ABSTRACT
This work investigates the connection between the cosmic web and the halo distribution through the gravitational potential at the field level. We combine three fields of research, cosmic web ...classification, perturbation theory expansions of the halo bias, and halo (galaxy) mock catalogue making methods. In particular, we use the invariants of the tidal field and the velocity shear tensor as generating functions to reproduce the halo number counts of a reference catalogue from full gravity calculations, populating the dark matter field on a mesh well into the non-linear regime ($3\, h^{-1}\, {\rm Mpc}$ scales). Our results show an unprecedented agreement with the reference power spectrum within 1 per cent up to $k=0.72\, h\, {\rm Mpc}^{-1}$. By analysing the three-point statistics on large scales (configurations of up to $k=0.2\, h\, {\rm Mpc}^{-1}$), we find evidence for non-local bias at the 4.8σ confidence level, being compatible with the reference catalogue. In particular, we find that a detailed description of tidal anisotropic clustering on large scales is crucial to achieve this accuracy at the field level. These findings can be particularly important for the analysis of the next generation of galaxy surveys in mock galaxy production.
Context.
Devising fast and accurate methods of predicting the Lyman-
α
forest at the field level, avoiding the computational burden of running large-volume cosmological hydrodynamic simulations, is ...of fundamental importance to quickly generate the massive set of simulations needed by the state-of-the-art galaxy and Ly
α
forest spectroscopic surveys.
Aims.
We present an improved analytical model to predict the Ly
α
forest at the field level in redshift space from the dark matter field, expanding upon the widely used Fluctuating Gunn-Peterson Approximation (FGPA). Instead of assuming a unique universal relation over the whole considered cosmic volume, we introduce a dependence on the cosmic web environment (knots, filaments, sheets, and voids) in the model, thereby effectively accounting for nonlocal bias. Furthermore, we include a detailed treatment of velocity bias in the redshift space distortion modeling, allowing the velocity bias to be cosmic-web-dependent.
Methods.
We first mapped the dark matter field from real to redshift space through a particle-based relation including velocity bias, depending on the cosmic web classification of the dark matter field in real space. We then formalized an appropriate functional form for our model, building upon the traditional FGPA and including a cutoff and a boosting factor mimicking a threshold and inverse-threshold bias effect, respectively, with model parameters depending on the cosmic web classification in redshift space. Eventually, we fit the coefficients of the model via an efficient Markov chain Monte Carlo scheme.
Results.
We find evidence for a significant difference between the same model parameters in different environments, suggesting that for the investigated setup the simple standard FGPA is not able to adequately predict the Ly
α
forest in the different cosmic web regimes. We reproduce the summary statistics of the reference cosmological hydrodynamic simulation that we use for comparison, yielding an accurate mean transmitted flux, probability distribution function, 3D power spectrum, and bispectrum. In particular, we achieve maximum deviation and average deviation accuracy in the Ly
α
forest 3D power spectrum of ∼3% and ∼0.1% up to
k
∼ 0.4
h
Mpc
−1
, and ∼5% and ∼1.8% up to
k
∼ 1.4
h
Mpc
−1
.
Conclusions.
Our new model outperforms previous analytical efforts to predict the Ly
α
forest at the field level in all the probed summary statistics, and has the potential to become instrumental in the generation of fast accurate mocks for covariance matrices estimation in the context of current and forthcoming Ly
α
forest surveys.
Abstract Background Coronary artery disease (CAD) is the leading cause of mortality among diabetic patients, and the neutrophil-to-lymphocyte ratio (NLR) has recently emerged from among inflammatory ...parameters as a potential indicator of vascular complications and poorer outcome in patients with diabetes. This study aimed to evaluate: 1) the impact of diabetes on NLR; and 2) the role of NLR on the extent of CAD among diabetic patients undergoing coronary angiography. Methods Consecutive patients undergoing coronary angiography were included. Diabetic status and main chemistry parameters were assessed at the time of admission. Significant CAD was defined as at least one vessel with stenosis > 50%, while severe CAD was left main and/or three-vessel disease, as evaluated by quantitative coronary angiography (QCA). Results Diabetes was observed in 1377 of 3756 patients (36.7%); they were older, and displayed higher-risk cardiovascular profile and more complex CAD. Diabetic status was also associated with a significant increase in NLR ( P = 0.004). Among diabetics, higher NLR tertile values were related to ageing ( P < 0.001), dyslipidaemia ( P < 0.001), renal failure ( P < 0.001), body mass index ( P < 0.001), previous percutaneous coronary revascularization ( P = 0.004) and cerebrovascular events ( P = 0.003), acute presentation ( P < 0.001), treatment at admission with beta-blockers/statins/ASA (all P < 0.001), diuretics ( P = 0.01) or clopidogrel ( P = 0.04), platelet count ( P = 0.03), white blood cell count, creatinine, glycaemia and C-reactive protein ( P < 0.001), and inversely related to haemoglobin, triglyceride levels ( P < 0.001) and smoking ( P = 0.03). NLR was associated with multivessel disease ( P < 0.001), degree of stenosis ( P = 0.01), type C lesions ( P = 0.02), coronary calcifications and intracoronary thrombus ( P < 0.001), but inversely with in-stent restenosis ( P = 0.003) and TIMI flow grade ( P = 0.02). Also, NLR was directly related to CAD prevalence ( P < 0.001; adjusted OR 95% CI: 1.62 1.27–2.07, P < 0.001) and CAD severity ( P < 0.001; adjusted OR 95% CI: 1.19 1.00–1.43, P = 0.05). Conclusion NLR is increased among diabetic patients and, in such patients, is independently associated with the prevalence and severity of CAD. Further studies are now needed to confirm present results and to evaluate the underlying pathophysiological mechanisms behind our findings.
