Learning Trials Research Articles

Verbal Encoding Deficits Impact Recognition Memory in Atypical "Non-Amnestic" Alzheimer's Disease.

Memory encoding and retrieval deficits have been identified in atypical Alzheimer’s disease (AD), including posterior cortical atrophy (PCA) and logopenic variant primary progressive aphasia (lvPPA), despite these groups being referred to as “non-amnestic”. There is a critical need to better understand recognition memory in atypical AD. We investigated performance on the California Verbal Learning Test (CVLT-II-SF) in 23 amyloid-positive, tau-positive, and neurodegeneration-positive participants with atypical “non-amnestic” variants of AD (14 PCA, 9 lvPPA) and 14 amnestic AD participants. Recognition memory performance was poor across AD subgroups but trended toward worse in the amnestic group. Encoding was related to recognition memory in non-amnestic but not in amnestic AD. We also observed cortical atrophy in dissociable subregions of the distributed memory network related to encoding (left middle temporal and angular gyri, posterior cingulate and precuneus) compared to recognition memory (anterior medial temporal cortex). We conclude that recognition memory is not spared in all patients with atypical variants of AD traditionally thought to be “non-amnestic”. The non-amnestic AD patients with poor recognition memory were those who struggled to encode the material during the learning trials. In contrast, the amnestic AD group had poor recognition memory regardless of encoding ability.

Visuomotor Adaptation of Lower Extremity Movements During Virtual Ball-Kicking Task.

Sophisticated soccer players can skillfully manipulate a ball with their feet depending on the external environment. This ability of goal-directed control in the lower limbs has not been fully elucidated, although upper limb movements have been studied extensively using motor adaptation tasks. The purpose of this study was to clarify how the goal-directed movements of the lower limbs is acquired by conducting an experiment of visuomotor adaptation in ball-kicking movements. In this study, healthy young participants with and without experience playing soccer or futsal performed ball-kicking movements. They were instructed to move a cursor representing the right foot position and shoot a virtual ball to a target on a display in front of them. During the learning trials, the trajectories of the virtual ball were rotated by 15° either clockwise or counterclockwise relative to the actual ball direction. As a result, participants adapted their lower limb movements to novel visuomotor perturbation regardless of the soccer playing experience, and changed their whole trajectories not just the kicking position during adaptation. These results indicate that the goal-directed lower limb movements can be adapted to the novel environment. Moreover, it was suggested that fundamental structure of visuomotor adaptation is common between goal-directed movements in the upper and lower limbs.

Development of Virtual Blended Learning Based on Edmodo with Problem-Solving for Basic Physics

This research is based on the problem of changing learning patterns from face to face to online due to the COVID-19 pandemic. The objectives of this study were to develop virtual blended learning based on Edmodo with problem solving in Basic Physics courses and to describe the effectiveness of product based on trials data analysis. This research was conducted in Ngada Regency, East Nusa Tenggara province. The subjects in this study were the lecturers and students of the STKIP Citra Bakti science education study program. The measured aspect was the quality of the virtual blended learning product consists of content, presentation, and language which developed following the problem-solving learning model phase. The data obtained in this study were analyzed descriptively qualitatively to explain product quality. This product was developed with the ADDIE model proposed by Lee and Owen. The results showed that the product development had reached the evaluation stage with a mean validation score of 4.53 and was in the very good category. Otherwise, the quality of the results of the virtual blended learning trial based on problem solving from lecturers and students is in the very good category. Based on the information, developed virtual blended learning based on Edmodo with problem- solving was good to be implemented in Basic Physics courses.

GRAN3SAT: Creating Flexible Higher-Order Logic Satisfiability in the Discrete Hopfield Neural Network

One of the main problems in representing information in the form of nonsystematic logic is the lack of flexibility, which leads to potential overfitting. Although nonsystematic logic improves the representation of the conventional k Satisfiability, the formulations of the first, second, and third-order logical structures are very predictable. This paper proposed a novel higher-order logical structure, named G-Type Random k Satisfiability, by capitalizing the new random feature of the first, second, and third-order clauses. The proposed logic was implemented into the Discrete Hopfield Neural Network as a symbolic logical rule. The proposed logic in Discrete Hopfield Neural Networks was evaluated using different parameter settings, such as different orders of clauses, different proportions between positive and negative literals, relaxation, and differing numbers of learning trials. Each evaluation utilized various performance metrics, such as learning error, testing error, weight error, energy analysis, and similarity analysis. In addition, the flexibility of the proposed logic was compared with current state-of-the-art logic rules. Based on the simulation, the proposed logic was reported to be more flexible, and produced higher solution diversity.

