The Null Condition and Global Existence for Nonlinear Wave Equations on Slowly Rotating Kerr Spacetimes

We study a semilinear equation with derivatives satisfying a null condition on slowly rotating Kerr spacetimes. We prove that given sufficiently small initial data, the solution exists globally in time and decays with a quantitative rate to the trivial solution. The proof uses the robust vector field method. It makes use of the decay properties of the linear wave equation on Kerr spacetime, in particular the improved decay rates in the region $\{r\leq \frac{t}{4}\}$

Removing the Digital Divide for Senior Web Users

It is hard for the elderly to use the internet to find the resource they want. Usually help is needed for them to complete the task on the technology things. The main reason for this project is to research ideas on encourage senior people to make use of the web to locate helps they want, such as finding volunteers and professional helps. The scope of this project is to develop a new way of web access and content presentation methodologies that let senior people getting help from volunteers and various service providers more easily that incorporates social networking technology e.g. Facebook. By incorporating the social network web site like Facebook into the web application, senior people will be able to find volunteering help or other related service providers through social networking. Volunteers will show up in Google map in search results for senior to easily locate helps. Senior people can also search for self help videos tutorials through the web application search engine. A mobile version of the senior user application will also be developed for easy access on the road. Other features that benefit senior users includes voice input, control / content posting and collaborative social networking where a sponsors would sponsor a help task volunteer undertake

Examining CP Symmetry in Strange Baryon Decays

Non-conservation of CP symmetry can manisfest itself in non-leptonic hyperon decays as a difference in the decay parameter between the strange-baryon decay and its charge conjugate. By comparing the decay distribution in the $\Lambda$ helicity frame for the decay sequence $\Xi^{-} \to \Lambda \pi^{-}$, $\Lambda \to p \pi^{-}$ with that of $\bar{\Xi}^{+}$ decay, E756 at Fermilab did not observe any CP-odd effect at the $10^{-2}$ level. The status of a follow-up experiment, HyperCP (FNAL E871), to search for CP violation in charged $\Xi-\Lambda$ decay with a sensitivity of $10^{-4}$ is also presented.Comment: 9 pages, 4 figures, invited talk presented at the Third International Conference on B Physics and CP Violation, 3-7 Dec 1999, Taipei, Taiwa

The EU as a Global Actor in a Multipolar World and Multilateral 2.0 Environment. Egmont Paper No. 36, March 2010

This paper discusses a number of long-term global trends that are likely to affect the ambition of the EU to be a global actor. Being or becoming a global power is indeed not only determined by an internal and voluntary policy of that actor. It also depends on a number of external forces. The first part of this paper will present two ongoing transformations of the world that together are weakening the position of the EU as an aspiring global power. The first trend is a shift in economic gravity from the East to the West. The second trend is a demographic decline in Europe. Both trends make it increasingly difficult for the EU to be a global power. But at the same time one can also identify a number of developments with regard to multilateralism that bear in them opportunities for the EU to increase its influence as a global actor. The second part of this paper focuses on two such trends, the shift to multipolarity and the changes in the multilateral architecture. As for the latter, this paper introduces the notion of 'multilateralism 2.0.' as a metaphor to grasp these changes

Local Propagation of Impulsive Gravitational Waves

In this paper, we initiate the rigorous mathematical study of the problem of impulsive gravitational spacetime waves. We construct such spacetimes as solutions to the characteristic initial value problem of the Einstein vacuum equations with a data curvature delta singularity. We show that in the resulting spacetime, the delta singularity propagates along a characteristic hypersurface, while away from that hypersurface the spacetime remains smooth. Unlike the known explicit examples of impulsive gravitational spacetimes, this work in particular provides the first construction of an impulsive gravitational wave of compact extent and does not require any symmetry assumptions. The arguments in the present paper also extend to the problem of existence and uniqueness of solutions to a larger class of non-regular characteristic data

Angle Combinations in Spherical Tilings by Congruent Pentagons

We develop a systematic method for computing the angle combinations in spherical tilings by angle congruent pentagons, and study whether such combinations can be realized by actual angle or geometrically congruent tilings. We get major families of angle or geometrically congruent tilings related to the platonic solids.Comment: 58 pages, 5 figure

Spirituality and business: An interdisciplinary overview

The paper gives an interdisciplinary overview of the emerging field of spirituality and business. It uses insights from business ethics, theology, neuroscience, psychology, gender studies, and philosophy to economics, management, organizational science, and banking and refers to different religious convictions including Christianity, Judaism, Islam, Hinduism, Buddhism, Confucianism, the Baha'i faith, and the North-American aboriginal worldview. The authors argue that the materialistic management paradigm has failed. They explore new values for post-materialistic management: frugality, deep ecology, trust, reciprocity, responsibility for future generations, and authenticity. Within this framework profit and growth are no longer ultimate aims but elements in a wider set of values. Similarly, cost-benefit calculations are no longer the essence of management but are part of a broader concept of wisdom in leadership. Spirit-driven businesses require intrinsic motivation for serving the common good and using holistic evaluation schemes for measuring success. The Palgrave Handbook of Business and Spirituality, edited by the authors, is a response to developments that simultaneously challenge the “business as usual” mindset

Trapped surfaces in vacuum arising dynamically from mild incoming radiation

In this paper, we study the "minimal requirement" on the incoming radiation that guarantees a trapped surface to form in vacuum. First, we extend the region of existence in Christodoulou's theorem on the formation of trapped surfaces and consequently show that the lower bound required to form a trapped surface can be relaxed. Second, we demonstrate that trapped surfaces form dynamically from a class of initial data which are large merely in a scaling-critical norm. This result is motivated in part by the scaling in Christodoulou's formation of trapped surfaces theorem for the Einstein-scalar field system in spherical symmetry