237 research outputs found
Chemical diversity of gas in distant galaxies: The metal and dust enrichment and variations within absorbing galaxies
The chemical composition of gas in galaxies can be measured in detail from
absorption spectroscopy. By studying gas in galaxies in this way, it is
possible to investigate the small and faint galaxies, which are the most
numerous in the universe. In particular, the chemical distribution of gas in
absorbing systems gives us insight into cycles of gas in and around galaxies.
Here we study chemical enrichment within 64 Damped Lyman-alpha Absorption (DLA)
systems between . We use high-resolution spectra from VLT/UVES
to infer dust depletion from relative abundances of several metals. We perform
a component-by-component analysis within DLAs, and characterise variations in
their chemical enrichment. Unlike hydrogen, the metal columns can be
characterised for individual components. We use them to derive the dust
depletion ([Zn/Fe]fit), as an indicator for chemical enrichment. We find that
some DLAs are chemically diverse within themselves, with [Zn/Fe]fit ranging up
to 0.62 dex within a single system. This suggests that absorbing gas within
these galaxies is chemically diverse. Although we do not find a clear trend of
decreasing dust depletion with redshift, we do see that the most chemically
enriched systems are at lower redshifts. We also observe evidence for dust-poor
components at all redshifts, which may be due to the accretion of pristine gas
onto galaxies. We combine the chemical and kinematic properties of the
individual gas components and observe potential signatures of infalling gas,
with low depletion at velocities below 100km/s, and outflows, with high
depletion and velocities of 600km/s. We find over-abundances of
alpha-elements (an enhancement of 0.3dex) and under-abundances of Mn in
several components, which is likely a signature of core-collapse SNe
nucleosythesis in the ISM. We observe these effects mostly at lower levels of
chemical enrichment.Comment: 56 pages, 99 figures, Accepted for publication in A&A, Abstract
abridged for arXi
Dust depletion of of metals from local to distant galaxies II: Cosmic dust-to-metal ratio and dust composition
The evolution of the cosmic dust content and the cycle between metals and
dust in the interstellar medium (ISM) play a fundamental role in galaxy
evolution. The chemical enrichment of the Universe can be traced through the
evolution of the dust-to-metals ratio (DTM) and the dust-to-gas ratio (DTG)
with metallicity. We use a novel method to determine mass estimates of the DTM,
DTG and dust composition based on our previous measurements of the depletion of
metals in different environments (the Milky Way, the Magellanic Clouds, and
damped Lyman- absorbers, DLAs, toward quasars and towards gamma-ray
bursts, GRBs), which were calculated from the relative abundances of metals in
the ISM through absorption-line spectroscopy column densities observed mainly
from VLT/UVES and X-shooter, and HST/STIS. We derive the dust extinction from
the estimated dust depletion () and compare with the
from extinction. We find that the DTM and DTG ratios increase with metallicity
and with the dust tracer [Zn/Fe]. This suggests that grain growth in the ISM is
a dominant process of dust production. The increasing trend of the DTM and DTG
with metallicity is in good agreement with a dust production and evolution
model. Our data suggest that the stellar dust yield is much lower than the
metal yield and thus that the overall amount of dust in the warm neutral medium
that is produced by stars is much lower. We find that is
overall lower than for the Milky Way and a few Magellanic
Clouds lines of sight, a discrepancy that is likely related to the presence of
carbonaceous dust. We show that the main elements that contribute to the dust
composition are, O, Fe, Si, Mg, C, S, Ni and Al for all the environments.
Abundances at low dust regimes suggest the presence of pyroxene and metallic
iron in dust.Comment: Accepted for publication in A&A. Abstract abridge
Evaluation of polygenic risk scores for breast and ovarian cancer risk prediction in BRCA1 and BRCA2 mutation carriers
Background: Genome-wide association studies (GWAS) have identified 94 common single-nucleotide polymorphisms (SNPs) associated with breast cancer (BC) risk and 18 associated with ovarian cancer (OC) risk. Several of these are also associated with risk of BC or OC for women who carry a pathogenic mutation in the high-risk BC and OC genes BRCA1 or BRCA2. The combined effects of these variants on BC or OC risk for BRCA1 and BRCA2 mutation carriers have not yet been assessed while their clinical management could benefit from improved personalized risk estimates.
