3,165 research outputs found

    cAMP Signaling Enhances HIV-1 Long Terminal Repeat (LTR)-directed Transcription and Viral Replication in Bone Marrow Progenitor Cells.

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    CD34+ hematopoietic progenitor cells have been shown to be susceptible to HIV-1 infection, possibly due to a low-level expression of CXCR4, a coreceptor for HIV-1 entry. Given these observations, we have explored the impact of forskolin on cell surface expression of CXCR4 in a cell line model (TF-1). The elevation of intracellular cyclic adenosine monophosphate (cAMP) by forskolin through adenylyl cyclase (AC) resulted in transcriptional upregulation of CXCR4 with a concomitant increase in replication of the CXCR4-utilizing HIV-1 strain IIIB. Transient expression analyses also demonstrated an increase in CXCR4-, CCR5-, and CXCR4-/CCR5-utilizing HIV-1 (LAI, YU2, and 89.6, respectively) promoter activity. Studies also implicated the protein kinase A (PKA) pathway and the downstream transcription factor CREB-1 in interfacing with cAMP response elements located in the CXCR4 and viral promoter. These observations suggest that the cAMP signaling pathway may serve as a regulator of CXCR4 levels and concomitantly of HIV-1 replication in bone marrow (BM) progenitor cells. © 2017, © The Author(s) 2017

    Managing Conversation Uncertainty in TutorJ

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    Uncertainty in natural language dialogue is often treated through stochastic models. Some of the authors already presented TutorJ mat is an Intelligent Tutoring System, whose interaction with the user is very intensive, and makes use of both dialogic and graphical modality. When managing the interaction, the system needs to cope with uncertainty due to the understanding of the user's needs and wishes. In this paper we present the extended version of TutorJ, focusing on the new features added to its chatbot module. These features allow to merge deterministic and probabilistic reasoning in dialogue management, and in writing the rules of the system's procedural memory

    Improving Assessment of Students through Semantic Space Construction

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    Assessment is one of the hardest tasks an Intel- ligent Tutoring System has to perform. It involves different and sometimes uncorrelated sub-tasks: building a student model to define her needs, defining tools and procedures to perform tests, understanding students’ replies to system prompts, defining suitable procedures to evaluate the correctness of students’ replies, and strategies to improve students’ abilities after the assessment session. In this work we present an improvement of our system, TutorJ, with particular attention to the assessment phase. Many tutoring systems offer only a limited set of assessment options like multiple-choice questions, fill-in-the-blanks tests or other types of predefined replies obtained through graphical widgets (radio-buttons, text-areas). This limited set of solutions makes interaction poor and unable to satisfy the users’ needs. Our interest is to enrich interaction with dialog in natural language. In this respect, the assessment problem is strictly connected to natural language understanding. The preliminary step is indeed to understand questions and replies of the student. We have reviewed the system design in the framework of a cognitive architecture with the aim to reach a double result: the reduction of the effort for the construction of the knowledge base and the improvement of the system capabilities in the assessment process. To this aim a new common semantic space has been defined and implemented. The entire architecture is oriented to intuitive and natural interaction

    A Map-Based Visualization Tool To Support Tutors In E-Learning 2.0

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    Web 2.0 regards essentially the social issues about the new usage of web applications, but participative web and user generated contents induce a new way to think about the design of the web applications themselves. This is particularly true in the field educational systems that are all web based applications. Many researchers are now devoted to study what is called e-learning 2.0 both as regards the technological issues in the field of computer science, and in relation to the impact of the web 2.0 social and psychological issues on the education process itself. One of the most crucial topics in e-learning 2.0 is the way to provide support to the teacher/tutor to avoid cog- nitive overload when he/she is monitoring the evolution group dynamics inside the class, and decides the proper strategies to ensure the pursuit of the learning goals. Map visualization is a good way to present information without cognitive overload. We present a map-based tool in support of the tutor that is an extension of our ITS called TutorJ. The tool allows a human tutor to have multiple map visualizations about the domain of the course, the social (forum-based) interaction between the students, and the amount of topics faced by each student. The paper reports a detailed description of the architecture of the tool, and a discussion about its relevance in the field of e- learning 2.0

    Understanding Perceptual Judgment in Autism Spectrum Disorder Using the Drift Diffusion Model

