bluuebunny/crossref_metadata_2025_split huggingface dataset:
Focusing of non-linear eccentric waves in astrophysical discs
Authors: Lynch Elliot M , Ogilvie Gordon I 
Published: June 2019

ABSTRACT
We develop a fully non-linear approximation to the short-wavelength limit of eccentric waves in astrophysical discs, based on the averaged Lagrangian method of Whitham. In this limit there is a separation of scales between the rapidly varying eccentric wave and the background disc. Despite having small eccentricities, such rapidly varying waves can be highly non-linear, potentially approaching orbital intersection, and this can result in strong pressure gradients in the disc. We derive conditions for the steepening of non-linearity and eccentricity as the waves propagate in a radially structured disc in this short-wavelength limit and show that the behaviour of the solution can be bounded by the behaviour of the WKB solution to the linearized equations.
Two sub-millimetre bright protoclusters bounding the epoch of peak star-formation activity
Authors: Lacaille Kevin M , Chapman Scott C , Smail Ian , Steidel C C , Blain A W , Geach J , Golob A , Gurwell M , Ivison R J , Reddy N , Sawicki M 
Published: June 2019

ABSTRACT
We present James Clerk Maxwell Telescope Submillimetre Common-User Bolometer Array 2 (SCUBA-2) 850 and 450 $\mu$m observations (σ850 ∼ 0.5 mJy, σ450 ∼ 5 mJy) of the HS1549+19 and HS1700+64 survey fields containing two of the largest known galaxy overdensities at z = 2.85 and 2.30, respectively. We detect 56 sub-millimetre galaxies (SMGs) with SNR &gt; 4 over ∼50 arcmin2 at 850 $\mu$m with flux densities of 3–17 mJy. The number counts indicate overdensities in the 3-arcmin diameter core region (∼1.5 Mpc at z = 2.5) of $6^{+4}_{-2}\times$ (HS1549) and $4^{+6}_{-2}\times$ (HS1700) compared to blank field surveys. Within these core regions, we spectroscopically confirm that approximately one-third of the SMGs lie at the protocluster redshifts for both HS1549 and HS1700. We use statistical identifications of other SMGs in the wider fields to constrain an additional four candidate protocluster members in each system. We combine multiwavelength estimates of the star-formation rates (SFRs) from Lyman-break dropout- and narrow-band-selected galaxies, and the SCUBA-2 SMGs, to estimate total SFRs of 12 500 ± 2800 M⊙ yr−1 (4900 ± 1200 M⊙ yr−1) in HS1549 (HS1700), and SFR densities (SFRDs) within the central 1.5-Mpc diameter of each protocluster to be 3000 ± 900 M⊙ yr−1 Mpc−3 (1300 ± 400 M⊙ yr−1 Mpc−3) in the HS1549 (HS1700) protocluster, ∼104 × larger than the global SFRDs found at their respective epochs, due to the concentration of star-forming galaxies in the small volume of the dense cluster cores. Our results suggest centrally concentrated starbursts within protoclusters may be a relatively common scenario for the build-up of mass in rich clusters assembling at z ≳ 2.
Propane clusters in Titan’s lower atmosphere: insights from a combined theory/laboratory study
Authors: Bourgalais J , Durif O , Le Picard S D , Lavvas P , Calvo F , Klippenstein S J , Biennier L 
Published: June 2019

ABSTRACT
In spite of the considerable advances made by Cassini–Huygens in our understanding of Titan, many questions endure. In particular, the detailed processes that lead to the formation of haze aerosols in Titan’s atmosphere, found in high concentrations at low altitudes, are not well identified. Hydrocarbons, which are abundant constituents of Titan’s cold atmosphere originating from photochemical processes, may simultaneously condense on the surface of existing aerosols, nucleate and grow to generate new aerosol seeds. The relative importance of the various processes depends on several factors, including the saturation ratio. The dynamics of hydrocarbon condensation and nucleation in Titan’s atmosphere remains poorly known. Aiming to progress on these issues, we investigate here the kinetics of propane dimer formation at low temperature through state-of-the-art laboratory experiments combined with theoretical calculations. Our results provide an estimate of the rate coefficients, which are then employed to evaluate the abundance of propane dimers in the lower atmosphere of Titan. The mixing ratios of propane dimers inferred, with a maximum abundance of 10 cm−3 near 100 km, is found to be under the detection limit of the Composite Infrared Spectrometer of the Cassini spacecraft. Based on our results, homogeneous nucleation of the most abundant species appears not to be relevant for the growth of aerosols. Future studies should focus on homogeneous nucleation of polar molecules or alternatively on heterogeneous processes, which are usually more efficient.
Energy occupation of waves and structures in 3D compressive MHD turbulence
Authors: Yang L P , Li H , Li S T , Zhang L , He J S , Feng X S 
Published: June 2019

