bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling photometric reverberation mapping data for the next generation of big data surveys. Quasar accretion discs sizes with the LSST
Authors: Pozo Nuñez F , Bruckmann C , Deesamutara S , Czerny B , Panda S , Lobban A P , Pietrzyński G , Polsterer K L 
Published: February 2023

ABSTRACT
Photometric reverberation mapping can detect the radial extent of the accretion disc (AD) in Active Galactic Nuclei by measuring the time delays between light curves observed in different continuum bands. Quantifying the constraints on the efficiency and accuracy of the delay measurements is important for recovering the AD size-luminosity relation, and potentially using quasars as standard candles. We have explored the possibility of determining the AD size of quasars using next-generation Big Data surveys. We focus on the Legacy Survey of Space and Time (LSST) at the Vera C. Rubin Observatory, which will observe several thousand quasars with the Deep Drilling Fields and up to 10 million quasars for the main survey in six broadband filter during its 10-yr operational lifetime. We have developed extensive simulations that take into account the characteristics of the LSST survey and the intrinsic properties of the quasars. The simulations are used to characterize the light curves from which AD sizes are determined using various algorithms. We find that the time delays can be recovered with an accuracy of 5 and 15 per cent for light curves with a time sampling of 2 and 5 d, respectively. The results depend strongly on the redshift of the source and the relative contribution of the emission lines to the bandpasses. Assuming an optically thick and geometrically thin AD, the recovered time-delay spectrum is consistent with black hole masses derived with 30 per cent uncertainty.
The Multi-band Survey Telescope at Zhongshan Station, Antarctica
Authors: Chen Chao , Li Zhengyang , Yang Chenwei , Han Zijian , Jiang Xin , Liu Tingting , Yuan Xiangyan , Jiang Peng , Ji Tuo , Yao Xu , Chen Mingfei 
Published: February 2023

ABSTRACTThe Antarctic Plateau is considered to be the best ground-based astronomical site on Earth. Compared with other middle latitude observatories, the telescopes located in Antarctica have unique advantages in seeing a large fraction of clear nights, continuous observing window in the polar night, and so on. China has operated several generations of telescopes in Antarctica, but has not yet achieved multicolour simultaneous observation with tracking. Multi-band Survey Telescope (MST) is the first multicolour simultaneous survey telescope in Antarctica. It adopts a Newtonian telescope structure which is different from other Antarctic telescopes and is matched with a new alignment scheme suitable for the harsh environment of Antarctica. In addition, MST is equipped with a defrosting indium tin oxide (ITO) window and a high-precision equatorial mount. This paper introduces the optical design, mechanical structure, and analysis of the actual operation of MST in Antarctica. Since March 2022, MST has been carrying out the observation normally in Zhongshan Station, and the operation of MST has provided a new experience for the follow-up design and installation of Antarctic telescopes. We plan to further optimize the design and manufacture of MST, and develop it as a standard model of small-aperture Antarctic telescopes for space debris observations and time-domain surveys.
Simulating the deposition of angular momentum by jets in common envelope evolution
Authors: Schreier Ron , Hillel Shlomi , Soker Noam 
Published: February 2023

