Repetition Condition Research Articles

The Effect of Spaced Repetition on Learning and Knowledge Transfer in a Large Cohort of Practicing Physicians.

Spaced repetition is superior to repeated study for learning and knowledge retention, but literature on the effect of different spaced repetition strategies is lacking. The authors evaluated the effects of different spaced repetition strategies on long-term knowledge retention and transfer. This prospective cohort study, conducted from October 1, 2020, through July 20, 2023, used the American Board of Family Medicine Continuous Knowledge Self-Assessment (CKSA) to assess learning and knowledge transfer of diplomates and residents. Participants were randomized to a control group or 1 of 5 spaced repetition conditions during 5 calendar quarters (January 1, 2021, to March 31, 2022). Participants in the spaced repetition groups received 6 repeated questions once or twice. Incorrectly but confidently answered questions were prioritized for repetition, with decreasing priority for questions answered incorrectly with lesser confidence. All participants received 6 rewritten questions corresponding to their initial questions chosen for repetition in quarter 10 (second quarter of calendar year 2023). A total of 26,258 family physicians or residents who completed the CKSA in the baseline period were randomized. Spaced repetition was superior to no spaced repetition for learning at quarter 6 (58.03% vs 43.20%, P < .001, Cohen d = 0.62) and knowledge transfer at quarter 10 (58.33% vs 52.39%, P < .001, Cohen d = 0.26). Double-spaced repetitions were superior to single-spaced repetitions for learning (62.24% vs 51.83%, P < .001, Cohen d = 0.43) and transfer (60.08% vs 55.72%, P < .001, Cohen d = 0.20). There were no meaningful differences in learning or transfer between repetition strategy chosen in the single- or double-repetition groups. This study affirms the value of spaced repetition in improving learning and retention in medical education and ongoing professional development.

The temporal dynamics of familiar face recognition: Event-related brain potentials reveal the efficient activation of facial identity representations

While it is widely known that humans are typically highly accurate at recognizing familiar faces, it is less clear how efficiently recognition is achieved. In a series of three experiments, we used event-related brain potentials (ERP) in a repetition priming paradigm to examine the efficiency of familiar face recognition. Specifically, we varied the presentation time of the prime stimulus between 500 ms and 33 ms (Experiments 1 and 2), and additionally used backward masks (Experiment 3) to prevent the potential occurrence of visual aftereffects. Crucially, to test for the recognition of facial identity rather than a specific picture, we used different images of the same facial identities in repetition conditions. We observed clear ERP repetition priming effects between 300 and 500 ms after target onset at all prime durations, which suggests that the prime stimulus was sufficiently well processed to allow for facilitated recognition of the target in all conditions. This finding held true even in severely restricted viewing conditions including very brief prime durations and backward masks. We conclude that the facial recognition system is both highly effective and efficient, thus allowing for our impressive ability to recognise the faces that we know.

The effects of task repetition and corrective feedback on L2 writing development

ABSTRACT This study examines the joint effects of task repetition and corrective feedback on EFL learners’ writing accuracy. Two types of task repetition were investigated: identical repetition where learners repeated the same task, and procedural repetition where learners performed tasks with different content following the same procedure. Under each repetition condition, learners received direct correction or metalinguistic feedback on their erroneous use of three linguistic structures: the past tense, articles, and prepositions. 80 Korean university EFL learners were randomly assigned to four groups: identical repetition + direct feedback, identical repetition + metalinguistic feedback, procedural repetition + direct feedback, and procedural repetition + metalinguistic feedback, and received one of the four instructional treatments. The results showed that (1) procedural repetition was superior to identical repetition in enhancing learners’ writing accuracy regardless of whether direct feedback or metalinguistic feedback was provided, and (2) there were no significant differences between the two types of feedback despite a trend toward a greater effect for metalinguistic feedback for the past tense and a greater effect for direct correction for articles and prepositions. The results demonstrate the advantage of procedural repetition over identical repetition in enhancing the effects of corrective feedback in L2 writing.

