In classe con Pile e Lampadine

Per insegnare le scienze fisiche con un approccio laboratoriale, gli insegnanti necessitano di un sostegno per sviluppare l’epistemologia disciplinare necessaria. Questo argomento di solito non viene trattato nella formazione di base e perciò i corsi di formazione in servizio si sono mostrati una valida alternativa. Qui ci si riferisce a un corso per insegnanti della scuola primaria e della secondaria di primo grado con il quale si volevano focalizzare i concetti della disciplina e le strategie di insegnamento che meglio si prestano ad un insegnamento efficace sui circuiti elettrici. La premessa era che è importante capire come e quando gli studenti applicano le conoscenze che hanno già di quell’argomento prima di averne sentito parlare a scuola. In occasione del corso di formazione sono state anche condotte delle osservazioni su due gruppi di studenti, 20 di quinta elementare e 18 di prima media.Questo numero della rivista è stato pubblicato con il contributo della Fondazione CRTriest

Magnetic island evolution under the action of electron cyclotron current drive

The magnetic island evolution under the action of an externally current generated by electron cyclotron (ECCD) wave beams is studied using a reduced resistive magnetohydrodynamics (RRMHD) plasma model. We found interesting and somewhat unexpected features of the actual nonlinear 2-D evolution of the magnetic perturbation depending on the injection time of the radio frequency control. In particular in the linear phase of the magnetic island growth we observe that the complete annihilation of the island width is followed by a spatial phase shift of the island, referred as «flip»instability. On the other hand, a current drive deposition in the Rutherford regime can be accompained by the occurrence of a Kelvin-Helmholtz type shear flow instability, responsible for the onset of a plasma turbulent behavio

Descrivere e dare valore all’apprendimento: Proposte ed esperienze nell’ambito scientifico-matematico

This article presents some thoughts concerning the competence “Analyse and interpret data and draw appropriate conclusions” and to the way STEM could contribute to such competence. The fieldwork of reference is that of an Italian Lower Secondary School. Investigative questions bear on the way the ability to interpret data and information is developed, the way such ability is used to draw conclusions, and the nature of the processes enacted by students in this sense. Furthermore, during the design of teaching activities, it emerged how important it is to identify links and shared processes between different STEM subjects, as well as the need to adopt appropriate instruments to observe and assess competence.Questo articolo presenta alcune riflessioni relative alla competenza “interpretare dati e informazioni per trarre conclusioni” e ai contributi che le discipline matematico-scientifiche possono offrire anche facendo riferimento ad esperienze realizzate in classi di Scuola Secondaria di I grado. Le domande che ci siamo poste riguardano le modalità di sviluppo delle capacità di interpretazione di dati e informazioni, dell’utilizzo di queste capacità per trarre conclusioni, la natura dei processi messi in atto dagli studenti. In fase di progettazione delle attività didattiche, è emersa anche l’importanza di individuare i collegamenti tra le diverse discipline scientifiche e i processi comuni e la necessità di adottare e utilizzare strumenti per osservare e valutare la competenza

Il curricolo verticale nella scuola del primo ciclo. Analisi, percorsi, strumenti

Un Istituto comprensivo è composto da tre ordini di scuola (dell'infanzia, primaria e secondaria di primo grado) con caratteristiche molto diverse, talvolta difficili da raccordare. Ciò nonostante, il curricolo d’Istituto (o verticale) va costruito insieme, con l'apporto di tutti gli insegnanti. Su quali basi? Il gruppo Università-Scuola del Laboratorio RED (Ricerca Educativa e Didattica) dell’Università Ca’ Foscari di Venezia, ha studiato e sperimentato, nelle pratiche formative, modelli aperti di progettazione del curricolo verticale per competenze, come proposto dalle Indicazioni nazionali, centrato sui nodi concettuali formativi, ovvero sui processi che sovrintendono agli apprendimenti nelle interconnessioni tra i multiformi potenziali formativi degli allievi e la ricchezza dei processi di conoscenza nei diversi ambiti disciplinari. Questo volume testimonia le analisi e i percorsi di ricerca-forma-azione nelle scuole, con gli insegnanti sperimentatori in classe

