Abstract In this study, we combine Cassini fields and particle observations to investigate Titan's induced magnetosphere from the TA to T82 flybys, including flybys from the Cassini prime, equinox, and part of the solstice mission, to investigate the average location and the shape of Titan's induced magnetosphere. Although earlier studies have provided valuable information on Titan's induced magnetosphere, they were largely based on separate analyses of fields and particle data. We provide an integrated map of electron density and temperature in Titan's near plasma environment to outline the external boundary of the induced magnetosphere. We identify a dense ionospheric region and an extended plasma wake with electron densities ranging between and c. In addition, we systematize the spatial distribution of pick‐up ions at Titan with respect to the background convective electric field. We indicate that pickup ions are found in the positive hemisphere of the Kronian plasma convective electric field. The mass of the observed pickup corresponds to methane group ions, ions as well as protons and molecular hydrogen ions. The Kronian background electric field progressively accelerates these ions, and we estimate its intensity by reconstructing the radial energy gain of this population in response to the convective electric field. We find the estimated from the pickup ions electric field values within 0.05 mV and 1.92 mV range, which is consistent with an estimate of 0.61 mV deduced from computation.

In this paper, we propose a novel meshless method for shape optimization of sound barriers by combining the Burton-Miller singular boundary method, the isogeometric analysis (IGA), and the particle swarm optimization (PSO). The method addresses th+e spurious frequency issue by introducing the Burton-Miller formulation. The geometric features of sound barriers are accurately described by means of non-uniform rational B-splines, while the PSO algorithm is adopted as the optimization solver. The proposed method only requires the external boundary information of sound barriers. It constructs sound barrier models using NURBS (Non-Uniform Rational B-Splines) and achieves the optimal layout of boundary control points by optimizing the objective function. This method features three distinct advantages: (1) It integrates the IGA technique, enabling the generation of optimization models with only control points; (2) it eliminates the need for sensitivity analysis and avoids tedious mathematical derivations, allowing for the direct shape optimization of sound barriers with complex geometric structures; (3) its numerical calculation process naturally obviates the inherent mesh generation requirement of the finite element method and completely circumvents the common singular integral calculation in the boundary element method. It can seamlessly integrate with computer-aided design systems, bringing convenience to engineers. Numerical experiments confirm its accuracy and effectiveness, showing its obvious advantages as a simple and efficient new way for sound barrier structural optimization design.

ABSTRACT Agricultural policy-based finance (APF) is a crucial component of China’s rural finance system. It implements national agricultural policies and channels funds to key rural areas and vulnerable sectors, which helps increase rural income. We match county branch credit data from the Agricultural Development Bank of China with county-level macroeconomic data and build a panel of about 1453 counties from 2009 to 2018. With this panel, we estimate how APF affects rural residents’ income and test whether government size moderates the effect in a nonlinear way. APF increases income by supporting agricultural product prices, moving labour into non-agricultural employment, improving agricultural productivity, and optimizing agricultural production structure. These effects are larger in counties with higher rural human capital, more advanced digital finance, and looser household registration rules. Government size helps at first. This positive moderation will gradually weaken as the size of the government continues to grow and eventually even reverse, forming an inverted U-shaped pattern. Notably, setting higher economic growth targets weakens this inverted U-shaped moderation. These findings help policymakers clarify APF support’s external validity boundary and effect mechanisms, strengthening its role in rural poverty reduction and common prosperity.

Experimental study on heat feedback mechanism and burning rate of pool fire under the joint limitation of internal and external boundaries

Internal-external boundary attention fusion for glass surface segmentation.

In the present manuscript, we address and solve for the first time a nonlocal discrete isoperimetric problem. We consider indeed a generalization of the classical perimeter, what we call a nonlocal bi-axial discrete perimeter , where not only the external boundary of a polyomino \mathcal{P} contributes to the perimeter, but all internal and external components of \mathcal{P} . Furthermore, we find and characterize its minimizers in the class of polyominoes with fixed area n . Moreover, we explain how the solution of the nonlocal discrete isoperimetric problem is related to the rigorous study of the metastable behavior of a long-range bi-axial Ising model .

