Unconstrained Variables and Equivalence Relations for Lattice Gauge Theories

We write the partition function for a lattice gauge theory, with compact gauge group, exactly in terms of unconstrained variables and show that, in the mean field approximation, the dynamics of pure gauge theories, invariant under compact, continuous,groups of rank 1 is the same for all. We explicitly obtain the equivalence for the case of SU(2) and U(1) and show that it obtains, also, if we consider saddle point configurations that are not,necessarily, uniform, but only proportional to the identity for both groups. This implies that the phase diagrams of the (an)isotropic SU(2) theory and the (an)isotropic U(1) theory in any dimension are identical, within this approximation, up to a re-evaluation of the numerical values of the coupling constants at the transitions. Only nonuniform field configurations, that, also, belong to higher dimensional representations for Yang--Mills fields, will be able to p robe the difference between them. We also show under what conditions the global symmetry of an anisotropic term in the lattice action can be promoted to a gauge symmetry of the theory on layers and point out how deconstruction and flux compactification scenaria may thus be studied on the lattice.Comment: 14 pages, LateX2e. Expanded presentation of equivalence relation. Added discussion on how the global symmetry of the anisotropic term can be promoted to a gauge symmetry on a laye

Anomaly cancellation for anisotropic lattice fields with extra dimensions

The current flow from the bulk is due to the anomaly on the brane-but the absence of current flow is not, necessarily, due to anomaly cancellation, but to the absence of the chiral zero modes themselves, due to the existence of the layered phase. This can be understood in terms of the difference between the Chern-Simons terms in three and five dimensions. Thus the anomaly cancellation in four dimensions, which is essential for shielding the boundary from quantum effects within the bulk, makes sense only along the transition line between the layered and the Coulomb phase, which, in turn, requires the presence of a compact U(1) factor for the gauge group.Comment: 6 pages, 4 figures, LaTeX2e, uses PoS. Contribution to The XXVII International Symposium on Lattice Field Theory - LAT2009, July 26-31 2009,Peking University, Beijing, Chin

Second Order Phase Transition in Anisotropic Lattice Gauge Theories with Extra Dimensions

Field theories with extra dimensions live in a limbo. While their classical solutions have been the subject of considerable study, their quantum aspects are difficult to control. A special class of such theories are anisotropic gauge theories. The anisotropy was originally introduced to localize chiral fermions. Their continuum limit is of practical interest and it will be shown that the anisotropy of the gauge couplings plays a crucial role in opening the phase diagram of the theory to a new phase, that is separated from the others by a second order phase transition. The mechanism behind this is generic for a certain class of models, that can be studied with lattice techniques. This leads to new perspectives for the study of quantum effects of extra dimensions.Comment: 7 pages, 1 figure. Uses PoS.cls. Contribution to The XXVIII International Symposium on Lattice Filed Theory, June 14-19,2010,Villasimius, Sardinia Ital

The Spirit Moves

The Charismatic Movement represents one of the most significant developments in the life of the Church today. During the past decade and a half it has rapidly spread through the “mainline” denominational churches. As a result, a great deal of misunderstanding and tension has developed. Everything from devil worship to divisions in the Church has been attributed to the Holy Spirit Movement. Since there is much misunderstanding, prejudice and ignorance about the Holy Spirit Movement and the Holy Spirit moving, the following is presented which centres attention on the Biblical basis for this movement

Spectropolarimetric signatures of Earth-like extrasolar planets

We present results of numerical simulations of the flux (irradiance), F, and the degree of polarization (i.e. the ratio of polarized to total flux), P, of light that is reflected by Earth-like extrasolar planets orbiting solar-type stars, as functions of the wavelength (from 0.3 to 1.0 micron, with 0.001 micron spectral resolution) and as functions of the planetary phase angle. We use different surface coverages for our model planets, including vegetation and a Fresnel reflecting ocean, and clear and cloudy atmospheres. Our adding-doubling radiative transfer algorithm, which fully includes multiple scattering and polarization, handles horizontally homogeneous planets only; we simulate fluxes and polarization of horizontally inhomogeneous planets by weighting results for homogeneous planets. Like the flux, F, the degree of polarization, P, of the reflected starlight is shown to depend strongly on the phase angle, on the composition and structure of the planetary atmosphere, on the reflective properties of the underlying surface, and on the wavelength, in particular in wavelength regions with gaseous absorption bands. The sensitivity of P to a planet's physical properties appears to be different than that of F. Combining flux with polarization observations thus makes for a strong tool for characterizing extrasolar planets. The calculated total and polarized fluxes will be made available through the CDS.Comment: 31 pages text, 17 figures, 1 table Submitted to A&

A Process Model of Locational Change in Entrepreneurial Firms: An Evolutionary Perspective

