CAUSES AND CONSEQUENCES OF FOOD RETAILING INNOVATION IN DEVELOPING COUNTRIES: SUPERMARKETS IN VIETNAM

Modernization of food retailing in developing economies,focusing on the early stages of retail modernization in Vietnam is examined. This modernization represents innovation that is sought by the host country and that depends on knowledge transfer. Retail modernization has profound effects on the host country and its food system. Innovation at the consumption (retail) end of the food supply chain warrants attention similar to that devoted to knowledge transfer at the production (farming) end of the chain.Marketing, Research and Development/Tech Change/Emerging Technologies,

FOOD PROCESSING FIRMS AND FOREIGN PRODUCTION INCENTIVES

As the practice of a firm in one country owning production facilities in another has increased, several theories have developed to explain why production facilities do not always have local owners who would presumably be more familiar with local business conditions. A transaction cost explanation is that a firm may have intangible assets that are sought in another country but that cannot be economically sold on account of market failure. In such a case the firm's expansion into the foreign country may be the most economical way for the foreign country to gain access to those assets. A few studies have identified firm characteristics and firm-specific assets associated with the international growth of food firms. The present paper expands on this work by interviewing executives in two product areas (processed meats and preserved fruit/vegetable products) to discover which assets the executives perceive as important and nontransferable through market channels (and thus applicable to the transaction cost approach). The assets of product development expertise, process management knowledge, and reputation appear to be key intangible assets associated with foreign production. A regression analysis tests determinants of foreign production of the two product categories by 17 US firms in 9 global regions, yielding results consistent with the interviews. That is, the probability of having foreign production plants is significantly enhanced by higher total firm sales, being in the processed fruits and vegetables business as opposed to processed meats and locating in higher income, Western Hemisphere and European Countries.Agribusiness, Industrial Organization,

Spin and Statistics in Galilean Covariant Field Theory

The existence of a possible connection between spin and statistics is explored within the framework of Galilean covariant field theory. To this end fields of arbitrary spin are constructed and admissible interaction terms introduced. By explicitly solving such a model in the two particle sector it is shown that no spin and statistics connection can be established

On the unitary equivalence of absolutely continuous parts of self-adjoint extensions

The classical Weyl-von Neumann theorem states that for any self-adjoint operator $A$ in a separable Hilbert space $\mathfrak H$ there exists a (non-unique) Hilbert-Schmidt operator $C = C^*$ such that the perturbed operator $A+C$ has purely point spectrum. We are interesting whether this result remains valid for non-additive perturbations by considering self-adjoint extensions of a given densely defined symmetric operator $A$ in $\mathfrak H$ and fixing an extension $A_0 = A_0^*$. We show that for a wide class of symmetric operators the absolutely continuous parts of extensions $\widetilde A = {\widetilde A}^*$ and $A_0$ are unitarily equivalent provided that their resolvent difference is a compact operator. Namely, we show that this is true whenever the Weyl function $M(\cdot)$ of a pair $\{A,A_0\}$ admits bounded limits M(t) := \wlim_{y\to+0}M(t+iy) for a.e. $t \in \mathbb{R}$. This result is applied to direct sums of symmetric operators and Sturm-Liouville operators with operator potentials

Gamow shell-model calculations of drip-line oxygen isotopes

We employ the Gamow shell model (GSM) to describe low-lying states of the oxygen isotopes 24O and 25O. The many-body Schrodinger equation is solved starting from a two-body Hamiltonian defined by a renormalized low-momentum nucleon-nucleon (NN) interaction, and a spherical Berggren basis. The Berggren basis treats bound, resonant, and continuum states on an equal footing, and is therefore an appropriate representation of loosely bound and unbound nuclear states near threshold. We show that such a basis is necessary in order to obtain a detailed and correct description of the low-lying 1+ and 2+ excited states in 24O. On the other hand, we find that a correct description of binding energy systematics of the ground states is driven by proper treatment and inclusion of many-body correlation effects. This is supported by the fact that we get 25O unstable with respect to 24O in both oscillator and Berggren representations starting from a 22O core. Furthermore, we show that the structure of these loosely bound or unbound isotopes are strongly influenced by the 1S0 component of the NN interaction. This has important consequences for our understanding of nuclear stability.Comment: 5 pages, 3 figure

Perturbative Expansion in the Galilean Invariant Spin One-Half Chern-Simons Field Theory

A Galilean Chern-Simons field theory is formulated for the case of two interacting spin-1/2 fields of distinct masses M and M'. A method for the construction of states containing N particles of mass M and N' particles of mass M' is given which is subsequently used to display equivalence to the spin-1/2 Aharonov-Bohm effect in the N = N' =1 sector of the model. The latter is then studied in perturbation theory to determine whether there are divergences in the fourth order (one loop) diagram. It is found that the contribution of that order is finite (and vanishing) for the case of parallel spin projections while the antiparallel case displays divergences which are known to characterize the spin zero case in field theory as well as in quantum mechanics.Comment: 14 pages LaTeX, including 2 figures using eps

Panel collapse and its applications

We describe a procedure called panel collapse for replacing a CAT(0) cube complex $\Psi$ by a "lower complexity" CAT(0) cube complex $\Psi_\bullet$ whenever $\Psi$ contains a codimension-$2$ hyperplane that is extremal in one of the codimension-$1$ hyperplanes containing it. Although $\Psi_\bullet$ is not in general a subcomplex of $\Psi$, it is a subspace consisting of a subcomplex together with some cubes that sit inside $\Psi$ "diagonally". The hyperplanes of $\Psi_\bullet$ extend to hyperplanes of $\Psi$. Applying this procedure, we prove: if a group $G$ acts cocompactly on a CAT(0) cube complex $\Psi$, then there is a CAT(0) cube complex $\Omega$ so that $G$ acts cocompactly on $\Omega$ and for each hyperplane $H$ of $\Omega$, the stabiliser in $G$ of $H$ acts on $H$ essentially. Using panel collapse, we obtain a new proof of Stallings's theorem on groups with more than one end. As another illustrative example, we show that panel collapse applies to the exotic cubulations of free groups constructed by Wise. Next, we show that the CAT(0) cube complexes constructed by Cashen-Macura can be collapsed to trees while preserving all of the necessary group actions. (It also illustrates that our result applies to actions of some non-discrete groups.) We also discuss possible applications to quasi-isometric rigidity for certain classes of graphs of free groups with cyclic edge groups. Panel collapse is also used in forthcoming work of the first-named author and Wilton to study fixed-point sets of finite subgroups of $\mathrm{Out}(F_n)$ on the free splitting complex. Finally, we apply panel collapse to a conjecture of Kropholler, obtaining a short proof under a natural extra hypothesis.Comment: Revised according to referee comments. This version accepted in "Groups, Geometry, and Dynamics

Scattering matrices and Weyl functions

For a scattering system $\{A_\Theta,A_0\}$ consisting of selfadjoint extensions $A_\Theta$ and $A_0$ of a symmetric operator $A$ with finite deficiency indices, the scattering matrix \{S_\gT(\gl)\} and a spectral shift function $\xi_\Theta$ are calculated in terms of the Weyl function associated with the boundary triplet for $A^*$ and a simple proof of the Krein-Birman formula is given. The results are applied to singular Sturm-Liouville operators with scalar and matrix potentials, to Dirac operators and to Schr\"odinger operators with point interactions.Comment: 39 page