150259 research outputs found
Sort by
Corrigendum: Vascular Access Management After Kidney Transplantation Position Paper on Behalf of the Vascular Access Society and the European Kidney Transplant Association
No full textJWST NIRSpec finds no clear signs of an atmosphere on TOI-1685 b
No full textABSTRACT Determining the prevalence of atmospheres on terrestrial planets is a core objective in exoplanetary science. While M dwarf systems offer a promising opportunity, conclusive observations of terrestrial atmospheres have remained elusive, with many yielding flat transmission spectra. We observe four transits of the hot terrestrial planet TOI-1685 b using James Webb Space Telescope (JWST)’s Near Infrared Spectrograph (NIRSpec) G395H instrument. Combining this with the transit from the previously observed phase curve of the planet with the same instrument, we perform a detailed analysis to determine the possibility of an atmosphere on TOI-1685 b. From our retrievals, the Bayesian evidence favours a simple flat line model, indicating no evidence for an atmosphere on TOI-1685 b, in line with results from the phase curve analysis. Our results show that hydrogen-dominated atmospheres can be confidently ruled out. For heavier, secondary atmospheres we find a lower limit on the mean molecular weight of , at a significance of ~5σ. Pure , , , and atmospheres, or a mixed secondary atmosphere () could explain the data (). However, pure atmospheres may be physically unlikely, and the pure and cases require a high-altitude cloud, which could also be interpreted as a thin cloud-free atmosphere. We discuss the theoretical possibility for different types of atmosphere on this planet, and consider the effects of atmospheric escape and stellar activity on the system. Though we find that TOI-1685 b is likely a bare rock, this study also highlights the challenges of detecting secondary atmospheres on rocky planets with JWST
Refining near-infrared spectroscopy for collagen quantification: A new predictive model for archaeological bone
No full textCollagen is a vital archaeological material, preserving biochemical signatures that provide insights into past environments, diets, and human-animal interactions. However, diagenesis can lead to rapid and inconspicuous collagen degradation. Given the variability in collagen preservation and its significance for analyses such as radiocarbon dating, stable isotope analysis, and ZooMS, researchers have developed prescreening techniques to assess collagen preservation before destructive sampling. Current prescreening approaches, including %N and C:N ratios, typically require sample destruction and access to equipped laboratories. Spectroscopic techniques such as Raman spectroscopy and Fourier Transform Infrared spectroscopy have been explored as alternatives, but they are limited in penetration depth, generalizability (at present at least), and are often still destructive, if minimally. Here, we further develop single-point near-infrared (NIR) spectroscopy as a fully non-destructive, rapid, and field-portable method for prescreening bone for collagen preservation. Unlike FTIR and Raman spectroscopic techniques, NIR light penetrates below the surface of bone, enabling assessment of internal collagen preservation without destructive sample preparation. Using Partial Least Squares Regression (PLSR) and Random Forest (RF) modeling, we trained predictive models on whole bones with known collagen yields and validated the models on an independent archaeological collection. Both PLSR and RF models, when restricted to the 2030–2060 nm range, demonstrate strong and comparable performance while avoiding wavelengths associated with consolidants in our reference library. The models outperform traditional % N-based methods in identifying suitable samples for radiocarbon dating. These models enable the high-throughput screening of large collections of bone, improving sample selection and minimizing unnecessary destructive analysis
Revealing Structural Brain-Cognition Relationships in Children: A Comparison of Morphometric Similarity and INverse Divergence Networks.
