Non-renewable resource prices: Structural breaks and long term trends

In this paper we examine the time series properties of nine non-renewable resources. In particular we are concerned with understanding the relationship between the number of structural breaks in the data and the nature of the resource price path, i.e. is it stationary or a random walk. To undertake our analysis we employ a number of relevant econometric methods including Bai and Perron`s (1998) multiple structural break dating method. Our results indicate that these series are in many cases stationary and subject to a number of structural breaks. These results indicate that a deterministic model of resources prices may well be appropriate.structural change, non-renewable resources, breaks, resource depletion

Wrapped in the Flag: Food Choice and Country of Origin Labelling

The growth in country of origin (COO) food labelling is part of the ongoing proliferation of information provided to consumers. However, the implementation of COO labelling means that consumers can sometimes end up more confused than informed. This concern raises questions regarding how COO information should be provided, along with what information needs to be given to consumers. We begin by discussing what COO actually indicates. This is followed by a review of the evidence on consumer use of COO information. Then turning to current policy issues, we draw attention to how COO information can be used to promote consumer ethnocentrism as well as inadvertently causing trade tensions both between trading countries and within the EU single market. We then consider how developments in information technology like blockchains or smart labels might change how COO information is collated and used. In particular, we observe that any increase in the use of this technology will depend on whether or not consumers trust these new digital sources of information. Potentially, the convenience with which COO information could be verified by consumers using information technology is a logical development given consumer demands for convenience in general

Distinct modes of floor plate induction in the chick embryo

To begin to reconcile models of floor plate formation in the vertebrate neural tube, we have performed experiments aimed at understanding the development of the early floor plate in the chick embryo. Using real-time analyses of cell behaviour, we provide evidence that the principal contributor to the early neural midline, the future anterior floor plate, exists as a separate population of floor plate precursor cells in the epiblast of the gastrula stage embryo, and does not share a lineage with axial mesoderm. Analysis of the tissue interactions associated with differentiation of these cells to a floor plate fate reveals a role for the nascent prechordal mesoderm, indicating that more than one inductive event is associated with floor plate formation along the length of the neuraxis. We show that Nr1, a chick nodal homologue, is expressed in the nascent prechordal mesoderm and we provide evidence that Nodal signalling can cooperate with Shh to induce the epiblast precursors to a floor-plate fate. These results indicate that a shared lineage with axial mesoderm cells is not a pre-requisite for floor plate differentiation and suggest parallels between the development of the floor plate in amniote and anamniote embryos

An Investigation of the Deuteration of Mandelic Acid With an Additional Paper on the Measurement of Acidity at Temperatures Over 100&deg

The deuteration of optically active mandelic acid was investigated by shaking it in a sealed, evacuated tube under various conditions of temperature, and with different catalytic agents. The effect of acid, base, and platinum catalysts was examined, and in each case the degree of exchange occurring in the alpha position of the mandelic acid was correlated with the simultaneous change in its optical activity. The results indicated that with a basic catalyst present, the reaction occurred by a racemisation mechanism, an attacked molecule having an equal chance of retaining its configuration or undergoing an inversion. The platinum-catalysed exchange in acid solution was more complex, with both racemisation and retention mechanisms playing a part. With no catalyst present, racemisation of the acid occured, but without a corresponding exchange. In presence of platinum, the benzene ring, as well as the alpha hydrogen atom, was deuterated. These conclusions were confirmed by resolutions of the deuterated mandelic acid, when the observed deuterium contents of the resolved fractions were found to be in good agreement with the figures calculated assuming the mechanisms postulated for the first part of the experiment. The resolution also showed that alpha hydrogen exchange and nuclear deuteration were quite independent. Mechanisms for the various reactions have been suggested, and involve an Initial ionisation of the alpha hydrogen atom, either on the catalyst surface, or under the influence of a basic catalyst. The racemisation without exchange is considered to occur by a mechanism involving an initial fission of the bond between the alpha carbon atom and the carboxyl group

