We present a theoretical study on the metallicity dependence of the initial−to−final mass relation and its influence on white dwarf age determinations. We compute a grid of evolutionary sequences from the main sequence to ∼ 3 000 K on the white dwarf cooling curve, passing through all intermediate stages. During the thermallypulsing asymptotic giant branch no third dredge-up episodes are considered and thus the photospheric C/O ratio is below unity for sequences with metallicities larger than Z = 0.0001. We consider initial metallicities from Z = 0.0001 to Z = 0.04, accounting for stellar populations in the galactic disk and halo, with initial masses below ∼ 3M ⊙ . We found a clear dependence of the shape of the initial−to−final mass relation with the progenitor metallicity, where metal rich progenitors result in less massive white dwarf remnants, due to an enhancement of the mass loss rates associated to high metallicity values. By comparing our theoretical computations with semi empirical data from globular and old open clusters, we found that the observed intrinsic mass spread can be accounted for by a set of initial−to−final mass relations characterized by different metallicity values. Also, we confirm that the lifetime spent before the white dwarf stage increases with metallicity. Finally, we estimate the mean mass at the top of the white dwarf cooling curve for three globular clusters NGC 6397, M4 and 47 Tuc, around 0.53M ⊙ , characteristic of old stellar populations. However, we found different values for the progenitor mass, lower for the metal poor cluster, NGC 6397, and larger for the younger and metal rich cluster 47 Tuc, as expected from the metallicity dependence of the initial−to−final mass relation.

We explore the physics of crystallization in the deep interiors of white dwarf stars using the color-magnitude diagram and luminosity function constructed from proper motion cleaned Hubble Space Telescope photometry of the globular cluster NGC 6397. We demonstrate that the data are consistent with the theory of crystallization of the ions in the interior of white dwarf stars and provide the first empirical evidence that the phase transition is first order: latent heat is released in the process of crystallization as predicted by van Horn (1968). We outline how this data can be used to observationally constrain the value of Γ ≡ E Coulomb /E thermal near the onset of crystallization, the central carbon/oxygen abundance, and the importance of phase separation. Subject headings: white dwarfs -dense matter -equation of state

The 2021 re-emergence of yellow fever in non-human primates in the state of Rio Grande do Sul (RS), southernmost Brazil, resulted in the death of many howler monkeys (genus Alouatta) and led the state to declare a Public Health Emergency of State Importance, despite no human cases reported. In this study, near-complete genomes of yellow fever virus (YFV) recovered from the outbreak were sequenced and examined aiming at a better understanding of the phylogenetic relationships and the spatio-temporal dynamics of the virus distribution. Our results suggest that the most likely sequence of events involved the reintroduction of YFV from the state of São Paulo to RS through the states of Paraná and Santa Catarina, by the end of 2020. These findings reinforce the role of genomic surveillance in determining the pathways of distribution of the virus and in providing references for the implementation of preventive measures for populations in high risk areas.

We report our study of features at the observed red end of the white dwarf cooling sequences for three Galactic globular clusters: NGC 6397, 47 Tucanae and M 4. We use deep colour-magnitude diagrams constructed from archival Hubble Space Telescope (ACS) to systematically investigate the blue turn at faint magnitudes and the age determinations for each cluster. We find that the age difference between NGC 6397 and 47 Tuc is 1.98 +0.44 −0.26 Gyr, consistent with the picture that metal-rich halo clusters were formed later than metal-poor halo clusters. We self-consistently include the effect of metallicity on the progenitor age and the initial-to-final mass relation. In contrast with previous investigations that invoked a single white dwarf mass for each cluster, the data shows a spread of white dwarf masses that better reproduce the shape and location of the blue turn. This effect alone, however, does not completely reproduce the observational data -the blue turn retains some mystery. In this context, we discuss several other potential problems in the models. These include possible partial mixing of H and He in the atmosphere of white dwarf stars, the lack of a good physical description of the collision-induced absorption process and uncertainties in the opacities at low temperatures. The latter are already known to be significant in the description of the cool main sequence. Additionally, we find that the present day local mass function of NGC 6397 is consistent with a top-heavy type, while 47 Tuc presents a bottom-heavy profile.

