926 research outputs found

    Developing Prognosis Tools to Identify Learning Difficulties in Children Using Machine Learning Technologies

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    The Mental Attributes Profiling System was developed in 2002 (Laouris and Makris, Proceedings of multilingual & cross-cultural perspectives on Dyslexia, Omni Shoreham Hotel, Washington, D.C, 2002), to provide a multimodal evaluation of the learning potential and abilities of young children’s brains. The method is based on the assessment of non-verbal abilities using video-like interfaces and was compared to more established methodologies in (Papadopoulos, Laouris, Makris, Proceedings of IDA 54th annual conference, San Diego, 2003), such as the Wechsler Intelligence Scale for Children (Watkins et al., Psychol Sch 34(4):309–319, 1997). To do so, various tests have been applied to a population of 134 children aged 7–12 years old. This paper addresses the issue of identifying a minimal set of variables that are able to accurately predict the learning abilities of a given child. The use of Machine Learning technologies to do this provides the advantage of making no prior assumptions about the nature of the data and eliminating natural bias associated with data processing carried out by humans. Kohonen’s Self Organising Maps (Kohonen, Biol Cybern 43:59–69, 1982) algorithm is able to split a population into groups based on large and complex sets of observations. Once the population is split, the individual groups can then be probed for their defining characteristics providing insight into the rationale of the split. The characteristics identified form the basis of classification systems that are able to accurately predict which group an individual will belong to, using only a small subset of the tests available. The specifics of this methodology are detailed herein, and the resulting classification systems provide an effective tool to prognose the learning abilities of new subjects

    Random walk with barriers: Diffusion restricted by permeable membranes

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    Restrictions to molecular motion by barriers (membranes) are ubiquitous in biological tissues, porous media and composite materials. A major challenge is to characterize the microstructure of a material or an organism nondestructively using a bulk transport measurement. Here we demonstrate how the long-range structural correlations introduced by permeable membranes give rise to distinct features of transport. We consider Brownian motion restricted by randomly placed and oriented permeable membranes and focus on the disorder-averaged diffusion propagator using a scattering approach. The renormalization group solution reveals a scaling behavior of the diffusion coefficient for large times, with a characteristically slow inverse square root time dependence. The predicted time dependence of the diffusion coefficient agrees well with Monte Carlo simulations in two dimensions. Our results can be used to identify permeable membranes as restrictions to transport in disordered materials and in biological tissues, and to quantify their permeability and surface area.Comment: 8 pages, 3 figures; origin of dispersion clarified, refs adde

    Efficacy of Management Skills Group Training for Mothers on Self-Esteem and Anxiety of Their Children With Attention Deficit and Hyperactivity Disorder

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    Background: Attention deficit and hyperactivity disorder (ADHD) has a profound impact on lives of thousands of children and their families. Objectives: Aim of this study was to determine effectiveness of training for mothers, on these children. Materials and Methods: In this quasi-experimental research, 30 mothers were randomly divided into control and experimental groups and the experimental group received Barkley management skills training in 9 sessions. Results: Findings showed that anxiety in children of trained mothers was decreased and self-esteem was increased. Conclusions: The training program for mothers can be an effective method for treatment of psychological disorders in children with ADHD

    Emergence of Variability in Isogenic Escherichia coli Populations Infected by a Filamentous Virus

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    The spread of epidemics not only depends on the average number of parasites produced per host, but also on the existence of highly infectious individuals. It is widely accepted that infectiousness depends on genetic and environmental determinants. However, even in clonal populations of host and viruses growing in homogeneous conditions, high variability can exist. Here we show that Escherichia coli cells commonly display high differentials in viral burst size, and address the kinetics of emergence of such variability with the non-lytic filamentous virus M13. By single-cell imaging of a virally-encoded fluorescent reporter, we monitor the viral charge distribution in infected bacterial populations at different time following infection. A mathematical model assuming autocatalytic virus replication and inheritance of bacterial growth rates quantitatively reproduces the experimental distributions, demonstrating that deterministic amplification of small host inhomogeneities is a mechanism sufficient to explain large and highly skewed distributions. This mechanism of amplification is general and may occur whenever a parasite has an initial phase of exponential growth within its host. Moreover, it naturally reproduces the shift towards higher virulence when the host is experimenting poor conditions, as observed commonly in host-parasite systems

    Molecular mechanisms of extracellular adenine nucleotides-mediated inhibition of human Cd4+ T lymphocytes activation

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    We have previously reported that ATPγS, a slowly hydrolyzed analog of ATP, inhibits the activation of human CD4+ T lymphocytes by anti-CD3 and anti-CD28 mAb. In this report we have partially characterized the signaling mechanisms involved in this immunosuppressive effect. ATPγS had no inhibitory effect on CD4+ T-cell activation induced by PMA and anti-CD28, indicating that it acts proximally to the TCR. It had no effect on the calcium rise induced by CD3/CD28 stimulation, but inhibited the phosphorylation of three kinases, ERK2, p38 MAPK and PKB, that play a key role in the activation of T cells. The receptor involved in these actions remains unidentified
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