bluuebunny/crossref_metadata_2025_split huggingface dataset:
Connecting steady emission and very high energy flaring states in blazars: the case of Mrk 421
Authors: Dmytriiev A , Sol H , Zech A 
Published: May 2021

ABSTRACT
Various attempts have been made in the literature at describing the origin and the physical mechanisms behind flaring events in blazars with radiative emission models, but detailed properties of multiwavelength (MWL) light curves still remain difficult to reproduce. We have developed a versatile radiative code, based on a time-dependent treatment of particle acceleration, escape, and radiative cooling, allowing us to test different scenarios to connect the continuous low-state emission self-consistently with that during flaring states. We consider flares as weak perturbations of the quiescent state and apply this description to the 2010 February MWL flare of Mrk 421, the brightest very high energy (VHE) flare ever detected from this archetypal blazar, focusing on interpretations with a minimum number of free parameters. A general criterion is obtained, which disfavours a one-zone model connecting low and high state under our assumptions. A two-zone model combining physically connected acceleration and emission regions yields a satisfactory interpretation of the available time-dependent MWL light curves and spectra of Mrk 421, although certain details remain difficult to reproduce. The two-zone scenario finally proposed for the complex quiescent and flaring VHE emitting region involves both Fermi-I and Fermi-II acceleration mechanisms, respectively, at the origin of the quiescent and flaring emission.
Radio galaxies in galaxy groups: kinematics, scaling relations, and AGN feedback
Authors: Pasini T , Finoguenov A , Brüggen M , Gaspari M , de Gasperin F , Gozaliasl G 
Published: May 2021

ABSTRACT
We investigate the kinematic properties of a large (N = 998) sample of COSMOS spectroscopic galaxy members distributed among 79 groups. We identify the Brightest Group Galaxies (BGGs) and cross-match our data with the VLA-COSMOS Deep survey at 1.4 GHz, classifying our parent sample into radio/non-radio BGGs and radio/non-radio satellites. The radio luminosity distribution spans from $L_R\sim 2\times 10^{21}$ W Hz$^{-1}$ to $L_R\sim 3\times 10^{25}$ W Hz$^{-1}$. A phase–space analysis, performed by comparing the velocity ratio (line-of-sight velocity divided by the group velocity dispersion) with the galaxy-group centre offset, reveals that BGGs (radio and non-radio) are mostly ($\sim$80 per cent) ancient infallers. Furthermore, the strongest ($L_R\gt 10^{23}$ W Hz$^{-1}$) radio galaxies are always found within 0.2$R_{\rm vir}$ from the group centre. Comparing our samples with HORIZON-AGN, we find that the velocities and offsets of simulated galaxies are more similar to radio BGGs than to non-radio BGGs, albeit statistical tests still highlight significant differences between simulated and real objects. We find that radio BGGs are more likely to be hosted in high-mass groups. Finally, we observe correlations between the powers of BGG radio galaxies and the X-ray temperatures, $T_{\rm x}$, and X-ray luminosities, $L_{\rm x}$, of the host groups. This supports the existence of a link between the intragroup medium and the central radio source. The occurrence of powerful radio galaxies at group centres can be explained by Chaotic Cold Accretion, as the AGN can feed from both the galactic and intragroup condensation, leading to the observed positive $L_{\rm R}-T_{\rm x}$ correlation.
Point spread function estimation for wide field small aperture telescopes with deep neural networks and calibration data
Authors: Jia Peng , Wu Xuebo , Li Zhengyang , Li Bo , Wang Weihua , Liu Qiang , Popowicz Adam , Cai Dongmei 
Published: May 2021

