SOPHIA

The Iraqi Insurgency (2003–2011) has commonly been characterized as demonstrating the tendency for violence to cluster and diffuse at the local level. Recent research has demonstrated that insurgent attacks in Iraq cluster in time and space in a manner similar to that observed for the spread of a disease. The current study employs a variety of approaches common to the scientific study of criminal activities to advance our understanding of the correlates of observed patterns of the incidence and contagion of insurgent attacks. We hypothesize that the precise patterns will vary from one place to another, but that more attacks will occur in areas that are heavily populated, where coalition forces are active, and along road networks. To test these hypotheses, we use a fishnet to build a geographical model of Baghdad that disaggregates the city into more than 3000 grid cell locations. A number of logistic regression models with spatial and temporal lags are employed to explore patterns of local escalation and diffusion. These models demonstrate the validity of arguments under each of three models but suggest, overall, that risk heterogeneity arguments provide the most compelling and consistent account of the location of insurgency. In particular, the results demonstrate that violence is most likely at locations with greater population levels, higher density of roads, and military garrisons

Does poverty cause conflict? Isolating the causal origins of the conflict trap

Does poverty cause civil conflict? A considerable literature seeks to answer this question, yet concerns about reverse causality threaten the validity of extant conclusions. To estimate the impact of poverty on conflict and to determine whether the relationship between them is causal, it is necessary to identify a source of exogenous variation in poverty. We do this by introducing a robust instrument for poverty: a time-varying measure of international inequalities. We draw upon existing theories about the structural position of a country in the international economic network—specifically, the expectation that countries in the core tend to be wealthier and those on the periphery struggle to develop. This instrument is plausibly exogenous and satisfies the exclusion restriction, which suggests that it affects conflict only through its influence upon poverty. Instrumental variables probit regression is employed to demonstrate that the impact of poverty upon conflict appears to be causal

Hall drift of axisymmetric magnetic fields in solid neutron-star matter

Hall drift, i. e., transport of magnetic flux by the moving electrons giving rise to the electrical current, may be the dominant effect causing the evolution of the magnetic field in the solid crust of neutron stars. It is a nonlinear process that, despite a number of efforts, is still not fully understood. We use the Hall induction equation in axial symmetry to obtain some general properties of nonevolving fields, as well as analyzing the evolution of purely toroidal fields, their poloidal perturbations, and current-free, purely poloidal fields. We also analyze energy conservation in Hall instabilities and write down a variational principle for Hall equilibria. We show that the evolution of any toroidal magnetic field can be described by Burgers' equation, as previously found in plane-parallel geometry. It leads to sharp current sheets that dissipate on the Hall time scale, yielding a stationary field configuration that depends on a single, suitably defined coordinate. This field, however, is unstable to poloidal perturbations, which grow as their field lines are stretched by the background electron flow, as in instabilities earlier found numerically. On the other hand, current-free poloidal configurations are stable and could represent a long-lived crustal field supported by currents in the fluid stellar core.Comment: 8 pages, 5 figure panels; new version with very small correction; accepted by Astronomy & Astrophysic

Relativistic models of magnetars: the twisted-torus magnetic field configuration

We find general relativistic solutions of equilibrium magnetic field configurations in magnetars, extending previous results of Colaiuda et al. (2008). Our method is based on the solution of the relativistic Grad-Shafranov equation, to which Maxwell's equations can be reduced in some limit. We obtain equilibrium solutions with the toroidal magnetic field component confined into a finite region inside the star, and the poloidal component extending to the exterior. These so-called twisted-torus configurations have been found to be the final outcome of dynamical simulations in the framework of Newtonian gravity, and appear to be more stable than other configurations. The solutions include higher order multipoles, which are coupled to the dominant dipolar field. We use arguments of minimal energy to constrain the ratio of the toroidal to the poloidal field.Comment: 13 pages, 12 figures. Minor changes to match the version published on MNRA

Instructional Communication Strategies for Adapting to a Multicultural Introductory Course

