Average Distance Research Articles

Out-of-plane cross-angle bending stiffness of cross-laminated timber

The increasing use of cross-laminated timber (CLT) in construction worldwide can be attributed to its combination of sustainability, structural efficiency, biaxial strength and stiffness, short construction times, and architectural flexibility. However, when applied in free-form structures, CLT panels may exhibit irregular element geometries, resulting in deviations from their major or minor strength axes. The required out-of-plane cross-angle bending stiffness is not addressed by commonly used design methods. This study addresses this gap by examining the cross-angle bending stiffness of CLT panel segments using experimental, analytical, and numerical methods. Three different lay-ups (3-ply, 4-ply, and 5-ply) and five cross-angles (ranging from 0° to 90°) were tested under 3-point bending, demonstrating the nonlinear relation between cross-angle and out-of-plane bending stiffness. The lowest stiffness was observed for intermediate cross-angles and not when loaded along the minor strength direction. A proposed analytical model that combines the shear analogy with Hankinson's equation yielded adequate approximations. The model was verified by numerical simulations and then applied to predict the out-of-plane cross-angle bending stiffness of a wide range of CLT layups. This research provides valuable insights for working with CLT in complex geometrical designs, enhancing preliminary design.

Temporal variability in transmission spectra of H2-dominated exoplanets: The influence of thermal evolution and stellar irradiation on atmospheric composition

Planets and their host stars undergo evolutionary changes over time, resulting in variations in internal temperature and incoming radiation, which significantly impact the temperature structure and composition of their atmospheres. These evolving conditions give rise to distinctive features in planetary spectra that are observable only during specific stages of planetary evolution. We aim to understand how the composition of planets with H2-dominated atmospheres changes over longer timescales due to their thermal evolution. We also investigate time-dependent features in the transmission spectra. These features could provide insights in both the formation and evolution of these gaseous planets, as well as the timescales of these changes, enabling us to study the potential variability of exoplanets over time. We evolve a ∼0.04 MJup and ∼0.45 MJup planet around a 1.0 M⊙ and 1.3 M⊙ star respectively for 109.5 years. In both systems, the planets are considered at semi-major axes of 0.1 AU and 1.0 AU. The star-planet systems are evolved by making use of Modules for Experiments in Stellar Astrophysics (MESA). The temperature–pressure profiles are obtained at selected time-steps using an analytical approximation based on the internal and irradiation temperature of the planet at each time step. We then use VULCAN, a photochemical kinetics code, to see how the composition changes with time in the atmosphere due to the thermal evolution of the planets. By making use of the radiative transfer code petitRADTrans, we also simulate the evolution of the transmission spectra of the planets to find potential time-dependent spectral features. Our findings show a prominent change in the CO2 feature at ∼4.3μm. For the 0.45 MJup case, this feature is visible in the pre-main-sequence phase of the host star, regardless of orbital distance from the host star. In the case of the ∼0.04 MJup planet, this CO2 feature is visible until t ≤ 106 years, and then it reappears after t ≥ 108 years when the planet is 0.1 AU away the host star. The CH4 features at ∼3.3μm and ∼7.5μm are only time-dependent when the planet is located at 0.1 AU from the host star and experiences high irradiation since the high temperature at early stages favoured CO2 over CH4. When the planet is 1.0 AU away from its host star, the CH4 features are always visible regardless of the mass and hence internal temperature of the planet.

Inter-individual variability in elliptical and diagonal error distributions potentially relevant to optimal motor planning in football instep kicking

The distribution of motor errors can influence optimal motor planning (where to aim). In football instep kicking, it was shown that ball landing locations exhibit the right-up-left-down elliptical distribution in right-footed kickers and vice versa. However, this was reported as a result of mixed multiple kickers; the individual-level error distribution has been unclear. Here we show substantial inter-individual variability in error shape and error direction in the 30 kicks aimed at a target (1.7 m high, 11.0 m in front) by 27 male football players. All players exhibit right-up-left-down distributions with ellipticity (minor/major radius ratio of the 95% confidence ellipse) ranging from 0.25 to 0.77 and major axis angle ranging from 13 to 67° from the horizontal axis. The mean absolute error and the area of the 95% confidence ellipse are not significantly correlated with major axis angle (ρ ≤ 0.312) and ellipticity (|r| ≤ 0.343). By simulating shots aimed at the top-right and top-left edges of a goal with these observed ranges and normalised ellipse area, we reveal a wide range of probability of shots on goal (top-right: 2.7-fold difference, top-left: 1.5-fold difference) due to inter-individual variability in error shape and direction independent of error size. Further simulation shows that, depending on the shape-direction combination, the aiming points with the same 80% probability of shots on goal change by up to 0.3 m vertically, even for the same minimal error size. We highlight the importance for football players to consider not only accuracy/precision, but also error shape and direction to optimise motor planning.