ABSTRACTHippocampal subfields differentially develop and age, and they vary in vulnerability to neurodegenerative diseases. Innovation in high‐resolution imaging has accelerated clinical research on human hippocampal subfields, but substantial differences in segmentation protocols impede comparisons of results across laboratories. The Hippocampal Subfields Group (HSG) is an international organization seeking to address this issue by developing a histologically valid, reliable, and freely available segmentation protocol for high‐resolution T2‐weighted 3 T MRI (http://www.hippocampalsubfields.com). Here, we report the first portion of the protocol focused on subfields in the hippocampal body; protocols for the head and tail are in development. The body protocol includes definitions of the internal boundaries between subiculum, Cornu Ammonis (CA) 1–3 subfields, and dentate gyrus, in addition to the external boundaries of the hippocampus apart from surrounding white matter and cerebrospinal fluid. The segmentation protocol is based on a novel histological reference dataset labeled by multiple expert neuroanatomists. With broad participation of the research community, we voted on the segmentation protocol via an online survey, which included detailed protocol information, feasibility testing, demonstration videos, example segmentations, and labeled histology. All boundary definitions were rated as having high clarity and reached consensus agreement by Delphi procedure. The harmonized body protocol yielded high inter‐ and intra‐rater reliability. In the present paper we report the procedures to develop and test the protocol, as well as the detailed procedures for manual segmentation using the harmonized protocol. The harmonized protocol will significantly facilitate cross‐study comparisons and provide increased insight into the structure and function of hippocampal subfields across the lifespan and in neurodegenerative diseases.

Local governments face transboundary collective action dilemmas requiring collaboration across both internal functional and external jurisdictional boundaries. However, limited research addresses how these two collaborative levels interact. Using a national survey of U.S. municipal sustainability efforts, we find strong evidence that the internal organization of local governments significantly impacts their external collaborative networks. Our findings suggest local governments must carefully consider not only whether to dedicate staffing to sustainability, but also where such personnel are housed. This study begins to provide a more holistic theoretical treatment of the internal and external collective action dilemmas inherent to complex transboundary issues.

Abstract We develop a stochastic extension of the Wheeler–DeWitt equation in FLRW minisuperspace and show that quantum backreaction can dynamically regulate the big bang singularity without imposing external boundary conditions. Using Laplace–Beltrami quantisation and an open-system treatment of coarse-grained graviton modes, we obtain a stochastic Hamiltonian evolution equation in which the diffusion coefficient takes the form $\sigma(a)\propto a^2$. This multiplicative noise vanishes at the origin and renders $a=0$ an entrance boundary in Feller’s classification, leading to super-exponential suppression of the Laplace–Beltrami weighted stationary density and zero probability flux into the singular point. At large scale factor, the global behaviour depends on the cosmological sector: de Sitter and positive potential-dominated regimes exhibit power-law stationary tails, whereas confining potentials or negative effective cosmological constant lead to an entrance boundary at infinity and a globally normalizable steady state. Taken together, these results indicate that stochastic backreaction arising from semiclassical coarse-graining provides a consistent and dynamical mechanism for singularity avoidance in minisuperspace quantum cosmology.

Sprinting is a complex skill required in many team and individual sports, with practitioners placing an emphasis on enhancing this aspect of performance to improve sporting success. The task of sprinting involves patterns of inter- and intra-limb coordination and control, which emerge as the athlete accelerates to their maximal velocity. Traditionally, practitioners have attempted to modify sprint coordination patterns from a reductionist or cognitive perspective, decomposing performance to individual component parts using knowledge of coaching literature, biomechanics and skill acquisition theory. However, this approach widely neglects the dynamic and complex interactions that shape sprinting more holistically. This perspective article presents sprint coordination within a dynamical systems theory framework, emphasising how sprint performance emerges from constantly varying internal and/or external boundary conditions that regulate patterns of coordination by controlling mechanical, metabolic and neurophysiological degrees of freedom within the limits of the system. Thereby, movement variability is viewed as an essential component of coordination rather than simply 'noise'. We also review classification schemes that identify stable sprint coordination patterns or strategies, with an emphasis on the acceleration and maximal velocity phases. We then examine practices towards "optimal" sprint technique, plus consider coordinative processes including self-organisation, phase transition and shifts in attractor states, alongside skill acquisition approaches used to establish functional sprint coordination patterns. Ultimately, we aim to present an alternative view for sprint practitioners to consider the complexities of sprint coordination and performance through a dynamical systems lens.

