Migration Strategies Research Articles

Local community leaders on social resilience to environmental disasters: The case of El Niño in Lurigancho-Chosica in Perú

This study aims to investigate how community leaders of Lurigancho-Chosica, in Lima-Perú, perceive environmental (im)mobility in their community, because of El Niño-Southern Oscillation [ENSO]. ENSO is a recurrent climate event that will likely worsen with rising world temperatures. Lurigancho-Chosica is a highly vulnerable area and one of the most affected by ENSO in the country because of landslides. Using a qualitative approach, interviews were conducted with ten community leaders as key informants from Lurigancho-Chosica to explore their perspectives on the effects of ENSO on their communities and to understand the social resilience of their communities to deal with similar disasters and changes. Findings indicate that, although knowledgeable about the impacts of ENSO, community leaders emphasized that most community inhabitants used multiple coping strategies to deal with the structural limitations of their communities to deal with ENSO. Community leaders themselves opted to strengthen the adaptive capacities of their communities to be more socially resilient, preferring community organization over migration or relocation strategies.

Otoliths as chemical archives through ontogeny reveal distinct migratory strategies of Atlantic halibut within the Gulf of St. Lawrence

Abstract In marine fishes of commercial interest, defining habitat use and migration strategies through ontogeny can help better understand the structure and dynamics of harvested populations and guide their management. The present study relied on otolith chemistry to identify three contingents within the Atlantic halibut (Hippoglossus hippoglossus) stock in the Gulf of St. Lawrence (GSL). We differentiated two chemical signatures from otolith edges, one for shallow (<100 m) and another one for deep (>100 m) waters. By identifying transitions between the deep and shallow habitats, we found that most halibut display migrations from the deep waters to shallow waters during the first 3 years of life. After reaching maturity, most halibut distributing in northern regions of the GSL became full-time residents in deep areas of the GSL. In contrast, halibut found in summer on the shallow plateau of the southern GSL displayed migrating behaviour between shallow (summer) and deep (winter) waters throughout their lives, either on an annual or irregular basis. Overall, our results demonstrate that otolith chemical signatures serve as natural markers of geographically distinct marine environments, facilitating the identification and reconstruction of environmental histories of long-lived marine fishes.

Spatio-temporal migratory patterns, habitat crossing and within-individual movement repeatability of Central Mediterranean European Rollers Coracias garrulus

Populations of long-distance migratory species may exhibit dissimilarities in the leeway of scheduled annual migration programs, the routes they follow and their convergence at ecological barriers. The aim of this study was to fill the current geographical gap, spanning over 1,100 km longitudinally between southern France and eastern Austria, in the pan-European assessment of the migration ecology of the European Roller Coracias garrulus, and contribute to completing the puzzle of spatio-temporal patterns of migration, stopover and wintering at the Western-Palearctic scale for this species. We utilized high-resolution GPS tracking data from adult Rollers breeding in Italy and Croatia, tracked on their intercontinental seasonal journeys between 2018 and 2022 and modelled the variation of migratory components both at individual and population levels. Rollers from the Central Mediterranean exhibited a clockwise spring migration loop, following a Central African migration route and wintering across a wide longitudinal belt spanning from Namibia to Mozambique. Northern savannah zones were used as long stopovers, both in autumn (Chad/Sudan) and spring (Central African Republic/Cameroon). The probability of movement was significantly higher during the night and in spring. Migration speed varied according to season (> in spring) and the habitat crossed (sea > desert > rainforest > savannah). Individuals tracked in successive years showed high consistency of key migratory parameters and partial winter home ranges overlap, in contrast with the large variability of migratory parameters at the population level. This work bridges the current geographical gap of Roller migration ecology at the European level and helps meet conservation needs at the scale of the species’ flyway, with new ecological information valuable for the implementation of International Single Species Action Plans (ISSAP) dedicated to the Roller.Significance statementTracking studies help to disentangle intraspecific variation in migratory strategies and wintering destinations among populations, as well as investigate individual-level decisions taken en route across seasonal journeys. By GPS tracking the intercontinental migration of adult Rollers we found that spatio-temporal components of migratory and flight strategy largely depend on extrinsic factors such as daytime, season and the habitat they traversed, and vary at population level. In contrast, within-individual consistency in migratory and wintering patterns emerged across years. Our findings emphasize the need for effective conservation strategies at the flyway scale.