Why Are (Almost) All the Protostellar Outflows Aligned in Serpens Main?

We present deep 1.4–4.8 μm JWST-NIRCam imaging of the Serpens Main star-forming region and identify 20 candidate protostellar outflows, most with bipolar structure and identified driving sources. The outflow position angles (PAs) are strongly correlated, and they are aligned within ±24° of the major axis of the Serpens filament. These orientations are further aligned with the angular momentum vectors of the two disk shadows in this region. We estimate that the probability of this number of young stars being coaligned if sampled from a uniform PA distribution is 10−4. This in turn suggests that the aligned protostars, which seem to be at similar evolutionary stages based on their outflow dynamics, formed at similar times with a similar spin inherited from a local cloud filament. Further, there is tentative evidence for a systematic change in average PA between the northwestern and southeastern cluster, as well as increased scatter in the PAs of the southeastern protostars. SOFIA-HAWC+ archival dust polarization observations of Serpens Main at 154 and 214 μm are perpendicular to the dominant jet orientation in the northwestern region in particular. We measure and locate shock knots and edges for all of the outflows and provide an identifying catalog. We suggest that Serpens main is a cluster that formed from an isolated filament and due to its youth retains its primordial outflow alignment.

A fresh look into the interaction of exoplanets magnetosphere with stellar winds using MHD simulations

Numerous numerical studies have been carried out in recent years that simulate different aspects of exoplanets’ magnetosphere and stellar winds. These studies have focused primarily on hot Jupiters with sun-like stars. This study addresses the challenges inherent in utilizing existing MHD codes to model hot Jupiter-star systems. Due to the scaling of the system and the assumption of a uniformly flowing stellar wind at the outer boundary of the simulation, MHD codes necessitate a minimum distance of greater than 0.4 au for a Jupiter-like planet orbiting a sun-like star to avoid substantial violations of the code’s assumptions. Additionally, employing the GAMERA (Grid Agnostic MHD for Extended Research Applications) MHD code, we simulate star-planet interactions considering various stellar types (Sun-like and M Dwarf stars) with both Jupiter-like and rocky planets positioned at varying orbital distances. Furthermore, we explore the impact of tidal locking on the total power within the magnetosphere-ionosphere systems.

Spatial sampling bias influences our understanding of early hominin evolution in eastern Africa.

The eastern branch of the Eastern African Rift System (EARS) is the source of a large proportion of the early hominin fossil record, but it covers a tiny fraction (ca. 1%) of the continent. Here we investigate how this mismatch between where fossils are preserved and where hominins probably lived may influence our ability to understand early hominin evolution, using extant mammals as analogues. We show that the eastern branch of the EARS is not an environmentally representative sample of the full species range for nearly all extant rift-dwelling mammals. Likewise, when we investigate published morphometric datasets for extant cercopithecine primates, evidence from the eastern branch alone fails to capture major portions of continental-scale cercopithecine cranial morphospace. We suggest that extant rift-dwelling species should be used as analogues to place confidence intervals on hominin habitat reconstructions. Furthermore, given the north-south orientation of the eastern branch of the EARS, morphoclines that are not aligned along this major north-south axis are likely to be poorly sampled by sites in the eastern branch. There is a pressing need for research on the geography of early hominin morphoclines to estimate how morphologically representative the hominin fossil sample from the eastern branch may be.

Spin waves in ferrimagnets near the angular magnetization compensation temperature: A micromagnetic study

Spin wave propagation along a ferrimagnetic strip with out-of-plane magnetization is studied by means of micromagnetic simulations. The ferrimagnetic material is considered to be formed by two antiferromagnetically coupled sub-lattices. Two critical temperatures can be defined for such systems: that of magnetization compensation and that of angular momentum compensation, both different due to distinct Landé factors for each sub-lattice. Spin waves in the strip are excited by a spin current injected at one of its edges. The obtained dispersion diagrams show exchange-dominated forward volume spin waves. For a given excitation frequency, the Néel vector describes highly eccentric orbits, the eccentricity depending on temperature, whose semi-major axis is oriented differently at distinct locations on the FiM strip.

