Aspiring for Change: A Theory of Middle Class Activism

We propose a regime change model in which people are uncertain about both the quality of a specific regime and governance in general. The poor perceive the current regime as bad, rationally infer that all governments are bad, and therefore believe mass movements are futile. The middle class are more sanguine about the prospect of good government, and believe that collective action is effective because they expect many fellow citizens to share the same view. This coordination game with incomplete information does not admit monotone equilibrium but exhibits multiple interval equilibria, where middle class people are more likely to attack the regime.postprin

Falling Dominoes: A Theory of Rare Events and Crisis Contagion

Crises, such as revolutions and currency attacks, rarely occur; but when they do they typically arrive in waves. The rarity of crises itself is an important contagion mechanism in a multiple-country dynamic global game model. When players are uncertain about the true model of the world, observing a rare success elsewhere can substantially change their expectations concerning the payoffs from attacking or defending the regime. Such dramatic revisions in beliefs, amplified by strategic complementarity in actions, may lead to a series of attacks in other countries. The crisis period can be long-lasting, but will eventually come to an end.postprin

A robotic system for rapid prototyping

Reducing prototyping time is a good way to make the product development cycle shorter. This can be achieved in two ways: one is to develop new prototyping technologies like stereolithography apparatus (SLA), selective laser sintering (SLS) etc.; the other is to improve the principal existing technique which is CNC based method. In this paper, a robotic system for rapid prototyping which is an enhancement of the CNC based method is presented. A robot arm holding a milling tool is used to machine the prototype of a solid model drawn in commercial CAD systems. The rough cut and finish cut NC tool path for the robot arm are generated automatically from the solid model of an object. Objects may have different kinds of surfaces e.g. planar surface, general quadratic surface, B-spline surface and compound surface. The proposed method is implemented on the AutoCAD platform. A number of produced prototypes have shown satisfactory results.published_or_final_versio

A new green's function formulation for modeling homogeneous objects in layered medium

A new Green's function formulation is developed systematically for modeling general homogeneous (dielectric or magnetic) objects in a layered medium. The dyadic form of the Green's function is first derived based on the pilot vector potential approach. The matrix representation in the moment method implementation is then derived by applying integration by parts and vector identities. The line integral issue in the matrix representation is investigated, based on the continuity property of the propagation factor and the consistency of the primary term and the secondary term. The extinction theorem is then revisited in the inhomogeneous background and a surface integral equation for general homogeneous objects is set up. Different from the popular mixed potential integral equation formulation, this method avoids the artificial definition of scalar potential. The singularity of the matrix representation of the Green's function can be made as weak as possible. Several numerical results are demonstrated to validate the formulation developed in this paper. Finally, the duality principle of the layered medium Green's function is discussed in the appendix to make the formulation succinct. © 1963-2012 IEEE.published_or_final_versio

Current assays for HIV-1 diagnostics and antiretroviral therapy monitoring: challenges and possibilities

In 2011, there were over 34 million people living with HIV infections, placing a heavy burden on public health sectors. HIV infection is a lifelong threat that cannot be prevented by vaccination or cured by antiretroviral drugs. The infected patients rely on daily antiretroviral therapy to suppress HIV viral replication. Hence, it is important to diagnose HIV infections as early as possible and to monitor the efficacy of antiretroviral therapy every 3–6 months. Different immunoassays detecting HIV antigens and antibodies have been modified to offer better sensitivity and more rapid diagnosis. Several clinical and virological parameters, including CD4+ cell counts, viral load and drug resistance mutations, are also used for treatment monitoring. Many molecular assay optimizations are now being utilized to improve patient care. This review will focus on the most updated HIV diagnostic assays, as well as discussing the upcoming possibilities of other advanced technologies.postprin

A novel implementation of discrete complex image method for layered medium Green's function

A novel implementation of discrete complex image method (DCIM) based on the Sommmerfeld branch cut is proposed to accurately capture the far-field behavior of the layered medium Green's function as a complement to the traditional DCIM. By contour deformation, the Green's function can be naturally decomposed into branch-cut integration (radiation modes) and pole contributions (guided modes). For branch-cut integration, matrix pencil method is applied, and the alternative Sommerfeld identity in terms of k z integration is utilized to get a closed-form solution. The guided modes are accounted for with a pole-searching algorithm. Both one-branch-cut and two-branch-cut cases are studied. Several numerical results are presented to validate this method. © 2011 IEEE.published_or_final_versio

A new closed-form evaluation of layered medium Green'S function

A new closed-form evaluation of layered medium Green's function is proposed in this paper. The discrete complex image method (DCIM) is extended to sampling along the Sommerfeld branch cut, to capture the far field interaction. Contour deformation technique is applied to decompose the Green's function into radiation modes (branch cut integration) and guided modes (surface-wave poles). The matrix pencil method is implemented to get a closed-form solution, with the help of an alternative Sommerfeld identity. Numerical results are presented to demonstrate the accuracy of this method. © 2011 IEEE.published_or_final_versionThe 2011 IEEE International Symposium on Antennas and Propagation (APSURSI), Spokane, WA., 3-8 July 2011. In IEEE Antennas and Propagation Society. International Symposium, 2011, p. 3211-321

The Power of Whispers: A Theory of Rumor, Communication, and Revolution

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Acarbose: A New Option in the Treatment of Ulcerative Colitis by Increasing Hydrogen Production

Acarbose，which is clinically widely used to treat Type 2 Diabetes，is thought to act at the small intestine by competitively inhibiting enzymes that delay the release of glucose from complex carbohydrates, thereby specifically reducing post prandial glucose excursion. The major side-effect of treatment with acarbose, flatulence, occurs when undigested carbohydrates are fermented by colonic bacteria, resulting in considerable amount of hydrogen. We propose that enteric benefits of acarbose is partly attributable to be their ability to neutralise oxidative stress via increased production of H2 in the gastrointestinal tract. Therefore, symptoms of ulcerative colitis in human beings can be ameliorated by acarbose

Numerically efficient formulation for time-domain electromagnetic-semiconductor co-simulation for Fast-Transient Systems

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