Key message
A comparative analysis of the genus
Flaveria
showed a C
4
evolutionary process in which the anatomical and metabolic features of C
4
photosynthesis were gradually acquired through C
3
–C
...4
intermediate stages.
C
4
photosynthesis has been acquired in multiple lineages of angiosperms during evolution to suppress photorespiration. Crops that perform C
4
photosynthesis exhibit high rates of CO
2
assimilation and high grain production even under high-temperature in semiarid environments; therefore, engineering C
4
photosynthesis in C
3
plants is of great importance in the application field. The genus
Flaveria
contains a large number of C
3
, C
3
–C
4
intermediate, C
4
-like, and C
4
species, making it a good model genus to study the evolution of C
4
photosynthesis, and these studies indicate the direction for C
4
engineering. C
4
photosynthesis was acquired gradually through the C
3
–C
4
intermediate stage. First, a two-celled C
2
cycle called C
2
photosynthesis was acquired by localizing glycine decarboxylase activity in the mitochondria of bundle sheath cells. With the development of two-cell metabolism, anatomical features also changed. Next, the replacement of the two-celled C
2
cycle by the two-celled C
4
cycle was induced by the acquisition of cell-selective expression in addition to the upregulation of enzymes in the C
4
cycle during the C
3
–C
4
intermediate stage. This was supported by an increase in cyclic electron transport activity in response to an increase in the ATP/NADPH demand for metabolism. Suppression of the C
3
cycle in mesophyll cells was induced after the functional establishment of the C
4
cycle, and optimization of electron transport by suppressing the activity of photosystem II also occurred during the final phase of C
4
evolution.
ABSTRACT We investigate the physical conditions of ionized gas in high-z star-forming galaxies using diagnostic diagrams based on the rest-frame optical emission lines. The sample consists of 701 ...galaxies with an H detection at , from the Fiber Multi-Object Spectrograph (FMOS)-COSMOS survey, that represent the normal star-forming population over the stellar mass range , with those at being well sampled. We confirm an offset of the average location of star-forming galaxies in the Baldwin-Phillips-Terlevich (BPT) diagram ( versus ), primarily toward higher , compared with local galaxies. Based on the S ii ratio, we measure an electron density ( ), which is higher than that of local galaxies. Based on comparisons to theoretical models, we argue that changes in emission-line ratios, including the offset in the BPT diagram, are caused by a higher ionization parameter both at fixed stellar mass and at fixed metallicity, with additional contributions from a higher gas density and possibly a hardening of the ionizing radiation field. Ionization due to active galactic nuclei is ruled out as assessed with Chandra. As a consequence, we revisit the mass-metallicity relation using and a new calibration including as recently introduced by Dopita et al. Consistent with our previous results, the most massive galaxies ( ) are fully enriched, while those at lower masses have metallicities lower than local galaxies. Finally, we demonstrate that the stellar masses, metallicities, and star formation rates of the FMOS sample are well fit with a physically motivated model for the chemical evolution of star-forming galaxies.
We use the large COSMOS sample of galaxies to study in an internally self-consistent way the change in the number densities of quenched early-type galaxies (Q-ETGs) of a given size over the redshift ...interval 0.2 < z < 1 in order to study the claimed size evolution of these galaxies. In a stellar mass bin at 10 super(10.5) < M sub(galaxy) < 10 super(11) M sub(middot in circle), we see no change in the number density of compact Q-ETGs over this redshift range, while in a higher mass bin at >10 super(11) M sub(middot in circle), where we would expect merging to be more significant, we find a small decrease, by ~30%. In both mass bins, the increase of the median sizes of Q-ETGs with time is primarily caused by the addition to the size function of larger and more diffuse Q-ETGs. At all masses, compact Q-ETGs become systematically redder toward later epochs, with a (U - V) color difference which is consistent with a passive evolution of their stellar populations, indicating that they are a stable population that does not appreciably evolve in size. We find furthermore, at all epochs, that the larger Q-ETGs (at least in the lower mass bin) have average rest-frame colors that are systematically bluer than those of the more compact Q-ETGs, suggesting that the former are indeed younger than the latter. The idea that new, large, Q-ETGs are responsible for the observed growth in the median size of the population at a given mass is also supported by analysis of the sizes and number of the star-forming galaxies that are expected to be the progenitors of the new Q-ETGs over the same period. In the low mass bin, the new Q-ETGs appear to have similar to 30% smaller half-light radii than their star-forming progenitors. This is likely due to the fading of their disks after they cease star formation. Comparison with higher redshifts shows that the median size of newly quenched galaxies roughly scales, at constant mass, as (1 + z) super(-1). We conclude that the dominant cause of the size evolution seen in the Q-ETG population is that the average sizes and thus stellar densities of individual Q-ETGs roughly scale with the average density of the universe at the time when they were quenched, and that subsequent size changes in individual objects, through merging or other processes, are of secondary importance, especially at masses below 10 super(11) M sub(middot in circle).
