Average Distance Research Articles

The selective consumption of European ivy (Hedera helix) berries by the Common Blackbird (Turdus merula)

Seed dispersal of plants affects the spatial structure and population dynamics, contributing to ecosystem functioning. Birds are among the most important seed dispersers. Preferences of birds in fruit and berry consumption are potentially significant selective pressures on the evolution of fruit traits that affect plant fitness. European ivy (Hedera helix) is a widespread deciduous species in Europe and the Common Blackbird (Turdus merula) is important seed disperser. This study investigates blackbird feeding preferences for specific sizes of ivy seeds. Field data was collected in a small settlement east of Simferopol city in Crimea and included a collection of reference seeds gathered from plants and seeds found in bird excretions. The length of the major axis, minor axis, and aspect ratio were measured, and statistical analysis was performed. The length of the major and minor axes of seeds consumed by blackbirds was higher compared with the reference collection, the aspect ratio was the opposite. Evidence of size differences could suggest weak effect of selective consumption of blackbirds on seed shape. This research extends our knowledge of the ecological relationship between frugivorous birds and plants and the role of birds in directional selection in a particular locality.

Fatigue Crack Propagation Analysis of Rail Surface Under Mixed Initial Crack Patterns

Prolonged rolling contact fatigue between wheels and rails results in the formation of surface cracks on the rail and accurately analyzing the crack expansion behavior is essential to ensuring the safe operation of the train. Drawing upon the principles of fracture mechanics and finite element theory, this study establishes a finite element model of wheel–rail rolling contact that incorporates the presence of cracks. The method utilizes an interaction integral to calculate the stress intensity factors at the leading edge of the crack; then, the Paris formula is used to solve the crack spreading rate. It systematically examines the effects of the initial crack angle, the coefficient of friction of wheels to rails, and crack size on the behavior of fatigue crack propagation. The results indicate that the cracks primarily extend in the depth direction of the rail, transforming the semi-circular surface cracks into elliptical cracks with the major axis oriented along the rail’s width. Crack propagation is primarily driven by model II and III composite crack propagation, with their expansion rates influenced by operating conditions. In contrast, mode-I expansion is less sensitive to these conditions. Under single-variable loading conditions, a smaller initial crack angle results in a faster crack growth rate. Increasing crack length accelerates crack growth, while a higher friction coefficient inhibits it.

Scaling relationships of lamina mass per unit area, mean thickness, and leaf bulk tissue density across nine diverse species.

Although previous studies have reported a positive correlation between leaf dry mass per unit area (LMA) and mean leaf thickness (LT), the LMA versus LT scaling relationship has not been determined due to limited sample sizes, despite its importance in estimating leaf bulk tissue density (mass per unit volume). This issue was addressed using between 174 and 185 leaves from each of nine phylogenetically diverse species to investigate the LMA vs. LT scaling relationship. For each leaf, lamina thickness was measured at 12 positions (avoiding midribs and major veins) to calculate LT, and LMA was measured based on leaf area and dry mass measurements. Reduced major axis regression protocols were used to determine the LMA vs. LT scaling exponent (i.e., the slope). Bootstrap percentile methods were used to calculate the 95% confidence intervals of slopes. A statistically significant LMA vs. LT relationship was found for each species; seven of the nine scaling exponents were significantly greater than unity indicating that LMA (and thus leaf bulk tissue density) disproportionately increased with increasing LT. In addition, the conspecific variation in LMA exceeded the interspecific variation in LMA as a consequence of differences in LT. These results indicate that empirical measurements of LMA and LT can be used to accurately estimate leaf bulk tissue density, which provides insights into adaptive life-history strategies, conspecific variation, and (with sufficiently large data sets) phylogenetic trends.

Lineage-specific intersection of endothelin and GDNF signaling in enteric nervous system development.

