Can the world feed itself? Some insights from growth theory

This paper develops a two-sector growth model incorporating the essential distinguishing features of agriculture, including the reliance of production on a natural resource base as well as on industrially produced inputs, the low income elasticity of demand for food and the life-sustaining function of food consumption. In this framework, the ability of an economy to supply an adequate supply of food to a growing population can be related to the existence of a steady state. This property is used to define a simple analytical criterion upon which to assess the long-term food situation of a closed economy. This sustainability condition relates all the dynamic parameters of the economy: rates of technological change in the two sectors, rate of population growth and rate of land degradation. The condition is used to highlight the technological characteristics in agriculture conducive to sustainability and to assess empirically the food situation of a number of countries. Although no global food crisis appears to be looming ahead, the data suggest that sub-Saharan Africa is likely to increase its food dependence in the future.Food Security and Poverty,

GROWTH PATTERN, SUSTAINABILITY AND TRADE IN A LAND CONSTRAINED ECONOMY

This paper develops a two-sector model of growth where agriculture is considered explicitly. Key features of the model include: the reliance of agricultural production on a fixed but degrading resource base, the use by the farm sector of industrially produced inputs and differing rates of technological progress in the two sectors. On the demand side, the low income elasticity for food as well as the life-sustaining function of food consumption are recognized. In this simplified framework, the sustainability of growth can be related to the existence of a steady state reflecting the ability of the economy to feed its population. This property is used to identify the characteristics within and outside of agriculture conducive to the sustainability of a land-constrained economy. The empirical application identifies sub-Saharan Africa as the region of the world facing the most important challenges in terms of sustainability. The second part of the paper makes use of the transitional properties of the model to analyse the relationship between agricultural productivity and growth performance. For a closed economy, the model unambiguously supports the view that high agricultural productivity is conducive to fast growth and industrialization. Once the country is allowed to trade, however, the relationship becomes more complex, but a numerical experiment illustrates how trade liberalization can accelerate the growth of a country poorly endowed in agricultural resources.sustainability, agriculture and growth, dynamic general equilibrium model, International Development, O41, O13, F11,

Closing a Loophole in Factorization Proofs

We address the possibility in factorization proofs that low-energy collinear gluons can couple to soft gluons.Comment: 3 pages, 5 figures, contribution to the proceedings of Quark Confinement and the Hadron Spectrum I

Photon locking

A novel observation of photon locking—the optical analog of spin locking—is reported, demonstrating the applicability of phase-coherent pulse sequences. The experiments are reported for the optical transition of iodine gas at 589.7 nm using the pulse sequence XYX-XYX̄. Locking decay rates are presented as a function of pressure and compared with optical dephasing (echo-decay) rates

DETERMINANTS OF FOOD PRICE INFLATION IN FINLAND

The agricultural commodity crisis of 2006-8 and the recent evolution of commodity markets have reignited anxieties in Finland over fast-rising food prices and food security. Although the impact of farm commodity price shocks on the final consumer is mitigated by a large degree of processing as well as the complex structure of the food chain, little is known about the strength of the linkages between food markets and input markets. Using monthly series of price indices from 1995 to 2010, we estimate a vector error-correction (VEC) model in a co-integration framework in order to investigate the short-term and long-term dynamics of food price formation. The results indicate that a statistically significant long-run equilibrium relationship exists between the prices of food and those of the main variable inputs consumed by the food chain, namely agricultural commodities, labour, and energy. When judged by the magnitude of long-run pass-through rates, farm prices represent the main determinant of food prices, followed by wages in food retail and the price of energy. However, highly volatile energy prices are also important in explaining food price variability. The parsimonious VEC model suggests that the dynamics of food price formation is dominated by a relatively quick process of adjustment to the long-run equilibrium, the half life of the transitional dynamics being six to eight months following a shock.Demand and Price Analysis,

An Assessment of the Potential Consumption Impacts of WHO Dietary Norms in OECD Countries

The member countries of the World Health Organization (WHO) have recently endorsed its Global Strategy on Diet, Physical Activity and Health. The strategy emphasizes the need to limit the consumption of saturated fats and trans fatty acids, salt and sugars, and to increase consumption of fruits and vegetables in order to combat the growing burden of non communicable diseases. Adherence to the norms recommended by the WHO would call for major changes in the consumption, production and trade of several key food products and several sectors of the food industry have expectedly raised serious concerns about the potential impact of these norms on their future growth prospects. This paper attempts a broad quantitative assessment of the consumption impacts of these norms in OECD countries using a mathematical programming approach. We find that adherence to the WHO norms would involve a significant decrease in the consumption of vegetable oils (30%), dairy products (28%), sugar (24%), animal fats (30%) and meat (pig meat, 13.5%, mutton and goat 14.5%) and a significant increase in the human consumption of cereals (31%), fruits (25%) and vegetables (21%). The paper also explains the apparent dilemma that some OECD countries face when simultaneously trying to liberalise agricultural markets and promote healthy diets.Food Consumption/Nutrition/Food Safety,

Attainability in Repeated Games with Vector Payoffs

We introduce the concept of attainable sets of payoffs in two-player repeated games with vector payoffs. A set of payoff vectors is called {\em attainable} if player 1 can ensure that there is a finite horizon $T$ such that after time $T$ the distance between the set and the cumulative payoff is arbitrarily small, regardless of what strategy player 2 is using. This paper focuses on the case where the attainable set consists of one payoff vector. In this case the vector is called an attainable vector. We study properties of the set of attainable vectors, and characterize when a specific vector is attainable and when every vector is attainable.Comment: 28 pages, 2 figures, conference version at NetGCoop 201

The Dynamical Evolution of Be star disks

We present a novel theoretical tool to analyze the dynamical behaviour of a Be disk fed by non-constant decretion rates. It is mainly based on the computer code HDUST, a fully three-dimensional radiative transfer code that has been successfully applied to study several Be systems so far, and the SINGLEBE code that solves the 1D viscous diffusion problem. We have computed models of the temporal evolution of different types of Be star disks for different dynamical scenarios. By showing the behaviour of a large number of observables (interferometry, polarization, photometry and spectral line profiles), we show how it is possible to infer from observations some key dynamical parameters of the disk.Comment: IAU 272 symposium proceedings, 3 pages, 1 figur