Local Forces Research Articles

LIDeepDet: Deepfake Detection via Image Decomposition and Advanced Lighting Information Analysis

The proliferation of AI-generated content (AIGC) has empowered non-experts to create highly realistic Deepfake images and videos using user-friendly software, posing significant challenges to the legal system, particularly in criminal investigations, court proceedings, and accident analyses. The absence of reliable Deepfake verification methods threatens the integrity of legal processes. In response, researchers have explored deep forgery detection, proposing various forensic techniques. However, the swift evolution of deep forgery creation and the limited generalizability of current detection methods impede practical application. We introduce a new deep forgery detection method that utilizes image decomposition and lighting inconsistency. By exploiting inherent discrepancies in imaging environments between genuine and fabricated images, this method extracts robust lighting cues and mitigates disturbances from environmental factors, revealing deeper-level alterations. A crucial element is the lighting information feature extractor, designed according to color constancy principles, to identify inconsistencies in lighting conditions. To address lighting variations, we employ a face material feature extractor using Pattern of Local Gravitational Force (PLGF), which selectively processes image patterns with defined convolutional masks to isolate and focus on reflectance coefficients, rich in textural details essential for forgery detection. Utilizing the Lambertian lighting model, we generate lighting direction vectors across frames to provide temporal context for detection. This framework processes RGB images, face reflectance maps, lighting features, and lighting direction vectors as multi-channel inputs, applying a cross-attention mechanism at the feature level to enhance detection accuracy and adaptability. Experimental results show that our proposed method performs exceptionally well and is widely applicable across multiple datasets, underscoring its importance in advancing deep forgery detection.

A mathematical model for wind-generated particle–fluid flow fields with an application to the helicopter cloud problem

We develop a model for the interaction of a fluid flowing above an otherwise static particle bed, with generally the particles being entrained or detrained into the fluid from the upper surface of the particle bed, and thereby forming a fully two phase fluidized cloud above the particle bed. The flow in this large-scale fluidized region is treated as a two-phase flow, whilst the key processes of entrainment and detrainment from the particle bed are treated by examining the local dynamical force balances on the particles in a thin transition layer at the interface between the fully fluidized region and the static particle bed. This detailed consideration leads to the formation of an additional macroscopic boundary condition at this interface, which closes the two-phase flow problem in the bulk fluidized region above. We then introduce an elementary model of the well-known helicopter brownout problem, and use the theory developed in the first part of the paper to fully analyse this model, both analytically and numerically.

High stability of charged particle clusters in protoplanetary disks

Context. The initial particle growth in protoplanetary disks is limited by a bouncing barrier at submillimeter wavelengths. Bouncing leads to tribocharging and the electrostatic attraction of tribocharged aggregates may eventually draw them into large clusters. A charge- mediated growth phase allows for the formation of larger entities, namely, clusters of aggregates that are more prone to further particle concentrations, such as the streaming instability. Aims. We aim to quantify the strength of the electrostatic forces. Methods. In laboratory experiments, we used an acoustic trap to levitate small aggregates of tribocharged submm grains. These aggregates spin up within the trap until they lose grains. Thus, we used the centrifugal force as a measure of the local force. Results. Grains are regularly bound strongly to their neighbors. In comparison, the force at ejection can be stronger than the attractive scattering forces of the trap and can therefore be several orders of magnitude larger than expected. We note that these forces are long- ranging, compared to van der Waals forces. Thus, charged aggregates are much more stable than uncharged ones. Conclusions. Particle aggregates in disks might grow to centimeter clusters or larger as tribocharging increases the effective binding forces. This allows for hydrodynamic concentration and planetesimal formation to eventually take place throughout a wide part of the disk.

Contrasting the role of historic factors in phylogeograpic patterns in the native Johnny darter (Etheostoma nigrum) and invasive round goby (Neogobius melanostomus) in lower michigan.

