Excited Q-Balls in the MSSM with gravity mediated supersymmetry breaking

Excited Q-balls are studied by numerical simulations in the Minimal Supersymmetric Standard Model with supersymmetry broken by a gravity mediated mechanism. It is found that there is a suppression factor of \cO(10^{-2}) in the rate at which a Q-ball can emit their excess energy compared to the rate set by the dynamical scale of the field, $m$. Furthermore, it is noted that a Q-ball can withstand a large amount of excess energy without losing a significant amount of its charge. The cosmological importance of these properties are considered for Q-balls in the thermal bath of the early universe.Comment: 12 pages, 4 figure

Non-existence of multi-line Besicovitch sets

If a compact set K \subset R^2 contains a positive-dimensional family of line-segments in positively many directions, then K has positive measure.Comment: 7 pages. v2: corrected typos and added references, to appear in Publ. Ma

Glocalisation of global market forces and the repositioning of a peripheral Russian mining community

Increasing globalisation and global market forces shape the development of resource peripheries in the Barents region. Foreign direct investments are concrete example of global market forces. Their glocalisation forces the locals to evaluate their consequences for the local development and reposition their communities in global context. This article studies glocalisation of global market forces and preferred directions of repositioning of a peripheral single-industry mining community in the Russian Barents region. The study is based on a case study of local opinions about actual and potential external actors in the economic development of Kovdor, located in the Murmansk region. The paper analyses the preferred owner of the town-constituting enterprise and the local opinions about the EU, USA and China as potential investors to the case study community. The study reveals how local opinions about external forces in the local development are related to local life-worlds. Moreover, the paper shows the impact that economic, political, cultural, historical and technological factors have in forming these opinions about potential foreign investors. The study shows generally positive local opinions about FDI. However, significant differences were found in opinions about different investing countries.publishedVersio

Universal Voting Protocol Tweaks to Make Manipulation Hard

Voting is a general method for preference aggregation in multiagent settings, but seminal results have shown that all (nondictatorial) voting protocols are manipulable. One could try to avoid manipulation by using voting protocols where determining a beneficial manipulation is hard computationally. A number of recent papers study the complexity of manipulating existing protocols. This paper is the first work to take the next step of designing new protocols that are especially hard to manipulate. Rather than designing these new protocols from scratch, we instead show how to tweak existing protocols to make manipulation hard, while leaving much of the original nature of the protocol intact. The tweak studied consists of adding one elimination preround to the election. Surprisingly, this extremely simple and universal tweak makes typical protocols hard to manipulate! The protocols become NP-hard, #P-hard, or PSPACE-hard to manipulate, depending on whether the schedule of the preround is determined before the votes are collected, after the votes are collected, or the scheduling and the vote collecting are interleaved, respectively. We prove general sufficient conditions on the protocols for this tweak to introduce the hardness, and show that the most common voting protocols satisfy those conditions. These are the first results in voting settings where manipulation is in a higher complexity class than NP (presuming PSPACE $\neq$ NP)