Hasil untuk "Colonies and colonization. Emigration and immigration. International migration"

Brandon Runnels

Grain boundary (GB) migration governs microstructure evolution and can mediate plastic deformation through sliding or shear coupling. Numerous experimental and numerical studies have reported a wide range of behaviors associated with boundary migration, such as defect emission or mode switching. Notably, recent studies have reported directionally asymmetric migration rates under symmetric loading, attributing this behavior to intrinsically asymmetric mobility; however, a mechanistic mesoscale explanation for this behavior remains lacking. In this work, we introduce a constitutive flow rule for grain-boundary eigendeformation within a multiphase-field framework, in which interfacial shear evolves in response to its mechanically conjugate driving force through the phase field Allen-Cahn equations. The formulation systematically employs regularized grain boundary shear kinematics informed by crystallography, and enables elastic compatibility to modulate boundary motion. Migration thresholds, residual back-stress, and apparent directional asymmetry appear naturally as emergent mechanical behavior. Simulations of symmetric and asymmetric tilt grain boundaries under mechanical, synthetic, and curvature-driven loading reveal persistent defect-like residuals following incompatible migration, transitions from planar motion to lamination at large inclinations, and even "ratcheting" behavior. These results provide a mechanically transparent explanation for behaviors such as effective mobility asymmetry and establish elastic compatibility as a constitutive mechanism in mesoscale models of boundary-mediated plasticity.

Thang-Long Nguyen-Ho, Minh-Khoi Pham, Hoang-Bao Le

This report details our methodology and results developed for the Multilingual E-commerce Search Competition. The problem aims to recognize relevance between user queries versus product items in a multilingual context and improve recommendation performance on e-commerce platforms. Utilizing Large Language Models (LLMs) and their capabilities in other tasks, our data-centric method achieved the highest score compared to other solutions during the competition. Final leaderboard is publised at https://alibaba-international-cikm2025.github.io. The source code for our project is published at https://github.com/nhtlongcs/e-commerce-product-search.

Beibei Liu, Clément Baruteau, Zhaohuan Zhu et al.

This study investigates the orbital migration of a planet located near the truncated edge of protoplanetary disks, induced by X-ray photo-evaporation originating from the central star. The combined effects of turbulent viscous accretion and stellar X-ray photo-evaporation give rise to the formation of a cavity in the central few astronomical units in disks. Once the cavity is formed, the outer disk experiences rapid mass loss and the cavity expands inside out. We have conducted 2D hydrodynamical simulations of planet-disk interaction for various planet masses and disk properties. Our simulations demonstrate that planets up to about Neptune masses experience a strong positive corotation torque along the cavity edge that leads to sustained outward migration -- a phenomenon previously termed {\it rebound} migration. Rebound migration is more favorable in disks with moderate stellar photo-evaporation rates of ${\sim}10^{-8} ~ \rm M_{\odot}\,yr^{-1}$. Saturn-mass planets only experience inward migration due to significant gas depletion in their co-orbital regions. In contrast, Jupiter-mass planets are found to undergo modest outward migration as they cause the residual disk to become eccentric. This work presents the first 2D hydrodynamical simulations that confirm the existence and viability of rebound outward migration during the inside-out clearing in protoplanetary disks.

Juliette Becker

In this work, we investigate the dynamical survival of short-period inner planets during the high-eccentricity tidal migration of companion exterior giant planets. Using a combination of analytic arguments and N-body simulations including equilibrium tides and general relativistic precession, we find the boundary in parameter space where an inner companion can remain dynamically stable. We find that survival requires a periastron separation exceeding roughly 14 mutual Hill radii at closest approach. Below this threshold, secular eccentricity exchange, orbit crossing, and/or tidal evolution can lead to the destruction of the inner planet. We apply our methodology to the current exoplanet sample and find that none of the known systems containing a short-period giant and an inner companion could have assembled via high-eccentricity tidal migration. However, warm Jupiters with larger periastron distances ($q_{\mathrm{out}} \sim 0.05-0.08$ AU, corresponding to final observed semi-major axis values $a_{\mathrm{out}} \sim 0.10-0.16$ AU) can allow the survival of short-period inner planets while potentially also circularizing on $\lesssim 1$ Gyr timescales. Our results provide a framework for distinguishing disk migration from tidal migration in observed multi-planet systems containing close-in gas giants.

