Essential structural and experimental descriptors for bulk and grain boundary conductivities of Li solid electrolytes

We present a computational approach for identifying the important descriptors of the ionic conductivities of lithium solid electrolytes. Our approach discriminates the factors of both bulk and grain boundary conductivities, which have been rarely reported. The effects of the interrelated structural (e.g. grain size, phase), material (e.g. Li ratio), chemical (e.g. electronegativity, polarizability) and experimental (e.g. sintering temperature, synthesis method) properties on the bulk and grain boundary conductivities are investigated via machine learning. The data are trained using the bulk and grain boundary conductivities of Li solid conductors at room temperature. The important descriptors are elucidated by their feature importance and predictive performances, as determined by a nonlinear XGBoost algorithm: (i) the experimental descriptors of sintering conditions are significant for both bulk and grain boundary, (ii) the material descriptors of Li site occupancy and Li ratio are the prior descriptors for bulk, (iii) the density and unit cell volume are the prior structural descriptors while the polarizability and electronegativity are the prior chemical descriptors for grain boundary, (iv) the grain size provides physical insights such as the thermodynamic condition and should be considered for determining grain boundary conductance in solid polycrystalline ionic conductors

Seasonal Variation in Hemoglobin Concentration in Non-Agricultural Populations under Various Climatic Conditions

Hemoglobin concentrations and red blood cell counts were repeatedly determined once every four seasons of the year in 324 apparently healthy adults (181 men and 143 women) in 15 groups at 7 locations (from the northern-most at Sapporo to the southern-most at Bangkok) in 4 Asian countries of different cli­matic conditions. Work intensity of the subjects was essentially constant through­out the year. Both hematological variables were significantly lower in summer than in winter in the areas where seasonal variation in the outdoor temperature was pronounced, i.e., higher than 20°C in summer and lower than 5°C in winter. There was essentially no seasonal change in hemoglobin concentration or red blood cell counts where the temperature stays between 25 and 30°C throughout the year. The seasonal variation in hemoglobin concentration and red blood cell counts appeared to be due to temperature and not to relative humidity. When the work rooms were air-conditioned, no seasonal change in the blood variables of the subjects was observed