995 research outputs found

    Evolving perceptions of effective administration in secondary education

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    Educational leaders are faced with a variety of challenges. Effective administrators must be knowledgeable of the wide array of demands and have an innovative ability to manage them. The Master of Arts in Education courses along with personal experiences has helped me develop the beliefs, attitude, knowledge, and skills which I anticipate using in performance as an administrator. The curriculum has helped me formulate a personal vision of how my leadership style can make a positive difference in the lives of students. This reflective essay analyzes a variety of issues facing future administrators and communicates my vision of effective performance in an administrative role

    Long-term response of corn to limited irrigation and crop rotations

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    Dwindling water supplies for irrigation are prompting alternative management choices by irrigators. Limited irrigation, where less water is applied than full crop demand, may be a viable approach. Application of limited irrigation to corn was examined in this research. Corn was grown in crop rotations with dryland, limited irrigation, or full irrigation management from 1985 to 1999. Crop rotations included corn following corn (continuous corn), corn following wheat, followed by soybean (wheat-corn-soybean), and corn following soybean (corn-soybean). Full irrigation was managed to meet crop evapotranspiration requirements (ETc). Limited irrigation was managed with a seasonal target of no more than 150 mm applied. Precipitation patterns influenced the outcomes of measured parameters. Dryland yields had the most variation, while fully irrigated yields varied the least. Limited irrigation yields were 80% to 90% of fully irrigated yields, but the limited irrigation plots received about half the applied water. Grain yields were significantly different among irrigation treatments. Yields were not significantly different among rotation treatments for all years and water treatments. For soil water parameters, more statistical differences were detected among the water management treatments than among the crop rotation treatments. Economic projections of these management practices showed that full irrigation produced the most income if water was available. Limited irrigation increased income significantly from dryland management

    Irrigation management strategies for corn to conserve water

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    Presented at the Central Plains irrigation conference on February 17-18, 2004 in Kearney Nebraska.Includes bibliographical references

    Field scale limited irrigation scenarios for water policy strategies

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    ABSTRACT. Approaches to reducing irrigation inputs to crops have been studied for the past 50 to 60 years in research settings. Fewer efforts have been made to document limited irrigation responses over a number of seasons on commercial fields. This study compared farm−based irrigation management (FARM) with best management practices (BMP), late initiation of irrigation (LATE), and a restricted allocation (ALLOC). These irrigation management strategies each occupied 1/8 of a center pivot system in southwest Nebraska in continuous corn production, on four cooperating farms, which were replicated at the same sites for 3 to 6 years. Irrigation variables were achieved by irrigating or not irrigating, or by speeding up or slowing down the center pivot. When the grain yields and irrigation amounts were normalized each year using the FARM treatment as the basis, on average for three of four locations, the BMP treatment yielded equal to the FARM treatment, the LATE treatment yielded 93 % of the FARM treatment and the ALLOC yielded 84 % of the FARM treatment. At the same time, it took 76 % and 57 % of the water for the LATE and ALLOC treatments, respectively, to achieve these yields. The adjusted gross returns (yield price – irrigation treatment costs) of the irrigation treatments were analyzed for each location. When the gross returns were normalized using the FARM treatment as the basis, FARM and BMP returns were equal across combinations of high and low input commodity prices and pumping costs. The LATE treatment gross return was 95 % of FARM return. The gross return for the ALLOC treatment was 85 % to 91 % of the FARM treatment. The higher the water costs, the lower the difference between the highest and lowest returning water treatments. Relationships between evapotranspiratio

    Nitrate Leaching in Irrigated Corn and Soybean in a Semi-Arid Climate

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    Nitrate-nitrogen leached from the root zone of land in intensive corn production is a major groundwater contaminant in some of the intensively irrigated regions of the western Cornbelt, including central and western Nebraska. To obtain a clearer understanding of the amount and timing of nitrate leaching losses from irrigated crops, 14 monolithic percolation lysimeters were installed in 1989-1990 in sprinkler irrigated plots at the University of Nebraska’s West Central Research and Extension Center near North Platte, Nebraska. The lysimeters were used to provide a direct measure of leachate depth from continuous corn and a corn-soybean rotation. Both cropping systems were sprinkler irrigated and used current best management practices (BMPs) in the region for water and nitrogen management. Leachate was collected from 1990 through 1998 and analyzed for nitrate-N concentration. Results for the period 1993- 1998 are reported here. In the semi-arid climate of West-Central Nebraska, the interaction of rainfall patterns with the period of active uptake of water by crops played a major role in defining leaching patterns. Careful irrigation scheduling did not eliminate leaching during the growing season. There was no significant difference in drainage depth between continuous corn and the corn-soybean rotation. The average drainage depth among the lysimeters was 218 mm yr-1. This was more than expected, and in part resulted from above normal precipitation during several years of the study. No water quality benefit was found for the corn-soybean rotation as compared to continuous corn. Nitrate-N concentration in the leachate from continuous corn averaged 24 mg L-1, while that from the corn-soybean rotation averaged 42 mg L-1. Total yearly nitrate leaching loss averaged 52 kg ha-1 for continuous corn and 91 kg ha-1 for the rotation. This represents the equivalent of 27% and 105% of the amount of N fertilizer applied over the six years of study. In calculating N fertilizer needs for corn in Nebraska, the recommended legume N credit of 50 kg ha-1 for a preceding crop of soybean may be too low under irrigated production

