Memory Control Research Articles

Working memory and inhibitory control deficits in children with ADHD: an experimental evaluation of competing model predictions.

Children with ADHD demonstrate difficulties on many different neuropsychological tests. However, it remains unclear whether this pattern reflects a large number of distinct deficits or a small number of deficit(s) that broadly impact test performance. The current study is among the first experiments to systematically manipulate demands on both working memory and inhibition, with implications for competing conceptual models of ADHD pathogenesis. A clinically evaluated, carefully phenotyped sample of 110 children with ADHD, anxiety disorders, or co-occurring ADHD+anxiety (Mage=10.35, 44 girls; 69% White Not Hispanic/Latino) completed a counterbalanced, double dissociation experiment, with two tasks each per inhibition (low vs. high) x working memory (low vs. high) condition. Bayesian and frequentist models converged in indicating that both manipulations successfully increased demands on their target executive function (BF10>5.33x108, p<.001). Importantly, occupying children's limited capacity working memory system produced slower response times and reduced accuracy on inhibition tasks (BF10>317.42, p<.001, d=0.67-1.53). It also appeared to differentially reduce inhibition (and non-inhibition) accuracy for children with ADHD relative to children with anxiety (BF10=2.03, p=.02, d=0.50). In contrast, there was strong evidence against models that view working memory deficits as secondary outcomes of underlying inhibition deficits in ADHD (BF01=18.52, p=.85). This pattern indicates that working memory broadly affects children's ability to inhibit prepotent tendencies and maintain fast/accurate performance, and may explain the errors that children with ADHD make on inhibition tests. These findings are broadly consistent with models describing working memory as a causal mechanism that gives rise to secondary impairments. In contrast, these findings provide evidence against models that view disinhibition as a cause of working memory difficulties or view working memory as a non-causal correlate or epiphenomenon in ADHD.

Early childhood trauma exposure and neurocognitive and emotional processes: Associations in young children in a partial hospital program.

Early childhood trauma has been linked to neurocognitive and emotional processing deficits in older children, yet much less is known about these associations in young children. Early childhood is an important developmental period in which to examine relations between trauma and executive functioning/emotion reactivity, given that these capacities are rapidly developing and are potential transdiagnostic factors implicated in the development of psychopathology. This cross-sectional study examined associations between cumulative trauma, interpersonal trauma, and components of executive functioning, episodic memory, and emotion reactivity, conceptualized using the RDoC framework and assessed with observational and performance-based measures, in a sample of 90 children (ages 4-7) admitted to a partial hospital program. Children who had experienced two or more categories of trauma had lower scores in episodic memory, global cognition, and inhibitory control as measured in a relational (but not computerized) task, when compared to children with less or no trauma. Interpersonal trauma was similarly associated with global cognition and relational inhibitory control. Family contextual factors did not moderate associations. Findings support examining inhibitory control in both relationally significant and decontextualized paradigms in early childhood, and underscore the importance of investigating multiple neurocognitive and emotional processes simultaneously to identify potential targets for early intervention.

Fluid Cognition Among Individuals With Systemic Lupus Erythematosus.

We sought to describe fluid cognition and its correlates among individuals with systemic lupus erythematosus (SLE). Participants (n = 199) were recruited from a population-based cohort for a single study visit (October 2019 to May 2022). Fluid cognition was measured via the National Institutes of Health Toolbox Fluid Cognition Battery (including episodic memory, working memory, attention and inhibitory control, processing speed, and cognitive flexibility domains) and expressed as age-corrected standard scores (mean 100, SD 15). Potential impairment was defined as a standard score >1.5 SD below the mean. Descriptive statistics were calculated and associations of various participant characteristics with the potential fluid cognition impairment were assessed with multivariable logistic regression. Participants' mean age was 46.1 years; most were female (87.4%), Black (86.4%), and non-Hispanic (95.0%). The mean overall fluid cognition score was 87.2; of the individual domains, the participants' mean score was lowest on attention and inhibitory control (82.0). Working status (odds ratio [OR] 0.30, 95% confidence interval [CI] 0.14-0.64) and higher self-reported physical functioning (OR 0.46, 95% CI 0.28-0.75) and physical performance (OR 0.72, 95% CI 0.59-0.87) were associated with lower odds of fluid cognition impairment; lower educational attainment was associated with higher odds (OR 3.82, 95% CI 1.67-8.75). Self-reported forgetfulness, neuropsychiatric damage, and depressive symptoms were not statistically significantly associated with potential impairment. Fluid cognition and, particularly, attention and inhibitory control were low in those with SLE relative to the general US population. Working status, higher physical functioning and performance, and higher educational attainment were associated with lower prevalence of potential impairment. Future work is needed to develop and implement interventions to help support cognition in individuals with SLE.

