The family pictures of our neighbours: investigating the mass function and dynamical parameters of nearby open clusters

We determine the mass functions (MFs) and the dynamical parameters of 15 nearby open clusters (OCs) using the unprecedented data set of the Gaia Early Data Release 3. We select the members of each cluster by combining the photometric (colour and magnitude) and astrometric (parallax and proper motions) parameters of stars, minimizing the contamination from Galactic field interlopers. By comparing the observed distribution of stars along the cluster main sequence with the best-fitting synthetic population, we find the present-day MF and the binary fraction of the OCs, along with their dynamical parameters like mass, half-mass radius, and half-mass relaxation time. We found that the global present-day MF of OCs are consistent with a single power-law function, $F(m)\propto m^\alpha$, with slopes $-3<\alpha<-0.6$ including both subsolar, $0.2<m/\text{M}_\odot<1$, and supersolar mass regimes. A significant correlation between the MF-slope and the ratio of age to half-mass relaxation time is evidenced, similarly to the same conclusion already observed among Galactic globular clusters. However, OCs evolve along different tracks in comparison with the globular clusters, possibly indicating primordial differences in their initial mass function (IMF). The comparison with Monte Carlo simulations suggests that all the analysed OCs could have been born with an IMF with slope $\alpha_{\text{IMF}}<-2.3$. We also show that the less evolved OCs have a MF consistent with that of the solar neighbourhood, indicating a possible connection between the dissolution of OCs and the formation of the Galactic disc.Comment: 20 pages, 14 figures, accepted for publication by MNRA

Effects of brassinosteroid (24-epibrassinolide) on yield and quality of grape (Vitis vinifera L.) 'Thompson Seedless'

Berry growth ripening process and yield are directly related with nutrition status and phytohormones during fruit growth and development stages. Brassinosteroid (24-epibrassinolide) is one of the plant growth substances that influence different physiological processes including fruit growth and development. In this study, the effect of brassinosteroid (Br) application on the yield and berry quality of 'Thompson Seedless' was investigated in a commercial vineyard, Malayer, Hamedan, Iran. Br solution concentrations of 0, 0.2, 0.4, 0.6 mg·L-1 at five stages (budbreak (S1), prebloom (S2), middle of bloom (S3), post bloom (S4) and veraison (S5) were sprayed. The results showed that the Br application has significant positive effects on bunch morphology and berry quantity and quality. Among levels of Br, the highest yields were related to the application of Br at the rate of 0.6 mg·L-1 in the post bloom and veraison stages, and the lowest was found in the bud break stage. Spraying Br in the post bloom and veraison stages had the greatest effect on berry quality. Also, the highest content of total phenol and antioxidant capacity were obtained with 0.6 mg·L-1 of Br application at veraison stage. In this study, we provided evidence to show that using steroidal plant hormones (Br) may play an essential role in improving the yield and quality of 'Thompson Seedless'

Manipulation of the Upper Respiratory Microbiota to Reduce Incidence and Severity of Upper Respiratory Viral Infections: A Literature Review.

There is a high incidence of upper respiratory viral infections in the human population, with infection severity being unique to each individual. Upper respiratory viruses have been associated previously with secondary bacterial infection, however, several cross-sectional studies analyzed in the literature indicate that an inverse relationship can also occur. Pathobiont abundance and/or bacterial dysbiosis can impair epithelial integrity and predispose an individual to viral infection. In this review we describe common commensal microorganisms that have the capacity to reduce the abundance of pathobionts and maintain bacterial symbiosis in the upper respiratory tract and discuss the potential and limitations of localized probiotic formulations of commensal bacteria to reduce the incidence and severity of viral infections