The theory of incentives applied to the transport sector

Building upon Iossa and Martimort (2008), we study the main incentive issues and the form of optimal contracts for Public Private Partnerships (PPPs) in transports. We present a basic model of procurement in a multitask environment in which a risk-averse firm chooses unobservable efforts in infrastructure and service quality. We begin by analyzing the effect on incentives and risk transfer of bundling building and operation into a single contract. We consider the factors that affect the optimal allocation of demand risk and their implications for the choice of contract length. We discuss the dynamics of PPP contracts and how the risk of regulatory opportunism affects contract design and incentives

The simple micro-economics of public-private partnerships

We build a unified theoretical framework to analyze the main incentive issues in Public Private Partnerships (PPPs) and the shape of optimal contracts in those contexts. We present a basic model of procurement in a multitask environment in which a risk-averse agent chooses unobservable efforts in cost reduction and quality improvement. We begin by studying the effect on incentives and risk transfer of bundling building and operation into a single contract, allowing for different assumptions on the contractual framework and the quality of the information held by the government. We then extend the basic model in several directions. We consider the factors that affect the optimal allocation of demand risk and their implications for the use of user charges and the choice of contract length. We study the relationship between the operator and its financiers and the impact of private finance. We discuss the trade-off between incentive and flexibility in long-term PPP agreements and the dynamics of PPP contracts, including cost overruns. We also consider how the institutional environment, and specifically the risk of regulatory opportunism, affects contract design and incentives. We conclude with some policy implications on the desirability of PPPs

Exact solution of Kerr black hole perturbations via CFT2 and instanton counting: Greybody factor, quasinormal modes, and Love numbers

We give explicit expressions for the finite frequency greybody factor, quasinormal modes, and Love numbers of Kerr black holes by computing the exact connection coefficients of the radial and angular parts of the Teukolsky equation. This is obtained by solving the connection problem of the confluent Heun equation in terms of the explicit expression of irregular Virasoro conformal blocks as sums over partitions via the Alday, Gaiotto, and Tachikawa correspondence. In the relevant approximation limits our results are in agreement with existing literature. The method we use can be extended to solve the linearized Einstein equation in other interesting gravitational backgrounds

Changes in the distribution of red foxes (Vulpes vulpes) in urban areas in Great Britain: findings and limitations of a media-driven nationwide survey

Urbanization is one of the major forms of habitat alteration occurring at the present time. Although this is typically deleterious to biodiversity, some species flourish within these human-modified landscapes, potentially leading to negative and/or positive interactions between people and wildlife. Hence, up-to-date assessment of urban wildlife populations is important for developing appropriate management strategies. Surveying urban wildlife is limited by land partition and private ownership, rendering many common survey techniques difficult. Garnering public involvement is one solution, but this method is constrained by the inherent biases of non-standardised survey effort associated with voluntary participation. We used a television-led media approach to solicit national participation in an online sightings survey to investigate changes in the distribution of urban foxes in Great Britain and to explore relationships between urban features and fox occurrence and sightings density. Our results show that media-based approaches can generate a large national database on the current distribution of a recognisable species. Fox distribution in England and Wales has changed markedly within the last 25 years, with sightings submitted from 91% of urban areas previously predicted to support few or no foxes. Data were highly skewed with 90% of urban areas having <30 fox sightings per 1000 people km-2. The extent of total urban area was the only variable with a significant impact on both fox occurrence and sightings density in urban areas; longitude and percentage of public green urban space were respectively, significantly positively and negatively associated with sightings density only. Latitude, and distance to nearest neighbouring conurbation had no impact on either occurrence or sightings density. Given the limitations associated with this method, further investigations are needed to determine the association between sightings density and actual fox density, and variability of fox density within and between urban areas in Britain

The evolution of acoustic size exaggeration in terrestrial mammals

Recent studies have revealed that some mammals possess adaptations that enable them to produce vocal signals with much lower fundamental frequency (F0) and formant frequency spacing (ΔF) than expected for their size. Although these adaptations are assumed to reflect selection pressures for males to lower frequency components and exaggerate body size in reproductive contexts, this hypothesis has not been tested across a broad range of species. Here we show that male terrestrial mammals produce vocal signals with lower ΔF (but not F0) than expected for their size in mating systems with greater sexual size dimorphism. We also reveal that males produce calls with higher than expected F0 and ΔF in species with increased sperm competition. This investigation confirms that sexual selection favours the use of ΔF as an acoustic size exaggerator, and supports the notion of an evolutionary trade-off between pre-copulatory signalling displays and sperm production

International Mammal Trapping Standards ̶- Part I: Prerequisites

In this paper, we set out the prerequisites for the development of killing and restraining trap systems to capture mammals for research, wildlife management and conservation, fur trapping, animal control, and any other activity involving the trapping of a mammal in a mechanical trapping device. We selected them with the main intent of developing new trapping standards that will improve animal welfare as per our current state of knowledge, and with realistic, achievable objectives based on state-of-the-art trapping technology. The proposed new standards should be applicable to all terrestrial and semi-aquatic mammal species. They should be based on animal testing in semi-natural environments and on traplines, with high trap thresholds of acceptance, low times to irreversible unconsciousness for killing trap systems, an understanding of the impacts of trapping on physical form, behaviour and physiological function, adequate trap checking times and handling of the captured animals, and high capture selectivity. Furthermore, the implementation of improved trapping standards would include the mandatory publication of findings for peer-review and public education. We believe that the prerequisites that we lay out for the development of new mammal trapping standards will address many of the welfare concerns voiced by the scientific community and the public in the last two decades. It will lead to improved animal welfare and spur continuous improvement in the efficacy and innovation in trapping technology

International mammal trapping standards, Part III: Restraining trap systems

In this paper, we propose standards for restraining trap systems based on Proulx et al.’s (2022a) prerequisites, which provide context and explanations for our approach. Our aim is to identify assessment protocols that are based on the scientific method, and that include evaluation parameters and threshold levels of acceptation, and laboratory and field procedures, to recognize mammal trapping systems that are acceptable from an animal welfare, and capture efficiency and selectivity, point of view. The testing of restraining trap systems consists of 3 steps: 1) Mechanical evaluation for leghold trapping devices; 2) Restraining tests in semi-natural environments; and 3) Restraining tests on traplines. On the basis of the normal approximation to the binomial distribution, a restraining trap system is acceptable if, at a 95% confidence level, it holds ≥85% of the animals without serious injuries (<50 points), signs of distress or exertion during ≥50% of captivity time, and without significant elevated stress, exertion or dehydration for the duration of the captivity period. We recommend that these standards be implemented and continuously updated as new designs and technology is developed