Weather Derivatives as Risk Management Tool in Ecuador: A Case Study of Rice Production

This paper analyzes efficiency of weather derivatives as insurance instruments for rice in Ecuador. Weather derivatives were constructed for each county/season combination. Complicated weather models were estimated for the index, and a copula approach was used to get the probability distributions. We find Risk-reducing efficiency varies across county and season.agricultural risk management, index insurance, weather derivatives, copula approach, rice production, Agribusiness, Crop Production/Industries, Risk and Uncertainty, Q14, Q59,

Application of Weather Derivatives in Multi-Period Risk Management

This work is a first attempt to analyze the effect of weather derivative availability on the risk management strategies in a multi-period setting, when crop activities take place twice a year. Rice production in Ecuador is used as a case study. Numerical solutions show farmers improve their well-being by reducing their risk exposure.Weather Derivatives, Risk Management, Multi-Period., Agribusiness, Agricultural Finance, Risk and Uncertainty, Q13, Q14,

Butterfly Tachyons in Vacuum String Field Theory

We use geometrical conformal field theory methods to investigate tachyon fluctuations about the butterfly projector state in Vacuum String Field Theory. We find that the on-shell condition for the tachyon field is equivalent to the requirement that the quadratic term in the string-field action vanish on shell. This further motivates the interpretation of the butterfly state as a D-brane. We begin a calculation of the tension of the butterfly, and conjecture that this will match the case of the sliver and further strengthen this interpretation.Comment: 14 pages, 6 figures, revte

Angular dependent vortex dynamics in superconductors with columnar defects

We explore in detail the angular dependent vortex dynamics in type II superconductors with aligned columnar defects introduced by irradiation with very energetic heavy-ions. We use dc magnetization measurements deep in the vortex solid phase, and ac susceptibility near the solid-liquid transition. We show that aligned columnar defects are an excellent tool to test models for vortex dynamics, particularly if they are tilted with respect to the crystallographic axes, so their effects can be easily distinguished from those arising from mass anisotropy, sample geometry, twin boundaries and intrinsic pinning. This allows us, for instance, to use the uniaxial pinning of the columnar defects as a probe to determine the orientation of the vortices inside a bulk material, which in general is different from the orientation of the applied fields. In some aspects we have found an excellent agreement with the theoretical expectations of the Bose-glass model. The field dependence of the lock-in angle follows remarkably well the 1/H prediction over the whole temperature range of our measurements. In turn, the temperature dependence of the lock-in angle gives strong support to the concept of an effective pinning energy dominated by the entropic smearing effect. On the other hand, both our ac and dc results show that columnar defects produce effective pinning over a wide angular range, and that correlated pinning dominates the scenario for all field orientations. One consequence of this is the existence of a rich variety of vortex staircases.Comment: to be published in International Book series "Studies of High Temperature Superconductors", edited by Anant Narlikar, Nova Science Publishers, New York, Vol 49/50, (2003

Stable radiating gap solitons and their resonant interactions with dispersive waves in systems with parametric pump

We study the formation of gap solitons in the presence of parametric pump. It is shown that parametric pump can stabilize stationary solitons continuously emitting dispersive waves. The resonant interactions of the radiation and the solitons are studied and it is shown that the solitons can be effectively controlled by the radiation. In particular it is shown that the solitons can collide or to get pinned to inhomogeneities due to the interactions mediated by the resonant radiation

Classification of grasping tasks based on EEG-EMG coherence

This work presents an innovative application of the well-known concept of cortico-muscular coherence for the classification of various motor tasks, i.e., grasps of different kinds of objects. Our approach can classify objects with different weights (motor-related features) and different surface frictions (haptics-related features) with high accuracy (over 0:8). The outcomes presented here provide information about the synchronization existing between the brain and the muscles during specific activities; thus, this may represent a new effective way to perform activity recognition

Venezuela: encrucijada de un modelo de desarrollo productivo

La macroeconomía venezolana parece sana y ordenada. Sin embargo, detrás de este panorama alentador se esconde un modelo de desarrollo productivo que exhibe importantes debilidades. Al tiempo que se profundiza un patrón de especialización basado en la explotación de los recursos naturales, se pretende encadenar a un sector enclave intensivo en capital en una economía de servicios intensiva en mano de obra de baja calificación. La idea de una “economía alternativa” formada por miles de cooperativas que se mantienen gracias a los contratos con el Estado genera todo tipo de inconvenientes: pone a estas pequeñas organizaciones a merced de las oscilaciones del gasto público, desincentiva la innovación y la competencia y crea enormes redes clientelares ineficientes. En definitiva, todo descansa en un Estado fortalecido financieramente por los ingresos petroleros, que hace poco para consolidar un sector industrial capaz de responder a los retos de un mundo globalizado