Fragmentation Dynamics Research Articles

Exogenous Shocks and Cluster Change in the Howrah Foundries: Dynamics of Conflict and Fragmentation

Exogenous shocks play a crucial role in cluster evolution and change. Yet the mechanisms and processes driving these changes have been relatively underexplored. Furthermore, cluster change studies have focused more on cooperative dynamics. The conflict dynamics in a cluster have received somewhat less attention. Therefore, the present study examines the impact of the exogenous shock on conflicts in a cluster. The Howrah foundry cluster in India constitutes the empirical context of this study. Our findings point to group-level conflict and fragmentation as crucial mechanisms of cluster change. The study further explores the role of rival associations in cluster governance. It shows that rival associations can lead to equitable distribution of opportunities in the cluster. The study also contributes to Indian business history literature. It sheds light on the growth dynamics of small-scale industries and indigenous entrepreneurship in the Howrah district of India. It further brings attention to relatively underexplored data sources in Indian business history.

Assessing Landscape Fragmentation Dynamics with Fourier Transforms

Abstract Quantifying landscape fragmentation is crucial for understanding its impact on biodiversity. Within landscape ecology, there is an ongoing effort to create metrics that systematically characterize landscape patterns and predict their effects on various species. In this study, we utilized Fourier transforms to measure landscape fragmentation in urban and heterogeneous landscapes over periods of 24 and 12 years, respectively. Analyzing Landsat images from 1986, 1999, and 2010, we focused on the first principal component (PC1) to evaluate changes in fragmentation over time. Our analysis revealed a significant increase in fragmentation in urban areas from 1986 to 2010, with a particularly noticeable rise between 1999 and 2010. Specifically, the average Fourier spectrum decreased slightly from 16.0 to 15.9 throughout the study period, indicating increased fragmentation at both urban and landscape levels. The sensitivity analysis further showed that removing 6,000 cells from the original image caused the mean Fourier spectrum to drop from 16.0 to 15.5, demonstrating the method’s effectiveness in detecting subtle land cover changes. Our findings demonstrated that Fourier analysis effectively detects subtle landscape changes, particularly in larger study areas and over longer time intervals. However, it lacks detailed information on specific types or quantities of altered land cover. To address this limitation, integrating Fourier analysis with land cover classification datasets could enhance understanding of landscape dynamics and support more informed conservation and management decisions.

An in-silico study reveals that a C-terminal fragment of the adhesion protein Fibulin7 (Fbln7-C) regulates the activation of integrin α5β1 through dynamics of VWA and the hybrid domain in the β1 subunit

A C-terminal fragment of the adhesion protein Fibulin7 (Fbln7-C) binds to monocytes and neutrophils via integrin α5β1, regulating their adhesion and immunological functions through Erk and STAT signaling pathways. It also inhibits cell binding, spreading, and migration on fibronectin. However, the precise structural components of Fbln7-C that interact with various domains of integrin α5β1 and contribute to its regulatory effects are not entirely understood. This study investigated the structural dynamics of Fibulin7 fragments and the mechanisms by which Fbln7-C regulates α5β1 integrin activation using protein modeling, protein-protein docking, molecular dynamics simulation (MDS), and binding free energy calculations. An energy-minimized model of α5β1 integrin, Fibulin7 full length (Fbln7-FL), and Fbln7-C was developed and validated using 100 ns MDS. Additionally, protein-protein docking was used to confirm Fbln7-C’s better integrin binding ability over Fbln7-FL. A 500 ns MDS on the docked Fbln7-C integrin complex revealed the regulatory effects of Fbln7-C on arginine-glycine-aspartic acid (RGD) bound integrin α5β1. The simulation studies showed that Fbln7-C’s attachment to activated α5β1 integrin increased the distance between the RGD and its interacting residues on both integrin subunits, shifting the RGD ligand from its original binding position and inactivating the integrin. Further analysis using free energy landscape (FEL), principal component analysis (PCA), and binding energy calculation validated the alteration in α5β1 integrin’s structural dynamics following Fbln7-C binding. This could relate to obstruction in the outward swing of the integrin’s hybrid domain and result in the low-affinity, inactive headpiece conformation of the α5β1 integrin.