Lower nonword syllable sequence repetition accuracy in adults who stutter is related to differences in audio-motor oscillations

ObjectiveThe goal of this study was to use independent component analysis (ICA) of high-density electroencephalography (EEG) to investigate whether differences in audio-motor neural oscillations are related to nonword syllable repetition accuracy in a group of adults who stutter compared to typically fluent speakers. MethodsEEG was recorded using 128 channels from 23 typically fluent speakers and 23 adults who stutter matched for age, sex, and handedness. EEG was recorded during delayed, 2 and 4 bilabial nonword syllable repetition conditions. Scalp-topography, dipole source estimates, and power spectral density (PSD) were computed for each independent component (IC) and used to cluster similar ICs across participants. Event-related spectral perturbations (ERSPs) were computed for each IC cluster to examine changes over time in the repetition conditions and to examine how dynamic changes in ERSPs are related to syllable repetition accuracy. ResultsFindings indicated significantly lower accuracy on a measure of percentage correct trials in the AWS group and for a normalized measure of syllable load performance across conditions. Analysis of ERSPs revealed significantly lower alpha/beta ERD in left and right μ ICs and in left and right posterior temporal lobe α ICs in AWS compared to TFS (CC p < 0.05). Pearson correlations with %CT for frequency across time showed strong relationships with accuracy (FWE<0.05) during maintenance in the TFS group and during execution in the AWS group. ConclusionsFindings implicate lower alpha/beta ERD (8–30 Hz) during syllable encoding over posterior temporal ICs and execution in left temporal/sensorimotor components. Strong correlations with accuracy and interindividual differences in ∼6–8 Hz ERSPs during execution implicate differences in motor and auditory-sensory monitoring during syllable sequence execution in AWS.

Lexical encoding of second language tones in English learners of Mandarin

The study investigates how native and non-native differences in tone perception influence lexical encoding of second language (L2) tones. Previous work shows that tone language listeners perceived tones as phonemic categories while non-tone language listeners relied more on psychoacoustic cues such as pitch height to discriminate stimulus tones. However, little is known about the influence of such differences in perception on L2 tonal encoding. In the present study, two experiments were conducted with nineteen English learners of Mandarin and 20 Mandarin native speakers. Experiment 1 was an ABX task. Results showed that while native speakers’ overall performance was superior to L2 listeners’, both groups poorly discriminated tone pairs with shared tone contours (i.e., T2-T3). Experiment 2 was a medium-lag repetition priming task. In the repetition condition, significant facilitations were observed in both language groups. In the minimal-tone-pair condition, despite T2-T3 contrasts posing greater challenge for both groups to accurately distinguish than other tonal contrasts as shown in Experiment 1, positive priming was observed only in the L2 group. The findings from the two experiments suggest that the L2 listeners, although quite proficient in Mandarin, have yet to achieve native-like competence in regard to lexical tones.

Repetition costs in task switching are not equal to cue switching costs: evidence from a cue-independent context

Recent task-switching studies highlighted the presence of feature binding processes. These studies documented that even a task-irrelevant feature (the context, henceforth) may be bound with the task and the response in each trial. When the context repeated in the following trial, it supposedly retrieved the bound features, causing benefits when the task and the response repeated and costs otherwise (i.e. full repetition benefits). In the present study, we aim to rule out an alternative explanation for such full repetition benefits in task switching. These benefits were observed in studies that used a cue-related context so that full repetition conditions always implied a cue repetition. Therefore, these full repetition benefits may be ascribed to the priming of cue encoding, instead of the binding of the context. In the present study, we implemented a similar context manipulation but used univalent target stimuli and did not present any cue. Hence, the varying context was never cue-related. We still found full repetition benefits but only when the context appeared before the target and not when they appeared simultaneously. Thus, full repetition benefits can be observed in the absence of priming of cue encoding. However, the context must occupy a prominent position (i.e. at the beginning of the trial). These results, therefore, reinforce the hypothesis that full repetition benefits stem from binding processes that take place on a trial-by-trial basis and involve both task-relevant (the task and the response) and task-irrelevant features (the context).

Contrastive stress in persons with Parkinson's disease who speak Mandarin: Task effect in production and preserved perception

