Path dependence, its critics and the quest for ‘historical economics’

The concept of path dependence refers to a property of contingent, non- reversible dynamical processes, including a wide array of biological and social processes that can properly be described as 'evolutionary.' To dispell existing confusions in the literature, and clarify the meaning and significance of path dependence for economists, the paper formulates definitions that relate the phenomenon to the property of non-ergodicity in stochastic processes; it examines the nature of the relationship between between path dependence and 'market failure,' and discusses the meaning of 'lock-in.' Unlike tests for the presence of non-ergodicity, assessments of the economic significance of path dependence are shown to involve difficult issues of counterfactual specification, and the welfare evaluation of alternative dynamic paths rather than terminal states. The policy implications of the existence of path dependence are shown to be more subtle and, as a rule, quite different from those which have been presumed by critics of the concept. A concluding section applies the notion of 'lock-in' reflexively to the evolution of economic analysis, suggesting that resistence to historical economics is a manifestation of 'sunk cost hysteresis' in the sphere of human cognitive development.path dependence, non-ergodicity, irreversibility, lock-in, counterfactual analysis

Recent advances on physical technologies for the pretreatment of food waste and lignocellulosic residues

The complete deployment of a bio-based economy is essential to meet the United Nations??? Sustainable Development Goals from the 2030 Agenda. In this context, food waste and lignocellulosic residues are considered lowcost feedstocks for obtaining industrially attractive products through biological processes. The effective conversion of these raw materials is, however, still challenging, since they are recalcitrant to bioprocessing and must be first treated to alter their physicochemical properties and ease the accessibility to their structural components. Among the full pallet of pretreatments, physical methods are recognised to have a high potential to transform food waste and lignocellulosic residues. This review provides a critical discussion about the recent advances on milling, extrusion, ultrasound, and microwave pretreatments. Their mechanisms and modes of application are analysed and the main drawbacks and limitations for their use at an industrial scale are discusse

Force-free magnetic fields in resistive magnetohydrostatics

AbstractIt is proven that, in resistive magnetohydrostatics, the only force-free magnetic fields B which remain force-free in time are those for which α is constant in space and time, where α is defined by ▽ × B = αB