Individual differences in representational gesture production are associated with cognitive and empathy skills.

Substantial individual variation exists in the frequency of gestures produced while speaking. This study investigated the associations between cognitive abilities, empathy levels, and personality traits with the frequency of representational gestures. A cartoon narration task and a social dilemma solving task were used to elicit gestures. Predictor variables were selected based on prior research on individual differences in gesture production and the cognitive and communicative functions of gestures in speech. Our findings revealed that an increased frequency of representational gestures was associated with higher empathy levels in the cartoon narration task. However, in the social dilemma solving task, a higher frequency of representational gestures was associated with lower visuospatial working memory, spatial transformation, and inhibition control abilities. Moreover, no significant relationships were found between verbal working memory, personality traits, and the frequency of representational gestures in either task. These findings suggested that predictor variables for representational gesture production vary depending on the nature of the gesture elicitation task (e.g., spatiomotoric vs. abstract topics). Future research should examine the relationship between individuals' cognitive abilities, empathy and gesture production with across a broader range of topics and in more ecologically valid contexts.

Memory control immediately improves unpleasant emotions associated with autobiographical memories of past immoral actions

ABSTRACT The ability to stop unwanted memories from coming to mind is theorised to be essential for maintaining good mental health. People can employ intentional strategies to prevent conscious intrusions of negative memories, and repeated attempts to stop retrieval both reduces the frequency of intrusions and improves subsequent emotions elicited by those memories. However, it is still unknown whether memory control can improve negative emotions immediately, at the time control is attempted. It is also not clear which strategy is most beneficial for emotion regulation; clearing the mind of any thoughts of negative memories via direct suppression, or substituting memory recall with alternative thoughts. Here, we provide novel evidence that memory control immediately regulates negative emotions associated with autobiographical memories of morally wrong actions. Repeated control significantly improved negative emotions over time, regardless of the strategy used to implement control. Thought substitution involving either positive diversionary thinking or counterfactual thinking both induced positive feelings, whereas direct suppression neutralised emotions, regardless of whether memories were positive or negative. These empirical findings have implications for clinical practice as they indicate that memory control strategies could be effective emotion regulation methods for real-world intrusive memories.

Inhibition and working memory capacity modulate the mental space-time association.

This research aimed to investigate whether the mental space-time association of temporal concepts could be modulated by the availability of cognitive resources (in terms of working memory and inhibitory control capacities) and to explore whether access to this association could be an automatic process. To achieve this, two experiments were carried out. In Experiment 1, participants had to classify words with future and past meanings. The working memory load (high vs. low) was manipulated and the participants were grouped into quartiles according to their visuospatial working memory capacity (WMC). Temporal concepts were displayed subliminally (immediate masking) and supraliminally (delayed masking). The ANOVA showed a performance pattern consistent with the left-past right-future conceptual scheme, regardless of both the type of masking and the working memory load, except in high WMC participants, in which, interestingly, the space-time association effect was absent. In Experiment 2, participants were asked to respond to the colour of the font of the temporal words, and their attentional control capacity was assessed. The results indicated a timeline effect that was irrespective of the WM load and the type of perceptual processing, but not of the WM capacity or the inhibitory abilities. These findings partially endorse the automatic and implicit access to the mental space-time association and suggest the involvement of the availability of cognitive resources. Individual WMC differences appear to modulate the automatic nature of the effect rather than the processing conditions themselves.

Blocked versus interleaved: How range contexts modulate time perception and its EEG signatures.

Accurate time perception is a crucial element in a wide range of cognitive tasks, including decision-making, memory, and motor control. One commonly observed phenomenon is that when given a range of time intervals to consider, people's estimates often cluster around the midpoint of those intervals. Previous studies have suggested that the range of these intervals can also influence our judgments, but the neural mechanisms behind this "range effect" are not yet understood. We used both behavioral tests and electroencephalographic (EEG) measures to understand how the range of sample time intervals affects the accuracy of people's subsequent time estimates. Study participants were exposed to two different setups: In the "blocked-range" (BR) session, short and long intervals were presented in separate blocks, whereas in the "interleaved-range" (IR) session, intervals of various lengths were presented randomly. Our findings indicated that the BR context led to more accurate time estimates compared to the IR context. In terms of EEG data, the BR context resulted in quicker buildup of contingent negative variation (CNV), which also reached higher amplitude levels and dissolved more rapidly during the encoding stage. We also observed an enhanced amplitude in the offset P2 component of the EEG signal. Overall, our results suggest that the variability in time intervals, as defined by their range, influences the neural processes that underlie time estimation.

A working memory intervention for children with prenatal alcohol exposure: Pilot study

Cogmed© is a computerized working memory training program designed to improve attention and working memory. We examined the short- and long-term impacts of a 25-session Cogmed© intervention on working memory and other cognitive and learning domains in children with prenatal alcohol exposure (PAE) and typically developing children. Participants included 38 children (4 - 13 years old) from Alberta, Canada in two groups: PAE (n = 20) and typically developing (n = 18). Significant improvements in areas of working memory and attentional control for both the PAE and the typically developing group were reported immediately after intervention completion (short-term impact). The gains on some measures were retained at five-week follow up (long-term impact). Preliminary findings indicate that computerized interventions may positively impact WM and attention control and that these changes may be maintained after a delay period.

What insights can response times provide for education research?

ABSTRACT The main objective of this methodological article is to discuss the contribution of response times as a tool in education research. The use of response times in research is largely a legacy of the work carried out in cognitive psychology, which has made it possible to describe the cognitive processes involved in information processing. In education, research that incorporates response times into its methodological design often has two main objectives: 1) evaluate the automation of basic learning and 2) infer the cognitive processes involved in academic learning, such as working memory and inhibitory control. This article addresses and discusses specific research designs that use response times across various academic disciplines and instructional levels, offering a comprehensive overview of the potential applications of response times in education research. In light of this overview, utilizing response times in education research not only emerges as relevant but also serves to complement existing methodological tools. For instance, such designs can aid in identifying the relative difficulty of different types of learning, understanding the underlying reasons for such variations, and offering valuable insights for developing learning sequences and pedagogical interventions that are more consistent with learning processes.

Optimal metacognitive control of memory recall.

Most of us have experienced moments when we could not recall some piece of information but felt that it was just out of reach. Research in metamemory has established that such judgments are often accurate; but what adaptive purpose do they serve? Here, we present an optimal model of how metacognitive monitoring (feeling of knowing) could dynamically inform metacognitive control of memory (the direction of retrieval efforts). In two experiments, we find that, consistent with the optimal model, people report having a stronger memory for targets they are likely to recall and direct their search efforts accordingly, cutting off the search when it is unlikely to succeed and prioritizing the search for stronger memories. Our results suggest that metamemory is indeed adaptive and motivate the development of process-level theories that account for the dynamic interplay between monitoring and control. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Oral administration of phytochemicals protects honey bees against cognitive and motor impairments induced by the insecticide fipronil.

Pollution produced by exposure to pesticides is a major concern for food security because the negative impacts on pollinators. Fipronil, an insecticide broadly used around the globe has been associated with the ongoing decline of bees. With a characteristic neuroactive toxicodynamic, fipronil leads to cognitive and motor impairments at sublethal dosages. Despite of regional bans, multilevel strategies are necessary for the protection of pollinators. Recent evidence suggests that specific nutrients in the diets of bees may induce protection against insecticides. Here, we evaluated whether the administration of three phytochemicals, namely rutin, kaempferol and p-coumaric acid provide protection to the Africanized honey bee Apis mellifera against oral administration of realistic dosages of fipronil. We tested the potential impairment produced by fipronil and the protection induced by the phytochemicals in learning, 24h memory, sucrose sensitivity and motor control. We found that the administration of fipronil induced a concentration-dependent impairment in learning and motor control, but not 24h memory or sucrose sensitivity across a 24h window. We also found that the administration of rutin, p-coumaric acid, kaempferol and the mixture was innocuous and generally offered protection against the impairments induced by fipronil. Overall, our results indicate that bees can be prophylactically protected against insecticides via nutrition, providing an alternative to the ongoing conflict between the use of insecticides and the decline of pollinators. As the studied phytochemicals are broadly present in nectar and pollen, our results suggest that the nutritional composition, and not only its production, should be considered when implementing strategies of conservation via gardens and co-cropping.

