bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functions and prospects of melatonin in plant growth, yield, and quality
Authors: Wang Kaixin , Xing Qufan , Ahammed Golam Jalal , Zhou Jie 
Published: May 2022

Abstract
Melatonin (N-acetyl-5-methoxytryptamine) is an indole molecule widely found in animals and plants. It is well known that melatonin improves plant resistance to various biotic and abiotic stresses due to its potent free radical scavenging ability while being able to modulate plant signaling and response pathways through mostly unknown mechanisms. In recent years, an increasing number of studies have shown that melatonin plays a crucial role in improving crop quality and yield by participating in the regulation of various aspects of plant growth and development. Here, we review the effects of melatonin on plant vegetative growth and reproductive development, and systematically summarize its molecular regulatory network. Moreover, the effective concentrations of exogenously applied melatonin in different crops or at different growth stages of the same crop are analysed. In addition, we compare endogenous phytomelatonin concentrations in various crops and different organs, and evaluate a potential function of phytomelatonin in plant circadian rhythms. The prospects of different approaches in regulating crop yield and quality through exogenous application of appropriate concentrations of melatonin, endogenous modification of phytomelatonin metabolism-related genes, and the use of nanomaterials and other technologies to improve melatonin utilization efficiency are also discussed.
Intrinsic alignments of bulges and discs
Authors: Jagvaral Yesukhei , Singh Sukhdeep , Mandelbaum Rachel 
Published: May 2022

ABSTRACT
Galaxies exhibit coherent alignments with local structure in the Universe. This effect, called intrinsic alignments (IAs), is an important contributor to the systematic uncertainties for wide-field weak lensing surveys. On cosmological distance scales, intrinsic shape alignments have been observed in red galaxies, which are usually bulge-dominated; while blue galaxies, which are mostly disc-dominated, exhibit shape alignments consistent with a null detection. However, disc-dominated galaxies typically consist of two prominent structures: disc and bulge. Since the bulge component has similar properties as elliptical galaxies and is thought to have formed in a similar fashion, naturally one could ask whether the bulge components exhibit similar alignments as ellipticals? In this paper, we investigate how different components of galaxies exhibit IA in the TNG100-1 cosmological hydrodynamical simulation, as well as the dependence of IA on the fraction of stars in rotation-dominated structures at $z$ = 0. The measurements were controlled for mass differences between the samples. We find that the bulges exhibit significantly higher IA signals, with a non-linear alignment model amplitude of $A_I = 2.98^{+0.36}_{-0.37}$ compared to the amplitude for the galaxies as a whole (both components), $A_I = 1.13^{+0.37}_{-0.35}$. The results for bulges are statistically consistent with those for elliptical galaxies, which have $A_I = 3.47^{+0.57}_{-0.57}$. These results highlight the importance of studying galaxy dynamics in order to understand galaxy alignments and their cosmological implications.
Massive black hole mergers with orbital information: predictions from the ASTRID simulation
Authors: Chen Nianyi , Ni Yueying , Holgado A Miguel , Matteo Tiziana Di , Tremmel Michael , DeGraf Colin , Bird Simeon , Croft Rupert , Feng Yu 
Published: May 2022

ABSTRACT
We examine massive black hole (MBH) mergers and their associated gravitational wave signals from the large-volume cosmological simulation Astrid . Astrid includes galaxy formation and black hole models recently updated with an MBH seed population between 3 × 104h−1M⊙ and 3 × 105h−1M⊙ and a sub-grid dynamical friction (DF) model to follow the MBH dynamics down to 1.5 ckpc h−1. We calculate the initial eccentricities of MBH orbits directly from the simulation at kpc-scales, and find orbital eccentricities above 0.7 for most MBH pairs before the numerical merger. After approximating unresolved evolution on scales below ${\sim 200\, \text{pc}}$, we find that the in-simulation DF on large scales accounts for more than half of the total orbital decay time ($\sim 500\, \text{Myr}$) due to DF. The binary hardening time is an order of magnitude longer than the DF time, especially for the seed-mass binaries (MBH &lt; 2Mseed). As a result, only $\lesssim 20{{\rm per \,cent}}$ of seed MBH pairs merge at z &gt; 3 after considering both unresolved DF evolution and binary hardening. These z &gt; 3 seed-mass mergers are hosted in a biased population of galaxies with the highest stellar masses of $\gt 10^9\, {\rm M}_\odot$. With the higher initial eccentricity prediction from Astrid , we estimate an expected merger rate of 0.3−0.7 per year from the z &gt; 3 MBH population. This is a factor of ∼7 higher than the prediction using the circular orbit assumption. The Laser Interferometer Space Antenna events are expected at a similar rate, and comprise $\gtrsim 60\,{\rm{per\,cent}}$ seed-seed mergers, $\sim 30\,{\rm{per\,cent}}$ involving only one seed-mass MBH, and $\sim 10\,{\rm{per\,cent}}$ mergers of non-seed MBHs.
Broad-line region clouds orbiting an AGN sample
Authors: Armijos-Abendaño J , López E , Llerena M , Logan C H A 
Published: May 2022