No full textThe study of structural brain networks (SBNs) offers critical insights into brain-cognition relationships. However, a comprehensive comparison of these methods in terms of their topological properties, cognitive relevance, and sensitivity to connection density remains lacking. This study compares two types of individual-level SBNs-morphometric similarity networks (MSNs) and morphometric inverse divergence (MIND) networks-by analyzing their associations with cognitive performance using sMRI data from 29 male children. Group- and individual-level analyses were conducted to evaluate differences in hemispheric connectivity, topological features, and their correlations with cognitive performance across different connection densities. In our analyses, a connection density of [Formula: see text] appeared optimal for stabilizing network properties and maximizing cognitive correlations in both MSN and MIND. Moreover, advanced network segregation and integration metrics (such as local efficiency and node versatility, along with their global summaries) demonstrated greater sensitivity to cognitive performance. However, MSNs appeared to provide a more reliable framework, demonstrating more stable associations across connection densities in topological and hemispheric dimensions. Specifically, higher cognitive performance may be linked to stronger left intra-hemispheric connectivity, weaker inter-hemispheric connectivity, and more modular network organization-consistent with established theories of hemispheric specialization and efficient modularity. In contrast, MIND networks exhibit reduced effectiveness and stability across metrics and densities in our data. These preliminary insights enhance our understanding of brain-cognition relationships and provide practical guidelines for parameter selection and metric identification in network-based cognitive analyses
Dual peer effects and cross-stock predictability
No full textThis paper introduces a Peer Index (PI) constructed from economically motivated peer networks that summarizes (i) the strength of a firm’s peers and (ii) the firm’s position within its peer group. PI predicts stock returns and earnings surprises over short and long horizons. Machine-learning models based solely on firm-level characteristics do not subsume PI’s predictive power, supporting the interpretation that it captures genuine cross-stock information. Lag-augmented local projections show that positive PI innovations are followed by higher next-month returns that gradually decay without reversal, consistent with slow diffusion of peer information into prices
A model-independent measurement of the CKM angle γ in the decays B± → [K+K−π+π−]Dh± and B± → [π+π−π+π−]Dh± (h = K, π)
No full text
A
bstract
A model-independent determination of the CKM angle
γ
is presented, using the
B
±
→ [
K
+
K
−
π
+
π
−
]
D
h
±
and
B
±
→ [
π
+
π
−
π
+
π
−
]
D
h
±
decays, with
h
=
K, π
. This measurement is the first phase-space binned study of these decay modes, and uses a sample of proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb
−
1
. The phase-space bins are optimised for sensitivity to
γ
, and in each bin external inputs from the BESIII experiment are used to constrain the charm strong-phase parameters. The result of this binned analysis is
γ
=
53
.
9
−
8.9
+
9.5
°
, where the uncertainty includes both statistical and systematic contributions. Furthermore, when combining with existing phase-space integrated measurements of the same decay modes, a value of
γ
=
52
.
6
−
6.4
+
8.5
°
is obtained, which is one of the most precise determinations of
γ
to date.
</jats:p
Heterochromatin epimutations impose mitochondrial dysfunction to confer antifungal resistance.
No full textAntifungal resistance in pathogenic fungi endanger global health and food supply. Wild-type fission yeast, Schizosaccharomyces pombe, can gain resistance to insults including caffeine and antifungal compounds through reversible epimutations. Resistant epimutants exhibit ectopic histone-H3K9 methylation-dependent heterochromatin islands, repressing underlying genes. Two genes whose heterochromatin island-induced repression causes resistance encode mitochondrial proteins: LYR-domain protein Cup1 and Cox1 translation regulator Ppr4. Genetic mutations, cup1-tt and ppr4Δ, that phenocopy epimutants, cause mitochondrial dysfunction, including respiratory deficiency, poor growth on non-glucose carbon sources, and elevated reactive oxygen species. Transcriptomic analyses indicate cup1-tt and ppr4Δ cells activate Pap1 transcription factor-dependent oxidative stress response and mitonuclear retrograde pathways. Pap1 nuclear localisation and recruitment to promoters of oxidoreductase and membrane transporter genes is increased, causing increased efflux activity. cup1 and ppr4 epimutants likewise show mitochondrial dysfunction phenotypes and increased efflux, explaining how heterochromatin-island epimutations cause drug resistance. Thus, wild-type cells harness epimutations that impose mitochondrial dysfunction to bypass external insults. As mitochondrial dysfunction is linked to antifungal resistance in several fungi, similar epimutations likely contribute to development of resistance in fungal pathogens
A next-generation dual guide CRISPR system for genetic interaction library screening.
