Testing for Adverse Selection into Private Medical Insurance

We develop a test for adverse selection and use it to examine privatehealth insurance markets. In contrast to earlier papers that consider apurely private system or a system in which private insurance supplementsa public system, we focus our attention on a system where privately fundedhealth care is substitutive of the publicly funded one. Using a model ofcompetition among insurers, we generate predictions about the correlationbetween risk and the probability of taking private insurance under bothsymmetric information and adverse selection. These predictions constitutethe basis for our adverse selection test. The theoretical model is also usefulto conclude that the setting that we focus on is especially attractive to testfor adverse selection. Using the British Household Panel Survey, we findevidence that adverse selection is present in this market. We develop a test for adverse selection and use it to examine privatehealth insurance markets. In contrast to earlier papers that consider apurely private system or a system in which private insurance supplementsa public system, we focus our attention on a system where privately fundedhealth care is substitutive of the publicly funded one. Using a model ofcompetition among insurers, we generate predictions about the correlationbetween risk and the probability of taking private insurance under bothsymmetric information and adverse selection. These predictions constitutethe basis for our adverse selection test. The theoretical model is also usefulto conclude that the setting that we focus on is especially attractive to testfor adverse selection. Using the British Household Panel Survey, we find evidence that adverse selection is present in this market

Testing for Asymmetric Information in Private Health Insurance

We test for asymmetric information in the UK private health insurance (PHI) market. In contrast to earlier research that considers either a purely private system or one where private insurance is complementary to public insurance, PHI is substitutive of the public system in the UK. Using a theoretical model of competition among insurers incorporating this characteristic, we link the type of selection (adverse or propitious) with the existence of risk-related information asymmetries. Using the British Household Panel Survey, we find evidence that adverse selection is present in the PHI market, which leads us to conclude that such information asymmetries exist

Implementation algorithm of a generalised plasticity model for swelling clays

A multi-mechanism generalisation of Sloan’s integration scheme for elasto-plastic laws has been developed in order to implement a double structure model for expansive clays into a FE code. The constitutive model is built on a conceptual approach for unsaturated expansive soils in which the fundamental characteristic is the explicit consideration of the two pore levels often present in expansive clays. The distinction between macro and microstructure provides the opportunity to take into account the dominant phenomena that affect the behaviour of each structural level and the main interactions between them. The model is formulated using concepts of classical and generalised plasticity theories. The integration scheme proposed can deal with the two plastic mechanisms defined in the model and can incorporate the effects of strains, suction and temperature in the stress integration process. A large scale heating test is analysed to check the capabilities of the implemented model to simulate an actual problem involving complex thermo-hydro-mechanical stress paths. The performance of the model has been very satisfactory and the proposed integration scheme has proved to be robust and efficient in solving a highly non-linear coupled problem

Effect of thermo-coupled processes on the behaviour of a clay barrier submitted to heating and hydration

The storage of high level radioactive waste is still an unresolved problem of the nuclear industry, being geological disposal the most favoured option and, naturally, the one requiring the strongest geo-mechanical input. Most conceptual designs for the deep geological disposal of nuclear waste envisage placing the canisters containing the waste in horizontal drifts or vertical boreholes. The empty space surrounding the canisters is filled by an engineered barrier often made up of compacted swelling clay. In the barrier and the near field, significant thermo-hydro-mechanical (THM) phenomena take place that interact in a complex way. A good understanding of THM issues is, therefore, necessary to ensure a correct performance of engineered barriers and seals. The conditions of the bentonite in an engineered barrier for high-level radioactive waste disposal are being simulated in a mock-up heating test at almost scale, at the premises of CIEMAT in Madrid. The evolution of the main Thermo-Hydro-Mechanical (THM) variables of this test are analysed in this paper by using a fully coupled THM formulation and the corresponding finite element code. Special emphasis has been placed on the study of the effect of thermo-osmotic flow in the hydration of the clay barrier at an advanced staged of the experiment.Peer ReviewedPostprint (published version