We present multichromatic isochrone fits to the colour magnitude data of the globular cluster NGC 6366, based on HST ACS/WFC and SOAR photometric data. We corrected the photometric data for differential reddening and calculated the mean ridge line of the colour magnitude diagrams. We compared the isochrones of Dartmouth Stellar Evolution Database and PAdova and TRieste Stellar Evolution Code both with microscopic diffusion starting on the main sequence. Bracketing all previous determinations of this cluster we tested metallicities from [Fe/H]=-1.00 to [Fe/H]=-0.50, and ages from 9 to 13 Gyrs. After determining the total to selective extinction ratio only from stars belonging to this cluster, R V = 3.06±0.14, we found the parameters for this cluster to be E(B − V ) = 0.69 ± 0.02(int) ±0.04(ext), (m − M ) V = 15.02 ± 0.07(int) ±0.13(ext), Age = 11 ± 1.15Gyr. Evolutionary models fail to reproduce the low-T eff sequence in multi-band colour magnitude diagrams, indicating that they still have an incomplete physics. We found that the Dartmouth Stellar Evolution Database isochrones fit better the sub giant branch and low main sequence than the PAdova and TRieste Stellar Evolution Code.

Here we report the presence and expression levels of the vanC 1 and vanC 2/3 genes in vancomycin-susceptible strains of Enterococcus faecalis. The vanC 1 and vanC 2/3 genes were located in the plasmid DNA and on the chromosome, respectively. Specific mRNA of the vanC 1 gene was detected in one of these strains. Additionally, analysis of the vanC gene sequences showed that these genes are related to the vanC genes of Enterococcus gallinarum and Enterococcus casseliflavus. The presence of vanC genes is useful for the identification of E. gallinarum and E. casseliflavus. Moreover, this is the first report of vanC mRNA in E. faecalis.

We build differential-reddening maps for 66 Galactic globular clusters (GCs) with archival HST WFC/ACS F606W and F814W photometry. Because of the different GC sizes (characterised by the half-light radius R h ) and distances to the Sun, the WFC/ACS field of view (200 ×200 ) coverage (R obs ) lies in the range 1 R obs /R h 15 for about 85% of the sample, with about 10% covering only the inner (R obs R h ) parts. We divide the WFC/ACS field of view across each cluster in a regular cell grid, and extract the stellar-density Hess diagram from each cell, shifting it in colour and magnitude along the reddening vector until matching the mean diagram. Thus, the maps correspond to the internal dispersion of the reddening around the mean. Depending on the number of available stars (i.e. probable members with adequate photometric errors), the angular resolution of the maps range from ≈ 7 × 7 to ≈ 20 × 20 . We detect spatially-variable extinction in the 66 globular clusters studied, with mean values ranging from δE(B − V ) ≈ 0.018 (NGC 6981) up to δE(B − V ) ≈ 0.16 (Palomar 2). Differential-reddening correction decreases the observed foreground reddening and the apparent distance modulus but, since they are related to the same value of E(B − V ), the distance to the Sun is conserved. Fits to the mean-ridge lines of the highly-extincted and photometrically scattered globular cluster Palomar 2 show that age and metallicity also remain unchanged after the differential-reddening correction, but measurement uncertainties decrease because of the reduced scatter. The lack of systematic variations of δE(B − V ) with both the foreground reddening and the sampled cluster area indicates that the main source of differential reddening is interstellar.

Sapajus nigritus are non-human primates which are widespread in South America. They are omnivores and live in troops of up to 40 individuals. The oral cavity is one of the main entry routes for microorganisms, including viruses. Our study proposed the identification of viral sequences from oral swabs collected in a group of capuchin monkeys (n = 5) living in a public park in a fragment of Mata Atlantica in South Brazil. Samples were submitted to nucleic acid extraction and enrichment, which was followed by the construction of libraries. After high-throughput sequencing and contig assembly, we used a pipeline to identify 11 viral families, which are Herpesviridae, Parvoviridae, Papillomaviridae, Polyomaviridae, Caulimoviridae, Iridoviridae, Astroviridae, Poxviridae, and Baculoviridae, in addition to two complete viral genomes of Anelloviridae and Genomoviridae. Some of these viruses were closely related to known viruses, while other fragments are more distantly related, with 50% of identity or less to the currently available virus sequences in databases. In addition to host-related viruses, insect and small vertebrate-related viruses were also found, as well as plant-related viruses, bringing insights about their diet. In conclusion, this viral metagenomic analysis reveals, for the first time, the profile of viruses in the oral cavity of wild, free ranging capuchin monkeys.