Two major ligand-receptor signaling axes - endothelin Edn3 and its receptor Ednrb, and glial-derived neurotrophic factor (GDNF) and its receptor Ret - are required for migration of enteric nervous system (ENS) progenitors to the hindgut. Mutations in either component cause colonic aganglionosis, also called Hirschsprung disease. Here, we have used Wnt1Cre and Pax2Cre in mice to show that these driver lines label distinct ENS lineages during progenitor migration and in their terminal hindgut fates. Both Cre lines result in Hirschsprung disease when combined with conditional Ednrb or conditional Ret alleles. In vitro explant assays and analysis of lineage-labeled mutant embryos show that GDNF but not Edn3 is a migration cue for cells of both lineages. Instead, Edn3-Ednrb function is required in both for GDNF responsiveness albeit in different ways: by expanding the Ret+ population in the Pax2Cre lineage, and by supporting Ret function in Wnt1Cre-derived cells. Our results demonstrate that two distinct lineages of progenitors give rise to the ENS, and that these divergently utilize endothelin signaling to support migration to the hindgut.

Optimal drag-based collision avoidance: Balancing miss distance and orbital decay

The increasing number of objects in Low Earth Orbit makes active collision avoidance imperative for satellites operating in this region. For satellites non equipped with propulsion systems, the collision risk can be mitigated by exploiting the active modulation of aerodynamic forces through the ballistic coefficient. This article proposes a novel and high-fidelity optimal control approach for collision avoidance via aerodynamic drag modulation for an unpropelled SmallSat. Central to this approach is a cost function that jointly maximizes the miss distance while minimizing orbital decay during the maneuver. Moreover, the proposed approach has been rigorously tested through its application to the real-world scenario of the SOURCE satellite, slated for launch in 2025. For the satellite under investigation and a maneuver altitude of 350km, an in-track separation distance of around 22km can be accomplished within a warning time of 24h, which is large enough to conclude that the collision was successfully avoided. As a downside, however, this results in an additional loss in the semi-major axis of 165m and thus a reduced lifetime of the satellite. This balance between separation distance and additional loss in altitude can be flexibly adjusted by the user, which is demonstrated extensively in the article by means of a parameter study. Compared to the widespread use of chemical propulsion systems, this strategy naturally demands longer warning times due to the significantly lower available forces, and also radial offsets to the potential collision object cannot be in this case. Nevertheless, it offers a very promising alternative for active collision avoidance, especially for low-altitude applications.

A Testbed for Tidal Migration: The 3D Architecture of an Eccentric Hot Jupiter HD 118203 b Accompanied by a Possibly Aligned Outer Giant Planet

Characterizing outer companions to hot Jupiters plays a crucial role in deciphering their origins. We present the discovery of a long-period giant planet, HD 118203 c ( mc=11.79−0.63+0.69MJ , ac=6.28−0.11+0.10 au) exterior to a close-in eccentric hot Jupiter HD 118203 b (P b = 6.135 days, m b = 2.14 ± 0.12 M J, r b = 1.14 ± 0.029 R J, e b = 0.31 ± 0.007) based on 20 yr radial velocities (RVs). Using Rossiter–McLaughlin (RM) observations from the Keck Planet Finder, we measured a low sky-projected spin–orbit angle λb=−11°7−10.0+7.6 for HD 118203 b and detected stellar oscillations in the host star, confirming its evolved status. Combining the RM observation with the stellar inclination measurement, we constrained the true spin–orbit angle of HD 118203 b as Ψ b < 33.°5 (2σ), indicating the orbit normal of the hot Jupiter nearly aligned with the stellar spin axis. Furthermore, by combining RVs and Hipparcos-Gaia astrometric acceleration, we constrained the line-of-sight mutual inclination between the hot Jupiter and the outer planet to be 9.°8−9.3+16.2 at the 2σ level. HD 118203 is one of first hot Jupiter systems where both the true spin–orbit angle of the hot Jupiter and the mutual inclination between inner and outer planets have been determined. Our results are consistent with a system-wide alignment, with low mutual inclinations between the outer giant planet, the inner hot Jupiter, and the host star. This alignment, along with the moderate eccentricity of HD 118203 c, implies that the system may have undergone coplanar high-eccentricity tidal migration. Under this framework, our dynamical analysis suggests an initial semimajor axis of 0.3–3.2 au for the proto–hot Jupiter.