ABSTRACT
We present a spectral and temporal analysis of XMM–Newton data from a sample of six galaxies (NGC 3783, Mrk 279, Mrk 766, NGC 3227, NGC 7314, and NGC 3516). Using the hardness-ratio curves, we identify time intervals in which clouds are eclipsing the central X-ray source in five of the six sources. We detect three occultations in NGC 3227 and one occultation in NGC 3783, NGC 7314, and NGC 3516, together with the well-known occultations in Mrk 766. We estimate the physical properties of the eclipsing clouds. The derived physical size of the X-ray sources (∼(3–28) × 1013 cm) is less than that of the eclipsing clouds with column densities of ∼1022–1023 cm−2, thus a single cloud may block the X-ray source, leading to notorious temporal variability of the X-ray flux. The eclipsing clouds in Mrk 766, NGC 3227, NGC 7314, and NGC 3516 with distances from the X-ray source of ∼(0.3–3.6) $\times 10^4\, R_\mathrm{ g}$ are moving at Keplerian velocities &gt;1122 km s−1, typical parameters of broad-line region clouds, while the eclipsing cloud in NGC 3783 is likely located in the dusty torus. We also find a good anticorrelation with a slope of −187 ± 62 between the known masses of the supermassive black hole in the centre of the galaxies with the equivalent width (EW) of the 6.4 keV Fe line for the five type 1 Seyfert galaxies of our sample, while the type 2 Seyfert galaxy NGC 7314 shows an average EW value of 100 ± 11 eV inconsistent with the above anticorrelation.
The need for a public forecast of stellar activity to optimize exoplanet radial velocity detections and transmission spectroscopy
Authors: Sairam Lalitha , Triaud Amaury H M J 
Published: May 2022

ABSTRACT
Advances in high-precision spectrographs have paved the way for the search for an Earth analogue orbiting a Sun-like star within its habitable zone. However, the research community remains limited by the presence of stellar noise produced by stellar magnetic activity. These activity phenomena can obscure the detection of Earth-mass exoplanets and can create parasitic signals in transmission spectra. In this paper, we outline the need for a public forecast of stellar activity and produce a proof of principle. Using publicly available spectra we are able to forecast stellar minima several years ahead and reach a typical uncertainty on the timing of these minima of $\pm 0.5~\rm yr$, similar to the precision reached on our own Sun’s magnetic cycle. Furthermore, we use our toy model to show that knowing when to observe can improve the sensitivity of HARPS-North’s Solar telescope to low-mass planets by up to an order of magnitude, and we show that the majority of exoplanets selected for Early Release Science and Guaranteed Time Observations on the James Webb will be observed close or during stellar maxima, incurring a higher risk of stellar contamination. We finish our paper by outlining a number of next steps to create a public forecast usable by teams around the globe, by telescope time allocation committees, and in preparation for spacecraft such as Ariel.
Analysis of the reflection spectra of MAXI J1535-571 in the hard and intermediate states
Authors: Dong Yanting , Liu Zhu , Tuo Youli , Steiner James F , Ge Mingyu , García Javier A , Cao Xinwu 
Published: May 2022

