Hot Spots and Pseudogaps for Hole- and Electron-Doped High-Temperature Superconductors

Using cluster perturbation theory, it is shown that the spectral weight and pseudogap observed at the Fermi energy in recent Angle Resolved Photoemission Spectroscopy (ARPES) of both electron and hole-doped high-temperature superconductors find their natural explanation within the t-t'-t''-U Hubbard model in two dimensions. The value of the interaction U needed to explain the experiments for electron-doped systems at optimal doping is in the weak to intermediate coupling regime where the t-J model is inappropriate. At strong coupling, short-range correlations suffice to create a pseudogap but at weak coupling long correlation lengths associated with the antiferromagnetic wave vector are necessary.Comment: RevTeX 4, 4 pages, 5 figures (2 in color

Field Identification in Non-Unitary Diagonal Cosets

We study the nonunitary diagonal cosets constructed from admissible representations of Kac-Moody algebras at fractional level, with an emphasis on the question of field identification. Generic classes of field identifications are obtained from the analysis of the modular S matrix. These include the usual class related to outer automorphisms, as well as some intrinsically nonunitary field identifications. They allow for a simple choice of coset field representatives where all field components of the coset are associated with integrable finite weights.Comment: 34 page

Strong-Coupling Perturbation Theory of the Hubbard Model

The strong-coupling perturbation theory of the Hubbard model is presented and carried out to order (t/U)^5 for the one-particle Green function in arbitrary dimension. The spectral weight A(k,omega) is expressed as a Jacobi continued fraction and compared with new Monte-Carlo data of the one-dimensional, half-filled Hubbard model. Different regimes (insulator, conductor and short-range antiferromagnet) are identified in the temperature--hopping integral (T,t) plane. This work completes a first paper on the subject (Phys. Rev. Lett. 80, 5389 (1998)) by providing details on diagrammatic rules and higher-order results. In addition, the non half-filled case, infinite resummations of diagrams and the double occupancy are discussed. Various tests of the method are also presented.Comment: 28 pages, 19 figure

Using Social Emotional Data for School Improvement: A Case Study of Goochland County\u27s Use of the Gallup Student Poll

This case study presents a profile of a school division, Goochland County Public Schools in Virginia, that has not only recognized the value of measuring student social emotional development, but has become a regional leader in the effective use of student social emotional measures for guiding practice as well as broader school improvement processes. The case study, which focuses on Goochland County\u27s use of data from the Gallup Student Poll (GSP) over the past several years, is based on a series of interviews with principals and school leaders conducted during the spring of 2015. The case study includes an overview of the GSP, information about the initiation of the GSP in Goochland county,and then explores how this survey has impacted the county\u27s work with students, how it has supported their 2014-2020 strategic plan, and what future directions they see for use of this data. The purpose of this case study is to share Goochland\u27s story as a way of exploring how social emotional measures can be used in meaningful ways to impact educational processes and ultimately student learning and success

Capturing the Social/Emotional World of Students

The goal of this report is to explore the possibilities using student social emotional measures withing K-12 schools. This will include (1) a discussion of what constitutes a social emotional measure, (2) an overview of commonly used measures, and (3) a discussion of how these measures may inform school improvement processes and promote the success of students at the classroom, school, school system, and community level

Contexts of Cultural Diversity Professional Development in Schools

This report is part of a larger MERC study on Professional Development for Success in Culturally Diverse Schools.The goals of the larger study are (1) to understand the landscape of diversity within the schools in the MERC region, (2) to consider the implications for school policy and professional practice, (3) to review the current models of professional development that support teachers and other school professionals in regards to issues of cultural diversity, and (4) to develop and test models of professional development that have positive impacts on teacher practice, student outcomes and overall school success. With these goals in mind, this report contains three parts. Part 1 discusses demographic changes in the MERC region and provides historical, political, social, and economic contexts for understanding these changes. Part 2 describes the federal, state, and local policy contexts relevant to cultural diversity within schools, and professional development (PD) related to this topic. This section also reviews research on how policy contexts shape teachers’ decisions to participate in PD. Part 3 reviews existing studies of cultural diversity PD and describes the types of PD programs currently available in the MERC region. In the conclusion to the report, we present a list of recommendations for policy and and for future development and implementation of PD related to cultural diversity. The final section of the report also describes gaps in the existing body of knowledge and the research needed to better understand PD related to cultural diversity

Understanding Racial Inequity in School Discipline Across the Richmond Region

This report comes from the MERC Achieving Racial Equity in School Disciplinary Policies and Practices study. Launched in the spring of 2015, the purpose of this mixed- method study was to understand the factors related to disproportionate school discipline outcomes in MERC division schools. The study had two phases. Phase one (quantitative) used primary and secondary data to explore racial disparities in school discipline in the MERC region as well as discipline programs schools use to address them. Phase two (qualitative) explored the implementation of discipline programs in three MERC region schools, as well as educator and student perceptions of school discipline and racial disproportionality. This report shares findings from both phases of our study and offers numerous implications and recommendations for research, policy, and practice

Cultural Diversity Professional Development in Schools Survey

This report presents findings from the Metropolitan Educational Research Consortium (MERC) Cultural Diversity Within Schools Survey. This survey was designed for school- based professionals (i.e., teachers, instructional staff, administrators) within the MERC region. Administered in the fall of 2018, the survey collected information about experiences of professional development related to cultural diversity, attitudes toward cultural diversity within schools, perceptions of barriers and opportunities, and perspectives on the need for professional development. Section 1 of the report discusses the context for this survey effort: increased cultural diversity in our schools, increased cultural mismatch between students and teachers, and multicultural education as a promising practice. This is followed in section 2 with information about the survey development and administration process. In section 3, we present the findings from the survey in several subsections that explore group comparisons and results related to the different topics covered in the survey. In section 4, we share recommendations for policy, practice and future scholarship. These recommendations are informed by the relevant literature as well as the results of the survey. The report also includes two appendices: Appendix A presents a full version of the survey, Appendix B provides detailed tables of survey results disaggregated by school division. A third appendix, Appendix C provides technical information about the survey methodology, and is available online