Basaltic asteroids observed with ESO/XShooter

We present new spectroscopic observations of 17 putative basaltic asteroids, in the 0.3-2.5 micron spectral band, with the ESO/XShooter facility. The observed spectral range encompasses the two pyroxene bands centred at 0.9 and 2.0 micron, typical of the basaltic asteroids. The data allowed to taxonomically classify the observed asteroids, and in some cases to confirm their basaltic nature

Genetic analysis of a PER-2-producing Shewanella sp. strain harbouring a variety of mobile genetic elements and antibiotic resistance determinants

The objective of this study was to investigate the molecular mechanisms explaining the multidrug-resistant (MDR) phenotype found in a novel clinical Shewanella sp. strain (Shew256) recovered from a diabetic patient. Whole-genome shotgun sequencing was performed using Illumina MiSeq-I and Nextera XT DNA library. De novo assembly was performed with SPAdes. RAST Server was used to predict the open-reading frames and the predictions were confirmed using BLAST. Further genomic analysis was carried out using average nucleotide identity (ANI), ACT (Artemis), OrthoMCL, ARG-ANNOT, ISfinder, PHAST, tRNAscan-SE, plasmidSPAdes, PlasmidFinder and MAUVE. PCR and plasmid extraction were also performed. Genomic analysis revealed a total of 456 predicted genes unique to Shew256 compared with other Shewanella genomes. Moreover, the presence of different resistance genes, including blaPER-2, was found. A complex class 1 integron containing the ISCR1 gene, disrupted by two putative transposase genes, was identified. Furthermore, other resistance genes, a transposon containing aph(3′), insertion sequences, phages and non-coding RNAs were also found. In conclusion, evidence of acquisition of resistance genes and mobile elements that could explain the MDR phenotype were observed. This Shewanella sp. represents a prime example of how antibiotic resistance determinants can be acquired by uncommon pathogens.Fil: Almuzara, Marisa. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Montaña, Sabrina Daiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Lazzaro, Terese. Universidad de la República; UruguayFil: Uong, Sylvia. Universidad de la República; UruguayFil: Parmeciano Di Noto, Gisela Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Traglia, German Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Bakai, Romina. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Centron, Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Iriarte Odini, Andrés. Universidad de la República; UruguayFil: Quiroga, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Ramirez, Maria Soledad. Universidad de la República; Uruguay. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

(523599) 2003 RM : The Asteroid that Wanted to be a Comet

We report a statistically significant detection of nongravitational acceleration on the subkilometer near-Earth asteroid (523599) 2003 RM. Due to its orbit, 2003 RM experiences favorable observing apparitions every 5 yr. Thus, since its discovery, 2003 RM has been extensively tracked with ground-based optical facilities in 2003, 2008, 2013, and 2018. We find that the observed plane-of-sky positions cannot be explained with a purely gravity-driven trajectory. Including a transverse nongravitational acceleration allows us to match all observational data, but its magnitude is inconsistent with perturbations typical of asteroids such as the Yarkovsky effect or solar radiation pressure. After ruling out that the orbital deviations are due to a close approach or collision with another asteroid, we hypothesize that this anomalous acceleration is caused by unseen cometary outgassing. A detailed search for evidence of cometary activity with archival and deep observations from the Panoramic Survey Telescope and Rapid Response System and the Very Large Telescope does not reveal any detectable dust production. However, the best-fitting H2O sublimation model allows for brightening due to activity consistent with the scatter of the data. We estimate the production rate required for H2O outgassing to power the acceleration and find that, assuming a diameter of 300 m, 2003 RM would require Q(H2O) similar to 10(23) molec s(-1) at perihelion. We investigate the recent dynamical history of 2003 RM and find that the object most likely originated in the mid-to-outer main belt (similar to 86% probability) as opposed to from the Jupiter-family comet region (similar to 11% probability). Further observations, especially in the infrared, could shed light on the nature of this anomalous acceleration.Peer reviewe

