Migration Dynamics Research Articles

The Peculiar Consensus and Racial Unconscious in Migration Scholarship on Korea

This paper argues that race must be a central consideration in understanding migration in Korea, where international migrants are rapidly reshaping the national landscape. While migration scholarship on Korea has analyzed various policy trajectories, it has predominantly focused on three aspects—liberal democracy, ethnicity, and gender—largely overlooking the significance of race. First, it assumes that liberal democracy will eventually supersede xenophobia without critically examining its assumptions that are both racialized and teleological in nature. Second, by prioritizing ethnicity, it interprets discrimination against migrants through the notion of uni-ethnicity and a fear of foreignness without delving into Korea’s deeply rooted fixation on race. Third, it overemphasizes gendered migration, regarding Korea’s demographic crisis as a primary reason for accepting migrant women as biological reproducers. This paper contends that all three aspects are intricately connected to race, including Korea’s aspiration for whiteness and abjection of blackness, which significantly shape migration dynamics.

Environmental impact assessment of acidic coal gangue leaching solution on groundwater: a coal gangue pile in Shanxi, China.

With the continual advancement of coal resource development, the comprehensive utilization of coal gangue as a by-product encounters certain constraints. A substantial amount of untreated coal gangue is openly stored, particularly acidic gangue exposed to rainfall. The leaching effect of acidic solutions, containing heavy metal ions and other pollutants, results in environmental challenges such as local soil or groundwater pollution, presenting a significant concern in the current ecological landscape of mining areas. Investigating the migration patterns of pollutants in the soil-groundwater system and elucidating the characteristics of polluted solute migration are imperative. To understand the migration dynamics of pollutants and unveil the features of solute migration, this study focuses on a coal gangue dump in a mining area in Shanxi. Utilizing indoor leaching experiments and soil column migration experiments, a two-dimensional soil-groundwater model is established using the finite element method of COMSOL. This model quantitatively delineates the migration patterns of key pollutant components leached from coal gangue into the groundwater. The findings reveal that sulfate ions can migrate and infiltrate groundwater within a mere 7years in the vadose zone of aeration. Moreover, the average concentration of iron ions in groundwater can reach approximately 58.3mg/L. Convection, hydrodynamic dispersion, and adsorption emerge as the primary factors influencing pollution transport. Understanding the leaching patterns and environmental impacts of major pollutants in acidic coal gangue is crucial for predicting soil-groundwater pollution and implementing effective protective measures.

Adaptive multi-strategy particle swarm optimization for solving NP-hard optimization problems

Particle Swarm Optimization algorithm (PSO) has been widely utilized for addressing optimization problems due to its straightforward implementation and efficiency in tackling various test functions and engineering optimization problems. Nevertheless, PSO encounters issues like premature convergence and a lack of diversity, particularly when confronted with complex high-dimensional optimization tasks. In this study, we propose an enhanced version of the Island Model Particle Swarm Optimization (IMPSO), where island models are integrated into the PSO algorithm based on several migration strategies. The first contribution consists in applying a new selection and replacement strategies based on tabu search technique, while the second contribution consists in proposing a dynamic migration rate relying on the Biogeography-Based Optimization technique. To assess and validate the effectiveness of the proposed method, several unconstrained benchmark functions are applied. The obtained results confirm that the approach yield better performance than the old version of IMPSO for solving NP-hard optimization problems. Compared to the performance of other well-known evolutionary algorithms, the proposed approach is more efficient and effective.

Navigating the Currents: A Comprehensive Exploration of Migration Dynamics and Global Impacts

Migration is a complex and ever-evolving process that impacts societies globally, presenting both positive and negative impacts. The African continent, with its rich history, has been a significant force in migration, driven by exploration, trade, and colonialism. The continent's vastness and diverse regions complicate migration dynamics, with geological factors contributing to the continent's ever-evolving landscape. European migration to Africa is significant, with diverse movements within and outside Africa. The impact of African migration on the global community is profound, affecting labour markets, demographics, and presenting challenges and opportunities. The study advocates for a comprehensive approach to address employment, healthcare, education, and security issues, creating jobs, improving local conditions, and fostering global cooperation to ensure a more equitable and sustainable future. Keywords: Migration dynamics, Globalization and migration, European migration in Africa.