Round goby (Neogobius melanostomus) is an invasive fish present in all five Great Lakes and is becoming increasingly common in their tributaries. Johnny darter (Etheostoma nigrum) is a native species that often coexists with N. melanostomus. In this work, historic factors are addressed as a source of genomic variation in study populations of these species. To do this, patterns of variation in the mitochondrial gene NADH dehydrogenase subunit 2 (ND2) were characterized for both species throughout Lower Michigan. Populations of N. melanostomus and E. nigrum were sampled from 17 localities representing both eastern and western basins of Lower Michigan to test the hypothesis that populations differ between the eastern and western basins of the Great Lakes. Neogobius melanostomus populations were largely homogenous with no significant differences detected among populations or between the eastern and western basins. Additionally, N. melanostomus exhibited no evidence of overarching historical genetic structure, consistent with the recent invasion and rapid expansion of this species. Etheostoma nigrum exhibited significant differentiation among local populations; however, similarity among mtDNA haplotypes indicated that differences among populations are recent, suggesting that local forces are a more important factor in shaping patterns of variation than historical factors. Contrary to predictions, there were no significant differences detected between the eastern and western basins of the Great Lakes; however, construction of a neighbor-joining tree with F ST estimates revealed clustering of populations by basin with some anomalies. These anomalies may be the result of recent stream capture events facilitating gene flow between the two basins.

On the role of onshore geostrophic flow on larval retention in a permanent upwelling zone along north-central Chile

The Humboldt Archipelago (HAp), located off north-central Chile (~28° - 33° S) is one of the most productive marine zones of the Humboldt Current System (HCS). This area lies within a permanent upwelling zone, characterized by two upwelling centers, 100 km apart, that define the Coquimbo Bays System (CBS). The resulting increase in primary productivity and larval retention are mentioned as the main factors that explain the high biodiversity. However, how these upwelling centers interact remains unclear due to the interplay of various physical features such as the general circulation, the meso- and submeso-scale structures (e.g., eddies), and remote and local forcings (e.g., winds, topography) that affect larval transport in the HAp. In this study, we focus on the role played by geostrophic and Ekman currents in controlling the retention (and dispersion) of particles in these centers based on the analyses of satellite data and hydrodynamic model outputs. Lagrangian models are in particular carried out to document particles’ transport during selected oceanic conditions corresponding to whether Ekman transport or geostrophic recirculation prevails or are debilitated. The latitudinal variation of the Ekman transport reveals two maxima at each upwelling center with differences in spatial extent but not in intensity. Mean zonal geostrophic current occurs in alternating flow at each upwelling center. Results of the Lagrangian experiments highlight the importance of the cross-shore geostrophic flow on larval transport, where an increased transport of particles to the north and northwest occurs at the southern upwelling center, while the northern upwelling center (where HAp is located) received particles from the south and retained particles released in the same area, which is related to the cyclonic geostrophic recirculation and lower Ekman transport. Particle retention increased with depth and under the relaxation and downwelling scenarios revealing the importance of wind alternation for larval retention. The CBS could act as an upwelling shadow in the south and an upwelling trap in the north where the onshore flow of geostrophic current could enhance larval retention and recruitment over longer periods when compared with the Ekman transport timescale.

Latin American networking and cooperative struggles in Argentina: A conversation with the Movimiento de Ocupantes e Inquilinos (MOI)

This conversation examines the Movimiento de Ocupantes e Inquilinos (MOI) in Argentina, a grassroots organization promoting cooperative, self-managed housing for over 30 years. Based on a conversation with Néstor Jeifetz, the article traces the origins of the MOI from the 1980s building occupations in Buenos Aires, through its connection to the broader Latin American cooperative housing movement, including the creation of the Latin American Secretariat for Popular Housing and Habitat (SELVIHP). The article explores how MOI’s efforts to reclaim vacant urban properties—such as the La Fábrica cooperative housing project—address the critical need for secure, affordable housing in a context of neoliberal economic policies and external debt crises. Jeifetz discusses the political ramifications of recent far-right victories in Argentina, which threaten hard-won social rights and self-managed housing initiatives, as well as the MOI’s role in resisting these policies through a framework of collective ownership, democratic decision-making, and mutual aid. By highlighting the intersections of housing with education, health, and labor, and situating the MOI’s work within a larger history of land and building occupations across Abya-Yala, this article provides a nuanced understanding of the ongoing struggles for housing justice in the face of both local and global neoliberal forces.