Comparison of Executive Function Skills between Patients with Cerebral Palsy and Typically Developing Populations: A Systematic Review and Meta-Analysis.

Background: Children with CP show deficits in executive function compared to their typically developing peers, based on the majority of the available evidence. However, the magnitude of these deficits, as well as the proportions of the shortfalls in the three main components, have not yet been examined. This is the first meta-analysis to synthesize evidence on the magnitude of differences between patients with cerebral palsy (CP) and typically developing populations in different components of executive function skills (working memory, inhibitory control and cognitive flexibility), and thus makes recommendations on which areas of executive functioning are in greatest need of intervention. Methods: We conducted a systematic literature search of four databases for studies that measured executive functions in these two groups until 31 August 2023. We calculated the standardized mean difference (Hedges' g), an average effect size overall, and for the three components of executive function skills separately, we used several moderator analyses, including methodological differences between the primary studies. Results: Fifteen articles were included in the meta-analysis. The average mean difference in executive functioning overall was large (g+ = -0.82). Furthermore, large significant differences were found in working memory (g+ = -0.92) and inhibitory control (g+ = -0.82) and a moderate difference was identified in cognitive flexibility (g+ = -0.57). In addition, results of moderator analyses reveal the importance of a rigorous matching of control group participants and CP patients. Conclusions: The results demonstrate a severe impairment in all executive functions among CP patients compared to typically developing peers, which do not decrease over time.

Mental workload assessment by monitoring brain, heart, and eye with six biomedical modalities during six cognitive tasks.

The efficiency and safety of complex high precision human-machine systems such as in aerospace and robotic surgery are closely related to the cognitive readiness, ability to manage workload, and situational awareness of their operators. Accurate assessment of mental workload could help in preventing operator error and allow for pertinent intervention by predicting performance declines that can arise from either work overload or under stimulation. Neuroergonomic approaches based on measures of human body and brain activity collectively can provide sensitive and reliable assessment of human mental workload in complex training and work environments. In this study, we developed a new six-cognitive-domain task protocol, coupling it with six biomedical monitoring modalities to concurrently capture performance and cognitive workload correlates across a longitudinal multi-day investigation. Utilizing two distinct modalities for each aspect of cardiac activity (ECG and PPG), ocular activity (EOG and eye-tracking), and brain activity (EEG and fNIRS), 23 participants engaged in four sessions over 4 weeks, performing tasks associated with working memory, vigilance, risk assessment, shifting attention, situation awareness, and inhibitory control. The results revealed varying levels of sensitivity to workload within each modality. While certain measures exhibited consistency across tasks, neuroimaging modalities, in particular, unveiled meaningful differences between task conditions and cognitive domains. This is the first comprehensive comparison of these six brain-body measures across multiple days and cognitive domains. The findings underscore the potential of wearable brain and body sensing methods for evaluating mental workload. Such comprehensive neuroergonomic assessment can inform development of next generation neuroadaptive interfaces and training approaches for more efficient human-machine interaction and operator skill acquisition.

Disorder-specific versus transdiagnostic cognitive mechanisms in anxiety and depression: Machine-learning-based prediction of symptom severity

IntroductionPsychiatric evaluation of anxiety and depression is currently based on self-reported symptoms and their classification into discrete disorders. Yet the substantial overlap between these disorders as well as their within-disorder heterogeneity may contribute to the mediocre success rates of treatments. The proposed research examines a new framework for diagnosis that is based on alterations in underlying cognitive mechanisms. In line with the Research Domain Criteria (RDoC) approach, the current study directly compares disorder-specific and transdiagnostic cognitive patterns in predicting the severity of anxiety and depression symptoms. MethodsThe sample included 237 individuals exhibiting differing levels of anxiety and depression symptoms, as measured by the STAI-T and BDI-II. Random Forest regressors were used to analyze their performance on a battery of six computerized cognitive-behavioral tests targeting selective and spatial attention, expectancy, interpretation, memory, and cognitive control biases. ResultsUnique anxiety-specific biases were found, as well as shared anxious-depressed bias patterns. These cognitive biases exhibited relatively high fitting rates when predicting symptom severity (questionnaire scores common range 0–60, MAE = 6.03, RMSE = 7.53). Interpretation and expectancy biases exhibited the highest association with symptoms, above all other individual biases. LimitationsAlthough internal validation methods were applied, models may suffer from potential overfitting due to sample size limitations. ConclusionIn the context of the ongoing dispute regarding symptom-centered versus transdiagnostic approaches, the current study provides a unique comparison of these two views, yielding a novel intermediate approach. The results support the use of mechanism-based dimensional diagnosis for adding precision and objectivity to future psychiatric evaluations.