$E^{2}MS$: An Efficient and Economical Microservice Migration Strategy for Smart Manufacturing

$E^{2}MS$: An Efficient and Economical Microservice Migration Strategy for Smart Manufacturing

Research on the Switch Migration Strategy Based on Global Optimization

Research on the Switch Migration Strategy Based on Global Optimization

Effects of hydraulic cues in barrier environments on fish navigation downstream of dams

Understanding how hydraulic cues in the barrier environment affect fish navigation is critical to fish migration in dammed rivers. However, most of the current research on the effects of hydraulic cues on fish navigation focuses on the effects of a single hydraulic parameter on fish migration and usually ignores fish sensory perception and swimming ability. This study presents an effective approach that combines a computational fluid dynamics model of a river with a model of fish behaviour to elucidate the effects of hydraulic cues in the barrier environment on fish migration paths and strategies by simulating the fish's perception of flow direction and their regulation of multiple hydraulic parameters. Four release scenarios for the dam were reviewed and it was determined that the modelled fish movements realistically reflected actual observations. In various scenarios, the target fish (Schizothorax chongi) managed to move upstream to the tailrace downstream of the dam, despite the hydraulic barrier created by the mainstem area of the river; they overcame this obstacle by exploiting low-velocity zones on both sides of the mainstem and in the river's boundary layer. During upstream movement, the target fish preferred areas with flow velocities between 0.7 and 1.0 m/s and a turbulent kinetic energy of less than 0.3 m2/s2 to maintain aerobic activity. Additionally, the effects of alternative turbine release strategies on the fine-motor movement of target fish were reviewed and an optimised strategy was provided that could increase the proportion of target fish entering the fish passage facility from 0% to 53.8% in the original scenario to 82.6%. This study provides a feasible method for the simulation of fish fine motion in complex flow environments as well as a scientific basis for the management of fish resources in dammed rivers.

A two-level game theoretic approach for task offloading in mobile edge computing

In the mobile edge computing system subject to wireless interference, the Edge Server Provider (ESP) aims to offer profitable computing resources to Device Managers (DMs), who make optimal strategies based on the provided prices. However, the existence of mixed variables typically constitutes an NP-hard problem, posing a significant challenge for optimization. In response to address this issue, we formulate a bi-level optimization problem, where the upper level is devoted to optimizing the pricing of computing resources. The lower level optimizes DM migration strategies and resource allocation at specified prices. Leveraging game theory, we achieve distributed and efficient computation offloading by formulating the distributed computing offloading strategy among lower-level DMs as a task offloading game. Our analysis identifies Nash equilibrium and finite improvement characteristics within the game. Based on these insights, we present a bi-level distributed computation offloading algorithm capable of reaching Nash equilibrium, thus optimizing the profit for both DMs and ESP. The experiments have demonstrated the algorithm’s effectiveness in reducing system costs and maximizing the profits of ESP with DMs across diverse scenarios.