Realization of Hilbert Space Fragmentation and Fracton Dynamics in Two Dimensions.

We propose the strongly tilted Bose-Hubbard model as a natural platform to explore Hilbert-space fragmentation (HSF) and fracton dynamics in two dimensions in a setup and regime readily accessible in optical lattice experiments. Using a perturbative ansatz, we find HSF when the model is tuned to the resonant limit of on-site interaction and tilted potential. First, we investigate the quench dynamics of this system and observe numerically that the relaxation dynamics strongly depends on the chosen initial state-one of the key signatures of HSF. Second, we identify fractonic excitations with restricted mobility leading to anomalous transport properties. Specifically, we find excitations that show one-dimensional diffusion (z=1/2) as well as excitations that show subdiffusive behavior in two dimensions (z=3/4). Using a cellular automaton, we analyze their dynamics and compare it to an effective hydrodynamic description.

The Dual‐Edged State Paradox: Fighting for Justice When the State is Unreliable

Sociological theories of collective resistance offer insights into how communities mobilize against oppression but often overlook the complexities when the state, an entity relied upon for justice, also acts as an agent of betrayal. Based on 8 years of ethnographic research in Palermo (2016–2024), this study examines the relationship between Sicilian activists and the state, shaped by the dual forces of mafia oppression and state complicity. The present research explores how activists navigate the complexities of collective trauma rooted in state complicity, while simultaneously relying on parts of the state as indispensable allies in their fight for justice. The study introduces the “Dual‐Edged State Paradox,” as a novel framework that captures this contradictory relationship. To navigate the paradox, activists adopt two key strategies: ‘fragmented trust dynamics’ and ‘layered collective resistance’. These strategies illustrate how activists continually recalibrate trust and engage in multi‐layered resistance, adjusting their approach to balance public protest with collaboration based on the positioning of different state actors. This research contributes to our sociological knowledge on collective action, particularly in settings where activists grapple with both external violence of non‐state actors and internal betrayal from the state apparatus.

From local to global: understanding shifts in production processes

ABSTRACT As the global economy continues to integrate, there are notable shifts in how and where products are manufactured. This study examines how increased outward foreign direct investment (FDI) influences shifts in domestic production processes, with a focus on the vertical dimensions of production lines. Using unique Korean firm-level data, we investigate the scope of a firm’s involvement within the production line and the specific stages that have undergone changes. Our findings show that firms with foreign affiliates generally have a narrower scope in their production lines, skewed towards downstream stages – closer to the final stages – compared to firms not engaged in FDI. These micro-level observations are in line with broader trends, such as the decrease in domestic value-added share in gross exports. This study contributes to a more nuanced understanding of FDI’s association with production line modifications, shedding light on the intricate dynamics of global production fragmentation.

Spatiotemporally weighted regression (STWR) for assessing Lyme disease and landscape fragmentation dynamics in Connecticut towns

Understanding the landscape determinants that escalate Lyme disease (LD) risk through various times and regions is vital for appraising disease susceptibility and shaping precise intervention and prevention strategies. This research introduces a novel data-driven framework to identify potential indicators from an extensive array of potential variables. We then deployed an advanced spatiotemporal weighted regression (STWR) model to investigate how landscape fragmentation metrics correlate with the spatiotemporal variability of LD incidence rate in Connecticut towns. We proposed a data-driven filtering framework to select five variables from a large data pool. The analysis unveils that LD incidence rates exhibit heightened sensitivity to proportional or exponential shifts in landscape fragmentation; logarithmic and squared transformations of landscape metrics shed light on lesser effects and venue for potential parabolic relationships. Observations also disclose significant spatial trends, showing elevated LD incidence rates in locales with vast, uninterrupted deciduous forests, alongside contributions from wetland ecosystem-related variables to the rise in disease occurrence. Compared with Geographically Weighted Regression (GWR), the STWR model proved more potent and reliable with higher R2 and lower estimated standard errors (SE). The STWR model is highly flexible in terms of spatiotemporal variations in data. The STWR results further reversely indicate the changes made by the Center for Disease and Prevention (CDC) in the case classification of LD in 2008. The integration of data-driven and model-driven approaches in this study delivers a robust framework that combines empirical pattern detection with theoretical insight, enhancing the robustness and predictive power of ecological studies.