Methods: We constructed polygenic risk scores (PRS) using BC and OC susceptibility SNPs identified through population-based GWAS: for BC (overall, estrogen receptor [ER]-positive, and ER-negative) and for OC. Using data from 15 252 female BRCA1 and 8211 BRCA2 carriers, the association of each PRS with BC or OC risk was evaluated using a weighted cohort approach, with time to diagnosis as the outcome and estimation of the hazard ratios (HRs) per standard deviation increase in the PRS.
Results: The PRS for ER-negative BC displayed the strongest association with BC risk in BRCA1 carriers (HR = 1.27, 95% confidence interval [CI] = 1.23 to 1.31, P = 8.2 x 10(53)). In BRCA2 carriers, the strongest association with BC risk was seen for the overall BC PRS (HR = 1.22, 95% CI = 1.17 to 1.28, P = 7.2 x 10(-20)). The OC PRS was strongly associated with OC risk for both BRCA1 and BRCA2 carriers. These translate to differences in absolute risks (more than 10% in each case) between the top and bottom deciles of the PRS distribution; for example, the OC risk was 6% by age 80 years for BRCA2 carriers at the 10th percentile of the OC PRS compared with 19% risk for those at the 90th percentile of PRS.
Conclusions: BC and OC PRS are predictive of cancer risk in BRCA1 and BRCA2 carriers. Incorporation of the PRS into risk prediction models has promise to better inform decisions on cancer risk management
Dissecting the interstellar medium of a z=6.3 galaxy: X-shooter spectroscopy and HST imaging of the afterglow and environment of the Swift GRB 210905A
The study of the properties of galaxies in the first billion years after the
Big Bang is one of the major topic of current astrophysics.
Optical/near-infrared spectroscopy of the afterglows of long Gamma-ray bursts
(GRBs) provide a powerful diagnostic tool to probe the interstellar medium
(ISM) of their host galaxies and foreground absorbers, even up to the highest
redshifts. We analyze the VLT/X-shooter afterglow spectrum of GRB 210905A,
triggered by the Swift Neil Gehrels Observatory, and detect neutral-hydrogen,
low-ionization, high-ionization, and fine-structure absorption lines from a
complex system at z=6.3118, that we associate with the GRB host galaxy. We
study the ISM properties of the host system, revealing the metallicity,
kinematics and chemical abundance pattern. The total metallicity of the z~6.3
system is [M/H]=-1.72+/-0.13, after correcting for dust-depletion and taking
into account alpha-element enhancement. In addition, we determine the overall
amount of dust and dust-to-metal mass ratio (DTM) ([Zn/Fe]_fit=0.33+/-0.09,
DTM=0.18+/-0.03). We find indications of nucleosynthesis due to massive stars
and evidence of peculiar over-abundance of aluminium. From the analysis of
fine-structure lines, we determine distances of several kpc for the
low-ionization gas clouds closest to the GRB. Those farther distances are
possibly due to the high number of ionizing photons. Using the HST/F140W image
of the GRB field, we show the GRB host galaxy as well as multiple objects
within 2" from the GRB. We discuss the galaxy structure and kinematics that
could explain our observations, also taking into account a tentative detection
of Lyman-alpha emission. Deep spectroscopic observations with VLT/MUSE and JWST
will offer the unique possibility of combining our results with the ionized-gas
properties, with the goal of better understanding how galaxies in the
reionization era form and evolve.Comment: Accepted Publication (In Press on A&A) - 22 pages, 10 figures, 6
tables - Appendix: 6 figures, 3 table
Triple-Negative Breast Cancer Risk Genes Identified by Multigene Hereditary Cancer Panel Testing
Background: Germline genetic testing with hereditary cancer gene panels can identify women at increased risk of breast cancer. However, those at increased risk of triple-negative (estrogen receptor-negative, progesterone receptor-negative, human epidermal growth factor receptor-negative) breast cancer (TNBC) cannot be identified because predisposition genes for TNBC, other than BRCA1, have not been established. The aim of this study was to define the cancer panel genes associated with increased risk of TNBC. Methods: Multigene panel testing for 21 genes in 8753 TNBC patients was performed by a clinical testing laboratory, and testing for 17 genes in 2148 patients was conducted by a Triple Negative Breast Cancer Consortium(TNBCC) of research studies. Associations between deleterious mutations in cancer predisposition genes and TNBC were evaluated using results from TNBC patients and reference controls. Results: Germline pathogenic variants in BARD1, BRCA1, BRCA2, PALB2, and RAD51D were associated with high risk (odds ratio > 5.0) of TNBC and greater than 20% lifetime risk for overall breast cancer among Caucasians. Pathogenic variants in BRIP1, RAD51C, and TP53 were associated with moderate risk (odds ratio > 2) of TNBC. Similar trends were observed for the African American population. Pathogenic variants in these TNBC genes were detected in 12.0% (3.7% non-BRCA1/2) of all participants. Conclusions: Multigene hereditary cancer panel testing can identify women with elevated risk of TNBC due to mutations in BARD1, BRCA1, BRCA2, PALB2, and RAD51D. These women can potentially benefit from improved screening, risk management, and cancer prevention strategies. Patients with mutations may also benefit from specific targeted therapeutic strategies.Peer reviewe