Duration of stay and the integration of migrants: (un)obvious relationships

The article presents the results of a study of the relationship between the duration of stay and the type of migration strategies with various aspects of the integration of migrants from post-Soviet states in Russian society. It is analyzed how at different time intervals (up to 5 years, after 5–10 years, after 10 years from the beginning of migration) improvements occur in status, quality of life, transnational connections (in relation to integration, a decrease in their “density”), language skills, interethnic contacts, the formation of Russian identity among long-term and circular external migrants. A research model is used that includes “relevant conditions” for each integration indicator. The empirical basis of the study was based on data from a nationwide survey of labor migrants conducted by the Center for Ethnopolitical and Regional Studies in 19 constituent entities of the Russian Federation (2017, sample of 7417 respondents). The results of the study show that changes in the status and frequency of interethnic contacts are not associated with duration of stay for either long-term or circular migrants, even when integration conditions are added to the analysis. The “density” of transnational connections changes significantly over time (the peak occurs between 5–10 years after the start of migration, and after 10 years it decreases), however, the interpretation of this connection requires further investigation. “Time” is positively related to such indicators of integration as language skills, quality of life, and identity formation. These connections do not disappear when “relevant conditions” of integration are added to the analysis, however, it is concluded that the duration of stay in itself is not a factor in progress in integration, but acts “together” with the context of migration, the motivation of the actors, their individual capabilities and available resources. resources that determine the trajectory and pace of the integration process.

The role of a non-native forest in the stopover ecology of migratory passerines

During their journey, migratory birds need stopover sites where they can replenish their energy stores. Mosaic forests of agricultural areas, often planted with non-native trees, can provide opportunities for birds to do this. In the present work, I sought to answer the question of the importance of these habitats for migratory birds. For this reason I studied the stopover ecology of 15 species of long- and short-distance migratory passerines. I calculated the minimum stopover duration and the extent of fat accumulation per species and by dividing species into different groups by habitat use and migration distance. For three species, I also estimated their possible flight ranges based on the accumulated fat, body mass and wing length. My results show that the planted oleaster forest has a different role in the stopover habits of the species studied. The body mass of the birds typically did not changed significantly during the time they spent in the area. Forest and farmland species spent the longest time in the area. Despite the possibly high rate of intra- and inter-specific competition, the area can provide sufficient food for birds throughout the whole period. Short-distance migrants stored less fat than long-distance migrants, probably due to the different migration strategies. Flight distances varied according to the migratory habits of the species. From a conservation biology point of view, the study highlighted the role of these habitats in bird migration.

Cooperation within Reason: Tunisia’s Approach to Asylum and Readmission

Abstract Since 2011, migration and asylum have grown in salience in EU-Tunisia international cooperation. Through various agreements, the EU has provided technical and financial support to Tunisia to strengthen its border management capabilities, develop a national migration strategy, legislate a national asylum framework, and re-integrate Tunisians who were returned from Europe. However, among the points of contention between Tunisia and the EU, two key issues stand out: the continued absence of a national law governing asylum in Tunisia, and Tunisia’s refusal to include clauses related to readmission (of its own nationals and third-country nationals) in its agreements with the EU. Drawing on an analysis of cooperation on asylum and readmission between the EU and Tunisia from 2011 to 2021, this article argues that the EU’s perceptions of a lack of cooperation from its Tunisian counterparts are misplaced. Rather, Tunisia is willing to work cooperatively with the EU as long as it does not see this cooperation serve the sole purpose of supporting the EU’s externalization agenda. We see this attitude as a form of resistance to EU pressure, with the unfortunate consequence being the undermining of protection for vulnerable populations in Tunisia and in the EU. Tunisian authorities see the adoption of an asylum law as paving the way for disembarkation platforms, the use of the safe third country concept to return foreign nationals and contain them to Tunisia. This has been fueled by issue linkage in negotiations with the EU between the passing of the asylum act and the return of third-country nationals to Tunisia. Similarly, while Tunisia has concluded agreements with some EU countries regarding the readmission of its nationals, its priorities with respect to facilitating returns lie in the protection of its nationals’ social rights rather than in meeting quantitative targets set by the EU.

