bluuebunny/crossref_metadata_2025_split huggingface dataset:
Satellites’ orbital stability through normal forms
Authors: De Blasi Irene , Celletti Alessandra , Efthymiopoulos Christos 
Published: May 2022

AbstractA powerful tool to investigate the stability of the orbits of natural and artificial bodies is represented by perturbation theory, which allows one to provide normal form estimates for nearly-integrable problems in Celestial Mechanics. In particular, we consider the orbital stability of point-mass satellites moving around the Earth. On the basis of the J2 model, we investigate the stability of the semimajor axis. Using a secular Hamiltonian model including also lunisolar perturbations, the so-called geolunisolar model, we study the stability of the other orbital elements, namely the eccentricity and the inclination. We finally discuss the applicability of Nekhoroshev’s theorem on the exponential stability of the action variables. To this end, we investigate the non-degeneracy properties of the J2 and geolunisolar models. We obtain that the J2 model satisfies a “three-jet” non-degeneracy condition, while the geolunisolar model is quasi-convex non-degenerate.
New results on orbital resonances
Authors: Malhotra Renu 
Published: May 2022

AbstractPerturbative analyses of planetary resonances commonly predict singularities and/or divergences of resonance widths at very low and very high eccentricities. We have recently re-examined the nature of these divergences using non-perturbative numerical analyses, making use of Poincaré sections but from a different perspective relative to previous implementations of this method. This perspective reveals fine structure of resonances which otherwise remains hidden in conventional approaches, including analytical, semi-analytical and numerical-averaging approaches based on the critical resonant angle. At low eccentricity, first order resonances do not have diverging widths but have two asymmetric branches leading away from the nominal resonance location. A sequence of structures called “low-eccentricity resonant bridges” connecting neighboring resonances is revealed. At planet-grazing eccentricity, the true resonance width is non-divergent. At higher eccentricities, the new results reveal hitherto unknown resonant structures and show that these parameter regions have a loss of some – though not necessarily entire – resonance libration zones to chaos. The chaos at high eccentricities was previously attributed to the overlap of neighboring resonances. The new results reveal the additional role of bifurcations and co-existence of phase-shifted resonance zones at higher eccentricities. By employing a geometric point of view, we relate the high eccentricity phase space structures and their transitions to the shapes of resonant orbits in the rotating frame. We outline some directions for future research to advance understanding of the dynamics of mean motion resonances.
The Lidov-Kozai resonance at different scales
Authors: Libert Anne-Sophie 
Published: May 2022

AbstractThe Lidov-Kozai (LK) resonance is one of the most widely discussed topics since the discovery of exoplanets in eccentric orbits. It constitutes a secular protection mechanism for systems with high mutual inclinations, although large variations in eccentricity and inclination are observed. This review aims to illustrate how the LK resonance influences the dynamics of the three-body problem at different scales, namely i) for two-planet extrasolar systems where the orbital variations occur in a coherent way such that the system remains stable, ii) for inclined planets in protoplanetary discs where the LK cycles are produced by the gravitational force exerted by the disc on the planet, iii) for migrating planets in binary star systems, whose dynamical evolution is strongly affected by the LK resonance even without experiencing a resonance capture, and iv) for triple-star systems for which the migration through LK cycles combined with tidal friction is a possible explanation for the short-period pile-up observed in the distribution of multiple stars.
Noise, friction and the radial-orbit instability in anisotropic stellar systems: stochastic N–body simulations
Authors: Di Cintio Pierfrancesco , Casetti Lapo 
Published: May 2022

AbstractBy means of numerical simulations we study the radial-orbit instability in anisotropic self-gravitating N–body systems under the effect of noise. We find that the presence of additive or multiplicative noise has a different effect on the onset of the instability, depending on the initial value of the orbital anisotropy.
Weak stability transition region near the orbit of the Moon
Authors: Makó Zoltán , Salamon Júlia 
Published: May 2022

AbstractThis paper provides a study on the weak stability transition region in the framework of the planar elliptic restricted three-body problem. We define the lower boundary curve of the weak stability transition region and as a particular case, we determine this curve in the Sun-Earth system. The orbit of the Moon is near the lower boundary of the weak stability transition region.
On Tides and Exoplanets
Authors: Ferraz-Mello S. 
Published: May 2022