ABSTRACT
We conducted 3D hydrodynamical simulations of common envelope evolution (CEE) of a neutron star (NS) or a black hole (BH) inside a red supergiant (RSG) envelope and find that the jets that we expect the NS/BH to launch during the CEE spin-up the common envelope. We find that when the NS/BH launches jets that are exactly perpendicular to the orbital plane (the jets are aligned with the orbital angular momentum) the jets deposit angular momentum to the envelope that is aligned with the orbital angular momentum. When the jets’ axis is inclined to the orbital angular momentum axis, so is the angular momentum that the jets deposit to the envelope. Such tilted jets might be launched when the NS/BH has a close companion when it enters the RSG envelope. We did not allow for spiralling-in and could follow the evolution for only three orbits. The first orbit mimics the plunge-in phase of the CEE, when the NS/BH rapidly dives in, while the third orbit mimics the self-regulated phase when spiralling-in is very slow. We find that the jets deposit significant amount of angular momentum only during the plunge-in phase. A post-CEE core collapse supernova explosion will leave two NS/BH, bound or unbound, whose spin might be misaligned to the orbital angular momentum. Our results strengthen an earlier claim that inclined-triple-star CEE might lead to spin-orbit misalignment of NS/BH-NS/BH binary systems.
Monitoring observations of SMC X-1’s excursions (MOOSE)  – II. A new excursion accompanies spin-up acceleration
Authors: Hu Chin-Ping , Dage Kristen C , Clarkson William I , Brumback McKinley , Charles Philip A , Haggard Daryl , Hickox Ryan C , Mihara Tatehiro , Bahramian Arash , Karam Rawan , Athukoralalage Wasundara , Altamirano Diego , Neilsen Joey , Kennea Jamie 
Published: February 2023

ABSTRACTSMC X-1 is a high-mass X-ray binary showing superorbital modulation with an unstable period. Previous monitoring shows three excursion events in 1996–1998, 2005–2007, and 2014–2016. The superorbital period drifts from ≳60 to ≲40 d and then evolves back during an excursion. Here, we report a new excursion event of SMC X-1 in 2020–2021, indicating that the superorbital modulation has an unpredictable, chaotic nature. We trace the spin-period evolution and find that the spin-up rate accelerated 1 yr before the onset of this new excursion, which suggests a possible inside-out process connecting the spin-up acceleration and the superorbital excursion. This results in a deviation of the spin-period residual, similar to the behaviour of the first excursion in 1996–1998. In further analysis of the pulse profile evolution, we find that the pulsed fraction shows a long-term evolution and may be connected to the superorbital excursion. These discoveries deepen the mystery of SMC X-1 because they cannot be solely interpreted by the warped-disc model. Upcoming pointed observations and theoretical studies may improve our understanding of the detailed accretion mechanisms taking place.
Lognormal seminumerical simulations of the Lyman α forest: comparison with full hydrodynamic simulations
Authors: Arya Bhaskar , Choudhury Tirthankar Roy , Paranjape Aseem , Gaikwad Prakash 
Published: February 2023

ABSTRACTObservations of the Lyman α (Ly α) forest in spectra of distant quasars enable us to probe the matter power spectrum at relatively small scales. With several upcoming surveys, it is expected that there will be a many-fold increase in the quantity and quality of data, and hence it is important to develop efficient simulations to forward model these data sets. One such seminumerical method is based on the assumption that the baryonic densities in the intergalactic medium (IGM) follow a lognormal distribution. In this work, we test the robustness of the lognormal model of the Ly α forest in recovering a set of IGM parameters by comparing with high-resolution Sherwood smoothed particle hydrodynamics (SPH) simulations. We study the recovery of the parameters T0 (temperature of the mean-density IGM), γ (slope of the temperature–density relation), and Γ12 (hydrogen photoionization rate) at z ∼ 2.5 using a Markov chain Monte Carlo technique for parameter estimation. Using three flux statistics, the probability distribution, the mean flux, and the power spectrum, values of all three parameters, T0, γ, and Γ12, implied in the SPH simulations are recovered within 1 − σ (∼9, 4, and 1 per cent, respectively) of the median (best-fitting) values. We verify the validity of our results at different baryon smoothing filter, signal-to-noise ratio, box size and resolution, and data seed and confirm that the lognormal model can be used as an efficient tool for modelling the Ly α transmitted flux at z ∼ 2.5.
Spectroscopy of CASSOWARY gravitationally lensed galaxies in SDSS: characterization of an extremely bright reionization-era analogue at z = 1.42
Authors: Mainali Ramesh , Stark Daniel P , Jones Tucker , Ellis Richard S , Hezaveh Yashar D , Rigby Jane R 
Published: February 2023

