Phosphorus Management on ‘Extensive' Organic Farms with Infertile Soils

Two case-study farms with negative P balances maintained acceptable productivity without fertilisers, apparently by ‘mining’ ‘available’ P reserves in surface and subsoil. The question for these organic farms is ‘how long before fertiliser is needed?’ With six farms on lower-fertility, weakly acidic to alkaline soils and modest rainfall (380-580 mm/yr), low productivity was related to P deficiency despite positive P balances from using allowable fertilisers. Useful supplies of compost or manure were unavailable. Until effective allowable fertilisers or microbial inoculants have been developed, there is a case for using soluble forms of P fertiliser on soils where soil-solution P is low and soil P-sorption is high, so that additions of soluble P ‘feed the soil, not the plant’

Transverse Galaxy Velocities from Multiple Topological Images

The study of the kinematics of galaxies within clusters or groups has the limitation that only one of the three velocity components and only two of the three spatial components of a galaxy position in six-dimensional phase space can normally be measured. However, if multiple topological images of a cluster exist, then the radial positions and sky plane mean velocities of galaxies in the cluster may also be measurable from photometry of the two cluster images. The vector arithmetic and principles of the analysis are presented. These are demonstrated by assuming the suggested topological identification of the clusters RX J1347.5-1145 and CL 09104+4109 to be correct and deducing the sky-plane relative velocity component along the axis common to both images of this would-be single cluster. Three out of four of the inferred transverse velocities are consistent with those expected in a rich cluster. A control sample of random `common' sky-plane axes, independent of the topological hypothesis, implies that this is not surprising. This shows that while galaxy kinematics are deducible from knowledge of cosmological topology, it is not easy to use them to refute a specific candidate manifold.Comment: 13 pages, 7 figures, accepted for MNRA

Detecting the Cosmic Gravitational Wave Background with the Big Bang Observer

The detection of the Cosmic Microwave Background Radiation (CMB) was one of the most important cosmological discoveries of the last century. With the development of interferometric gravitational wave detectors, we may be in a position to detect the gravitational equivalent of the CMB in this century. The Cosmic Gravitational Background (CGB) is likely to be isotropic and stochastic, making it difficult to distinguish from instrument noise. The contribution from the CGB can be isolated by cross-correlating the signals from two or more independent detectors. Here we extend previous studies that considered the cross-correlation of two Michelson channels by calculating the optimal signal to noise ratio that can be achieved by combining the full set of interferometry variables that are available with a six link triangular interferometer. In contrast to the two channel case, we find that the relative orientation of a pair of coplanar detectors does not affect the signal to noise ratio. We apply our results to the detector design described in the Big Bang Observer (BBO) mission concept study and find that BBO could detect a background with $\Omega_{gw} > 2.2 \times 10^{-17}$.Comment: 15 pages, 12 Figure

Forward Modeling of Space-borne Gravitational Wave Detectors

Planning is underway for several space-borne gravitational wave observatories to be built in the next ten to twenty years. Realistic and efficient forward modeling will play a key role in the design and operation of these observatories. Space-borne interferometric gravitational wave detectors operate very differently from their ground based counterparts. Complex orbital motion, virtual interferometry, and finite size effects complicate the description of space-based systems, while nonlinear control systems complicate the description of ground based systems. Here we explore the forward modeling of space-based gravitational wave detectors and introduce an adiabatic approximation to the detector response that significantly extends the range of the standard low frequency approximation. The adiabatic approximation will aid in the development of data analysis techniques, and improve the modeling of astrophysical parameter extraction.Comment: 14 Pages, 14 Figures, RevTex

Social networks in east Cleveland: a study of powerlessness and non-participation

This thesis is based on material gathered as part of a larger, multi-methodological study of public participation in Structure Planning in Cleveland County in the North East of England. The variations in local responses to planning policies were investigated through the use of the social networks approach, in which the interaction between individuals and sets of individuals was the main focus of the analysis. The case-study in this thesis covers an area in which there was little, if any, response to the Structure Plans. It is, therefore, primarily an explanation of non-participation. The former "ironstone mining settlements of the Skelton and Brotton area of East Cleveland are marked by declining employment opportunities, poor roads and facilities, and much old and obsolete housing. The image of dereliction, fragmentation and deprivation is reinforced by the planners' treatment of the area, both in the plans and in the way that public participation in the area was managed. Analysis of interaction in networks shows some inter- penetration of group membership, but no coherent, enduring involvement by participators from more than one village together, raising questions of cohesion and conflict. Within the context of fragmentation and competition between villages, the impact of major demolition and renovation schemes is assessed. The explanation of non-participation in a situation of clear inequality and disadvantage necessitates the use of power theory of a more radical type than that which has usually been applied to the inherently political process of planning. A theoretical frame work adequate to deal with the powerlessness of a population whose interests are adversely affected by those in power, is a modified version of Lukes' three-dimensional approach. Ideological factors such as deference can thus be related to the acquiescence found

Comment on "Gravity Waves, Chaos, and Spinning Compact Binaries"

In this comment, I argue that chaotic effects in binary black hole inspiral will not strongly impact the detection of gravitational waves from such systems.Comment: 1 page, comment on gr-qc/991004

Prospects for observing ultra-compact binaries with space-based gravitational wave interferometers and optical telescopes

Space-based gravitational wave interferometers are sensitive to the galactic population of ultra-compact binaries. An important subset of the ultra-compact binary population are those stars that can be individually resolved by both gravitational wave interferometers and electromagnetic telescopes. The aim of this paper is to quantify the multi-messenger potential of space-based interferometers with arm-lengths between 1 and 5 Gm. The Fisher Information Matrix is used to estimate the number of binaries from a model of the Milky Way which are localized on the sky by the gravitational wave detector to within 1 and 10 square degrees and bright enough to be detected by a magnitude limited survey. We find, depending on the choice of GW detector characteristics, limiting magnitude, and observing strategy, that up to several hundred gravitational wave sources could be detected in electromagnetic follow-up observations.Comment: 6 pages, 3 figures Updated to include new results. Submitted to MNRA

Flame detector operable in presence of proton radiation

A detector of ultraviolet radiation for operation in a space vehicle which orbits through high intensity radiation areas is described. Two identical ultraviolet sensor tubes are mounted within a shield which limits to acceptable levels the amount of proton radiation reaching the sensor tubes. The shield has an opening which permits ultraviolet radiation to reach one of the sensing tubes. The shield keeps ultraviolet radiation from reaching the other sensor tube, designated the reference tube. The circuitry of the detector subtracts the output of the reference tube from the output of the sensing tube, and any portion of the output of the sensing tube which is due to proton radiation is offset by the output of the reference tube. A delay circuit in the detector prevents false alarms by keeping statistical variations in the proton radiation sensed by the two sensor tubes from developing an output signal