No educator is surprised to hear that college enrollment for members of racial and ethnic groups is continuing to rise (The Chronicle of Higher Education, 1990). However, this increase was particularly striking for us after we began teaching in the southwestern United States. We had moved from Minnesota, where the proportion of college students who are minority-group members is only 4%, to New Mexico where the proportion of college students who are minority-group members is 35%, the highest for any state in the continental United States (The Chronicle of Higher Education, 1990). We now look out into multicultural classrooms that will increase in cultural diversity year after year. As a result of this increase in cultural diversity, one question facing those responsible for teaching communication courses is: What changes, if any, are needed in the instructional strategies for teaching in a multicultural introductory communication course? Many of us often forget that our teaching is also grounded in a theoretical perspective. Exploring and making our theoretical perspective explicit functions to help us deal with problems and changes occurring in the classrooms and allows us to respond to changes in a systematic manner. For us, the best way to answer the question about how to adapt to multicultural classrooms is to take a theoretical perspective that is grounded in the ethnographic literature. An ethnographic approach to communication education focuses on the use of situationally grounded studies and the comparative analysis of cultures. The concepts, methods, and resources that take an ethnographic perspective on communication will prove fruitful for improving our courses and help us deal with the multicultural classrooms we now face or will face in the near future. To begin to answer the question about teaching in the multicultural introductory communication course, we examined current literature, analyzed situations occurring in our own classrooms, and surveyed students about their perceptions of the courses in which they were enrolled. Based on our investigations, we will describe several instructional communication strategies we argue may be used to adapt communication courses to an increasingly diverse student population. We will present strategies in four general areas of teaching in the introductory communication course: a) Expanding the parameters of culture, b) Language, c) Assignments, and d) Resources. Finally, we will discuss issues of evaluation of teaching effectiveness in the multicultural classroom

An engineering feasibility study of an orbiting scanning radiometer

Engineering feasibility study of lunar orbiting optical scanning radiometer

The MiMeS Project: Magnetism in Massive Stars

The Magnetism in Massive Stars (MiMeS) Project is a consensus collaboration among the foremost international researchers of the physics of hot, massive stars, with the basic aim of understanding the origin, evolution and impact of magnetic fields in these objects. The cornerstone of the project is the MiMeS Large Program at the Canada-France-Hawaii Telescope, which represents a dedication of 640 hours of telescope time from 2008-2012. The MiMeS Large Program will exploit the unique capabilities of the ESPaDOnS spectropolarimeter to obtain critical missing information about the poorly-studied magnetic properties of these important stars, to confront current models and to guide theory.Comment: 6 pages, 3 figures, proceedings of IAUS 259: Cosmic Magnetic Field

Review of \u3ci\u3eHistoric Photos of Nebraska\u3c/i\u3e text and captions by Ted Stryker

One of the salient features of Great Plains Quarterly is its inclusion of an extensive array of illustrations, maps, and photographs along with most articles. These images are meant to enhance their essays and enrich the reader\u27s understanding of their contexts. Occasionally, pictures say so much that one wishes for more photographs and less text. That\u27s not a weakness of Historic Photos of Nebraska, which contains 192 photographs in its 216 pages. This is Turner Publishing\u27s second book focused on the region\u27s photographs; the first was Jeffrey Spencer\u27s Historic Photos of Omaha (2007). Using images selected from the Boys Town Hall of History, the Denver Public Library, the Library of Congress, the Nebraska State Historical Society, and photos from the collections of Frederick Bandholtz and Solomon D. Butcher, Ted Stryker presents a broad panorama of the visual history of Nebraska from the 1850s to the 1970s: Standing Bear and Buffalo Bill; Kosher butchers and Irish farmers; Willa Cather and Johnny Carson; sod houses and main streets; politicians and tornadoes

Search for Stable Magnetohydrodynamic Equilibria in Barotropic Stars

It is now believed that magnetohydrodynamic equilibria can exist in stably stratified stars due to the seminal works of Braithwaite & Spruit (2004) and Braithwaite & Nordlund (2006). What is still not known is whether magnetohydrodynamic equilibria can exist in a barotropic star, in which stable stratification is not present. It has been conjectured by Reisenegger (2009) that there will likely not exist any magnetohydrodynamical equilibria in barotropic stars. We aim to test this claim by presenting preliminary MHD simulations of barotropic stars using the three dimensional stagger code of Nordlund & Galsgaard (1995).Comment: 4 pages, 2 figures, to appear in the proceedings of IAUS 302: "Magnetic Fields Throughout Stellar Evolution

Review of \u3ci\u3eHistoric Photos of Nebraska\u3c/i\u3e text and captions by Ted Stryker

One of the salient features of Great Plains Quarterly is its inclusion of an extensive array of illustrations, maps, and photographs along with most articles. These images are meant to enhance their essays and enrich the reader\u27s understanding of their contexts. Occasionally, pictures say so much that one wishes for more photographs and less text. That\u27s not a weakness of Historic Photos of Nebraska, which contains 192 photographs in its 216 pages. This is Turner Publishing\u27s second book focused on the region\u27s photographs; the first was Jeffrey Spencer\u27s Historic Photos of Omaha (2007). Using images selected from the Boys Town Hall of History, the Denver Public Library, the Library of Congress, the Nebraska State Historical Society, and photos from the collections of Frederick Bandholtz and Solomon D. Butcher, Ted Stryker presents a broad panorama of the visual history of Nebraska from the 1850s to the 1970s: Standing Bear and Buffalo Bill; Kosher butchers and Irish farmers; Willa Cather and Johnny Carson; sod houses and main streets; politicians and tornadoes