/Cu2O Nanoparticles Prepared in Aqueous Medium. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (2: 169-174. (doi:10.9767/bcrec.10.2.7984.169-174 Permalink/DOI:  

  10. Measurement of thermal contact resistance at Cu-Cu interface

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Myung Su; Choi, Yeon Suk [Korea Basic Science Institute, Daejeon,(Korea, Republic of)


    The thermal contact resistance (TCR) is one of the important components in the cryogenic systems. Especially, cryogenic measurement devices using a cryocooler can be affected by TCR because the systems have to consist of several metal components in contact with each other for heat transferring to the specimen without cryogen. Therefore, accurate measurement and understanding of TCR is necessary for the design of cryogenic measurement device using a cryocooler. The TCR occurs at the interface between metals and it can be affected by variable factors, such as roughness of metal surface, contact area and contact pressure. In this study, we designed TCR measurement system at various temperatures using a cryocooler as a heat sink and used steady state method to measure the TCR between metals. The copper is selected as a specimen in the experiment because it is widely used as a heat transfer medium in the cryogenic measurement devices. The TCR between Cu and Cu is measured for various temperatures and contact pressures. The effect of the interfacial materials on the TCR is also investigated.

  11. Fuel oil quality task force

    Energy Technology Data Exchange (ETDEWEB)

    Laisy, J.; Turk, V. [R.W. Beckett Corp., Elyria, OH (United States)


    In April, 1996, the R.W. Beckett Corporation became aware of a series of apparently unrelated symptoms that made the leadership of the company concerned that there could be a fuel oil quality problem. A task force of company employees and industry consultants was convened to address the topic of current No. 2 heating oil quality and its effect on burner performance. The task force studied changes in fuel oil specifications and trends in properties that have occurred over the past few years. Experiments were performed at Beckett and Brookhaven National Laboratory to understand the effect of changes in some fuel oil properties. Studies by other groups were reviewed, and field installations were inspected to gain information about the performance of fuel oil that is currently being used in the U.S. and Canada. There was a special concern about the use of red dye in heating oils and the impact of sulfur levels due to the October, 1993 requirement of low sulfur (<0.05%) for on-highway diesel fuel. The results of the task force`s efforts were published in July, 1996. The primary conclusion of the task force was that there is not a crisis or widespread general problem with fuel oil quality. Localized problems that were seen may have been related to refinery practices and/or non-traditional fuel sources. System cleanliness is very important and the cause of many oil burner system problems. Finally, heating oil quality should get ongoing careful attention by Beckett engineering personnel and heating oil industry groups.

  12. Measuring Multi-tasking Ability (United States)


    research. Table 2. Candidate MT Jobs Emergency Room Nurse Emergency Medical Technician Emergency Room Physician Intensive Care Nurse Floor Nurse Waitress ...the ICU and floor nurses, chefs, Army combat leaders, LCAC Craftmasters and LCAC Navigators who educated us about multi- tasking in the working world...different for intensive care nurses than for floor nurses. Hence, individuals were interviewed who had performed a variety of food preparation

  13. 78 FR 63208 - UPDATE-Meeting of the Community Preventive Services Task Force (Task Force) (United States)


    ... Services Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention (CDC), Department of... Force (Task Force). The in-person Task Force meeting is being replaced by an abbreviated conference call... necessary scientific and logistical support for the meeting. The Task Force is an independent,......

  14. 78 FR 2996 - Meeting of the Community Preventive Services Task Force (Task Force) (United States)


    ... Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention (CDC), Department of Health... Prevention (CDC) announces the next meeting of the Community Preventive Services Task Force (Task Force). The Task Force is independent and nonfederal. Its members are nationally known leaders in public...

  15. 77 FR 56845 - Meeting of the Community Preventive Services Task Force (Task Force) (United States)


    ... Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention (CDC), Department of Health... Prevention (CDC) announces the next meeting of the Community Preventive Services Task Force (Task Force). The Task Force is independent and nonfederal. Its members are nationally known leaders in public...

  16. 78 FR 59939 - Meeting of the Community Preventive Services Task Force (Task Force) (United States)


    ... Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention (CDC), Department of Health..., announcing the next meeting of the Community Preventive Services Task Force (Task Force). The document did... inability to attend the Task Force meeting due to the strict security regulations on federal...

  17. Learner-Learner Interaction during Collaborative Pragmatic Tasks: The Role of Cognitive and Pragmatic Task Demands (United States)

    Kim, YouJin; Taguchi, Naoko


    Previous task complexity studies have suggested that learners produce more negotiation of meaning opportunities during complex tasks than simple tasks (Robinson, 2011). The present study builds on the existing task complexity literature by examining the impact of task complexity and pragmatic situational demands on the number of learning…

  18. Alloying effect via comparative studies of ethanol dehydrogenation on Cu(1 1 1), Cu3Pd(1 1 1), and Cu3Pt(1 1 1) (United States)

    Wu, Ruitao; Wang, Lichang


    Ethanol dehydrogenations on Cu(1 1 1), Cu3Pd(1 1 1), and Cu3Pt(1 1 1) were studied using density functional theory with a PBE functional. The α-C-H and β-C-H scissions are endothermic on all surfaces while the O-H scission is exothermic on Cu(1 1 1) and Cu3Pt(1 1 1) but endothermic on Cu3Pd(1 1 1). The ethanol dehydrogenation occurs on Cu(1 1 1) through both α-C-H and O-H scissions but on Cu3Pd(1 1 1) and Cu3Pt(1 1 1) through only α-C-H scission. Furthermore, alloying Pt or Pd with Cu shows an increase in reaction rate at 493 K by more than 3 orders of magnitude, thus illustrating the promise of alloying Pt or Pd in Cu catalysts for ethanol dehydrogenation.

  19. Toxicity of CuO nanoparticles and Cu ions to tight epithelial cells from Xenopus laevis (A6)

    DEFF Research Database (Denmark)

    Thit, Amalie; Selck, Henriette; Bjerregaard, Henning F.


    ) was used to investigate toxicity of copper (Cu) in 3 different forms; Cu ions (Cu2+), CuO NPs (6 nm) and poly-dispersed CuO NPs (100 nm, poly-CuO). Continuous exposures at concentrations of 143–200 μM demonstrated that cytotoxicity differed among the 3 Cu forms tested and that the effects depend on cell...... state (dividing or differentiated). Dividing cells treated with poly-CuO, CuO NPs (6 nm) or Cu2+ showed cell cycle arrest and caused significant increase in cell death via apoptosis after 48 h, 6 and 7 days of treatment, respectively. Treatment with either CuO NPs (6 nm) or Cu2+ caused significant...... decrease in cell proliferation. Treatments of differentiated cells, revealed the same patterns of toxicity for Cu forms tested, but after shorter exposure periods....

  20. Effects of temporal and spatial cueing on anticipatory postural control in a rapid interceptive task. (United States)

    Huntley, Andrew H; Zettel, John L


    Balance disruptions induced by voluntary focal arm actions are accommodated via anticipatory postural adjustments, but how this coordinated control is organized by the central nervous system remains unclear: either as combined or separate streams of postural-focal motor commands. For example, a focal arm task that dictates extremely tight temporal constraints may induce a focal response in absence of an anticipatory postural adjustment, providing evidence for separate focal-postural control streams. This study sought to probe the organization of focal-postural control via an interceptive task with very little available response time, and to determine whether focal-postural coordination depends on temporal and/or spatial foreknowledge of the task. Ten healthy young adults (5 males and 5 females; 20-29 years) reacted to catch a ball when standing under four conditions of temporal and spatial foreknowledge. Response onset was characterized by muscle activity from both postural and focal arm muscles. The catching task resulted in rapid muscle responses, but there was no difference between the fastest focal and postural muscle onsets. As expected, temporal cuing resulted in faster focal and postural onsets compared to spatial and control cuing trials. The accompaniment and time-locking of focal and postural muscle onsets, suggests that postural-focal coupling remains intact even under external time constraints and provides evidence for a single combined command stream of postural and focal control under such circumstances.

  1. SII and the fronto-parietal areas are involved in visually cued tactile top-down spatial attention: a functional MRI study. (United States)

    Wu, Qiong; Li, Chunlin; Li, Yujie; Sun, Hongzan; Guo, Qiyong; Wu, Jinglong


    Visual cue-oriented, tactile top-down attention (vTA) has been well investigated behaviorally. However, vTA-related brain activation remains unclear, and whether SI (primary somatosensory cortex) or SII (secondary somatosensory cortex) is modulated by the top-down process of tactile cognition remains particularly controversial. We used the Posner paradigm in which a visual spatial cue directed attention to a tactile target [tactile spatial attention (TS) task]. The TS is compared with a visual nonspatially cued, tactile attention task [tactile neutral attention (TN) task]. The behavioral results showed no significant differences between the TS and TN tasks. However, we considered the possibility that the visual spatial hint affected the TS neural network. Brain-imaging data showed that the inferior parietal lobe was activated more during the TS task than during the TN task. Furthermore, we present evidence to support SII modulation by top-down processing during the TS task.

  2. Response of the Cu(II) ion selective electrode to Cu titration in artificial and natural shore seawater and in the measurement of the Cu complexation capacity. (United States)

    Rivera-Duarte, Ignacio; Zirino, Alberto


    The Orion 94-29 Cu(II) jalpaite ion selective electrode (Cu-ISE) was used to measure both the concentration of the aqueous free Cu(II) ion ([Cu(II)aq]) and its changes due to additions of Cu, in artificial seawater (ASW) and in seawater from San Diego Bay, CA. The range of free copper ion (i.e., pCu, -log [Cu(II)aq]) determined in seawater samples from the San Diego Bay area (11.3-12.6, 11.9 +/- 0.4, average +/- SD) is consistent with that previously reported for estuarine and coastal areas (10.9-14.1). The changes in [Cu(II)aq] as a result of the additions of Cu were used to determine the Cu complexation capacity (Cu-CC), which has a measured range (2.7 x 10(-8)-2.0 x 10(-7) M; 7.6 x 10(-8) +/- 4.8 x 10(-8) M) comparable to the range of values previously reported for estuarine and coastal zones (i.e., L1+L2, 1.1 x 10(-8)-2.0 x 10(-7) M). The narrow range of pCu at the Cu-CC (pCuCu-CC, 11.1-11.9, 11.5 +/- 0.2) indicates the predominant role of the Cu-CC in regulating the concentration of ambient Cu(II)aq to a level < or =1 x 10(-11) M Cu(II)aq. These results attest to the capability of the Cu-ISE to measure pCu and Cu-CC in aquatic coastal environments with relatively high total Cu concentrations and organic loads, such as those from heavily used coasts and bays.

  3. Quality of Language and Purpose of Task: Patterns of Learners' Language on Two Oral Communication Tasks. (United States)

    Bygate, Martin


    Examines the performance of Hungarian secondary school students on two types of unscripted tasks--an argument task and a narrative task. Focuses on grammatical patterns of learner language, and reports significant differences in the learners' performance. (Author/VWL)

  4. Interfacial Reaction of Sn-Ag-Cu Lead-Free Solder Alloy on Cu: A Review


    Liu Mei Lee; Ahmad Azmin Mohamad


    This paper reviews the function and importance of Sn-Ag-Cu solder alloys in electronics industry and the interfacial reaction of Sn-Ag-Cu/Cu solder joint at various solder forms and solder reflow conditions. The Sn-Ag-Cu solder alloys are examined in bulk and in thin film. It then examines the effect of soldering conditions to the formation of intermetallic compounds such as Cu substrate selection, structural phases, morphology evolution, the growth kinetics, temperature and time is also disc...

  5. Dopamine D3 Receptors Modulate the Ability of Win-Paired Cues to Increase Risky Choice in a Rat Gambling Task. (United States)

    Barrus, Michael M; Winstanley, Catharine A


    Similar to other addiction disorders, the cues inherent in many gambling procedures are thought to play an important role in mediating their addictive nature. Animal models of gambling-related behavior, while capturing dimensions of economic decision making, have yet to address the impact that these salient cues may have in promoting maladaptive choice. Here, we determined whether adding win-associated audiovisual cues to a rat gambling task (rGT) would influence decision making. Thirty-two male Long-Evans rats were tested on either the cued or uncued rGT. In these tasks, animals chose between four options associated with different magnitudes and frequencies of reward and punishing time-out periods. As in the Iowa Gambling Task, favoring options associated with smaller per-trial rewards but smaller losses and avoiding the tempting "high-risk, high-reward" decks maximized profits. Although the reinforcement contingencies were identical in both task versions, rats' choice of the disadvantageous risky options was significantly greater on the cued task. Furthermore, a D3 receptor agonist increased choice of the disadvantageous options, whereas a D3 antagonist had the opposite effects, only on the cued task. These findings are consistent with the reported role of D3 receptors in mediating the facilitatory effects of cues in addiction. Collectively, these results indicate that the cued rGT is a valuable model with which to study the mechanism by which salient cues can invigorate maladaptive decision making, an important and understudied component of both gambling and substance use disorders. Significance statement: We used a rodent analog of the Iowa Gambling Task to determine whether the addition of audiovisual cues would affect choice preferences. Adding reward-concurrent cues significantly increased risky choice. This is the first clear demonstration that reward-paired cues can bias cost/benefit decision making against a subject's best interests in a manner concordant

  6. Bubbfil electrospinning of PA66/Cu nanofibers

    Directory of Open Access Journals (Sweden)

    Li Ya


    Full Text Available Different PA66/Cu nanofibers were prepared under various electrospinning parameters through bubbfil electrospinning. The process parameters were determined. Cuprum particles with different size were added to PA66 solution to produce PA6/66-Cu composite nanofibers. The influence of cuprum nanoparticle size on the PA66 nanofibers was analyzed.

  7. Interfacial Phenomena in Al/Al, Al/Cu, and Cu/Cu Joints Soldered Using an Al-Zn Alloy with Ag or Cu Additions (United States)

    Pstruś, Janusz; Gancarz, Tomasz


    The studies of soldered joints were carried out in systems: Al/solder/Al, Al/solder/Cu, Cu/solder/Cu, where the solder was (Al-Zn)EUT, (Al-Zn)EUT with 0.5, 1.0, and 1.5 at.% of Ag and (Al-Zn)EUT with 0.5, 1.0, and 1.5 at.% of Cu addition. Brazing was performed at 500 °C for 3 min. The EDS analysis indicated that the composition of the layers starting from the Cu pad was CuZn, Cu5Zn8, and CuZn4, respectively. Wetting tests were performed at 500 °C for 3, 8, 15, and 30 min, respectively. Thickness of the layers and their kinetics of growth were measured based on the SEM micrographs. The formation of interlayers was not observed from the side of Al pads. On the contrary, dissolution of the Al substrate and migration of Al-rich particles into the bulk of the solder were observed.

  8. Indium-free, highly transparent, flexible Cu2O/Cu/Cu2O mesh electrodes for flexible touch screen panels (United States)

    Kim, Dong-Ju; Kim, Hyo-Joong; Seo, Ki-Won; Kim, Ki-Hyun; Kim, Tae-Wong; Kim, Han-Ki


    We report on an indium-free and cost-effective Cu2O/Cu/Cu2O multilayer mesh electrode grown by room temperature roll-to-roll sputtering as a viable alternative to ITO electrodes for the cost-effective production of large-area flexible touch screen panels (TSPs). By using a low resistivity metallic Cu interlayer and a patterned mesh structure, we obtained Cu2O/Cu/Cu2O multilayer mesh electrodes with a low sheet resistance of 15.1 Ohm/square and high optical transmittance of 89% as well as good mechanical flexibility. Outer/inner bending test results showed that the Cu2O/Cu/Cu2O mesh electrode had a mechanical flexibility superior to that of conventional ITO films. Using the diamond-patterned Cu2O/Cu/Cu2O multilayer mesh electrodes, we successfully demonstrated TSPS of the flexible film-film type and rigid glass-film-film type TSPs. The TSPs with Cu2O/Cu/Cu2O mesh electrode were used to perform zoom in/out functions and multi-touch writing, indicating that these electrodes are promising cost-efficient transparent electrodes to substitute for conventional ITO electrodes in large-area flexible TSPs.

  9. Indium-free, highly transparent, flexible Cu2O/Cu/Cu2O mesh electrodes for flexible touch screen panels

    National Research Council Canada - National Science Library

    Kim, Dong-Ju; Kim, Hyo-Joong; Seo, Ki-Won; Kim, Ki-Hyun; Kim, Tae-Wong; Kim, Han-Ki


    ... production of large-area flexible touch screen panels (TSPs). By using a low resistivity metallic Cu interlayer and a patterned mesh structure, we obtained Cu2O/Cu/Cu2O multilayer mesh electrodes with a low sheet resistance of 15.1...


    Institute of Scientific and Technical Information of China (English)

    CHEN Xinhua; DONG Junhua; HAN Enhou; KE Wei


    In order to investigate the distribution of Cu and its effect on the microstructure of Cu-bearing steel, a series of mild steels containing different contents of Cu are developed by vacuum electric arc furnace. These steels are annealed at 1 260 ℃, 1 100 ℃ and 1 000 ℃ respectively for one hour and followed by furnace cooling to room temperature to simulate the heat treatment before the rolling process. The results show that Cu did not obviously segregate in annealed steels. The scanning electron microscope (SEM) observation show that the main microstructures in Cu-bearing steel are ferrite and pearlite; The volume fraction of pearlite in steel increase with increasing Cu content. The grain size reduces with the decrease of annealing temperature. The results of energy dispersive X-ray analysis (EDXA) suggest that the Cu content in pearlite is higher than that in ferrite, which means that the microstructure-segregation of Cu exists. However, the cast specimens show that Cu content in MnS and S-rich phase is very high, and Cu changed the distribution of MnS in steel. In addition, the optimal Cu content in steel between 0.2%~0.4% and the optimal annealing temperature between 1100~1 200 ℃ are determined by the economical and practical principles.


    Institute of Scientific and Technical Information of China (English)



    @@ To Chinese students who are learning English as a foreign language, the "intensive reading" course is of great practical value,especially in the intermediate stage,i.e.senior-middle school or the second or third year in college. "Intensive reading"implies the recognition of the configuration, pronunciation, grammatical inflexion and structure of words, sentences, paragraphs, and the whole text. It strength ens listening and speaking, affords language, content, and models for writing.It helps the student lay a solid foundation of the language. Thus, the tasks assigned to the "intensive reading" are worth studying.

  12. Task descriptions versus use cases

    DEFF Research Database (Denmark)

    Lauesen, Søren; Kuhail, Mohammad Amin


    Use cases are widely used as a substantial part of requirements, also when little programming is expected (COTS-based systems, Commercial-Off-The-Shelf). Are use cases effective as requirements? To answer this question, we invited professionals and researchers to specify requirements for the same...... project: Acquire a new system to support a hotline. Among the 15 replies, eight used traditional use cases that specified a dialog between user and system. Seven used a related technique, task description, which specified the customer’s needs without specifying a dialog. It also allowed the analyst...

  13. Use cases versus task descriptions

    DEFF Research Database (Denmark)

    Lauesen, Søren; Kuhail, Mohammad Amin


    Abstract. [Context and motivation] Use cases are widely used as a substantial part of requirements, also when little programming is expected (COTS-based systems). [Question/problem] Are use cases effective as requirements? To an-swer this question, we invited professionals and researchers...... to specify require-ments for the same project: Acquire a new system to support a hotline. [Princi-pal ideas/results] Among the 15 replies, eight used traditional use cases that specified a dialog between users and system. Seven used a related technique, task description, which specified the customer's needs...

  14. Electrochemical behavior of Cu in the (NaCl-KCl-CuCl)molten salt

    Institute of Scientific and Technical Information of China (English)

    Yungang LI; Jie LI; Kuai ZHANG; Limin LIU


    The electrochemical reaction mechanism and electrocrystallization process of Cu on copper electrode in the eutectic NaC1-KC1-CuC1 molten salt were investigated by means of cyclic voltammetry,chronopotentiometry and chronoamperometry technique at 710 ℃.The results show that the electrochemical reaction process of Cu is a quasi-reversible process mix-controlled by Cu+ diffusion rate and electron transport rate; the electrochemical reduction mechanism is Cu++e→Cu; the electrocrystallization process of copper is an instantaneous hemispheroid three-dimensional nucleation process; the Cu+ diffusion coefficient is 4.3×10-4 cm2·s-1 under the experimental conditions.

  15. High volumetric uptake of ammonia using Cu-MOF-74/Cu-CPO-27. (United States)

    Katz, Michael J; Howarth, Ashlee J; Moghadam, Peyman Z; DeCoste, Jared B; Snurr, Randall Q; Hupp, Joseph T; Farha, Omar K


    Cu-MOF-74 (also known as Cu-CPO-27) was identified as a sorbent having one of the highest densities of Cu(ii) sites per unit volume. Given that Cu(ii) in the framework can be thermally activated to yield a five-coordinate Cu(ii) species, we identified this MOF as a potential candidate for maximal volumetric uptake of ammonia. To that end, the kinetic breakthrough of ammonia in Cu-MOF-74/Cu-CPO-27 was examined under both dry and humid conditions. Under dry conditions the MOF exhibited a respectable performance (2.6 vs. 2.9 NH3 per nm(3) for the current record holder HKUST-1), and under 80% relative humidity, the MOF outperformed HKUST-1 (5.9 vs. 3.9 NH3 per nm(3), respectively).

  16. Interfacial Reaction of Sn-Ag-Cu Lead-Free Solder Alloy on Cu: A Review

    Directory of Open Access Journals (Sweden)

    Liu Mei Lee


    Full Text Available This paper reviews the function and importance of Sn-Ag-Cu solder alloys in electronics industry and the interfacial reaction of Sn-Ag-Cu/Cu solder joint at various solder forms and solder reflow conditions. The Sn-Ag-Cu solder alloys are examined in bulk and in thin film. It then examines the effect of soldering conditions to the formation of intermetallic compounds such as Cu substrate selection, structural phases, morphology evolution, the growth kinetics, temperature and time is also discussed. Sn-Ag-Cu lead-free solder alloys are the most promising candidate for the replacement of Sn-Pb solders in modern microelectronic technology. Sn-Ag-Cu solders could possibly be considered and adapted in miniaturization technologies. Therefore, this paper should be of great interest to a large selection of electronics interconnect materials, reliability, processes, and assembly community.

  17. EFFORTS Sub-task report on task 4.2: Cold forming

    DEFF Research Database (Denmark)

    Andreasen, Jan Lasson; Christensen, Thomas Vennick; Bay, Niels


    Task 4.2 is a sub-task of task 4: Physical modelling validation. In sub-task 4.2 experimental analysis of cold forming as regards form filling, interface stresses and forces and moments using sof model materials have been carried out.......Task 4.2 is a sub-task of task 4: Physical modelling validation. In sub-task 4.2 experimental analysis of cold forming as regards form filling, interface stresses and forces and moments using sof model materials have been carried out....

  18. U.S. Preventive Services Task Force (United States)

    ... Public Comment In an effort to make the U.S. Preventive Services Task Force (USPSTF) recommendations clearer and ... Current as of: May 2016 Internet Citation: Home . U.S. Preventive Services Task Force. August 2016. https://www. ...

  19. Pre-task music improves swimming performance. (United States)

    Smirmaul, B P; Dos Santos, R V; Da Silva Neto, L V


    The purpose of this study was to investigate the effects of pre-task music on swimming performance and other psychological variables. A randomized counterbalanced within-subjects (experimental and control condition) design was employed. Eighteen regional level male swimmers performed two 200-m freestyle swimming time trials. Participants were exposed to either 5 minutes of self-selected music (pre-task music condition) or 5 minutes of silence (control condition) and, after 1 minute, performed the swimming task. Swimming time was significantly shorter (-1.44%) in the pre-task music condition. Listening to pre-task music increased motivation to perform the swimming task, while arousal remained unchanged. While fatigue increased after the swimming task in both conditions, vigor, ratings of perceived exertion and affective valence were unaltered. It is concluded, for the first time, that pre-task music improves swimming performance.

  20. Lattice location of implanted Cu in Si

    CERN Document Server

    Wahl, U; Vantomme, A; Langouche, G


    We have implanted the radioactive probe atom $^{67}$Cu ($t_{1/2}$=61.9 h) into single-crystalline Si. Monitoring the $\\beta^{-}$-emission yield from the decay of $^{67}$Cu to $^{67}$Zn as a function of angle from different crystallographic directions allows to determine the lattice location of the Cu atoms by means of the emission channeling effect. We give direct evidence that the majority of implanted Cu occupies near-substitutional sites. As most-likely lattice location we suggest a displacement of 0.51(7) along directions from substitutional sites to bond center positions. The annealing behavior shows that near-substitutional Cu is remarkably stable, and we estimate a dissociation energy of 2.2(3) eV.

  1. Phase equilibrium in Mg-Cu-Y (United States)

    Mezbahul-Islam, Mohammad; Medraj, Mamoun


    Magnesium-based bulk metallic glasses (BMG) have potential in applications ranging from biomedical to sports equipment and the Mg-Cu-Y system offers some of the most promising alloys. Phase relations and ternary solubility of the binary and ternary compounds of this system have been experimentally investigated. The Isothermal section of Mg-Cu-Y system at 673 K for the entire composition range has been constructed. Phase relations in the Cu-rich (>66 at.% Cu) region of the Mg-Cu-Y system has been determined for the first time. The homogeneity range of three ternary compounds has been determined. Solidifications behavior of several key alloys have been discussed based on the differential scanning calorimetry (DSC) experiments and thermodynamic calculations. Extensive analysis of the DSC curves has been carried out to relate them to the corresponding phase transformation reactions and temperatures. Some of the most promising metallic glass forming regions have been analyzed using thermodynamic calculations.

  2. Cue-switch costs in task-switching: cue priming or control processes? (United States)

    Grange, James A; Houghton, George


    In the explicitly cued task-switching paradigm, two cues per task allow separation of costs associated with switching cues from costs of switching tasks. Whilst task-switch costs have become controversial, cue-switch costs are robust. The processes that contribute to cue-switch costs are under-specified in the literature: they could reflect perceptual priming of cue properties, or priming of control processes that form relevant working memory (WM) representations of task demands. Across two experiments we manipulated cue-transparency in an attention-switching design to test the contrasting hypotheses of cue-switch costs, and show that such costs emerge from control processes of establishing relevant WM representations, rather than perceptual priming of the cue itself. When the cues were maximally transparent, cue-switch costs were eradicated. We discuss the results in terms of recent theories of cue encoding, and provide a formal definition of cue-transparency in switching designs and its relation to WM representations that guide task performance.

  3. Enhancement from targets and suppression from cues in fast task-irrelevant perceptual learning. (United States)

    Leclercq, Virginie; Seitz, Aaron R


    Task-irrelevant perceptual learning (TIPL) refers to the phenomenon where the stimulus features of a subject's task are learned when they are consistently presented at times when behaviorally relevant events occur. In this article, we addressed two points concerning TIPL. First, we address the question, are all behaviorally relevant events equal in their impact on encoding processes? Second, we address the hypothesis that TIPL involves mechanisms of the alerting attentional system. Two experiments of fast-TIPL were conducted in which the attentional state of participants was manipulated by using an alerting cue (visual or auditory) that informed participants of the arrival of an upcoming target. Images were presented with task-related stimuli (cues, targets and distractors) and subjects were tested on their memory of those images. Results indicate that memory for target-paired images was enhanced and cue-paired images were suppressed relative to that of distractor-paired images. The alerting cue increased the ability to recall target-paired images presented after this cue, although this result depended on the proportion of cued trials in a session. These results demonstrate a complex interplay between task-elements and the encoding of stimuli paired with them where both enhancement and suppression of task-paired stimuli can be found depending whether those stimuli are paired with task-targets or cues.

  4. Indium-free, highly transparent, flexible Cu2O/Cu/Cu2O mesh electrodes for flexible touch screen panels


    Dong-Ju Kim; Hyo-Joong Kim; Ki-Won Seo; Ki-Hyun Kim; Tae-Wong Kim; Han-Ki Kim


    We report on an indium-free and cost-effective Cu2O/Cu/Cu2O multilayer mesh electrode grown by room temperature roll-to-roll sputtering as a viable alternative to ITO electrodes for the cost-effective production of large-area flexible touch screen panels (TSPs). By using a low resistivity metallic Cu interlayer and a patterned mesh structure, we obtained Cu2O/Cu/Cu2O multilayer mesh electrodes with a low sheet resistance of 15.1?Ohm/square and high optical transmittance of 89% as well as good...

  5. The effects of foreknowledge and task-set shifting as mirrored in cue- and target-locked event-related potentials. (United States)

    Finke, Mareike; Escera, Carles; Barceló, Francisco


    The present study examined the use of foreknowledge in a task-cueing protocol while manipulating sensory updating and executive control in both, informatively and non-informatively pre-cued trials. Foreknowledge, sensory updating (cue switch effects) and task-switching were orthogonally manipulated in order to address the question of whether, and to which extent, the sensory processing of cue changes can partly or totally explain the final task switch costs. Participants responded faster when they could prepare for the upcoming task and if no task-set updating was necessary. Sensory cue switches influenced cue-locked ERPs only when they contained conceptual information about the upcoming task: frontal P2 amplitudes were modulated by task-relevant cue changes, mid-parietal P3 amplitudes by the anticipatory updating of stimulus-response mappings, and P3 peak latencies were modulated by task switching. Task preparation was advantageous for efficient stimulus-response re-mapping at target-onset as mirrored in target N2 amplitudes. However, N2 peak latencies indicate that this process is faster for all repeat trials. The results provide evidence to support a very fast detection of task-relevance in sensory (cue) changes and argue against the view of task repetition benefits as secondary to purely perceptual repetition priming. Advanced preparation may have a stronger influence on behavioral performance and target-locked brain activity than the local effect of repeating or switching the task-set in the current trial.

  6. Reactions in Electrodeposited Cu/Sn and Cu/Ni/Sn Nanoscale Multilayers for Interconnects

    Directory of Open Access Journals (Sweden)

    Pay Ying Chia


    Full Text Available Miniaturization of electronic devices has led to the development of 3D IC packages which require ultra-small-scale interconnections. Such small interconnects can be completely converted into Cu-Sn based intermetallic compounds (IMCs after reflow. In an effort to improve IMC based interconnects, an attempt is made to add Ni to Cu-Sn-based IMCs. Multilayer interconnects consisting of stacks of Cu/Sn/Cu/Sn/Cu or Cu/Ni/Sn/Ni/Sn/Cu/Ni/Sn/Ni/Cu with Ni = 35 nm, 70 nm, and 150 nm were electrodeposited sequentially using copper pyrophosphate, tin methanesulfonic, and nickel Watts baths, respectively. These multilayer interconnects were investigated under room temperature aging conditions and for solid-liquid reactions, where the samples were subjected to 250 °C reflow for 60 s and also 300 °C for 3600 s. The progress of the reaction in the multilayers was monitored by using X-ray Diffraction, Scanning Electron Microscope, and Energy dispersive X-ray Spectroscopy. FIB-milled samples were also prepared for investigation under room temperature aging conditions. Results show that by inserting a 70 nanometres thick Ni layer between copper and tin, premature reaction between Cu and Sn at room temperature can be avoided. During short reflow, the addition of Ni suppresses formation of Cu3Sn IMC. With increasing Ni thickness, Cu consumption is decreased and Ni starts acting as a barrier layer. On the other hand, during long reflow, two types of IMC were found in the Cu/Ni/Sn samples which are the (Cu,Ni6Sn5 and (Cu,Ni3Sn, respectively. Details of the reaction sequence and mechanisms are discussed.

  7. New system for manipulation of nanoobjects based on composite Ti2NiCu/Pt nanotweezers with shape memory effect (United States)

    Zhikharev, A. M.; Irzhak, A. V.; Beresin, M. Y.; Lega, P. V.; Koledov, V. V.; Kasyanov, N. N.; Martynov, G. S.


    We report the new system for manipulation of nanoobjects based on composite Ti2NiCu/Pt nanotweezers with shape memory effect. The design consists of the bimetallic Ti2NiCu/Pt shape memory nanotweezers placed on a tip of electrochemically etched tungsten needle. The semiconductor diode placed on the tip of the needle plays both role of resistive element of the heater and temperature sensor for feedback control loop closing. The device is compatible with existing positioning systems like OmniProbe®, Kleindiek®, etc. and may find numerous practical applications in various tasks of nanotechnology connected with 3D manipulation.

  8. Task Difficulty in Oral Speech Act Production (United States)

    Taguchi, Naoko


    This study took a pragmatic approach to examining the effects of task difficulty on L2 oral output. Twenty native English speakers and 59 Japanese students of English at two different proficiency levels produced speech acts of requests and refusals in a role play task. The task had two situation types based on three social variables:…

  9. A Task Is a Task Is a Task Is a Task... Or Is It? Researching Telecollaborative Teacher Competence Development--The Need for More Qualitative Research (United States)

    Müller-Hartmann, Andreas


    The concept of task has become central not only to an understanding of language learning per se, but also to the design and research of Online Intercultural Exchanges (OIEs). While research on the design of tasks in OIEs has been very productive, we still lack insights into how teachers develop competences in task design on the micro-level.…

  10. Task Repetition and Second Language Speech Processing (United States)

    Lambert, Craig; Kormos, Judit; Minn, Danny


    This study examines the relationship between the repetition of oral monologue tasks and immediate gains in L2 fluency. It considers the effect of aural-oral task repetition on speech rate, frequency of clause-final and midclause filled pauses, and overt self-repairs across different task types and proficiency levels and relates these findings to…

  11. Imagining Mathematics Teaching via Scripting Tasks (United States)

    Zazkis, Rina; Sinclair, Nathalie


    We discuss an innovative task used in teacher education--Lesson Play--that involves presenting a lesson in the form of an interaction between a teacher and students. We describe the motivation for the development of this task and, through specific examples, describe the iterative design process in which the task was refined and improved. We…

  12. What Makes a Mathematical Task Interesting? (United States)

    Nyman, Rimma


    The study addresses the question of what makes a mathematical task interesting to the 9th year students. Semi-structured interviews were carried out with 15 students of purposive selection of the 9th year. The students were asked to recall a task they found interesting and engaging during the past three years. An analysis of the tasks was made…

  13. Task Complexity and Second Language Narrative Discourse. (United States)

    Robinson, Peter


    Examines differences in oral narrative discourse of adult second-language learners of English on narrative tasks simulating the ability to describe events in the Here-and-Now versus the There-and-Then. Results indicate that complex tasks elicit less fluent, but more accurate and complex narration than do simpler tasks. (90 references) (Author/CK)

  14. Research on Task-Based Language Teaching

    Institute of Scientific and Technical Information of China (English)



    This paper begins with a brief introduction to Task-Based Language Teaching(TBLT).The Task-Based Language Teaching(TBLA) has gained popularity in the field of language teaching since the last decade of the 20th century.This paper mainly il ustrates the definition,importance and approaches of Task-Based Language Teaching(TBLA).

