Viewing scenes of the history of chemistry through the opera glass

Artistic creation has always reflected the spirit of the moment and opera has not been an exception. There are several examples of operas which appeared at key moments of the development of science, portraying them. Additionally there are also operas that emerged after scientific events or the lifetime of the scientists they were inspired on. In what concerns chemistry, the first category could be exemplified by the apothecary operas (already discussed by the author in a previous paper of this journal) while the others could be illustrated by recent operas such as Dr. Atomic or Madame Curie. Continuing our endeavor of establishing relations between opera and chemistry, and considering that history of science plays an important role in the process of teaching and learning sciences, some milestones of the history of chemistry are here revisited through the opera glass. The operas analyzed have been grouped in the following categories: Operas of Fire and Metallurgy, Operas of the Philosophers of Antiquity, Operas of Alchemy, Operas of the Age of Enlightenment, Operas of the Revolutions and Operas of Entropy.Thanks are due to the Foundation for Science and Technology (FCT–Portugal) and FEDER (European Fund for Regional Development)-COMPETE/QREN/EU for financial support through the research unity PEst-C/QUI/UI686/2013.

Neuer Kopf, alte Ideen? : "Normalisierung" des Front National unter Marine Le Pen

In this article, it is investigated whether vibrational entropy (VE) is an important contribution to the free energy of globular proteins at ambient conditions. VE represents the major configurational-entropy contribution of these proteins. By definition, it is an average of the configurational entropies of the protein within single minima of the energy landscape, weighted by their occupation probabilities. Its large part originates from thermal motion of flexible torsion angles giving rise to the finite peak widths observed in torsion angle distributions. While VE may affect the equilibrium properties of proteins, it is usually neglected in numerical calculations as its consideration is difficult. Moreover, it is sometimes believed that all well-packed conformations of a globular protein have similar VE anyway. Here, we measure explicitly the VE for six different conformations from simulation data of a test protein. Estimates are obtained using the quasi-harmonic approximation for three coordinate sets, Cartesian, bond-angle-torsion (BAT), and a new set termed rotamer-degeneracy lifted BAT coordinates by us. The new set gives improved estimates as it overcomes a known shortcoming of the quasi-harmonic approximation caused by multiply populated rotamer states, and it may serve for VE estimation of macromolecules in a very general context. The obtained VE values depend considerably on the type of coordinates used. However, for all coordinate sets we find large entropy differences between the conformations, of the order of the overall stability of the protein. This result may have important implications on the choice of free energy expressions used in software for protein structure prediction, protein design, and NMR refinement

Redes Sociais e Comportamento Sexual: para uma visão relacional da sexualidade, do risco e da prevenção

Com base num inquérito representativo da população portuguesa entre 18 e 65 anos, realizado em 2007, este estudo investiga o impacto de fatores de rede social sobre os comportamentos sexuais dos indivíduos. Através da percepção normativa dos inquiridos sobre a moral sexual dos seus amigos e familiares e de indicadores relativos à caracterização da rede de confidência sexual, tais como o número, a identidade, o gênero, a idade e o comportamento dos confidentes em matéria de sexualidade e prevenção face ao risco de infecção por DSTs, obtivemos um retrato multidimensional das redes sociais dos indivíduos. A realização de análises de regressão linear e logística permitiu avaliar o impacto preditivo da rede sobre o número de parceiros sexuais, as relações sexuais ocasionais e o uso do preservativo. Os dados mostram que os fatores de rede são importantes para explicar o comportamento sexual dos indivíduos. Redes constituídas por amigos e mais liberais em termos de moral sexual tendem a influenciar o comportamento sexual, levando a um maior experimentalismo, sobretudo no caso das mulheres. Por outro lado, a homologia entre o comportamento sexual dos confidentes e o dos inquiridos é relevante para explicar o recurso ao preservativo nas relações sexuais ocasionais, especialmente no caso dos homens. Tanto numa perspectiva relacional da sexualidade como numa óptica epidemiológica, a análise das redes sociais dos indivíduos constitui um aspecto importante para a compreensão e explicação da variedade de experiências sexuais, mais restritas ou mais plurais, e para os riscos de infecção que daí podem advir

The Consensus from the Mycobacterium avium ssp. paratuberculosis (MAP) Conference 2017.

On March 24 and 25, 2017 researchers and clinicians from around the world met at Temple University in Philadelphia to discuss the current knowledge of Mycobacterium avium ssp. paratuberculosis (MAP) and its relationship to human disease. The conference was held because of shared concern that MAP is a zoonotic bacterium that poses a threat not only to animal health but also human health. In order to further study this problem, the conferees discussed ways to improve MAP diagnostic tests and discussed potential future anti-MAP clinical trials. The conference proceedings may be viewed on the www.Humanpara.org website. A summary of the salient work in this field is followed by recommendations from a majority of the conferees

Classical Morphology of Plants as an Elementary Instance of Classical Invariant Theory

It has long been known that structural chemistry shows an intriguing correspondence with Classical Invariant Theory (CIT). Under this view, an algebraic binary form of the degree n corresponds to a chemical atom with valence n and each physical molecule or ion has an invariant-theoretic counterpart. This theory was developed using the Aronhold symbolical approach and the symbolical processes of convolution/transvection in CIT was characterized as a potential “accurate morphological method”. However, CIT has not been applied to the formal morphology of living organisms. Based on the morphological interpretation of binary form, as well as the process of convolution/transvection, the First and Second Fundamental Theorems of CIT and the Nullforms of CIT, we show how CIT can be applied to the structure of plants, especially when conceptualized as a series of plant metamers (phytomers). We also show that the weight of the covariant/invariant that describes a morphological structure is a criterion of simplicity and, therefore, we argue that this allows us to formulate a parsimonious method of formal morphology. We demonstrate that the “theory of axilar bud” is the simplest treatment of the grass seedling/embryo. Our interpretations also represent Troll's bauplan of the angiosperms, the principle of variable proportions, morphological misfits, the basic types of stem segmentation, and Goethe's principle of metamorphosis in terms of CIT. Binary forms of different degrees might describe any repeated module of plant organisms. As bacteria, invertebrates, and higher vertebrates are all generally shared a metameric morphology, wider implications of the proposed symmetry between CIT and formal morphology of plants are apparent