Cancellation of linearised axion-dilaton self interaction divergence in strings

The force densities exerted on a localised material system by linearised interaction with fields of axionic and dilatonic type are shown to be describable very generally by relatively simple expressions that are well behaved for fields of purely external origin, but that will be subject to ultraviolet divergences requiring regularisation for fields arising from self interaction in submanifold supported ``brane'' type systems. In the particular case of 2-dimensionally supported, i.e. string type, system in an ordinary 4-dimensional background it is shown how the result of this regularisation is expressible in terms of the worldsheet curvature vector $K^\mu$, and more particularly that (contrary to what was suggested by early work on this subject) for a string of Nambu Goto type the divergent contribution from the dilatonic self action will always be directed oppositely to its axionic counterpart. This makes it possible for the dilatonic and axionic divergences to entirely cancel each other out (so that there is no need of a renormalisation to get rid of ``infinities'') when the relevant coupling coefficents are related by the appropriate proportionality condition provided by the low energy limit of superstring theory.Comment: 20 pages Latex. Contrib. to 1998 Peyresq meeting; to be published in Int. J. Theor. Phy

'The Accidental Birth of Hate Crime in Transnational Criminal Law: 'Discrepancies' in the Prosecution for "Incitement to Genocide" during the Nuremberg Process involving the cases of Julius Streicher, Hans Fritzsche and Carl Schmitt.'

This volume of three interrelated studies aims to explore the various contingencies through which individuals responsible, to various degrees, for promoting expressions of racist hate were subjected to markedly different types of legal responses within the landmark Nuremberg trials programme. These contingencies, together with loose judicial reasoning, complicate scholarly efforts to identify the historical emergence of this type of transnational hate crime, and to illustrate the complications that arise when seeking to ascertain its implications as a precedent. It needs to be emphasised at the outset that what follows is not a comprehensive study of the origins of the criminalisation of hate speech in general as this would have to include a full comparative survey of all domestic laws and their judicial interpretation, application and institutional enforcement. In addition, the interaction between domestic, regional and international criminalisations would also have to be addressed in what would amount to a massive multi-volume study, beyond the scope of this study. It is acknowledged that a strong case can be made for a more comprehensive approach, placing the contents of what follows within this wider context of transnational regulation. For example, there has clearly been a measure of interaction, albeit of an inconsistent type, between US immigration and naturalisation law and practice, and international criminal law relating to hate speech, with the Streicher case expressly referred to as a precedent for the idea that "persecution," as a subset of crimes against humanity, can include racist and anti-Semitic propaganda

Contributions of Repulsive and Attractive Interactions to Nematic Order

Both repulsive and attractive molecular interactions can be used to explain the onset of nematic order. The object of this paper is to combine these two nematogenic molecular interactions in a unified theory. This attempt is not unprecedented; what is perhaps new is the focus on the understanding of nematics in the high density limit. There, the orientational probability distribution is shown to exhibit a unique feature: it has compact support on configuration space. As attractive interactions are turned on, the behavior changes, and at a critical attractive interaction strength, thermotropic behavior of the Maier-Saupe type is attained.Comment: 14 pages, 4 figure

Bright-like soliton solution in quasi-one-dimensional BEC in third order on interaction radius

Nonlinear Schr\"{o}dinger equations and corresponding quantum hydrodynamic (QHD) equations are widely used in studying ultracold boson-fermion mixtures and superconductors. In this article, we show that a more exact account of interaction in Bose-Einstein condensate (BEC), in comparison with the Gross-Pitaevskii (GP) approximation, leads to the existence of a new type of solitons. We use a set of QHD equations in the third order by the interaction radius (TOIR), which corresponds to the GP equation in a first order by the interaction radius. The solution for the soliton in a form of expression for the particle concentration is obtained analytically. The conditions of existence of the soliton are studied. It is shown what solution exists if the interaction between the particles is repulsive. Particle concentration of order of $10^{12}$-$10^{14}$ $cm^{-3}$ has been achieved experimentally for the BEC, the solution exists if the scattering length is of the order of 1 $\mu$m, which can be reached using the Feshbach resonance. It is one of the limit case of existence of new solution. The corresponding scattering length decrease with the increasing of concentration of particles. The investigation of effects in the TOIR approximation gives a more detail information on interaction potentials between the atoms and can be used for a more detail investigation into the potential structure.Comment: 7 pages, 3 figure