An experimental comparative study on condensing supersonic steam jets in water tank: Square, rectangular, and circular cross-sectional shapes

The direct contact condensation phenomenon has gained significant attraction among researchers due to positive aspects such as low driving potential and rapid heat transfer rates in its industrial uses. The present study explores the effect of the cross-sectional shape of converging-diverging on steam-submerged jet condensation behavior. The influence of three cross-sections (circular, square, and rectangular) on steam jet shapes, jet length, average heat transfer coefficient, and maximum expansion ratio were studied. The dimensionless steam jet length for circular, square, and rectangular nozzles has been found in the range of 2.2–7.7, 2.43–8.41, and 2.22–8.35, respectively. The maximum expansion ratio for circular, square, rectangular major axis plane, and rectangular minor axis plane has been found in the range of 1–1.71, 1.14–2.15, 1.22–2.82, and 1.06–1.45. Results show that the maximum expansion ratio and dimensionless jet length rise with steam pressure and water temperature rise. Dimensionless jet length decreases in the order of nozzle with cross-section: square > rectangular > circular. Correlation for dimensional jet length of both circular and non-circular nozzles is presented using the analytical and curve fitting methods. The maximum expansion ratio decreases in order: major axis plane > square > circular > minor axis plane. The average heat transfer coefficient (MW/m2 oC) for circular, square, and rectangular nozzles has been found in the range of 1.16–4.88, 0.89–3.14, and 1.01–3.49. Results show that the average heat transfer coefficient falls with the rise in steam pressure and water temperature. The average heat transfer coefficient decreases in order: circular > rectangular > square. Condensation regime maps are proposed for circular, square, and rectangular nozzles, including diagonal plane effects in square and rectangular nozzle.

Experimental and numerical investigation on the failure behaviors of laminates with various shaped cutouts under tensile loading

Composite structures in aircraft often contain many cutouts, and failure of these structures is prone to occur near the edge of cutouts. Therefore, the failure behaviors of laminates with various shaped cutouts should be carefully investigated. To this end, experiments and numerical simulations are employed to investigate this issue. The tensile tests of composite laminates with circular, elliptical, square, and rectangular cutouts were carried out. Digital image correlation was utilized to capture the strain fields around the cutout. Combining the strain failure criterion and the modified exponential damage variables a three-dimensional progressive damage model was established, which can accurately predict the peak loads of composite laminates with diverse cutouts. All errors between the experimental and numerical results are less than 10 %. The experimental and numerical results indicate that the shape of the cutout has a great influence on the peak loads. As the ratio of major axis to minor axis (a/b) is increased from 1 to 5, peak loads obviously increase for the laminates with elliptical cutouts. Experimental results show that the average peak load of the laminates with elliptical cutout (a/b = 4) is 20.0 % higher than that of the laminates with circular cutout (a/b = 1). The dispersed distribution of high strains near the edge of the cutout results in an improvement of bearing capacity. As the ratio of length to width (l/w) in rectangular cutouts is increased from 0.5 to 3, peak loads are also improved obviously, because experimental results show that the average peak load of the laminates with rectangular cutout (l/w = 0.5) is 12.3 % lower than that of the laminates with square cutout (l/w = 1). Therefore, to improve the peak loads, it is very necessary to select the proper ratios of a/b and l/w. The above conclusions can serve as a reference for the design of composite structures.

Equilibrium dynamical models in the inner region of the Large Magellanic Cloud based on Gaia DR3 kinematics

