arXiv subjects

Rafael Prieto-Curiel

Publications and source records attributed to Rafael Prieto-Curiel.

At least 19 recordsLinked to original sources

arXiv2026

Debt relief and remittances can offset foreign aid cuts for most countries, but some remain locked out

In 2025, bilateral foreign aid was reduced by 23%, affecting more than 130 aid recipient countries. We assess whether debt service relief or remittance increases can match the USD 26 billion in aid losses. Using a network-shock model calibrated to bilateral donors' individual cuts, we estimate recipient-country aid losses and evaluate compensation feasibility in terms of annual debt service payments that would need to be cancelled and remittance capacity (the headroom between flows and a theoretical maximum in which every working-age migrant sends funds) mobilised to financially offset them. We find that 18% external debt service relief and 10% of remittance mobilisation could compensate half of the affected countries. However, some countries remain locked out of either or both mechanisms. A fundamental trade-off in the global financial architecture emerged for large aid-cut losers: countries positioned to benefit from debt service relief lack large international diaspora networks (limiting their capacity to increase remittances), while those with established diaspora channels face structural exclusion of traditional debt markets, rendering debt service relief ineffective. These insights introduce nuance in how alternative finance sources can replace foreign aid.

econ.GN↗

arXiv2026

Mapping urban segregation through co-residence network reconstruction

Urban segregation poses a critical challenge for cities, exacerbating inequalities, social tensions, fears, and polarisation. It emerges from the interplay of socio-economic disparities, housing constraints, and residential preferences, and can disproportionately affect migrant communities. Here, we study residential segregation in Vienna using a city-wide administrative snapshot of registered residents, covering the full foreign population and Austrian nationals at the district level. We introduce a network-based approach by constructing a statistically validated co-residence network in which nodes represent nationalities and links capture whether pairs of groups live in the same districts more or less often than expected under a population-size-preserving null model. Applying community detection to this network reveals two major clusters of nationalities with distinct co-residence patterns. These clusters are systematically associated with district-level income disparities and diversity, while also reflecting the geographical proximity of countries of origin, with nationalities from nearby regions tending to share similar residential patterns within Vienna. Our results show how network methods can provide an intuitive and interpretable map of urban residential sorting, complementing traditional segregation indices and highlighting the multiple dimensions underlying migrant integration in diverse cities.

physics.soc-ph↗

arXiv2026

Conflict, mobility and fragmentation in the African interurban network

Roads make regional integration possible, but they also concentrate risk. When violence reaches a corridor that carries regional movement, the consequences can extend beyond the attacked place. We study this problem in Africa by combining interurban road data, georeferenced conflict events, and bilateral migration flows. Using a Hawkes-style self-exciting memory kernel, we estimate accumulated conflict intensity near roads from 2019 to 2022, and we route modelled movement between cities along the road network. As an empirical check on these modelled corridor flows, we show that country pairs connected by routes with higher accumulated conflict have lower bilateral migration. The association remains negative across alternative assumptions about spatial decay and is strongest for paths that cross regions, consistent with a corridor-deterrence channel rather than only displacement from violent places. We then use cascade and percolation simulations to examine how local disruptions propagate through the road network. Most simulated disruptions isolate relatively small populations, but 18.6% isolate more than one million people, and the largest isolates 13.3 million. Removing roads in order of conflict intensity reveals a tipping point, at which the giant connected component falls from 85% to 39% of the network. Our results identify the roads where violence most threatens regional integration and show how past conflict, mobility, and network structure combine to create persistent corridor vulnerability.

physics.soc-ph↗

arXiv2026

An Agent-Based Model for Migration Decision-Making Under Higher Frequency of Extreme Climate Events

This paper develops an agent-based model of climate-related human migration that links repeated environmental shocks to individual migration decision-making through the joint evolution of perceived risk, aspirations to migrate, and migration capability. Building on the aspirations-capabilities framework, the model represents migration as an emergent outcome of two opposing dynamics: shocks increase perceived risk and raise aspirations to move, while simultaneously eroding wealth and reducing the capability to do so. This interaction generates non-linear mobility patterns, including immobility under rising climate stress. Agents are embedded in a spatially heterogeneous shock environment, and their migration capability is further shaped by local conditions and diaspora support. Results show that more frequent shocks can initially increase migration pressure but eventually trap vulnerable agents in place as resources decline. Climate shocks amplify existing income inequalities in mobility outcomes, with lower-income agents more likely to become trapped or remain acquiescently immobile, while higher-income agents retain greater flexibility to migrate or choose voluntary immobility.

