Mass Wasting In Planetary Environments: Implications For Seismicity

On Earth, mass wasting events such as rock falls and landslides are well known conse-quences of seismic activity. Through a variety of re-mote sensing techniques, tectonic faults have been pos-itively identified on all four of the inner planets, Earth's Moon, several outer planet satellites, and aster-oids. High-resolution imaging has furthermore ena-bled positive identification of mass wasting events on many of these bodies. On Mars, it has been suggested that fallen boulders may be indicative of pale-omarsquakes. On the Moon, meteor impacts and moonquakes have likewise been suggested as potential triggering mechanisms for mass wasting. Indeed, we know from the Apollo era that the Moon experienc-es a wide variety of seismicity. Seismicity estimates play an important role in creat-ing regional geological characterizations, which are useful not only for understanding a planet's formation and evolution, but also of key importance to site selec-tion for landed missions. Here we investigate the re-gional effects of seismicity in planetary environments with the goal of determining whether surface features such as landslides and boulder trails on the Moon, Mars, and Mercury could be triggered by fault motion. We attempt to quantify the amount of near-source ground shaking necessary to mobilize the mate-rial observed in various instances of mass wasting

Mass Wasting on the Moon: Implications for Seismicity

Introduction: Seismicity estimates play an important role in creating regional geological characterizations, which are useful for understanding a planet's formation and evolution, and of key importance to site selection for landed missions. Here we investigate the regional effects of lunar seismicity with the goal of determining whether surface features such as landslides and boulder trails on the Moon are triggered by fault motion

M Theory from World-Sheet Defects in Liouville String

We have argued previously that black holes may be represented in a D-brane approach by monopole and vortex defects in a sine-Gordon field theory model of Liouville dynamics on the world sheet. Supersymmetrizing this sine-Gordon system, we find critical behaviour in 11 dimensions, due to defect condensation that is the world-sheet analogue of D-brane condensation around an extra space-time dimension in M theory. This supersymmetric description of Liouville dynamics has a natural embedding within a 12-dimensional framework suggestive of F theory.Comment: 17 pages LATEX, 1 epsf figure include

Modular Invariance and Uniqueness of Conformal Characters

We show that the conformal characters of various rational models of W-algebras can be already uniquely determined if one merely knows the central charge and the conformal dimensions. As a side result we develop several tools for studying representations of SL(2,Z) on spaces of modular functions. These methods, applied here only to certain rational conformal field theories, may be useful for the analysis of many others.Comment: 21 pages (AMS TeX), BONN-TH-94-16, MPI-94-6

Fermionic representations for characters of M(3,t), M(4,5), M(5,6) and M(6,7) minimal models and related Rogers-Ramanujan type and dilogarithm identities

Characters and linear combinations of characters that admit a fermionic sum representation as well as a factorized form are considered for some minimal Virasoro models. As a consequence, various Rogers-Ramanujan type identities are obtained. Dilogarithm identities producing corresponding effective central charges and secondary effective central charges are derived. Several ways of constructing more general fermionic representations are discussed.Comment: 14 pages, LaTex; minor correction

A new approximation scheme in quantum mechanics

An approximation method which combines the perturbation theory with the variational calculation is constructed for quantum mechanical problems. Using the anharmonic oscillator and the He atom as examples, we show that the present method provides an efficient scheme in estimating both the ground and the excited states. We also discuss the limitations of the present method.Comment: 14pages, to be published in Eur. J. Phy

Social and economical evaluation of innovative alley coppice systems mixing timber trees with bioenergy wood crops in agroforestry systems

PosterAlley coppice (AC) is an innovative agroforestry system where high value timber trees in lines are intercropped with bioenergy short rotation coppice (SRC). AC potentially provides several production and environmental benefits, although so far these are poorly investigated. Thus, research on farmer interest in AC systems, and preliminary economic evaluations, have been made on the AgroCop European project (www.agrocop.com). A questionnaire was conducted with farmers in Italy to identify and assess their interests and concerns regarding AC systems. Farmers appeared to be familiar with managing forest plantations as species mixtures and the value of fuelwood. However, the value of the timber and biomass produced during the rotation appeared to be farmers’ main source of uncertainty, with no clear idea of what demand there would be for both wood products, and they assigned a higher rank to the importance of environmental benefits (biodiversity, landscape, soil fertility improvement). This indicated that there was a need to study the economic performance of the AC system developing two tools: a simplified economic calculator for stakeholders, that can estimate and compare net present value (NPV) of different AC systems, and a more complex model, adapting FarmSAFE. Biophysical data was generated using LERSAFE. Wood chips from the SRC component were found to have a low market value, and AC profitability depends mostly on the timber trees, with the essential need to optimize revenue from the valuable timber, especially by maximizing its quality. Therefore, the SRC component has an important role to play in increasing the quality of the valuable timber by improving timber tree form, reducing the costs of management operations and for giving a revenue during the growth of standard trees. AC could be an innovative option for timber and bioenergy production, integrating some of the advantages that are characteristic of agroforestry systems into mixed tree plantations

Free tensor multiplets and strings in spontaneously broken six-dimensional (2,0) theory

We first review the representations of the six-dimensional (2,0) superalgebra on a free tensor multiplet and on a free string. We then construct a supersymmetric Lagrangian describing a free tensor multiplet. (It also includes a decoupled anti self-dual part of the three-form field strength.) This field theory is then rewritten in variables appropriate for analyzing a situation where the R-symmetry is spontaneously broken by the vacuum expectation values of the scalar moduli fields. Finally, we construct a supersymmetric and kappa-symmetric action for a free string.Comment: 15 pages, LaTe

Monopoles and Instantons on Partially Compactified D-Branes

Motivated by the recent D-brane constructions of world-volume monopoles and instantons, we study the supersymmetric SU(N) Yang-Mills theory on $S^1 \times R^{3+1}$, spontaneously broken by a Wilson loop. In addition to the usual N-1 fundamental monopoles, the N-th BPS monopole appears from the Kaluza-Klein sector. When all N monopoles are present, net magnetic charge vanishes and the solution can be reinterpreted as a Wilson-loop instanton of unit Pontryagin number. The instanton/multi-monopole moduli space is explicitly constructed, and seen to be identical to a Coulomb phase moduli space of a U(1)^N gauge theory in 2+1 dimensions related to Kronheimer's gauge theory of SU(N) type. This extends the results by Intriligator and Seiberg to the finite couplings that, in the infrared limit of Kronheimer's theory, the Coulomb phase parameterizes a centered SU(N) instanton. We also elaborate on the case of restored SU(N) symmetry.Comment: LaTex, 18pages, no figur