3,993 research outputs found
Interacting Electrons on a Square Fermi Surface
Electronic states near a square Fermi surface are mapped onto quantum chains.
Using boson-fermion duality on the chains, the bosonic part of the interaction
is isolated and diagonalized. These interactions destroy Fermi liquid behavior.
Non-boson interactions are also generated by this mapping, and give rise to a
new perturbation theory about the boson problem. A case with strong repulsions
between parallel faces is studied and solved. There is spin-charge separation
and the square Fermi surface remains square under doping. At half-filling,
there is a charge gap and insulating behavior together with gapless spin
excitations. This mapping appears to be a general tool for understanding the
properties of interacting electrons on a square Fermi surface.Comment: 25 pages, Nordita preprint 94/22
Energy dependent Schrödinger operators and complex Hamiltonian systems on Riemann surfaces
We use so-called energy-dependent Schrödinger operators to establish a link between special classes of solutions on N-component systems of evolution equations and finite dimensional Hamiltonian systems on the moduli spaces of Riemann surfaces. We also investigate the phase-space geometry of these Hamiltonian systems and introduce deformations of the level sets associated to conserved quantities, which results in a new class of solutions with monodromy for N-component systems of PDEs.
After constructing a variety of mechanical systems related to the spatial flows of nonlinear evolution equations, we investigate their semiclassical limits. In particular, we obtain semicalssical asymptotics for the Bloch eigenfunctions of the energy dependent Schrödinger operators, which is of importance in investigating zero-dispersion limits of N-component systems of PDEs
Effects of Electrical Stimulation on Wound Closure in Mice with Experimental Diabetes Mellitus
The purpose of the present study was to examine the effect of electrical stimulation (ES) on the closure of full-thickness excisional wounds in mice with type-1 experimental diabetes mellitus (DM). Alloxon monohydrate (100mg/kg) was used to induce experimental DM in mole CD-1 mice (n = 88). Full-thickness skin excisions (1cm2) in diabetic (urine glucose \u3e 0) and non-diabetic (urine glucose = 0) mice were administered 1, 3, or 5 treatments of ES (200μs, 200 Hz) for 15 minutes, at 0 (sham), 5, 10, or 12.5 volts. Alloxon injection resulted in a positive urine glucose test in 48 mice yielding an induction rate for DM of 54.5 percent. All groups exhibited decreases in wound length, perimeter, and surface area between days 2 and 16 following the creation of wounds. Non-diabetic wounds treated with ES hod the greatest percentage (60%) of closure. Diabetic wounds treated with ES hod a greater percentage of closure (36%) compared with sham-treated diabetic animals (12.5%). Treatment of wounds with the highest voltage of ES (12.5V) produced significant (P \u3c 0.01) decreases in the surface area, and significant (P \u3c 0.01) changes in the shapes of wounds in both diabetic and non-diabetic animals compared with sham-treated animals. These results support the clinical use of this adjunctive therapy to accelerate the closure of ulcers due to OM
Validation of External Organizational Justice Assessment Through Replication, and Examination of Extraversion, Core Self-Evaluations, and Self-Monitoring as Moderators of the Relationship Between External Organizational Justice and Organizational Outcomes: A Two-Part Dissertation
In the first portion of this two-part dissertation, I attempted to replicate the findings published in Toaddy (2012), illustrating the relationships between External Organizational Justice (EJ) and a collection of organizational outcomes. In the second portion, I examined how the variables of Extraversion, Core Self-Evaluations (CSE), and Self-Monitoring (SM) moderate the relationships that were established in Toaddy (2012). The implications of this research attempted to illustrate the role that self-assessed personality factors can play in explaining and predicting the behavior of employees due to their perceptions of moral/immoral behaviors of their employers toward external entities. Cases that illustrate the importance of this research can be made out of a wide variety of scandals that businesses face on a daily basis, particularly in the age of social media and the nature of the viral video. However, the case that solidified this importance in my mind while I was developing the idea for the research was the incident with United Airlines and Dr. David Dao, in which the whole country was outraged by the behavior of the airline and the rough treatment the doctor received as he was bloodied and removed from the plane forcibly. Herein, we have a corporation and the behavior of that corporation toward and external entity. This is the basis for External Organizational Justice research. Moreover, the application of this study of behavior, we examine the impact of this behavior on the employees within that corporation. Will they still identify with the company if they disagree with the exhibited behavior? Will the company lose money because they have employees that will start to willfully behavior negatively in their own job roles? How likely will turnover be impacted, and who within the base of employees is most likely to leave after news like this? Understanding the variables in this research can help answer these questions, but it also reinforces that positive or negative corporate behavior can have farther reaching impacts than a dip in popularity or a momentary drop in stock price
The experiences of first-year school counselors from novice to expert
This study described the common lived experience of 10 first year school counselors. This study explored the experiences within four areas: relationships with staff and students, graduate program training, skills implementation, and relationships with building and district administration. The phenomenology relied on an initial structured interview after eight weeks on the job as the main data source. Other data sources included participant journal entries, non-participant observations, veteran counselor contact logs, and a follow-up interview at the end of the school year. The data triangulation and constant comparative analysis resulted in common themes that described the essence of the common lived experience. There was a level of thoughtful processing and intentional behavior, requiring energy and effort, used to build relationships with staff. The congruence of the counselors\u27 vision of the role with student expectations provided rich opportunities to meet students\u27 needs. The graduate program provided a solid level of preparedness, but could not simulate the reality of the job. The participants identified a wide variety of counseling skills needed in the role and believed they were prepared. The counselors recognized the importance of the principals\u27 understanding and support of the comprehensive guidance program for implementation. The participants appreciated a high level of support and accessibility from several sources for responses to their questions, information, and a sense of “being on the right track.” The generalization of the described common lived experience of these participants is not the expectation of a phenomenological study. A further limitation may be the size of the district studied and the utilization of a comprehensive guidance program. The dual role of researcher as supervisor may have influenced the responses of participants, although the member check suggested that the study captured the essence of their experience. Recommendations for practice included structured support for the novice counselor, the opportunity for an informal reflection process with the guidance supervisor, and well-defined program communication. Further research could enable other districts to determine the common lived experience of first year school counselors and add to the body of literature
Geometric analysis of optical frequency conversion and its control in quadratic nonlinear media
We analyze frequency conversion and its control among three light waves using a geometric approach that enables the dynamics of the waves to be visualized on a closed surface in three dimensions. It extends the analysis based on the undepleted-pump linearization and provides a simple way to understand the fully nonlinear dynamics. The Poincaré sphere has been used in the same way to visualize polarization dynamics. A geometric understanding of control strategies that enhance energy transfer among interacting waves is introduced, and the quasi-phase-matching strategy that uses microstructured quadratic materials is illustrated in this setting for both type I and II second-harmonic generation and for parametric three-wave interactions
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