physics.soc-ph↗

arXiv2026

Scaling and Population Loss in Mexican Urban Centres

Despite its pervasive implications, many cities worldwide continue to expand in a fragmented, horizontal manner. We analyse urban growth dynamics in 69 Mexican metropolitan areas from 1990 to 2020 using census data, developing a model of urban form change based on population size, density, and spatial configuration. We employ a radial probability density function and the urban expansion factor to create a framework for comparing urban expansion over time and across different regions. Over the past three decades, Mexico's urban population has nearly doubled. However, populations have shifted outward, resulting in a decline of 2.5 million residents in central areas. Our analysis shows that distances from the city centre have increased by 28% on average, driven by population losses in central zones combined with growth in peripheral regions.

physics.soc-ph↗

arXiv2026

Observing cities as a complex system

Cities are some of the most intricate and advanced creations of humanity. Most objects in cities are perfectly synchronised to coordinate activities such as jobs, education, transportation, entertainment, and waste management. Although each city has its own characteristics, some commonalities can be observed across most cities, such as issues related to noise, pollution, segregation, and others. Further, some of these issues might be accentuated in larger or smaller cities. For example, with more people, a city might experience more competition for space, so rents would be higher. The urban scaling theory provides a framework for analysing cities in terms of their size. New data for analysing urban scaling theory allow for an understanding of how urban metrics change with population size, whether they apply across most regions, or whether patterns correspond only to some countries or regions. Yet, reducing a city and all its complexity to a single indicator might simplify urban areas to the extent that their disparities and variations are overlooked. Often, the differences in living conditions across different parts of the same city are greater than the degree of variation observed between cities. For example, in terms of rent or crime, within-city variations might be more significant than between cities. Here, we review some urban scaling principles and explore ways to analyse variations within the same city.

physics.soc-ph↗

arXiv2026

Who burdens the welfare state? Migration and ageing in housing, education, and healthcare demand

Political discourse attributes the pressure on European welfare systems to foreign nationals. Yet projections of service demand rarely disaggregate service demand by citizenship status. We develop a structural demographic model and project healthcare, education, and housing demand in Austria through 2050, disaggregated by citizenship status and regions across migration scenarios. We find that migration, ageing, and fertility shape each sector differently. In healthcare, the ageing of Austrian nationals contributes 4.7 times more to demand growth than immigration, with the most acute pressures in rural, low-migration regions. In housing, migration accounts for the entire net growth in demand, concentrated in metropolitan hubs. In education, aggregate demand contracts regardless of migration assumptions, whereas future needs are driven more by the births of foreigners in Austria than by new arrivals. Foreign nationals consume services in proportion to their demographic weight, with deviations explained by age structure rather than over-utilisation. These results show that the drivers of service demand are sector-specific: migration restrictions could ease housing pressure, but would not address ageing-driven healthcare demand and may accelerate contraction in the education system.

physics.soc-ph↗

arXiv2026

Interplay between social contact and media exposure in the overestimation of racial diversity in the U.S

The general population systematically overestimates the size of minority groups, yet how these misperceptions vary across racial groups and geographical scales remains poorly understood. Using a purpose-built survey of the U.S. population, we examine overestimation of people of color (PoC) communities across four nested geographical scales: neighborhood, city, state, and nation. Our results demonstrate that overestimation is both scale- and group-dependent: the probability of overestimation increases progressively from local to national levels, and people of color overestimate their own group size more frequently than white people do at both the neighborhood and national levels. Among white respondents, we identify a scale-dependent divide in exposure mechanisms: direct interethnic social contact is the primary correlate of overestimation at local levels, whereas perceived frequency of coverage of people of color in news dominates at the national level. Furthermore, across both groups, frequent news consumption is associated with reduced rates of overestimation, while frequent social media use is associated with higher rates. These findings suggest that overestimation is real and present across scales and groups. This in turn can foster an `illusion of diversity', potentially undermining support for equity-promoting policies by creating the erroneous belief that representation goals have already been achieved.

