The star formation rate (SFR) is one of the main parameters used to analyze the evolution of galaxies through time. Integral field spectroscopy (IFS) is clearly the way to overcome this kind of ...limitation. We obtain integrated Halpha, ultraviolet (UV) and infrared (IR)-based SFR measurements for 272 galaxies from the C ALIFA survey at 0.005 < z < 0.03 using single-band and hybrid tracers. We aim to determine whether the extinction-corrected Halpha luminosities provide a good measure of the SFR and to shed light on the origin of the discrepancies between tracers. In the local Universe, the Halpha luminosity derived from IFS observations can be used to measure SFR, at least in statistically-significant, optically-selected galaxy samples, once stellar continuum absorption and dust attenuation effects are accounted for. The analysis of the SFR calibrations by galaxies properties could potentially be used by other works to study the impact of different selection criteria in the SFR values derived, and to disentangle selection effects from other physically motivated differences, such as environmental or evolutionary effects.
The combination of RuCl2(PPh3)3 and TEMPO affords an efficient catalytic system for the aerobic oxidation of a variety of primary and secondary alcohols, giving the corresponding aldehydes and ...ketones, in >99% selectivity in all cases. The Ru/TEMPO system displayed a preference for primary vs secondary alcohols. Results from Hammett correlation studies (ρ = −0.58) and the primary kinetic isotope effect (k H/k D = 5.1) for the catalytic aerobic benzyl alcohol oxidations are inconsistent with either an oxoruthenium (ORu) or an oxoammonium based mechanism. We postulate a hydridometal mechanism, involving a “RuH2(PPh3)3” species as the active catalyst. TEMPO acts as a hydrogen transfer mediator and is either regenerated by oxygen, under catalytic aerobic conditions, or converted to TEMPH under stoichiometric anaerobic conditions.
High-resolution electron energy loss spectroscopy has been used to study the influence of a humid environment on the collective electronic excitations of a quasifreestanding graphene monolayer ...supported on Pt(111). We found that the adsorption of water molecules at room temperature on graphene/Pt(111) is dissociative and it gives rise to adsorbate fragments. Our results indicate that these adsorbed species change the energy, the dispersion, and the lifetime of the graphene sheet plasmon. Moreover, the phase velocity of this low-energy collective mode decreases by 11% even if its lifetime notably increases. By contrast, humidity has a negligible effect on the energy of the pi plasmon at 6 eV and the unique effect induced by humidity is a significant attenuation of its intensity. Such information is essential for tailoring graphene-based plasmonic devices which should operate in ambient air humidity.
Understanding the nature of bulges in disc galaxies can provide important insights into the formation and evolution of galaxies. For instance, the presence of a classical bulge suggests a relatively ...violent history. In contrast, the presence of an inner disc instead (also referred to as a “pseudobulge”) indicates the occurrence of secular evolution processes in the main disc. However, we still lack criteria to effectively categorise bulges, limiting our ability to study their impact on the evolution of the host galaxies. Here we present a recipe to separate inner discs from classical bulges by combining four different parameters from photometric and kinematic analyses: the bulge Sérsic index nb, the concentration index C20,50, the Kormendy (1977, ApJ, 217, 406) relation and the inner slope of the radial velocity dispersion profile ∇σ. With that recipe we provide a detailed bulge classification for a sample of 45 galaxies from the integral-field spectroscopic survey CALIFA. To aid in categorising bulges within these galaxies, we perform 2D image decomposition to determine bulge Sérsic index, bulge-to-total light ratio, surface brightness and effective radius of the bulge and use growth curve analysis to derive a new concentration index, C20,50. We further extract the stellar kinematics from CALIFA data cubes and analyse the radial velocity dispersion profile. The results of the different approaches are in good agreement and allow a safe classification for approximately 95% of the galaxies. In particular, we show that our new “inner” concentration index performs considerably better than the traditionally used C50,90 when yielding the nature of bulges. We also found that a combined use of this index and the Kormendy relation gives a very robust indication of the physical nature of the bulge.