We present the results of a new search for bright star-forming galaxies at redshift z ... 7 within the UltraVISTA second data release (DR2) and UKIDSS (UKIRT Infrared Deep Sky Survey) UDS (Ultra Deep ...Survey) DR10 data, which together provide 1.65 deg^sup 2^ of near-infrared imaging with overlapping optical and Spitzer data. Using a full photometric redshift analysis, to identify high-redshift galaxies and reject contaminants, we have selected a sample of 34 luminous (-22.7<M^sub UV^<-21.2) galaxies with 6.5 < z < 7.5. Crucially, the deeper imaging provided by UltraVISTA DR2 confirms all of the robust objects previously uncovered by Bowler et al., validating our selection technique. Our new expanded galaxy sample includes the most massive galaxies known at z ... 7, with M* ... 10^sup 10^ M..., and the majority are resolved, consistent with larger sizes (r^sub ...^ ... 1-1.5 kpc) than displayed by less massive galaxies. From our final robust sample, we determine the form of the bright end of the rest-frame UV galaxy luminosity function (LF) at z ... 7, providing strong evidence that it does not decline as steeply as predicted by the Schechter-function fit to fainter data. We exclude the possibility that this is due to either gravitational lensing, or significant contamination of our galaxy sample by active galactic nuclei (AGN). Rather, our results favour a double power-law form for the galaxy LF at high redshift, or, more interestingly, an LF which simply follows the form of the dark matter halo mass function at bright magnitudes. This suggests that the physical mechanism which inhibits star formation activity in massive galaxies (i.e. AGN feedback or some other form of 'mass quenching') has yet to impact on the observable galaxy LF at z ... 7, a conclusion supported by the estimated masses of our brightest galaxies which have only just reached a mass comparable to the critical 'quenching mass' of M* ... 10^sup 10.2^ M... derived from studies of the mass function of star-forming galaxies at lower redshift. (ProQuest: ... denotes formulae/symbols omitted.)
Abstract
The Cosmic Evolution Survey (COSMOS) has become a cornerstone of extragalactic astronomy. Since the last public catalog in 2015, a wealth of new imaging and spectroscopic data have been ...collected in the COSMOS field. This paper describes the collection, processing, and analysis of these new imaging data to produce a new reference photometric redshift catalog. Source detection and multiwavelength photometry are performed for 1.7 million sources across the 2 deg
2
of the COSMOS field, ∼966,000 of which are measured with all available broadband data using both traditional aperture photometric methods and a new profile-fitting photometric extraction tool,
The Farmer
, which we have developed. A detailed comparison of the two resulting photometric catalogs is presented. Photometric redshifts are computed for all sources in each catalog utilizing two independent photometric redshift codes. Finally, a comparison is made between the performance of the photometric methodologies and of the redshift codes to demonstrate an exceptional degree of self-consistency in the resulting photometric redshifts. The
i
< 21 sources have subpercent photometric redshift accuracy and even the faintest sources at 25 <
i
< 27 reach a precision of 5%. Finally, these results are discussed in the context of previous, current, and future surveys in the COSMOS field. Compared to COSMOS2015, it reaches the same photometric redshift precision at almost one magnitude deeper. Both photometric catalogs and their photometric redshift solutions and physical parameters will be made available through the usual astronomical archive systems (ESO Phase 3, IPAC-IRSA, and CDS).
The tensile, flexural, and fracture toughness properties of seven chemically different amine-cured epoxy resins were studied. Positron annihilation lifetime and pressure–volume–temperature (PVT) ...experiments were performed on each epoxy resin to characterize the average size and fraction, respectively, of free-volume holes. A negative correlation between hole fraction and hole size was revealed for these chemically different epoxy resins. Better tensile and flexural mechanical properties (higher tensile modulus and lower tensile strain at break; higher flexural modulus, higher flexural strength, and lower flexural strain at break) were clearly observed for epoxy resins with smaller hole size and higher hole fraction. However, no clear relationship between fracture toughness and hole properties was found. The correlations between (tensile and flexural) static mechanical properties and hole properties for chemically different epoxy resins should provide guidance for further improvements in the mechanical properties of carbon-fiber-reinforced polymers.
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PURPOSEAlthough exercising with others might have health benefits, no previous study has comprehensively examined associations of exercise arrangement with physical activity (PA), physical function ...(PF), and mental health (MH). We examined whether PA, PF, and MH are better when exercising with others than when exercising alone or not exercising.