ABSTRACT
The point spread function (PSF) reflects states of a telescope and plays an important role in the development of data-processing methods, such as PSF-based astrometry, photometry, and image restoration. However, for wide field small aperture telescopes (WFSATs), estimating PSF in any position of the whole field of view is hard, because aberrations induced by the optical system are quite complex and the signal-to-noise ratio of star images is often too low for PSF estimation. In this paper, we further develop our deep neural network (DNN)-based PSF modelling method and show its applications in PSF estimation. During the telescope alignment and testing stage, our method collects system calibration data through modification of optical elements within engineering tolerances (tilting and decentring). Then, we use these data to train a DNN (Tel–Net). After training, the Tel–Net can estimate PSF in any field of view from several discretely sampled star images. We use both simulated and experimental data to test performance of our method. The results show that the Tel–Net can successfully reconstruct PSFs of WFSATs of any states and in any positions of the field of view (FoV). Its results are significantly more precise than results obtained by the compared classic method – inverse distance weight interpolation. Our method provides foundations for developing deep neural network-based data-processing methods for WFSATs, which require strong prior information of PSFs.
Orbital stability of compact three-planet systems – II: post-instability impact behaviour
Authors: Bartram Peter , Wittig Alexander , Lissauer Jack J , Gavino Sacha , Urrutxua Hodei 
Published: May 2021

ABSTRACT
Recent observational missions have uncovered a significant number of compact multi-exoplanet systems. The tight orbital spacing of these systems has led to much effort being applied to the understanding of their stability; however, a key limitation of the majority of these studies is the termination of simulations as soon as the orbits of two planets cross. In this work we explore the stability of compact, three-planet systems, and continue our simulations all the way to the first collision of planets to yield a better understanding of the lifetime of these systems. We perform over 25 000 integrations of a Sun-like star orbited by three Earth-like secondaries for up to a billion orbits to explore a wide parameter space of initial conditions in both the co-planar and inclined cases, with a focus on the initial orbital spacing. We calculate the probability of collision over time and determine the probability of collision between specific pairs of planets. We find systems that persist for over 108 orbits after an orbital crossing and show how the post-instability survival time of systems depends upon the initial orbital separation, mutual inclination, planetary radius, and the closest encounter experienced. Additionally, we examine the effects of very small changes in the initial positions of the planets upon the time to collision and show the effect that the choice of integrator can have upon simulation results. We generalize our results throughout to show both the behaviour of systems with an inner planet initially located at 1 and 0.25 AU.
Population genetics and conservation of recently discovered springsnails in Arizona
Authors: Lavretsky Philip , Duenez Esmeralda , Sorensen Jeffrey 
Published: May 2021

ABSTRACTEstablishing baseline geographical distributions of extant genetic diversity is increasingly important for future conservation efforts of freshwater species. We analyse the mitochondrial cytochrome c oxidase subunit I (COI) gene to taxonomically characterize 233 samples from recently discovered springsnail populations throughout 17 sites in Arizona, USA. A total of 28 unique COI haplotypes were recovered, with the number of haplotypes ranging from 1 to 4 by population in Arizona. Phylogenetic analyses resulted in haplotypes from 13 of 17 locations in Arizona being successfully identified to species, with five described and three undescribed species in the genus Pyrgulopsis (Hydrobiidae). Future work will require in-depth morphological work to clarify the taxonomic status of these putatively novel species. Importantly, among recovered species, we identified haplotype diversity of the critically endangered Three Forks springsnail, Pyrgulopsis trivialis, in the eastern Gila watershed, which will inform wildlife managers in deciding which source populations to use in reintroduction efforts. We discuss possible causes for observed population structure of Arizona's springsnail populations, with suggestions for the future sampling schemes necessary for the conservation of this uniquely important freshwater mollusc.
RNase H1C collaborates with ssDNA binding proteins WHY1/3 and recombinase RecA1 to fulfill the DNA damage repair in Arabidopsis chloroplasts
Authors: Wang Wenjie , Li Kuan , Yang Zhuo , Hou Quancan , Zhao Wei W , Sun Qianwen 
Published: May 2021