  15. An unusual coordination polymer containing Cu(+) ions and featuring possible Cu...Cu `cuprophilic' interactions: poly[di-μ-chlorido-(μ4-3,5-diaminobenzoato-κ(4)O:O':N:N')tricopper(I)(3 Cu-Cu)]. (United States)

    Khosa, Muhammad Kaleem; Wood, Paul T; Humphrey, Simon M; Harrison, William T A


    Compounds containing copper(I) are of interest for their role in biological processes. The nature of short (coordination polymer, [Cu3(C7H7N2O2)Cl2]n, was formed from the in situ reduction of CuCl2 in the presence of 3,5-diaminobenzoic acid and KOH under hydrothermal conditions. Its complex crystal structure contains ten distinct Cu(I) atoms, two of which lie on crystallographic inversion centres. The copper coordination geometries include near-linear CuOCl and CuN2, T-shaped CuOCl2 and distorted tetrahedral CuOCl3 groups. Each Cu(I) atom is also associated with two adjacent metal atoms, with Cu...Cu distances varying from 2.7350 (14) to 3.2142 (13) Å; if all these are regarded as `cuprophilic' interactions, then infinite [-101] zigzag chains of Cu(I) atoms occur in the crystal. The structure is consolidated by N-H...Cl hydrogen bonds.

  16. TASK-1 and TASK-3 may form heterodimers in human atrial cardiomyocytes. (United States)

    Rinné, Susanne; Kiper, Aytug K; Schlichthörl, Günter; Dittmann, Sven; Netter, Michael F; Limberg, Sven H; Silbernagel, Nicole; Zuzarte, Marylou; Moosdorf, Rainer; Wulf, Hinnerk; Schulze-Bahr, Eric; Rolfes, Caroline; Decher, Niels


    TASK-1 channels have emerged as promising drug targets against atrial fibrillation, the most common arrhythmia in the elderly. While TASK-3, the closest relative of TASK-1, was previously not described in cardiac tissue, we found a very prominent expression of TASK-3 in right human auricles. Immunocytochemistry experiments of human right auricular cardiomyocytes showed that TASK-3 is primarily localized at the plasma membrane. Single-channel recordings of right human auricles in the cell-attached mode, using divalent-cation-free solutions, revealed a TASK-1-like channel with a single-channel conductance of about 30pS. While homomeric TASK-3 channels were not found, we observed an intermediate single-channel conductance of about 55pS, possibly reflecting the heteromeric channel formed by TASK-1 and TASK-3. Subsequent experiments with TASK-1/TASK-3 tandem channels or with co-expressed TASK-1 and TASK-3 channels in HEK293 cells or Xenopus oocytes, supported that the 55pS channels observed in right auricles have electrophysiological characteristics of TASK-1/TASK-3 heteromers. In addition, co-expression experiments and single-channel recordings suggest that heteromeric TASK-1/TASK-3 channels have a predominant surface expression and a reduced affinity for TASK-1 blockers. In summary, the evidence for heteromeric TASK-1/TASK-3 channel complexes together with an altered pharmacologic response to TASK-1 blockers in vitro is likely to have further impact for studies isolating ITASK-1 from cardiomyocytes and for the development of drugs specifically targeting TASK-1 in atrial fibrillation treatment.

  17. Atom probe study of Cu-poor to Cu-rich transition during Cu(In,Ga)Se2 growth (United States)

    Couzinie-Devy, F.; Cadel, E.; Barreau, N.; Arzel, L.; Pareige, P.


    Atomic scale chemistry of polycrystalline Cu(In,Ga)Se2 (CIGSe) thin film has been characterized at key points of the 3-stage process using atom probe tomography. 3D atom distributions have been reconstructed when the layer is Cu-poor ([Cu]/([Ga] + [In]) 1), and at the end of the process. Particular attention has been devoted to grain boundary composition and Na atomic distribution within the CIGSe layer. Significant variation of composition is highlighted during the growing process, providing fundamental information helping the understanding of high efficiency CIGSe formation.

  18. An apparent-motion confound causes the negative exogenous cuing effect at SOAs with larger numbers of target locations. (United States)

    Chen, Peii; Mordkoff, J Toby


    Salient but irrelevant stimuli seem to cause an automatic orienting of covert attention, facilitating the detection of targets at the cued location for a brief period of time. However, this finding is highly dependent on the number of possible target locations, at least when the simple detection of targets is all that the task requires. Whereas small numbers of possible target locations (e.g., 2 or 3) produce the well-known advantage in response time for valid cue trials (i.e., a positive cuing effect), larger numbers of possible target locations (e.g., 6 or 8) produce a negative cuing effect. If not explained in terms of a nonattentional mechanism, this latter finding raises serious questions about the standard interpretation of positive cuing effects. The present experiment tested a particular nonattentional mechanism: that a confound between target presence and apparent motion, which occurs only on invalid cue trials, is responsible for negative cuing effect. We reduced or eliminated this confound by the use of a new type of catch trial and eliminated the negative cuing effect with large numbers of target locations.

  19. A new combined process for efficient removal of Cu(II) organic complexes from wastewater: Fe(III) displacement/UV degradation/alkaline precipitation. (United States)

    Xu, Zhe; Gao, Guandao; Pan, Bingcai; Zhang, Weiming; Lv, Lu


    Efficient removal of heavy metals complexed with organic ligands from water is still an important but challenging task now. Herein, a novel combined process, i.e., Fe(III)-displacement/UV degradation/alkaline precipitation (abbreviated as Fe(III)/UV/OH) was developed to remove copper-organic complexes from synthetic solution and real electroplating effluent, and other processes including alkaline precipitation, Fe(III)/OH, UV/OH were employed for comparison. By using the Fe(III)/UV/OH process, some typical Cu(II) complexes, such as Cu(II)-ethylenediaminetetraacetic acid (EDTA), Cu(II)-nitrilotriacetic acid (NTA), Cu(II)-citrate, Cu(II)-tartrate, and Cu(II)-sorbate, each at 19.2 mg Cu/L initially, were efficiently removed from synthetic solution with the residual Cu below 1 mg/L. Simultaneously, 30-48% of total organic carbon was eliminated with exception of Cu(II)-sorbate. Comparatively, the efficiency of other processes was much lower than the Fe(III)/UV/OH process. With Cu(II)-citrate as the model complex, the optimal conditions for the combined process were obtained as: initial pH for Fe(III) displacement, 1.8-5.4; molar ratio of [Fe]/[Cu], 4:1; UV irradiation, 10 min; precipitation pH, 6.6-13. The mechanism responsible for the process involved the liberation of Cu(II) ions from organic complexes as a result of Fe(III) displacement, decarboxylation of Fe(III)-ligand complexes subjected to UV irradiation, and final coprecipitation of Cu(II) and Fe(II)/Fe(III) ions. Up to 338.1 mg/L of Cu(II) in the electroplating effluent could be efficiently removed by the process with the residual Cu(II) below 1 mg/L and the removal efficiency of ∼99.8%, whereas direct precipitation by using NaOH could only result in total Cu(II) removal of ∼8.6%. In addition, sunlight could take the place of UV to achieve similar removal efficiency with longer irradiation time (90 min).

  20. Physiological response of Cu and Cu mine tailing remediation of Paulownia fortunei (Seem) Hemsl. (United States)

    Jiang, Zao-Fa; Huang, Su-Zhen; Han, Yu-Lin; Zhao, Jiu-Zhou; Fu, Jia-Jia


    The physiological responses and Cu accumulation of Paulownia fortunei (Seem) Hemsl. were studied under 15.7-157 μmol L(-1) Cu treatments in liquid culture for 14 days; the impacts of Cu concentration in the seedlings were evaluated under Cu mine tailing culture with acetic acid and EDTA treatment for 60 days. Results showed that the concentrations of Chl-a, Chl-b and Carotenoids significantly increased (p tailing experienced unsuccessful growth and loss of leaves in all treatments due to poor nutrition of the Cu tailing. The dry weight of P. fortunei increased under all the treatments of acetic acid after 60 days exposure. However, dry weight significantly decreased under both levels of EDTA. The Cu concentrations increased significantly in roots and decreased in leaves when each was treated with both concentrations of acetic acid. The Cu concentrations in the roots, stems and leaves increased significantly, and the concentrations of Cu in the stems and leaves under the treatment of 2 μmol L(-1) EDTA reached 189.5 and 763.1 μg g(-1) DW, respectively. The result indicated that SOD, CAT, proline and soluble sugars played an important role in coping with the oxidative stress of copper. Acetic acid could promote growth and EDTA at the experimental levels, which could also enhance Cu absorption and translocation into the stems and leaves of P. fortune. Furthermore, acetic acid and EDTA could be rationally utilized in Cu-contaminated soil.

  1. Facile synthesis of dendritic Cu by electroless reaction of Cu-Al alloys in multiphase solution (United States)

    Wang, Ying; Liang, Shuhua; Yang, Qing; Wang, Xianhui


    Two-dimensional nano- or micro-scale fractal dendritic coppers (FDCs) were synthesized by electroless immersing of Cu-Al alloys in hydrochloric acid solution containing copper chloride without any assistance of template or surfactant. The FDC size increases with the increase of Al content in Cu-Al alloys immersed in CuCl2 + HCl solution. Compared to Cu40Al60 and Cu45Al55 alloys, the FDC shows hierarchical distribution and homogeneous structures using Cu17Al83 alloy as the starting alloy. The growth direction of the FDC is , and all angles between the trunks and branches are 60°. Nanoscale Cu2O was found at the edge of FDC. Interestingly, nanoporous copper (NPC) can also be obtained through Cu17Al83 alloy. Studies showed that the formation of FDC depended on two key factors: the potential difference between CuAl2 intermetallic and α-Al phase of dual-phase Cu-Al alloys; a replacement reaction that usually occurs in multiphase solution. The electrochemical experiment further proved that the multi-branch dendritic structure is very beneficial to the proton transfer in the process of catalyzing methanol.

  2. Evaluation of Cu Ion Concentration Effects on Cu Etching Rate in Chemical-Mechanical Polishing Slurry (United States)

    Nishizawa, Hideaki; Sugiura, Osamu; Matsumura, Yoshiyuki; Kinoshita, Masaharu


    The effects of Cu ion concentration of the different solutions on Cu etching rate were investigated. From the dipping experiment of Cu substrates in different solutions of malic acid, hydrogen peroxide (H2O2), benzotriazole (BTA), and Cu ions, it was revealed that Cu etching rate is increased if the concentration of Cu(II) ions added in the solution is high. This is considered to be caused by the effect of Cu(II) ions on H2O2 molecules. In the solution of pH 7, the Cu etching rate increased markedly between 1.7× 10-4 and 3.4× 10-4 M Cu(II) ion concentrations. The maximum increase in the etching rate was from 990 to 2200 nm/min at a H2O2 concentration of 2 wt %. In the solution of pH 3, a marked change in the etching rate was not observed. Our results show that the concentration of Cu ions on the polishing pad in chemical-mechanical polishing (CMP) process is very important.

  3. Effect of Corrosion Inhibitor, Benzotriazole, in Cu Slurry on Cu Polishing (United States)

    Kim, In-Kwon; Kang, Young-Jae; Kim, Tae-Gon; Park, Jin-Goo


    In this study, the effect of benzotriazole (BTA) in Cu slurry on Cu polishing behavior was investigated as functions of H2O2 and slurry pH. The addition of BTA to slurry effectively prevented Cu from being etched by forming a passivation layer of Cu-BTA regardless of pH and H2O2 concentration in the slurry. The passivation layer on the Cu wafer exhibited a contact angle of 50° in solution with BTA and H2O2. The dynamic etching rate, i.e., the Cu polishing rate using abrasive-free slurry, also decreased when BTA was added to the slurry at pH 2, 4, and 6. The removal rate of Cu in slurry without BTA was strongly dependent on H2O2 concentration and pH. In slurry with BTA, Cu-BTA on the Cu surface prevented the etching of Cu. At pH 2 and 4, the removal rates were lower in slurry with BTA than in slurry without BTA. However, slurries of pH 6 or higher with BTA showed higher removal rates at higher concentrations of H2O2 than 10%, which was explained by the thick passivating oxide layer formed at higher pH and H2O2 concentrations.

  4. Characterization of Cu-exchanged SSZ-13: a comparative FTIR, UV-Vis, and EPR study with Cu-ZSM-5 and Cu-β with similar Si/Al and Cu/Al ratios. (United States)

    Giordanino, Filippo; Vennestrøm, Peter N R; Lundegaard, Lars F; Stappen, Frederick N; Mossin, Susanne; Beato, Pablo; Bordiga, Silvia; Lamberti, Carlo


    Cu-SSZ-13 has been characterized by different spectroscopic techniques and compared with Cu-ZSM-5 and Cu-β with similar Si/Al and Cu/Al ratios and prepared by the same ion exchange procedure. On vacuum activated samples, low temperature FTIR spectroscopy allowed us to appreciate a high concentration of reduced copper centres, i.e. isolated Cu(+) ions located in different environments, able to form Cu(+)(N2), Cu(+)(CO)n (n = 1, 2, 3), and Cu(+)(NO)n (n = 1, 2) upon interaction with N2, CO and NO probe molecules, respectively. Low temperature FTIR, DRUV-Vis and EPR analysis on O2 activated samples revealed the presence of different Cu(2+) species. New data and discussion are devoted to (i) [Cu-OH](+) species likely balanced by one framework Al atom; (ii) mono(μ-oxo)dicopper [Cu2(μ-O)](2+) dimers observed in Cu-ZSM-5 and Cu-β, but not in Cu-SSZ-13. UV-Vis-NIR spectra of O2 activated samples reveal an intense and finely structured d-d quadruplet, unique to Cu-SSZ-13, which is persistent under SCR conditions. This differs from the 22,700 cm(-1) band of the mono(μ-oxo)dicopper species of the O2 activated Cu-ZSM-5, which disappears under SCR conditions. The EPR signal intensity sets Cu-β apart from the others.

  5. Garbage Collection Scheduling of Aperiodic Tasks

    Institute of Scientific and Technical Information of China (English)

    Ning Zhang; Guang-Ze Xiong


    In the previous work of garbage collection (GC) models, scheduling analysis was given based on an assumption that there were no aperiodic mutator tasks. However, it is not true in practical real-time systems. The GC algorithm which can schedule aperiodic tasks is proposed, and the variance of live memory is analyzed. In this algorithm, active tasks are deferred to be processed by GC until the states of tasks become inactive, and the saved sporadic server time can be used to schedule aperiodic tasks. Scheduling the sample task sets demonstrates that this algorithm in this paper can schedule aperiodic tasks and decrease GC work. Thus, the GC algorithm proposed is more flexible and portable.

  6. Assessing Cognitive Load on Web Search Tasks

    CERN Document Server

    Gwizdka, Jacek


    Assessing cognitive load on web search is useful for characterizing search system features and search tasks with respect to their demands on the searcher's mental effort. It is also helpful for examining how individual differences among searchers (e.g. cognitive abilities) affect the search process. We examined cognitive load from the perspective of primary and secondary task performance. A controlled web search study was conducted with 48 participants. The primary task performance components were found to be significantly related to both the objective and the subjective task difficulty. However, the relationship between objective and subjective task difficulty and the secondary task performance measures was weaker than expected. The results indicate that the dual-task approach needs to be used with caution.

  7. Is a "Complex" Task Really Complex? Validating the Assumption of Cognitive Task Complexity (United States)

    Sasayama, Shoko


    In research on task-based learning and teaching, it has traditionally been assumed that differing degrees of cognitive task complexity can be inferred through task design and/or observations of differing qualities in linguistic production elicited by second language (L2) communication tasks. Without validating this assumption, however, it is…

  8. How to Correct a Task Error: Task-Switch Effects Following Different Types of Error Correction (United States)

    Steinhauser, Marco


    It has been proposed that switch costs in task switching reflect the strengthening of task-related associations and that strengthening is triggered by response execution. The present study tested the hypothesis that only task-related responses are able to trigger strengthening. Effects of task strengthening caused by error corrections were…

  9. Adapting Non-Task-Based Materials to Fit a Task-Based Framework

    Institute of Scientific and Technical Information of China (English)



    Analyzes the three -phases--pre -task, task cycle, post -task and their rationale in task -based language teaching, designs corresponding teaching activities after adapting one text from New Horizon College English, so that college English teachers can better understand and use this teaching approach, and then improve the teaching effect and college students'comprehensive application abilities of language.

  10. Microstructures and properties of Cr-Cu/W-Cu bi-layer composite coatings prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jiaping; Feng, Xiaomei; Shen, Yifu; Chen, Cheng; Duan, Cuiyuan [Nanjing Univ. of Aeronautics and Astronautics (China). Dept. of Materials Science and Technology


    Cr-Cu/W-Cu bi-layer coatings with composite structures were fabricated by means of mechanical alloying. The Cr-Cu layer and the W-Cu layer were deposited successively and the as-synthesized bi-layer coating was made up of an inner Cr-Cu layer and an outer W-Cu layer. Microstructures, chemical and phase compositions of the as-prepared coatings were characterized. The results indicated that the bonding between the inner coating and the substrate was improved with the increase of Cu in the raw powder. The annealing treatment of the inner Cr-Cu layer was beneficial to the bonding between the inner Cr-Cu coating and the outer W-Cu coating layer. Mechanical properties such as microhardness, friction and wear resistance were tested. The as-synthesized coating could effectively improve the hardness and wear resistance of the Cu substrate.

  11. Mixed-valence copper coordination polymers based on CuSCN or CuN3 as bridging motifs

    Institute of Scientific and Technical Information of China (English)

    FAN Guang; GAO Shengli; CHEN Sanping; ZENG Minghua; XIE Gang


    Two novel mixed valence copper coordination polymers, [Cu(2-pac)2(CuN3)(H2O)]n (1) and [Cu(2-pac)2(CuSCN)2]n (2), have been prepared through hydrothermal synthesis and analyzed for structure determination, which exhibit two- and three-dimensional structures respectively. In complex (1), zigzag chains of [CuN3]n running parallel to the c direction are interconnected by Cu(2pac)2 to form a two-dimensional layer structure. In complex (2), the arrangement of μ-1,1,3 bridging thiocyanate ligand leads to the formation of ten-membered Cu-SCN- Cu-S-Cu-NCS rings, and each Cu atom is further linked by Cu(2-pac)2 to afford a three-dimensional configuration.

  12. Attentional demands of cued walking in healthy young and elderly adults. (United States)

    Peper, C Lieke E; Oorthuizen, Jolanda K; Roerdink, Melvyn


    Acoustic and visual cues are frequently used in gait rehabilitation. Attuning the steps to the cues is attentionally demanding. We examined the attentional demands of walking to two types of cues using a probe reaction time (RT) task. The steps were cued by either metronome beeps or visual stepping stones projected on a treadmill. The coupling between gait and these cues was assessed using a perturbation paradigm. In view of age-related changes in attentional demands of motor control, both elderly and young adults were tested. RTs were determined for walking to the two types of cues, as well as for three control conditions, viz. uncued walking, standing, and sitting. For all conditions, RTs were higher for elderly adults. However, the difference between elderly and young adults did not vary over conditions. Uncued walking required more attention than did standing and sitting. The attentional demands were further elevated during cued walking, with larger RTs for walking to visual stepping stones than to metronome beeps. Because the coupling to the cues was superior in the stepping stones condition, this type of cues seems to aid cued walking by allocating higher levels of attention to task-relevant information (viz. future footfall positions). Hence, the observed differences between the two cueing types may be associated with the natural dependence of gait on visual information.

  13. Direct synthesis of RGO/Cu{sub 2}O composite films on Cu foil for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Xiangmao; Wang, Kun [Key Laboratory for Ultrafine Materials of the Ministry of Education, Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhao, Chongjun, E-mail: [Key Laboratory for Ultrafine Materials of the Ministry of Education, Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong 2500 (Australia); Qian, Xiuzhen [Key Laboratory for Ultrafine Materials of the Ministry of Education, Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Chen, Shi [School of Information Engineering, Wuhan University of Technology, Wuhan 430070 (China); Li, Zhen, E-mail: [Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong 2500 (Australia); Liu, Huakun; Dou, Shixue [Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong 2500 (Australia)


    Graphical abstract: RGO/Cu{sub 2}O/Cu composites were synthesized by simple hydrothermal treatment of copper foils with graphene oxide, in which the reduction of graphene oxide and the formation of Cu{sub 2}O nanoparticles simultaneously happened in one-pot reaction. These composites can be directly used as electrodes of supercapacitors with the highest specific capacitance of 98.5 F/g at 1 A g{sup −1}, which is much better than that of CuO or Cu{sub 2}O electrodes. -- Highlights: • The RGO/Cu{sub 2}O/Cu composites were obtained by a friendly method in one step. • Improved capacitance performance is realized by the hydrothermal treatment of graphene oxides with Cu foils. • RGO/Cu{sub 2}O/Cu-200 composites exhibit the largest specific capacitance of 98.5 F g{sup −1} at 1 A g{sup −1}. -- Abstract: Reduced graphene oxide/cuprous oxide (RGO/Cu{sub 2}O) composite films were directly synthesized on the surface of copper foil substrates through a straight redox reaction between GO and Cu foil via a hydrothermal approach. Characterization of the resultant composites with X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and field emission scanning electron microscope (FESEM) confirms the formation of Cu{sub 2}O and reduction of GO, in which Cu{sub 2}O nanoparticles were well covered by RGO. The resultant composites (referred to as RGO/Cu{sub 2}O/Cu) were directly used as electrodes for supercapacitors, and their electrochemical performance was assessed by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectrometry (EIS) in 1 M KOH aqueous solution. A specific capacitance of 98.5 F g{sup −1} at 1 A g{sup −1} was obtained, which is much higher than that of pure Cu{sub 2}O prepared under the same conditions, due to the presence of RGO.

  14. Assessing the Cost of Task Switching with a Three-Task Paradigm (United States)

    Remington, Roger W.; Ruthruff, Eric; Johnston, James C.; Connors, Mary M. (Technical Monitor)


    To study task switching when subjects need not inhibit inappropriate responses, we examine tasks with non-overlapping stimulus sets (e.g. color patches and uncolored letters). A new three-task paradigm permits the dissociation of several otherwise confounded variables. We find that performance declines monotonically with increasing time since last performance of a task. Adjusting for the effects of this factor permits a fresh assessment of the relationship between task expectancy and recency (Ruthruff, Remington & Johnston, 1996).

  15. Visuospatial tasks affect locomotor control more than nonspatial tasks in older people.

    Directory of Open Access Journals (Sweden)

    Jasmine C Menant

    Full Text Available Previous research has shown that visuospatial processing requiring working memory is particularly important for balance control during standing and stepping, and that limited spatial encoding contributes to increased interference in postural control dual tasks. However, visuospatial involvement during locomotion has not been directly determined. This study examined the effects of a visuospatial cognitive task versus a nonspatial cognitive task on gait speed, smoothness and variability in older people, while controlling for task difficulty.Thirty-six people aged ≥75 years performed three walking trials along a 20 m walkway under the following conditions: (i an easy nonspatial task; (ii a difficult nonspatial task; (iii an easy visuospatial task; and (iv a difficult visuospatial task. Gait parameters were computed from a tri-axial accelerometer attached to the sacrum. The cognitive task response times and percentage of correct answers during walking and seated trials were also computed.No significant differences in either cognitive task type error rates or response times were evident in the seated conditions, indicating equivalent task difficulty. In the walking trials, participants responded faster to the visuospatial tasks than the nonspatial tasks but at the cost of making significantly more cognitive task errors. Participants also walked slower, took shorter steps, had greater step time variability and less smooth pelvis accelerations when concurrently performing the visuospatial tasks compared with the nonspatial tasks and when performing the difficult compared with the easy cognitive tasks.Compared with nonspatial cognitive tasks, visuospatial cognitive tasks led to a slower, more variable and less smooth gait pattern. These findings suggest that visuospatial processing might share common networks with locomotor control, further supporting the hypothesis that gait changes during dual task paradigms are not simply due to limited attentional

  16. Giant electric conductivity in CuO-Cu interface and its HTSC-like temperature changes

    CERN Document Server

    Osipov, V V; Naumov, S V


    The temperature dependences of the electric conductivity and volt-ampere characteristics (VAC) of the samples, representing the CuO monocrystals, the natural facets whereof are coated with the Cu film, are studied. It is shown that the electric conductivity, related to the Cu films, after electro-chemical or thermal annealing grows multiply up to 1.5 x 10 sup 5 times as compared to the Cu control films on the devitrified glass. The obtained results are explained by formation of the high-conductivity interface layer between CuO and Cu. It is supposed that the giant electric conductivity, its HTSC-like change with the temperature and VAC nonlinearity may be conditioned by formation of superconducting areas with critical temperatures, essentially exceeding 400 K

  17. Effect of reducing agents in the conversion of Cu2O nanocolloid to Cu nanocolloid

    Directory of Open Access Journals (Sweden)

    V. Andal


    Full Text Available Current work reports the conversion of copper (I oxide, nano-colloid to stable copper nanocolloid. Different reduction conditions were attempted to control the stability and size of the Cu nanoparticles. Hydrazine hydrate, ascorbic acid and glucose are found to be good reductants. In our work stable copper nanoparticles are obtained by reducing Cu2O without any special protections like inert gas atmosphere etc. Ascorbic acid, a natural vitamin C not only reduces cuprous oxide but protects the new born copper due to its antioxidant properties. A red shift is observed when Cu2O nanospheres get converted to Cu. UV, XRD, FTIR and TEM were used to characterize the prepared Cu nanoparticles. The mechanism for the growth process of Cu nanomaterials are discussed.

  18. Ferromagnetic Cu-O-Cu coupling in CaCu3Sn4O12 probed by neutron diffraction. (United States)

    Kayser, P; Retuerto, M; Sánchez-Benítez, J; Martínez-Lope, M J; Fernández-Díaz, M T; Alonso, J A


    The A-site ordered perovskite oxide with the formula CaCu(3)Sn(4)O(12) has been synthesized in polycrystalline form under moderate pressure conditions (3.5 GPa) in combination with high temperature (1000 °C). This oxide crystallizes in the cubic space group [Formula: see text] (no. 204) with the unit-cell parameter a = 7.64535(6) Å at 300 K. The SnO(6) network is extremely tilted, giving rise to a square planar coordination for Cu(2+) cations. The non-magnetic character of Sn(4+) offers an excellent opportunity to probe the magnetism of Cu(2+) at the A sublattice in CaCu(3)Sn(4)O(12). Magnetic susceptibility shows that this compound is ferromagnetic below T(C) = 10 K, which is an unusual magnetic behaviour in cuprates. This peculiar aspect has been examined by neutron powder diffraction. The refinement of the magnetic structure at 4 K indeed indicates a parallel coupling between Cu(2+) spins with a magnetic moment of 0.5 μ(B)/Cu atom.

  19. Tube drawing technology for seamless pipes. Application to the Cu/Nb/Cu sandwiched pipes

    Energy Technology Data Exchange (ETDEWEB)

    Tsukada, Saburo; Ohnuki, Masao [Hitachi Cable, Ltd., Tsuchiura, Ibaraki (Japan); Fujino, Takeo; Saito, Kenji; Inoue, Hitoshi; Hitomi, Nobuteru; Yamazaki, Yoshishige [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan); Watanabe, Kakuji [Okuda Kinzoku Co. Ltd., Ota, Fukui (Japan)


    Tube drawing technology based on copper tubes at the Hitachi Cable Corporation was applied to manufacture Cu/Nb/Cu sandwiched seamless pipes for Nb/Cu clad superconducting RF cavities, which is being developed at KEK. This is the first application in our company. We met several problems but finally succeeded to fabricate 11 pipes needed to hydro-bulge forming for 1300 MHz single cell cavities. Here, we explain this technology and report the problems which happened during the manufacturing. (author)

  20. Structural Stabilities of Ordered Nb4 Clusters on the Cu(111) and Cu(100) Surfaces

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-Chun; ZHU Zi-Zhong


    @@ Based on first-principles calculations, we show that very high-density periodic arrays of Nb4 clusters with both the tetrahedron and quadrangle configurations can be stably absorbed on the Cu(111) and Cu(100) surfaces,with the quadrangle configurations more stable than the tetrahedron ones. The strong covalent bonding between atoms within the Nb4 clusters contributes to the stability of Nb4 adsorptions on the Cu surfaces.

  1. Task-specificity of balance training. (United States)

    Giboin, Louis-Solal; Gruber, Markus; Kramer, Andreas


    Despite much research on balance training, it is still unclear whether balance training leads to highly task-specific adaptations or rather non-specific adaptations. Hence, in this study we examined whether balance training increased performance only in the balance task that was trained or also in non-trained tasks. Forty healthy participants (28 m 12 f, 25 ± 4 years, 177 ± 10 cm, 73 ± 14 kg) were assigned to one of two training groups (TGs) or a control group. Both TGs completed six sessions over 2 weeks, only the training device differed. Before and after the training, performance in the trained task as well as in additional untrained tasks was recorded. ANOVAs showed that each TG outperformed the other groups only in the task they had trained (e.g., task trained by TG1: +225% in TG1, only +41% and +30% in TG2 and control, group*time interaction, pbalance training resulted in highly task-specific effects, no transfer even to very similar tasks was observed. Therefore, we recommend identifying and training exactly those tasks that need improvement, and test the efficacy of training programs using specific tests instead of general tests with limited functional relevance.

  2. Examining the Effect of Interference on Short-Term Memory Recall of Arabic Abstract and Concrete Words Using Free, Cued, and Serial Recall Paradigms (United States)

    Alduais, Ahmed Mohammed Saleh; Almukhaizeem, Yasir Saad


    Purpose: To see if there is a correlation between interference and short-term memory recall and to examine interference as a factor affecting memory recalling of Arabic and abstract words through free, cued, and serial recall tasks. Method: Four groups of undergraduates in King Saud University, Saudi Arabia participated in this study. The first…

  3. rTMS of medial parieto-occipital cortex interferes with attentional reorienting during attention and reaching tasks. (United States)

    Ciavarro, Marco; Ambrosini, Ettore; Tosoni, Annalisa; Committeri, Giorgia; Fattori, Patrizia; Galletti, Claudio


    Unexpected changes in the location of a target for an upcoming action require both attentional reorienting and motor planning update. In both macaque and human brain, the medial posterior parietal cortex is involved in both phenomena but its causal role is still unclear. Here we used on-line rTMS over the putative human V6A (pV6A), a reach-related region in the dorsal part of the anterior bank of the parieto-occipital sulcus, during an attention and a reaching task requiring covert shifts of attention and planning of reaching movements toward cued targets in space. We found that rTMS increased RTs to invalidly cued but not to validly cued targets during both the attention and reaching task. Furthermore, we found that rTMS induced a deviation of reaching endpoints toward visual fixation and that this deviation was larger for invalidly cued targets. The results suggest that reorienting signals are used by human pV6A area to rapidly update the current motor plan or the ongoing action when a behaviorally relevant object unexpectedly occurs in an unattended location. The current findings suggest a direct involvement of the action-related dorso-medial visual stream in attentional reorienting and a more specific role of pV6A area in the dynamic, on-line control of reaching actions.

  4. Cu2ZnSiS4

    Directory of Open Access Journals (Sweden)

    Kimberly A. Rosmus


    Full Text Available Single crystals of Cu2ZnSiS4, dicopper(I zinc silicon tetrasulfide, have been prepared via high-temperature solid-state synthesis. Cu2ZnSiS4 was found to have the wurtz-stannite structure type, like that of Li2CdGeS4, Li2CdSnS4, and Cu2CdSiS4. Each sulfur anion is tetrahedrally coordinated by two Cu cations, one Si cation, and one Zn cation, forming a three-dimensional honeycomb structure. When viewed along the c axis, the atoms are aligned in rows in which each cation alternates with the sulfur anions.

  5. Temperature stability of AgCu nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Sopoušek, Jiří, E-mail:; Zobač, Ondřej; Vykoukal, Vít [Masaryk University, Department of Chemistry, Faculty of Science (Czech Republic); Buršík, Jiří; Roupcová, Pavla [Institute of Physics of Materials ASCR (Czech Republic); Brož, Pavel; Pinkas, Jiří [Masaryk University, Department of Chemistry, Faculty of Science (Czech Republic); Vřešťál, Jan [Masaryk University, Central European Institute of Technology, CEITEC (Czech Republic)


    The colloidal solutions of the Ag–Cu nanoparticles (NPs, 10–32 nm) were prepared by solvothermal reactions. The samples of dried AgCu NPs and the resulting microstructures after heat treatment in air were investigated by various methods including electron microscopy (TEM, SEM) and high-temperature X-ray powder diffraction (HTXRD). The AgCu randomly mixed, Cu-rich, and Ag-rich face centred cubic crystal lattices were detected during the experiments. The temperature induced sintering was observed experimentally by HTXRD at 250 °C. The phase transformations at high temperatures were monitored by differential scanning calorimetry. The formation of the Ag-rich grains during heating in air and evolution of copper oxide microstructure were detected.Graphical abstract.

  6. W-WSi/sub 2/-Cu system

    Energy Technology Data Exchange (ETDEWEB)

    Efimov, Yu.V.; Frolova, T.M.; Bodak, O.I.; Kharchenko, O.I. (AN SSSR, Moscow. Inst. Metallurgii)


    Ternary system W-Si-Cu in the region up to 60 at.%(Si+Cu) has been investigated. Using the methods of metallographic and X-ray analyses of alloys in the system considered no new ternary compounds are detected. The major area of phase diagram of the ternary system studied is occupied by three-phase regions (W+W/sub 5/Si/sub 3/+..cap alpha..) and (W/sub 5/Si/sub 3/+WSi/sub 2/+..cap alpha..). Solid solution on copper basis (..cap alpha..-phase) occupies a narrow region, adjoining the system Cu-Si. Alloys, containing up to 3 at.%Si and 0.5 at.%Cu in cast and annealed states present solid solutions on tungsten basis. With the increase in silicon and copper content the second phase is separated.