The allometry of brain size in Euarchontoglires: clade-specific patterns and their impact on encephalization quotients

Abstract The timing and nature of evolutionary shifts in the relative brain size of Primates have been extensively studied. Less is known, however, about the scaling of the brain-to-body size in their closest living relatives, i.e., among other members of Euarchontoglires (Dermoptera, Scandentia, Lagomorpha, Rodentia). Ordinary least squares (OLS), reduced major axis (RMA), and phylogenetic generalized least squares (PGLS) regressions were fitted to the largest euarchontogliran data set of brain and body mass, comprising 715 species. Contrary to previous inferences, lagomorph brain sizes (PGLS slope = 0.465; OLS slope = 0.593) scale relative to body mass similarly to rodents (PGLS = 0.526; OLS = 0.638), and differently than primates (PGLS = 0.607; OLS = 0.794). There is a shift in the pattern of the scaling of the brain in Primates, with Strepsirrhini occupying an intermediate stage similar to Scandentia but different from Rodentia and Lagomorpha, while Haplorhini differ from all other groups in the OLS and RMA analyses. The unique brain–body scaling relationship of Primates among Euarchontoglires illustrates the need for clade-specific metrics for relative brain size (i.e., encephalization quotients; EQs) for more restricted taxonomic entities than Mammalia. We created clade-specific regular and phylogenetically adjusted EQ equations at superordinal, ordinal, and subordinal levels. When using fossils as test cases, our results show that generalized mammalian equations underestimate the encephalization of the stem lagomorph Megalagus turgidus in the context of lagomorphs, overestimate the encephalization of the stem primate Microsyops annectens and the early euprimate Necrolemur antiquus, but provide similar EQ values as our new strepsirrhine-specific EQ when applied to the early euprimate Adapis parisiensis.

Robot-Assisted 2D Fluoroscopic Needle Placement-A Phantom Study.

To evaluate the targeting accuracy of a novel robot-assisted guidance technique relying on one pair of 2D C-arm images. In total, 160 punctures were carried out semi-automatically by using a novel robotic device. The needle's paths were planned based on one pair of 2D fluoroscopic images from different angles. Conically shaped aluminum tips inside a gelatin-filled plexiglass phantom served as targets. The accuracy of the needle placement was assessed by taking control CTs and measuring the Euclidean distance (ED) and normal distance (ND) between the needle and the target point. In addition, the procedural time per needle placement was evaluated. The accomplished mean NDs at the target for the 45°, 60°, 75° and 90° angles were 1.86 mm (SD ± 0.19), 2.68 mm (SD ± 0.18), 2.19 mm (SD ± 0.18) and 1.86 mm (SD ± 0.18), respectively. The corresponding mean EDs were 2.32 mm (SD ± 0.16), 2.68 mm (SD ± 0.18), 2.65 mm (SD ± 0.16) and 2.44 mm (SD ± 0.15). The mean duration of the total procedure, including image acquisition, trajectory planning and placement of four needles sequentially, was 12.7 min. Robotic guidance based on two 2D fluoroscopy images allows for the precise placement of needle-like instruments at the first attempt without the need for using an invasive dynamic reference frame. This novel approach seems to be a valuable tool for the precise targeting of various anatomical structures that can be identified in fluoroscopic images.

