Discovering and learning tool-use for fishing honey by captive chimpanzees

Wild chimpanzees commonly use sticks to fish for termites, ants or honey. This ability seems to be socially transmitted to juveniles by their mothers across generations. In a natural environment, the limited visibility of this behavior with regards to the extent of stick's insertion and about the success or failure in fishing hinders the study of the underlying learning processes. This study explores the discovery and learning of tool use for fishing honey in an artificial hive by a group of four captive chimpanzees. The discovery of tool use was accidental and coactive. The speed with which the group of experimentally naive chimpanzees discovered and learned tool use suggests that wild chimpanzees of different populations independently discovered the fishing behavior. The alpha male and his ally learned before the subordinates. Here, trial-and-error learning was, as in monkeys, the main process allowing the acquisition of the tool-use technique. However, the observation of conspecifics allowed the orientation of the experimentation by the selection of clues. As suggested by Tomaselloet al. (1987). it is the understanding of the function of the tool,i.e. the cause-effect relations between the action of the demonstrator, the type of tool and the task to accomplish which confer to chimpanzees and advantage over monkeys.     

Stereoselectivity and affinity in molecular pharmacology. III. Structural aspects in the mode of action of natural and synthetic auxins

Analysis of available potency estimates for 35 pairs of enantiomeric arylcarboxylic acids with auxin activity (flax-root-growth inhibition test) revealed extensive correlations between the activity of the more potent and less potent isomers, as well as between the log of the ratio of potencies and the log potency of the more active isomer when structurally similar analogs are compared. 5 structural subgroups were discernible (n, eudismic-affinity quotient (EAQ), r2); (1) arylpropionic acids (6, -0.36, 0.66); (2) 2-naphthoxy-carboxylic acids (6, +1.07, 0.99); (3) 1-naphthoxycarboxylic acids (3, +1.56, 0.96); (4) ortho-substituted phenoxycarboxylic acids (10, +0.97, 0.96) and (5) ortho-unsubstituted phenoxycarboxylic acids (10, +0.56, 0.70). For achiral lower homologs such as auxin itself 3-indolyl-acetic acid (IAA), phenoxyacetic acid and 1-naphthoxyacetic acid, extrapolated potencies were found to agree well with experimental values. On the basis of these observations an auxin receptor is postulated and binding arrangements are described which explain most of the experimental data available. A 3-point attachment when allowed is the only binding mode compatible with the reported data.     

A graphical method for determining inhibition constants

A new simple graphical method is described for the determination of inhibition type and inhibition constants of an enzyme reaction without any replot. The method consists of plotting experimental data as (V–v)/v versus the inhibitor concentration at two or more concentrations of substrate, where V and v represent the maximal velocity and the velocity in the absence and presence of inhibitor with given concentrations of the substrate, respectively. Competitive inhibition gives straight lines that converge on the abscissa at a point where [I]?=??K_i. Uncompetitive inhibition gives parallel lines with the slope of 1/K’_i. For mixed type inhibition, the intersection in the plot is given by [I]?=??K_i and (V–v)/v?=??K_i/K’_i in the third quadrant, and in the special case where K_i?=?K’_i (noncompetitive inhibition) the intersections occur at the point where [I]?=??K_i and (V–v)/v?=??1. The present method, the “quotient velocity plot,” provides a simple way of determining the inhibition constants of all types of inhibitors.     

Why should radiological oncology do translational research?

Radiological Oncology, like the rest of medical specialties, is beginning to provide can personalized therapies. The ongoing scientific advances enable a great degree of precision in diagnoses and therapies. To fight cancer, from a radiotherapy unit, requires up-to-date equipment, professionals with different specialties working in synchrony (doctors, physicists, biologists, etc.) and a lot of research. Some of the new therapeutic tendencies are immunotherapy, nanoparticles, gene therapy, biomarkers, artificial intelligence, etc. A new clinical paradigm in which new professional networks are inevitable is arising. The mission of translational research is to become a scientific engine in the clinical space.