Sylvia Soto-Alvarado, Jorge Parada Morollón, Fernando Gil-Alonso

Resumen Se analiza la evolución de las condiciones socioeconómicas del conjunto de la población inmigrante y de tres colectivos con mayor representación -venezolanos, peruanos y haitianos- en comparación con la población chilena, en cuanto a ingresos económicos y situación de pobreza entre los años 2015 y 2022 a fin de observar el impacto de la pandemia COVID-19 en cada grupo. Para ello, se realizó un análisis estadístico descriptivo e inferencial utilizando los microdatos de la encuesta CASEN de los años 2015, 2017, 2020 y 2022. Los principales resultados muestran que la población chilena y migrante fueron afectadas socioeconómicamente en forma desigual por la pandemia, y que, en el caso de venezolanos, haitianos y peruanos, ya habían sufrido una disminución de sus condiciones socioeconómicas previas a la pandemia, pero la situación empeoró con la llegada de esta y la implementación de medidas gubernamentales para combatir su expansión.

Rasul Dent, Juliette Janès, Thibault Clérice et al.

Whether or not several Creole languages which developed during the early modern period can be considered genetic descendants of European languages has been the subject of intense debate. This is in large part due to the absence of evidence of intermediate forms. This work introduces a new open corpus, the Molyé corpus, which combines stereotypical representations of three kinds of language variation in Europe with early attestations of French-based Creole languages across a period of 400 years. It is intended to facilitate future research on the continuity between contact situations in Europe and Creolophone (former) colonies.

Divya Sharma

The paper presents findings from a comprehensive study examining the saving and credit behaviors of low-income households residing in unauthorized colonies within a metropolitan area. Utilizing a dual approach, the study engaged in prolonged fieldwork, including repeated fortnightly interviews with selected households and a one-time primary survey with a larger sample size. The research meticulously analyzed the financial lives of these households, focusing on their saving and credit behaviors and assessing the accessibility and intensity of usage of financial instruments available to them. Through suitable regression models, the study identified key factors influencing the usage of financial instruments among low-income households. Transaction costs, convenience, and financial knowledge emerged as significant determinants impacting both usage decisions and the intensity of usage. The research underscores the importance of addressing demand side factors to ensure widespread financial services usage among low-income groups. Efforts to reduce time costs, enhance product accessibility and liquidity, and augment financial literacy are essential for fostering financial inclusion in unauthorized colonies. The findings highlight the imperative of moving beyond mere financial access towards promoting universal usage to realize the full benefits of financial inclusion.

Alex Guedes Brum

Resumo Este artigo explica o repentino interesse da Turquia em implementar políticas de vinculação da diáspora durante o período em que Erdoğan ocupou o cargo de primeiro-ministro do país (2003-2014). Argumenta-se que a evolução dessas políticas foi resultado de uma combinação de fatores domésticos, transnacionais e internacionais: internamente, a ascensão do AKP ao poder resultou em reformas econômicas e políticas e na promoção de uma nova identidade nacional baseada no neo-otomanismo e no nacionalismo sunita-muçulmano. Transnacionalmente, a crescente influência socioeconômica e política das comunidades turcas nos países de abrigo instou a Turquia a reconsiderar a eficácia de sua diáspora como fonte de influência no exterior, bem como um eleitorado em eleições nacionais. Acontecimentos internacionais também moldaram a nova agenda diaspórica do país, como o aumento do poder de barganha vis-à-vis a UE desde o início dos anos 2000 e o aumento da islamofobia no pós-11 de setembro.

Cristián Felipe Orrego Rivera

Resumen La trama burocrática a la cual se ve enfrentada la migración haitiana en Chile para conseguir la regularización y la residencia definitiva, genera un espacio de espera marcado por la incertidumbre y el riesgo, y configura un horizonte de aspiración inestable. En el presente artículo, se analiza cómo el vudú, en tanto elemento forjador de relaciones comunitarias y de protección, constituye un capital para que las personas haitianas en Chile enfrenten de mejor manera las problemáticas derivadas de la negligencia de la gestión migratoria.