Continuous Online Adaptation of Bioinspired Adaptive Neuroendocrine Control for Autonomous Walking Robots.

Walking animals can continuously adapt their locomotion to deal with unpredictable changing environments. They can also take proactive steps to avoid colliding with an obstacle. In this study, we aim to realize such features for autonomous walking robots so that they can efficiently traverse complex terrains. To achieve this, we propose novel bioinspired adaptive neuroendocrine control. In contrast to conventional locomotion control methods, this approach does not require robot and environmental models, exteroceptive feedback, or multiple learning trials. It integrates three main modular neural mechanisms, relying only on proprioceptive feedback and short-term memory, namely: 1) neural central pattern generator (CPG)-based control; 2) an artificial hormone network (AHN); and 3) unsupervised input correlation-based learning (ICO). The neural CPG-based control creates insect-like gaits, while the AHN can continuously adapt robot joint movement individually with respect to the terrain during the stance phase using only the torque feedback. In parallel, the ICO generates short-term memory for proactive obstacle negotiation during the swing phase, allowing the posterior legs to step over the obstacle before hitting it. The control approach is evaluated on a bioinspired hexapod robot walking on complex unpredictable terrains (e.g., gravel, grass, and extreme random stepfield). The results show that the robot can successfully perform energy-efficient autonomous locomotion and online continuous adaptation with proactivity to overcome such terrains. Since our adaptive neural control approach does not require a robot model, it is general and can be applied to other bioinspired walking robots to achieve a similar adaptive, autonomous, and versatile function.

Neural Control and Online Learning for Speed Adaptation of Unmanned Aerial Vehicles.

Unmanned aerial vehicles (UAVs) are involved in critical tasks such as inspection and exploration. Thus, they have to perform several intelligent functions. Various control approaches have been proposed to implement these functions. Most classical UAV control approaches, such as model predictive control, require a dynamic model to determine the optimal control parameters. Other control approaches use machine learning techniques that require multiple learning trials to obtain the proper control parameters. All these approaches are computationally expensive. Our goal is to develop an efficient control system for UAVs that does not require a dynamic model and allows them to learn control parameters online with only a few trials and inexpensive computations. To achieve this, we developed a neural control method with fast online learning. Neural control is based on a three-neuron network, whereas the online learning algorithm is derived from a neural correlation-based learning principle with predictive and reflexive sensory information. This neural control technique is used here for the speed adaptation of the UAV. The control technique relies on a simple input signal from a compact optical distance measurement sensor that can be converted into predictive and reflexive sensory information for the learning algorithm. Such speed adaptation is a fundamental function that can be used as part of other complex control functions, such as obstacle avoidance. The proposed technique was implemented on a real UAV system. Consequently, the UAV can quickly learn within 3–4 trials to proactively adapt its flying speed to brake at a safe distance from the obstacle or target in the horizontal and vertical planes. This speed adaptation is also robust against wind perturbation. We also demonstrated a combination of speed adaptation and obstacle avoidance for UAV navigations, which is an important intelligent function toward inspection and exploration.

Atorvastatin reduces alloxan-induced impairment of aversive stimulus memory in mice.

