Dynamical changes of the polar cap potential structure: an information theory approach

Some features, such as vortex structures often observed through a wide spread of spatial scales, suggest that ionospheric convection is turbulent and complex in nature. Here, applying concepts from information theory and complex system physics, we firstly evaluate a pseudo Shannon entropy, <i>H</i>, associated with the polar cap potential obtained from the Super Dual Auroral Radar Network (SuperDARN) and, then, estimate the degree of disorder and the degree of complexity of ionospheric convection under different Interplanetary Magnetic Field (IMF) conditions. The aforementioned quantities are computed starting from time series of the coefficients of the 4th order spherical harmonics expansion of the polar cap potential for three periods, characterised by: (i) steady IMF <i>B<sub>z</sub></i> > 0, (ii) steady IMF <i>B<sub>z</sub></i> < 0 and (iii) a double rotation from negative to positive and then positive to negative <i>B<sub>z</sub></i>. A neat dynamical topological transition is observed when the IMF <i>B<sub>z</sub></i> turns from negative to positive and vice versa, pointing toward the possible occurrence of an order/disorder phase transition, which is the counterpart of the large scale convection rearrangement and of the increase of the global coherence. This result has been confirmed by applying the same analysis to a larger data base of about twenty days of SuperDARN data, allowing to investigate the role of IMF <i>B<sub>y</sub></i> too

Dynamical changes of the polar cap potential structure: an information theory approach

Abstract. Some features, such as vortex structures often observed through a wide spread of spatial scales, suggest that ionospheric convection is turbulent and complex in nature. Here, applying concepts from information theory and complex system physics, we firstly evaluate a pseudo Shannon entropy, H, associated with the polar cap potential obtained from the Super Dual Auroral Radar Network (SuperDARN) and, then, estimate the degree of disorder and the degree of complexity of ionospheric convection under different Interplanetary Magnetic Field (IMF) conditions. The aforementioned quantities are computed starting from time series of the coefficients of the 4th order spherical harmonics expansion of the polar cap potential for three periods, characterised by: (i) steady IMF Bz > 0, (ii) steady IMF Bz < 0 and (iii) a double rotation from negative to positive and then positive to negative Bz. A neat dynamical topological transition is observed when the IMF Bz turns from negative to positive and vice versa, pointing toward the possible occurrence of an order/disorder phase transition, which is the counterpart of the large scale convection rearrangement and of the increase of the global coherence. This result has been confirmed by applying the same analysis to a larger data base of about twenty days of SuperDARN data, allowing to investigate the role of IMF By too

FDA-Approved Fluorinated Heterocyclic Drugs from 2016 to 2022

The inclusion of fluorine atoms or heterocyclic moiety into drug structures represents a recurrent motif in medicinal chemistry. The combination of these two features is constantly appearing in new molecular entities with various biological activities. This is demonstrated by the increasing number of newly synthesized fluorinated heterocyclic compounds among the Food and Drug Administration FDA-approved drugs. In this review, the biological activity, as well as the synthetic aspects, of 33 recently FDA-approved fluorinated heterocyclic drugs from 2016 to 2022 are highlighted

Different responses of northern and southern high latitude ionospheric convection to IMF rotations: a case study based on SuperDARN observations

Abstract. We use SuperDARN data to study high-latitude ionospheric convection over a three hour period (starting at 22:00 UT on 2 January 2003), during which the Interplanetary Magnetic Field (IMF) flipped between two states, one with By&amp;gt;&amp;gt;|Bz| and one with Bz&amp;gt;0, both with negative Bx. We find, as expected from previous works, that day side ionospheric convection is controlled by the IMF in both hemispheres. For strongly northward IMF, we observed signatures of two reverse cells, both in the Northern Hemisphere (NH) and in the Southern Hemisphere (SH), due to lobe reconnection. On one occasion, we also observed in the NH two viscous cells at the sides of the reverse cell pair. For duskward IMF, we observed in the NH a large dusk clockwise cell, accompanied by a smaller dawn cell, and the signature of a corresponding pattern in the SH. On two occasions, a three cell pattern, composed of a large clockwise cell and two viscous cells, was observed in the NH. As regards the timings of the NH and SH convection reconfigurations, we find that the convection reconfiguration from a positive Bz dominated to a positive By dominated pattern occurred almost simultaneously (i.e. within a few minutes) in the two hemispheres. On the contrary, the reconfiguration from a By dominated to a northward IMF pattern started in the NH 8–13 min earlier than in the SH. We suggest that part of such a delay can be due to the following mechanism: as IMF Bx&amp;lt;0, the northward-tailward magnetosheath magnetic field reconnects with the magnetospheric field first tailward of the northern cusp and later on tailward of the southern cusp, due to the IMF draping around the magnetopause.</p

Synthesis and Antibacterial Activity of Mono- and Bi-Cationic Pyridinium 1,2,4-Oxadiazoles and Triazoles