Abstract
Structures and propagating waves are often observed in solar wind turbulence. Their origins and features remain to be uncovered. In this work, we use 3D driven, compressible MHD turbulence simulations to investigate the global signatures of the driven fluctuations in whole spatial and temporal domain. With four-dimensional spatial-temporal (x, y, z, t) Fourier transformations implemented, we have identified two distinct main populations: waves, which satisfy the $\omega -\boldsymbol {k}$ dispersion relations and are propagating; and structures, which satisfy the polarization relations but non-propagating (ω = 0). Whereas the overall turbulent energy spectrum is still consistent with k−5/3, the contributions from waves and structures show very different behaviour in $\boldsymbol {k}$ space, with structures dominating at small k but waves becomes comparable to structures at large k. Overall, the fluctuations in the directions perpendicular to the large-scale mean field $\boldsymbol {B_0}$ are a manifestation of structures, while along the parallel direction, the fluctuations are dominated by waves. Also, a significant portion of the incompressible structures are the Alfvénic nature, and with imbalanced increased, the waves predominantly propagate in one direction and nearly perpendicular to $\boldsymbol {B_0}$. Differentiating the relative contributions from waves and structures could have important implications for understanding the non-linear cascade processes in the inertial range as well as particle-fluctuation interactions at small scales.
The use of convolutional neural networks for modelling large optically-selected strong galaxy-lens samples
Authors: Pearson James , Li Nan , Dye Simon 
Published: June 2019

ABSTRACTWe explore the effectiveness of deep learning convolutional neural networks (CNNs) for estimating strong gravitational lens mass model parameters. We have investigated a number of practicalities faced when modelling real image data, such as how network performance depends on the inclusion of lens galaxy light, the addition of colour information, and varying signal-to-noise. Our CNN was trained and tested with strong galaxy–galaxy lens images simulated to match the imaging characteristics of the Large Synoptic Survey Telescope (LSST) and Euclid. For images including lens galaxy light, the CNN can recover the lens model parameters with an acceptable accuracy, although a 34 per cent average improvement in accuracy is obtained when lens light is removed. However, the inclusion of colour information can largely compensate for the drop in accuracy resulting from the presence of lens light. While our findings show similar accuracies for single epoch Euclid VIS and LSST r-band data sets, we find a 24 per cent increase in accuracy by adding g- and i-band images to the LSST r-band without lens light and a 20 per cent increase with lens light. The best network performance is obtained when it is trained and tested on images where lens light exactly follows the mass, but when orientation and ellipticity of the light are allowed to differ from those of the mass, the network performs most consistently when trained with a moderate amount of scatter in the difference between the mass and light profiles.
On the nature of variations in the measured star formation efficiency of molecular clouds
Authors: Grudić Michael Y , Hopkins Philip F , Lee Eve J , Murray Norman , Faucher-Giguère Claude-André , Johnson L Clifton 
Published: June 2019