  7. Effects of tensile stress on Cu clustering in irradiated Fe–Cu alloy

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, K., E-mail: [Institute of Nuclear Safety System, Inc., Mihama 919-1205 (Japan); Fukuya, K. [Institute of Nuclear Safety System, Inc., Mihama 919-1205 (Japan); Kasada, R.; Kimura, A. [Institute of Advanced Energy, Kyoto University, Uji 611-0011 (Japan); Ohkubo, T. [National Institute for Materials Science, Tsukuba 305-0047 (Japan)


    Effects of tensile stress on Cu clustering were explained using atom probe tomography (APT) results of Fe–0.6 wt.%Cu alloy specimens irradiated with 6.4 MeV Fe ions while applying a tensile stress of 60 MPa at room temperature (less than 50 °C) and 290 °C. The hardening under the tensile-stressed irradiation was smaller than that under the stress-free irradiation at both room temperature and 290 °C. APT results showed that well-defined Cu clusters were formed in all specimens even under the room temperature irradiation. The Cu clusters under the tensile-stressed condition were smaller and had higher densities than those under the stress-free condition. The lower Cu content in clusters and more diffuse Cu clustering were obtained for the specimens irradiated under the tensile-stressed condition. The hardening efficiency of Cu clusters was correlated with the Cu content in clusters and the coherency of interface between a cluster and the matrix. Application of tensile stress would control hardening by changing the nature of Cu clusters.

  8. Computer simulations of nanoindentation in Mg-Cu and Cu-Zr metallic glasses

    DEFF Research Database (Denmark)

    Paduraru, Anca; Andersen, Ulrik Grønbjerg; Thyssen, Anders


    The formation of shear bands during plastic deformation of Cu0.50Zr0.50 and Mg0.85Cu0.15 metallic glasses is studied using atomic-scale computer simulations. The atomic interactions are described using realistic many-body potentials within the effective medium theory, and are compared with similar...... simulations using a Lennard-Jones description of the material. The metallic glasses are deformed both in simple shear and in a simulated nanoindentation experiment. Plastic shear localizes into shear bands with a width of approximately 5 nm in CuZr and 8 nm in MgCu. In simple shear, the shear band formation...

  9. Enhanced Cu-to-Cu direct bonding by controlling surface physical properties (United States)

    Chiang, Po-Hao; Liang, Sin-Yong; Song, Jenn-Ming; Huang, Shang-Kun; Chiu, Ying-Ta; Hung, Chih-Pin


    Cu-to-Cu direct bonding is one of the key technologies for three-dimensional (3D) chip stacking. This research proposes a new concept to enhance Cu-to-Cu direct bonding through the control of surface physical properties. A linear relationship between bonding strength and the H/\\sqrt{R} value of the bonding face (H: subsurface hardness, R: surface roughness) was found. Low vacuum air plasma and thermal annealing were adopted to adjust the surface physical conditions. Instead of surface activation, an acceleration in copper atom diffusion due to plasma-induced compressive stress accounts for the improvement in bonding strength.

  10. Synthesis of MOF templated Cu/CuO@TiO2 nanocomposites for synergistic hydrogen production. (United States)

    Mondal, Indranil; Pal, Ujjwal


    A copper metal-organic framework (Cu-MOF) provides access to Cu/CuO@TiO2 hybrid nanocomposites with highly dispersive copper species adsorbed on a TiO2 semiconducting system. This novel nanostructure exhibits efficient hydrogen evolution performance under solar illumination of intensity ∼1 Sun. The rate of H2 production was systematically optimized under different operational parameters. Experimental observation reveals that mesoporous Cu/CuO@TiO2 nanocomposite with 0.5 wt% Cu loading showed the highest rate of H2 production (286 mmol g(-1) h(-1)), which is considerably higher than that of CuO loaded TiO2 prepared using a conventional impregnation method. This high photocatalytic H2 production activity is attributed predominantly to the presence of surface deposited Cu(0) species and the small size of the heterojunction (1-2 nm) between CuO and TiO2, which facilitate interfacial charge carrier transfer from the TiO2 nanoparticles. The catalyst showed good recyclability under prolonged exposure (30 h) to solar irradiation. Unlike many Pt decorated TiO2 photocatalysts, this hybrid photocatalyst provides an inexpensive means of harnessing solar energy.

  11. Electromigration in 3D-IC scale Cu/Sn/Cu solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Cheng-En, E-mail:; Lee, Pei-Tzu; Chen, Chih-Nan; Yang, Cheng-Hsien


    The electromigration effect on the three-dimensional integrated circuits (3D-IC) scale solder joints with a Cu/Sn(25–50 μm)/Cu configuration was investigated using a field-emission scanning electron microscope (FE–SEM) combined with electron backscatter diffraction (EBSD) analysis system. Electron current stressing for a few days caused the pronounced accumulation of Cu{sub 6}Sn{sub 5} in specific Sn grain boundaries (GBs). The EBSD analysis indicated that both the β-Sn crystallographic orientation and GB orientation play dominant roles in this accumulation. The dependencies of the Cu{sub 6}Sn{sub 5} accumulation on the two above factors (i.e., Sn grain orientation and GB orientation) can be well rationalized via a proposed mathematic model based on the Huntington and Grone's electromigration theory with the Cu anisotropic diffusion data in a β-Sn lattice. - Highlights: • Anisotropic Cu electromigration in the 3D-IC scale microelectronic solder joints. • Pronounced accumulation of Cu{sub 6}Sn{sub 5} intermetallic in specific Sn grain boundaries. • A linear dependence of Cu{sub 6}Sn{sub 5} accumulation over the current stressing time. • β-Sn and grain boundary orientations are the dominant factors in Cu{sub 6}Sn{sub 5} accumulation.

  12. On the importance of Task 1 and error performance measures in PRP dual-task studies

    Directory of Open Access Journals (Sweden)

    Tilo eStrobach


    Full Text Available The Psychological Refractory Period (PRP paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and 2 are presented with variable stimulus onset asynchronies (SOAs and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e. decreasing SOAs do not increase RTs and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/ or error rates in Task 1. This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects.

  13. Beta-decay of Cu-56

    NARCIS (Netherlands)

    Ramdhane, M; Baumann, P; Knipper, A; Walter, G; Janas, Z; Plochocki, A; Aysto, J; Dendooven, P; Jokinen, A; Oinonen, M; Pentila, H; Liu, W; Gorska, M; Grawe, H; Hu, Z; Kirchner, R; Klepper, O; Roeckl, E; Fujita, Y; Brown, BA


    By measuring positrons and P-delayed gamma-rays emitted from mass-separated sources, the decay of Cu-56 (4(+),T-z = -1,T = 1) to states in the doubly-magic nucleus Ni-56 was Studied for the first time. The half-life of Cu-56 was measured to be 78(15) ms, and four beta-delayed gamma-rays were assigne

  14. Errorless learning of prospective memory tasks: An experimental investigation in people with memory disorders (United States)

    Fish, Jessica E.; Manly, Tom; Kopelman, Michael D.; Morris, Robin G.


    The term prospective memory (PM) refers to memory for future intentions. PM problems are frequent in people with cognitive impairment and, because they are central to the realisation of many everyday goals, are important in rehabilitation. Event-based PM tasks (EBPM) are environmentally-cued and have primarily mnemonic demands, whereas time-based PM tasks (TBPM) require self-initiated retrieval, and have greater executive demands. Errorless learning (EL) is an encoding method that results in superior retrospective memory compared with “errorful” learning (EF). As this EL advantage (ELA) likely stems from its reduced explicit memory demands, and there is no such advantage for executive tasks, a greater ELA for EBPM than TBPM was predicted. Fourteen adults with neurological memory impairment completed PM tasks under four counterbalanced conditions: EL of EBPM, EL of TBPM, EF of EBPM, and EF of TBPM. A significant ELA was observed for EBPM (d = .63), but not TBPM (d = –.01). These results extend the evidence for EL within cognitive rehabilitation, by showing for the first time that the method can benefit future action in addition to retrospective memory. The clinical implications are also clear: errorless learning techniques may be usefully employed to support completion of day-to-day EBPM tasks. PMID:24894460

  15. Errorless learning of prospective memory tasks: An experimental investigation in people with memory disorders. (United States)

    Fish, Jessica E; Manly, Tom; Kopelman, Michael D; Morris, Robin G


    The term prospective memory (PM) refers to memory for future intentions. PM problems are frequent in people with cognitive impairment and, because they are central to the realisation of many everyday goals, are important in rehabilitation. Event-based PM tasks (EBPM) are environmentally-cued and have primarily mnemonic demands, whereas time-based PM tasks (TBPM) require self-initiated retrieval, and have greater executive demands. Errorless learning (EL) is an encoding method that results in superior retrospective memory compared with "errorful" learning (EF). As this EL advantage (ELA) likely stems from its reduced explicit memory demands, and there is no such advantage for executive tasks, a greater ELA for EBPM than TBPM was predicted. Fourteen adults with neurological memory impairment completed PM tasks under four counterbalanced conditions: EL of EBPM, EL of TBPM, EF of EBPM, and EF of TBPM. A significant ELA was observed for EBPM (d = .63), but not TBPM (d = -.01). These results extend the evidence for EL within cognitive rehabilitation, by showing for the first time that the method can benefit future action in addition to retrospective memory. The clinical implications are also clear: errorless learning techniques may be usefully employed to support completion of day-to-day EBPM tasks.

  16. V-Ge-Cu system

    Energy Technology Data Exchange (ETDEWEB)

    Savitskij, E.M.; Efimov, Yu.V.; Bodak, O.I.; Kharchenko, O.I.; Shomova, N.A.; Frolova, T.M.

    By the methods of microscopic, X-ray phase analyses, X-ray spectral microanalysis as well as by measurement of Tsub(C) and phase lattice parameters the structure of the vanadium-region of the V-Ge ternary system (up to 40 at.%) - Cu(up to 90 at.%) is studied and isothermal cross section at 800 deg C is plotted. In the studied region solid solutions on the base of vanadium, copper and V/sub 3/Ge and V/sub 5/Ge/sub 3/ compounds are in phase equilibria. The solid solution on the vanadium base in ternary alloys practically does not possess superconductivity at the temperature over 4.2 K. Tsub(C) of V/sub 3/Ge saturated with copper decreases up to 5.3-5.6 K depending on treatment conditions and alloys composition. The superspeed quenching from molten state and the consequent low-temperature tempering of ternary alloys can increase V/sub 3/Ge Tsub(C) up to 6-6.7 K.

  17. Dissolution and Interfacial Reactions of (Cu,Ni)6Sn5 Intermetallic Compound in Molten Sn-Cu-Ni Solders (United States)

    Wang, Chao-hong; Lai, Wei-han; Chen, Sinn-wen


    (Cu,Ni)6Sn5 is an important intermetallic compound (IMC) in lead-free Sn-Ag-Cu solder joints on Ni substrate. The formation, growth, and microstructural evolution of (Cu,Ni)6Sn5 are closely correlated with the concentrations of Cu and Ni in the solder. This study reports the interfacial behaviors of (Cu,Ni)6Sn5 IMC (Sn-31 at.%Cu-24 at.%Ni) with various Sn-Cu, Sn-Ni, and Sn-Cu-Ni solders at 250°C. The (Cu,Ni)6Sn5 substrate remained intact for Sn-0.7 wt.%Cu solder. When the Cu concentration was decreased to 0.3 wt.%, (Cu,Ni)6Sn5 significantly dissolved into the molten solder. Moreover, (Cu,Ni)6Sn5 dissolution and (Ni,Cu)3Sn4 formation occurred simultaneously for the Sn-0.1 wt.%Ni solder. In Sn-0.5 wt.%Cu-0.2 wt.%Ni solder, many tiny (Cu,Ni)6Sn5 particulates were formed and dispersed in the solder matrix, while in Sn-0.3 wt.%Cu-0.2 wt.%Ni a lot of (Ni,Cu)3Sn4 grains were produced. Based on the local equilibrium hypothesis, these results are further discussed based on the liquid-(Cu, Ni)6Sn5-(Ni,Cu)3Sn4 tie-triangle, and the liquid apex is suggested to be very close to Sn-0.4 wt.%Cu-0.2 wt.%Ni.

  18. Compression of klockmannite, CuSe (United States)

    Peiris, Suhithi M.; Pearson, Tania T.; Heinz, Dion L.


    Copper selenide (CuSe) was compressed in a diamond anvil cell at room temperature up to a pressure of 52 GPa and studied using energy dispersive x-ray diffraction and Raman spectroscopy. CuSe is nearly isostructural with copper sulfide (CuS), and a previous study indicates that copper sulfide undergoes reversible pressure-induced amorphization at 18 GPa. The intensity of the x-ray diffraction peaks for CuSe decrease slowly, however, they never completely disappear up to a pressure of 52 GPa. The third-order Birch-Murnaghan equation of state fit to the data yields K0=96.9±5.3 GPa and K0'=4.1±0.5. Vinet's universal equation of state yields essentially identical parameters. Raman spectroscopy demonstrates that upon compression, the S-S bond in CuS compresses differently than the Se-Se bond in CuSe, possibly accounting for the different high pressure behavior of these two very similar compounds.

  19. Antimicrobial Cu-bearing stainless steel scaffolds. (United States)

    Wang, Qiang; Ren, Ling; Li, Xiaopeng; Zhang, Shuyuan; Sercombe, Timothy B; Yang, Ke


    Copper-bearing stainless steel scaffolds with two different structures (Body Centered Cubic and Gyroid labyrinth) at two solid fractions (25% and 40%) were fabricated from both 316L powder and a mixture of 316L and elemental Cu powder using selective laser melting, and relative 316L scaffolds were served as control group. After processing, the antimicrobial testing demonstrated that the 316L-Cu scaffolds presented excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus, and the cell viability assay indicated that there was no cytotoxic effect of 316L-Cu scaffolds on rat marrow mesenchymal stem cells. As such, these have the potential to reduce implant-associated infections. The Cu was also found to homogeneously distribute within the microstructure by scanning electronic microcopy. The addition of Cu would not significantly affect its strength and stiffness compared to 316L scaffold, and the stiffness of all the scaffolds (3-20GPa) is similar to that of bone and much less than that of bulk stainless steel. Consequently, fabrication of such low stiffness porous structures, especially coupled with the addition of antimicrobial Cu, may provide a new direction for medical stainless steels.

  20. Spectroscopic study of Cu{sup 2+} and Cu{sup +} ions in high-transmission glass. Electronic structure and Cu{sup 2+}/Cu{sup +} concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Susana; Rodriguez, Fernando [MALTA-CONSOLIDER-Team, DCITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Urra, Inigo [Departmento Construccion, Area de Energia y medioambiente, CIDEMCO-Tecnalia, 20730 Azpeitia (Spain); Valiente, Rafael, E-mail: gomezss@unican.e [MALTA-CONSOLIDER-Team, Departmento Fisica Aplicada, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander (Spain)


    This work investigates the formation of photoluminescence centres in high-transmission glass (HTG) doped with Cu{sub 2}O and their capability to transform the solar spectrum by absorption/emission via Stokes-shifted PL into a more efficient spectrum for photovoltaic applications. Among the centres formed in HTG, both green photoluminescent Cu{sup +} and the non-photoluminescent Cu{sup 2+} centres are created but their relative concentration depends on the thermal treatment and the presence of other co-dopants. The measurement of the absorption coefficient {alpha}({lambda}) nearby the HTG optical gap for Cu{sup +} bands is accomplished by following the two-thickness method. This procedure allows us to obtain the actual absorption coefficient for the spectrum of each formed centre, from which we obtain the relative concentration of Cu{sup +}/Cu{sup 2+} as well as their absolute values. The analysis of the spectra provides information on the absorption cross sections, transition energies and bandwidths, the knowledge of which is essential to check the suitability of such centres for photovoltaic applications in solar cells.

  1. Task-focused modeling in automated agriculture (United States)

    Vriesenga, Mark R.; Peleg, K.; Sklansky, Jack


    Machine vision systems analyze image data to carry out automation tasks. Our interest is in machine vision systems that rely on models to achieve their designed task. When the model is interrogated from an a priori menu of questions, the model need not be complete. Instead, the machine vision system can use a partial model that contains a large amount of information in regions of interest and less information elsewhere. We propose an adaptive modeling scheme for machine vision, called task-focused modeling, which constructs a model having just sufficient detail to carry out the specified task. The model is detailed in regions of interest to the task and is less detailed elsewhere. This focusing effect saves time and reduces the computational effort expended by the machine vision system. We illustrate task-focused modeling by an example involving real-time micropropagation of plants in automated agriculture.

  2. Designing CALL Tasks for College English Learners

    Institute of Scientific and Technical Information of China (English)


    <正>As CALL(Computer Assisted Language Learning) became a new trend among China’s college English learners nowadays,it is time that teachers reflected on their teaching methodology innovation with the new technological advancement,one part of it is writing CALL tasks for their own individual classes.This paper presents a few basic principles and rationales of designing such tasks,and hope to work as a reminder for task writers.These principles and rationales include how to realize CLT(communicative language teaching) and learner-centredness and foster learner autonomy.In order to achieve this,it is reminded that task writers pay attention to a few points,like the communicativeness,contextualization,authenticity,and relatedness in task writing. Aspects of syllabus design,choice of texts,contents of activities and tasks and sequencing are put under investigation.

  3. Unnecessary work tasks and mental health

    DEFF Research Database (Denmark)

    Madsen, Ida E H; Tripathi, Manisha; Borritz, Marianne


    OBJECTIVES: According to the "stress-as-offense-to-self" perspective, work tasks that are considered unnecessary or unreasonable - so-called "illegitimate work tasks" - are likely to elicit stress-reactions. Previous studies, mostly cross-sectional, have shown that illegitimate tasks are associated...... with increased self-reported stress, cortisol, and counterproductive work behavior. In this article, we examine the prospective association between unnecessary work tasks, one type of illegitimate work tasks, and mental health among Danish human service workers. Further, we explore whether this association...... is modified by sex, age, occupational position, and baseline mental health status. METHODS: The data were obtained from self-administered questionnaires from 1351 Danish human service workers in three waves of data-collection during 1999-2005. We measured unnecessary work tasks by a single item, and assessed...

  4. On diffusion of Cu in ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Herklotz, F., E-mail: frank.herklotz@physik.tu-dresden.d [Institut fuer Angewandte Physik, Technische Universitaet Dresden, 01062 Dresden (Germany); Lavrov, E.V.; Weber, J. [Institut fuer Angewandte Physik, Technische Universitaet Dresden, 01062 Dresden (Germany)


    An experimental study of Cu diffusion in bulk ZnO single crystals in the temperature range 1012-1220 deg. C is presented. Concentration profiles of substitutional Cu were determined by IR absorption at 5817cm{sup -1}. Our findings reveal that Cu in ZnO diffuses faster than previously reported [G. Mueller, R. Helbig, J. Phys. Chem. Solids 32 (1971) 1971]. The discrepancy is tentatively explained by the formation of Cu complexes, which occurs at high Cu concentrations.

  5. The harder the task, the more inconsistent the performance: a PPT analysis on task difficulty. (United States)

    Rice, Stephen; Geels, Kasha; Hackett, Holly Raye; Trafimow, David; McCarley, Jason S; Schwark, Jeremy; Hunt, Gayle


    Previous research has demonstrated that as task difficulty increases, task performance subsequently decreases. These decrements in task performance as difficulty increases have been attributed to the processes individuals use to complete tasks. Over a series of three experiments, Potential Performance Theory (PPT; Trafimow & Rice, 2008 ; 2009), was used to test the hypothesis that decreases in task performance are, in part, due to inconsistency rather than only systematic factors. Task difficulty was manipulated in three visual search tasks by increasing set size (Experiment 1), decreasing contrast (Experiment 2), and increasing background distracters (Experiment 3). Findings over the three studies indicated that decreases in observed task performance as task difficulty increases are primarily due to a decrease of consistency rather than systematic factors. The theoretical implications of these findings are discussed.

  6. Semantic and phonological contributions to short-term repetition and long-term cued sentence recall. (United States)

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


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

  7. Examining variation in working memory capacity and retrieval in cued recall. (United States)

    Unsworth, Nash


    Two experiments examined the notion that individual differences in working memory capacity (WMC) are partially due to differences in search set size in cued recall. High and low WMC individuals performed variants of a cued recall task with either unrelated cue words (Experiment 1) or specific cue phrases (Experiment 2). Across both experiments low WMC individuals recalled fewer items, made more errors, and had longer correct recall latencies than high WMC individuals. Cross-experimental analyses suggested that providing participants with more specific cues decreased the size of the search set, leading to better recall overall. However, these effects were equivalent for high and low WMC. It is argued that these results are consistent with a search model framework in which low WMC individuals search through a larger set of items than high WMC individuals.

  8. Intellectual productivity under task ambient lighting



    A subjective experiment was conducted to evaluate intellectual productivity in three lighting conditions: (a) conventional ambient lighting, (b) task ambient lighting with normal colour temperature (5000 K), and (c) task ambient lighting with high colour temperature (6200 K). In the experiment, cognitive tasks were given to 24 participants. The concentration time ratio, which is a quantitative and objective evaluation index of the degree of concentration, was measured. The results showed that...

  9. Learning Multiple Tasks with Deep Relationship Networks


    Long, Mingsheng; Wang, Jianmin


    Deep neural networks trained on large-scale dataset can learn transferable features that promote learning multiple tasks for inductive transfer and labeling mitigation. As deep features eventually transition from general to specific along the network, a fundamental problem is how to exploit the relationship structure across different tasks while accounting for the feature transferability in the task-specific layers. In this work, we propose a novel Deep Relationship Network (DRN) architecture...

  10. Morphology, structure, and properties of Cu-poor and Cu-rich Cu(In,Ga)Se2 films partially selenized using H2Se gas (United States)

    Han, Anjun; Huang, Yongliang; Liu, Xiaohui; Xian, Wang; Meng, Fanying; Liu, Zhengxin


    Cu-poor and Cu-rich metallic precursors were prepared by cosputtering from In and Cu-Ga alloy targets and then partially selenized using H2Se gas. The properties of Cu(In,Ga)Se2 (CIGS) films are comparatively studied and the phase transition process is analyzed. The cosputtered metallic precursor has a rough morphology mostly covered by large In-rich nodules. After selenization, a large number of crumblike InSe grains were formed from the nodules on the surface of the Cu-rich film, whereas the Cu-poor film shows a dense surface. The selenized films comprise CIGS, Cu9(In,Ga)4 intermetallic, and the InSe phases. The proportion of the Cu9(In,Ga)4 phase in the Cu-rich film is more than that in the Cu-poor film. After annealing, the residual Cu9(In,Ga)4 of the Cu-poor film is eliminated. A negligible effect of Cu/(In+Ga) on the grain size can be observed. The CIGS solar cell with an efficiency of 15.1% was prepared by this method.

  11. Inhibiting the growth of Cu3Sn and Kirkendall voids in the Cu/Sn-Ag-Cu system by minor Pd alloying (United States)

    Ho, Cheng En; Kuo, Tsai Tung; Wang, Chun Chien; Wu, Wei Hsiang


    In this study, the metallurgical reaction between Cu substrates (electrolytic type) and a Sn3Ag0.5Cu-xPd alloy at 180°C was examined using a scanning electron microscope (SEM), electron probe microanalyzer (EPMA), focused ion beam (FIB) microscope, and transmission electron microscope (TEM). The results showed that the growth of Cu3Sn in the Cu/Sn-Ag-Cu solder joints was substantially suppressed by doping with a minor quantity of Pd (0.1-0.7 wt. %) in the solder alloy. The sluggish growth of Cu3Sn reduced the formation of Kirkendall voids at the Cu/Cu3Sn interface and significantly improved the mechanical reliability of the joint interface. It was argued that a minor addition of Pd into the solder stabilized the Cu6Sn5 phase and enlarged the interdiffusion coefficient of Cu6Sn5 but diminished that of the neighboring phase (Cu3Sn), thereby decreasing the Kirkendall effect in the Cu/Sn-Ag-Cu reactive system.

  12. Investigation of the Phase Equilibria of Sn-Cu-Au Ternary and Ag-Sn-Cu-Au Quaternary Systems and Interfacial Reactions in Sn-Cu/Au Couples (United States)

    Yen, Yee-Wen; Jao, Chien-Chung; Hsiao, Hsien-Ming; Lin, Chung-Yung; Lee, Chiapyng


    The phase equilibria of the Sn-Cu-Au ternary, Ag-Sn-Cu-Au quaternary systems and interfacial reactions between Sn-Cu alloys and Au were experimentally investigated at specific temperatures in this study. The experimental results indicated that there existed three ternary intermetallic compounds (IMCs) and a complete solid solubility between AuSn and Cu6Sn5 phases in the Sn-Cu-Au ternary system at 200°C. No quaternary IMC was found in the isoplethal section of the Ag-Sn-Cu-Au quaternary system. Three IMCs, AuSn, AuSn2, and AuSn4, were found in all couples. The same three IMCs and (Au,Cu)Sn/(Cu,Au)6Sn5 phases were found in all Sn-Cu/Au couples. The thickness of these reaction layers increased with increasing temperature and time. The mechanism of IMC growth can be described by using the parabolic law. In addition, when the reaction time was extended and the Cu content of the alloy was increased, the AuSn4 phase disappeared gradually. The (Au, Cu)Sn and (Cu,Au)6Sn5 layers played roles as diffusion barriers against Sn in Sn-Cu/Au reaction couple systems.

  13. The functional neuroanatomy of multitasking: combining dual tasking with a short term memory task. (United States)

    Deprez, Sabine; Vandenbulcke, Mathieu; Peeters, Ron; Emsell, Louise; Amant, Frederic; Sunaert, Stefan


    Insight into the neural architecture of multitasking is crucial when investigating the pathophysiology of multitasking deficits in clinical populations. Presently, little is known about how the brain combines dual-tasking with a concurrent short-term memory task, despite the relevance of this mental operation in daily life and the frequency of complaints related to this process, in disease. In this study we aimed to examine how the brain responds when a memory task is added to dual-tasking. Thirty-three right-handed healthy volunteers (20 females, mean age 39.9 ± 5.8) were examined with functional brain imaging (fMRI). The paradigm consisted of two cross-modal single tasks (a visual and auditory temporal same-different task with short delay), a dual-task combining both single tasks simultaneously and a multi-task condition, combining the dual-task with an additional short-term memory task (temporal same-different visual task with long delay). Dual-tasking compared to both individual visual and auditory single tasks activated a predominantly right-sided fronto-parietal network and the cerebellum. When adding the additional short-term memory task, a larger and more bilateral frontoparietal network was recruited. We found enhanced activity during multitasking in components of the network that were already involved in dual-tasking, suggesting increased working memory demands, as well as recruitment of multitask-specific components including areas that are likely to be involved in online holding of visual stimuli in short-term memory such as occipito-temporal cortex. These results confirm concurrent neural processing of a visual short-term memory task during dual-tasking and provide evidence for an effective fMRI multitasking paradigm. © 2013 Elsevier Ltd. All rights reserved.

  14. Formation processes of CuCl and regenerated Cu crystals on bronze surfaces in neutral and acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Wang Julin [Institute of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)]. E-mail:; Xu Chunchun [Institute of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Lv Guocheng [Institute of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)


    The paper is devoted to investigating the formation of CuCl and regenerated Cu crystals on bronze. Electrochemical behaviour of bronze in simulated anoxic edaphic media and occluded cell (O.C.) solutions was studied with cycle voltammetry (CV) and X-ray diffraction (XRD). Within potential range of -800 to +800 mV, oxidation occurred was largely a process in which Cu is oxidized to CuCl and the reduction process was a reverse of it. An atomic force microscopy (AFM) was used to observe the morphology of CuCl crystals, regenerated Cu crystals and corrosion interface at nm level. The deposition of regenerated Cu on simulated archaeological bronzes was simulated under experimental conditions for the first time. CuCl could be thoroughly reduced to pure Cu if reduction time interval were sufficiently prolonged. This provided a theoretical and experimental basis for getting rid of harmful CuCl patina from archaeological bronzes with electrochemical means.

  15. Analysis of Task-based Syllabus

    Institute of Scientific and Technical Information of China (English)



    Task-based language teaching is very popular in the modem English teaching.It is based on the Task-based Syllabus.Taskbased Syllabus focuses on the learners' communicative competence,which stresses learning by doing.From the theoretical assumption and definitions of the task,the paper analysizes the components of the task,then points out the merits and demerits of the syllabus.By this means the paper may give some tips to teachers and students when they use the tsk-based language teaching.

  16. Dynamic Task Allocation in Cooperative Robot Teams

    Directory of Open Access Journals (Sweden)

    Athanasios Tsalatsanis


    Full Text Available In this paper a dynamic task allocation and controller design methodology for cooperative robot teams is presented. Fuzzy logic based utility functions are derived to quantify each robot\\'s ability to perform a task. These utility functions are used to allocate tasks in real-time through a limited lookahead control methodology partially based on the basic principles of discrete event supervisory control theory. The proposed controller design methodology accommodates flexibility in task assignments, robot coordination, and tolerance to robot failures and repairs. Implementation details of the proposed methodology are demonstrated through a warehouse patrolling case study.

  17. Dynamic Task Allocation in Cooperative Robot Teams

    Directory of Open Access Journals (Sweden)

    Athanasios Tsalatsanis


    Full Text Available In this paper a dynamic task allocation and controller design methodology for cooperative robot teams is presented. Fuzzy logic based utility functions are derived to quantify each robot's ability to perform a task. These utility functions are used to allocate tasks in real-time through a limited lookahead control methodology partially based on the basic principles of discrete event supervisory control theory. The proposed controller design methodology accommodates flexibility in task assignments, robot coordination, and tolerance to robot failures and repairs. Implementation details of the proposed methodology are demonstrated through a warehouse patrolling case study.

  18. Task-oriented maximally entangled states

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, Pankaj; Pradhan, B, E-mail: agrawal@iopb.res.i, E-mail: bpradhan@iopb.res.i [Institute of Physics, Sachivalaya Marg, Bhubaneswar, Orissa 751 005 (India)


    We introduce the notion of a task-oriented maximally entangled state (TMES). This notion depends on the task for which a quantum state is used as the resource. TMESs are the states that can be used to carry out the task maximally. This concept may be more useful than that of a general maximally entangled state in the case of a multipartite system. We illustrate this idea by giving an operational definition of maximally entangled states on the basis of communication tasks of teleportation and superdense coding. We also give examples and a procedure to obtain such TMESs for n-qubit systems.

  19. Support for an auto-associative model of spoken cued recall: evidence from fMRI. (United States)

    de Zubicaray, Greig; McMahon, Katie; Eastburn, Mathew; Pringle, Alan J; Lorenz, Lina; Humphreys, Michael S


    Cued recall and item recognition are considered the standard episodic memory retrieval tasks. However, only the neural correlates of the latter have been studied in detail with fMRI. Using an event-related fMRI experimental design that permits spoken responses, we tested hypotheses from an auto-associative model of cued recall and item recognition [Chappell, M., & Humphreys, M. S. (1994). An auto-associative neural network for sparse representations: Analysis and application to models of recognition and cued recall. Psychological Review, 101, 103-128]. In brief, the model assumes that cues elicit a network of phonological short term memory (STM) and semantic long term memory (LTM) representations distributed throughout the neocortex as patterns of sparse activations. This information is transferred to the hippocampus which converges upon the item closest to a stored pattern and outputs a response. Word pairs were learned from a study list, with one member of the pair serving as the cue at test. Unstudied words were also intermingled at test in order to provide an analogue of yes/no recognition tasks. Compared to incorrectly rejected studied items (misses) and correctly rejected (CR) unstudied items, correctly recalled items (hits) elicited increased responses in the left hippocampus and neocortical regions including the left inferior prefrontal cortex (LIPC), left mid lateral temporal cortex and inferior parietal cortex, consistent with predictions from the model. This network was very similar to that observed in yes/no recognition studies, supporting proposals that cued recall and item recognition involve common rather than separate mechanisms.

  20. Some Reflections on Task-Based Language Performance Assessment. (United States)

    Bachman, Lyle F.


    Discusses problems in task-based language assessment, including the definition and sampling of tasks, generalizations across tasks, interpretations about broad ability and language use domains, and the notion of task difficulty. (Author/VWL)

  1. Magnetron sputtered Cu{sub 3}N/NiTiCu shape memory thin film heterostructures for MEMS applications

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Navjot; Choudhary, Nitin [Indian Institute of Technology Roorkee, Roorkee, Functional Nanomaterials Research Lab, Department of Physics and Centre of Nanotechnology (India); Goyal, Rajendra N. [Indian Institute of Technology, Roorkee, Department of Chemistry (India); Viladkar, S. [Indian Institute of Technology Roorkee, Roorkee, Functional Nanomaterials Research Lab, Department of Physics and Centre of Nanotechnology (India); Matai, I.; Gopinath, P. [Indian Institute of Technology, Roorkee, Centre for Nanotechnology (India); Chockalingam, S. [Indian Institute of Technology, Guwahati, Department of Biotechnology (India); Kaur, Davinder, E-mail: [Indian Institute of Technology Roorkee, Roorkee, Functional Nanomaterials Research Lab, Department of Physics and Centre of Nanotechnology (India)


    In the present study, for the first time, Cu{sub 3}N/NiTiCu/Si heterostructures were successfully grown using magnetron sputtering technique. Nanocrystalline copper nitride (Cu{sub 3}N with thickness {approx}200 nm) thin films and copper nanodots were subsequently deposited on the surface of 2-{mu}m-thick NiTiCu shape memory thin films in order to improve the surface corrosion and nickel release properties of NiTiCu thin films. Interestingly, the phase transformation from martensite phase to austenite phase has been observed in Cu{sub 3}N/NiTiCu heterostructures with corresponding change in texture and surface morphology of top Cu{sub 3}N films. Field emission scanning electron microscopy and atomic force microscope images of the heterostructures reveals the formation of 20-nm-sized copper nanodots on NiTiCu surface at higher deposition temperature (450 Degree-Sign C) of Cu{sub 3}N. Cu{sub 3}N passivated NiTiCu films possess low corrosion current density with higher corrosion potential and, therefore, better corrosion resistance as compared to pure NiTiCu films. The concentration of Ni released from the Cu{sub 3}N/NiTiCu samples was observed to be much less than that of pure NiTiCu film. It can be reduced to the factor of about one-ninth after the surface passivation resulting in smooth, homogeneous and highly corrosion resistant surface. The antibacterial and cytotoxicity of pure and Cu{sub 3}N coated NiTiCu thin films were investigated through green fluorescent protein expressing E. coli bacteria and human embryonic kidney cells. The results show the strong antibacterial property and non cytotoxicity of Cu{sub 3}N/NiTiCu heterostructure. This work is of immense technological importance due to variety of BioMEMS applications.