Environmental drivers and fitness consequences of partial migration under climate change

Abstract Animals migrate to access seasonally variable resources or to escape unfavorable local conditions. Partial (flexible) migration strategies offer animals a fitness trade-off in which individuals may choose whether to incur the energetic costs of migration depending on the potential benefits associated with avoiding adverse conditions. Partial migration patterns may shift due to anthropogenic land use and climate change, possibly reducing the benefits of migration and resulting in unpredictable migration cues. We examined causes, consequences, and changes in individual-level partial migration of white-tailed deer Odocoileus virginianus by analyzing archival telemetry data (1986-2014) across four distinct populations in the Great Lakes region, North America. We hypothesized that if the costs of migration outweigh benefits, we would see migratory behavior decline. Migratory behavior declined from 75% in 1987 to 11% in 2014 independent of population identity. Annual mortality was higher for migratory white-tailed deer, while increasing minimum temperatures positively impacted survival but did not influence migration. Our results suggest that migratory behavior in white-tailed deer is declining over time and may be associated with declining winter severity. The loss of migratory behavior in large mammals may have ecosystem-level impacts and our study emphasizes the need to better understand and conserve these migratory traditions.

Elucidating the migrations of European seabass from the southern north sea using mark-recapture data, acoustic telemetry and data storage tags

The movement ecology of European seabass, Dicentrarchus labrax, remains poorly understood, especially in the northern ranges of its distribution. To investigate migration patterns of seabass from the southern North Sea, we combined data from different projects from four countries using various tagging techniques. This resulted in 146 recaptures (out of 5598 externally marked seabass), 138 detected animals (out of 162 seabass fitted with an acoustic transmitter) and 76 archived depth and temperature series (out of 323 seabass with an archival tag). Using geolocation modelling, we distinguished different migration strategies, whereby individual fish migrated to the eastern English Channel (15.1%), the western English Channel (28.3%), the Celtic Sea and the norther part of the Bay of Biscay (17.0%), or stayed in the North Sea (39.6%). A high number of seabass exhibited fidelity to the North Sea (90.5% of recaptures, 55.3% for acoustic transmitters and 44.7% of archival tags). Although seabass are generally considered to migrate southwards in winter, a large number of individuals (n = 62) were observed in the southern North Sea, where spawning might potentially occur in a particular deep location along the coast of Norfolk in the UK. Our results highlight the need to consider fine-scaled population structuring in fisheries assessment, and indicate that current seasonal fisheries closures are not aligned with the ecology of seabass in the North Sea.

Review of Cloud Migration Strategies: Exploring Advantages, Challenges and Cost Analysis

Cloud migration has emerged as a strategic im- perative for organizations seeking to leverage the scalability, flexibility, and cost efficiencies offered by cloud computing. This paper presents a comprehensive survey of organizational cloud migration strategies, focusing on the advantages, challenges, and cost analysis associated with this transformative process. The study begins by elucidating the conceptual framework of cloud migration, delineating its fundamental principles and terminolo- gies. Subsequently, it delves into the myriad advantages that com- pel organizations to migrate from on-premises infrastructures to cloud-based solutions. These advantages include enhanced scalability, improved resource utilization, and accelerated time- to-market for new initiatives. However, the migration journey is fraught with challenges, ranging from data security concerns to compatibility issues with legacy systems. This paper meticulously examines these challenges and elucidates strategies employed by organizations to overcome them, thereby ensuring a smooth tran- sition to the cloud. Cost analysis constitutes a pivotal aspect of cloud migration decision-making. This study offers insights into the cost implications associated with various cloud deployment models, such as Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). By conducting a comparative analysis of capital expenditures (CapEx) and op- erational expenditures (OpEx) incurred in both on-premises and cloud environments, organizations can make informed decisions regarding cost optimization and resource allocation. Further- more, the paper explores the critical considerations surrounding data security, regulatory compliance, and vendor selection in the context of cloud migration. Real-world case studies are presented to illustrate successful migration strategies adopted by leading organizations across diverse industries. Keywords —Cloud migration, Cost analysis, Strategies, Re- hosting, Replatforming, Refactoring, Repurchasing, Retiring, Retaining