Lipid structural information from a single equine embryo by MALDI-MS

O objetivo deste trabalho foi relatar o potencial da técnica de MALDI-MS para caracterizar espécies de lipídios presentes em um único embrião equino e estudar algumas estruturas lipídicas detectadas por dissociação induzida por colisão (CID). No espectro de modo íon positivo, pudemos observar espécies, principalmente, protonadas e sodiadas de esfingomielinas (SM), fosfatidileolinas (PC) e triacilgliceróis (TAG). No modo negativo, observamos fosfatidiletanolaminas (PE) e fosfatidilinositos (PI). Espectros de íons de lípidos com maior intensidade foram utilizados para demonstrar o potencial da informação estrutural por MALDI-MS/MS. O espectro no modo positivo de m/z (massa sobre carga) 760,6 (atribuída como PC34:1) apresentou características de fragmentos PC de m/z 184,1 (denominada cabeça polar de colina), além de perda neutral (NL) de m/z 183 (fosforilcolina). Para o íon de m/z 766,6 (atribuída como PE38:5), observou-se a NL de 140, característica do PE. Para o íon de m/z 808,7 (38,5 atribuído como PC), além do fragmento m/z 184,1 na NL de 183, foi possível observar a perda de trimetilamina (íon de m/z 749,6) e o ciclofosfano (íon de m/z 147,0). Finalmente, para o modo de íon negativo, foram isolados e fragmentados o íon de m/z 863,6 que foi atribuído como PI36:1, devido à presença de m/z 153 (fosfato de glicerol – H2O-H ), 223 (inositol fosfo - 2H2O-H) , 241 (fosfoinositol – H2O-H), 281 (ácido oleico) e 581,3 (lisofosfoinositol – H2O+H). Concluímos que a MALDI - MS permite a detecção de uma ampla gama de espécies de PC, SM, PE, PI e TAG lipídicas, bem como a caracterização rápida e confiante de estruturas lipídicas a partir de um único embrião equino.The aim of this work was to report the potential of MALDI-MS for the characterization of lipid species present in a single equine embryo, and to study some lipid structures detected by collision induced dissociation (CID) experiments. In the positive ion mode spectrum, we could observe mostly protonated and sodiated species of sphingomyelins (SM), phosphatidylcholines (PC) and triacylglycerols (TAG). In the negative ion mode, we observed phosphatidylethanolamines (PE) and phosphatidylinositols (PI). MS/MS spectrum of most intense lipid ions was performed to show MALDI-MS/MS structural information potential. MS/MS spectrum in the positive mode of m/z 760.6 (attributed as PC34:1) depicted characteristic PC fragments of m/z 184.1 (choline polar head), and the neutral loss (NL) of 183 (phosphorylcholine). For the ion of m/z 766.6 (attributed as PE 38:5), we observed the NL of 140, characteristic of PE. For the ion of m/z 808.7 (attributed as PC 38.5), besides the fragment at m/z 184.1 at the NL of 183, it was possible to observe the loss of trimethylamine (ion of m/z 749.6), and the cyclophosphane (ion of m/z 147.0). Finally, for the negative ion mode, we isolated and fragmented the ion at m/z 863.6, which was attributed as PI 36:1 due to the presence of m/z 153 (glycerol phosphate – H2O-H), 223 (phospho inositol – 2H2O-H), 241 (phospho inositol – H2O-H), 281 (oleic acid), and 581.3 (lysophosphoinositol – H2O-H). We conclude that MALDI-MS allowed the detection of a broad range of PC, SM, PE, PI and TAG lipid species, as well as a fast and confident characterization of lipid structures from a single equine embryo.