4,489 research outputs found

    Verbal Learning and Memory After Cochlear Implantation in Postlingually Deaf Adults: Some New Findings with the CVLT-II

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    OBJECTIVES: Despite the importance of verbal learning and memory in speech and language processing, this domain of cognitive functioning has been virtually ignored in clinical studies of hearing loss and cochlear implants in both adults and children. In this article, we report the results of two studies that used a newly developed visually based version of the California Verbal Learning Test-Second Edition (CVLT-II), a well-known normed neuropsychological measure of verbal learning and memory. DESIGN: The first study established the validity and feasibility of a computer-controlled visual version of the CVLT-II, which eliminates the effects of audibility of spoken stimuli, in groups of young normal-hearing and older normal-hearing (ONH) adults. A second study was then carried out using the visual CVLT-II format with a group of older postlingually deaf experienced cochlear implant (ECI) users (N = 25) and a group of ONH controls (N = 25) who were matched to ECI users for age, socioeconomic status, and nonverbal IQ. In addition to the visual CVLT-II, subjects provided data on demographics, hearing history, nonverbal IQ, reading fluency, vocabulary, and short-term memory span for visually presented digits. ECI participants were also tested for speech recognition in quiet. RESULTS: The ECI and ONH groups did not differ on most measures of verbal learning and memory obtained with the visual CVLT-II, but deficits were identified in ECI participants that were related to recency recall, the buildup of proactive interference, and retrieval-induced forgetting. Within the ECI group, nonverbal fluid IQ, reading fluency, and resistance to the buildup of proactive interference from the CVLT-II consistently predicted better speech recognition outcomes. CONCLUSIONS: Results from this study suggest that several underlying foundational neurocognitive abilities are related to core speech perception outcomes after implantation in older adults. Implications of these findings for explaining individual differences and variability and predicting speech recognition outcomes after implantation are discussed

    Logistic Knowledge Tracing: A Constrained Framework for Learner Modeling

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    Adaptive learning technology solutions often use a learner model to trace learning and make pedagogical decisions. The present research introduces a formalized methodology for specifying learner models, Logistic Knowledge Tracing (LKT), that consolidates many extant learner modeling methods. The strength of LKT is the specification of a symbolic notation system for alternative logistic regression models that is powerful enough to specify many extant models in the literature and many new models. To demonstrate the generality of LKT, we fit 12 models, some variants of well-known models and some newly devised, to 6 learning technology datasets. The results indicated that no single learner model was best in all cases, further justifying a broad approach that considers multiple learner model features and the learning context. The models presented here avoid student-level fixed parameters to increase generalizability. We also introduce features to stand in for these intercepts. We argue that to be maximally applicable, a learner model needs to adapt to student differences, rather than needing to be pre-parameterized with the level of each student's ability

    Novel hybrid extraction systems for fetal heart rate variability monitoring based on non-invasive fetal electrocardiogram

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    This study focuses on the design, implementation and subsequent verification of a new type of hybrid extraction system for noninvasive fetal electrocardiogram (NI-fECG) processing. The system designed combines the advantages of individual adaptive and non-adaptive algorithms. The pilot study reviews two innovative hybrid systems called ICA-ANFIS-WT and ICA-RLS-WT. This is a combination of independent component analysis (ICA), adaptive neuro-fuzzy inference system (ANFIS) algorithm or recursive least squares (RLS) algorithm and wavelet transform (WT) algorithm. The study was conducted on clinical practice data (extended ADFECGDB database and Physionet Challenge 2013 database) from the perspective of non-invasive fetal heart rate variability monitoring based on the determination of the overall probability of correct detection (ACC), sensitivity (SE), positive predictive value (PPV) and harmonic mean between SE and PPV (F1). System functionality was verified against a relevant reference obtained by an invasive way using a scalp electrode (ADFECGDB database), or relevant reference obtained by annotations (Physionet Challenge 2013 database). The study showed that ICA-RLS-WT hybrid system achieve better results than ICA-ANFIS-WT. During experiment on ADFECGDB database, the ICA-RLS-WT hybrid system reached ACC > 80 % on 9 recordings out of 12 and the ICA-ANFIS-WT hybrid system reached ACC > 80 % only on 6 recordings out of 12. During experiment on Physionet Challenge 2013 database the ICA-RLS-WT hybrid system reached ACC > 80 % on 13 recordings out of 25 and the ICA-ANFIS-WT hybrid system reached ACC > 80 % only on 7 recordings out of 25. Both hybrid systems achieve provably better results than the individual algorithms tested in previous studies.Web of Science713178413175

