1,844 research outputs found

    The iLearnRW game : support for students with dyslexia in class and at home

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    Dyslexia includes a large variety of literacy-related difficulties which demands, in most cases, a personalised intervention. However, as dyslexia affects a large fraction of the population, schools cannot provide individual care for each student. The iLearnRW game provides a tool for students to work on their literacy skills following a personalised teaching programme. The design of the game and adaptation mechanisms integrated with it are aimed at maintaining student engagement for the duration of an open-ended number of playing sessions, while using a limited quantity of assets and literacy content. By focusing on maintenance of engagement, we hope to improve learning outcomes and motivate students to also play the game outside of school.The authors would like to thank all the participants of the experiments.This research was supported, in part, by the ILearnRW (project no: 318803) FP7 ICT EU project.peer-reviewe

    Azimuthal Anisotropy of Photon and Charged Particle Emission in Pb+Pb Collisions at 158 A GeV/c

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    The azimuthal distributions of photons and charged particles with respect to the event plane are investigated as a function of centrality in Pb + Pb collisions at 158 A GeV/c in the WA98 experiment at the CERN SPS. The anisotropy of the azimuthal distributions is characterized using a Fourier analysis. For both the photon and charged particle distributions the first two Fourier coefficients are observed to decrease with increasing centrality. The observed anisotropies of the photon distributions compare well with the expectations from the charged particle measurements for all centralities.Comment: 8 pages and 6 figures. The manuscript has undergone a major revision. The unwanted correlations were enhanced in the random subdivision method used in the earlier version. The present version uses the more established method of division into subevents separated in rapidity to minimise short range correlations. The observed results for charged particles are in agreement with results from the other experiments. The observed anisotropy in photons is explained using flow results of pions and the correlations arising due to the decay of the neutral pion

    Human SOD2 Modification by Dopamine Quinones Affects Enzymatic Activity by Promoting Its Aggregation: Possible Implications for Parkinson’s Disease

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    Mitochondrial dysfunction and oxidative stress are considered central in dopaminergic neurodegeneration in Parkinson’s disease (PD). Oxidative stress occurs when the endogenous antioxidant systems are overcome by the generation of reactive oxygen species (ROS). A plausible source of oxidative stress, which could account for the selective degeneration of dopaminergic neurons, is the redox chemistry of dopamine (DA) and leads to the formation of ROS and reactive dopamine-quinones (DAQs). Superoxide dismutase 2 (SOD2) is a mitochondrial enzyme that converts superoxide radicals to molecular oxygen and hydrogen peroxide, providing a first line of defense against ROS. We investigated the possible interplay between DA and SOD2 in the pathogenesis of PD using enzymatic essays, site-specific mutagenesis, and optical and high-field-cw-EPR spectroscopies. Using radioactive DA, we demonstrated that SOD2 is a target of DAQs. Exposure to micromolar DAQ concentrations induces a loss of up to 50% of SOD2 enzymatic activity in a dose-dependent manner, which is correlated to the concomitant formation of protein aggregates, while the coordination geometry of the active site appears unaffected by DAQ modifications. Our findings support a model in which DAQ-mediated SOD2 inactivation increases mitochondrial ROS production, suggesting a link between oxidative stress and mitochondrial dysfunction

    Comparative efficacy of two poeciliid fish in indoor cement tanks against chikungunya vector Aedes aegypti in villages in Karnataka, India