BackgroundSpeech in persons with Parkinson's disease (PD) is characterized by impaired prosody (e.g., monotone, abnormal rate, reduced loudness). Most studies on prosodic abnormalities in PD have been obtained from individuals who speak non-tone languages, where prosodic contrasts do not systematically contribute to lexical meanings. In a tone language such as Mandarin, pitch not only carries affective information but also serves to distinguish lexical meanings. It is not known how well persons with PD, who speak a tone language, convey contrastive stress (specific intonational cues signaling topic and theme) for discourse purposes in production, or how well they perceive these contrasts. MethodExperiment 1 investigated production of contrastive stress by persons with PD who speak Mandarin using two different speech tasks, Elicitation and Repetition. PD participants and healthy controls (HC) produced short sentences with focus in different positions during the two task conditions. As an indirect measurement of the quality of the participants’ production of contrastive stress, healthy listeners served as raters to identify focus positions in the sentences and provide goodness ratings to each produced contrastive stress. Experiment 2 examined perceptual ability, measuring PD participants' identification through listening of contrastive stress on utterances produced by a healthy speaker. ResultsFor the Production Study (Experiment 1), the results revealed significantly poorer performance in the PD than the HC group in Elicitation and Repetition. Consistent with previous studies, a task effect was found; study participants demonstrated better performance in Repetition than in Elicitation. Results for the examination of perceptual ability in Experiment 2 revealed that PD and HC participants were equally successful in perceiving contrastive stress in Mandarin utterances produced by a healthy speaker. DiscussionThis study extended previous literature by measuring production and perception of contrastive stress in persons with PD who speak a tone language. Contrastive stress was detected with decreased accuracy in speech produced by persons with PD compared to healthy controls. However, performance was relatively preserved in a repetition condition compared to an elicitation condition. In contrast to the production results, speakers with PD were as successful as HC in perceiving sentential focus, consistent with previous research reporting a discrepancy between production and perception in persons with PD.

Truth by repetition … Without repetition: Testing the effect of instructed repetition on truth judgments.

Past research indicates that people judge repeated statements as more true than new ones. An experiential consequence of repetition that may underly this "truth effect" is processing fluency: Processing statements feels easier following their repetition. In three preregistered experiments (N = 684), we examined the effect of merely instructed repetition (i.e., not experienced) on truth judgments. Experiments 1-2 instructed participants that some statements were present (vs. absent) in an exposure phase allegedly undergone by other individuals. We then asked them to rate such statements based on how they thought those individuals would have done. Overall, participants rated repeated statements as more true than new statements. The instruction-based repetition effects were significant but also significantly weaker than those elicited by the experience of repetition (Experiments 1 and 2). Additionally, Experiment 2 clarified that adding a repetition status tag in the experienced repetition condition did not impact truth judgments. Experiment 3 further showed that the instruction-based effect was still detectable when participants provided truth judgments for themselves rather than estimating other people's judgments. We discuss the mechanisms that can explain these effects and their implications for advancing our understanding of the truth effect. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

False Memory Facilitation Through Semantic Overlap.

This study investigated the effects of semantic overlap from multiple sources on false memories. Participants were presented with paired study lists comprising items highly associated with one nonstudied critical item. There were three types of list pairs: (1) the sharing condition, in which the words in both lists were classified into different semantic groups that converged on the same critical word (semantic overlap), (2) the repetition condition, in which the two lists comprised identical words, and (3) the single condition, in which the paired lists were attributed to different semantic groups that did not share a critical item. In Experiment 1, participants were presented with the paired study lists and responded to free recall tests and a recognition test including remember-know judgments. In Experiment 2, the participants responded to a recognition test, and the participants in Experiment 3 recalled the studied items. The results indicated that the false recall and false recognition rates in the sharing condition were higher than those in the repetition and single conditions. These results suggest that activation from multiple independent sources may have an accumulative additive effect. The findings are discussed in relation to the Activation-Monitoring theory.

Morphological Effects on Orthographic Learning in Monolingual English-Speaking and Bilingual Chinese-English-Speaking Children

ABSTRACT Morphological knowledge is known to be positively associated with reading ability. However, whether morphological knowledge affects children’s learning of new orthographic representations is less clear. Purpose This study aimed to investigate morphological effects on orthographic learning in English, and whether this effect, if any, is different for monolingual compared to Chinese-English-speaking bilingual children, who often have difficulty acquiring English inflectional morphology. Method 59 Year 2 children, including 29 English-speaking monolinguals and 30 Chinese-English-speaking bilinguals participated. We assessed children’s preexisting English inflectional morphological knowledge. The children learned twelve novel words that were either presented with morphological variation (e.g., vack, vacks, vacking, vacked) or pure repetition (e.g., vack x 4). Orthographic learning was measured by orthographic choice and spelling tasks. Results 1) orthographic learning from the spelling task showed better performance in the repetition condition, 2) there were no differences in orthographic learning between the monolinguals and bilinguals, despite the fact that the monolinguals had better inflectional morphological knowledge than the bilinguals. Conclusion Children learned novel written words better when they are presented without morphological variation, supporting the item-based feature of the self-teaching hypothesis. Chinese-English-speaking bilinguals’ weaker English morphological knowledge does not seem to hinder their orthographic learning ability.