physics.soc-ph↗

arXiv2025

Why Locking Up Cartel Members Does not Work

One of the core strategies to reduce cartel violence is by directly targeting members with law enforcement. Whether targeting leaders, disrupting parts of the organisation, or incarcerating members, the purpose is to reduce the strength of cartels directly. Most security strategies result in increased incarceration rates. Yet its effectiveness in addressing organised crime remains unclear, particularly if it fails to prevent recidivism upon release from jail. Here, a model is constructed to quantify cartel participation across generations, where individuals are recruited, age over time, and exit cartels as victims of a homicide or due to incapacitation, or retirement. Incarcerating cartel members prevents less than 10% of cartel offences. Additionally, doubling penalties would reduce cartel members' potential by less than 5%, thereby challenging proposals for stricter rules. Yet, rehabilitation after prison, often neglected as an integral part of the security strategy, could be more effective in lowering cartel crimes.

physics.soc-ph↗

arXiv2025

Migrants as First Responders: A Global Estimate of Disaster-Driven Remittances

International remittances represent a vital source of disaster adaptation finance for households around the world, yet their responsiveness to environmental disasters remains poorly quantified. We reveal a previously unmeasured global macro-financial system of international migrant diasporas remittances response to the occurrence of disasters in the country of origin. We do so by developing a structural model simulating individual remittance decisions, calibrated with global disaster records and bilateral monthly remittances flow data from the period 2010-2019. Our analysis reveals that approximately 332 billion USD (5.46\% of total remittances) were mobilized specifically in response to earthquakes, floods, storms, and droughts over the decade. Earthquakes triggered the largest remittance responses per person affected, while droughts elicited the smallest. The model also identifies significant variation in diaspora groups' capacity to activate financial support. These findings establish remittances as a substantial yet limited form of disaster finance, highlighting their importance and limitations in building resilience against future environmental shocks.

econ.GN↗

arXiv2025

Arriving Young, Leaving Old(er): Age-Structured International Migration on Subnational Scale in Austria

Modelling migration is complicated, as people move for many reasons. Some leave their country for the first time, others return to places they once called home, or move on to new destinations. However, most models focus only on who arrives, missing the full picture of how migrant populations evolve. We introduce a model for diaspora flows that estimates both arrivals and exits using daily migration flow rates, disaggregated by age and nationality. Drawing on high-resolution administrative data from Austria covering over 1.8 million foreign nationals, the model allocates these movements across more than 2,000 municipalities based on the size of local diaspora communities. We find that exits are not exceptions but a consistent and predictable feature across all groups. Migration rejuvenates Austria's population, as both arriving and departing migrants are younger than the average resident. This effect has distinct age-geography patterns: younger migrants are drawn to cities, while older migrants are more evenly distributed in the country. By capturing both arrivals and exits simultaneously, our approach provides a more comprehensive and interpretable picture of migration dynamics, how populations change over time, and how they are influenced by space, age, and national origins.

physics.soc-ph↗

arXiv2025

Metros reduce car use in European cities but trams do not

Despite the evident drawbacks, car ownership and usage continue to rise globally, leading to increased pollution and urban sprawl. As alternatives, Active Mobility and Public Transport are promoted for their health, economic, and environmental benefits. However, the efficiency of Public Transport varies widely. Metro systems, in particular, offer a high-capacity, long-distance solution, but they are expensive and only found in a limited number of cities. Trams, on the other hand, may serve as a substitute. This study compares the modal share in European cities, analysing the differences between those that have a metro, a tram, or neither. The analysis draws on a comprehensive dataset from CitiesMoving.com, which compiles and harmonises mobility surveys from around the world according to the ABC framework (A for Active mobility, B for Bus and other forms of Public Transport, and C for Cars). Findings reveal that cities with a metro have a significantly lower share of car journeys than those with only a tram or no rail system.

physics.soc-ph↗

arXiv2025

Most Western African migrants remain local and travel short distances

Migration patterns are complex and context-dependent, with the distances migrants travel varying greatly depending on socio-economic and demographic factors. While global migration studies often focus on Western countries, there is a crucial gap in our understanding of migration dynamics within the African continent, particularly in West Africa. Using data from over 60,000 individuals from eight West African countries, this study examines the determinants of migration distance in the region. Our analysis reveals a bimodal distribution of migration distances: while most migrants travel locally within a hundred km, a smaller yet significant portion undertakes long-distance journeys, often exceeding 3,000 km. Socio-economic factors such as employment status, marital status and level of education play a decisive role in determining migration distances. Unemployed migrants, for instance, travel substantially farther (1,467 km on average) than their employed counterparts (295 km). Furthermore, we find that conflict-induced migration is particularly variable, with migrants fleeing violence often undertaking longer and riskier journeys. Our findings highlight the importance of considering both local and long-distance migration in policy decisions and support systems, as well as the need for a comprehensive understanding of migration in non-Western contexts. This study contributes to the broader discourse on human mobility by providing new insights into migration patterns in Western Africa, which in turn has implications for global migration research and policy development.