THM and reactive transport analysis of expansive clay barrier in radioactive waste isolation

A fully coupled formulation combining reactive transport and an existing thermo‐hydro‐mechanical (THM) code is briefly described. Special attention has been given to phenomena likely to be encountered in clay barriers used as part of containment systems of nuclear waste. The types of processes considered in the chemical formulation include hydrolysis, complex formation, oxidation/reduction reactions, acid/base reactions, precipitation/dissolution of minerals and cation exchange. Both kinetically controlled and equilibrium‐controlled reactions have been incorporated. The formulation has been implemented in the finite element code CODE_BRIGHT. An application is presented concerning the performance of a large scale in situ heating test simulating high‐level nuclear waste repository conditions

Thermo-hydro-mechanical model of the Canister Retrieval Test

The paper presents a 2-D axisymmetric numerical simulation of the Canister Retrieval Test (CRT). The main objectives of this analysis are the study of the canister–buffer and buffer–host rock interfaces; and the evaluation of the mathematical models used to predict the THM behaviour of the buffer and interface. The THM simulation was performed using the finite element program Code-Bright. The constitutive law adopted to represent the mechanical behaviour of bentonite and pellets is the Barcelona Basic Model (BBM) with a non-linear elastic component accounting for swelling. A joint element with a non-linear elastic mechanical law was implemented in the code for the simulation of the opening–closure of the interface canister–buffer. The formulation of this element also incorporates appropriate thermal and hydraulic laws. The evolution of temperatures, relative humidities and stresses recorded during the test were compared with the simulation results. Comparing the results measured in situ with the results of numerical analysis shows that the formulation used is able to reproduce satisfactorily the phenomena involved in the test as well as their interactions. In addition, the final dry density and degree of saturation measured in samples of bentonite and pellets extracted during the test dismantling were also in agreement with the calculated values

Modelling thermo-hydro-mechano-chemical interactions for nuclear waste disposal

A fully coupled thermo-hydro-mechano-chemical (THMC) formulation is described in this paper. Special attention is paid to phenomena likely to be encountered in clay barriers used as engineered barriers in the disposal of nuclear radioactive waste. The types of processes considered in the chemical formulation include hydrolysis, complex formation, oxidation/reduction reactions, acid/base reactions, precipitation/dissolution of minerals and cation exchange. Both kinetics- and equilibrium-controlled reactions are incorporated. The formulation is implemented in a numerical code. An application is presented concerning the performance of a large-scale in-situ heating test simulating high-level radioactive waste repository conditions

Fate of MTBE and DCPD Compounds Relative to BTEX in Gasoline-Contaminated Aquifers

The aim of this communication is to provide preliminary results on MTBE monitoring, and at the same time to propose some new tracers of gasoline pollution in groundwater. An overview is presented on benzene-toluene-ethylbenzene-xylene (BTEX), methyl tertiary-butyl ether (MTBE), and dicyclopentadienes (DCPD) contents in gasoline formulations. Their specific fate in gasoline-contaminated aquifers are consistent with their physical-chemical properties

Recursos genéticos del algodón en Colombia: última parte

Del cruzamiento Carolina Queen x Stoneville 213 se obtuvo la variedad ICA-Bravo que en la actualidad la siembran algunos agricultores de la Costa Atlántica, Las Tablas 4 y 5 presentan un resumen del comportamiento de la variedad Colombiana en comparación con Deltapine 16 y Deltapine Smooth Leaf. A pesar del mayor rendimiento, la variedad ICA-Bravo se retiró del mercado, para las siembras del interior del país por su alta susceptibilidad a mancha angular. No obstante, esta enfermedad no ha tenido incidencia de tipo económico que limite su utilización en la Costa Atlántica. Según el concepto de algunos agricultores, la variedad ICA-Bravo presenta las siguientes características. favorables: poca área foliar, escasa pubescencia, resistencia a la caída de la mota por el viento. Desventaja: cápsula puntiaguda