GLOBAL–LOCAL DRIVING FORCES of CHINA’S GREENING of INDUSTRY

ABSTRACT The greening of industry is an inevitable path for developing economies to achieve sustainability transition. However, the specific roles of global and local driving forces are still not substantially understood. This study develops a three-dimensional framework, which includes coercive pressures, normative pressures, and technology acquisition to analyze the influence of global and local drivers on China’s greening of industry. We measure the industrial eco-efficiency (IEE) using Super-SBM model and analyze its influencing factors using the Tobit regression model at the provincial level in China from 2010 to 2020. China’s IEE evolution and its drivers are stage-specific and regionally differentiated, and differences also exist in the roles of global and local drivers. Developing countries initially start the green development of industry under global normative pressures through integration in the global production network. Thereafter, global coercive pressures and local forces, including domestic technologies, market demands, and effective regulations, drive the further greening of industry. The different potentials of regional coercive and normative pressures depend on industrial structures and socio-technical regimes. Policy recommendations for the greening of industry in developing economies are proposed.

Comparing the Ground Reaction Forces, Toe Clearances, and Stride Lengths of Young and Older Adults Using a Novel Shoe Sensor System

In this study, we developed a lightweight shoe sensor system equipped with four high-capacity, compact triaxial force sensors and an inertial measurement unit. Remarkably, this system enabled measurements of localized three-directional ground reaction forces (GRFs) at each sensor position (heel, first and fifth metatarsal heads, and toe) and estimations of stride length and toe clearance during walking. Compared to conventional optical motion analysis systems, the developed sensor system provided relatively accurate results for stride length and minimum toe clearance. To test the performance of the system, 15 older and 8 young adults were instructed to walk along a straight line while wearing the system. The results reveal that compared to the young adults, older adults exhibited lower localized GRF contributions from the heel and greater localized GRF contribution from the toe and fifth metatarsal locations. Furthermore, the older adults exhibited greater variability in their stride length and smaller toe clearance with greater variability compared to the young adults. These results underscore the effectiveness of the proposed gait analysis system in distinguishing the gait characteristics of young and older adults, potentially replacing traditional motion capture systems and force plates in gait analysis.

Compressed sensing with smooth L0 constraints for moving force identification from bridge response measurements

Abstract Compressed sensing (CS), as an emerging information sampling technique, has been successfully applied in the field of moving force identification (MFI). However, existing MFI CS models often fail to obtain the optimal sparse solutions and frequently underestimate the amplitude of local impact forces. To effectively address this issue, a new CS method is proposed for MFI based on smooth L0 norm constraints and bridge response measurements. Firstly, a smooth function is used to approximate the L0 norm, establishing a noise CS reconstruction model for MFI. The introduction of the smoothing function can locally convexify the original MFI problem and enhance the smoothness and differentiability of the objective function, making the optimization problem easier to solve. Subsequently, the Polak–Ribiere–Polyak formula is adopted to point the descent direction of the new objective function, and the sparse solution is iteratively advanced through the conjugate gradient algorithm. Finally, the applicability and feasibility of the proposed method is confirmed by numerical simulations and vehicle–bridge interaction tests, respectively. The results show that the proposed method can accurately identify moving forces from limited measurements of bridge responses. Compared with existing methods, it can provide more precise sparse solutions with higher robustness to measurement noises, and address the issue of underestimating on the amplitude of local impact forces, which is expected to enhance the performance and in-situ applicability of MFI.

Viscous shear is a key force in Drosophila ventral furrow morphogenesis.

Ventral furrow (VF) formation in Drosophila melanogaster is an important model of epithelial folding. Previous models of VF formation require cell volume conservation to convert apically localized constriction forces into lateral cell elongation and tissue folding. Here, we investigated embryonic morphogenesis in anillin knockdown (scra RNAi) embryos, where basal cell membranes fail to form and therefore cells can lose cytoplasmic volume through their basal side. Surprisingly, the mesoderm elongation and subsequent folding that comprise VF formation occurred essentially normally. We hypothesized that the effects of viscous shear may be sufficient to drive membrane elongation, providing effective volume conservation, and thus driving tissue folding. Since this hypothesis may not be possible to test experimentally, we turned to a computational approach. To test whether viscous shear is a dominant force for morphogenesis in vivo, we developed a 3D computational model incorporating both accurate cell and tissue geometry and experimentally measured material parameters. Results from this model demonstrate that viscous shear generates sufficient force to drive cell elongation and tissue folding in vivo.

