Confronto tra Inquiry-based Science Education ed insegnamento tradizionale delle Scienze in alcune scuole superiori italiane

This study aims to evaluate if inquiry-based science education (IBSE) at the high school level allows the achievement of better learning objectives with respect to conventional science education (CSE). The findings would help to understand if, how, and why IBSE can be used as a successful teaching approach. The study included four high schools with different specialties, eight experienced science teachers and approximately 350 students, attending sixteen classes. Two biochemistry topics were taught by the same teacher in two classes. A two stage quasi experimental, crossover design was adopted. The primary outcome compared the difference in the average pre-teaching and post-teaching test-scores, using a 3-multilevel analysis. On average, the outcome in terms of scores significantly improved by 4% with IBSE with respect to the CSE approach, demonstrating differences among the school specialties. In conclusion, our study indicates that IBSE is significantly more effective in enhancing skills.Questo studio mira a valutare se l’approccio “Inquiry-based science education” (IBSE) consenta il raggiungimento di obiettivi di apprendimento, a livello di scuola superiore, in modo più efficacerispetto all’educazione scientifica convenzionale (CSE). I risultati possono aiutare a capire se, come e perché IBSE può essere utilizzato come approccio didattico di successo. Lo studio ha inclusoquattro scuole superiori con diversi indirizzi, otto insegnanti di scienze con esperienza e circa 350 studenti, suddivisi in sedici classi. Due tematiche di biochimica sono state insegnate dallo stesso docente in due classi parallele. È stato adottato un disegno quasi sperimentale, crossover, a due fasi. Obiettivo primario è stato confrontare la differenza nei punteggi medi nei test prima e dopo le attività, utilizzando un’analisi gerarchica a 3 livelli. In media, il risultato in termini di punteggi è migliorato significativamente del 4% con IBSE rispetto all’approccio CSE, dimostrando differenze tra gli indirizzi scolastici. In conclusione, il nostro studio indica che IBSE è significativamente più efficace nel migliorare le competenze

A method to search for long duration gravitational wave transients from isolated neutron stars using the generalized FrequencyHough

We describe a method to detect gravitational waves lasting $O(hours-days)$ emitted by young, isolated neutron stars, such as those that could form after a supernova or a binary neutron star merger, using advanced LIGO/Virgo data. The method is based on a generalization of the FrequencyHough (FH), a pipeline that performs hierarchical searches for continuous gravitational waves by mapping points in the time/frequency plane of the detector to lines in the frequency/spindown plane of the source. We show that signals whose spindowns are related to their frequencies by a power law can be transformed to coordinates where the behavior of these signals is always linear, and can therefore be searched for by the FH. We estimate the sensitivity of our search across different braking indices, and describe the portion of the parameter space we could explore in a search using varying fast Fourier Transform (FFT) lengths.Comment: 15 figure

Spermatozoa capture HIV-1 through heparan sulfate and efficiently transmit the virus to dendritic cells

Semen is the main vector for HIV-1 dissemination worldwide. It contains three major sources of infectious virus: free virions, infected leukocytes, and spermatozoa-associated virions. We focused on the interaction of HIV-1 with human spermatozoa and dendritic cells (DCs). We report that heparan sulfate is expressed in spermatozoa and plays an important role in the capture of HIV-1. Spermatozoa-attached virus is efficiently transmitted to DCs, macrophages, and T cells. Interaction of spermatozoa with DCs not only leads to the transmission of HIV-1 and the internalization of the spermatozoa but also results in the phenotypic maturation of DCs and the production of IL-10 but not IL-12p70. At low values of extracellular pH (∼6.5 pH units), similar to those found in the vaginal mucosa after sexual intercourse, the binding of HIV-1 to the spermatozoa and the consequent transmission of HIV-1 to DCs were strongly enhanced. Our observations support the notion that far from being a passive carrier, spermatozoa acting in concert with DCs might affect the early course of sexual transmission of HIV-1 infection

Impact of signal clusters in wide-band searches for continuous gravitational waves

