A mathematical view of biological complexity

This essay is a trial on giving some mathematical ideas about the concept of biological complexity, trying to explore four different attributes considered to be essential to characterize a complex system in a biological context: decomposition, heterogeneous assembly, self-organization, and adequacy. It is a theoretical and speculative approach, opening some possibilities to further numerical and experimental work, illustrated by references to several researches that applied the concepts presented here. (C) 2008 Elsevier B.V. All rights reserved.

Measuring complexity in three-trophic level systems

This essay is a trial on measuring complexity in a three-trophic level system by using a convex function of the informational entropy. The complexity measure defined here is compatible with the fact that real complexity lies between ordered and disordered states. Applying this measure to the data collected for two three-trophic level systems some hints about their organization are obtained. (C) 2008 Elsevier B.V. All rights reserved.

Florestan Fernandes and Interpretations of Brazil

Essays that became known as ""interpretations of Brazil"" appeared mostly between the proclamation of the Republic in 1889 and the spurt in academic life in the 1930s and later. These essays sought an overall analysis of Brazil. However, as universities developed, works of this kind began to lose ground to monographs with more circumscribed aims. The sociologist Florestan Fernandes greatly influenced this development, but his last important work, A revolucao burguesa no Brasil (The Bourgeois Revolution in Brazil), written after the military coup of 1964, differs from his other works, as is indicated by its subtitle, ""an essay of sociological interpretation."" On the one hand lies the ""essay,"" on the other the ""sociological interpretation."" The former allows him to ""interpret Brazil,"" but he does so with the eyes of a sociologist. Establishing a dialogue between A revolucao burguesa no Brasil and other interpretations of Brazil such as those of Prado Junior, Vianna, Buarque, and Freyre reveals the significance of this distinction.

BIOMECHANICAL EVALUATION OF ORTHOPAEDIC CEMENT COMBINED WITH ANTIBIOTIC AND METHYLENE BLUE

Objective: Acrylic cement has been used for years on orthopaedic surgeries, especially on knee arthroplasties, deserving special attention when added to antibiotics (for treatment of deep bone infections) or stains (to facilitate its removal). The present study was conducted in order to evaluate potential mechanical differences between the orthopaedic cement itself and when this is added to antibiotic and/or stains. Methods: Surgical bone cement Simplex@P Stryker, vancomycin and methylene blue were used, and the mixtures were submitted to physical and mechanical tests according the ABNT NBR ISO 5833 rule. The parameters studied here were: time for mass formation, intrusion capability, resistance to compression, resistance to flexion and maximum temperature reached by the mixtures. Results: The evaluated mixtures were approved as to mass formation, maximum temperature, intrusion capability and resistance to compression. Only the one containing pure cement was approved on the flexion essay. Conclusion: The addition of vancomycin and/or methylene blue to Surgical Simplex@P Stryker bone cement reduces its resistance to flexion, being unacceptable by the ABNT NBR ISO 5833 rule.