    Energy Technology Data Exchange (ETDEWEB)

    Fusselman, Steve


    Aerojet Rocketdyne (AR) has developed an innovative gasifier concept incorporating advanced technologies in ultra-dense phase dry feed system, rapid mix injector, and advanced component cooling to significantly improve gasifier performance, life, and cost compared to commercially available state-of-the-art systems. A key feature of the AR gasifier design is the transition from the gasifier outlet into the quench zone, where the raw syngas is cooled to ~ 400°C by injection and vaporization of atomized water. Earlier pilot plant testing revealed a propensity for the original gasifier outlet design to accumulate slag in the outlet, leading to erratic syngas flow from the outlet. Subsequent design modifications successfully resolved this issue in the pilot plant gasifier. In order to gain greater insight into the physical phenomena occurring within this zone, AR developed a cold flow simulation apparatus with Coanda Research & Development with a high degree of similitude to hot fire conditions with the pilot scale gasifier design, and capable of accommodating a scaled-down quench zone for a demonstration-scale gasifier. The objective of this task was to validate similitude of the cold flow simulation model by comparison of pilot-scale outlet design performance, and to assess demonstration scale gasifier design feasibility from testing of a scaled-down outlet design. Test results did exhibit a strong correspondence with the two pilot scale outlet designs, indicating credible similitude for the cold flow simulation device. Testing of the scaled-down outlet revealed important considerations in the design and operation of the demonstration scale gasifier, in particular pertaining to the relative momentum between the downcoming raw syngas and the sprayed quench water and associated impacts on flow patterns within the quench zone. This report describes key findings from the test program, including assessment of pilot plant configuration simulations relative to actual

  3. Drug and alcohol task force

    Energy Technology Data Exchange (ETDEWEB)

    Gordey, T. [ConocoPhillips Canada Resources Corp., Calgary, AB (Canada); Sunstrum, M. [Enform, Calgary, AB (Canada)


    Worker absenteeism due to substance abuse costs the Alberta economy approximately $720 million a year. It is estimated that 20 per cent of all drivers in fatal crashes were using alcohol, and the use of cannabis and cocaine in Alberta has more than doubled over the last 15 years. In addition, 1 in 10 Alberta workers have reported using alcohol while at work and 4 per cent have reported using alcohol 4 hours prior to coming to work during the previous 12 months. In an effort to ensure appropriate health and safety for workers in the Canadian petroleum industry, 6 trade associations in the sector have joined together as the Enform Alcohol and Drug Initiative and are now working to develop a common approach to drug and alcohol guidelines and workplace rules. The task group will determine if existing policies and guidelines are sufficient to ensure a safe workplace and will consider standardizing the testing, application and rehabilitation of workers with respect to the use of drugs and alcohol. In the past, disciplinary actions have often been reversed because employers have not been consistent or did not follow established alcohol and drug policies or test to specific standards. Various work rules for inappropriate alcohol and drug use were reviewed, as well as education and communication strategies regarding policy content. Standards for testing criteria were discussed, as well as issues concerning duty-to-accommodate circumstances. An excerpt of concentration standards was presented. It was concluded that a matrix for companies to assess and determine safety sensitive positions is needed. refs., tabs., figs.

  4. Synchronizing Parallel Tasks Using STM

    Directory of Open Access Journals (Sweden)

    Ryan Saptarshi Ray


    Full Text Available The past few years have marked the start of a historic transition from sequential to parallel computation. The necessity to write parallel programs is increasing as systems are getting more complex while processor speed increases are slowing down. Current parallel programming uses low-level programming constructs like threads and explicit synchronization using locks to coordinate thread execution. Parallel programs written with these constructs are difficult to design, program and debug. Also locks have many drawbacks which make them a suboptimal solution. One such drawback is that locks should be only used to enclose the critical section of the parallel-processing code. If locks are used to enclose the entire code then the performance of the code drastically decreases. Software Transactional Memory (STM is a promising new approach to programming shared-memory parallel processors. It is a concurrency control mechanism that is widely considered to be easier to use by programmers than locking. It allows portions of a program to execute in isolation, without regard to other, concurrently executing tasks. A programmer can reason about the correctness of code within a transaction and need not worry about complex interactions with other, concurrently executing parts of the program. If STM is used to enclose the entire code then the performance of the code is the same as that of the code in which STM is used to enclose the critical section only and is far better than code in which locks have been used to enclose the entire code. So STM is easier to use than locks as critical section does not need to be identified in case of STM. This paper shows the concept of writing code using Software Transactional Memory (STM and the performance comparison of codes using locks with those using STM. It also shows why the use of STM in parallel-processing code is better than the use of locks.

  5. Dynamics of task sets: evidence from dense-array event-related potentials. (United States)

    Poulsen, Catherine; Luu, Phan; Davey, Colin; Tucker, Don M


    Prior research suggests that task sets facilitate coherent, goal-directed behavior by providing an internal, contextual frame that biases selection toward context-relevant stimulus attributes and responses. Questions about how task sets are engaged, maintained, and shifted have recently become a major focus of research on executive control processes. We employed dense-array (128-channel) event-related potential (ERP) methodology to examine the dynamics of brain systems engaged during the preparation and implementation of task switching. The EEG was recorded while participants performed letter and digit judgments to pseudorandomly-ordered, univalent (#3, A%) and bivalent (G5) stimulus trials, with the appropriate task cued by a colored rectangle presented 450 ms before target onset. Results revealed spatial and temporal variations in brain activity that could be related to preparatory processes common to both switch and repeat trials, switch-specific control processes engaged to reconfigure and maintain task set under conflict, and visual priming benefits of task repetition. Despite extensive practice and improvement, both behavioral and ERP results indicated that subjects maintained high levels of executive control processing with extended task engagement. The patterns of ERP activity obtained in the present study fit well with functional neuroanatomical models of self-regulation of action. The frontopolar and right-lateralized frontal switch effects obtained in the present study are consistent with the role of these regions in adapting to changing contextual contingencies. In contrast, the centroparietal P3b and N384 effects related to the contextual ambiguity of bivalent trials are consistent with the context monitoring and updating functions associated with the posterior cingulate learning circuit.

  6. Hippocampus's role in forming "task-related" associations: Flashing to the things you are looking for

    Institute of Scientific and Technical Information of China (English)

    ZHANG XiuLing; NIKI Kazuhisa; LUO Jing


    Eichenbaum and colleagues observed that the same place did or did not activate the "goal-approach" cells in hippocampus depending on whether the place was the way for rata to approach specific goal.Parallel with this,the present neuroimage study revealed that,the same type of items could activate the hippocampus more when it was related to the task at hand than when it not.Participants were scanned by fMRI while they made judgments on the type of relationships contained in the word-pairs (e.g.,Does the word pair,"furniture-table",contain a "category-exemplar" relationship?).Event-related analysis revealed that the forming of "task-related" association activated hippocampus more than that of "task-unrelated",even if it was the same type of items,and,this hippocampsl difference was not caused by the different judgment requirements,nor by the effects of "yes" response.Consistently,the post-judgment cued-recall test exhibited a better retrieval performance for "task-related" associations than for the same type but "task-unrelated" associations.Results also showed that,the semantic re-latedness between the to-be-associated individual words (e.g.,the related word pair "healthy-hospital"versus the unrelated word pair "price-way") was not enough to activate the hippocampus when it was"task-unrelated".Generally,we proposed that,through participating in forming of "task-related" asso-ciations and consolidating of episodic memory,hippocampus enabled the organism to keep the in-formation that owned great survival values in mind for future usage.

  7. Parietal neural prosthetic control of a computer cursor in a graphical-user-interface task (United States)

    Revechkis, Boris; Aflalo, Tyson NS; Kellis, Spencer; Pouratian, Nader; Andersen, Richard A.


    Objective. To date, the majority of Brain-Machine Interfaces have been used to perform simple tasks with sequences of individual targets in otherwise blank environments. In this study we developed a more practical and clinically relevant task that approximated modern computers and graphical user interfaces (GUIs). This task could be problematic given the known sensitivity of areas typically used for BMIs to visual stimuli, eye movements, decision-making, and attentional control. Consequently, we sought to assess the effect of a complex, GUI-like task on the quality of neural decoding. Approach. A male rhesus macaque monkey was implanted with two 96-channel electrode arrays in area 5d of the superior parietal lobule. The animal was trained to perform a GUI-like ‘Face in a Crowd’ task on a computer screen that required selecting one cued, icon-like, face image from a group of alternatives (the ‘Crowd’) using a neurally controlled cursor. We assessed whether the crowd affected decodes of intended cursor movements by comparing it to a ‘Crowd Off’ condition in which only the matching target appeared without alternatives. We also examined if training a neural decoder with the Crowd On rather than Off had any effect on subsequent decode quality. Main results. Despite the additional demands of working with the Crowd On, the animal was able to robustly perform the task under Brain Control. The presence of the crowd did not itself affect decode quality. Training the decoder with the Crowd On relative to Off had no negative influence on subsequent decoding performance. Additionally, the subject was able to gaze around freely without influencing cursor position. Significance. Our results demonstrate that area 5d recordings can be used for decoding in a complex, GUI-like task with free gaze. Thus, this area is a promising source of signals for neural prosthetics that utilize computing devices with GUI interfaces, e.g. personal computers, mobile devices, and tablet

  8. Atomically engineering Cu/Ta interfaces.

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Edmund Blackburn, III (, Sandia National Laboratories, Albuquerque, NM); Zhou, Xiao Wang


    This report summarizes the major research and development accomplishments for the late start LDRD project (investment area: Enable Predictive Simulation) entitled 'Atomically Engineering Cu/Ta Interfaces'. Two ultimate goals of the project are: (a) use atomistic simulation to explore important atomistic assembly mechanisms during growth of Cu/Ta multilayers; and (b) develop a non-continuum model that has sufficient fidelity and computational efficiency for use as a design tool. Chapters 2 and 3 are essentially two papers that address respectively these two goals. In chapter 2, molecular dynamics simulations were used to study the growth of Cu films on (010) bcc Ta and Cu{sub x}Ta{sub 1-x} alloy films on (111) fcc Cu. The results indicated that fcc crystalline Cu films with a (111) texture are always formed when Cu is grown on Ta. The Cu films are always polycrystalline even when the Ta substrate is single crystalline. These polycrystalline films are composed of grains with only two different orientations, which are separated by either orientational grain boundaries or misfit dislocations. Periodic misfit dislocations and stacking fault bands are observed. The Cu film surface roughness was found to decrease with increasing adatom energy. Due to a Cu surface segregation effect, the Cu{sub x}Ta{sub 1-x} films deposited on Cu always have a higher Cu composition than that used in the vapor mixture. When Cu and Ta compositions in the films are comparable, amorphous structures may form. The fundamental origins for all these phenomena have been studied in terms of crystallography and interatomic interactions. In chapter 3, a simplified computational method, diffusional Monte Carlo (dMC) method, was developed to address long time kinetic processes of materials. Long time kinetic processes usually involve material transport by diffusion. The corresponding microstructural evolution of materials can be analyzed by kinetic Monte Carlo simulation methods, which

  9. First-principles study of defect formation in the photovoltaic semiconductors Cu2GeS3 and Cu2ZnGeS4 for comparison with Cu2SnS3, Cu2ZnSnS4, and CuInSe2 (United States)

    Nishihara, Hironori; Maeda, Tsuyoshi; Shigemi, Akio; Wada, Takahiro


    The formation energies of neutral Cu, Ge, and S vacancies in monoclinic Cu2GeS3 and those of neutral Cu, Zn, Ge, and S vacancies in kesterite-type Cu2ZnGeS4 were evaluated by first-principles pseudopotential calculations using plane-wave basis functions. The calculations were performed at typical points in a schematic ternary phase diagram of a Cu-Ge-S system for Cu2GeS3 and in Cu-(Zn1/2Ge1/2)-S and Cu29S16-ZnS-GeS2 pseudoternary phase diagrams for Cu2ZnGeS4. The results have been compared with those for Cu2SnS3, Cu2ZnSnS4, and CuInSe2 calculated with the same version of the CASTEP program code. The results indicate that Cu vacancies are easily formed in Cu2GeS3 and Cu2ZnGeS4 under the Cu-poor condition as in the cases of Cu2SnS3, Cu2ZnSnS4, and CuInSe2, suggesting that Cu2GeS3 and Cu2ZnGeS4 are also preferable p-type absorber materials for thin-film solar cells. Desirable preparation conditions of these thin films for photovoltaic application are discussed using the calculated formation energies of antisite defects.

  10. Dynamics of the central bottleneck: dual-task and task uncertainty.

    Directory of Open Access Journals (Sweden)

    Mariano Sigman


    Full Text Available Why is the human brain fundamentally limited when attempting to execute two tasks at the same time or in close succession? Two classical paradigms, psychological refractory period (PRP and task switching, have independently approached this issue, making significant advances in our understanding of the architecture of cognition. Yet, there is an apparent contradiction between the conclusions derived from these two paradigms. The PRP paradigm, on the one hand, suggests that the simultaneous execution of two tasks is limited solely by a passive structural bottleneck in which the tasks are executed on a first-come, first-served basis. The task-switching paradigm, on the other hand, argues that switching back and forth between task configurations must be actively controlled by a central executive system (the system controlling voluntary, planned, and flexible action. Here we have explicitly designed an experiment mixing the essential ingredients of both paradigms: task uncertainty and task simultaneity. In addition to a central bottleneck, we obtain evidence for active processes of task setting (planning of the appropriate sequence of actions and task disengaging (suppression of the plan set for the first task in order to proceed with the next one. Our results clarify the chronometric relations between these central components of dual-task processing, and in particular whether they operate serially or in parallel. On this basis, we propose a hierarchical model of cognitive architecture that provides a synthesis of task-switching and PRP paradigms.

  11. The shielding function of task rules in the context of task switching. (United States)

    Reisenauer, Renate; Dreisbach, Gesine


    There is increasing evidence that task rules help shield the response against distractor interference. Here, the authors investigate the cognitive mechanisms underlying this assumed shielding function of task rules and how it is adjusted to changing task demands. In two experiments, participants switched between a noun categorization and an adjective categorization task. Target words were superimposed on distractor pictures. These pictures were always irrelevant and depicted either objects also used as target words in the noun task (noun distractors) or objects that were not part of the noun target-set but could be categorized according to the noun task (noun-related distractors). Results show that (a) on task repetitions shielding prevents interference from any distractors associated with a competing task; this is indicated by the lack of interference on adjective task repetitions; and (b) shielding is reduced on task switches. In the noun task, this reduction resulted in attenuated interference by noun-related distractors. In the adjective task, spatial distractors did not interfere despite the reduction. This result suggests that shielding is supported by a processing advantage for task-related information and not by distractor suppression.


    Sarker, Abeed; Nikfarjam, Azadeh; Gonzalez, Graciela


    Social media has evolved into a crucial resource for obtaining large volumes of real-time information. The promise of social media has been realized by the public health domain, and recent research has addressed some important challenges in that domain by utilizing social media data. Tasks such as monitoring flu trends, viral disease outbreaks, medication abuse, and adverse drug reactions are some examples of studies where data from social media have been exploited. The focus of this workshop is to explore solutions to three important natural language processing challenges for domain-specific social media text: (i) text classification, (ii) information extraction, and (iii) concept normalization. To explore different approaches to solving these problems on social media data, we designed a shared task which was open to participants globally. We designed three tasks using our in-house annotated Twitter data on adverse drug reactions. Task 1 involved automatic classification of adverse drug reaction assertive user posts; Task 2 focused on extracting specific adverse drug reaction mentions from user posts; and Task 3, which was slightly ill-defined due to the complex nature of the problem, involved normalizing user mentions of adverse drug reactions to standardized concept IDs. A total of 11 teams participated, and a total of 24 (18 for Task 1, and 6 for Task 2) system runs were submitted. Following the evaluation of the systems, and an assessment of their innovation/novelty, we accepted 7 descriptive manuscripts for publication--5 for Task 1 and 2 for Task 2. We provide descriptions of the tasks, data, and participating systems in this paper.

  13. Different neuroplasticity for task targets and distractors.

    Directory of Open Access Journals (Sweden)

    Elsie Y Spingath

    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

  14. Different neuroplasticity for task targets and distractors. (United States)

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


    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

  15. Novel CuCr2O4 embedded CuO nanocomposites for efficient photodegradation of organic dyes (United States)

    Mageshwari, K.; Sathyamoorthy, R.; Lee, Jeong Yong; Park, Jinsub


    Novel photocatalyst based on CuO-CuCr2O4 nanocomposites was synthesized for different Cr3+ concentration by reflux condensation method, and their photocatalytic activity was evaluated by monitoring the photodegradation of methyl orange (MO) and methylene blue dyes (MB) under UV light irradiation. Phase evolution by X-ray diffraction showed monoclinic CuO and tetragonal CuCr2O4 as the components of the prepared nanocomposites. Morphological analysis by scanning electron microscope and transmission electron microscope revealed that the incorporation of Cr3+ in CuO lattice alters the morphology of CuO from microsphere to cluster shape. Photoluminescence spectra of CuO-CuCr2O4 nanocomposites exhibited reduced PL emissions compared to pure CuO, indicating the low recombination rate of photogenerated electrons and holes. As expected, the CuCr2O4 loaded CuO showed enhanced photocatalytic activity for MO and MB dyes, and the kinetic studies suggest that the degradation follows pseudo-first-order kinetics. The enhanced photocatalytic activity of CuO-CuCr2O4 nanocomposites can be attributed to the presence of CuCr2O4 as an electron acceptor, which improves the effective charge separation in CuO.

  16. One-pot synthesis of hierarchical Cu2O/Cu hollow microspheres with enhanced visible-light photocatalytic activity (United States)

    Hong, Tianjie; Tao, Feifei; Lin, Jiudong; Ding, Wei; Lan, Mingxuan


    The hierarchical Cu2O/Cu hollow microspheres have been fabricated by the one-pot solvothermal redox method, which is one-step approach without any surfactant and template. By using the HRTEM, XRD, XPS and UV-vis spectroscopy, the as-prepared product is composed of Cu2O and Cu with energy band gap of 1.72 eV. Based on the time-dependent experiments, the content of Cu2O and Cu compositions can be effectively controlled by adjusting the reaction time and a possible mechanism is proposed. In addition, using various dye molecules to stimulate pollutants, the hierarchical Cu2O/Cu hollow microspheres reacted for 8 h exhibit excellent visible-light photocatalytic activities, which is much higher than those of the Cu2O/Cu catalysts formed at the shorter reaction time, commercial Cu2O powder and the mixture of alone Cu2O and Cu. This enhanced photocatalytic performance makes these hierarchical Cu2O/Cu hollow microspheres a kind of efficient visible-light photocatalyst in removing some organic compounds in wastewater.

  17. On Cu(II) Cu(II) distance measurements using pulsed electron electron double resonance (United States)

    Yang, Zhongyu; Becker, James; Saxena, Sunil


    The effects of orientational selectivity on the 4-pulse electron electron double resonance (PELDOR) ESR spectra of coupled Cu(II)-Cu(II) spins are presented. The data were collected at four magnetic fields on a poly-proline peptide containing two Cu(II) centers. The Cu(II)-PELDOR spectra of this peptide do not change appreciably with magnetic field at X-band. The data were analyzed by adapting the theory of Maryasov, Tsvetkov, and Raap [A.G. Maryasov, Y.D. Tsvetkov, J. Raap, Weakly coupled radical pairs in solids:ELDOR in ESE structure studies, Appl. Magn. Reson. 14 (1998) 101-113]. Simulations indicate that orientational effects are important for Cu(II)-PELDOR. Based on simulations, the field-independence of the PELDOR data for this peptide is likely due to two effects. First, for this peptide, the Cu(II) g-tensor(s) are in a very specific orientation with respect to the interspin vector. Second, the flexibility of the peptide washes out the orientation effects. These effects reduce the suitability of the poly-proline based peptide as a good model system to experimentally probe orientational effects in such experiments. An average Cu(II)-Cu(II) distance of 2.1-2.2 nm was determined, which is consistent with earlier double quantum coherence ESR results.

  18. Synthesis and photocatalytic activity of carbon spheres loaded Cu{sub 2}O/Cu composites

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yinhui, E-mail:; Zhao, Mengyao; Zhang, Na; Li, Ruijuan; Chen, Jianxin


    Highlights: • Carbon spheres loaded Cu{sub 2}O/Cu composites are obtained by hydrothermal process. • Cu{sub 2}O/Cu nanocrystals grow on the surface of carbon spheres. • The composites with core–shell structure show highly photo-catalytic activity. • The composites can degrade methyl orange under simulated solar light irradiation. • The composites can be used to treat dye wastewater or organic pollutants. - Abstract: In this work, using amylose as carbon source and cupric acetate as copper source, carbon spheres loaded Cu{sub 2}O/Cu composites were obtained by hydrothermal synthesis. The effects of the molar ratios between glucose and Cu(II), and hydrothermal time on the morphology and sizes of the composites were investigated. The result of photocatalytic experiments demonstrated that the composites could degrade methyl orange in aqueous solution under simulated solar light irradiation. The highest degradation rate was achieved to 93.83% when the composites were prepared by hydrothermal synthesis at 180 °C for 16 h and the molar ratio between glucose and Cu(II) was 10/1. The composites, as new and promising materials, can be used to treat dye wastewater or other organic pollutants.

  19. Carbon Supported Oxide-Rich Pd-Cu Bimetallic Electrocatalysts for Ethanol Electrooxidation in Alkaline Media Enhanced by Cu/CuOx

    Directory of Open Access Journals (Sweden)

    Zengfeng Guo


    Full Text Available Different proportions of oxide-rich PdCu/C nanoparticle catalysts were prepared by the NaBH4 reduction method, and their compositions were tuned by the molar ratios of the metal precursors. Among them, oxide-rich Pd0.9Cu0.1/C (Pd:Cu = 9:1, metal atomic ratio exhibits the highest electrocatalytic activity for ethanol oxidation reaction (EOR in alkaline media. X-ray photoelectron spectroscopy (XPS and high resolution transmission electron microscopy (HRTEM confirmed the existence of both Cu and CuOx in the as-prepared Pd0.9Cu0.1/C. About 74% of the Cu atoms are in their oxide form (CuO or Cu2O. Besides the synergistic effect of Cu, CuOx existed in the Pd-Cu bimetallic nanoparticles works as a promoter for the EOR. The decreased Pd 3d electron density disclosed by XPS is ascribed to the formation of CuOx and the spill-over of oxygen-containing species from CuOx to Pd. The low Pd 3d electron density will decrease the adsorption of CH3COads intermediates. As a result, the electrocatalytic activity is enhanced. The onset potential of oxide-rich Pd0.9Cu0.1/C is negative shifted 150 mV compared to Pd/C. The oxide-rich Pd0.9Cu0.1/C also exhibited high stability, which indicated that it is a candidate for the anode of direct ethanol fuel cells (DEFCs.

  20. Altered activity of the medial prefrontal cortex and amygdala during acquisition and extinction of an active avoidance task

    Directory of Open Access Journals (Sweden)

    Xilu eJiao


    Full Text Available Altered medial prefrontal cortex (mPFC and amygdala function is associated with anxiety-related disorders. While the mPFC-amygdala pathway has a clear role in fear conditioning, these structures are also involved in active avoidance. Given that avoidance perseveration represents a core symptom of anxiety disorders, the neural substrate of avoidance, especially its extinction, requires better understanding. The present study was designed to investigate the activity of mPFC and amygdala neurons during acquisition and extinction of lever-press avoidance in rats. In particular, neural activity was examined in the mPFC, intercalated cell clusters (ITCs, lateral (LA, basal (BA and central (CeA amygdala, at various time points during acquisition and extinction, using induction of the immediate early gene product, c-Fos. Neural activity was greater in the mPFC, LA, BA, and ITC during the extinction phase as compared to the acquisition phase. In contrast, the CeA was the only region that was more activated during acquisition than during extinction. Our results indicate that elevated activity in the mPFC, BA, LA and ITCs, and reduced CeA activity is associated with extinction of active avoidance. Moreover, inhibitory neurons are activated differently in the mPFC and BA during early and late phase of acquisition and extinction, suggesting their dynamic involvement in the development of avoidance response. Together, these data start to identify the key brain regions important in active avoidance behavior, areas that could be associated with avoidance perseveration in anxiety disorders.

  1. Control and Interference in Task Switching--A Review (United States)

    Kiesel, Andrea; Steinhauser, Marco; Wendt, Mike; Falkenstein, Michael; Jost, Kerstin; Philipp, Andrea M.; Koch, Iring


    The task-switching paradigm offers enormous possibilities to study cognitive control as well as task interference. The current review provides an overview of recent research on both topics. First, we review different experimental approaches to task switching, such as comparing mixed-task blocks with single-task blocks, predictable task-switching…

  2. Molecular switching analyzed with sub-molecular precision: CuPc on Cu(111)

    Energy Technology Data Exchange (ETDEWEB)

    Schaffert, Johannes; Cottin, Maren; Sonntag, Andreas; Karacuban, Hatice; Bobisch, Christian; Moeller, Rolf [Faculty of Physics, Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, 47048 Duisburg (Germany); Lorente, Nicolas [Centro de Investigacion en Nanociencia y Nanotecnologia, Campus de la Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain)


    The current fluctuations in Scanning Tunneling Microscopy and Spectroscopy have been analyzed in real time using special analogue electronics. This type of Scanning Action Microscopy technique allows to map topography and switching processes simultaneously. For the Cu-Phthalocyanine (CuPc) molecule on Cu(111), switching between two states is observed. The switching frequency, the switching amplitude and the ratio between the residence times in the observed states can be studied with Angstrom spacial resolution. Spectroscopic data obtained at 7 K yields information about the involved electronic states. Based on the experimental data as well as DFT calculations a model is presented. The CuPc molecule switches between different adsorption configurations, which are attributed to different angles of molecular rotation on the Cu(111) surface.

  3. Study of the /sup 63/Cu(n,. gamma. )/sup 64/Cu reaction

    Energy Technology Data Exchange (ETDEWEB)

    Delfini, M.G.; Kopecky, J.; de Haas, J.B.M.; Liou, H.I.; Chrien, R.E.; Endt, P.M.


    The ..gamma..-radiation resulting from the capture of unpolarized thermal, 2 and 24 keV neutrons in enriched /sup 63/Cu, and of polarized thermal neutrons in /sup 63/Cu oriented at low temperature has been investigated. Of the 323 ..gamma..-rays observed 299 could be placed in a /sup 64/Cu level scheme containing 109 levels. The reaction Q-value amounts to 7916.09(12) keV. The Z/sup 2/ analysis of the ..gamma..-ray angular distributions obtained from capture of polarized neutrons in oriented /sup 63/Cu resulted in three unambiguous spin assignments for levels in /sup 64/Cu. The fraction of the Jsup(..pi..) = 1/sup -/ channel in the thermal capture was determined as (94 +- 2)%. For one level an unambiguous spin assignment has been obtained from the decay scheme.


    Institute of Scientific and Technical Information of China (English)

    李勋平; 周敏波; 夏建民; 马骁; 张新平


    研究了焊盘材料界面耦合作用对Cu(Ni)/Sn-3.0Ag-0.5Cu/Cu(Ni)BGA(Ball Grid Array)结构焊点焊后态和125℃等温时效过程中界面金属间化合物(IMC)的成分、形貌和生长动力学的影响.结果表明,凸点下金属层(UBM)Ni界面IMC的成分与钎料中Cu含量有关,钎料中Cu含量较高时界面IMC为(Cu,Ni)6Sn5,而Cu含量较低时,则生成(Cu,Ni)3Sn4;Cu-Ni耦合易导致Cu/Sn-3.0Ag-0.5Cu/Ni焊点中钎料/Ni界面IMC异常生长并产生剥离而进入钎料.125℃等温时效过程中,Sn-3.0Ag-0.5Cu/Cu界面IMC的生长速率常数随钎料中Cu含量增加而提高,Cu-Cu耦合降低一次回流侧IMC生长速率常数;Cu-Ni耦合和Ni-Ni耦合均导致焊点一次回流Ni侧界面IMC的生长速率常数增大,但Ni对界面IMC生长动力学的影响大于Cu;Ni有利于抑制Cu界面Cu3Sn生长,降低界面IMC生长速率,但Cu-Ni耦合对Cu界面Cu3Sn中Kirkendall空洞率无明显影响.%The formation and evolution of interfacial intermetallic compounds (IMCs) in Cu(Ni)/Sn-3.0Ag-0.5Cu/Cu(Ni) BGA (Ball Grid Array) structure solder joints both in the asreflowed state and undergoing isothermal aging at 125 C were investigated. The results show that there exists a significant cross-interaction effect of the solder pad/under bump metal (UBM) on the composition, morphology and growth kinetics of interfacial IMCs in solder joints. The reactions of solder/Ni UBM strongly depends on the Cu content of the solder, for a high Cu content, a continuous (Cu, Ni)6Sn5 layer forms at the interface, while for a low Cu content, a continuous (Ni, Cu)3Sn4 layer appears at the interface. The cross-interaction of Cu and Ni in Cu/Sn-3.0Ag-0.5Cu(SAC)/Ni solder joints has obvious influence on the composition and morphology of the interfacial IMC; and the IMC spalling phenomenon occurs at the interface of Ni side. During isothermal aging at 125 ℃, the growth rate constant of the interfacial IMC layer in SAC/Cu and Cu/SAC/Cu joints increases with

  5. Investigation on the Microstructure, Interfacial IMC Layer, and Mechanical Properties of Cu/Sn-0.7Cu- xNi/Cu Solder Joints (United States)

    Yang, Li; Ge, Jinguo; Zhang, Yaocheng; Dai, Jun; Liu, Haixiang; Xiang, Jicen


    Sn-0.7Cu- xNi composite solder has been fabricated via mechanical mixing of different weight percentages of Ni particles with Sn-0.7Cu solder paste, and the effect of the Ni concentration on the microstructure, wettability, and tensile properties of Cu/Sn-0.7Cu- xNi/Cu solder joints investigated. The results show that refined dot-shaped particles of intermetallic compounds (IMCs) are uniformly dispersed in a primary β-Sn matrix in the Cu/Sn-0.7Cu-(0.05-0.1)Ni/Cu solder joints. The interfacial IMC layer thickness increased slightly when adding Ni content to 0.05 wt.%, then rapidly when further increasing the Ni concentration to 0.4 wt.%. Excellent wettability with bright appearance was obtained for the Sn-0.7Cu-0.05Ni solder due to diminished interfacial tension. The tensile properties improved after adding Ni content to 0.05 wt.% due to the presence of the refined dot-like IMC particles, in agreement with theoretical predictions based on the combination of dispersion and grain-refinement strengthening mechanisms. Refined microstructure and enhanced mechanical properties were obtained for the Cu/Sn-0.7Cu-0.05Ni/Cu solder joint.

  6. SemEval-2016 task 10

    DEFF Research Database (Denmark)

    Schneider, Nathan; Hovy, Dirk; Johannsen, Anders Trærup


    This task combines the labeling of multiword expressions and supersenses (coarse-grained classes) in an explicit, yet broad-coverage paradigm for lexical semantics. Nine systems participated; the best scored 57.7% F1 in a multi-domain evaluation setting, indicating that the task remains largely u...

  7. Metacognition in Monkeys during an Oculomotor Task (United States)

    Middlebrooks, Paul G.; Sommer, Marc A.


    This study investigated whether rhesus monkeys show evidence of metacognition in a reduced, visual oculomotor task that is particularly suitable for use in fMRI and electrophysiology. The 2-stage task involved punctate visual stimulation and saccadic eye movement responses. In each trial, monkeys made a decision and then made a bet. To earn…

  8. First Workshop on Supporting Complex Search Tasks

    NARCIS (Netherlands)

    Gäde, M.; Hall, M.; Huurdeman, H.; Kamps, J.; Koolen, M.; Skov, M.; Toms, E.; Walsh, D.


    There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks, is fragmente

  9. Students' Views of Example Generation Tasks (United States)

    Breen, Sinead; O'Shea, Ann; Pfeiffer, Kirsten


    We report here on students' views of example generation tasks assigned to them in two first year undergraduate Calculus courses. The design and use of such tasks was undertaken as part of a project which aimed to afford students opportunities to develop their thinking skills and their conceptual understanding. In interviews with 10 students, we…

  10. Instructional Objectives: Selecting and Devising Tasks (United States)

    Mileff, Milo


    In the present paper and the discussion that follows, the author presents aspects of test construction and a careful description of instructional objectives. Constructing tests involves several stages such as describing language objectives, selecting appropriate test task, devising and assembling test tasks, and devising a scoring system for…

  11. Antiphospholipid Syndrome Clinical Research Task Force Report

    NARCIS (Netherlands)

    Erkan, D.; Derksen, R.; Levy, R.; Machin, S.; Ortel, T.; Pierangeli, S.; Roubey, R.; Lockshin, M.


    The Antiphospholipid Syndrome (APS) Clinical Research Task Force (CRTF) was one of six Task Forces developed by the 13(th) International Congress on Antiphospholipid Antibodies (aPL) organization committee with the purpose of: a) evaluating the limitations of APS clinical research and developing gui

  12. Task based synthesis of serial manipulators

    Directory of Open Access Journals (Sweden)

    Sarosh Patel


    Full Text Available Computing the optimal geometric structure of manipulators is one of the most intricate problems in contemporary robot kinematics. Robotic manipulators are designed and built to perform certain predetermined tasks. There is a very close relationship between the structure of the manipulator and its kinematic performance. It is therefore important to incorporate such task requirements during the design and synthesis of the robotic manipulators. Such task requirements and performance constraints can be specified in terms of the required end-effector positions, orientations and velocities along the task trajectory. In this work, we present a comprehensive method to develop the optimal geometric structure (DH parameters of a non-redundant six degree of freedom serial manipulator from task descriptions. In this work we define, develop and test a methodology to design optimal manipulator configurations based on task descriptions. This methodology is devised to investigate all possible manipulator configurations that can satisfy the task performance requirements under imposed joint constraints. Out of all the possible structures, the structures that can reach all the task points with the required orientations are selected. Next, these candidate structures are tested to see whether they can attain end-effector velocities in arbitrary directions within the user defined joint constraints, so that they can deliver the best kinematic performance. Additionally least power consuming configurations are also identified.

  13. Workplace for analysis of task performance

    NARCIS (Netherlands)

    Bos, J; Mulder, LJM; van Ouwerkerk, RJ; Maarse, FJ; Akkerman, AE; Brand, AN; Mulder, LJM


    In current research on mental workload and task performance a large gap exists between laboratory based studies and research projects in real life working practice. Tasks conducted within a laboratory environment often lack a strong resemblance with real life working situations. This paper presents

  14. Health Occupations. Education for Employment Task Lists. (United States)

    Lake County Area Vocational Center, Grayslake, IL.

    The duties and tasks found in these task lists form the basis of instructional content for secondary, postsecondary, and adult occupational training programs for health occupations. The health occupations are divided into five clusters. The clusters and occupations are: health occupations, nursing occupations (home health aide, geriatric aide,…

  15. Challenging experiences: gender differences in task choice

    NARCIS (Netherlands)

    de Pater, I.E.; van Vianen, A.E.M.; Fischer, A.H.; van Ginkel, W.P.


