Physicochemical and microbiological monitoring of anaerobic digestion at laboratory and low cost tubular digester

The aim of this work was to use an inexpensive technique, such as the most probable number, MPN to quantitatively and qualitatively examine microbial groups in anaerobic digestion, AD of cattle manure, CM. Different diluents and mixing ratios were evaluated in 100 mL reactors using biomethane potential, BMP, as output variable. MPN tests were performed to samples from a 23 L tank and 6.5 m³ low-cost tubular digester, LCTD. To monitor LCTD stability, volatile solids, VS, specific methanogenic activity, SMA, pH, volatile fatty acids, VFA, and chemical oxygen demand, COD were measured. Microbial characterization highlighted the optimal population essential to initiate the anaerobic digestion process. Bacteria domain were predominant over Archaea, with average abundance values of 78% and 22%, respectively. SMA of 0.0486 g COD g^-1 SV d^-1 was obtained at laboratory-scale and LCTD reached 83% of this value. Conditions selected are cost-effective to establish a biodigester in rural areas.

Biomechanics of microliths manufacture: a preliminary approach to Neanderthal's motor constrains in the frame of embodied cognition

The systems of perception and action of the brain appear as important constraining factors in human evolution under current models of embodied cognition. In this view, the emergence of certain items in the archeological record is not necessarily subsequent to the emergence of a 'symbolic' mind, but instead to the appearance of the sensory-motor systems enabling that behavior. One of the products normally absent in pre- Homo sapiens species is the standardized microlith, whose production seems very demanding for the hand due to their small size and need for fine craft. In the present study, we provide preliminary empirical evidence that the biomechanical requirements of microliths manufacture made this industry difficult to achieve by Neanderthals. The biomechanical parameters of the human hand in the manufacture of microliths are here explored in two individuals with different degrees of expertise. The figures obtained in this manner are subsequently contrasted and extrapolated to Neanderthal's hand anthropometric data, as obtained from the available literature. Results indicate that Neanderthals would exhibit lower efficiency than modern humans as a consequence of their smaller hands and shorter arms, resulting in a smaller area to distribute forces and an increased mechanical stress in the microlith manufacturing processes. This might be a plausibly contributing factor for precluding microlith production in Neanderthals on noticeable scales, in consonance with the archeological record.

[Correlation between myocardial perfusion and coronary angiography]

Determining the severity of coronary heart disease is of great importance to the cardiologist. There is a very good correlation between the severity of coronary heart disease and perfusion abnormalities to the myocardium as determined by radioisotope studies. We present our experience with forty (40) cases of ischemic heart disease diagnosed with sestamibi and its correlation with the obstruction of the coronary arteries by angiography. There is good correlation between the sestamibi findings and the coronary artery angiography obstructions and our findings concur with those published in the literature, which is between 75-85%.