Distinguishing the XUV-induced Coulomb explosion dynamics of iodobenzene using covariance analysis

Abstract The primary and secondary fragmentation dynamics of iodobenzene following its ionization at 120 eV were determined using three-dimensional velocity map imaging and covariance analysis. Site-selective iodine 4d ionization was used to populate a range of excited polycationic parent states, which primarily broke apart at the carbon-iodine bond to produce I+ with phenyl or phenyl-like cations (CnHx + or CnHx 2+, with n = 1-6 and x = 1-5). The molecular products were produced with varying degrees of internal excitation and dehydrogenation, leading to stable and unstable outcomes. This further allowed the secondary dynamics of C6Hx 2+ intermediates to be distinguished using native-frame covariance analysis, which isolated these processes in their own centre-of-mass reference frames. The mass resolution of the imaging mass spectrometer used for these measurements enabled the primary and secondary reaction channels to be specified at the level of individual hydrogen atoms, demonstrating the ability of covariance analysis to comprehensively measure the competing fragmentation channels of aryl cations, including those involving intermediate steps.

QCD predictions for vector boson plus hadron production at the LHC

The identification of a hadron in the final state of hadron-collider events that feature a leptonically decaying vector boson can provide essential information on the parton content of the colliding protons. Moreover, the study of hadrons inside jets can provide deeper insights into the fragmentation dynamics. We provide theoretical predictions for specific observables involving either the production of a Z boson in association with light charged hadrons inside a jet or the production of a W boson together with a charmed hadron. We present results for various fragmentation functions and compare our predictions with measurements by LHCb and ATLAS at s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 13 TeV. Our predictions are obtained using the antenna subtraction formalism which has been extended to cope with infrared singularities associated to the fragmentation processes in a hadron-collider environment at NLO accuracy.

Evolution of Power‐Law Particle‐Size Distributions in Dense Grain‐Flow Experiments

AbstractUnderstanding particle fragmentation and its resulting particle‐size distribution is essential for comprehending shear zone formation, structure, and frictional behavior in faults and landslides, particularly at high normal stresses. 3‐D fractal dimension (D3) is used as a measure of particle‐size distribution, and for the potential self‐similarity physics. Previous research suggests D3 – 2.58 based on the “constrained comminution” model, or D3 = 3.00 considering large shear displacement. However, field data from rock avalanches reveal scattered D3 that deviate from these predictions, possibly due to the neglection of the underlying fragmented physics, such as the particle‐size‐dependent fragmentation probability. Herein, we conducted rotary shear experiments to investigate the evolution of D3 under varying normal stresses, velocities, and mineral compositions. Experimental results demonstrate that D3 monotonically increases with shear displacement and converges to an ultimate value, significantly influenced by mineral composition but less affected by shear velocity and confining stress within the experimental conditions. A modified large‐strain model that considered size‐dependent grain‐breakage probability was proposed, which may explain the observed divergence of D3 from previous predictions. This model highlights the complex mechanisms involved in particle breakage within dense grain‐flows, resulting in the high but scattered D3 observed in natural shear zones. Furthermore, we recognize that additional mechanisms, such as abrasion and grinding, can contribute to the particle size reduction and influence the ultimate fractal dimension. This study provides valuable insights into the dynamics of particle fragmentation in shear zones and has implications for understanding various geological processes.

Catalysis in Extreme Field Environments: A Case Study of Strongly Ionized SiO2 Nanoparticle Surfaces.

