Did pterosaurs feed by skimming? Physical modelling and anatomical evaluation of an unusual feeding method

Similarities between the anatomies of living organisms are often used to draw conclusions regarding the ecology and behaviour of extinct animals. Several pterosaur taxa are postulated to have been skim-feeders based largely on supposed convergences of their jaw anatomy with that of the modern skimming bird, Rynchops spp. Using physical and mathematical models of Rynchops bills and pterosaur jaws, we show that skimming is considerably more energetically costly than previously thought for Rynchops and that pterosaurs weighing more than one kilogram would not have been able to skim at all. Furthermore, anatomical comparisons between the highly specialised skull of Rynchops and those of postulated skimming pterosaurs suggest that even smaller forms were poorly adapted for skim-feeding. Our results refute the hypothesis that some pterosaurs commonly used skimming as a foraging method and illustrate the pitfalls involved in extrapolating from limited morphological convergence.

Did pterosaurs feed by skimming? Physical modelling and anatomical evaluation of an unusual feeding method

Similarities between the anatomies of living organisms are often used to draw conclusions regarding the ecology and behaviour of extinct animals. Several pterosaur taxa are postulated to have been skim-feeders based largely on supposed convergences of their jaw anatomy with that of the modern skimming bird, Rynchops spp. Using physical and mathematical models of Rynchops bills and pterosaur jaws, we show that skimming is considerably more energetically costly than previously thought for Rynchops and that pterosaurs weighing more than one kilogram would not have been able to skim at all. Furthermore, anatomical comparisons between the highly specialised skull of Rynchops and those of postulated skimming pterosaurs suggest that even smaller forms were poorly adapted for skim-feeding. Our results refute the hypothesis that some pterosaurs commonly used skimming as a foraging method and illustrate the pitfalls involved in extrapolating from limited morphological convergence.

The impact of real estate on the mixed-asset portfolio in periods of financial stress

The case for holding real estate in the mixed-asset portfolio is typically made on its stabilising effect as a result of its diversification benefits. However, portfolio diversification often fails when it is most needed, i.e. during periods of financial stress. In these periods, the variability of returns for most asset classes increases thus reducing the stabilising effect of a diversified portfolio. This paper applies the approach of Chow et al (1999) to the US domestic mixed-asset portfolio to establish whether real estate, represented by REITs, is especially useful in times of financial stress. To this end monthly returns data on five assets classes: large cap stocks, small cap stocks, long dated government bonds, cash (T-Bills) and real estate (REITs) are evaluated over the period January 1972 to December 2001. The results indicate that the inclusion of REITs in the mixed-asset portfolio can lead to increases or decreases in returns depending on the asset class replaced and whether the period is one of calm or stress. However, the inclusion of REITs invariably leads to reductions in portfolio risk that are greater than any loss in return, especially in periods of financial stress. In other words, REITs acts as a stabilising force on the mixed-asset portfolio when it is most needed, i.e. in periods of financial stress.

Making the least active pay: a simulation of rewards and penalties under Demand Side Participation programs

The orthodox approach for incentivising Demand Side Participation (DSP) programs is that utility losses from capital, installation and planning costs should be recovered under financial incentive mechanisms which aim to ensure that utilities have the right incentives to implement DSP activities. The recent national smart metering roll-out in the UK implies that this approach needs to be reassessed since utilities will recover the capital costs associated with DSP technology through bills. This paper introduces a reward and penalty mechanism focusing on residential users. DSP planning costs are recovered through payments from those consumers who do not react to peak signals. Those consumers who do react are rewarded by paying lower bills. Because real-time incentives to residential consumers tend to fail due to the negligible amounts associated with net gains (and losses) or individual users, in the proposed mechanism the regulator determines benchmarks which are matched against responses to signals and caps the level of rewards/penalties to avoid market distortions. The paper presents an overview of existing financial incentive mechanisms for DSP; introduces the reward/penalty mechanism aimed at fostering DSP under the hypothesis of smart metering roll-out; considers the costs faced by utilities for DSP programs; assesses linear rate effects and value changes; introduces compensatory weights for those consumers who have physical or financial impediments; and shows findings based on simulation runs on three discrete levels of elasticity.

Modelling the implied volatility of options on long gilt futures

This paper investigates the properties of implied volatility series calculated from options on Treasury bond futures, traded on LIFFE. We demonstrate that the use of near-maturity at the money options to calculate implied volatilities causes less mis-pricing and is therefore superior to, a weighted average measure encompassing all relevant options. We demonstrate that, whilst a set of macroeconomic variables has some predictive power for implied volatilities, we are not able to earn excess returns by trading on the basis of these predictions once we allow for typical investor transactions costs.

Revenue-neutral tax policy under price uncertainty

The firm's response to revenue-neutral taxation is investigated under price uncertainty. Revenue-neutral policies adjust simultaneously the marginal tax rate and the level of exemptions while keeping expected tax receipts constant. Nonincreasing absolute risk aversion is sufficient to sign the firm's response: a reduction in the marginal rate causes the firm to contract output. Implications are established for the equilibrium level of treasury receipts.