Exocomet orbital distribution around beta Pictoris

The $ sim 23$\,Myr young star beta \,Pictoris (beta \,Pic) is a laboratory for planet formation studies because of its observed debris disk, its directly imaged super-Jovian planets beta \,Pic\,b and c, and the evidence of extrasolar comets that regularly transit in front of the star. The most recent evidence of exocometary transits around beta \,Pic came from stellar photometric time series obtained with the TESS space mission. Previous analyses of these transits constrained the orbital distribution of the underlying exocomet population to a range between about 0.03 and 1.3\,AU assuming a fixed transit impact parameter. We examine the distribution of the observed transit durations Delta t$) to infer the orbital surface density distribution (delta ) of the underlying exocomet sample. The effect of the geometric transit probability for circular orbits was properly taken into account, but we assumed that the radius of the transiting comets and their possible clouds of evaporating material are much smaller than the stellar radius. We show that a narrow belt of exocomets around beta \,Pic, in which the transit impact parameters are randomized but the orbital semimajor axes are equal, results in a pile-up of long transit durations. This is in contrast to observations, which reveal a pile-up of short transit durations Delta t 0.1$\,d) and a tail of only a few transits with Delta t > 0.4$\,d. A flat density distribution of exocomets between about 0.03 and 2.5\,AU results in a better match between the resulting Delta t$ distribution and the observations, but the slope of the predicted $ Delta t$ histogram is not sufficiently steep. An even better match to the observations can be produced with a $ beta $ power law. Our modeling reveals a best fit between the observed and predicted $ Delta t$ distribution for $ A more reasonable scenario in which the exocometary trajectories are modeled as hyperbolic orbits can also reproduce the observed $ Delta t$ distribution to some extent. Future studies might reproduce the observed $ Delta t$ distribution with a full exploration of the four-dimensional parameter space of highly eccentric orbits, and they might need to relax our assumption that the transiting objects are smaller than the stellar disk. The number of observed exocometary transits around beta \,Pic is currently too small to validate the previously reported distinction of two distinct exocomet families, but this might be possible with future TESS observations of this star. Our results nevertheless imply that cometary material exists on highly eccentric orbits with a more extended range of semimajor axes than suggested by previous spectroscopic observations.

Hidden Companions to Intermediate-mass Stars. XXI. Discovery of a 0.5 M ⊙, 1.5 au Companion to Sadachbia = Gamma Aquarii* *Based on observations collected at the European Southern Observatory, Chile, Program ID 113.26GM.001.

Sadachbia = Gamma Aquarii is a nearby A0V star that was suspected to be a spectroscopic binary. Here we report on the direct detection of a companion with a K band flux ratio of 1.2% at a projected separation of 38.2 mas based on a VLTI/GRAVITY near-infrared interferometric observation. The implied mass and separation of the companion are 0.46 M ⊙ and 1.5 au based on the Gaia DR3 distance (or 0.55 M ⊙ and 1.9 au if the discrepant Hipparcos distance is used instead). The companion explains the X-ray emission of γ Aqr and the orbital motion with a period of about one year likely explains the discrepant Gaia and Hipparcos parallaxes. Further observations are necessary to measure the binary semimajor axis but it is likely that the system will undergo common envelope evolution. The primary is partially resolved with an angular diameter of 0.52 mas.

Rocky planet formation in compact disks around M dwarfs

Due to the improvements in radial velocity and transit techniques, we know that rocky or rocky-icy planets, in particular close-in super-Earths in compact configurations, are the most common ones around M dwarfs. On the other hand, thanks to the high angular resolution of ALMA we know that many disks around very low-mass stars (between 0.1 and 0.5 M$_ are rather compact and small (without observable substructures and radius less than 20 au), which favors the idea of an efficient radial drift that could enhance planet formation in the terrestrial zone. Our aim was to investigate the potential formation paths of the observed close-in rocky exoplanet population around M dwarfs, especially close-in super-Earths, assuming that planet formation could take place in compact disks with an efficient dust radial drift. We developed N-body simulations that include a sample of embryos growing by pebble accretion exposed to planet-disk interactions, star-planet tidal interactions, and general relativistic corrections that include the evolution of the luminosity, radius, and rotational period of the star. For a star of 0.1 M$_ we considered different gas disk viscosities and initial embryo distributions. We also explored planet formation by pebble accretion around stars of 0.3 M$_ and 0.5 M$_ Lastly, for each stellar mass, we ran simulations that include a sample of embryos growing by planetesimal accretion instead of pebble accretion. Our main result is that the sample of simulated planets that grow by pebble accretion in a gas disk with low viscosity ($ $) can reproduce the close-in low-mass exoplanet population around M dwarfs in terms of multiplicity, mass, and semi-major axis. Furthermore, we found that a gas disk with high viscosity ($ $), and thus lower pebble accretion rates, cannot reproduce the observed planet masses as no planet more massive than 0.5 M$_ could be formed in our simulations. In addition, we show that planetesimal accretion favors the formation of smaller planets than pebble accretion does. Whether this planet population truly exists remains unknown with the current instrumental sensitivity. Rocky planet formation around M dwarfs can take place in compact and small dust disks driven by an efficient radial drift in a gas disk with low viscosity ($ $). This result points toward a new approach in the direction of the disk conditions needed for rocky planet formation around very low-mass stars.