An association between dysregulated glucose levels in patients with diabetes mellitus and detrimental effects on the central nervous system, particularly in Alzheimer disease, has been recognized. Atorvastatin treatment has improved memory and cognition in some patients with diabetes mellitus and Alzheimer disease. To determine possible neuroprotective effects of atorvastatin on memory and cognition by measuring changes in an adverse stimulus avoidance learning deficit induced by alloxan in a murine model of diabetes mellitus and impaired memory and cognition. We administered 150 mg/kg and 100 mg/kg alloxan in saline (intraperitoneally, i.p.) at a 48 h interval to produce a model of diabetes mellitus in male BALB/c mice. An oral glucose tolerance test (OGTT) was used to assess blood glucose regulation. After demonstrating hyperglycemia in mice (n = 7 per group) we administered vehicle (saline, i.p.), atorvastatin (10 mg/kg, i.p.), or liraglutide (200 μg/kg, i.p.) for 28 d except for those in a negative control group, which were given saline instead of alloxan, and a group administered atorvastatin alone, which were given saline instead of alloxan followed by atorvastatin (10 mg/kg, i.p.) for 28 d. Locomotor activity was measured 24 h after the final drug treatments, and subsequently their learned behavioral response to an adverse electrical stimulus to their plantar paw surface in a dark compartment was measured using a passive avoidance apparatus (Ugo Basile) in a model of impaired memory and cognition associated with Alzheimer disease. To determine any deficit in their learned avoidance of the adverse stimulus, we measured the initial latency or time mice spent in an illuminated white compartment before entering the dark compartment in the learning trial, and on the day after learning to avoid the adverse stimulus, the retention period latency in the light compartment and time spent in the dark compartment. Atorvastatin alone produced no significant change in blood glucose levels (F4,10 = 0.80, P = 0.55) within 2 h. Liraglutide decreased blood glucose levels after 0.5 h (F4,10 = 11.7, P < 0.001). We found no significant change in locomotor activity in any group. In mice with alloxan-induced diabetes, atorvastatin significantly attenuated the decreased avoidance associated with the diabetes (F4,30 = 38.0, P = 0.02) and liraglutide also significantly attenuated the decreased avoidance (F4,30 = 38.0, P < 0.001). Atorvastatin alone had no significant effect on the adversive learned response compared with vehicle treatment (F4,30 = 38.0, P > 0.05). Atorvastatin significantly decreased the time mice with alloxan-induced diabetes spent in the dark compartment compared with mice in the diabetes group without atorvastatin treatment (F4,30 = 53.9, P = 0.046). Liraglutide also significantly reduced the time mice with alloxan-induced diabetes spent in the dark compartment compared with vehicle-treated mice with alloxan-induced diabetes (F4,30 = 53.9, P < 0.001). Atorvastatin treatment alone had no significant effect on the time mice spent in dark compartment compared with the control group (F4,30 = 53.9, P > 0.05). Atorvastatin significantly attenuated the adverse stimulus avoidance learning deficit in the alloxan-induced murine model of diabetes suggesting decreased impairment of memory and cognition.

LAG-1: A dynamic, integrative model of learning, attention, and gaze.

It is clear that learning and attention interact, but it is an ongoing challenge to integrate their psychological and neurophysiological descriptions. Here we introduce LAG-1, a dynamic neural field model of learning, attention and gaze, that we fit to human learning and eye-movement data from two category learning experiments. LAG-1 comprises three control systems: one for visuospatial attention, one for saccadic timing and control, and one for category learning. The model is able to extract a kind of information gain from pairwise differences in simple associations between visual features and categories. Providing this gain as a reentrant signal with bottom-up visual information, and in top-down spatial priority, appropriately influences the initiation of saccades. LAG-1 provides a moment-by-moment simulation of the interactions of learning and gaze, and thus simultaneously produces phenomena on many timescales, from the duration of saccades and gaze fixations, to the response times for trials, to the slow optimization of attention toward task relevant information across a whole experiment. With only three free parameters (learning rate, trial impatience, and fixation impatience) LAG-1 produces qualitatively correct fits for learning, behavioural timing and eye movement measures, and also for previously unmodelled empirical phenomena (e.g., fixation orders showing stimulus-specific attention, and decreasing fixation counts during feedback). Because LAG-1 is built to capture attention and gaze generally, we demonstrate how it can be applied to other phenomena of visual cognition such as the free viewing of visual stimuli, visual search, and covert attention.

