Simple Calculation of Instanton Corrections in Massive N=2 SU(3) SYM

We give an explicit derivation of the Picard-Fuchs equations for N=2 supersymmetric SU(3) Yang-Mills theory with $N_f<6$ massive hypermultiplets in the fundamental representation. We determine the instanton corrections to the prepotential in the weak coupling region using the relation between \tr and the prepotential. This method can be generalized to other gauge groups.Comment: 16 pages, Late

"Blueprint" for the UP Modelling System for Large Scale Hydrology

International audienceThere are at least two needs to be met by the current research efforts on large scale hydrological modelling. The first is for practical conceptual land-surface hydrology schemes for use with existing operational climate and weather forecasting models, to replace the overly simple schemes often used in such models. The second is for models of large scale hydrology which are properly sensitive to changes in physical properties and inputs measured (or predicted) over a wide range of scales, from the point-scale upwards, yet are simple enough in structure to be coupled to climate and weather forecasting models. Such models of large scale hydrology are needed for studying the environmental impact of pollution and changes in climate and land-use, especially the impact On water resources. The UP system (name derived from Upsealed Physically-based) is an attempt to satisfy the second need. It uses a physically-based approach and has a simple structure, yet incorporates sufficient information on sub-grid behaviour to make it a useful tool for the study of environmental impacts over a wide range of scales. The system uses a new approach to large scale modelling, giving physically-based predictions of hourly flows, storages, saturated areas, etc., for regions covering hundreds of thousands of square kilometres. The basic component of the system is the UP element. This has seven water storage compartments (one each for the snowpack, vegetation canopy, surface water, root zone, unsaturated percolation, interflow and groundwater) and allows all the main processes of the terrestrial phase of the hydrological cycle to be represented. A region is modelled as a collection of UP elements, linked by a river routing scheme. Each compartment represents a fixed zone within the area covered by the UP element, and each is related to a physical process such as groundwater flow. Most of the parameterizations for the compartments are in the form of look-up tables, linking the outputs from the compartments to state variables such as the current storage in the compartment. These parameterizations are, in the main, derived from results from physically-based, distributed models applied to the zones (e.g. a groundwater compartment is parameterized using a groundwater model). For large regions modelled using many UP elements, the UP parameters are regionalized using a classification scheme, thus reducing the overall effort spent in parameterization. The development of the UP system is a long-term project involving research into physically-based parameterization of large scale hydrology models, including the effects of sub-grid spatial variations. The first stage involved developing a "blueprint" for the UP element, based on experience with physically-based, distributed river basin modelling and reviews of existing techniques and modelling approaches for large scale and linked atmosphere-hydrology modelling. This paper describes the UP element and the concepts and ideas behind the development of the UP system and, briefly, describes some of the research and development work currently in progress on UP and its parameterization

Hazard Contribution Modes of Machine Learning Components

Amongst the essential steps to be taken towards developing and deploying safe systems with embedded learning-enabled components (LECs) i.e., software components that use ma- chine learning (ML)are to analyze and understand the con- tribution of the constituent LECs to safety, and to assure that those contributions have been appropriately managed. This paper addresses both steps by, first, introducing the notion of hazard contribution modes (HCMs) a categorization of the ways in which the ML elements of LECs can contribute to hazardous system states; and, second, describing how argumentation patterns can capture the reasoning that can be used to assure HCM mitigation. Our framework is generic in the sense that the categories of HCMs developed i) can admit different learning schemes, i.e., supervised, unsupervised, and reinforcement learning, and ii) are not dependent on the type of system in which the LECs are embedded, i.e., both cyber and cyber-physical systems. One of the goals of this work is to serve a starting point for systematizing L analysis towards eventually automating it in a tool

Toxic Hazards Research Unit annual technical report, 1969 Final report, Jun. 1968 - May 1969

Apollo materials toxicity screening tests and effects of ethylene glycol, monomethylhydrazine, NF3, OF2, and ClF

A Case of Fibroma of the Ovary.*

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Improving supplementary feeding in species conservation