Number sense predicts arithmetic competence in young Chinese children: the role of visual spatial skills and inhibitory control

ABSTRACT To examine the relationship between early number sense and later symbolic arithmetic competence and how they are connected in young Chinese children. The present study utilized a longitudinal sample of 115 Chinese children aged 3 to 6. Young children completed measures to assess number sense, visual spatial skills (in the fall of their second kindergarten year, K2), arithmetic competence (in the spring of their second kindergarten year, K3), working memory, verbal comprehension, and inhibitory control (in the fall of their first kindergarten year, K1). The results showed that number sense predicted arithmetic competence six months later. Meanwhile, visual spatial skills played a mediating role in this association, but it became non-significant when working memory, verbal comprehension, and inhibitory control were added as covariates. These longitudinal findings confirm the close association between number sense and arithmetic competence in young Chinese children.

New Insights on Bidirectional Associative Memory Neural Networks with Leakage Delay Components and Time-Varying Delays Using Sampled-Data Control

The sampling data control of bidirectional associative memory (BAM) neural network with leakage delay is considered in this article. The BAM model is viewed as a mixed delay that combines a distributed delay, a discrete delay that varies over time, and a delay in the leaking period. The sampling system is then converted to a continuous time-delay system using an input delay method. In order to get adequate conditions in the form of linear matrix inequalities(LMIs), we build a new Lyapunov-Krasovskii Functional (LKF) in conjunction with the free weight matrix approach. Finally, a simulation results are given to show the efficiency of the theoretical approach.

The Long and Winding Road to Real-Life Experiments: Remote Assessment of Executive Functions with Computerized Games-Results from 8 Years of Naturalistic Interventions.

Mate Marote is an open-access cognitive training software aimed at children between 4 and 8 years old. It consists of a set of computerized games specifically tailored to train and evaluate Executive Functions (EF), a class of processes critical for purposeful, goal-directed behavior, including working memory, planning, flexibility, and inhibitory control. Since 2008, several studies were performed with this software at children's own schools in interventions supervised in-person by cognitive scientists. After 2015, we incorporated naturalistic, yet controlled, interventions with children's own teachers' help. The platform includes a battery of standardized tests, disguised as games, to assess children's EF. The main question that emerges is whether the results, obtained with these traditional tasks but conducted without the presence of researchers, are comparable to those widely reported in the literature, that were obtained in more supervised settings. In this study, we were able to replicate the expected difficulty and age effects in at least one of the analyzed dependent variables of each employed test. We also report important discrepancies between the expected and the observed response time patterns, specifically for time-constrained tasks. We hereby discuss the benefits and setbacks of a new possible strategy for this type of assessment in naturalistic settings. We conclude that this battery of established EF tasks adapted for its remote usage is appropriate to measure the expected mental processes in naturalistic settings, enriching opportunities to upscale cognitive training interventions at schools. These types of tools can constitute a concerted strategy to bring together educational neuroscience research and real-life practice.

Be prepared for interruptions: EEG correlates of anticipation when dealing with task interruptions and the role of aging

Dealing with task interruptions requires the flexible use of working memory and attentional control mechanisms, which are prone to age-related changes. We investigated effects of age on dealing with task interruptions and potential advantages of anticipating an interruption using EEG and a retrospective cueing (retro-cue) paradigm. Thirty-two young (18–30 years) and 28 older (55–70 years) participants performed a visual working memory task, where they had to report the orientation of a target following a retro-cue. Within blocks of 10 trials, they were always, never, or randomly interrupted with an arithmetic task before the onset of the retro-cue. The interruption-induced decline in primary task performance was more pronounced in older participants, while only these benefited from anticipation. The EEG analysis revealed reduced theta and alpha/beta response to the retro-cue following interruptions, especially for the older participants. In both groups, anticipated interruptions were associated with increased theta and alpha/beta power prior and during the interruption, and stronger beta suppression to the retro-cue. The results indicate that interruptions impede the refocusing of attention on the task-relevant representation of the primary task, especially in older people, while anticipation facilitates preparation for the interruption task and resumption of the primary task.

