599 research outputs found

    Analyzing Laminated Structures from Fibre-Reinforced Composite Material: An Assessment

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    In the open literature there is available a tremendous number of models and methods for analyzing laminated structures. With respect to the assumptions across the laminate thickness, theories with Cz1-continuous functions are to be distinguished from layer-wise approaches, where for the latter the functional degrees of freedom can be dependent or independent of the number of layers. Transverse shear and normal stresses are more accurate when obtained by locally evaluating the equilibrium conditions. Guidelines are needed as to which model is suitable for what task. Especially for layer-wise models a fair judgment is missing. To ease up this deficiency two simple layer-wise models are evaluated and compared with models based on Cz1-continuous functions. It turns out that for standard application the FSDT with improved transverse shear stiffness is a good choice with respect to efficiency

    The Effect of Student-Directed Transition Planning With a Computer-Based Reading Support Program on the Self-Determination of Students With Disabilities

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    The purpose of this study was to investigate the impact of student-directed transition planning instruction (Whose Future Is It Anyway? curriculum) with a computer-based reading support program (Rocket Reader) on the self-determination, self-efficacy and outcome expectancy, and transition planning knowledge of students with disabilities. This study employed a pre- and postmeasure design with 168 middle school students with disabilities who were assigned to an experimental group (n = 86) and control group (n = 82). The results of the study demonstrated that self-determination, self-efficacy, and outcome expectancy for education planning improved through the application of Rocket Reader . Avenues are discussed for promoting middle school students’ self-determination in their transition planning, as are implications for future research.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Die Àrztliche AufklÀrungspflicht in der zahnÀrztlichen Implantologie in Deutschland, England und den USA: Eine rechtsvergleichende Analyse

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    Diese Arbeit untersucht die Möglichkeit, einen Leitfaden fĂŒr die AufklĂ€rungspflicht in der Implantologie so zu formulieren, dass sich daraus ein auch aus juristischer Sicht praxistaugliches Konzept ergibt. DafĂŒr wird sowohl die allgemein-Ă€rztliche als auch die zahnmedizinisch/implantologische AufklĂ€rungspflicht, eingebettet in die verschiedenen Rechtssysteme, in Deutschland, England und in den USA dargestellt und verglichen. Eine Möglichkeit, die AufklĂ€rung zu systematisieren, ist die Hinwendung zu einem AufklĂ€rungsstandard, der den verstĂ€ndigen Patienten nach dem amerikanischen Vorbild des „reasonable patient“ als Hintergrund hat. Gleichzeitig könnte eine sowohl von Medizinern als auch von Vertretern der Rechtsprechung gemeinsam vorgenommene Katalogisierung erforderlicher AufklĂ€rungsaspekte eine Basis fĂŒr das AufklĂ€rungsgesprĂ€ch schaffen. Entscheidend dabei wĂ€re die rechtliche Verbindlichkeit, so dass zumindest in den GrundsĂ€tzen der AufklĂ€rung keine Unsicherheiten mehr bestĂŒnden

    Insights from the classical MD simulations

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    Salt bridges and ionic interactions play an important role in protein stability, protein-protein interactions, and protein folding. Here, we provide the classical MD simulations of the structure and IR signatures of the arginine (Arg)–glutamate (Glu) salt bridge. The Arg-Glu model is based on the infinite polyalanine antiparallel two-stranded ÎČ-sheet structure. The 1 ÎŒs NPT simulations show that it preferably exists as a salt bridge (a contact ion pair). Bidentate (the end-on and side-on structures) and monodentate (the backside structure) configurations are localized [Donald et al., Proteins 79, 898–915 (2011)]. These structures are stabilized by the short +N–H⋯O− bonds. Their relative stability depends on a force field used in the MD simulations. The side-on structure is the most stable in terms of the OPLS-AA force field. If AMBER ff99SB-ILDN is used, the backside structure is the most stable. Compared with experimental data, simulations using the OPLS all-atom (OPLS-AA) force field describe the stability of the salt bridge structures quite realistically. It decreases in the following order: side-on > end-on > backside. The most stable side-on structure lives several nanoseconds. The less stable backside structure exists a few tenth of a nanosecond. Several short-living species (solvent shared, completely separately solvated ionic groups ion pairs, etc.) are also localized. Their lifetime is a few tens of picoseconds or less. Conformational flexibility of amino acids forming the salt bridge is investigated. The spectral signature of the Arg-Glu salt bridge is the IR-intensive band around 2200 cm−1. It is caused by the asymmetric stretching vibrations of the +N–H⋯O− fragment. Result of the present paper suggests that infrared spectroscopy in the 2000–2800 frequency region may be a rapid and quantitative method for the study of salt bridges in peptides and ionic interactions between proteins. This region is usually not considered in spectroscopic studies of peptides and proteins