Transpiration cooling is an active thermal protection system in which a coolant is injected through a porous wall into the external boundary layer, where it convects heat from the surface and establishes an insulating film that can also reduce oxidation.Hypersonic vehicles experience extreme aerodynamic heating during ascent, cruise, and re-entry, and conventional thermal protection systems are often non-reusable.Existing studies primarily focus on near-injector behavior and turbulent flows, while research on downstream laminar performance is lacking.This work addresses this gap by numerically simulating the reduction in post-injection heat flux.A steady-state two-dimensional CFD simulation of ideal-gas air at Mach 7 over an isothermal flat plate with a mass-flow inlet is performed in ANSYS Fluent 2025 R1 using a viscous, laminar, pressure-based solver, for six blowing ratios.The uncooled case matches the Eckert reference-enthalpy correlation.Coolant injection reduces wall heat flux downstream, with the thermal effectiveness decaying as the coolant mixes with the freestream flow.At 200 mm downstream, thermal effectiveness varies from 6% to 78% with the blowing ratio.The author proposes a modified correlation.This study supports rapid thermal protection design analysis and identifies areas requiring further validation.

• Novel formulation for inverse finite elastostatics in problems with elastic bed support. • Immerse boundary finite elements framework using hierarchic level-sets to describe the geometry. • The methodology effectively identifies the unloaded configuration of arterial sections. This manuscript presents a novel formulation for inverse finite elastostatics in problems with elastic bed support on the external boundary (elastic bed boundary condition), replacing the classical Dirichlet boundary condition. An unfitted strategy to compute the solution of the mechanical problem is devised, inspired in the Immersed Boundary (IB) framework, and using level sets to describe the geometry. The method is applied to study realistic atherosclerotic arterial sections, which are known to exhibit a pre-stressed configuration. Furthermore, we demonstrate that our method effectively identifies the unloaded configuration. Taking as reference a classical finite elements solver in a commercial code, the method presented results in error lower than 3 % in displacements, for sufficiently fine meshes.

Abstract In this paper, we consider heat and mass transfer in a rectangular multilayer body, where solutions of the 2D equations are connected by internal interface conditions. Similar problems were solved for 1D multilayer body. Here, we focus on an inverse problem (IP) to determine the left and right boundary conditions from integral measured output on the last or the first layer, respectively. In the case of unknown left boundary condition, we begin by reducing the 2D heat problem into 1D problem. This reduction allows us to formulate new 1D IPs within each layer to identify the solution and external left Dirichlet boundary condition. We solve these problems sequentially, moving from the last layer to the first. At the last layer, using the right boundary condition and the integral observation, we find the solution and left Dirichlet and Neumann boundary conditions. Next, from interface conditions, we obtain Dirichlet and Neumann right boundary condition of the preceding layer and solve the IP for identifying its left boundary condition. Following this approach, we advance to the first layer, where we similarly determine the left Dirichlet boundary condition. Well‐posedness both for direct (forward) and IPs is shown. For the numerical solution of the direct and IPs, we construct finite difference schemes. Tikhonov regularization is used for the computation of IPs. Results from computational simulations are presented and discussed.

