Palaeoclimate model simulations are an important tool to improve our
understanding of the mechanisms of climate change. These simulations also
provide tests of the ability of models to simulate ...climates very different
to today. Here we present the results from two brand-new simulations using
the latest version of the UK's physical climate model, HadGEM3-GC3.1; they are the
mid-Holocene (∼6 ka) and Last Interglacial (∼127 ka) simulations, both conducted under the auspices of CMIP6/PMIP4. This
is the first time this version of the UK model has been used to conduct
palaeoclimate simulations. These periods are of particular interest to PMIP4
because they represent the two most recent warm periods in Earth history,
where atmospheric concentration of greenhouse gases and continental
configuration are similar to the pre-industrial period but where there were
significant changes to the Earth's orbital configuration, resulting in a
very different seasonal cycle of radiative forcing. Results for these simulations are assessed firstly against the same model's
pre-industrial control simulation (a simulation comparison, to describe and
understand the differences between the pre-industrial – PI – and the two palaeo simulations)
and secondly against previous versions of the same model relative to
newly available proxy data (a model–data comparison, to compare all
available simulations from the same model with proxy data to assess any
improvements due to model advances). The introduction of this newly
available proxy data adds further novelty to this study. Globally, for
metrics such as 1.5 m temperature and surface rainfall, whilst both the
recent palaeoclimate simulations are mostly capturing the expected sign and,
in some places, magnitude of change relative to the pre-industrial, this is
geographically and seasonally dependent. Compared to newly available proxy
data (including sea surface temperature – SST – and rainfall) and also incorporating data from previous
versions of the model shows that the relative accuracy of the simulations
appears to vary according to metric, proxy reconstruction used for
comparison and geographical location. In some instances, such as mean
rainfall in the mid-Holocene, there is a clear and linear improvement,
relative to proxy data, from the oldest to the newest generation of the
model. When zooming into northern Africa, a region known to be problematic
for models in terms of rainfall enhancement, the behaviour of the West
African monsoon in both recent palaeoclimate simulations is consistent with
current understanding, suggesting a wetter monsoon during the mid-Holocene
and (more so) the Last Interglacial, relative to the pre-industrial era.
However, regarding the well-documented “Saharan greening” during the
mid-Holocene, results here suggest that the most recent version of the UK's
physical model is still unable to reproduce the increases suggested by proxy
data, consistent with all other previous models to date.
Abstract
In this paper, we present the long-term optical spectral monitoring of a changing-look active galactic nucleus (AGN), NGC 3516, covering 22 yr (from 1996 to 2018). We explore a variability ...in the broad lines and continuum, finding that the continuum is changing by more than a factor of 2, while the broad lines are varying by more than a factor of 10. The minimum of activity is observed in 2014, when the broad lines almost disappeared. We confirm that NGC 3516 is a changing-look AGN, and the absorption seen in the ultraviolet and X-ray may indicate that there is an obscuring region that is responsible for this. The line profiles are also changing. The mean profiles of the broad Hα and Hβ lines show a shoulder-like structure in the wings, and an enhanced peak, which could indicate a complex broad-line region. The rms profiles of both lines seem to have the same shape and width, of around 4200 km s−1, indicating practically the same kinematics in the Hα and Hβ emitting regions. Measured time-lags between the continuum and Hα and Hβ broad-line variability are ∼15 and 17 d, respectively. In combination with the broad-line width, these measurements allow us to estimate the central black hole mass of NGC 3516. We find that the black hole mass is (4.73 ± 1.40) × 107M⊙ which is in agreement with previous estimates.
Following destabilization of the medial meniscus (DMM), mice develop experimental osteoarthritis (OA) and associated pain behaviors that are dependent on the stage of disease. We aimed to describe ...changes in gene expression in knee-innervating dorsal root ganglia (DRG) after surgery, in order to identify molecular pathways associated with three pre-defined pain phenotypes: “post-surgical pain”, “early-stage OA pain”, and “persistent OA pain”.
We performed DMM or sham surgery in 10-week old male C57BL/6 mice and harvested L3-L5 DRG 4, 8, and 16 weeks after surgery or from age-matched naïve mice (n = 3/group). RNA was extracted and an Affymetrix Mouse Transcriptome Array 1.0 was performed. Three pain phenotypes were defined: “post-surgical pain” (sham and DMM 4-week vs 14-week old naïve), “early OA pain” (DMM 4-week vs sham 4-week), and “persistent OA pain” (DMM 8- and 16-week vs naïve and sham 8- and 16-week). ‘Top hit’ genes were defined as P < 0.001. Pathway analysis (Ingenuity Pathway Analysis) was conducted using differentially expressed genes defined as P < 0.05. In addition, we performed qPCR for Ngf and immunohistochemistry for F4/80+ macrophages in the DRG.
For each phenotype, top hit genes identified a small number of differentially expressed genes, some of which have been previously associated with pain (7/67 for “post-surgical pain”; 2/14 for “early OA pain”; 8/37 for “persistent OA pain”). Overlap between groups was limited, with 8 genes differentially regulated (P < 0.05) in all three phenotypes. Pathway analysis showed that in the persistent OA pain phase many of the functions of differentially regulated genes are related to immune cell recruitment and activation. Genes previously linked to OA pain (CX3CL1, CCL2, TLR1, and NGF) were upregulated in this phenotype and contributed to activation of the neuroinflammation canonical pathway. In separate sets of mice, we confirmed that Ngf was elevated in the DRG 8 weeks after DMM (P = 0.03), and numbers of F4/80+ macrophages were increased 16 weeks after DMM (P = 0.002 vs Sham).
These transcriptomics findings support the idea that distinct molecular pathways discriminate early from persistent OA pain. Pathway analysis suggests neuroimmune interactions in the DRG contribute to initiation and maintenance of pain in OA.
