17,033 research outputs found

    Inverse photoemission in strongly correlated electron systems

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    Based on exact results for small clusters of 2D t-J model we demonstrate the existence of several distinct `channels' in its inverse photoemission (IPES) spectrum. Hole-like quasiparticles can either be annihilated completely, or leave behind a variable number of spin excitations, which formed the `dressing cloud' of the annihilated hole. In the physical parameter regime the latter processes carry the bulk of IPES weight and although the Fermi surface takes the form of hole pockets, the distribution of spectal weight including these `magnon-bands' in the IPES spectrum is reminiscent of free electrons. The emerging scenario for Fermiology and spectral weight distribution is shown to be consistent with photoemission, inverse photemission and de Haas--van Alphen experiments on cuprate superconductors.Comment: Revtex file, 4 PRB pages + three figures appended as uu-encoded postscript. Hardcopies of figures (or the entire manuscript) can also be obtained by e-mail request to: [email protected]

    EFFECT OF ROLE CLARITY ON JOB PERFORMANCE OF INSTRUCTORS PHYSICAL EDUCATION (IPES) OF SOUTHERN DISTRICT OF KHYBER PAKHTUNKHWA

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    Purpose: The purpose of this study was to examine the effect of Role Clarity (RC) on the Job Performance (JP) of Instructor Physical Education (IPEs) working in higher secondary schools of Khyber Pakhtunkhwa. Methods: The study was conducted in southern Districts of Khyber Pakhtunkhwa (LakkiMarwat, Bannu, D.I.khan and Tank). There are 141 (89 male and 52 female) IPEs working in different Higher Secondary Schools (Educational Management Information System [EMIS], 2019). A sample of 141 IEPs was chosen using the stratified sampling method. The survey research design was applied for this paper. A questionnaire was used based on the Five Point Likert scale for data collection. The validation of the data collection tool was done through index of Item Objective Congruence (IOC) whereas the reliability score was estimated (RC=0.861, JP=0.872) through Cronbach’s Alpha. Pearson Product Movement Correlation, Linear Regression, and Independent sample t-test were used as inferential statistics.  Results: The result of the study shows that there is a positive relationship between Role clarity and Job performance. The study concluded that the job performance of IPEs determined through how IPEs clear about their job. If IPEs have a clear vision about their job then it can make a significant contribution to their job performance. More precisely, higher role clarity leads to higher job performance. The result also indicates that there is a significant difference in the male and female IPEs Performance. Conclusion: The study concluded that male IPEs perform well as compared to female IPEs in terms of subject matter knowledge, assessment strategies, and communication skills

    Charge transport across metal/molecular (alkyl) monolayer-Si junctions is dominated by the LUMO level

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    We compare the charge transport characteristics of heavy doped p- and n-Si-alkyl chain/Hg junctions. Photoelectron spectroscopy (UPS, IPES and XPS) results for the molecule-Si band alignment at equilibrium show the Fermi level to LUMO energy difference to be much smaller than the corresponding Fermi level to HOMO one. This result supports the conclusion we reach, based on negative differential resistance in an analogous semiconductor-inorganic insulator/metal junction, that for both p- and n-type junctions the energy difference between the Fermi level and LUMO, i.e., electron tunneling, controls charge transport. The Fermi level-LUMO energy difference, experimentally determined by IPES, agrees with the non-resonant tunneling barrier height deduced from the exponential length-attenuation of the current

    ‘Food from Nowhere’: Food, Fuel and the Fantastical

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    UMA ANÁLISE DO PROCESSO DE GESTÃO DA EDUCAÇÃO A DISTÂNCIA EM UMA UNIVERSIDADE PÚBLICA DA REGIÃO SUDESTE