    Purpose - The purpose of this paper is to examine: gender differences in the choice to perform challenging tasks, gender differences in the actual performance of challenging tasks, and the impact of challenging experiences on supervisors' evaluations of individuals' potential for career advancement.

  16. Integrative views on dual-task costs

    NARCIS (Netherlands)

    Band, Guido P. H.; Jolicœur, Pierre; Akyürek, Elkan G.; Memelink, Jiska


    In this paper, we introduce a special issue about unique and shared mechanisms underlying the performance limitations observed in dual tasks. In particular, the relationship between task-switching costs, the attentional-blink effect, and the psychological refractory period effect is reviewed. These

  17. A Bilingual Advantage in Task Switching (United States)

    Prior, Anat; MacWhinney, Brian


    This study investigated the possibility that lifelong bilingualism may lead to enhanced efficiency in the ability to shift between mental sets. We compared the performance of monolingual and fluent bilingual college students in a task-switching paradigm. Bilinguals incurred reduced switching costs in the task-switching paradigm when compared with…

  18. Machine Tool Series. Duty Task List. (United States)

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This task list is intended for use in planning and/or evaluating a competency-based course to prepare machine tool, drill press, grinding machine, lathe, mill, and/or power saw operators. The listing is divided into six sections, with each one outlining the tasks required to perform the duties that have been identified for the given occupation.…

  19. Using Perceptrons to Explore the Reorientation Task (United States)

    Dawson, Michael R. W.; Kelly, Debbie M.; Spetch, Marcia L.; Dupuis, Brian


    The reorientation task is a paradigm that has been used extensively to study the types of information used by humans and animals to navigate in their environment. In this task, subjects are reinforced for going to a particular location in an arena that is typically rectangular in shape. The subject then has to find that location again after being…

  20. Metacognition in Monkeys during an Oculomotor Task (United States)

    Middlebrooks, Paul G.; Sommer, Marc A.


    This study investigated whether rhesus monkeys show evidence of metacognition in a reduced, visual oculomotor task that is particularly suitable for use in fMRI and electrophysiology. The 2-stage task involved punctate visual stimulation and saccadic eye movement responses. In each trial, monkeys made a decision and then made a bet. To earn…

  1. Designing Tasks for the Communicative Classroom. (United States)

    Nunan, David

    This book provides teachers with a practical introduction to the design and development of communicative language learning tasks. The ideas presented are relevant to teachers working in or preparing for a range of situations with a variety of learner types. First, some basic issues concerning communicative learning tasks are discussed, and the…

  2. Designing Tasks for the Communicative Classroom. (United States)

    Nunan, David

    This book provides teachers with a practical introduction to the design and development of communicative language learning tasks. The ideas presented are relevant to teachers working in or preparing for a range of situations with a variety of learner types. First, some basic issues concerning communicative learning tasks are discussed, and the…


    Directory of Open Access Journals (Sweden)

    Javed Ali


    Full Text Available Parallel computing systems compose task partitioning strategies in a true multiprocessing manner. Such systems share the algorithm and processing unit as computing resources which leads to highly inter process communications capabilities. The main part of the proposed algorithm is resource management unit which performs task partitioning and co-scheduling .In this paper, we present a technique for integrated task partitioning and co-scheduling on the privately owned network. We focus on real-time and non preemptive systems. A large variety of experiments have been conducted on the proposed algorithm using synthetic and real tasks. Goal of computation model is to provide a realistic representation of the costs of programming The results show the benefit of the task partitioning. The main characteristics of our method are optimal scheduling and strong link between partitioning, scheduling and communication. Some important models for task partitioning are also discussed in the paper. We target the algorithm for task partitioning which improve the inter process communication between the tasks and use the recourses of the system in the efficient manner. The proposed algorithm contributes the inter-process communication cost minimization amongst the executing processes.

  4. The Instructor as Manager: Time and Task. (United States)

    Collis, Betty; Nijhuis, Gerard Gervedink


    Discusses the use of information and communication technologies at the University of Twente (Netherlands) and considers the management tasks, defined as all tasks outside of content-specific aspects, related to online learning via the World Wide Web that instructors must address. Focuses on handling assignments and feedback. (LRW)

  5. Brief Family Therapy: A Metaphorical Task. (United States)

    de Shazer, Steve


    Presents a therapeutic procedure designed to prescribe the family's troublesome behavior pattern. A complement precedes delivering a task assignment. The metaphorical task redefines the serious complaint pattern into only one of the many options a family has for dealing with each other. A case study is presented. (Author/BEF)

  6. Task Analysis - Its Relation to Content Analysis. (United States)

    Gagne, Robert M.

    Task analysis is a procedure having the purpose of identifying different kinds of performances which are outcomes of learning, in order to make possible the specification of optimal instructional conditions for each kind of outcome. Task analysis may be related to content analysis in two different ways: (1) it may be used to identify the probably…

  7. Trading a Problem-solving Task (United States)

    Matsubara, Shigeo

    This paper focuses on a task allocation problem, especially cases where the task is to find a solution in a search problem or a constraint satisfaction problem. If the search problem is hard to solve, a contractor may fail to find a solution. Here, the more computational resources such as the CPU time the contractor invests in solving the search problem, the more a solution is likely to be found. This brings about a new problem that a contractee has to find an appropriate level of the quality in a task achievement as well as to find an efficient allocation of a task among contractors. For example, if the contractee asks the contractor to find a solution with certainty, the payment from the contractee to the contractor may exceed the contractee's benefit from obtaining a solution, which discourages the contractee from trading a task. However, solving this problem is difficult because the contractee cannot ascertain the contractor's problem-solving ability such as the amount of available resources and knowledge (e.g. algorithms, heuristics) or monitor what amount of resources are actually invested in solving the allocated task. To solve this problem, we propose a task allocation mechanism that is able to choose an appropriate level of the quality in a task achievement and prove that this mechanism guarantees that each contractor reveals its true information. Moreover, we show that our mechanism can increase the contractee's utility compared with a simple auction mechanism by using computer simulation.

  8. Paternal Effectiveness in a Selected Cognitive Task. (United States)

    Acuff, Nancy Hamblen

    The immediate effectiveness of paternal instruction in a selected cognitive task was investigated. The sub-problems were (1) to compare paternal and maternal instruction, and (2) to analyze paternal instructional effectiveness with the son or the daughter. The cognitive task selected was the Goodenough-Harris Draw-A-Man Test. Subjects were 42…

  9. Shaping Academic Task Engagement with Percentile Schedules (United States)

    Athens, Elizabeth S.; Vollmer, Timothy R.; St. Peter Pipkin, Claire C.


    The purpose of this study was to examine the use of percentile schedules as a method of quantifying the shaping procedure in an educational setting. We compared duration of task engagement during baseline measurements for 4 students to duration of task engagement during a percentile schedule. As a secondary purpose, we examined the influence on…

  10. Workplace for analysis of task performance

    NARCIS (Netherlands)

    Bos, J; Mulder, LJM; van Ouwerkerk, RJ; Maarse, FJ; Akkerman, AE; Brand, AN; Mulder, LJM


    In current research on mental workload and task performance a large gap exists between laboratory based studies and research projects in real life working practice. Tasks conducted within a laboratory environment often lack a strong resemblance with real life working situations. This paper presents

  11. Multiagent task allocation in social networks

    NARCIS (Netherlands)

    De Weerdt, M.M.; Zhang, Y.; Klos, T.


    This paper proposes a new variant of the task allocation problem, where the agents are connected in a social network and tasks arrive at the agents distributed over the network. We show that the complexity of this problem remains NP-complete. Moreover, it is not approximable within some factor. In c

  12. Distributed Task Allocation in Social Networks

    NARCIS (Netherlands)

    De Weerdt, M.M.; Zhang, Y.; Klos, T.


    This paper proposes a new variant of the task allocation problem, where the agents are connected in a social network and tasks arrive at the agents distributed over the network. We show that the complexity of this problem remains NPhard. Moreover, it is not approximable within some factor. We develo

  13. Multiagent task allocation in social networks

    NARCIS (Netherlands)

    M.M. de Weerdt (Mathijs); Y. Zhang (Yingqian); T.B. Klos (Tomas)


    textabstractThis paper proposes a new variant of the task allocation problem, where the agents are connected in a social network and tasks arrive at the agents distributed over the network. We show that the complexity of this problem remains NP-complete. Moreover, it is not approximable within some

  14. Transient terminal Cu-nitrene intermediates from discrete dicopper nitrenes. (United States)

    Badiei, Yosra M; Krishnaswamy, Ammani; Melzer, Marie M; Warren, Timothy H


    Reaction of the copper(I) beta-diketiminate {[Me3NN]Cu}2(mu-toluene) with the aryl azide N3Ar (Ar = 3,5-Me2C6H3) in toluene results in immediate effervescence and formation of the dicopper nitrene {[Me3NN]Cu}2(mu-NAr) (2) in 77% yield. The X-ray structure of 2 shows nearly symmetric bonding of the nitrene to two Cu centers separated by 2.911(1) A with Cu-N distances of 1.794(5) and 1.808(5) A along with a Cu-N-Cu angle of 107.8(2) degrees . This structure is conceptually related to the dicopper carbenes {[MexNN]Cu}2(mu-CPh2) (x = 2 or 3) (Dai, X.; Warren J. Am. Chem. Soc. 2004, 126, 10085. Badiei, Y. M.; Warren J. Organomet. Chem. 2005, 690, 5989.) which exhibit shorter Cu-Cu distances (2.4635(7) or 2.485(1) A) and acute Cu-C-Cu angles (79.51(14) or 80.1(2) degrees ). Addition of the Cu(I) anilidoimine {[Me2AI]Cu}2 (prepared from CuOtBu and the aniline-imine H[Me2AI] in 77% yield) to a benzene-d6 solution of 2 results in the formation of two new anilidoimine complexes {[Me2AI]Cu(mu- NAr)Cu[Me3NN] (5) and {[Me2AI]Cu}2(mu-NAr) (6) as well as [Me3NN]Cu(benzene) over 3 h. These observations are consistent with the slow dissociation of a [Me3NN]Cu fragment from 2 to generate the transient terminal nitrenes [Me3NN]Cu=NAr and [Me2AI]Cu=NAr quickly trapped by the [Me2AI]Cu fragment to form the new unsymmetrical and symmetrical dicopper nitrenes 5 and 6. Preliminary reactivity studies indicate electrophilic reactivity at the nitrene moiety. Dicopper nitrene 2 reacts with 10 equiv PMe3 and CNtBu to give ArN=PMe3 and ArN=C=NtBu in 94% and 92% yields, respectively, with concomitant formation of [Me3NN]Cu(L) (L = PMe3 and CNtBu). Reaction between 2 and 2 equiv PMe3 allows for observation of the structurally characterized Cu(I) phosphaimide [Me3NN]Cu(ArN=PMe3) (7).

  15. Properties of electrodeposited CoFe/Cu multilayers: The effect of Cu layer thickness

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, Turgut, E-mail: [Deparment of Physics, Science and Literature Faculty, Balikesir University, 10100 Balikesir (Turkey); Kockar, Hakan, E-mail: [Deparment of Physics, Science and Literature Faculty, Balikesir University, 10100 Balikesir (Turkey); Alper, Mursel, E-mail: [Deparment of Physics, Science and Literature Faculty, Uludag University, 16059 Gorukle, Bursa (Turkey)


    CoFe/Cu multilayers were potentiostatically electrodeposited on Ti substrates as a function of different non-magnetic (Cu) layer thicknesses, and their characterizations were investigated. The compositional analysis performed by energy dispersive X-ray spectroscopy disclosed that the Cu content in the multilayers increased and the Co content decreased as non-magnetic layer was increased. However, the Fe content was almost stable. The scanning electron microscopy studies showed that the surface morphology of the films is strongly affected by the non-magnetic layer thickness, and X-ray diffraction was used to analyse the structural properties of the multilayers and revealed that the multilayers have face-centred cubic (fcc) structure and their preferred orientations change depending on the Cu layer thickness. In the case of magnetoresistance measurements of the multilayers performed at room temperature, the highest giant magnetoresistance (GMR) values exhibited for the films with the Cu layer thickness (6.0 nm) whereas the lowest GMR magnitudes were observed for the films without Cu layer. Therefore, the variations of the Cu layer thicknesses were observed to have a significant effect on the GMR of multilayers. The differences observed in the magnetotransport properties were attributed to the microstructural changes caused by the Cu layer thickness. - Highlights: • CoFe/Cu multilayers were potentiostatically electrodeposited on Ti substrates. • Microstructural and magnetoresistance properties of CoFe/Cu multilayers were investigated. • All films had a face-centred cubic structure irrespective of the multilayer content. • All samples exhibited GMR and the maximum GMR value was 11%.

  16. The politics of attention contextualized: gaze but not arrow cuing of attention is moderated by political temperament. (United States)

    Carraro, Luciana; Dalmaso, Mario; Castelli, Luigi; Galfano, Giovanni


    It is known that an averted gaze can trigger shifts of attention in an observer, a phenomenon known as gaze-cuing effect. Recently, Dodd et al. (Atten Percept Psychophys 73:24-29, 2011) have reported a reliable gaze-cuing effect for liberals but not for conservatives. The present study tested whether this result is gaze-specific or extends over nonsocial spatial signals. Conservatives and liberals took part in a spatial-cuing task in which centrally placed gaze and arrow cues, pointing rightward or leftward, were followed by a peripheral onset target requiring a simple detection response. Whereas a reliable cuing effect was present for both gaze and arrow cues in the case of liberals, conservatives showed a reduced cuing response only for gaze cues. These results provide further support for the pattern reported by Dodd et al. (2011) and are consistent with the view that conservatives are less susceptible to the influence of spatial cues provided by other individuals.


    Directory of Open Access Journals (Sweden)

    Pavol Šebo


    Full Text Available Developing and microstructure of lead-free Sn-Cu solders containing 3, 5 and 10 wt. % of copper in bulk as well as in ribbon form is presented. Wetting of copper substrate by these solders at the temperatures 300, 350 and 400°C in air (partially in N2+10H2 during 1800 s was studied by sessile drop method. Joints Cu – solder – Cu were prepared at 300°C and 1800 s in air as well as in gas mix and their shear strength was measured. The microstructure was studied by light and scanning electron microscopy (SEM equipped with energy dispersive X-ray analyzer and standard X-ray diffraction machine. Wetting angle decreases with increasing wetting temperature. Wetting angle increased for higher (10 wt. % amount of copper in solder. Shear strength of the joints decreases with increasing the copper concentration in solder.

  18. Reconsideration of the simulated work task situation

    DEFF Research Database (Denmark)

    Borlund, Pia; Schneider, Jesper Wiborg


    The present paper reports on the initial study and the preliminary findings of how the concept of simulated work task situation is reported used in the research literature. The overall objective of the study is in a systematic manner to learn how and for what types of evaluations the concept...... is applied. In particular we are interested to learn whether the recommendations for how to apply simulated work task situations are followed. The preliminary findings indicate a need for clarifications of the recommendations of how to use simulated work task situations. Particularly with respect to ‘realism......’ of the simulated work task situations, which is emphasised through the need for tailoring of the simulated work task situations towards the group of study participant to ensure the depicted situations are realistic and interesting from the participants’ point of view. Likewise it seems that the recommendation...

  19. Deriving directions through procedural task analysis. (United States)

    Yuen, H K; D'Amico, M


    Task analysis is one of the essential components of activity analysis. Procedural task analysis involves breaking down an activity into a sequence of steps. Directions are the sequence of steps resulting from the task analysis (i.e., the product of the task analysis). Directions become a guide for caregivers or trainers use in teaching clients a specific skill. However, occupational therapy students often have difficulty in writing directions that are clear enough for caregivers or trainers to carry out. Books on activity analysis only provide examples of directions without giving guidelines on how to perform the writing process. The purposes of this paper are to describe the process of procedural task analysis and to provide a guideline for writing steps of directions.

  20. Task-specific dystonia: pathophysiology and management. (United States)

    Sadnicka, Anna; Kassavetis, Panagiotis; Pareés, Isabel; Meppelink, Anne Marthe; Butler, Katherine; Edwards, Mark


    Task-specific dystonia is a form of isolated focal dystonia with the peculiarity of being displayed only during performance of a specific skilled motor task. This distinctive feature makes task-specific dystonia a particularly mysterious and fascinating neurological condition. In this review, we cover phenomenology and its increasingly broad-spectrum risk factors for the disease, critically review pathophysiological theories and evaluate current therapeutic options. We conclude by highlighting the unique features of task-specific dystonia within the wider concept of dystonia. We emphasise the central contribution of environmental risk factors, and propose a model by which these triggers may impact on the motor control of skilled movement. By viewing task-specific dystonia through this new lens which considers the disorder a modifiable disorder of motor control, we are optimistic that research will yield novel therapeutic avenues for this highly motivated group of patients.

  1. Error Sonification of a Complex Motor Task

    Directory of Open Access Journals (Sweden)

    Riener Robert


    Full Text Available Visual information is mainly used to master complex motor tasks. Thus, additional information providing augmented feedback should be displayed in other modalities than vision, e.g. hearing. The present work evaluated the potential of error sonification to enhance learning of a rowing-type motor task. In contrast to a control group receiving self-controlled terminal feedback, the experimental group could not significantly reduce spatial errors. Thus, motor learning was not enhanced by error sonification, although during the training the participant could benefit from it. It seems that the motor task was too slow, resulting in immediate corrections of the movement rather than in an internal representation of the general characteristics of the motor task. Therefore, further studies should elaborate the impact of error sonification when general characteristics of the motor tasks are already known.

  2. Robot Task Commander with Extensible Programming Environment (United States)

    Hart, Stephen W (Inventor); Yamokoski, John D. (Inventor); Wightman, Brian J (Inventor); Dinh, Duy Paul (Inventor); Gooding, Dustin R (Inventor)


    A system for developing distributed robot application-level software includes a robot having an associated control module which controls motion of the robot in response to a commanded task, and a robot task commander (RTC) in networked communication with the control module over a network transport layer (NTL). The RTC includes a script engine(s) and a GUI, with a processor and a centralized library of library blocks constructed from an interpretive computer programming code and having input and output connections. The GUI provides access to a Visual Programming Language (VPL) environment and a text editor. In executing a method, the VPL is opened, a task for the robot is built from the code library blocks, and data is assigned to input and output connections identifying input and output data for each block. A task sequence(s) is sent to the control module(s) over the NTL to command execution of the task.

  3. Trait Mindfulness and Cognitive Task Performance

    Directory of Open Access Journals (Sweden)

    Emalee J. W. Quickel


    Full Text Available Mindfulness meditation (MM training has been shown to have positive effects on working memory and focused attention tasks. Clarifying the construct of mindfulness is important so that mindfulness can be studied effectively in individual differences and cognition research. The current study tested whether trait mindfulness alone explains any of the variability on task performance. Five commonly used mindfulness scales, as well as six standardized and experimental attention and working memory tasks were administered to 164 participants with no meditation experience. Confirmatory factor analysis found that the common variance denoted by measures of trait mindfulness is unrelated to the common variance among tasks requiring focused attention. These results indicate that mindfulness scales may not be capturing the attentional aspects of mindfulness. Individuals who score high on mindfulness scales do not perform better on focused attention tasks than those who score lower on mindfulness scales. These results have implications for defining and operationalizing mindfulness.

  4. Task mapping for non-contiguous allocations.

    Energy Technology Data Exchange (ETDEWEB)

    Leung, Vitus Joseph; Bunde, David P.; Ebbers, Johnathan; Price, Nicholas W.; Swank, Matthew.; Feer, Stefan P.; Rhodes, Zachary D.


    This paper examines task mapping algorithms for non-contiguously allocated parallel jobs. Several studies have shown that task placement affects job running time for both contiguously and non-contiguously allocated jobs. Traditionally, work on task mapping either uses a very general model where the job has an arbitrary communication pattern or assumes that jobs are allocated contiguously, making them completely isolated from each other. A middle ground between these two cases is the mapping problem for non-contiguous jobs having a specific communication pattern. We propose several task mapping algorithms for jobs with a stencil communication pattern and evaluate them using experiments and simulations. Our strategies improve the running time of a MiniApp by as much as 30% over a baseline strategy. Furthermore, this improvement increases markedly with the job size, demonstrating the importance of task mapping as systems grow toward exascale.

  5. Net-Based Task Management System

    Institute of Scientific and Technical Information of China (English)

    LIQiang; TIANLing; TONGBing-shu


    In net-based collaborative design environment, design resources become more and more varied and complex. Besides common information management systems, design resources can be organized in connection with design activities. A set of activities and resources linked by logic relations can form a task. A task has at least one objective and can be broken down into smaller ones. So a design project can be separated into many subtasks forming a hierarchical structure. Task Management System (TMS) is designed to break down these tasks and assign certain resources to its related task nodes. As a result of decomposition, all design resources and activities could be managed via this system. Based on this idea, we realized a TMS which manages collaborative resources in web environment.

  6. Learning to Model Task-Oriented Attention

    Directory of Open Access Journals (Sweden)

    Xiaochun Zou


    Full Text Available For many applications in graphics, design, and human computer interaction, it is essential to understand where humans look in a scene with a particular task. Models of saliency can be used to predict fixation locations, but a large body of previous saliency models focused on free-viewing task. They are based on bottom-up computation that does not consider task-oriented image semantics and often does not match actual eye movements. To address this problem, we collected eye tracking data of 11 subjects when they performed some particular search task in 1307 images and annotation data of 2,511 segmented objects with fine contours and 8 semantic attributes. Using this database as training and testing examples, we learn a model of saliency based on bottom-up image features and target position feature. Experimental results demonstrate the importance of the target information in the prediction of task-oriented visual attention.

  7. Binuclear Cu(A) Formation in Biosynthetic Models of Cu(A) in Azurin Proceeds via a Novel Cu(Cys)2His Mononuclear Copper Intermediate. (United States)

    Chakraborty, Saumen; Polen, Michael J; Chacón, Kelly N; Wilson, Tiffany D; Yu, Yang; Reed, Julian; Nilges, Mark J; Blackburn, Ninian J; Lu, Yi


    Cu(A) is a binuclear electron transfer (ET) center found in cytochrome c oxidases (CcOs), nitrous oxide reductases (N₂ORs), and nitric oxide reductase (NOR). In these proteins, the Cu(A) centers facilitate efficient ET (kET > 10⁴s⁻¹) under low thermodynamic driving forces (10-90 mV). While the structure and functional properties of Cu(A) are well understood, a detailed mechanism of the incorporation of copper into the protein and the identity of the intermediates formed during the Cu(A) maturation process are still lacking. Previous studies of the Cu(A) assembly mechanism in vitro using a biosynthetic model Cu(A) center in azurin (Cu(A)Az) identified a novel intermediate X (Ix) during reconstitution of the binuclear site. However, because of the instability of Ix and the coexistence of other Cu centers, such as Cu(A)' and type 1 copper centers, the identity of this intermediate could not be established. Here, we report the mechanism of Cu(A) assembly using variants of Glu114XCuAAz (X = Gly, Ala, Leu, or Gln), the backbone carbonyl of which acts as a ligand to the Cu(A) site, with a major focus on characterization of the novel intermediate Ix. We show that Cu(A) assembly in these variants proceeds through several types of Cu centers, such as mononuclear red type 2 Cu, the novel intermediate Ix, and blue type 1 Cu. Our results show that the backbone flexibility of the Glu114 residue is an important factor in determining the rates of T2Cu → Ix formation, suggesting that Cu(A) formation is facilitated by swinging of the ligand loop, which internalizes the T2Cu capture complex to the protein interior. The kinetic data further suggest that the nature of the Glu114 side chain influences the time scales on which these intermediates are formed, the wavelengths of the absorption peaks, and how cleanly one intermediate is converted to another. Through careful understanding of these mechanisms and optimization of the conditions, we have obtained Ix in ∼80

  8. Explosive compaction of CuCr alloys

    Institute of Scientific and Technical Information of China (English)

    李金平; 罗守靖; 龚朝晖; 牛玮; 纪松


    The production of CuCr alloys utilizing explosive compaction was studied. Mixture powders of CuCr alloys placed in tubes with a dimension of d14.0mm×21.4mm can be compacted using explosive pads of 16.5mm or 22.5mm. Thicker pads of explosive make the compacts more porous. The effects of the ratio of me/mp, ratio of me/(mp+mt) and impact energy on the density of compacts were similar, they were chosen to control explosive compaction, respectively. When adequate value of the parameters me/mp, me/(mt+mp) and impact energy of unit area of tube was chosen, high density(7.858g/cm3), high hardness(HB189) and low conductance (13.6MS/m) of CuCr alloys could be made by explosive compaction. The general properties of CuCr alloys by explosive compaction are similar to those of CuCr alloys by traditional process.

  9. Mechanism for Cu2+ Sorption on Palygorskite

    Institute of Scientific and Technical Information of China (English)

    CHEN Tian-Hu; PENG Shu-Chuan; XU Hui-Fang; SHI Xiao-Li; HUANG Chuan-Hui


    A single-factor experiment of copper ion adsorption on pure palygorskite was carried out to understand the Cu2+ sorption of palygorskite-an important clay mineral in soil and sedimentary rock. In addition, pH of the solution and the surface microstructure of palygorskite were investigated before and after adsorption. The experimental results indicated that efficiency of Cu2+ removal was related to the oscillation rate of the specimen shaker, sorption time, initial pH value and the amount of adsorbent added. Palygorskite induced Cu2+ hydrolysis and interaction between copper hydroxide colloids and palygorskite surfaces, as observed with transmission electron microscopy (TEM), were the main contributions to palygorskite removal of Cu2+. This mechanism was different from adsorption at the mineral-water interface. It was proposed that surface hydrolysis of palygorskite raised the alkalinity of the palygorskite-water interface and suspension system. Thus, the induced pH of the solution was then high enough for Cu2+ hydrolysis on the mineral surface and in solution.

  10. Task Repetition Effects on L1 Use in EFL Child Task-Based Interaction (United States)

    Azkarai, Agurtzane; García Mayo, María del Pilar


    Research has shown that tasks provide second language (L2) learners with many opportunities to learn the L2. Task repetition has been claimed to benefit L2 learning since familiarity with procedure and/or content gives learners the chance to focus on more specific aspects of language. Most research on task repetition has focused on adult…

  11. Cognitive Complexity of Mathematics Instructional Tasks in a Taiwanese Classroom: An Examination of Task Sources (United States)

    Hsu, Hui-Yu; Silver, Edward A.


    We examined geometric calculation with number tasks used within a unit of geometry instruction in a Taiwanese classroom, identifying the source of each task used in classroom instruction and analyzing the cognitive complexity of each task with respect to 2 distinct features: diagram complexity and problem-solving complexity. We found that…

  12. The Effect of Focus on Form and Task Complexity on L2 Learners' Oral Task Performance (United States)

    Salimi, Asghar


    Second Language learners' oral task performance has been one of interesting and research generating areas of investigations in the field of second language acquisition specially, task-based language teaching and learning. The main purpose of the present study is to investigate the effect of focus on form and task complexity on L2 learners' oral…

  13. Promoting Task-Based Pragmatics Instruction in EFL Classroom Contexts: The Role of Task Complexity (United States)

    Kim, Youjin; Taguchi, Naoko


    Robinson's (2001) Cognition Hypothesis claims that more complex tasks promote interaction and language development. This study examined the effect of task complexity in the learning of request-making expressions. Task complexity was operationalized as [+/- reasoning] following Robinson's framework. The study employed a pretest-posttest research…

  14. Environmentally cued hatching in reptiles. (United States)

    Doody, J S


    Evidence is accumulating for the widespread occurrence of environmentally cued hatching (ECH) in animals, but its diversity and distribution across taxa are unknown. Herein I review three types of ECH in reptiles: early hatching, delayed hatching, and synchronous hatching. ECH is currently known from 43 species, including turtles, crocodilians, lizards, snakes, tuatara, and possibly worm lizards. Early hatching caused by physical disturbance (e.g., vibrations) is the most commonly reported ECH across all groups; although it apparently serves an antipredator function in some species, its adaptive value is unknown in most. Delayed hatching, characterized by metabolic depression or embryonic aestivation, and sometimes followed by a hypoxic cue (flooding), occurs in some turtles and possibly in monitor lizards and crocodilians; in some of these species delayed hatching serves to defer hatching from the dry season until the more favorable conditions of the wet season. Synchronous hatching, whereby sibling eggs hatch synchronously despite vertical thermal gradients in the nest, occurs in some turtles and crocodilians. Although vibrations and vocalizations in hatching-competent embryos can stimulate synchronous hatching, cues promoting developmentally less advanced embryos to catch up with more advanced embryos have not been confirmed. Synchronous hatching may serve to dilute predation risk by promoting synchronous emergence or reduce the period in which smells associated with hatching can attract predators to unhatched eggs. Within species, advancing our understanding of ECH requires three types of studies: (1) experiments identifying hatching cues and the plastic hatching period, (2) experiments disentangling hypotheses about multiple hatching cues, and (3) investigations into the environmental context in which ECH might evolve in different species (major predators or abiotic influences on the egg, embryo, and hatchling). Among species and groups, surveys for ECH are

  15. Cu patterning on Si substrate using solution-processed Ti-Cu oxide films and electroless plating (United States)

    Miyazeki, Yusuke; Horiuchi, Yoshio; Noh, Joo-Hyong; Cordonier, Christopher E. J.; Honma, Hideo; Arakawa, Taro


    We demonstrated for the first time the Cu patterning on Si using Ti and Cu oxide (TiCu-ox) films patterned by photolithography and electroless plating without etching or surface modification. The TiCu-ox films had a porous structure and acted as adhesion layers. The TiCu-ox films were patterned by photolithography on Si and glass for comparison, followed by Cu deposition by electroless plating. Fine Cu patterns on the patterned TiCu-ox films were formed. The smallest line/space widths on glass and Si were 3.2/0.8 and 3.6/4.4 µm, respectively. The deposited Cu layers had high adhesion strength and low sheet resistance.

  16. Effect of Cu content and temperature on the properties of Cu2ZnSnSe4 solar cells (United States)

    Sahayaraj, Sylvester; Brammertz, Guy; Buffière, Marie; Meuris, Marc; Vleugels, Jef; Poortmans, Jef


    The complexity involved in obtaining pure Kesterite Cu2ZnSnSe4 (CZTSe) thin film primarily arises due to its narrow region of stability, leading to the presence of unavoidable binary selenides of the constituent metals. This study offers an insight on the formation of Cu selenides when the amount of Cu is varied in the precursor from Cu poor to Cu rich. The amount of Cu selenides was found to decrease when the composition of CZTSe absorber approached Cu rich conditions but functional devices were not obtained. Detailed characterizations also showed that the Cu and Sn binary phases were present at the backside interface of CZTSe solar cells. However with an increase in the selenization temperature it was found that the amount of Cu selenides and other secondary phases could be drastically minimized or even eliminated leading to high efficiency devices.

  17. Effect of Cu content and temperature on the properties of Cu2ZnSnSe4 solar cells

    Directory of Open Access Journals (Sweden)

    Sahayaraj Sylvester


    Full Text Available The complexity involved in obtaining pure Kesterite Cu2ZnSnSe4 (CZTSe thin film primarily arises due to its narrow region of stability, leading to the presence of unavoidable binary selenides of the constituent metals. This study offers an insight on the formation of Cu selenides when the amount of Cu is varied in the precursor from Cu poor to Cu rich. The amount of Cu selenides was found to decrease when the composition of CZTSe absorber approached Cu rich conditions but functional devices were not obtained. Detailed characterizations also showed that the Cu and Sn binary phases were present at the backside interface of CZTSe solar cells. However with an increase in the selenization temperature it was found that the amount of Cu selenides and other secondary phases could be drastically minimized or even eliminated leading to high efficiency devices.

  18. Corrosion Resistance of Zn and Cu Coated Steel Pipes as a Substitute for Cu Pipe in an Air Conditioner System

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jae Gyeong; Park, Chan Jin; Hong, Sung Kil [Chonnam National University, Gwangju (Korea, Republic of)


    We investigated the corrosion resistance of Zn and Cu coated steel pipes as a substitute for Cu pipe in an air-conditioner system. In addition, the galvanic corrosion tendency between two dissimilar metal parts was studied. The corrosion resistance of the Cu electroplated steel was similar to that of Cu, while the corrosion rate of the Zn electro-galvanized and the galvalume (Zn-55 % Al) coated steels was much higher and not suitable for Cu substitute in artificial sea water and acidic rain environments. Furthermore, the galvanic difference between Cu electroplated steel and Cu was so small that the Cu coated steel pipe can be used as a substitute for Cu pipe in an air-conditioner system.

  19. Developing Bayesian adaptive methods for estimating sensitivity thresholds (d') in Yes-No and forced-choice tasks. (United States)

    Lesmes, Luis A; Lu, Zhong-Lin; Baek, Jongsoo; Tran, Nina; Dosher, Barbara A; Albright, Thomas D


    Motivated by Signal Detection Theory (SDT), we developed a family of novel adaptive methods that estimate the sensitivity threshold-the signal intensity corresponding to a pre-defined sensitivity level (d' = 1)-in Yes-No (YN) and Forced-Choice (FC) detection tasks. Rather than focus stimulus sampling to estimate a single level of %Yes or %Correct, the current methods sample psychometric functions more broadly, to concurrently estimate sensitivity and decision factors, and thereby estimate thresholds that are independent of decision confounds. Developed for four tasks-(1) simple YN detection, (2) cued YN detection, which cues the observer's response state before each trial, (3) rated YN detection, which incorporates a Not Sure response, and (4) FC detection-the qYN and qFC methods yield sensitivity thresholds that are independent of the task's decision structure (YN or FC) and/or the observer's subjective response state. Results from simulation and psychophysics suggest that 25 trials (and sometimes less) are sufficient to estimate YN thresholds with reasonable precision (s.d. = 0.10-0.15 decimal log units), but more trials are needed for FC thresholds. When the same subjects were tested across tasks of simple, cued, rated, and FC detection, adaptive threshold estimates exhibited excellent agreement with the method of constant stimuli (MCS), and with each other. These YN adaptive methods deliver criterion-free thresholds that have previously been exclusive to FC methods.

  20. Electrical Breakdown Characteristic of Nanostructured W-Cu Contacts Materials

    Institute of Scientific and Technical Information of China (English)

    WANG Junbo; CHEN Wen'ge; DING Bingjun


    Nanostructured (NS) W- Cu composite powder was prepared by mechanical alloying ( MA ), and nanostructured bulk of W- Cu contact material was fabricated by hot press sintering in an electrical vacuum furnace. The microstructure, electric conductivity, hardness and break down voltage of NS W-Cu alloys were measured and compared to those of conventional W- Cu alloys prepared by powder metallurgy. The experimental results show that microstructural refinement and uniformity can improve the breakdown behavior and the electric arc stability of nanostructured W- Cu contacts materials. Also, the nanostructured W- Cu contact material shows the characteristic of spreading electric arcs, which is of benefit to electric arc erosion.