Cytosine DNA methylation is one avenue for passing information through cell divisions. Here, we present epigenomic analyses of soybean recombinant inbred lines (RILs) and their parents. ...Identification of differentially methylated regions (DMRs) revealed that DMRs mostly cosegregated with the genotype from which they were derived, but examples of the uncoupling of genotype and epigenotype were identified. Linkage mapping of methylation states assessed from whole-genome bisulfite sequencing of 83 RILs uncovered widespread evidence for local methylQTL. This epigenomics approach provides a comprehensive study of the patterns and heritability of methylation variants in a complex genetic population over multiple generations, paving the way for understanding how methylation variants contribute to phenotypic variation.
Volcanic eruptions are an important influence on decadal to centennial climate variability. Large eruptions lead to the formation of a stratospheric sulphate aerosol layer which can cause short-term ...global cooling. This response is modulated by feedback processes in the earth system, but the influence from future warming has not been assessed before. Using earth system model simulations we find that the eruption-induced cooling is significantly weaker in the future state. This is predominantly due to an increase in planetary albedo caused by increased tropospheric aerosol loading with a contribution from associated changes in cloud properties. The increased albedo of the troposphere reduces the effective volcanic aerosol radiative forcing. Reduced sea-ice coverage and hence feedbacks also contribute over high-latitudes, and an enhanced winter warming signal emerges in the future eruption ensemble. These findings show that the eruption response is a complex function of the environmental conditions, which has implications for the role of eruptions in climate variability in the future and potentially in the past.
Abstract
We present panchromatic observations and modeling of calcium-strong supernovae (SNe) 2021gno in the star-forming host-galaxy NGC 4165 and 2021inl in the outskirts of elliptical galaxy NGC ...4923, both monitored through the Young Supernova Experiment transient survey. The light curves of both, SNe show two peaks, the former peak being derived from shock cooling emission (SCE) and/or shock interaction with circumstellar material (CSM). The primary peak in SN 2021gno is coincident with luminous, rapidly decaying X-ray emission (
L
x
= 5 × 10
41
erg s
−1
) detected by Swift-XRT at
δ
t
= 1 day after explosion, this observation being the second-ever detection of X-rays from a calcium-strong transient. We interpret the X-ray emission in the context of shock interaction with CSM that extends to
r
< 3 × 10
14
cm. Based on X-ray modeling, we calculate a CSM mass
M
CSM
= (0.3−1.6) × 10
−3
M
⊙
and density
n
= (1−4) × 10
10
cm
−3
. Radio nondetections indicate a low-density environment at larger radii (
r
> 10
16
cm) and mass-loss rate of
M
̇
<
10
−
4
M
⊙
yr
−1
. SCE modeling of both primary light-curve peaks indicates an extended-progenitor envelope mass
M
e
= 0.02−0.05
M
⊙
and radius
R
e
= 30−230
R
⊙
. The explosion properties suggest progenitor systems containing either a low-mass massive star or a white dwarf (WD), the former being unlikely given the lack of local star formation. Furthermore, the environments of both SNe are consistent with low-mass hybrid He/C/O WD + C/O WD mergers.
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•Identification of mercury species in highly polluted brownfields by thermal desorption.•Assessment of Hg fate and bioavailability in old mining-metallurgy sites.•Hg is transported to ...soil and sediments in stable forms, HgS and Hg bound to pyrite.•Methylation can be discarded in these sites.•Utility of thermal desorption technique for parameterizing a remediation treatment.
High contents of mercury (Hg) have been found in old mining-metallurgy sites occurring a widespread contamination and degradation of the land. The ability to identify the Hg species present in these areas is essential to clarify fate of Hg and its bioavailability and additionally, to be able to parameterize remediation techniques based on thermal desorption in order to carry out a full-scale decontamination of the land. This study has proven the usefulness of a thermal programmed desorption procedure (Hg-TPD) for identifying Hg species in contaminated samples related to mining-metallurgy activities. Hg bound to organic matter (Hg-OM) and to pyrite (Hg-FeS2), HgS red, HgCl2, Hg0 and HgO were identified in most of waste samples. The absence of mobile Hg species in soils and sediments showed both its re-emission to the atmosphere (Hg0) or of its oxidation and lixiviation (HgO and HgCl2) over the years. The results have demonstrated that most of these polluted solids can be remediated by thermal treatment at temperatures ranging between 150 and 600°C. The study evidence that Hg-TPD is useful either for parameterizing a thermal remediation or for identifying the evolution pathways of Hg species in different environmental compartments and in general, for any environmental remediation treatment.
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Cystic fibrosis (CF) is a disease characterized by bacterial chronic infection of the respiratory tract and inflammation, which leads to a progressive decrease in lung function. ...Pseudomonas aeruginosa is commonly isolated from the sputum of patients and their presence is associated with a predominant airway inflammation with neutrophils, causing chronic colonization and higher mortality rates. Neutrophil extracellular traps (NETs) have been observed in response against Pseudomonas, however, these cannot eliminate the pathogen from the respiratory tract, so one possibility is that the bacteria could promote their production to use them as a scaffold to colonize the lungs and as a nutrient source, however, their overproduction could also lead to increased damage to the lungs. In this work, we evaluated NETs formation by Pseudomonas clinical isolates obtained from CF patients and found that these induced NETs formation with globular or spread morphologies, of note, we found that there is a trend by which the spread forms were induced mainly by isolates obtained from patients with severe disease, whereas, the globular morphologies were observed for isolates obtained from patients with mild/moderate disease. Finally, we screened for bacterial molecules implicated in NETs formation and found that Exotoxin S, pyocin S2 and pyoverdine could participate in the process.
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