Riikka Era

de Marchis, Giorgio

Resenha de Girotto, A. (2022). Pesadelos, Excessos, Utopias. A Representação do Poder em Angola entre Literatura e Artes Visuais. Vila Nova de Famalicão: Edições Húmus, 162 pp.

Dezso Mate

Foreword of the thematic issue Roma LGBTI, Feminist Movement and Scholarship

Elisangela da Silva Machieski

A pedofilia não está nas definições legais; ela não consta como crime. O que se pode considerar crime são as práticas que dela resultam. Todo dia, porém, ouvimos a expressão ‘crime de pedofilia’. Ao utilizar como fonte o cinema e a revista Veja, dentro do recorte temporal selecionado de 1996 a 2010, o objetivo é perceber como o termo pedofilia foi entendido. Para refletir sobre o uso do termo em questão, será utilizada a análise por oposição, que consiste em entender o conceito em sentido que se opõe ao de outros termos utilizados para retratar a violência sexual contra crianças e adolescentes. Os resultados obtidos se encaixam na perspectiva de que o conceito de pedofilia é utilizado de maneira errônea no senso comum, no cinema e na Revista Veja.

TianZhang He, Adel N Toosi, Rajkumar Buyya

By integrating Software-Defined Networking and cloud computing, virtualized networking and computing resources can be dynamically reallocated through live migration of Virtual Machines (VMs). Dynamic resource management such as load balancing and energy-saving policies can request multiple migrations when the algorithms are triggered periodically. There exist notable research efforts in dynamic resource management that alleviate single migration overheads, such as single migration time and co-location interference while selecting the potential VMs and migration destinations. However, by neglecting the resource dependency among potential migration requests, the existing solutions of dynamic resource management can result in the Quality of Service (QoS) degradation and Service Level Agreement (SLA) violations during the migration schedule. Therefore, it is essential to integrate both single and multiple migration overheads into VM reallocation planning. In this paper, we propose a concurrency-aware multiple migration selector that operates based on the maximal cliques and independent sets of the resource dependency graph of multiple migration requests. Our proposed method can be integrated with existing dynamic resource management policies. The experimental results demonstrate that our solution efficiently minimizes migration interference and shortens the convergence time of reallocation by maximizing the multiple migration performance while achieving the objective of dynamic resource management.

Ivars Dzalbs, Tatiana Kalganova

Ant Colony algorithm has been applied to various optimization problems, however most of the previous work on scaling and parallelism focuses on Travelling Salesman Problems (TSPs). Although, useful for benchmarks and new idea comparison, the algorithmic dynamics does not always transfer to complex real-life problems, where additional meta-data is required during solution construction. This paper looks at real-life outbound supply chain problem using Ant Colony Optimization (ACO) and its scaling dynamics with two parallel ACO architectures - Independent Ant Colonies (IAC) and Parallel Ants (PA). Results showed that PA was able to reach a higher solution quality in fewer iterations as the number of parallel instances increased. Furthermore, speed performance was measured across three different hardware solutions - 16 core CPU, 68 core Xeon Phi and up to 4 Geforce GPUs. State of the art, ACO vectorization techniques such as SS-Roulette were implemented using C++ and CUDA. Although excellent for TSP, it was concluded that for the given supply chain problem GPUs are not suitable due to meta-data access footprint required. Furthermore, compared to their sequential counterpart, vectorized CPU AVX2 implementation achieved 25.4x speedup on CPU while Xeon Phi with its AVX512 instruction set reached 148x on PA with Vectorized (PAwV). PAwV is therefore able to scale at least up to 1024 parallel instances on the supply chain network problem solved.

Maja Gostič

Članek obravnava subjektivno zaznavanje položaja izseljenih iz Slovenije med letoma 2014 in 2017. Poglobljeno je predstavljena izkušnja njihovega bivanja in dela v Avstriji in Nemčiji, ki sta prostor najbolj množičnega sodobnega izseljevanja iz Slovenije. Subjektivne izkušnje migrantov so ob podpori objektivnih statističnih podatkov pomembne za razumevanje celostne slike sodobnih ekonomskih migracij. Namen raziskave je bil pridobiti čim več informacij o migracijski izkušnji s stališča današnjega časa, pojava globalizacije in mobilnosti. Raziskava je pripomogla k razumevanju sodobnih motivov in izkušenj izseljevanja v prostoru Evropske unije.

