A study of educational leadership preparation concerning the assistant principal : perspectives of Missouri principals and assistant principals

Abstract from short.pdf file.Dissertation supervisor: Dr. Cynthia MacGregor.Includes vita.It is unclear if the initial preparation of educational leaders, in relation to the role of assistant principals (APs), has kept pace with growing demands associated with the position. Little research exists specifically addressing the initial developmental preparation of APs. Elements of a needs assessment and program evaluation combine to build infrastructure for a conceptual framework to guide this study. A mixed method design for this study was determined to be the best method in which to provide answers concerning the proposed research questions. Participants consisted of lead and assistant principals from school districts across Missouri. Quantitative and qualitative data was analyzed for trends. Quantitative and qualitative data was compared to one another in order to attain a thorough and comprehensive examination of collected data.Includes bibliographical references (pages 149-161)

Number and Size Distribution of Airborne Nanoparticles during Summertime in Kuwait: First Observations from the Middle East

We made fast response measurements of size-resolved particle number concentrations (PNCs) and distributions (PNDs) in the 5–1000 nm range close to a busy roadside, continuously for 31 days, in Kuwait. The aims were to understand their dispersion characteristics during summertime and dust events, and association with trace pollutants (NO_<i>x</i>, O₃, CO, SO₂, and PM₁₀) and meteorological parameters. PNCs were found up to ∼19-times higher (5.98 × 10⁵ cm^–3) than those typically found in European roadside environments. Size distributions exhibited over 90% of PNCs in ultrafine size range (<100 nm) and a negligible fraction over 300 nm. Peak PNDs appeared at ∼12 nm, showing an unusually large peak in nucleation mode. Diurnal variations of PNCs coincided with the cyclic variations in CO, NO_<i>x</i>, and traffic volume during morning and evening rush hours. Despite high traffic volume, PNC peaks were missing during noon hours due to high ambient temperature (∼48 °C) that showed an inverse relationship with the PNCs. Principal Component Analysis revealed three probable sources in the arealocal road traffic, fugitive dust, and refineries. Dust events, categorized by PM₁₀ with over 1000 μg m^–3, decreased PNCs by ∼25% and increased their geometric mean diameters (GMDs) by ∼66% compared with nondust periods

Enhanced Resonance Energy Transfer and White-Light Emission from Organic Fluorophores and Lanthanides in Dendron-based Hybrid Hydrogel

In this paper, we have investigated the use of poly­(aryl ether) dendron-based gel as a medium for resonance energy transfer (RET) from organic donors (phenanthrene, naphthalene, and pyrene) to lanthanide [Eu­(III) and Tb­(III)] ions. The gel has been prepared through self-assembly of glucose-cored poly­(aryl ether) dendrons in a dimethyl sulfoxide/water mixture (1:9 v/v). The efficiency of RET was calculated by metal-centered emission quantum yield measurements in the gel medium. While there was no resonance energy transfer observed between the donor–acceptor pairs in solution, efficient RET has been observed in the gel medium. The metal-centered quantum yield values were 11.9% for phenanthrene–Eu­(III), 3.9% for naphthalene–Eu­(III), and 3.6% for pyrene–Eu­(III) systems. Partial RET in the system has been utilized to generate white-light emission from the gel by incorporating an additional lanthanide ion, Tb­(III), along with the organic donors and Eu­(III). The CIE (Commission Internationale d’Eclairage) coordinates obtained for gels formed by phenanthrene–Tb­(III)–Eu­(III) (PTE), naphthalene–Tb­(III)–Eu­(III) (NTE), and pyrene–Tb­(III)–Eu­(III) (PyTE) were (0.33, 0.32) for PTE, (0.35, 0.37) for NTE, and (0.35, 0.33) for PyTE. The correlated color temperatures (CCT) for white-light-emitting gels were calculated, and the values (5520 K for PTE, 4886 K for NTE, and 4722 K for PyTE) suggest that the system generates cool white light

Solvent-Mediated Room Temperature Synthesis of Highly Crystalline Cu₉S₅ (Cu_1.8S), CuSe, PbS, and PbSe from Their Elements

Highly crystalline Cu₉S₅ (Cu_1.8S), CuSe, PbS, and PbSe are obtained by reacting the elements in 2-mercaptoethanol as the solvent for 24 h at room temperature. The elemental reactions of copper and lead with sulfur in ethylene glycol were successful, yielding CuS and PbS, respectively. Metal sulfide formation was not observed using dimercaptoethane

Preliminary Estimates of Nanoparticle Number Emissions from Road Vehicles in Megacity Delhi and Associated Health Impacts

Rapid urbanisation in developing megacities like Delhi has resulted in an increased number of road vehicles and hence total particle number (ToN) emissions. For the first time, this study presents preliminary estimates of ToN emissions from road vehicles, roadside and ambient ToN concentrations, and exposure related excess deaths in Delhi in current and two future scenarios; business as usual (BAU) and best estimate scenario (BES). Annual ToN emissions are estimated as 1.37 × 10²⁵ for 2010 which are expected to increase by ∼4 times in 2030-BAU, but to decrease by ∼18 times in 2030-BES. Such reduction is anticipated due to a larger number of compressed natural gas driven vehicles and assumed retrofitting of diesel particulate filters to all diesel vehicles by 2020. Heavy duty vehicles emit the majority (∼65%) of ToN for only ∼4% of total vehicle kilometres traveled in 2010. Their contribution remains dominant under both scenarios in 2030, clearly requiring major mitigation efforts. Roadside and ambient ToN concentrations were up to a factor of 30 and 3 higher to those found in respective European environments. Exposure to ambient ToN concentrations resulted in ∼508, 1888, and 31 deaths per million people in 2010, 2030-BAU and 2030-BES, respectively