  1. Atom probe study of Cu-poor to Cu-rich transition during Cu(In,Ga)Se{sub 2} growth

    Energy Technology Data Exchange (ETDEWEB)

    Couzinie-Devy, F.; Cadel, E.; Pareige, P. [Groupe de Physique des Materiaux (GPM), UMR 6634 CNRS, Universite et INSA de Rouen, Avenue de l' Universite BP 12, 76801 Saint Etienne du Rouvray (France); Barreau, N.; Arzel, L. [Institut des Materiaux Jean Rouxel (IMN), UMR 6502 CNRS, 2 rue de la Houssiniere BP 32229, 44322 Nantes cedex 3 (France)


    Atomic scale chemistry of polycrystalline Cu(In,Ga)Se{sub 2} (CIGSe) thin film has been characterized at key points of the 3-stage process using atom probe tomography. 3D atom distributions have been reconstructed when the layer is Cu-poor ([Cu]/([Ga] + [In]) < 1), Cu-rich ([Cu]/([Ga] + [In]) > 1), and at the end of the process. Particular attention has been devoted to grain boundary composition and Na atomic distribution within the CIGSe layer. Significant variation of composition is highlighted during the growing process, providing fundamental information helping the understanding of high efficiency CIGSe formation.

  2. Simulations of Metal Cu in Heating Process

    Institute of Scientific and Technical Information of China (English)

    ZHANG, Tao(张弢); WU, Ai-Ling(吴爱玲); GUAN, Li(管立); QI, Yuan-Hua(齐元华)


    Based on the Finnis-Sinsclair (FS) many-body potential model, the melting process of a system, which consists of 500 Cu atoms, controlled by period boundary condition has been simulated. The means of pair correlation function, mean square displacement and Honeycutt-Anderson bonded pair have been used to characterize the melting behavior of Cu at different heating rates. The simulation indicates that melting point of metal Cu is 1444 K during a continuous heating process, and the calculated diffusion constant at the melting point is 4.31×10-9 m2/s. These results are better than those from the EAM method, showing that the FS potential model works well in some disordered systems.

  3. Oxide Nanotube Analogues: CuO Nanobarrels

    Energy Technology Data Exchange (ETDEWEB)

    H. H. Farrell; R. D. Parra


    The principle 'form follows function' which dominated much of twentieth century architechture and industrial design has its parallel on the nanolevel in the concept of 'function follows form'. This has been realized in many technologically valuable ways on this level via nanoparticles such as nanotubes and quantum dots, for example. Now, a new material, copper oxide (CuO) nanobarrels, offers still another opportunity to exploit unusual form to obtain new functionality. Recently, CuO 'rings' on the order of 100 nm diameter have been observed experimentally by El-Azab and Liang (2003). In a separate effort, we have used first principles density functional calculations to investigate smaller, single walled CuO structures that appear to be nanotubes or nanobarrels with a square unit mesh rather than the hexagonal mesh of carbon nanotubes. These structures are unique and novel, and almost certainly will yield fascinating results when studied experimentally.

  4. Cuing consumerism: situational materialism undermines personal and social well-being. (United States)

    Bauer, Monika A; Wilkie, James E B; Kim, Jung K; Bodenhausen, Galen V


    Correlational evidence indicates that materialistic individuals experience relatively low levels of well-being. Across four experiments, we found that situational cuing can also trigger materialistic mind-sets, with similarly negative personal and social consequences. Merely viewing desirable consumer goods resulted in increases in materialistic concerns and led to heightened negative affect and reduced social involvement (Experiment 1). Framing a computer task as a "Consumer Reaction Study" led to a stronger automatic bias toward values reflecting self-enhancement, compared with framing the same task as a "Citizen Reaction Study" (Experiment 2). Consumer cues also increased competitiveness (Experiment 3) and selfishness in a water-conservation dilemma (Experiment 4). Thus, the costs of materialism are not localized only in particularly materialistic people, but can also be found in individuals who happen to be exposed to environmental cues that activate consumerism-cues that are commonplace in contemporary society.

  5. Involuntary conscious memory facilitates cued recall performance: further evidence that chaining occurs during voluntary recall. (United States)

    Mace, John H


    Recent studies have shown that conscious recollection of the past occurs spontaneously when subjects voluntarily recall their own past experiences or a list of previously studied words. Naturalistic diary studies and laboratory studies of this phenomenon, often called involuntary conscious memory (ICM), show that it occurs in 2 ways. One is direct ICM retrieval, which occurs when a cue spontaneously triggers a conscious memory; the other is chained ICM retrieval, which occurs when a retrieved conscious memory spontaneously triggers another. Laboratory studies investigating ICM show that chained ICM retrieval occurs on voluntary autobiographical memory tasks. The present results show that chained ICM retrieval also occurs on a voluntary word list memory task (cued recall). These results are among a handful suggesting that ICM retrieval routinely occurs during voluntary recall.

  6. Overview of the ID, EPI and REL tasks of BioNLP Shared Task 2011

    Directory of Open Access Journals (Sweden)

    Pyysalo Sampo


    Full Text Available Abstract We present the preparation, resources, results and analysis of three tasks of the BioNLP Shared Task 2011: the main tasks on Infectious Diseases (ID and Epigenetics and Post-translational Modifications (EPI, and the supporting task on Entity Relations (REL. The two main tasks represent extensions of the event extraction model introduced in the BioNLP Shared Task 2009 (ST'09 to two new areas of biomedical scientific literature, each motivated by the needs of specific biocuration tasks. The ID task concerns the molecular mechanisms of infection, virulence and resistance, focusing in particular on the functions of a class of signaling systems that are ubiquitous in bacteria. The EPI task is dedicated to the extraction of statements regarding chemical modifications of DNA and proteins, with particular emphasis on changes relating to the epigenetic control of gene expression. By contrast to these two application-oriented main tasks, the REL task seeks to support extraction in general by separating challenges relating to part-of relations into a subproblem that can be addressed by independent systems. Seven groups participated in each of the two main tasks and four groups in the supporting task. The participating systems indicated advances in the capability of event extraction methods and demonstrated generalization in many aspects: from abstracts to full texts, from previously considered subdomains to new ones, and from the ST'09 extraction targets to other entities and events. The highest performance achieved in the supporting task REL, 58% F-score, is broadly comparable with levels reported for other relation extraction tasks. For the ID task, the highest-performing system achieved 56% F-score, comparable to the state-of-the-art performance at the established ST'09 task. In the EPI task, the best result was 53% F-score for the full set of extraction targets and 69% F-score for a reduced set of core extraction targets, approaching a level

  7. Access to a CuII–O–CuII Motif: Spectroscopic Properties, Solution Structure, and Reactivity (United States)

    Haack, Peter; Kärgel, Anne; Greco, Claudio; Dokic, Jadranka; Braun, Beatrice; Pfaff, Florian F.; Mebs, Stefan; Ray, Kallol; Limberg, Christian


    We report a complex with a rare CuII–O–CuII structural motif that is stable at room temperature, which allows its in-depth characterization by a variety of spectroscopic methods. Interest in such compounds is fueled by the recent discovery that a CuII–O–CuII species on the surface of Cu-ZSM-5 is capable of oxidizing methane to methanol and this in turn ties into mechanistic discussions on the methane oxidation at the dicopper site within the particulate methane monooxygenase. For the synthesis of our Cu2O complex we have developed a novel, neutral ligand system, FurNeu, exhibiting two N-(N',N'-dimethylaminoethyl)(2-pyridylmethyl)amino binding pockets connected by a dibenzofuran spacer. The reaction of FurNeu with CuCl yielded [FurNeu](Cu2(μ-Cl))(CuCl2), 1, demonstrating the geometric potential of the ligand to stabilize Cu–X–Cu moieties. A CuI precursor with weakly coordinating anions was chosen in the next step, namely [Cu(NCCH3)4]OTf, which led to the formation of [FurNeu](Cu(NCCH3))2(OTf)2, 3. Treatment of 3 with O2 or PhIO led to identical green solutions, whose UV/Vis spectra were markedly different from the one displayed by [FurNeu](Cu)2(OTf)4, 4, prepared independently from FurNeu and Cu(OTf)2. Further investigations including PhIO consumption experiments, NMR and UV/Vis spectroscopy, HR-ESI mass spectrometry and protonation studies led to the identification of the green product as [FurNeu](Cu2(μ-O))(OTf)2, 5. DOSY NMR spectroscopy confirmed its monomeric character. Over longer periods of time 5 decomposes to give [Cu(picoloyl)2], formed through an oxidative N-dealkylation reaction followed by further oxidation of the ligand. Due to its slow decomposition reaction all attempts to crystallize 5 failed. However, its structure in solution could be determined by EXAFS analysis in combination with DFT calculations, which revealed a Cu–O–Cu angle that amounts to 105.17°. Moreover, TDDFT calculations helped to rationalize the UV/Vis absorptions

  8. Survival Processing and the Stroop Task

    Directory of Open Access Journals (Sweden)

    Stephanie A. Kazanas


    Full Text Available This study was designed to investigate the impact of survival processing with a novel task for this paradigm: the Stroop color-naming task. As the literature is mixed with regard to task generalizability, with survival processing promoting better memory for words, but not better memory for faces or paired associates, these types of task investigations are important to a growing field of research. Using the Stroop task provides a unique contribution, as identifying items by color is an important evolutionary adaptation and not specific to humans as is the case with word recall. Our results indicate that survival processing, with its accompanying survival-relevance rating task, remains the best mnemonic strategy for word memory. However, our results also indicate that presenting the survival passage does not motivate better color-naming performance than color-naming alone. In addition, survival processing led to a larger amount of Stroop interference, though not significantly larger than the other conditions. Together, these findings suggest that considering one’s survival when performing memory and attention-based tasks does not enhance cognitive performance generally, although greater allocation of attentional resources to color-incongruent concrete objects could be considered adaptive. These findings support the notion that engaging in deeper processing via survival-relevance ratings may preserve these words across a variety of experimental manipulations.

  9. Mechanochemical synthesis of Cu-Al and methyl orange intercalated Cu-Al layered double hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jun, E-mail: [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); He, Xiaoman; Chen, Min; Hu, Huimin [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); Zhang, Qiwu, E-mail: [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); Liu, Xinzhong [College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350118 China (China)


    In this study, a mechanochemical route to synthesize a Cu-Al layered double hydroxide (LDH) and a methyl orange (MO) intercalated one (MO-LDH) was introduced, in which basic cupric carbonate (Cu{sub 2}(OH){sub 2}CO{sub 3}) and aluminum hydroxide (Al(OH){sub 3}) with Cu/Al molar ratio at 2/1 was first dry ground for 2 h and then agitated in water or methyl orange solution for another 4 h to obtain the LDH and MO-LDH products without any heating operation. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG), Differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). The products showed high crystallinity phase of Cu-Al and MO intercalated Cu-Al LDH with no evident impurities, proving that the craft introduced here was facile and effective. The new idea can be applied in other fields to produce organic-inorganic composites. - Highlights: • A facile mechanochemical route to synthesize Cu-Al and MO intercalated Cu-Al LDH. • The products possesses high crystalline of LDH phase with no impure phases. • The dry milling process induces the element substitution between the raw materials. • The agitation operation helps the grain growth of LDH.

  10. Characterization of Cu-exchanged SSZ-13: a comparative FTIR, UV-Vis, and EPR study with Cu-ZSM-5 and Cu-β with similar Si/Al and Cu/Al ratios

    DEFF Research Database (Denmark)

    Giordanino, Filippo; Vennestrøm, Peter N. R.; Lundegaard, Lars Fahl


    revealed the presence of different Cu2+ species. New data and discussion are devoted to (i) [Cu–OH]+ species likely balanced by one framework Al atom; (ii) mono(μ-oxo)dicopper [Cu2(μ-O)]2+ dimers observed in Cu-ZSM-5 and Cu-β, but not in Cu-SSZ-13. UV-Vis-NIR spectra of O2 activated samples reveal......Cu-SSZ-13 has been characterized by different spectroscopic techniques and compared with Cu-ZSM-5 and Cu-β with similar Si/Al and Cu/Al ratios and prepared by the same ion exchange procedure. On vacuum activated samples, low temperature FTIR spectroscopy allowed us to appreciate a high...... concentration of reduced copper centres, i.e. isolated Cu+ ions located in different environments, able to form Cu+(N2), Cu+(CO)n (n = 1, 2, 3), and Cu+(NO)n (n = 1, 2) upon interaction with N2, CO and NO probe molecules, respectively. Low temperature FTIR, DRUV-Vis and EPR analysis on O2 activated samples...

  11. Antibacterial activity and cytocompatibility of Cu-Ti-O nanotubes. (United States)

    Hang, Ruiqiang; Gao, Ang; Huang, Xiaobo; Wang, Xiaoguang; Zhang, Xiangyu; Qin, Lin; Tang, Bin


    TiO2 nanotubes (NTs) have favorable biological properties, but the poor antibacterial activity limits their application especially in orthopedics fields. In this article, Cu-Ti-O nanotubes with different Cu contents are fabricated on sputtered TiCu films. Scanning electron microscopy reveals the NTs can be formed on sputtered TiCu films when the Cu content is less than 14.6 at %. X-ray photoelectron spectroscopy results indicate the NTs are consist of CuO mixed with TiO2 and the Cu content in NTs decreases dramatically compared with that in TiCu films. Biological experiments show that although these NTs have poor release antibacterial activity, their contact antibacterial activity has proven to be excellent, indicating the NT surface can effectively inhibit biomaterial-associated infections. The cytocompatibility of the NTs is closely related to the Cu content and when its content is relatively low (1.01 at %), there is no appreciable cytotoxicity. So Cu-Ti-O NTs with 1 at % Cu may be suitable to achieve proper antibacterial activity and desired cytocompatibility. The Cu-Ti-O NTs integrate the favorable antibacterial activity of Cu and excellent biological properties of TiO2 NTs therefore have potential applications in orthopedics, dentistry, and other biomedical fields.

  12. Synthesis of Cu/Cu2O nanoparticles by laser ablation in deionized water and their annealing transformation into CuO nanoparticles

    KAUST Repository

    Gondal, M. A.


    Nano-structured Cupric Oxide (CuO) has been synthesized using pulsed laser ablation of pure copper in water using Q-switched pulsed laser beam of 532 nm wavelength and, 5 nanosecond pulse duration and laser pulse energy of 100 mJ/pulse. In the initial unannealed colloidal suspension, the nanoparticles of Copper (Cu) and Cuprious oxide (Cu2O) were identified. Further the suspension was dried and annealed at different temperatures and we noticed the product (Cu/Cu2O) was converted predominantly into CuO at annealing temperature of 300 \\'C for 3 hours. As the annealing temperature was raised from 300 to 900 \\'C, the grain sizes of CuO reduced to the range of 9 to 26 nm. The structure and the morphology of the prepared samples were investigated using X-ray diffraction and Transmission Electron Microscope. Photoluminescence and UV absorption spectrometrystudies revealed that the band gap and other optical properties of nano-structured CuO were changed due to post annealing. Fourier transform spectrometry also confirmed the transformation of Cu/Cu2O into CuO. Copyright © 2013 American Scientific Publishers All rights reserved.

  13. Characterization of p-CuI prepared by the SILAR technique on Cu-tape/n-CuInS{sub 2} for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sankapal, B.R. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany)]. E-mail:; Ennaoui, A. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany); Guminskaya, T. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany); Dittrich, Th. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany); Bohne, W. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany); Roehrich, J. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany); Strub, E. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany); Lux-Steiner, M.Ch. [Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109, Berlin (Germany)


    CuI has been synthesized at room temperature on Cu-tape/n-CuInS{sub 2} by using the SILAR technique (successive ionic layer adsorption and reaction). The influence of wet chemical iodine treatment on the CuI has been investigated in more detail. The films were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), elastic recoil detection analysis (ERDA) and surface photovoltage (SPV) techniques. The CuI films contain the no. gammano. -phase of the Zinkblende structure. The crystallites are preferentially oriented in the (111) direction. After wet chemical iodine treatment, the fibrous surface morphology changed to a more dense CuI film with larger crystallites. Oxides could not be detected on the CuI surface. The density of surface states of CIS decreased after the CuI deposition. The importance of the wet chemical iodine treatment for the performance of Cu-tape/n-CuInS{sub 2}/p-CuI solar cells has been demonstrated.

  14. Crystallization features of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} in the Y{sub 2}BaCuO{sub 5}-BaCuO{sub 2}-CuO and Y{sub 2}Cu{sub 2}O{sub 5}-BaCuO{sub 2} systems

    Energy Technology Data Exchange (ETDEWEB)

    Gurskii, L.I. [Belarusian State University of Informatics Science and Radioelectronics, Minsk (Belarus); Saad, A.M. [Al-Balqua Applied University, Salt (Jordan); Truhan, V.M.; Haliakevich, T.V. [Joint Institute of Solid State and Semiconductor Physics, NAS Belarus, Minsk (Belarus); Kalanda, N.A.


    Based on the data of X-ray phase and microstructure analysis, the sample composition was optimized in order to provide maximum size of the textured macrograins of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} and of the crystallites in the Y{sub 2}BaCuO{sub 5}-BaCuO{sub 2}-CuO, Y{sub 2}Cu{sub 2}O{sub 5}-BaCuO{sub 2} systems. The growth rate has been studied and the YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} growth activation energy has been calculated for the samples of Y{sub 2}BaCuO{sub 5}+3BaCuO{sub 2}+2.3CuO, Y{sub 2}BaCuO{sub 5}+3BaCuO{sub 2}+0.6CuO, and Y{sub 2}Cu{sub 2}O{sub 5}+3.5BaCuO{sub 2} compounds in the temperature range of 1240-1270 K for the case of use of the Y{sub 2}Cu{sub 2}O{sub 5} and Y{sub 2}BaCuO{sub 5} precursors with an average grain diameter of 10 {mu}m and 1 mm. A crystallization mechanism of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} in the Y{sub 2}BaCuO{sub 5}-BaCuO{sub 2}-CuO and Y{sub 2}Cu{sub 2}O{sub 5}-BaCuO{sub 2} systems in the case of different sizes of Y{sub 2}BaCuO{sub 5} and Y{sub 2}Cu{sub 2}O{sub 5} precursor grains was proposed and validated. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Corrosion and runoff rates of Cu and three Cu-alloys in marine environments with increasing chloride deposition rate. (United States)

    Odnevall Wallinder, Inger; Zhang, Xian; Goidanich, Sara; Le Bozec, Nathalie; Herting, Gunilla; Leygraf, Christofer


    Bare copper sheet and three commercial Cu-based alloys, Cu15Zn, Cu4Sn and Cu5Al5Zn, have been exposed to four test sites in Brest, France, with strongly varying chloride deposition rates. The corrosion rates of all four materials decrease continuously with distance from the coast, i.e. with decreasing chloride load, and in the following order: Cu4Sn>Cu sheet>Cu15Zn>Cu5Al5Zn. The patina on all materials was composed of two main layers, Cu2O as the inner layer and Cu2(OH)3Cl as the outer layer, and with a discontinuous presence of CuCl in between. Additional minor patina constituents are SnO2 (Cu4Sn), Zn5(OH)6(CO3)2 (Cu15Zn and Cu5Al5Zn) and Zn6Al2(OH)16CO3·4H2O/Zn2Al(OH)6Cl·2H2O/Zn5Cl2(OH)8·H2O and Al2O3 (Cu5Al5Zn). The observed Zn- and Zn/Al-containing corrosion products might be important factors for the lower sensitivity of Cu15Zn and Cu5Al5Zn against chloride-induced atmospheric corrosion compared with Cu sheet and Cu4Sn. Decreasing corrosion rates with exposure time were observed for all materials and chloride loads and attributed to an improved adherence with time of the outer patina to the underlying inner oxide. Flaking of the outer patina layer was mainly observed on Cu4Sn and Cu sheet and associated with the gradual transformation of CuCl to Cu2(OH)3Cl of larger volume. After three years only Cu5Al5Zn remains lustrous because of a patina compared with the other materials that appeared brownish-reddish. Significantly lower release rates of metals compared with corresponding corrosion rates were observed for all materials. Very similar release rates of copper from all four materials were observed during the fifth year of marine exposure due to an outer surface patina that with time revealed similar constituents and solubility properties. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  16. Enhanced sympathetic arousal in response to FMRI scanning correlates with task induced activations and deactivations.

    Directory of Open Access Journals (Sweden)

    Markus Muehlhan

    Full Text Available It has been repeatedly shown that functional magnetic resonance imaging (fMRI triggers distress and neuroendocrine response systems. Prior studies have revealed that sympathetic arousal increases, particularly at the beginning of the examination. Against this background it appears likely that those stress reactions during the scanning procedure may influence task performance and neural correlates. However, the question how sympathetic arousal elicited by the scanning procedure itself may act as a potential confounder of fMRI data remains unresolved today. Thirty-seven scanner naive healthy subjects performed a simple cued target detection task. Levels of salivary alpha amylase (sAA, as a biomarker for sympathetic activity, were assessed in samples obtained at several time points during the lab visit. SAA increased two times, immediately prior to scanning and at the end of the scanning procedure. Neural activation related to motor preparation and timing as well as task performance was positively correlated with the first increase. Furthermore, the first sAA increase was associated with task induced deactivation (TID in frontal and parietal regions. However, these effects were restricted to the first part of the experiment. Consequently, this bias of scanner related sympathetic activation should be considered in future fMRI investigations. It is of particular importance for pharmacological investigations studying adrenergic agents and the comparison of groups with different stress vulnerabilities like patients and controls or adolescents and adults.

  17. Differential preparation intervals modulate repetition processes in task switching: an ERP study

    Directory of Open Access Journals (Sweden)

    Min eWang


    Full Text Available In task-switching paradigms, reaction times (RTs switch cost (SC and the neural correlates underlying the SC are affected by different preparation intervals. However, little is known about the effect of the preparation interval on the repetition processes in task-switching. To examine this effect we utilized a cued task-switching paradigm with long sequences of repeated trials. Response-stimulus intervals (RSI and cue-stimulus intervals (CSI were manipulated in short and long conditions. Electroencephalography (EEG and behavioral data were recorded. We found that with increasing repetitions, RTs were faster in the short CSI conditions, while P3 amplitudes decreased in the LS (long RSI and short CSI conditions. Positive correlations between RT benefit and P3 activation decrease (repeat 1 minus repeat 5, and between the slope of the RT and P3 regression lines were observed only in the LS condition. Our findings suggest that differential preparation intervals modulate repetition processes in task switching.

  18. Extending the Failure-to-Engage theory of task switch costs. (United States)

    Poboka, Dane; Karayanidis, Frini; Heathcote, Andrew


    Failure-to-Engage (FTE, De Jong, 2000) theory explains slowed response time after switching tasks as in part due to participants sometimes failing to prepare. Brown et al. (2006) rejected FTE because, in an alternating-runs paradigm, they did not observe fixed crossing point between response-time distributions that it predicts. We replicated these findings in a cued-task paradigm that allowed us to separately examine the effects of response-to-target interval and cue-to-target interval. These results guided an extension of FTE that was tested in a further experiment and shown to be able to accommodate the effects of the interval manipulations as well as both task and cue switching. We then apply a new modeling approach to obtain direct estimates of the probability of preparation and conclude that De Jong's insights about preparation failure provide a tractable framework that can explain aspects of all of the four major task-switching phenomena identified by Monsell (2003).

  19. Beta-decay of {sup 56}Cu

    Energy Technology Data Exchange (ETDEWEB)

    Ramdhane, M.; Baumann, P.; Knipper, A.; Walter, G. [Institute de Recherches Subatomiques, 67 - Strasbourg (France); Janas, Z.; Plochocki, A. [Warsaw Univ. (Poland). Inst. of Experimental Physics; Aeystoe, J.; Dendooven, P.; Jokinen, A.; Oinonen, M.; Pentilae, H. [Jyvaeskylae Univ. (Finland); Liu, W.; Grawe, H.; Hu, Z.; Kirchner, R.; Klepper, O.; Roeckl, E. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Gorska, M. [Warsaw Univ. (Poland). Inst. of Experimental Physics]|[Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Fujita, Y. [Osaka Univ. (Japan); Brown, B.A. [Michigan State Univ., East Lansing, MI (United States)


    By measuring positrons and {beta}-delayed {gamma}-rays emitted from mass-separated sources, the decay of {sup 56}Cu(4{sup +},T{sub z}=-1,T=1) to states in the doubly-magic nucleus {sup 56}Ni was studied for the first time. The half-life of {sup 56}Cu was measured to be 78(15) ms, and four {beta}-delayed {gamma}-rays were assigned to its decay. The resulting experimental data on Fermi and Gamow-Teller strength are compared with shell-model predictions. (orig.)

  20. Correlaciones cuánticas y grafos


    López Tarrida, Antonio José


    Esta tesis doctoral trata de diversos aspectos de la teoría cuántica (TC), que abarcan desde el campo de los fundamentos de la disciplina (en particular, la búsqueda de un conjunto de principios que seleccionen y distingan a la TC en el panorama de las teorías probabilísticas generales) hasta el reino de las aplicaciones en información y computación cuánticas.   Todos los problemas que hemos abordado en nuestra investigaci&oacut...

  1. Task-free MRI predicts individual differences in brain activity during task performance. (United States)

    Tavor, I; Parker Jones, O; Mars, R B; Smith, S M; Behrens, T E; Jbabdi, S


    When asked to perform the same task, different individuals exhibit markedly different patterns of brain activity. This variability is often attributed to volatile factors, such as task strategy or compliance. We propose that individual differences in brain responses are, to a large degree, inherent to the brain and can be predicted from task-independent measurements collected at rest. Using a large set of task conditions, spanning several behavioral domains, we train a simple model that relates task-independent measurements to task activity and evaluate the model by predicting task activation maps for unseen subjects using magnetic resonance imaging. Our model can accurately predict individual differences in brain activity and highlights a coupling between brain connectivity and function that can be captured at the level of individual subjects.

  2. Scheduling optimization of task allocation in integrated manufacturing system based on task decomposition

    Institute of Scientific and Technical Information of China (English)

    Aijun Liu; Michele Pfund; John Fowler


    How to deal with the colaboration between task decomposition and task scheduling is the key problem of the integrated manufacturing system for complex products. With the development of manufacturing technology, we can probe a new way to solve this problem. Firstly, a new method for task granularity quantitative analysis is put forward, which can precisely evaluate the task granularity of complex product cooperation workflow in the integrated manufacturing system, on the above basis; this method is used to guide the coarse-grained task decomposition and recombine the sub-tasks with low cohesion coefficient. Then, a multi-objective optimieation model and an algorithm are set up for the scheduling optimization of task scheduling. Finaly, the appli-cation feasibility of the model and algorithm is ultimately vali-dated through an application case study.

  3. Analysis of Human Communication during Assembly Tasks. (United States)


    AD-A7l 43 ANALYSIS OF HUMAN COMMUNICATION DURING ASSEMBLY TASKS in1(U) CRNEGIE-MELLO UNIY PITTSBURGH PA ROBOTICS INST UNCLSSIIEDK S BARBER ET I Dur~~~~IngAbcbyTs; 7c .S:in i lSAo .0. Analysis of Human Communication During Assembly Tasks K. Suzanne Barber and Gerald J. Agin CMU-RI-TR-86-1...TYPE or REPORT & PE-Rioo CevCZaz Analysis of Human Communication During Assembly Inlterim Tasks I . PERFORMING 00RG. REPORT NUMBER 1. £UT~oOR~e) IL

  4. An approach to elemental task learning

    Energy Technology Data Exchange (ETDEWEB)

    Belmans, P


    In this article we deal with the automated learning of tasks by a robotic system through observation of a human operator. Particularly, we explain what is meant by a learning ability in autonomous robots and in teleoperation systems, where several operators and several machines may work in cooperation to perform tasks. We discuss different approaches to learning in these systems and outline the features of the models they are based upon. This leads us to choose an analytical model suited for tasks analysis. We then present the software architecture for our proposed approach and show the first results obtained on sample tests. 5 refs., 9 figs.

  5. Common mechanisms of spatial attention in memory and perception: a tactile dual-task study. (United States)

    Katus, Tobias; Andersen, Søren K; Müller, Matthias M


    Orienting attention to locations in mnemonic representations engages processes that functionally and anatomically overlap the neural circuitry guiding prospective shifts of spatial attention. The attention-based rehearsal account predicts that the requirement to withdraw attention from a memorized location impairs memory accuracy. In a dual-task study, we simultaneously presented retro-cues and pre-cues to guide spatial attention in short-term memory (STM) and perception, respectively. The spatial direction of each cue was independent of the other. The locations indicated by the combined cues could be compatible (same hand) or incompatible (opposite hands). Incompatible directional cues decreased lateralized activity in brain potentials evoked by visual cues, indicating interference in the generation of prospective attention shifts. The detection of external stimuli at the prospectively cued location was impaired when the memorized location was part of the perceptually ignored hand. The disruption of attention-based rehearsal by means of incompatible pre-cues reduced memory accuracy and affected encoding of tactile test stimuli at the retrospectively cued hand. These findings highlight the functional significance of spatial attention for spatial STM. The bidirectional interactions between both tasks demonstrate that spatial attention is a shared neural resource of a capacity-limited system that regulates information processing in internal and external stimulus representations.

  6. Superconductivity of Cu/CuOx interface formed by shock-wave pressure (United States)

    Shakhray, D. V.; Avdonin, V. V.; Palnichenko, A. V.


    A mixture of powdered Cu and CuO has been subjected to shock-wave pressure of 350 kbar with following quenching of the vacuum-encapsulated product to 77 K. The ac magnetic susceptibility measurements of the samples have revealed metastable superconductivity with Tc ≈ 19 K, characterized by glassy dynamics of the shielding currents below Tc . Comparison of the ac susceptibility and the DC magnetization measurements infers that the superconductivity arises within the granular interfacial layer formed between metallic Cu and its oxides due to the shock-wave treatment.

  7. Electrodeposition and Characterization of CuTe and Cu2Te Thin Films

    Directory of Open Access Journals (Sweden)

    Wenya He


    Full Text Available An electrodeposition method for fabrication of CuTe and Cu2Te thin films is presented. The films’ growth is based on the epitaxial electrodeposition of Cu and Te alternately with different electrochemical parameter, respectively. The deposited thin films were characterized by X-ray diffraction (XRD, field emission scanning electronic microscopy (FE-SEM with an energy dispersive X-ray (EDX analyzer, and FTIR studies. The results suggest that the epitaxial electrodeposition is an ideal method for deposition of compound semiconductor films for photoelectric applications.

  8. Synthesis, Crystal Structure, and Electroconducting Properties of a 1D Mixed-Valence Cu(I–Cu(II Coordination Polymer with a Dicyclohexyl Dithiocarbamate Ligand

    Directory of Open Access Journals (Sweden)

    Kenji Nakatani


    Full Text Available A new mixed-valence Cu(I–Cu(II 1D coordination polymer, [CuI4CuIIBr4(Cy2dtc2]n, with an infinite chain structure is synthesized by the reaction of Cu(Cy2dtc2 (Cy2dtc− = dicyclohexyl dithiocarbamate, C13H22NS2 with CuBr·S(CH32. The as-synthesized polymer consists of mononuclear copper(II units of CuII(Cy2dtc2 and tetranuclear copper(I cluster units, CuI4Br4. In the cluster unit, all the CuI ions have distorted trigonal pyramidal coordination geometries, and the CuI–CuI or CuI–CuII distances between the nearest copper ions are shorter than the sum of van der Waals radii for Cu–Cu.

  9. Taxing working memory during retrieval of emotional memories does not reduce memory accessibility when cued with reminders

    Directory of Open Access Journals (Sweden)

    Kevin eVan Schie


    Full Text Available Earlier studies have shown that when individuals recall an emotional memory while simultaneously doing a demanding dual-task (e.g., playing Tetris, mental arithmetic, making eye movements, this reduces self-reported vividness and emotionality of the memory. These effects have been found up to one week later, but have largely been confined to self-report ratings. This study examined whether this dual-tasking intervention reduces memory performance (i.e., accessibility of emotional memories. Undergraduates (N = 60 studied word-image pairs and rated the retrieved image on vividness and emotionality when cued with the word. Then they viewed the cues and recalled the images with or without making eye movements. Finally, they re-rated the images on vividness and emotionality. Additionally, fragments from images from all conditions were presented and participants identified which fragment was paired earlier with which cue. Findings showed no effect of the dual-task manipulation on self-reported ratings and latency responses. Cued recall may not have been sufficient to elicit specific and continuous target retrieval for memory blurring to occur. The study demonstrates boundaries to the effects of the dual-tasking procedure.

  10. Electrodeposited NiCu Alloy Catalysts for Glucose Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jieun; Park, Hansoo; Kim, Sookil [Chung-Ang Univ., Seoul (Korea, Republic of); Ahn, Sang Hyun; Jang, Jong Hyun [Korea Institute of Science and Technology, Seoul (Korea, Republic of)


    NiCu alloys have been suggested as potential candidates for catalysts in glucose oxidation. In this study, NiCu alloys with different compositions were prepared on a glassy carbon substrate by changing the electrodeposition potential to examine the effect of Ni/Cu ratios in alloys on catalytic activity toward glucose oxidation. Cyclic voltammetry and chronoamperometry showed that NiCu alloys had higher catalytic activity than pure Ni and Cu catalysts. Especially, Ni{sub 59}Cu{sub 41} had superior catalytic activity, which was about twice that of Ni at a given oxidation potential. X-ray analyses showed that the oxidation state of Ni in NiCu alloys was increased with the content of Cu by lattice expansion. Ni components in alloys with higher oxidation state were more effective in the oxidation of glucose.

  11. Design of Cu8Zr5-based bulk metallic glasses (United States)

    Yang, L.; Xia, J. H.; Wang, Q.; Dong, C.; Chen, L. Y.; Ou, X.; Liu, J. F.; Jiang, J. Z.; Klementiev, K.; Saksl, K.; Franz, H.; Schneider, J. R.; Gerward, L.


    Basic polyhedral clusters have been derived from intermetallic compounds at near-eutectic composition by considering a dense packing and random arrangement of atoms at shell sites. Using such building units, bulk metallic glasses can be formed. This strategy was verified in the Cu-Zr binary system, where we have demonstrated the existence of Cu8Zr5 icosahedral clusters in Cu61.8Zr38.2, Cu64Zr36, and Cu64.5Zr35.5 amorphous alloys. Furthermore, ternary bulk metallic glasses can be developed by doping the basic Cu-Zr alloy with a minority element. This hypothesis was confirmed in systems (Cu0.618Zr0.382)100-xNbx, where x =1.5 and 2.5at.%, and (Cu0.618Zr0.382)98Sn2. The present results may open a route to prepare amorphous alloys with improved glass forming ability.