Early screening for diabetic retinopathy (DR) prevents vision loss in diabetic patients.ObjectiveTo classify DR cases, this study suggests computer-assisted screening and diagnosis. The proposed methodology consists of retinal blood vessel, macular region, and exudate segmentation. In this study, exudates were screened, and DR was classified as mild, moderate, or severe by analyzing the presence of exudates in the macular region.MethodsThe bit-plane morphological slicing technique was employed to segment the macular region. The U-Net deep learning approach was used to segment the exudates from the retinal images, and the proposed methodologies were applied and evaluated on retinal images in the publicly available Methods to Evaluate Segmentation and Indexing Techniques in the field of Retinal Ophthalmology (MESSIDOR) and High-Resolution Fundus (HRF) datasets. Finally, DR can be diagnosed by analyzing the presence of exudates in the macular region, and DR can be diagnosed as mild, moderate, or severe based on the severity levels. The conventional segmentation algorithms segment and locate the internal boundary of pixels in both exudates and macula. In contrast with the conventional segmentation methods, the proposed algorithm segments and locates both internal and external boundary of pixels in both exudates and macula region which increases the segmentation accuracy.ResultsThe proposed macular region segmentation method obtained 98.9% SeI, 99.2% SpI, and 99.1% AccI for the MESSIDOR dataset. The proposed macular region segmentation method obtained 99.2% SeI, 99.7% SpI, and 99.8% AccI for the HRF dataset. The proposed exudate segmentation method obtained 99.3% SeI, 99.2% SpI, and 99.2% AccI for the MESSIDOR dataset. The proposed exudate segmentation method obtained 99.7% SeI, 99.3% SpI, and 99.1% AccI for the HRF dataset.ConclusionThe segmentation time period of both exudates and macula region in retinal image is low when comparing with other segmentation methods. Moreover, this proposed segmentation and diagnosis method was tested with other DIARETDB1, Retinal Fundus Multi-disease Image, and Fundus Image Registration Dataset datasets to validate the effectiveness of the proposed method.

Research on the coupled model of fracturing flowback pollution in fractured systems and wellbore of shale gas development under elastic external boundary conditions.

Computational cost precludes direct numerical simulation or wall-resolved large-eddy simulations of non-equilibrium, wall-bounded turbulent flows in realistic conditions. Wall-modelled large-eddy simulations (WMLES) and hybrid RANS/LES methods can be used to analyse these flows at much decreased cost, but require modelling of the near-wall layer and, in particular, a means to address the deficit of turbulent activity, or eddies, in the vicinity of the interface between the outer flow and the wall model. We report a computational framework to populate the wall region with synthetic but realistic eddies and reflect their integrated effect on the flow in the inner layer. Two means of generating spatio-temporal representations for the synthetic eddies are investigated: low-order, resolvent-based representations of the wall layer and a coarse-grained, data-driven spectral proper orthogonal decomposition (SPOD) model, both generated in turbulent channel flow at a friction Reynolds number, R e τ = 1000 . The eddy-augmented WMLES models are then tested in R e τ = 5000 and 20,000 channels and compared with experimental and numerical data. The inherent scaling of the resolvent operator can be used to scale the resolvent model to higher Reynolds numbers (and potentially populate new, self-similar eddies as the wall layer grows in inner units), while the SPOD model is energetically optimal for reconstruction of the flow at Reynolds numbers close to that where it is obtained, but degrades as the Reynolds number is increased. The results show that the effect of the introduction of synthetic eddies is twofold: first, a direct contribution to the stress due to the presence of the synthetic eddies and, second, an improved prediction of the normal Reynolds stresses in the inner layer due to an accompanying, coupled reduction in the time- and length-scales of the variation of the URANS-like velocity in the inner layer. Implications and extensions of the method for more complex flows, for example external boundary layers with pressure gradient and separation, are briefly discussed. • A method to enrich the near-wall region in WMLES is introduced. • Data-driven and user-driven approaches are used to generate synthetic eddies. • Appropriate choice of the eddy wavenumber and y-support yields improved results. • Future developments of the technique are proposed.

Engineering functional articular cartilage (AC) grafts is one of the greatest challenges in tissue engineering. Recapitulating the arcade-like collagen organisation of AC, which is integral to the tissues’ strength and stiffness, is necessary to engineer truly functional grafts. This motivates the need for innovative strategies to control collagen alignment in engineered tissues in a programmable manner. Emerging 3D bioprinting strategies can provide spatially defined cues to guide tissue growth. Therefore, the goal of this study was to use embedded bioprinting to provide spatially defined boundary conditions to AC progenitor cells (ACP) to direct collagen organization and support the development of biomimetic cartilage tissues. ACPs were isolated through differential adhesion to fibronectin and demonstrated superior chondrogenesis to donor matched chondrocytes. Two different approaches (casting and 3D bioprinting) were used to physically constrain ACPs with external boundaries of differing widths (250, 500, or 750 μm). For both approaches, thinner boundaries promoted greater collagen alignment along the long axis of the developing tissue. Building on this, ACPs were bioprinted into a sheet, with collagen fibers aligning parallel to the print direction. Finally, a multi-layered graft was bioprinted with horizontal filaments (XY plane) overlaying vertical filaments (Z-axis). The bioprinted tissue had an arcade-like collagen organization with horizontal collagen fibres overlaying vertical collagen fibres. These findings demonstrate how support baths can be used to provide spatially defined physical boundary conditions to bioprinted cells to guide matrix organization, enabling the engineering of anisotropic AC grafts.