Assessing the Suitability of Multiple Dispersion and Land Use Regression Models for Urban Traffic-Related Ultrafine Particles

Comparative evaluations are needed to assess the suitability of near-road air pollution models for traffic-related ultrafine particle number concentration (PNC). Our goal was to evaluate the ability of dispersion (CALINE4, AERMOD, R-LINE, and QUIC) and regression models to predict PNC in a residential neighborhood (Somerville) and an urban center (Chinatown) near highways in and near Boston, Massachusetts. PNC was measured in each area, and models were compared to each other and measurements for hot (>18 °C) and cold (<10 °C) hours with wind directions parallel to and perpendicular downwind from highways. In Somerville, correlation and error statistics were typically acceptable, and all models predicted concentration gradients extending ∼100 m from the highway. In contrast, in Chinatown, PNC trends differed among models, and predictions were poorly correlated with measurements likely due to effects of street canyons and nonhighway particle sources. Our results demonstrate the importance of selecting PNC models that align with study area characteristics (e.g., dominant sources and building geometry). We applied widely available models to typical urban study areas; therefore, our results should be generalizable to models of hourly averaged PNC in similar urban areas

Quantum Confinement Effects in Organic Lead Tribromide Perovskite Nanoparticles

The optical and electronic properties of nanoparticles/nanocrystals (NC) of methylammonium lead tribromide perovskite (MAPbBr₃) have been studied in detail. We observe the effect of quantum confinement in particles of an average diameter of ∼6 nm and smaller, in the form of an increase in excitonic nature with decrease in particle size. The differences in the photophysical properties in bulk and NC forms of MAPbBr₃ are clearly observed in the temperature dependent measurements, and provide insight into the length scales prevalent in this system. We demonstrate devices consisting of active layers of NC in conjunction with low band gap polymer semiconductors which exhibit the dual functionality of a light emitting diode in the forward bias and a photodetector in the reverse bias.graphic

Protonated nucleobases are not fully ionized and may form stable base pairs in the crystalline state

The following paper presents experimental charge density studies of cytosinium chloride, adeninium chloride hemihydrate, and guanine dichloride crystals based on ultra-high resolution X-ray diffraction data and extensive theoretical calculations. Results confirm that the cohesive energies of the studied systems are dominated by contributions from intermolecular electrostatic interactions, as expected for ionic crystals. Electrostatic interactions energies (Ees) usually constitute 95% of total interaction energies. The Ees energies were several times larger in absolute value when compared, for example, to pairs of neutral nucleobases. However, they were not as big as some of the theoretical calculations predicted. This was because the molecules appeared not to be fully ionized in the studied crystals. Apart from chlorine to protonated nucleobase charge transfer, small but visible, charge redistribution within nucleobase cations was observed. Some pairs of single protonated bases in the studied crystals exhibited attractive interactions (negative values of Ees) or unusually low repulsion despite identical molecular charges. This was because strong hydrogen bonding between bases overcompensated overall cation-cation repulsion, the latter being weakened due to charge transfer and molecular charge density polarization

Managing buyer experience in a buyer–supplier relationship in MSMEs and SMEs

Monitoring buyer experience provides competitive advantages for suppliers as buyers explore the market before reaching a salesperson. Still, not many B2B suppliers monitor their buyers’ expectations throughout their procurement journey, especially in MSMEs and SMEs. In addition, the inductive research on evaluating buyer experience in buyer–supplier relationships is minimal, leaving an unexplored research area. This study explores antecedents of buyer experience during the buyer–supplier relationship in MSMEs and SMEs. Further, we investigate the nature of the influence of extracted precursors on the buyer experience. Firstly, we obtain the possible antecedents from the literature on buyer–supplier experience and supplier selection criteria. We also establish hypotheses based on transaction cost theory, resource-based view (RBV), and information processing view. Secondly, we employ an investigation based on the social media analytics-based approach to uncover the antecedents of buyer experience and their nature of influence on MSMEs and SME suppliers. We found that buyer experience is influenced by sustainable orientation, management capabilities (such as crisis management and process innovation), and suppliers’ technology capabilities (digital readiness, big data analytical capability).Other Information Published in: Annals of Operations Research License: https://creativecommons.org/licenses/by/4.0See article on publisher's website: http://dx.doi.org/10.1007/s10479-022-04954-3</p

Deoxycholate-Enhanced <i>Shigella</i> Virulence Is Regulated by a Rare π‑Helix in the Type Three Secretion System Tip Protein IpaD

Type three secretion systems (T3SS) are specialized nanomachines that support infection by injecting bacterial proteins directly into host cells. The <i>Shigella</i> T3SS has uniquely evolved to sense environmental levels of the bile salt deoxycholate (DOC) and upregulate virulence in response to DOC. In this study, we describe a rare <i>i</i> + 5 hydrogen bonding secondary structure element (π-helix) within the type three secretion system tip protein IpaD that plays a critical role in DOC-enhanced virulence. Specifically, engineered mutations within the π-helix altered the pathogen’s response to DOC, with one mutant construct in particular exhibiting an unprecedented reduction in virulence following DOC exposure. Fluorescence polarization binding assays showed that these altered DOC responses are not the result of differences in affinity between IpaD and DOC, but rather differences in the DOC-dependent T3SS tip maturation resulting from binding of IpaD to translocator/effector protein IpaB. Together, these findings begin to uncover the complex mechanism of DOC-enhanced <i>Shigella</i> virulence while identifying an uncommon structural element that may provide a much needed target for non-antibiotic treatment of <i>Shigella</i> infection