bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nucleolar GTPase Bms1 displaces Ttf1 from RFB-sites to balance progression of rDNA transcription and replication
Authors: Zhu Yanqing , Wang Yong , Tao Boxiang , Han Jinhua , Chen Hong , Zhu Qinfang , Huang Ling , He Yinan , Hong Jian , Li Yunqin , Chen Jun , Huang Jun , Lo Li Jan , Peng Jinrong 
Published: November 2021

Abstract
18S, 5.8S, and 28S ribosomal RNAs (rRNAs) are cotranscribed as a pre-ribosomal RNA (pre-rRNA) from the rDNA by RNA polymerase I whose activity is vigorous during the S-phase, leading to a conflict with rDNA replication. This conflict is resolved partly by replication-fork-barrier (RFB)-sites sequences located downstream of the rDNA and RFB-binding proteins such as Ttf1. However, how Ttf1 is displaced from RFB-sites to allow replication fork progression remains elusive. Here, we reported that loss-of-function of Bms1l, a nucleolar GTPase, upregulates rDNA transcription, causes replication-fork stall, and arrests cell cycle at the S-to-G2 transition; however, the G1-to-S transition is constitutively active characterized by persisting DNA synthesis. Concomitantly, ubf, tif-IA, and taf1b marking rDNA transcription, Chk2, Rad51, and p53 marking DNA-damage response, and Rpa2, PCNA, Fen1, and Ttf1 marking replication fork stall are all highly elevated in bms1l mutants. We found that Bms1 interacts with Ttf1 in addition to Rc1l. Finally, we identified RFB-sites for zebrafish Ttf1 through chromatin immunoprecipitation sequencing and showed that Bms1 disassociates the Ttf1‒RFB complex with its GTPase activity. We propose that Bms1 functions to balance rDNA transcription and replication at the S-phase through interaction with Rcl1 and Ttf1, respectively. TTF1 and Bms1 together might impose an S-phase checkpoint at the rDNA loci.
Read-once refutations in Horn constraint systems: an algorithmic approach
Authors: Subramani K , Wojciechowski Piotr , Sheng Ying 
Published: November 2021

Abstract
In this paper, we discuss exact and parameterized algorithms for the problem of finding a read-once refutation (ROR) in an unsatisfiable Horn constraint system (HCS). Recall that a linear constraint system $\mathbf {A \cdot x \ge b}$ is said to be an HCS if each entry in $\textbf {A}$ belongs to the set $\{0,1,-1\}$ and at most one entry in each row of $\textbf {A}$ is positive. In this paper, we examine the importance of constraints in which more variables have negative coefficients than positive coefficients. In particular, we study the impact of the proportion of these ‘net-negative’ constraints has on the difficulty of finding RORs. There exist several algorithms for checking whether an HCS is feasible. To the best of our knowledge, these algorithms are not certifying, i.e. they do not provide a certificate of infeasibility. Our work is concerned with providing a specialized class of certificates called ‘read-once refutations’. In an ROR, each constraint defining the HCS may be used at most once in the derivation of a refutation. The problem of checking if an HCS has an ROR has been shown to be NP-hard. We analyse the HCS ROR problem from three different algorithmic perspectives, viz., parameterized algorithms, exact exponential algorithms and approximation algorithms. In particular, we show that the HCS ROR problem is fixed-parameter tractable (FPT) with respect to the number of constraints in the system that have more variables with negative coefficient than variables with positive coefficient. Additionally, we show that the HCS ROR problem becomes easy when this parameter is both small and large. We also derive an algorithm that runs in time $O(1.66^{m})$, where $m$ is the number of constraints in the HCS. On the lower-bound side, we derive a lower bound on the algorithmic resources needed for this problem using the Exponential Time Hypothesis. We also establish that the HCS ROR problem does not have a polynomial kernel when the number of constraints with three or more variables in a refutation is used as a parameter. Finally, we show that the problem of approximating the length of the shortest ROR in an HCS is NPO PB-complete1.
7Be in the outburst of the ONe nova V6595 Sgr
Authors: Molaro P , Izzo L , D’Odorico V , Aydi E , Bonifacio P , Cescutti G , Harvey E J , Hernanz M , Selvelli P , della Valle M 
Published: November 2021