High electric fields can significantly alter catalytic environments and the resultant chemical processes. Such fields arise naturally in biological systems but can also be artificially induced through localized nanoscale excitations. Recently, strong field excitation of dielectric nanoparticles has emerged as an avenue for studying catalysis in highly ionized environments, producing extreme electric fields. While the dynamics of laser-driven surface ion emission has been extensively explored, understanding the molecular dynamics leading to fragmentation has remained elusive. Here, we employ a multiscale approach performing nonadiabatic quantum molecular dynamics (NAQMD) simulations on hydrogenated silica surfaces in both bare and wetted environments under field conditions mimicking those of an ionized nanoparticle. Our findings indicate that hole localization drives fragmentation dynamics, leading to surface silanol dissociation within 50 fs and charge transfer-induced water splitting in wetted environments within 150 fs. Further insight into such ultrafast mechanisms is critical for the advancement of catalysis on the surface of charged nanosystems.

Quantum State-Dependent Fragmentation Dynamics of D2S Molecules Following Excitation at Wavelengths ∼ 129.1 and ∼ 139.1 nm.

The first high-resolution translational spectroscopy studies of D atom photoproducts following excitation to the Rydberg states of D2S are reported. Excitation at wavelengths λ ∼ 139.1 nm reveals an unusual 'inverse' isotope effect; the 1B1(3da1←2b1) Rydberg state of D2S predissociates much faster than its counterpart in H2S. This is attributed to accidental near resonance with a vibrationally excited level of a lower-lying, more heavily predissociated Rydberg state of D2S that boosts the probability of nonadiabatic coupling to the dissociation continuum with 1A″ symmetry. Excitation at λ ∼ 129.1 nm populates the 1B1(4da1←2b1) Rydberg state, which predissociates more slowly and allows the study of ways in which the branching into different quantum states of the SD products varies with the choice of parent excited (JKaKc) level. All excited parent levels yield both ground (X) and electronically excited (A) state SD fragments. The former are distributed over a wide range of rovibrational (v″, N″) levels, while the population of levels with low v' and high N' is favored in the latter. These trends reflect the topographies of the dissociative 1A″ (1A') potential energy surfaces that correlate with the respective dissociation limits. Rotational motion about the b-inertial axis in the excited state molecule increases the relative yield of SD(A) products, consistent with dissociation by rotationally (Coriolis-) induced coupling from the photoexcited Rydberg level to the 1A' continuum. Molecules excited to the rotationless (JKaKc = 000) level also yield some SD(A) products, however, confirming the operation of a rival fragmentation pathway wherein photoexcited molecules decay by initial vibronic coupling to the 1A″ continuum, with subsequent nonadiabatic coupling between the 1A″ and 1A' continua enabling access to the D + SD(A) limit.

Three-body deprotonation fragmentation dynamics of C6H63+ induced by electron-impact ionization.

The three-body fragmentation dynamics of benzene trications C6H63+ induced by 200eV electron-impact produced by a photoemission cathode is investigated. All three fragment ions are detected in coincidence, and their momentum vectors are determined by employing a COLTRIMS reaction microscope. The detailed kinematical information of three deprotonation fragmentation channels of H+ + C3H2+ + C3H3+, H+ + C2H3+ + C4H2+, and H+ + C2H2+ + C4H3+ are obtained. By analyzing the momentum and energy correlation spectra among all the three fragment ions, we find that all the three channels are primarily generated by sequential fragmentation processes. Each channel has two deprotonation pathways, corresponding to proton emission in the first or second step of sequential fragmentation, respectively. These results provide insight into the mechanisms and dynamics of deprotonation and ring-breaking reactions in the three-body fragmentation processes of aromatic ring molecules.