The cosmic build-up of dust and metals : Accurate abundances from GRB-selected star-forming galaxies at 1.7 < z < 6.3
© 2023 The Author(s), published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/The chemical enrichment of dust and metals in the interstellar medium of galaxies throughout cosmic time is one of the key driving processes of galaxy evolution. Here we study the evolution of the gas-phase metallicities, dust-to-gas (DTG) ratios, and dust-to-metal (DTM) ratios of 36 star-forming galaxies at 1.7 40 000) spectroscopic data, including three new sources, for which at least one refractory (e.g., Fe) and one volatile (e.g., S or Zn) element have been detected at S/N > 3. This is to ensure that accurate abundances and dust depletion patterns can be obtained. We first derived the redshift evolution of the dust-corrected, absorption-line-based gas-phase metallicity, [M/H] tot, in these galaxies, for which we determine a linear relation with redshift [M/H] tot(z) = (- 0.21 ± 0.04)z - (0.47 ± 0.14). We then examined the DTG and DTM ratios as a function of redshift and through three orders of magnitude in metallicity, quantifying the relative dust abundance both through the direct line-of-sight visual extinction, A V, and the derived depletion level. We used a novel method to derive the DTG and DTM mass ratios for each GRB sightline, summing up the mass of all the depleted elements in the dust phase. We find that the DTG and DTM mass ratios are both strongly correlated with the gas-phase metallicity and show a mild evolution with redshift as well. While these results are subject to a variety of caveats related to the physical environments and the narrow pencil-beam sightlines through the interstellar medium probed by the GRBs, they provide strong implications for studies of dust masses that aim to infer the gas and metal content of high-redshift galaxies, and particularly demonstrate the large offset from the average Galactic value in the low-metallicity, high-redshift regime.Peer reviewe
The cosmic build-up of dust and metals. Accurate abundances from GRB-selected star-forming galaxies at
The chemical enrichment of dust and metals in the interstellar medium (ISM)
of galaxies throughout cosmic time is one of the key driving processes of
galaxy evolution. Here we study the evolution of the gas-phase metallicities,
dust-to-gas (DTG), and dust-to-metal (DTM) ratios of 36 star-forming galaxies
at probed by gamma-ray bursts (GRBs). We compile all
GRB-selected galaxies with intermediate (R=7000) to high (R>40,000) resolution
spectroscopic data for which at least one refractory (e.g. Fe) and one volatile
(e.g. S or Zn) element have been detected at S/N>3. This is to ensure that
accurate abundances and dust depletion patterns can be obtained. We first
derive the redshift evolution of the dust-corrected, absorption-line based
gas-phase metallicity [M/H] in these galaxies, for which we
determine a linear relation with redshift . We then examine the DTG and DTM ratios as a function
of redshift and through three orders of magnitude in metallicity, quantifying
the relative dust abundance both through the direct line-of-sight visual
extinction and the derived depletion level. We use a novel method to
derive the DTG and DTM mass ratios for each GRB sightline, summing up the mass
of all the depleted elements in the dust-phase. We find that the DTG and DTM
mass ratios are both strongly correlated with the gas-phase metallicity and
show a mild evolution with redshift as well. While these results are subject to
a variety of caveats related to the physical environments and the narrow
pencil-beam sightlines through the ISM probed by the GRBs, they provide strong
implications for studies of dust masses to infer the gas and metal content of
high-redshift galaxies, and particularly demonstrate the large offset from the
average Galactic value in the low-metallicity, high-redshift regime.Comment: Accepted in A&
BRCA2 polymorphic stop codon K3326X and the risk of breast, prostate, and ovarian cancers
Background: The K3326X variant in BRCA2 (BRCA2*c.9976A>T; p.Lys3326*; rs11571833) has been found to be associated with small increased risks of breast cancer. However, it is not clear to what extent linkage disequilibrium with fully pathogenic mutations might account for this association. There is scant information about the effect of K3326X in other hormone-related cancers.
