827 resultados para cognitive function
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The current study investigated the exculpatory value of alibi evidence when presented together with various types of incriminating evidence. Previous research has reported that alibi evidence could weaken the effects of DNA evidence and eyewitness identification. The present study assessed the effectiveness of alibi evidence in counteracting defendant's confession (experiment 1) and eyewitness evidence (experiment 2). In experiment 1, three levels of alibi evidence (none, weak, strong) were combined with three levels of confession evidence (voluntary, elicited under low pressure, elicited under high pressure). Results indicated significant main effects of confession and alibi and an alibi by confession interaction. Of participants exposed to high-pressure confession, those in the strong alibi condition rendered lower guilt estimates than those in the no alibi condition. In experiment 2, three levels of alibi were combined with two levels of eyewitness evidence (bad view, good view). A main effect of alibi was obtained, but no interaction between alibi and eyewitness evidence. ^ An explanation of this pattern is based in part on the Story Model (Pennington & Hastie, 1992) and a novel “culpability threshold” model of juror decision-making. The Story Model suggests that jurors generate verdict stories (interpretations of events consistent with a guilty or not guilty verdict) based on trial evidence. If the evidence in favor of guilt exceeds jurors' threshold for perceiving culpability, jurors will fail to properly consider exonerating evidence. However, when the strength of incriminating evidence does not exceed the jurors' threshold, they are likely to give appropriate consideration to exculpatory evidence in their decisions. ^ Presentation of a reliable confession in Experiment 1 exceeded jurors' culpability threshold and rendered alibi largely irrelevant. In contrast, presentation of a high-pressure confession failed to exceed jurors' culpability threshold, so jurors turned to alibi evidence in their decisions. Similarly, in the second experiment, eyewitness evidence (in general) was not strong enough to surpass the culpability threshold, and thus jurors incorporated alibi evidence in their decisions. A third study is planned to further test this “culpability threshold” model, further explore various types of alibi evidence, and clarify when exculpatory evidence will sufficiently weaken the prosecution's “story.” ^
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Memory deficits and executive dysfunction are highly prevalent among HIV-infected adults. These conditions can affect their quality of life, antiretroviral adherence, and HIV risk behaviors. Several factors have been suggested including the role of genetics in relation to HIV disease progression. This dissertation aimed to determine whether genetic differences in HIV-infected individuals were correlated with impaired memory, cognitive flexibility and executive function and whether cognitive decline moderated alcohol use and sexual transmission risk behaviors among HIV-infected alcohol abusers participating in an NIH-funded clinical trial comparing the efficacy of the adapted Holistic Health Recovery Program (HHRP-A) intervention to a Health Promotion Control (HPC) condition in reducing risk behaviors. ^ A total of 267 individuals were genotyped for polymorphisms in the dopamine and serotonin gene systems. Results yielded significant associations for TPH2, GALM, DRD2 and DRD4 genetic variants with impaired executive function, cognitive flexibility and memory. SNPs TPH2 rs4570625 and DRD2 rs6277 showed a risk association with executive function (odds ratio = 2.5, p = .02; 3.6, p = .001). GALM rs6741892 was associated with impaired memory (odds ratio = 1.9, p = .006). At the six-month follow-up, HHRP-A participants were less likely to report trading sex for food, drugs and money (20.0%) and unprotected insertive or receptive oral (11.6%) or vaginal and/or anal sex (3.2%) than HPC participants (49.4%, p^
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This work was supported by a grant from the UK Economic and Social Research Council (ES/L010437/1).