Abstract
Proper repair of damaged DNA is crucial for genetic integrity and organismal survival. As semi-autonomous organelles, plastids have their own genomes whose integrity must be preserved. Several factors have been shown to participate in plastid DNA damage repair; however, the underlying mechanism remains unclear. Here, we elucidate a mechanism of homologous recombination (HR) repair in chloroplasts that involves R-loops. We find that the recombinase RecA1 forms filaments in chloroplasts during HR repair, but aggregates as puncta when RNA:DNA hybrids accumulate. ssDNA-binding proteins WHY1/3 and chloroplast RNase H1 AtRNH1C are recruited to the same genomic sites to promote HR repair. Depletion of AtRNH1C or WHY1/3 significantly suppresses the binding of RNA polymerase to the damaged DNA, thus reducing HR repair and modulating microhomology-mediated double-strand break repair. Furthermore, we show that DNA polymerase IB works with AtRNH1C genetically to complete the DNA damage repair process. This study reveals the positive role of R-loops in facilitating the activities of WHY1/3 and RecA1, which in turn secures HR repair and organellar development.
Motivations and Incentives for Digital Repression
Authors: Feldstein Steven 
Published: May 2021

Abstract
This chapter defines digital repression and describes five principal techniques: surveillance, censorship, social manipulation and disinformation, Internet shutdowns, and targeted persecution against online users. It discusses how leaders confront the “dictator’s digital dilemma” (enabling technological innovation while maintaining political control). It addresses whether digital technology is changing the balance between governments and civil society. It examines why certain states employ digital repression but not others and offers two explanations in this regard. Finally, it explores China’s responsibility for the global spread of digital repression and considers whether external or domestic factors are more relevant drivers of these tactics.
Social Manipulation and Disinformation in the Philippines
Authors: Feldstein Steven 
Published: May 2021

Abstract
This chapter examines how, under President Rodrigo Duterte’s leadership, the Philippines government has implemented a unique method of digital repression to advance its political objectives. It focuses on four issues. First, it discusses what set of political factors and governance trends enabled an illiberal populist like Duterte to get elected in the first place. Second, it describes key drivers of digital repression in the Philippines—focusing on social manipulation and disinformation strategies deployed by Duterte’s administration. Third, it explains how digital repression works in the Philippines, outlining the mix of strategies Duterte employs to advance his political objectives. Fourth, it investigates the extent to which outside actors—such as Facebook or the Chinese government—are responsible for enabling the spread of digital repression in the country.
The Myth of Perfect Fidelity
Authors: Kromhout Melle Jan 
Published: May 2021

Abstract
Chapter 1 gives a brief history of the noise of sound media from the late nineteenth to the late twentieth century, tracing the development of different concepts of noise in dialogue with and reaction to ever more complex and sophisticated technologies. It explores the many ways in which inventors, engineers, producers, and musicians have sought to prevent, reduce, and eliminate this noise. The chapter thereby draws the contours of a myth of perfect fidelity or the idea that reproduced sound can in principle be separated from the noise of the medium and complete similitude between original and copy can be achieved. This myth is illustrated by two examples of noise-related technologies: Dolby analog noise reduction, which actively reduces the noise of sound media, and the counterintuitive practice of “dithering” in digital recording, by means of which small amounts of random noise are introduced to reduce digitization errors.
Prologue
Authors: Çidam Çiğdem 
Published: May 2021

Abstract
Through an interpretive analysis of the surprising refiguration of the iconic May ’68 poster “Beauty is in the Street” in Istanbul during the Gezi Protests of 2013, the Prologue sets the stage for the book by making three closely related points. First, it draws attention to the emancipatory potential of such refigurations of past struggles in the present and highlights the importance of keeping a record of democratic events. Second, it establishes the centrality of 1968 in democratic theory by demonstrating how Negri, Habermas, and Rancière formulated their own unique conceptualizations of democratic action in response to the questions that first emerged in the aftermath of the experience of 1968 and continue to shape current debates. Third, it argues that to rescue contemporary democratic events from their ongoing trivialization, it is necessary to develop an alternative conceptual lens that reveals what other accounts erase, namely the on-the-ground efforts of political actors.
Jürgen Habermas
Authors: Çidam Çiğdem 
Published: May 2021

