Bullettin of the Gioenia Academy of Natural Sciences of Catania

Advantages and drawbacks of the digital revolution in scientific research publishing. Arkivoc: a virtuous example of platinum open access journal

2025-03-08T16:44:32+00:00

A radical change in scholarly communication occurred with the advent of internet which prompted on line digital publishing as Open Access (OA) and metrics evaluation of research. We here discuss the advantages and drawbacks of this open access revolution and, in this context, the merits of a platinum open access journal, Arkivoc, founded in 2000 with the support of a generous donation by professor Alan Roy Katritzky. This paper is a tribute to him for his vision and generosity to the advancement of free chemical publication to scientists.

Scientific Names and Authors of current Tribes in the red algal family Rhodomelaceae (Ceramiales, Rhodophyta): a nomenclatural analysis

2025-08-07T04:36:57+00:00

This paper deals with the correct citation of names of authors of Tribes formed from genus names currently assigned to the Rhodomelaceae. Unfortunately, nomenclatural problems and incorrect author citations have occurred for various Tribe names currently placed in the Rhodomelaceae. According to Díaz-Tapia & al. (2017: 920), the Rhodomelaceae is the largest family of red algae with over 1000 currently recognized species and over 140 currently recognized genera. A nomenclatural overview dealing with the scientific naming of taxa, the citation of authors of scientific names and a nomenclatural analysis of the taxonomic ranks utilized by some previous authors, is followed by a detailed account of the correct Tribe names, author citations and associated information. A glossary of nomenclatural terms and phrases used in this account is also included.

The importance of shape: Stereochemical curiosities

2025-08-07T04:43:37+00:00

The geometric shape of many molecules is responsable of their chemical and physical characteristics. Analysing the stereochemistry of isomeric molecules we report some curiosity about their different characteristics and how this is reflected on their use in technology and in biology. In particular we shall examine some geometrical isomers (cis-trans isometry), optical isomers (enatiomers), rotational isomers and molecules which can modify their shape by external stimulus. In this respect, the use of some molecular machinery are reported.

En-route formation of silica-undersaturated magmas through interaction at shallow crustal levels: insights from nephelinites of the Hyblean Plateau, Southern Italy

2025-08-12T03:47:00+00:00

Neogene to Quaternary volcanic rocks from the Hyblean area (Southeastern Sicily) mostly consist of basalts with both alkaline and tholeiitic affinity, erupted in most cases in submarine settings. Minor basanites and nephelinites also occur. Nephelinites mark the resuming of the eruptive activity in this area during Late Miocene, after a non-magmatic period of about 50 Ma, either in form of diatremes or lava flows. Hence, nephelinitic lavas were the final volcanic products on Early Pleistocene. This work is based on whole rock analyses from literature and original in situ investigations by SEM-EDS/WDS of juvenile clasts from tuff-breccia deposits related to diatremic eruptions and lava flow effusions, together with a new unique sampling of a Quaternary lava flow in the area of the San Demetrio quarries, with all samples coming from the northern part of the Hyblean Plateau. Texture of samples varies from subaphyric (especially in the diatremic facies) to highly porphyritic, containing olivine, Ti-rich augite and Ti-magnetite phenocrysts immersed in a groundmass of Ti-augite, nepheline, abundant apatite, Fe-Ti oxide micrograins, rare reacting orthopyroxene and micro-phenocrysts pertaining to minerals of the sodalite group. The groundmass is also characterized by scarce amounts of interstitial glass, often enriched in S, Cl and P, with either haüyne-like or feldspar-like compositions. In the latter case, acicular µm-sized plagioclases are also immersed in the glass. All samples display exceptional chemical heterogeneity, a feature even more emphasized among the residual glass compositions. It is also worth noting that the coexistence of nephelinites and alkali basalts occurs at the scale of the same outcrop, as in the case of the San Demetrio lava flow. The origin of Hyblean nephelinites has been previously related to the influence of metasomatic agents, represented by carbonatitic melts, acting into the mantle source. A new perspective has been provided here, implying that the final, extreme heterogenous compositions of these Hyblean ultramafic volcanic rocks can originate from ascending basaltic magmas that have assimilated variable amounts of phyllosilicates and evaporite-like salts.

Investigation of the charge symmetry of the nuclear interaction using quasi-free scattering

2025-01-12T14:48:25+00:00

The study of nuclear forces, in particular the interaction between nucleons in the spin singlet state \(^1S_0\), allows us to examine the concepts of charge independence and charge symmetry. This latter property implies that the interaction between two protons is identical to that between two neutrons, except for small effects due to the different mass and charge of the particles. These effects leave their fingerprints on the scattering lengths that characterize low-energy nucleon-nucleon interactions. Precise measurements of the neutron-proton (\(n\)-\(p\)), proton-proton (\(p\)-\(p\)), and neutron-neutron (\(n\)-\(n\)) \(s\)-wave scattering lengths are essential for understanding charge symmetry breaking and refining nuclear force models. \(^1S_0\) proton-proton (\(p\)-\(p\)) scattering length requires Coulomb effects to be theoretically removed; yet, the Coulomb-free \(p\)-\(p\) data strongly depends on various theoretical techniques to subtract the Coulomb contribution. In this study, Tumino et al. (2023) aimed at measuring the Coulomb-free \(p\)-\(p\) scattering length directly, namely, minimizing the model dependence uncertainty. It has been extracted from the \(p\)-\(p\) scattering cross section measured at center-of-mass energies below 1 MeV via the quasi-free \(p+d \to p+p+n\) reaction, applying the Trojan Horse Method. A Bayesian data-fitting approach employing the expression of the s-wave nucleon-nucleon scattering cross section yielded a \(p\)-\(p\) scattering length \(a_{pp} = -18.17^{+0.52}_{-0.58}|_{\mathrm{stat}} \pm 0.01|_{\mathrm{syst}} \, \mathrm{fm}\) and an effective range \(r_0 = 2.80 \pm 0.05_{\mathrm{stat}} \pm 0.001_{\mathrm{syst}} \, \mathrm{fm}\), to be compared with the values in the literature, \(a_{pp} = -17.3 \pm 0.4 \, \mathrm{fm}\) and \(r_0 = 2.85 \pm 0.04 \, \mathrm{fm}\) (Machleidt and Slaus, 2001). It is important to underscore that the Coulomb-free \(p\)-\(p\) scattering length in the literature is devoid of short-range physics, which should be incorporated for a meaningful comparison. Therefore, a model founded on universality principles was developed to interpret these findings. It incorporates the short-range interaction as a whole, including nuclear and residual electromagnetic effects, similar to how the s-wave phase shift \(\delta\) operates in describing low-energy nucleon-nucleon scattering data. The calculated scattering length including short-range physics, \(a_{pp} = -17.6 \pm 0.4 \, \mathrm{fm}\), is in very good agreement with the Trojan Horse data, while model dependence is negligible as, in the universality framework, results are almost insensitive to the details of the interaction. The comparison with the current accepted short-range \(a_{pp} \) and \( a_{nn}\) values suggests that differences in the masses of up and down quarks and their electromagnetic interactions have a smaller-than-expected impact within the context of charge symmetry breaking, while other contributions such as partial waves beyond \(^1S_0\), three-nucleon interactions and the difference between quark scalar densities in proton and neutrons may play a role, especially at higher energies.

Abstract of the lecture delivered at Palazzo Grimaldi in Modica on January 10, 2025, on the occasion of the ceremony for the award of the Grimaldi Prize 2024.