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Duchenne muscular dystrophy (DMD) is an X chromosome-linked disease characterized by progressive physical disability, immobility, and premature death in affected boys. Underlying the devastating symptoms of DMD is the loss of dystrophin, a structural protein that connects the extracellular matrix to the cell cytoskeleton and provides protection against contraction-induced damage in muscle cells, leading to chronic peripheral inflammation. However, dystrophin is also expressed in neurons within specific brain regions, including the hippocampus, a structure associated with learning and memory formation. Linked to this, a subset of boys with DMD exhibit nonprogressing cognitive dysfunction, with deficits in verbal, short-term, and working memory. Furthermore, in the genetically comparable dystrophin-deficient mdx mouse model of DMD, some, but not all, types of learning and memory are deficient, and specific deficits in synaptogenesis and channel clustering at synapses has been noted. Little consideration has been devoted to the cognitive deficits associated with DMD compared with the research conducted into the peripheral effects of dystrophin deficiency. Therefore, this review focuses on what is known about the role of full-length dystrophin (Dp427) in hippocampal neurons. The importance of dystrophin in learning and memory is assessed, and the potential importance that inflammatory mediators, which are chronically elevated in dystrophinopathies, may have on hippocampal function is also evaluated.
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Memory deficits and executive dysfunction are highly prevalent among HIV-infected adults. These conditions can affect their quality of life, antiretroviral adherence, and HIV risk behaviors. Several factors have been suggested including the role of genetics in relation to HIV disease progression. This dissertation aimed to determine whether genetic differences in HIV-infected individuals were correlated with impaired memory, cognitive flexibility and executive function and whether cognitive decline moderated alcohol use and sexual transmission risk behaviors among HIV-infected alcohol abusers participating in an NIH-funded clinical trial comparing the efficacy of the adapted Holistic Health Recovery Program (HHRP-A) intervention to a Health Promotion Control (HPC) condition in reducing risk behaviors. A total of 267 individuals were genotyped for polymorphisms in the dopamine and serotonin gene systems. Results yielded significant associations for TPH2, GALM, DRD2 and DRD4 genetic variants with impaired executive function, cognitive flexibility and memory. SNPs TPH2 rs4570625 and DRD2 rs6277 showed a risk association with executive function (odds ratio = 2.5, p = .02; 3.6, p = .001). GALM rs6741892 was associated with impaired memory (odds ratio = 1.9, p = .006). At the six-month follow-up, HHRP-A participants were less likely to report trading sex for food, drugs and money (20.0%) and unprotected insertive or receptive oral (11.6%) or vaginal and/or anal sex (3.2%) than HPC participants (49.4%, p
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Cognitive radio (CR) is fast emerging as a promising technology that can meet the machine-to machine (M2M) communication requirements for spectrum utilization and power control for large number of machines/devices expected to be connected to the Internet-of Things (IoT). Power control in CR as a secondary user can been modelled as a non-cooperative game cost function to quantify and reduce its effects of interference while occupying the same spectrum as primary user without adversely affecting the required quality of service (QoS) in the network. In this paper a power loss exponent that factors in diverse operating environments for IoT is employed in the non-cooperative game cost function to quantify the required power of transmission in the network. The approach would enable various CRs to transmit with lesser power thereby saving battery consumption or increasing the number of secondary users thereby optimizing the network resources efficiently.