Biogenic amines mediate learning success in appetitive odor conditioning in honeybees

ObjectivesBiogenic amines modulate the honeybees' behavioral development, especially olfactory learning behavior. Diverse behavioral protocols have been developed to investigate the olfactory learning behavior of bees to process appetitive olfaction information. Apis mellifera ligustica is a well-known eusocial insect to examine the olfactory learning behavior. This study evaluated the relationship between olfactory learning success and biogenic amines and uncovered the role of biogenic amines to regulate the olfactory learning behavior of bees. MethodsWe used high-performance liquid chromatography (HPLC) with an electrochemical detection (ECD) system to quantify neurotransmitters levels in the bee brain following olfactory learning trials. Furthermore, the bees of the control group and the dopamine flupenthixol blocker injected group were trained to evaluate the olfactory learning performance. ResultsOur finding showed that learning success was directly correlated with the levels of DA and serotonin (5-HT), furthermore, bees of the control group showed higher proboscis extension response than dopamine blocker injected group. Taken together, these findings revealed that dopamine (DA) and serotonin (5-HT) could thus act together to define optimal motivational or attentional levels and improve learning success and indicated that dopamine blocker flupenthixol has to modulate influence on the olfactory learning performance of bees. ConclusionThe results strongly imply that biogenic amines can durably modify the learning behavior in future model insects.

A meta-analysis of peer-assisted learning on examination performance in clinical knowledge and skills education

BackgroundPeer-assisted learning is a method of active learning that is gaining traction throughout higher education. In the medical curriculum, peer-assisted learning has been the subject of independent studies collecting various types of data. However, an overall analysis of those studies providing objective measurements of the influence of peer-assisted learning could be particularly useful for teachers and students alike in a knowledge-heavy curriculum such as medicine. In this study we set out to analyse the efficacy of peer-assisted learning on medical students’ learning of clinical knowledge and skills that is assessed through some objective examination, and thereby define whether such approaches have a reproducible benefit for inclusion in the medical curriculum.MethodsDatabases including Pubmed, Embase and Science Direct were searched for relevant studies containing randomized controlled trials (RCTs) of peer-assisted learning published before July 29th ,2020. A meta-analysis was performed by using RevMan 5.3 software.ResultsThirteen studies involving 2,003 medical students were analyzed for clinical knowledge and skills gains that included some objective measurement of learning. The results of this meta-analysis indicated that considering all these studies together, peer-assisted learning leads to improvements in clinical knowledge and skills learning for medical students compared with traditional teacher-led passive learning. One study was found likely to be a source of significant heterogeneity, and when this was removed from the meta-analysis, the pooled effect was no longer statistically significant.ConclusionsPeer-assisted learning can be an effective method of learning applied to medical student education. Active learning through peer-assisted learning should be seen as complementary to teacher-led approaches. Two of the individual studies on peer-assisted learning show a statistically significant benefit on examination performance compared to the other studies considered, that either show negligible benefits or at worst no detriment in learning. This highlights the need for more high-quality and focused randomized control trials to identify those critical parameters that lead to improved student learning using such approaches.

Human motor learning is robust to control-dependent noise.

Noises are ubiquitous in sensorimotor interactions and contaminate the information provided to the central nervous system (CNS) for motor learning. An interesting question is how the CNS manages motor learning with imprecise information. Integrating ideas from reinforcement learning and adaptive optimal control, this paper develops a novel computational mechanism to explain the robustness of human motor learning to the imprecise information, caused by control-dependent noise that exists inherently in the sensorimotor systems. Starting from an initial admissible control policy, in each learning trial the mechanism collects and uses the noisy sensory data (caused by the control-dependent noise) to form an imprecise evaluation of the performance of the current policy and then constructs an updated policy based on the imprecise evaluation. As the number of learning trials increases, the generated policies mathematically provably converge to a (potentially small) neighborhood of the optimal policy under mild conditions, despite the imprecise information in the learning process. The mechanism directly synthesizes the policies from the sensory data, without identifying an internal forward model. Our preliminary computational results on two classic arm reaching tasks are in line with experimental observations reported in the literature. The model-free control principle proposed in the paper sheds more lights into the inherent robustness of human sensorimotor systems to the imprecise information, especially control-dependent noise, in the CNS.

Differential gene expression analysis following olfactory learning in honeybee (Apis mellifera L.).

