The yield/quality trade-off and contractual choice

This paper provides an analysis of the choice of governance mechanism in agriculture using an integrated perspective based on agency theory. The main ways of organizing agriculture are compared: spot market and incentive contract. With the analytical development of both models, it is explored that the choice of the optimal mechanism depends on initial conditions such as uncertainty, the risk aversion of the agents or the number of competitors. Moreover, according to the predictions made by the economic literature on agrarian organization, the results support the coexistence of both governance alternatives.Crop Production/Industries,

Quality and governance mode choice: a transaction cost approach to the wine industry

We analyze the relationship between product quality and governance mode choice using the results of a survey of DOC Rioja wineries. Wineries that produce high-quality wines are more likely to vertically integrate than are wineries that produce low-quality wines. Consistent with Transaction Cost Economics, we find evidence that asset specificity and uncertainty are important determinants of vertical integration. Finally, the size of the winery is also an important factor that affects governance mode choice in viticulture.quality, governance mode choice, transaction cost, Industrial Organization,

On the co-existence of spot and contract markets: an analysis of quality

The possible co-existence of spot and contract market that can emerge in the presence of quality issues with a number of growers and processors in each stage is something that has largely remained an open question in the literature. This paper is an attempt to fill this void. We use a straightforward two-stage Cournot oligopoly model with specific demand and cost functions. In the first stage, processors decide simultaneously whether or not to set an incentive contract. The second stage is the stage in which growers choose their levels of quantity and quality based on the industry structure developed in the first stage. With the help of numerical simulations we conducted the study of the equilibrium structures. Our results suggest that for a wide range of number of participants in both markets, participation in both markets constitutes a Nash equilibrium for the model.Marketing,

Double Sided Moral Hazard and Share Contracts in agriculture

This paper develops a double-sided moral hazard model of share contract in agriculture, with imperfect quality measurement by the agent and the principal, who contribute to the final good quality in terms of production effort and marketing effort respectively. Using this model, we analyse the implications of the share contract for quantity and quality, often ignored in previous analysis. With the help of a simulation exercise, we prove that the outcome-conditioned share generally weakens the agent´s incentive to make effort in quality input. This finding could explain the contractual evidence in some differentiated markets such as the wine market, where bottle-price conditioned contracts are rarely used.share-contract, double moral-hazard, quality, Farm Management,

Radiation damping for rigid foundations. Approximate expressions

The dynamic response of machine foundations was one of the first problems studied in soil dynamics with results going back to the 1930s. A number of approximations and graphical results were proposed in the 60s. In this paper we present a series of approximate expressions for the natural frequencies and effective damping of rigid masses on the surface of an elastic half space subjected to both vertical and coupled horizontal-rocking harmonic excitations. The formulas are obtained using the approximate expressions for the dynamic stiffness of circular foundations suggested by Veletsos et al [1, 2] for two different values of Poisson’s ratio of the soil. For the vertical case the expressions are only a function of the mass ratio (ratio of the mass of the foundation to an effective mass of soil) and of Poisson’s ratio. For the horizontal-rocking case they depend also on the ratio of the height of the foundation to its equivalent radius (a slenderness ratio)

Romosozumab: confusión respecto a sus indicaciones

El romosozumab es, sin duda, un excelente fármaco para el tratamiento de la osteoporosis. No obstante, su elevado precio, muy superior al de los fármacos antirresortivos, hizo que inicialmente se aceptara sin dificultad que su indicación se limitase a pacientes con un riesgo de fractura particularmente elevado. Sin embargo, la aplicación de esta idea en la práctica se ha encontrado con algunos problemas. En primer lugar, para describir tal indicación se han utilizado términos distintos ("riesgo muy alto", "riesgo alto", "osteoporosis grave"), el significado concreto de cada uno de los cuales, además, es diferente para unos y otros autores. Por otra parte, y sin un fundamento científico suficiente, se han ido introduciendo conceptos que pretenden ampliar las indicaciones del fármaco hasta prácticamente proponer la generalización de su uso ("riesgo inminente", comienzo del tratamiento de la osteoporosis con anabólicos de forma universal o cuasi-universal). Todo ello ha generado confusión en el médico prescriptor, y ha dado lugar a que las autoridades sanitarias hayan impuesto para su uso normas que han resultado demasiado restrictivas. En el artículo se desarrollan estas ideas -y algunas otras- con detall

The Influence of Soil Composition on Stormwater Retention and Runoff in Green Roofs at Portland State

The purpose of this study is to determine what soil composition is best for green roofs at Portland State; we aim to compare the current soil to the original substrate, to measure which composition retains the most water, and which filters out the most pollutants in stormwater runoff. Five different soil compositions were tested — original, current, layered mixed, solid mixed, and potting soils — and 1,000mL of high and low intensity rainfall (in/hr) was simulated for each of the mixtures. Water was allowed to filter through the soils for a predetermined time (10min for a high application rate and 20min for a low application rate), and runoff water was collected in a graduated cylinder. Contaminant levels in the simulated stormwater runoff and water retention was calculated as a percentage. Results suggest that the original soil mixture retains more water than the current soil mixture during low intensity rainfall, but falls short during high intensity events. All soils were outperformed by potting soil in terms of retention regardless of application rate. Inversely, potting soil had the worst environmental impact for pollutant runoff. More studies need to be done to determine the best composition of soil for Portland State’s green roofs

Response of a high-speed train travelling over a long and high-pier viaduct during moderate earthquakes

This contribution presents the results of numerical simulations in which a high-pier viaduct under lateral and vertical non-stationary spatially variable seismic ground motions is crossed by an articulated high-speed train at several speeds. The spectral representation method is employed to generate the required number of acceleration time-history series at each support location of the railway viaduct studied. Wave passage, local soil conditions and loss of coherency effects have been accounted for in the simulated ground-motion time histories, with several peak ground accelerations. Train and bridge responses have been obtained by means of a non-linear dynamic interaction multibody and finite element model. An analysis of train running safety indices has been carried out. The properties of earthquakes and train speeds which may cause problems to traffic safety are detailed, as is the train derailment probability. The numerical simulation outcomes show that it is not safe for the train to travel over the studied viaduct in earthquakes with peak ground acceleration equal to 0.03 g and for train speeds above 280 km/h.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. The first author would like to acknowledge the support for this study provided by European Erasmus + project: 2020-1-ES01-KA203-083262 “Building BIM digital competences for Tertiary VET in the designing and management of construction projects”. www.BIMVET3.eu. This project is co-funded by the Erasmus + Programme of the European Union