  12. Fuzzy analytical hierarchy process and GIS for predictive cu -au ...

    African Journals Online (AJOL)

    Fuzzy analytical hierarchy process and GIS for predictive cu -au porphyry in ... process (Fuzzy AHP) that is the most popular multi-criteria decision-making techniques. ... for predictive Mineral prospectively mapping (MPM) for Cu -Au porphyry.

  13. Effects of Cu on the content of chlorophylls and secondary metabolites in the Cu-hyperaccumulator lichen Stereocaulon japonicum. (United States)

    Nakajima, Hiromitsu; Hara, Kojiro; Yamamoto, Yoshikazu; Itoh, Kiminori


    Understanding the relationship between Cu and Cu-hyperaccumulator lichens is important for their application in monitoring and assessing heavy metal pollution. We investigated the Cu-hyperaccumulator lichen Stereocaulon japonicum at several Cu-polluted and control sites in Japan, and found the lichen to be widely distributed. Its concentrations of Cu, chlorophylls, and secondary metabolites, chlorophyll-related indices, and absorption spectra were measured, and we observed negative effects of Cu on these concentrations and indices. For highly Cu-polluted samples (>100ppm dry weight), however, we found significant linear correlations between Cu and chlorophyll concentrations. This can be considered as the response of the photobiont in S. japonicum to Cu stress. In highly Cu-polluted samples the chlorophyll-related indices and concentration of total secondary metabolites were almost constant regardless of Cu concentration. This suggests that the increase in chlorophyll concentration with the increase in Cu concentration enhances photosynthetic productivity per unit biomass, which will allow the production of extra structure and energy for maintaining the chlorophyll-related indices under Cu stress. The relationship between the increase in chlorophyll concentration of S. japonicum and the decrease in secondary metabolite concentration of the lichen can be explained by considering the balance of carbohydrates in the lichen. We found that a spectral index A372-A394 can be a useful index of the concentrations of Cu and total secondary metabolites in S. japonicum. These findings show the adjustment of the content of chlorophylls and secondary metabolites in S. japonicum to Cu stress, and provide a better understanding of the relationship between Cu and the Cu-hyperaccumulator lichen.

  14. One-Pot Synthesis of Cu2O/Cu Self-Assembled Hollow Nanospheres with Enhanced Photocatalytic Performance

    Directory of Open Access Journals (Sweden)

    Bo Zhou


    Full Text Available Cu2O/Cu hollow spheres are prepared using one-pot template-free solvent-thermal synthesis route with (CH3COO2Cu·H2O as a precursor. With the reaction time increasing gradually from 2 h to 20 h, the morphology of the Cu2O/Cu evolves from nanoparticle to hollow nanosphere. The hollow structure is obtained when the cooling rate falls down to 0.7°C/min. And the content of Cu in the hollow spheres also can be easily controlled by adjusting the solvent-thermal synthesis time. Using photocatalytic degradation of phenol as the probe molecules under visible-light illumination, we have investigated the influence of hollow structure on the photocatalytic activity of Cu2O/Cu. The prepared hollow sphere Cu2O/Cu particles exhibited a higher photodegradation capability than nanoparticles and solid spheres. When the content of Cu lies in the range of 11–86 wt%, the samples exhibit higher photocatalytic performance, indicating that the Cu2O/Cu particles with hollow structure are promising candidates for the processing of pollutants.

  15. Effect of Cu concentration on the semi-solid deformation behavior and microstructure of Ti–Cu alloy

    Directory of Open Access Journals (Sweden)

    Yong-Nan Chen


    Full Text Available The semi-solid compressive deformation behavior of Ti–Cu alloys was investigated by Gleeble-3500 hot simulator at the deformation temperatures ranging from 1273 to 1473 K with strain rates ranging from 5×10−3 to 5×10−1 s−1. The relationship between Cu concentration and flow stress was analyzed, and the deformation apparent activation energy was also calculated. The results show that Cu concentration has significant influence on the flows’ behavior of Ti–Cu alloys, especially at high semi-solid deformation temperatures. The Ti–14Cu exhibits the highest flow stress at 1273 and 1373 K, Ti–2.5Cu alloy exhibits the highest flow stress at 1473 K, and Ti–7Cu alloy shows the lowest flow stress at all tested temperatures, which corresponds to liquid fraction caused by varied Cu concentration and the deformation temperature. The difference in microstructure suggests that the shape and distribution of Ti2Cu precipitates are significantly affected by Cu concentration. The increase in Cu concentration leads to the growth and precipitation of acicular Ti2Cu along grain boundaries at high semi-solid deformation temperatures. The deformation apparent activation energy of Ti–14Cu alloy significantly decreases from solid deformation to semi-solid deformation owing to the change in main deformation mechanism from plastic deformation of solid particles to solid particles’ slippage and rotation of grain boundaries.

  16. Insights into water coordination associated with the Cu(II)/Cu(I) electron transfer at a biomimetic Cu centre. (United States)

    Porras Gutiérrez, Ana Gabriela; Zeitouny, Joceline; Gomila, Antoine; Douziech, Bénédicte; Cosquer, Nathalie; Conan, Françoise; Reinaud, Olivia; Hapiot, Philippe; Le Mest, Yves; Lagrost, Corinne; Le Poul, Nicolas


    The coordination properties of the biomimetic complex [Cu(TMPA)(H2O)](CF3SO3)2 (TMPA = tris(2-pyridylmethyl)amine) have been investigated by electrochemistry combined with UV-Vis and EPR spectroscopy in different non-coordinating media including imidazolium-based room-temperature ionic liquids, for different water contents. The solid-state X-ray diffraction analysis of the complex shows that the cupric centre lies in a N4O coordination environment with a nearly perfect trigonal bipyramidal geometry (TBP), the water ligand being axially coordinated to Cu(II). In solution, the coordination geometry of the complex remains TBP in all media. Neither the triflate ion nor the anions of the ionic liquids were found to coordinate the copper centre. Cyclic voltammetry in all media shows that the decoordination of the water molecule occurs upon monoelectronic reduction of the Cu(II) complex. Back-coordination of the water ligand at the cuprous state can be detected by increasing the water content and/or decreasing the timescale of the experiment. Numerical simulations of the voltammograms allow the determination of kinetics and thermodynamics for the water association-dissociation mechanism. The resulting data suggest that (i) the binding/unbinding of water at the Cu(I) redox state is relatively slow and equilibrated in all media, and (ii) the binding of water at Cu(I) is somewhat faster in the ionic liquids than in the non-coordinating solvents, while the decoordination process is weakly sensitive to the nature of the solvents. These results suggest that ionic liquids favour water exchange without interfering with the coordination sphere of the metal centre. This makes them promising media for studying host-guest reactions with biomimetic complexes.

  17. When deception becomes easy: the effects of task switching and goal neglect on the truth proportion effect. (United States)

    Van Bockstaele, Bram; Wilhelm, Christine; Meijer, Ewout; Debey, Evelyne; Verschuere, Bruno


    Lying is typically more cognitively demanding than truth telling. Yet, recent cognitive models of lying propose that lying can be just as easy as truth telling, depending on contextual factors. In line with this idea, research has shown that the cognitive cost of deception decreases when people frequently respond deceptively, while it increases when people rarely respond deceptively (i.e., the truth proportion effect). In the present study, we investigated two possible underlying mechanisms of the truth proportion effect. In Experiment 1 (N = 121), we controlled for the impact of switch costs by keeping the number of switches between deceptive and truthful responses constant. We found that people who often responded deceptively made fewer errors when responding deceptively than people who only occasionally responded deceptively, replicating the truth proportion effect. Thus, while the truth proportion effect in earlier studies may be partially driven by the cost of switching between truthful and deceptive responses, we still found evidence for the truth proportion effect while controlling for switch costs. In Experiment 2 (N = 68), we assessed whether the truth proportion effect is influenced by goal neglect. According to this view, the truth proportion effect should be reduced if participants are cued to maintain the task goals, while it should be larger when participants are allowed to neglect the task goals. In line with this hypothesis, we found a smaller truth proportion effect when participants were cued with the task goals compared to when they were not cued. This study shows that the truth proportion effect is influenced by goal neglect, implying that frequent deceptive responding strengthens the goal of responding deceptively. Our findings imply that the accuracy of lie detection tests could be increased by using a majority of truth-items (i.e., induce the truth proportion effect), and that the truth proportion effect should be maximized by (1) increasing

  18. Decision Making System for Operative Tasks


    Shakah, G.; Krasnoproshin, V. V.; Valvachev, A. N.


    Actual problems of construction of computer systems for operative tasks of decision making are considered. possibilities of solving the problems on the basis of the theory of active systems (tas) are investigated.

  19. Pyramid Lake Task Force : Final report (United States)

    US Fish and Wildlife Service, Department of the Interior — The Pyramid Lake Task Force was created to address Pyramid Lake’s recession and recommend possible solutions that would consider both the needs for preserving the...

  20. Communicative Tasks and the Language Curriculum. (United States)

    Nunan, David


    Reviews the conceptual, curricular, and empirical bases of task-based language teaching and suggests future trends, concluding that the conceptual and empirical bases need to be extended both substantively and methodologically. (38 references) (CB)

  1. Communicative Tasks and the Language Curriculum. (United States)

    Nunan, David


    Reviews the conceptual, curricular, and empirical bases of task-based language teaching and suggests future trends, concluding that the conceptual and empirical bases need to be extended both substantively and methodologically. (38 references) (CB)

  2. A Study on Mental Tasks Discriminative Power (United States)

    Dobrea, Dan Marius; Dobrea, Monica-Claudia

    The present study was done as part of a more complex project whose final aim is to design and implement an autonomic self-organizing system, mentally commanded by an user giving one of the 4 possible commands: forth, back, left, right. For this, we used the most studied method for designing non-invasive brain-computer interface (BCI), namely, the electroencephalogram (EEG) signals acquired during mental tasks. To command, in real-time, the system requires very discriminative mental tasks to be used to trigger the corresponding device commands. The novelty of our paper consists in revealing the great importance the preliminary selecting process of subject-specific set of tasks plays within the implementation of any particular BCI application. In this idea, our research focuses on an extensive analysis of twelve mental tasks; the processing and classification approaches used by us are classical ones.

  3. An ergonomic task analysis of spinal anaesthesia.

    LENUS (Irish Health Repository)

    Ajmal, Muhammad


    Ergonomics is the study of physical interaction between humans and their working environment. The objective of this study was to characterize the performance of spinal anaesthesia in an acute hospital setting, applying ergonomic task analysis.

  4. Compositional Memory Systems for Multimedia Communicating Tasks

    CERN Document Server

    Molnos, A M; Cotofana, S D; Van Eijndhoven, J T J


    Conventional cache models are not suited for real-time parallel processing because tasks may flush each other's data out of the cache in an unpredictable manner. In this way the system is not compositional so the overall performance is difficult to predict and the integration of new tasks expensive. This paper proposes a new method that imposes compositionality to the system?s performance and makes different memory hierarchy optimizations possible for multimedia communicating tasks when running on embedded multiprocessor architectures. The method is based on a cache allocation strategy that assigns sets of the unified cache exclusively to tasks and to the communication buffers. We also analytically formulate the problem and describe a method to compute the cache partitioning ratio for optimizing the throughput and the consumed power. When applied to a multiprocessor with memory hierarchy our technique delivers also performance gain. Compared to the shared cache case, for an application consisting of two jpeg ...

  5. Variance components in discrete force production tasks. (United States)

    Varadhan, S K M; Zatsiorsky, Vladimir M; Latash, Mark L


    The study addresses the relationships between task parameters and two components of variance, "good" and "bad", during multi-finger accurate force production. The variance components are defined in the space of commands to the fingers (finger modes) and refer to variance that does ("bad") and does not ("good") affect total force. Based on an earlier study of cyclic force production, we hypothesized that speeding-up an accurate force production task would be accompanied by a drop in the regression coefficient linking the "bad" variance and force rate such that variance of the total force remains largely unaffected. We also explored changes in parameters of anticipatory synergy adjustments with speeding-up the task. The subjects produced accurate ramps of total force over different times and in different directions (force-up and force-down) while pressing with the four fingers of the right hand on individual force sensors. The two variance components were quantified, and their normalized difference was used as an index of a total force stabilizing synergy. "Good" variance scaled linearly with force magnitude and did not depend on force rate. "Bad" variance scaled linearly with force rate within each task, and the scaling coefficient did not change across tasks with different ramp times. As a result, a drop in force ramp time was associated with an increase in total force variance, unlike the results of the study of cyclic tasks. The synergy index dropped 100-200 ms prior to the first visible signs of force change. The timing and magnitude of these anticipatory synergy adjustments did not depend on the ramp time. Analysis of the data within an earlier model has shown adjustments in the variance of a timing parameter, although these adjustments were not as pronounced as in the earlier study of cyclic force production. Overall, we observed qualitative differences between the discrete and cyclic force production tasks: Speeding-up the cyclic tasks was associated with

  6. Mesoscale organization of CuO nanoslices: Formation of sphere

    Indian Academy of Sciences (India)

    Jun Wang; Shunxiao Zhang; Zhanshuang Li; Jia You; Piaoping Yang; Xiaoyan Jing; Milin Zhang


    The nanocrystalline CuO powders were prepared by precipitation method using Cu(NO$_{3})_{2}$ as copper raw material, water and ethanol as dispersants, and NaOH and ammonia solution as precipitates. The structure, particle size and morphology of resulting CuO powders were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mechanism of CuO formation was discussed.

  7. Monitoring supports performance in a dual-task paradigm involving a risky decision-making task and a working memory task

    Directory of Open Access Journals (Sweden)

    Bettina eGathmann


    Full Text Available Performing two cognitively demanding tasks at the same time is known to decrease performance. The current study investigates the underlying executive functions of a dual-tasking situation involving the simultaneous performance of decision making under explicit risk and a working memory task. It is suggested that making a decision and performing a working memory task at the same time should particularly require monitoring - an executive control process supervising behavior and the state of processing on two tasks. To test the role of a supervisory/monitoring function in such a dual-tasking situation we investigated 122 participants with the Game of Dice Task plus 2-back task (GDT plus 2-back task. This dual task requires participants to make decisions under risk and to perform a 2-back working memory task at the same time. Furthermore, a task measuring a set of several executive functions gathered in the term concept formation (Modified Card Sorting Test, MCST and the newly developed Balanced Switching Task (BST, measuring monitoring in particular, were used. The results demonstrate that concept formation and monitoring are involved in the simultaneous performance of decision making under risk and a working memory task. In particular, the mediation analysis revealed that BST performance partially mediates the influence of MCST performance on the GDT plus 2-back task. These findings suggest that monitoring is one important subfunction for superior performance in a dual-tasking situation including decision making under risk and a working memory task.

  8. An Architecture for Robot Assemblt Task Planning

    DEFF Research Database (Denmark)

    Sun, Hongyan


    This paper discusses an integrated robot assembly task planning system architecture. In such an integrated system, the robot motion commands produced from the planning system can be validated before done-loading for actual execution.......This paper discusses an integrated robot assembly task planning system architecture. In such an integrated system, the robot motion commands produced from the planning system can be validated before done-loading for actual execution....

  9. Task sequencing for autonomous robotic vacuum cleaners (United States)

    Gorbenko, Anna; Popov, Vladimir


    Various planning problems for robotic systems are of considerable interest. One of such problems is the problem of task sequencing. In this paper, we consider the problem of task sequencing for autonomous vacuum floor cleaning robots. We consider a graph model for the problem. We propose an efficient approach to solve the problem. In particular, we use an explicit reduction from the decision version of the problem to the satisfiability problem. We present the results of computational experiments for different satisfiability algorithms.

  10. Malware Task Identification: A Data Driven Approach


    Nunes, Eric; Buto, Casey; Shakarian, Paulo; Lebiere, Christian; Bennati, Stefano; THOMSON, ROBERT; Jaenisch, Holger


    Identifying the tasks a given piece of malware was designed to perform (e.g. logging keystrokes, recording video, establishing remote access, etc.) is a difficult and time-consuming operation that is largely human-driven in practice. In this paper, we present an automated method to identify malware tasks. Using two different malware collections, we explore various circumstances for each - including cases where the training data differs significantly from test; where the malware being evaluate...

  11. Heuristic Based Task Scheduling In Grid

    Directory of Open Access Journals (Sweden)

    Manpreet Singh


    Full Text Available Grid computing is concerned with coordinated resource sharing and problem solving in dynamic, multi-institutional virtual organizations. Efficient scheduling of complex applications in a grid environment reveals several challenges due to its high heterogeneity, dynamic behavior and space shared utilization. Objectives of scheduling algorithms are increase in system throughput, efficiency and reduction in task completion time. The main focus of this paper is to highlight the merits of resource and task selection technique based on certain heuristics.

  12. A change of task prolongs early processes: evidence from ERPs in lexical tasks. (United States)

    Elchlepp, Heike; Lavric, Aureliu; Monsell, Stephen


    Switching tasks costs time. Allowing time to prepare reduces the cost, but usually leaves an irreducible "residual cost." Most accounts of this residual cost locate it within the response-selection stage of processing. To determine which processing stage is affected, we measured event-related potentials (ERPs) as participants performed a reading task or a perceptual judgment task, and examined the effect of a task switch on early markers of lexical processing. A task cue preceding a string of blue and red letters instructed the participant either to read the letter string (for a semantic classification in Experiment 1, and a lexical decision in Experiment 2) or to judge the symmetry of its color pattern. In Experiment 1, having to switch to the reading task delayed the evolution of the effect of word frequency on the reading task ERP by a substantial fraction of the effect on reaction time (RT). In Experiment 2, a task switch delayed the onset of the effect of lexical status on the ERP by about the same extent that it prolonged the RT. These effects indicate an early locus of (most of) the residual switch cost: We propose that this reflects a form of task-related attentional inertia. Other findings have implications for the automaticity of lexical access: Effects of frequency, lexicality, and orthographic familiarity on ERPs in the symmetry task indicated involuntary, but attenuated, orthographic and lexical processing even when attention was focused on a nonlexical property.

  13. Strategic Adaptation to Task Characteristics, Incentives, and Individual Differences in Dual-Tasking.

    Directory of Open Access Journals (Sweden)

    Christian P Janssen

    Full Text Available We investigate how good people are at multitasking by comparing behavior to a prediction of the optimal strategy for dividing attention between two concurrent tasks. In our experiment, 24 participants had to interleave entering digits on a keyboard with controlling a randomly moving cursor with a joystick. The difficulty of the tracking task was systematically varied as a within-subjects factor. Participants were also exposed to different explicit reward functions that varied the relative importance of the tracking task relative to the typing task (between-subjects. Results demonstrate that these changes in task characteristics and monetary incentives, together with individual differences in typing ability, influenced how participants choose to interleave tasks. This change in strategy then affected their performance on each task. A computational cognitive model was used to predict performance for a wide set of alternative strategies for how participants might have possibly interleaved tasks. This allowed for predictions of optimal performance to be derived, given the constraints placed on performance by the task and cognition. A comparison of human behavior with the predicted optimal strategy shows that participants behaved near optimally. Our findings have implications for the design and evaluation of technology for multitasking situations, as consideration should be given to the characteristics of the task, but also to how different users might use technology depending on their individual characteristics and their priorities.

  14. Coordination equilibria in the complex formation of guanylurea with CuII: Formation and stability of binary CuII-guanylurea and ternary CuII-guanylurea-glycinate complexes

    Indian Academy of Sciences (India)

    Tannistha Roy Barman; G N Mukherjee


    Combined pH-metric and spectrophotometric investigations on the complex formation equilibria of CuII with guanylurea (H$_{2}^{1}$NC(=O) 2NH.C(=3NH) 4NH2), hereafter, GuH, in the absence and in the presence of glycine (GlyH), in aqueous solution indicates variety of binary and mixed-ligand complexes: Cu(Gu)+, Cu(Gu)(OH); Cu(Gu)2, Cu(Gu-H)(Gu)-, Cu(Gu-H)$_{2}^{2-}$, Cu(Gu-H)(Gu-2H)3-; Cu(Gly)+, Cu(Gly) (OH); Cu(Gly)(Gu); Cu(Gly)(Gu-H)-, Cu(Gly)(Gu-2H)2-; (Gly)Cu(Gu)Cu(Gly)+, (Gly)Cu(Gu-H)Cu(Gly) and (Gly)Cu(Gu-2H)Cu(Gly)-. At pH < 6, guanylurea anion (Gu-) acts as a [(C=O), 3N-] or [=1NH, 3N-] bidentate ligand and above pH 7 it is transformed through a coordination equilibrium into a (=1N-, =3N-) bidentate ligand, similar to biguanide dianion. Occurrence of dinuclear complex species, (Gly) Cu(Gu)Cu(Gly)+, in the complexation equilibria, indicates bridging double bidentate [(1NH2, 3N-), (C=O, 4NH2)] and/or [(1NH2, 4NH2), (C=O, 3N-)] chelation by Gu- ion in an isomeric equilibrium. Above pH 6.5, the dinuclear complex decomposes mostly to the mononuclear species, Cu(Gly)(OH) and Cu(Gu)(OH) and only partly deprotonates to (Gly)Cu(Gu-H)Cu(Gly) and (Gly)Cu(Gu-2H)Cu(Gly)-. Electronic spectral shifts, with change of pH have been correlated with the possible modes of coordination of guanylurea species.

  15. Cu(II) promotes amyloid pore formation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hangyu, E-mail: [Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907 (United States); Rochet, Jean-Christophe [Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907 (United States); Stanciu, Lia A. [Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907 (United States); School of Materials Engineering, Purdue University, West Lafayette, IN 47907 (United States)


    The aggregation of α-synuclein is associated with dopamine neuron death in Parkinson's disease. There is controversy in the field over the question of which species of the aggregates, fibrils or protofibrils, are toxic. Moreover, compelling evidence suggested the exposure to heavy metals to be a risk of PD. Nevertheless, the mechanism of metal ions in promoting PD remains unclear. In this research, we investigated the structural basis of Cu(II) induced aggregation of α-synuclein. Using transmission electron microscopy experiments, Cu(II) was found to promote in vitro aggregation of α-synuclein by facilitating annular protofibril formation rather than fibril formation. Furthermore, neuroprotective baicalein disaggregated annular protofibrils accompanied by considerable decrease of β-sheet content. These results strongly support the hypothesis that annular protofibrils are the toxic species, rather than fibrils, thereby inspiring us to search novel therapeutic strategies for the suppression of the toxic annular protofibril formation. - Highlights: • Cu(II) promoted the annular protofibril formation of α-synuclein in vitro. • Cu(II) postponed the in vitro fibrillization of α-synuclein. • Neuroprotective baicalein disaggregated annular protofibrils.

  16. Superconductivity in Zigzag CuO Chains

    Energy Technology Data Exchange (ETDEWEB)

    Berg, E.


    Superconductivity has recently been discovered in Pr{sub 2}Ba{sub 4}Cu{sub 7}O{sub 15-{delta}} with a maximum T{sub c} of about 15K. Since the CuO planes in this material are believed to be insulating, it has been proposed that the superconductivity occurs in the double (or zigzag) CuO chain layer. On phenomenological grounds we propose a theoretical interpretation of the experimental results in terms of a new phase for the zigzag chain, labelled by C{sub 1}S{sub 3/2}. This phase has a gap in the relative charge mode and a partial gap in the relative spin mode. It has gapless uniform charge and spin excitations and can have a divergent superconducting susceptibility, even for repulsive interactions. A microscopic model for the zigzag CuO chain is proposed, and on the basis of density matrix renormalization group (DMRG) and bosonization studies, we adduce evidence that supports our proposal.

  17. Surface structure of AU3Cu(001)

    DEFF Research Database (Denmark)

    Eckstein, G.A.; Maupai, S.; Dakkouri, A.S.


    The surface morphology, composition, and structure of Au3Cu(001) as determined by scanning tunneling microscopy and surface x-ray diffraction are presented. Atomic resolution STM images reveal distinctive geometric features. The analysis of the surface x-ray diffraction data provides clear evidence...... for the surface structure. [S0163-1829(99)04535-X]....

  18. Horizontal plane head stabilization during locomotor tasks. (United States)

    Cromwell, R L; Newton, R A; Carlton, L G


    Frequency characteristics of head stabilization were examined during locomotor tasks in healthy young adults(N = 8) who performed normal walking and 3 walking tasks designed to produce perturbations primarily in the horizontal plane. In the 3 walking tasks, the arms moved in phase with leg movement, with abnormally large amplitude, and at twice the frequency of leg movement. Head-in-space angular velocity was examined at the predominant frequencies of trunk motion. Head movements in space occurred at low frequencies ( 4.0 Hz) when the arms moved at twice the frequency of the legs. Head stabilization strategies were determined from head-on-trunk with respect to trunk frequency profiles derived from angular velocity data. During natural walking at low frequencies (head-on-trunk movement was less than trunk movement. At frequencies 3.0 Hz or greater, equal and opposite compensatory movement ensured head stability. When arm swing was altered, compensatory movement guaranteed head stability at all frequencies. Head stabilization was successful for frequencies up to 10.0 Hz during locomotor tasks. Maintaining head stability at high frequencies during voluntary tasks suggests that participants used feedforward mechanisms to coordinate head and trunk movements. Maintenance of head stability during dynamic tasks allows optimal conditions for vestibulo-ocular reflex function.

  19. Reverse control for humanoid robot task recognition. (United States)

    Hak, Sovannara; Mansard, Nicolas; Stasse, Olivier; Laumond, Jean Paul


    Efficient methods to perform motion recognition have been developed using statistical tools. Those methods rely on primitive learning in a suitable space, for example, the latent space of the joint angle and/or adequate task spaces. Learned primitives are often sequential: A motion is segmented according to the time axis. When working with a humanoid robot, a motion can be decomposed into parallel subtasks. For example, in a waiter scenario, the robot has to keep some plates horizontal with one of its arms while placing a plate on the table with its free hand. Recognition can thus not be limited to one task per consecutive segment of time. The method presented in this paper takes advantage of the knowledge of what tasks the robot is able to do and how the motion is generated from this set of known controllers, to perform a reverse engineering of an observed motion. This analysis is intended to recognize parallel tasks that have been used to generate a motion. The method relies on the task-function formalism and the projection operation into the null space of a task to decouple the controllers. The approach is successfully applied on a real robot to disambiguate motion in different scenarios where two motions look similar but have different purposes.

  20. Operations and Performance of RHIC as a Cu-Cu Collider

    CERN Document Server

    Pilat, Fulvia Caterina; Bai, Mei; Barton, Donald; Beebe-Wang, Joanne; Blaskiewicz, Michael; Brennan, Joseph M; Bruno, Donald; Cameron, Peter; Connolly, Roger; De Long, Joseph; Drees, Angelika; Fischer, Wolfram; Ganetis, George; Gardner, Chris J; Glenn, Joseph; Harvey, Margaret; Hayes, Thomas; Hseuh Hsiao Chaun; Huang, Haixin; Ingrassia, Peter; Iriso, Ubaldo; Lee, Roger C; Litvinenko, Vladimir N; Luo, Yun; MacKay, William W; Marr, Gregory J; Marusic, Al; Michnoff, Robert; Montag, Christoph; Morris, John; Nicoletti, Tony; Oerter, Brian; Ptitsyn, Vadim; Roser, Thomas; Russo, Thomas; Sandberg, Jon; Satogata, Todd; Schultheiss, Carl; Tepikian, Steven; Tomas, Rogelio; Trbojevic, Dejan; Tsoupas, Nicholaos; Tuozzolo, Joseph; Vetter, Kurt; Zaltsman, Alex; Zeno, Keith; Zhang, S Y; Zhang, Wu


    The 5th year of RHIC operations, started in November 2004 and expected to last till June 2005, consists of a physics run with Cu-Cu collisions at 100 GeV/u followed by one with polarized protons at 100 GeV. We will address here overall performance of the RHIC complex used for the first time as a Cu-Cu collider, and compare it with previous operational experience with Au, PP and asymmetric d-Au collisions. We will also discuss operational improvements, such as a ?* squeeze to 85cm in the high luminosity interaction regions from the design value of 1m, system improvements and machine performance limitations, such as vacuum pressure rise, intra-beam scattering, and beam beam interaction.

  1. Pressure dependence of the Cu magnetic order in RBa2Cu3O6+x (United States)

    Lynn, J. W.; Li, W.-H.; Trevino, S. F.; Fisk, Z.


    Neutron-diffraction measurements have been carried out as a function of hydrostatic pressure to study the magnetic order of the Cu spins in NdBa2Cu3O6.35 and NdBa2Cu3O6.1. In the high-temperature phase, where the Cu planes order antiferromagnetically, we find that the Néel temperature TN1 is very strongly dependent on pressure, increasing at the rate of ~23 K/kbar. We attribute this phenomenal sensitivity to the two-dimensional-like behavior of this magnetic system. In the low-temperature phase, which is associated with magnetic ordering of the chains, only a small change in the ordering temperature TN2 is observed.

  2. Strength and reliability of low temperature transient liquid phase bonded Cu-Sn-Cu interconnects

    DEFF Research Database (Denmark)

    Brincker, Mads; Söhl, Stefan; Eisele, Ronald


    as a potential technology that could enable the realization of stacks with better thermal performance and reliability than those can be achieved using conventional soldering techniques. Low temperature TLP bonded CuSnCu samples are fabricated, and the strength of the achieved bonds is measured by shear testing......As power electronic devices have tendencies to operate at higher temperatures and current densities, the demand for reliable and efficient packaging technologies are ever increasing. This paper reports the studies on application of transient liquid phase (TLP) bonding of CuSnCu systems...... for achieving a strong and high temperature resistant bond. Finally, initial results from a thermal cycling test are presented and it is concluded that the achieved TLP bonding is a promising candidate for the fabrication of reliable interconnects in power electronics....

  3. Metastable Demixing of Supercooled Cu-Co and Cu-Fe Alloys in an Oxide Flux (United States)

    Li, D.; Robinson, M. B.; Rathz, T. J.; Williams, G.


    A systematic study on the liquid separation in supercooled Cu-Co and Cu-Fe alloys was performed using a melt fluxing which permits high supercooling to be achieved. Moreover, this method renders it possible to directly measure binodal temperatures and establish metastable liquid miscibility gap (LMG). All phase-separated samples at compositions ranging from 10 to 80 wt pct Co or to 83 wt pct Fe were found to exhibit droplet-shaped morphologies, in spite of various droplet distributions. Uniformly dispersed microstructures were obtained as the minority component was less than 20 vol.%; while beyond this percentage, serious coarsening was brought about. Calculations of the miscibility gap in the Cu-Co system and Stokes movement velocity of Co and Fe droplets in Cu matrix were made to analyze the experimental results.

  4. Order twins in (111)-evaporated thin films of CuAu I. [Cu-Au

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, R.; Broitman, E. (Dept. de Fisica, Univ. de Buenos Aires (Argentina)); Harriague, S.; Terlisky, S. (Comision Nacional de Energia Atomica, Buenos Aires (Argentina))


    The structure of evaporated CuAu I films in (111) orientation was studied by electron transmission and diffraction microscopy. The single-crystal films of Cu-Au alloy were prepared by vacuum evaporation and CuAu I ordered alloy was obtained by heating the disordered f.c.c. alloy to a temperature of 350deg C for 1 h. The electron micrograph revealed the presence of an intricate pattern of antiphase domain boundaries and the presence of twin lamellae. No microtwinning was observed. The CuAu I films exhibit a complex diffraction pattern. The geometry of the expected (111) reciprocal lattice plane has been calculated and described in detail. Extra reflections were identified as {l brace}101{r brace} twin spots and double-diffraction spots which originated from the twins. (orig.).

  5. Controlled synthesis of CuO nanostructures on Cu foil, rod and grid

    Energy Technology Data Exchange (ETDEWEB)

    Vanithakumari, S.C.; Shinde, S.L. [Materials Research Centre, Indian Institute of Science, C.V. Raman Avenue, Malleswaram, Bangalore 560012, Karnataka (India); Nanda, K.K., E-mail: [Materials Research Centre, Indian Institute of Science, C.V. Raman Avenue, Malleswaram, Bangalore 560012, Karnataka (India)


    CuO nanowires are synthesized by heating Cu foil, rod and grid in ambient without employing a catalyst or gas flow at temperatures ranging from 400 to 800 deg. C for a duration of 1-12 h. Scanning electron microscopy (SEM) investigation reveals the formation of nanowires. The structure, morphology and phase of the as-synthesized nanowires are analyzed by various techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). It is found that these nanowires are composed of CuO phase and the underlying film is of Cu{sub 2}O. A systematic study is carried out to find the possibilities for the transformation of one phase to another completely. A possible growth mechanism for the nanowires is also discussed.


    Energy Technology Data Exchange (ETDEWEB)



    The 5th year of RHIC operations, started in November 2004 and expected to last till June 2005, consists of a physics run with Cu-Cu collisions at 100 GeV/u followed by one with polarized protons (pp) at 100 GeV [l]. We will address here the overall performance of the RHIC complex used for the first time as a Cu-Cu collider, and compare it with previous operational experience with Au, PP and asymmetric d-Au collisions. We will also discuss operational improvements, such as a {beta}* squeeze to 85cm in the high luminosity interaction regions from the design value of 1m, system improvements, machine performance and limitations, and address reliability and uptime issues.

  7. Structural and magnetic properties of epitaxial Fe/Cu multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Y. E-mail:; Nakanishi, Y.; Yoshimoto, N.; Yamaguchi, A.; Nakamura, M.; Yoshizawa, M


    We have grown FCC-Fe/Cu multilayers by molecular beam epitaxy method. The structural and magnetic properties were studied by RHEED, XRD and magnetoresistance measurement (MR). The RHEED images confirmed that Fe/Cu multilayers were epitaxially grown on Cu(1 0 0). Furthermore, a clear negative MR was observed. The buffer layer condition for MR effect will be discussed.

  8. Ferromagnetism in CuO-ZnO multilayers (United States)

    Chandran, Sudakar; Kirby, B. J.; Padmanabhan, K.; Lawes, G.; Naik, R.; Kumar, Sanjiv; Naik, V. M.