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    <p>Abstract</p> <p>Background</p> <p>In 2006, severe outbreaks of <it>Aedes aegypti</it>-transmitted chikungunya occurred in villages in Karnataka, South India. We evaluated the effectiveness of combined information, education and communication (IEC) campaigns using two potential poeciliid larvivorous fish guppy (<it>Poecilia reticulata</it>) and mosquitofish (<it>Gambusia affinis</it>), in indoor cement tanks for <it>Aedes </it>larval control.</p> <p>Methods</p> <p>Trials were conducted in two villages (Domatmari and Srinivaspura) in Tumkur District from March to May 2006 for <it>Poecilia </it>and one village (Balmanda) in Kolar District from July to October 2006 for <it>Gambusia</it>. A survey on knowledge, attitude and practice (KAP) on chikungunya was initially conducted and IEC campaigns were performed before and after fish release in Domatmari (IEC alone, followed by IEC + <it>Poecilia</it>) and Balmanda (IEC + <it>Gambusia</it>). In Srinivaspura, IEC was not conducted. Larval surveys were conducted at the baseline followed by one-week and one-month post-intervention periods. The impact of fish on <it>Aedes </it>larvae and disease was assessed based on baseline and post-intervention observations.</p> <p>Results</p> <p>Only 18% of respondents knew of the role of mosquitoes in fever outbreaks, while almost all (<it>n </it>= 50 each) gained new knowledge from the IEC campaigns. In Domatmari, IEC alone was not effective (OR 0.54; <it>p </it>= 0.067). Indoor cement tanks were the most preferred <it>Ae. aegypti </it>breeding habitat (86.9%), and had a significant impact on <it>Aedes </it>breeding (Breteau Index) in all villages in the one-week period (<it>p </it>< 0.001). In the one-month period, the impact was most sustained in Domatmari (OR 1.58, <it>p </it>< 0.001) then Srinivaspura (OR 0.45, <it>p </it>= 0.063) and Balmanda (OR 0.51, <it>p </it>= 0.067). After fish introductions, chikungunya cases were reduced by 99.87% in Domatmari, 65.48% in Srinivaspura and 68.51% in Balmanda.</p> <p>Conclusions</p> <p><it>Poecilia </it>exhibited greater survival rates than <it>Gambusia </it>(86.04 <it>vs</it>.16.03%) in cement tanks. Neither IEC nor <it>Poecilia </it>alone was effective against <it>Aedes </it>(<it>p </it>> 0.05). We conclude that <it>Poecilia </it>+ IEC is an effective intervention strategy. The operational cost was 0.50 (US0.011,1US 0.011, 1 US= 47) per capita per application. Proper water storage practices, focused IEC with <it>Poecilia </it>introductions and vector sanitation involving the local administration and community, is suggested as the best strategy for <it>Aedes </it>control.</p

    Threshold production of unstable top

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    We develop a systematic approach to describe the finite lifetime effects in the threshold production of top quark-antiquark pairs. It is based on the nonrelativistic effective field theory with an additional scale rho^(1/2) m_t characterizing the dynamics of the top-quark decay, which involves a new expansion parameter rho=1-m_W/m_t. Our method naturally resolves the problem of spurious divergences in the analysis of the unstable top production. Within this framework we compute the next-to-leading nonresonant contribution to the total cross section of the top quark-antiquark threshold production in electron-positron annihilation through high-order expansion in rho and confirm the recently obtained result. We extend the analysis to the next-to-next-to-leading O(alpha_s) nonresonant contribution which is derived in the leading order in rho. The dominant nonresonant contribution to the top-antitop threshold production in hadronic collisions is also obtained.Comment: 20 pages, 7 figures; v2: added a section on invariant mass cuts and one reference, minor changes in Introduction, results unchanged, matches published versio

    Production of phi mesons at mid-rapidity in sqrt(s_NN) = 200 GeV Au+Au collisions at RHIC

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    We present the first results of meson production in the K^+K^- decay channel from Au+Au collisions at sqrt(s_NN) = 200 GeV as measured at mid-rapidity by the PHENIX detector at RHIC. Precision resonance centroid and width values are extracted as a function of collision centrality. No significant variation from the PDG accepted values is observed. The transverse mass spectra are fitted with a linear exponential function for which the derived inverse slope parameter is seen to be constant as a function of centrality. These data are also fitted by a hydrodynamic model with the result that the freeze-out temperature and the expansion velocity values are consistent with the values previously derived from fitting single hadron inclusive data. As a function of transverse momentum the collisions scaled peripheral.to.central yield ratio RCP for the is comparable to that of pions rather than that of protons. This result lends support to theoretical models which distinguish between baryons and mesons instead of particle mass for explaining the anomalous proton yield.Comment: 326 authors, 24 pages text, 23 figures, 6 tables, RevTeX 4. To be submitted to Physical Review C as a regular article. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    1Identification of genes differentially expressed in the embryonic pig cerebral cortex before and after appearance of gyration