International audienceIn this paper we present a study of some relevant steps of the hierarchical frequency-Hough (FH) pipeline, used within the LIGO and Virgo Collaborations for wide-parameter space searches of continuous gravitational waves (CWs) emitted, for instance, by spinning neutron stars (NSs). Because of their weak expected amplitudes, CWs have not been still detected so far. These steps, namely the spectral estimation, the peakmap construction and the procedure to select candidates in the FH plane, are critical as they contribute to determine the final search sensitivity. Here, we are interested in investigating their behavior in the (presently quite) extreme case of signal clusters, due to many and strong CW sources, emitting gravitational waves (GWs) within a small (i.e., <1  Hz wide) frequency range. This could happen for some kinds of CW sources detectable by next generation detectors, like LISA, Einstein Telescope, and Cosmic Explorer. Moreover, this possibility has been recently raised even for current Earth-based detectors, in some scenarios of CW emission from ultralight boson clouds around stellar mass black holes (BHs). We quantitatively evaluate the robustness of the FH analysis procedure, designed to minimize the loss of single CW signals, under the unusual situation of signal clusters. Results depend mainly on how strong in amplitude and dense in frequency the signals are, and on the range of frequency they cover. We show that indeed a small sensitivity loss may happen in presence of a very high mean signal density affecting a frequency range of the order of one Hertz, while when the signal cluster covers a frequency range of one tenth of Hertz, or less, we may actually have a sensitivity gain. Overall, we demonstrate the FH to be robust even in presence of moderate-to-large signal clusters

Direct constraints on ultra-light boson mass from searches for continuous gravitational waves

International audience\textit{Superradiance} can trigger the formation of an ultra-light boson cloud around a spinning black hole. Once formed, the boson cloud is expected to emit a nearly periodic, long-duration, gravitational-wave signal. For boson masses in the range $(10^{-13}-10^{-11})$ eV, and stellar mass black holes, such signals are potentially detectable by gravitational wave detectors, like Advanced LIGO and Virgo. In this {\it Letter} we present full band upper limits for a generic all-sky search for periodic gravitational waves in LIGO O2 data, and use them to derive - for the first time - direct constraints on the ultra-light scalar boson field mass

How effective is machine learning to detect long transient gravitational waves from neutron stars in a real search?

International audienceWe present a comprehensive study of the effectiveness of convolution neural networks (CNNs) to detect long-duration transient gravitational-wave signals lasting O(hours–days) from isolated neutron stars. We determine that CNNs are robust towards signal morphologies that differ from the training set, and they do not require many training injections/data to guarantee good detection efficiency and low false alarm probability. In fact, we only need to train one CNN on signal/noise maps in a single 150 Hz band; afterwards, the CNN can distinguish signals/noise well in any band, though with different efficiencies and false alarm probabilities due to the nonstationary noise in LIGO/Virgo. We demonstrate that we can control the false alarm probability for the CNNs by selecting the optimal threshold on the outputs of the CNN, which appears to be frequency dependent. Finally we compare the detection efficiencies of the networks to a well-established algorithm, the Generalized FrequencyHough (GFH), which maps curves in the time/frequency plane to lines in a plane that relates to the initial frequency/spin-down of the source. The networks have similar sensitivities to the GFH but are orders of magnitude faster to run and can detect signals to which the GFH is blind. Using the results of our analysis, we propose strategies to apply CNNs to a real search using LIGO/Virgo data to overcome the obstacles that we would encounter, such as a finite amount of training data. We then use our networks and strategies to run a real search for a remnant of GW170817, making this the first time ever that a machine learning method has been applied to search for a gravitational-wave signal from an isolated neutron star

Determination of the neutral to charged current cross section ratio for neutrino interactions on protons

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Strange baryon production in p-Pb collisions at 158 GeV/c: a comparison with VENUS model

Lambda, Xi and Omega yields measured by the WA97 experiment at central rapidity in p-Pb interactions at 158 GeV/c are compared to those predicted by VENUS 4.12. The VENUS model, although in reasonable agreement with the Lambda and the negative particle data, fails to reproduce the data on multistrange baryons and anti-baryons