ABSTRACT
We report results on the joint-fit of the NuSTAR and HXMT data for the black hole X-ray binary candidate MAXI J1535-571. The observations were obtained in 2017 when the source evolved through the hard, hard-intermediate, and soft-intermediate states over the rising phase of the outburst. After subtracting continuum components, X-ray reflection signatures are clearly showed in those observations. By modelling the relativistic reflection in detail, we find that the inner radius Rin is relatively stable with Rin ≲ 1.55Rg during the three states, which implies that the inner radius likely extends to the innermost stable circular orbit even in the bright hard state. When adopting Rin = RISCO, the spin parameter is constrained to be $0.985_{-0.004}^{+0.002}$ at 90 per cent confidence (statistical only). The best-fitting results reveal that the inclination of the inner accretion disc is ∼70–74 deg, which notably conflicts with the apparent orientation of the ballistic jet (≤45 deg). In addition, both the photon index and the electron temperature increase during the transition from hard to soft state. It seems that the corona evolves from dense low-temperature in the low/hard state to tenuous high-temperature after the state transition, which indicates that the state transition is accompanied by the evolution of the coronal properties.
Mimicking the halo–galaxy connection using machine learning
Authors: de Santi Natalí S M , Rodrigues Natália V N , Montero-Dorta Antonio D , Abramo L Raul , Tucci Beatriz , Artale M Celeste 
Published: May 2022

ABSTRACTElucidating the connection between the properties of galaxies and the properties of their hosting haloes is a key element in galaxy formation. When the spatial distribution of objects is also taken under consideration, it becomes very relevant for cosmological measurements. In this paper, we use machine-learning techniques to analyse these intricate relations in the IllustrisTNG300 magnetohydrodynamical simulation, predicting baryonic properties from halo properties. We employ four different algorithms: extremely randomized trees, K-nearest neighbours, light gradient boosting machine, and neural networks, along with a unique and powerful combination of the results from all four approaches. Overall, the different algorithms produce consistent results in terms of predicting galaxy properties from a set of input halo properties that include halo mass, concentration, spin, and halo overdensity. For stellar mass, the Pearson correlation coefficient is 0.98, dropping down to 0.7–0.8 for specific star formation rate (sSFR), colour, and size. In addition, we apply, for the first time in this context, an existing data augmentation method, synthetic minority oversampling technique for regression with Gaussian noise (SMOGN), designed to alleviate the problem of imbalanced data sets, showing that it improves the overall shape of the predicted distributions and the scatter in the halo–galaxy relations. We also demonstrate that our predictions are good enough to reproduce the power spectra of multiple galaxy populations, defined in terms of stellar mass, sSFR, colour, and size with high accuracy. Our results align with previous reports suggesting that certain galaxy properties cannot be reproduced using halo features alone.
Effects of stellar-mass primordial black holes on first star formation
Authors: Liu Boyuan , Zhang Saiyang , Bromm Volker 
Published: May 2022

ABSTRACT
We use cosmological hydrodynamic zoom-in simulations and semi-analytical models to study the effects of primordial black holes (PBHs) on first star formation. Our models self-consistently combine two competing effects: initial (isocurvature) perturbations induced by PBHs and BH accretion feedback. Focusing on PBHs with masses $\sim 30\, \rm M_{\odot }$, we find that the standard picture of first star formation in molecular-cooling minihaloes is not changed by PBHs, as the simulated star-forming gas clouds in the central parsec are very similar to those in the $\rm \Lambda CDM$ case when PBHs make up fPBH ∼ 10−4−0.1 of dark matter. With a dynamical friction time-scale of $\sim 2{\!-\!}10\ \rm Myr$ when the central gas density reaches $10^{5}\ \rm cm^{-3}$, it is also unlikely that PBHs can sink into star-forming discs and affect the evolution of protostars, although they may interact with the stars during the main-sequence stage. At larger scales, PBHs tend to shift star formation to more massive haloes and accelerate structure formation. The latter effect is stronger in regions with higher initial overdensities. For fPBH ∼ 10−4−0.01 (allowed by observational constraints), the collapsed mass fraction of haloes hosting Population III stars is similar (within a factor of ∼2 at z ≲ 30) to that in $\rm \Lambda CDM$, implying that the impact of stellar-mass PBHs on the cosmic star formation history at z ≳ 10 is small. We also find that the Lyman–Werner photons from PBH accretion in atomic-cooling haloes may facilitate the formation of direct-collapse BHs.
Exploring compact binary merger host galaxies and environments with zELDA
Authors: Mandhai S , Lamb G P , Tanvir N R , Bray J , Nixon C J , Eyles-Ferris R A J , Levan A J , Gompertz B P 
Published: May 2022

