The Collective Action as Potential Driver of Bottom-up Reconfiguration from Captive to Relational Value Chain : the Case Study of the Northern District in Sierra Leone

In recent decades, the increasing growth rate of the African cashew business has involved a large number of corporate actors such as global retailers, processors and exporters in cashew supply networks. The increasing role of agro-food supply chains enables African countries to enhance their position in global markets and to sustain local development and growth, by encouraging a higher market-orientation in the governance of global value chains. In this paper, an exploratory analysis based on a questionnaire involving 319 smallholder farmers in the North of Sierra Leone is conducted in order to explore the role of collective action in driving the potential bottom-up reconfiguration of cashew value chain. A change from captive to relational governance is expected to positively support the local industry upgrading, to reduce transaction costs and information asymmetries, and to increase the local development and growth by enhancing employment creation and poverty alleviation

Typical Products and Marketing Strategies for Sicilian Olive Oils

The research analyses the Sicilian Protected Designation of Origin (PDO) olive oils chain in the contest of Sicilian rural development and as an instrument aimed to add value to agricultural production. Olive oil is a characteristic product of Southern Italian and Mediterranean agriculture and one of the main agro-food production of some Southern Italian Regions; it plays a leading role in Sicilian agricultural production and it can be considered the mort representative typical products of Sicilian rural environment, rural culture and eno-gastronomic tradition. Origin labelled oils are a small but important part of extra virgin olive oil chain process. Even if the present production areas of Sicilian PDO olive oils cover a large part of the region and almost the whole region constitutes a wide quality oil production area, the sold amounts of these products result still lower than the potential. To propose a strategy aimed to improve Sicilian typical oil market, we analysed demand and supply, opportunities and threats. Improving proposals are classified according to supply chain subjects and marketing mix steps.Marketing,

A Bayesian High-Frequency Estimator of the Multivariate Covariance of Noisy and Asynchronous Returns

A multivariate positive definite estimator of the integrated covariance matrix of noisy and asynchronously observed asset returns is proposed. We adopt a Bayesian Dynamic Linear Model where microstructure noise is interpreted as measurement error, and asynchronous trading as missing observations in an otherwise synchronous series. Missing observations are treated as any other parameter, as typical in a Bayesian framework. An augmented Gibbs algorithm is used since all full conditionals are available and its convergence and robustness are discussed. A realistic simulation study compares our estimator with existing alternatives, under different liquidity and microstructure noise conditions. The results suggest that our estimator is superior in terms of RMSE particularly under severe conditions, such as portfolios of assets with heterogeneous liquidity and high level of microstructure noise. The application to the empirical dataset of ten tick-by-tick stock price series confirms the simulation result

Towards a phase-field model for thin structures: a coarse-grained constitutive law for brittle fracture of beams

Damage gradient models approximate fracture mechanics using a modulation of the material stiffness. To this aim a single scalar field, the damage, is used to degrade as a whole the elastic energy. If applied to the structural models of beams and shells, where the elastic energy is the sum of the stretching and bending contributions, a similar approach is not able to capture some important features. For instance, the coupling between axial and bending strains induced by cracks non-symmetric with respect to the center line is completely missed. In this contribution, we deduce a constitutive law for a beam having a crack non-symmetric with respect to the center line. To achieve this, we perform an asymptotic coarse-grained procedure from a 2D problem, using a sharp interface model. We deduce a homogenized 1D elastic energy, coupling the axial and bending strains, the constitutive parameters of which depend in a different way on the crack depth and we state how precisely they do. This should pave the way to a rational development of a phase-field gradient model for thin structures

Exploring Land Use Scenarios in Metropolitan Areas: Food Balance in a Local Agricultural System by Using a Multi-objective Optimization Model☆

Abstract The assessment of sustainability of agro-food systems is based on different and several tools. However, economic and policy implications of structural changes, such as land use change, and other modifications, for instance a different orientation or farming technique, could be mainly determined through scenario analysis. Especially in metropolitan regions, where the agricultural sector is threatened by various different pressures, a food supply adequately respondent to the demand is needed. In this sense the paper proposes the utilization of mathematical programming to assess some possible scenarios related to a higher compliance between food supply and demand. The approach is based on a linear programming model that takes into account the production and consumption dimensions in the Milan Metropolitan Area. Five scenarios are simulated, with different levels of sustainability and compliance with demand, demonstrating the potentialities of the regional agro-food system in adapting and adjusting itself to such modifications

High resolution spectroscopy in the XUV with pairs of mutually coherent and time-delayed laser harmonics

We present a Ramsey technique using high-order harmonics for high-resolution atomic spectroscopy in the extreme ultraviolet. Pairs of time-delayed and phase-coherent harmonic pulses generated by the interaction of ultrashort and intense laser pulses with a noble gas are used to study excited states of krypton