989 research outputs found

    From: George S. Benson

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    The Strange Plight of the Hungry Gulls

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    https://digitalcommons.acu.edu/crs_books/1539/thumbnail.jp

    A Critical Review of the Leadership Styles on the Performance of Public Secondary Schools In National Examinations In Tana River County, Kenya

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    In Kenya, many teachers have been elevated to leadership positions without much formal training leading to mismanagement of schools hence poor students’ performance and disappointing results. The kind of leadership style adopted by a leader greatly determines the nature of performance in national examinations. Experience in Kenya reveals that many schools that were once effective in academic performance have lowered their standards due to poor leadership while others have greatly improved through effective leadership. Whereas good leadership initiates and sustains a slow but steady upward spiral, ineffective leadership makes academic standards plummet. The purpose of this study was therefore to examine the impact of principals’ leadership style on the performance of students in public secondary schools in K.C.S.E. The researcher used an explanatory approach based on a descriptive analysis design to establish opinions and knowledge about the impact of principals ‘leadership style on students performance in Tana River County. The study targeted 9 secondary schools in the county that had presented candidates for the national examinations between 2005 & 2009. Both purposive and simple random sampling techniques were used to select a sample of 9 principals and 40 teachers respectively. From this a sample size of 49 respondents was selected for the study. Primary data was collected from the teachers and principals using self administered questionnaires based on the profile of leadership behavior and own behavior. Both inferential and descriptive statistics were used to analyze the data. ANOVA was used to establish the perception of teachers and their principals on leadership styles exhibited by the head teachers. Correlation analysis was used to show the relationship between principals’ leadership styles and student performance in national examinations. The finding of this study strongly indicate a positive relationship between the principals’ leadership styles and students’ performance. Autocratic leadership style was found to have a significant effect on the students’ performance in national examinations. The study recommends the principals to shift to transformative approaches of leadership to enhance good performance of at the national level. The study proposes mandatory leadership training programs for the secondary school principals to update them with modern leadership trends and techniques needed for effective performance

    Optical modeling of the Jefferson Laboratory IR demo FEL

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    The Thomas Jefferson National Accelerator Facility (Jefferson Lab) is in the process of building a 1 kW free-electron laser operates at 3 microns. The details of the accelerator driver are given in other papers in these proceedings. The optical cavity consists of a near-concentric resonator with transmissive outcoupling. Though several free-electron lasers have used similar designs, they have not had to confront the high average-power loading present in this laser. It is useful to know the limits of this type of optical cavity design. The optical system of the laser has been modeled using the commercial code GLAD{reg_sign} by using a Beer`s-law region to mimic the FEL interaction. The effects of mirror heating have been calculated and compared with analytical treatments. The magnitude of the distortion for several materials and wave-lengths has been estimated. The model developed here allows one to quickly determine whether the mirror substrates and coatings are adequate for operation at a given optical power level once the absorption of the coatings, substrate, and transmission are known. Results of calculations of the maximum power level expected using several different sets of mirrors will be presented. Measurements of the distortion in calcium fluoride from absorption of carbon dioxide laser light are planned to benchmark the simulations. Multimode simulations using the code ELIXER have been carried out to characterize the saturated optical mode quality. The results will be presented

    Recent Studies in Andean Prehistory and Protohistory: Papers from the Second Annual Northeast Conference on Andean Archaeology and Ethnohistory

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    The contributions in this volume represent nine of the twenty-three papers presented at the Second Annual Northeast Conference on Andean Archaeology and Ethnohistory (NCAAE) held at the American Museum of Natural History on November 19-20, 1983. Papers include The Preceramic and Formative Period Occupations in the Cordillera Negra: Preliminary Report by Michael A. Malpass, The Early Horizon--Early Intermediate Period Transition: A View from the Nepena and Viru Valleys by Richard E. Daggett, Paracas in Chincha and Pisco: A Reappraisal of the Ocucaje Sequence by Dwight T. Wallace, Impressions in Metal: Reconstructing Burial Context at Loma Negra, Peru by Anne-Louise Schaeffer, The Moche Moon by Elizabeth P. Benson, Archaeological Investigation in the Andean Piedmont and High Llanos of Western Venezuela: A Preliminary Report by Charles S. Spencer and Elsa M. Redmond, Pachacamac--An Andean Oracle Under Inca Rule by Thomas C. Patterson, The Spanish League and Inca Sites: A Reassessment of the Itinerary of Juan de Matienzo through N.W. Argentina by Gordon C. Pollard, and Written Sources on Andean Cosmogony by George Kubler.https://digitalcommons.library.umaine.edu/andean_past_special/1001/thumbnail.jp

