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The paper focuses on the issues of merit, explored in its complex polysemy, meritocracy, and skills, placing them in relation to those of–educational, social, economic, cultural–poverty and social disadvantage, which afflict, with considerable aggravation especially in the era of Sars-Cov-2 pandemic, even Italy. The essay consists of three paragraphs. In the first two, a reference framework is outlined, on the one hand relating to the polysemic concepts of merit, and meritocracy; on the other, to the situation of poverty and social inequalities in Italy. The third paragraph, which represents the heart of the paper, is linked to the abovementioned frameworks: it highlights the key role that a widespread, accessible, and high-quality Early Childhood Education and Care (ECEC) play, both in supporting children's development, both promoting a democratic and inclusive society; a society characterized by effective \"merit dynamics\", open to all, so as to promote skills development and, above all, social ascent and redemption. Keywords. Merit - Meritocracy - Skills - Social disadvantage - Social redemption - Early Childhood Education and Care (ECEC)

High-mass star formation theories make distinct predictions on the properties of the prestellar seeds of high-mass stars. Observations of the early stages of high-mass star formation can provide crucial constraints, but they are challenging and scarce. We investigate the properties of the prestellar core population embedded in the high-mass clump AGAL014.492-00.139, and we study the kinematics at the clump and clump-to-core scales. We have analyzed an extensive data set acquired with the Atacama Large Millimeter/submillimeter Array interferometer. Applying a dendrogram analysis to the Band 7 o‐H2D+ data, we identified 22 cores. We fitted their average spectra in local thermodinamic equilibrium conditions, and we analyzed their continuum emission at 0.8 mm. The cores have transonic to mildly supersonic turbulence levels and appear to be mostly low-mass, with Mcore<30M⊙ . Furthermore, we have analyzed Band 3 observations of the N2H+ (1–0) transition, which traces the large-scale gas kinematics. Using a friend-of-friend algorithm, we identify four main velocity coherent structures, all of which are associated with prestellar and protostellar cores. One of them presents a filament-like structure, and our observations could be consistent with mass accretion toward one of the protostars. In this case, we estimate a mass accretion rate of Ṁacc≈2×10−4M⊙yr−1 . Our results support a clump-fed accretion scenario in the target source. The cores in the prestellar stage are essentially low-mass, and they appear to be subvirial and gravitationally bound, unless further support is available, for instance, due to magnetic fields.

Dust coagulation in protoplanetary disks is not straightforward and is subject to several slowdown mechanisms, such as bouncing, fragmentation, and radial drift to the star. Furthermore, dust grains in UV-shielded disk regions are negatively charged due to collisions with the surrounding electrons and ions, which leads to their electrostatic repulsion. For typical disk conditions, the relative velocities between micron-sized grains are small, and their collisions are strongly affected by the repulsion. On the other hand, collisions between pebble-sized grains can be too energetic, leading to grain fragmentation. The aim of the present paper is to study the combined effect of the electrostatic and fragmentation barriers on dust evolution. We numerically solve the Smoluchowski coagulation–fragmentation equation for grains whose charging occurs under conditions typical for the inner disk regions, where thermal ionization operates. We find that dust fragmentation efficiently resupplies the population of small grains under the electrostatic barrier. As a result, the equilibrium abundance of submicron grains is enhanced by several orders of magnitude compared to the case of neutral dust. For some conditions with fragmentation velocities of ∼1 m s−1, macroscopic grains are completely destroyed.