We present a study of the O III/O II ratios of star-forming galaxies drawn from Multi-Unit Spectroscopic Explorer (MUSE) data spanning a redshift range 0.28 < z < 0.85. Recently discovered Lyman ...continuum (LyC) emitters have extremely high oxygen line ratios: O IIIλ5007/O IIλλ3726, 3729 > 4. Here we aim to understand the properties and the occurrences of galaxies with such high line ratios. Combining data from several MUSE Guaranteed Time Observing (GTO) programmes, we select a population of star-forming galaxies with bright emission lines, from which we draw 406 galaxies for our analysis based on their position in the z-dependent star formation rate (SFR)–stellar mass (M∗) plane. Out of this sample 15 are identified as extreme oxygen emitters based on their O III/O II ratios (3.7%) and 104 galaxies have O III/O II > 1 (26%). Our analysis shows no significant correlation between M∗, SFR, and the distance from the SFR−M∗ relation with O III/O II. We find a decrease in the fraction of galaxies with O III/O II > 1 with increasing M∗, however, this is most likely a result of the relationship between O III/O II and metallicity, rather than between O III/O II and M∗. We draw a comparison sample of local analogues with ⟨z⟩ ≈ 0.03 from the Sloan Digital Sky Survey, and find similar incidence rates for this sample. In order to investigate the evolution in the fraction of high O III/O II emitters with redshift, we bin the sample into three redshift subsamples of equal number, but find no evidence for a dependence on redshift. Furthermore, we compare the observed line ratios with those predicted by nebular models with no LyC escape and find that most of the extreme oxygen emitters can be reproduced by low metallicity models. The remaining galaxies are likely LyC emitter candidates.
Objective
To assess the contribution of maternal factors to major birth defects after in vitro fertilisation (IVF), intracytoplasmic sperm injection (ICSI), and natural conception.
Design
...Retrospective cohort study in South Australia for the period January 1986 to December 2002.
Setting
A whole of population study.
Population
A census of all IVF and ICSI linked to registries for births, pregnancy terminations, and birth defects (diagnosed before a child's fifth birthday).
Methods
Odds ratios (ORs) for birth defects were calculated among IVF, ICSI, and natural conceptions for maternal age, parity, pre‐pregnancy BMI, smoking, pre‐existing diseases, and conditions in pregnancy, with adjustment for confounding factors.
Main outcome measures
Birth defects classified by International Classification of Diseases (ninth revision) and British Paediatric Association (ICD9‐BPA) codes.
Results
There were 2211 IVF, 1399 ICSI, and 301 060 naturally conceived births. The unadjusted prevalence of any birth defect was 7.1, 9.9, and 5.7% in the IVF, ICSI, and natural conception groups, respectively. As expected, the risk of birth defects increased with maternal age among the natural conceptions. In contrast, for IVF and ICSI combined, relative to natural conceptions, births to women aged ≤29 years had a higher risk (adjusted odds ratio, aOR 1.42; 95% confidence interval, 95% CI 1.04–1.94), births to women aged 35–39 years had no difference in risk (aOR 1.01; 95% CI 0.74–1.37), and births to women aged ≥40 years had a lower risk of defects (aOR 0.45; 95% CI 0.22–0.92). Defects were also elevated for nulliparity, anaemia, and urinary tract infection in births after ICSI, but not after IVF.
Conclusions
The usual age–birth defect relationship is reversed in births after IVF and ICSI, and the associations for other maternal factors and defects vary between IVF and ICSI.
Tweetable
Risk of birth defects in women over 40 years is lower after infertility treatment than for natural conceptions.
Tweetable
Risk of birth defects in women over 40 years is lower after infertility treatment than for natural conceptions.
We present an improved version of FIT3D, a fitting tool for the analysis of the spectroscopic properties of the stellar populations and the ionized gas derived from moderate resolution spectra of ...galaxies. This tool was developed to analyze integral field spectroscopy data and it is the basis of P 3D, a pipeline used in the analysis of CALIFA, MaNGA, and SAMI data. We describe the philosophy and each step of the fitting procedure. We present an extensive set of simulations in order to estimate the precision and accuracy of the derived parameters for the stellar populations and the ionized gas. We report on the results of those simulations. Finally, we compare the results of the analysis using FIT3D with those provided by other widely used packages, and we find that the parameters derived by FIT3D are fully compatible with those derived using these other tools.
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