Context. The Large Magellanic Cloud (LMC) contains complex dynamics driven by both internal and external processes. The external forces are due to tidal interactions with the Small Magellanic Cloud and the Milky Way, while internally its dynamics mainly depend on the stellar, gas, and dark matter mass distributions. Despite this complexity, simple physical models often provide valuable insights into the primary driving factors. Aims. We used Gaia Data Release 3 (DR3) to explore how well equilibrium dynamical models based on the Jeans equations and the Schwarzschild orbit superposition method are able to describe the LMC’s five-dimensional phase-space distribution and line-of-sight (LOS) velocity distribution, respectively. In the Schwarzschild model, we incorporated a triaxial bar component for the first time and derived the LMC’s bar pattern speed. Methods. We fit comprehensive Jeans dynamical models to all Gaia DR3 stars with proper motion and LOS velocity measurements found in the footprint of the VISTA near-infrared survey of the Magellanic System using a discrete maximum likelihood approach. These models are very efficient at discriminating genuine LMC member stars from Milky Way foreground stars and background galaxies. They constrain the shape, orientation, and enclosed mass of the galaxy under the assumption of axisymmetry. We used the Jeans model results as a stepping stone to more complex two-component Schwarzschild models, which include an axisymmetric disc and a co-centric triaxial bar, which we fit to the LMC Gaia DR3 LOS velocity field using a χ2 minimisation approach. Results. The Jeans models describe the rotation and velocity dispersion of the LMC disc well, and we find an inclination angle of θ = 25.5° ±0.2°, line of nodes orientation of ψ = 124° ±0.4°, and an intrinsic thickness of the disc of q0d = b/a = 0.23 ± 0.01 (minor to major axis ratio). However, bound to axisymmetry, these models fail to properly describe the kinematics in the central region of the galaxy dominated by the LMC bar. We used the derived disc orientation and the Gaia DR3 density image of the LMC to obtain the intrinsic shape of the bar. Using these two components as input to our Schwarzschild models, we performed orbit integration and weighting in a rotating reference frame fixed to the bar, deriving an independent measurement of the LMC bar pattern speed of Ω = 11 ± 4 km s−1 kpc−1. Both the Jeans and Schwarzschild models predict the same enclosed mass distribution within a radius of 6.2 kpc of ∼ 1.4 × 1010 M⊙.

Planet Mass Function around M Stars at 1–10 au: A Plethora of Sub-Earth Mass Objects

Small planets (≲1 M ⊕) at intermediate orbital distances (∼1 au) represent an uncharted territory in exoplanetary science. The upcoming microlensing survey by the Nancy Grace Roman Space Telescope will be sensitive to objects as light as Ganymede and unveil the small planet population at 1–10 au. Instrumental sensitivity to such planets is low, and the number of objects we will discover is strongly dependent on the underlying planet mass function. In this work, we provide a physically motivated planet mass function by combining the efficiency of planet formation by pebble accretion with the observed disk mass function. Because the disk mass function for M dwarfs (0.4–0.6 M ⊙) is bottom heavy, the initial planet mass function is also expected to be bottom heavy, skewing toward Ganymede and Mars mass objects, more so for heavier initial planetary seeds. We follow the subsequent dynamical evolution of planetary systems over ∼100 Myr varying the initial eccentricity and orbital spacing. For initial planet separations of ≥3 local disk scale heights, we find that Ganymede and Mars mass planets do not grow significantly by mergers. However, Earth-like planets undergo vigorous merging and turn into super-Earths, potentially creating a gap in the planet mass function at ∼1 M ⊕. Our results demonstrate that the slope of the mass function and the location of the potential gap in the mass function can probe the initial architecture of multiplanet systems. We close by discussing implications on the expected difference between bound and free-floating planet mass functions.

The relationship of changes in insulin demand and insulin adequacy over the life course.

Insulin requirements in the human body undergo continuous changes in response to growth and development. We assessed the life course relationships between insulin demand and insulin adequacy. Three independent Chinese cohorts (204 children, aged [mean ± SD] 7.0 ± 0.5 years; 214 adolescents, aged 15.0 ± 1.8 years; 605 adults, aged 41.5 ± 9.3 years), recruited between 1998 and 2013, underwent OGTT tests. Indices of insulin sensitivity and insulin secretion were calculated based on paired glucose/insulin values during fasting, early phase and late phase of OGTT. Insulin demand and insulin adequacy were calculated by standardised major axis (SMA) regression from the paired insulin sensitivity and secretion indices. We derived the natural logarithm of ratio between the exponential functions of insulin adequacy and insulin demand (RAD) index for further evaluating the relationship between insulin demand and adequacy. The risk of abnormal glucose tolerance (AGT) was evaluated by logistic regression analyses. Area under the receiver-operating characteristic curve (AUC-ROC) analyses, net reclassification improvement (NRI) and integrated discrimination improvement (IDI) indices were used to demonstrate the discriminative value of the RAD method model. Adolescents had the lowest insulin sensitivity and the highest insulin secretion in all phases (fasting, early and late phase) of the OGTT, as compared with children and adults in each phase (all p<0.001). Adolescents had the highest insulin demand in all phases and lowest insulin adequacy in the fasting phase (p<0.001). In general, adults had the lowest insulin adequacy in both the early phase (p>0.05) and late phase (p<0.001) of the OGTT. Adolescents had negative RAD values irrespective of overweight and obesity, while, in general, children and adults had positive RAD values (p<0.001 between age groups in each of the fasting, early and late phases of the OGTT). Participants with RAD values below the 25th percentile had a higher risk of AGT compared with those above the 25th percentile (fasting-phase OR 1.86 [95% CI 1.18, 2.91]; early-phase OR 1.99 [95% CI 1.24, 3.19]; late-phase OR 2.49 [95% CI 1.57, 3.97]). The late-phase RAD index had the best performance in evaluating the risk of AGT compared with the fasting- and early-phase RAD indices (late-phase AUC-ROC = 0.635 [95% CI 0.583, 0.687]; late-phase NRI = 0.350 [95% CI 0.190, 0.510]; late-phase IDI = 0.033 [95% CI 0.015, 0.050]). The relationship between insulin demand and insulin adequacy changed throughout the life course. Adolescents had an imbalanced relationship between insulin demand and insulin adequacy, while, in general, children and adults had a balanced relationship. RAD is a novel index that was used to efficiently describe this relationship and evaluate the risk of AGT.