Abstract
This chapter argues that Jürgen Habermas’s engagement with the debates on the German student movement of 1968 led him to question the common tendency to consider the transience of spontaneous popular action a failure. Habermas’s democratic theory construes the ephemerality of such events as an asset that ensures they remain unrestricted by existing norms. The “wild” and “anarchic” moments of direct citizen action constitute the radical core of deliberative democracy. Yet, even as he emphasizes the democratic moments’ unrestricted quality, Habermas, like Rousseau, is also wary of their unpredictability. In his discussions on civil disobedience, Habermas turns to “constitutional patriotism” as a normative criterion to contain the dangers that emanate from the unpredictability of spontaneous action. In doing so, however, Habermas risks transforming political theory into a disciplinary mechanism whereby the theorist, à la Rousseau, takes on the role of an authority figure charged with guiding democratic action.
Jacques Rancière
Authors: Çidam Çiğdem 
Published: May 2021

Abstract
This chapter demonstrates that Rancière’s journey to democratic theory started in the aftermath of May 1968 with his efforts to overcome the problematic transformation of political theory into “a theory of education.” For Rancière, unpredictability is integral to democratic politics. Thus, in an anti-Rousseauian move, he emphasizes the theatrical aspect of democratic action: taking on a role other than who they are, acting as if they are a part in a given social order in which they have no part, political actors stage their equality, disrupting the existing distribution of the sensible. Rancière’s focus on the moments of disruption, however, opens him to the charge of reducing democratic politics to immediate acts of negation. Insofar as he erases the role of intermediating practices in the stagings of equality, Rancière imposes on his accounts a kind of purity that his own work, with its emphasis on broken, polemical voices, cautions against.
Epilogue
Authors: Çidam Çiğdem 
Published: May 2021

Abstract
The Epilogue concludes the book by emphasizing the importance of keeping a record of the political actors’ hopes and desires in the new ways of being that they staged in democratic moments, without tidying up the tensions and disorderly aspects of those events. While such alternative ways of being do not provide future actors with a blueprint, they call into question the inevitability of the social order as it exists. For this reason, it is politically significant to stand up against the current trivialization of these events, which, perhaps inadvertently, plays into the hands of the powers that be who seek to obliterate the memory of democratic moments. For, remembering the experiences of political actors, who created democratic events against all odds may be the only means to keep alive the emancipatory potential of the past, making it possible for it to become a citable source and an inspiration for future struggles.
The History and Growth of Judicial Review, Volume 1
Authors: Calabresi Steven Gow 
Published: May 2021

Abstract
These two books examine the history and growth of judicial review in the key G-20 constitutional democracies, which include the United States, the United Kingdom, France, Germany, Japan, Italy, India, Canada, Australia, South Korea, Brazil, South Africa, Indonesia, Mexico, and the European Union. Both books look at four different theories, which help to explain the birth of judicial review, and to identify which theories apply best in the various countries discussed. The two books consider not only what gives rise to judicial review originally, but also what causes of judicial review lead it to grow and become more powerful and prominent over time. The positive account of what causes the origins and growth of judicial review in so many very different countries, over such a long period of time, has normative implications for the future of judicial review, of the G-20 nations, and of the European Union. This is first sustained positive account of the origins and growth of judicial review in the G-20 constitutional democracies, and in a few other regimes as well. Volume I discusses the G-20 Nations that are Common Law democracies, as well as Israel, and Volume II discusses the G-20 Nations that are Civil Law democracies, as well as the mixed civil law/common law power of the European Court of Justice and of the European Court of Human Rights.
The Union of India: Umpiring and Rights from Wrongs
Authors: Calabresi Steven Gow 
Published: May 2021