Donationes mortis causa in a dematerialised world

Subject: Real property. Other related subjects: Personal property. Trusts Keywords: Bank accounts; Documents of title; Donatio mortis causa; Electronic documents; Legal charges; Registered land; Shares Legislation: Land Registration Act 2002 (c.9) Cases: Sen v Headley [1991] Ch. 425; Guardian, April 23, 1991 (CA (Civ Div)); Duffield v Elwes 4 E.R. 959 (KB); Birch v Treasury Solicitor [1951] Ch. 298 (CA)

'Score it upon my taille': the use (and abuse) of tallies by the medieval Exchequer

The paper traces the evolution of the tally from a receipt for cash payments into the treasury, to proof of payments made by royal officials outside of the treasury and finally to an assignment of revenue to be paid out by royal officials. Each of these processes is illustrated by examples drawn from the Exchequer records and explains their significance for royal finance and for historians working on the Exchequer records.

The cyclical relations between traded property stock prices and aggregate time-series

This paper examines the cyclical regularities of macroeconomic, financial and property market aggregates in relation to the property stock price cycle in the UK. The Hodrick Prescott filter is employed to fit a long-term trend to the raw data, and to derive the short-term cycles of each series. It is found that the cycles of consumer expenditure, total consumption per capita, the dividend yield and the long-term bond yield are moderately correlated, and mainly coincident, with the property price cycle. There is also evidence that the nominal and real Treasury Bill rates and the interest rate spread lead this cycle by one or two quarters, and therefore that these series can be considered leading indicators of property stock prices. This study recommends that macroeconomic and financial variables can provide useful information to explain and potentially to forecast movements of property-backed stock returns in the UK.

Identifying trends in domestic electricity consumption in Botswana

Data on electricity consumption patterns relating to different end uses in domestic houses in Botswana is virtually non-existent, despite the fact that the total electricity consumption patterns are available. This can be attributed to the lack of measured and quantified data and in other instances the lack of modern technology to perform such investigations. This paper presents findings from initial studies that are envisaged to bridge the gap. Electricity consumption patterns of 73 domestic households across three cities have been studied. This was carried out through a questionnaire survey, calculated national metering data and electricity measurements. All together nine appliance groups were identified. The results showed the mean electricity consumption for the households considering the calculated consumption from bills and the survey to be t = 4.23; p < 0.000067, two-tailed. The findings of this paper focus on a relatively small sample size (73). It would therefore not be wise to draw sweeping conclusions from the analysis or to make statements that would be aimed at influencing policies. However, the results presented forms a formidable base for further research, which is currently on going.

Profits, malversations, restitutions. Les bénéfices des financiers durant la guerre de la Ligue d’Augsbourg et la taxe de Chamillart

Profit, embezzlement, restitution. The role of the traitants in the Nine Years War and Chamillart’s tax on financial benefits The aim of this article is to revisit the question of the financiers in Old Regime France. It starts with an analysis of the discourses about the financiers under the Absolute monarchy that underlines the complexity of their relationship with the government and the public. It then reviews the secondary literature and highlights the existence of competing historical interpretations (functional, political, utilitarian), which raise the question of their overall capacity to account for the role and impact of the financiers at different times. On this ground, the article focuses on a specific group of financiers, the so-called traitants d’affaires extraordinaires, during the Nine Years War. Further to a description of the specific role and scope of the activities of the various financiers responsible for helping the monarchy to raise the funds it needed to pay for its peace and wartime expenditure, the article examines the conditions and profits granted by the king in his contracts with the traitants whose services were hired for the purpose of selling royal offices in the public and advancing the revenue to the Treasury. It also explores the contractual arrangements of the companies established by the financiers to manage their operations as well as the rights and the responsibilities of their various stakeholders. These bases being laid, the article relies on the administrative correspondence relating to the traités during the Nine Years War to address a range of issues, in particular the extent to which these contracts, and other control procedures, were robust enough to deter fraud. The accounts of two traitants’ companies offer an opportunity to analyse and compare the structure of their income and expenditure (including the volume and cost of the promissory notes sold in the public to finance their payments to the Treasury), to explore the strategies of the contractors, to calculate their net profits and further discuss the problem of embezzlement. The article ends with the study of the context and debates which led to the introduction by finance minister Michel Chamillart, in 1700, of a shortfall tax on the financial profits of the gens d’affaires or traitants, the method used to determine its rate (50 % of the net benefits), its distribution among the various stakeholders (including the bailleurs de fonds or backers), and the related procedures. In total, the article argues that the relationship between the monarchy, society and the financiers under the Ancien Regime was not static and, therefore, suggests that the broad question of control and fraud must be examined against changing circumstances. With regard specifically to the Nine Years War, the article concludes that within the constraints of the Absolute monarchy, contractors offered valuable services by raising capital for the benefit of a king who ruled over a country which, at the time, was by far the wealthiest in Europe, and where ministers failed to foresee long wars of attrition and whose financial strategy was limited by the very existence of privilege. Overall, the traités were too costly to be a viable system of war financing. In these conditions, the substantial fortunes made by a handful of very successful traitants suffice to explain that the government easily gave in to public criticism against the wealth of the financiers and felt compelled, when peace resumed, to cancel the advantageous conditions offered in the treaties by taxing financial profits.