Methods: Using weighted logistic regression, we analyzed data from the large iCOGS study including 76 637 cancer case patients and 83 796 control patients to estimate odds ratios (ORw) and 95% confidence intervals (CIs) for K3326X variant carriers in relation to breast, ovarian, and prostate cancer risks, with weights defined as probability of not having a pathogenic BRCA2 variant. Using Cox proportional hazards modeling, we also examined the associations of K3326X with breast and ovarian cancer risks among 7183 BRCA1 variant carriers. All statistical tests were two-sided.
Results: The K3326X variant was associated with breast (ORw = 1.28, 95% CI = 1.17 to 1.40, P = 5.9x10- 6) and invasive ovarian cancer (ORw = 1.26, 95% CI = 1.10 to 1.43, P = 3.8x10-3). These associations were stronger for serous ovarian cancer and for estrogen receptor–negative breast cancer (ORw = 1.46, 95% CI = 1.2 to 1.70, P = 3.4x10-5 and ORw = 1.50, 95% CI = 1.28 to 1.76, P = 4.1x10-5, respectively). For BRCA1 mutation carriers, there was a statistically significant inverse association of the K3326X variant with risk of ovarian cancer (HR = 0.43, 95% CI = 0.22 to 0.84, P = .013) but no association with breast cancer. No association with prostate cancer was observed.
Conclusions: Our study provides evidence that the K3326X variant is associated with risk of developing breast and ovarian cancers independent of other pathogenic variants in BRCA2. Further studies are needed to determine the biological mechanism of action responsible for these associations
Fungal diversity associated to the olive moth, prays oleae Bernard : a survey for potential entomopathogenic fungi
Olive production is one of the main agricultural activities in Portugal. In the region of Trás-os-Montes this crop has been considerably affected by Prays oleae. In order to evaluate the diversity of fungi on P. oleae population of Trás-os-Montes olive orchards, larvae and pupae of the three annual generations (phyllophagous, antophagous and carpophagous) were collected and evaluated for fungal growth on their surface. From the 3828 larvae and pupae, a high percentage of individuals exhibited growth of a fungal agent (40.6%), particularly those from the phyllophagous generation. From all the moth generations, a total of 43 species from 24 genera were identified, but the diversity and abundance of fungal species differed between the three generations. Higher diversity was found in the carpophagous generation, followed by the antophagous and phyllophagous generations. The presence of fungi displaying entomopathogenic features was highest in the phyllophagous larvae and pupae, being B. bassiana the most abundant taxa. The first report of B. bassiana presence on P. oleae could open new strategies for the biocontrol of this major pest in olive groves, since the use of an already adapted species increases the guarantee of success of a biocontrol approach. The identification of antagonistic fungi able to control agents that cause major olive diseases, such as Verticillium dahliae, will benefit future biological control approaches for limiting this increasingly spreading pathogen.This work was supported by Science and Technology Foundation (Fundação para a Ciência e Tecnologia – FCT) project PTDC/AGR-AAM/102600/2008 “Entomopathogenic fungi associated to olive pests: isolation, characterization and selection for biological control”. The first author is grateful to the Science and Technology Foundation for the PhD grant SFRH/BD/44265/2008
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