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Nervous system disorders are associated with cognitive and motor deficits, and are responsible for the highest disability rates and global burden of disease. Their recovery paths are vulnerable and dependent on the effective combination of plastic brain tissue properties, with complex, lengthy and expensive neurorehabilitation programs. This work explores two lines of research, envisioning sustainable solutions to improve treatment of cognitive and motor deficits. Both projects were developed in parallel and shared a new sensible approach, where low-cost technologies were integrated with common clinical operative procedures. The aim was to achieve more intensive treatments under specialized monitoring, improve clinical decision-making and increase access to healthcare. The first project (articles I – III) concerned the development and evaluation of a web-based cognitive training platform (COGWEB), suitable for intensive use, either at home or at institutions, and across a wide spectrum of ages and diseases that impair cognitive functioning. It was tested for usability in a memory clinic setting and implemented in a collaborative network, comprising 41 centers and 60 professionals. An adherence and intensity study revealed a compliance of 82.8% at six months and an average of six hours/week of continued online cognitive training activities. The second project (articles IV – VI) was designed to create and validate an intelligent rehabilitation device to administer proprioceptive stimuli on the hemiparetic side of stroke patients while performing ambulatory movement characterization (SWORD). Targeted vibratory stimulation was found to be well tolerated and an automatic motor characterization system retrieved results comparable to the first items of the Wolf Motor Function Test. The global system was tested in a randomized placebo controlled trial to assess its impact on a common motor rehabilitation task in a relevant clinical environment (early post-stroke). The number of correct movements on a hand-to-mouth task was increased by an average of 7.2/minute while the probability to perform an error decreased from 1:3 to 1:9. Neurorehabilitation and neuroplasticity are shifting to more neuroscience driven approaches. Simultaneously, their final utility for patients and society is largely dependent on the development of more effective technologies that facilitate the dissemination of knowledge produced during the process. The results attained through this work represent a step forward in that direction. Their impact on the quality of rehabilitation services and public health is discussed according to clinical, technological and organizational perspectives. Such a process of thinking and oriented speculation has led to the debate of subsequent hypotheses, already being explored in novel research paths.
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Cognitive radio (CR) was developed for utilizing the spectrum bands efficiently. Spectrum sensing and awareness represent main tasks of a CR, providing the possibility of exploiting the unused bands. In this thesis, we investigate the detection and classification of Long Term Evolution (LTE) single carrier-frequency division multiple access (SC-FDMA) signals, which are used in uplink LTE, with applications to cognitive radio. We explore the second-order cyclostationarity of the LTE SC-FDMA signals, and apply results obtained for the cyclic autocorrelation function to signal detection and classification (in other words, to spectrum sensing and awareness). The proposed detection and classification algorithms provide a very good performance under various channel conditions, with a short observation time and at low signal-to-noise ratios, with reduced complexity. The validity of the proposed algorithms is verified using signals generated and acquired by laboratory instrumentation, and the experimental results show a good match with computer simulation results.
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As with any cognitive ability, attention is vulnerable to dysfunction. The most common attentional problem is attention deficit hyperactivity disorder (ADHD). This brief overview will highlight the symptoms and deficits associated with ADHD, its prevalence in today’s society, the association between executive function impairment and ADHD using Barkley’s (1997) work, and the personal and societal effects of the disorder.
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Socioeconomic status (SES) influences language and cognitive development, with discrepancies particularly noticeable in vocabulary development. This study examines how SES-related differences impact the development of syntactic processing, cognitive inhibition, and word learning. 38 4-5-year-olds from higher- and lower-SES backgrounds completed a word-learning task, in which novel words were embedded in active and passive sentences. Critically, unlike the active sentences, all passive sentences required a syntactic revision. Measures of cognitive inhibition were obtained through a modified Stroop task. Results indicate that lower-SES participants had more difficulty using inhibitory functions to resolve conflict compared to their higher-SES counterparts. However, SES did not impact language processing, as the language outcomes were similar across SES background. Additionally, stronger inhibitory processes were related to better language outcomes in the passive sentence condition. These results suggest that cognitive inhibition impact language processing, but this function may vary across children from different SES backgrounds
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The effects of individual teacher expectations have been the subject of intensive research. Results indicate that teachers use their expectations to adapt their interactions with their students to some degree (as summarized in a review by Jussim & Harber, 2005). This can in turn lead to expectancy-confirming student developments. While there are studies on the Pygmalion effect on individual students, there is only little research on teacher judgements of whole classes and schools. Our study aims to extend the perspective of teacher judgements at the collective level to stereotypes within the context of school tracking. The content and structure of teachers’ school track stereotypes are investigated as well as the question of whether these stereotypical judgements are related to teachers’ perception of obstacles to their teaching and their teaching self-efficacy beliefs. Cross-sectional data on 341 teachers at two different school types from the Panel Study at the Research School „Education and Capabilities“ in North Rhine-Westphalia (PARS) (see Bos et al., 2016) were used for two purposes: First, the structure of teachers’ stereotypes was identified via an exploratory factor analysis. Second, in follow-up regression analyses, the stereotype dimensions extracted were used to predict teachers’ perceptions of obstacles to their classroom work and their individual and collective teacher self-efficacy beliefs. Results showed that – after controlling for the average cognitive abilities and the average cultural capital of the students – teacher stereotypes were indeed related to perceived obstacles concerning their classroom work and their self-efficacy beliefs. After a discussion of the strengths and limitations of the present research, the article closes with a short proposal of a future research framework for collective Pygmalion effects. (DIPF/Orig.)