Supplementary feeding is often a knee-jerk reaction to population declines, and its application is not critically evaluated, leading to polarized views among managers on its usefulness. Here, we advocate a more strategic approach to supplementary feeding so that the choice to use it is clearly justified over, or in combination with, other management actions and the predicted consequences are then critically assessed following implementation. We propose combining methods from a set of specialist disciplines that will allow critical evaluation of the need, benefit, and risks of food supplementation. Through the use of nutritional ecology, population ecology, and structured decision making, conservation managers can make better choices about what and how to feed by estimating consequences on population recovery across a range of possible actions. This structured approach also informs targeted monitoring and more clearly allows supplementary feeding to be integrated in recovery plans and reduces the risk of inefficient decisions. In New Zealand, managers of the endangered Hihi (Notiomystis cincta) often rely on supplementary feeding to support reintroduced populations. On Kapiti island the reintroduced Hihi population has responded well to food supplementation, but the logistics of providing an increasing demand recently outstretched management capacity. To decide whether and how the feeding regime should be revised, managers used a structured decision making approach informed by population responses to alternative feeding regimes. The decision was made to reduce the spatial distribution of feeders and invest saved time in increasing volume of food delivered into a smaller core area. The approach used allowed a transparent and defendable management decision in regard to supplementary feeding, reflecting the multiple objectives of managers and their priorities

Body size changes in passerine birds introduced to New Zealand from the UK

One feature of global geographic variation in avian body sizes is that they are larger on isolated islands than on continental regions. Therefore, this study aims to assess whether there have been changes in body size following successful establishment for seven passerine bird species (blackbird Turdus merula, song thrush T. philomelos, house sparrow Passer domesticus, chaffinch Fringilla coelebs, greenfinch Chloris chloris, goldfinch Carduelis carduelis, yellowhammer Emberiza citrinella) introduced from the continental islands of the UK to the more isolated oceanic landmass of New Zealand in the middle of the nineteenth century. Measures of tarsus length were taken from individuals from contemporary UK and New Zealand populations of these species, and from historical specimens collected around the time that individuals were translocated from the UK to New Zealand. Analysis of Variance was used to test for size differences between contemporary UK and New Zealand populations, and between historical UK and contemporary UK and New Zealand populations. Historical UK populations have longer tarsi, on average, than 12 (7 UK and 5 New Zealand) of the 14 contemporary populations. Significant decreases in tarsus length relative to the historical populations have occurred in the UK for blackbird, chaffinch and greenfinch, and in the New Zealand blackbird population. Contemporary New Zealand house sparrows have significantly longer tarsi, on average, than both historical and contemporary UK populations. Exposure to novel environments may be expected to lead to changes in the morphology and other traits of exotic species, but changes have also occurred in the native range. In fact, contrary to expectations, the most common differences we found were between contemporary and historical UK populations. Consideration of contemporary populations alone would underestimate the true scale of morphological change in these species over time, which may be due to phenotypic plasticity or genetic adaptation to environmental changes experienced by all populations in the last 150 years

Characterization of vertical electric fields and associated voltages induced on a overhead power line from close artificially initiated lightning

Measurements were characterized of simultaneous vertical electric fields and voltages induced at both ends of a 448 m overhead power line by artificially initiated lightning return strokes. The lightning discharges struck ground about 20 m from one end of the line. The measured line voltages could be grouped into two categories: those in which multiple, similarly shaped, evenly spaced pulses were observed, which are called oscillatory; and those dominated by a principal pulse with subsidiary oscillations of much smaller amplitude, which are called impulsive. Voltage amplitudes range from tens of kilovolts for oscillatory voltages to hundreds of kilovolts for impulsive voltages

Substituent effects on the mechanochemical response of zinc dialkyldithiophosphate

Mechanochemistry is known to play a key role in the function of some lubricant additives, such as the tribofilm growth of zinc dialkyldithiophosphate (ZDDP). This raises the intriguing possibility of tailoring the mechanochemical response of additives by modifying their alkyl substituents. Here, we study the tribofilm formation rate of ZDDPs containing several different alkyl groups on steel surfaces from a high-friction base oil. We use macroscale tribometer experiments under full-film elastohydrodynamic lubrication conditions to enable careful control of the temperature and stress during tribofilm growth. We show how the chain length and the presence of branches or bulky cycloaliphatic groups can lead to large differences in the temperature- and stress-dependencies of the tribofilm formation rate, which can be explained through variations in packing density, steric hindrance, and stress transmission efficiency. Our rate data are successfully fitted using the Bell model; a simple modification of the Arrhenius equation that is commonly employed to model the kinetics of mechanochemical processes. Using this model, we observe large differences in the activation energy, pre-exponential factor, and activation volume for the various ZDDPs. Our findings show how structure–performance relationships can be identified for lubricant additives, which may be useful to optimise their molecular structure