ABSTRACT
Compact binaries such as double neutron stars or a neutron star paired with a black hole, are strong sources of gravitational waves during coalescence and also the likely progenitors of various electromagnetic phenomena, notably short-duration gamma-ray bursts (SGRBs), and kilonovae. In this work, we generate populations of synthetic binaries and place them in galaxies from the large-scale hydrodynamical galaxy evolution simulation, eagle. With our zELDA code, binaries are seeded in proportion to star formation rate, and we follow their evolution to merger using both the bpass and cosmic binary stellar evolution codes. We track their dynamical evolution within their host galaxy potential, to estimate the galactocentric distance at the time of the merger. Finally, we apply observational selection criteria to allow comparison of this model population with the legacy sample of SGRBs. We find a reasonable agreement with the redshift distribution (peaking at 0.5 &lt; z &lt; 1), host morphologies, and projected galactocentric offsets (modal impact parameter ≲10 kpc). Depending on the binary simulation used, we predict $\sim 16\!-\!35{{\ \rm per\ cent}}$ of SGRB events would appear ‘host-less’, i.e. sources that merge with high impact parameters or have hosts fainter than the detection limit (H &gt; 26).
B-mode forecast of CMB-Bhārat
Authors: Adak Debabrata , Sen Aparajita , Basak Soumen , Delabrouille Jacques , Ghosh Tuhin , Rotti Aditya , Martínez-Solaeche Ginés , Souradeep Tarun 
Published: May 2022

ABSTRACT
Exploring Cosmic History and Origin (ECHO), popularly known as ‘CMB-Bh$\overline{a}$rat’, is a space mission that has been proposed to the Indian Space Research Organisation for the scientific exploitation of the cosmic microwave background (CMB) at the next level of precision and accuracy. The quest for the CMB polarization B-mode signals, generated by inflationary gravitational waves in the very early universe, is one of the key scientific goals of its experimental design. This work studies the potential of the proposed ECHO instrumental configuration to detect the target tensor-to-scalar ratio r ∼ 10−3 at 3σ significance level, which covers the predictions of a large class of inflationary models. We investigate the performance of two different component separation pipelines, ${\mathtt {NILC}}$ and ${\mathtt {Commander}}$, for the measurement of r in the presence of different physically motivated models of astrophysical foregrounds. For a simplistic foreground model (only polarized dust and synchrotron), both component separation pipelines can achieve the desired sensitivity of ECHO, i.e. σ(r = 0) ∼ (0.4–0.7) × 10−3. ${\mathtt {NILC}}$ performs better than ${\mathtt {Commander}}$ in terms of bias on recovered r for complex spectral models (power law and curved power law) of the synchrotron emission and complex dust models (dust decorrelation). Assuming 84 per cent delensing, we can achieve an improvement of σ(r = 0) by approximately 50 per cent as compared to the results obtained for the same configuration without any lensing correction.
Growth of disc-like pseudo-bulges in SDSS DR7 since z = 0.1
Authors: Kumar Ankit , Kataria Sandeep Kumar 
Published: May 2022

ABSTRACT
Cosmological simulations predict more classical bulges than their observational counterparts in the local Universe. Here, we quantify evolution of the bulges since z = 0.1 using photometric parameters of nearly 39 000 unbarred disc galaxies from SDSS DR7 which are well represented by two components. We adopted a combination of the Sérsic index and Kormendy relation to separate classical bulges and disc-like pseudo-bulges. We found that the fraction of pseudo-bulges (classical bulges) smoothly increases (decreases) as the Universe gets older. In the history of the Universe, there comes a point (z ≈ 0.016) when classical bulges and pseudo-bulges become equal in number. The fraction of pseudo-bulges rises with increasing bulge to disc half-light radius ratio until Re/Rhlr ≈ 0.6 suggesting that a concentrated disc is the most favourable place for pseudo-bulge formation. The mean ellipticity of pseudo-bulges is always greater than that of classical bulges and it decreases with decreasing redshift, indicating that the bulges tend to be more axisymmetric with evolution. Also, the massive bulges are progressing towards axisymmetry at steeper rate than the low-mass bulges. There is no tight correlation of bulge Sérsic index evolution with other photometric properties of the galaxy. Using the sample of multicomponent fitting of S4G data and N-body galaxy models, we have verified that our results are consistent or even more pronounced with multicomponent fitting and high-resolution photometry.
Inference of cell state transitions and cell fate plasticity from single-cell with MARGARET
Authors: Pandey Kushagra , Zafar Hamim 
Published: May 2022