ABSTRACT
We report on the search for the 7Be ii isotope in the outbursts of the classical nova V6595 Sgr by means of high-resolution Ultraviolet and Visual Echelle Spectrograph (UVES) observations taken at the European Southern Observatory’s Very Large Telescope in 2021 April, about two weeks after its discovery and under difficult circumstances due to the pandemic. Narrow absorption components with velocities at ∼ −2620 and −2820 km s−1, superposed on broader and shallow absorption, are observed in the outburst spectra for the 7Be ii λλ313.0583, 313.1228 nm doublet resonance lines, as well as in several other elements such as Ca ii, Fe i, Mg i, Na i, H i and Li i. Using the Ca ii K line as a reference element, we infer N(7Be)/N(H) ≈ 7.4 × 10−6, or ≈ 9.8 × 10−6 when the 7Be decay is taken into account. The 7Be abundance is about half of the value most frequently measured in novae. The possible presence of overionization in the layers where 7Be ii is detected is also discussed. Observations taken at the Telescopio Nazionale Galileo in La Palma 91 days after discovery showed prominent emission lines of oxygen and neon, which allow us to classify the nova as ONe type. Therefore, although 7Be is expected to be higher in CO novae, it is found at comparable levels in both nova types.
PHANGS-HST: new methods for star cluster identification in nearby galaxies
Authors: Thilker David A , Whitmore Bradley C , Lee Janice C , Deger Sinan , Chandar Rupali , Larson Kirsten L , Hannon Stephen , Ubeda Leonardo , Dale Daniel A , Glover Simon C O , Grasha Kathryn , Klessen Ralf S , Kruijssen J M Diederik , Rosolowsky Erik , Schruba Andreas , White Richard L , Williams Thomas G 
Published: November 2021

ABSTRACT
We present an innovative and widely applicable approach for the detection and classification of stellar clusters, developed for the PHANGS-HST Treasury Program, an NUV-to-I band imaging campaign of 38 spiral galaxies. Our pipeline first generates a unified master source list for stars and candidate clusters, to enable a self-consistent inventory of all star formation products. To distinguish cluster candidates from stars, we introduce the Multiple Concentration Index (MCI) parameter, and measure inner and outer MCIs to probe morphology in more detail than with a single, standard concentration index (CI). We improve upon cluster candidate selection, jointly basing our criteria on expectations for MCI derived from synthetic cluster populations and existing cluster catalogues, yielding model and semi-empirical selection regions (respectively). Selection purity (confirmed clusters versus candidates, assessed via human-based classification) is high (up to 70 per cent) for moderately luminous sources in the semi-empirical selection region, and somewhat lower overall (outside the region or fainter). The number of candidates rises steeply with decreasing luminosity, but pipeline-integrated Machine Learning (ML) classification prevents this from being problematic. We quantify the performance of our PHANGS-HST methods in comparison to LEGUS for a sample of four galaxies in common to both surveys, finding overall agreement with 50–75 per cent of human verified star clusters appearing in both catalogues, but also subtle differences attributable to specific choices adopted by each project. The PHANGS-HST ML-classified Class 1 or 2 catalogues reach ∼1 mag fainter, ∼2 × lower stellar mass, and are 2−5 × larger in number, than attained in the human classified samples.
The fate of icy pebbles undergoing sublimation in protoplanetary discs
Authors: Spadaccia Stefano , Capelo Holly L , Pommerol Antoine , Schuetz Philipp , Alibert Yann , Ros Katrin , Thomas Nicolas 
Published: November 2021

Abstract
Icy pebbles may play an important role in planet formation close to the water ice line of protoplanetary discs. There, dust coagulation is more efficient and re-condensation of vapor on pebbles may enhance their growth outside the ice line. Previous theoretical studies showed that disruption of icy pebbles due to sublimation increases the growth rate of pebbles inside and outside the ice line, by freeing small silicate particles back in the dust reservoir of the disc. However, since planet accretion is dependent on the Stokes number of the accreting pebbles, the growth of planetesimals could be enhanced downstream of the ice line if pebbles are not disrupting upon sublimation. We developed two experimental models of icy pebbles using different silicate dusts, and we exposed them to low-temperature and low-pressure conditions in a vacuum chamber. Increasing the temperature inside the chamber, we studied the conditions for which pebbles are preserved through sublimation without disrupting. We find that small silicate particles (&lt;50 μm) and a small quantity of ice (around 15 per cent pebble mass) are optimal conditions for preserving pebbles through sublimation. Furthermore, pebbles with coarse dust distribution (100–300 μm) do not disrupt if a small percentage (10–20 per cent mass) of dust grains are smaller than 50 μm. Our findings highlight how sublimation is not necessarily causing disruption, and that pebbles seem to survive fast sublimation processes effectively.
Gamma-rays from reaccelerated cosmic rays in high-velocity clouds colliding with the Galactic disc
Authors: del Valle Maria V 
Published: November 2021