Dynamics of Microcystis surface scum formation under different wind conditions: the role of hydrodynamic processes at the air-water interface.

Due to climate change, Microcystis blooms occur at increasing frequencies in aquatic ecosystems worldwide. Wind-generated turbulence is a crucial environmental stressor that can vertically disperse the Microcystis surface scum, reducing its light availability. Yet, the interactions of Microcystis scum with the wind-generated hydrodynamic processes, particularly those at the air-water interface, remain poorly understood. Here, we explore the response of Microcystis (including colony size and migration dynamics) to varying magnitudes and durations of intermittent wind disturbances in a mesocosm system. The flow velocities, size of Microcystis colonies, and the areal coverage of the water surface by scum were measured through video observations. Our results demonstrate that low wind speeds increase colony size by providing a stable condition where Microcystis forms a scum layer and aggregates into large colonies at the air-water interface. In contrast, wind disturbances disperse scum and generate turbulence, resulting in smaller colonies with higher magnitudes of wind disturbance. We observed that surface scum can form rapidly following a long period (6h) of high-magnitude (4.5m s-1) wind disturbance. Furthermore, our results indicate reduced water surface tension caused by the presence of Microcystis, which can decrease surface flow velocity and counteract wind-driven mixing. The reduced surface tension may also drive lateral convection at the water surface. These findings suggest that Microcystis reduces surface tension, likely by releasing surface-active materials, as an adaptive response to various wind conditions. This could result in an increased rate of surface scum re-formation under wind conditions and potentially facilitate the lateral expansion of scum patches during weak wind periods. This study reveals new insights into how Microcystis copes with different wind conditions and highlights the importance of the air-water interface for Microcystis scum dynamics.

Evaluating the potential of bioacoustics in avian migration research by citizen science and weather radar observations.

The study of nocturnal bird migration brings observational challenges because of reduced visibility and observability of birds at night. Remote sensing tools, especially radars, have long been the preferred choice of scientists to study nocturnal migrations. A major downside of these remote sensing tools is the lack of species-level information. With technological advances in recent decades and with improved accessibility and affordability of acoustic tools, sound recordings have steeply increased in popularity. In Europe, there is no exhaustive qualitative and quantitative evaluation of the content of such acoustic databases and therefore the value for migration science and migration-related applications, such as bird collision hazard assessments, is mostly unknown. In the present work we compared migration schedules estimated from citizen science data with quantitative temporal occurrence of species in four years of acoustic recordings. Furthermore, we contrasted acoustic recordings with citizen science observations and weather radar data from one spring and one autumn season to assess the qualitative and quantitative yield of acoustic recordings for migration-related research and applications. Migration intensity estimated from weather radar data correlated best at low levels with acoustic records including all species in spring while in autumn passerine species showed stronger correlation than the entire species composition. Our findings identify a minor number of species whose call records may be eligible for applications derived from acoustics. Especially the highly vocal species Song thrush and Redwing showed relatively good correlations with radar and citizen science migration schedules. Most long-distance passerine migrants and many other migrants were not captured by acoustics and an estimated seasonal average of about 50% of nocturnally migrating passerine populations remained undetected. Overall, the ability of acoustic records to act as a proxy of overall migration dynamics is highly dependent on the migration period and species involved.