physics.soc-ph↗

arXiv2025

Urban Sprawl Is Associated with Reduced Access and Increased Costs of Water and Sanitation

Many cities are expanding in areas with scarce rainfall and limited water retention capacity, and are also becoming elongated and sprawled, making it harder to deliver services. This study quantifies the impact of urban form on access to water. We craft comparable urban forms for over 100 cities in Asia, Africa, and Latin America. For each city, we analyse the distance to the centre, one of the most critical features of cities. We introduce two metrics: remoteness, which quantifies the distance of any location to the city centre, and sparseness, a population-weighted average of all locations. We find that less remote areas have higher average income, are closer to critical infrastructure and have higher access to sewage and piped water. Sparser cities have higher water tariffs, lower proximity to critical infrastructure, and lower access to sewage and piped water. Finally, we model urban expansion under three scenarios: compact, persistent, and horizontal growth. When cities expand through compact growth rather than horizontal expansion, 220 million more people could gain access to piped water, and 190 million more to sewage services.

physics.soc-ph↗

arXiv2025

Reducing Cartel Violence: The Mexican Dilemma Between Social and Security Spending

Organised crime in Mexico threatens societal stability and public safety, driving pervasive violence and economic disruption. Despite security investments and social programs designed in part to reduce involvement in crime, cartel power and violence continue to persist. This study evaluates existing policies and introduces a novel framework using optimal control theory to analyse cartel dynamics. Specifically, by modelling resource allocation between security measures and social programs, we identify optimal strategies to mitigate the impacts of cartels. Findings reveal that Mexico's largest cartel imposes an annual economic burden exceeding \text{US\$ } 19 billion, 2.5 times the government's investment in science and technology. We further demonstrate that current budget allocations between social and security programs are nearly optimal yet insufficient to reduce cartel violence significantly. In light of these findings, we demonstrate that achieving meaningful harm reduction would require a significantly larger budget and would take over a decade, even with increased funding.

physics.soc-ph↗

arXiv2025

What is the best shape of a city

Urban form plays a crucial role in shaping transportation patterns, accessibility, energy consumption, and more. Our study examines the relationship between urban form and transportation energy use by developing a parametric model that simulates city structures and their impact on travel distances. We explore various urban morphologies, including sprawling, elongated, compact, and vertically concentrated cities, and consider five urban profiles: "needle," "pyramid," "pancake," "bowl," and "ring." We designed an interactive visualisation and calculator that enables the analysis of these effects, providing insights into the impact of various urban configurations. Our model quantifies the average commuting distances associated with these forms, demonstrating that compact and centrally dense cities minimise the total travel distance in cities.

physics.soc-ph↗

arXiv2025

Refugees' path to legal stability is long and systematically unequal

Legal systems shape not only the recognition of migrants and refugees but also the pace and stability of their integration. Refugees often shift between multiple legal classifications, a process we refer to as the "legal journey". This journey is frequently prolonged and uncertain. Using a network-based approach, we analyze legal transitions for over 350,000 migrants in Austria (2022 to 2024). Refugees face highly unequal pathways to stability, ranging from two months for Ukrainians to nine months for Syrians and 20 months for Afghans. Women, especially from these regions, are more likely to gain protection; Afghan men wait up to 30 months on average. We also find that those who cross the border without going through official border controls face higher exit rates and lower chances of securing stable status. We show that legal integration is not a uniform process, but one structured by institutional design, procedural entry points, and unequal timelines.

physics.soc-ph↗

arXiv2025

The gravity model for social systems

Gravity is one of the most prominent models used across various social areas, including economics, demography, mobility, politics, and other systems where spatial interactions are relevant. The model represents a flexible approach that captures important regularities that might be detected when thousands or millions of people are observed, i.e. bigger origins and bigger destinations increase the intensity of interactions, but it tends to decay with longer distances between them. Therefore, the number of interactions between two locations is frequently modelled with an equation that resembles Newton's Law of Gravitation (also known as the Law of Gravity). Here, I explore different aspects, i.e. essential components, techniques for estimating the parameters, interpretation of results, and settings where gravity is a helpful tool, including mobility and migration.

physics.soc-ph↗