Kathryn Volk, Renu Malhotra

We present numerical simulations of giant planet migration in our solar system and examine how the speed of planetary migration affects inclinations in the resulting population of small bodies (test particles) scattered outward and subsequently captured into Neptune's 3:2 mean motion resonance (the Plutinos) as well as the hot classical Kuiper belt population. We do not find a consistent relationship between the degree of test particle inclination excitation and e-folding planet migration timescales in the range 5-50 Myr. Our results present a counter-example to Nesvorny 2015's finding that the Plutino and hot classical inclinations showed a marked increase with increasing e-folding timescales for Neptune's migration. We argue that these differing results are likely due to differing secular architectures of the giant planets during and after migration. Small changes in the planets' initial conditions and differences in the numerical implementation of planet migration can result in different amplitudes of the planets' inclination secular modes, and this can lead to different final inclination distributions for test particles in the simulations. We conclude that the observed large inclination dispersion of Kuiper belt objects does not require Neptune's migration to be slow; planetary migration with e-folding timescales of 5, 10, 30, and 50 Myr can all yield inclination dispersions similar to the observed Plutino and hot classical populations, with no correlation between the degree of inclination excitation and migration speed.

O. Kulikova, S. B. Popov, V. V. Zhuravlev

Planet migration originally refers to protoplanetary disks, which are more massive and dense than typical accretion disks in binary systems. We study planet migration in an accretion disk in a binary system consisting of a solar-like star hosting a planet and a red giant donor star. The accretion disk is fed by a stellar wind. %, disk self-gravity is neglected. We use the $α$-disk model and consider that the stellar wind is time-dependent. Assuming the disk is quasi-stationary we calculate its temperature and surface density profiles. In addition to the standard disk model, when matter is captured by the disk at its outer edge, we study the situation when the stellar wind delivers matter on the whole disc surface inside the accretion radius with the rate depending on distance from the central star. Implying that a planet experiences classical type I/II migration we calculate migration time for a planet on a circular orbit coplanar with the disk. Potentially, rapid inward planet migration can result in a planet-star merger which can be accompanied by an optical or/and UV/X-ray transient. We calculate timescale of migration for different parameters of planets and binaries. Our results demonstrate that planets can fall on their host stars within the lifetime of the late-type donor for realistic sets of parameters.

Matteo Campo, Simon K. Schnyder, John J. Molina et al.

The migration of cells is relevant for processes such as morphogenesis, wound healing, and invasion of cancer cells. In order to move, single cells deform cyclically. However, it is not understood how these shape oscillations influence collective properties. Here we demonstrate, using numerical simulations, that the interplay of directed motion, shape oscillations, and excluded volume enables cells to locally "synchronize" their motion and thus enhance collective migration. Our model captures elongation and contraction of crawling ameboid cells controlled by an internal clock with a fixed period, mimicking the internal cycle of biological cells. We show that shape oscillations are crucial for local rearrangements that induce ordering of internal clocks between neighboring cells even in the absence of signaling and regularization. Our findings reveal a novel, purely physical mechanism through which the internal dynamics of cells influences their collective behavior, which is distinct from well known mechanisms like chemotaxis, cell division, and cell-cell adhesion.

John Potts

This essay charts a brief intellectual history of the futures – both utopian and dystopian – conceived in the twentieth and twenty-first centuries. It traces perspectives on the future since 1909, when the term ‘futurism’ was coined in the publication of the ‘The Founding and Manifesto of Futurism’. The essay maps changes in the vision of the future, taking a chronological approach in noting developments in the discourse on the future. A prominent theme in pronouncements on the future is technological progress, first in relation to industrial technology, later in the context of post-industrial or information technology. A turning-point in this discourse can be isolated around 1973, when ideas of technological progress begin to be challenged in the public sphere; from that date, environmental concern becomes increasingly significant in discussions of the future.