Abstract
This chapter addresses the legal system as well as the origins and growth of judicial review in India. Judicial review originated and grew in India for five reasons. First, the history of Privy Council vertical federalism judicial review umpiring in the British Imperial period habituated Indians to the idea of judicial review of the legality of legislation in the sense of an imperial court reining in errant federal subunits. Second, the Framers of the Indian Constitution of 1950 deliberately decided to borrow the strong kind of judicial review described by Professor Gordon Wood from the U.S. Constitution, as well as borrowing from the United States, the idea of a judicially enforceable Bill of Rights. Third, former Prime Minister Indira Gandhi’s state of emergency, in the 1970s, led all the key players in Indian politics to want judicial review for rights from wrongs reasons. Fourth, judicial review in India has functioned as an umpire between the Union government and the states and among the states and various other entities of the Union of India government. Fifth, the Indian National Congress Party was part of an Ackermanian mass mobilization of people who successfully sought independence and which constitutionalized its charisma by peaceful means.
Seduced by drug discovery
Authors: Cordes Eugene H. 
Published: May 2021

Abstract
The opportunity to see the fruit of scientific work in one’s own lifetime proved a compelling motivation to leave a productive academic career in biochemistry and join the pharmaceutical industry, the Merck Research Laboratories specifically. Beginning with work on benign prostatic hypertrophy, the work became involved with statins, angiotensin-converting enzyme inhibitors, and other areas of drug discovery. Taken from experiences at Merck and elsewhere, eleven adventure stories in drug discovery are presented, ten successes and one notable failure. It is emphasized that most of what scientists start in drug discovery eventually fails, but that pharmaceutical scientists are nonetheless enthusiastic about prospects for success in their work and dedicated to it. The organization of this book is provided.
Proscar and Propecia: the Gary and Jerry show
Authors: Cordes Eugene H. 
Published: May 2021

Abstract
Tracking down the metabolic basis of a remarkable human single-gene genetic disease provided the insight required to discover drugs to prevent prostate gland growth in aging men (benign prostatic hyperplasia, BPH) and prevent hair loss in men (male pattern baldness). Victims of this genetic disease are born with the appearance of females and are recognized as such. However, at puberty, they undergo a transformation and develop the characteristics of males. The underlying genetic defect is a mutation in the gene that codes for the enzyme 5-alpha reductase (5AR), which promotes conversion of testosterone (T) into the more potent male sex hormone dihydrotestosterone (DHT). Lack of sufficient DHT in utero prevents the full expression of male anatomy at birth, an issue that is corrected at the time of puberty when a surge of male sex hormones occurs. These men have a very small prostate gland that never grows, do not lose their hair, and do not get acne. This strongly suggests that DHT is the causative agent of BPH, male pattern baldness, and acne. An inhibitor of 5AR would create the functional equivalent of the genetic defect and would be expected to be effective in shrinking an enlarged prostate gland and slowing or preventing hair loss and acne in men. Finasteride is such an inhibitor and has met expectations. It is marketed as Proscar for BPH and Propecia for male pattern baldness. Finasteride is a teratogen (can cause birth defects) and has not been developed for acne for that reason.
The perils of Primaxin
Authors: Cordes Eugene H. 
Published: May 2021

Abstract
Primaxin is one of the most effective antibiotics introduced into medical practice in the past few decades. It is a single-pill combination of two agents, an unusual β-lactam antibiotic and an inhibitor of an obscure kidney enzyme that abolished the efficacy of the β-lactam in that organ. The initial discovery was a β-lactam antibiotic (think penicillin, amoxicillin) named thienamycin from a fermentation broth. Thienamycin had marvelous antibiotic properties, potent against many microorganisms resistant to earlier β lactams, but was notoriously unstable. Once the unusual structure of thienamycin was unraveled, structural modifications were started. A critical chemical modification resulted in a new agent, imipenem, that retained the antibiotic properties of thienamycin but was stable. A second drug discovery effort resulted in an inhibitor of the kidney enzyme, cilistatin. A combination of the two created Primaxin.