Thermally Switchable Periodicities and Diffraction from Mesoscopically Ordered Materials

Two switchable, mesoscopically periodic materials were created by combining crystalline colloidal array (CCA) self-assembly with the temperature-induced volume phase transition of poly(N-isopropylacrylamide) (PNIPAM). Body-centered-cubic CCAs of hydrated, swollen PNIPAM particles Bragg-diffract infrared, visible, and ultraviolet light weakly, whereas arrays of compact shrunken particles diffract efficiently. A tunable diffracting array was also created by embedding a CCA of polystyrene spheres within a PNIPAM hydrogel that swells and contracts with temperature; thus the array lattice constant varies with temperature, and the diffracted wavelength was thermally tunable across the entire visible spectrum. These materials may find applications in many areas of optics and materials science.     

Clinical trial of efficacy of ivermectin pour‐on against gastrointestinal parasitic nematodes in silvopasturing horses

The aim of this study was to assess, by a clinical trial, the efficacy of an ivermectin‐based pour‐on treatment against gastrointestinal parasitic nematodes in naturally infected horses using 2 groups of mature indigenous Pura Raza Galega grazing mares. Faecal and blood samples were collected individually over a 21 week period. Faeces were analysed by the coprological flotation, sedimentation and migration techniques. Changes in circulating blood cells were monitored over the study period. The administration of the ivermectin suppressed the eggelimination of ascarids and pinworms throughout the study and no strongyle‐eggs were observed in the treatment group between the 3rd and 10th weeks. The numbers of red cells increased significantly after the anthelmintic therapy, and a statistical reduction in circulating leucocytes was recorded. No side effects were observed. The pour‐on ivermectin formulation was highly successful against gastrointestinal nematodes and appears to be a useful therapeutic routine for large groups of horses.     

New algebraic formulations of evapotranspiration extracted from gene-expression programming in the tropical seasonally dry regions of West Africa

Within hydrological nonlinear complex functions, taking only few parameters into the modeling process is still a challenging task. The present paper has for objective to investigate for the first time the predictive ability of the Gene-expression Programming (GEP) for modeling reference evapotranspiration (ETo) using routing weather data from the tropical seasonally dry regions of West Africa in Burkina Faso. The regions under study are located in three agro-climatic zones, Bobo Dioulasso in the Guinea Savanna zone, and Dédougou and Fada N’Gourma in the Sudan zone, and Ouagadougou in the Sudano-Sahelian Savanna zone. Several meteorological data combinations are used as inputs to the GEP to estimate ETo, and their performances are evaluated using R ² and RMSE. Statistically, it was found that GEP can be an alternative to the conventional methods, and its accuracy improves significantly up to R ² (0.979) and RMSE(0.108) when critical variables are taking into account in the model. The results revealed that GEP model is fairly a promising approach with the advantage to provide successfully simple algebraic formulas ease to use without recourse to the full set of meteorological data requirement for accurately estimate ETo in Sub-Saharan Africa regions.