MIGRATION TRENDS AND POLICIES: A REVIEW OF AFRICAN AND USA PERSPECTIVES

Migration is a global phenomenon that significantly shapes the demographic, economic, and social landscapes of nations. This Review provides a concise overview of the migration trends and policies in Africa and the United States, exploring commonalities, differences, and the implications for both regions. In the African context, migration is a multifaceted process influenced by economic, political, and environmental factors. The continent experiences both voluntary economic migration and forced displacement due to conflicts and environmental challenges. This review delves into the diversity of migration policies across African nations, highlighting the tension between regional integration and the need for border controls. The African Union's role in shaping continental migration policies is examined, emphasizing the importance of balancing economic interests with humanitarian considerations. The United States, historically a destination for immigrants, has a complex immigration system shaped by changing societal needs and political landscapes. This Review outlines the various forms of migration to the U.S., including family reunification, employment-based immigration, and asylum-seeking. The dynamic interplay between federal regulations and state-level initiatives contributes to a nuanced policy framework. This review explores the historical evolution of U.S. immigration policies, from periods of openness to more restrictive measures based on economic conditions and security concerns. Comparatively analyzing migration trends and policies in Africa and the USA reveals common themes such as economic aspirations, geopolitical influences on forced migration, and the importance of comprehensive policy frameworks. Recognizing migration as a shared global challenge underscores the need for collaborative approaches. This Review emphasizes the significance of international cooperation to address the root causes of migration, promote economic development, and safeguard the rights of migrants. In conclusion, this Review encapsulates the intricate dynamics of migration in Africa and the USA. By understanding the shared challenges and embracing collaborative solutions, nations can work towards creating more inclusive, humane, and sustainable migration policies that benefit individuals and societies on a global scale.
 Keywords: Perspectives, Policies, USA, Africa, Migration, Review.

Interface engineering and defect passivation for enhanced hole extraction, ion migration, and optimal charge dynamics in both lead-based and lead-free perovskite solar cells

The study elucidates the potential benefits of incorporating a BiI3 interfacial layer into perovskite solar cells (PSCs). Using MAPbI3 and MAGeI3 as active layers, complemented by the robust TiO2 and Spiro-OMeTAD as the charge-transport-layers, we employed the SCAPS-1D simulation tool for our investigations. Remarkably, the introduction of the BiI3 layer at the perovskite-HTL interface significantly enhanced hole extraction and effectively passivated defects. This approach minimized charge recombination and ion migration towards opposite electrodes, thus elevating device performance relative to conventional configurations. The efficiency witnessed a rise from 19.28 to 20.30% for MAPbI3 and from 11.90 to 15.57% for MAGeI3. Additionally, MAGeI3 based PSCs saw an improved fill-factor from 50.36 to 62.85%, and a better Jsc from 13.22 to 14.2 mA/cm2, signifying reduced recombination and improved charge extraction. The FF for MAPbI3 based PSCs saw a minor decline, while the Voc slightly ascended from 1.24 to 1.25 V and Jsc from 20.01 to 21.6 mA/cm2. A thorough evaluation of layer thickness, doping, and temperature further highlighted the critical role of the BiI3 layer for both perovskite variants. Our examination of bandgap alignments in devices with the BiI3 interfacial layer also offers valuable understanding into the mechanisms fueling the observed improvements.

First-Principles Insights into Tungsten Semicarbide-Based Single-Atom Catalysts: Single-Atom Migration and Mechanisms in Oxygen Reduction.

Understanding the structural evolution of single-atom catalysts (SACs) in catalytic reactions is crucial for unraveling their catalytic mechanisms. In this study, we utilize density functional theory calculations to delve into the active phase evolution and the oxygen reduction reaction (ORR) mechanism of tungsten semicarbide-based transition metal SACs (TM1/W2C). The stable crystal phases and optimal surface exposures of W2C are identified by using ab initio atomistic thermodynamics simulations. Focusing on the W-terminated (001) surface, we screen 13 stable TM1/W2C variants, ultimately selecting Pt1/W2C(001) as our primary model. The surface Pourbaix diagram, mapped for this model under ORR conditions, reveals dynamic Pt1 migration on the surface, triggered by surface oxidation. This discovery suggests a novel single-atom evolution pathway. Remarkably, this single-atom migration behavior is also discerned in seven other group VIII SACs, enhancing both their catalytic activity and their stability. Our findings offer insights into the evolution of active phases in SACs, considering substrate structural arrangement, single-atom incorporation, and self-optimization of catalysts under various conditions.