ABSTRACT
We study the 3D axis of rotation (3D spin) of 77 H i galaxies from the MIGHTEE-H i Early Science observations, and its relation to the filaments of the cosmic web. For this H i-selected ...sample, the alignment between the spin axis and the closest filament (|cos ψ|) is higher for galaxies closer to the filaments, with 〈|cos ψ|〉 = 0.66 ± 0.04 for galaxies <5 Mpc from their closest filament compared to 〈|cos ψ|〉 = 0.37 ± 0.08 for galaxies at 5 < d < 10 Mpc. We find that galaxies with a low H i-to-stellar mass ratio (log10(MH i/M⋆) < 0.11) are more aligned with their closest filaments, with 〈|cos ψ|〉 = 0.58 ± 0.04; whilst galaxies with (log10(MH i/M⋆) > 0.11) tend to be mis-aligned, with 〈|cos ψ|〉 = 0.44 ± 0.04. We find tentative evidence that the spin axis of H i-selected galaxies tend to be aligned with associated filaments (d < 10 Mpc), but this depends on the gas fractions. Galaxies that have accumulated more stellar mass compared to their gas mass tend towards stronger alignment. Our results suggest that those galaxies that have accrued high gas fraction with respect to their stellar mass may have had their spin axis alignment with the filament disrupted by a recent gas-rich merger, whereas the spin vector for those galaxies in which the neutral gas has not been strongly replenished through a recent merger tend to orientate towards alignment with the filament. We also investigate the spin transition between galaxies with a high H i content and a low H i content at a threshold of $M_{\rm{H\,{\small {I}}}\approx 10^{9.5} \mathrm{ M}_{\odot }$ found in simulations; however, we find no evidence for such a transition with the current data.
In the last decade, the neurovascular effects exerted by endocannabinoids (eCBs) have attracted growing interest, because they hold the promise to open new avenues of therapeutic intervention against ...major causes of death in Western society. Several actions of eCBs are mediated by type-1 (CB₁) or type-2 (CB₂) cannabinoid receptors, yet there is no clear evidence of the presence of these proteins in platelets. To demonstrate that CB₁ and CB₂ are expressed in human platelets, we analyzed their protein level by Western blotting and ELISA, visualized their cellular localization by confocal microscopy, and ascertained their functionality by binding assays. We found that CB₁, and to a lesser extent CB₂, are expressed in highly purified human platelets. Both receptor subtypes were predominantly localized inside the cell, thus explaining why they might remain undetected in preparations of plasma membranes. The identification of authentic CB₁ and CB₂ in human platelets supports the potential exploitation of selective agonists or antagonists of these receptors as novel therapeutics to combat neurovascular disorders. It seems remarkable that some of these substances have been already used in humans to treat disease states.
Background: The endocannabinoid 2‐arachidonoylglycerol (2‐AG) is an endogenous lipid that acts through the activation of G‐protein‐coupled cannabinoid receptors and plays essential roles in many ...physiological contexts. In the cardiovascular system 2‐AG is generated by both activated endothelial cells and platelets, and participates in the regulation of inflammation and thrombosis. Although human platelets actively metabolize endocannabinoids, 2‐AG also binds to platelet surface and leads to cell activation. Objective: To investigate the biological consequence of 2‐AG interactions with human platelets and to clarify the role of cannabinoid receptors. Methods: Gel‐filtered platelets were stimulated with 2‐AG in the presence or absence of various inhibitors. Platelet aggregation and secretion were measured in a lumiaggregometer. Calcium ion movements were measured in FURA‐2 loaded platelets. Thromboxane A2 (TxA2) generation was evaluated as Thromboxane B2 accumulation with a commercial EIA assay. Results: 2‐AG induced platelet shape change, aggregation and secretion with a dose‐dependent mechanism that required engagement of platelet TxA2 receptors. 2‐AG caused also cytosolic calcium increase; however, it was totally dependent on availability of TxA2. Indeed 2‐AG was able to induce a robust generation of TxA2 through the cyclooxygenase pathway. Treatment of platelets with inhibitors of monoacylglycerol lipase and fatty acid amide hydrolase did not affect the activation induced by 2‐AG. Moreover, neither CB1 and CB2 proteins nor CB1/CB2 mRNAs were detected in platelets. Conclusions: 2‐AG can be considered a new physiologic platelet agonist able to induce full platelet activation and aggregation with a non‐CB1/CB2 receptor‐mediated mechanism.