    The magnetic properties of CuO-ZnO heterostructures are examined to elucidate the origin of the ferromagnetic signature in Cu doped ZnO. The CuO and ZnO layer thickness varied from 15 nm to 350 nm, and we observed no significant diffusion of either Cu^2+ in the ZnO layers or of Zn^2+ in the CuO layers using Rutherford backscattering spectrometry. Bulk magnetization measurements established that the multilayers exhibit a ferromagnetic moment at room temperature, with a saturation magnetization (˜2-5 emu/cc of CuO) that depends on the CuO size, but not the CuO-ZnO interfacial area. Polarized neutron reflection studies suggest that the ferromagnetism arises from the CuO layers, and not from the interdiffusion of CuO and ZnO. These results indicate that the ferromagnetism in these multicomponent structures arises from the uncompensated surface spins of CuO nanoparticles in the layer rather than from regions of interdiffusing ZnO and CuO.

  9. Two different cationic positions in Cu-SSZ-13? (United States)

    Hun Kwak, Ja; Zhu, Haiyang; Lee, Jong H; Peden, Charles H F; Szanyi, János


    H(2)-TPR and FTIR were used to characterize the nature of the Cu ions present in the Cu-SSZ-13 zeolite at different ion exchange levels. The results obtained are consistent with the presence of Cu ions at two distinct cationic positions in the SSZ-13 framework.

  10. Two different cationic positions in Cu-SSZ-13?

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Ja Hun; Zhu, Haiyang; Lee, Jong H.; Peden, Charles HF; Szanyi, Janos


    H2-TPR and FTIR were used to characterize the Cu ions present in Cu-SSZ-13 zeolite at different ion exchange levels. The results obtained are consistent with the presence of Cu ions in two distinct cationic positions of the SSZ-13 framework.

  11. Microstructure of directionally solidified Cu-Cr composites

    Institute of Scientific and Technical Information of China (English)

    毕晓勤; 李金山; 胡锐; 耿兴国; 朱琦; 傅恒志


    Cu-Cr composites were prepared by self-made directional solidification equipment with the high temperature gradient and double-zone heating. The microstructural evolution was investigated during the directional solidification with the different solidification rate for Cu-1.0%Cr, Cu-1.7%Cr and Cu-5.6%Cr alloys, respectively. It is shown that for the hypoeutectic Cu-1.0%Cr alloy, the general microstructures consist of primary α(Cu) phase and the rod-like or needle-like (α+β) eutectics, and for the hypereutectic Cu-1. 7%Cr and Cu-5.6%Cr alloys, α(Cu)phase, primary β(Cr) phase and (α+β) eutectics coexist. With the increase of the solidification rate, the morphology evolution of every phase is that, 1st cellular(dendrite) of α(Cu) phase thins and cellular(dendrite) spacing shortens gradually, (α+β) eutectics set in α(Cu) cellular or dendrite, and primary β(Cr) phase distributes unevenly on α (Cu) matrix, whose morphology undergoes the change from dendrite to particle.

  12. Electromigration of Sn-3Ag-0.5Cu and Sn-3Ag-0.5Cu-0.5Ce-0.2Zn solder joints with Au/Ni(P)/Cu and Ag/Cu pads

    Energy Technology Data Exchange (ETDEWEB)

    Lin, H.-J., E-mail: [Institute of Materials Science and Engineering, National Taiwan University, 1 Roosevelt St. Sec. 4, Taipei 106, Taiwan (China); Industrial Technology Research Institute, Mechanical and Systems Research Laboratories, Hsinchu 310, Taiwan (China); Lin, J.-S., E-mail: [Industrial Technology Research Institute, Mechanical and Systems Research Laboratories, Hsinchu 310, Taiwan (China); Department of Mechanical Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan); Chuang, T.-H., E-mail: [Institute of Materials Science and Engineering, National Taiwan University, 1 Roosevelt St. Sec. 4, Taipei 106, Taiwan (China)


    It has previously been established that adding 0.2 wt.% Zn into a Sn-3Ag-0.5Cu-0.5Ce alloy improves the mechanical properties and eliminates the problem of rapid whisker growth. However, no detailed studies have been conducted on electromigration behavior of Sn-3Ag-0.5Cu-0.5Ce-0.2Zn alloy. The electromigration damage in solder joints of Sn-3Ag-0.5Cu and Sn-3Ag-0.5Cu-0.5Ce-0.2Zn with Ag/Cu pads and Au/Ni(P)/Cu pads was studied after current stressing at room temperature with an average current density of 3.1 x 10{sup 4} A/cm{sup 2}. With additions of 0.5 wt.% Ce and 0.2 wt.% Zn, the electromigration processes of Sn-Ag-Cu solder joints were accelerated due to refinement of the solder matrix when joint temperature was around 80 deg. C. Since Ni is more resistant than Cu to diffusion driven by electron flow, solder joints of both alloys (Sn-3Ag-0.5Cu and Sn-3Ag-0.5Cu-0.5Ce-0.2Zn) with Au/Ni(P)/Cu pads possess longer current-stressing lifetimes than those with Ag/Cu pads.

  13. Conduction behavior conversion for Cu-doped ZnS/n-type Si devices with different Cu contents (United States)

    Ni, Wei-Shih; Lin, Yow-Jon


    Currents through Cu-doped ZnS (ZnCuS)/n-type Si structures were studied. The electrical conduction investigations suggest that the carrier transport behavior is governed by the Poole-Frenkel emission for ZnCuS/n-type Si devices having the low Cu concentration. However, the carrier transport behavior is governed by the thermionic emission for ZnCuS/n-type Si devices having the high Cu concentration. The photoluminescence result revealed that sulfur vacancy ( V S) is the origin of conduction behavior conversion. It is shown that the increased Cu concentration leads to the reduced formation probability of V S. The dependence of V S on the film composition was identified for providing a guide to control the current transport behavior of ZnCuS/n-type Si devices.

  14. Using electrophysiology to demonstrate that cuing affects long-term memory storage over the short term (United States)

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


    As researchers who study working memory, we often assume that participants keep a representation of an object in working memory when we present a cue that indicates that object will be tested in a couple of seconds. This intuitively accounts for how well people can remember a cued object relative to their memory for that same object presented without a cue. However, it is possible that this superior memory does not purely reflect storage of the cued object in working memory. We tested the hypothesis that cued presented during a stream of objects, followed by a short retention interval and immediate memory test, change how information is handled by long-term memory. We tested this hypothesis using a family of frontal event-related potentials (ERPs) believed to reflect long-term memory storage. We found that these frontal indices of long-term memory were sensitive to the task relevance of objects signaled by auditory cues, even when objects repeat frequently such that proactive interference was high. Our findings indicate the problematic nature of assuming process purity in the study of working memory, and demonstrate how frequent stimulus repetitions fail to isolate the role of working memory mechanisms. PMID:25604772

  15. Concave Cu-Pd bimetallic nanocrystals: Ligand-based Co-reduction and mechanistic study

    Institute of Scientific and Technical Information of China (English)

    Lan Zhang[1; Hongyang Su[1; Mei Sun[1; Youcheng Wang[1; Wenlong Wu[1; Taekyung Yu[2; Jie Zeng[1


    The synthesis of highly uniform alloy nanocrystals with a concave feature is desirable for applications in catalysis but is an arduous task. This article proposes an initiative protocol for the fabrication of novel Cu-Pd alloy nanocrystals, wherein the volume of decylamine (DA) in the reaction system was found to greatly influence the formation of different morphologies, including the tetrahedron (TH), concave tetrahedron (CTH), rhombohedral-tetrapod (RTP), and tetrapod (TP). The alloy structure of the products arises from the coordination interaction between the DA and metal ions, which affects the reduction potential of Cu and Pd species, and thus yields co-reduction. Other reaction parameters, such as the type of ligand, amount of reductant, and temperature, were also altered to study the growth mechanism, yielding consistent conclusions in the diffusion-controlled regime. As a catalyst, 48-nm Cu-Pd concave tetrahedral nanocrystals were highly active for the hydrogenation of 3-nitrostyrene and exhibited 〉99.9% chemoselectivity to C=C instead of-NO2.

  16. Dissolution behavior of Cu in Cu-Ag and Cu-P brazing alloys using weld brazing%溶解钎焊时Cu在Cu-Ag及Cu-P合金钎料中的溶解行为

    Institute of Scientific and Technical Information of China (English)

    李一楠; 王长文; 彭子龙; 闫久春; 刘雪松


    研究溶解钎焊条件下母材Cu在Cu-Ag及Cu-P合金钎料中的溶解行为.测量了在800~920℃的温度范围内铜箔在Cu-P和Cu-Ag合金中的溶解厚度.推导并计算出Cu在这两种合金钎料中的溶解速度常数存在如下关系:kCu-p(T)=10kCu-A(T).结果表明,采用溶解钎焊工艺时在相同条件下液态Cu-P合金对母材Cu的溶解量大于Cu-Ag合金的.由于溶解钎焊工艺在一个热循环内具有反应时间短和温度变化快的特点,因此Cu在液态钎料中快的溶解反应速度是实现溶解钎焊的根本原因.同时,P元素与Ag元素相比具有加速溶解母材的作用,是实现溶解钎焊必不可少的合金元素.研究了合金元素的添加对焊接接头力学性能的影响,提出了获得良好力学性能的钎料成分设计原则.%The dissolution behavior of base metal Cu in the Cu-Ag and Cu-P brazing alloys using weld brazing was researched.The thickness loss of Cu foil in contact with Cu-P and Cu-Ag alloys at 800-920 ℃ was measured.And the dissolution rate constants in both alloys were calculated as the following relation:kcu-p(T)=1 0kCu.Ag(T),which explains the special phenomenon that the dissolving amount of copper in Cu-P liquid alloys is larger than that in Cu-Ag alloys under the same condition.As weld brazing has its own characteristics of short reaction time and quick temperature variation in one thermal cycle,the quick dissolution rate of copper in filler metals is the main reason to achieve weld brazing.It can be concluded that element P is indispensable in filler metals compared with element Ag as the function of accelerating dissolution during weld brazing.Finally,the influences of the addition of alloy element on mechanical performance of the welding joints were studied and the design principles of filler metals for weld brazing were proposed to achieve good mechanical performance.

  17. Reorientable dipolar CuCa antisite and anomalous screening in CaCu3Ti4O12 (United States)

    Delugas, Pietro; Alippi, Paola; Fiorentini, Vincenzo; Raineri, Vito


    Based on first-principles calculations, we show that the abundant CuCa antisite defect contributes sizably to dielectric screening in single-crystal CaCu3Ti4O12 . CuCa has a multi-minimum off-center equilibrium configuration, whereby it possesses a large and easily reorientable dipole moment. The low-temperature and frequency cut-off behavior of CuCa -induced response is consistent with experiment.

  18. Polymeric Graphitic Carbon Nitride Doped with CuO Dispersed on Dealuminated Clinoptilolite (CuO/HCP): Synthesis and Characterisation


    Saheed Olalekan Sanni; Omoruyi Gold Idemudia


    CuO dispersed on dealuminated clinoptilolite (CuO/HCP) and further doped with polymeric graphitic carbon nitride (CuO/HCP-g-C3N4) was synthesized through 2 facile routes: precipitation method for CuO/HCP and impregnation through ultrasonication method for the hybrid composite material. The hybrid composite material crystalline phase, surface morphology, and structural and thermal properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-r...

  19. Effect of the components' interface on the synthesis of methanol over Cu/ZnO from CO2/H2: a microkinetic analysis based on DFT + U calculations. (United States)

    Tang, Qian-Lin; Zou, Wen-Tian; Huang, Run-Kun; Wang, Qi; Duan, Xiao-Xuan


    The elucidation of chemical reactions occurring on composite systems (e.g., copper (Cu)/zincite (ZnO)) from first principles is a challenging task because of their very large sizes and complicated equilibrium geometries. By combining the density functional theory plus U (DFT + U) method with microkinetic modeling, the present study has investigated the role of the phase boundary in CO2 hydrogenation to methanol over Cu/ZnO. The absence of hydrogenation locations created by the interface between the two catalyst components was revealed based on the calculated turnover frequency under realistic conditions, in which the importance of interfacial copper to provide spillover hydrogen for remote Cu(111) sites was stressed. Coupled with the fact that methanol production on the binary catalyst was recently believed to predominantly involve the bulk metallic surface, the spillover of interface hydrogen atoms onto Cu(111) facets facilitates the production process. The cooperative influence of the two different kinds of copper sites can be rationalized applying the Brönsted-Evans-Polanyi (BEP) relationship and allows us to find that the catalytic activity of ZnO-supported Cu catalysts is of volcano type with decrease in the particle size. Our results here may have useful implications in the future design of new Cu/ZnO-based materials for CO2 transformation to methanol.

  20. Vibrations of tetrahedral Co and Cu clusters on a Cu(111) surface

    Energy Technology Data Exchange (ETDEWEB)

    Borisova, Svetlana D.; Rusina, Galina G. [Institute of Strength Physics and Materials Science SB RAS, pr. Akademichesky 2/4, 634021 Tomsk (Russian Federation); Eremeev, Sergey V. [Institute of Strength Physics and Materials Science SB RAS, pr. Akademichesky 2/4, 634021 Tomsk (Russian Federation); Tomsk State University, pr. Lenina 36, 634050 Tomsk (Russian Federation); Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal, 4, 20018 San Sebastian/Donostia (Spain); Chulkov, Evgueni V. [Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal, 4, 20018 San Sebastian/Donostia (Spain); Depto. de Fisica de Materiales and Centro de Fisica de Materiales - CFM (CSIS-UPV/EHU), Facultad de Ciencias Quimicas, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, Apdo. 1072, 20018 San Sebastian/Donostia (Spain)


    Vibrational properties of tetrahedral clusters of Cu and Co on the Cu(111) surface are studied by using interatomic interaction potentials constructed within tight-binding second moment approximation. It was shown that interaction of the Co{sub 4} and Cu{sub 4} clusters with the substrate leads to arising of frustrated translation and frustrated rotation in-plane polarized vibrational modes localized on the cluster atoms. The vibrational modes of the free Cu{sub 4} cluster upon its adsorption on the Cu(111) surface mix with Cu bulk phonons and become almost delocalized. Contrary to that, in the Co{sub 4} cluster on the surface the high frequency modes remain strongly localized and mixed with the nearest neighbor atoms vibrations. The highest frequency vibration of the Co{sub 4} cluster splits due to different interaction with certain groups of nearest neighbor atoms (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Cu-capped surface alloys of Pt/Cu left brace 100 right brace

    CERN Document Server

    Alshamaileh, E; Wander, A


    The room-temperature deposition of 0.5 monolayer (ML) Pt on Cu left brace 100 right brace followed by annealing to 525 K results in a sharp c(2 x 2) low-energy electron diffraction (LEED) pattern. The structure of this surface alloy is investigated by means of symmetrized automated tensor low-energy electron diffraction (SATLEED) analysis and ab initio plane wave density functional calculations. The results are then compared with those for the similar system 0.5 ML Pd/Cu left brace 100 right brace. SATLEED results for the Pt/Cu left brace 100 right brace show that it consists of an ordered c(2 x 2) Cu-Pt second layer alloy capped with a pure Cu first layer. The first and second interlayer spacings are found to be expanded by +5.1 +- 1.7 and +3.5 +- 1.7% respectively (relative to the bulk Cu interlayer spacing of 1.807 A) due to the insertion of the 8% larger Pt atoms into the second layer. The ordered mixed layer is found to be rippled by 0.08 +- 0.06 A with Pt atoms rippled outwards towards the solid-vacuum ...

  2. Room Temperature Radiolytic Synthesized Cu@CuAlO2-Al2O3 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Alam Abedini


    Full Text Available Colloidal Cu@CuAlO2-Al2O3 bimetallic nanoparticles were prepared by a gamma irradiation method in an aqueous system in the presence of polyvinyl pyrrolidone (PVP and isopropanol respectively as a colloidal stabilizer and scavenger of hydrogen and hydroxyl radicals. The gamma irradiation was carried out in a 60Co gamma source chamber with different doses up to 120 kGy. The formation of Cu@CuAlO2-Al2O3 nanoparticles was observed initially by the change in color of the colloidal samples from colorless to brown. Fourier transform infrared spectroscopy (FTIR confirmed the presence of bonds between polymer chains and the metal surface at all radiation doses. Results of transmission electron microscopy (TEM, energy dispersive X-ray spectrometry (EDX, and X-ray diffraction (XRD showed that Cu@CuAlO2-Al2O3 nanoparticles are in a core-shell structure. By controlling the absorbed dose and precursor concentration, nanoclusters with different particle sizes were obtained. The average particle diameter increased with increased precursor concentration and decreased with increased dose. This is due to the competition between nucleation, growth, and aggregation processes in the formation of nanoclusters during irradiation.

  3. Diffusion of Six-Atom Cu Islands on Cu(111) and Ag(111)

    Institute of Scientific and Technical Information of China (English)

    Sardar Sikandar Hayat; I.Ahmad; M.Arshad Choudhry


    Diffusion of Cu hexamer islands on Cu(111) and Ag(111) is studied using a molecular dynamics simulation technique with many-body potentials obtained from the embedded atom method. Simulations are carried out at temperatures 300, 500 and 700 K, showing that shape-changing multiple-atom processes are more helpful for the diffusion rather than concerted motion of islands. Arrhenius plots of the diffusion coefficients provide effective energy barrier values of 161.29 ± 5 meV for Cu(111) and 179.34 ± 5 meV for Ag(111) surfaces. At 700K, one pop-up atom among island atoms is observed with correlative changes in the position and shape of the lower-layer adatoms.%@@ Diffusion of Cu hexamer islands on Cu(111) and Ag(111) is studied using a molecular dynamics simulation technique with many-body potentials obtained from the embedded atom method.Simulations are carried out at temperatures 300,500 and 700 K,showing that shape-changing multiple-atom processes are more helpful for the diffusion rather than concerted motion of islands.Arrhenius plots of the diffusion coefficients provide effective energy barrier values of 161.29 ± 5 meV for Cu(111) and 179.34 ± 5 meV for Ag(111) surfaces.At 700K,one pop-up atom among island atoms is observed with correlative changes in the position and shape of the lower-layer adatoms.

  4. Reduced Cu concentration in CuAl-LPE-grown thin Si layers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T.H.; Ciszek, T.F.; Asher, S.; Reedy, R. [National Renewable Energy Lab., Golden, CO (United States)


    Cu-Al has been found to be a good solvent system to grow macroscopically smooth Si layers with thicknesses in tens of microns on cast MG-Si substrates by liquid phase epitaxy (LPE) at temperatures near 900{degrees}C. This solvent system utilizes Al to ensure good wetting between the solution and substrate by removing silicon native oxides, and employs Cu to control Al doping into the layers. Isotropic growth is achieved because of a high concentration of solute silicon in the solution and the resulting microscopically rough interface. The incorporation of Cu in the Si layers, however, was a concern since Cu is a major solution component and is generally regarded as a bad impurity for silicon devices due to its fast diffusivity and deep energy levels in the band gap. A study by Davis shows that Cu will nonetheless not degrade solar cell performance until above a level of 10{sup 17} cm{sup -3}. This threshold is expected to be even higher for thin layer silicon solar cells owing to the less stringent requirement on minority carrier diffusion length. But to ensure long term stability of solar cells, lower Cu concentrations in the thin layers are still preferred.

  5. Luminescent CuInS2 quantum dots by partial cation exchange in Cu2- xS nanocrystals

    NARCIS (Netherlands)

    Van Der Stam, Ward; Berends, Anne C.; Rabouw, Freddy T.; Willhammar, Tom; Ke, Xiaoxing; Meeldijk, Johannes D.; Bals, Sara; De Mello Donega, Celso


    Here, we show successful partial cation exchange reactions in Cu2-xS nanocrystals (NCs) yielding luminescent CuInS2 (CIS) NCs. Our approach of mild reaction conditions ensures slow Cu extraction rates, which results in a balance with the slow In incorporation rate. With this method, we obtain CIS NC

  6. Enhancement in visible light photocatalytic activity by embedding Cu nanoparticles over CuS/MCM-41 nanocomposite (United States)

    Sohrabnezhad, Sh.; Karamzadeh, M.


    This article indicate the biogenic synthesis of copper nanoparticles (Cu NPs) using the borage flowers extract of Borago officinalis over CuS/MCM-41 nanocomposite (NC). No external reducing was utilized in the developed method. The CuS-MCM-41 NC was used as stabilizing agent. The synthesis of CuS nanostructure in MCM-41 material has been realized by hydrothermal method. Their physiochemical properties have been characterized by X-ray diffraction, transmission electron microscopy (TEM), UV-Visible diffuse reflectance spectroscopy, and Fourier transform infrared spectroscopy. On the basis of TEM images, a layer of Cu NPs has been located over CuS/MCM-41 NC with average diameter of 60-80 nm. The results revealed the spherical nature of the prepared Cu NPs with diameter less than 10 nm. The DR spectra of Cu NPs in MCM-41 and CuS-MCM-41 NCs showed surface plasmon resonance bands at 570 and 500-600 nm, respectively. The photocatalytic activity was evaluated under visible light irradiation using the photocatalytic degradation of methylene blue (MB) as a model reaction. The prepared Cu/CuS/MCM-41 nanocomposite microspheres showed higher photodegradation ability for MB than CuS/MCM-41. The degradation of MB achieved up to 80% after 60 min and the nanocomposite could be recycled and reused.

  7. In-situ STM study of phosphate adsorption on Cu(111), Au(111) and Cu/Au(111) electrodes

    DEFF Research Database (Denmark)

    Schlaup, Christian; Horch, Sebastian


    The interaction of Cu(111), Au(111) and Cu-covered Au(111) electrodes with a neutral phosphate buffer solution has been studied by means of cyclic voltammetry (CV) and in situ electrochemical scanning tunneling microscopy (EC-STM). Under low potential conditions, both the Cu(111) and the Au(111...

  8. Characterization of task-free and task-performance brain states via functional connectome patterns. (United States)

    Zhang, Xin; Guo, Lei; Li, Xiang; Zhang, Tuo; Zhu, Dajiang; Li, Kaiming; Chen, Hanbo; Lv, Jinglei; Jin, Changfeng; Zhao, Qun; Li, Lingjiang; Liu, Tianming


    Both resting state fMRI (R-fMRI) and task-based fMRI (T-fMRI) have been widely used to study the functional activities of the human brain during task-free and task-performance periods, respectively. However, due to the difficulty in strictly controlling the participating subject's mental status and their cognitive behaviors during R-fMRI/T-fMRI scans, it has been challenging to ascertain whether or not an R-fMRI/T-fMRI scan truly reflects the participant's functional brain states during task-free/task-performance periods. This paper presents a novel computational approach to characterizing and differentiating the brain's functional status into task-free or task-performance states, by which the functional brain activities can be effectively understood and differentiated. Briefly, the brain's functional state is represented by a whole-brain quasi-stable connectome pattern (WQCP) of R-fMRI or T-fMRI data based on 358 consistent cortical landmarks across individuals, and then an effective sparse representation method was applied to learn the atomic connectome patterns (ACPs) of both task-free and task-performance states. Experimental results demonstrated that the learned ACPs for R-fMRI and T-fMRI datasets are substantially different, as expected. A certain portion of ACPs from R-fMRI and T-fMRI data were overlapped, suggesting some subjects with overlapping ACPs were not in the expected task-free/task-performance brain states. Besides, potential outliers in the T-fMRI dataset were further investigated via functional activation detections in different groups, and our results revealed unexpected task-performances of some subjects. This work offers novel insights into the functional architectures of the brain.

  9. Exploring the Cosmic Frontier, Task A - Direct Detection of Dark Matter, Task B - Experimental Particle Astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, John A.J. [Univ. of New Mexico, Albuquerque, NM (United States); Gold, Michael S. [Univ. of New Mexico, Albuquerque, NM (United States)


    This report summarizes the work of Task A and B for the period 2013-2016. For Task A the work is for direct detection of dark matter with the single-phase liquid argon experiment Mini-CLEAN. For Task B the work is for the search for new physics in the analysis of fluorescence events with the Auger experiment and for the search for the indirect detection of dark matter with the HAWC experiment.

  10. Anterior medial prefrontal cortex exhibits activation during task preparation but deactivation during task execution.

    Directory of Open Access Journals (Sweden)

    Hideya Koshino

    Full Text Available BACKGROUND: The anterior prefrontal cortex (PFC exhibits activation during some cognitive tasks, including episodic memory, reasoning, attention, multitasking, task sets, decision making, mentalizing, and processing of self-referenced information. However, the medial part of anterior PFC is part of the default mode network (DMN, which shows deactivation during various goal-directed cognitive tasks compared to a resting baseline. One possible factor for this pattern is that activity in the anterior medial PFC (MPFC is affected by dynamic allocation of attentional resources depending on task demands. We investigated this possibility using an event related fMRI with a face working memory task. METHODOLOGY/PRINCIPAL FINDINGS: Sixteen students participated in a single fMRI session. They were asked to form a task set to remember the faces (Face memory condition or to ignore them (No face memory condition, then they were given 6 seconds of preparation period before the onset of the face stimuli. During this 6-second period, four single digits were presented one at a time at the center of the display, and participants were asked to add them and to remember the final answer. When participants formed a task set to remember faces, the anterior MPFC exhibited activation during a task preparation period but deactivation during a task execution period within a single trial. CONCLUSIONS/SIGNIFICANCE: The results suggest that the anterior MPFC plays a role in task set formation but is not involved in execution of the face working memory task. Therefore, when attentional resources are allocated to other brain regions during task execution, the anterior MPFC shows deactivation. The results suggest that activation and deactivation in the anterior MPFC are affected by dynamic allocation of processing resources across different phases of processing.

  11. Dual task performance in normal aging: a comparison of choice reaction time tasks.

    Directory of Open Access Journals (Sweden)

    Eleftheria Vaportzis

    Full Text Available This study examined dual task performance in 28 younger (18-30 years and 28 older (>60 years adults using two sets of choice reaction time (RT tasks paired with digit tasks. Set one paired simple choice RT with digit forward; set two paired complex choice RT with digit backward. Each task within each set had easy and hard conditions. For the simple choice RT, participants viewed single letters and pressed a specified keyboard key if the letter was X or Z or a different key for other letters (easy. For the hard condition, there were 4 target letters (X, Z, O, Y. Digit forward consisted of 4 (easy or 5 (hard digits. For the complex choice RT, participants viewed 4×4 matrices of Xs and Os, and indicated whether four Xs (easy or four Xs or four Os (hard appeared in a row. Digit backward consisted of 3 (easy or 4 (hard digits. Within each set, participants performed every possible combination of tasks. We found that in the simple choice RT tasks older adults were significantly slower than, but as accurate as younger adults. In the complex choice RT tasks, older adults were significantly less accurate, but as fast as younger adults. For both age groups and both dual task sets, RT decreased and error rates increased with greater task difficulty. Older adults had greater dual task costs for error rates in the simple choice RT, whereas in the complex choice RT, it was the younger group that had greater dual task costs. Findings suggest that younger and older adults may adopt differential behavioral strategies depending on complexity and difficulty of dual tasks.

  12. 75 FR 45606 - Interagency Ocean Policy Task Force-Final Recommendations of the Interagency Ocean Policy Task Force (United States)


    ... QUALITY Interagency Ocean Policy Task Force--Final Recommendations of the Interagency Ocean Policy Task... Task Force's ] ``Final Recommendations of the Interagency Ocean Policy Task Force''. SUMMARY: On June 12, 2009, the President established an Interagency Ocean Policy Task Force, led by the Chair of...

  13. Attentional switches and dual-task interference.

    Directory of Open Access Journals (Sweden)

    Janne F Ettwig

    Full Text Available In four experiments, we studied the time course of interference between detection of an oddball orientation target (OT in an 8-item circular search display, and identification of a letter target (LT in a central stream of distractor letters. Dual-task performance for different temporal lags between targets was compared to single-task performance. When the LT preceded the OT, dual-task performance levels were reduced at short inter-target intervals of 0 and 166 ms; when the OT preceded the LT, the dual-task interference was unexpectedly stronger and lasted for up to 500 ms. Resource competition due to temporally overlapping target processing cannot account for this result, because the feature search task is easier than the letter identification task, and therefore would have generated less interference when presented first. Two alternative explanations were explored. First, by manipulating the spatial inter-target distance, we investigated to what degree there is a penalty associated with directing the attentional window from a large object (the search display to a smaller object (the central letter stream. Second, by varying the duration of the OT and subsequent mask, we studied whether the interference was caused by the difficulty of disengaging attention from the search display. Results support this second explanation and thus indicate that switching attention to the letter stream is hampered by the continuing presence of (masked search display items. This result shows that attentional effects may play a major role in dual-task execution and can easily obscure interference due to other factors such as resource competition.

  14. Task representation in individual and joint settings

    Directory of Open Access Journals (Sweden)

    Wolfgang ePrinz


    Full Text Available This paper outlines a framework for task representation and discusses applications to interference tasks in individual and joint settings. The framework is derived from the Theory of Event Coding. This theory regards task sets as transient assemblies of event codes in which stimulus and response codes interact and shape each other in particular ways. On the one hand, stimulus and response codes compete with each other within their respective subsets (horizontal interactions. On the other hand, stimulus and response code cooperate with each other (vertical interactions. Code interactions instantiating competition and cooperation apply to two time scales: on-line performance (i.e., doing the task and off-line implementation (i.e., setting the task. Interference arises when stimulus and response codes overlap in features that are irrelevant for stimulus identification, but relevant for response selection. To resolve this dilemma, the feature profiles of event codes may become restructured in various ways. The framework is applied to three kinds of interference paradigms. Special emphasis is given to joint settings where tasks are shared between two participants. Major conclusions derived from these applications include: (1 Response competition is the chief driver of interference. Likewise, different modes of response competition give rise to different patterns of interference. (2 The type of features in which stimulus and response codes overlap is also a crucial factor. Different types of such features give likewise rise to different patterns of interference. (3 Task sets for joint settings conflate intraindividual conflicts between responses (what, with interindividual conflicts between responding agents (whom. Features of response codes may, therefore, not only address responses, but also responding agents (both physically and socially.

  15. Motor hysteresis in a sequential grasping and pointing task is absent in task-critical joints. (United States)

    Schütz, Christoph; Weigelt, Matthias; Schack, Thomas


    In a prior study (Schütz et al. in Exp Brain Res 2016. doi: 10.1007/s00221-016-4608-6 ), we demonstrated that the cognitive cost of motor planning did not differ in a vertical pointing and grasping task. It was unclear whether the similar cost implied that both tasks required the same number of independent degrees of freedom (IDOFs) or that the number of IDOFs did not affect motor planning. To differentiate between both cases, a reanalysis of the prior data was conducted. The number of IDOFs in the pointing and grasping tasks was computed by factor analysis. In both tasks, two IDOFs were used, which was the minimum number required for position control. This indicates that hand alignment in the grasping task did not require an additional IDOF. No conclusions regarding the link between the cognitive cost of motor planning and the number of IDOFs could be drawn. A subset of task-critical joint angles was not affected by motor hysteresis. This indicates that a joint's susceptibility to motor hysteresis depends on its relevance to the task goal. In task-critical joints, planning cost minimization by motor plan reuse is suppressed in favor of the task goal.

  16. Evolution of microstructure in centrifugal cast Al-Cu alloy

    Directory of Open Access Journals (Sweden)

    Sui Yanwei


    Full Text Available In this research, the effects of centrifugal radius and mould rotation speed on microstructure in centrifugal-cast Al-Cu alloy have been investigated. The results show that, with increase of the centrifugal radius or mould rotation speed, the grain size of centrifugal-cast Al-Cu alloy decreases gradually, while the content of white phases containing the Al2Cu precipitated from α-phase, divorced eutectic and regular eutectic microstructure increases, leading to higher Cu macrosegregation. The variation level of microstructure in centrifugal-cast Al-Cu alloy at 600 rpm of mould rotation speed is greater than that at 300 rpm.

  17. Rare-earth magnetism in cuprates with T' structure. [GdPrCuO; GdNdCuO; GdSmCuO; GdEuCuO

    Energy Technology Data Exchange (ETDEWEB)

    Czjzek, G. (Kernforschungszentrum Karlsruhe, INFP and ITP (Germany)); Roth, G. (Kernforschungszentrum Karlsruhe, INFP and ITP (Germany)); Kroener, T. (Kernforschungszentrum Karlsruhe, INFP and ITP (Germany)); Adelmann, P. (Kernforschungszentrum Karlsruhe, INFP and ITP (Germany))


    Cuprates of composition (Gd[sub 1-x]R[sub x])[sub 2]CuO[sub 4], R = Pr, Nd, Sm, Eu, have been studied by complementary experimental techniques. Only in compounds with Sm, exchange interactions between Sm and Cu moments are ineffective since the easy axis of the Sm moments is perpendicular to the Cu - O planes to which the Cu moments are confined. Here, we present new evidence that in the other cuprates with magnetic rare earths, R - Cu exchange interactions strongly influence the magnetic properties. (orig.)

  18. Electroless deposition of Cu on multiwalled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    YUAN Dingsheng; LIU Yingliang


    Copper has been deposited on the surface of multiwalled carbon nanotubes (MWNTs) and inside MWNTs by electroless deposition. The as-prepared Cu-MWNT composite materials have been characterized by X-ray diffractometer(XRD), transmission electron microscopy (TEM), and electrochemical measurement. XRD analyses showed that Cu was a face-centered cubic (fcc) structure. The average size of Cu was calculated by Scherrer's formula from XRD data, and it was11 nm. TEM revealed that Cu grains on the surface of MWNTs were uniform with the sizes of about 30-60 nm. The electrochemical measurement indicated that Cu-MWNT composite materials possessed fine electron conductivity.

  19. Effects of Cu2+ on characteristic of SV currents

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Liping; YANG; Pin


    Applying the patch-clamp technique to vacuoles from Radish we studied the effects of Cu2+ on Slow Vacuolar (SV) current's characteristic. Our results show that Cu2+ in bath solution at higher concentration inhibits SV currents and the percentage of inhibition increases with increasing concentration and changes with different voltage. When at lower concentration, Cu2+ significantly promotes the SV currents and the promotion ratio decrease with increasing voltage. At the same time, the time constants of activation become lesser after adding Cu2+. These results show that there may be some Cu2+ binding sites on SV channels and binding to which can change SV current's characteristic.

  20. Studying Cu Alloy Corrosion Products in Cooling Liquid

    Institute of Scientific and Technical Information of China (English)


    The effect of cooiing liquid used for heat exchangers on the Cu alloy corrosion products has been examined using potential-time measurements under applied current condition (anodizing), potentiodynamic polarization, X-ray diffraction (XRD) and infrared spectroscopy (IR). The corrosion products formed on the Cu alloy surface during anodizing, are Cu2O, Cu2(OH)3CI, and Cu2S. NaCI is detected in the corrosion products. The film formation depends on the applied current and the shift of potential to nobler direction indicates its formation progress.