British-Armenian Military Relations in Transcaucasia During the Early Stages of the Russian Civil War (1917–1918): A Critical Analysis

This article offers a critical examination of the British-Armenian military relations in Transcaucasia during the early stages of the Russian Civil War (1917-1918), highlighting the complex interplay between British foreign policy, imperial ambitions, and local nationalisms.The plight of the Armenians resonated deeply with the British public and politicians during the First World War. A crucial moment came when the Russian monarchy fell, triggering a complex scenario in Transcaucasia and necessitating a thorough reshuffle of Britain’s foreign and military strategies in the region. In this context, the present study analyses Britain’s political maneuvers and dealings with Armenians in response to the evolving situation in Transcaucasia after the February Revolution. This article shows that notwithstanding the humanitarian ethos that was prevalent in British political rhetoric after the February Revolution in Russia, the strategic undertakings of Britain on the Caucasus front were heavily influenced by its imperial politics and determination to maintain its role in shaping the future of the Middle East and larger Asia. Highlighting the contradictions in British policies toward the region, it argues that these policies were mainly characterized by a colonial mindset that regarded Armenians and other local forces merely as serviceable instruments for realizing a broader imperialist agenda.

Local carotid stiffness, hemodynamic forces and blood viscosity in patients with cerebral lacunar infarctions.

The carotid stiffness is an important factor in the pathogenesis of cerebrovascular small vessel disease. Our study aimed to evaluate the relation of the local arterial stiffness of the common carotid artery (CCA) to the hemodynamic forces and blood viscosity in patients with cerebral lacunar infarctions (LI). Twenty-two patients with chronic LI and 15 age-matched controls were examined. An ultrasound examination of the CCA intima-media thickness (IMT), the parameters of local CCA stiffness: distensibility (DC) and compliance coefficients (CC), α and β stiffness indices and pulse wave velocity (PWV) was performed. The local hemodynamic forces were calculated: circumferential wall tension (CWT) and wall shear stress (WSS). Whole blood viscosity (WBV) and shear stresses at shear rates of 0.277 s-1 to 94.5 s-1 were measured in patients and controls. Higher values of IMT, a significant decrease of DC and CC and an increase of α and β stiffness indices and PWV in the LI patients compared to the controls were obtained. A parallel significant increase in CWT and a decrease in WSS was found. An increase in WBV and a significant increase in shear stresses were detected. In the LI patients, the increased stiffness indices were associated with an increase in age, cholesterol and WBV at higher shear rates in the left CCA. In the controls, the IMT and stiffness indices correlated significantly with the hemodynamic factors and WBV in both CCAs, while the stiffness indices correlated with the hemodynamic forces in the left CCA. The results of the present study demonstrate different associations of the local carotid stiffness indices with the hemodynamic forces and WBV in patients with LI and controls.

Hydrodynamic Mechanism for Stable Spindle Positioning in Meiosis II Oocytes

Cytoplasmic streaming, the persistent flow of fluid inside a cell, induces intracellular transport, which plays a key role in fundamental biological processes. In meiosis II mouse oocytes (developing egg cells) awaiting fertilization, the spindle, which is the protein structure responsible for dividing genetic material in a cell, must maintain its position near the cell cortex (the thin actin network bound to the cell membrane) for many hours. However, the cytoplasmic streaming that accompanies this stable positioning would intuitively appear to destabilize the spindle position. Here, through a combination of numerical and analytical modeling, we reveal a hydrodynamic mechanism for stable spindle positioning beneath the cortical cap. We show that this stability depends critically on the spindle size and the active driving from the cortex and demonstrate that stable spindle positioning can result purely from a hydrodynamic suction force exerted on the spindle by the cytoplasmic flow. Our findings show that local fluid dynamic forces can be sufficient to stabilize the spindle, explaining robustness against perturbations not only perpendicular but also parallel to the cortex. Our results shed light on the importance of cytoplasmic streaming in mammalian meiosis. Published by the American Physical Society 2024

A Review of the Homogenized Lattice Boltzmann Method for Particulate Flow Simulations: From Fundamentals to Applications

