An Integrated Approach to Seismic Event Location: 1. Evaluating How Method of Location Affects the Volume of Groups of Hypocenters

When seismic events occur in spatially compact clusters, the volume and geometric characteristics of these clusters often provides information about the relative effectiveness of different location methods, or about physical processes occurring within the hypocentral region. This report defines and explains how to determine the convex polyhedron of minimum volume (CPMV) surrounding a set of points. We evaluate both single-event and joint hypocenter determination (JHD) relocations for three rather different clusters of seismic events: 1) nuclear explosions from Mururoa relocated using P and PKP phases reported by the ISC, 2) intermediate depth earthquakes near Bucaramanga, Colombia, relocated using P and PKP phases reported by the ISC, and 3) shallow earthquakes near Vanuatu (formerly, the New Hebrides), relocated using P and S phases from a local station network. This analysis demonstrates that different location methods markedly affect the volume of the CPMV, however, volumes for JHD relations are �not always smaller than volumes for single-event relocations.Phillips Laboratory, Directorate of Geophysics, Air Force Material Command, Hanscom Air Force Base, MassachusettsInstitute for Geophysic

Conformal Field Theory and Geometry of Strings

What is quantum geometry? This question is becoming a popular leitmotiv in theoretical physics and in mathematics. Conformal field theory may catch a glimpse of the right answer. We review global aspects of the geometry of conformal fields, such as duality and mirror symmetry, and interpret them within Connes' non-commutative geometry. Extended version of lectures given by the 2nd author at the Mathematical Quantum Theory Conference, Vancouver, Canada, August 4 to 8, 1993Comment: 44 pages, latex file, 5 references adde

Magnetohydrodynamics of Chiral Relativistic Fluids

We study the dynamics of a plasma of charged relativistic fermions at very high temperature $T\gg m$, where $m$ is the fermion mass, coupled to the electromagnetic field. In particular, we derive a magneto-hydrodynamical description of the evolution of such a plasma. We show that, as compared to conventional MHD for a plasma of non-relativistic particles, the hydrodynamical description of the relativistic plasma involves new degrees of freedom described by a pseudo-scalar field originating in a local asymmetry in the densities of left-handed and right-handed fermions. This field can be interpreted as an effective axion field. Taking into account the chiral anomaly we present dynamical equations for the evolution of this field, as well as of other fields appearing in the MHD description of the plasma. Due to its non-linear coupling to helical magnetic fields, the axion field significantly affects the dynamics of a magnetized plasma and can give rise to a novel type of inverse cascade

A Cluster Expansion for Dipole Gases

We give a new proof of the well-known upper bound on the correlation function of a gas of non-overlapping dipoles of fixed length and discrete orientation working directly in the charge representation, instead of the more usual sine-Gordon representation.Comment: 8 pages, Late

Cliff's Nodes Concerning Plotting Nodal Lines for P, Sh, and Sv

The purpose of this technical report is to provide background� information for a Fortran program package CliffsNodes.PShSv for plotting focal mechanisms and nodal lines.Institute for Geophysic

