1,252 research outputs found

    Using IDI Guided Development to Increase Intercultural Competence

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    The qualitative case study examined Intercultural Development Inventory (IDI) pre-post test data and responses from a sample of preservice teachers. The study focused on the effect of the process of administering IDI Guided Development to increase the intercultural competence of preservice teachers. The study was based on the conceptual framework of the Intercultural Development Continuum (IDC), adapted from the Developmental Model of Intercultural Sensitivity originally proposed by Dr. Milton Bennett. In addition, intercultural competence models, theories, practices, and strategies were examined, including Deardorff’s Developing and Assessing Intercultural Competence Models, Kolb’s Experiential Learning Theory, Mezirow’s Transformative Learning Theory, Loden’s Dimensions of Diversity Wheel, and Weigl’s Cultural Self-Study. The findings of the study revealed how effective IDI Guided Development, a comprehensive five-step developmental process, combined with individualized coaching guidance by an IDI Qualified Administrator, produced impressive increases in intercultural competence development. Drawing on many educational theories and models, the study results demonstrated the importance of using a combination of a high-quality assessment tool, a transformative experiential learning process for change, measurable goals and outcomes, and a coach to facilitate the development of intercultural competence

    Theory of optical spectra of polar quantum wells: Temperature effects

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    Theoretical and numerical calculations of the optical absorption spectra of excitons interacting with longitudinal-optical phonons in quasi-2D polar semiconductors are presented. In II-VI semiconductor quantum wells, exciton binding energy can be tuned on- and off-resonance with the longitudinal-optical phonon energy by varying the quantum well width. A comprehensive picture of this tunning effect on the temperature-dependent exciton absorption spectrum is derived, using the exciton Green's function formalism at finite temperature. The effective exciton-phonon interaction is included in the Bethe-Salpeter equation. Numerical results are illustrated for ZnSe-based quantum wells. At low temperatures, both a single exciton peak as well as a continuum resonance state are found in the optical absorption spectra. By contrast, at high enough temperatures, a splitting of the exciton line due to the real phonon absorption processes is predicted. Possible previous experimental observations of this splitting are discussed.Comment: 10 pages, 9 figures, to appear in Phys. Rev. B. Permanent address: [email protected]

    Fine structure of excitons in Cu2_2O

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    Three experimental observations on 1s-excitons in Cu2_2O are not consistent with the picture of the exciton as a simple hydrogenic bound state: the energies of the 1s-excitons deviate from the Rydberg formula, the total exciton mass exceeds the sum of the electron and hole effective masses, and the triplet-state excitons lie above the singlet. Incorporating the band structure of the material, we calculate the corrections to this simple picture arising from the fact that the exciton Bohr radius is comparable to the lattice constant. By means of a self-consistent variational calculation of the total exciton mass as well as the ground-state energy of the singlet and the triplet-state excitons, we find excellent agreement with experiment.Comment: Revised abstract; 10 pages, revtex, 3 figures available from G. Kavoulakis, Physics Department, University of Illinois, Urban

    Laboratory Evaluation of Black Carbon Deposition onto Snow and Transport via Snowmelt

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    Black carbon (BC) is an aerosol material produced by incomplete combustion of fossil fuels and biomass. BC has been shown to be the second most important anthropogenic climate warming agent after carbon dioxide due to its ability to absorb solar radiation, influence cloud behavior, and accelerate snow melt. BC in otherwise clean snow can significantly reduce its reflectivity. In order to learn about the significance of BC contamination in snow, we explored the deposition of BC onto snow and the transport of BC in snow during snowmelt. A Single Particle Soot Photometer (SP2), was used to measure the concentration and size distribution of BC in an airstream drawn through snow to determine the rate at which the snow trapped BC. BC concentration in meltwater was measured to determine if the BC was left in the snow or was removed during melting. SP2 testing showed a significant drop in BC aerosol concentration after contact with the snow. This implies that naturally occurring snow is a highly efficient absorber of BC from the atmosphere. Meltwater samples had a lower BC concentration than the snow, suggesting that the majority of the BC is left behind in snow during partial melting. This accumulation of BC could potentially cause a positive feedback to the rate of snowmelt. Better understanding the behavior of BC in snow will help scientists describe the impact of BC on climate and help policymakers predict the benefits of reducing BC emissions

