We used our database of VLT-UVES quasar spectra to build up a sample of 70 Damped Lyman-\alpha (DLA) or strong sub-DLA systems with total neutral hydrogen column densities of \log N(H I) \ga 20 and ...redshifts in the range 1.7<z_{\rm abs}<4.3. For each of the systems, we measured the metallicities relative to solar in an homogeneous manner, X/H (with {\rm X}={\rm Zn}, or S or Si), and the velocity widths of low-ionization line profiles, \Delta V. For the first time, we provide evidence for a correlation between DLA metallicity and line profile velocity width, which is detected at the 6.1\sigma significance level. This confirms the trend previously observed in a much smaller sample by Wolfe & Prochaska (1998). The best-fit linear relation is {\rm X}/{\rm H}=1.55(\pm 0.12) \log\Delta V-4.33(\pm 0.23), with \Delta V expressed in km s super(-1). The slope of the DLA velocity- metallicity relation is the same within uncertainties between the higher ( 2.43$--> z_{\rm abs}>2.43) and the lower ( z_{\rm abs}\le 2.43) redshift halves of our sample. However, the two populations of systems are statistically different. There is a strong redshift evolution in the sense that the median metallicity and median velocity width increase with decreasing redshift. We argue that the existence of a DLA velocity- metallicity correlation, over more than a factor of 100 spread in metallicity, is probably the consequence of an underlying mass-metallicity relation for the galaxies responsible for DLA absorption lines. Assuming a simple linear scaling of the galaxy luminosity with the mass of the dark- matter halo, we find that the slope of the DLA velocity-metallicity relation is consistent with that of the luminosity-metallicity relation derived for local galaxies. If the galaxy dynamical mass is indeed the dominant factor setting up the observed DLA velocity-metallicity correlation, then the DLA systems exhibiting the lowest metallicities among the DLA population should, on average, be associated with galaxies of lower masses (e.g., gas-rich dwarf galaxies). In turn, these galaxies should have the lowest luminosities among the DLA galaxy population. This could explain the difficulties of detecting high-redshift DLA galaxies in emission.
Trait polymorphism can evolve as a consequence of frequency-dependent selection. Coevolutionary interactions between hosts and parasites may lead to selection on both to evolve extreme phenotypes ...deviating from the norm, through disruptive selection.
Here, we show through detailed field studies and experimental procedures that the ashy-throated parrotbill (Paradoxornis alphonsianus) and its avian brood parasite, the common cuckoo (Cuculus canorus), have both evolved egg polymorphism manifested in discrete immaculate white, pale blue, and blue egg phenotypes within a single population. In this host-parasite system the most common egg colours were white and blue, with no significant difference in parasitism rates between hosts laying eggs of either colour. Furthermore, selection on parasites for countering the evolution of host egg types appears to be strong, since ashy-throated parrotbills have evolved rejection abilities for even partially mimetic eggs.
The parrotbill-cuckoo system constitutes a clear outcome of disruptive selection on both host and parasite egg phenotypes driven by coevolution, due to the cost of parasitism in the host and by host defences in the parasite. The present study is to our knowledge the first to report the influence of disruptive selection on evolution of discrete phenotypes in both parasite and host traits in an avian brood parasitism system.
Background
A new technology in cancer treatment, the MR-linac, provides online magnetic resonance-guided radiotherapy (MRgRT) that combines real-time visualization of the tumor and surrounding tissue ...with radiation therapy to deliver treatment more accurately. Online MRgRT makes it possible to minimize treatment volume, potentially reducing acute treatment toxicity. Patient-reported outcomes (PRO) add the patient perspective to evaluating treatment toxicity related to new technology. The objective of this mixed-methods study was to develop and explore the content validity of a set of PRO items to evaluate acute pelvic toxicity to radiotherapy including online MRgRT.