The homogenized lattice Boltzmann method (HLBM) has emerged as a flexible computational framework for studying particulate flows, providing a monolithic approach to modeling pure fluid flows and flows through porous media, including moving solid and porous particles, within a unified framework. This paper presents a thorough review of HLBM, elucidating its underlying principles and highlighting its diverse applications to particle-laden flows in various fields as reported in literature. These include studies leading to new fundamental knowledge on the settling of single arbitrarily shaped particles as well as application-oriented research on wall-flow filters, hindered settling, and evaluation of the damage potential during particle transport. Among the strengths of HLBM are its monolithic approach, which allows seamless simulation of different fluid-solid interactions, and its ability to handle arbitrary particle shapes, including irregular and concave geometries, while resolving surface interactions to capture local forces. In addition, its parallel scheme based on the lattice Boltzmann method (LBM) results in high computational efficiency, making it suitable for large-scale simulations, even though LBM requires small time steps. Important future development needs are identified, including the addition of a lubrication force correction model, performance enhancements, such as support for hybrid parallelization and GPU, and the extension of compatible contact models to accommodate concave shapes. These advances promise expanded capabilities for HLBM and broader applicability for solving complex real-world problems.

Operation Interflex: a change in the character of security force assistance?

ABSTRACT The concept of Security Force Assistance (SFA) emerged during the Global War on Terror mainly as a consequence of the increased practice of train, advise, and assist operations. This reflected the situation on the ground in Afghanistan, Iraq, and many African countries in which Western armies trained and assisted local forces in the fight against modern insurgencies. The use of SFA has continued ever since, nevertheless the Russia-Ukraine war has shifted the emphasis of European countries on training the Ukrainian forces for the fight against a conventional opponent. This article explores the consequences of this shift for the character of SFA. Using qualitative data, a comparison is made between the International Security Assistance Force (ISAF) in Afghanistan, and the current application of SFA in the Ukrainian context as embodied in Operation Interflex. Whilst the nature of SFA remains unchanged, the character of SFA changes when used to address regular threats.

Is “Application” Everything about Studying for a University Degree? The Multiple Influences Shaping Undergraduates in Chinese Higher Education in Contemporary Times

Abstract Based on the self-reflection of 22 undergraduate students at a renowned Chinese university regarding their journey towards obtaining a bachelor’s degree, this study reveals the discrepancy between the idealistic functions and missions of higher education as perceived by students and their actual implementations in the real world. It further explores the multifaceted logics exerted by the higher education environment on students during their educational journey. Data analysis shows that contemporary global neoliberalism, alongside traditional Chinese cultural ideologies such as Confucianism and Daoism, significantly impacts the educational philosophies of university students to varying extents. These diverse ideologies drive students to demonstrate varied learning states and behaviors, showcasing the complex interplay of global and local forces in shaping student experiences in higher education.

Cultural Heritage, Migration, and Land Use Transformation in San José Chiltepec, Oaxaca

Indigenous communities worldwide face increasing challenges from modernization, migration, and economic pressures, which threaten their traditional agricultural systems and cultural heritage. These dynamics often lead to shifts in land use, the erosion of ancestral knowledge, and the weakening of cultural identity. Understanding how these communities adapt to such changes is crucial for sustainable development. This research examines how indigenous communities, particularly San José Chiltepec in Oaxaca, balance the preservation of cultural heritage with adapting to evolving agricultural practices and land use transformations. It emphasizes the critical role of indigenous knowledge in sustainable land management and the importance of cultural identity amidst socio-economic pressures. A mixed-methods approach was employed, integrating geostatistical data, spatial analysis, and qualitative insights from municipal development plans and community-based observations. This provided a detailed understanding of how local conditions and external forces shape land use and conservation. The findings reveal that, while irrigated agriculture and pasturelands have declined, the community has shown resilience through the preservation of seasonal farming and the expansion of secondary vegetation. San José Chiltepec serves as a model for how indigenous communities can maintain cultural and environmental heritage while adapting to modern economic challenges.