Young dove trees tend to invest more biomass in vegetative and reproductive organs than old trees at the twig level

Research on the functional traits of twigs is of great significance to clarify the plant life-history strategies, especially for endangered plants. However, little attention has been given to the environmental adaptation strategy of different age twigs. The dove tree (Davidia involucrata Baill.), a relict and critically endangered Chinese species, was employed as a model species. Total lamina mass and area, stem mass and length, total bract mass and area, and total petiole mass were measured for 100 current-year terminal twigs (50 per age group) from old and young dove trees in Pingwu County, Sichuan, southwest China. Then, the scaling relationships within the twig were determined using the standardized major axis (SMA) regression method. Our results showed that the significantly positive correlations among traits of D. involucrata twigs, and scaling relationships between these traits are different between the two age groups. At the twig level, isometric scaling relationships exist between stem mass and lamina size (or bract size) and between total lamina mass and total lamina area (or total petiole mass). In contrast, allometric scaling relationships exist between lamina size (total mass and area) and stem length (with a common slope > 1), and between total lamina mass and total petiole mass (with a common slope < 1). For a given stem mass, stem length and bract area, young trees have larger total lamina mass and total bract mass, larger total lamina mass and area, and larger total bract mass than old trees, respectively. The results suggest that young trees tend to have more vegetative and reproductive organ mass per unit of supporting organ mass than old trees to meet their rapid growth needs.

Short fatigue crack growth and retained austenite in steels processed via quenching and partitioning

Previous research has consistently found that introducing metastable retained austenite (RA) as a second phase retards the failure of steel under fatigue. However, the reasons for this benefit are not understood. Accordingly, the properties of RA most advantageous to resist fatigue are not known. Within this context, this paper examines the interaction between second-phase RA and short fatigue crack growth in a steel processed via quenching and partitioning, using quasi in situ electron backscatter diffraction experiments. Results show that most RA transforms into martensite under the plastic strain surrounding the crack. They also reveal various mechanisms whereby RA transformation delays short fatigue crack propagation; transformation-induced crack closure (TICC), crack deflection and branching, and roughness-induced crack closure (RICC). Crack deflection and branching are driven by a tendency of cracks to propagate towards transformed RA, which is against the previous assumptions in the literature. Furthermore, the impact of crack deflection/branching on retardation is more powerful than that of TICC acting alone. Microstructures including second-phase RA should avoid RA-lean areas and promote elongated RA grains, with relatively large size, and major axis normal to the preferential crack growth direction. Untransformed RA within the plastic zone (i.e. overstabilized) does not contribute to crack retardation.

Abstract Tu051: ROR2 Drives Right Ventricular Failure Via Proteostatic Imbalances

Background: No therapies exist to treat right ventricular failure (RVF), in part because RVF molecular drivers have been incompletely studied. We recently identified that the developmentally restricted noncanonical WNT receptor ROR2 is re-expressed in a severity-dependent manner in human RVF. Here we test in mice if, and how, the re-expression of Ror2 causes RVF. Methods/Results: We find in neonatal rat ventricular myocytes (NRVMs) that Ror2 overexpression (Ror2 OE ) both activates protein translation and reduces Hspa1a/b mRNA and Hsp70 protein, resulting in increased protein turnover, fragmented sarcomeres, intercalated disc disruption, reduced cell major axis, impairment of contractile and relaxation kinetics, and ectopy. Ror2 knockdown (Ror2 KD ) results in opposing phenotypes. Hsp70 overexpression or proteasome inhibition rescues many of the Ror2 OE phenotypes, demonstrating their causal involvement. NRVM proteomic analysis indicates that Ror2 OE activates an ERK/p90RSK/Eef2 pathway that is known to regulate translation extension. In vivo, cardiac Ror2 OE in mice causes RV dilation and dysfunction, intercalated disc disruption, reduced Hspa1b (encoding for Hsp70), proteasome activation, and reduced cardiomyocyte ubiquitin staining. The mouse pulmonary artery banding (PAB) model of RVF reveals similar Ror2 induction and proteasome activation. Ror2 KD by AAV9 in PAB reduces RV dilation and improves RV systolic and diastolic function. Finally, in cardiac samples from human RVF, we find evidence for a similar ROR2-responsive proteostatic imbalance with increased proteasome activity and ubiquitin as well as markers of increased ERK and p90RSK. Conclusions: ROR2 is induced in human and mouse RVF, and mechanistic studies in NRVMs and mice show that the induction of ROR2 causes RVF by disrupting the proteostatic balance of translation, folding, and turnover. Knockdown or suppression of ROR2 may serve as a novel RVF therapeutic target.

