518 research outputs found

    Reflective Practice of a Hispanic Chief Financial Officer and Interim Superintendent in a Predominantly Hispanic South Texas School District

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    Reflective practice has been utilized in many fields. Education studies have recommended that reflexivity be used to enhance the practice of principals, teachers, and counselors. There has been little research in the area of reflective practice for superintendents and chief financial officers (CFOs) and the linking of Schön’s reflective practice with Mezirow’s transformative learning. Therefore, this study was aimed at examining my critical events and the use of reflective practice to improve professional development for superintendents and/or CFOs. The study was a first-person account of my experiences in a predominantly Hispanic South Texas school district. My autoethnography allowed me to be the primary participant and researcher in the study, and I used three types of reflective practice (reflection-in-action, reflection-on-action, and reflection-for-action) to narrate the critical events during my district tenure. Data collection included conducting a series of semistructured interviews with my committee chair, reviewing artifacts such as video tapes and board reports, and reflections from my journal. I ensured trustworthiness through data triangulation, thick description, and reflective journaling. My analysis included examining the data using Schön’s reflective practice and Mezirow’s precursors of transformative learning to identify disorienting dilemmas and examine my thinking, emotions, and reactions to the critical events and experiences. I identified five themes that were salient to my study: (a) disrespect, (b) ethical dilemmas, (c) politics, (d) bullying and oppression, and (e) change. Three suggestions to the adult learning process that will aid educational strategies for superintendents and CFOs have been identified: (a) that a chief financial officer not consider being an interim superintendent because being in such a position might create political situations, (b) that a new reflective practice model be considered where reflection-for-action (RFA) is used as a planning tool knowing that we are always in the reflection-in-action (RIA) mode, and (c) that journaling and peer discussions be used as a way to reflect on experience. The autoethnography should be carefully examined for limitations and personal interpretations. I believe that my stories will contribute to the preparation and practice of superintendents and CFOs as well as future research, and my stories are discussed herein

    Methodology for deriving the telescope focus function and its uncertainty for a heterodyne pulsed Doppler lidar

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    Doppler lidars provide two measured parameters, radial velocity and signal-to-noise ratio, from which winds and turbulent properties are routinely derived. Attenuated backscatter, which gives quantitative information on aerosols, clouds, and precipitation in the atmosphere, can be used in conjunction with the winds and turbulent properties to create a sophisticated classification of the state of the atmospheric boundary layer. Calculating attenuated backscatter from the signal-to-noise ratio requires accurate knowledge of the telescope focus function, which is usually unavailable. Inaccurate assumptions of the telescope focus function can significantly deform attenuated backscatter profiles, even if the instrument is focused at infinity. Here, we present a methodology for deriving the telescope focus function using a co-located ceilometer for pulsed heterodyne Doppler lidars. The method was tested with Halo Photonics StreamLine and StreamLine XR Doppler lidars but should also be applicable to other pulsed heterodyne Doppler lidar systems. The method derives two parameters of the telescope focus function, the effective beam diameter and the effective focal length of the telescope. Additionally, the method provides uncertainty estimates for the retrieved attenuated backscatter profile arising from uncertainties in deriving the telescope function, together with standard measurement uncertainties from the signal-to-noise ratio. The method is best suited for locations where the absolute difference in aerosol extinction at the ceilometer and Doppler lidar wavelengths is small.Peer reviewe

    Evaluating wind profiles in a numerical weather prediction model with Doppler lidar

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    We use Doppler lidar wind profiles from six locations around the globe to evaluate the wind profile forecasts in the boundary layer generated by the operational global Integrated Forecast System (IFS) from the European Centre for Medium-range Weather Forecasts (ECMWF). The six locations selected cover a variety of surfaces with different characteristics (rural, marine, mountainous urban, and coastal urban). We first validated the Doppler lidar observations at four locations by comparison with co-located radiosonde profiles to ensure that the Doppler lidar observations were of sufficient quality. The two observation types agree well, with the mean absolute error (MAE) in wind speed almost always less than 1 m s−1. Large deviations in the wind direction were usually only seen for low wind speeds and are due to the wind direction uncertainty increasing rapidly as the wind speed tends to zero. Time–height composites of the wind evaluation with 1 h resolution were generated, and evaluation of the model winds showed that the IFS model performs best over marine and coastal locations, where the mean absolute wind vector error was usually less than 3 m s−1 at all heights within the boundary layer. Larger errors were seen in locations where the surface was more complex, especially in the wind direction. For example, in Granada, which is near a high mountain range, the IFS model failed to capture a commonly occurring mountain breeze, which is highly dependent on the sub-grid-size terrain features that are not resolved by the model. The uncertainty in the wind forecasts increased with forecast lead time, but no increase in the bias was seen. At one location, we conditionally performed the wind evaluation based on the presence or absence of a low-level jet diagnosed from the Doppler lidar observations. The model was able to reproduce the presence of the low-level jet, but the wind speed maximum was about 2 m s−1 lower than observed. This is attributed to the effective vertical resolution of the model being too coarse to create the strong gradients in wind speed observed. Our results show that Doppler lidar is a suitable instrument for evaluating the boundary layer wind profiles in atmospheric models.</p