ABSTRACT
High-velocity clouds moving towards the disc will reach the Galactic plane and will inevitably collide with the disc. In these collisions, a system of two shocks is produced, one propagating through the disc and the other develops within the cloud. The shocks produced within the clouds in these interactions have velocities of hundreds of kilometres per second. When these shocks are radiative they may be inefficient in accelerating fresh particles; however, they can reaccelerate and compress Galactic cosmic rays from the background. In this work, we investigate the interactions of Galactic cosmic rays within a shocked high-velocity cloud, when the shock is induced by the collision with the disc. This study is focused in the case of radiative shocks. We aim to establish under which conditions these interactions lead to significant non-thermal emission, especially gamma-rays. We model the interaction of cosmic ray protons and electrons reaccelerated and further energized by compression in shocks within the clouds, under very general assumptions. We also consider secondary electron–positron pairs produced by the cosmic ray protons when colliding with the material of the cloud. We conclude that nearby clouds reaccelerating Galactic cosmic rays in local shocks can produce high-energy radiation that might be detectable with existing and future gamma-ray detectors. The emission produced by electrons and secondary pairs is important at radio wavelengths, and in some cases it may be relevant at hard X-rays. Concerning higher energies, the leptonic contribution to the spectral energy distribution is significant at soft gamma-rays.
Possibility of transporting material from Ceres to NEO region via 8:3 MMR with Jupiter
Authors: Kováčová M , Kornoš L , Matlovič P 
Published: November 2021

ABSTRACT
In this work, we investigate the possibility of transporting material to the NEO region via the 8:3 MMR with Jupiter, potentially even material released from the dwarf planet Ceres. By applying the FLI map method to the 8:3 MMR region in the orbital plane of Ceres, we were able to distinguish between stable and unstable orbits. Subsequently, based on the FLI maps (for mean anomaly M = 60° and also M = 30°), 500 of the most stable and 500 of the most unstable particles were integrated for $15\, \mathrm{Myr}$ for each map. Long-term integration in the case of M = 60° showed that most of the stable particles evolved, in general, in uneventful ways with only 0.8 per cent of particles reaching the limit of q ≤ 1.3 au . However, in the case of M = 30°, a stable evolution was not confirmed. Over 40 per cent of particles reached orbits with q ≤ 1.3 au and numerous particles were ejected to hyperbolic orbits or orbits with a &gt; 100 au. The results for stable particles indicate that short-term FLI maps are more suitable for finding chaotic orbits, than for detecting the stable ones. A rough estimate shows that it is possible for material released from Ceres to get to the region of 8:3 MMR with Jupiter. A long-term integration of unstable particles in both cases showed that transportation of material via 8:3 MMR close to the Earth is possible.
Forming short-period substellar companions in 47 Tucanae – I. Dynamical model and brown dwarf tidal capture rates
Authors: Winter Andrew J , Rosotti Giovanni P , Clarke Cathie , Giersz Mirek 
Published: November 2021

ABSTRACT
Stars in globular clusters formed and evolved in the most extreme environment: high density and low metallicity. If the formation of stars and planets is at all sensitive to environmental conditions, this should therefore be evident in globular clusters. Observations have indicated that hot Jupiters are at least an order of magnitude less prevalent in the central region of the globular cluster 47 Tucanae (Tuc) than in the field. In this work, we explore the claims in the literature for additional consequences for the low-mass stellar initial mass function. Tidal capture, the mechanism that produces X-ray binaries in globular clusters, applies also to brown dwarfs (BDs). This process produces tight stellar–BD binaries that would be detectable by transit surveys. Applying a Monte Carlo dynamical evolution model, we compute the overall BD capture rates. We find that the number of captures is lower than previous estimates. Capture efficiency increases steeply with stellar mass, which means that mass segregation reduces capture efficiency as BDs and low-mass stars occupy the same regions. The result of this effect is that the current constraints on the short-period companion fraction remain marginally consistent with initially equal numbers of BDs and stars. However, our findings suggest that expanding the sample in 47 Tuc or surveying other globular clusters for close substellar companions can yield constraints on the substellar initial mass function in these environments. We estimate the capture rates in other globular clusters and suggest that 47 Tuc remains a promising target for future transit surveys.
ESO 137-002: a large spiral undergoing edge-on ram-pressure stripping with little star formation in the tail
Authors: Laudari Sunil , Jáchym Pavel , Sun Ming , Waldron Will , Chatzikos Marios , Kenney Jeffrey , Luo Rongxin , Nulsen Paul , Sarazin Craig , Combes Françoise , Edge Tim , Voit Mark , Donahue Megan , Cortese Luca 
Published: November 2021