We present the results of astrochemical modeling of complex organic molecules (COMs) in the ice and gas of the prestellar core L1544 with the recently updated MONACO rate equation-based model. The model includes, in particular, nondiffusive processes, new laboratory verified chemical routes for acetaldehyde and methane ice formation, and variations of H and H2 desorption energies depending on the surface coverage by H2 molecules. For the first time, we simultaneously reproduce the abundances of several oxygen-bearing COMs in the gas-phase, the approximate location of the peak of methanol emission, as well as the abundance of methanol in the icy mantles of L1544. Radical–radical reactions on the grain surface between species such as CH3, CH3O, and HCO efficiently proceed nondiffusively. COMs are delivered to the gas-phase via chemical desorption amplified by the loops of H-addition/abstraction surface reactions. However, gas-phase chemical reactions as well provide a noticeable input to the formation of COMs in the gas, but not to the COMs solid-state abundances. This particularly applies for CH3CHO and CH3OCH3. The simulated abundances of COMs in the ice are in the range 1%–2% (for methyl formate ice) or ∼0.1% (for CH3CHO and CH3OCH3) with respect to the abundance of H2O ice. We stress a similarity between the simulated abundances of icy COMs in L1544 and the abundances of COMs in the gas-phase of hot cores/corinos. We compare our nondiffusive model with the diffusive model and provide constraints for the species’ diffusion-to-desorption energy ratios.

The typical amount of molecular hydrogen (H2) in interstellar ices is not known, but significant freeze-out of H2 on dust grains is not expected. However, chemical models ubiquitously predict large amounts of H2 freeze-out in dense cloud conditions, and specialized treatments are needed to control the H2 population on grains. Here we present a numerical desorption model where the effect of weak heating events induced by cosmic rays (CRs) that heat grains to temperatures of a few tens of kelvin at high frequencies is included, improving upon earlier desorption models that only consider strong heating events (maximum grain temperature close to 100 K) that occur at a low frequency. A temperature of a few tens of kelvin is high enough to induce efficient desorption of H2, but we find that even the weak heating events do not occur often enough to lead to significant H2 desorption. Taking the weak heating events into account does affect the predicted abundances of other lightly bound species, but the effect is restricted to low column densities. We make here the canonical assumption that the grains are spherical with a radius of 0.1 μm. It is conceivable that in the case of a grain size distribution, weak heating events could provide a boost to H2 desorption coming off small grains, which are the most numerous. Further studies are still required to better quantify the role of CRs in the desorption of H2 and other weakly bound species.

Seven rotational and fine-structure transitions of the deuterated molecular ion SD+ in the X 3Σ− ground electronic state have been measured in the 271–863 GHz region in the laboratory. This ion has been produced by direct-current glow discharge using a mixture of D2S and argon in a free space cell in a temperature range of −140°C to −160°C. The rotational, centrifugal distortion, spin–spin interaction, and hyperfine constants have been determined; the standard deviation of the residuals in the fitting is 109 kHz. The set of obtained spectroscopic parameters provides a list of accurate submillimeter rest frequencies of SD+ for astronomical detection. We have investigated lines of SD+ toward the quasar PKS 1830-211 using the Atacama Large Millimeter/submillimeter Array archive, as the z = 0.89 molecular absorber exists in front of this quasar. A data set covering the 297 GHz region includes the N J = 23–12 transition at 561 GHz due to redshift, providing an upper limit of the column density N tot = 3 × 1012 cm−2 for SD+.

We present the first spatially resolved map of methanimine (CH2NH) in the prestellar core L1544 using the IRAM 30 m telescope. The 20,2–10,1 line at 127 GHz was mapped with 20″ resolution (∼2800 au), revealing extended CH2NH emission across the core. The peak line intensity coincides with the well-known c-C3H2 peak, while the integrated intensity peaks between the HNCO and dust continuum peaks due to broader linewidths in the latter region. Column densities of CH2NH are ∼(0.5–1.4×)1012 cm−2, corresponding to fractional abundances of 5 × 10−11–1 × 10−10, with a trend decreasing from the southern, carbon-chain rich region to the dust and HNCO peak in the north. Comparison with complementary molecular maps and the gas-grain chemical model of Sipilä et al. suggests that neutral–neutral gas-phase reactions and dissociative recombination dominate in the outer carbon-chain shell. This study demonstrates that CH2NH, a simple nitrogen- and carbon-bearing molecule previously detected with pointed observations in other cold cores, is present and spatially extended in the evolved prestellar core L1544. This indicates that prebiotic nitrogen-carbon chemistry continues efficiently up to the onset of gravitational collapse, providing key constraints for astrochemical models and the early stages of chemical complexity leading to amino acids.