Reconfiguration of response-set in task switching: Event-related potential evidence.

In task switching, an interaction between task and response is often observed, with response repetition (RR) benefits in task-repeat trials and RR costs in task-switch trials. The theoretical accounts of the RR effect remain controversial, and neuroscience evidence is scarce. The present study utilized the event-related potentials (ERPs) method to explore the neural mechanism underlying the RR effect by adopting a cued task-switching paradigm. The ERP results revealed the interaction between task and response in the P3b time window, with a response switch positivity under task-repetition conditions and an RR positivity under task-switching conditions. In addition, there were RR positivity in the N2 irrespective of task transition and in the late component (LC, 550-600 ms) that only under the task repetition condition. On the individual level, the RR benefit positively correlated with the RR positivity in the LC, while the RR costs negatively correlated with RR positivity in the N2/P3 component. These results suggest that both response reconfiguration and episodic-retrieval make contributions to the RR effects, which were also discussed in terms of predictive model for a domain-general inference and learning of perceptual categories.

Factors Affecting Pronunciation Accuracy in English as a Foreign Language: The Case of Spanish-Catalan Intermediate Learners

In the present study, we investigate the factors that influence pronunciation accuracy by Spanish-Catalan bilinguals learning English as a foreign language (EFL). A group of intermediate EFL learners were recorded producing a series of cognate and non-cognate words in two different conditions: a reading aloud task and a delayed repetition task. In the reading aloud task, the target words were presented as visual prompts in a carrier phrase. In the delayed repetition, words were presented aurally and participants repeated them after a two-second delay followed by an audio prompt. The words were phonemically transcribed using PHON. As expected, task condition and cognate-status influenced the percentage of correct vowels and consonants. The number of errors was significantly higher in the reading aloud condition than in the delayed repetition condition. Cognates exhibited more pronunciation errors than non-cognates. In contrast, learners’ vocabulary-size and lexical frequency did not have a clear impact on the results. These findings suggest that focusing on spelling might interfere with the way EFL learners process the phonological forms of words.

Spaced Repetition in a Cohort of Practicing Physicians: Methods and Preliminary Results.

Purpose: Spaced repeated testing over time results in better long-term knowledge retention than repeated study of the same material. It is particularly effective when feedback is provided, initial repetitions occur early, and answering questions requires application of knowledge through use of short-answer or context-rich multiple-choice questions. 1–4 American Board of Medical Specialties boards incorporate longitudinal knowledge assessments in their continuing certification programs, 5 but most have not yet systematically incorporated spaced repetition. The goal of this study is to compare the effect of 5 different spaced repetition strategies on American Board of Family Medicine (ABFM) Diplomate knowledge retention and transfer of knowledge from one clinical scenario to another. We report the study methods and will report preliminary results from this ongoing work. Approach: Physicians participating in the ABFM Continuing Knowledge Self-Assessment (CKSA) receive 25 questions per quarter. After answering each question, they rate their confidence in their answer on a 6-point scale before receiving feedback, an educational critique, and list of appropriate references. Twenty-six thousand two hundred fifty-five family physicians who completed the CKSA in the fourth quarter of 2020 (baseline period) were eligible for study inclusion. Participants were randomized to a control group or 1 of 5 spaced repetition conditions over the subsequent 5 calendar quarters (January 1, 2021, to March 31, 2022). Control group participants received no repeated questions during this time period. Participants in the other 5 groups received 6 questions repeated either once or twice; the interval between repetitions differed between each group. Incorrectly answered baseline questions were prioritized for spaced repetition—those answered extremely confidently received highest priority, with decreasing priority for those questions answered with lesser degrees of confidence. If necessary, correctly answered questions could then be selected for spaced repetition, with higher priority for questions not answered confidently (e.g., “guesses”) than those answered more confidently. Physicians remain in the study unless opting out or failing to complete all 25 CKSA questions in a quarter in which they were scheduled to receive repeated questions. In quarter 6 of the study, all remaining participants will receive their 6 repeated questions. The primary analysis will compare differences in enduring learning (the percentage of incorrectly answered baseline questions subsequently answered correctly during quarter 6) between physicians receiving any spaced repetition questions in quarters 1–5 compared with the control group, who will have gone 18 months without seeing repeated questions. Subgroup analyses will compare differences in learning between physicians receiving one repetition compared with those receiving 2, differences in learning between the 2 single-spaced repletion strategies, and differences in learning between the 3 double-spaced repetition strategies. Cloned questions emphasize the same learning points as the original (base) question and are designed to measure the transfer of knowledge from one clinical situation to another. In quarter 8 of the study, physicians in all groups will receive questions cloned from their selected baseline questions. We will then examine the effects of different numbers and intervals of spaced repetition on transfer of knowledge from one clinical scenario to another. Outcomes: We will present data on participant retention rates through the first 6 study quarters, and preliminary analysis of learning in the different groups. Significance: To date, spaced repetition has not been systematically evaluated in large cohorts of practicing physicians. This study can inform the development and utilization of spaced repetition strategies by health professions educators across the continuum. The results of this study will help ABFM determine a strategy for and the potential added value of spaced repetition in the lifelong learning and self-assessment component of continuous certification. Acknowledgments: The authors wish to thank Zachary Morgan, Emily Banik, Matt Wilhoite, and Prasad Chodavarapu for their assistance with data acquisition and analysis.