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    Este trabalho tem como objetivo analisar os processos de gestão da educação a distância (EaD) em instituições públicas de ensino superior (IPES). O trabalho se baseia em um estudo de caso em uma IPES. Os dados foram coletados por meio de entrevistas semi-estruturadas e pesquisa documental. Foi possível observar que o surgimento da EaD na IPES estudada apresentou características bastante específicas. Até o advento da Universidade Aberta do Brasil (UAB), a EaD sequer constava no Plano de Desenvolvimento Institucional (PDI) da IPES. Constatou-se que a IPES estudada não tem de fato políticas bem definidas para a EaD. Ela ainda depende muito das iniciativas isoladas de alguns poucos docentes. A EAD não está consolidada na instituição e não há de fato interesse da sua alta gestão em expandir as ações. A estrutura administrativa e acadêmica é muito rígida e dificulta o desenvolvimento das ações de EaD, em especial em termos de prazos para aprovações de projetos e relatórios. Editais da UAB têm sido abertos recentemente e projetos não têm sido enviados. O setor de apoio à EaD da instituição atua satisfatoriamente como suporte administrativo para os cursos a distância em funcionamento

    A GESTÃO ESTRATÉGICA NAS INSTITUIÇÕES PÚBLICAS DE ENSINO SUPERIOR

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    Este trabalho aborda a gestão estratégica nas Instituições Públicas de Ensino Superior (IPES), que assumem um grande desafio que é desenvolver estratégias capazes de atender às demandas externas, promovendo a melhoria da qualidade do ensino diante dos diversos ambientes competitivos. O objetivo deste artigo é analisar a gestão estratégica das IPES, sendo esta a responsável pelo diagnóstico dos problemas e proposições de políticas relacionadas ao ensino superior, enfatizando as metodologias da estratégia e da gestão estratégica que podem ser utilizadas em qualquer Instituição de Ensino Superior (IES) no âmbito da Administração Pública. A metodologia utilizada reporta-se a uma pesquisa bibliográfica sobre a gestão estratégica nas IPES, através de livros, artigos científicos e demais publicações. Conclui-se, então, que a gestão estratégica nas IPES poderá proporcionar um processo de gestão eficiente e de qualidade capaz de lidar com as constantes mudanças, disponibilizando aos gestores a melhor forma para tomada de decisões estratégicas

    Ion Bombardment of Ni(110) Studied with Inverse Photoemission Spectroscopy and Low-Energy Electron Diffraction

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    Inverse photoemission spectroscopy (IPES) performed on clean Ni(110) reveals an unoccupied electronic surface state with energy ~ 2.5 eV above the Fermi level for emission near the Ȳ point of the Surface Brillouin Zone. Ion bombardment of the sample creates defects that reduce the intensity of the peak in IPES spectra. Sharp, intense diffraction spots in low-energy electron diffraction (LEED) patterns taken of the clean surface become dimmer after bombardment. Results of these measurements are compared to Monte Carlo simulations of the sputtering process to ascertain the approximate size of clean patches on the sample necessary to sustain the IPES and LEED features. At 170 K, the IPES surface state peak appears closely associated with the population of surface atomic sites contained in clean circular patches of about 50 atoms. The LEED patterns persist to greater degrees of sputtering and are associated with smaller clean patches. Both measurements performed at 300 K indicate significant self-annealing of the sputtering damage

    An analysis of photoemission and inverse photoemission spectra of Si(111) and sulphur-passivated InP(001) surfaces

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    Photoemission (PES) and inverse-photoemission spectra (IPES) for the sulphur-passivated InP(001) surface are compared with theoretical predictions based on density-functional calculations. As a test case for our methods, we also present a corresponding study of the better known Si(111) surface. The reported spectra for InP(001)-S agree well with the calculated ones if the surface is assumed to consist of a mixture of two phases, namely, the fully S-covered (2×2)(2\times2)-reconstructed structure, which contains four S atoms in the surface unit-cell, and a (2×2)(2\times2) structure containing two S and two P atoms per unit cell. The latter has recently been identified in total-energy calculations as well as in core-level spectra of S-passivated Si(111)-(2×1)(2\times1) is in excellent agreement with the calculations. The comparison of the experimental-PES with our calculations provides additional considerations regarding the nature of the sample surface. It is also found that the commonly-used density-of-states approximation to the photo- and inverse- photoemission spectra is not valid for these systems.Comment: Submitted to Phys. Rev. B; 6 postscript formatted pages; 7 figures in gif format; postscript figures available upon reques
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