Chemotaxis and optimization

Chemotactic behavior of bacteria as reported by Delbrück, Adler and MacNab and Koshland is modelled as an optimization process. For equiconcentration surfaces that are concentric spheres the expected travel time from an initial point to the center is determined analytically. In addition, cylindrical equiconcentration surfaces are discussed. Refinements of the process to test various hypotheses about thresholds, tumbling and overshoot are also indicated.     

Infant responsivity to curvature.

The reactions of 112 10-month-old male infants to the property of curvature were examined using a habituation paradigm with lever pressing as an instrumental response. 4 levels of curvature (straightt line, minimal curve, moderate curve, large curve) each served as a standard (habituation) stimulus and as a transformation stimulus in 9 separate experimental conditions. Results revealed a greater initial dishabituation of reinforced instrumental responding in those conditions crossing the curved/straight boundary; furthermore, this initial dishabituation was sustained throughout the transformation phase of the experiment in those conditions which involved changes from straight to curved, but not curved to straight. Results are interpreted as implying a special attention-recruiting value for curvature in 10-month old infants.     

Worldwide impacts of atmospheric vapor pressure deficit on the interannual variability of terrestrial carbon sinksOA

Interannual variability of the terrestrial ecosystem carbon sink is substantially regulated by various environmental variables and highly dominates the interannual variation of atmospheric carbon dioxide(CO₂) concentrations.Thus,it is necessary to determine dominating factors affecting the interannual variability of the carbon sink to improve our capability of predicting future terrestrial carbon sinks.Using global datasets derived from machine-learning methods and process-based ecosy...