Diacylglycerol (DAG) kinases (Dgk), which phosphorylate DAG to generate phosphatidic acid, act as either positive or negative key regulators of cell signaling. We previously showed that Src mediates ...growth factors-induced activation of Dgk-alpha, whose activity is required for cell motility, proliferation and angiogenesis. Here, we demonstrate that both hepatocytes growth factor (HGF) stimulation and v-Src transformation induce tyrosine phosphorylation of Dgk-alpha on Y335, through a mechanism requiring its proline-rich C-terminal sequence. Moreover, we show that both proline-rich sequence and phosphorylation of Y335 of Dgk-alpha mediate: (i) its enzymatic activation, (ii) its ability to interact respectively with SH3 and SH2 domains of Src, (iii) its recruitment to the membrane. In addition, we show that phosphorylation of Dgk-alpha on Y335 is required for HGF-induced motility, while its constitutive recruitment at the membrane by myristylation is sufficient to trigger spontaneous motility in absence of HGF. Providing the first evidence that tyrosine phosphorylation of Dgk-alpha is required for growth-factors-induced activation and membrane recruitment, these findings underscore its relevance as a rheostat, whose activation is a threshold to elicit growth factors-induced migratory signaling.
The triggering receptor expressed on myeloid cells (TREM)-1 is a recently described molecule, which plays an important role in myeloid cell-activated inflammatory responses. TREM-1 is expressed on ...blood neutrophils and monocytes, and also on alveolar macrophages, thus suggesting a potential role in lung inflammatory responses against infections. To investigate the differential expression of TREM-1 in lung infections, its levels were assessed in bronchoalveolar lavage specimens from patients with community-acquired pneumonia or tuberculosis. TREM-1 was also investigated in patients with interstitial lung diseases, as a model of noninfectious inflammatory disease of the lung. TREM-1 expression was significantly increased in lung neutrophils and in lung macrophages of patients with pneumonia (n=7; 387.9+/-61.4 and 660.5+/-18.3, respectively) compared with patients with pulmonary tuberculosis (n=7; 59.2+/-13.1 and 80.6+/-291.2) and patients with interstitial lung diseases (n=10; 91.8+/-23.3 and 123.9+/-22.8). In contrast, TREM-1 expression on peripheral blood neutrophils was no different among the three groups. In conclusion, these data suggest that triggering receptor expressed on myeloid cells-1 is selectively expressed in the lungs of patients with pneumonia caused by extracellular bacteria and not in patients with tuberculosis, providing a potential marker for differential diagnosis.
The cosmic web from perturbation theory Kitaura, F.-S.; Sinigaglia, F.; Balaguera-Antolínez, A. ...
Astronomy and astrophysics (Berlin),
03/2024, Letnik:
683
Journal Article
Recenzirano
Odprti dostop
Context. Analysing the large-scale structure (LSS) in the Universe with galaxy surveys demands accurate structure formation models. Such models should ideally be fast and have a clear theoretical ...framework in order to rapidly scan a variety of cosmological parameter spaces without requiring large training data sets. Aims. This study aims to extend Lagrangian perturbation theory (LPT), including viscosity and vorticity, to reproduce the cosmic evolution from dark matter N -body calculations at the field level. Methods. We extend LPT to a Eulerian framework, which we dub eALPT. An ultraviolet regularisation through the spherical collapse model provided by Augmented LPT turns out to be crucial at low redshifts. This iterative method enables modelling of the stress tensor and introduces vorticity. The eALPT model has two free parameters apart from the choice of cosmology, redshift snapshots, cosmic volume, and the number of particles. Results. We find that compared to N -body solvers, the cross-correlation of the dark matter distribution increases at k = 1 h Mpc −1 and z = 0 from ∼55% with the Zel’dovich approximation (∼70% with ALPT), to ∼95% with the three-timestep eALPT, and the power spectra show percentage accuracy up to k ≃ 0.3 h Mpc −1 .
We describe here a new method for predicting class II major histocompatibility complex-binding peptides, based on the preferences observed in a systematic series of peptide binding experiments where ...each position in a "minimal" peptide was replaced individually by every amino acid. The DRB1*0401 peptide binding preferences were determined and incorporated into a computer program that looks through sequences for potential epitopes and assigns each a score. These scores correlate well with previously determined T cell epitopes of foreign antigens and endogenous peptides from self proteins. Our findings hold implications for the design of subunit vaccines and in the identification of autoantigenic peptide regions within self proteins.
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