    Accounting Principles : A Business Perspective

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    1. Accounting and its use in business decisions2. Recording business transactions3. Adjustments for financial reporting4. Completing the accounting cycle5. Accounting theory6. Merchandising transactions7. Measuring and reporting inventories8. Control of cash9. Receivables and payables10. Property, plant, and equipment11. Plant asset disposals, natural resources, and intangible assets12. Stockholders' equity: Classes of capital stock13. Corporations: Paid-in capital, retained earnings, dividends, and treasury stock14. Stock investments15. Long-term financing: Bonds16. Analysis using the statement of cash flows17. Analysis and interpretation of financial statements18. Managerial accounting concepts/job costing19. Process: Cost systems20. Using accounting for quality and cost management21. Cost-volume-profit analysis22. Short-term decision making: Differential analysis23. Budgeting for planning and control24. Control through standard costs25. Responsibility accounting: Segmental analysis26. Capital budgeting:Long-range planningAccounting Principles: A Business Perspective is Volume 2 of Accounting Principles and is focused on Managerial Accounting

    On the determination of the Fermi surface in high-Tc superconductors by angle-resolved photoemission spectroscopy

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    We study the normal state electronic excitations probed by angle resolved photoemission spectroscopy (ARPES) in Bi2201 and Bi2212. Our main goal is to establish explicit criteria for determining the Fermi surface from ARPES data on strongly interacting systems where sharply defined quasiparticles do not exist and the dispersion is very weak in parts of the Brillouin zone. Additional complications arise from strong matrix element variations within the zone. We present detailed results as a function of incident photon energy, and show simple experimental tests to distinguish between an intensity drop due to matrix element effects and spectral weight loss due to a Fermi crossing. We reiterate the use of polarization selection rules in disentangling the effect of umklapps due to the BiO superlattice in Bi2212. We conclude that, despite all the complications, the Fermi surface can be determined unambiguously: it is a single large hole barrel centered about (pi,pi) in both materials.Comment: Expanded discussion of symmetrization method in Section 5, figures remain the sam

    Poly(amidoamine)-BSA conjugates synthesised by Michael addition reaction retained enzymatic activity

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    Polymer-protein conjugates are key to overcome some of the therapeutic protein limitations, including inefficient intracellular delivery. Poly(amidoamine)s are bioresponsive polyelectrolytes, which can form complexes with proteins and promote their delivery into the cytosol of cells. To investigate if conjugation would affect the activity of the protein, two poly(amidoamine)-BSA conjugates were synthesised using a “grafted to” method and Michael addition reaction. Following purification, the conjugates were characterised by electrophoresis, size exclusion chromatography (Mn(C1) = 140.7 kDa ; Mn(C2) = 218.6 kDa) and light scattering (Dh(C1) = 37.5 nm ; Dh(C2) = 75.1 nm). As a result of the conjugation with the cationic polymer, the conjugates had a positive zeta potential (?(C1) = +15.4 mV; ?(C2) = +20.2 mV). TNBS assays demonstrated that 16% to 25% of the protein amine groups were modified and HPLC analysis indicated that the amount of protein in the conjugate was 0.76 mg of BSA/mg of PAA (C1) and 0.43 mg of BSA /mg of PAA (C2). Enzymatic assays indicated the conjugates displayed an esterase activity similar (C1) or reduced ~ 35% (C2) compare to BSA. Altogether the results demonstrated that the conjugation of poly(amidoamine)s to a model protein can lead to the formation of bioconjugates that retain the enzymatic activity of the native protein. Such conjugates could have some application in protein delivery and enzyme engineering for biocatalysis and biosensors