    Cognitive finance: Behavioural strategies of spending, saving, and investing.

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    Research in economics is increasingly open to empirical results. The advances in behavioural approaches are expanded here by applying cognitive methods to financial questions. The field of "cognitive finance" is approached by the exploration of decision strategies in the financial settings of spending, saving, and investing. Individual strategies in these different domains are searched for and elaborated to derive explanations for observed irregularities in financial decision making. Strong context-dependency and adaptive learning form the basis for this cognition-based approach to finance. Experiments, ratings, and real world data analysis are carried out in specific financial settings, combining different research methods to improve the understanding of natural financial behaviour. People use various strategies in the domains of spending, saving, and investing. Specific spending profiles can be elaborated for a better understanding of individual spending differences. It was found that people differ along four dimensions of spending, which can be labelled: General Leisure, Regular Maintenance, Risk Orientation, and Future Orientation. Saving behaviour is strongly dependent on how people mentally structure their finance and on their self-control attitude towards decision space restrictions, environmental cues, and contingency structures. Investment strategies depend on how companies, in which investments are placed, are evaluated on factors such as Honesty, Prestige, Innovation, and Power. Further on, different information integration strategies can be learned in decision situations with direct feedback. The mapping of cognitive processes in financial decision making is discussed and adaptive learning mechanisms are proposed for the observed behavioural differences. The construal of a "financial personality" is proposed in accordance with other dimensions of personality measures, to better acknowledge and predict variations in financial behaviour. This perspective enriches economic theories and provides a useful ground for improving individual financial services

    Cognitive Decay And Memory Recall During Long Duration Spaceflight

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    This dissertation aims to advance the efficacy of Long-Duration Space Flight (LDSF) pre-flight and in-flight training programs, acknowledging existing knowledge gaps in NASA\u27s methodologies. The research\u27s objective is to optimize the cognitive workload of LDSF crew members, enhance their neurocognitive functionality, and provide more meaningful work experiences, particularly for Mars missions.The study addresses identified shortcomings in current training and learning strategies and simulation-based training systems, focusing on areas requiring quantitative measures for astronaut proficiency and training effectiveness assessment. The project centers on understanding cognitive decay and memory loss under LDSF-related stressors, seeking to establish when such cognitive decline exceeds acceptable performance levels throughout mission phases. The research acknowledges the limitations of creating a near-orbit environment due to resource constraints and the need to develop engaging tasks for test subjects. Nevertheless, it underscores the potential impact on future space mission training and other high-risk professions. The study further explores astronaut training complexities, the challenges encountered in LDSF missions, and the cognitive processes involved in such demanding environments. The research employs various cognitive and memory testing events, integrating neuroimaging techniques to understand cognition\u27s neural mechanisms and memory. It also explores Rasmussen\u27s S-R-K behaviors and Brain Network Theory’s (BNT) potential for measuring forgetting, cognition, and predicting training needs. The multidisciplinary approach of the study reinforces the importance of integrating insights from cognitive psychology, behavior analysis, and brain connectivity research. Research experiments were conducted at the University of North Dakota\u27s Integrated Lunar Mars Analog Habitat (ILMAH), gathering data from selected subjects via cognitive neuroscience tools and Electroencephalography (EEG) recordings to evaluate neurocognitive performance. The data analysis aimed to assess brain network activations during mentally demanding activities and compare EEG power spectra across various frequencies, latencies, and scalp locations. Despite facing certain challenges, including inadequacies of the current adapter boards leading to analysis failure, the study provides crucial lessons for future research endeavors. It highlights the need for swift adaptation, continual process refinement, and innovative solutions, like the redesign of adapter boards for high radio frequency noise environments, for the collection of high-quality EEG data. In conclusion, while the research did not reveal statistically significant differences between the experimental and control groups, it furnished valuable insights and underscored the need to optimize astronaut performance, well-being, and mission success. The study contributes to the ongoing evolution of training methodologies, with implications for future space exploration endeavors