A General Equilibrium Model of Environmental Option Values

In this paper we consider the option value of the environment employing a stochastic general equilibrium growth model. In our model, as in existing studies, because of irreversibility, the environment has significant real option value. However, unlike the existing literature, the value of the environment is endogenously determined in our general equilibrium setting. In our model, the elasticity of substitution between the environment and consumption not only has quantitative effects but also qualitative effects on the option value of the environment and the optimal allocation of land. We also show that the volatility of the exogenous shock process has quantitatively significant effects on the size of the option value which has important implications for the practical estimation of environmental option values

Do Bubbles have an Explosive Signature in Markov Switching Models?

We investigate nine data series previously identified as containing bubbles using Bayesian Markov switching models. Nearly all series appear to display strong regime switching that could possibly be induced by `bubble' processes, but in each case the type of model that best describes each price differs substantively. We pay particular attention to whether these series contain transient explosive roots, a feature which has been suggested to exist in several bubble formulations. Bayesian model averaging is employed which allows us to average across a range of submodels, so that our empirical findings are not based on only one well performing model. We show that explosive regimes may exist in many submodels, but only when the flexibility of the model is limited in other important respects. In particular, when Markov switching models allow for switching levels of error variance, explosive root regimes occur in only a minority of the series

Do Consumers Really Care? An Economic Analysis of Consumer Attitudes Towards Food Produced Using Prohibited Production Methods

Taking account of consumer preferences for food produced using prohibited production methods matters if welfare of analysis of potential trade deals is to be considered meaningful. To enable this to occur it is necessary to appropriately examine consumer preferences. To this effect, we report the findings from four discrete choice experiments examining UK consumer attitudes for food produced using several agricultural production methods currently prohibited in the UK e.g., chlorine washed chicken. Our results reveal negative preferences for these forms of agricultural production methods whereas EU food safety standards are highly valued. Willingness to pay estimates indicate that the positive values for food safety are frequently greater than the negative values placed on prohibited food production methods. Similarly, UK country of origin was highly valued but organic production was less valued. The implications of these results and the use of stated preference estimates in economic modelling underpinning trade negotiations are discussed

An Economic Analysis of Twitching Behaviour and Species Rarity

Avid birdwatchers, or ‘twitchers’, expend a considerable amount of money and time pursuing viewing experiences of rare or vagrant species. By vagrant species we mean a species found outside its normal range/distribution. To enhance our understanding of this form of behaviour, we present results from a UK survey of twitchers. First, we examine the relationship between cost and rarity based on actual viewing experiences. Our statistical results reveal that the relationship between cost and rarity is positive and very inelastic. Second, we present results from a hypothetical Best-Worst Scaling exercise examining aspects of species rarity. We find that rarity is a more nuanced construct than simply the frequency with which a vagrant species has appeared. Our results provide insights into the meaning of rarity, as well as the economic value attach to it and why

Is Radiative Forcing Cointegrated with Temperature? A Further Examination Using a Structural Time Series Approach

This paper re-examines the long-run relationship between radiative forcing (including emissions of carbon dioxide, sulphur oxides, methane, and solar radiation) and temperatures from a structural time series modeling perspective. We assess whether forcing measures are cointegrated with global temperatures using the structural time series approach

Nutrition transition and changing food preferences in India

We present empirical evidence on how changes in food preferences have contributed to nutrition transition, where the dietary pattern of households shifts away from traditional staples. Using household level time series cross-section survey data for India, we estimate time varying demand elasticities, revealing evidence of the declining importance of cereals in Indian household diets. The estimates show that Indian demand for cereals has become more income inelastic and price elastic. We also find that cereals are a substitute rather than a complement to animal products in household diets. Since changes in elasticities can only be attributed to variation in utility parameters, this indicates that cereals are losing favour with Indian households. These findings have implications for Indian food policy design and implementation