AbstractThis paper reviews the basic equations used in the study of the tidal variations of the rotational and orbital elements of a system formed by one star and one close-in planet as given by the creep tide theory and Darwin’s constant time lag (CTL) theory. At the end, it reviews and discusses the determinations of the relaxation factors (and time lags) in the case of host stars and hot Jupiters based on actual observations of orbital decay, stellar rotation and age, etc. It also includes a recollection of the basic facts concerning the variations of the rotation of host stars due to the leakage of angular momentum associated with stellar winds.
Evolution and stability of Laplace-like resonances under tidal dissipation
Authors: Celletti A. , Karampotsiou E. , Lhotka C. , Pucacco G. , Volpi M. 
Published: May 2022

AbstractThe Laplace resonance is a configuration that involves the commensurability between the mean motions of three small bodies revolving around a massive central one. This resonance was first observed in the case of the three inner Galilean satellites, Io, Europa, and Ganymede. In this work the Laplace resonance is generalised by considering a system of three satellites orbiting a planet that are involved in mean motion resonances. These Laplace-like resonances are classified in three categories: first-order (2:1&2:1, 3:2&3:2, 2:1&3:2), second-order (3:1&3:1) and mixed-order resonances (2:1&3:1). In order to study the dynamics of the system we implement a model that includes the gravitational interaction with the central body, the mutual gravitational interactions of the satellites, the effects due to the oblateness of the central body and the secular interaction of a fourth satellite and a distant star. Along with these contributions we include the tidal interaction between the central body and the innermost satellite. We study the survival of the Laplace-like resonances and the evolution of the orbital elements of the satellites under the tidal effects. Moreover, we study the possibility of capture into resonance of the fourth satellite.
Cascade disruption in Rampo family
Authors: Vasileva Mariia , Kuznetsov Eduard , Rosaev Alexey , Plávalová Eva 
Published: May 2022

AbstractWe have found three new members of the Rampo asteroids family: 2009HD95, 2010VO19, 2013JF69. We estimated the Yarkovsky semimajor axis drift rate. Based on the simulation results, estimates of the asteroid pairs’ age included in the family are obtained. In the scenario of the cascade disruption of the parent body of the asteroid (10321) Rampo, one can note the concentration of estimates of the pairs’ age to values of 900, 750, 500, and 250 kyr.
Neonatal Outcome in Twin-to-Twin Transfusion Syndrome Not Treated with Fetoscopic Laser Surgery
Authors: Lopriore Elina A. , Slaghekke Femke , Verweij E. Joanne , Haak Monique C. , Middeldorp Annemieke J. M. , Lopriore Enrico 
Published: May 2022

AbstractThe aim of this study was to describe the neonatal management and outcome in monochorionic twins with twin-to-twin transfusion syndrome (TTTS) not treated with fetoscopic laser surgery. All consecutive live-born neonates with TTTS managed at our center between 2002 and 2021 were included in this retrospective study. Neonatal outcome was assessed in 44 twin pairs with TTTS not treated with laser (nonlaser group) compared to a control group of 88 twin pairs with TTTS successfully treated with laser (laser group), matched for gestational age at birth. Primary outcome was adverse neonatal outcome, a composite outcome including neonatal mortality or severe neonatal morbidity. The incidence of adverse neonatal outcome in the nonlaser group and laser group was 30% (26/88) and 11% (19/176), respectively (relative risk = 3.46, 95% CI [1.79, 6.71]). In the nonlaser group, 11% had necrotizing enterocolitis (vs. 2% in the laser group) and 24% had hypotension (vs. 10% in the laser group). Recipients in the nonlaser group had, compared to recipients in the laser group, significantly more severe cerebral injury (18% vs. 5%) and more polycythemia at birth (21% vs. 1%). Donors in the nonlaser group had, compared to donors in the laser group, more severe growth restriction (71% vs 42%), renal failure (11% vs 1%), and anemia at birth (25% vs. 7%). Thus, the risk for neonatal mortality and/or severe morbidity is three-fold higher in TTTS not treated with laser than in TTTS treated with laser, which highlights the fact that these neonates with TTTS are very sick at birth, requiring accurate and prompt intensive treatment.
Seismic Detection of Euroquakes Originating From Europa's Silicate Interior
Authors: Marusiak A. G. , Panning M. P. , Vance S. D. , Nunn C. , Stähler S. C. , Tharimena S. 
Published: May 2022