    Developmental, morphological, and behavioural plasticity in the reproductive strategies of stink bugs and their egg parasitoids

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    L’environnement façonne la physiologie, la morphologie et le comportement des organismes par l’entremise de processus Ă©cologiques et Ă©volutifs complexes et multidimensionnels. Le succĂšs reproducteur des animaux est dĂ©terminĂ© par la valeur adaptative d’un phĂ©notype dans un environnement en modification constante selon une Ă©chelle temporelle d’une Ă  plusieurs gĂ©nĂ©rations. De plus, les phĂ©notypes sont façonnĂ©s par l’environnement, ce qui entraine des modifications adaptatives des stratĂ©gies de reproduction tout en imposant des contraintes. Dans cette thĂšse, considĂ©rant des punaises et leurs parasitoĂŻdes comme organismes modĂšles, j’ai investiguĂ© comment plusieurs types de plasticitĂ© peuvent interagir pour influencer la valeur adaptative, et comment la plasticitĂ© des stratĂ©gies de reproduction rĂ©pond Ă  plusieurs composantes des changements environnementaux (qualitĂ© de l’hĂŽte, radiation ultraviolette, tempĂ©rature, invasion biologique). PremiĂšrement, j’ai comparĂ© la rĂ©ponse comportementale et de traits d’histoire de vie Ă  la variation de taille corporelle chez le parasitoĂŻde Telenomus podisi Ashmead (Hymenoptera : Platygastridae), dĂ©montrant que les normes de rĂ©action des comportements Ă©taient plus souvent positives que celles des traits d’histoires de vie. Ensuite, j’ai dĂ©montrĂ© que la punaise prĂ©datrice Podisus maculiventris Say (Hemiptera : Pentatomidae) peut contrĂŽler la couleur de ses Ɠufs, et que la pigmentation des Ɠufs protĂšge les embryons du rayonnement ultraviolet; une composante d’une stratĂ©gie complexe de ponte qui a Ă©voluĂ©e en rĂ©ponse Ă  une multitude de facteurs environnementaux. Puis, j’ai testĂ© comment le stress thermique affectait la dynamique de la mĂ©moire du parasitoĂŻde Trissolcus basalis (Wollaston) (Hymenoptera : Platygastridae) lors de l’apprentissage de la fiabilitĂ© des traces chimiques laissĂ©es par son hĂŽte. Ces expĂ©riences ont rĂ©vĂ©lĂ© que des tempĂ©ratures hautes et basses prĂ©venaient l’oubli, affectant ainsi l’allocation du temps passĂ© par les parasitoĂŻdes dans des agrĂ©gats d’hĂŽtes contenant des traces chimiques. J’ai aussi dĂ©veloppĂ© un cadre thĂ©orique gĂ©nĂ©ral pour classifier les effets de la tempĂ©rature sur l’ensemble des aspects comportementaux des ectothermes, distinguant les contraintes des adaptations. Finalement, j’ai testĂ© l’habiletĂ© d’un parasitoĂŻde indigĂšne (T. podisi) Ă  exploiter les Ɠufs d’un nouveau ravageur invasif en agriculture, Halyomorpha halys StĂ„l (Hemiptera : Pentatomidae). Les rĂ©sultats ont montrĂ© que T. podisi attaque les Ɠufs de H. halys, mais qu’il ne peut s’y dĂ©velopper, indiquant que le ravageur invasif s’avĂšre un « piĂšge Ă©volutif » pour ce parasitoĂŻde. Cela pourrait indirectement bĂ©nĂ©ficier aux espĂšces indigĂšnes de punaises en agissant comme un puits Ă©cologique de ressources (Ɠufs) et de temps pour le parasitoĂŻde. Ces rĂ©sultats ont des implications importantes sur la rĂ©ponse des insectes, incluant ceux impliquĂ©s dans les programmes de lutte biologique, face aux changements environnementaux.The environment shapes the physiology, morphology, and behaviour of organisms through complex, multidimensional ecological and evolutionary processes. The reproductive success of individual animals is determined by how well their phenotype is suited to an environment that is constantly changing over single and multi-generational time scales. At the same time, phenotypes are shaped by the environment, which triggers adaptive modifications of animal reproductive strategies while also imposing important constraints. In this thesis, using stink bugs and their parasitoids as model organisms, I considered how several types of plasticity can interact to influence biological fitness, and how plasticity in reproductive strategies responds to several important components of environmental change (host quality, ultraviolet radiation, temperature, biological invasions). Firstly, I compared the response of behavioural and life history traits to body size variation in the parasitoid Telenomus podisi Ashmead (Hymenoptera: Platygastridae), finding that reaction norms of behavioural traits more often had positive slopes than life history traits. Next, I found that the predatory stink bug Podisus maculiventris Say (Hemiptera: Pentatomidae) can selectively control the colouration of its eggs. Egg pigmentation in this species protects embryos against ultraviolet radiation as part of a complex oviposition strategy that evolved in response to a suite of environmental factors. Then, I tested how thermal stress affects the memory dynamics of the parasitoid Trissolcus basalis (Wollaston) (Hymenoptera: Platygastridae) learning the reliability of chemical traces left by its host. These experiments revealed that both high and low stressful temperatures prevented forgetting, affecting the time allocation of parasitoids on patches of host chemical traces. I also developed a general framework to classify temperature’s effects on all aspects of ectotherm behaviour, distinguishing constraints from adaptive behavioural adjustments. Finally, I tested the ability of an indigenous parasitoid (T. podisi) to attack the eggs of a new invasive pest of agriculture, Halyomorpha halys StĂ„l (Hemiptera: Pentatomidae). The results showed that T. podisi attacks the eggs of H. halys but cannot develop, demonstrating that the invasive pest is an “evolutionary trap” for indigenous parasitoids, which could indirectly benefit native stink bug species by acting as an egg and time sink for the parasitoid. These findings have important implications for how insects, including those involved in biological control programs, respond to environmental change