Insects change their stimulus-response through the perception of associating these stimuli with important survival events such as rewards, threats, and mates. Insects develop strong associations and relate them to their experiences through several behavioral procedures. Among the insects, Apis species, Apis mellifera ligustica are known for their outstanding ability to learn with tremendous economic importance. Apis mellifera ligustica has a strong cognitive ability and promising model species for investigating the neurobiological basis of remarkable olfactory learning abilities. Here we evaluated the olfactory learning ability of A. mellifera by using the proboscis extension reflex (PER) protocol. The brains of the learner and failed-learner bees were examined for comparative transcriptome analysis by RNA-Seq to explain the difference in the learning capacity. In this study, we used an appetitive olfactory learning paradigm in the same age of A. mellifera bees to examine the differential gene expression in the brain of the learner and failed-learner. Bees that respond in 2nd and 3rd trials or only responded to 3rd trials were defined as learned bees, failed-learner individuals were those bees that did not respond in all learning trials The results indicate that the learning ability of learner bees was significantly higher than failed-learner bees for 12 days. We obtained approximately 46.7 and 46.4 million clean reads from the learner bees failed-learner bees, respectively. Gene expression profile between learners’ bees and failed-learners bees identified 74 differentially expressed genes, 57 genes up-regulated in the brains of learners and 17 genes were down-regulated in the brains of the bees that fail to learn. The qRT-PCR validated the differently expressed genes. Transcriptome analyses revealed that specific genes in learner and failed-learner bees either down-regulated or up-regulated play a crucial role in brain development and learning behavior. Our finding suggests that down-regulated genes of the brain involved in the integumentary system, storage proteins, brain development, sensory processing, and neurodegenerative disorder may result in reduced olfactory discrimination and olfactory sensitivity in failed-learner bees. This study aims to contribute to a better understanding of the olfactory learning behavior and gene expression information, which opens the door for understanding of the molecular mechanism of olfactory learning behavior in honeybees.

Differentiation of memory processing stages and effect of demographic variables with alternative scoring approaches to the Rey auditory verbal learning test

ABSTRACT Background The Rey Auditory Verbal Learning Test (RAVLT) is the third most popular verbal memory test and the tenth most frequently used neuropsychological test. The original scoring system of RAVLT does not differentiate stages of memory processing, but a recently developed composite scoring system has this potential. The objectives were to compare the two systems in terms of their capacity to differentiate the stages of memory processing and to study the effect of demographic variables on the learning trials (T) of the Turkish form of RAVLT (T-RAVLT). Method The sample consisted of 600 Caucasian Turkic adults, who were categorized into three levels of age, three levels of education, and two levels of gender. Individual administration of T-RAVLT was performed using the standard procedures of RAVLT. Results The components in the exploratory factor analysis (EFA) and latent variables in the confirmatory factor analysis (CFA) of the original scores were consistent with sequentially ordered T-RAVLT stages. Demographic variables (age, education, and gender) affected performances in all of the learning trials. The composite scores revealed retrieval and retention as separate components, but these scores could not be predicted from the relevant T-RAVLT scores. Conclusions Findings recommend a combined utilization of the two scoring systems: The original system to provide scores on the performance at each stage of T-RAVLT and the combined system to provide separate scores on learning, retention, and retrieval, the three stages of memory processing. A selective effect of demographic variables on T1 was not observed, indicating a need for cross-cultural studies that are meticulously controlled for age and education.

Emotion words link faces to emotional scenarios in early childhood.

Recent theories have suggested that emotion words may facilitate the development of emotion concepts. The present study investigates whether emotion words affect children's performance on an emotion category learning task. Across two experiments, 72 three-year-old children (49 female) were asked to identify which emotional face best matched particular emotional scenarios during nine pretest and nine posttest trials. The scenarios in the present studies aligned with emotions typically learned among older age groups (annoyed, disgusted, and nervous). Between pretest and posttest, children participated in training in which a facial configuration (annoyed, disgusted, or nervous) was paired with an associated scenario while they heard the emotion labeled explicitly or heard irrelevant information (Experiment 1) or heard a broad emotion label versus irrelevant information (Experiment 2). Aside from the labels presented, all other information was kept the same across conditions, including the specific faces and scenarios heard during learning trials. In Experiment 1, children's emotion understanding increased more from pretest to posttest in the explicit label versus irrelevant condition, t(34) = 2.26, p = .030, d = .75, but in Experiment 2 the broad emotion labels did not provide an advantage over irrelevant information, t(34) = .72, p = .474, d = .24. These results suggest that emotion labels may be particularly helpful for young children learning about unfamiliar emotions, because specific labels may help children to aggregate disparate emotional information into meaningful categories. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Clinical pharmacology: Current innovations and future challenges.