Convective mixing in distant and close-in giant planets. Dependences on the initial composition, luminosity, bloating, and semi-convection

Recent structure models of Jupiter suggest the existence of an extended region in the deep interior with a high heavy element abundance, referred to as a dilute core. This finding has led to increased interest in modelling the formation and evolution processes with the goal of understanding how and under what circumstances such a structure is formed and retained, to in turn better understand the relation between atmospheric and bulk metallicity. We modelled the evolution of giant planets, varying various parameters relevant for the convective mixing process, such as the mixing length parameter and the size of the mesh, and parameters related to the general evolution, such as the orbital distance and the initial luminosity. We in particular studied hot Jupiters and find that the effect of bloating on the mixing process is small but can in some cases inhibit convective mixing by lowering the intrinsic luminosity for a given entropy. Semi-convection can significantly lower the extent of a dilute core if it is strong enough. We find that dilute cores are unable to persist for initial luminosities much higher than $ 10^3$ L$_J$ for a Jupiter-like planet for the initial heavy element profiles we studied. From this we conclude that, based on our model, it is unlikely that a large number of giant planets retain a dilute core throughout their evolution, although this is dependent on the assumptions and limitations of our method. Future work should focus on improving the link between formation and evolution models so that the mixing process is accurately modelled throughout a planet's lifetime and on improving the understanding of how to model convection near radiative-convective boundaries.

Analyzing the Onset of Cometary Activity by the Jupiter-family Comet 2023 RN3

We utilize serendipitous observations from the Asteroid Terrestrial-impact Last Alert System (ATLAS) and the Zwicky Transient Facility in addition to targeted follow-up observations from the Las Cumbres Observatory (LCO) and Liverpool Telescope to analyze the first observed instance of cometary activity by the newly discovered Jupiter-family comet C/2023 RN3 (ATLAS), whose orbital dynamics place it close to residing on a Centaur-like orbit. Across our 7 month baseline, we observe an epoch of cometary activity commencing in 2023 August with an increase in brightness of >5.4 mag. The lightcurve of 2023 RN3 indicates the presence of continuous cometary activity across our observations, suggesting the onset of a new period of sustained activity. We find no evidence of any outbursts on top of the observed brightening nor do we find any significant color evolution across our observations. 2023 RN3 is visibly extended in LCO and Liverpool Telescope observations, indicating the presence of a spatially extended coma. Numerical integration of 2023 RN3's orbit reveals the comet to have recently undergone a slight increase in semimajor axis due to a planetary encounter with Jupiter; however, whether this orbital change could trigger 2023 RN3's cometary activity is unclear. Our estimate for the maximum dust production metric of Af ρ ∼ 400 cm is consistent with previous measurements for the Jupiter-family comet and Centaur populations.