Methods
A literature review and chart audit were conducted to identify symptomatic adverse events (AEs) to be selected from the Patient-Reported Outcomes Version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE) library and European Organisation for Research and Treatment of Cancer (EORTC) item library. To validate the content, the item set was applied in a prospective pilot cohort of patients referred for primary pelvic RT with curative intent. Patients reported symptoms weekly during RT (4–8 weeks) and the subsequent 4 weeks. Follow-up reports were collected at 8, 12, and 24 weeks after RT. To ensure symptom coverage clinician-reported toxicity and individual patient interviews were conducted. The symptomatic AEs were included in the final item set if ≥20% of patients reported them.
Results
Eighteen acute symptomatic AEs were selected for the initial item set. Forty patients (32 prostate cancer, 8 cervical cancer) were included in the pilot study. Patients with prostate cancer and those with cervical cancer both reported all 18 acute AEs. However, vomiting was not reported by > 20% of patients thus excluded from the item set. Adding a few diagnosis-specific AEs to the final item set was required for both prostate and cervical cancer patients.
Conclusions
A PRO item set for patients with pelvic cancer treated with radiotherapy with a curative intent was developed and content validity explored. In the pilot study, the item set captured the most common acute symptomatic AEs for patients with prostate and cervical cancer related to pelvic RT including online MRgRT. Further validation of the content in broader disease sites would be needed in future studies.
Among avian species, the differential cost entailed by either sex in competition for mates has been regarded as the main evolutionary influence on sex differences in mortality rates. However, ...empirical evidence suggests that sex‐biased adult mortality is mainly related to differential energy investment in gamete production, with a greater annual mass devoted to egg production leading to higher female mortality. We explicitly tested the generality of this pattern in a comparative framework. Annual egg production can be relatively large in some species (up to 200% of female body mass) and annual mortality is generally biased toward females. We showed that greater annual egg productivity resulted in higher mortality rates of females relative to males. Mating system was secondarily important, with species in which males were more involved in mating competition having more equal mortality rates between the sexes. However, both traits explained only a limited fraction of the interspecific variation in female‐biased mortality. Other traits, such as sexual size dimorphism and parental care, had much weaker influences on female‐biased mortality. Our results suggest that both annual mass devoted to gamete production by females and mating system contribute to the evolution of the fundamental life‐history trade‐off between reproduction and survival in avian taxa.
The reionisation of the Universe is a process that is thought to have ended around z ~ 6, as inferred from spectroscopy of distant bright background sources, such as quasars (QSO) and gamma-ray burst ...(GRB) after glows. We aim to measure the degree of ionisation of the intergalactic medium (1GM) between z = 5.02-5.84 and to study the chemical abundance pattern and dust content of its host galaxy. We estimated the UV continuum of the GRB afterglow using a power-law extrapolation, then measured the flux decrement due to absorption at Lyalpha, beta, and gamma wavelength regions. Our measurements confirm that the Universe is already predominantly ionised over the redshift range probed in this work, but was slightly more neutral at z > 5.6. GRBs are useful probes of the ionisation state of the 1GM in the early Universe, but because of internal scatter we need a larger statistical sample to draw robust conclusions.
The incorporation of aromatic plants into nests by birds is suspected to constitute an example of preventative medicine use, whereby the phytochemical compounds within plants reduce infestation by ...parasites and increase offspring condition 1,2. In China, russet sparrows (Passer cinnamomeus) incorporate wormwood (Artemisia verlotorum) leaves into their nests around the same time that local people hang wormwood from their doors as a traditional custom during the Dragon Boat Festival. The belief that this behaviour confers protection against ill health 3 is supported by the description of anti-parasite compounds in wormwood 4. It has been suggested that the incorporation of fresh wormwood leaves into nests may serve a similar function for sparrows. Here we show that sparrows choose nest location and resupply established nests with fresh wormwood leaves using olfactory cues, that nests containing wormwood leaves have lower ectoparasite loads, and that nests with more wormwood leaves produce heavier chicks. Our results indicate that sparrows use wormwood as a preventative medicine to control ectoparasites and improve the body mass of their offspring.