ABSTRACT
Ram pressure stripping (RPS) is an important mechanism for galaxy evolution. In this work, we present results from HST and APEX observations of one RPS galaxy, ESO 137-002 in the closest rich cluster Abell 3627. The galaxy is known to host prominent X-ray and H α tails. The HST data reveal significant features indicative of RPS in the galaxy, including asymmetric distribution of dust in the galaxy, dust filaments, and dust clouds in ablation generally aligned with the direction of ram pressure, and young star clusters immediately upstream of the residual dust clouds that suggest star formation (SF) triggered by RPS. The distribution of the molecular gas is asymmetric in the galaxy, with no CO upstream and abundant CO downstream and in the inner tail region. A total amount of ∼5.5 × 109 M⊙ of molecular gas is detected in the galaxy and its tail. On the other hand, we do not detect any active SF in the X-ray and H α tails of ESO 137-002 with the HST data and place a limit on the SF efficiency in the tail. Hence, if selected by SF behind the galaxy in the optical or UV (e.g. surveys like GASP or using the Galex data), ESO 137-002 will not be considered a ‘jellyfish’ galaxy. Thus, galaxies like ESO 137-002 are important for our comprehensive understanding of RPS galaxies and the evolution of the stripped material. ESO 137-002 also presents a great example of an edge-on galaxy experiencing a nearly edge-on RPS wind.
The nuclear and cytoplasmic activities of RNA polymerase III, and an evolving transcriptome for surveillance
Authors: Kessler Alan C , Maraia Richard J 
Published: November 2021

AbstractA 1969 report that described biochemical and activity properties of the three eukaryotic RNA polymerases revealed Pol III as highly distinguishable, even before its transcripts were identified. Now known to be the most complex, Pol III contains several stably-associated subunits referred to as built-in transcription factors (BITFs) that enable highly efficient RNA synthesis by a unique termination-associated recycling process. In vertebrates, subunit RPC7(α/β) can be of two forms, encoded by POLR3G or POLR3GL, with differential activity. Here we review promoter-dependent transcription by Pol III as an evolutionary perspective of eukaryotic tRNA expression. Pol III also provides nonconventional functions reportedly by promoter-independent transcription, one of which is RNA synthesis from DNA 3′-ends during repair. Another is synthesis of 5′ppp-RNA signaling molecules from cytoplasmic viral DNA in a pathway of interferon activation that is dysfunctional in immunocompromised patients with mutations in Pol III subunits. These unconventional functions are also reviewed, including evidence that link them to the BITF subunits. We also review data on a fraction of the human Pol III transcriptome that evolved to include vault RNAs and snaRs with activities related to differentiation, and in innate immune and tumor surveillance. The Pol III of higher eukaryotes does considerably more than housekeeping.
Within-Person Longitudinal Associations Between Electronic Nicotine Delivery Systems Use and Smoking Cessation Efforts Among US Continuing Adult Cigarette Smokers
Authors: Han Dae-Hee , Lee Shin Hyung , Seo Dong-Chul 
Published: November 2021

Abstract

Objectives
Prior studies that examined the role of electronic nicotine delivery systems (ENDS) use in smoking cessation have shown divergent conclusions. This study examined the time-course of ENDS-associated smoking abstinent behaviors among continuing cigarette smokers who were willing but unable to quit smoking.

Methods
Data were drawn from the four waves of the Population Assessment of Tobacco and Health Study. Of the 1684 smokers who tried to quit smoking completely at Wave 1, a total of 1094 who were continuing smokers until Wave 4 and were not lost to follow-ups comprised the sample. Using generalized linear mixed modeling, we fitted weighted negative binomial regression models to examine within-person associations of ENDS use with quit attempts and number of days abstinent from smoking.