Abstract
Measurements of the star formation efficiency (SFE) of giant molecular clouds (GMCs) in the Milky Way generally show a large scatter, which could be intrinsic or observational. We use magnetohydrodynamic simulations of GMCs (including feedback) to forward-model the relationship between the true GMC SFE and observational proxies. We show that individual GMCs trace broad ranges of observed SFE throughout collapse, star formation, and disruption. Low measured SFEs (${\ll} 1\hbox{ per cent}$) are ‘real’ but correspond to early stages; the true ‘per-freefall’ SFE where most stars actually form can be much larger. Very high (${\gg} 10\hbox{ per cent}$) values are often artificially enhanced by rapid gas dispersal. Simulations including stellar feedback reproduce observed GMC-scale SFEs, but simulations without feedback produce 20× larger SFEs. Radiative feedback dominates among mechanisms simulated. An anticorrelation of SFE with cloud mass is shown to be an observational artefact. We also explore individual dense ‘clumps’ within GMCs and show that (with feedback) their bulk properties agree well with observations. Predicted SFEs within the dense clumps are ∼2× larger than observed, possibly indicating physics other than feedback from massive (main-sequence) stars is needed to regulate their collapse.
Advances and Applications in the Quest for Orthologs
Authors: Glover Natasha , Dessimoz Christophe , Ebersberger Ingo , Forslund Sofia K , Gabaldón Toni , Huerta-Cepas Jaime , Martin Maria-Jesus , Muffato Matthieu , Patricio Mateus , Pereira Cécile , da Silva Alan Sousa , Wang Yan , Sonnhammer Erik , Thomas Paul D 
Published: June 2019

AbstractGene families evolve by the processes of speciation (creating orthologs), gene duplication (paralogs), and horizontal gene transfer (xenologs), in addition to sequence divergence and gene loss. Orthologs in particular play an essential role in comparative genomics and phylogenomic analyses. With the continued sequencing of organisms across the tree of life, the data are available to reconstruct the unique evolutionary histories of tens of thousands of gene families. Accurate reconstruction of these histories, however, is a challenging computational problem, and the focus of the Quest for Orthologs Consortium. We review the recent advances and outstanding challenges in this field, as revealed at a symposium and meeting held at the University of Southern California in 2017. Key advances have been made both at the level of orthology algorithm development and with respect to coordination across the community of algorithm developers and orthology end-users. Applications spanned a broad range, including gene function prediction, phylostratigraphy, genome evolution, and phylogenomics. The meetings highlighted the increasing use of meta-analyses integrating results from multiple different algorithms, and discussed ongoing challenges in orthology inference as well as the next steps toward improvement and integration of orthology resources.
Achieving tight control of a photoactivatable Cre recombinase gene switch: new design strategies and functional characterization in mammalian cells and rodent
Authors: Meador Kyle , Wysoczynski Christina L , Norris Aaron J , Aoto Jason , Bruchas Michael R , Tucker Chandra L 
Published: June 2019

AbstractA common mechanism for inducibly controlling protein function relies on reconstitution of split protein fragments using chemical or light-induced dimerization domains. A protein is split into fragments that are inactive on their own, but can be reconstituted after dimerization. As many split proteins retain affinity for their complementary half, maintaining low activity in the absence of an inducer remains a challenge. Here, we systematically explore methods to achieve tight regulation of inducible proteins that are effective despite variation in protein expression level. We characterize a previously developed split Cre recombinase (PA-Cre2.0) that is reconstituted upon light-induced CRY2-CIB1 dimerization, in cultured cells and in vivo in rodent brain. In culture, PA-Cre2.0 shows low background and high induced activity over a wide range of expression levels, while in vivo the system also shows low background and sensitive response to brief light inputs. The consistent activity stems from fragment compartmentalization that shifts localization toward the cytosol. Extending this work, we exploit nuclear compartmentalization to generate light-and-chemical regulated versions of Cre recombinase. This work demonstrates in vivo functionality of PA-Cre2.0, describes new approaches to achieve tight inducible control of Cre DNA recombinase, and provides general guidelines for further engineering and application of split protein fragments.
Insights into the G-rich VEGF-binding aptamer V7t1: when two G-quadruplexes are better than one!
Authors: Moccia Federica , Riccardi Claudia , Musumeci Domenica , Leone Serena , Oliva Rosario , Petraccone Luigi , Montesarchio Daniela 
Published: June 2019

AbstractThe G-quadruplex-forming VEGF-binding aptamer V7t1 was previously found to be highly polymorphic in a K+-containing solution and, to restrict its conformational preferences to a unique, well-defined form, modified nucleotides (LNA and/or UNA) were inserted in its sequence. We here report an in-depth biophysical characterization of V7t1 in a Na+-rich medium, mimicking the extracellular environment in which VEGF targeting should occur, carried out combining several techniques to analyse the conformational behaviour of the aptamer and its binding to the protein. Our results demonstrate that, in the presence of high Na+ concentrations, V7t1 behaves in a very different way if subjected or not to annealing procedures, as evidenced by native gel electrophoresis, size exclusion chromatography and dynamic light scattering analysis. Indeed, not-annealed V7t1 forms both monomeric and dimeric G-quadruplexes, while the annealed oligonucleotide is a monomeric species. Remarkably, only the dimeric aptamer efficiently binds VEGF, showing higher affinity for the protein compared to the monomeric species. These findings provide new precious information for the development of improved V7t1 analogues, allowing more efficient binding to the cancer-related protein and the design of effective biosensors or theranostic devices based on VEGF targeting.
The Inference to the Best Legal Explanation
Authors: Michelon Claudio 
Published: June 2019

