bluuebunny/crossref_metadata_2025_split huggingface dataset:
New constraints on the structure of the nuclear stellar cluster of the Milky Way from star counts and MIR imaging
Authors: Gallego-Cano E. , Schödel R. , Nogueras-Lara F. , Dong H. , Shahzamanian B. , Fritz T. K. , Gallego-Calvente A. T. , Neumayer N. 
Published: December 2019

Context. The Milky Way nuclear star cluster (MWNSC) is a crucial laboratory for studying the galactic nuclei of other galaxies, but its properties have not been determined unambiguously until now.
Aims. We aim to study the size and spatial structure of the MWNSC.
Methods. This study uses data and methods that address potential shortcomings of previous studies on the topic. We use 0.2″ angular resolution Ks data to create a stellar density map in the central 86.4 pc × 21 pc at the Galactic center. We include data from selected adaptive-optics-assisted images obtained for the inner parsecs. In addition, we use Spitzer/IRAC mid-infrared (MIR) images. We model the Galactic bulge and the nuclear stellar disk in order to subtract them from the MWNSC. Finally, we fit a Sérsic model to the MWNSC and investigate its symmetry.
Results. Our results are consistent with previous work. The MWNSC is flattened with an axis ratio of q = 0.71 ± 0.10, an effective radius of Re = (5.1 ± 1.0) pc, and a Sérsic index of n = 2.2 ± 0.7. Its major axis may be tilted out of the Galactic plane by up to −10°. The distribution of the giants brighter than the Red Clump (RC) is found to be significantly flatter than the distribution of the faint stars. We investigate the 3D structure of the central stellar cusp using our results on the MWNSC structure on large scales to constrain the deprojection of the measured stellar surface number density, obtaining a value of the 3D inner power law of γ = 1.38 ± 0.06sys ± 0.01stat.
Conclusions. The MWNSC shares its main properties with other extragalactic NSCs found in spiral galaxies. The differences in the structure between bright giants and RC stars might be related to the existence of not completely mixed populations of different ages. This may hint at recent growth of the MWNSC through star formation or cluster accretion.
Systematic survey of the dynamics of Uranus Trojans
Authors: Zhou Lei , Zhou Li-Yong , Dvorak Rudolf , Li Jian 
Published: December 2019

Context. The discovered Uranus Trojan (UT) 2011 QF99 and several candidate UTs have been reported to be in unstable orbits. This implies that the stability region around the triangular Lagrange points L4 and L5 of Uranus should be very limited.
Aims. In this paper, we aim to locate the stability region for UTs and find out the dynamical mechanisms responsible for the structures in the phase space. The null detection of primordial UTs also needs to be explained.
Methods. Using the spectral number as the stability indicator, we constructed the dynamical maps on the (a0, i0) plane. The proper frequencies of UTs were determined precisely with a frequency analysis method that allows us to depict the resonance web via a semi-analytical method. We simulated radial migration by introducing an artificial force acting on planets to mimic the capture of UTs.
Results. We find two main stability regions: a low-inclination (0° −14°) and a high-inclination regime (32° −59°). There is also an instability strip in each of these regions at 9° and 51°, respectively. These strips are supposed to be related with g − 2g5 + g7 = 0 and ν8 secular resonances. All stability regions are in the tadpole regime and no stable horseshoe orbits exist for UTs. The lack of moderate-inclined UTs is caused by the ν5 and ν7 secular resonances, which could excite the eccentricity of orbits. The fine structures in the dynamical maps are shaped by high-degree secular resonances and secondary resonances. Surprisingly, the libration centre of UTs changes with the initial inclination, and we prove it is related to the quasi 1:2 mean motion resonance (MMR) between Uranus and Neptune. However, this quasi-resonance has an ignorable influence on the long-term stability of UTs in the current planetary configuration. About 36.3% and 0.4% of the pre-formed orbits survive fast and slow migrations with migrating timescales of 1 and 10 Myr, respectively, most of which are in high inclination. Since low-inclined UTs are more likely to survive the age of the solar system, they make up 77% of all such long-life orbits by the end of the migration, making a total fraction up to 4.06 × 10−3 and 9.07 × 10−5 of the original population for fast and slow migrations, respectively. The chaotic capture, just like depletion, results from secondary resonances when Uranus and Neptune cross their mutual MMRs. However, the captured orbits are too hot to survive until today.
Conclusions. About 3.81% UTs are able to survive the age of the solar system, among which 95.5% are on low-inclined orbits with i0 <  7.5°. However, the depletion of planetary migration seems to prevent a large fraction of such orbits, especially for the slow migration model. Based on the widely adopted migration models, a swarm of UTs at the beginning of the smooth outward migration is expected and a fast migration is favoured if any primordial UTs are detected.
Realistic collisional water transport during terrestrial planet formation
Authors: Burger C. , Bazsó Á. , Schäfer C. M. 
Published: December 2019