Tension experience induced by tonal and melodic shift at music phrase boundaries

Music tension is a link between music structures and emotions. As music unfolds, developmental patterns induce various emotional experiences, but the relationship between developmental patterns and tension experience remains unclear. The present study compared two developmental patterns of two successive phrases (tonal shift and melodic shift) with repetition condition to investigate the relationship with tension experience. Professional musicians rated on-line felt tension and EEG responses were recorded while listening to music sequences. Behavioral results showed that tension ratings under tonal and melodic shift conditions were higher than those under repetition conditions. ERP results showed larger potentials at early P300 and late positive component (LPC) time windows under tonal shift condition, and early right anterior negativity (ERAN) and LPC under melodic shift condition. ERSP results showed early beta and late gamma power increased under tonal shift condition, theta power decreased and alpha power increased under melodic shift condition. Our findings suggest that developmental patterns play a vital role in tension experiences; tonal shift affects tension by tonal shift detection and integration, while melodic shift affects tension by attentional processing and working memory integration. From the perspective of Event Structure Processing Model, solid evidence was given to specify the time-span segmentation and reduction.

Illuminating the prefrontal neural correlates of action sequence disassembling in response–response binding

Execution of two independent actions in quick succession results in transient binding of these two actions. Subsequent repetition of any of these actions automatically retrieves the other. This process is probably fundamental for developing complex action sequences. However, rigid bindings between two actions are not always adaptive. Sometimes, it is necessary to repeat only one of the two previously executed actions. In such situations, stored action sequences must be disassembled, for the sake of flexibility. Exact mechanisms that allow for such an active unbinding of actions remain largely unknown, but it stands to reason, that some form of prefrontal executive control is necessary. Building on prior neuronal research that explored other forms of binding (e.g. between distractors and responses and abstract representations and responses), we explored middle and superior frontal correlates of -response binding in a sequential classification task with functional near-infrared spectroscopy. We found that anterior dorsolateral prefrontal cortex activity varied as a function of response–repetition condition. Activity in the right anterior dorsolateral prefrontal cortex correlated with changes in reaction times due to response–response binding. Our results indicate that the right anterior dorsolateral prefrontal cortex dismantles bindings between consecutive actions, whenever such bindings interfere with current action goals.

Non-phase-locked alpha oscillations are involved in spontaneous racial categorization of faces

Racial categorization of faces has a notable impact on human behavior, but its neural underpinnings remain unresolved. Previous electroencephalography (EEG) research focused on contributions of phase-locked neural activities to racial categorization of faces. We investigated functional roles of non-phase-locked neural oscillations in spontaneous racial categorization of faces by recording EEG from Chinese adults who performed an individuation task on Asian/White faces in Experiment 1 and on Asian/Black faces in Experiment 2. We quantified neural processes involved in spontaneous racial categorization of faces by examining repetition suppression of non-phase-locked neural oscillations when participants viewed faces of one race presented repeatedly in the same block of trials (repetition condition), or faces of two races presented alternately in the same block of trials (alternating condition). We found decreased power of alpha (9–13 Hz) oscillations in the repetition than alternating conditions at 80–240 ms over frontal-central electrodes induced by White/Black (but not Asian) faces. Moreover, larger repetition suppression of alpha oscillations in response to White/Black (vs. Asian) faces predicted greater implicit negative attitudes toward White/Black faces across individuals. Our findings suggest that non-phase-locked alpha oscillations are engaged in spontaneous racial categorization of faces and are associated with implicit negative attitudes toward other-race faces.