Abstract
Courts use inferences to the best explanation in many contexts and for a variety of purposes. Yet our understanding of lawyers’ uses of this inferential form is insufficient. In this article, after briefly introducing this inferential form, I set out to: (i) explain the structure of such arguments by reference to an argument scheme; (ii) clarify the types of claims courts support by deploying such inferences while attempting to justify acting in accordance with explanatory principles (inferences to the best explanation—principles, or IBE-Ps); (iii) offer an account of the ‘explanatory’ relationship on which IBE-P is predicated; (iv) explain what precisely can count as part of the explanandum in an IBE-P; and (v) discuss criteria that might be used to adjudicate which is the best among rival explanations.
Is the ‘Mere Equity’ to Rescind a Legal Power? Unpacking Hohfeld’s Concept of ‘Volitional Control’
Authors: Reilly Adam 
Published: June 2019

Abstract
Private lawyers owe a particular debt of gratitude to Hohfeld, given their widespread use of his scheme. An example is equitable rescission, where the entitlement to rescind a voidable transfer is now widely understood to be a Hohfeldian legal power. Yet, though scholars have been quick to use Hohfeld’s concept of legal power, they have given little sustained thought to what he meant by ‘volitional control’ and how we might identify it within the law. The result is that certain areas of law have been mislabelled as ‘power conferring’, most notably equitable rescission. This article seeks to unpack Hohfeld’s concept of ‘volitional control’ as terminological shorthand for the coincidence of two distinct elements: (i) the power holder’s normative intention to effect the relevant legal change; and (ii) her decision to effect that change as exhibited in power-exercising conduct. By these lights, the rescinding claimant does not have a legal power to rescind.
Structure-Specific Regulation of Nutrient Transport and Metabolism in Arbuscular Mycorrhizal Fungi
Authors: Kameoka Hiromu , Maeda Taro , Okuma Nao , Kawaguchi Masayoshi 
Published: June 2019

Abstract
Arbuscular mycorrhizal fungi (AMF) establish symbiotic relationships with most land plants, mainly for the purpose of nutrient exchange. Many studies have revealed the regulation of processes in AMF, such as nutrient absorption from soil, metabolism and exchange with host plants, and the genes involved. However, the spatial regulation of the genes within the structures comprising each developmental stage is not well understood. Here, we demonstrate the structure-specific transcriptome of the model AMF species, Rhizophagus irregularis. We performed an ultra-low input RNA-seq analysis, SMART-seq2, comparing five extraradical structures, germ tubes, runner hyphae, branched absorbing structures (BAS), immature spores and mature spores. In addition, we reanalyzed the recently reported RNA-seq data comparing intraradical mycelium and arbuscule. Our analyses captured the distinct features of each structure and revealed the structure-specific expression patterns of genes related to nutrient transport and metabolism. Of note, the transcriptional profiles suggest distinct functions of BAS in nutrient absorption. These findings provide a comprehensive dataset to advance our understanding of the transcriptional dynamics of fungal nutrition in this symbiotic system.
The Impact of Tax and Expenditure Limitations on User Fees and Charges in Local Government Finance: Evidence from New England
Authors: Zhang Pengju , Hou Yilin 
Published: June 2019

AbstractAmerican local government financing shifted from taxation toward user fees and charges (UFCs) in the late 1970s, with substantial efficiency and equity implications. Normatively, the shift aligns with the benefit principle; positively, the shift is often attributed to tax revolts. We test the two associations via a difference-in-differences design and a fiscal stringency measure of tax and expenditure limitations (TELs); we also test the moderating effects of overrides on TELs. Our results confirm that state-imposed TELs caused the shift in local public finance; the results are robust to change of sample and empirical strategy. This article helps explain the relationship between tax revolts and non-tax revenue and provides evidence that fiscal constraints imposed by a higher level government on a constituent level can have significant effects, including effects beyond the intent of the constraints’ framers.
Testing Beta-Pricing Models Using Large Cross-Sections
Authors: Raponi Valentina , Robotti Cesare , Zaffaroni Paolo 
Published: June 2019