Reconstructing colonization dynamics to establish how human activities transformed island biodiversity

Drivers and dynamics of initial human migrations across individual islands and archipelagos are poorly understood, hampering assessments of subsequent modification of island biodiversity. We developed and tested a new statistical-simulation approach for reconstructing the pattern and pace of human migration across islands at high spatiotemporal resolutions. Using Polynesian colonisation of New Zealand as an example, we show that process-explicit models, informed by archaeological records and spatiotemporal reconstructions of past climates and environments, can provide new and important insights into the patterns and mechanisms of arrival and establishment of people on islands. We find that colonisation of New Zealand required there to have been a single founding population of approximately 500 people, arriving between 1233 and 1257 AD, settling multiple areas, and expanding rapidly over both North and South Islands. These verified spatiotemporal reconstructions of colonisation dynamics provide new opportunities to explore more extensively the potential ecological impacts of human colonisation on New Zealand’s native biota and ecosystems.

Climate-induced migration and gender dynamics in Bangladesh: a social constructivist analysis

ABSTRACT Environmental migration is not a new phenomenon. Climate changes have caused migration from prehistoric times. With climate change exacerbating cyclones and floods, migration from coastal areas to major cities like Dhaka in Bangladesh has become more frequent and severe. This influx poses numerous urban planning challenges. Sometimes, it leads to human trafficking. The focus of this article is to develop a comprehensive understanding of the intricate relationships between gender norms and the availability of rights and opportunities. Women’s migration involves social and psychological effects as well as physical movement. This research examines the social constructivist perspective in the discourse surrounding climate-induced migration.

Flexible construction of heteroatom-free g-C3N4/g-C3N4 homojunction with switching charge dynamics toward efficient photo-piezocatalytic performance

Photo-piezocatalysis based on homojunction emerges as an auspicious approach for the environmental crisis, while it is still in early stage with limited strategies and ambiguous reaction mechanisms. Herein, a heteroatom-free homojunction of ultrathin g-C3N4 with N vacancies/pristine g-C3N4 has been innovatively constructed through surface coupling effect. It achieves higher performance on both photo-piezocatalytic RhB degradation and H2O2 production than solely piezocatalysis or photocatalysis. The underlying causes lie in the synergistic effects of the internal electric field constructed in the type II homojunction and the polarized electric field stimulated by the non-centrosymmetric structure, which cooperatively facilitate the driving force of the charge carriers. Notably, due to the unfixed polarization direction, the charge transfer pathways undergo transitions between type-II and Z-scheme mechanisms, which both promote the spatial separation and migration dynamics of electrons and holes. This work provides new insights into structural design and mechanism exploration for highly efficient photo-piezocatalytic applications.

Computational and experimental approaches into molecular structure mechanism of ZQV coal and the COx gas releases during pyrolysis

Understanding the structural features of coal and its reactive behaviors in thermal processing is the fundamental to achieve high-efficiency utilization of coal. However, the molecular structural features and the evolution characteristics at atomic scales in thermal processing remain unclear in the microscopic views, particularly for the low-rank coals, which usually exhibits high oxygen content with a variety of oxygen-containing organic functional groups and gets lots of CO/CO2 release during pyrolysis. This research provides a comprehensive analysis of the ZaoQuan vitrinite (ZQV) bituminous coal's structural attributes and its pyrolysis-induced reactivity, which is crucial for optimizing the thermal conversion of low-rank coals. The structural parameters characteristics and molecular structures of ZQV have been revealed based on series of materials characterizations and molecular modeling calculations. The single molecular description of ZQV was conceptualized to be C209H132O41N2 under the average molecular approximation, and the particle models with size about 10 nm was also been obtained. Based on the built molecular models, reactive force field molecular dynamics (ReaxFF MD) simulations then provided insights into the dynamic behavior of molecular structures under pyrolysis conditions. Experimental validation corroborates the computational predictions, revealing a strong coherence between observed gas products and those derived from simulation data. Crucially, this study vividly captures the dynamic migration patterns of oxygen-containing groups during coal's thermal decomposition, thus contributing to the understanding of gasification processes. The release mechanisms for CO and CO2 are systematically dissected, proposing three and two distinct pathways respectively. These findings not only consolidate the molecular narrative of coal's structure and pyrolysis reactivity but also serve as a reliable foundation for interpreting the COx evolution of low-rank coals. Our integrated approach propels the scientific comprehension of coal pyrolysis and is anticipated to inform the development of more effective coal utilization pathways and thermal treatment technologies.