Newly computed collisional rate coefficients for the excitation of C2 in collisions with H2, presented recently by Najar & Kalugina, are significantly larger than the values adopted previously in models for the excitation of the C2 molecule, a widely used probe of the interstellar gas density. With these new rate coefficients, we have modeled the C2 rotational distributions inferred from visible and ultraviolet absorption observations of electronic transitions of C2 toward a collection of 46 nearby background sources. The inferred gas densities in the foreground interstellar clouds responsible for the observed C2 absorption are a factor 4–7 smaller than those inferred previously, a direct reflection of the larger collisional rate coefficients computed by Najar & Kalugina. These lower-density estimates are generally in good agreement with the peak densities inferred from 3D extinction maps for the relevant sight lines. In cases where H3+ absorption has also been observed and used to estimate the cosmic-ray ionization rate (CRIR), our estimates of the latter will also decrease accordingly because the H3+ abundance is a function of the ratio of the CRIR to the gas density.

Deuterium fractionation provides a key diagnostic of the physical and chemical evolution of prestellar and protostellar cores, where it is strongly linked to CO depletion in cold, dense gas. We present the first spatially resolved maps of deuterium fraction and CO depletion in the Barnard 5 region of the Perseus molecular cloud, covering both a starless core and the protostellar core hosting the Class 0/I source IRAS 03445+3242. Using IRAM 30 m observations of N2H+(1–0), N2D+(1–0), H13CO+(1–0), and DCO+(2–1), complemented by C18O(2–1) data, we derive column density, deuterium fraction, and CO depletion maps. We find that the deuterium fraction in the abovementioned nitrogen- and carbon-bearing species increases from the protostellar to the starless core, reaching RDN2H+=0.43±0.10 and RDHCO+=0.09±0.02 in the starless core, compared with 0.15 ± 0.03 and 0.05 ± 0.01, respectively, in the protostellar core. The CO depletion factor also rises from 4.1 ± 0.1 to 5.0 ± 0.1 across the same transition. While the embedded young stellar object reduces deuteration in the dense inner gas, the less dense envelope traced by HCO+ is only slightly affected at our resolution. Our analysis confirms that CO freeze-out and the presence of a protostar jointly regulate deuterium chemistry in star-forming regions.

This paper contains a review of theoretical and empirical Italian pedagogical studies conducted from the Seventies to today on the topic of caregiver-child conversation, with particular reference to the role of adults in promoting the development of linguistic and communication skills, especially within Early Childhood Education and Care (ECEC) services for children aged zero-six years. The studies analysed here – considered a highly representative selection – show that research aimed at exploring the conversations between caregivers and children, conducted in Italy and especially over the last twenty years, has inspired reflection on linguistic interaction, also within Early Childhood Education and Care services. All in the belief that it is imperative to promote educators’ and teachers’ awareness of the key role that words play in children’s linguistic-communication and affective-emotional development, with a view to increasing the quality of ECEC. Il ruolo dei caregivers nello sviluppo linguistico-conversazionale dei bambini: una rassegna degli studi pedagogici italianiNel contributo è riportata una rassegna degli studi pedagogici italiani, sia di natura teorica che empirica, condotti dagli anni Settanta a oggi, incentrati sul tema della conversazione tra caregivers e bambini, con particolare riferimento al ruolo dell’adulto nel promuovere lo sviluppo delle competenze linguistiche e comunicative, in special modo all’interno dei servizi educativi zero-sei. Dagli studi, ritenuti maggiormente rappresentativi, selezionati in questa sede, emerge come le ricerche volte a esplorare le conversazioni tra caregivers e bambini, condotte in special modo negli ultimi vent’anni, abbiano stimolato, anche in Italia, la riflessione sulle interazioni linguistiche anche all’interno dei servizi per l’infanzia. Ciò nella convinzione che sia importante promuovere la consapevolezza di educatori e insegnanti sul ruolo-chiave della parola, sia nello sviluppo linguistico-comunicativo che emotivo e affettivo, al fine di offrire ai bambini servizi educativi di elevata qualità.