Researching European 'alternative' food networks: some methodological considerations

Recent European literature on 'alternative' food networks (AFNs) draws heavily upon an apparently accessible and diverse body of non-conventional food networks in the agro-food sector and whilst researchers frequently refer to individual examples of farmers markets, box schemes, producer cooperatives and community-supported agriculture projects, less attention is given to the methodological processes that facilitate the identification and examination of these networks. From the preliminary stages of a research project focusing on examples of AFNs, ² this paper examines the process of operationalizing AFNs research and reviews the difficulties associated with identifying, comparing and characterizing AFNs.     

Stability and accuracy of waterhammer analysis

The first-order accurate explicit finite-difference scheme based on the method of characteristics (MOC) has been widely used for the analysis of waterhammer in pipelines. For the stability of this scheme, the Courant condition has been developed by neglecting the nonlinear terms. When the friction loss term is large, this scheme becomes unstable even if the Courant stability is satisfied. In this paper, the stability and accuracy including friction are investigated by systematically analyzing typical piping systems over a wide range of parameters and empirical stability limits are presented for practical applications. In addition, the suitability of the implicit finite difference method for transient analysis is investigated.     

Effect of stiffness variability on the response of isolated structures

Results are presented of an investigation, the objective of which was to determine the relationship between the stiffness variability of the bearings of an isolation system and the response variability of the structure. The system is modeled as a rigid, rectangular structure that is free to translate and rotate. The isolation system consists of N isolation bearings arranged in a rectangular pattern, each with a stiffness k_i that is an independent, normally distributed, random variable. Response spectrum analysis is used to obtain the analytical solution for the structure response. Approximate closed‐form expressions are obtained for the variance of the centreline displacement, rotation, corner displacement and base shear, that are in terms of the variability of the isolator stiffness, aspect ratio of the structure, and the number and layout of isolation bearings. Results show that the standard deviation of the centreline displacement and base shear decrease with increasing number of isolation bearings, and are independent of the aspect ratio and layout of isolators, and in all cases are less than 1/4 the standard deviation of the isolator stiffness. The standard deviation of the corner displacement is a function of all of the system parameters, and is bounded below by the standard deviation of the centreline displacement and above by the standard deviation of a bar aligned perpendicular to the direction of ground motion with m isolation bearings distributed along the length. The approximate expressions are shown to be in good agreement with the results of Monte Carlo simulations. The results should be of use to designers of isolated structures and manufacturers of isolation systems, in assessing the significance of stiffness variability on the response of the isolated structure. Copyright © 2000 John Wiley & Sons, Ltd.     

'Hell on earth and paradise all at the same time': the production of smallholding space in the British countryside

Summary This paper begins to develop an analysis of the geography of smallholding, as a contribution to developing interest in cultural geographies of farming and the nature of the 'post-productivist' countryside. The paper uses evidence from a survey of UK smallholders to suggest that they are in a paradoxical position in relation to ideas about 'real' farming, production and consumption, leisure and work. Smallholder identity is revealed as constituted through ideas about 'nature', food, family, community, work and rural space. The paper concludes by suggesting a framework of ideas for future intensive research into smallholding and its links with farming cultures and rural social and cultural change.     

Property matters: Agricultural restructuring and changing landlord-tenant relationships in England

Little research has been conducted on the restructuring activities of tenant farmers in response to changing tenancy legislation and recent CAP reforms. This paper examines the geography of farm tenancy agreements in England since 1995 and presents some findings from postal and telephone surveys on the possible future business trajectories of tenant farmers and the changing nature of landlord-tenant relationships. A clear north-south divide is identified in terms of farm tenancy agreements and a complex array of different tenancy agreements is demonstrated. The relationships between landlords and tenants are changing and the increasing variety of agreements provides evidence of a more fluid (post-feudal) system of agricultural leases. Nevertheless, high levels of uncertainty and negativity characterise tenant farmers’ views on the impacts of CAP reforms. Crucially, the very identity of a tenant farmer is changing, towards an owner-occupier who rents additional land, and there is an urgent need for more detailed research on the ‘consequential geographies’ of farm property rights and the changing nature of landlord-tenant relationships.     

Comment on Fofonoff's mode

Abstract

Recently Merkine, Mo and Kalnay (1985) have re-examined the possible existence of Fofonoff's (1954) steady free inertial solution and the role of Fofonoff's mode in numerical circulation models after Veronis (1966). Merkine et al. conclude that the Fofonoff mode does not occur, that such a mode would be barotropically unstable and that resemblances between numerical circulations and Fofonoff's mode are more dependent upon the natures of forcing and dissipation. On the contrary, I suggest that Fofonoff's mode very naturally does emerge and that forcing and dissipation only impede the full realization of Fofonoff's mode. Moreover, statistical mechanical arguments from Salmon, Holloway and Hendershott (1976) show that the Fofonoff mode is expected to co-exist with a transient eddy field whose statistics are in equilibrium with the mode; thus bartotropic instability does not argue for non-realization of Fofonoff's mode.     

Feature. The Mam Tor landslip: still moving after all these years

The Mam Tor area (5 km west of Castleton, Derbyshire) is a perennial favourite for field visits by school and university parties and enthusiastic amateurs. As well as displaying the local stratigraphic relationships between the lower Carboniferous limestones and the overlying Edale mudstone/Mam Tor beds sequence, the major slope failure of the eastern side of Mam Tor is spectacularly developed.