    New Forearm Elements Discovered of Holotype Specimen Australovenator wintonensis from Winton, Queensland, Australia

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    New skeletal elements are reported of the holotype specimen Australovenator wintonensis, from the type locality, near Winton, central western Queensland. New elements include left and right humeri, right radius, right radiale, right distal carpal 1, near complete right metacarpal I, left manual phalanx II-1, left manual phalanx II-2, near complete left manual phalanx II-3 and a left manual phalanx III-3. These new elements combined with those previously described are compared against other neovenatorids

    Sustainability appraisal: Jack of all trades, master of none?

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    Sustainable development is a commonly quoted goal for decision making and supports a large number of other discourses. Sustainability appraisal has a stated goal of supporting decision making for sustainable development. We suggest that the inherent flexibility of sustainability appraisal facilitates outcomes that often do not adhere to the three goals enshrined in most definitions of sustainable development: economic growth, environmental protection and enhancement, and the wellbeing of the human population. Current practice is for sustainable development to be disenfranchised through the interpretation of sustainability, whereby the best alternative is good enough even when unsustainable. Practitioners must carefully and transparently review the frameworks applied during sustainability appraisal to ensure that outcomes will meet the three goals, rather than focusing on a discourse that emphasises one or more goals at the expense of the other(s)

    Extragalactic millimeter-wave point source catalog, number counts and statistics from 771 square degrees of the SPT-SZ Survey

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    We present a point source catalog from 771 square degrees of the South Pole Telescope Sunyaev Zel'dovich (SPT-SZ) survey at 95, 150, and 220 GHz. We detect 1545 sources above 4.5 sigma significance in at least one band. Based on their relative brightness between survey bands, we classify the sources into two populations, one dominated by synchrotron emission from active galactic nuclei, and one dominated by thermal emission from dust-enshrouded star-forming galaxies. We find 1238 synchrotron and 307 dusty sources. We cross-match all sources against external catalogs and find 189 unidentified synchrotron sources and 189 unidentified dusty sources. The dusty sources without counterparts are good candidates for high-redshift, strongly lensed submillimeter galaxies. We derive number counts for each population from 1 Jy down to roughly 9, 5, and 11 mJy at 95, 150, and 220 GHz. We compare these counts with galaxy population models and find that none of the models we consider for either population provide a good fit to the measured counts in all three bands. The disparities imply that these measurements will be an important input to the next generation of millimeter-wave extragalactic source population models.Comment: 23 pages, 8 figures, submitted to Ap

    Mass Calibration and Cosmological Analysis of the SPT-SZ Galaxy Cluster Sample Using Velocity Dispersion σv\sigma_v and X-ray YXY_\textrm{X} Measurements

