2,532 research outputs found

    The decays h+- -> W-+ h0(a0) within an extension of the MSSM with one complex Higgs triplet

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    The vertex H+-W-+h0, involving the gauge bosons W-+, the charged (H+-) and the lightest neutral (h0) Higgs bosons, arises within the context of many extensions of the SM, and it can be used to probe the Higgs sector of such extensions via the decay H+- -> W+- h0. We discuss the strength of this vertex for an extension of the MSSM with an additional complex Higgs triplet. By using this model, we find regions of the parameter space where the decay H+- -> W+- h0 is not only kinematically allowed, but it also becomes an important decay mode and in some cases the dominant one.Comment: 10 figure

    Supporting teachers in collaborative student modeling: a framework and an implementation

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    Collaborative student modeling in adaptive learning environments allows the learners to inspect and modify their own student models. It is often considered as a collaboration between students and the system to promote learners’ reflection and to collaboratively assess the course. When adaptive learning environments are used in the classroom, teachers act as a guide through the learning process. Thus, they need to monitor students’ interactions in order to understand and evaluate their activities. Although, the knowledge gained through this monitorization can be extremely useful to student modeling, collaboration between teachers and the system to achieve this goal has not been considered in the literature. In this paper we present a framework to support teachers in this task. In order to prove the usefulness of this framework we have implemented and evaluated it in an adaptive web-based educational system called PDinamet.Postprint (author's final draft

    Fast determination of toxic diethylene glycol in toothpaste by ultra-performance liquid chromatography–time of flight mass spectrometry

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    A rapid method for determining diethylene glycol (DEG) in toothpaste based on the use of ultraperformance liquid chromatography (UPLC) coupled to time-of-flight mass spectrometry (TOF-MS) has been developed. The method has been validated in toothpaste samples spiked at different levels, 0.005, 0.1 and 5%, obtaining satisfactory recoveries (74–98%) and relative standard deviations (<4%). Quantification was carried out by using matrix-matched standards calibration. The developed method was applied to several types of toothpaste, making identification and quantification of DEG and other polyethylene glycols (PEG) feasible with very little sample manipulation, as only extraction with water is required. The excellent sensitivity of TOF-MS analysis performed in fullscan acquisition mode allowed the determination of DEG at concentration levels as low as 0.005% in samples and its reliable identification via the mass accuracy measurements provided by this instrument (<5 ppm
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