Phosphate rock bioleaching

Summary Microbiological acid solutions produced byThiobacillus ferrooxidans andThiobacillus thiooxidans on pyritiferous concentrate were used to solubilize phosphate rock with a high grade in P₂O₅. Five different mixtures of pyritiferous concentrate and phosphate rock, in different proportions, were used in adequate liquid culture media. Phosphate solubilization ranged from 12% to 100% when 9K nutrients medium was used and from 12% to 89% when medium contained only 3.0g/l ammonium sulphate.     

Dinosaur diversity and the rock record

Palaeobiodiversity analysis underpins macroevolutionary investigations, allowing identification of mass extinctions and adaptive radiations. However, recent large-scale studies on marine invertebrates indicate that geological factors play a central role in moulding the shape of diversity curves and imply that many features of such curves represent sampling artefacts, rather than genuine evolutionary events. In order to test whether similar biases affect diversity estimates for terrestrial taxa, we compiled genus-richness estimates for three Mesozoic dinosaur clades (Ornithischia, Sauropodomorpha and Theropoda). Linear models of expected genus richness were constructed for each clade, using the number of dinosaur-bearing formations available through time as a proxy for the amount of fossiliferous rock outcrop. Modelled diversity estimates were then compared with observed patterns. Strong statistically robust correlations demonstrate that almost all aspects of ornithischian and theropod diversity curves can be explained by geological megabiases, whereas the sauropodomorph record diverges from modelled predictions and may be a stronger contender for identifying evolutionary signals. In contrast to other recent studies, we identify a marked decline in dinosaur genus richness during the closing stages of the Cretaceous Period, indicating that the clade decreased in diversity for several million years prior to the final extinction of non-avian dinosaurs at the Cretaceous–Palaeocene boundary.     

Science and scientificity

A question about science We are now living in a scientific era, in which the theory and practice of science have penetrated into all aspects of society and science is often a hot topic. However, what on earth is science？ This question is largely neglected by many people, even researchers focusing on scientific studies may not have a very clear understanding of it.     

Science and nonsense

This article is a review of literature in developmental psychology concerned with children's thinking about their own bodies. There is an emphasis on ways in which children explain things that they know about their bodies. Very young children (younger than about 7 years of age) may have intuitive understanding of the distinction between the biological nature of the body and ways in which the mind controls and influences the body, but they sometimes explain processes that adults think of as biological in psychological ways. Older children acquire knowledge of internal organs and processes in the body, particularly ones concerned with the transformation of substances. However, they may understand these processes in ways different from that of a basic biological framework. The possibility that children have ideas about vital energies or forces is considered. Some implications for biology education are discussed.     

Science and Ideology

Abstract

Paul R. Gross and Norman Levitt. Higher Superstition: The Academic Left and Its Quarrels with Science. The Johns Hopkins University Press, 1994. 315 pages. $25.95 hardback.