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    We present a velocity dispersion-based mass calibration of the South Pole Telescope Sunyaev-Zel'dovich effect survey (SPT-SZ) galaxy cluster sample. Using a homogeneously selected sample of 100 cluster candidates from 720 deg2 of the survey along with 63 velocity dispersion (σv\sigma_v) and 16 X-ray Yx measurements of sample clusters, we simultaneously calibrate the mass-observable relation and constrain cosmological parameters. The calibrations using σv\sigma_v and Yx are consistent at the 0.6σ0.6\sigma level, with the σv\sigma_v calibration preferring ~16% higher masses. We use the full cluster dataset to measure σ8(Ωm/0.27)0.3=0.809±0.036\sigma_8(\Omega_ m/0.27)^{0.3}=0.809\pm0.036. The SPT cluster abundance is lower than preferred by either the WMAP9 or Planck+WMAP9 polarization (WP) data, but assuming the sum of the neutrino masses is ∑mν=0.06\sum m_\nu=0.06 eV, we find the datasets to be consistent at the 1.0σ\sigma level for WMAP9 and 1.5σ\sigma for Planck+WP. Allowing for larger ∑mν\sum m_\nu further reconciles the results. When we combine the cluster and Planck+WP datasets with BAO and SNIa, the preferred cluster masses are 1.9σ1.9\sigma higher than the Yx calibration and 0.8σ0.8\sigma higher than the σv\sigma_v calibration. Given the scale of these shifts (~44% and ~23% in mass, respectively), we execute a goodness of fit test; it reveals no tension, indicating that the best-fit model provides an adequate description of the data. Using the multi-probe dataset, we measure Ωm=0.299±0.009\Omega_ m=0.299\pm0.009 and σ8=0.829±0.011\sigma_8=0.829\pm0.011. Within a ν\nuCDM model we find ∑mν=0.148±0.081\sum m_\nu = 0.148\pm0.081 eV. We present a consistency test of the cosmic growth rate. Allowing both the growth index γ\gamma and the dark energy equation of state parameter ww to vary, we find γ=0.73±0.28\gamma=0.73\pm0.28 and w=−1.007±0.065w=-1.007\pm0.065, demonstrating that the expansion and the growth histories are consistent with a LCDM model (γ=0.55; w=−1\gamma=0.55; \,w=-1).Comment: Accepted by ApJ (v2 is accepted version); 17 pages, 6 figure

    A Measurement of the Cosmic Microwave Background Damping Tail from the 2500-square-degree SPT-SZ survey

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    We present a measurement of the cosmic microwave background (CMB) temperature power spectrum using data from the recently completed South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) survey. This measurement is made from observations of 2540 deg2^2 of sky with arcminute resolution at 150 150\,GHz, and improves upon previous measurements using the SPT by tripling the sky area. We report CMB temperature anisotropy power over the multipole range 650<ℓ<3000650<\ell<3000. We fit the SPT bandpowers, combined with the seven-year Wilkinson Microwave Anisotropy Probe (WMAP7) data, with a six-parameter LCDM cosmological model and find that the two datasets are consistent and well fit by the model. Adding SPT measurements significantly improves LCDM parameter constraints; in particular, the constraint on θs\theta_s tightens by a factor of 2.7. The impact of gravitational lensing is detected at 8.1 σ8.1\, \sigma, the most significant detection to date. This sensitivity of the SPT+WMAP7 data to lensing by large-scale structure at low redshifts allows us to constrain the mean curvature of the observable universe with CMB data alone to be Ωk=−0.003−0.018+0.014\Omega_k=-0.003^{+0.014}_{-0.018}. Using the SPT+WMAP7 data, we measure the spectral index of scalar fluctuations to be ns=0.9623±0.0097n_s=0.9623 \pm 0.0097 in the LCDM model, a 3.9 σ3.9\,\sigma preference for a scale-dependent spectrum with ns<1n_s<1. The SPT measurement of the CMB damping tail helps break the degeneracy that exists between the tensor-to-scalar ratio rr and nsn_s in large-scale CMB measurements, leading to an upper limit of r<0.18r<0.18 (95%,C.L.) in the LCDM+rr model. Adding low-redshift measurements of the Hubble constant (H0H_0) and the baryon acoustic oscillation (BAO) feature to the SPT+WMAP7 data leads to further improvements. The combination of SPT+WMAP7+H0H_0+BAO constrains ns=0.9538±0.0081n_s=0.9538 \pm 0.0081 in the LCDM model, a 5.7 σ5.7\,\sigma detection of ns<1n_s < 1, ... [abridged]Comment: 21 pages, 10 figures. Replaced with version accepted by ApJ. Data products are available at http://pole.uchicago.edu/public/data/story12
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