Clinical pharmacology is the study of drugs in humans, from first-in-human studies to randomized controlled trials (RCTs) and benefit-risk ratio assessment in large populations. The objective of this review is to present the recent innovations that may revolutionize the development of drugs in the future. On behalf of the French Society of Pharmacology and Therapeutics, we provide recommendations to address those future challenges in clinical pharmacology. Whatever the future will be, robust preliminary data on drug mechanism of action and rigorous study design will remain crucial prior to the start of pharmacological studies in human. At the present time, RCTs remain the gold standard to evaluate the efficacy of human drugs, although alternative designs (pragmatic trials, platform trials, etc.) are emerging. Innovations in healthy volunteers' studies and the contribution of new technologies such as artificial intelligence, machine learning, and internet-based trials have the potential to improve drug development. In the field of precision medicine, new disease phenotypes and endotypes will probably help to identify new pharmacological targets, responders to therapies, and patients at risk for drug adverse events. In such a moving landscape, the development of translational research through academic and private partnership, transparent sharing of clinical trial data and enhanced interactions between drug experts, patients, and the general public are priority areas for action.

Brain Stimulation Using Responsive Neurostimulation Improves Verbal Memory: A Crossover Case-Control Study.

The effects of brain stimulation on memory formation in humans have shown conflicting results in previous studies. We hypothesized that direct cortical stimulation using an implanted responsive neurostimulation (RNS) system will improve memory. To evaluate whether direct cortical stimulation using RNS improves memory as measured with recall scores of a list-learning task. During outpatient visits, a list-learning task (Hopkins Verbal Learning Test-Revised) was administered to 17 patients with RNS implants. Patients were read a list of 12 semantically related words and asked to recall the list after 3 different learning trials. True or sham stimulations were performed for every third word presented for immediate recall. Most patients had frontotemporal network stimulation-one patient each had insular and parietal stimulations. After a 20-min delay, they were asked to recall the list again, first freely and then through a "yes/no" recognition paradigm. A crossover design was used in which half the patients had true stimulation during the initial visit and half had sham stimulation-followed by crossover to the other group at the next visit. The Hopkins Verbal Learning Test-Revised delayed recall raw score was higher for the stimulation condition compared with the nonstimulation condition (paired t -test, P = .04, effect size d = 0.627). Verbal memory improves by direct cortical stimulation during a list-learning task. The RNS system can be effectively used in memory research using direct cortical stimulation. This study has implications in the development of neurostimulation devices for cognitive enhancement in conditions such as epilepsy, dementia, and traumatic brain injury.

Comparing Coding Viewing and Recording Methods to Quantify Embedded Instruction Learning Trials

The purpose of this study was to examine the comparability of counts of embedded instruction learning trials when different methods of viewing and recording direct behavioral observations were used. In 13 classrooms, while videotaping embedded instruction implementation for a larger randomized controlled efficacy trial was occurring, teachers’ implementation of trials was coded in situ using pencil-and-paper methods. Videos were later coded using computer-assisted methods. Dependent-samples t tests, Pearson product-moment correlation coefficients, and additional score agreement calculations were conducted. Statistically significant differences were found in the estimates of trial frequency. Correlational analyses showed positive and strong relationships between the coding methods. Coding agreement was higher across the entire observation versus during 10-min continuous event blocks. In situ coding took significantly less time than video coding. Results provide empirical evidence for the advantages and disadvantages of common viewing and recording methods for quantifying behavior as part of systematic observation systems.

Rate of forgetting is independent of initial degree of learning

It is commonly assumed that the rate of forgetting depends on initial degree of learning. Hence, comparison of forgetting across groups is usually carried out equating initial performance. However, these matching procedures add confounding variables. In four experiments, following Slamecka and McElree (1983, Exp 3), we challenge this assumption through manipulating initial acquisition by varying the number of presentations of the material and studying the effect on rate of subsequent forgetting. A set of 36 sentences was presented either visually or auditorily. Different participants were exposed to the material two, four or six times. Forgetting was measured by means of a cued recall test at three time-intervals (30 s, 1 day and 1 week in experiments 1 and 2; 30 s, 1 day, and 3 days in experiments 3 and 4). A different subset of 12 sentences was tested at each delay. The outcome of these experiments showed that the initial acquisition depends on number of learning trials. However, the rate of forgetting proved to be independent of initial acquisition. This pattern remains constant across modalities of presentation and of the number of learning trials. The conclusion is that forgetting does not depend on initial acquisition.