Mobility-aware SFC migration in dynamic 5G-Edge networks

The fifth-generation mobile networks bring an evolution in the development of novel classes of applications, increasing the demand for performance and flexibility to support new classes of services. Edge Computing and Network Function Virtualization are two key technologies that bring data processing closer to the user and allow the replacement of traditional hardware-based network functions with virtualized counterparts, which reduces costs and permits the provision of low-latency services. In this scenario, services are often implemented as a Service Function Chain (SFC), consisting of a set of ordered Virtual Network Functions (VNFs) that provide the required service functionality. During service execution, users can move from one location to another, which impacts service performance. An approach to reduce the impact of user mobility is to migrate services as users move to different places. However, the SFC migration problem imposes several challenges that require complex decision-making. VNFs should be migrated to nodes that have the necessary resources to execute the VNF instances. Also, the migration should be fast and effective, using as few resources as possible to reduce migration costs. In this paper, we propose a proactive and iterative SFC migration strategy to address the performance impact caused by user mobility. Our proposed solution anticipates the movement of users and estimates the impact of their mobility on service delay, proactively triggering service migrations when needed. The proposed algorithm decides which VNFs of the SFC should be migrated and which compute nodes will host the migrating VNFs, fulfilling service, resource, and migration constraints while maintaining a low migration overhead. Our algorithm also considers the dynamic nature of the edge environment in which other SFC placement and migrations might be occurring when an SFC is being migrated, which also introduces new challenges related to the availability and concurrency of resources required for migration.

Behavioral correlates of migration in bats – do migration strategies predict responses to a novel environment?

Migration is a life-history trait that shapes individual-by-environment interactions, affecting fitness. Currently, many species are changing their migration strategies, stressing the need to identify and better understand the behavioral correlates of migration. As a partial migrant, the noctule bat, Nyctalus noctula, allows for rare intra-specific investigations of the potential behavioral causes (or consequences) of variation in migration. Here, we combined in-situ behavioral assays with stable isotope analyses to investigate whether spatial and acoustic responses to a roost-like novel environment correlate with migration strategy (local or distant). Given a migrant’s more frequent exposure to novel environments, we predicted migrants would enter a novel environment more quickly and show stronger spatial and acoustic exploration activity. However, individuals of local and distant origin did not differ in acoustic exploration (call activity per unit space), nor, contrasting to several bird studies, in spatial activity (number of chambers visited). Surprisingly, local individuals were more likely than migrants to enter the novel environment. Our findings suggest that small-scale exploration does not vary with migration, potentially because of similar selection pressures across migration strategies on small-scale exploration (e.g., exploration of roosts) as opposed to large-scale. Yet, our findings on the likelihood of entering a novel environment suggest that locals may be more risk-taking. Repeated measures would be necessary to determine if personality differences are underlying these responses. Our unique approach, combining behavioral assays with isotopic geolocation, gave us novel insight into an elusive taxon, highlighting the importance of studying behavioral correlates of migration across various taxa.

ISO 20022 : A migration strategy in securities markets for corporate events and triparty collateral management

Anyone involved in processing corporate events and triparty collateral management needs automation and efficiency. A general transition to ISO 20022, the latest messaging standard available, will support further automation across Europe. Its rigorous structure and richer content — compared with the legacy standard ISO 15022 — enables efficient use of collateral across European financial markets and a harmonised process for asset servicing. The Eurosystem and the financial community have developed a Single Collateral Management Rulebook for Europe (SCoRE) setting out how to use ISO 20022. The adoption of this rulebook starts in November 2024 and use of the ISO 20022 format will then become increasingly common. The main issue is how long the legacy standard and local formats should run alongside ISO 20022. Market actors have not yet agreed on how long the transition should last because of a collective coordination problem. The result is a situation where everyone is worse off. To overcome this, a market-wide migration strategy is needed based on cooperation and incentives to define the point from which only ISO 20022 will be used. The Eurosystem is acting as catalyst for a common migration strategy to ISO 20022 because of the benefits it will bring to society.