AbstractDetecting a seismic event from Europa's silicate interior would provide information about the geologic and tectonic setting of the moon's rocky interior. However, the subsurface ocean will attenuate the signal, possibly preventing the waveforms from being detected by a surface seismometer. Here, we investigate the minimum magnitude of a detectable event originating from Europa's silicate interior. We analyze likely signal‐to‐noise ratios and compare the predicted signal strengths to current instrument sensitivities. We show that a magnitude Mw ≥ 3.5 would be sufficient to overcome the predicted background noise when the ice shell is 5 km thick. However, a minimum magnitude of Mw ≥ 5.5 would be required for current instrumentation to be able detect the event for any ice shell thickness, at any distance. A thinner ice shell transmits greater ground acceleration amplitudes than a thicker ice shell, which might allow for Mw ≥ 4.5 to be detectable.
An Automated Method for Mapping Independent Spatial b Values
Authors: Godano C. , Convertito V. , Pino N. A. , Tramelli A. 
Published: May 2022

AbstractWe present an automated method for mapping the b values. The algorithm is very simple and presents three advantages: (a) it does not requires any tuning of the parameters like, for instance, a fixed cell size or a maximum radius of the cell; (b) it implies a more appropriate use of the catalog, by using almost all the events in the catalog used (with a tolerance of 1%) with no overlap; (c) it implies the full independence of the b values, thus allowing the statistical comparison of the results using standard tests. Although the resulting b values are comparable with those obtained by applying the other methods of common use in seismology, these latter (a) leave out many earthquakes from the analysis, with loose of useful information, (b) produce diffuse cells overlapping aiming at reaching many cells of the grid in order to get the correct number of events in each cell, and (c) results in correlated b values, which do not allow the test of significance for the differences in the b values. Finally, due to the independence from any ad hoc a‐priori choice, our method is suitable for automatic and operator‐free procedures.
Characteristics of VOC Composition at Urban and Suburban Sites of New Delhi, India in Winter
Authors: Tripathi Nidhi , Sahu L. K. , Wang Liwei , Vats Pawan , Soni Meghna , Kumar Purushottam , Satish R. V. , Bhattu Deepika , Sahu Ravi , Patel Kashyap , Rai Pragati , Kumar Varun , Rastogi Neeraj , Ojha Narendra , Tiwari Shashi , Ganguly Dilip , Slowik Jay , Prévôt André S. H. , Tripathi Sachchida N. 
Published: May 2022

AbstractSimultaneous measurements of volatile organic compounds (VOCs) using two PTR‐TOF‐MS instruments were conducted at urban and suburban sites of New Delhi during the winter of 2018. The time series of VOC mixing ratios show substantial variations mainly influenced by local emissions and meteorological conditions. Mixing ratios of methanol (∼28 ppbv), acetaldehyde (7.7 ppbv), acetone (10.6 ppbv), isoprene (2.8 ppbv) and monoterpenes (0.84 ppbv) at the suburban site were higher than those at the urban site, while levels of aromatic VOCs were almost similar. The strong nighttime correlations of isoprene and monoterpenes with CO and benzene at the urban site indicate their predominant anthropogenic origin. Higher emission ratios of ∆VOCs/∆CO and ∆VOCs/∆benzene than those reported for vehicular exhaust suggest the contributions of other sources. In addition to vehicular emissions, episodes of biomass burning, industrial plumes and aged air strongly influenced the levels of VOCs at the suburban site. Despite the predominant primary anthropogenic emissions, the higher daytime enhancements of OVOCs/CO ratios indicate additional contributions of OVOCs from secondary/biogenic sources. The secondary formation of OVOCs in moderately aged air masses was noticeable at the suburban site. Using the source‐tracer‐ratio method, the estimated biogenic contributions of isoprene (71%) and acetone (65%) during daytime at the suburban site were significantly higher than those for the urban site. The photochemical box model simulations suggest that daytime ozone formation was under the VOC‐limited regime. The present study highlights the impact of different emission sources, photochemical processes and meteorological conditions on the composition and concentration of VOCs in the Delhi region.
Correlation of Venusian Mesoscale Cloud Morphology Between Images Acquired at Various Wavelengths
Authors: Narita M. , Imamura T. , Lee Y. J. , Watanabe S. , Yamazaki A. , Satoh T. , Taguchi M. , Sato T. M. , Fukuhara T. , Yamada M. , Kouyama T. , Iwagami N. 
Published: May 2022