ABSTRACT
We present new observations of 16 bright (r = 19–21) gravitationally lensed galaxies at z ≃ 1–3 selected from the CASSOWARY survey. Included in our sample is the z = 1.42 galaxy CSWA-141, one of the brightest known reionization-era analogues at high redshift (g = 20.5), with a large specific star formation rate (31.2 Gyr−1) and an [O iii]+H β equivalent width (EW[O iii] + H β = 730 Å) that is nearly identical to the average value expected at z ≃ 7–8. In this paper, we investigate the rest-frame UV nebular line emission in our sample with the goal of understanding the factors that regulate strong C iii] emission. Although most of the sources in our sample show weak UV line emission, we find elevated C iii] in the spectrum of CSWA-141 (EWC iii] = 4.6 ± 1.9 Å) together with detections of other prominent emission lines (O iii], Si iii], Fe ii⋆, Mg ii). We compare the rest-optical line properties of high-redshift galaxies with strong and weak C iii] emission, and find that systems with the strongest UV line emission tend to have young stellar populations and nebular gas that is moderately metal-poor and highly ionized, consistent with trends seen at low and high redshift. The brightness of CSWA-141 enables detailed investigation of the extreme emission line galaxies which become common at z &gt; 6. We find that gas traced by the C iii] doublet likely probes higher densities than that traced by [O ii] and [S ii]. Characterization of the spectrally resolved Mg ii emission line and several low-ionization absorption lines suggests neutral gas around the young stars is likely optically thin, potentially facilitating the escape of ionizing radiation.
Correcting bandwidth depolarization by extreme Faraday rotation
Authors: Fine Maxwell A , Van Eck Cameron L , Pratley Luke 
Published: February 2023

ABSTRACT
Measurements of the polarization of radio emission are subject to a number of depolarization effects such as bandwidth depolarization, which is caused by the averaging effect of a finite channel bandwidth combined with the frequency-dependent polarization caused by Faraday rotation. There have been very few mathematical treatments of bandwidth depolarization, especially in the context of the rotation measure (RM) synthesis method for analysing radio polarization data. We have found a simple equation for predicting if bandwidth depolarization is significant for a given observational configuration. We have derived and tested three methods of modifying RM synthesis to correct for bandwidth depolarization. From these tests we have developed a new algorithm that can detect bandwidth-depolarized signals with higher signal-to-noise ratio than conventional RM synthesis and recover the correct source polarization properties (RM and polarized intensity). We have verified that this algorithm works as expected with real data from the LOw-Frequency ARray (LOFAR) Two-metre Sky Survey. To make this algorithm available to the community, we have added it as a new tool in the RM-Tools polarization analysis package.
Regulating Big Tech: the role of enhanced disclosures
Authors: Mazzucato Mariana , Strauss Ilan , O’Reilly Tim , Ryan-Collins Josh 
Published: February 2023

Abstract
Attempts by governments to curb the market power of ‘Big Tech’ (Alphabet, Amazon, Apple, Meta Platforms, and Microsoft) are impeded by limited public information on their diversified digital platform ecosystems. Big Tech’s annual 10-K financial reports disclose little about their globally dominant ‘free’ services, platform user numbers, and monetization practices, and suites of products. To support antitrust and regulatory oversight, we propose mandatory 10-K type disclosures covering Big Tech’s: (i) internally used operating metrics (e.g. monthly active users), which underpin platform market share and monetization; (ii) ubiquitous ‘free’ products which escape traditional ‘profit and loss’ reporting; (iii) ‘monetization’ processes detailing how platforms make money from user data and attention; and (iv) product-by-product reporting through updating segment reporting rules. Disclosures should be mandatory for digital ‘gatekeepers’ and eventually integrated into reporting standards for all digital platforms.
Competition, trade, and sustainability in agriculture and food markets in Africa
Authors: Roberts Simon 
Published: February 2023