METHODSWe analyzed cross-sectional data from 7759 (4007 men and 3752 women) nondisabled residents age 65 to 84 yr. PA, PF, and MH were assessed with the International Physical Activity Questionnaire-Short Form (PA sufficiency defined as ≥150 min·wk of moderate-to-vigorous PA), Motor Fitness Scale (higher PF defined as total score ≥12 in men and ≥10 in women), and World Health Organization-Five Well-Being Index (better MH defined as a total score ≥13), respectively. Exercise arrangement was classified as “nonexerciser,” “exercising alone,” and “exercising with others.” Using multilevel logistic regression analyses, we examined independent associations of exercise arrangement with PA, PF, and MH.
RESULTSCompared with exercising alone, the multivariate-adjusted odds ratios (95% confidence interval) among nonexercisers and those exercising with others were 0.21 (0.17–0.25) and 1.32 (1.04–1.67), respectively, for PA sufficiency, 0.47 (0.40–0.57) and 1.12 (0.94–1.34) for higher PF, and 0.69 (0.58–0.82) and 1.45 (1.17–1.79) for better MH, respectively, in men. In women, the corresponding odds ratios were 0.37 (0.30–0.46) and 1.31 (1.01–1.70) for PA sufficiency, 0.66 (0.54–0.80) and 1.08 (0.88–1.32) for higher PF, and 0.70 (0.58–0.85) and 1.27 (1.03–1.56) for better MH, respectively.
CONCLUSIONSExercising alone and with others were better than no exercise for maintaining better PA, PF, and MH in both sexes. Although exercise arrangement had little effect on maintaining PF, exercising with others appears to enhance PA levels and MH in both sexes.
Production of diploid males is disadvantageous for populations of haplodiploid species, because it increases the genetic load and decreases fitness. In social species, the damage becomes more serious ...because of increased colony mortality and decreased colony growth rates. As a parameter to quantify diploid male production, the proportion of diploids that are males,
Φ
, has been estimated using multiple-loci marker genotypes. In these studies,
Φ
is separately estimated for individual marker locus, and then the estimates are averaged over marker loci. In this paper, we propose a simple method for combining genotypes of multiple-marker loci to obtain a single estimate of
Φ
, which is expected to enhance the quality of estimate. As an application,
Φ
in a threatened bumble bee population in Japan is estimated from genotype data of multiple microsatellite loci. Under the separate analysis of individual marker locus the detectability of diploid males, measured by the probability that a diploid is heterozygous, is within the range of 0.196–0.554, whereas the detectability from the proposed method increases to 0.834, giving an estimate of
Φ
with a higher degree of precision.
We present an investigation into how well the properties of the accretion flow on to a supermassive black hole may be coupled to those of the overlying hot corona. To do so, we specifically measure ...the characteristic spectral index, Γ, of a power-law energy distribution, over an energy range of 2-10 keV, for X-ray selected, broad-lined radio-quiet active galactic nuclei (AGN) up to z ∼ 2 in Cosmic Evolution Survey (COSMOS) and Extended Chandra Deep Field South (E-CDF-S). We test the previously reported dependence between Γ and black hole mass, full width at half-maximum (FWHM) and Eddington ratio using a sample of AGN covering a broad range in these parameters based on both the Mg ii and Hα emission lines with the later afforded by recent near-infrared spectroscopic observations using Subaru/Fibre Multi Object Spectrograph. We calculate the Eddington ratios, λEdd, for sources where a bolometric luminosity (L
Bol) has been presented in the literature, based on spectral energy distribution fitting, or, for sources where these data do not exist, we calculate L
Bol using a bolometric correction to the X-ray luminosity, derived from a relationship between the bolometric correction and L
X/L
3000. From a sample of 69 X-ray bright sources (>250 counts), where Γ can be measured with greatest precision, with an estimate of L
Bol, we find a statistically significant correlation between Γ and λEdd, which is highly significant with a chance probability of 6.59× 10−8. A statistically significant correlation between Γ and the FWHM of the optical lines is confirmed, but at lower significance than with λEdd indicating that λEdd is the key parameter driving conditions in the corona. Linear regression analysis reveals that Γ = (0.32 ± 0.05) log10λEdd + (2.27 ± 0.06) and Γ = (−0.69 ± 0.11) log10(FWHM/km s−1) + (4.44 ± 0.42). Our results on Γ-λEdd are in very good agreement with previous results. While the Γ-λEdd relationship means that X-ray spectroscopy may be used to estimate black hole accretion rate, considerable dispersion in the correlation does not make this viable for single sources, however could be valuable for large X-ray spectral samples, such as those to be produced by eROSITA.
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