Philosophical and epistemological debate in Italy within an ethical perspective of Earth sciences

During the recent "Geoitalia" national congress, the Italian scientific community tackled questions concerning the philosophy and sociology of Earth Sciences. The topics discussed and reported in this article were: the overall identity of E.S.; the validation procedures of data, theories and models; the power of attraction exerted by the philosophy of physics - exact science par excellence - with respect to E.S

A Hippocratic Oath for geologists?

We argue here that the introduction of an ethical code of conduct that follows the example of the Hippocratic Oath of physicians will help geologists to acquire binding awareness of their professional and social responsibilities. The ethical behavior and obligations of modern geologists involve, but are not limited to, the following issues: correct land/ environment use and management; respect of truth and science; and protection of the Earth systems, on both the local and global scales, and therefore, of our well-being. We believe that for geoligists, the explicit acceptance of an ethical code will help to promote: (i) an awareness of their social role, expertise and sense of belonging to a professional community; (ii) an understanding of the expectations of citizens and society; and (iii) cultural growth, with better use of research and implementation of scientific and professional skills. All this should enhance the public recognition of the social mission of geologists, which is essential for the well-being of society. Therefore, we suggest that like in the majority of medical schools, ethical training should be a part of the university curriculum for students in geology

Pinning and depinning of a classic quasi-one-dimensional Wigner crystal in the presence of a constriction

We studied the dynamics of a quasi-one-dimensional chain-like system of charged particles at low temperature, interacting through a screened Coulomb potential in the presence of a local constriction. The response of the system when an external electric field is applied was investigated. We performed Langevin molecular dynamics simulations for different values of the driving force and for different temperatures. We found that the friction together with the constriction pins the particles up to a critical value of the driving force. The system can depin \emph{elastically} or \emph{quasi-elastically} depending on the strength of the constriction. The elastic (quasi-elastic) depinning is characterized by a critical exponent $\beta\sim0.66$ ($\beta\sim0.95$). The dc conductivity is zero in the pinned regime, it has non-ohmic characteristics after the activation of the motion and then it is constant. Furthermore, the dependence of the conductivity with temperature and strength of the constriction was investigated in detail. We found interesting differences between the single and the multi-chain regimes as the temperature is increased.Comment: 18 pages, 16 figures, accepted for publication in PR

Variation in Flavonoids in Leaves, Stems and Flowers of White Clover Cultivars:

In the present study, the major flavonoids of white clover ( Trifolium repens L.) cv. Sonja were extracted, isolated and identified. The major flavonoids in leaves and stems were the four flavonol glycosides: kaempferol-3- O-{Xyl(1→2)-Gal} (kaempferol-Xyl-Gal), kaempferol-3- O-{Rha(1→6)-[Xyl(1→2)]-Gal} (kaempferol-Rha-Xyl-Gal), quercetin-3- O-{Xyl(1→2)-Gal} (quercetin-Xyl-Gal), and quercetin-3- O-{Rha(1→6)-[Xyl(1→2)]-Gal} (quercetin-Rha-Xyl-Gal). Quercetin-Rha-Xyl-Gal has never been reported before and kaempferol-Rha-Xyl-Gal has not previously been identified in clover aerial parts. Concentrations of those compounds, together with aglyconic flavonoids previously described in white clover, as well as their glycosides, were quantified in leaves/stems and flowers of four white clover cvs Rabani, Klondike, Ramona and Aran using tandem mass spectrometry. There were significant differences in flavonoid concentrations in the two plant parts, with the highest concentrations of most aglycones in flowers and the highest concentrations of most glycosides in leaves/stems. This distribution of compounds may indicate different ways of storage and/or different mechanisms of action of the compounds. The cultivars were selected for genetic diversity, which resulted in distinctly different amounts of flavonoids in the plants. Concentrations of 17 of 24 compounds varied significantly – for some compounds up to a factor of 10 – among cultivars. Total flavonoid concentrations in flowers did not vary greatly among cultivars, at 28.9–35.8 mmol/g dry material (DM). In contrast, in leaves/stems, the cvs Rabani and Klondike had lower concentrations of most flavonoids (total concentrations 10.0 and 12.7 mmol/gDM, respectively) compared to cvs Aran and Ramona (32.3 and 22.1 mmol/gDM, respectively). There is a potential for breeding/selection of cultivars with targeted concentrations of particular flavonoids

Direct interation of garcinol and related polyisoprenylated benzophenones of Garcinia cambogia fruits with the transcription factor STAT-1 as a likely mechanism of their inhibitory effect on cytokine signaling pathways.

Garcinol (1), a polyisoprenylated benzophenone occurring in Garcinia species, has been reported to exert anti-inflammatory activity in LPS-stimulated macrophages, through inhibition of NF-κB and/or JAK/STAT-1 activation. In order to provide deeper insight into its effects on the cytokine signaling pathway and to clarify the underlying molecular mechanisms, 1 was isolated from the fruits of Garcinia cambogia along with two other polyisoprenylated benzophenones, guttiferones K (2) and guttiferone M (3), differing from each other in their isoprenyl moieties and their positions on the benzophenone core. The affinities of 1-3 for the STAT-1 protein have been evaluated by surface plasmon resonance and molecular docking studies and resulted in KD values in the micromolar range. Consistent with the observed high affinity toward the STAT-1 protein, garcinol and guttiferones K and M were able to modulate cytokine signaling in different cultured cell lines, mainly by inhibiting STAT-1 nuclear transfer and DNA binding, as assessed by an electrophorectic mobility shift assay

Generic properties of a quasi-one dimensional classical Wigner crystal

We studied the structural, dynamical properties and melting of a quasi-one-dimensional system of charged particles, interacting through a screened Coulomb potential. The ground state energy was calculated and, depending on the density and the screening length, the system crystallizes in a number of chains. As a function of the density (or the confining potential), the ground state configurations and the structural transitions between them were analyzed both by analytical and Monte Carlo calculations. The system exhibits a rich phase diagram at zero temperature with continuous and discontinuous structural transitions. We calculated the normal modes of the Wigner crystal and the magneto-phonons when an external constant magnetic field $B$ is applied. At finite temperature the melting of the system was studied via Monte Carlo simulations using the $modified$ $Lindemann$ $criterion$ (MLC). The melting temperature as a function of the density was obtained for different screening parameters. Reentrant melting as a function of the density was found as well as evidence of directional dependent melting. The single chain regime exhibits anomalous melting temperatures according to the MLC and as a check we study the pair correlation function at different densities and different temperatures, formulating a different criterion. Possible connection with recent theoretical and experimental results are discussed and experiments are proposed.Comment: 13 pages text, 21 picture

Triterpene Saponins from the Aerial Parts of Trifolium medium L. var. sarosiense

Seven previously unreported triterpene glycosides (1−7) were isolated from methanol extract of the aerial parts of Trifolium medium var. sarosiense (zigzag clover). Their structures were established by the extensive use of 1D and 2D NMR experiments along with ESI-MS and HRMS analyses. Compounds 1−7 are oleanane derivatives characterized by the presence of a keto group at C-22 of an aglycone and a primary alcoholic function at C-24 and differing functions at C-30. Among these, compounds 1−3 and 6 showed a secondary alcoholic function at C-11, which is methoxylated in compounds 4 and 7. Compound 5 was shown to possess a known aglycone, wistariasapogenol A; however, it is described here for the first time as a saponin constituent of the Trifolium genus. Some aspects of taxonomic classification of zigzag clover are also discussed