AbstractThe differences and similarities in morphologies acquired across various wavelengths in simultaneously obtained Venus' dayside images may provide clues on cloud/atmospheric physics and chemistry. Here, we focus on spatial scales smaller than ∼600 km, where cell‐like or streaky features seem to dominate in ultraviolet images. Using images acquired at ultraviolet wavelengths of 283 nm, 365 nm, and infrared wavelengths of 0.90, 2.02, and 10 μm by the Venus orbiter Akatsuki, correlation coefficient maps between pairs of wavelengths, such as 2.02 μm/10 μm, 2.02 μm/283 nm, 2.02 μm/365 nm, 283 nm/365 nm, and 0.90 μm/2.02 μm were created. Our results show a clear negative correlation between images obtained at 2.02 μm (CO2 absorption) and 10 μm (cloud top temperature), meaning that elevated clouds are cooled by adiabatic expansion or the ambient air. A clear negative correlation was found between 2.02 μm and 283 nm (SO2 absorption), suggesting that SO2 is transported to the cloud top region during cloud ascent. We observed a clear positive correlation between images obtained at 283 and 365 nm (unknown absorber), implying a close relationship between the unknown absorber and SO2 or a non‐negligible contribution of the unknown absorber at 283 nm. We found a low correlation between images obtained at 0.90 μm (middle/lower cloud) and 2.02 μm, suggesting a weak vertical coupling in the clouds.
Association between built environments and weight status: evidence from longitudinal data of 9589 Australian children
Authors: Putra I Gusti Ngurah Edi , Astell-Burt Thomas , Feng Xiaoqi 
Published: May 2022

AbstractBackgroundNo studies appear to examine potential associations between changes in built environments across childhood and the developmental trajectories of child weight status.ObjectiveExamine the developmental trajectories of child weight status with respect to changes in childhood exposure to the built environments.MethodsThis study used data of 9589 children with biennial follow-up (2004–2016), retrieved from the Longitudinal Study of Australian Children. Changes in objectively-measured child weight status (i.e., body mass index-BMI, waist circumference) were investigated in relation to changes in seven built environments (i.e., neighbourhood safety; green space quality; footpaths and street conditions; public transport; shopping facilities; basic services; and local traffic) subjectively reported by caregivers. Group-based discrete trajectory mixture models were used to classify children according to their developmental trajectories of built environments and weight status. Multilevel multinomial logistic regression was employed to examine associations between built environments and child weight status adjusted for confounding.ResultsTwo, four, and six trajectory groups were developed for built environment variables. Three groups namely “moderate”, “high”, and “extreme increase” were generated for each BMI and waist circumference. Findings from multilevel analyses indicated that growing up in neighbourhoods that are considered highly safe, with better quality of green space nearby, and in areas with low local traffic over time are protective against unhealthy weight increase in childhood. Meanwhile, living with better access to shopping facilities and basic services was associated with an unhealthy increase in BMI and/or waist circumference. No clear associations appeared between the quality of footpath and street conditions, access to public transport, and child weight status.ConclusionsBuilt environments might act either as a risk or protective factor of an unhealthy increase in child weight status. Enabling health-promoting neighbourhoods (i.e., highly safe, quality green space nearby, low local traffic) is important to support a healthy weight trajectory across childhood.
Intrinsic superflat bands in general twisted bilayer systems
Authors: Wang Hongfei , Ma Shaojie , Zhang Shuang , Lei Dangyuan 
Published: May 2022