Forest fragmentation and forest cover dynamics: Mining induced changes in the West Singhbhum District of Jharkhand

Forests play a crucial role in the global climate system by acting as important carbon storage sinks and controlling the flow of carbon between land and the atmosphere. They provide a wide range of ecosystem services, including the supply of resources and biodiversity conservation. Deforestation is a significant issue leading to the release of carbon dioxide and greenhouse gases. The destruction and fragmentation of existing habitats pose significant threats to biodiversity. This study examined land use/land cover (LULC) alterations in the West Singhbhum district between 1987 and 2021, specifically emphasizing the influence of mining operations on the local forest ecosystem. This study used Landsat satellite imagery to examine data from 1987 to 2021, emphasizing five primary classifications: water body, mining area, built-up areas, open/cropland, and forest/vegetation. The maps were reclassified into two categories, namely, “No-Forest" and “Forest. Forest fragmentation maps were created using Landscape Fragmentation Tool (LFT) v2.0. A regression analysis was conducted to ascertain the correlation between mining growth and the reduction in forest cover. The analysis revealed increased mining areas, developed buildings, and cultivated land accompanied by a decline in forested areas and vegetation. There were substantial changes in land use, with mining areas expanding by 31.14 km2 and open/cropland increasing by 30.39 km2. The conversion of forested areas into agricultural zones and mining regions resulted in a 1.08% reduction in forest coverage.

Fifty-year population trajectory in a marginal American Pika (Ochotona princeps) population

Abstract The American Pika (Ochotona princeps) has been considered a species at risk due to warming temperatures associated with climate change. Many life-history attributes of pikas contribute to the sensitivity of pikas to warming temperatures. Repeated censuses of a marginal (warm, low-elevation) population of pikas at Bodie State Historic Park, California, conducted from 1972 to 2022, are presented to track the population trajectory of pikas for a time period predating recent awareness of global warming to the present day, thus giving a comprehensive portrayal of how American pikas may be responding to climate change. The northern constellation of anthropogenic habitat patches (mine ore dumps) showed no decline in percent of patches occupied or in total number of pika territories over time, suggesting that pikas in that area have not been at risk of extirpation resulting from climate change. In contrast, the pika population in the southern constellation of patches showed significant declines in percent of patches occupied and number of pika territories occupied. That area was unoccupied for about a decade beginning in 2006, but was recently recolonized from the northern constellation of patches. The most likely cause of the initial decline and transient extirpation in the south appears to result from fragmentation and stochastic population dynamics, independent of climatic factors that we investigated. Assessments of climatic impacts on American pikas should take into account the dynamics documented in the Bodie pika population and its resilience over time.

A New Paradigm for Assessing Detailed Dynamics of Forest Landscape Fragmentation

There is an urgent need for a thorough assessment of forest landscape fragmentation to inform forest protection and restoration, and reforestation policies. However, there is currently a lack of an effective comprehensive index for forest landscape fragmentation, and detailed knowledge of the forest landscape fragmentation dynamics remains insufficient. Here, taking Putian City of Fujian Province in Southeastern China as a case, we employed a forest fragmentation comprehensive index (FFCI) to capture key features of forest landscape fragmentation, such as patch size, number, and distribution. Then, bivariate spatial autocorrelation analysis was employed to identify the spatial associations between the static forest landscape fragmentation (FFCI) and the dynamic forest landscape fragmentation (ΔFFCI), and the spatial coupling modes among the three individual components of FFCI (mean patch area, MPA; aggregation index, AI; patch density, PD) were identified to explore the detail process of forest landscape fragmentation. Finally, the random forest model was applied to observe the impact factors of forest landscape fragmentation dynamics. The findings showed that forest landscapes with different degrees of fragmentation exhibited more noticeable changes at both ends (i.e., either high or lower-level fragmentation), with the intermediate level remaining consistent from 2000 to 2020. Around 18.3% of forest landscapes experienced a decrease in fragmentation, particularly in the northern part of the study area, while approximately 81.7% of forest landscapes exhibited an increasing trend in fragmentation. The bivariate spatial autocorrelation analysis indicated that the proportion of Low–High-type grids was the highest at 17.3%, followed by the High–High type at 7.0%. We also identified eight forest landscape fragmentation modes, which indicate the most significant forest landscape fragmentation pattern is a decrease in MPA and an increase in PD. Moreover, the anthropogenic factors (e.g., population density and night light intensity) were found to dominate the FFCI dynamics during 2000–2020. This study offers an efficient research paradigm for the dynamics of forest landscape fragmentation. The outcomes are conducive to an in-depth comprehension of the detailed dynamic information of forest landscape fragmentation, and supply a scientific foundation for enhancing the overall ecological service function of the forest.