    Color loci placemaking: The urban color between needs of continuity and renewal

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    The article presents the theoretical framework and the operational concepts of a research, finalized to explore and verify the prerequisites of an approach to urban color that, while recognizing to color the flexible as well as transient capacity to respond to the successive and multiple demands that characterize the urban space, sees a possible way of coexisting between the needs of continuity and renewal. Searching to understand the modalities and possibilities through which colour can intervene in the processes of transformation of the city to support both the needs of resignification and reappropriation and those of conservation and enhancement of the vital identity of each single place, the research looked on one side to the experiences gained within the colour plans and Lenclos' geography of colour and on the other side to the different and diversified experiences developed within the idea and practice of placemaking, aimed at the recognition and enhancement of the collective and plural creative dimension that colour seems effectively able to interpret. The term “color loci placemaking” was introduced to summarize this mode/possibility of understanding and approaching urban color, characterized especially by the attention for the specificity of each single place and the human factor underpinning place‐experience

    Probing the axion-nucleon coupling with the next generation of axion helioscopes

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    A finite axion–nucleon coupling, nearly unavoidable for QCD axions, leads to the production of axions via the thermal excitation and subsequent de-excitation of 57Fe isotopes in the sun. We revise the solar bound on this flux adopting the up to date emission rate, and investigate the sensitivity of the proposed International Axion Observatory IAXO and its intermediate stage BabyIAXO to detect these axions. We compare different realistic experimental options and discuss the model dependence of the signal. Already BabyIAXO has sensitivity far beyond previous solar axion searches via the nucleon coupling and IAXO can improve on this by more than an order of magnitude

    Measurement of the Luminosity in the ZEUS Experiment at HERA II

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    The luminosity in the ZEUS detector was measured using photons from electron bremsstrahlung. In 2001 the HERA collider was upgraded for operation at higher luminosity. At the same time the luminosity-measuring system of the ZEUS experiment was modified to tackle the expected higher photon rate and synchrotron radiation. The existing lead-scintillator calorimeter was equipped with radiation hard scintillator tiles and shielded against synchrotron radiation. In addition, a magnetic spectrometer was installed to measure the luminosity independently using photons converted in the beam-pipe exit window. The redundancy provided a reliable and robust luminosity determination with a systematic uncertainty of 1.7%. The experimental setup, the techniques used for luminosity determination and the estimate of the systematic uncertainty are reported.Comment: 25 pages, 11 figure

    Can serious games help to mitigate climate change? Exploring their influence on Spanish and American teenagers’ attitudes

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    Es urgente y necesario reducir las emisiones de gases de efecto invernadero y mitigar el cambio climático, y esta lucha requiere un cambio en las actitudes de los adolescentes. En la búsqueda de nuevos enfoques dirigidos a los jóvenes, los serious games en formato online parecen una prometedora herramienta de comunicación y educación. Basándonos en el juego 2020 Energy como estudio de caso, el principal objetivo de este artículo es examinar la influencia de dicho juego sobre las actitudes de adolescentes españoles y estadounidenses (N = 108), empleando un diseño pretest-posttest con una condición experimental (jugar al juego) y una condición de control (no jugar al juego). Los resultados muestran que no había diferencias estadísticamente significativas después de jugar al juego, aunque una observación más detallada de cada factor ofrece algunas consecuencias positivas.There is an urgent need to curb emissions and mitigate climate change, and this fight requires a change in teenagers’ attitudes. In search of new approaches targeting youth, online games are seen as a promising tool for communication and education. Using the serious game 2020 Energy as a case study, the main objective of this paper is to examine the influence of the game on Spanish and American teenagers’ attitudes (N = 108), employing a pretest-posttest design with an experimental condition (playing the game) and a control condition (not playing the game). Results show that there have not been statistically significant differences after playing the game, although when looking closer at each factor, some positive consequences can be found.HUM466 Acceso y evaluación de la información científic

    Molecular Mechanism of Capacitative Calcium Entry Deficits in Familial Alzheimer’s Disease

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    Poster PresentationPresenilin (PS) is the catalytic subunit of the gamma-secretase which is responsible for the cleavage of amyloid precursor protein to form beta amyloid (Aβ). Mutations in PS associated with familial Alzheimer’s disease (FAD) increase the Aβ plaques formation in the brain and cause neurodegeneration. Apart from this, FAD-linked PS mutations have been demonstrated to disrupt intracellular calcium (Ca2+) regulation. Accumulating evidence suggests that Ca2+ disruption may play a proximal role in the AD pathogenesis. Mutant PS exaggerated Ca2+ release from the endoplasmic reticulum (ER). It also attenuated Ca2+ entry through the capacitative Ca2+ entry (CCE) pathway, yet, the mechanism is not fully understood. Using a human neuroblast cell line SH-SY5Y and Ca2+ imaging technique, we observed CCE deficits in FAD-linked PS1-M146L retroviral infected cell. The attenuation of CCE in PS1 mutant cells was not mediated by the down-regulation of STIM1 and Orai1 expression, the known essential molecular players in the CCE pathway. Instead, we identified a molecular interaction between PS and STIM1 proteins by immunoprecipitation. On the other hand, immunofluorescence staining showed a significant reduction in puncta formation after ER Ca2+ depleted by thapsigargin in cells infected with PS1-M146L as compared to the wild type PS1 infected cells. Taken together, our results suggest a molecular mechanism for the CCE deficits in FAD associated with PS1 mutations. The interaction of mutant PS1 with STIM1 exerts a negative impact on its oligomerization and/or its interaction with Orai1. Our results may suggest molecular targets for the development of therapeutic agents that help to treat the disease.published_or_final_versio
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