Hydrodynamic response of a submerged elliptic disc to surface water waves

The impact of an elliptic disc submerged in water of infinite depth on radiation and scattering phenomena is analyzed employing linear water wave theory. The problem is tackled by reducing it into two-dimensional hypersingular integral equations over the surface of the disc. Utilizing a spectral method, where the hypersingularity is evaluated analytically, we obtain numerical solutions for the integral equations. This study presents numerical findings concerning various hydrodynamic parameters relevant to disc scattering and radiation. Initially it compares numerical outcomes with those of a circular disc, before conducting a comprehensive parametric investigation for the elliptic disc. The primary focus is on investigating how the submerged depth and the geometry of the disc impact physical quantities such as added mass, damping coefficient, surface elevation, differential cross-section, and exciting forces. The results reveal a noticeable change in the pressure field around the disc as it approaches the free surface, leading to resonance. Due to the geometry of the submerged rigid elliptic disc, notable alterations in wave profile are noted in the results for both radiation and scattering problems. Furthermore, the radiation problem results reveal significant variations in the added mass and the damping coefficient for non-circular bodies, particularly with a high ratio of the semi-major axis to the semi-minor axis. Overall, this investigation provides a significant benchmark and valuable insights into potential applications in ocean energy and indicates a new design idea of an elliptic base oscillator alongside the commonly used circular designs.

Evidence for a Close-in Tertiary Orbiting around the Algol-type System HZ Dra with Tidal Splitting and Spots Activities

We report a cyclic variation of the O − C diagram with a semiamplitude of 0.0033 days and a period of 1.05 yr for the pulsating eclipsing binary HZ Dra. The cyclic variation can be explained by the light travel-time effect via the presence of a close-in third body orbiting around HZ Dra in an elliptical orbit with a maximum semimajor axis of 0.89 au. Based on the Wilson–Devinney code, the contribution of the third light to the total system is determined to be 29.0%, which is in agreement with the estimated value. Our light-curve modeling indicates an evolving hot and cool spot on the surface of the primary and secondary components, respectively. Their positions are roughly symmetrical to the inner Lagrangian point L1, which could be used to explain the variation in the O'Connell effect. Our frequency analysis detects one radial p-mode, seven nonradial p-modes, and one nonradial g-mode. In addition, a total of six multiplets are identified, spaced by the orbital frequency, which can be explained as a tidally split mode caused by the equilibrium tides of the close binary system with a circular orbit. These pulsating features suggest that the primary of HZ Dra is a δ Scuti star, pulsating in both p- and g-mode and influenced by tidal forces.

Exploring the factors associated with difficulties in extracting tablets or capsules from press-through-package sheets.

Exploring factors related to difficulties in extracting tablets or capsules from press-through-packages is essential for optimizing the dosage form. To achieve this, the involvement of patient insight is important. In the present study, the preferences of patients regarding drugs that are difficult to extract from their packaging were collected using an electronic medication notebook ('harmo®') based on dispensing data. We found that approximately 30% of respondents had difficulty removing tablets or capsules from their packaging, with 125 specific drugs identified as 'hard to push out'. Independent factors related to 'hard-to-push-out' drugs were female sex and feeling of weakness in the hands or fingers. Furthermore, several 'hard-to-push-out' drugs had characteristics such as a spherical shape or small major axis or small major axis drug-to-pocket size ratio. The findings of this study may help improve the quality of drug packaging, thus enhancing the patients' medication experience.

The IMF Clock Angle Effect on the Tail Cross Section of the Martian Magnetic Pileup Boundary and Bow Shock

Using a three-dimensional global magnetohydrodynamic (MHD) simulation model, we investigate the effects of different interplanetary magnetic field (IMF) clock angles on the tail configuration of the Martian magnetic pileup boundary (MPB) and bow shock (BS). The study reveals the following: (1) The cross sections of the tail MPB and BS are approximately elliptical. The MPB tail cross section generally elongates in the direction of the IMF clock angle, whereas the BS tail cross section is roughly elongated perpendicular to the IMF clock angle direction. (2) An IMF with a northward component can cause the tail cross section of the MPB to shift slightly to the south when the intense crustal magnetic fields are located on the dayside. (3) As the tail distance from Mars increases, the eccentricity of the cross section ellipses of both the MPB and BS tail increases, as well as the major and minor axes. Additionally, the major and minor axes of the tail MPB’s cross section ellipses begin to decrease at the far magnetotail, suggesting that the Martian MPB tail might be a closed structure on the nightside.