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    Objective: Two-alternative forced-choice tasks are widely used to gain insight into specific areas of enhancement or impairment in individuals with autism spectrum disorder (ASD). Data arising from these tasks have been used to support myriad theories regarding the integrity, or otherwise, of particular brain areas or cognitive processes in ASD. The drift diffusion model (DDM) provides an account of the underlying processes which give rise to accuracy and reaction time (RT) distributions, and parameterizes these processes in terms which have direct psychological interpretation. Importantly, the DDM provides further insight into the origin of potential group differences in task performance. Here, for the first time, we used the DDM to investigate perceptual decision making in ASD. Method: Adults with (N = 25) and without ASD (N = 32) performed an orientation discrimination task. A drift diffusion model was applied to the full RT distributions. Results: Participants with ASD responded more slowly than controls, the groups did not differ in accuracy. Modeled parameters indicated that: (a) participants with ASD were more cautious than controls (wider boundary separation); (b) nondecision time was increased in ASD; and (c) the quality of evidence extracted from the stimulus (drift rate) did not vary between groups. Conclusions: Taking the behavioral data in isolation would suggest reduced perceptual sensitivity in ASD. However, DDM results indicated that despite response slowing, there was no evidence of differential perceptual sensitivity between participants with and without ASD. Future use of the DDM in investigations of perception and cognition in ASD is highly recommended. (PsycINFO Database Recor

    Evidence for the speed-value trade-off: human and monkey decision making is magnitude sensitive

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    Complex natural systems from brains to bee swarms have evolved to make adaptive multifactorial decisions. Recent theoretical and empirical work suggests that many evolved systems may take advantage of common motifs across multiple domains. We are particularly interested in value sen- sitivity (i.e., sensitivity to the magnitude or intensity of the stimuli or re- ward under consideration) as a mechanism to resolve deadlocks adaptively. This mechanism favours long-term reward maximization over accuracy in a simple manner, because it avoids costly delays associated with ambivalence between similar options; speed-value trade-offs have been proposed to be evolutionarily advantageous for many kinds of decision. A key prediction of the value-sensitivity hypothesis is that choices between equally-valued options will proceed faster when the options have a high value than when they have a low value. However, value-sensitivity is not part of idealised choice models such as diffusion to bound. Here we examine two different choice behaviours in two different species, perceptual decisions in humans and economic choices in rhesus monkeys, to test this hypothesis. We observe the same value sensitivity in both human perceptual decisions and monkey value-based decisions. These results endorse the idea that neural decision systems make use of the same basic principle of value-sensitivity in order to resolve costly deadlocks and thus improve long-term reward intake

    Functional Studies of CCAAT/Enhancer Binding Protein Site Located Downstream of the Transcriptional Start Site.

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    Previous studies have identified a CCAAT/enhancer binding protein (C/EBP) site located downstream of the transcriptional start site (DS3). The role of the DS3 element with respect to HIV-1 transactivation by Tat and viral replication has not been characterized. We have demonstrated that DS3 was a functional C/EBPβ binding site and mutation of this site to the C/EBP knockout DS3-9C variant showed lower HIV-1 long terminal repeat (LTR) transactivation by C/EBPβ. However, it was able to exhibit similar or even higher transcription levels by Tat compared to the parental LTR. C/EBPβ and Tat together further enhanced the transcription level of the parental LAI-LTR and DS3-9C LTR, with higher levels in the DS3-9C LTR. HIV molecular clone viruses carrying the DS3-9C variant LTR demonstrated a decreased replication capacity and delayed rate of replication. These results suggest that DS3 plays a role in virus transcriptional initiation and provides new insight into C/EBP regulation of HIV-1

    2015-2018 Regional Prevention Plan of Lombardy (Northern Italy) and sedentary prevention: a cross-sectional strategy to develop evidence-based programmes

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    Cross-sector, life-course, and setting approaches are identified in the 2015-2018 Regional Prevention Plan (PRP) of Lombardy Region (Northern Italy) as valuable strategies to ensure the efficacy and sustainable prevention of the non-communicable disease (NCDs). The involvement of non-health sectors in health promotion activities represents a suitable strategy to affect on social, economic, and political determinants and to change environmental factors that could cause NCDs. A dialogue among communities, urban planning, and prevention know-how is a prerequisite to develop a system of policies suitable to promote healthy lifestyle in general and, specifically, active lifestyles. The 2015-2018 Lombardy PRP pursues its aims of health promotion and behavioural risk factors for NCDs prevention through programmes that implement their own setting networks (Health Promoting Schools – SPS; Workplace Health Promotion – WHP) and develop new networks. Sedentary lifestyle prevention and active lifestyle promotion are performed through the approach promoted by the Healthy Cities Programme (WHO), encouraging two main processes: 1. creating integrated capacity-building among health and social prevention services, academic research, and local stakeholders on different urban planning and design issues; 2. promoting community empowerment through active citizens participation. Through this process, Lombardy Region aims to orient its services developing evidence-based programmes and enhancing advocacy and mediating capacity skills in order to create a profitable partnership with non-health sectors. This paper reports the main impact data: 26,000 children that reach school by foot thanks to walking buses, 57% of 145 companies joining WHP are involved in promoting physical activity, 18,891 citizens who attend local walking groups
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