Abstract
We propose a methodology for estimating and testing beta-pricing models when a large number of assets is available for investment but the number of time-series observations is fixed. We first consider the case of correctly specified models with constant risk premia, and then extend our framework to deal with time-varying risk premia, potentially misspecified models, firm characteristics, and unbalanced panels. We show that our large cross-sectional framework poses a serious challenge to common empirical findings regarding the validity of beta-pricing models. In the context of pricing models with Fama-French factors, firm characteristics are found to explain a much larger proportion of variation in estimated expected returns than betas.
Authors have furnished an Internet Appendix, which is available on the Oxford University Press Web site next to the link to the final published paper online.
CONE BEAM CT IN DENTAL IMPLANT PLANNING: HOW CLOSE ARE PATIENT DOSIMETRY RESULTS WITH DATA FROM PHANTOM STUDIES FOUND IN LITERATURE?
Authors: Kottou S , Zapros A , Stefanopoulou N , Krompas N , Tsapaki V 
Published: June 2019

Abstract
Advantages of Cone Beam Computed Tomography (CBCT) include high-quality 3D imaging and reduced radiation exposure with relatively low cost. In this study, patient radiation exposure in CBCT implant planning dentistry was measured in terms of Kerma Area Product (KAP). Data were obtained from 217 CBCT scans on 168 individuals using a CS9300 Carestream system. Scans were made using 80–90 kVp, 4–5 mA, 8 and 13.3 s exposure time (depending on voxel size) and a fixed field of view (FOV) of 10 × 10 cm2 (medium). Mean KAP was estimated using two voxel sizes 180 × 180 × 180 μm3 and 200 × 200 × 200 μm3 and found to be 399 and 314 mGycm2, respectively. Corresponding KAP values found in literature ranged between 210 and 2140 mGycm2. Mean E was estimated using conversion coefficient factors found in literature, according to FOV size and tube voltage value and found to range between 24 and 161 μSv.
Single Session Transcranial Magnetic Stimulation Ameliorates Hand Gesture Deficits in Schizophrenia
Authors: Walther Sebastian , Kunz Maribel , Müller Manuela , Zürcher Caroline , Vladimirova Irena , Bachofner Hanta , Scherer Konstantin A , Nadesalingam Niluja , Stegmayer Katharina , Bohlhalter Stephan , Viher Petra V 
Published: June 2019

Abstract
Social interaction is impaired in schizophrenia, including the use of hand gestures, which is linked to poor social perception and outcome. Brain imaging suggests reduced neural activity in a left-lateralized frontoparietal network during gesture preparation; therefore, gesturing might be improved through facilitation of left hemispheric brain areas or via disruption of interhemispheric inhibition from the right homolog. This study tested whether repetitive transcranial magnetic stimulation (rTMS) protocols would improve gesture performance in schizophrenia. This randomized, placebo-controlled, double-blind, crossover trial applied 3 different protocols of rTMS separated by 48 h. Twenty right-handed schizophrenia patients and 20 matched healthy controls received facilitatory intermittent theta burst stimulation (iTBS) over the left inferior frontal gyrus (IFG), inhibitory continuous theta burst stimulation (cTBS) over right inferior parietal lobe (IPL), and placebo over left IPL in randomized order. Primary outcome was change in the test of upper limb apraxia (TULIA), rated from video recordings of hand gesture performance. Secondary outcome was change in manual dexterity using the coin rotation task. Participants improved on both tasks following rTMS compared with baseline. Only patients improved gesture performance following right IPL cTBS compared with placebo (P = .013). The results of the coin rotation parallel those of the TULIA, with improvements following right IPL cTBS in patients (P = .001). Single sessions of cTBS on the right IPL substantially improved both gesture performance accuracy and manual dexterity. The findings point toward an inhibition of interhemispheric rivalry as a potential mechanism of action.