The Effect of Climatic Variations on Agricultural Risk

The thesis of this paper is that impacts from climatic change can be evaluated effectively as changes in the frequency of short-term, anomalous climatic events. These can then be expressed as changes in the level of risk of impact from climatic extremes. To evaluate this approach, the risk of crop failure resulting from low levels of accumulated temperature is assessed for oats farming in southern Scotland. Annual accumulated temperatures are calculated for the 323-year long temperature record compiled by Manley for Central England. These are bridged across to southern Scotland and, by calculating mean levels of risk for different elevations, an average "risk surface" is constructed. 1-in-10 and 1-in-50 frequencies of crop failure are assumed to delineate a high-risk zone, which is mapped for the 323-year period by constructing isopleths of these risk levels. By re-drawing the risk isopleths for warm and cool 50-year periods, the geographical shift of the high-risk zone is delineated. The conclusion is that relatively recent and apparently minor climatic variations in the United Kingdom have in fact induced substantial spatial changes in levels of agricultural risk. An advantage of expressing climatic change as a change in agricultural risk, is that support programs for agriculture can be re-tuned to accommodate acceptable frequencies of impact by adjusting support levels to match new risk levels

Assessing the Impact of Climatic Change in Cold Regions

In September 1983 IIASA, together with the Austrian Government, the World Resources Institute and UNESCO, supported an International Study Conference on the Sensitivity of Ecosystems and Society to Climatic Change, which was cosponsored by the World Meteorological Organization, UNEP, and the International Council of Scientific Unions. The purpose of this meeting, which was attended by scientists from 17 countries, was to evaluate the impact of climatic fluctuations on the sensitive margins of agriculture and of natural terrestrial ecosystems. The emphasis was on climatic change that might result from increases in the amount of carbon dioxide in the atmosphere, but consideration was also given to past climatic fluctuations, both short- and long-term. This report is a summary of deliberations by participants in the workshop, of the observations that emerged, and of the recommendations made

Assessing Impacts of Climatic Change in Marginal Areas: The Search for an Appropriate Methodology

With the support of the UN Environmental Programme a major 2-year project is currently being initiated to investigate the impacts of short-term climatic variations and the likely long-term effects of CO2-induced climatic changes on agricultural output at the sensitive margins of food grains and livestock production. This paper sets the stage for the above-mentioned project. It reviews the notion of climate-related marginality, and proposes to measure the impact of climatic fluctuations on marginal areas by a temporal change in the level of risk of harvest failure and spatial shifts of crop pay-off boundaries. The practical usefulness of these measures is illustrated by several case examples from the US, Canada, and Northern Europe. Finally, the paper outlines the crop/climate simulation model, successfully applied for analysis of the effects of possible climatic changes on cereal yields in Northern England. Over the next two years it will be the aim of the IIASA project to further develop this methodology and to evaluate the impact on food production of possible changes in climate

Hawking Radiation as Tunneling for Extremal and Rotating Black Holes

The issue concerning semi-classical methods recently developed in deriving the conditions for Hawking radiation as tunneling, is revisited and applied also to rotating black hole solutions as well as to the extremal cases. It is noticed how the tunneling method fixes the temperature of extremal black hole to be zero, unlike the Euclidean regularity method that allows an arbitrary compactification period. A comparison with other approaches is presented.Comment: 17 pages, Latex document, typos corrected, four more references, improved discussion in section

The structure of blocks with a Klein four defect group

We prove Erdmann’s conjecture [16] stating that every block with a Klein four defect group has a simple module with trivial source, and deduce from this that Puig’s finiteness conjecture holds for source algebras of blocks with a Klein four defect group. The proof uses the classification of finite simple groups

Hall effect in the marginal Fermi liquid regime of high-Tc superconductors

The detailed derivation of a theory for transport in quasi-two-dimensional metals, with small-angle elastic scattering and angle-independent inelastic scattering is presented. The transport equation is solved for a model Fermi surface representing a typical cuprate superconductor. Using the small-angle elastic and the inelastic scattering rates deduced from angle-resolved photoemission experiments, good quantitative agreement with the observed anomalous temperature dependence of the Hall angle in optimally doped cuprates is obtained, while the resistivity remains linear in temperature. The theory is also extended to the frequency-dependent complex Hall angle

A modeling framework for assessing adaptation options of Finnish agriculture to climate variability and change

To enable ex ante assessment of alternative adaptation strategies for Finnish agriculture at multiple scales, MTT Agrifood Research Finland and partner institutes recently launched a project Integrated Modeling of Agrifood Systems (IMAGES).The project aims at developing and evaluating different component (economic and biophysical) models and link them in an integrated modeling framework

Measurement of the Strong Coupling alpha s from Four-Jet Observables in e+e- Annihilation

Data from e+e- annihilation into hadrons at centre-of-mass energies between 91 GeV and 209 GeV collected with the OPAL detector at LEP, are used to study the four-jet rate as a function of the Durham algorithm resolution parameter ycut. The four-jet rate is compared to next-to-leading order calculations that include the resummation of large logarithms. The strong coupling measured from the four-jet rate is alphas(Mz0)= 0.1182+-0.0003(stat.)+-0.0015(exp.)+-0.0011(had.)+-0.0012(scale)+-0.0013(mass) in agreement with the world average. Next-to-leading order fits to the D-parameter and thrust minor event-shape observables are also performed for the first time. We find consistent results, but with significantly larger theoretical uncertainties.Comment: 25 pages, 15 figures, Submitted to Euro. Phys. J.

Search for R-Parity Violating Decays of Scalar Fermions at LEP

A search for pair-produced scalar fermions under the assumption that R-parity is not conserved has been performed using data collected with the OPAL detector at LEP. The data samples analysed correspond to an integrated luminosity of about 610 pb-1 collected at centre-of-mass energies of sqrt(s) 189-209 GeV. An important consequence of R-parity violation is that the lightest supersymmetric particle is expected to be unstable. Searches of R-parity violating decays of charged sleptons, sneutrinos and squarks have been performed under the assumptions that the lightest supersymmetric particle decays promptly and that only one of the R-parity violating couplings is dominant for each of the decay modes considered. Such processes would yield final states consisting of leptons, jets, or both with or without missing energy. No significant single-like excess of events has been observed with respect to the Standard Model expectations. Limits on the production cross- section of scalar fermions in R-parity violating scenarios are obtained. Constraints on the supersymmetric particle masses are also presented in an R-parity violating framework analogous to the Constrained Minimal Supersymmetric Standard Model.Comment: 51 pages, 24 figures, Submitted to Eur. Phys. J.