Patient-Specific Prediction of Immediate Phase Lung Microwave Ablation Zone Size

PurposeTo investigate the effect of patient and tumor-specific characteristics on the size of immediate phase lung microwave ablation (MWA) zone and establish a prediction model. Materials and MethodsThis institutional review board (IRB)–approved, Health Insurance Portability and Accountability Act (HIPAA)–compliant cohort included 164 lesions from 99 patients who underwent computed tomography (CT)–guided lung MWA, and the 2-dimensional elliptical ground-glass opacity ablation zone was measured. Duration, maximum temperature, tumor depth, presence of emphysema, history of ipsilateral lung ablation, surgery, and radiotherapy were recorded. K-fold cross validation with k = 5 and Least Absolute Shrinkage and Selection Operator were used to build prediction models for the major and minor axes and area of the ablation zone. ResultsThe median of immediate phase ablation duration was 2 minutes (interquartile range, 1.5–4.25 minutes) with 65 W of power for all ablations. The mean major and minor axes and area of ablation zone were 3.1 cm (SD ± 0.6), 2.0 cm (SD ± 0.5), and 5.1 cm2 (SD ± 2.1), respectively. The major and minor axes and area of immediate phase ablation zone dimensions were significantly associated with duration (P < .001, P < .001, and P < .001, respectively), maximum temperature (P < .001, P < .001, and P < .001, respectively), tumor depth (P = .387, P < .001, and P < .001, respectively), history of ipsilateral lung ablation (P = .008, P = .286, and P = .076, respectively), and lung radiotherapy (P = .001, P = .042, and P = .015, respectively). The prediction model showed R2 values for major and minor axes and area of the ablation zone to be 0.50, 0.45, and 0.53, respectively. ConclusionsDuration of ablation, maximum temperature, tumor depth, history of ipsilateral lung ablation, surgery, and radiotherapy were significantly associated with the ablation zone dimensions and size and can be used to build the prediction model to approximate the immediate phase lung MWA zone.

Spatially Resolved Analysis of Stellar Populations in NGC 2992: Impact of Active Galactic Nucleus Feedback

In NGC 2992, a galaxy-scale ionized gas outflow driven by active galactic nuclei (AGNs) has long been recognized, yet its impact on the host galaxy has remained elusive. In this paper, we utilize data from the archival Very Large Telescope/MUSE to present a spatially resolved analysis of stellar populations in this galaxy. Two different stellar population templates are employed to fit the stellar continuum, allowing us to determine the light-weighted stellar age, metallicity, the fraction of the young stellar population (age <100 Myr, P Y), and the average age and metallicity of P Y. Our results reveal the presence of a very young stellar population (≤40 Myr) within the dust lane and nearly along the galaxy’s major axis. The light-weighted stellar age and the fraction of P Y show negative trends along the major and minor axes. The average age and metallicity of P Y present positive trends with increasing distance, except along the northern direction of the major axis. Within the circumnuclear region (<1 kpc), the distribution of the young stellar population is spatially anticorrelated with the AGN outflow cone. The highest fraction of P Y is observed at the outskirts of the nuclear radio bubble in the northern region near the nucleus. Considering the coupling efficiency and timescales, we propose that the AGN outflow in this galaxy may exert both negative and positive feedback on its host. Additionally, the star formation and the AGN activities could be attributed to the interaction between NGC 2992 and NGC 2993.

