A GAS OF D-INSTANTONS

A D-instanton is a space-time event associated with world-sheet boundaries that contributes non-perturbative effects of order $e^{-const/\kappa}$ to closed-string amplitudes. Some properties of a gas of D-instantons are discussed in this paper.Comment: 11 Pages and 3 figures in uuencoded fil

[Review of] Francis Paul Prucha, Indian-White Relations in the United States: A Bibliography of Works Published, 1975-1980

This volume is the long-awaited supplement to Francis Paul Prucha\u27s Bibliographical Guide to the History of Indian-White Relations in the United States, published by the University of Chicago Press in 1977. That work, which contained 9705 items, was complete to 1975. The supplement, with 3400 titles, covers the historical literature made available between 1975 and 1980. Organized into fifteen subject divisions and excellently cross-referenced with a thirty-six page index, the supplement continues the same high quality of Prucha\u27s previous efforts to bring some useable order to the bewildering complexity of American Indian historiography

The radial distributions of a heavy-light meson on a lattice

In an earlier work, the charge (vector) and matter (scalar) radial distributions of heavy-light mesons were measured in the quenched approximation on a 16^3 times 24 lattice with a quark-gluon coupling of 5.7, a lattice spacing of 0.17 fm, and a hopping parameter corresponding to a light quark mass about that of the strange quark. Several improvements are now made: 1) The configurations are generated using dynamical fermions with a quark-gluon coupling of 5.2 (a lattice spacing of 0.14 fm); 2) Many more gauge configurations are included (78 compared with the earlier 20); 3) The distributions at many off-axis, in addition to on-axis, points are measured; 4) The data-analysis is much more complete. In particular, distributions involving excited states are extracted. The exponential decay of the charge and matter distributions can be described by mesons of mass 0.9+-0.1 and 1.5+-0.1 GeV respectively - values that are consistent with those of vector and scalar qqbar-states calculated directly with the same lattice parameters.Comment: 3 pages, 4 figures, Lattice2002(heavyquark

Improving market intelligence for organic horticulture in Wales

The organic market in the UK reached a value of £1.015 billion during the 2002/2003 financial year. The market for organic food and drink in Wales and the surrounding counties is estimated to account for 6.3 per cent of this, a total of £64 million. Assuming the proportion of sales of organic fruit and vegetables in Wales is the same as the UK as a whole then the market for organic fruit and vegetables in Wales can be valued at £20.5 million for the financial year 2002/03. The area of fully organic horticultural land in Wales in April 2003 was 513 hectares with 102 producers involved in organic fruit and vegetable production. Of these producers, over 60 per cent were mixed farms encompassing livestock and/or cereals alongside horticulture. The estimated farm-gate value of Welsh produced organic fruit and vegetables was £1.8 million, approaching 5 per cent of the total UK farm-gate value of £43.96 million. Organic horticultural production accounts for a significant proportion - 10 per cent - of the total horticultural land in Wales. In comparison, organic horticulture in the UK as a whole accounts for just 4 per cent of the total horticultural land. Interviews with Welsh growers identified a number of key challenges facing them including market access, lack of producer co-operation, increased competition (particularly from within the UK) and availability of labour. At the beginning of 2003, 103 licensed organic processing operations were operating in Wales with approximately one-third handling fruit and vegetables. The main constraints to increasing the utilisation of domestic produce were identified as continuity, quality, accessibility and reliability of supply. Key recommendations to help overcome many of the challenges identified are included in Chapter 6 - Conclusions and Recommendations. Fruit and vegetables are a key entry point for consumers beginning to buy organic food. Welsh consumers are less ‘put-off’ by the price of organic food than consumers across the UK as a whole. Supporting the local farmers is particularly important to the Welsh consumer, with 35 per cent of the Welsh organic buying public stating that it was important to support local farmers, compared to 16 per cent in the UK overall

On strict passivity and its application to interpolation and Hl control

The authors introduce the L2-system and derive necessary and sufficient conditions for these systems to be strictly passive. Strictly passive L2-systems are characterized as having a representation in terms of a co-J-lossless matrix. A state space proof is developed and provides a Riccati equation characterization of a strictly passive L 2-system, as well as a formula for the co-J-lossless matrix representation. Applications to Nevanlinna-Pick interpolation and an H∞ filtering problem are considere

Anomalous Creation of Branes

In certain circumstances when two branes pass through each other a third brane is produced stretching between them. We explain this phenomenon by the use of chains of dualities and the inflow of charge that is required for the absence of chiral gauge anomalies when pairs of D-branes intersect.Comment: 7 pages, two figure