Airport incentive programs: A European perspective

In this paper we investigate current pricing practices at the 200 biggest airports in the European Union. Our analysis shows that airport incentive programs are, in general, a common tool of airport pricing as they are used at one third of all airports. We also find evidence on the presence of bilateral agreements between airport operators or regional authorities on one side and airlines on the other side which serve as a substitute for published incentive programs. Geographically, usage of the different tools varies substantially between different EU countries. A detailed assessment of the incentive schemes offered at German airports within our broader European sample reveals that the average level of landing and take-off, parking and positioning and passenger charges is generally reduced by more than 10%, at smaller airports even by up to 44%. Given the usually low profit margin of airlines and that airport charges account for up to 10% of total operating costs, these incentives can have an important influence on the economic viability of a route. Moreover, in an airline's multi-criteria-based assessment of potential market entries or route expansions, such incentive schemes might compensate selected weaknesses of an airport's strategic posture

A Rapid, Physiologic Protocol for Testing Transcriptional Effects of Thyroid-Disrupting Agents in Premetamorphic Xenopus Tadpoles

Increasing numbers of substances present in the environment are postulated to have endocrine-disrupting effects on vertebrate populations. However, data on disruption of thyroid signaling are fragmentary, particularly at the molecular level. Thyroid hormone (TH; triiodothyronine, T(3)) acts principally by modulating transcription from target genes; thus, thyroid signaling is particularly amenable to analysis with a transcriptional assay. Also, T(3) orchestrates amphibian metamorphosis, thereby providing an exceptional model for identifying thyroid-disrupting chemicals. We combined these two advantages to develop a method for following and quantifying the transcriptional action of T(3) in Xenopus laevis tadpoles. This technology provides a means of assessing thyroid activity at the molecular level in a physiologically relevant situation. Moreover, translucent tadpoles are amenable to “on-line” imaging with fluorescent reporter constructs that facilitate in vivo measurement of transcriptional activity. We adapted transgenesis with TH-responsive elements coupled to either luciferase or green fluorescent protein to follow T(3)-dependent transcription in vivo. To reduce time of exposure and to synchronize responses, we optimized a physiologic pre-treatment protocol that induced competence to respond to T(3) and thus to assess T(3) effects and T(3) disruption within 48 hr. This pretreatment protocol was based on a short (24 hr), weak (10(−12) M) pulse of T(3) that induced TH receptors, facilitating and synchronizing the transcriptional responses. This protocol was successfully applied to somatic and germinal transgenesis with both reporter systems. Finally, we show that the transcriptional assay allows detection of the thyroid-disrupting activity of environmentally relevant concentrations (10(−8) M) of acetochlor, a persistent herbicide

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements