bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new least squares adjustment approach for the determination of linear meteor trajectories
Authors: Margonis A. , Malissiovas G. , Neitzel F. , Oberst J. 
Published: April 2022

Context.Precise astrometric measurements performed on meteor images are required to derive the dynamical parameters of a mete-oroid. As a consequence, the measurements carried out in this initial step will have a strong impact on the dynamical solution of an orbiting meteoroid. These measurements relate to the position of the meteor defined by the positions of pixels along its path, as well as by their uncertainties. Therefore, the use of all available information is of great importance for the subsequent processing steps.Aims.This paper examines a new geometrical approach for computing the trajectory of a meteor from multi-station observations. The model considers a more general weighting scheme based on existing stochastic information from the measurements, including the geometry between each station and the observed meteor.Methods.We present a novel mathematical model for least squares adjustment of the linear meteor trajectories within the Gauss-Helmert model, which allows the use of stochastic information from the measured direction vectors from multiple stations. Additionally, an extended stochastic model is presented that takes into account the geometric relationship between each station and the observed meteor as a weight component for each group of observations.Results.The solution of the new approach is demonstrated on a synthetic meteor example, with observations generated from multiple stations with differing precision. The geometric configuration of the stations has been chosen in such a way that it creates the necessity to include stochastic information for the observed direction vectors for a realistic solution. The results of the newly developed approach are compared with those from established methods in the literature. Future investigations and optimisations for developing an even more improved meteor trajectory model are being addressed.
Ca II triplet spectroscopy of Small Magellanic Cloud red giants
Authors: Parisi M. C. , Gramajo L. V. , Geisler D. , Dias B. , Clariá J. J. , Da Costa G. , Grebel E. K. 
Published: April 2022

Aims. We aim to analyze the chemical evolution of the Small Magellanic Cloud, adding 12 additional clusters to our existing sample, based on accurate and homogeneously derived metallicities. We are particularly interested in seeing if there is any correlation between age and metallicity for the different structural components to which the clusters belong, taking into account their positions relative to the different tidal structures present in the galaxy.
Methods. The spectroscopic metallicities of red giant stars were derived from the measurement of the equivalent width of the near-IR calcium triplet lines. Our cluster membership analysis was carried out using criteria that include radial velocities, metallicities, proper motions, and distances from the cluster center.
Results. The mean cluster radial velocity and metallicity were determined with a typical error of 2.1 km s−1 and 0.03 dex, respectively. We added this information to that available in the literature for other clusters studied with the same method, compiling a final sample of 48 clusters with metallicities that were homogeneously determined. The clusters of the final sample are distributed across an area of ∼70 deg2 and cover an age range from 0.4 Gyr to 10.5 Gyr. This is the largest sample of spectroscopically analyzed SMC clusters available to date.
Conclusions. We confirm the large cluster metallicity dispersion (∼0.6 dex) at any given age in the inner region of the SMC. The metallicity distribution of our new cluster sample shows a lower probability of being bimodal than suggested in previous studies. The separate chemical analysis of clusters in the six components (Main Body, Counter-Bridge, West Halo, Wing/Bridge, Northern Bridge, and Southern Bridge) shows that only clusters belonging to the Northern Bridge appear to trace a V-Shape, showing a clear inversion of the metallicity gradient in the outer regions. There is a suggestion of a metallicity gradient in the West Halo, similar to that previously found for field stars. It presents, however, a very broad uncertainty. Also, clusters belonging to the West Halo, Wing/Bridge, and Southern Bridge exhibit a well-defined age-metallicity relation with relatively little scatter in terms of abundance at a fixed age compared to other regions.
Moving structures in ultraviolet bright points: Observations from Solar Orbiter/EUI
Authors: Li Dong 
Published: April 2022

Context. Moving structures have been detected in coronal bright points and in a solar flare in active regions that are bidirectional, symmetrical, simultaneous, and quasi-periodic. These could be regarded as observational evidence of plasma outflows via magnetic reconnection.
Aims. We explored pairs of moving structures in fifteen ultraviolet bright points (UBPs), which were observed in the quiet Sun or inside a small active region on 19 November 2020.
Methods. The UBPs were measured by the High Resolution (HRI) Telescopes of the Extreme Ultraviolet Imager (EUI) on board the Solar Orbiter (SolO) in two passbands, HRIEUV 174 Å and HRILyα 1216 Å. The pairs of moving structures are identified in time-distance slices along curved slits of UBPs and their quasi-periods are determined from the fast Fourier transform and wavelet analysis methods.
Results. Moving structures observed in ten UBPs, starting from their bright cores and propagating toward two ends, are interpreted as diverging motions of bidirectional moving structures. These moving structures are also characterized by simultaneity and symmetry and in the case of seven UBPs, they exhibit quasi-periodicity. Moving structures seen in another five UBPs, originating from double ends, moving closer, and merging together are manifested as converging motions. A sympathetic UBP induced by the primary UBP is observed at the edge of a small active region and their moving structures also show the converging motion.
Conclusions. The diverging motions of bidirectional moving structures could be generated by outflows after magnetic reconnections. The converging motions of two moving structures might be caused by inflows through the magnetic reconnection or could also be interpreted as upflows driven by the chromospheric evaporation.
Efficacy and Safety of Hypomethylating Agents in Chronic Myelomonocytic Leukemia: A Single-Arm Meta-analysis
Authors: Zheng Xinhui , Lv Liwei , Li Xiangjun , Jiang Erlie 
Published: April 2022

AbstractBackground Chronic myelomonocytic leukemia (CMML) is a myeloid neoplasm with features of the myelodysplastic syndromes (MDSs) and myeloproliferative neoplasm presenting with peripheral blood monocytosis and an inherent risk for transformation to acute myeloid leukemia, while the abnormal DNA methylation plays a critical role in the pathogenesis of MDS, which is a disease of disordered differentiation. Recently, with the rapid development of molecular biology, hypomethylating agents (HMAs) for the treatment of MDS has gradually become a research focus. The objective of this study was to evaluate the benefits and risks of HMAs for patients with CMML.Materials and Methods PubMed, Embase, the Cochrane Library, and three Chinese databases were searched for studies published before November 2020 that used HMAs in CMML.Results The pooled objective response rate (ORR), complete response (CR), and partial response (PR) were 50.0, 21.0, and 2.0%, respectively. The proportion of patients with minor response (MR) was significantly higher for decitabine (DAC) than for azacitidine (AZA). There was no significant difference in hematologic improvement, ORR, CR, and PR rates between the DAC and AZA groups. Hematological toxicity included neutropenia grade 3/4 (14.0%), anemia grade 3/4 (17.0%), and thrombocytopenia grade 3/4 (22.0%).Conclusion This study showed that HMAs were effective and safe in the treatment of CMML, but large multicenter study would be needed to confirm the efficacy of HMAs for the treatment of CMML with different risk level and genetic abnormality, to support individualization treatment theoretically.
Severe Traumatic Brain Injury in French-Speaking Pediatric Intensive Care Units: Study of Practices
Authors: Denis Manon , Lauzier Benjamin , Roumeliotis Nadia , Orliaguet Gilles , Emeriaud Guillaumes , Javouhey Etienne , Brossier David 
Published: April 2022

AbstractBest strategies for managing severe pediatric traumatic brain injury (TBI) are not established, with wide variations among professional practices. The main objective of this study was to assess compliance with updated pediatric TBI management guidelines (2019). A survey was distributed among French-speaking pediatric intensive care physicians from April 1 to June 30, 2019. The survey was based on a clinical case with a total of 70 questions that cover the 15 items of the 2019 TBI guidelines. The questions evaluated the assessment and management of TBI during the acute and intensive care phases. Of 487 e-mails sent, 78 surveys were included. Guidelines were adhered to (> 60%) for 10 of 15 items in the guidelines. Strong adherence to recent guideline changes was achieved for seizure prophylaxis with levetiracetam (n = 21/33, 64%) and partial pressure of carbon dioxide threshold (n = 52, 67%). However, management of the sodium and glucose thresholds and the role of transcranial Doppler were not consistent with the guidelines. Assessment of brain tissue oxygenation (n = 12, 16%) and autoregulation (n = 35, 45%) was not a common practice. There was strong agreement among clinicians on the intracranial pressure (> 80%) and cerebral perfusion pressure (> 70%) thresholds used according to age. Overall, stated practices for the management of TBI appear to be relatively standardized among responders. Variations persist in areas with a lack of evidence and pediatric-specific recommendations.
Catastrophic Progressive Hearing Loss in Childhood
Authors: Hayes Deborah , Dreith Susan 
Published: April 2022

AbstractWe present a report on a 5-year-old child with a complex medical and audiologic history who exhibited catastrophic progression in hearing loss. Hearing loss was initially attributed to bacterial meningitis at age 3 months; progression was apparently related to perilymph fistula at age 8 years. Etiologies associated with progressive hearing loss in children as well as signs of progression and monitoring protocols for children at risk for progressive hearing loss are discussed.
Abbreviations: ABR = auditory brainstem response, CMV = cytomegalovirus, JCIH = Joint Committee on Infant Hearing, LVA = large vestibular aqueduct, PPHN = persistent pulmonary hypertension of the newborn, TCH = The Children's Hospital
Advanced age increases frequencies of de novo mitochondrial mutations in macaque oocytes and somatic tissues
Authors: Arbeithuber Barbara , Cremona Marzia A. , Hester James , Barrett Alison , Higgins Bonnie , Anthony Kate , Chiaromonte Francesca , Diaz Francisco J. , Makova Kateryna D. 
Published: April 2022

Significance
Multiple human genetic diseases are caused by mutations in the maternally transmitted DNA of mitochondria, the powerhouses of the cell. It is important to study how these mutations arise and accumulate with age, especially because humans in many societies now choose to have children at an older age. However, this is difficult to accomplish in humans, particularly for female germline cells, oocytes. To overcome this limitation, we studied mitochondrial mutation origins and accumulation with age in a primate model species, rhesus macaque. We found that new mutations accumulate the fastest in metabolically active liver and the slowest in oocytes. Thus, primate oocytes might have developed a mechanism to protect their mitochondrial DNA from excessive mutations, allowing reproduction later in life.
Inhaling salbutamol may decrease time to exhaustion in some contexts of heavy endurance performances
Authors: Helge T. , Godhe M. , Berglund B. , Ekblom B. 
Published: April 2022

ABSTRACTPurpose: To study the effect of inhaling a beta‐agonist (salbutamol) compared to placebo on skiing and cycling performance in well‐trained elite athletes. Methods: Three different exercise protocols were used, all with a cross‐over double blind placebo‐controlled design. Participants inhaled 800 µg salbutamol or a placebo prior to the test, which was repeated on a following day with the participants inhaling the other substance. Fifteen junior elite skiers performed four free‐style high intensity sprints (1100 m/work time 3.5–4.5 min). Twelve elite cyclists carried out a short cycling protocol, starting with two 5 min submaximal workloads followed by a maximal intermittent performance test to exhaustion. Another 12 elite cyclists performed the maximal intermittent performance test to exhaustion after a 150 min long submaximal cycling protocol. Results: Group mean time for the ski sprints increased, with no difference between treatment groups. In the short cycling protocol time to exhaustion was 9.1% (95% CI 52–161) lower after inhaling salbutamol compared to placebo and in the long cycling protocol time to exhaustion was 9.1% (95% CI – 121–267) lower after inhaling salbutamol compared to placebo. Blood lactate, heart rate and ventilation increased during submaximal exercise with salbutamol compared to placebo in the short cycling protocol (p < .05). Conclusion: This study could not confirm any positive performance effects from inhaling 800 µg salbutamol compared to placebo in skiing and high‐intensity intermittent cycling performance. Instead, time to exhaustion in the maximal intermittent performance test was lower in both cycling protocols.Highlights
There was no difference in performance time between salbutamol and placebo treatment in real‐life applicable repeated ski sprints.
Time to exhaustion in the maximal intermittent performance test was 9.1% lower after inhaling salbutamol compared to placebo, both when performed after 10 and 150 min of submaximal cycling.
Polarization-resolved analysis to solid high-order harmonic generation
Authors: Huang Tengfei , Li Liang , Li Jiapeng , Zhu Xiaosong , Lan Pengfei , Lu Peixiang 
Published: April 2022

Abstract
We propose a quantitative polarization-resolved quantum trajectory approach to analyse the solid high-order harmonic generation (HHG). By using this approach, we can distinguish the ionization channels of different polarization components in HHG. We take the HHG in hBN under two counter-rotating circularly polarized fields as an example. We find that the right and left circular polarized high harmonics are contributed by the electron trajectories with the ionization channel around the high symmetry points K and K′ respectively. Furthermore, the intensity of the right and left circular polarization harmonics is determined by the interference between these electron trajectories. Our work offers a quantitatively polarization-resolved analysis to understand the underlying mechanism in HHG in the view of electron reciprocal space trajectory.
Construction of highly efficient carbon dots-based polymer photonic luminescent solar concentrators with sandwich structure
Authors: Xin Wei , Wang Jianying , Xu Bing , Wu Jun , Wang Jun , Ren Zhanpeng , Cai Chen , Xue Chenglong , Li Jinhua , Wang Xianbao 
Published: April 2022

Abstract
The enhancement of photoluminescence (PL) emission and waveguide play a key role in improving the optical efficiency of luminescent solar concentrators (LSCs). In this work, to boosting PL emission and waveguide simultaneously, one photonic crystal (PC) structure (crystalline colloid arrays (CCAs)) was introduced into carbon dots (CDs)-based polymer LSCs. A sandwich-structured CDs-based polymer photonic LSC, comprising glass/CDs-based polymer PC film/glass, was created. First, CDs-based colloidal crystal suspensions were prepared by co-assembly of monodispersed p(MMA-NIPAm) colloids and multicolor-emitting CDs in HEMA monomer induced by the evaporation-driven assembly. The obtained suspensions not only had uniform PL and structural colors, but showed enhanced PL emission. Second, the above suspensions were sandwiched between two glass sheets and finally a photonic polymer LSC with sandwiched structure (25 × 25 × 1.8 mm3) were formed via one-step photopolymerization technique. Remarkably, the optimal CDs-based polymer photonic LSCs with sandwiched structure not only had high transparence at visible range (>60%), but exhibited PL emission enhancement (at least 2 times). Furthermore, the maximum external optical efficiency (η

opt
) of 5.84% could be achieved based on yellow-emitting CDs-based polymer photonic LSC. The high external optical efficiency was mainly attributed to the PL emission enhancement and good PC waveguide.
Experimental investigation of the factors that affect the magnitude of the centripetal force exerted on a rotating body in a flipped classroom
Authors: Pierratos Theodoros , Sotirios Mandiliotis , Eirini Dermitzaki 
Published: April 2022

Abstract
Teaching of centripetal force in secondary education is a challenging task because of its central role in the circular and rotational motion. The specific equipment needed for experiments that explore the physical law which governs the centripetal force is usually limited in schools. The experiment presented in this paper, is based on a device which was made from scratch. It has been used in a flipped classroom to engage students in an inquiry-based experimental process. In the synchronous and asynchronous distance learning sessions students worked on the experimental data of circular motion and the uncertainties of them. They made predictions for the dependence of centripetal force on mass, angular velocity and radius of rotation and they got familiar with the scientific methodology. According to their responses to a short questionnaire posed, most of them had a positive attitude towards the teaching module applied.
Optimization of a customized simultaneous algebraic reconstruction technique algorithm for phase-contrast breast computed tomography
Authors: Donato S , Brombal L , Arana Peña L M , Arfelli F , Contillo A , Delogu P , Di Lillo F , Di Trapani V , Fanti V , Longo R , Oliva P , Rigon L , Stori L , Tromba G , Golosio B 
Published: April 2022

Abstract

Objective. To introduce the optimization of a customized GPU-based simultaneous algebraic reconstruction technique (cSART) in the field of phase-contrast breast computed tomography (bCT). The presented algorithm features a 3D bilateral regularization filter that can be tuned to yield optimal performance for clinical image visualization and tissues segmentation. Approach. Acquisitions of a dedicated test object and a breast specimen were performed at Elettra, the Italian synchrotron radiation (SR) facility (Trieste, Italy) using a large area CdTe single-photon counting detector. Tomographic images were obtained at 5 mGy of mean glandular dose, with a 32 keV monochromatic x-ray beam in the free-space propagation mode. Three independent algorithms parameters were optimized by using contrast-to-noise ratio (CNR), spatial resolution, and noise texture metrics. The results obtained with the cSART algorithm were compared with conventional SART and filtered back projection (FBP) reconstructions. Image segmentation was performed both with gray scale-based and supervised machine-learning approaches. Main results. Compared to conventional FBP reconstructions, results indicate that the proposed algorithm can yield images with a higher CNR (by 35% or more), retaining a high spatial resolution while preserving their textural properties. Alternatively, at the cost of an increased image ‘patchiness’, the cSART can be tuned to achieve a high-quality tissue segmentation, suggesting the possibility of performing an accurate glandularity estimation potentially of use in the realization of realistic 3D breast models starting from low radiation dose images. Significance. The study indicates that dedicated iterative reconstruction techniques could provide significant advantages in phase-contrast bCT imaging. The proposed algorithm offers great flexibility in terms of image reconstruction optimization, either toward diagnostic evaluation or image segmentation.
Extraction of the edge/areal components and path of the reverse gate leakage in a GaN HEMT from measurements
Authors: Prasannanjaneyulu Bhavana , Rawal D S , Karmalkar Shreepad 
Published: April 2022

Abstract
Reverse gate leakage, I
G, limits the reliability of gallium nitride high electron mobility transistors. We extract the components of I
G flowing into the edge and area of the gate from the measured I
G versus gate to source voltage, V
GS, data of both low and high I
G devices. The components are separated by analyzing the change in I
G with gate length, L
G. We estimate the short and long channel limits of L
G for which the I
G flows predominantly into the edge and area, respectively. Prior one-dimensional I
G models based on the areal field are valid for simulating long channel devices. However, the I
G of short channel devices should be modeled using the edge field, and can be reduced by techniques like field plate or high-k passivation which reduce the edge field. Also, we find the measured I
G to be independent of the un-gated length, implying that I
G flows via the channel rather than surface. Our work dispels any prior misperception of I
G being area dominated irrespective of L
G and gives the right direction for modeling and control of I
G.
Seismic performance assessment of steel frames upgraded with shape memory alloy re-centering dampers for passive protection of structures subjected to seismic excitations using high-performance NiTiHfPd material
Authors: S Dizaji Farzad , S Dizaji Mehrdad 
Published: April 2022

Abstract
This study explores a super-elastic memory alloy re-centering damper device and investigates its performance in improving the response of steel frame structures subjected to multi-level seismic hazard. The configuration of the device was initially proposed by the authors in a different paper. The proposed super-elastic memory alloy re-centering damper (SMARD) counts on high-performance shape memory alloy (SMA) bars for re-centering capability and employs friction springs to augment its deformation capacity. First of all, this study explores the super-elastic response of NiTiHfPd SMAs under various conditions and illustrates their application into seismic applications. In order to collect experimental data, uniaxial tests are conducted on super-elastic NiTiHfPd SMAs in the temperature range of −35 °C–25 °C and at the loading frequencies of 0.05 Hz to 1.0 Hz with four different strain amplitudes. The effects of loading rate and temperature on super-elastic characteristics of NiTiHfPd SMAs are examined. Then, an analytical model of six-story and nine-story steel special moment frame buildings with installed SMARDs is developed to determine the dynamic response of the building. Finally, nonlinear response time history analyses are conducted to assess the behavior of controlled and uncontrolled buildings under 44 ground motion records. Results show that SMARDs can enormously mitigate the dynamic response of steel frame structures at different seismic hazard levels and, at the same time, enhance their post-earthquake functionality.