Abstract
Despite recent advances in inferring cellular dynamics using single-cell RNA-seq data, existing trajectory inference (TI) methods face difficulty in accurately reconstructing the cell-state manifold and cell-fate plasticity for complex topologies. Here, we present MARGARET (https://github.com/Zafar-Lab/Margaret) for inferring single-cell trajectory and fate mapping for diverse dynamic cellular processes. MARGARET reconstructs complex trajectory topologies using a deep unsupervised metric learning and a graph-partitioning approach based on a novel connectivity measure, automatically detects terminal cell states, and generalizes the quantification of fate plasticity for complex topologies. On a diverse benchmark consisting of synthetic and real datasets, MARGARET outperformed state-of-the-art methods in recovering global topology and cell pseudotime ordering. For human hematopoiesis, MARGARET accurately identified all major lineages and associated gene expression trends and helped identify transitional progenitors associated with key branching events. For embryoid body differentiation, MARGARET identified novel transitional populations that were validated by bulk sequencing and functionally characterized different precursor populations in the mesoderm lineage. For colon differentiation, MARGARET characterized the lineage for BEST4/OTOP2 cells and the heterogeneity in goblet cell lineage in the colon under normal and inflamed ulcerative colitis conditions. Finally, we demonstrated that MARGARET can scale to large scRNA-seq datasets consisting of ∼ millions of cells.
RNF4 controls the extent of replication fork reversal to preserve genome stability
Authors: Ding Linli , Luo Yi , Tian Tian , Chen Xu , Yang Yulan , Bu Min , Han Jinhua , Yang Bing , Yan Haiyan , Liu Ting , Wu Mengjie , Zhang Guofei , Xu Yipeng , Zhu Shaoxing , Huen Michael S Y , Mao Genxiang , Huang Jun 
Published: May 2022

Abstract
Replication fork reversal occurs via a two-step process that entails reversal initiation and reversal extension. DNA topoisomerase IIalpha (TOP2A) facilitates extensive fork reversal, on one hand through resolving the topological stress generated by the initial reversal, on the other hand via its role in recruiting the SUMO-targeted DNA translocase PICH to stalled forks in a manner that is dependent on its SUMOylation by the SUMO E3 ligase ZATT. However, how TOP2A activities at stalled forks are precisely regulated remains poorly understood. Here we show that, upon replication stress, the SUMO-targeted ubiquitin E3 ligase RNF4 accumulates at stalled forks and targets SUMOylated TOP2A for ubiquitination and degradation. Downregulation of RNF4 resulted in aberrant activation of the ZATT–TOP2A–PICH complex at stalled forks, which in turn led to excessive reversal and elevated frequencies of fork collapse. These results uncover a previously unidentified regulatory mechanism that regulates TOP2A activities at stalled forks and thus the extent of fork reversal.
Critical roles of mitochondrial fatty acid synthesis in tomato development and environmental response
Authors: Zhou Yuhong , Yu Huiyang , Tang Yaping , Chen Rong , Luo Jinying , Shi Chunmei , Tang Shan , Li Xin , Shen Xinyan , Chen Rongfeng , Zhang Yuyang , Lu Yongen , Ye Zhibiao , Guo Liang , Ouyang Bo 
Published: May 2022

Abstract
Plant mitochondrial fatty acid synthesis (mtFAS) appears to be important in photorespiration based on the reverse genetics research from Arabidopsis (Arabidopsis thaliana) in recent years, but its roles in plant development have not been completely explored. Here, we identified a tomato (Solanum lycopersicum) mutant, fern-like, which displays pleiotropic phenotypes including dwarfism, yellowing, curly leaves, and increased axillary buds. Positional cloning and genetic and heterozygous complementation tests revealed that the underlying gene FERN encodes a 3-hydroxyl-ACP dehydratase enzyme involved in mtFAS. FERN was causally involved in tomato morphogenesis by affecting photorespiration, energy supply, and the homeostasis of reactive oxygen species. Based on lipidome data, FERN and the mtFAS pathway may modulate tomato development by influencing mitochondrial membrane lipid composition and other lipid metabolic pathways. These findings provide important insights into the roles and importance of mtFAS in tomato development.