    Development and Evaluation of a Borohydride-palladium System for Selective Reduction of the C=C Bond of α,β-unsaturated Carbonyl Compounds

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    Selective reduction of the carbon-carbon double bond of α,β-unsaturated carbonyl compounds is most commonly and reliably effected using a palladium metal catalyst together with molecular hydrogen from a pressurized tank. Sodium borohydride, like other hydrides, is ordinarily associated with reduction of the more polarized carbonyl of such compounds. However, we have developed an alternative means of employing sodium borohydride in combination with palladium metal to selectively reduce the carbon-carbon double bonds of these compounds. In this survey study, we introduce sodium borohydride as an alternative hydrogen source for such selective, palladium-catalyzed reductions. We also compare the results of this new, heterogeneous borohydride-palladium method with that of traditional palladium-catalyzed hydrogenation. A third method using only sodium borohydride with no palladium is included for comparison.Faculty Sponsor: Dr. David B. Corde

    Multi-stage generation of extreme ultraviolet dispersive waves by tapering gas-filled hollow-core anti-resonant fibers

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    In this work, we numerically investigate an experimentally feasible design of a tapered Ne-filled hollow-core anti-resonant fiber and we report the generation of multiple dispersive waves (DWs) in the range 90-120 nm, well into the extreme ultraviolet (UV) region. The simulations assume an 800 nm pump pulse with 30 fs 10 μ\muJ pulse energy, launched into a 9 bar Ne-filled fiber with 34 μ34~\mum initial core diameter that is then tapered to a 10 μ10~\mum core diameter. The simulations were performed using a new model that provides a realistic description of both loss and dispersion of the resonant and anti-resonant spectral bands of the fiber, and also importantly includes the material loss of silica in the UV. We show that by first generating solitons that emit DWs in the far-UV region in the pre-taper section, optimization of the following taper structure can allow re-collision with the solitons and further up-conversion of the far-UV DWs to the extreme-UV with energies up to 190 nJ in the 90-120 nm range. This process provides a new way to generate light in the extreme-UV spectral range using relatively low gas pressure

    Las mujeres en la industria del cine de México

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    En esta investigación se habla del recorrido de la mujer por la industria cinematográfica en México hasta llegar a nuestros días, y se enfoca en los temas sobre los cuales las mujeres directoras hablan en sus películas. Por medio de entrevistas a cuatro directoras se analizan las temáticas y narrativas que han llevado recientemente a la pantalla. También se aborda el progreso, la importancia y la significación que tienen las mujeres en el ámbito del cine.ITESO, A.C

    Wind and Turbulence Statistics in the Urban Boundary Layer over a Mountain–Valley System in Granada, Spain

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    Urban boundary layer characterization is currently a challenging and relevant issue, because of its role in weather and air quality modelling and forecast. In many cities, the effect of complex topography at local scale makes this modelling even more complicated. This is the case of mid-latitude urban areas located in typical basin topographies, which usually present low winds and high turbulence within the atmospheric boundary layer (ABL). This study focuses on the analysis of the first ever measurements of wind with high temporal and vertical resolution throughout the ABL over a medium-sized city surrounded by mountains in southern Spain. These measurements have been gathered with a scanning Doppler lidar system and analyzed using the Halo lidar toolbox processing chain developed at the Finnish Meteorological Institute. We have used the horizontal wind product and the ABL turbulence classification product to carry out a statistical study using a two-year database. The data availability in terms of maximum analyzed altitudes for statistically significant results was limited to around 1000–1500 m above ground level (a.g.l.) due to the decreasing signal intensity with height that also depends on aerosol load. We have analyzed the differences and similarities in the diurnal evolution of the horizontal wind profiles for different seasons and their modelling with Weibull and von Mises probability distributions, finding a general trend of mean daytime wind from the NW with mean speeds around 3–4 m/s at low altitudes and 6–10 m/s at higher altitudes, and weaker mean nocturnal wind from the SE with similar height dependence. The highest speeds were observed during spring, and the lowest during winter. Finally, we studied the turbulent sources at the ABL with temporal (for each hour of the day) and height resolution. The results show a clear convective activity during daytime at altitudes increasing with time, and a significant wind-shear-driven turbulence during night-time
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