Sexual selection results in the evolution of exaggerated secondary sexual characters that can entail a viability cost. However, in species where sexual ornaments honestly reflect individual quality, ...the viability cost of secondary sexual characters may be overwhelmed by variation in individual quality, leading to expect that individuals with the largest secondary sexual characters show higher, rather than lower viability. Here, we used meta‐analyses to test whether such expected positive relationship between sexual ornamentation and viability exists in the barn swallow Hirundo rustica, which is one of the most studied model species of sexual selection under field conditions. We found a mean positive effect size of viability in relation to the expression of secondary sexual characters of 0.181 (CI: 0.084–0.278), indicating that in this species the more ornamented individuals are more viable, and therefore of high quality. Analyses of moderator variables showed similar effects in males and females, the H. r. rustica subspecies rather than others and tail length rather than other secondary sexual characters. Future research emphasis on other subspecies than the European one and secondary sexual characters than tail length may help identify the sources of heterogeneity in effect sizes.
Abstract
We are undertaking an Atacama Large Millimeter Array survey of molecular gas in galaxies selected for their strong H i absorption, so-called damped Lyα absorber (DLA)/sub-DLA galaxies. Here, ...we report CO(2–1) detection from a DLA galaxy at z = 0.716. We also present optical and near-infrared (NIR) spectra of the galaxy revealing O ii, Hα, and N ii emission lines shifted by ∼170 km s−1 relative to the DLA, and providing an oxygen abundance 3.2 times solar, similar to the absorption metallicity. We report low unobscured SFR∼1 M⊙ yr−1 given the large reservoir of molecular gas, and also modest obscured SFR $=4.5_{-2.6}^{+4.4}$ M⊙ yr−1 based on far-IR and sub-millimetre data. We determine mass components of the galaxy: logM*/M$_{\odot } = 10.80^{+0.07}_{-0.14}$, logMmol-gas/M⊙ = 10.37 ± 0.04, and logMdust/M$_{\odot } = 8.45^{+0.10}_{-0.30}$. Surprisingly, this H i absorption-selected galaxy has no equivalent objects in CO surveys of flux-selected samples. The galaxy falls off current scaling relations for the star formation rate (SFR) to molecular gas mass and CO Tully–Fisher relation. Detailed comparison of kinematical components of the absorbing, ionized, and molecular gas, combined with their spatial distribution, suggests that part of the CO gas is both kinematically and spatially decoupled from the main galaxy. It is thus possible that a major starburst in the past could explain the wide CO profile as well as the low SFR. Support for this also comes from the spectral energy distribution
favouring an instantaneous burst of age ≈0.5 Gyr. Our survey will establish whether flux-selected surveys of molecular gas are missing a key stage in the evolution of galaxies and their conversion of gas to stars.
ABSTRACT
We report on the stellar content, half-light radii and star formation rates of a sample of 10 known high-redshift (z ≳ 2) galaxies selected on strong neutral hydrogen (H i) absorption ($\log ...({\rm N_{H\, \rm {I}}\: /\: cm}^{-2})\,\gt\, 19$) towards background quasars. We use observations from the Hubble Space Telescope Wide Field Camera 3 in three broad-band filters to study the spectral energy distribution (SED) of the galaxies. Using careful quasar point spread function subtraction, we study their galactic environments, and perform the first systematic morphological characterization of such absorption-selected galaxies at high redshifts. Our analysis reveals complex, irregular hosts with multiple star-forming clumps. At a spatial sampling of 0.067 arcsec per pixel (corresponding to 0.55 kpc at the median redshift of our sample), 40 per cent of our sample requires multiple Sérsic components for an accurate modelling of the observed light distributions. Placed on the mass–size relation and the ‘main sequence’ of star-forming galaxies, we find that absorption-selected galaxies at high redshift extend known relations determined from deep luminosity-selected surveys to an order of magnitude lower stellar mass, with objects primarily composed of star-forming, late-type galaxies. We measure half-light radii in the range r1/2 ∼ 0.4 to 2.6 kpc based on the reddest band (F160W) to trace the oldest stellar populations, and stellar masses in the range log (M⋆/M⊙) ∼ 8 to 10 derived from fits to the broad-band SED. Spectroscopic and SED-based star formation rates are broadly consistent, and lie in the range $\log (\mathrm{SFR}/{\rm M}_{\odot }\, {\rm yr}^{-1}) \sim 0.0$ to 1.7.
