1,102 research outputs found

    Improving the Classroom Experience by Providing Teachers with a Mindfulness Intervention

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    The purpose of this study was to improve the classroom environment for teachers by providing them with a mindfulness-based intervention. This experimental study evaluated the outcomes of an eight-week stress and mindfulness prevention intervention (SPAM) created specifically for teachers. The current study measured the following variables: mindfulness, stress, self-efficacy, job satisfaction, and well-being. This study used a four-way ANOVA (2 X 3 X 2 X 5) with two between subjects’ factors, groups and levels, and two within subjects/repeated measures factors, pre-test-posttest and scales. There were 14 teacher participants in the experimental group and 19 teacher participants in the control group. Although the study did not show any significant effects for mindfulness, stress, self-efficacy, and well-being for either group, teacher participants in the control group demonstrated significantly lower levels of job satisfaction compared to the experimental group from pre-post outcomes. Future directions related to mindfulness-based interventions are discussed and recommendations for researchers, educators, and education administrators are provided

    Lateral Spreading and Stability of Embankments Supported on Fractured Unreinforced High-Modulus Columns

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    Construction of column-supported embankments (CSEs) with unreinforced high-modulus elements is now common practice to accelerate fill placement. These brittle columns are susceptible to column fracturing and CSE designs often limit the degree of lateral spreading such that tensile rupture will not occur, which stems from salient concerns that fracturing may trigger uncontrolled lateral spreading and/or the cessation of intended vertical load transfer. However, tensile rupture is unlikely to coincide with full mobilization of available passive resistance at the toe. Thus, it is disputed in industry whether some degree of column fracturing is tolerable. The objective of this study is to elucidate the influence of column fracturing on lateral spreading and stability of CSEs

    Influence of MWCNT/surfactant dispersions on the mechanical properties of Portland cement pastes

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    This work studies the reinforcing effect of Multi Walled Carbon Nanotubes (MWCNT) on cement pastes. A 0.35% solid concentration of MWCNT in powder was dispersed in deionized water with sodium dodecyl sulfate (cationic surfactant), cetylpyridinium chloride (anionic surfactant) and triton X-100 (amphoteric surfactant) using an ultrasonic tip processor. Three concentrations of each surfactant (1mM, 10mM and 100mM) were tested, and all samples were sonicated until an adequate dispersion degree was obtained. Cement pastes with additions of carbon nanotubes of 0.15% by mass of cement were produced in two steps; first the dispersions of MWCNT were combined with the mixing water using an ultrasonic tip processor to guarantee homogeneity, and then cement was added and mixed until a homogeneous paste was obtained. Direct tensile strength, apparent density and open porosity of the pastes were measured after 7 days of curing. It was found that the MWCNT/surfactants dispersions decrease the mechanical properties of the cement based matrix due to an increased porosity caused by the presence of surfactants. © Published under licence by IOP Publishing Ltd

    An AB effect without closing a loop

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    We discuss the consequences of the Aharonov-Bohm effect in setups involving several charged particles, wherein none of the charged particles encloses a closed loop around the magnetic flux. We show that in such setups, the AB phase is encoded either in the relative phase of a bi-partite or multi-partite entangled photons states, or alternatively, gives rise to an overall AB phase that can be measured relative to another reference system. These setups involve processes of annihilation or creation of electron/hole pairs. We discuss the relevance of such effects in "vacuum Birefringence" in QED, and comment on their connection to other known effects.Comment: 4 pages, 3 figure

    Insecta, Coleoptera, Cerambycidae, Cerambycinae, Trachyderini: New state and country records from South America

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    Based on the revision of the collections of the Museu Nacional, Universidade Federal do Rio de Janeiro andthe National Museum of Natural History, Smithsonian Institution, the current work provides new localities for 32 speciesand two subspecies of Trachyderini from South America. Thirteen new country records from Argentina, Brazil, Colombia,Ecuador, Peru, Surinam and Venezuela and 35 new state records from Brazil are registered

    Coal-CO2 Slurry Feed for Pressurized Gasifiers: Slurry Preparation System Characterization and Economics

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    AbstractGasification-based plants with coal-CO2 slurry feed are predicted to be more efficient than those with coal-water slurry feed. This is particularly true for high moisture, low rank coal such as lignite. Nevertheless, preparation of the CO2 slurry is challenging and the losses associated with this process have not been accounted for in previous analyses. This work introduces the Phase Inversion-based Coal-CO2 Slurry (PHICCOS) feeding system, in which coal-CO2 slurry is prepared at ambient temperature via coal-water slurry. Steady-state process simulation is used to estimate the performance of the proposed slurry preparation and feeding system for bituminous coal and lignite. An Integrated Gasification Combined Cycle (IGCC) power plant with carbon capture is used here as a potential application, but this concept is applicable to any high-pressure coal feeding process. The economic attractiveness of the PHICCOS feeding system is assessed through calculation of its capital costs and resulting levelized cost of electricity, relative to competing commercial technologies. The findings of this work show that the PHICCOS feeding system offers a good tradeoff between overall process performance and costs. It is the most cost-effective method for feeding lignite and the second most attractive for bituminous coal, for which the competing technology is marginally cheaper. The PHICCOS feeding system is hence the only feeding system which is consistently cost-effective across the entire coal rank spectrum and is increasingly so for high-moisture and high-ash coal

    Effects of a Mindfulness Intervention to Improve Teachers’ Well-being

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    Teacher attrition has increased by 50% over the past 15 years. The purpose of this study was to determine whether a mindfulness-based intervention would be effective for reducing stress and increasing mindfulness, self-efficacy, job satisfaction, and well-being among teachers at Title I (low-income) schools. The researchers evaluated the effects of a mindfulness intervention created specifically for teachers using a four-way ANOVA (2 × 3 × 2 × 5) with two between subjects’ factors, groups and levels, and two within subjects/repeated measures factors, pretest-posttest and scales. While the study did not show significant effects for mindfulness, stress, self-efficacy, and well-being, teachers in the control group demonstrated significantly lower levels of job satisfaction compared to the experimental group. These results are commensurate with previous studies that suggest with a mindfulness-based intervention, teachers report increased job satisfaction
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