On the verge of Umdeutung in Minnesota: Van Vleck and the correspondence principle (Part One)

In October 1924, the Physical Review, a relatively minor journal at the time, published a remarkable two-part paper by John H. Van Vleck, working in virtual isolation at the University of Minnesota. Van Vleck combined advanced techniques of classical mechanics with Bohr's correspondence principle and Einstein's quantum theory of radiation to find quantum analogues of classical expressions for the emission, absorption, and dispersion of radiation. For modern readers Van Vleck's paper is much easier to follow than the famous paper by Kramers and Heisenberg on dispersion theory, which covers similar terrain and is widely credited to have led directly to Heisenberg's "Umdeutung" paper. This makes Van Vleck's paper extremely valuable for the reconstruction of the genesis of matrix mechanics. It also makes it tempting to ask why Van Vleck did not take the next step and develop matrix mechanics himself.Comment: 82 page

Moment of Inertia and Quadrupole Response Function of a Trapped Superfluid

We derive an explicit relationship between the moment of inertia and the quadrupole response function of an interacting gas confined in a harmonic trap. The relationship holds for both Bose and Fermi systems and is well suited to reveal the effects of irrotationality of the superfluid motion. Recent experimental results on the scissors mode are used to extract the value of the moment of inertia of a trapped Bose gas and to point out the deviations from the rigid value due to superfluidity.Comment: 6 page

Pig farmers’ willingness to pay for management strategies to reduce aggression between pigs

When deciding whether to invest in an improvement to animal welfare, farmers must trade-off the relative costs and benefits. Despite the existence of effective solutions to many animal welfare issues, farmers’ willingness to pay for them is largely unknown. This study modelled pig farmers’ decisions to improve animal welfare using a discrete choice experiment focused on alleviating aggression between growing/finishing pigs at regrouping. Eighty-two UK and Irish pig farm owners and managers were asked to choose between hypothetical aggression control strategies described in terms of four attributes; installation cost, on-going cost, impact on skin lesions from aggression and impact on growth rate. If they did not like any of the strategies they could opt to keep their current farm practice. Systematic variations in product attributes allowed farmers’ preferences and willingness to pay to be estimated and latent class modelling accounted for heterogeneity in responses. The overall willingness to pay to reduce lesions was low at £0.06 per pig place (installation cost) and £0.01 per pig produced (running cost) for each 1% reduction in lesions. Results revealed three independent classes of farmers. Farmers in Class 1 were unlikely to regroup unfamiliar growing/finishing pigs, and thus were unwilling to adopt measures to reduce aggression at regrouping. Farmers in Classes 2 and 3 were willing to adopt measures providing certain pre-conditions were met. Farmers in Class 2 were motivated mainly by business goals, whilst farmers in Class 3 were motivated by both business and animal welfare goals, and were willing to pay the most to reduce aggression; £0.11 per pig place and £0.03 per pig produced for each 1% reduction in lesions. Farmers should not be considered a homogeneous group regarding the adoption of animal welfare innovations. Instead, campaigns should be targeted at subgroups according to their independent preferences and willingness to pay

Sowing the Wind and Reaping the Whirlwind? The Effect of Wind Turbines on Residential Well-Being

This paper investigates the effect of wind turbines on residential well-being in Germany, using panel data from the German Socio-Economic Panel (SOEP) and a unique, novel data set on wind turbines for the time period between 2000 and 2012. Using a Geographical Information System (GIS), it calculates the distance from households to the nearest wind turbines to determine whether an individual is affected by disamenities, e.g. through visual pollution. The depth of our unique, novel data set on wind turbines, which has been collected at the regional level and which includes, besides their exact geographical coordinates, their construction dates, allows estimating the causal effect of wind turbines on residential well-being, using difference-in-difference propensity-score and spatial matching techniques. We demonstrate that the construction of a new wind turbine in a treatment area of 4000 metres around households has a significantly negative impact on life satisfaction. Moreover, this effect is found to be of transitory nature. Contrasting the implicit monetary valuation with the damage through CO2 emissions avoided by wind turbines, wind power turns out to be a favorable technology despite robust evidence for negative externalities

Developing the Questionnaire

AbstractThis chapter outlines the essential topics for developing and testing a questionnaire for a discrete choice experiment survey. It addresses issues such as the description of the environmental good, pretesting of the survey, incentive compatibility, consequentiality or mitigation of hypothetical bias. For the latter, cheap talk scripts, opt-out reminders or an oath script are discussed. Moreover, the use of instructional choice sets, the identification of protest responses and strategic bidders are considered. Finally, issues related to the payment vehicle and the cost vector design are the subject of this section

Les propriétés optiques de l'eau dans le spectre infra-rouge

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