Crustal seismicity and updated stress mapping in the Bolivian Orocline, Central Andes

The Central Andes region, with significant seismic activity, has distinct faulting mechanisms across its varied topography. Notably, the sub-Andean province predominantly features reverse faulting, whereas the high Andean plateau shows a predominance of normal and strike-slip faults. Despite the importance of this extensive orogenic plateau, Bolivia remains under-documented in seismic studies. We used data from recently installed seismic stations in Bolivia and regional stations in Brazil to determine 13 new focal mechanisms of shallow crustal earthquakes in Bolivia, some of them felt in major cities. Employing probabilistic full waveform moment tensor inversion and P-wave polarities, we mapped the stress distribution across the Central Andes. The main patterns of faulting mechanisms were: reverse faulting along the NW-SE trending sub-Andean belt north of the Orocline (north of Cochabamba) with NE-SW compression; reverse faulting along the N-S trending sub-Andean belt south of the Orocline (south of Santa Cruz) with ∼ E-W oriented compression; strike-slip faulting within the Eastern Cordillera with NE-SW P axes. The results indicate that the sub-Andean belt experiences compressional forces perpendicular to the front of the Andean plateau, arising from both the spreading stresses of the plateau and the broader plate-wide compression. On the other hand, the high plateau (Altiplano) is characterized by normal and strike-slip mechanisms, suggesting a dynamic equilibrium between local extensional gravitational stresses and regional compressional forces due to the Nazca plate convergence.

Arctic climate response to European radiative forcing: a deep learning study on circulation pattern changes

Abstract. Heterogeneous radiative forcing in mid-latitudes, such as that exerted by aerosols, has been found to affect the Arctic climate, though the mechanisms remain debated. In this study, we leverage deep learning (DL) techniques to explore the complex response of the Arctic climate system to local radiative forcing over Europe. We conducted sensitivity experiments using the Max Planck Institute Earth System Model (MPI-ESM1.2) coupled with atmosphere–ocean–land-surface components. Large-scale circulation patterns can mediate the impact of the forcing on Arctic climate dynamics. We employed a DL-based clustering approach to classify large-scale atmospheric circulation patterns. To enhance the analysis of how these patterns impact the Arctic climate, the poleward moist static energy transport (PMSET) associated with the atmospheric circulation patterns was incorporated as an additional similarity metric in the clustering process. Furthermore, we developed a novel method to analyze the circulation patterns' contributions to various climatic parameter anomalies. Our findings indicate that the negative radiative forcing over Europe alters existing circulation patterns and their occurrence frequency without introducing new ones. Specifically, our analysis revealed that while the regional radiative forcing alters the occurrence frequencies of the circulation patterns, these changes are not the primary drivers of the forcing's impact on the Arctic parameters. Instead, it is the shifts in the mean spatial characteristics of the atmospheric circulation patterns, induced by the forcing, that predominantly determine the effects on the Arctic climate. Our methodology facilitates the uncovering of complex, nonlinear interactions within the climate system, capturing nuances that are often obscured in broader seasonal anomaly analyses. This approach enables a deeper understanding of the dynamics driving observed climatic anomalies and their links to specific atmospheric circulation patterns.

Flexoelectronics of a centrosymmetric semiconductor cylindrical nanoshell

Cylindrical shell-type semiconductors are essential for sensing and energy harvesting when integrated into surfaces of certain equipment, such as spacecraft, marine devices, and portable electronics, where mechanical forces play a significant impact on charge transport. Traditionally, such functionalities are only manifested in piezoelectric or pyroelectric crystals that possess non-centrosymmetry. Here, we theoretically investigate electronic behaviors driven by strain gradient-induced flexoelectric polarization in a centrosymmetric semiconductor cylindrical nanoshell, expanding the flexoelectronics in shell structures. The governing equations and accompanying boundary conditions are formulated simultaneously using the principle of virtual work and the fundamental lemma of the calculus of variation. Electromechanical interactions through static bending and forced vibration analyses of the newly developed model are systematically investigated. Under localized force excitation, the distribution of mobile charges is manipulated by tuning loading magnitudes and areas. The effects of doping levels on electric potentials and mobile charges are explored to show the interaction mechanism between flexoelectric and semiconducting properties. Moreover, the natural frequencies and modes of all mechanical displacements, electric potentials, and carrier concentration perturbations within the shell are identified. This paper provides a new approach for designing shell-shaped sensors and energy harvesters specifically for centrosymmetric semiconductors.