813 research outputs found

    Numerical calculations of viscous compressible fluid flow over a flat plate and step geometry

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    Computer programs for numerical calculation of viscous compressible fluid flow over flat plat

    Calculation of two-dimensional turbulent flow fields

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    Navier-Stokes equation solutions for two- dimensional turbulent flow fields of compressible viscous flui

    A randomized controlled pilot trial of classroom-based mindfulness meditation compared to an active control condition in sixth-grade children

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    The current study is a pilot trial to examine the effects of a nonelective, classroom-based, teacher-implemented, mindfulness meditation intervention on standard clinical measures of mental health and affect in middle school children. A total of 101 healthy sixth-grade students (55 boys, 46 girls) were randomized to either an Asian history course with daily mindfulness meditation practice (intervention group) or an African history course with a matched experiential activity (active control group). Self-reported measures included the Youth Self Report (YSR), a modified Spielberger State-Trait Anxiety Inventory, and the Cognitive and Affective Mindfulness Measure –Revised. Both groups decreased significantly on clinical syndrome subscales and affect but did not differ in the extent of their improvements. Meditators were significantly less likely to develop suicidal ideation or thoughts of self-harm than controls. These results suggest that mindfulness training may yield both unique and non-specific benefits that are shared by other novel activities

    Gender Differences in Response to a School-Based Mindfulness Training Intervention for Early Adolescents

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    Mindfulness training has been used to improve emotional wellbeing in early adolescents. However, little is known about treatment outcome moderators, or individual differences that may differentially impact responses to treatment. The current study focused on gender as a potential moderator for affective outcomes in response to school-based mindfulness training. Sixth grade students (N = 100) were randomly assigned to either the six weeks of mindfulness meditation or the active control group as part of a history class curriculum. Participants in the mindfulness meditation group completed short mindfulness meditation sessions four to five times per week, in addition to didactic instruction (Asian history). The control group received matched experiential activity in addition to didactic instruction (African history) from the same teacher with no meditation component. Self-reported measures of emotional wellbeing/affect, mindfulness, and self-compassion were obtained at pre and post intervention. Meditators reported greater improvement in emotional wellbeing compared to those in the control group. Importantly, gender differences were detected, such that female meditators reported greater increases in positive affect compared to females in the control group, whereas male meditators and control males displayed equivalent gains. Uniquely among females but not males, increases in self-reported self-compassion were associated with improvements in affect. These findings support the efficacy of school-based mindfulness interventions, and interventions tailored to accommodate distinct developmental needs of female and male adolescents

    Evidence for Calcium Carbonate at the Phoenix Landing Site

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    The Phoenix mission has recently finished its study of the north polar environment of Mars with the aim to help understand both the current climate and to put constraints on past climate. An important part of understanding the past climate is the study of secondary minerals, those formed by reaction with volatile compounds such as H2O and CO2. This work describes observations made by the Thermal and Evolved-Gas Analyzer (TEGA) on the Phoenix Lander related to carbonate minerals. Carbonates are generally considered to be products of aqueous processes. A wet and warmer climate during the early history of Mars coupled with a much denser CO2 atmosphere are ideal conditions for the aqueous alteration of basaltic materials and the subsequent formation of carbonates. Carbonates (Mg- and Ca-rich) are predicted to be thermodynamically stable minerals in the present martian environment, however, there have been only a few indications of carbonates on the surface by a host of orbiting and landed missions to Mars. Carbonates (Mg-rich) have been suggested to be a component (2-5 wt %) of the martian global dust based upon orbital thermal emission spectroscopy. The identifications, based on the presence of a 1480 cm-1 absorption feature, are consistent with Mgcarbonates. A similar feature is observed in brighter, undisturbed soils by Mini-TES on the Gusev plains. Recently, Mg-rich carbonates have been identified in the Nili Fossae region by the CRISM instrument onboard the Mars Reconnaissance Orbiter. Carbonates have also been confirmed as aqueous alteration phases in martian meteorites so it is puzzling why there have not been more discoveries of carbonates by landers, rovers, and orbiters. Carbonates may hold important clues about the history of liquid water and aqueous processes on the surface of Mars

    El programa Cyted: 10 Años de cooperación Iberoaméricana

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    El Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo (CYTED) constituye un interesante ejemplo de continuidad y progreso en la cooperación iberoamericana. El CYTED tiene una serie de características que lo han convertido en un instrumento eficaz dentro del ámbito de la cooperación para el desarrollo, como es la cooperación científica y tecnológica, que requiere un alto grado de perseverancia, rigor y calidad

    Summary of Results from the Mars Phoenix Lander's Thermal Evolved Gas Analyzer

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    The Mars Phoenix Scout Mission with its diverse instrument suite successfully examined several soils on the Northern plains of Mars. The Thermal and Evolved Gas Analyzer (TEGA) was employed to detect evolved volatiles and organic and inorganic materials by coupling a differential scanning calorimeter (DSC) with a magnetic-sector mass spectrometer (MS) that can detect masses in the 2 to 140 dalton range [1]. Five Martian soils were individually heated to 1000 C in the DSC ovens where evolved gases from mineral decompostion products were examined with the MS. TEGA s DSC has the capability to detect endothermic and exothermic reactions during heating that are characteristic of minerals present in the Martian soil

    Geology of McLaughlin Crater, Mars: A Unique Lacustrine Setting with Implications for Astrobiology

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    McLaughlin crater is a 92-kmdiameter Martian impact crater that contained an ancient carbonate- and clay mineral-bearing lake in the Late Noachian. Detailed analysis of the geology within this crater reveals a complex history with important implications for astrobiology [1]. The basin contains evidence for, among other deposits, hydrothermally altered rocks, delta deposits, deep water (>400 m) sediments, and potentially turbidites. The geology of this basin stands in stark contrast to that of some ancient basins that contain evidence for transient aqueous processes and airfall sediments (e.g. Gale Crater [2-3])

    On the Origin of the -4.4 eV Band in CdTe(100)"

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    We calculate the bulk- (infinite system), (100)-bulk-projected- and (100)-Surface-projected Green's functions using the Surface Green's Function Matching method (SGFM) and an empirical tight-binding hamiltonian with tight-binding parameters (TBP) that describe well the bulk band structure of CdTe. In particular, we analyze the band (B--4) arising at --4.4 eV from the top of the valence band at Γ\Gamma according to the results of Niles and H\"ochst and at -4.6 eV according to Gawlik {\it et al.} both obtained by Angle-resolved photoelectron spectroscopy (ARPES). We give the first theoretical description of this band.Comment: 17 pages, Rev-TEX, CIEA-Phys. 02/9

    Study of UV Degradation on Plastic (PET) Aerosols

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    The present study was aimed to explore the impact of UV radiation, from ‘real world’ environmental exposure, on the degradation of plastic PET aerosol containers. Additionally, the intent was to correlate the ‘real world’ environmental exposure to artificial sunlight, using a Xenon-Arc lamp, to develop a simulated test. The standardized methodology could then be used to evaluate the integrity of the plastic aerosol container and product, without the complexity of using ‘real world’ exposure. Through this study, a lab method was developed and validated that would simulate the effect of UV radiation using the Xenon-Arc. Moreover, a correlation was made for conditions inside the Xenon-Arc chamber that were conducive to testing a plastic pressurized container
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