AbstractFood and agriculture accounts for around one-third of global emissions reflecting the effects of consumption in high-income countries on production and land use around the world. These effects include those transmitted through international trade such as in the constituents of animal feed for meat. African countries face a dual challenge of adapting to the growing effects of climate change in the shape of extreme weather, and increasing agriculture and food production as part of developing their economies. At the same time, there is increasing concentration in the production and trading of agriculture and food products, globally and within Africa. This article considers the interaction of concentration and responses to climate change in food markets through a focus on meat and animal feed, and the developments in maize and soybeans in East and Southern Africa. The possible role for competition policy as part of a wider reform agenda is proposed.
Cross-border data flows and privacy in global trade law: has trade trumped data protection?
Authors: Burri Mira 
Published: February 2023

Abstract
This article is set against the complex backdrop of the evolution of the data-driven economy and its regulation, and seeks to provide a better contextualization of the topic of data protection as a matter of trade law. It looks at the recent proliferation of rules on data flows, specifically addressed in free trade agreements (FTAs), at how data protection has been framed in these treaties, as well as at the available reconciliation mechanisms developed to interface trade and privacy. The article explores the most advanced models that have been developed in this regard so far, with a focus on some US-led and EU-led treaties. These analyses build the basis for testing the conjecture as to whether trade law has gone too fast and too deep, encroaching on domestic privacy law developments that unfold at a much slower pace.
Market power of digital platforms
Authors: Franck Jens-Uwe , Peitz Martin 
Published: February 2023

Abstract
Digital platforms have reshaped many product markets and play an increasingly important role in economies around the globe. Some of these platforms have become powerful players and may possess a lot of market power. Economists use a number of indicators to assess market power. In this article we discuss to which extent these indicators are helpful in the context of digital platforms. In particular, we focus on assessing entrenched market power and the role of potential competition to constrain this power. Finally, we discuss some cross-border issues of platform market power.
Building trust in digital trade will require a rethink of trade policy-making
Authors: Aaronson Susan Ariel 
Published: February 2023

Abstract
In 2019, Shinzo Abe, then Prime Minister of Japan, stated that if the world wanted to achieve the benefits of the data-driven economy, members of the World Trade Organization should find a common approach to combining ‘data free flow with trust’. However, he never explained what these rules should look like and how nations might find an internationally accepted approach to such rules. In this paper, I argue that trade policy-makers must pay closer attention to users’ concerns if they truly want to achieve ‘data free flow with trust’. I begin with an examination of what the most recent digital trade/ecommerce agreements say about trust and discuss whether they actually meet user concerns. Next, I turn to three different examples of online problems that users have expressed concerns about, namely internet shutdowns/censorship, disinformation, and ransomware, describing how these may yield both trade distortions and less trust online. I argue that policy-makers should address these issues if they believe trade agreements should build trust in cross-border data flows. Moreover, I argue how policy-makers respond to user concerns is as important as what they include in trade agreements. Finally, I note that trade negotiators will need to rethink how they involve the broad public in digital trade policy-making, while recognizing that trade policy agreements may not be the best place to address these problems.
International pro-competition regulation of digital platforms: healthy experimentation or dangerous fragmentation?
Authors: Fletcher Amelia 
Published: February 2023

Abstract
The increasing dominance of a small number of ‘big tech’ companies, across a range of critical online markets, has led to growing calls for regulation to promote more competition, and to ensure that market power is not exploited unfairly. New regulatory regimes to this end are now under development in a variety of jurisdictions. While the new German and EU regulatory regimes are the most advanced, there are detailed proposals under discussion in the UK, US, and China, while in South Korea new regulations have been introduced in relation to the specific area of app stores. This article discusses several questions arising in this context. What problem is pro-competition digital platform regulation trying to solve? Why regulation and not competition law? What are the design challenges involved in developing such regulation? What are the risks arising from diverging regulatory approaches to these global issues and how much these risks be mitigated? And what role can trade policy play?
Rock, scissors, paper: How RNA structure informs function
Authors: Assmann Sarah M , Chou Hong-Li , Bevilacqua Philip C 
Published: February 2023