We present ALLSMOG, the APEX Low-redshift Legacy Survey for MOlecular Gas. ALLSMOG is a survey designed to observe the CO(2 − 1) emission line with the APEX telescope, in a sample of local galaxies ...(0.01 < z < 0.03), with stellar masses in the range 8.5 < log(M*/M⊙) < 10. This paper is a data release and initial analysis of the first two semesters of observations, consisting of 42 galaxies observed in CO(2 − 1). By combining these new CO(2 − 1) emission line data with archival H i data and SDSS optical spectroscopy, we compile a sample of low-mass galaxies with well-defined molecular gas masses, atomic gas masses, and gas-phase metallicities. We explore scaling relations of gas fraction and gas consumption time-scale, and test the extent to which our findings are dependent on a varying CO/H2 conversion factor. We find an increase in the H2/H i mass ratio with stellar mass which closely matches semi-analytic predictions. We find a mean molecular gas fraction for ALLSMOG galaxies of M
H2/M
* = (0.09–0.13), which decreases with stellar mass. This decrease in total gas fraction with stellar mass is in excess of some model predictions at low stellar masses. We measure a mean molecular gas consumption time-scale for ALLSMOG galaxies of 0.4–0.7 Gyr. We also confirm the non-universality of the molecular gas consumption time-scale, which varies (with stellar mass) from ∼100 Myr to ∼2 Gyr. Importantly, we find that the trends in the H2/H i mass ratio, gas fraction, and the non-universal molecular gas consumption time-scale are all robust to a range of recent metallicity-dependent CO/H2 conversion factors.
Higher vertebrates synthesize two forms of melanin: eumelanin and pheomelanin. While the adaptive functions of eumelanin are diverse, those of pheomelanin, which is phototoxic and whose production ...consumes a key intracellular antioxidant (glutathione), are not clear apart from being involved in color patterns that confer concealment. The factors that have favored the evolution of pheomelanin thus remain a mystery, causing this pigment even to have been considered an “accident of nature.” A recent hypothesis posits that pheomelanin has evolved because it represents an alternative mechanism to remove excess dietary cysteine, which can be toxic because of its oxidation. We tested for links between pheomelanin-based color and survival in both an intraspecific study of barn swallowsHirundo rusticaand an interspecific study of 58 species of birds from North and Central America. As predicted on the basis that birds degrade excess dietary amino acids by transferring their amino group to uric acid synthesis, we found that under equal levels of uric acid in plasma, individuals or species with a higher intensity or greater proportion of plumage colored by pheomelanin (brown and chestnut coloration) had higher relative annual survival rates while controlling for the potentially confounding effects of age, sex, body size, and phylogenetic descent. Likewise, barn swallows with more intense pheomelanin-based coloration had higher prospects to survive the winter after controlling statistically for age, sex, body size, and level of uric acid. This supports the idea that pheomelanic traits evolve because of the removal of excess cysteine in nonstressful conditions, thus avoiding its toxic effects.
Knowledge about the molecular mechanisms underlying the systemic inflammation observed in psoriasis remains incomplete. In this study, we applied mass spectrometry-based proteomics to compare the ...plasma protein levels between patients with psoriasis and healthy individuals, aiming to unveil potential systemically dysregulated proteins and pathways associated with the disease. Plasma samples from adult patients with moderate-to-severe psoriasis vulgaris (N = 59) and healthy age- and sex-matched individuals (N = 21) were analyzed using liquid chromatography–tandem mass spectrometry. Patients did not receive systemic anti-psoriatic treatment for four weeks before inclusion. A total of 776 protein groups were quantified. Of these, 691 were present in at least 60% of the samples, providing the basis for the downstream analysis. We identified 20 upregulated and 22 downregulated proteins in patients with psoriasis compared to controls (p < 0.05). Multiple proteins from the complement system were upregulated, including C2, C4b, C5, and C9, and pathway analysis revealed enrichment of proteins involved in complement activation and formation of the terminal complement complex. On the other end of the spectrum, periostin was the most downregulated protein in sera from patients with psoriasis. This comprehensive proteomic investigation revealed significantly elevated levels of complement cascade proteins in psoriatic plasma, which might contribute to increased systemic inflammation in patients with psoriasis.
In a rapidly changing world, it is of fundamental importance to understand processes constraining or facilitating adaptation through microevolution. As different traits of an organism covary, genetic ...correlations are expected to affect evolutionary trajectories. However, only limited empirical data are available.