For critical geo‐histories of population. Engaging geographically with Massimo Livi Bacci's works

AbstractThis paper aims at calling geographers' attention to the works of Italian historical demographer Massimo Livi Bacci, who authored fundamental texts on the indigenous genocide in the Americas, on the history of world population, on global migrations and on population's environmental ‘sustainability’. In denouncing colonial crimes, critically questioning commonplaces of Malthusian origin and challenging sovereignist prejudices against migrations, Livi Bacci stresses the need for scholars to fully address the complex relations between space and population in both analyses of empirical cases and elaborations of broader theoretical models. He explicitly raises geopolitical matters on the potential political consequences of demographic and migratory dynamics. Yet, Livi Bacci's huge scholarly production is highly influential among historians and demographers, but seems to have been overlooked by most geographers hitherto. For these reasons, I argue that scholars committed to critical, radical and decolonial geographies of population (past and present) should (re)discover Livi Bacci's contributions. Re‐reading Livi Bacci's works through geographical lenses and connecting them with current geographical scholarship, I show how ‘geo‐demography’ can help geographers to address demographic matters at different scales, by providing insights for a new critical geo‐history of population. This interdisciplinary engagement with the relations between geopolitical matters on sustainability and the ongoing changing in global population has the potential to plurally nourish critical geographical agendas, including on global migrations and colonial legacies.

Modification of magnetorheological fluid and its compatibility with metal skeleton: Insights from multi-body dissipative particle dynamics simulations and experimental study

Magnetorheological fluid (MRF), as a smart material, plays a pivotal role in sealing equipment. However, the interfacial compatibility between MRF and metal significantly impacts the adhesion of the two phases, which subsequently determines the sealing performance of MRF once it is used as a sealing medium. However, the interface mechanism and dynamical magnetic migration performances between MRF and metals at the microscopic level are not clear. In this study, dissipative particle dynamics (DPD) and multi-body DPD simulations are carried out to examine the settling stability, static wetting characteristics, and magnetic migration ability of MRF droplets incorporating different surfactants. It is revealed that oleic acid stands out as the optimal surfactant for MRF, shedding light on the mechanism of MRF droplet infiltration on metal sheets and unveiling five crucial wetting processes. Furthermore, a thorough comparison among simulation results, experimental findings, and numerical analysis was conducted to verify the reliability of theoretical research on the microscale behavior of MRF. Moreover, investigating the driving characteristics of MRF droplets within a uniform magnetic field confirmed two driving processes: significant deformation and limitation of excessive diffusion. The analysis of the vortical structure within the droplets revealed the presence of diffusion effects caused by magnetic particles. The velocity distribution within the droplets indicated different flow rates, with higher velocities at the core and slower velocities at the edge, suggesting the presence of internal flow patterns.

Restoring the discontinuous heat equation source using sparse boundary data and dynamic sensors

This study focuses on addressing the inverse source problem associated with the parabolic equation. We rely on sparse boundary flux data as our measurements, which are acquired from a restricted section of the boundary. While it has been established that utilizing sparse boundary flux data can enable source recovery, the presence of a limited number of observation sensors poses a challenge for accurately tracing the inverse quantity of interest. To overcome this limitation, we introduce a sampling algorithm grounded in Langevin dynamics that incorporates dynamic sensors to capture the flux information. Furthermore, we propose and discuss two distinct dynamic sensor migration strategies. Remarkably, our findings demonstrate that even with only two observation sensors at our disposal, it remains feasible to successfully reconstruct the high-dimensional unknown parameters.

