The 2+1 Kepler Problem and Its Quantization

We study a system of two pointlike particles coupled to three dimensional Einstein gravity. The reduced phase space can be considered as a deformed version of the phase space of two special-relativistic point particles in the centre of mass frame. When the system is quantized, we find some possibly general effects of quantum gravity, such as a minimal distances and a foaminess of the spacetime at the order of the Planck length. We also obtain a quantization of geometry, which restricts the possible asymptotic geometries of the universe.Comment: 59 pages, LaTeX2e, 9 eps figure

Theoretical Models of Cyst Formation and Growth

Although the formation of fluid-filled, epithelial-lined cysts is a common event in a variety of tissues, the mechanisms involved are not well understood. Discussed here are means by which those mechanisms might be elucidated. In general, there are too few data available for complete analysis of in vivo disease processes. It can be suggested only that epithelial proliferation and basement membrane growth are probably absolute requirements. Whether the forces for fluid accumulation precede or follow the stimuli for cell growth cannot be stated with certainty. On the other hand, in certain in vitro model systems the forces required to keep cyst cavities filled with fluid may be so small that cell growth, rather than fluid accumulation, seems the more likely primary event

Non-governmental Organizations, Prevention, and Intervention in Internal Conflicts: Though the Lens of Darfur

This Note argues that cases like the humanitarian crisis and the conflict in Darfur, Sudan, present an intrastate collective action problem that has not been satisfactorily addressed by a traditional multilateral approach. Instead, the Darfur crisis demonstrates the need for an expanded view of modern international law in the face of intrastate conflict that includes systematic intervention procedures and preventive aid, as well as a multifaceted approach that recognizes and integrates NGOs and NGO alliances. This Note asserts that the Sudan crisis has posed a collective action problem requiring not only multilateral state collective action, but also multifaceted, coordinated action between states and the proliferation of nonstate actors that have emerged from globalization. Part I provides background on the genocide in Sudan and demonstrates that this conflict is one of a number of recent intrastate conflicts. It argues that intrastate conflicts and humanitarian crises are collective action problems. Part II argues that humanitarian crises and internal wars require new international aw that encourages collective, preventive aid and systemized preemptive intervention procedures. Part III argues that these newer collective actions under international law should involve coordinated action between states and NGOs

Non-governmental Organizations, Prevention, and Intervention in Internal Conflicts: Though the Lens of Darfur

This Note argues that cases like the humanitarian crisis and the conflict in Darfur, Sudan, present an intrastate collective action problem that has not been satisfactorily addressed by a traditional multilateral approach. Instead, the Darfur crisis demonstrates the need for an expanded view of modern international law in the face of intrastate conflict that includes systematic intervention procedures and preventive aid, as well as a multifaceted approach that recognizes and integrates NGOs and NGO alliances. This Note asserts that the Sudan crisis has posed a collective action problem requiring not only multilateral state collective action, but also multifaceted, coordinated action between states and the proliferation of nonstate actors that have emerged from globalization. Part I provides background on the genocide in Sudan and demonstrates that this conflict is one of a number of recent intrastate conflicts. It argues that intrastate conflicts and humanitarian crises are collective action problems. Part II argues that humanitarian crises and internal wars require new international aw that encourages collective, preventive aid and systemized preemptive intervention procedures. Part III argues that these newer collective actions under international law should involve coordinated action between states and NGOs

Dynamic roughening of the magnetic flux landscape in YBa2_2Cu3_3O7−x_{7-x}

We study the magnetic flux landscape in YBa$_2$Cu$_3$O$_{7-x}$ thin films as a two dimensional rough surface. The vortex density in the superconductor forms a self-affine structure in both space and time. This is characterized by a roughness exponent $\alpha = 0.76(3)$ and a growth exponent $\beta = 0.57(6)$. This is due to the structure and distribution of flux avalanches in the self-organized critical state, which is formed in the superconductor. We also discuss our results in the context of other roughening systems in the presence of quenched disorder.Comment: 13 pages, 7 figures, accepted for publication in Physica

Faculty and Student Perception of Open Educational Resources in Higher Education

There is an ever-increasing rise in higher education, including the price of textbooks. Students are choosing to not purchase textbooks to save money. An alternative to this problem needs to occur. One solution is the use of Open Educational Resources (OER). OER improves the cost and quality of course materials for students and makes the materials accessible, thus promoting equity among all students. When all students have access to the materials on the first day, they become more engaged with the course. This paper describes the benefits of OER in higher education and the student and faculty perceptions. To make OER a realization, faculty need to become aware of what OER entails. This paper describes OER, to bring that realization to faculty

The Torus Universe in the Polygon Approach to 2+1-Dimensional Gravity

In this paper we describe the matter-free toroidal spacetime in 't Hooft's polygon approach to 2+1-dimensional gravity (i.e. we consider the case without any particles present). Contrary to earlier results in the literature we find that it is not possible to describe the torus by just one polygon but we need at least two polygons. We also show that the constraint algebra of the polygons closes.Comment: 18 pages Latex, 13 eps-figure