Context. According to the latest theoretical and isotopic evidence, Earth’s water content originates mainly from today’s asteroid belt region, or at least from the same precursor material. This suggests that water was transported inwards to Earth, and to similar planets in their habitable zone, via (giant) collisions of planetary embryos and planetesimals during the chaotic final phase of planet formation.
Aims. In current dynamical simulations water delivery to terrestrial planets is still studied almost exclusively by assuming oversimplified perfect merging, even though water and other volatiles are particularly prone to collisional transfer and loss. To close this gap we have developed a computational framework to model collisional water transport by direct combination of long-term N-body computations with dedicated 3D smooth particle hydrodynamics (SPH) collision simulations of differentiated, self-gravitating bodies for each event.
Methods. Post-collision water inventories are traced self-consistently in the further dynamical evolution, in accretionary or erosive as well as hit-and-run encounters with two large surviving bodies, where besides collisional losses, water transfer between the encountering bodies has to be considered. This hybrid approach enables us for the first time to trace the full dynamical and collisional evolution of a system of approximately 200 bodies throughout the whole late-stage accretion phase (several hundred Myr). As a first application we choose a Solar System-like architecture with already formed giant planets on either circular or eccentric orbits and a debris disk spanning the whole terrestrial planet region (0.5–4 au).
Results. Including realistic collision treatment leads to considerably different results than simple perfect merging, with lower mass planets and water inventories reduced regularly by a factor of two or more. Due to a combination of collisional losses and a considerably lengthened accretion phase, final water content, especially with giant planets on circular orbits, is strongly reduced to more Earth-like values, and closer to results with eccentric giant planets. Water delivery to potentially habitable planets is dominated by very few decisive collisions, mostly with embryo-sized or larger objects and only rarely with smaller bodies, at least if embryos have formed throughout the whole disk initially. The high frequency of hit-and-run collisions and the differences to predominantly accretionary encounters, such as generally low water (and mass) transfer efficiencies, are a crucial part of water delivery, and of system-wide evolution in general.
Seeds of Life in Space (SOLIS)
Authors: Codella C. , Ceccarelli C. , Bianchi E. , Balucani N. , Podio L. , Caselli P. , Feng S. , Lefloch B. , López-Sepulcre A. , Neri R. , Spezzano S. , De Simone M. 
Published: December 2019