How do changes in the spatial organization of entrepreneurial firms come about? This paper provides a conceptualisation of the process of locational change. A process model of locational change is constructed on the basis of an empirical study of 109 locational events during the life course of 25 young firms in knowledge intensive sectors (knowledge services and biomedicals). This process model of locational change maps both internal and external variation and selection processes. This model contributes to the development of a causal process theory of the spatial development of (new) firms.Location;Decision-Making;Entrepreneurial Firms;Evolutionary Theory;Process Models

A Process Model of Locational Change in Entrepreneurial Firms: An Evolutionary Perspective

How do changes in the spatial organization of entrepreneurial firms come about? This paper provides a conceptualisation of the process of locational change. A process model of locational change is constructed on the basis of an empirical study of 109 locational events during the life course of 25 young firms in knowledge intensive sectors (knowledge services and biomedicals). This process model of locational change maps both internal and external variation and selection processes. This model contributes to the development of a causal process theory of the spatial development of (new) firms.location, entrepreneurial firms, evolutionary theory, decision-making, process models

Why Butterflies Don’t Leave - Spatial development of new firms

There is an emerging interest in the local conditions of entrepreneurship and firm dynamics. The often-cited examples of entrepreneurship in successful regional clusters show that entrepreneurship is really a localized phenomenon, which seems to be at odds with the increased globalization of economic activity, in which firms are said to be relatively footloose and easily become multinational enterprises. Other authors have noted that in spite of information and communication technologies, the vital importance of face-to-face contact cannot be discounted (Hallowell, 1999); as Leamer and Storper (2001: 641) observe, the Internet “allows long distance ‘conversations’ but not ‘handshakes’ ”. Next to controversies concerning the role of the global and the local for firms (cf. West, 2002), there is a general weakness in the theory of the firm concerning the analysis of (new) firm dynamics. According to Geroski (2001) the theory of the firm in economics is preoccupied by the question of why firms exist, and it is both very narrow and very static. Further work in this area might be usefully extended to address the question of how firms grow and develop over time, and this, in turn, will force people to think through issues associated with what makes change difficult for firms. We will deal with these issues in a discussion of evolutionary theories of the firm in general, and specific theories of the entrepreneurial firm and the multinational firm in particular, and regional cluster approaches. The central question in this paper is: “Are there necessary interactions between the development of entrepreneurial firms and their spatial organization over time?”. We will deal with this question in a longitudinal way, i.e. analyze the development of entrepreneurial firms and the changes in their spatial organization during their life course. The development of entrepreneurial firms involves the firm–founding (Shane and Khurana, 2003) and the subsequent early growth (Garnsey, 1998) of the firm. These firms are not self-employed (anymore), and mostly not (yet) a multinational corporation; in a sense they are neither small nor large, but dynamic, turning from a caterpillar into a butterfly (cf. Penrose 1995), and are central to dynamics in the new, or entrepreneurial economy (Bresnahan et al., 2001; Audretsch and Thurik, 2003). The empirical part of this study is based on comparative case studies (Eisenhardt, 1989; Yin, 2003) of 25 entrepreneurial firms, and 8 micro firms in four propulsive industries, namely professional business services, biomedicals, graphics-media, and shipbuilding. The spatial organization of firms consists of the dynamic constructs of locational adjustment and locational flexibility, which refer to the adjustment of the spatial organization of firms outside the headquarter (the location at which the entrepreneur/owner-manager executes his activities) of the firm and to the flexibility of the location of the headquarter respectively. With these two dimensions the tendency towards concentration or dispersion of the firm can be observed (cf. Storper, 1997, p.299-300). The spatial development of new firms consists of the sequence of locational events. Locational events refer to the changes in the state of the spatial organization of firms. The different types of locational events were coded in order to find typical sequences of locational events (cf. Abbott, 1995). Concrete events have been studied that may be unique to some extent. However, “[t]he focus is not on how or why something happened but on how or why something happens” (Mohr, 1982, p.5). We are looking for mechanisms that explain the spatial development of new firms. The abstract knowledge resulting from insight into these mechanisms may be more generally applicable. We have used a combination of quantitative and qualitative methods. We registered the general characteristics of the entrepreneur, his network relations, the firm (its strategy, structure and capabilities), inter-organizational relations, and their locations. The qualitative method involved a life history of the firm as told by the entrepreneur (Van Geenhuizen et al., 1992). This life history has been explicated with a critical incident technique (Tjosvold and Weicker, 1993; Chell and Pittaway, 1998). The fieldwork involved the study of how (location) decisions are actually made during the life course of emerging firms and how they affect and are affected by the firms’ development in general. Next to the quantitative data derived from the interviews other data from company archives, the press and other media was collected. The empirical study shows that capabilities more often seem to constrain (as a place-specific sunk cost) than to enable the spatial flexibility of entrepreneurial firms. However, certain organizational capabilities have to be built in order to become multilocational, especially on the interregional and international levels. The inter-organizational networks in regional clusters are hardly relevant in the explanation of the dynamics in the spatial organization of entrepreneurial firms. They only seem to constrain the location behavior in the early phases of entrepreneurial firms, when radical changes in the spatial organization are almost never considered at all.