An improved transfer coefficient method considering the combined effect of reservoir level variation and rainfall and its application in the stability evaluation of multistage sliding ancient landslides

Abstract In this paper, by considering the dynamic water pressure and particle migration effect caused by reservoir level variation, the weakening effect of slip zone soil influenced by rainfall infiltration, and the interaction force between multistage sliding bodies, an improved transfer coefficient method for multistage sliding ancient landslide is proposed under the combined action of reservoir level variation and rainfall. The results show that (1) the combined action of reservoir level variation and rainfall has a significant influence on the stability of multistage sliding ancient landslides. (2) The sliding force calculated by the improved transfer coefficient method is smaller than the calculation result by the traditional transfer coefficient method, and the residual sliding force is larger. The different sliding body stability coefficient is reduced by about 28.84, 18.13, 19.26, and 21.01%, respectively. (3) The stability results calculated by the traditional transfer coefficient are higher than the improved transfer coefficient method, which may lead to deviation in the multistage sliding ancient landslide stable state judgment. (4) This improved transfer coefficient method can provide a reference for the multistage sliding ancient landslides stability accurate evaluation in hydropower station reservoir area.

Cross Border Migration in India and its Global Implication

Abstract: Cross-border migration is a complex and multifaceted phenomenon with far-reaching implications for nations worldwide. This research paper focuses on examining the dynamics of cross-border migration, using India as a case study to understand its historical roots, current trends, and wide-ranging consequences. The paper begins by providing an overview of the significance of studying global migration patterns and introduces the historical context of cross-border migration in India, shaped by colonial influences and the partition in 1947. Subsequently, the paper delves into contemporary trends in cross-border migration, analysing recent data to find key drivers and motivations behind individuals' decisions to migrate. Economic implications of migration are explored, highlighting both the positive contributions of skilled labour influx and the challenges associated with brain drain and dependency on remittances. Social dynamics of cross-border migration are examined, focusing on cultural diversity, social integration, and the challenges and opportunities presented by cultural shifts. Additionally, the paper addresses environmental factors in migration decisions, considering the implications of climate change on migration patterns. Through case studies, the paper provides a human perspective on cross-border migration, highlighting individual experiences and outcomes. Finally, the paper synthesizes key findings and discusses potential future developments and areas for further research, aiming to contribute to a deeper understanding of the complexities surrounding cross-border migration and its global implications.

An agent-based framework to study forced migration: A case study of Ukraine.

The ongoing Russian aggression against Ukraine has forced over eight million people to migrate out of Ukraine. Understanding the dynamics of forced migration is essential for policy-making and for delivering humanitarian assistance. Existing work is hindered by a reliance on observational data which is only available well after the fact. In this work, we study the efficacy of a data-driven agent-based framework motivated by social and behavioral theory in predicting outflow of migrants as a result of conflict events during the initial phase of the Ukraine war. We discuss policy use cases for the proposed framework by demonstrating how it can leverage refugee demographic details to answer pressing policy questions. We also show how to incorporate conflict forecast scenarios to predict future conflict-induced migration flows. Detailed future migration estimates across various conflict scenarios can both help to reduce policymaker uncertainty and improve allocation and staging of limited humanitarian resources in crisis settings.

Ultrasensitive Flexible Temperature Sensors Based on Thermal-Mediated Ions Migration Dynamics in Asymmetrical Polymer Bilayers.

Accurately acquiring crucial data on the ambient surroundings and physiological processes delivered via subtle temperature fluctuation is vital for advancing artificial intelligence and personal healthcare techniques but is still challenging. Here, we introduce an electrically induced cation injection mechanism based on thermal-mediated ion migration dynamics in an asymmetrical polymer bilayer (APB) composed of nonionic polymer and polyelectrolyte layers, enabling the development of ultrasensitive flexible temperature sensors. The resulting optimized sensor achieves ultrahigh sensitivity, with a thermal index surpassing 10,000 K-1, which allows identifying temperature differences as small as 10 mK with a sensitivity that exceeds 1.5 mK. The mechanism also enables APB sensors to possess good insensitivity to various mechanical deformations─features essential for practical applications. As a proof of concept, we demonstrate the potential impact of APB sensors in various conceptual applications, such as mental tension evaluation, biomimetic thermal tactile, and thermal radiation detection.