Context.It is nowadays clear that a rich organic chemistry takes place in protostellar regions. However, the processes responsible for it, that is, the dominant formation routes to interstellar complex organic molecules, are still a source of debate. Two paradigms have been evoked: the formation of these molecules on interstellar dust mantles and their formation in the gas phase from simpler species previously synthesised on the dust mantles.Aims.In the past, observations of protostellar shocks have been used to set constraints on the formation route of formamide (NH2CHO), exploiting its observed spatial distribution and comparison with astrochemical model predictions. In this work, we follow the same strategy to study the case of acetaldehyde (CH3CHO).Methods.To this end, we used the data obtained with the IRAM-NOEMA interferometer in the framework of the Large Program SOLIS to image the B0 and B1 shocks along the L1157 blueshifted outflow in methanol (CH3OH) and acetaldehyde line emission.Results.We imaged six CH3OH and eight CH3CHO lines which cover upper-level energies up to ~30 K. Both species trace the B0 molecular cavity as well as the northern B1 portion, that is, the regions where the youngest shocks (~1000 yr) occurred. The CH3OH and CH3CHO emission peaks towards the B1b clump, where we measured the following column densities and relative abundances: 1.3 × 1016cm−2and 6.5 × 10−6(methanol), and 7 × 1013cm−2and 3.5 × 10−8(acetaldehyde). We carried out a non-LTE (non-Local Thermodinamic Equilibrium) Large Velocity Gradient (LVG) analysis of the observed CH3OH line: the average kinetic temperature and density of the emitting gas areTkin~ 90 K andnH2~ 4 × 105cm−3, respectively. The CH3OH and CH3CHO abundance ratio towards B1b is 190, varying by less than a factor three throughout the whole B0–B1 structure.Conclusions.Comparison of astrochemical model predictions with the observed methanol and acetaldehyde spatial distribution does not allow us to distinguish whether acetaldehyde is formed on the grain mantles or in the gas phase, as its gas-phase formation, which is dominated by the reaction of ethyl radical (CH3CH2) with atomic oxygen, is very fast. Observations of acetaldehyde in younger shocks, for example those of ~102yr old, and/or of the ethyl radical, whose frequencies are not presently available, are necessary to settle the issue.
High reddening patches in Gaia DR2
Authors: Beitia-Antero Leire , Gómez de Castro Ana Inés , de la Fuente Marcos Raúl 
Published: December 2019

Context. Deep GALEX UV data show that the extreme outskirts of some spiral galaxies are teeming with star formation. Such young stellar populations evolving so far away from the bulk of their host galaxies challenge our overall understanding of how star formation proceeds at galactic scales. It is at present unclear whether our own Milky Way may also exhibit ongoing and recent star formation beyond the conventional edge of the disk (∼15 kpc).
Aims. Using Gaia DR2 data, we aim to determine if such a population is present in the Galactic halo, beyond the nominal radius of the Milky Way disk.
Methods. We studied the kinematics of Gaia DR2 sources with parallax values between 1/60 and 1/30 milliarcseconds towards two regions that show abnormally high values of extinction and reddening; the results are compared with predictions from GALAXIA Galactic model. We also plotted the color–magnitude (CM) diagrams with heliocentric distances computed inverting the parallaxes, and studied the effects of the large parallax errors by Monte Carlo sampling.
Results. The kinematics point towards a Galactic origin for one of the regions, while the provenance of the stars in the other is not clear. A spectroscopic analysis of some of the sources in the first region confirms that they are located in the halo. The CM diagram of the sources suggests that some of them are young.
Current Trends in Practice of Residents in the Saudi Board of Endodontics Program
Authors: AlRahabi Mothanna K. , AlKady Ayman M. 
Published: December 2019

