Adrian C. Newton

Bio: Adrian C. Newton is an academic researcher from James Hutton Institute. The author has contributed to research in topics: Hordeum vulgare & Biodiversity. The author has an hindex of 74, co-authored 453 publications receiving 21814 citations. Previous affiliations of Adrian C. Newton include Seattle Children's Research Institute & University of Peradeniya.

Temporary partial breakdown of Mlo‐resistance in spring barley by the sudden relief of soil water stress

Abstract: Seedlings of spring barley cultivars expressing mlo genes for resistance to mildew (Erysiphe graminis f.sp. hordei) in different genetic backgrounds were subjected to degrees of water stress under different nutrient and soil conditions. The temporary breakdown in the host of the expression of Mlo-resistance, reported occasionally under field conditions, was successfully simulated when stress treatments were relieved. Differences in the degree of temporary breakdown where attributable to nutrient status. soil compaction and genetic background of the mlo gene.

Modelling the spread of fungal diseases using a nearest neighbour approach: effect of geometrical arrangement

Abstract: A discrete model of the nearest neighbour type is used to model the growth and spread of fungal disease in a two-cultivar mixture assuming an unspecialized pathogen. Disease dynamics and dispersal are represented by a spatial, single pathotype version of Gumpert's (1992) model that simulated the temporal evolution of a number of pathotypes on a cultivar mixture. Spore dispersal occurs by discrete rules between a cell and its four orthogonal neighbours in a rectangular grid. Parameters termed transmission efficiency rates control the extent of successful inoculum exchange between two neighbouring cells depending on the cultivars present. Spatially averaged disease progress curves are computed for regular block and strip patterns in addition to the mean curve for twenty 1:1 random mixture patterns. These sets of curves are exhibited relative to the appropriate pure stand comparison for a range of auto- and cross-deposition parameters. We conducted simulations for uniform initial infection and also averaged over 20 random initial infection patterns at a comparable mean level. In the former case, provided the ratio of cross-deposition to auto-deposition is high enough and the disease progress curves take sufficiently long to reach their saturation value, the ranking of the geometrical patterns can eventually be interpreted once initial oscillations have subsided. The geometry with the largest proportion of links between neighbouring cells of different cultivar type generally corresponds to the lowest average disease level, but not for averaged simulations based on random initial infection patterns.

Characterization of microclimate in mist and non-mist propagation systems

Abstract: The microclimates of two contrasting propagation systems, a polyethylene-covered mist unit and a low-technology, non-mist polyethylene propagator, were examined in detail over a two year period. Both systems were able to maintain relative humidities (r.h.) of over 90% for much of the time; r.h. below 60% was associated with peaks in irradiance of over 1000 nmol m'2 s'1. Leaf-to-air vapour pressure difference (VPD) tended to vary in a manner similar to irradiance, remaining close to zero during night, and often reaching values over 3.0 kPa during early afternoon. Maximum VPD in the non-mist system was associated with opening of the propagator lid, which caused an immediate decline in r.h. When the propagator lid was kept closed, VPD under mist was consistently 2-3 times higher than under non-mist. The relationship between VPD and irradiance was found to vary both diurnally and from week to week. In general, a large part of the variation in VPD was unaccounted for by irradiance, as air temperature in both s...

The Theory of Island Biogeography

Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

Ecosystems and human well-being: a framework for assessment

Abstract: This first report of the Millennium Ecosystem Assessment describes the conceptual framework that is being used in the MA. It is not a formal assessment of the literature, but rather a scientifically informed presentation of the choices made by the assessment team in structuring the analysis and framing the issues. The conceptual framework elaborated in this report describes the approach and assumptions that will underlie the analysis conducted in the Millennium Ecosystem Assessment. The framework was developed through interactions among the experts involved in the MA as well as stakeholders who will use its findings. It represents one means of examining the linkages between ecosystems and human well-being that is both scientifically credible and relevant to decision-makers. This framework for analysis and decision-making should be of use to a wide array of individuals and institutions in government, the private sector, and civil society that seek to incorporate considerations of ecosystem services in their assessments, plans, and actions.