Over the last decade, numerical simulations and experiments have confirmed the existence of a novel class of vibrationally excited solid-particle attractors in cubic cavities containing a fluid in non-isothermal conditions. The diversity of emerging particle structures, in both morphology and multiplicity, depends strongly on the uni- or multi-directional nature of the imposed temperature gradients. The present study seeks to broaden this theoretical framework by further increasing the complexity of the thermal “information” coded along the external boundary of the fluid container. In particular, in place of the thermal inhomogeneities located in the center of otherwise uniformly cooled or heated walls, here, a cubic cavity with temperature boundary conditions satisfying the D2h (in Schoenflies notation) or “mmm” (in Hermann–Mauguin notation) symmetry is considered. This configuration, equivalent to a bipartite vertex coloring of a cube leading to a total of 24 thermally controlled planar surfaces, possesses three mutually perpendicular twofold rotation axes and inversion symmetry through the cube’s center. To reduce the problem complexity by suppressing potential asymmetries due to fluid-dynamic instabilities of inertial nature, the numerical analysis is carried out under the assumption of dilute particle suspension and one-way solid–liquid phase coupling. The results show that a kaleidoscope of new particle structures is enabled, whose main distinguishing mark is the essentially one-dimensional (filamentary) nature. These show up as physically disjoint or intertwined particle circuits in striking contrast to the single-curvature or double-curvature spatially extended accumulation surfaces reported in earlier investigations.

This study examines the ways Indonesian mothers construct and negotiate family identity through the use of public and private Instagram accounts. The growing presence of mothers on Instagram has transformed the representation of family life into a performative digital practice shaped by visibility, social interaction, and cultural norms. Rather than functioning as a neutral record of everyday experiences, Instagram has become a discursive space where family identity is strategically produced and managed. Drawing on Narrative Performance Theory, this qualitative research employs in-depth interviews with Indonesian mothers who engage in different patterns of digital visibility. The findings indicate that mothers with public Instagram accounts tend to construct curated narratives of family harmony and ideality to achieve social recognition, legitimacy, and broader audience engagement. In contrast, mothers who use private accounts emphasize maternal reflexivity, emotional closeness, ethical responsibility, and the protection of children’s digital privacy. These contrasting narrative practices demonstrate that digital family identity is shaped through internal and external boundary management strategies that balance self-expression, social connection, and digital safety. The study highlights Instagram’s role as a dynamic arena in which family identity is continuously performed, negotiated, and redefined, contributing to broader discussions on digital parenting, family communication, and ethical considerations in social media use.

Purpose Our paper examines how entrepreneurial leadership (EL) impacts firm export innovativeness via digital transformation and supply chain agility. Using the dynamic capability view theory, our paper also explores the moderating impact of leaders’ boundary-spanning behavior on the connection between EL and export innovativeness. Design/methodology/approach To gauge the study hypotheses, time-lagged data were gathered from 244 firms in China. Confirmatory factor analysis was performed to assess the psychometric properties of the measures. The hypothesized links were gauged via the PROCESS macro. Findings Digital transformation and supply chain agility serially mediate the impact of EL on firm export innovativeness. Leaders’ boundary-spanning behavior strengthens the positive effect of EL on digital transformation and supply chain agility, enhancing the drivers of export innovativeness. Practical implications Our study highlights the significance of boosting EL that supports digital innovation and agile supply chains. Encouraging leaders to actively engage across organizational and external boundaries can strengthen these strategic capabilities, ultimately driving export performance and innovation in the global markets. Originality/value Our paper makes a novel contribution by integrating leader boundary-spanning behavior into the connection between EL and firm export innovativeness, a field that has been largely neglected in the pertinent literature. Our paper advances the understanding of how EL fosters export innovativeness through key organizational capabilities, and how this process is shaped by individual-level boundary-spanning behaviors. The framework offers both theoretical insights and practical guidance for firms seeking effective market entry and long-term competitiveness in international markets.