Croatian Regional Strategy in the Framework of the EU Accession Process

A limitation on the implementation of modern regional policy in Croatia is the inherited doctrine of the reconstruction of war affected areas. This doctrine is no longer appropriate to the needs of new regional policy, which must be formulated in the context of EU accession. This is especially important considering that the EU emphasizes that member states must be in a position to withstand competitive pressures in the single market as a key condition for accession. In this context, regional policy will be closely tied into the accession strategy. A major objective will be to prepare for the introduction of EU cohesion policy and the Structural Funds. The pre-accession funds will contribute to that effort. The situation in Croatia today is that while “balanced regional development†is one of seven key government priorities, there is no clear definition of what this means. There is a fragmented listing of regions deemed to have special problems without, on the face of it, any coherent profile of those development needs. The National Strategy for Regional Development will seek to address these issues. The implications, therefore, for approach to the analysis of regional policy in Croatia today is that we concentrate essentially upon three main fields of enquiry from two perspectives – top-down and bottom-up. These are: • Assessment of the overall policy framework for regional development, including the current legal framework in particular policies, legal acts and regulations which affect the development of those parts of the country which can be loosely termed “assisted areasâ€. • Assessment of the institutional and administrative capacity in place. • Appraisal of the types of regional development instruments currently deployed and their effectiveness in dealing with development needs at national, regional and local level. The strategy sets the context for balanced regional development both at national and sub-national level as well as draws attention to development needs of the ‘assisted areas’ as well as counties highlighting their different development profiles. It brings together the main analytical parts – policy framework, institutional context and finally an assessment of the existing development interventions. This is followed by a SWOT analysis before moving to a set of conclusions and next steps which will frame the strategic rationale behind the strategy. The paper is linked to the project Strategy and Capacity Building for Regional Development (CARDS 2002 Programme for Croatia): Analysis Section for Strategy.

Role of small and medium sized enterprises in the regional development of Croatia

The paper will reflect upon the crucial role of small and medium sized enterprises (SME's) in Croatia's local and regional development, particulary in circumstances when the Croatian counties (regions) are simultaneously faced with problems related to post-war reconstruction, economic transition, industrial restructuring and future development. The paper will point out the main goals related to the development of the SME sector in Croatia as well as the importance of their development for particular categories of regions (counties affected by the war, border regions, industrial decline regions, etc.). The basic problems and needs of the entrepreneurs in these regions will be considered (on the basis of in depth surveys and interviews which are carried out in pilot regions). Furtherrmore, the paper will provide a survey of proposed policy measures aiming to encurage the start-up of new small firms, as well as further development of the already existing innovative industrial small firms - thus contributing to regional restructuring and development of Croatia's "problem regions".

Supporting memory and identity in older people: findings from a ‘Sandpit’ process

Identity in old age is challenged by physical changes, evolving roles within the family, and life transitions such as retirement. Supporting identity is therefore important in later life, and might be assisted by media technologies which allow people to reflect on their lives, record their personal histories and share these with family, friends and caregivers. This possibility was explored in two creative ‘Sandpits’ with older people as part of the SUS-IT project, funded by the New Dynamics of Ageing programme in the UK. Discussions were held with PC and non-PC user groups of retirement age to understand memory and identity practices and elicit reactions to three novel product concepts. These included a Reminiscing Radio for life review, a Story Lamp for associating spoken stories with photographs and memorabilia, and a pair of virtual reality Travel Glasses for transporting you back to a special place in the past. The main findings of these discussions will be presented, along with concepts generated by the participants in a re-design exercise. This paper will also show how the sandpits enabled older people to be involved in the design process by allowing them to shape early design concepts through exploring their own ideas and motivations

Fermionization, Convergent Perturbation Theory, and Correlations in the Yang-Mills Quantum Field Theory in Four Dimensions

We show that the Yang-Mills quantum field theory with momentum and spacetime cutoffs in four Euclidean dimensions is equivalent, term by term in an appropriately resummed perturbation theory, to a Fermionic theory with nonlocal interaction terms. When a further momentum cutoff is imposed, this Fermionic theory has a convergent perturbation expansion. To zeroth order in this perturbation expansion, the correlation function $E(x,y)$ of generic components of pairs of connections is given by an explicit, finite-dimensional integral formula, which we conjecture will behave as $$E(x,y) \sim |x - y|^{-2 - 2 d_G},$$ \noindent for $|x-y|>>0,$ where $d_G$ is a positive integer depending on the gauge group $G.$ In the case where $G=SU(n),$ we conjecture that $$d_G = {\rm dim}SU(n) - {\rm dim}S(U(n-1) \times U(1)),$$ \noindent so that the rate of decay of correlations increases as $n \to \infty.$Comment: Minor corrections of notation, style and arithmetic errors; correction of minor gap in the proof of Proposition 1.4 (the statement of the Proposition was correct); further remark and references adde