M. J. Martinez

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Lake Tota (Boyaca, Colombia) supplies water for human consumption, agriculture and industry for more than 500.000 people. Oxadixyl and Tebuconazole are fungicides used in onion crops in the lake catchment area. The mobility of pesticides in soil, bioavailability and transfer to other environmental compartments depend on sorption and desorption kinetics and(More)
We have designed a special dynamometer for measuring mouse forelimb muscle strength and endurance. The device exploits a mouse's tendency to grasp a horizontal metal bar while suspended by its tail. A threshold value for the magnitude and duration of force that the mouse can exert is obtained by first allowing the animal to grasp the bar and then applying a(More)
The analysis of finite mixture models for exponential repeated data is considered. The mixture components correspond to different unknown groups of the statistical units. Dependency and variability of repeateddata are taken into account through randomeffects. For each component, an exponential mixed model is thus defined. When considering parameter(More)
Tebuconazole is a fungicide used on onion crops (Allium Fistulosum L) in Colombia. Persistence of pesticides in soils is characterized by the half-life (DT50), which is influenced by their chemical structure, the physical and chemical properties of the soil and the previous soil history. Based on its structural and chemical properties, tebuconazole should(More)
To obtain profitable yields in olive groves, residual preemergence herbicides are applied in October or November before the winter rains, and before the winter annual weeds germinate. Simazine, one of the herbicides most used for weed control in olive groves, has recently been banned. Oxyfluorfen is presented as a good alternative to simazine in olive(More)
In this paper, we consider the flow of an incompressible fluid in a deformable porous solid. We present a mathematical model using the framework offered by the theory of interacting continua. In its most general form, this framework provides a mechanism for capturing multiphase flow, deformation, chemical reactions and thermal processes, as well as(More)
Expanding interest in enhanced subsurface natural resource recovery and carbon sequestration motivates study of reacting flows in porous media. In this work, we examine the case of reaction products that increase or decrease the viscosity of the fluid. Parallel reactant streams flow through porous media and react transversely along the centerline. We(More)
The Hipparcos catalog provides a reference frame at optical wavelengths for the new International Celestial Reference System (ICRS). This new reference system was adopted following the resolution agreed at the 23rd IAU General Assembly held in Kyoto in 1997. Differences in the Hipparcos system of proper motions and the previous materialization of the(More)