Empirical Analysis of the Effects of International Labor Migration in EU-27 Countries

Abstract This research aims to provide a critical and comparative analysis of the effects induced by international labor migration in Europe, focusing on specific features and key factors that influence and shape the migration process in the context of the COVID-19 pandemic and geopolitical uncertainty. For conducting a comprehensive study on international labor migration among the member states of the European Union (EU-27), a cross-sectional database of specific migration, labor market, and economic welfare indicators was compiled at the level of 2021. These indicators were subjected to advanced econometric modeling embedding spatial and network analyses processed with the Stata 16 package and the JASP platform to obtain robust and valid results. Main findings of this study provide valuable insights into the evolution and impact of international labor migration, particularly in Romania and the European Union at large. This study serves as a benchmark for future migration strategies by exemplifying the specific characteristics of employees and jobs that will be required in the coming years, while also focusing on identifying the key skills and requirements of both native and migrant employees. Future trends are being analyzed by identifying the characteristics of the modern employee and the professions that will dominate the labor market in the coming years. This will help policymakers appraise migrants’ ability to secure employment in an ever-changing labor market.

Wireless sensor network coverage optimization based on novel multi‐strategy gold rush optimizer

AbstractIn Wireless Sensor Networks (WSN), there are three conflicting important issues, including extensive coverage, low node redundancy, and energy consumption for secondary deployment. To balance network coverage and longevity, a WSN coverage model with three objectives is developed. A novel multi‐strategy gold rush optimizer is proposed for the coverage optimization problem in WSN. First, the fusion search method becomes extensive and flexible by combining the migration strategy with the Levy flight mechanism and joining a follower group. Then, the dynamic opposite learning strategy is used to increase population diversity in the panning stage. In addition, a multi‐player collaborative strategy is utilized to improve search ability of the algorithm in the collaboration stage. Finally, the random differential mutation method is used to try to assist the algorithm in escaping local optima. The simulation results show that this algorithm compared with other algorithms performs better on all three objectives considered.

Geolocation and immersion loggers reveal year‐round residency and facilitate nutrient deposition rate estimation of adult red‐footed boobies in the Chagos Archipelago, tropical Indian Ocean

Bio‐logging has revealed much about high‐latitude seabird migratory strategies, but migratory behaviour in tropical species may differ, with implications for understanding nutrient deposition. Here we use combined light‐level and saltwater immersion loggers to study the year‐round movement behaviour of adult red‐footed boobies Sula sula rubripes from the Chagos Archipelago, tropical Indian Ocean, to assess migratory movements and estimate nutrient deposition rates based on the number of days they spent ashore. Light levels suggest that red‐footed boobies are resident in the Chagos Archipelago year‐round, although there are large latitudinal errors this close to the equator. Immersion data also indicate residency with tracked birds returning to land every one or two days. Spending an average of 79.86 ± 2.80 days and 280.84 ± 2.64 nights per year on land allows us to estimate that the 21 670 pairs of red‐footed boobies deposit 37.34 ± 0.56 tonnes year−1 of guano‐derived nitrogen throughout the archipelago. Our findings have implications for tropical seabird conservation and phylogenetics, as well as for assessing the impact of seabird nutrients on coral reef ecosystems.

Exploring the effectiveness of service migration strategies for virtual network embedding

Network slicing, a key component of post-5G networks, has brought virtual network embedding (VNE) to the forefront of networking research. However, existing VNE approaches are limited by their consideration of static network topologies, failing to account for the dynamic nature of real-world networks. This limitation becomes particularly problematic in the face of link failures or topology modifications, rendering these approaches ineffective. To address this, we propose a new service placement strategy that remains effective even when the network topology changes. Furthermore, we introduce several service migration strategies and thoroughly investigate their effectiveness. Our results demonstrate the adaptability of our proposed strategy, which leverages graph neural networks, in handling link failures without necessitating relearning. This adaptability underlines the potential of our approach to significantly enhance the robustness and flexibility of service migration in VNE, thereby contributing to the evolution of network slicing in post-5G networks.