    Controlled assembly of SNAP-PNA-fluorophore systems on DNA templates to produce fluorescence resonance energy transfer

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    The SNAP protein is a widely used self-labeling tag that can be used for tracking protein localization and trafficking in living systems. A model system providing controlled alignment of SNAP-tag units can provide a new way to study clustering of fusion proteins. In this work, fluorescent SNAP-PNA conjugates were controllably assembled on DNA frameworks forming dimers, trimers, and tetramers. Modification of peptide nucleic acid (PNA) with the O6-benzyl guanine (BG) group allowed the generation of site-selective covalent links between PNA and the SNAP protein. The modified BG-PNAs were labeled with fluorescent Atto dyes and subsequently chemo-selectively conjugated to SNAP protein. Efficient assembly into dimer and oligomer forms was verified via size exclusion chromatography (SEC), electrophoresis (SDS-PAGE), and fluorescence spectroscopy. DNA directed assembly of homo- and hetero-dimers of SNAP-PNA constructs induced homo- and hetero-FRET, respectively. Longer DNA scaffolds controllably aligned similar fluorescent SNAP-PNA constructs into higher oligomers exhibiting homo-FRET. The combined SEC and homo-FRET studies indicated the 1:1 and saturated assemblies of SNAP-PNA-fluorophore:DNA formed preferentially in this system. This suggested a kinetic/stoichiometric model of assembly rather than binomially distributed products. These BG-PNA-fluorophore building blocks allow facile introduction of fluorophores and/or assembly directing moieties onto any protein containing SNAP. Template directed assembly of PNA modified SNAP proteins may be used to investigate clustering behavior both with and without fluorescent labels which may find use in the study of assembly processes in cells

    Pb0.4Bi1.6Sr2Ca1Cu2O8+xPb_{0.4}Bi_{1.6}Sr_{2}Ca_{1}Cu_{2}O_{8+x} and Oxygen Stoichiometry: Structure, Resistivity, Fermi Surface Topology and Normal State Properties

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    Pb0.4Bi1.6Sr2CaCu2O8+xPb_{0.4}Bi_{1.6}Sr_2CaCu_2O_{8+x} (Bi(Pb)Bi(Pb)-2212) single crystal samples were studied using transmission electron microscopy (TEM), abab-plane (ρab\rho_{ab}) and cc-axis (ρc\rho_c) resistivity, and high resolution angle-resolved ultraviolet photoemission spectroscopy (ARUPS). TEM reveals that the modulation in the bb-axis for Pb(0.4)Pb(0.4)-doped Bi(Pb)Bi(Pb)-2212 is dominantly of PbPb-type that is not sensitive to the oxygen content of the system, and the system clearly shows a structure of orthorhombic symmetry. Oxygen annealed samples exhibit a much lower cc-axis resistivity and a resistivity minimum at 8013080-130K. He-annealed samples exhibit a much higher cc-axis resistivity and dρc/dT<0d\rho_c/dT<0 behavior below 300K. The Fermi surface (FS) of oxygen annealed Bi(Pb)Bi(Pb)-2212 mapped out by ARUPS has a pocket in the FS around the Mˉ\bar{M} point and exhibits orthorhombic symmetry. There are flat, parallel sections of the FS, about 60\% of the maximum possible along kx=kyk_x = k_y, and about 30\% along kx=kyk_x = - k_y. The wavevectors connecting the flat sections are about 0.72(π,π)0.72(\pi, \pi) along kx=kyk_x = k_y, and about 0.80(π,π)0.80(\pi, \pi) along kx=kyk_x = - k_y, rather than (π,π)(\pi,\pi). The symmetry of the near-Fermi-energy dispersing states in the normal state changes between oxygen-annealed and He-annealed samples.Comment: APS_REVTEX 3.0, 49 pages, including 11 figures, available upon request. Submitted to Phys. Rev. B
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