Abstract
Objectives The purpose of the current study was to collect information about some techniques and armamentarium currently used by the Saudi Board of Endodontics residents in relation to the technical steps of root canal therapy.
Materials and Methods A web-based survey was sent to the Saudi Board of Endodontics residents, based in the western area of Saudi Arabia. The survey assessed controversial concepts, and collected information regarding new instruments and materials, used in the technical steps of nonsurgical root canal treatment. A one-sample chi-square test, with a 95% level of significance, was applied to determine whether there were significant differences between respondents’ answers.
Results A total of 45 out of 50 residents (90%) responded to the questionnaire. The majority of Saudi Board residents of Endodontics, who participated in this survey, used the mean of working length (ML) measured by periapical X-Ray and apex locator in the presence of a radiographic lesion (63.3%), and maintained apical patency in all cases (80.0%). ProTaper Universal (40%) and ProTaper Next (41.2%) were the most common NiTi rotary systems used for root canal instrumentation. Thirty percent of respondents used adjunct device with irrigation, and 80% advocated smear layer removal. Zinc oxide–eugenol-based sealers were the most common used sealers (70%), and most residents (86.6%) did not advocate sealer extrusion.
Conclusions This study revealed that residents of the Saudi Board of Endodontics program adopt new endodontic technologies. There is, however, a need for more investigations regarding this objective, including responses from all residents in Saudi Arabia.
A Case of Giant Cell Tumour of Bone in a Dog
Authors: Blondel Margaux , Gros Lucile , Semin Marie-Odile , Delverdier Maxence , Palierne Sophie , Autefage André 
Published: December 2019

Abstract
Case Description A 9-year-old neutered female mixed-breed dog was presented for the assessment of right pelvic limb lameness of 1-week duration. The lameness had progressed to non-weight bearing the day before presentation.
Diagnostic Findings Radiographic examination of the right stifle joint revealed a large purely lytic lesion affecting the proximal metaphysis and epiphysis of the right tibia associated with a pathological fracture of the tibial plateau. These findings, combined with histological evaluation of a bone biopsy performed under ultrasound-guidance, were suggestive of a giant cell tumour of bone.
Treatment and Outcome A limb-sparing procedure was attempted as first-line treatment. Curettage of the tumour was followed by coblation, and the defect was filled with polymethyl methacrylate bone cement. Physical and radiographic follow-up examinations 1, 2 and 3 months after surgery revealed improved functional outcome and minor progression of osteolysis. However, local recurrence was apparent 5 months after initial surgery and the limb was therefore amputated.
Clinical Relevance Giant cell tumour of bone is rare in dogs. In humans, the traditional surgical management is curettage. This treatment was attempted here for the first time in a dog and the short-term outcome was satisfactory. However, in this particular case, local control of the tumour was unsuccessful.
Inhibition of stress corrosion cracking in 304 stainless steel through titanium ion implantation
Authors: Liu Ming , Li ChenYu , Liu Lin , Ye Youjun , Dastan Davoud , Garmestani Hamid 
Published: December 2019

The effects of titanium ion implantation on the stress corrosion cracking (SCC) behaviour of 304 austenitic stainless steel were studied. Slow strain rate tests (SSRTs) were conducted on 304 steel in air and in 5 wt-% NaCl solution. The microscopic effects of ion implantation were evaluated by Stopping and Range of Ions in Matter Procedures (SRIM). Fracture morphologies and microstructures were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The fracture surfaces illustrate that ion implantation significantly inhibits the corrosion pits that initiate SCC. A dense passive film, which inhibits SCC, was formed during the ion implantation process. SCC initiation was restrained due to the dense dislocation nets that were generated by titanium ion implantation. Highlights Ion implantation inhibits SCC susceptibility. The lack of Cr at the grain boundary leads to the expansion of SCC along the grain boundary. Implantation-induced damage leads to high-density dislocations. The surface was amorphised due to high-density dislocations.
Application of Multi-variable Grey Model Method in Power Load Forecasting
Authors: Tong Linghua 
Published: December 2019

Abstract
Electric power has become one of the most important energy sources in today’s society. It is of great significance for power grid enterprises and people’s livelihood to accurately grasp the historical data of power load and to mine the potential value of data. In this paper, by making using of the multi-variable grey model, the power load forecasting is studied. Firstly, this paper establishes the multi-variable grey model with grey system theory. Secondly, the correlation between four temperature factors and load is analyzed, which shows that four temperature factors should be considered as the influencing factors of load. Finally, multi-variable grey model is applied to forecast the summer load of some region in Ningbo. The results show that the prediction has better fitting and prediction accuracy.
A High-Speed Serial Digital Interface Video Signal Jitter Measurement Method
Authors: Li Difei , Chen He , Gao Hongying , Zhao Kejia , Wu Zhaochun , Li Bo 
Published: December 2019