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Spiking neural networks - networks that encode information in the timing of spikes - are arising as a new approach in the artificial neural networks paradigm, emergent from cognitive science. One of these new models is the pulsed neural network with radial basis function, a network able to store information in the axonal propagation delay of neurons. Learning algorithms have been proposed to this model looking for mapping input pulses into output pulses. Recently, a new method was proposed to encode constant data into a temporal sequence of spikes, stimulating deeper studies in order to establish abilities and frontiers of this new approach. However, a well known problem of this kind of network is the high number of free parameters - more that 15 - to be properly configured or tuned in order to allow network convergence. This work presents for the first time a new learning function for this network training that allow the automatic configuration of one of the key network parameters: the synaptic weight decreasing factor.
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Discourses evoking an antibiotic apocalypse and a war on superbugs are emerging just at a time when so-called "catastrophe discourses" are undergoing critical and reflexive scrutiny in the context of global warming and climate change. This article combines insights from social science research into climate change discourses with applied metaphor research based on recent advances in cognitive linguistics, especially with relation to "discourse metaphors." It traces the emergence of a new apocalyptic discourse in microbiology and health care, examines its rhetorical and political function and discusses its advantages and disadvantages. It contains a reply by the author of the central discourse metaphor, "the post-antibiotic apocalypse," examined in the article.
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Background: Preclinical studies have identified certain probiotics as psychobiotics a live microorganisms with a potential mental health benefit. Lactobacillus rhamnosus (JB-1) has been shown to reduce stress-related behaviour, corticosterone release and alter central expression of GABA receptors in an anxious mouse strain. However, it is unclear if this single putative psychobiotic strain has psychotropic activity in humans. Consequently, we aimed to examine if these promising preclinical findings could be translated to healthy human volunteers. Objectives: To determine the impact of L. rhamnosus on stress-related behaviours, physiology, inflammatory response, cognitive performance and brain activity patterns in healthy male participants. An 8 week, randomized, placebo-controlled, cross-over design was employed. Twenty-nine healthy male volunteers participated. Participants completed self-report stress measures, cognitive assessments and resting electroencephalography (EEG). Plasma IL10, IL1β, IL6, IL8 and TNFα levels and whole blood Toll-like 4 (TLR-4) agonist-induced cytokine release were determined by multiplex ELISA. Salivary cortisol was determined by ELISA and subjective stress measures were assessed before, during and after a socially evaluated cold pressor test (SECPT). Results: There was no overall effect of probiotic treatment on measures of mood, anxiety, stress or sleep quality and no significant effect of probiotic over placebo on subjective stress measures, or the HPA response to the SECPT. Visuospatial memory performance, attention switching, rapid visual information processing, emotion recognition and associated EEG measures did not show improvement over placebo. No significant anti-inflammatory effects were seen as assessed by basal and stimulated cytokine levels. Conclusions: L. rhamnosus was not superior to placebo in modifying stress-related measures, HPA response, inflammation or cognitive performance in healthy male participants. These findings highlight the challenges associated with moving promising preclinical studies, conducted in an anxious mouse strain, to healthy human participants. Future interventional studies investigating the effect of this psychobiotic in populations with stress-related disorders are required.