    Using failed supernovae to constrain the Galactic r-process element production

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    Rapid neutron capture process (r-process) elements have been detected in a large fraction of metal-poor halo stars, with abundances relative to iron (Fe) that vary by over two orders of magnitude. This scatter is reduced to less than a factor of 3 in younger Galactic disc stars. The large scatter of r-process elements in the early Galaxy suggests that the r-process is made by rare events, like compact binary mergers and rare sub-classes of supernovae. Although being rare, neutron star mergers alone have difficulties to explain the observed enhancement of r-process elements in the lowest metallicity stars compared to Fe. The supernovae producing the two neutron stars already provide a substantial Fe abundance where the r-process ejecta from the merger would be injected. In this work we investigate another complementary scenario, where the r-process occurs in neutron star-black hole mergers in addition to neutron star mergers. Neutron star-black hole mergers would eject similar amounts of r-process matter as neutron star mergers, but only the neutron star progenitor would have produced Fe. Furthermore, a reduced efficiency of Fe production from single stars significantly alters the age-metallicity relation, which shifts the onset of r-process production to lower metallicities. We use the high-resolution [(20 pc)3/cell] inhomogeneous chemical evolution tool `ICE' to study the outcomes of these effects. In our simulations, an adequate combination of neutron star mergers and neutron star-black hole mergers qualitatively reproduces the observed r-process abundances in the Galaxy

    Establishing a Causal Relationship Between Intervention to Promote Self-Determination and Enhanced Student Self-Determination

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    Promoting the self-determination of adolescents with disabilities has become best practice in secondary education and transition services, but to date there have been no studies establishing a causal relationship between efforts to promote self-determination and enhancement of the self-determination of youth with disabilities. This article reports a randomized trial placebo control group study of 371 high school students receiving special education services under the categorical areas of mental retardation or learning disabilities. Students were randomly assigned to an intervention or control group (by high school campus), with students in the intervention condition receiving multiple instructional components to promote self-determination. Latent growth curve analysis showed that although all students in the study showed improved self-determination over the 3 years of the study, students in the intervention group showed significantly greater growth, though specific intraindividual variables affected this growth. Implications for research and intervention are discussed.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Effect of Intervention With the Self-Determined Learning Model of Instruction on Access and Goal Attainment

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    Promoting self-determination has been identified as best practice in special education and transition services and as a means to promote goal attainment and access to the general education curriculum for students with disabilities. There have been, however, limited evaluations of the effects of interventions to promote self-determination on outcomes related to access to the general education curriculum. This article reports findings from a cluster or group-randomized trial control group study examining the impact of intervention using the Self-Determined Learning Model of Instruction on students’ academic and transition goal attainment and on access to the general education curriculum for students with intellectual disability and learning disabilities. Findings support the efficacy of the model for both goal attainment and access to the general education curriculum, though students varied in the patterns of goal attainment as a function of type of disability.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    An Evaluation of the Beyond High School Model on the Self- Determination of Students With Intellectual Disability

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    Students with intellectual disability are often served in community-based services to promote effective adult outcomes in employment, community inclusion, and independent living (Gaumer, Morningstar & Clark (2004). Beyond High School (Wehmeyer, Garner, Lawrence, Yeager, & Davis, 2006), a multi-stage model to promote student involvement in educational planning, was effectively used by 109 students with mild and moderate levels of intellectual disability between 17.8 and 21 years of age to increase student abilities. Results are discussed in regard to improved transition opportunities for individuals with intellectual disability such as those afforded through post-secondary education.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Introduction to Markov state modeling with the PyEMMA software — v1.0

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    This tutorial provides an introduction to the construction of Markov models of molec- ular kinetics from molecular dynamics trajectory data with the PyEMMA software. Using tutorial notebooks, we will guide the user through the basic functionality as well as the more common advanced mechanisms. Short exercises to self check the learning progress and a notebook on troubleshooting complete this basic introduction

    Markov State Models from short non-Equilibrium Simulations - Analysis and Correction of Estimation Bias

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    Many state-of-the-art methods for the thermodynamic and kinetic characterization of large and complex biomolecular systems by simulation rely on ensemble approaches, where data from large numbers of relatively short trajectories are integrated. In this context, Markov state models (MSMs) are extremely popular because they can be used to compute stationary quantities and long-time kinetics from ensembles of short simulations, provided that these short simulations are in “local equilibrium” within the MSM states. However, over the last 15 years since the inception of MSMs, it has been controversially discussed and not yet been answered how deviations from local equilibrium can be detected, whether these deviations induce a practical bias in MSM estimation, and how to correct for them. In this paper, we address these issues: We systematically analyze the estimation of MSMs from short non-equilibrium simulations, and we provide an expression for the error between unbiased transition probabilities and the expected estimate from many short simulations. We show that the unbiased MSM estimate can be obtained even from relatively short non-equilibrium simulations in the limit of long lag times and good discretization. Further, we exploit observable operator model (OOM) theory to derive an unbiased estimator for the MSM transition matrix that corrects for the effect of starting out of equilibrium, even when short lag times are used. Finally, we show how the OOM framework can be used to estimate the exact eigenvalues or relaxation time scales of the system without estimating an MSM transition matrix, which allows us to practically assess the discretization quality of the MSM. Applications to model systems and molecular dynamics simulation data of alanine dipeptide are included for illustration. The improved MSM estimator is implemented in PyEMMA of version 2.3
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