Using acoustic sensor technologies to create a more terrain capable unmanned ground vehicle

Unmanned Ground Vehicle’s (UGV) have to cope with the most complex range of dynamic and variable obstacles and therefore need to be highly intelligent in order to cope with navigating in such a cluttered environment. When traversing over different terrains (whether it is a UGV or a commercial manned vehicle) different drive styles and configuration settings need to be selected in order to travel successfully over each terrain type. These settings are usually selected by a human operator in manned systems on what they assume the ground conditions to be, but how can an autonomous UGV ‘sense’ these changes in terrain or ground conditions? This paper will investigate noncontact acoustic sensor technologies and how they can be used to detect different terrain types by listening to the interaction between the wheel and the terrain. The results can then be used to create a terrain classification list for the system so in future missions it can use the sensor technology to identify the terrain type it is trying to traverse, which creating a more autonomous and terrain capable vehicle. The technology would also benefit commercial driver assistive technologie

Acute: high-level programming language design for distributed computation

Existing languages provide good support for typeful programming of standalone programs. In a distributed system, however, there may be interaction between multiple instances of many distinct programs, sharing some (but not necessarily all) of their module structure, and with some instances rebuilt with new versions of certain modules as time goes on. In this paper we discuss programming language support for such systems, focussing on their typing and naming issues. We describe an experimental language, Acute, which extends an ML core to support distributed development, deployment, and execution, allowing type-safe interaction between separately-built programs. The main features are: (1) type-safe marshalling of arbitrary values; (2) type names that are generated (freshly and by hashing) to ensure that type equality tests suffice to protect the invariants of abstract types, across the entire distributed system; (3) expression-level names generated to ensure that name equality tests suffice for type-safety of associated values, e.g. values carried on named channels; (4) controlled dynamic rebinding of marshalled values to local resources; and (5) thunkification of threads and mutexes to support computation mobility. These features are a large part of what is needed for typeful distributed programming. They are a relatively lightweight extension of ML, should be efficiently implementable, and are expressive enough to enable a wide variety of distributed infrastructure layers to be written as simple library code above the byte-string network and persistent store APIs. This disentangles the language runtime from communication intricacies. This paper highlights the main design choices in Acute. It is supported by a full language definition (of typing, compilation, and operational semantics), by a prototype implementation, and by example distribution libraries

Composite Leptons at the LHC

In some models of electro-weak interactions the W and Z bosons are considered composites, made up of spin-one-half subconstituents. In these models a spin zero counterpart of the W and Z boson naturally appears, whose higher mass can be attributed to a particular type of hyperfine spin interaction among the various subconstituents. Recently it has been argued that the scalar state could be identified with the newly discovered Higgs (H) candidate. Here we use the known spin splitting between the W/Z and H states to infer, within the framework of a purely phenomenological model, the relative strength of the spin-spin interactions. The results are then applied to the lepton sector, and used to crudely estimate the relevant spin splitting between the two lowest states. Our calculations in many ways parallels what is done in the SU(6) quark model, where most of the spin splittings between the lowest lying baryon and meson states are reasonably well accounted for by a simple color hyperfine interaction, with constituent (color-dressed) quark masses.Comment: 12 pages, footnotes added. Conforms to published versio

The Macroeconomist as Scientist and Engineer

This essay offers a brief history of macroeconomics, together with an evaluation of what has been learned over the past several decades. It is based on the premise that the field has evolved through the efforts of two types of macroeconomist—those who understand the field as a type of engineering and those who would like it to be more of a science. While the early macroeconomists were engineers trying to solve practical problems, macroeconomists have more recently focused on developing analytic tools and establishing theoretical principles. These tools and principles, however, have been slow to find their way into applications. As the field of macroeconomics has evolved, one recurrent theme is the interaction—sometimes productive and sometimes not— between the scientists and the engineers.