Inhibition of IRE1α/XBP1 axis alleviates LPS-induced acute lung injury by suppressing TXNIP/NLRP3 inflammasome activation and ERK/p65 signaling pathway

BackgroundAcute lung injury or acute respiratory distress syndrome (ALI/ARDS) is a devastating clinical syndrome with high incidence and mortality rates. IRE1α-XBP1 pathway is one of the three major signaling axes of endoplasmic reticulum stress that is involved in inflammation, metabolism, and immunity. The role and potential mechanisms of IRE1α-XBP1 axis in ALI/ARDS has not well understood.MethodsThe ALI murine model was established by intratracheal administration of lipopolysaccharide (LPS). Hematoxylin and eosin (H&E) staining and analysis of bronchoalveolar lavage fluid (BALF) were used to evaluate degree of lung injury. Inflammatory responses were assessed by ELISA and RT-PCR. Apoptosis was evaluated using TUNEL staining and western blot. Moreover, western blot, immunohistochemistry, and immunofluorescence were applied to test expression of IRE1α, XBP1, NLRP3, TXNIP, IL-1β, ERK1/2 and NF-κB p65.ResultsThe expression of IRE1α significantly increased after 24 h of LPS treatment. Inhibition of the IRE1α-XBP1 axis with 4µ8C notably improved LPS-induced lung injury and inflammatory infiltration, reduced the levels of IL-6, IL-1β, and TNF-α, and decreased cell apoptosis as well as the activation of the NLRP3 inflammasome. Besides, in LPS-stimulated Beas-2B cells, both 4µ8C and knockdown of XBP1 diminished the mRNA levels of IL-6 and IL-1B, inhibited cell apoptosis and reduced the protein levels of TXNIP, NLRP3 and secreted IL-1β. Mechanically, the phosphorylation and nuclear translocation of ERK1/2 and p65 were significantly suppressed by 4µ8C and XBP1 knockdown.ConclusionsIn summary, our findings suggest that IRE1α-XBP1 axis is crucial in the pathogenesis of ALI/ARDS, whose suppression could mitigate the pulmonary inflammatory response and cell apoptosis in ALI through the TXNIP/NLRP3 inflammasome and ERK/p65 signaling pathway. Our study may provide new evidence that IRE1α-XBP1 may be a promising therapeutic target for ALI/ARDS.

A New Rarity Assessment of the “Disk of Satellites”: The Milky Way System Is the Exception Rather Than the Rule in the ΛCDM Cosmology

The majority of satellite galaxies around the Milky Way (MW) show disk-like distributions (the disk of satellites; DoS), which is a small-scale problem of the lambda cold dark matter cosmology. The conventional definition of the MW-like DoS is a satellite system with a minor-to-major axis ratio (c/a) lower than the MW’s c/a value of 0.181. Here, we question the validity of the c/a-based DoS rarity assessment and propose an alternative approach. How satellites are placed around a galaxy is dictated mainly by two factors: the distributions of the satellites’ orbital poles and their distances from the host. Based on this premise, we construct the “satellite distribution generator” code and generate 105 spatially and kinematically analogous systems (SKASs) sharing these two factors. The SKAS can disclose the intrinsic, underlying c/a probability distribution function (PDF), from which a present-day c/a value is fortuitously determined. We find that the c/a PDF of the MW DoS defined by 11 classical satellites is quite broad (σ c/a ∼ 0.105), implying that a simple present-day c/a value, combined with its highly time-variable nature, cannot fully represent the degree of flatness. Moreover, based on the intrinsic c/a PDF, we reevaluate the rarity of the MW DoS by comparing it with Illustris TNG50-1 host–satellite systems and find that even with the new measure, the MW DoS remains rare (0.00%–3.40%). We show that the reason behind the rareness is that both orbital poles and distances of the 11 MW satellites are far more plane-friendly than those of simulated host–satellite systems, challenging the current structure and galaxy formation model.

Lagrange’s planetary equations with time-dependent secular perturbations

The long-term evolution of quasi-Keplerian systems is driven by a Hamiltonian that is independent of the fast angle. As this Hamiltonian may contain explicitly time-dependent parameters, the conservation of mechanical energy is not guaranteed in such systems. We derive how the semi-major axis evolves in these cases. We analyze two astrophysically interesting examples, those of the harmonic and quadrupole perturbations.