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    <p>Abstract</p> <p>Background</p> <p>Mammalian evolution is characterized by a progressive expansion of the surface area of the cerebral cortex, an increase that is accompanied by gyration of the cortical surface. The mechanisms controlling this gyration process are not well characterized but mutational analyses indicate that genes involved in neuronal migration play an important function. Due to the lack of gyration of the rodent brain it is important to establish alternative models to examine brain development during the gyration process. The pig brain is gyrated and accordingly is a candidate alternative model.</p> <p>Findings</p> <p>In this study we have identified genes differentially expressed in the pig cerebral cortex before and after appearance of gyration. Pig cortical tissue from two time points in development representing a non-folded, lissencephalic, brain (embryonic day 60) and primary-folded, gyrencephalic, brain (embryonic day 80) were examined by whole genome expression microarray studies. 91 differentially expressed transcripts (fold change >3) were identified. 84 transcripts were annotated and encoding proteins involved in for example neuronal migration, calcium binding, and cytoskeletal structuring. Quantitative real-time PCR was used to confirm the regulation of a subset of the identified genes.</p> <p>Conclusion</p> <p>This study provides identification of genes which are differentially expressed in the pig cerebral cortex before and after appearance of brain gyration. The identified genes include novel candidate genes which could have functional importance for brain development.</p

    Ultrafast isomerization initiated by X-ray core ionization

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    Rapid proton migration is a key process in hydrocarbon photochemistry. Charge migration and subsequent proton motion can mitigate radiation damage when heavier atoms absorb X-rays. If rapid enough, this can improve the fidelity of diffract-before-destroy measurements of biomolecular structure at X-ray-free electron lasers. Here we study X-ray-initiated isomerization of acetylene, a model for proton dynamics in hydrocarbons. Our time-resolved measurements capture the transient motion of protons following X-ray ionization of carbon K-shell electrons. We Coulomb-explode the molecule with a second precisely delayed X-ray pulse and then record all the fragment momenta. These snapshots at different delays are combined into a ‘molecular movie’ of the evolving molecule, which shows substantial proton redistribution within the first 12 fs. We conclude that significant proton motion occurs on a timescale comparable to the Auger relaxation that refills the K-shell vacancy

    Comparison between two methods of working length determination and its effect on radiographic extent of root canal filling: a clinical study [ISRCTN71486641]

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    BACKGROUND: Obtaining a correct working length is critical to the success of endodontic therapy. Different methods have been used to identify this crucial measurement. The Aim of this clinical study was to compare the effect of working length determination using apex locator alone or in combination with working length radiograph on the apical extent of root canal filling. METHODS: A total number of 66 patients, 151 canals were randomized into two groups, In group (I) working length was determined by apex locator alone, while in group (II) working length was determined by apex locator confirmed by working length radiograph, length of obturation was assessed, and the total number of radiographs was recorded. The data were analyzed using SAS system and T. tests were carried out. Statistical significance was considered to be P ≤ 0.05. RESULTS: Sixty seven canals in group I were treated with a mean distance from the tip of root canal filling to radiographic apex -0.5 mm ± 0.5 and a mean of a total number of radiographs of 2.0, while in group II eighty four canals were treated with a mean distance from the tip of root canal filling to radiographic apex -0.4 mm ± 0.5 and a mean of a total number of radiographs of 3.2. There was no statistically significant difference in the mean distance from the tip of root filling to radiographic apex between group I and group II (P > 0.05). CONCLUSION: The practice of using electronic apex locator in the determination of working length is useful and reliable with no statistical difference of the radiographic extent of root canal filling when using apex locator alone or in combination with working length radiograph. Under the clinical conditions of this study, it is suggested that the correct use of an apex locator alone could prevent the need for further diagnostic radiographs for determination of working length. This method can be useful in patients who need not to be exposed to repeated radiation because of mental, medical or oral conditions

    Search for Kaluza-Klein Graviton Emission in ppˉp\bar{p} Collisions at s=1.8\sqrt{s}=1.8 TeV using the Missing Energy Signature

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    We report on a search for direct Kaluza-Klein graviton production in a data sample of 84 pb1{pb}^{-1} of \ppb collisions at s\sqrt{s} = 1.8 TeV, recorded by the Collider Detector at Fermilab. We investigate the final state of large missing transverse energy and one or two high energy jets. We compare the data with the predictions from a 3+1+n3+1+n-dimensional Kaluza-Klein scenario in which gravity becomes strong at the TeV scale. At 95% confidence level (C.L.) for nn=2, 4, and 6 we exclude an effective Planck scale below 1.0, 0.77, and 0.71 TeV, respectively.Comment: Submitted to PRL, 7 pages 4 figures/Revision includes 5 figure
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