Abstract
This paper designs a measurement method for high-speed serial digital interface video signal jitter. Firstly, we introduce the features of SDI signal and the jitter measurement methods of traditional high-speed serial signals. A jitter model is built for the SDI signal while the properties of the components are analysed. An adjusted dual-Dirac model is adopted to measure the jitter in the signal. This method can accurately analyse different jitter components in SDI signals. It is directly performed on oscilloscope, which is beneficial to the traceability of the jitter. The feasibility of the method is verified by experiments. The measurement results show that the method has better measurement accuracy than the direct spectrum method.
Analysis risk of dynamic stability of power network with multiple small motor groups equivalent to each other
Authors: Yang Lei , Xiang Chuan , He Xin , Xing Chao , Xi Xinze , Sheng Shixian , Xiao Can , Liao Jiasi 
Published: December 2019

Abstract
The BPA data of the regional power grid is usually only used for the detailed modeling of the 110kV grid connected substation, and the 35kV and the following grid station generally use the equivalent parameters of the equivalent capacity of the unit, and then be incorporated into the 110kV power grid for simulation analysis. In order to analyze the accuracy of power system stability simulation after equivalence, a detailed model of the grid connected small hydropower units with 35kV and the following is built. The results show that, using a plurality of small hydropower units group area grid equivalence, dynamic stability analysis of differences, there are regional power grid internal oscillation mode equivalent and cannot reflect the regional oscillation modes in small turbine.
Method of determining vehicle speed according to video stream data
Authors: Murashov I , Stroganov Y 
Published: December 2019

Abstract
This article presents a method of determining the speed of a dynamic object from the data of a video stream. The determination of speed occurs based on the analysis of repeated objects of the environment, the distance between which varies according to a previously known law, such as lamp posts, milestones or bump stops on roads, intermittent road marking lines, emergency exits in tunnels. The method of determining vehicle speed includes three steps: pre-processing of the frame, searching for a pattern in the image, calculating the average vehicle speed obtained on the basis of the number of repeated objects, taking into account the law of their repetition and the distance between them for some fixed time. The advantage of the proposed method is that there is no need to install any additional sensors on the dynamic object except video camera. The development of an additional method for calculating speed has a significant application value for the complexes of control of autonomous traffic, as the existing methods of determining speed have their disadvantages (not high enough accuracy, the requirement for the presence of additional equipment). This algorithm was studied on regularly recurring objects (lampposts) under different lighting conditions (day, night), the distance between repeated objects and different weather conditions. It was also compared with other methods of determining the speed of the data from the video stream, the results of which the proposed method has a significant advantage in accuracy as compared with analogs in the absence of interference with video.
Decision support system for an early-stage keratoconus diagnosis
Authors: Salem B R , Solodovnikov V I 
Published: December 2019

Abstract
Currently, there is a wide variety of different diseases that exist, a lot of which can be hardly prompt diagnosed even by medical specialists. This paper presents a method for early-stage diagnosis of ophthalmologic disorder keratoconus. Working with medical imagery that was captured by a rotating Scheimpflug camera system for anterior segment analysis, the goal was to create a decision support system to aid ophthalmologists in prompt detection of the disorder to eliminate the chance of further surgical intervention. Given approach uses several steps to achieve that goal, such as find the region of interest on the medical imagery using a Single Shot MultiBox Detector, filter and binarize the image, locate the cornea and approximate the curve with least squares fitting, classify the stage according to the previously labeled dataset by medical specialists with a random forest method. The suggested approach achieves 76% precision on a dataset containing 500 images of the patients with the first stage of keratoconus and healthy patients. The final result was compared with modern existing medical methods that are usually used in ophthalmologic clinics by medical specialists.