    Thermal stress affects patch time allocation by preventing forgetting in a parasitoid wasp

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    Learning and memory allow animals to adjust their foraging strategies through experience. Despite the known impact of temperature on many aspects of the behavioral ecology of animals, memory retention in the face of realistic thermal stress has seldom been assessed. In the laboratory, we studied the behavioral expression of an egg parasitoid's (Trissolcus basalis) memory when exposed to thermal stress that could be encountered in nature. We hypothesized that thermal stress would disrupt memory consolidation and/or modify the optimality of memory retention, thus affecting patch time allocation strategies. Memory consolidation was resilient to 1h of thermal stress following an unrewarded experience (learning) on a patch of host-associated infochemicals. Neither high (40 °C) or low (10 °C) thermal stress changed the intensity of the experienced wasps' behavioral response relative to those held at a moderate temperature (25 °C). Next, we investigated how temperature stress could affect the parasitoids' memory retention ("forgetting"). When kept at a constant moderate temperature after learning, residence times of wasps retested on host cues increased relative to controls (naive wasps) over a period of 4 days as they presumably "forgot." However, both hot and cool daily temperature cycles prevented forgetting; the residence times of retested experienced wasps in these treatments did not change relative to controls over time. We discuss to what extent this may be an adaptive response by the parasitoids versus a physiological constraint imposed by temperature. Our findings contribute to an understanding of the impact of thermal stress on foraging strategies that involve learning and memory
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