Results
Quit attempt frequency and smoking abstinent days were highest at Wave 1, dropped at Wave 2, and then either increased a little or remained stagnant in later waves. ENDS use to quit smoking was associated with more frequent quit attempts (aIRR = 1.67, 95% CI = 1.42–1.95) and more abstinent days (aIRR = 3.28, 95% CI = 2.43–4.44), and the magnitude of such associations became stronger over time. ENDS use was associated with becoming a nondaily smoker among baseline daily smokers.

Conclusions
ENDS use among continuing smokers may help increase the number of quit attempts and smoking abstinent days. Given that the study sample is continuing smokers who failed in complete smoking cessation, future research would be desirable that evaluates whether such abstinent behaviors sustain and manifest harm reduction with improved health outcomes.

Implications
Smokers increasingly adopt electronic nicotine delivery systems (ENDS) to quit smoking. However, the association of ENDS use with smoking cessation efforts among continuing cigarette smokers who were willing but unable to quit smoking is largely unknown. This study found that quit attempts and smoking abstinent days increased with ENDS use to quit smoking by following up with population-representative continuing smokers. Additionally, this study assessed whether cigarette smokers’ abstinent behaviors vary with their use of ENDS by estimating within-person associations with frequent assessments of both exposures and outcomes in a long-term perspective.
Tonoplast and Peroxisome Targeting of γ-tocopherolN-methyltransferase Homologs Involved in the Synthesis of Monoterpene Indole Alkaloids
Authors: Koudounas Konstantinos , Guirimand Gregory , Hoyos Luisa Fernanda Rojas , Carqueijeiro Ines , Cruz Pamela Lemos , Stander Emily , Kulagina Natalja , Perrin Jennifer , Oudin Audrey , Besseau Sébastien , Lanoue Arnaud , Atehortùa Lucia , St-Pierre Benoit , Giglioli-Guivarc’h Nathalie , Papon Nicolas , O’Connor Sarah E , Courdavault Vincent 
Published: November 2021

AbstractMany plant species from the Apocynaceae, Loganiaceae and Rubiaceae families evolved a specialized metabolism leading to the synthesis of a broad palette of monoterpene indole alkaloids (MIAs). These compounds are believed to constitute a cornerstone of the plant chemical arsenal but above all several MIAs display pharmacological properties that have been exploited for decades by humans to treat various diseases. It is established that MIAs are produced in planta due to complex biosynthetic pathways engaging a multitude of specialized enzymes but also a complex tissue and subcellular organization. In this context, N-methyltransferases (NMTs) represent an important family of enzymes indispensable for MIA biosynthesis but their characterization has always remained challenging. In particular, little is known about the subcellular localization of NMTs in MIA-producing plants. Here, we performed an extensive analysis on the subcellular localization of NMTs from four distinct medicinal plants but also experimentally validated that two putative NMTs from Catharanthus roseus exhibit NMT activity. Apart from providing unprecedented data regarding the targeting of these enzymes in planta, our results point out an additional layer of complexity to the subcellular organization of the MIA biosynthetic pathway by introducing tonoplast and peroxisome as new actors of the final steps of MIA biosynthesis.
Public Health Virtue Ethics
Authors: MacKay Kathryn 
Published: November 2021

Abstract
This paper proposes that public health is the sort of institution that has a role in producing structures of virtue in society. This proposal builds upon work that describes how virtues are structured by the practices of institutions, at the collective or whole-of-society level. This work seeks to fill a gap in public health ethics when it comes to virtues. Mainstay moral theories tend to incorporate some role for virtues, but within public health ethics this role has not been fully articulated. Two recent papers have proposed ways in which the virtues might be incorporated: working from a structural account, Rozier suggests that public health could work to instil virtues, like temperance, in the public in order to achieve its health-related goals; Nihlén Fahlquist suggests that compassion is among three virtues that practitioners of public health should cultivate in order to do their work well. In the end, both accounts recommend incorporating virtues at the level of individuals, among the public and among practitioners. I propose a third kind of role for virtue in public health that focuses on structures. Public health activities take place at the population level, and a public health virtue ethics must also be suitably population-focussed.