Three Dimensional Gravity From SU(2) Yang-Mills Theory in Two Dimensions

We argue that two dimensional classical SU(2) Yang-Mills theory describes the embedding of Riemann surfaces in three dimensional curved manifolds. Specifically, the Yang-Mills field strength tensor computes the Riemannian curvature tensor of the ambient space in a thin neighborhood of the surface. In this sense the two dimensional gauge theory then serves as a source of three dimensional gravity. In particular, if the three dimensional manifold is flat it corresponds to the vacuum of the Yang-Mills theory. This implies that all solutions to the original Gauss-Codazzi surface equations determine two dimensional integrable models with a SU(2) Lax pair. Furthermore, the three dimensional SU(2) Chern-Simons theory describes the Hamiltonian dynamics of two dimensional Riemann surfaces in a four dimensional flat space-time

A bibliography of Lake Kariba 1987-1994

The bibliography contains some 116 citations, including unpublished reports and manuscripts, regarding Lake Kariba. Most of the reports are from the Zambia/Zimbabwe SADC Fisheries and Lake Kariba Fisheries Research Institute. The citations are listed in alphabetical order according to author

Formation of Amorphous Metal By Hypervelocity Impact

The Center for Electromechanics at The University of Texas at Austin has investigated the use of an electromagnetic railgun accelerator for the deposition of non-crystalline metals. The two main objectives of the study were to produce non-crystalline metal deposits in single thin layers (˷ 25lJm thick) and to determine the feasibility of building thicker layers by making multiple deposits. Deposits have been analyzed using a variety of techniques, including electrical resistivity and resistivity ratio, x-ray diffraction, and transmission electron microscopy. Differential scanning calorimetry was carried out at Battelle Columbus Laboratories. The measurements show that CEM-UT -has produced non-crystalline Fe78B13Si9 deposits. Single and multiple-layer non-crystalline deposits with thicknesses of up to 36 µm have been produced, and the upper thickness limit of the technique has not yet been determined.Center for Electromechanic

Composting rapidly degrades DNA from genetically modified plants

Organic farmers are concerned about the use of genetically modified plants (GM plants) in conventional agriculture. The concern is mainly focused on the risk of spreading of pollen or seeds from GM plans to adjacent fields. There has been less focus on the environmental impact of exposing the soil to genetically modified DNA (i.e. transgenic DNA) from GM plants residues left in the field. Yet, the new EU directive on the deliberate release into the environment of genetically modified organisms (EU, 2001) requires a "description of post-release treatment methods for the genetically modified plant material including wastes"

An Economic Analysis of Agricultural Sustainability in Orissa

The development of a method for generating Sustainable Livelihood Security Index (SLSI) for agricultural sustainability and evaluating the existing status has been reported. Some measures have been suggested to promote sustainable agriculture of Orissa. This state has been selected since it faces wide inequality, improper management and over-exploitation of natural resources and explosion of population. These have created a threat to ecological balance and economic as well as social status of households in different districts of the state. The study of Ecological Security Index (ESI), Economic Efficiency Index (EEI) and Social Equity Index (SEI) has revealed that the agricultural systems of all districts display wide variations in their ecological and social equity aspects relative to their economic aspects. The districts with better SLSI ranks are often described as advanced districts and vice versa. Hence, SLSI has been found to reflect the picture of overall performance of a district in three dimensions of sustainability. On the basis of the overall performance of districts in terms of their SLSI, only eight districts in the state have an index value of more than 0.5, while thirteen districts have SLSI less than 0.4. Also, many districts of coastal Orissa have depicted better performance in agricultural sustainability in comparison to the districts of western Orissa as a whole. Some policy implications of SLSI approach have also been reported.Environmental Economics and Policy, Farm Management,

Seedless electroplating on patterned silicon

Nickel thin films have been electrodeposited without the use of an additional\ud seed layer, on highly doped silicon wafers. These substrates conduct\ud sufficiently well to allow deposition using a peripherical electrical contact on\ud the wafer. Films 2 μm thick have been deposited using a nickel sulfamate\ud bath on both n+- and p+-type silicon wafers, where a series of trenches with\ud different widths had been previously etched by plasma etching. A new,\ud reliable and simple procedure based on the removal of the native oxide layer\ud is presented which allows uniform plating of patterned substrates

Electron density stratification in two-dimensional structures tuned by electric field

A new kinetic instability which results in formation of charge density waves is proposed. The instability is of a purely classical nature. A spatial period of arising space-charge and field configuration is inversely proportional to electric field and can be tuned by applied voltage. The instability has no interpretation in the framework of traditional hydrodynamic approach, since it arises from modulation of an electron distribution function both in coordinate and energy spaces. The phenomenon can be observed in thin 2D nanostructures at relatively low electron density.Comment: 4 pages, 2 figure

Instabilities of Twisted Strings

A linear stability analysis of twisted flux-tubes (strings) in an SU(2) semilocal theory -- an Abelian-Higgs model with two charged scalar fields with a global SU(2) symmetry -- is carried out. Here the twist refers to a relative phase between the two complex scalars (with linear dependence on, say, the $z$ coordinate), and importantly it leads to a global current flowing along the the string. Such twisted strings bifurcate with the Abrikosov-Nielsen-Olesen (ANO) solution embedded in the semilocal theory. Our numerical investigations of the small fluctuation spectrum confirm previous results that twisted strings exhibit instabilities whose amplitudes grow exponentially in time. More precisely twisted strings with a single magnetic flux quantum admit a continuous family of unstable eigenmodes with harmonic $z$ dependence, indexed by a wavenumber $k\in[-k_{\rm m},k_{\rm m}]$. Carrying out a perturbative semi-analytic analysis of the bifurcation, it is found that the purely numerical results are very well reproduced. This way one obtains not only a good qualitative description of the twisted solutions themselves as well as of their instabilities, but also a quantitative description of the numerical results. Our semi-analytic results indicate that in close analogy to the known instability of the embedded ANO vortex a twisted string is also likely to expand in size caused by the spreading out of its magnetic flux.Comment: 27 pages, 18 figures. Typos corrected, references adde

SU3SU_3 coherent state operators and invariant correlation functions and their quantum group counterparts

Coherent state operators (CSO) are defined as operator valued functions on G=SL(n,C), homogeneous with respect to right multiplication by lower triangular matrices. They act on a model space containing all holomorphic finite dimensional representations of G with multiplicity 1. CSO provide an analytic tool for studying G invariant 2- and 3-point functions, which are written down in the case of $SU_3$. The quantum group deformation of the construction gives rise to a non-commutative coset space. We introduce a "standard" polynomial basis in this space (related to but not identical with the Lusztig canonical basis) which is appropriate for writing down $U_q(sl_3)$ invariant 2-point functions for representaions of the type $(\lambda,0)$ and $(0,\lambda)$. General invariant 2-point functions are written down in a mixed Poincar\'e-Birkhoff-Witt type basis.Comment: 33 pages, LATEX, preprint IPNO/TH 94-0

Renormalization group approach to Fermi Liquid Theory

We show that the renormalization group (RG) approach to interacting fermions at one-loop order recovers Fermi liquid theory results when the forward scattering zero sound (ZS) and exchange (ZS$'$) channels are both taken into account. The Landau parameters are related to the fixed point value of the ``unphysical'' limit of the forward scattering vertex. We specify the conditions under which the results obtained at one-loop order hold at all order in a loop expansion. We also emphasize the similarities between our RG approach and the diagrammatic derivation of Fermi liquid theory.Comment: 4 pages (RevTex) + 1 postcript file, everything in a uuencoded file, uses epsf (problem with the figure in the first version