We investigate the extent to which multivariate constraints affect the rate of adaptation, focusing on four morphological traits often shown to harbour large amounts of genetic variance and considered to be subject to limited evolutionary constraints. Our data set includes unique long-term data for seven bird species and a total of 10 populations. We estimate population-specific matrices of genetic correlations and multivariate selection coefficients to predict evolutionary responses to selection. Using Bayesian methods that facilitate the propagation of errors in estimates, we compare (1) the rate of adaptation based on predicted response to selection when including genetic correlations with predictions from models where these genetic correlations were set to zero and (2) the multivariate evolvability in the direction of current selection to the average evolvability in random directions of the phenotypic space. We show that genetic correlations on average decrease the predicted rate of adaptation by 28%. Multivariate evolvability in the direction of current selection was systematically lower than average evolvability in random directions of space. These significant reductions in the rate of adaptation and reduced evolvability were due to a general nonalignment of selection and genetic variance, notably orthogonality of directional selection with the size axis along which most (60%) of the genetic variance is found.
These results suggest that genetic correlations can impose significant constraints on the evolution of avian morphology in wild populations. This could have important impacts on evolutionary dynamics and hence population persistence in the face of rapid environmental change.
Vacuolar-type adenosine triphosphatases (V-ATPases)
are electrogenic rotary mechanoenzymes structurally related to F-type ATP synthases
. They hydrolyse ATP to establish electrochemical proton ...gradients for a plethora of cellular processes
. In neurons, the loading of all neurotransmitters into synaptic vesicles is energized by about one V-ATPase molecule per synaptic vesicle
. To shed light on this bona fide single-molecule biological process, we investigated electrogenic proton-pumping by single mammalian-brain V-ATPases in single synaptic vesicles. Here we show that V-ATPases do not pump continuously in time, as suggested by observing the rotation of bacterial homologues
and assuming strict ATP-proton coupling. Instead, they stochastically switch between three ultralong-lived modes: proton-pumping, inactive and proton-leaky. Notably, direct observation of pumping revealed that physiologically relevant concentrations of ATP do not regulate the intrinsic pumping rate. ATP regulates V-ATPase activity through the switching probability of the proton-pumping mode. By contrast, electrochemical proton gradients regulate the pumping rate and the switching of the pumping and inactive modes. A direct consequence of mode-switching is all-or-none stochastic fluctuations in the electrochemical gradient of synaptic vesicles that would be expected to introduce stochasticity in proton-driven secondary active loading of neurotransmitters and may thus have important implications for neurotransmission. This work reveals and emphasizes the mechanistic and biological importance of ultraslow mode-switching.
In this paper, we analyze the current and future status of forests in Ukraine and Belarus that were contaminated after the nuclear disaster in 1986. Using several models, together with remote-sensing ...data and observations, we studied how climate change in these forests may affect fire regimes. We investigated the possibility of
137
Cs displacement over Europe by studying previous fire events, and examined three fire scenarios that depended on different emission altitudes of
137
Cs, assuming that 10% of the forests were affected by fires. Field measurements and modeling simulations confirmed that numerous radioactive contaminants are still present at these sites in extremely large quantities.
Forests in Eastern Europe are characterized by large, highly fire-prone patches that are conducive to the development of extreme crown fires. Since 1986, there has been a positive correlation between extreme fire events and drought in the two contaminated regions. Litter carbon storage in the area has doubled since 1986 due to increased tree mortality and decreased decomposition rates; dead trees and accumulating litter in turn can provide fuel for wildfires that pose a high risk of redistributing radioactivity in future years. Intense fires in 2002, 2008, and 2010 resulted in the displacement of
137
Cs to the south; the cumulative amount of
137
Cs re-deposited over Europe was equivalent to 8% of that deposited following the initial Chernobyl disaster. However, a large amount of
137
Cs still remains in these forests, which could be remobilized along with a large number of other dangerous, long-lived, refractory radionuclides. We predict that an expanding flammable area associated with climate change will lead to a high risk of radioactive contamination with characteristic fire peaks in the future. Current fire-fighting infrastructure in the region is inadequate due to understaffing and lack of funding. Our data yield the first cogent predictions for future fire incidents and provide scientific insights that could inform and spur evidence-based policy decisions concerning highly contaminated regions around the world, such as those of Chernobyl.
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