Some thoughts on GAIA and the sulfur cycle

The data hypothesis states that the composition, oxidation reduction state, and temperature of the troposphere are actively regulated by the biota for the biota. One of the early predictions of the Gaia hypothesis was that there should be a sulfur compound made by the biota in the oceans. It would need to be stable enough against oxidation in water to allow its transfer to the air. Either the sulfur compound itself or its atmospheric oxidation product would have to return sulfur from the sea to the land surfaces. The most likely candidate for this role was dimethyl sulfide. Another sulfur compound of interest from a Gaian viewpoint CS2 (carbon disulfide) is discussed. Theories on the production of dimethyl sulfide and carbon disulfide related to the Gaian hypothesis are examined

Martian atmospheric compositional analysis- its biological significance first quarterly progress report, 15 may - 15 aug. 1965

Biological significance of Martian atmospheric compositional analysis, and life detection studies of chemical free energy in surface matte

Spectral Evolution of an Earth-Like Planet

We have developed a characterization of the geological evolution of the Earths atmosphere and surface in order to model the observable spectra of an Earth-like planet through its geological history. These calculations are designed to guide the interpretation of an observed spectrum of such a planet by future instruments that will characterize exoplanets. Our models focus on spectral features that either imply habitability or are required for habitability. These features are generated by H2O, CO2, CH4, O2, O3, N2O, and vegetation-like surface albedos. We chose six geological epochs to characterize. These epochs exhibit a wide range in abundance for these molecules, ranging from a CO2 rich early atmosphere, to a CO2/CH4-rich atmosphere around 2 billion years ago to a present-day atmosphere. We analyzed the spectra to quantify the strength of each important spectral feature in both the visible and thermal infrared spectral regions, and the resolutions required to unambiguously observe the features for each epoch. We find a wide range of spectral resolutions required for observing the different features. For example, H2O and O3 can be observed with relatively low resolution, while O2 and N2O require higher resolution. We also find that the inclusion of clouds in our models significantly affects both the strengths and resolutions required to observe all spectral features.Comment: 34 pages, 24 fig, pdf, ApJ, TB

Random replicators with high-order interactions

We use tools of the equilibrium statistical mechanics of disordered systems to study analytically the statistical properties of an ecosystem composed of N species interacting via random, Gaussian interactions of order p >= 2, and deterministic self-interactions u <= 0. We show that for nonzero u the effect of increasing the order of the interactions is to make the system more cooperative, in the sense that the fraction of extinct species is greatly reduced. Furthermore, we find that for p > 2 there is a threshold value which gives a lower bound to the concentration of the surviving species, preventing then the existence of rare species and, consequently, increasing the robustness of the ecosystem to external perturbations.Comment: 7 pages, 4 Postscript figure

Tracer concentration profiles measured in central London as part of the REPARTEE campaign

There have been relatively few tracer experiments carried out that have looked at vertical plume spread in urban areas. In this paper we present results from two tracer (cyclic perfluorocarbon) experiments carried out in 2006 and 2007 in central London centred on the BT Tower as part of the REPARTEE (Regent’s Park and Tower Environmental Experiment) campaign. The height of the tower gives a unique opportunity to study vertical dispersion profiles and transport times in central London. Vertical gradients are contrasted with the relevant Pasquill stability classes. Estimation of lateral advection and vertical mixing times are made and compared with previous measurements. Data are then compared with a simple operational dispersion model and contrasted with data taken in central London as part of the DAPPLE campaign. This correlates dosage with non-dimensionalised distance from source. Such analyses illustrate the feasibility of the use of these empirical correlations over these prescribed distances in central London

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Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23372/1/0000316.pd

Higher dimensional gravity invariant under the Poincare group

It is shown that the Stelle-West Grignani-Nardelli-formalism allows, both when odd dimensions and when even dimensions are considered, constructing actions for higher dimensional gravity invariant under local Lorentz rotations and under local Poincar\`{e} translations. It is also proved that such actions have the same coefficients as those obtained by Troncoso and Zanelli in ref. Class. Quantum Grav. 17 (2000) 4451.Comment: 7 pages, Latex, accepted in Phys. Rev.

Normal frames and the validity of the equivalence principle

We investigate the validity of the equivalence principle along paths in gravitational theories based on derivations of the tensor algebra over a differentiable manifold. We prove the existence of local bases, called normal, in which the components of the derivations vanish along arbitrary paths. All such bases are explicitly described. The holonomicity of the normal bases is considered. The results obtained are applied to the important case of linear connections and their relationship with the equivalence principle is described. In particular, any gravitational theory based on tensor derivations which obeys the equivalence principle along all paths, must be based on a linear connection.Comment: 14 pages, LaTeX 2e, the package amsfonts is neede

Analysing Charges in even dimensions

Lanczos-Lovelock theories of gravity, in its first order version, are studied on asymptotically locally anti de Sitter spaces. It is shown that thermodynamics satisfies the standard behavior and an expression for entropy is found for this formalism. Finally a short analysis of the algebra of conserved charges is displayed

Preparation and characterisation of high-density ionic liquids incorporating halobismuthate anions

A range of ionic liquids containing dialkylimidazolium cations and halobismuthate anions ([BiBrxClyIz]− and [Bi2BrxClyIz]−) were synthesised by combining dialkylimidazolium halide ionic liquids with bismuth(III) halide salts. The majority were room temperature liquids, all with very high densities. The neat ionic liquids and their mixtures with 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide were characterised using Densitometry, Viscometry, NMR Spectroscopy, Electrospray Ionisation Mass Spectrometry (ESI), Liquid Secondary Ion Mass Spectrometry (LSIMS), Matrix-assisted Laser Desorption/Ionization Mass Spectrometry (MALDI), X-Ray Photoelectron Spectroscopy (XPS) and Thermogravimetric Analysis (TGA), to establish their speciation and suitability for high-temperature applications