The Contributions of Immediate Retrieval and Spaced Retrieval to Word Learning in Preschoolers with Developmental Language Disorder.

Background and Aims Children with developmental language disorder (DLD) benefit from word learning procedures that include a mix of immediate retrieval and spaced retrieval trials. In this study, we examine the relative contribution of these two types of retrieval. Methods We examine data from Haebig et al. (2019) in their study that compared an immediate retrieval condition and a condition of spaced retrieval that also included immediate retrieval trials. Participants were 4- and 5-year old children with DLD and same-age peers with typical language development. Each child learned novel (made-up) words referring to unusual plants and animals in both conditions. We examined the phonetic accuracy of the novel words used during the final learning trial and during recall tests 5 min and 1 week after learning. Results On the final learning trial, the children were more phonetically accurate in using the novel words learned in the immediate retrieval condition. However, recall tests after the learning trials revealed a decrease in accuracy, especially for the children with DLD. After one week, accuracy was much lower for words in the immediate retrieval condition than for words in the mixed spaced-plus-immediate retrieval condition. For words learned in the mixed spaced-plus-immediate retrieval condition, accuracy was very stable across time for both groups. Conclusions Immediate retrieval boosts the phonetic accuracy of new words in the short term but spaced retrieval promotes stability and increases the likelihood that short-term gains are maintained. Implications: When novel word learning is assessed at the level of phonetic accuracy, children with DLD can show declines over time not characteristic of children with typical language development. Spaced retrieval procedures augmented by immediate retrieval opportunities during learning appear to prevent such declines, leading to longer-lasting gains.

Вплив конструкторсько-технологічних чинників на довговічність вставного твердосплавного породоруйнівного оснащення шарошок тришарошкових бурових доліт

Aim. In the study learning trial was made to make a mathematical model of the assembling process in connections " tungsten carbide insert cutter - cone", while the methods of mathematical statistics were applied. This makes it possible to determine the parameters of the distribution of the closing link. Accordingly, the tension is determined by samples of constituent links. For this purpose, the amount of tension was investigated. Tension affects the change in stress, which characterizes the accuracy of the assembly on the strength of the connection " tungsten carbide insert cutter - cone ". Depending on the magnitude of the insert pressing force, it is customary to estimate the tension in the connection. Method. The analysis of tungsten carbide insert cutter and holes in the layers of bit established that the size errors of the component links of dimensional chains are distributed according to laws that they are similar to the normal law of the distribution of random variables. The test was carried out according to the criteria of Pearson and Kolmogorov Results. The increase in pressing force with an increase in tension is due to an increase in elastic deformation both in the cemented layer and in the core layers of the rolling-cutter row. The extreme nature of the dependence of the pressing force on the amount of tension for the connection " tungsten carbide insert cutter - cone " has been established. This dependence, as a characteristic of the strength in the connection, can be used to design technological pressing operations for roller cone bits steels with different strength indicators. Scientific novelty. a mathematical model of the assembling process of connections " tungsten carbide insert cutter - cone " was made. It makes it possible to determine the parameters of the distribution of the closing link - tension, based on the samples of the component links. The established dependencies make it possible to reasonably and most accurately approach the formation of selective groups of teeth and the marking of holes for them. Practical significance. The appointment of tensions, the value of which exceeds the value of the extreme point, causes the occurrence of unfavorable plastic deformation or destruction of the layers of the shell (which are conjugated along the height of the shank of the insert cutter). They also result to the occurrence of irrational stresses in the body of the tungsten carbide insert cutter. It was established that the tension values have a greater influence on the force of pressing carbide teeth into the holes of roller cone bits steel 9310H (USA), when its hardness value is Rockwell hardness 59-60 compared to Rockwell hardness 48-50. Within the limits of the studied tension values, this dependence is linear.