Individual differences in memory predict changes in breakdown and repair fluency but not speed fluency: A short-term fluency training intervention study

AbstractThe purpose of this intervention study is to reveal the extent to which memory-related aptitudes are implicated in the second language (L2) fluency development fostered by task repetition. English L2 learners are engaged in oral narrative tasks three times per day under two different 3-day task repetition schedules: blocked (Day 1: A-A-A, Day 2: B-B-B, Day 3: C-C-C) versus interleaved (Day 1: A-B-C, Day 2: A-B-C, Day 3: A-B-C). Their phonological short-term memory (PSTM), attention control, and associative memory were used as predictors of fluency changes measured through speed, breakdown, and repair fluency behaviors. Results showed that while the articulation rate change was not explained by any of the examined predictors, breakdown and repair fluency were predicted by different memory components. Specifically, PSTM was associated with mid-clause pause decrease during the training phase, while associative memory was linked to the increase in clause-final pauses in the posttest. Attention control, as well as PSTM, was related to greater repair frequency in the posttest, indicating increased learners’ attention to speech monitoring. Furthermore, PSTM and associative memory contributed to reducing breakdown fluency in the blocked repetition condition only, suggesting that learners can capitalize on their memory for improving oral fluency by engaging in blocked practice.

The Effect of EN Pulsing Ratio and Repetition Frequency on the Bead Appearance and Microstructure Evolution in Aluminum Welding using Variable Polarity GMAW

This study addressed the gas metal arc welding (GMAW) of Al 5183 aluminum alloy using variable polarity (VP). The effects of the electrode negative (EN) pulsing ratio and repetition frequency on the geometrical features and microstructural evolution of the deposited materials were investigated and discussed. The current and voltage were manually controlled independently for each phase to evaluate the effect of the polarity change. The influence of phase and its changing frequency on the geometrical features and microstructure evolution were observed. The phase of the electrode affected the arc concentration and changed the amount of the deposited material and the dilution between the substrate. The EN phase is beneficial for making a finer structure than the electrode positive (EP) phase because of the lower heat input per unit mass. In addition, the size of the grains decreased as the phase change frequency increased. When the number of repetitions frequency increased within a cycle, the size of the microstructure was reduced. Consequently, strategies can be established to minimize the microstructure with VP-GMAW welding using a high EN pulsing ratio and low repetition conditions. Key words: Variable polarity, Gas metal arc welding, EN pulsing ratio, Repetition, Microstructure refining, aluminum

Cognitively demanding stimuli can acquire positive valence.

Generally, people tend to avoid stimuli that require mental effort; effort can generate negative emotions. However, employing mental effort can also promote positive emotions, given a successful outcome. We investigated whether the level of cognitive effort associated with stimuli will elicit positive or negative emotions. In Experiment 1, participants performed a gender Stroop task during the association phase. The actors from the Stroop task expressed emotionlessness, while half of the actors were displayed in the mostly incongruent (MI) condition and the rest in the mostly congruent (MC) condition. In the transfer phase, we used the same actors for the emotion discrimination task, and the actors expressed a positive emotion half of the time and a negative emotion for the other half. For the MI actors, participants responded faster to positive emotion than to negative emotion, but this difference was not significant for the MC actors. In Experiment 2, the association phase involved a task switching paradigm in which half of the actors were presented in the mostly switching (MS) condition and the other in the mostly repetition (MR) condition. In the transfer phase, the same individuals' faces were used for emotion discrimination. For the MS actors, but not the MR actors, the responses were faster to positive emotion than to negative emotion. Our results imply that stimuli associated with more cognitive effort (i.e., MI and MS stimuli) may be perceived as more positive after a successful outcome of a task, although future research is required to replicate these findings.

High power and high repetition frequency sub-nanosecond pulse generator with two-phase immersion cooling technique.

In this paper, a 60-stage Marx circuit with the two-phase immersion cooling technique is presented. The performance parameters of the pulse generator with phase change immersion cooling and forced air cooling are compared. The results show that the maximum repetition rate is increased from 80 to 260 kHz, the pulse drift is significantly reduced from 900 to 200ps, and the temperature rise of transistors is controlled effectively to enhance the stability of the amplitude. We also studied the influence of temperature on the turn-on and turn-off processes of the transistors to show the importance of heat management under high repetition conditions. Finally, a pulse generator is developed with the repetition rate of 200 kHz, the rise time of 180ps, and the amplitude of 2350V on a matched 50 Ω resistive load, which can work for more than 30min.