Enhanced ballistic resistance of SiC ceramic-fiber composite armor: an investigation of fiber laminate backing effects and fragmentation dynamics

Enhanced ballistic resistance of SiC ceramic-fiber composite armor: an investigation of fiber laminate backing effects and fragmentation dynamics

Semi-Inclusive Deep-Inelastic Scattering at Next-to-Next-to-Leading Order in QCD.

Semi-inclusive hadron production processes in deep-inelastic lepton-nucleon scattering are important probes of the quark flavor structure of the nucleon and of the fragmentation dynamics of quarks into hadrons. We compute the full next-to-next-to-leading order QCD corrections to the coefficient functions for semi-inclusive deep-inelastic scattering in analytical form. The numerical impact of these corrections for precision physics is illustrated by a detailed comparison with data on single inclusive hadron spectra from the CERN COMPASS experiment.

Charge-symmetric and -asymmetric fragmentation dynamics of argon dimers in slow Ar8+–Ar2 collisions

We present an experimental study of multiple-electron capture-induced fragmentation dynamics of Ar2m+ (4 ≤m≤ 7) dimer ions in 4 keV/u Ar8+–Ar2 collisions. The fragment recoil ion pairs and the charge-changing projectiles are coincidentally measured using a double coincidence technique. The branching ratios between the different charge-sharing fragmentation channels show an inherent enhancement of the asymmetric channels. The kinetic energy release (KER) distributions for the associated electron capture process show a shift in the mean KER values toward the higher side with increasing capture stabilization. The interplay between the different projectile autoionization processes sheds light on the energy depositions to the system during collisions. The Coulomb potential energy curves give a physical insight into the role of the projectile final states in the dimer fragmentation dynamics. The dimer-axis orientation-dependent cross sections for the asymmetric fragmentation channels reveal a forward–backward asymmetry that arises from the geometry of the collision system. Our findings thus give insight into the impact parameter-controlled fragmentation dynamics of multiply charged Ar2m+ dimer ions in highly charged ion–dimer slow collisions.

52,000 years of woolly rhinoceros population dynamics reveal extinction mechanisms

The extinction of the woolly rhinoceros (Coelodonta antiquitatis) at the onset of the Holocene remains an enigma, with conflicting evidence regarding its cause and spatiotemporal dynamics. This partly reflects challenges in determining demographic responses of late Quaternary megafauna to climatic and anthropogenic causal drivers with available genetic and paleontological techniques. Here, we show that elucidating mechanisms of ancient extinctions can benefit from a detailed understanding of fine-scale metapopulation dynamics, operating over many millennia. Using an abundant fossil record, ancient DNA, and high-resolution simulation models, we untangle the ecological mechanisms and causal drivers that are likely to have been integral in the decline and later extinction of the woolly rhinoceros. Our 52,000-y reconstruction of distribution-wide metapopulation dynamics supports a pathway to extinction that began long before the Holocene, when the combination of cooling temperatures and low but sustained hunting by humans trapped woolly rhinoceroses in suboptimal habitats along the southern edge of their range. Modeling indicates that this ecological trap intensified after the end of the last ice age, preventing colonization of newly formed suitable habitats, weakening stabilizing metapopulation processes, triggering the extinction of the woolly rhinoceros in the early Holocene. Our findings suggest that fragmentation and resultant metapopulation dynamics should be explicitly considered in explanations of late Quaternary megafauna extinctions, sending a clarion call to the fragility of the remaining large-bodied grazers restricted to disjunct fragments of poor-quality habitat due to anthropogenic environmental change.