One of the main causes of mortality in humans continues to be infectious diseases. Scientists are searching for new alternatives due to the fast increase in resistance of some harmful bacteria to the frontline antibiotics. To effectively treat pathogenic infections, it is crucial to design antibiotics that can prevent the development of pathogenic resistance. For this purpose, a set of 39 quaternary pyridinium and bis-pyridinium salts with different lengths of side alkyl or fluorinated chains, heterocyclic spacers, and counter ions were tested on diverse reference bacterial ATCC (American Type Culture Collection) strains, such as S. aureus and E. coli. Subsequently, 6 out of the 39 pyridinium salts showing relevant MIC (Minimum Inhibitory Concentration) values were tested on clinically isolated, resistant strains of S. aureus, S. epidermids, S. haemolyticus, K. pneumoniae, A. baumannii, and P. aeruginosa. Additional tests have been performed to assess if the minimum concentration detected through MIC assay may limit the growth of biofilms

Multi-phosphorylation of the intrinsically disordered unique domain of c-Src studied by in-cell and real-time NMR

Intrinsically disordered regions (IDRs) are preferred sites for post-translational modifications essential for regulating protein function. The enhanced local mobility of IDRs facilitates their observation by NMR spectroscopy in vivo. Phosphorylation events can occur at multiple sites and respond dynamically to changes in kinase-phosphatase networks. Here we used real-time NMR spectroscopy to study the effect of kinases and phosphatases present in Xenopus oocytes and egg extracts on the phosphorylation state of the 'unique domain' of c-Src. We followed the phosphorylation of S17 in oocytes, and of S17, S69, and S75 in egg extracts by NMR spectroscopy, MS, and western blotting. Addition of specific kinase inhibitors showed that S75 and S69 are phosphorylated by CDKs (cyclin-dependent kinases) differently from Cdk1. Moreover, although PKA (cAMP-dependent protein kinase) can phosphorylate S17 in vitro, this was not the major S17 kinase in egg extracts. Changes in PKA activity affected the phosphorylation levels of CDK-dependent sites, thus suggesting indirect effects of kinase-phosphatase networks. This study provides a proof-of-concept of the use of real-time in vivo NMR spectroscopy to characterize kinase/phosphatase effects on intrinsically disordered regulatory domains

Materiais didáticos no ensino e aprendizagem da matemática

O relatório final de estágio apresenta-se no âmbito do Mestrado em Educação Pré-Escolar e Ensino do 1.º Ciclo do Ensino Básico. Este inclui uma reflexão crítica relativamente às unidades curriculares de Prática de Ensino Supervisionada (II e III), em contexto de estágio, no 1.º Ciclo do Ensino Básico e na Educação Pré-Escolar. O relatório contempla ainda uma investigação cuja temática se centra na área da Matemática. Para a realização da primeira parte do relatório, foram utilizados diversos materiais construídos e implementados ao longo das PES II e III, bem como autores de referência, de forma a fundamentar o texto. Relativamente à segunda parte do relatório final de estágio foi realizada uma investigação de caráter qualitativo, que teve como principal objetivo perceber de que forma a utilização de materiais didáticos, em aulas do 1.º Ciclo do Ensino Básico, influencia a aprendizagem da Matemática, num tópico muito particular: números racionais. Desta forma, foi realizado um teste diagnóstico de forma a perceber o conteúdo em que os alunos sentiam mais dificuldades. Posteriormente, foram desenvolvidas três tarefas diferentes, utilizando materiais didáticos distintos e, foi ainda realizada uma entrevista semiestruturada aos três participantes do estudo. A análise dos dados recolhidos permitiu concluir, com alguma segurança, que a utilização de materiais didáticos, em conteúdos matemáticos, é benéfica para os alunos, pois revelam maior envolvimento nas tarefas propostas e uma melhor compreensão dos conteúdos abordados.The final apprenticeship report is related to the scope of the Masters Degree of Pre-schooling and Teaching the 1st Cycle of Basic School. It includes a critical reflection in relation to the curricular units of Supervised Teaching Practice (II and III), in the context of apprenticeship, in the 1st Cycle of Basic School and in Pre-school Education. The report also contemplates research whose theme concentrates on the fields of mathematics. For the first part of the report several different materials were used, which had been built and implemented along STP II and III, as well as authors of reference, so as to support the text. In relation to the second part of the apprenticeship final report, a qualitative research was carried out, which main purpose was to understand to which extent the use of didactic materials in the 1st cycle of Basic School classes influences the learning of mathematics, in a very particular topic: rational numbers. This way, a diagnosis was performed for a better understanding of the contents in which learners feel the most difficulties. Later on three tasks were developed, by using different didactic materials, and a semi-structured interview was held to the three participants in the study. The analysis of the collected data allowed to conclude, with some certainty, that the use of didactic materials in mathematical contents is beneficial for learners, because they reveal a greater involvement in the proposed tasks and a better understanding of the addressed contents