AbstractTwisted bilayer systems with discrete magic angles, such as twisted bilayer graphene featuring moiré superlattices, provide a versatile platform for exploring novel physical properties. Here, we discover a class of superflat bands in general twisted bilayer systems beyond the low-energy physics of magic-angle twisted counterparts. By considering continuous lattice dislocation, we obtain intrinsic localized states, which are spectrally isolated at lowest and highest energies and spatially centered around the AA stacked region, governed by the macroscopic effective energy potential well. Such localized states exhibit negligible inter-cell coupling and support the formation of superflat bands in a wide and continuous parameter space, which can be mimicked using a twisted bilayer nanophotonic system. Our finding suggests that general twisted bilayer systems can realize continuously tunable superflat bands and the corresponding localized states for various photonic, phononic, and mechanical waves.
Advanced liquid crystal devices for augmented reality and virtual reality displays: principles and applications
Authors: Yin Kun , Hsiang En-Lin , Zou Junyu , Li Yannanqi , Yang Zhiyong , Yang Qian , Lai Po-Cheng , Lin Chih-Lung , Wu Shin-Tson 
Published: May 2022

AbstractLiquid crystal displays (LCDs) and photonic devices play a pivotal role to augmented reality (AR) and virtual reality (VR). The recently emerging high-dynamic-range (HDR) mini-LED backlit LCDs significantly boost the image quality and brightness and reduce the power consumption for VR displays. Such a light engine is particularly attractive for compensating the optical loss of pancake structure to achieve compact and lightweight VR headsets. On the other hand, high-resolution-density, and high-brightness liquid-crystal-on-silicon (LCoS) is a promising image source for the see-through AR displays, especially under high ambient lighting conditions. Meanwhile, the high-speed LCoS spatial light modulators open a new door for holographic displays and focal surface displays. Finally, the ultrathin planar diffractive LC optical elements, such as geometric phase LC grating and lens, have found useful applications in AR and VR for enhancing resolution, widening field-of-view, suppressing chromatic aberrations, creating multiplanes to overcome the vergence-accommodation conflict, and dynamic pupil steering to achieve gaze-matched Maxwellian displays, just to name a few. The operation principles, potential applications, and future challenges of these advanced LC devices will be discussed.
Graphene-driving novel strain relaxation towards AlN film and DUV photoelectronic devices
Authors: Nguyen Hieu. P. T. 
Published: May 2022

AbstractGraphene-driving strain-pre-store engineering enables the epitaxy of strain-free AlN film with low dislocation density for DUV-LED and the unique mechanism of strain-relaxation in QvdW epitaxy was demystified.
Structural variants shape the genomic landscape and clinical outcome of multiple myeloma
Authors: Ashby Cody , Boyle Eileen M. , Bauer Michael A. , Mikulasova Aneta , Wardell Christopher P. , Williams Louis , Siegel Ariel , Blaney Patrick , Braunstein Marc , Kaminetsky David , Keats Jonathan , Maura Francesco , Landgren Ola , Walker Brian A. , Davies Faith E. , Morgan Gareth J. 
Published: May 2022

AbstractDeciphering genomic architecture is key to identifying novel disease drivers and understanding the mechanisms underlying myeloma initiation and progression. In this work, using the CoMMpass dataset, we show that structural variants (SV) occur in a nonrandom fashion throughout the genome with an increased frequency in the t(4;14), RB1, or TP53 mutated cases and reduced frequency in t(11;14) cases. By mapping sites of chromosomal rearrangements to topologically associated domains and identifying significantly upregulated genes by RNAseq we identify both predicted and novel putative driver genes. These data highlight the heterogeneity of transcriptional dysregulation occurring as a consequence of both the canonical and novel structural variants. Further, it shows that the complex rearrangements chromoplexy, chromothripsis and templated insertions are common in MM with each variant having its own distinct frequency and impact on clinical outcome. Chromothripsis is associated with a significant independent negative impact on clinical outcome in newly diagnosed cases consistent with its use alongside other clinical and genetic risk factors to identify prognosis.