Several bird species incorporate aromatic plant material into their nests, but why they do this is a subject of ongoing debate. A new study by Yang et al. indicates that birds use wormwood to decrease parasite loads within nests and increase offspring condition.
ABSTRACT
While emission-selected galaxy surveys are biased towards the most luminous part of the galaxy population, absorption selection is a potentially unbiased galaxy selection technique with ...respect to luminosity. However, the physical properties of absorption-selected galaxies are not well characterized. Here, we study the excitation conditions in the interstellar medium (ISM) in damped Ly α (DLA) absorption-selected galaxies. We present a study of the CO spectral-line energy distribution (SLED) in four high-metallicity absorption-selected galaxies with previously reported CO detections at intermediate (z ∼ 0.7) and high (z ∼ 2) redshifts. We find further evidence for a wide variety of ISM conditions in these galaxies. Two out of the four galaxies show CO SLEDs consistent with that of the Milky Way inner disc. Interestingly, one of these galaxies is at z ∼ 2 and has a CO SLED below that of main-sequence galaxies at similar redshifts. The other two galaxies at z > 2 show more excited ISM conditions, with one of them showing thermal excitation of the mid-J (J = 3, 4) levels, similar to that seen in two massive main-sequence galaxies at these redshifts. Overall, we find that absorption selection traces a diverse population of galaxies.
We report on further observations of the field of the quasar Q 1218+0832. Geier et al. (2019, A&A, 625, L9) presented the discovery of the quasar resulting from a search for quasars reddened and ...dimmed by dust in foreground damped Lyman-
α
absorbers (DLAs). The DLA is remarkable by having a very large H
I
column density close to 10
22
cm
−2
. Its dust extinction curve shows the 2175 Å bump known from the Local Group. It also shows absorption from cold gas exemplified by C
I
and CO molecules. For this paper, we present narrow-band observations of the field of Q 1218+0832 and also use an archival
Hubble
Space Telescope (HST) image to search for the galaxy counterpart of the DLA. No emission from the DLA galaxy is found in either the narrow-band imaging or in the HST image. In the HST image, we could probe down to an impact parameter of 0.3 arcsec and a 3-
σ
detection limit of 26.8 mag per arcsec
2
. In the narrow-band image, we probed down to a 0 arcsec impact parameter and detected nothing down to a 3-
σ
detection limit of about 3 × 10
−17
erg s
−1
cm
−2
. We did detect a bright Lyman-
α
emitter 59 arcsec south of Q 1218+0832 with a flux of 3 × 10
−16
erg s
−1
cm
−2
. We conclude that the DLA galaxy must be located at a very small impact parameter (< 0.3 arcsec, 2.5 kpc) or it is optically dark. Also, the DLA galaxy most likely is part of a galaxy group.
ABSTRACT Gamma-ray bursts (GRBs) offer a route to characterizing star-forming galaxies and quantifying high-z star formation that is distinct from the approach of traditional galaxy surveys: GRB ...selection is independent of dust and probes even the faintest galaxies which can evade detection in flux-limited surveys. However, the exact relation between the GRB rate and the star formation rate (SFR) throughout all redshifts is controversial. The Optically Unbiased GRB Host (TOUGH) survey includes observations of all GRB hosts (69) in an optically unbiased sample of Swift GRBs; we utilize these to constrain the evolution of the UV GRB-host-galaxy luminosity function (LF) between z = 0 and z = 4.5, and compare this with LFs derived from both Lyman-break galaxy (LBG) surveys and simulation modeling. At all redshifts we find the GRB hosts to be most consistent with an LF derived from SFR weighted models incorporating GRB production via both metallicity-dependent and independent channels with a relatively high level of bias toward low metallicity hosts. In the range an SFR weighted LBG derived (i.e., non-metallicity biased) LF is also a reasonable fit to the data. Between z ∼ 3 and z ∼ 6, we observe an apparent lack of UV bright hosts in comparison with LBGs, though the significance of this shortfall is limited by nine hosts of unknown redshift.
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