Cryptanalysis of QARMAv2

QARMAv2 is a general-purpose and hardware-oriented family of lightweight tweakable block ciphers (TBCs) introduced in ToSC 2023. QARMAv2, as a redesign of QARMAv1 with a longer tweak and tighter security margins, is also designed to be suitable for cryptographic memory protection and control flow integrity. The designers of QARMAv2 provided a relatively comprehensive security analysis in the design specification, e.g., some bounds for the number of attacked rounds in differential and boomerang analysis, together with some concrete impossible differential, zerocorrelation, and integral distinguishers. As one of the first third-party cryptanalysis of QARMAv2, Hadipour et al., [HGSE24] significantly improved the integral distinguishers of QARMAv2, and provided the longest concrete distinguishers of QARMAv2 up to now. However, they provided no key recovery attack based on their distinguishers. This paper delves into the cryptanalysis of QARMAv2 to enhance our understanding of its security. Given that the integral distinguishers of QARMAv2 are the longest concrete distinguishers for this cipher so far, we focus on integral attack. To this end, we first further improve the automatic tool introduced by Hadipour et al. [HSE23,HGSE24] for finding integral distinguishers of TBCs following the TWEAKEY framework. This new tool exploits the MixColumns property of QARMAv2 to find integral distinguishers more suitable for key recovery attacks. Then, we combine several techniques for integral key recovery attacks, e.g., Meet-in-the-middle and partial-sum techniques to build a fine-grained integral key recovery attack on QARMAv2. Notably, we demonstrate how to leverage the low data complexity of the integral distinguishers of QARMAv2 to reduce the memory complexity of the meet-in-the-middle technique. As a result, we successfully present the first concrete key recovery attacks on reduced-round versions of QARMAv2. This includes attacking 13 rounds of QARMAv2-64-128 with a single tweak block (T = 1), 14 rounds of QARMAv2-64-128 with two independent tweak blocks (T = 2), and 16 rounds of QARMAv2-128-256 with two independent tweak blocks (T = 2), all in an unbalanced setting. Our attacks do not compromise the claimed security of QARMAv2, but they shed more light on the cryptanalysis of this cipher.

Neurocognitive Errors and Noncontact Anterior Cruciate Ligament Injuries in Professional Male Soccer Players.

Evidence is emerging that core neurocognitive functions such as working memory and inhibitory control (ie, motor-response and attentional inhibition) are linked to the anterior cruciate ligament (ACL) injury risk. Research has been conducted in laboratory settings, but the contribution of neurocognition to actual ACL injuries under real-world conditions is unknown. To describe the possible neurocognitive errors involved in noncontact ACL injury mechanisms. Case series. Soccer matches. A total of 47 professional male soccer players. Three independent reviewers evaluated 47 videos of players sustaining noncontact ACL injuries. Neurocognitive errors in inhibitory control were operationalized as follows: (1) motor-response inhibition was scored when a player demonstrated poor decision-making and approached the opponent with high speed that reduced the ability to stop or change the intended action and (2) an attentional error was scored when a player shifted his selective attention away from the relevant task to irrelevant stimuli. Of 47 noncontact ACL injuries, 26 (55%) were related to a pressing-type injury, 19 (73%) of which involved a deceiving action made by the opponent, suggesting poor inhibitory control of the defender. Of the remaining 21 noncontact ACL injuries (45%), 16 (76%) could be attributed to attentional errors. Agreement among the 3 raters was very good for all items except poor decision-making, which showed fair to good agreement (Fleiss κ = 0.71). Interrater reliability was excellent (intraclass correlation coefficient = 0.99-1.00). Errors in motor-response inhibitory control and attentional inhibition were common during noncontact ACL injury events in professional male soccer players. The interrater agreement in detecting neurocognitive errors in general was very good.