Abstract
RNA can fold back on itself to adopt a wide range of structures. These range from relatively simple hairpins to intricate 3D folds and can be accompanied by regulatory interactions with both metabolites and macromolecules. The last 50 yr have witnessed elucidation of an astonishing array of RNA structures including transfer RNAs, ribozymes, riboswitches, the ribosome, the spliceosome, and most recently entire RNA structuromes. These advances in RNA structural biology have deepened insight into fundamental biological processes including gene editing, transcription, translation, and structure-based detection and response to temperature and other environmental signals. These discoveries reveal that RNA can be relatively static, like a rock; that it can have catalytic functions of cutting bonds, like scissors; and that it can adopt myriad functional shapes, like paper. We relate these extraordinary discoveries in the biology of RNA structure to the plant way of life. We trace plant-specific discovery of ribozymes and riboswitches, alternative splicing, organellar ribosomes, thermometers, whole-transcriptome structuromes and pan-structuromes, and conclude that plants have a special set of RNA structures that confer unique types of gene regulation. We finish with a consideration of future directions for the RNA structure–function field.
Signaling by the EPFL-ERECTA family coordinates female germline specification through the BZR1 family in Arabidopsis
Authors: Cai Hanyang , Huang Youmei , Liu Liping , Zhang Man , Chai Mengnan , Xi Xinpeng , Aslam Mohammad , Wang Lulu , Ma Suzhuo , Su Han , Liu Kaichuang , Tian Yaru , Zhu Wenhui , Qi Jingang , Dresselhaus Thomas , Qin Yuan 
Published: February 2023

Abstract
In most flowering plants, the female germline is initiated in the subepidermal L2 layer of ovule primordia forming a single megaspore mother cell (MMC). How signaling from the L1 (epidermal) layer could contribute to the gene regulatory network (GRN) restricting MMC formation to a single cell is unclear. We show that EPIDERMAL PATTERNING FACTOR-like (EPFL) peptide ligands are expressed in the L1 layer, together with their ERECTA family (ERf) receptor kinases, to control female germline specification in Arabidopsis thaliana. EPFL-ERf dependent signaling restricts multiple subepidermal cells from acquiring MMC-like cell identity by activating the expression of the major brassinosteroid (BR) receptor kinase BRASSINOSTEROID INSENSITIVE 1 and the BR-responsive transcription factor BRASSINOZOLE RESISTANT 1 (BZR1). Additionally, BZR1 coordinates female germline specification by directly activating the expression of a nucleolar GTP-binding protein, NUCLEOSTEMIN-LIKE 1 (NSN1), which is expressed in early-stage ovules excluding the MMC. Mutants defective in this GRN form multiple MMCs resulting in a strong reduction of seed set. In conclusion, we uncovered a ligand/receptor-like kinase-mediated signaling pathway acting upstream and coordinating BR signaling via NSN1 to restrict MMC differentiation to a single subepidermal cell.
Recent progress and clinical applications of advanced biomaterials in cosmetic surgery
Authors: Li Hairui , Xu Xiujuan , Wu Lina , Chen Xi , Akhter Haris , Wang Yixi , Song Ping , Liao Xiaoxia , Zhang Zhenyu , Li Zhengyong , Zhou Changchun , Cen Ying , Ai Hua , Zhang Xingdong 
Published: February 2023

AbstractMaterials of different allogeneic or xenogeneic or autologous origins are widely used as soft-tissue fillers or structural scaffolds in the field of cosmetic surgery, while complications including prosthesis infection, donor site deformity and filler embolization have always been difficult problems for plastic surgeons. The application of novel biomaterials may bring in hopeful solutions for these problems. Recently, some advanced biomaterials, such as regenerative biomaterials can effectively promote the repair of defective tissues, which have been proven to have good therapeutic as well as cosmetic effects in cosmetic surgery. Therefore, biomaterials with active compounds have drawn significant attention for the tissue regeneration of reconstructive and esthetic treatment. Some of these applications have achieved better clinical outcomes than traditional biological materials. This review summarized recent progress and clinical applications of advanced biomaterials in cosmetic surgery.