No full textPairwise perturbation of gene function using the CRISPR/Cas9 system has potential in screening for genetic interactions and synthetic lethal gene pairs to identify combination therapies for cancer. However, existing dual guide expression systems are cumbersome to clone, often result in a large proportion of undesired guide pairs and have an imbalance of guide expression from the two positions. Here, we demonstrate a next-generation system for dual guide delivery based around a tRNA spacer that allows a single-step cloning strategy, as little as 2% of undesired guide pairs, and highly balanced expression of the two guides. This system allows efficient library-scale screening for hundreds of thousands of genetic interactions using the well-understood Streptococcus pyogenes Cas9 (SpCas9) system. We use this to screen a 100,136 guide pair library in colorectal cancer cells and successfully identify synthetic lethal genetic interactions between paralogs or other known interacting genes, establishing our method for performing efficient large-scale genetic interaction screens. This system is versatile and could be used with most guide RNA vector systems, and for other uses of paired guide delivery, such as improving single gene knockout efficiency or improving guide detection in single cell or optical CRISPR screens
Epigenome-wide analysis identifies DNA methylation signatures associated with the infant pupillary light reflex, a candidate intermediate phenotype for autism.
No full textThe pupillary light reflex (PLR), the automatic constriction of the pupil in response to increased luminance, is a candidate early intermediate phenotype associated with autism, with potential to help understand early neurodevelopmental differences because it is controlled by relatively simple neural circuitry. We conducted epigenome-wide association analyses of PLR onset latency and constriction amplitude at 9, 14, and 24 months, with 51 male infants enriched for familial autism likelihood (~ 80% with a first-degree autistic relative), using buccal DNA collected at 9 months. We identified four epigenome-wide differentially methylated probes (p < 2.4 × 10⁻⁷) significantly associated with PLR latency at 14 and 24 months, and 14- to 24-month developmental change in latency. Probes linked to PLR amplitude were identified at a discovery threshold (p < 5 × 10⁻⁵). Regional analyses revealed multiple differentially methylated regions associated with both latency and amplitude. Associated probes were enriched for neurodevelopmental processes and autism-associated genes, including NR4A2, HNRNPU, and NAV2. While the findings are most directly relevant to male infants in whom PLR variability may be associated with familial autism likelihood, they provide novel evidence that DNAm contributes to early variation in PLR. These insights into the biological underpinnings of this reflex support PLR as an early intermediate phenotype associated with autism
Rapid and late cosmic reionization driven by massive galaxies: a joint analysis of constraints from 21-cm, Lyman line, and CMB data sets
No full textABSTRACT Observations of the Epoch of Reionization have the potential to answer long-standing questions of astrophysical interest regarding the nature of the first luminous sources and their effects on the intergalactic medium (IGM). We present astrophysical constraints from a Neural Density Estimation-Accelerated Bayesian joint analysis of constraints deriving from cosmic microwave background power spectrum measurements from Planck and South Pole Telescope, IGM neutral fraction measurements from Lyman line-based data sets, and 21-cm power spectrum upper limits from Hydrogen Epoch of Reionization Array, LOw Frequency ARray, and the Murchison Widefield Array. In the context of the model employed, the data are found to be consistent with galaxies forming from predominantly atomic-cooled hydrogen gas in dark matter haloes, with masses at 95 per cent credibility () being the dominant galactic population driving reionization. These galaxies reionize the neutral hydrogen in the IGM over a narrow redshift interval ( at 95 per cent credibility), with the mid-point of reionization constrained to . We also obtain a tight constraint on the optical depth to reionization, , disfavouring high- scenarios () proposed to ease Planck–Dark Energy Spectroscopic Instrument tensions. Given the parameter posteriors from our joint analysis, we find that the posterior predictive distribution of the global 21-cm signal is reduced in amplitude and shifted to lower redshifts relative to the model prior. We caution, however, that our inferences are model-dependent. Future work incorporating updated mass-dependent star formation efficiencies in atomic cooling haloes, informed by the latest UV luminosity function constraints from the James Webb Space Telescope, promises to refine these inferences further and enhance our understanding of cosmic reionization