Identification of Coulomb blockade and macroscopic quantum tunneling by noise

The effects of Macroscopic Quantum Tunneling (MQT) and Coulomb Blockade (CB) in Josephson junctions are of considerable significance both for the manifestations of quantum mechanics on the macroscopic scale and potential technological applications. These two complementary effects are shown to be clearly distinguishable from the associated noise spectra. The current noise is determined exactly and a rather sharp crossover between flux noise in the MQT and charge noise in the CB regions is found as the applied voltage is changed. Related results hold for the voltage noise in current-biased junctions.Comment: 6 pages, 3 figures, epl.cls include

Contribution of integrated farm management (IFM) to Defra objectives

A farming system comprises a complex of interrelated and interacting factors. Any study of an isolated part of the system will not provide adequate understanding of the behaviour of the entire system and interactions may be equally or more important than individual components. There is therefore a requirement for the development of integrated approaches and practices to help farming systems adapt to, eliminate or reduce the negative impacts of production on the environment. This must be achieved whilst maintaining the economic viability of the farm enterprise. Our analysis has confirmed that IFM techniques generally have far more beneficial than adverse effects on current Defra policy objectives. However, there are some notable ‘conflicts’ where a technique that has a large beneficial effect in one policy area has a large negative effect in another. Carbon footprinting is used to quantify the impact of some integrated farming practices

Sustainable production of organic wheat

The aim of the project is to use an ecological approach to analyse the interactions of a range of key agronomic variables in organic wheat production (wheat genotype, spatial arrangement of seed, seed density and wheat/white clover bi-cropping) to determine an optimal approach to improved and stabilised production. The fi rst set of data revealed that seedling competition was infl uenced by seed rate and drilling arrangement. Furthermore, the variety Hereward had increased emergence and establishment to Aristos. An interaction exists between wheat variety, seed rate and drilling arrangement on the level of canopy cover at different developmental stages – these factors are important for the suppression of weeds. The input of farmers in the selection of trial variables ensures results have a direct application to the industry. The results of yield and quality at harvest will provide further insights into the interaction of agronomic variables

Evolutionary breeding of healthy wheat: from plot to farm

Genetically diverse Composite Cross Populations (CCPs) may be useful in environmentally variable low-input systems as an alternative to pure line varieties. They are formed by hybridising lines with diverse evolutionary origins, bulking the F1 progeny, and allowing natural selection of the progeny in successive crop environments. CCPs derived from 10 high yielding parents (YCCPs), 12 high quality parents (QCCPs), or all 22 parents (YQCCPs), were grown at four sites (2 organic, 2 conventional) in the UK; they are currently (2006) in F5. The YCCPs out yielded the QCCPs, which had better quality characteristics. Although the CCPs performed within the range of the parents, the values obtained were often better than the mean of the parents. Some population samples are now being grown on farms and other sites in England, France, Germany and Hungary

The identification and production of varieties that increase the value of oats as a profitable component of organic production

Two experiments, one comprising husked, and the other naked, oats were established at Wakelyns Agroforestry, Suffolk in October 2004 to determine traits and varieties of oats suited to organic systems, and whether growing variety mixtures conferred any advantage. Unselected F2 breeding lines were also included for selection. Husked varieties had relatively higher yields; this may have been partly the result of poor establishment in the naked varieties. Variety height was found to be an important characteristic; tall oat varieties out-yielded the dwarfs. Two of the three variety mixtures containing the naked oat variety Expression yielded 8 and 9 % higher than the average of the component varieties. The data will be verified in the second year of replicated trials (2005/06), which will include the best performing husked and naked varieties, and a mixture of superior IGER-bred F2 breeding lines

Observations of the Io plasma torus

The short wavelength spectrography on the IUE satellite was used to obtain spectra of the plasma torus near the orbit of Io about Jupiter. Three exposures of about 8 hours each taken in March and May 1979 show emission features due to SII, SIII, and OIII. The absence of features at other wavelengths permits upper limits to be other species in the torus

Parafermionic conformal field theory on the lattice

Finding the precise correspondence between lattice operators and the continuum fields that describe their long-distance properties is a largely open problem for strongly interacting critical points. Here we solve this problem essentially completely in the case of the three-state Potts model, which exhibits a phase transition described by a strongly interacting 'parafermion' conformal field theory. Using symmetry arguments, insights from integrability, and extensive simulations, we construct lattice analogues of nearly all the relevant and marginal physical fields governing this transition. This construction includes chiral fields such as the parafermion. Along the way we also clarify the structure of operator product expansions between order and disorder fields, which we confirm numerically. Our results both suggest a systematic methodology for attacking non-free field theories on the lattice and find broader applications in the pursuit of exotic topologically ordered phases of matter.Comment: 27 pages, 4 figures; v2 added reference

Observations of polar aurora on Jupiter

North-south spatial maps of Jupiter were obtained with the SWP camera in IUE observations of 10 December 1978, 19 May 1979, and 7 June 1979. Bright auroral emissions were detected from the north and south polar regions at H Ly alpha (1216 A) and in the H2 Lyman bands (1250-1608 A) on 19 May 1979; yet no enhanced polar emission was detected on the other days. The relationship between the IUE observing geometry and the geometry of the Jovian magnetosphere is discussed

Vocal communication in gibbons.

Many non-human primates use vocal communication referentially and also use simple syntax and grammar. However, their comparative vocal repertoires are disappointingly sparse, with many researchers concluding that they have fixed vocal patterns made up of a limited number of discrete units used in a relatively small array of contexts (see McComb & Semple, 2005 for a review). Furthermore, these vocal patterns seem to be innate, under high genetic control with little evidence for vocal learning – something that humans are masters at (Janik & Slater 1997). This leaves us with some questions. Firstly, how did humans become so adept at producing and learning vocal sounds? And, secondly, are there any extant primate species with vocal behaviours that can be directly compared to our own?

Tunable backaction of a dc SQUID on an integrated micromechanical resonator

We have measured the backaction of a dc superconducting quantum interference device (SQUID) position detector on an integrated 1 MHz flexural resonator. The frequency and quality factor of the micromechanical resonator can be tuned with bias current and applied magnetic flux. The backaction is caused by the Lorentz force due to the change in circulating current when the resonator displaces. The experimental features are reproduced by numerical calculations using the resistively and capacitively shunted junction (RCSJ) model.Comment: Submitted to Phys. Rev. Let