Polar Orbits around the Newly Formed Earth–Moon Binary System

We examine the dynamics and stability of circumbinary particles orbiting around the Earth–Moon binary system. The moon formed close to the Earth (semimajor axis a EM ≈ 3 R ⊕) and expanded through tides to its current day semimajor axis (a EM = 60 R ⊕). Circumbinary orbits that are polar or highly inclined to the Earth–Moon orbit are subject to two competing effects: (i) nodal precession about the Earth–Moon eccentricity vector and (ii) Kozai–Lidov oscillations of eccentricity and inclination driven by the Sun. While we find that there are no stable polar orbits around the Earth–Moon orbit with the current day semimajor axis, polar orbits were stable immediately after the formation of the Moon, at the time when there was a lot of debris around the system, up to when the semimajor axis reached about a EM ≈ 10 R ⊕. We discuss implications of polar orbits on the evolution of the Earth–Moon system and the possibility of polar orbiting moons around exoplanet–moon binaries.

Accuracy of the Measurement of Uterine Leiomyoma by Transabdominal Ultrasonography.

Introduction Uterine leiomyoma is a benign smooth muscle tumor. It does not necessarily require curative treatment, but if conservative management is chosen, it is important to rule out uterine leiomyosarcoma. When a size increase is observed, one must consider malignancy, and thus objective and cost-effective measurement of uterine size is important, especially for early detection of malignant change. Although MRI imaging is thought to be the gold standard for the diagnosis of uterine leiomyosarcoma, frequent MRI is impractical because of the incidence of uterine leiomyoma and the economic burden in real-world clinical practice. On the other hand, ultrasonography (US) is considered the most useful device in the observation of size changes. So this study aimed to examine the accuracy of the measurement of transabdominal US compared to MRI imaging. Materials and methods This retrospective study included 92 patients withuterine myoma ≥ 50 mm who undertook an MRI within 30 days after the transabdominal US. The longest diameter of the largest myoma (a), the longest diameter perpendicular to a in the sagittal image (b), and the longest diameter perpendicular to a and b in the axial image (c) were measured by US and MRI, and these were used to calculate the volume. Results were analyzed by intraclass correlation coefficient (ICC) 3.1. Results The ICC for the volume and major axis of the largest myoma by US and MRI were 0.87 and 0.90, respectively. The 95% confidence intervals (CI) were 0.82-0.91 and 0.87-0.93, respectively. Both reliability levels ranged from good to excellent. ICC was 0.54 (95%CI 0.15-0.78) in myomas with a volume of >500 cm3, and the concordant rate between US and MRI was poor to good. On the other hand, ICC was 0.82 (95%CI 0.57-0.93) even though all myomas with major axes greater than 120 mm had a volume >500 cm3, and the concordant rate between US and MRI measurements was moderate to excellent. In the evaluation by major axis, ICC was 0.60 (95%CI -0.41-0.95) for myomas larger than 160 mm, indicating a lower concordant rate. Conclusion Transabdominal US is an appropriate modality as well as MRI for follow-up of uterine myoma size if the nodules are 160 mm or smaller. Measurement of the major axis is easier and more useful than volume.

Nitrogen Loss from Pluto’s Birth to the Present Day via Atmospheric Escape, Photochemical Destruction, and Impact Erosion

We estimate the loss of nitrogen from Pluto over its lifetime, including the giant planet instability period, which we term the “Wild Years.” We analyze the orbital migration of 53 simulated Plutinos, which are Kuiper Belt Objects (KBOs) captured into 3:2 mean-motion resonance with Neptune during the instability. This orbital migration brought the Plutinos from 20 to 30 au to their present-day orbits near 40 au along a nonlinear path that includes orbits with semimajor axes from 10 to 100 au. We model the thermal history that results from this migration and estimate the volatile loss rates due to the ever-changing thermal environment. Due to the early Sun’s enhanced ultraviolet radiation, the photochemical destruction rate during the Wild Years was a factor of 100 higher than the present-day rate, but this only results in a loss of ∼10 m global equivalent layer (GEL). The enhanced Jeans escape rate varies wildly with time, and a net loss of ∼100 cm GEL is predicted. Additionally, we model the impact history during the migration and find that impacts are a net source, not loss, of N2, contributing ∼100 cm GEL. The 100 cm GEL is 0.1% of the amount of N2 in Sputnik Planitia. We therefore conclude that Pluto did not lose an excessive amount of volatiles during the Wild Years, and its primordial volatile inventory can be approximated as its present-day inventory. However, significant fractions of this small total loss of N2 occurred during the Wild Years, so estimates made using present-day rates will be underestimates.