Correlated random fields in dielectric and spin glasses

Both orientational glasses and dipolar glasses possess an intrinsic random field, coming from the volume difference between impurity and host ions. We show this suppresses the glass transition, causing instead a crossover to the low $T$ phase. Moreover the random field is correlated with the inter-impurity interactions, and has a broad distribution. This leads to a peculiar variant of the Imry-Ma mechanism, with 'domains' of impurities oriented by a few frozen pairs. These domains are small: predictions of domain size are given for specific systems, and their possible experimental verification is outlined. In magnetic glasses in zero field the glass transition survives, because the random fields are disallowed by time-reversal symmetry; applying a magnetic field then generates random fields, and suppresses the spin glass transition.Comment: minor modifications, final versio

Armstrong and Neely-Kinyon Research Farms Summary

Includes Wallace Foundation for Rural Research and Development 2010 President\u27s Report, Farm and Weather Summary, Research Farm Projects and Information on Experiments in Previous Annual Progress Reports

Development of food photographs for use with children aged 18 months to 16 years:comparison against weighed food diaries – The Young Person’s Food Atlas (UK)

Traditional dietary assessment methods, used in the UK, such as weighed food diaries impose a large participant burden, often resulting in difficulty recruiting representative samples and underreporting of energy intakes. One approach to reducing the burden placed on the participant is to use portion size assessment tools to obtain an estimate of the amount of food consumed, removing the need to weigh all foods. An age range specific food atlas was developed for use in assessing children’s dietary intakes. The foods selected and portion sizes depicted were derived from intakes recorded during the UK National Diet and Nutrition Surveys of children aged 1.5 to 16 years. Estimates of food portion sizes using the food atlas were compared against 4-day weighed intakes along with in-school / nursery observations, by the research team. Interviews were conducted with parents the day after completion of the diary, and for children aged 4 to 16 years, also with the child. Mean estimates of portion size consumed were within 7% of the weight of food recorded in the weighed food diary. The limits of agreement were wide indicating high variability of estimates at the individual level but the precision increased with increasing age. For children 11 years and over, agreement with weighed food diaries, was as good as that of their parents in terms of total weight of food consumed and of intake of energy and key nutrients. The age appropriate food photographs offer an alternative to weighed intakes for dietary assessment with children

Decoherence and Quantum Walks: anomalous diffusion and ballistic tails

The common perception is that strong coupling to the environment will always render the evolution of the system density matrix quasi-classical (in fact, diffusive) in the long time limit. We present here a counter-example, in which a particle makes quantum transitions between the sites of a d-dimensional hypercubic lattice whilst strongly coupled to a bath of two-level systems which 'record' the transitions. The long-time evolution of an initial wave packet is found to be most unusual: the mean square displacement of the particle density matrix shows long-range ballitic behaviour, but simultaneously a kind of weakly-localised behaviour near the origin. This result may have important implications for the design of quantum computing algorithms, since it describes a class of quantum walks.Comment: 4 pages, 1 figur

Method of Collective Degrees of Freedom in Spin Coherent State Path Integral

We present a detailed field theoretic description of those collective degrees of freedom (CDF) which are relevant to study macroscopic quantum dynamics of a quasi-one-dimensional ferromagnetic domain wall. We apply spin coherent state path integral (SCSPI) in the proper discrete time formalism (a) to extract the relevant CDF's, namely, the center position and the chirality of the domain wall, which originate from the translation and the rotation invariances of the system in question, and (b) to derive effective action for the CDF's by elimination of environmental zero-modes with the help of the {\it Faddeev-Popov technique}. The resulting effective action turns out to be such that both the center position and the chirality can be formally described by boson coherent state path integral. However, this is only formal; there is a subtle departure from the latter.Comment: 10 pages, 1 figur

Einfluss von lebenden Mulchen auf die Begleitflora und die Weizenerträge unter Bedingungen des Ökolandbau

For the success of no-tillage in organic farming, new tools have to be developed to control weeds. One possible strategy could be sowing the main crop into an earlier established living mulch of easily controllable cover crops. Field trials were carried out in the Swiss midlands to investigate the impact of different legume cover crops on weed populations and grain yield of directly drilled winter wheat (Triticum aestivum L.) in a living mulch system. In general, weed suppressing effect was best with highly productive legumes. A significant reduction of the weed density of dicotyle, monocotyle, and spring germinating species was observed. Though, effective weed suppression resulted also in strong competition with the winter wheat. In order to improve the practicability of such systems, seeding technique of the main crop and living mulch management should be investigated

Rapid attainment of a doubled haploid line from transgenic maize ( Zea mays L.) plants by means of anther culture

Summary: We present a strategy for establishing a transgenic doubled haploid maize line from heterozygous transgenic material by means of anther culture. Compared to conventional inbreeding, the in vitro androgenesis technique enables a faster generation of virtually fully homozygous lines. Since the androgenic response is highly genotype-dependent, we crossed transgenic, non-androgenic plants carrying a herbicide resistance marker gene (pat, encoding for phosphinothricin acetyl transferase) with a highly androgenic genotype. The transgenic progenies were used as donor plants for anther culture. One transgenic and three non-transgenic doubled haploid lines have been established within approximately 1 yr. The homozygosity of all four doubled haploid lines was tested by analysis of simple sequence repeat (SSR) markers at 19 different loci. Polymorphisms were found between the lines but not within the lines indicating the homozygous nature of the entire plant genome gained by anther culture. Southern blot analysis revealed that the transgenic donor plants and their doubled haploid progeny exhibited the same integration pattern of the pat gene. No segregation of the herbicide resistance trait has been observed among the progeny of the transgenic doubled haploid lin

A Case Study of Using Mobile Applications and Peripherals to Encourage “Real-Life” Critical Analysis in Human Physiology

This paper shares a practice of encouraging critical analysis in science students by comparing mobile applications and peripherals to traditional tools to record physiological variables such as heart rate and blood pressure. A progressive series of case studies is described with learning outcomes mapped to the benchmark statement for Bioscience from the United Kingdom's Quality Assurance Agency. A student reflection and staff commentary of the practice is also offered

Chlorophyll fluorescence as a selection tool for cold tolerance of photosynthesis in maize (Zea mays L.)

The possibility of using quenching analysis of chlorophyll a fluorescence as a selection tool for improving the cold tolerance of maize was investigated in six genotypes differing greatly in the ability to develop a competent photosynthetic apparatus at low temperature. Upon gradual cooling, measurements of the quantum yield of electron transport (ΦPSII) indicated that leaves of tolerant genotypes, that developed at suboptimal temperature (15 °C), maintained higher rates of electron transport than leaves of sensitive genotypes. This difference was largely due to the ability of the tolerant plants to keep higher efficiency of excitation energy capture by open photosystem II reaction centres (F′v/F′m). The absence of genotypic differences in leaves that developed at optimal temperature indicates that the trait is not expressed constitutively, but relies on adaptation mechanisms. Furthermore, the genotypic difference was not expressed under increasing illumination at 15 °C and 25 °C suggesting that the trait is also low-temperature-specific and is not expressed solely in response to increasing excess light energy. Applying the method to flint and dent breeding population led to a substantial increase (up to 31%) in the photosynthetic capacity of hybrids between selected F3 inbreeding families grown at suboptimal temperature, demonstrating that the method is an efficient selection tool for improving the cold tolerance of maize through breedin